GB2398802A

GB2398802A - Flow control apparatus, system and method

Info

Publication number: GB2398802A
Application number: GB0304694A
Authority: GB
Inventors: Jeffrey Peter Farrow
Original assignee: Thames Water Utilities Ltd
Current assignee: Thames Water Utilities Ltd
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2004-09-01
Also published as: GB0304694D0

Abstract

According to the invention there is provided apparatus for controlling surcharge in a liquid flow system, such as a sewer, the apparatus comprising a chamber 103 through which liquid can flow, means 104 defining with the chamber an inlet chamber part 105 and an outlet chamber part 106, and a device 107 operable to respond to a surcharge and control liquid flow from the inlet to the outlet chamber part whereby to seek to prevent a liquid surcharge. Also defined is a method for controlling surcharge in a liquid flow system, comprising a system with means to determine the onset of surcharge in a system. The method also involves providing a means to attenuate flow surcharge, to prevent flooding from the system.

Description

FLOW CONTROL APPARATUS, SYSTEM AND METHOD The invention relates to a flow

control apparatus, system and method, and particularly to sewerage systems.

Sewerage systems are typically used to carry sewage away from a dwelling to a remote location for treatment. Dwellings are often situated in a street or road, which provides the course for a main sewer, to which each dwelling is connected by a branch pipe or sewage outlet.

Some of the dwellings may be situated in positions susceptible to flooding, particularly if sewage backs up in the system. Normally, under non-exceptional conditions, the sewer has a capacity sufficient to manage all the sewage entering it. However, in certain circumstances, such as in a flash rainstorm, the volume of liquid is such that the sewer starts to back up and flow is reversed so that flooding can occur in one or more of the dwellings, for example in their basements or gardens. This is undesirable to say the least, and as the sewer comes under pressure during such surcharge conditions, can damage the sewer.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to a first aspect of the invention there is apparatus for controlling surcharge in a liquid flow system, comprising a chamber through which liquid can flow, means defining with the chamber an inlet chamber part and an outlet chamber part, and a device operable to respond to a surcharge and control liquid flow from the inlet to the outlet chamber part whereby to seek to obviate a liquid surcharge.

Using the invention it is possible to provide controlled management of new and existing sewerage networks.

The inlet chamber part and the outlet chamber part may be internally of the chamber.

This provides for ease of construction and a relatively small "footprint" for the apparatus.

The means defining the chamber parts may comprise an interior wall of the chamber, preferably the wall may extend substantially the height of the chamber, and may include means to allow liquid flow between the inlet and outlet part. This provides a particularly efficient construction.

The means may comprise a valve member.

There may also be a pump for pumping liquid from the inlet to the outlet part.

The device operable to respond to a surcharge may comprise a level detector which on detecting a surcharge is adapted to actuate the valve member for controlling flow between the inlet and outlet parts of the chamber whereby to seek to obviate a liquid surcharge.

The level detector device may comprise an ultrasonic device or some other suitable means of level detection. This provides an efficient level detection means.

The chamber may comprise a plurality of inlet parts, each with its own valve member, level detector and pump.

In a preferred embodiment there may be two inlet parts, defined by a wall extending from a boundary of the chamber to the first-mentioned wall. This provides a particularly simple construction.

The apparatus may be retro-fitted in an existing manhole. This provides for relatively simple up-dating of an existing sewerage system.

According to a second aspect of the invention there is provided a liquid flow system such as a sewerage system, comprising a sewer, and at least one apparatus as hereinbefore defined.

There may be a plurality of manholes spaced apart along a sewer connected to areas liable to flood in surcharge conditions, and there may be control means for the apparatus of an upstream manhole in an immediately downstream manhole.

There may be additional control devices in manholes upstream of the apparatus.

According to a third aspect of the invention there is provided a method of controlling surcharge in a liquid flow system, comprising providing a system, providing means to determine onset of surcharge in the system, and providing means to attenuate a flow surcharge whereby to seek to obviate flooding from the system.

The step of providing means to determine onset of surcharge may comprise a sensor means of the system.

The step of providing means to attenuate a flow surcharge may comprise apparatus including a chamber for receiving liquid and holding same temporarily.

The apparatus may be upstream of the sensor means.

An apparatus, system and method embodying the invention are hereinafter described, by way of example, with reference to the accompanying drawings.

Fig. 1 is a plan view of one embodiment of apparatus according to the invention; Fig. 2 is a plan view of a second embodiment of apparatus according to the invention; Fig. 3 is a schematic diagram of part of a first sewerage system, incorporating apparatus according to Fig. 1; Fig. 4 is a schematic diagram of a second sewerage system, incorporating apparatus according to Fig. 2; Figs. 5 to 10 show conditions in a sewerage system of a typical street, without apparatus according to the invention; Figs. 11 to 15 show sewage management and surcharge control in the street of Figs. 5 to 10, when apparatus according to the invention is utilised; Figs. 16 to 18 show respectively a plan view and perspective views of the apparatus of Fig. l in use.

Referring to the drawings in which like parts are referred to by like reference numerals, there is shown apparatus l DO, 200 for controlling a surcharge in a liquid flow system, such as a sewerage system lot, 102 comprising a chamber 102 through which liquid such as sewage can flow, means 104 defining with the chamber 103 an inlet chamber part 105 and an outlet chamber part 106, and a device 107 operable to respond to a surcharge and control liquid flow from the inlet 105 to the outlet chamber part 106 whereby to seek to obviate a sewage surcharge.

The chamber 103 is generally a right cylinder, and as shown in Fig. 1, and 16 to 18, the inlet chamber part 105 and outlet chamber part 106 are situated interiorly of the chamber 103, being defined by the means 104 in the form of a substantially vertical wall which extends to the top of the chamber 103, the inlet chamber 105 having in the embodiment about twice the volume of the outlet chamber part 106.

There is a valve member 108 in the wall 104 which is operable to control flow of sewage from the inlet to the outlet chamber part.

The device is a sewage level detector in the outlet chamber part 106 and in the embodiment is an ultrasonic level detector device, to detect sewage levels in the outlet chamber part 106.

There is in the inlet chamber part 105, a pump 109, in the embodiment a low-head submersible pump, for pumping sewage from the inlet chamber part 105 to the outlet chamber part 106 via pumps 1 10.

The valve member 108 is essentially a penstock kind of device.

Fig. 2 shows a second embodiment of apparatus 200 in which there are two inlet chamber parts 105, defined by a wall 1 1 1 orthogonally arranged with respect to the wall 104, so that there are two wall parts each with a valve member or penstock 108 and each inlet chamber part having a pump, again each one being a low-head submersible pump.

A schematic arrangement of the apparatus of Figs. 1 and 2 is shown respectively in Figs. 3 and 4, where A, B. C and D denote an existing manhole, the apparatus 100 of Figs. 1, 2 being a manhole A respectively, in Fig. 3 there being a single sewer 101 and t in Fig. 4 there being two sewers 101 feeding to a single main sewer 112 via the apparatus, each respective inlet chamber part being fed via one or more sewerage pipes.

In each embodiment, the apparatus 100, 200 is a pre-fabricated unit with an open top, and a base, which base is shaped to form "benching" i.e. such that normal sewage flow will be directed through the normally-open valve member or penstock 108 from the inlet chamber part 105 to the outlet chamber part 106 to the downstream part of the sewage pipe 101. The inlet chamber part 105 mounts, in addition to the pump 109 which is submersible, a level sensor such as a float valve for actuation of the pump, and controls.

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In use, as shown in Figs. 3 and 4, the apparatus is located in the next manhole A upstream of a property at risk of flooding F. A main control sensor is located in the next manhole B downstream of properties (dwellings) at risk of flooding. Further level sensors will be located as necessary or desired in upstream manholes (C) and (D), i.e. above or upstream of the apparatus.

Turning now to Figs. 5 to 15, there is shown a typical street S. with properties (dwellings) connected to the main sewer 101. There are manholes A, B. C, spaced apart along the sewer and houses 6 and 14 are for this description taken to lie in low areas as compared to the other houses 2, 4, 8, 10 and 12 and are therefore at risk of flooding (Fig. 5). Under normal sewage flow (Fig. 6), there is no surcharge, and therefore no problem, or risk of flooding.

Referring now to Fig. 7, as there is an excess of surface water from rain R. flow in the sewerage system 101 increases, and pipes downstream of 'a' cannot cope with the volume and begin to back-up. There is no surcharge problem as such at this juncture, but sewage flow from right to left as viewed in the Fig. is becoming restricted, with a resultant beginning of a surcharge in manhole 'A'. Sewage pipes for manholes A - C are shown ata, b,c end d.

On continued flow of excess water, the sewerage system (a) downstream of manhole A becomes surcharged, with the result that sewage level rises in manhole A, and pipe 'b' of the network begins to surcharge. The pipe connection to house 6 then begins to back-up (Fig. 8). This results in manholes A and B both being surcharged, and the garden of house No. 6 begins to flood, as the hydraulic level in pipe 'b' is greater than an inspection chamber level in that garden (Fig. 9).

If the excess water "storm" conditions continue, sewer pipes 'c' and 'd' will back-up and the garden of low-lying house 14 may begin to experience sewer flooding too (Fig. 10).

Figs. 11 - 15 show the same street, with apparatus embodying the invention in manhole A. Fig. 11 is similar to Figs. 5 and 6 i.e. normal flow, no problems.

In Fig. 12, rainwater causes flow in the sewerage system to increase, and pipes 'a' cannot cope, similar to Fig. 7, i.e. surcharge begins in the manhole 'A'.

In Fig. 13 the ultrasonic detector 107 set to 'trigger' at a particular level of the sewage in the outlet chamber part 106, identifies that the surcharge has risen to trigger level; initially open valve member 108 is automatically closed, the sewage level in the inlet chamber part 105 remaining low.

In Fig. 14, the pump 109 has also been actuated, to pump sewage in apparatus 100 from the inlet chamber part 108 to the outlet chamber part 106, to maintain upstream surcharge to a minimum, though there is an increasing flooding risk to the upstream dwellings, while there is yet no flooding in garden 6.

As the excess "storm" water condition continues, a further (upstream) level detector in manhole 'C' identifies "trigger" level in the apparatus in manhole 'C' providing an early warning that the garden of No. 14 may flood. A second apparatus 100 can be included in manhole 'C' to obviate this flooding.

Apparatus embodying the invention and shown in the drawings can be a prefabricated unit, fitted into a new or modified manhole. It has a fullheight division wall, between inlet and outlet, with an actuated penstock (normally open). There is a level detector (suitably ultra-sonic) at the top of the outlet chamber at 'X'. The level detector will identify any surcharge as the level rises in the outlet chamber part.

The trigger level is set at a height so that the penstock closes well before the garden to No. 6 is at risk. With the penstock closed, the outlet chamber can become surcharged without affecting he level in the inlet chamber. The inlet chamber will begin to back- up as the incoming flow now has no outlet.

The pump in the inlet chamber now switches to pump through to the outlet. The apparatus can now allow a gravity discharge from its outlet which will remain (harmlessly) surcharged until the downstream level dissipates.

The low-head pump will keep the inlet chamber at a safe level to protect house No. 6 from flooding, for as long as possible.

A sewerage system utilising the apparatus can be a standard installation which includes at least one, and possibly more, ultrasonic level detectors to trigger closing of penstocks etc. Pumps may be started and stopped on simple float controls, and level detectors which are remote from the apparatus location, need to communicate either by hard wire laid through the sewer or by using a wireless technology network.

The overall system can also continuously log flow levels and transmit back to a central computer, perhaps once per day, in order to improve knowledge of actual flow conditions, and daily 'transmission' can also include details of plant condition etc.

Claims

1. Apparatus for controlling surcharge in a liquid flow system, comprising a chamber through which liquid can flow, means defining with the chamber an inlet chamber part and an outlet chamber part, and a device operable to respond to a surcharge and control liquid flow from the inlet to the outlet chamber part whereby to seek to obviate a liquid surcharge.

2. Apparatus according to Claim 1, the inlet chamber part and the outlet chamber part being internally of the chamber.

Apparatus according to Claim 1 or Claim 2, the means defining the chamber parts comprising an interior wall of the chamber.

4. Apparatus according to Claim 3, the wall extending substantially the height of the chamber, and including means to allow liquid flow between the inlet and outlet part.

5. Apparatus according to Claim 4, the means comprising a valve member.

6. Apparatus according to Claim 5, comprising a pump for pumping liquid from the inlet to the outlet part.

7. Apparatus according to Claim 6, the device operable to respond to a surcharge comprising a level detector which on detecting a surcharge is adapted to actuate the valve member for controlling flow between the inlet and outlet parts of the chamber whereby to seek to obviate a liquid surcharge. lo

8. Apparatus according to Claim 7, the level detector device comprising an ultrasonic device.

9. Apparatus according to Claim 7 or Claim 8, the chamber comprising a plurality of inlet parts, each with its own valve member, level detector, and pump.

10. Apparatus according to Claim 9, there being two inlet parts, defined by a wall extending from a boundary of the chamber to the first-mentioned wall.

11. Apparatus for controlling surcharge in a liquid flow system, substantially as hereinbefore described with reference to the accompanying drawings.

12. Apparatus according to any preceding claim, retro-fitted in an existing manhole.

13. A liquid flow system such as a sewerage system, comprising a sewer, and at least one apparatus according to any preceding claim.

14. A system according to Claim 13, there being a plurality of manholes spaced apart along a sewer connected to areas liable to flood in surcharge conditions, there being control means for the apparatus of an upstream manhole in an immediately downstream manhole.

15. A system according to Claim 14, there being additional control devices in manholes upstream of the apparatus.

16. A sewage flow control system, substantially as hereinbefore described with reference to the accompanying drawings. ll

17. A method of controlling surcharge in a liquid flow system, comprising providing a system, providing means to determine onset of surcharge in the system, and providing a means to attenuate flow surcharge whereby to seek to obviate flooding from the system.

18. A method according to Claim 17, the step of providing means to determine onset of surcharge comprising a sensor means of the system.

19. A method according to Claim 18, the step of providing means to attenuate a flow surcharge comprising apparatus including a chamber for receiving liquid and holding same temporarily.

20. A method according to Claim 19, the apparatus being upstream of the sensor means.

21. A method according to Claim 17, substantially as hereinbefore described.