AU674561B2

AU674561B2 - A method and a device for automatic circulation in a waste water pump station

Info

Publication number: AU674561B2
Application number: AU57893/94A
Authority: AU
Inventors: Bengt Sodergard
Original assignee: ITT Flygt AB
Current assignee: Xylem Water Solutions AB
Priority date: 1993-04-29
Filing date: 1994-03-17
Publication date: 1997-01-02
Anticipated expiration: 2014-03-17
Also published as: EP0623713B1; DE69419562T2; DE69419562D1; CA2122087A1; SE9301459D0; JP2607839B2; AU5789394A; EP0623713A1; DK0623713T3; SE501192C2; CA2122087C; JPH0776873A; NO941463L; SE9301459L; NO941463D0

Description

~~1 A METHOD AND A DEVICE FOR AUTOMATIC CIRCULATION IN A WASTE WATER PUMP STATION The invention concerns a device for providing circulation in pump stations which are parts of a municipal sewage system.

As is described in the Swedish Patent Application 7908743-3 sludge banks occur in pump stations and other tanks in a sewage system as the circulation is not good enough. Sludge banks mean a lot of problems such as a bad smell, risk for explosions, corrosion problems etc.

According to the Patent Application mentioned, the problems have been solved by arranging a valve in the pump outlet, which is opened temporarily thus obtaining a circulation and flushing in the pump station. The sludge banks are dissolved and the fluid is homogenized.

The adjustment of the valve has up to now been controlled by electric means by help of a linear motor which acts upon a slide in the valve. A disadvantage with this solution, in addition to a relatively high cost, is that it easily becomes clogged as the *pumped medium normally contains large amounts of solid bodies such as stones, rags and other objects. If a stone is stuck in the valve slide, the electric motor may break down.

Aohrdsdvnaei ht SAnother disadvantage is that t'1e motor of the valve is electrically driven which means specific installation problems whers explosive gas may occur.

Another way to solve the problem to control the valve by help of the pump pressure is shown in Swedish Pat No 8900597-9. Here the under pressure created by the flow through the valve is utilized to move a valve element into a closed position after a certain time. This solution has however the disadvantage that the under pressure is not always sufficiently strong to be able to move the clement into closed position.

It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

There is disclosed herein a method for controlling a valve for obtaining circulation in a sewage water pump station containing one or several pump units at least one of which is provided with a said valve, which automatically, during predetermined limited time period(s) connects the pressure side of a said pump with said pump station, thus obtaining a circulation of the pumped medium, said control method comprising: closing said valve by movement of a movable valve element from a first rest position associated with a first diaphragm located outside flow through said valve, to a.

second rest position wherein said valve element seals against a seat in a valve housing of said valve, thereby closing said valve, preventing flow from said valve housing to an outlet part of said valve, wherein said movement of said valve element is achieved by movement of said first diaphragm resulting from a pressure differential between said outlet pat and said valve Lousing, caused by flow through said valve, and influence of flow on said valve element once said first diaphragm movement has positioned said valve element in proximity of said flow, and opening said valve by movement of said movable valve element from said second rest position to said first rest position, wherein said movement is achieved by gravity force acting on said movable valve element.

There is further disclosed herein a valve for obtaining circulation in a sewage water pump station containing one or more pump units, said valve comprising a valve housing and an outlet part, said valve housing being provided with a first diaphragm and said outlet part being provided with a second diaphragm, said first and second diaphragms being adapted to delimit rooms which are communicated by a conduit and 25 to respond to a pressure differential between said outlet part and said valve housing caused by flow through said valve, a resultant movement of said first diaphragm tending to move a valve element in a closing direction towards a seat in said valve housing, thus interrupting flow therethrough.

"A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: .Fig 1 shows a pump station with a pump unit and attached valve. Figs 2 to 4 show the principle design of the valve in different operating positions.

In the drawings 1 stands for a pump station with a submersible pump unit 2 connected to a pressure pipe 3. 4 stands for the pump housing having an inlet 5, while 6 stands for a mixing valve mounted on the pump housing 4. 7 stands for a valve housing and 8 its outlet with a bend 9. 10 stands for a valve ball and 11 its seat. 12 and 13 stand for diaphragms, 14 and 15 cups, 16 a conduit, 17 a control device and 18 a shoulder in the outlet.

The device operates in the following manner: Normally the valve 6 is closed and the pumped medium is transported from the pump housing 4 and into the pressure pipe 3. The flow direction is shown by the Arrow A.

IN:\LIBLL0OO353:JCC During certain times, for instance at pump start, the valve is open, which means that a certain amount of the pumped medium flows through the valve, arrow B, and obtains a strong agitation in the pump station wrecking possible sludge barn's.

After a certain time, the valve is closed and the pumping takes place in the normal way.

According to a preferred embodiment the valve 6 comprises a valve housing 7 with an outlet 8 ended by a bend 9. Within the valve housing 7 a valve cup 14 is provided which holds a diaphragm 12 with a valve ball 10. This is arranged to be able to close the passage through the valve housing 7 when it rests on a seat 11.

In Fig 2 the valve is shown in open position which means that .SeeS.

*o a• eo' IN:\LIBLL100353:JCC 3 circulation takes place within the pump station. The valve ball ,then takes a position entirely beside the flow, not hindering it.

The flow through the valve now creates pressure differences which may be used for controlling the valve function. Depending on among r other things that the cross section in the outlet 8 is smaller than the cross section in the valve housing 7, the pressure in the former will be higher. The difference may also be increased by a shou±der 18 or a bend 9 in the outlet which further increases the pressure.

1o The mentioned pressure difference is utilized by arranging rooms in the valve housing 7 and the outlet 8 which are delimited by diaphragms 12 and 13 respective, said rooms being connected by a conduit 16.

0* The pressure difference between the inner of the valve housing 7 i' and the outlet 8 when there is a flow through the valve, causes the diaphragm 13 to be pressed inwards which means that the medium, oil, within the rooms is pressed through the conduit 16 towards the room delimited by the diaphragm 12. The latter will then be pressed outwards, upwards in the drawing, and act upon the ball 10 in a closing direction, (Fig When the ball has been moved a distance upwards, it will be influenced by the flow which brings it to a sealing alignment with the seat 11.

The time it takes for the oil to move from the room delimited by the diaphragm 13 to the room delimited by the diaphragm 12 is s controlled in a suitable way by help of a restriction in the con- S duit 16.

In Fig 4 the valve is shown in a closed position which is the case after a predetermined time. Pump pressure will now prevail within the valve housing 7 as long as the pump operates. This means that the diaphragm 12 is pressed downwards to its original position and the oil is pressed back towards the diaphragm 13 which is not influenced by the pump pressure and thus resumes its original, bending design. When the pumping stops the pressure decreases and the valve ball 10 is moved by gravity to its original position. The ?s valve is then open waiting for next pump start.

1_ 4 In the description above a loose valve ball is used which seals against a seat in order to close the valve. Also other movable possibly turnable elements may be used as closing means and are within the scope of the invention.

In the description and especially in the drawings it is stated that the valve ball is actuated upon by a diaphragm 12 which has a corresponding number 13 in the outlet 8. The rooms being delimited by the diaphragms communicating via a conduct 16. It should be stressed that the drawings just show a preferred embodiment. The io design of the diaphragms as well as that of the rooms may vary within the scope of the invention, to utilize the pressure difference between two different parts in the valve.

*oe S6DG-12.EHG

Claims

1. A method for controlling a valve for obtaining circulation in a sewage water pump station containing one or several pump units at least one of which is provided with a said valve, which automatically, during predetermined limited time period(s) connects the pressure side of a said pump with said pump station, thus obtaining a circulation of the pumped medium, said control method comprising: closing said valve by movement of a movable valve element from a first rest position associated with a first diaphragm located outside flow through said valve, to a second rest position wherein said valve element seals against a seat in a valve housing of said valve, thereby closing said valve, preventing flow from said valve housing to an outlet part of said valve, wherein said movement of said valve element is achieved by movement of said first diaphragm resulting from a pressure differential between said outlet part and said valve housing, caused by flow through said valve, and influence of flow on said valve element once said first diaphragm movement has positioned said valve element in proximity of said flow, and opening said valve by movement of said movable valve element from said second rest position to said first rest position, wherein said movement is achieved by gravity force acting on said movable valve element.

2. The method of claim 1, characterised in that said pressure differential between said outlet part and said valve housing acts upon said first diaphragm and a second diaphragm located within said outle, art, said first and second diaphragms delimiting communicating rooms. S3. A valve for obtaining circulation in a sewage water pump station o containing one or more pump units, said valve comprising a valve housing and an outlet 25 part, said valve housing being provided with a first diaphragm and said outlet part being provided with a second diaphragm, said first and second diaphragms being adapted to delimit rooms which are communicated by a conduit and to respond to a :l pressure differential between said outlet part and said valve housing caused by flow through said valve, a resultant movement of said first diaphragm tending to move a 30 valve element in a closing direction towards a seat in said valve housing, thus interrupting flow therethrough.

Sa

4. The valve of claim 3, further provided with a controlling device adapted to control flow through said conduit, which determines a closing time for said S "valve.

5. The valve of claim 3 or 4, wherein said outlet part is provided with an interior shoulder which is adapted to increase said pressure differential.

6. The valve of any of claims 3 to 5, wherein said outlet part is terminated by a bend which directs flow from said valve and also adds to said pressure differential.

7. A pump unit provided with the valve of any of claims 3 to 6, wherein R AZ 4 said pump unit is a centrifugal pump of the submersible type. I(N:\LILL00OO353:JCC 6

8. A method to control a valve for obtaining circulation in a sewage water pump station containing one or more pump units, substantially as hereinbefore described with reference to the accompanying drawings.

9. A valve for obtaining circulation in a sewage water pump station containing one or more pump units, substantially as hereinbefore described with reference to the accompanying drawings. Dated 31 July, 1996 ITT Flygt AB Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON *i 0 0 *o e oo A Method and a Device for Automatic Circulation in a Waste Water Pump Station ABSTRACT The invention concerns a method and a device for obtaining automatic circulation in waste water pump stations On the pressure side the pump unit is provided with a valve which during certain periods opens a connection between the pump unit and the pump station thus obtaining a circulation in the latter. The valve is opened and closed by a valve ball (10) which is controlled by the pump pressure. Figure 1 1128M/CMS o* e 0* I*28/ M