WO2002079095A1

WO2002079095A1 - Cleaning of off-set lamps in ultraviolet light water treatment system

Info

Publication number: WO2002079095A1
Application number: PCT/CA2002/000376
Authority: WO
Inventors: Demao Wang
Original assignee: Photoscience Japan Corporation
Priority date: 2001-03-28
Filing date: 2002-03-20
Publication date: 2002-10-10
Also published as: JP2005504620A

Abstract

A water treatment apparatus comprising a fluid-flow passageway (17) therein for flow of water to be treated, with a first (10) and second (18) elongated ultraviolet lamp assembly extending across the passageway in a spaced-apart location and off-set orientation. The water treatment apparatus has a lamp assembly cleaning device that simultaneously cleans the off-set first and second elongated ultraviolet lamp assemblies. In particular, the passageway forms part of a pipe (40) reactor for treatment of water. In preferred embodiments of said lamp assembly cleaning device, each elongated ultraviolet lamp assembly (16, 18) has at least two annular cleaning units (78A, 79A, 78B, 79B) in a spaced-apart relationship. Each annular cleaning unit encloses an elongated ultraviolet lamp assembly in cleaning contact. Each of the cleaning units has a guide mechanism attached thereto, with all of the guide mechanisms being attached to a common frame (60). The common frame is movable from a first position to a second position whereby the guide mechanism moves in said frame and the cleaning units effect cleaning of the elongated ultraviolet lamp assembly.

Description

CLEANING OF OFF-SET LAMPS IN ULTRAVIOLET LIGHT WATER TREATMENT SYSTEM

FIELD OF THE INVENTION The apparatus of the present invention relates to an ultraviolet lamp assembly, especially an ultraviolet lamp assembly for the treatment of water, in which each lamp is at an off-set angle with respect to the adjacent lamp. In particular, the present invention relates to apparatus for the cleaning of such off-set lamps. In particular embodiments of the present invention, the off-set lamps are located in a pipe or other enclosed apparatus for the treatment of water. It is understood that the apparatus could have a variety of cross-sectional shapes, including being circular, rectangular or square.

BACKGROUND TO THE INVENTION

Ultraviolet water treatment systems typically have a plurality of elongated ultraviolet lamp assemblies, in which the ultraviolet lamps are immersed in or extend into the water that is to be treated. The water is caused to flow past the ultraviolet lamps. The lamps are enclosed in quartz tubes, especially quartz tubes with one closed end.

An ultraviolet system that is specifically designed for disinfecting water must be capable of performing with the maximum of reliability and the minimum amount of so-called "down time" for repairs and maintenance, especially including cleaning of the quartz sleeves. Moreover, because these ultraviolet treatment systems are primarily used for municipal drinking water projects, it is necessary that the system have a minimum capital requirement and minimum operating costs.

Ultraviolet lamps typically operate with surface temperatures that are anywhere in the range from about 40°C to 800°C, depending upon the type of lamp. The only thing that is between the lamp and the water is the protective quartz sleeve. Depending on the source of the water, the water may contain calcium, manganese, iron and other compounds, which tend to precipitate out on the surface on the quartz sleeve. The quartz sleeve thus tends to become opaque, and the ultraviolet light generated by the lamp is unable to reach the water to kill any microorganisms that are in the water. From time to time, it becomes necessary to clean the quartz sleeve(s). This may be accomplished by disassembly of the water treatment apparatus, which usually involves significant down time or the use of a cleaning system that can be operated while the ultraviolet water treatment system is still functioning. In embodiments, the ultraviolet water treatment system is in the form of an open channel in which racks of elongated ultraviolet lamp assemblies are placed. These racks of ultraviolet lamps have the lamps in a parallel relationship, which are capable of being cleaned by using brushes, scrapers and other devices that can be moved from one end of the ultraviolet lamp to the other while the lamp is in operation. Depending on the quality of the water, such cleaning may be effected on a daily or more frequent basis. The trend in the ultraviolet water treatment industry is to use ultraviolet lamps that are located in pipe-shaped reactors with the lamps oriented perpendicular to the flow of water through the reactor. This creates a very compact ultraviolet water treatment system. The lamps in the pipe-shaped reactors are normally placed in a parallel aligned relationship i.e. the lamps are aligned to form a row of parallel elongated lamps longitudinally in the reactor. A disadvantage of such an arrangement of lamps is that the lamps in the middle of the array will have a portion of their ultraviolet light absorbed by the adjacent ultraviolet lamp. It is possible to off-set the lamps so that the lamps are not arranged in a parallel arrangement i.e. so that each lamp is at an angle to the adjacent lamps. This reduces overlap of the lamps, and thus reduces the absorption of ultraviolet light by the adjacent lamp.

If the lamps in a pipe-shaped reactor are arranged in parallel, a cleaning mechanism similar to that used for an array of lamps in an open channel may be used i.e. multiple lamps may be cleaned at the same time by moving the cleaning apparatus from one end to the other of the array of parallel lamps. However, if the lamps are in an off-set arrangement, it becomes necessary to clean each lamp on an individual basis, which increases the cost of the apparatus. It would be useful and more economic to be able to clean more than one elongated lamp in an assembly of lamps in which the lamps are at an off-set angle to the adjacent lamp.

SUMMARY OF THE INVENTION ^~ A cleaning unit that is capable of simultaneously cleaning at least two adjacent lamps that are at off-set angles has now been found.

Accordingly, one aspect of the present invention provides a water treatment apparatus comprising a fluid-flow passageway therein for flow of water to be treated, a first and second elongated ultraviolet lamp assembly extending across said passageway in a spaced-apart location and off-set orientation, said water treatment apparatus having a lamp assembly cleaning device that simultaneously cleans said first and second elongated ultraviolet lamp assemblies.

In a preferred embodiment, the passageway forms part of a pipe reactor for treatment of water, especially in which the passageway is in a housing.

In further embodiments, the passageway has a cross-sectional shape selected from the group consisting of circular, rectangular and square. In a particularly preferred embodiment, in said lamp assembly cleaning device, each elongated ultraviolet lamp assembly has at least one annular cleaning unit and preferably two in a spaced-apart relationship, each annular cleaning unit enclosing an elongated ultraviolet lamp assembly in cleaning contact, each of said cleaning units having a guide mechanism attached thereto, all of said guide mechanisms being attached to a common frame, said common frame being moveable from a first position to a second position whereby said guide mechanism moves in said frame and said cleaning units effect cleaning of the elongated ultraviolet lamp assembly.

In another embodiment, the cleaning unit is a brush, scraper or chemical cleaning system.

In a further embodiment, there are two cleaning units on each ultraviolet lamp assembly, said cleaning units being on opposed sides of said guide mechanism.

In a still further embodiment, the guide mechanism is selected from the group consisting of bearings, rollers and wheels.

In further embodiments, the frame is attached to a drive mechanism, especially in which the drive mechanism is a lead screw thread.

Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples while indicating embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from said detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by the embodiment shown in the drawings, in which:

Figure 1 is a schematic representation of a pipe reactor with off- set ultraviolet lamp assemblies;

Figure 2 is a schematic representation of a pipe reactor with offset ultraviolet lamp assemblies, with a lamp assembly cleaning device in a first position;

Figure 3 is a schematic representation of the pipe reactor of Figure 2, with the lamp assembly in a second position;

Figure 4 is a schematic representation of a top view of the pipe reactor of Figure 2;

Figure 5 is an isometric view of an embodiment of a lamp assembly cleaning device in a pipe reactor; and Figure 6 is an isometric view of the frame of a lamp assembly cleaning device.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a water treatment apparatus having a fluid-flow passageway through which water to be treated is passed. Elongated ultraviolet lamp assemblies extend across the passageway, with adjacent lamp assemblies being at off-set angles. The apparatus has a lamp assembly cleaning device that is capable of simultaneously cleaning adjacent lamp assemblies. The fluid-flow passageway could be any passageway that water may pass through and be treated. In the passageway, each elongate ultraviolet lamp assembly is at an off-set angle to the adjacent elongated ultraviolet lamp assembly. The passageway could be in the form of an open channel or other passageway, but it is particularly preferred that the passageway be through a housing, especially a housing of a pipe- type reactor for the treatment of water. The present invention will be particularly described herein with respect to the latter type of reactor.

Figure 1 shows a schematic representation of a pipe reactor 10 with off-set ultraviolet lamp assemblies. Pipe reactor 10 has flange 12 with a plurality of bolt holes 14. Flange 12 is used to connect pipe reactor 10 to the remainder of the piping system of the water treatment apparatus.

First elongated ultraviolet lamp assembly 16 extends across fluid- flow passageway 17 that passes through pipe reactor 10. Similarly, second elongated ultraviolet lamp assembly 18 extends across fluid-flow passageway 17, but at an off-set angle to first elongated ultraviolet lamp assembly 16. In the embodiment shown in Figure 1 , first elongated ultraviolet lamp assembly 16 is perpendicular to second elongated ultraviolet lamp assembly 18. However, it is to be understood that the lamp assemblies could be off-set at different angles, with the overlap of ultraviolet light from the lamps being minimal in the embodiment shown in Figure 1.

First elongated ultraviolet lamp assembly 16 extends from upper bushing 20 in pipe wall 19 across fluid-flow passageway 17 to lower bushing 24 in pipe wall 19. First elongated ultraviolet lamp assembly 16 has electrical connections 22 that connect to a ballast, (not shown), as is known in the art. Similarly, second elongated ultraviolet lamp assembly 18 extends from upper bushing 26 in pipe wall 19 across fluid-flow passageway 17 to lower end bushing 30 in pipe wall 19. Electrical connection 28 extends from second elongated ultraviolet lamp assembly 18 to a ballast (not shown).

In Figure 1 , it is understood that the lamps of the elongated ultraviolet lamp assemblies are enclosed in quartz sleeves, which are shown as being closed at one end. It is the sleeves that are located in the bushings, the lamp being within the quartz sleeve. Figure 2 shows a cross-section of the pipe reactor as shown in Figure 1 , but with a lamp assembly cleaning device of the present invention located on the first and second elongated ultraviolet lamp assemblies. The pipe reactor, indicated by 40, has a housing 42 that is attached to pipe wall 19 by means of housing attachment 43. Housing 42 encloses motor 44 of the lamp assembly cleaning device. Motor 44 has gear box 46, which is located on base plate 48. Gear box 46 is connected by split coupling 50 to shaft 52. Shaft 52 passes through gland 54 and mechanical seal 56, as well as shaft collar 58, all of which serve to connect motor 44 to lead screw thread 64, and to seal pipe wall 19 so that water in fluid-flow passageway 17 does not leak out of pipe reactor 40. Lead screw thread 64 extends downwards across fluid-flow passageway 17 and is connected to pipe wall 19 by means of brushing cap 66 and bearing 68. Lead screw thread 64 forms the shaft of the cleaning device. Thus, lead screw shaft 64 extends across fluid-flow passageway 17 into bearing 68. It is understood that the lead screw thread could be replaced by other linear motions devices.

Lead screw thread 64 has frame 60 thereon. Frame 60 is shown as being of square construction, which is the preferred shape of frame 60. Frame 60 has bushings 62 at the opposed locations where lead screw thread 64 passes through frame 60. Bushing 62 is attached to frame 60 and to lead screw thread 64 at the opposed locations. Frame 60 also has transverse frame brace 76, which is attached to the other opposed corners of frame 60 and located with respect to lead screw thread 64 by bushing 70. Thus, in preferred embodiments, the cleaning device shaft is a lead screw thread and bushing 70 is correspondingly threaded.

Each of first elongated ultraviolet lamp assembly 16 and second elongated ultraviolet lamp assembly 18 has a pair of scrapers, identified as first scrapers 78A-D and second scrapers 79A-D. In particular, first elongated ultraviolet lamp assembly 16 has first scraper 78A and second scraper 79A located on opposed sides of one section of frame 60 and first scraper 78B and second scraper 79B on the opposed side of frame 60. Similarly, second elongated ultraviolet lamp assembly 18 has first .scraper 78C and second scraper 79C located on opposed sides of one section of frame 60 and first scraper 78D and second scraper 79D located on the opposed side of frame 60. Thus, each of the opposed sides of frame 60 has a pair of scapers viz. first scraper 78 and second scraper 79 on opposed sides of the particular section of frame 60. Each of first scraper 78A-78D and second scraper 79A-79D has a pair of wheels that are in rolling contact with frame 60.

In addition to motor 44, housing 42 encloses proximity sensors 72, which is located on sensor bracket 74. Proximity sensor 72 is used in determining the location of frame 60 within fluid-flow passageway 17. The invention is particularly described herein with respect to the cleaning device having scrapers. It is understood that the scrapers could be replaced with other types of cleaning units, including brushes and chemical cleaning systems. Examples of the latter are described in US Patents 5418 370 and 5 590 390, both of J.M. Maarschalkerweerd, and US Patent 5 874 740 of E. Ishiyama.

Figure 3 shows the embodiment of the pipe reactor of Figure 2 in which the lamp assembly cleaning device has been moved, as in the cleaning of the first elongated ultraviolet lamp assembly 16 and the second elongated ultraviolet lamp assembly 18. Frame 60 is now located closer to motor 44, and thus further away from bearing 68. The locations of the first scraper 78 and second scraper 79 have moved on the respective elongated ultraviolet lamp assemblies. At the same time, the wheels 90 have moved on frame 60 as is described below with respect to the operation of the lamp assembly cleaning device. Figure 4 shows a top view of the apparatus of Figure 2, with housing 42 omitted for clarity. Pipe reactor 40 has pipe wall 19 that extends between flanges 12, indicated by 12A and 12B. Motor 44 is located on base plate 48 on pipe wall 19. Housing attachment 43 is located on pipe wall 19 to sections on opposed sides of pipe reactor 40. - Motor 44 is located between first elongated ultraviolet lamp assembly 16 and second elongated ultraviolet lamp assembly 18. Although not shown in Figure 4, frame 60 in fluid-flow passageway 17 would extend from lead screw thread 64 to the first and second elongated ultraviolet lamp assemblies, which are on opposite sides of lead screw thread 64.

In operation, motor 44 causes lead screw thread 64 to rotate. The rotation of lead screw thread 64 in bushings 70 causes frame 60 to move up or down along lead screw thread 64. Figure 3 shows that frame 60 has moved upwards, as illustrated, compared to the view shown in Figure 2. As frame 60 is moved, wheels 90 move along frame 60 in a cooperative manner, so that first scraper 78 and second scraper 79 move along their respective elongated ultraviolet lamp assemblies. The.net result is that the scrapers move along the length of the elongated ultraviolet lamp assemblies, and effect cleaning of those lamp assemblies. The frame is moveable from a first position e.g. the top, to a second position e.g. the bottom, or to any other position e.g. intermediate positions.

Figure 5 shows an isometric view of a lamp assembly cleaning device in water treatment apparatus. The apparatus, generally indicated by 100, has pipe wall 119 that forms fluid-flow passageway 117. Pipe wall 119 extends between flange 112A and flange 112B, which have bolt holes 114A and 114B respectively. Fluid-flow passageway 117 is annular i.e. it has a circular cross-section. However, the fluid-flow passageway may have other cross-sectional shapes, including rectangular and square.

Apparatus 100 has two elongated ultraviolet lamp assemblies, 116 and 118, that extend across fluid-flow passageway 117, as described previously.

Base plate 148, on which the motor (not shown) is located, extends upwardly from wall 119. Shaft 152 extends through wall 119, and forms lead screw thread 164. Frame 160 is located on lead screw thread 164, at bushings 162. Frame 160 is square in shape. Transverse frame brace 176 extends across frame 160, being connected to bushing 170 on lead screw thread 164. Each side 200 of frame 160 has a first scraper 178 and a second scraper 179 that are on opposed sides of side 200 of frame 160. Elongated ultraviolet lamp assembly 116 (or 118) extends through elongated slot 202 in side 200. Intermediate between first scraper 178 and second scraper 179 are bearings 180. Bearings 180 contact side 200, and enable the elongated ultraviolet lamp assembly to move in elongated slot 202.

Figure 6 shows an isometric view of frame 160. Transverse frame brace 176 is shown with orifices 170A of bushing 170. Similarly, orifices 162A for bushings 162 are shown.

The apparatus of the present invention permits the simultaneous cleaning of off-set lamps in an ultraviolet lamp assembly. The lamp assembly cleaning device may be operated automatically at any time, without the need to cease the treatment of water and/or disassemble the apparatus for cleaning. Thus, the lamp assembly cleaning device could be operated continuously, or preferably operated on an intermittent basis as required to maintain the lamp assemblies in a clean condition.

Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention.

Claims

CLAIMS:

1. A water treatment apparatus comprising a fluid-flow passageway therein for flow of water to be treated, a first and second elongated ultraviolet lamp assembly extending across said passageway in a spaced-apart location and off-set orientation, said water treatment apparatus having a lamp assembly cleaning device that simultaneously cleans said first and second elongated ultraviolet lamp assemblies.

2. The water treatment apparatus of Claim 1 in which the passageway forms part of a pipe reactor for treatment of water.

3. The water treatment apparatus of Claim 2 in which the passageway is in a housing.

4. The water treatment apparatus of Claim 3 in which the passageway has a cross-sectional shape selected from the group consisting of circular, rectangular and square.

5. ^"~ The water treatment apparatus of Claim 3 in which, in said lamp assembly cleaning device, each elongated ultraviolet lamp assembly has at least one annular cleaning unit in a spaced-apart relationship, each annular cleaning unit enclosing an elongated ultraviolet lamp assembly in cleaning contact, each of said cleaning units having a guide mechanism attached thereto, all of said guide mechanisms being attached to a common frame, said common frame being movable from a first position to a second position whereby said guide mechanism moves in said frame and said cleaning units effect cleaning of the elongated ultraviolet lamp assembly.

6. The water treatment apparatus of Claim 5 in which there are two annular cleaning units on each elongated ultraviolet lamp assembly.

7. The water treatment apparatus of Claim 5 in which the frame is movable to further positions.

8. The water treatment apparatus of Claim 5 in which the cleaning unit is a brush, scraper or chemical cleaning system.

9. The water treatment apparatus of Claim 7 in which there are two cleaning units on each ultraviolet lamp assembly, said cleaning units being on opposed sides of said guide mechanism.

10. The water treatment apparatus of Claim 9 in which the guide mechanism is selected from the group consisting of bearings, rollers and wheels.

11. The water treatment apparatus of Claim 10 in which the frame is attached to a drive mechanism.

12. The water treatment apparatus of Claim 11 in which the drive mechanism is a lead screw thread or other linear motion device.