CA2500048A1 - Method of cleaning a potable water distribution piping system - Google Patents
Method of cleaning a potable water distribution piping system Download PDFInfo
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- CA2500048A1 CA2500048A1 CA 2500048 CA2500048A CA2500048A1 CA 2500048 A1 CA2500048 A1 CA 2500048A1 CA 2500048 CA2500048 CA 2500048 CA 2500048 A CA2500048 A CA 2500048A CA 2500048 A1 CA2500048 A1 CA 2500048A1
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- pipe
- section
- water
- cleaned
- sediments
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
- B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
- B08B9/027—Cleaning the internal surfaces; Removal of blockages
- B08B9/04—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes
- B08B9/053—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction
- B08B9/057—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction the cleaning devices being entrained discrete elements, e.g. balls, grinding elements, brushes
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- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Cleaning In General (AREA)
Abstract
A method of cleaning a potable or non potable water distribution piping system is described. A section of pipe to be cleaned of deposited sediments incrusted on an inner wall thereof is identified and isolated by closing valves leading to service conduits. Two fire hydrants are identified which are connected to the section of pipe to be cleaned and an air compressor is connected to a nozzle of one of these hydrants. A reservoir containing a sediment dislodging product is connected to another hydrant nozzle of that fire hydrant. One of the valves in the vicinity of the fire hydrant to which the air compressor is connected is open to create a minimal water flow. The nozzle of the other fire hydrant is opened and the compressor is operated to inject air under pressure inside the section of pipe to be cleaned. Simultaneously, the sediment dislodging product is injected into the pipe section to be cleaned through the fire hydrant. The water turbulating through the section of pipe to be cleaned is flushed by opening a nozzle of the other fire hydrant.
Description
r METHOD OF CLEANING A POTABLE WATER
DISTRIBUTION PIPING SYSTEM
TECHNICAL FIELD
toooll The present invention relates to a non-structural pipe rehabilitation method for cleaning a potable or non-potable water distribution piping system and which relies on a synergetic combination of thermo, hydro-pneumatic and chemical processes to remove accumulated deposits on the inner wall of sections of such pipes.
BACKGROUND ART
tooo2l Municipalities and industries are faced with a tremendous challenge to rehabilitate the underground water infrastructure. Specialists in the field and most municipal engineers will confirm that the service life of more than 50°s of the buried water infrastructure has reached the end of their service lives. According to the USEPA, the needs are numbered at $77 Billion dollars to maintain or replace the underground water distribution pipes in the next 20 years. In several cities or town, this problem covers 40% to 60% of the networks . In summary, thousands of miles of pipe are in need of repair at this time.
tooo3l Considering the enormous cost to meet this challenge, public and private corporations are looking at different alternatives to restore the pipes up to their original standards. The most common problem is the scale deposition and sedimentation inside the pipe, reducing the pipe hydraulic carrying capacity. Among all available rehabilitation methods available on the market today, trenchless rehabilitation technologies seem to be the most interesting since they are safe, cost-effective and most important, cause little or no inconvenience to the public and to the environment.
DISTRIBUTION PIPING SYSTEM
TECHNICAL FIELD
toooll The present invention relates to a non-structural pipe rehabilitation method for cleaning a potable or non-potable water distribution piping system and which relies on a synergetic combination of thermo, hydro-pneumatic and chemical processes to remove accumulated deposits on the inner wall of sections of such pipes.
BACKGROUND ART
tooo2l Municipalities and industries are faced with a tremendous challenge to rehabilitate the underground water infrastructure. Specialists in the field and most municipal engineers will confirm that the service life of more than 50°s of the buried water infrastructure has reached the end of their service lives. According to the USEPA, the needs are numbered at $77 Billion dollars to maintain or replace the underground water distribution pipes in the next 20 years. In several cities or town, this problem covers 40% to 60% of the networks . In summary, thousands of miles of pipe are in need of repair at this time.
tooo3l Considering the enormous cost to meet this challenge, public and private corporations are looking at different alternatives to restore the pipes up to their original standards. The most common problem is the scale deposition and sedimentation inside the pipe, reducing the pipe hydraulic carrying capacity. Among all available rehabilitation methods available on the market today, trenchless rehabilitation technologies seem to be the most interesting since they are safe, cost-effective and most important, cause little or no inconvenience to the public and to the environment.
Iooo4) The accumulation of sediment on the pipe inner walls has tremendous negative consequences to the general public. Inconveniences include the restriction of flow for fire protection, higher energy cost to pump the water in the system due to the restrictions in the pipe, poor water quality to the customers because of the reddish colour occurring in events of increased water demands such as pipe flushing, or any other use of water from the hydrants for street cleaning, watering, etc.
Iooo5) One of the main concerns is for fire protection.
New government regulations provide Fire Protection guidelines that any public water distribution system provides a predetermined volume of water at a hydrant as per its geographical location and type of protection coverage, i.e., residential, industrial, or commercial.
Iooos) When water pipes get severely encrusted over time, the fire hydrants do not provide access to the flows for which the distribution system was originally designed. This problem forces fire protection personnel to modify their fire fighting strategies, which are then often compromised and diminished. In addition, the urban development plan is also compromised, disfavouring low flow areas.
fooo~) When the accumulation of sediment is the problem, non-structural rehabilitation methods are often the solution of choice. However, one must confirm the residual structural condition of the inner pipe wall before determining the best rehabilitation method to choose. All non-structural rehabilitation methods have benefits, but vary in performance, safety and costs.
Iooos) Non-structural rehabilitation methods include the use of powerful toxic acid circulating inside the pipe to soften and dislodge the sediments. Such are disclosed in U.S. Patent No. 5,885,364, No. 5,360,488 5, No. 5,680,877 and No 5, 800, 629. Counting only on the recurring effect of the acid to dislodge the hardened deposits on the pipe wall, the soaking time period is very long.
tooos) One of the disadvantages of that technique is the general public conception and reluctance to the use of the toxic acid in potable water systems. Other areas of concern include the risk to the environment, infiltration of the toxic acid in other parts of the system because of non-tight main valves or service connection lines, danger to the manpower that must execute the fieldwork and manipulate the acid, and the prolonged interruption of potable water service to customers.
toooio) Because of the toxic property of the acid, leaks are often caused on the pipe during the course of the work.
The situation then becomes very dangerous and a health risk for those that must come in contact with the product to clean the pipe and fix the leak. In several cases, the government authority must be made aware immediately when a pre-determined volume of toxic acid has been freed in the environment. In addition, the strong penetrating property of the acid will tend to dislodge the deposits so much that it will clean the pipe wall all the way to its bare material, exposing the pipe wall, creating red water occurrences in the system and upsetting the general public.
toooii) It must be noted that the acid technique can only be used for water distribution systems using inhibitor products such as poly-phosphate or ortho-phosphate, as a way to capture iron particles and preventing the colouring of the water. The treatment with the inhibitor products is necessary as an integral part of the water treatment when choosing the toxic acid method as a way to clean the water pipe. This treatment is obviously an additional expense for both the product itself, and the constant monitoring. For the reasons mentioned above, most private and public water r distribution system managers are not opting for the toxic acid cleaning method.
foool2~ Another method is the use of compressed air and water. This method is called "Air Scouring", see U.S.
Patent No. 5,915,395, such method having been developed in the U.K. The method provides a cleaning of the water main in one direction, from one fire hydrant to the next.
However, this method is used mostly for the cleaning of the water main rather than for the rehabilitation, as it doesn't allow the removal of tubercles and other hardened deposits on the inner pipe wall. Air Scouring is a cleaning method often used for pipe having a Hazen-Williams coefficient (HWC) of above 80. The Hazen-Williams coefficient is the major loss calculation for water in pipes using a friction loss equation. For example, a new iron pipe has a HWC of 130. A 40-year-old pipe has a HWC ranging from 64 to 83.
The HWC gradually diminishes as the pipe gets older.
Iooo137 In summary, Air Scouring is the injection of compressed and treated air inside the water main through a fire-hydrant. Along with-the air, water is introduced in the pipe by using what is called a control valve, located downstream for the hydrant which is an existent valve only partly opened. The air, along with the water, create what is called slugs. Moving at very high velocities of above 10 fts in the main, the slugs contribute to removing the non solidified deposits. Air Scouring also include the injection of a poly-phosphate product to contribute to the cleaning. Reaction time of the poly-phosphate is very short and do not contribute to the removal of the hardened deposits.
SUMMARY OF INVENTION
tooo147 It is a feature of the present invention to provide a method of cleaning a potable or non-potable water distribution piping system which is safe, cost-effective and environmentally friendly and which is capable of restoring the hydraulic carrying capacity and/or the delivery of quality water.
fooo151 Another feature of the present invention is to provide a method of cleaning a potable water distribution piping system and wherein a sediment dislodging product is injected with air under pressure into the conduit whereby to blast the deposited sediments incrusted on the inner wall of the section of pipe being cleaned.
Iooolsl According to the above features, from a broad aspect, the present invention provides a method of cleaning a potable water distribution piping system. The method comprises the steps of identifying a section of pipe to be cleaned of deposited sediments incrusted on an inner wall thereof. Two fire hydrants connected to the section of pipe to be cleaned are also identified to define a flow path through the section of pipe to be cleaned. All valves connected to the section of pipe in the vicinity of the two fire hydrants are also identified and closed to isolate the section of pipe. An air compressor is connected to a nozzle of one of the two fire hydrants upstream of a cleaning water flow to be generated. A reservoir containing a sediment dislodging product is connected to a second hydrant nozzle of the fire hydrant having the air compressor connected thereto. One of the valves connected in the vicinity of the one fire hydrant upstream of a connection thereof with the section of pipe to be cleaned is opened whereby to create a minimal water flow therefrom into the section of pipe to be cleaned upstream of the cleaning water flow to be generated.
A hydrant nozzle of the other of the two fire hydrants is opened downstream of the cleaning water flow to be generated. The compressor is then operated to inject air under pressure inside the section of pipe to be cleaned r through the fire hydrant and simultaneously the sediment dislodging product is injected into the section of pipe to be cleaned through that fire hydrant together with the air under pressure. This creates spinning water pockets inside the section of pipe to be cleaned and the sediment dislodging product mixes with the minimal water flow admitted through the opened valve whereby to blast the deposited sediments from the section of pipe to be cleaned.
The cleaning water flow containing dislodged sediments is flushed through the other fire hydrant by an open nozzle thereof .
fooomy In association with the present invention, the following services are rendered:
1. Consultation with the client to identify the faulty pipe sections and determine the level of improvement needed.
2. Through monitoring, sampling and/or laboratory analysis, determine the exact nature of the problem.
3. Review test results and, aligned with client needs, implement all, or a combination of the following steps:
3.1. Inspect, manipulate and assess the fire hydrants, main valves and users' service lines related to the project area.
3.2. Perform leak detection and isolation tests on the pipe sections to be rehabilitated.
3.3. Clean users' service lines.
3.4. Pre-clean the pipe by using air, water and the chemical pre-cleaning solution.
3.5. Soften the deposits by using hot water, and/or a chemical cleaning solution.
3.6. Finalize the pipe cleaning by evacuating the softened and dislodged material.
r 4. Through monitoring, sampling and/or laboratory analysis, confirm the effectiveness of the rehabilitation.
BRIEF DESCRIPTION OF DRAWINGS
toooi8l A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
toooZS1 FIG. 1 is a block schematic diagram illustrating the method of cleaning a potable water distribution piping system in accordance with the present invention;
fooo2ol FIGS. 2 and 3 are schematic diagrams showing the process of blasting the incrusted sediments from the inner wall of a section of pipe being cleaned and using the method in accordance with the present invention;
toooxy FIG. 4 is a block schematic diagram showing a modification of the method as illustrated in Figure 1; and tooo22~ FIG. 5 is a block schematic diagram illustrating the method of cleaning the user lines associated with a main water conduit.
DESCRIPTION OF PREFERRED EMBODIMENTS
tooo231 The following procedure is undertaken to identify the faulty pipe sections and determine the level of improvement needed to a potable water distribution piping system. First, an evaluation and an assessment of the water distribution system are done to identify the pipe sections needing a non-structural rehabilitation. The evaluation includes the identification of pipes that have an appropriate metal thickness for a non-structural rehabilitation. The evaluation also consists in investigating the historic of leaks and breakages; the pipe material, diameter and age; the identification of sections that contribute to water quality complaints; the sections r that do not provide sufficient pressures and flows, the sections of the distribution system targeted for expansion;
the sections that are part of a rehabilitation master plan;
and the sections that show vulnerability in meeting water quality government regulations and insurance requirements pertaining to fire protection.
fooo24~ Samples are taken from the pipe sections to be cleaned for laboratory analysis. The pipe sections water samples may be kept, immediately after its collection in the field, and at all times, in a container filled with water to provide a similar condition as its day-to-day environment.
A chemical analysis of the deposits found in the pipe water samples is performed to analyze the incrusted sediments, the residual wall thickness, and the expected remaining service life.
Iooo2sl In the field, the C-Factor (roughness coefficient) of the pipe to be rehabilitated is measured using the Hazen-William coefficient as recommended by the American Water Works Association. The Hazen-Williams coefficient is the major loss calculation for the water in pipe using a friction loss equation. Another method for evaluating the pipe C-Factor is to analyze the pipes' characteristics based on the hydraulic model database.
Iooo2sl We also measure static and dynamic (residual) pressures and flow at each fire hydrant located in the project area to evaluate the true hydraulic performance of the distribution system.
toooa~~ Based on the results of the laboratory analysis, we determine the preferred water temperature, optimal chemical solution and soaking time period necessary to dissolve, dislodge and evacuate the deposits on the pipe inner wall to restore the pipe hydraulic carrying capacity during the cleaning and rehabilitation procedures. The analysis procedures may include the soaking of the pipe in t _ g _ the chosen solution and periodically observe the dissolution, softening and dislodging of the incrusted sediments. The observations are made at regular intervals at temperatures up to 180 degrees Fahrenheit for the duration of the soaking.
fooo2el Referring to Figure 1, there is shown the equipment used with the method of the present invention.
Before the start of the rehabilitation method, we inspect and perform water tightness test on the fire hydrants 15, 18, 25, 27, and 31 and the water main valves 14, 16, 17, 19, 26, 28, 29, and 32 that will be used to carry out the method. In addition, we inspect and manipulate all users' service lines 20 connected to the section of pipe 21 to be rehabilitated to confirm their proper operation. The defective fire hydrants, main valves and service lines must be repaired or replaced prior to the beginning of the rehabilitation work.
(00029) In addition to the above, we perform a leak detection test on the pipe section to be rehabilitated 21 and on the users' service lines 20 using an acoustic correlator. We also perform an isolation test on the pipe section to be rehabilitated by closing valves 17, 26, 28, and 29. To confirm the proper isolation of the pipe, we open fire hydrant 25. There should be no flow at the hydrant. If there is a flow, find and repair the defective valve(s).
fooo3o~ Cleaning of the pipe section 21 as shown in Figure 1 is a method or process using a combination of purified air, water, blasting material such as ice pellets, floatable plastic pellets, and/or any other material creating an abrasive effect, and/or a non-toxic chemical solution. The objective of the pre-cleaning is to remove the non-solidified deposits and other loose residues and sediments.
Iooo317 The method comprises closing the main valves 17, 26, 28 and 29 to isolate the pipe section to be rehabilitated 21. If necessary, the users' service lines 20 connected to the pipe sections to be rehabilitated are closed. In parallel to the valve closing operation, the air compressor 1 is connected to the fire hydrant 25 using a specially conceived hose 2 and adaptor. In addition, we hook up, to the other fire hydrant nozzle 25, a hose connected to a chemical container 22 and feed pump 23, and/or we connect the hose to a pellet container 24. This set up, based on the results of the sample laboratory tests, is used to inject the pellets and/or a non-toxic blend of surfactant and sequestering agent inside the water main.
tooo32~ The surfactant is used to penetrate the deposits 50 incrusted on the pipe wall 51, and contributes to dislodging and transporting the deposits and other residues to the exit fire hydrant 18, see Figures 2 and 3. In addition, the surfactant will promote back pressure useful to the generation of turbulences 53 and high sheer water velocities necessary to properly dislodge the scaling and hardened deposits 50. The sequestering agent softens the hard deposits and therefore helps to improve the effectiveness of the cleaning.
fooo331 Following the closing of the water main valves 17, 26, 28, and 29, fire hydrant 25 is opened. The pipe section 21 should still be filled with water. However, there should be no water flow coming out of fire hydrant 25. If not, all water main valves that were closed should be verified. It is preferable to proceed with repair if a valve is found not to be watertight.
(00034 Either valve 26, 28 or 29 are opened (valve 28 as shown in Figures 2 and 3) to create a minimal flow 55 between ten (10) gpm to fifty (50) gpm at fire hydrant 25.
Then, hydrant 18 is opened, and the air compressor 1 is turned on to inject the air under pressure inside the water pipe through the fire hydrant 25. The cubic feet per minute (CFM) is adjusted considering the pipe diameter and Hazen-Williams coefficient. Simultaneously, the chemical feed pump 23 is turned on to inject the chemical solution 22 inside the water pipe 21 through the fire hydrant 25.
fooo351 The water, mixed with the chemical solution, is then propelled inside the pipe by the compressed purified air, creating the compacted pockets 53 intermittently scrubbing on the pipe walls. Air purification is achieved by successive steps of cooling and filtering, as shown at 57 in Figure l, through multi-levels cartridge filters (not shown) in order to avoid oily contamination of the distribution system. Effective pre-cleaning is achieved when the adequate concentration of surfactant is added to the water. The chemical solution is fed in concentrations capable of generating the foam required to create the adequate back pressure. Optimum efficacy occurs when foam is produced.
foooss~ Pellets can also be used to dislodge the deposits if it is deemed necessary during the laboratory tests.
Pellets contained in the container 24 are introduced in the pipe through fire hydrant 25.
tooos7~ When foam reaches hydrant 18, the process is stopped to let the pipe section to soak for a time period determined during the sample laboratory test. The solution will then penetrate and soften the deposits 50. Following this soaking, the cleaning process is restarted for a period of time anywhere between five (5) to thirty (30) minutes based on laboratory tests results. Then, turn off the chemical feed pump 23.
(ooo3sl The pellets and/or the chemical solution are flushed away when there are no more pellets or foam showing at hydrant 18. The turbidity is measured periodically and we continue on with flushing until turbidity readings are back to near normal. Turbidity readings cannot be taken when foam and/or pellets are present in the water. Deposits removed from the surfaces contribute to the cleaning process as they become themselves abrasive material when mixed with the abrading pockets to blast away further deposits as they travel down the pipe. Velocities linked to the spinning of water pockets improve the blasting efficacy.
fooo3sl To complete the cleaning of pipe section 21, we use the same cleaning procedures in the opposite direction.
For example, hydrant 18 becomes the feed hydrant, and hydrant 25 becomes the exit hydrant. Reversing the procedure will ensure a uniform cleaning of the entire pipe length. Not surprisingly, pre-cleaning performance is better in the late section of the pipe. This is why the process is reversed to ensure a proper pre-cleaning of the entire pipe length.
fooo4o~ Adding pellets will enhance the removal of sediments and therefore contribute to reducing the soaking time needed for the rehabilitation. The cleaning operation is stopped when the turbidity readings are back to near normal.
fooo4i~ When applicable, water flushing is performed along the untreated pipe sections to flush out all the loose material that were not evacuated during the pre-cleaning.
For this example, the untreated pipe sections to be flushed are located between the water main valves 26, 28 and 29, and fire hydrant 25.
(00042 With reference now to Figure 4, there is shown the softening procedure which relies on the soaking with hot water, and/or a strong, non-toxic food grade cleaning solution to soften and break the first and hard layer of the incrusted deposits 50 found on the pipe inner wall. The other sediments, underneath the hard layer, are softer and easily removable during the hydro-mechanical cleaning phase of the procedures. The softening procedures are very similar to those described above. The major differences are that the cleaning chemical solution may be replaced with hot water, and/or with a strong, acidic chemical compound more capable of performing extensive removal of hard deposits.
This compound, added to the water, forms a very strong cleaning solution. The strong chemical cleaning solution may or may not be heated depending on the laboratory test results. Also based on laboratory test results, the soaking time of the strong chemical solution is determined to dislodge persistent deposits.
Iooo431 In addition to the equipment mentioned above, boiler 37 and associated apparatus 35, 36 and 37, is needed to allow the heating of the water and/or the strong cleaning solution. The main purpose for injecting heated liquids into a pipe is to heat the pipe material and therefore engender its expansion to splinter the sediments and provide easier access and penetration of the cleaning solution in the core of the sediments 50. As an example, the extension of a cast iron pipe is of .07 inch at every 100 feet of pipe for every l0 degrees Fahrenheit increase in pipe temperature.
fooo441 A fire hydrant 27 is selected that is not connected to the pipe section 21 to be cleaned. This fire hydrant will be used to supply the potable water necessary to feed the boiler device 37 used to heat the water. The device 37 must convey the hot liquid into a storage tank 36 using a specially conceived hose.
fooo451 As per the results of the sample laboratory tests, the water and/or the cleaning chemical solution is heated to a predetermined temperature. The hot liquid is then transferred into a watertight reservoir 36 specially conceived to store hot liquids . Once the appropriate volume of hot liquid has been poured in the storage tank, pump 35 feeds the hot liquid into the pipe section 21 through fire hydrant 25. The hot liquid slowly fills the pipe sections to be rehabilitated and will eventually come out of fire hydrant 18 as the pipe is entirely filled. We keep flushing the hot liquid at fire hydrant 18, and we monitor temperature, and close the gate valve at the hose nozzle 18' of fire hydrant 18 when the proper temperature has been reached, as determined during the laboratory tests.
X000461 If a chemical solution is used for soaking instead of hot water, the spent solution will be transferred into a tank 40 and neutralized with an alkaline material in order to safely be disposed of in the sewer system. A very small portion of liquid from the pipe section is emptied to allow a stop-and-go movement of the hot liquid. Air is injected intermittently using the compressor at fire hydrant 25 to intensify the movement of the hot liquid in the pipe. This will harmonize the liquid temperature on the entire pipe length. The hot liquid is left to soak in the pipe for a time period as determined during the laboratory tests.
fooo4~~ Following the soaking, the procedure as described above is repeated to clean the pipe and the hot water and/or strong cleaning chemical solution are evacuated along with the dissolved materials. If a chemical solution is used for soaking instead of hot water, the spent solution will be transferred into a tank 40 and neutralized with an alkaline material in order to safely be disposed of in the sewer system.
fooo4a~ Following the rehabilitation and all the steps as described above, the pipe section is disinfected using the ANSI/AWWA C651-99 standards by the American Water Works Association (AWWA).
fooo4s) Following the cleaning of the pipe section 21 and to ensure that the rehabilitation objectives have been met, the following field tests and measurements are performed:
the Hazen-Williams coefficient measurement; the leak detection using acoustic correlator; the static and dynamic pressures on the fire hydrants 18 and 25 that are included in the method are measured and also on those surrounding the project area, and the standard water quality tests including turbidity and residual chlorine are performed. The purpose of those tests is to review the hydraulic and water quality results following the pipe rehabilitation, and to confirm the level of improvement and effectiveness of the method.
fooo5ol Referring to Figure 5, there will now be described the method of cleaning the user's service lines 20 to provide full benefits related to the rehabilitation of the water main. For the service line 20, outfitted with a water meter 11, the valve 5 must be closed upstream from the meter before disconnecting the service line. The line is cut and with a hose 2, the air compressor 1 is connected thereto with a connector suitable for the type and the size of the service line 20. The hose must be equipped with a ball valve. Then, the service line valve 5 must be re-opened.
Iooosi~ For the service line not outfitted with a meter, the valve 3, located inside the building 12, must first be closed. The service line 20 must be disconnected downstream of the valve 3. The service line 20 is cut and with a hose 2 it is connected to the air compressor 1 with a connector suitable for the type and the size of the service line 20.
The hose must be equipped with a ball valve. During the installation, the exterior valve 5 remains opened.
fooos2~ When the installation of the equipment is completed, the water main valve 10, located downstream of the fire hydrant 8, must be closed to prevent the spreading of the sediments throughout the entire distribution system.
It is preferable to flush the sediments in the same course as the normal direction of flow 6 in the main pipe section 7. The procedure is not necessary if the water main is a dead end. When the valve 10 is closed, fire hydrant 8 must be fully opened. Following the opening of the fire hydrant 8, the air compressor 1 must be turned on to push the sediments down the line and the water main pipe. The compressor must deliver the proper cubic feet per minute (CFM) air pressure to ensure the removal and evacuation of all sediments incrusted inside the service line 4.
Iooos3l During the cleaning of the service line, the flushed water 9 from the hydrant 8 should be colored and the turbidity very high. It is important to flush the hydrant 8 until the water reaches a turbidity level of 10 Neophelometric Turbidity Unit (NTU) or less. As above-mentioned, this is a measurement of the cloudiness of water due to suspended particles in the water (clay, silt, rust, etc). Lower is the reading, clearer is the water. When the turbidity level is at 10 NTU or less, the air compressor 1 can be turned off. The main water valve 10 is reopened and the air compressor 1 is disconnected from the service line 20 and the water meter 11 is reconnected. The re-connection of the service line to the water main is performed to standards. Open and flush a water tap inside the building for at least five (5) minutes and proceed with water quality tests to ensure the safe use of the water.
fooos4~ It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein provided such modifications fall within the scope of the appended claims.
Iooo5) One of the main concerns is for fire protection.
New government regulations provide Fire Protection guidelines that any public water distribution system provides a predetermined volume of water at a hydrant as per its geographical location and type of protection coverage, i.e., residential, industrial, or commercial.
Iooos) When water pipes get severely encrusted over time, the fire hydrants do not provide access to the flows for which the distribution system was originally designed. This problem forces fire protection personnel to modify their fire fighting strategies, which are then often compromised and diminished. In addition, the urban development plan is also compromised, disfavouring low flow areas.
fooo~) When the accumulation of sediment is the problem, non-structural rehabilitation methods are often the solution of choice. However, one must confirm the residual structural condition of the inner pipe wall before determining the best rehabilitation method to choose. All non-structural rehabilitation methods have benefits, but vary in performance, safety and costs.
Iooos) Non-structural rehabilitation methods include the use of powerful toxic acid circulating inside the pipe to soften and dislodge the sediments. Such are disclosed in U.S. Patent No. 5,885,364, No. 5,360,488 5, No. 5,680,877 and No 5, 800, 629. Counting only on the recurring effect of the acid to dislodge the hardened deposits on the pipe wall, the soaking time period is very long.
tooos) One of the disadvantages of that technique is the general public conception and reluctance to the use of the toxic acid in potable water systems. Other areas of concern include the risk to the environment, infiltration of the toxic acid in other parts of the system because of non-tight main valves or service connection lines, danger to the manpower that must execute the fieldwork and manipulate the acid, and the prolonged interruption of potable water service to customers.
toooio) Because of the toxic property of the acid, leaks are often caused on the pipe during the course of the work.
The situation then becomes very dangerous and a health risk for those that must come in contact with the product to clean the pipe and fix the leak. In several cases, the government authority must be made aware immediately when a pre-determined volume of toxic acid has been freed in the environment. In addition, the strong penetrating property of the acid will tend to dislodge the deposits so much that it will clean the pipe wall all the way to its bare material, exposing the pipe wall, creating red water occurrences in the system and upsetting the general public.
toooii) It must be noted that the acid technique can only be used for water distribution systems using inhibitor products such as poly-phosphate or ortho-phosphate, as a way to capture iron particles and preventing the colouring of the water. The treatment with the inhibitor products is necessary as an integral part of the water treatment when choosing the toxic acid method as a way to clean the water pipe. This treatment is obviously an additional expense for both the product itself, and the constant monitoring. For the reasons mentioned above, most private and public water r distribution system managers are not opting for the toxic acid cleaning method.
foool2~ Another method is the use of compressed air and water. This method is called "Air Scouring", see U.S.
Patent No. 5,915,395, such method having been developed in the U.K. The method provides a cleaning of the water main in one direction, from one fire hydrant to the next.
However, this method is used mostly for the cleaning of the water main rather than for the rehabilitation, as it doesn't allow the removal of tubercles and other hardened deposits on the inner pipe wall. Air Scouring is a cleaning method often used for pipe having a Hazen-Williams coefficient (HWC) of above 80. The Hazen-Williams coefficient is the major loss calculation for water in pipes using a friction loss equation. For example, a new iron pipe has a HWC of 130. A 40-year-old pipe has a HWC ranging from 64 to 83.
The HWC gradually diminishes as the pipe gets older.
Iooo137 In summary, Air Scouring is the injection of compressed and treated air inside the water main through a fire-hydrant. Along with-the air, water is introduced in the pipe by using what is called a control valve, located downstream for the hydrant which is an existent valve only partly opened. The air, along with the water, create what is called slugs. Moving at very high velocities of above 10 fts in the main, the slugs contribute to removing the non solidified deposits. Air Scouring also include the injection of a poly-phosphate product to contribute to the cleaning. Reaction time of the poly-phosphate is very short and do not contribute to the removal of the hardened deposits.
SUMMARY OF INVENTION
tooo147 It is a feature of the present invention to provide a method of cleaning a potable or non-potable water distribution piping system which is safe, cost-effective and environmentally friendly and which is capable of restoring the hydraulic carrying capacity and/or the delivery of quality water.
fooo151 Another feature of the present invention is to provide a method of cleaning a potable water distribution piping system and wherein a sediment dislodging product is injected with air under pressure into the conduit whereby to blast the deposited sediments incrusted on the inner wall of the section of pipe being cleaned.
Iooolsl According to the above features, from a broad aspect, the present invention provides a method of cleaning a potable water distribution piping system. The method comprises the steps of identifying a section of pipe to be cleaned of deposited sediments incrusted on an inner wall thereof. Two fire hydrants connected to the section of pipe to be cleaned are also identified to define a flow path through the section of pipe to be cleaned. All valves connected to the section of pipe in the vicinity of the two fire hydrants are also identified and closed to isolate the section of pipe. An air compressor is connected to a nozzle of one of the two fire hydrants upstream of a cleaning water flow to be generated. A reservoir containing a sediment dislodging product is connected to a second hydrant nozzle of the fire hydrant having the air compressor connected thereto. One of the valves connected in the vicinity of the one fire hydrant upstream of a connection thereof with the section of pipe to be cleaned is opened whereby to create a minimal water flow therefrom into the section of pipe to be cleaned upstream of the cleaning water flow to be generated.
A hydrant nozzle of the other of the two fire hydrants is opened downstream of the cleaning water flow to be generated. The compressor is then operated to inject air under pressure inside the section of pipe to be cleaned r through the fire hydrant and simultaneously the sediment dislodging product is injected into the section of pipe to be cleaned through that fire hydrant together with the air under pressure. This creates spinning water pockets inside the section of pipe to be cleaned and the sediment dislodging product mixes with the minimal water flow admitted through the opened valve whereby to blast the deposited sediments from the section of pipe to be cleaned.
The cleaning water flow containing dislodged sediments is flushed through the other fire hydrant by an open nozzle thereof .
fooomy In association with the present invention, the following services are rendered:
1. Consultation with the client to identify the faulty pipe sections and determine the level of improvement needed.
2. Through monitoring, sampling and/or laboratory analysis, determine the exact nature of the problem.
3. Review test results and, aligned with client needs, implement all, or a combination of the following steps:
3.1. Inspect, manipulate and assess the fire hydrants, main valves and users' service lines related to the project area.
3.2. Perform leak detection and isolation tests on the pipe sections to be rehabilitated.
3.3. Clean users' service lines.
3.4. Pre-clean the pipe by using air, water and the chemical pre-cleaning solution.
3.5. Soften the deposits by using hot water, and/or a chemical cleaning solution.
3.6. Finalize the pipe cleaning by evacuating the softened and dislodged material.
r 4. Through monitoring, sampling and/or laboratory analysis, confirm the effectiveness of the rehabilitation.
BRIEF DESCRIPTION OF DRAWINGS
toooi8l A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
toooZS1 FIG. 1 is a block schematic diagram illustrating the method of cleaning a potable water distribution piping system in accordance with the present invention;
fooo2ol FIGS. 2 and 3 are schematic diagrams showing the process of blasting the incrusted sediments from the inner wall of a section of pipe being cleaned and using the method in accordance with the present invention;
toooxy FIG. 4 is a block schematic diagram showing a modification of the method as illustrated in Figure 1; and tooo22~ FIG. 5 is a block schematic diagram illustrating the method of cleaning the user lines associated with a main water conduit.
DESCRIPTION OF PREFERRED EMBODIMENTS
tooo231 The following procedure is undertaken to identify the faulty pipe sections and determine the level of improvement needed to a potable water distribution piping system. First, an evaluation and an assessment of the water distribution system are done to identify the pipe sections needing a non-structural rehabilitation. The evaluation includes the identification of pipes that have an appropriate metal thickness for a non-structural rehabilitation. The evaluation also consists in investigating the historic of leaks and breakages; the pipe material, diameter and age; the identification of sections that contribute to water quality complaints; the sections r that do not provide sufficient pressures and flows, the sections of the distribution system targeted for expansion;
the sections that are part of a rehabilitation master plan;
and the sections that show vulnerability in meeting water quality government regulations and insurance requirements pertaining to fire protection.
fooo24~ Samples are taken from the pipe sections to be cleaned for laboratory analysis. The pipe sections water samples may be kept, immediately after its collection in the field, and at all times, in a container filled with water to provide a similar condition as its day-to-day environment.
A chemical analysis of the deposits found in the pipe water samples is performed to analyze the incrusted sediments, the residual wall thickness, and the expected remaining service life.
Iooo2sl In the field, the C-Factor (roughness coefficient) of the pipe to be rehabilitated is measured using the Hazen-William coefficient as recommended by the American Water Works Association. The Hazen-Williams coefficient is the major loss calculation for the water in pipe using a friction loss equation. Another method for evaluating the pipe C-Factor is to analyze the pipes' characteristics based on the hydraulic model database.
Iooo2sl We also measure static and dynamic (residual) pressures and flow at each fire hydrant located in the project area to evaluate the true hydraulic performance of the distribution system.
toooa~~ Based on the results of the laboratory analysis, we determine the preferred water temperature, optimal chemical solution and soaking time period necessary to dissolve, dislodge and evacuate the deposits on the pipe inner wall to restore the pipe hydraulic carrying capacity during the cleaning and rehabilitation procedures. The analysis procedures may include the soaking of the pipe in t _ g _ the chosen solution and periodically observe the dissolution, softening and dislodging of the incrusted sediments. The observations are made at regular intervals at temperatures up to 180 degrees Fahrenheit for the duration of the soaking.
fooo2el Referring to Figure 1, there is shown the equipment used with the method of the present invention.
Before the start of the rehabilitation method, we inspect and perform water tightness test on the fire hydrants 15, 18, 25, 27, and 31 and the water main valves 14, 16, 17, 19, 26, 28, 29, and 32 that will be used to carry out the method. In addition, we inspect and manipulate all users' service lines 20 connected to the section of pipe 21 to be rehabilitated to confirm their proper operation. The defective fire hydrants, main valves and service lines must be repaired or replaced prior to the beginning of the rehabilitation work.
(00029) In addition to the above, we perform a leak detection test on the pipe section to be rehabilitated 21 and on the users' service lines 20 using an acoustic correlator. We also perform an isolation test on the pipe section to be rehabilitated by closing valves 17, 26, 28, and 29. To confirm the proper isolation of the pipe, we open fire hydrant 25. There should be no flow at the hydrant. If there is a flow, find and repair the defective valve(s).
fooo3o~ Cleaning of the pipe section 21 as shown in Figure 1 is a method or process using a combination of purified air, water, blasting material such as ice pellets, floatable plastic pellets, and/or any other material creating an abrasive effect, and/or a non-toxic chemical solution. The objective of the pre-cleaning is to remove the non-solidified deposits and other loose residues and sediments.
Iooo317 The method comprises closing the main valves 17, 26, 28 and 29 to isolate the pipe section to be rehabilitated 21. If necessary, the users' service lines 20 connected to the pipe sections to be rehabilitated are closed. In parallel to the valve closing operation, the air compressor 1 is connected to the fire hydrant 25 using a specially conceived hose 2 and adaptor. In addition, we hook up, to the other fire hydrant nozzle 25, a hose connected to a chemical container 22 and feed pump 23, and/or we connect the hose to a pellet container 24. This set up, based on the results of the sample laboratory tests, is used to inject the pellets and/or a non-toxic blend of surfactant and sequestering agent inside the water main.
tooo32~ The surfactant is used to penetrate the deposits 50 incrusted on the pipe wall 51, and contributes to dislodging and transporting the deposits and other residues to the exit fire hydrant 18, see Figures 2 and 3. In addition, the surfactant will promote back pressure useful to the generation of turbulences 53 and high sheer water velocities necessary to properly dislodge the scaling and hardened deposits 50. The sequestering agent softens the hard deposits and therefore helps to improve the effectiveness of the cleaning.
fooo331 Following the closing of the water main valves 17, 26, 28, and 29, fire hydrant 25 is opened. The pipe section 21 should still be filled with water. However, there should be no water flow coming out of fire hydrant 25. If not, all water main valves that were closed should be verified. It is preferable to proceed with repair if a valve is found not to be watertight.
(00034 Either valve 26, 28 or 29 are opened (valve 28 as shown in Figures 2 and 3) to create a minimal flow 55 between ten (10) gpm to fifty (50) gpm at fire hydrant 25.
Then, hydrant 18 is opened, and the air compressor 1 is turned on to inject the air under pressure inside the water pipe through the fire hydrant 25. The cubic feet per minute (CFM) is adjusted considering the pipe diameter and Hazen-Williams coefficient. Simultaneously, the chemical feed pump 23 is turned on to inject the chemical solution 22 inside the water pipe 21 through the fire hydrant 25.
fooo351 The water, mixed with the chemical solution, is then propelled inside the pipe by the compressed purified air, creating the compacted pockets 53 intermittently scrubbing on the pipe walls. Air purification is achieved by successive steps of cooling and filtering, as shown at 57 in Figure l, through multi-levels cartridge filters (not shown) in order to avoid oily contamination of the distribution system. Effective pre-cleaning is achieved when the adequate concentration of surfactant is added to the water. The chemical solution is fed in concentrations capable of generating the foam required to create the adequate back pressure. Optimum efficacy occurs when foam is produced.
foooss~ Pellets can also be used to dislodge the deposits if it is deemed necessary during the laboratory tests.
Pellets contained in the container 24 are introduced in the pipe through fire hydrant 25.
tooos7~ When foam reaches hydrant 18, the process is stopped to let the pipe section to soak for a time period determined during the sample laboratory test. The solution will then penetrate and soften the deposits 50. Following this soaking, the cleaning process is restarted for a period of time anywhere between five (5) to thirty (30) minutes based on laboratory tests results. Then, turn off the chemical feed pump 23.
(ooo3sl The pellets and/or the chemical solution are flushed away when there are no more pellets or foam showing at hydrant 18. The turbidity is measured periodically and we continue on with flushing until turbidity readings are back to near normal. Turbidity readings cannot be taken when foam and/or pellets are present in the water. Deposits removed from the surfaces contribute to the cleaning process as they become themselves abrasive material when mixed with the abrading pockets to blast away further deposits as they travel down the pipe. Velocities linked to the spinning of water pockets improve the blasting efficacy.
fooo3sl To complete the cleaning of pipe section 21, we use the same cleaning procedures in the opposite direction.
For example, hydrant 18 becomes the feed hydrant, and hydrant 25 becomes the exit hydrant. Reversing the procedure will ensure a uniform cleaning of the entire pipe length. Not surprisingly, pre-cleaning performance is better in the late section of the pipe. This is why the process is reversed to ensure a proper pre-cleaning of the entire pipe length.
fooo4o~ Adding pellets will enhance the removal of sediments and therefore contribute to reducing the soaking time needed for the rehabilitation. The cleaning operation is stopped when the turbidity readings are back to near normal.
fooo4i~ When applicable, water flushing is performed along the untreated pipe sections to flush out all the loose material that were not evacuated during the pre-cleaning.
For this example, the untreated pipe sections to be flushed are located between the water main valves 26, 28 and 29, and fire hydrant 25.
(00042 With reference now to Figure 4, there is shown the softening procedure which relies on the soaking with hot water, and/or a strong, non-toxic food grade cleaning solution to soften and break the first and hard layer of the incrusted deposits 50 found on the pipe inner wall. The other sediments, underneath the hard layer, are softer and easily removable during the hydro-mechanical cleaning phase of the procedures. The softening procedures are very similar to those described above. The major differences are that the cleaning chemical solution may be replaced with hot water, and/or with a strong, acidic chemical compound more capable of performing extensive removal of hard deposits.
This compound, added to the water, forms a very strong cleaning solution. The strong chemical cleaning solution may or may not be heated depending on the laboratory test results. Also based on laboratory test results, the soaking time of the strong chemical solution is determined to dislodge persistent deposits.
Iooo431 In addition to the equipment mentioned above, boiler 37 and associated apparatus 35, 36 and 37, is needed to allow the heating of the water and/or the strong cleaning solution. The main purpose for injecting heated liquids into a pipe is to heat the pipe material and therefore engender its expansion to splinter the sediments and provide easier access and penetration of the cleaning solution in the core of the sediments 50. As an example, the extension of a cast iron pipe is of .07 inch at every 100 feet of pipe for every l0 degrees Fahrenheit increase in pipe temperature.
fooo441 A fire hydrant 27 is selected that is not connected to the pipe section 21 to be cleaned. This fire hydrant will be used to supply the potable water necessary to feed the boiler device 37 used to heat the water. The device 37 must convey the hot liquid into a storage tank 36 using a specially conceived hose.
fooo451 As per the results of the sample laboratory tests, the water and/or the cleaning chemical solution is heated to a predetermined temperature. The hot liquid is then transferred into a watertight reservoir 36 specially conceived to store hot liquids . Once the appropriate volume of hot liquid has been poured in the storage tank, pump 35 feeds the hot liquid into the pipe section 21 through fire hydrant 25. The hot liquid slowly fills the pipe sections to be rehabilitated and will eventually come out of fire hydrant 18 as the pipe is entirely filled. We keep flushing the hot liquid at fire hydrant 18, and we monitor temperature, and close the gate valve at the hose nozzle 18' of fire hydrant 18 when the proper temperature has been reached, as determined during the laboratory tests.
X000461 If a chemical solution is used for soaking instead of hot water, the spent solution will be transferred into a tank 40 and neutralized with an alkaline material in order to safely be disposed of in the sewer system. A very small portion of liquid from the pipe section is emptied to allow a stop-and-go movement of the hot liquid. Air is injected intermittently using the compressor at fire hydrant 25 to intensify the movement of the hot liquid in the pipe. This will harmonize the liquid temperature on the entire pipe length. The hot liquid is left to soak in the pipe for a time period as determined during the laboratory tests.
fooo4~~ Following the soaking, the procedure as described above is repeated to clean the pipe and the hot water and/or strong cleaning chemical solution are evacuated along with the dissolved materials. If a chemical solution is used for soaking instead of hot water, the spent solution will be transferred into a tank 40 and neutralized with an alkaline material in order to safely be disposed of in the sewer system.
fooo4a~ Following the rehabilitation and all the steps as described above, the pipe section is disinfected using the ANSI/AWWA C651-99 standards by the American Water Works Association (AWWA).
fooo4s) Following the cleaning of the pipe section 21 and to ensure that the rehabilitation objectives have been met, the following field tests and measurements are performed:
the Hazen-Williams coefficient measurement; the leak detection using acoustic correlator; the static and dynamic pressures on the fire hydrants 18 and 25 that are included in the method are measured and also on those surrounding the project area, and the standard water quality tests including turbidity and residual chlorine are performed. The purpose of those tests is to review the hydraulic and water quality results following the pipe rehabilitation, and to confirm the level of improvement and effectiveness of the method.
fooo5ol Referring to Figure 5, there will now be described the method of cleaning the user's service lines 20 to provide full benefits related to the rehabilitation of the water main. For the service line 20, outfitted with a water meter 11, the valve 5 must be closed upstream from the meter before disconnecting the service line. The line is cut and with a hose 2, the air compressor 1 is connected thereto with a connector suitable for the type and the size of the service line 20. The hose must be equipped with a ball valve. Then, the service line valve 5 must be re-opened.
Iooosi~ For the service line not outfitted with a meter, the valve 3, located inside the building 12, must first be closed. The service line 20 must be disconnected downstream of the valve 3. The service line 20 is cut and with a hose 2 it is connected to the air compressor 1 with a connector suitable for the type and the size of the service line 20.
The hose must be equipped with a ball valve. During the installation, the exterior valve 5 remains opened.
fooos2~ When the installation of the equipment is completed, the water main valve 10, located downstream of the fire hydrant 8, must be closed to prevent the spreading of the sediments throughout the entire distribution system.
It is preferable to flush the sediments in the same course as the normal direction of flow 6 in the main pipe section 7. The procedure is not necessary if the water main is a dead end. When the valve 10 is closed, fire hydrant 8 must be fully opened. Following the opening of the fire hydrant 8, the air compressor 1 must be turned on to push the sediments down the line and the water main pipe. The compressor must deliver the proper cubic feet per minute (CFM) air pressure to ensure the removal and evacuation of all sediments incrusted inside the service line 4.
Iooos3l During the cleaning of the service line, the flushed water 9 from the hydrant 8 should be colored and the turbidity very high. It is important to flush the hydrant 8 until the water reaches a turbidity level of 10 Neophelometric Turbidity Unit (NTU) or less. As above-mentioned, this is a measurement of the cloudiness of water due to suspended particles in the water (clay, silt, rust, etc). Lower is the reading, clearer is the water. When the turbidity level is at 10 NTU or less, the air compressor 1 can be turned off. The main water valve 10 is reopened and the air compressor 1 is disconnected from the service line 20 and the water meter 11 is reconnected. The re-connection of the service line to the water main is performed to standards. Open and flush a water tap inside the building for at least five (5) minutes and proceed with water quality tests to ensure the safe use of the water.
fooos4~ It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein provided such modifications fall within the scope of the appended claims.
Claims (26)
1. A method of cleaning and/or rehabilitating a potable or a non-potable water distribution piping system comprising the steps:
i) identifying a section of pipe to be cleaned of deposited sediments incrusted on an inner wall thereof, and two fire hydrants connected to said section of pipe to define a flow path through said section of pipe to be cleaned, ii) identifying all valves connected to said section of pipe and in the vicinity of said two fire hydrants, iii) connecting an air compressor to a hydrant nozzle of one of said two fire hydrants upstream of a cleaning water flow to be generated, iv) connecting a reservoir containing a sediment dislodging product to a second hydrant nozzle of said one fire hydrant, v) opening one of said valves connected in the vicinity of said one fire hydrant upstream of a connection thereof with said section of pipe to be cleaned whereby to create a minimal water flow therefrom into said section of pipe to be cleaned upstream of said cleaning water flow to be generated, vi) opening a hydrant nozzle of the other of said two fire hydrants downstream of said cleaning water flow to be generated, vii) operating said compressor to inject air under pressure inside said section of pipe to be cleaned through said one of said fire hydrants and simultaneously injecting said sediment dislodging product into said section of pipe to be cleaned through said one of said fire hydrants, viii) creating spinning water pockets inside said section of pipe to be cleaned by said air under pressure mixed with said sediment dislodging product and said minimal water flow admitted through said opened valve of step (v) whereby to blast said deposited sediments in said section of pipe to be cleaned, and ix) flushing said water and dislodged sediments through said hydrant nozzle of the other of said two fire hydrants.
i) identifying a section of pipe to be cleaned of deposited sediments incrusted on an inner wall thereof, and two fire hydrants connected to said section of pipe to define a flow path through said section of pipe to be cleaned, ii) identifying all valves connected to said section of pipe and in the vicinity of said two fire hydrants, iii) connecting an air compressor to a hydrant nozzle of one of said two fire hydrants upstream of a cleaning water flow to be generated, iv) connecting a reservoir containing a sediment dislodging product to a second hydrant nozzle of said one fire hydrant, v) opening one of said valves connected in the vicinity of said one fire hydrant upstream of a connection thereof with said section of pipe to be cleaned whereby to create a minimal water flow therefrom into said section of pipe to be cleaned upstream of said cleaning water flow to be generated, vi) opening a hydrant nozzle of the other of said two fire hydrants downstream of said cleaning water flow to be generated, vii) operating said compressor to inject air under pressure inside said section of pipe to be cleaned through said one of said fire hydrants and simultaneously injecting said sediment dislodging product into said section of pipe to be cleaned through said one of said fire hydrants, viii) creating spinning water pockets inside said section of pipe to be cleaned by said air under pressure mixed with said sediment dislodging product and said minimal water flow admitted through said opened valve of step (v) whereby to blast said deposited sediments in said section of pipe to be cleaned, and ix) flushing said water and dislodged sediments through said hydrant nozzle of the other of said two fire hydrants.
2. A method as claimed in claim 1 wherein said step (iv) comprises connecting a chemical reservoir and feed pump to said second hydrant nozzle, said chemical reservoir containing a non-toxic blend of surfactant and sequestering agent constituting said sediments dislodging products.
3. A method as claimed in claim 2 wherein said surfactant penetrates said deposited sediments incrusted on said inner wall of said pipe section to be cleaned for dislodging at least some of said deposited sediments and promoting back pressure due to foaming to generate turbulences and high sheer water velocity to dislodge said deposited sediments.
4. A method as claimed in claim 3 wherein said sequestering agent softens hard deposits to improve cleaning efficiency.
5. A method as claimed in claim 2 wherein said step (iv) further comprises injecting impacting particles together with said non-toxic blend to create an abrasive effect on said deposited sediments incrusted on said inner wall.
6. A method as claimed in claim 1 wherein said step (iv) comprises connecting a reservoir having impacting particles therein constituting said sediments dislodging products.
7. A method as claimed in claim 6 wherein said impacting particles are one of ice pellets, floatable plastic pellets, and other suitable recoverable pellets.
8. A method as claimed in claim 1 wherein said minimal water flow step (v) is in the range of from about 10 gpm to about 50 gpm.
9. A method as claimed in claim 1 wherein after step (vi) there is provided the step of verifying all said valves identified in step (ii) and repairing any of said valves that are not watertight.
10. A method as claimed in claim 1 wherein said injected air in step (vii) is purified air, said purified air being obtained by cooling and filtering ambient air through multi-level cartridge filters.
11. A method as claimed in claim 3 wherein said surfactant will foam in said pipe section to be cleaned, and wherein said step (ix) further comprises closing said hydrant nozzle of said other of said two fire hydrants after said foam is detected to permit said surfactant to soak into said deposited sediments for a predetermined period of time to penetrate and soften said deposited sediments.
12. A method as claimed in claim 11 wherein after said soaking of said surfactant said hydrant nozzle of said other of said two fire hydrants is opened for a predetermined period of time to flush out said dislodged sediments.
13. A method as claimed in claim 12 wherein said predetermined periods of time for said soaking and flushing are determined based on laboratory tests of pipe samples taken from said section of pipe to be cleaned.
14. A method as claimed in claim 12 wherein after said surfactant foam is monitored during said flushing and when said foam is no longer present there is provided the further step of measuring turbidity periodically until a normal turbidity reading of about 20 NTU or less is obtained indicating that said hydrant nozzle of said other of said two fire hydrants can be closed.
15. A method as claimed in claim 1 wherein after step (ix) there is provided the steps: (x) of monitoring water quality of said flushed water until a normal turbidity reading is obtained, (xi) closing said hydrant nozzle of said other of said two fire hydrants, and (xii) reversing the connections of some of said steps to change the direction of said water flow to clean said pipe section from said other of said two fire hydrants to said one of said two fire hydrants to ensure proper cleaning of said entire section of pipe to be cleaned.
16. A method as claimed in claim 1 wherein said step (iv) comprises connecting a reservoir of hot water to said second hydrant nozzle of said one fire hydrant for soaking said deposited sediments incrusted on said inner wall of said section of pipe to be cleaned whereby to soften and break an outer layer of said deposited sediments.
17. A method as claimed in claim 16 wherein there is further provided the steps of locating a third fire hydrant outside said section of pipe isolated by step (ii), feeding water from said third fire hydrant to a boiler to obtain said hot water.
18. A method as claimed in claim 17 wherein there is further provided the step of adding a strong non-toxic chemical compound to said hot water in said reservoir to form a strong cleaning solution.
19. A method as claimed in claim 16 wherein said step (ix) comprises flushing hot water with said strong cleaning solution and dislodged sediment in a holding tank for neutralizing same with an alkaline material for safe disposal in a sewer system.
20. A method as claimed in claim 16 wherein there is further provided with step (ix) of monitoring the temperature of said flushed hot water, and closing said hydrant nozzle of the other of said two fire hydrants when a predetermined temperature of about 180°F is detected to completely fill the section of pipe to be cleaned, and soaking said deposited sediments incrusted on said inner wall of said section of pipe to be cleaned whereby to cause said section of pipe to expand and splinter said deposited incrusted sediments to cause said hot water to penetrate into said incrusted sediments, said section of pipe being a metal section of pipe.
21. A method as claimed in claim 20 wherein there is further provided the step of opening said hydrant nozzle of said other of said two fire hydrants to remove a small portion of said hot water whereby to disturb said hot water soaking in said section of pipe, and injecting said air under pressure in an intermittent manner to intensify said disturbance and harmonize said water temperature along said section of pipe to soften deposited incrusted sediments, and flushing said softened sediments by injecting air under pressure in accordance with step (vii).
22. A method as claimed in claim 20 wherein there is further provided the step of disinfecting said section of pipe using the ANSI/AWWA 0651-99 standards of the AWWA, and effecting other field tests to confirm the level of improvement and effectiveness of said method.
23. A method as claimed in claim 13 wherein said laboratory tests comprise the step of performing a chemical analysis of said deposited sediments formed in said pipe samples to determine the composition of said incrusted sediments.
24. A method as claimed in claim 23 wherein said laboratory tests also provide for the step of evaluating residual wall thickness of said section pipe and expected remaining service life.
25. A method as claimed in claim 24 wherein there is further provided the step of measuring the C-Factor of said section of pipe and the static and dynamic pressure of water flowing therethrough.
26. A method as claimed in claim 1 wherein there is further provided the step of cleaning the service lines connected to said section of pipe, said service lines being connected to said section of pipe through a respective one of said valves of step (ii), said service lines being cleaned by the steps of:
(a) closing one of said fire hydrants downstream of normal water flow through said section of pipe, (b) disconnecting said service line from an entrance to a user facility, (c) connecting an air compressor at said disconnection, (d) opening a hydrant nozzle of a fire hydrant between said service line and said closed fire hydrant, (e) actuating said air compressor to evacuate sediments from said service line into the flow of water in said section of pipe being evacuated through said opened hydrant nozzle, (f) measuring the turbidity of said water evacuated through said opened hydrant nozzle, (g) de-actuating said compressor and reconnecting said service line after a desired turbidity reading is obtained, and closing said hydrant nozzle, and (h) opening said fire hydrant of step (a).
(a) closing one of said fire hydrants downstream of normal water flow through said section of pipe, (b) disconnecting said service line from an entrance to a user facility, (c) connecting an air compressor at said disconnection, (d) opening a hydrant nozzle of a fire hydrant between said service line and said closed fire hydrant, (e) actuating said air compressor to evacuate sediments from said service line into the flow of water in said section of pipe being evacuated through said opened hydrant nozzle, (f) measuring the turbidity of said water evacuated through said opened hydrant nozzle, (g) de-actuating said compressor and reconnecting said service line after a desired turbidity reading is obtained, and closing said hydrant nozzle, and (h) opening said fire hydrant of step (a).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2500048 CA2500048A1 (en) | 2005-03-08 | 2005-03-08 | Method of cleaning a potable water distribution piping system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2500048 CA2500048A1 (en) | 2005-03-08 | 2005-03-08 | Method of cleaning a potable water distribution piping system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2500048A1 true CA2500048A1 (en) | 2006-09-08 |
Family
ID=36955295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2500048 Abandoned CA2500048A1 (en) | 2005-03-08 | 2005-03-08 | Method of cleaning a potable water distribution piping system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2500048A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016079730A1 (en) * | 2014-11-17 | 2016-05-26 | Ohayon Yehoshua | System and method for flushing and cleaning air conditioning system |
| WO2021044166A1 (en) * | 2019-09-05 | 2021-03-11 | ATAM Group Limited | A method for cleaning the inside of pipework |
-
2005
- 2005-03-08 CA CA 2500048 patent/CA2500048A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016079730A1 (en) * | 2014-11-17 | 2016-05-26 | Ohayon Yehoshua | System and method for flushing and cleaning air conditioning system |
| WO2021044166A1 (en) * | 2019-09-05 | 2021-03-11 | ATAM Group Limited | A method for cleaning the inside of pipework |
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