FI122641B - Method and apparatus for rinsing a pump - Google Patents

Description

Method and device for flushing the pump

The present invention relates to a method according to the preamble of claim 1 for cleaning the housing of a pump, in particular a domestic water batch purification pump.

According to such a method, liquid is passed through the pump housing to remove any solid which has accumulated therein.

The invention also relates to a pump arrangement according to the preamble of claim 9.

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Batch purifiers use pumps that operate in a liquid and solid environment. Particularly in the pump casing, solids collect easily, which can be detrimental to the functioning of the device and the solids are generally not wanted to be carried away from the pump. This is the case, for example, when purified water is removed from the batch treatment plant 15. The solids pump also pumps out the solids when it is started. Especially at low pumping rates, this solid inside the pump significantly increases the amount of impurities.

Pump solutions based on compressed air have been developed to avoid problems. These are described, for example, in EP-A-1,566,498 and DE-Utility Model 20,105,661. In EP-A-1,566,598, the solid collected in the pipeline is removed from the pipeline by pumping it with compressed air back into the waste water separation chamber.

JP 2004351400 and JP 20001271782 disclose pumps for continuously separating water from a slurry containing solids. However, these solutions are cm expensive, complicated and difficult to apply to a batch purifier.

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The object of the present invention is to eliminate the problems of the prior art and

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to provide a completely new solution, in particular for purifying the batch purifier drain pump o 30 during use.

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The invention is based on the idea that the drain pump housing is flushed with an aqueous suspension passed through it, obtained from a purge tank acting as a buffer.

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Before rinsing, the rinse tank is then filled by pumping an aqueous suspension through a drain pump to remove at least a portion of the solids contained therein. Preferably, the volume of the aqueous suspension to be pumped into the container is at least equal, preferably greater than the volume of the drain pump housing.

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The invention also provides a batch purifier drain pump assembly comprising a pump having an outlet tube connected to a batch purifier process tank, wherein the aqueous suspension from the process tank can be discharged from the batch purifier via a pump outlet tube. According to the invention, the flushing tank is arranged above the pump 10 and has an outlet pipe and an inlet pipe, the latter of which is connected to the pump outlet pipe. The reservoir acts as a drain buffer and has a volume at least equal to the volume of the drain pump, so that the volume of liquid corresponding to the entire volume of the pump casing can be pumped into the reservoir through the pump outlet and the reservoir inlet.

More specifically, the method according to the invention is characterized in what is stated in the characterizing part of claim 1.

The pump assembly according to the invention, in turn, is characterized by what is stated in the characterizing part of claim 9.

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The invention provides significant advantages. Thus, with the solution shown, the pump can be flushed at necessary intervals. The solids inside the pump are effectively removed, thus preventing the solids from entering the purified water.

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25 In the following, the invention will be explored in greater detail by means of a detailed description with reference to the accompanying drawings.

Fig. 1 is a side view of the principle x structure of a batch effluent treatment plant;

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Figures 2a and 2b show the structure of a pump assembly with a flushing tank, o Figure 30 is a perspective view of the solution and Figure 2b a side view o partially broken away.

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As stated above, in the solution of the invention, the batch purifier drain pump housing is cleaned by regular back flushing. Flushing 3 can be used to ensure that no harmful amounts of solids accumulate in the pump, which would be removed with the liquid when the pump is started.

The above procedure may be performed once or repeated several times until the pump housing is substantially free of solids. Subsequently, the batch treatment plant can be dewatered through a flushing tank without the removal of solids from the pump housing.

The pump may be flushed at regular intervals during operation, with suitable flushing intervals 10 varying according to utilization rate. In practice, flushing the batch purifier pump 1 to 5 times daily or less frequently is sufficient.

The rinsing tank, preferably located above the pump, is pumped almost completely at a pulse rate so that the rinsing vessel also receives the solid in the pump housing, after which the liquid / solid mixture is allowed to drain gravitatively back through the pump, thereby flushing the pump housing.

The rinse operation is performed as required. Generally, the pumping pulses are from about 0.1 to about 20 seconds, preferably from about 0.5 to about 10 seconds, most preferably from about 1 to about 3 to 20 seconds. The stroke length depends on the pump output and the vessel volume! The rinsing period between pumping pulses is at least 10 seconds, preferably about 15 seconds to 5 minutes, and most preferably at least 1 minute. It is important that the flushing cycle is long enough for the solids to leave the pump.

c \ j o 25 The flushing tank is a conical or otherwise sloping bottom which is associated with the removal of the pump cm. Preferably, the tip of the conical bottom is connected to the outlet pipe of the drain pump i c, whereby the aqueous suspension pumped into the flushing tank is easily discharged by gravity x back into the pump and flushed through the housing.

□ _ 00 o 30 The flushing tank is dimensioned, for example, to accommodate 1 to 3 times the volume of the pump, effectively flushing the solids inside the pump.

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On the other hand, it is preferable that the tank is not so large in volume that filling and back flushing mix the clarified sludge in the process tank. Thus, in general, the volume of the flushing tank is about 1 to 10 times, especially about 1 to 5 times the volume of the pump.

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When using the treatment plant, the purged water from the process tank is regularly discharged from the purge tank via an outlet pipe. To make the above rinsing function possible, the water flow or outlet of the rinse tank is preferably located at the top of the tank 5, below the level at which the pumped aqueous suspension rises during pumping pulses to rinse the pump.

The cone base may be of the same material as the flushing container. Preferably, the material is such that the solid does not adhere to its surface. Suitable materials include 10 different thermoplastics and structural materials coated with them. Their surface can still be separately treated to improve non-tack. Examples of suitable plastics include polyethylene and polypropylene and other polyolefins.

The accompanying drawings illustrate a preferred embodiment of the invention. Figure 1 illustrates the basic structure of a batch purifier. The following reference numerals are used in the figure: 1. a storage tank la. engine room 2. process tank 20 3. tank connection 4. inlet 5. transfer pump 6. transfer pump tube 7. control center 25 8. transfer pump level switch 9. air discs c \ j 10. air discs tube δ 11. compressor ^ 12. process sensor o 30 13. chemical pump adjustment 14. chemical pump 15. chemical hose £ 16. drain pump 03 17. outlet o 35 18. slurry pump S 19. slurry pump tube o 20. excess sludge basket 21. engine room bottom 22. flushing tank 40 5

The treatment plant shown in the figure is intended for the treatment of domestic waste water. It comprises two basic parts, namely a storage tank 1, to which the waste water to be purified can be fed through an inlet pipe 4, and a process tank 2, where the actual purification by means of activated sludge takes place. The tanks 1 and 2 are basically separate units 5 connected to each other by a joint 3. The waste water is pumped from the storage tank 1 to the process tank 2 by a transfer pump 5 whose operation is controlled by a level switch 8. The level switch turns on the transfer pump when the surface of the waste water fed to the storage tank exceeds the preset limit, whereby the waste water is pumped through the connection 3 via the transfer tube 6 to the process tank 2.

10 In the present embodiment, a storage room is provided with an engine room having an equipment control center 7 thereon for controlling the operation of the entire unit. Reference numeral 21 refers to the bottom of the engine room which divides the storage tank unit into two parts. By locating the control center 7 with its engine room la within the storage container 1, the control center can be effectively separated and isolated from the environment. Further, a compressor 11 is provided in the engine room 15, which produces compressed air which can be pumped to the process water in the process tank by means of the aerator tube 10 and aerator disks 9 located below this liquid surface. In addition to the above, a chemical pump 14 is provided in the engine room, with control units 13 and chemical hoses 15. The pump 14 supplies the chemical to the process tank 2.

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It is clear that the engine room can be located outside of the storage tank and only one possible application is described above.

In addition to the aeration plates / tube, the process tank of the apparatus has a slurry pump 18 with which

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o 25 the sludge that accumulates in the bottom of the tank can be removed. A storage tank is provided in the storage tank for collecting the slurry cm, i.e. a basket 20, which is connected to the slurry pump co by means of the slurry pipe 19.

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The wastewater pumped into the process tank is aerated by means of air supplied or bubbled through aeration plates, whereby a slurry of microorganisms, i.e. activated sludge, begins to form in the tank. This microorganism / microbial

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under the influence of wastewater, nutrients in the wastewater are degraded to form gas and liquid-soluble degradation products. The latter settle on the sludge to form the activated sludge layer, while the pure water remains on the activated sludge layer. This water 6 is regularly discharged from the tank by means of a pump pump 16. The operation of said pump is controlled by a process sensor 12. The pump is connected to a flushing tank 22 which is connected to a process tank outlet 17.

According to the invention, the pump structure shown in Fig. 1 is implemented as a pump assembly shown in more detail in Figs. 2a and 2b. In Figures 2a and 2b, reference numeral 30 denotes a pump, reference numeral 31 is a flushing tank arranged above the pump, the lower portion 32 being conical and an inlet tube with flanges 33 connected to the outlet pipe 34 of the pump 30. The pump control unit is identified by reference numeral 35 the upper edge of the cylindrical top portion 37 of the container immediately below the end 38 as shown in the figure. The top of the tank has a venting valve 39 for removing air displaced from the tank by the water being pumped into the tank (see arrows). Similarly, a venting valve may be used to introduce replacement air into the container as the container is emptied through its conical lower portion.

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As will be seen from the foregoing, in the preferred embodiment of the invention, the flushing tank 31 is in direct fluid communication with the pump 30 since no valve is fitted between the flush tank inlet 33 and the pump outlet 34. The solution allows the flushing tank to be automatically emptied by gravity when the pump is stopped. The fluid stream 20 exiting the tank then flushes the pump housing.

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Claims (15)

A method for flushing the housing of a drain pump (30) connected to a batch purification process tank, the method comprising passing a liquid through a pump housing to remove the solid therein, characterized in that: used to rinse the drain pump housing 10, wherein the volume of the aqueous suspension pumped into the container is at least equal to the volume of the drain pump housing. Method according to Claim 1, characterized in that the water pump is pumped from the drain pump 15 (30) into a flushing tank (31) located above the pump, from which the aqueous suspension can be returned to the pump housing by gravity. Method according to Claim 1 or 2, characterized in that the flushing tank (31) acts as a buffer to prevent solids from leaving the batch cleaning plant (1). 20 Method according to one of Claims 1 to 3, characterized in that the drainage pump (30) is used to pump the aqueous suspension into the flushing tank (31). A method according to claim 4, characterized in that the duration of the individual o 25 pulses is about 0.1 to 20 seconds, preferably about 0.1 to 5 seconds. cm o i £ 2 A method according to any one of claims 1 to 5, characterized in that the rinsing period g is at least 10 seconds, preferably about 15 seconds to 5 minutes, preferably about 1 minute. CM o 30 to oo Method according to one of the preceding claims, characterized in that, after the CM flushing cycle, the liquid is discharged from the batch purifier via the flushing tank outlet (36). A batch purification drain pump assembly comprising: - a pump (30) having an outlet (34) and an inlet (40) connected to a batch purification process tank, wherein the aqueous suspension from the batch purifier can be discharged from the batch purifier via a pump outlet (34); a flushing tank (31) is provided above the pump having an inlet pipe (33) connected to the pump outlet pipe (34) and an outlet pipe (36) for the batch purification effluent, the tank (31) having a volume at least equal to the pump housing one 10 times. An arrangement according to claim 8, characterized in that the volume of the flushing tank (31) is about 1-10, preferably about 1-5 times the volume of the pump. Arrangement according to Claim 8 or 9, characterized in that the lower part of the flushing tank (31) is shaped like a cone and connected to a pump outlet (34). Arrangement according to one of Claims 8 to 10, characterized in that the flushing container (31) is made of a material which does not substantially adhere to the solid. Arrangement according to Claim 11, characterized in that the flushing tank (31) is made of plastic, in particular of a polyolefin, such as polyethylene or polypropylene, or of a plastic-coated construction material. I 25th Arrangement according to one of Claims 8 to 12, characterized in that a flushing valve (39) is provided in the flushing tank (31). X cc CL Arrangement according to one of Claims 8 to 13, characterized in that the drain tube (3 6) of the flushing tank is arranged at the upper edge of the flushing tank. oo o o c \ j Arrangement according to one of Claims 8 to 14, characterized in that the flushing tank is in direct fluid communication with the pump, whereby the liquid supplied thereto can be automatically emptied by gravity when the pump is stopped.