GB2188656A

GB2188656A - A tank suitable for use in a sewage pumping station

Info

Publication number: GB2188656A
Application number: GB08707922A
Authority: GB
Inventors: Hannu Ilmari Sarvanne; Jari Juhani Narhi; Hans Sixten Jakobsson; Leo Juhani Numminen; Jyrki Juhani Tolvanen; Pekka Reijo Pohjalainen; Lauri Kalevi Peltonen
Original assignee: E Sarlin Oy AB
Current assignee: E Sarlin Oy AB
Priority date: 1986-04-04
Filing date: 1987-04-02
Publication date: 1987-10-07
Also published as: GB2188656B; FI861455A0; FI76166C; GB8707922D0; FI76166B; FI861455A

Abstract

A tank suitable for use in a sewage pumping station comprises a substantially cylindrical main body divided by a partition (4) into two separate spaces, one (2) of which is substantially dry and provided with one or more pumps (5) while the other (3) is for the sewage, said partition being substantially in the form of a circular arc through the whole of its length The curvature of the partition provides for increased strength and ease of manufacture. <IMAGE>

Description

SPECIFICATION Sewage pumping station The present invention concerns a sewage pumping station, which is used for pumping the incoming sewage further e.g. to a sewage purification plant, said pumping station consisting of a container with a substantially cylindrical main body divided by a partition into two separate spaces, one of which is substantially dry and provided with one or more pumps while the other is for the sewage.

There are two basic solutions currently used in sewage pumping stations: those using submersible pumps and those using dry-mounted pumps. When submersible pumps are used, the pumping station consists of a single space and the pumps are immersed in the sewage.

However, since the pumps need servicing from time to time, this solution has certain drawbacks regarding work hygiene (smell, bacteria etc.).

At present there is a trend towards increasing use of dry-mounted pumps in sewage pumping stations. In practice, such stations are provided with a partition dividing the station into two separate spaces, one of which receives the sewage and the other is dry. In the dry space, one or more pumps are installed as required in each case. The pumps communicate with the sewage space via pipes and are started when the sewage level reaches a certain height. The partition between these spaces is usually of a straight design. Two main types are known in this category of pumping station: rectangular stations made of concrete, and cylindrical stations made of reinforced plastic.

The cylindrical reinforced plastic containers are manufactured by a mechanical process of lamination on a rotating drum. The problem with this type of pumping station is the straight partition, which has to be produced by a manual process of lamination. The straight form of the partition involves a disadvantage in respect of strength, which means that the partition requires additional reinforce ment to withstand the hydrostatic pressure of the sewage.

The size requirement of the sewage space depends on the volume flow rate of the incoming sewage. In many cases a fairly small space would be sufficient, so that the partition could be placed close to the cylinder wall.

However, this would make the space inaccessible to the serviceman. Yet the sewage space must be large enough to admit a servi ceman, because the equipment needs cleaning e.g. when the inlet pipe is clogged. Accessi bility is also necessary when major repairs or changes are to be made in the pumping station, to make it possible to block the inlet pipe e.g. by inserting an expanding plug into the pipe orifice. This means that the partition often has to be placed at a greater distance from the cylindrical surface than would be necessary in view of sewage flow requirements, thus involving the drawbacks of a reduced space available for servicing the pumps and increased intervals between pump starting times, which may result in accumulation of sludge on the bottom and other surfaces of the container.Moreover, a sufficient starting frequence of the pumping station is beneficial to the operation of the purification plant because it will ensure a smoother sewage flow.

The object of the present invention is to provide a sewage pumping station which is free of the drawbacks mentioned and can be manufactured at a considerably lower cost than previously known stations. The sewage pumping station of the invention is characterized in that the section of the partition has substantially the form of a circular arc through the whole of its length.

An advantageous embodiment of the invention is characterized in that the centre of curvature of the circular arc is located on the same side of the partition as the sewage space.

Another advantageous embodiment of the invention is characterized in that the centre of curvature of the circular arc is located on the same side of the partition as the pump space.

A further advantageous embodiment of the invention is characterized in that the pump space is substantially cylindrical in form and that the sewage space is located outside it, the partition between these spaces being constituted by that part of the wall of the cylindrical pump space which is shared by the sewage space.

The invention offers many advantages over known types of sewage pumping station. The arc-shaped reinforced plastic partition can eas ily be mechanically produced from a drum-laminated cylinder or a part of such a cylinder.

Moreover, a partition as provided by the invention has an advantage in respect of structural strength, additional reinforcements are unnecessary or they can be incorporated dur ing the lamination process. Further, the parti tion can be placed at a sufficient distance from the cylinder wall to allow for servicing requirements without increasing the sewage space. This means that the pumps will be started at suitable intervals even if the incom ing sewage volume flow is small.

In the following, the invention is described in detail with reference to the drawings attached, wherein: Figure 1 represents a known type of sew age pumping station in sectional view.

Figure 2 represents an embodiment of the invention in perspective.

Figure 3 is a simplified view of the embodi ment in Fig. 2, sectioned along the line Ill-Ill.

Figure 4 shows another embodiment of the invention, sectioned as in Fig. 3.

Figure 5 shows a third embodiment of the invention, sectioned as in Fig. 3.

Figure 6 shows a fourth embodiment of the invention, sectioned as in Fig. 3.

Figure 7 shows a fifth embodiment of the invention, sectioned as in Fig. 3.

Figure 8 shows a sixth embodiment of the invention, sectioned as in Fig. 3.

Figure 9 shows a seventh embodiment of the invention, sectioned as in Fig. 3.

Fig. 1 shows a sectional view of a known type of sewage pumping station having a cylindrical container 1 and a dry pump space 2 separated from the sewage space 3 by a partition 4. The container 1 and the partition are made of reinforced plastic. The pump space 2 houses two dry-mounted pumps 5.

As can be seen from the figure, the partition 4 is of a straight form, involving the drawbacks mentioned before. As regards the technical requirements relating to sewage flow, further advantages could often be gained by placing the partition 4 still closer to the right-hand edge of the section, thus reducing the volume of the sewage space 3, but since this space must be large enough for a serviceman to enter, there is a certain minimum distance X that has to be observed in positioning the partition.

Fig. 2 shows a perspective view of a sewage pumping station as provided by the invention. The difference to the known type of pumping station consists in the curved partition, depicted with broken lines, the various embodiments of which will be explained in connection with the other figures. The pumping station container 1 is provided with an inlet pipe 6 supplying sewage into the the sewage space 3. In this space there is a fluid level sensor (not shown in the figure) which switches the pumps 5 on when the sewage level in the container reaches a certain height.

The sewage is pumped out of the station via the pipe 7 e.g. into a purification plant. The dry pump space 2 and the sewage space 3 are separated by the partition 4, each space having a manhole 8, 9 at the top to provide access for a serviceman. Like known types of sewage pumping station, the pumping station of the invention is made of reinforced plastic.

Pumping stations are generally buried in the ground so that only the manholes remain visible.

The sectional view of the pumping station of Fig. 2, as presented in Fig. 3 unequivocally shows the advantages of an arc-shaped partition. If the largest distance X of the partition 4 from the cylinder wall is the same as in the case of a straight partition, the solution of the invention provides a considerably larger pump space 2. Also, the curved partition is stronger and has greater resistance to the hydrostatic pressure of the sewage. Fig. 3 shows two pumps 5 mounted in the station, but the number of pumps used may vary according to the need. Mounting the pumps in the manner shown in Fig. 3 leaves more space between the pumps for servicing purposes.

Fig. 4 shows an advantageous embodiment of the invention, in which the sewage space 3 is of a cylindrical form and located completely inside the container 1, tangentially touching the latter. The partition 4 between the dry pump space 2 and the sewage space 3 is in this case circular in section.

Fig. 5 shows an advantageous embodiment of the invention, in which the partition 4 is curved in the other direction. This alternative is suitable for stations where the incoming volume flow is larger, in which case the sewage space 3 must be so large that, because of the intervals between pumping cycles, the distance X will be sufficient as a natural consequence.

Fig. 6 shows an embodiment in which the pump space 2 is cylindrical and the sewage space 3 is placed outside it. In this case the partition 4 is constituted by that part of the cylindrical pump compartment wall which is shared by the sewage space 3.

Further possible embodiments of the invention are shown in Figs. 7-9. An advantage will be gained by dimensioning the additional curved wall required by the sewage space 3 in such manner that the length of the arc is equal to the total length of the circumference divided by an integer (=preferably 1-4), so that all parts of the cylinder produced by drum lamination can be utilized to provide components for several pumping stations.

It is obvious to a person skilled in the art that the invention is not restricted to the above examples of its embodiments, but that it may instead be varied in the scope of the following claims.

Claims

1. Sewage pumping, station, which is used to pump the incoming sewage further e.g. to a sewage purification plant, said pumping station consisting of a container (1) with a substantially cylindrical main body divided by a partition (4) into two separate spaces, one (2) of which is substantially dry and provided with one or more pumps (5) while the other (3) is for the sewage, characterized in that the section of the partition has substantially the form of a circular arc through the whole of its length.

2. Sewage pumping station according to claim 1, characterized in that the centre of curvature of the circular arc is located on the same side of the partition (4) as the sewage space (3).

3. Sewage pumping station according to claim 1, characterized in that the centre of curvature of the circular arc is located on the same side of the partition as the pump space (2).

4. Sewage pumping station according to claim 1 or 3, characterized in that the pump space (2) is substantially cylindrical in form and that the sewage space is located outside it, the partition between these spaces being constituted by that part of the wall of the cylindrical pump space (2) which is shared by the sewage space (3).

5. Sewage pumping station according to claim 1 or 2, characterized in that the sewage space (3) is substantially cylindrical in form and located at least partially within the pump space (2), so that the partition (4) between these spaces is constituted by the part of the wall of the cylindrical sewage space (3) which is shared by the pump space (2).

6. Sewage pumping station according to one of the claims 1-5, characterized in that both the pump space (2) and the sewage space (3) are of a substantially cylindrical form and tangentially touch each other.

7. Sewage pumping station according to one of the claims 1-6, characterized in that the additional curved wall required by the sewage space (3) is so dimensioned that the length of the circular arc in the wall section is equal to the total length of the circumference divided by an arbitrary integer, so that all part of the cylinder produced by drum lamination can be utilized to provide components for several pumping stations.

8. A sewage pumping station substantially as herein described with reference to any of Figs. 2 to 9 of the accompanying drawings.