WO2002020909A1

WO2002020909A1 - Liquid reservoir, pumping device for it, and method of emptying the liquid reservoir

Info

Publication number: WO2002020909A1
Application number: PCT/NL2001/000591
Authority: WO
Inventors: Jacobus Eldert Maria Van Baar
Original assignee: Intelligent Environmental Systems B.V.
Priority date: 2000-08-07
Filing date: 2001-08-06
Publication date: 2002-03-14
Also published as: EP1307620B1; AU2001294344A1; DK1307620T3; NL1015884C2; EP1307620A1

Abstract

The invention relates to a liquid reservoir, comprising a container having an inlet for free inflow of liquid into the container, an outlet having a valve for forced discharge of liquid from the container, and a pump which presses by means of gas pressure, in particular air pressure to cause the forced discharge of the liquid. A pumping housing is accommodated in the container, to which the pressure side of the pump and the outlet is connected and which communicates with the container through an inlet valve of the housing. This liquid reservoir is well suited for use as sewer drain for collecting and discharging sewage. The invention further includes a pumping device and a method of emptying the liquid reservoir.

Description

LIQUID RESERVOIR, PUMPING DEVICE FOR IT, AND METHOD OF EMPTYING THE LIQUID RESERVOIR

The present invention relates to a liquid reservoir comprising a cistern with a inlet for a free inflow of liquid into the cistern, an outlet fitted with a valve for a forced discharge of liquid from the cistern, and a pump which forces by means of gas pressure, in particular air pressure, to realise said forded discharge of the liquid. Such a liquid reservoir in the form of a catch pit is known from GB-A-i 379 566,

The object of the invention is to further improve such a liquid reservoir. in order to accomplish that objective, the liquid reservoir according to the invention is characterised in that a pump housing is accommodated in the reservoir, to which housing the delivery side of the pump as well as said outlet are connected, and which is in communication with the cistern via an inlet valve of the housing.

The liquid reservoir according to the invention has the advantage that the housing can form an independent unit within the cistern. In the case of a catch pit being used as a liquid reservoir, the housing, in addition to being used in new catch pits, can also function as a unit which is subsequently built into an existing cistern of the catch pit. In that case an existing catch pit fitted with an electromechanical submersible pump can for example be converted into a catch pit according to the invention, wherein the water is pumped by means of gas pressure. Thus a great many applications of the liquid reservoir according to the invention are possible .

An improved filling of the space within the housing can be achieved if the pump is a vacuum pressure pump having a suction side and a delivery side, which are both connected to the housing, whereas the pump is arranged for alternately drawing gas into the housing and forcing gas out of the housing.

Furthermore it is advantageous if the pump is disposed outside the cistern of the liquid reservoir and is connected to the housing via at least one conduit, such as a hose. The advantage of this construction is that the pump is readily accessible, which makes it possible to carry out maintenance work and repairs on the pump in a simple manner, whereas furthermore the pump is not exposed to the liquid that is present in the cistern of the liquid reservoir and is possibly corrosive.

The invention furthermore relates to a pumping device for use in a liquid reservoir, for example the above-described liquid reservoir, whereas the invention also relates to a method for emptying a liquid reservoir. The invention will now be explained in more detail with reference to the drawing, which very schematically shows an exemplary embodiment of the catch pit according to the invention.

Pig. l is a very schematic vertical sectional view of the exemplary embodiment of the catch pit according to the invention- Figs. 2, 3 and 4 are vertical sectional views of the pump housing of the catch pit according to Fig. l, showing three different stages thereof when the catch pit is being drained.

Fig. 1 shows a catch pit which is incorporated in a sewer system, in which sewage water from one or more sources can collect. The catch pit includes a cistern l, which may be made o concrete, for example, and which will usually be disposed underground. Cistern l comprises an inlet 2 for letting in sewage water, which flows into the cistern 1 of the catch pit via a natural drop. Cistern 1 furthermore includes an outlet 3, which is located at a low level in the catch pit and which is led to a higher level via an outlet pipe 4 fitted with an outlet valve 5, and which exits the cistern at said higher level. connected to outlet 3, at the bottom end of outlet pipe 4, is a coupling, to which the outlet of a pump housing 6 is connected. Said pump housing 6 forms part of a pumping device, which, in addition to pump housing 6, comprises a vacuum pressure pump 7 and one or more connecting hoses 8 between pump 7 and housing 6. As already said before, said housing includes an outlet 9, which is connected to the coupling of outlet 3. Housing 6 furthermore includes an inlet 10, which is in communication with the cistern l of the catch pit and which can be closed by means of an inlet valve 11, in this embodiment in the form of a non- eturn valve, which is mounted in the interior of housing 6 and which closes inlet 10 when the pressure in housing 6 is larger than the pressure in cistern l. Valve n opens automatically when the pressure in cistern l is sufficiently higher than the pressure in housing 6. Present in the upper wall of housing 6 is the pump connection 12 to which the connecting hose 8 of pump 7 is connected. Pump 7 is ou&eά in a control box 13, which control box

13 is disposed at a higher level than cistern l, in particular above ground level, so that the interior of the control box 13 is readily accessible from outside. The control box comprises the control units which are required for the functioning of catch pit 1. Thus, a level sensor 15, which is disposed in cistern 1 of the catch pit, is connected to control unit 14, in response to the signals from which sensor the control unit 14 can control pump 7.

Vacuum pressure pump 7 is so arranged that it can alternately function as a vacuum pump and as a pressure pump, to which end hose 8 is switched between the suction side and the delivery side of the pump. In the suction position, air is drawn from the interior of housing 6 , and consequently a sub-atmospheric pressure will be generated in housing 6 , which makes it possible for housing 6 to be completely filled with sewage water. In the pressure position, air is pumped into housing 6 via hose 8 for the forced discharge of sewage water from housing 6.

Figs. 2 , 3 and 4 illustrate the operation of the pumping device in the catch pit according to Fig. 1.

In Fig. 2, pump housing 6 is in the inoperative position, When pump connection 12 is connected to the suction side of vacuum pressure pump 7 via connecting hose 8, as shown in Pig. 3, a sub- tmospheric pressure will be generated in housing 6 and non-return valve 11 will open, as a result of which water from cistern 1 of the catch pit will fill the interior of the housing completely or to a large extent. Housing 6 may have partially filled with sewage water previously already, which sewage water had entered the housing due to the water pressure in the pit. Once the housing is filled to a sufficient degree, vacuum pressure pump 7 will be reversed and the connecting hose 8 will be placed in communication with the pressure side of the pump 7, as a result of which air is pumped into housing 6 from the pump 7 and the sewage water that is present in the housing will be placed under pressure. Non-return valve 11 will close, as a result of which inlet 10 will be closed, so that the sewage water cannot flow back to cistern 1. When outlet valve s is opened either automatically or in response to a control signal, the sewage water from housing 6 will be forced upwards through outlet pipe 4 via outlet 3, thus exiting cistern l, from where the sewage water can be further discharged. Pump 1 will continue to operate until housing 6 has been emptied, after which pump housing 6 is ready for a new cycle. From the foregoing it will be apparent that the invention provides a liquid reservoir and a pump therefor which are remarkable for their universal applicability, as well as for the simplicity of construction and reliable operation, because the pump is disposed outside cistern 1, so as to enable easy access thereto, in a protected environment, with only the housing being accommodated in the cistern of the pit. The pumping device is very suitable for use in existing catch pits, where it can replace the electromechanical submersible pumps that are used therein. The connections of the housing can be configured such that the existing pump can simply be disconnected and the housing can be fitted instead.

In addition to being used in catch pits, the invention can also be used in all kinds of other liquid reservoirs for collecting in particular corrosive liquids, such as liquids in the refinery industry, developers and waste water from various production processes.

The invention is not restricted to the exemplary embodiment as described above and shown in the drawing, which can be varied in several ways without departing from the scope of the invention. Thus, the pump may be configured as a pressure pump only, in which case the housing will be filled as a result of the pressure from the water in cistern 1. Furthermore, the pump may also be mounted on the housing. Also further variations are conceivable, of course.

Claims

1. A liquid reservoir comprising a cistern (1) including an inlet (2) for a free inflow of liquid into the cistern, an outlet (3) fitted with a valve (5) for a forced discharge of liquid from the cistern, and a pump (7) which forces by means of gas pressure, in particular air pressure, to realise said forced discharge of the liquid, characterized in that a pump housing (6) is accommodated in the cistern (l) , to which housing the delivery side of the pump (7) as well as said outlet (3) are connected, and which housing is in. communication with the cistern via an inlet valve (11) of the housing (6) .

2. A liquid reservoir according to claim 1 or 2, wherein the pump (7) is a vacuum pressure pump having a suction side and a delivery side, which can both be connected to the housing ( 6) , whereas the pump is arranged for alternately drawing gas into the housing and forcing gas out of the housing,

3. A liquid reservoir according to claim 1 or , wherein the housing (6) is a unit which is adapted for being built into an existing cistern (1) of the liquid reservoir.

4. A liquid reservoir according to any one of the preceding claims, wherein the pump (7) is disposed outside the cistern (1) of the liquid reservoir and said pump is connected to the housing (6) via at least one conduit, such as a hose (8) .

5. A liquid reservoir according to a.ny one of the preceding claims, wherein the liquid reservoir includes a separate control box (13) , which is positioned at a higher level than the cistern (1) and in which the pump (7) is housed.

6. A liquid reservoir according to any one of the preceding claims, wherein the inlet valve (11) of the housing (€) is a non- eturn valve.

7. A liquid reservoir according to any one of the preceding claims, wherein the liquid reservoir is in the form of a catch pit for collecting and discharging sewage water.

8. A pumping device for use in a liquid reservoir according to any one of the preceding claims, comprising a pressure pump (7) which forces by means of gas pressure, in particular air pressure, for the purpose of realising said forced discharge of the liquid, as well as a housing (6) to be accommodated in said liquid reservoir, which housing includes a connection for the pressure side of the pump as well as an outlet (9) to be connected to an outlet of the liquid reservoir for discharging liquid from the housing, and which furthermore includes an inlet (10) , in which a valve (11) is mounted, for communication with the liquid reservoir, which communication can be shut off, which inlet functions to allow liquid to flow into the housing from the liquid reservoir.

9. A pumping device according to claim 8, wherein the pressure pump (7) is connected to the housing (6) by means of a conduit, such as a hose (8) .

10. A method for emptying a liquid reservoir, wherein a housing disposed in a cistern of the liquid reservoir, which includes an associated pump, is used for alternately allowing liquid to flow from said cistern into the housing and subsequently forcing said liquid out of the housing by means of gas pressure from said pump, via an outlet connected to the housing, whereas the communication between the housing and the liquid reservoir is shut off at that moment.

11. A method according to claim 10, wherein a suction side of the pump, in this case in the form of a vacuum pressure pump, is placed into communication with the housing for the purpose of allowing liquid to flow into the housing.

12. A method according to claim 9 or 10 to be used in emptying a catch pit.