JP2022156777A - Drainage system and method for controlling the same - Google Patents

Abstract

To enable arrangement of a plurality of pumps in a limited space, and to adjust a flow rate in accordance with a flow rate range different for each of pump equipment and a water level difference between a suction water level and a discharge water level.SOLUTION: A drainage system includes a first pump having a rotating shaft connected with an impeller on the suction side, a second pump having a rotating shaft connected with an impeller on the discharge side or the suction side, a connection pipe for connecting a discharge pipe of the first pump and a suction pipe of the second pump, a first discharge valve provided at a position farther from the impeller of the first pump than a connection position with the connection pipe in the discharge pipe of the first pump, a communication valve provided in the connection pipe, and a suction valve provided in the suction pipe of the second pump. When the first pump and the second pump are operated in parallel, the communication valve is closed, and the first discharge valve and the suction valve are opened. When the first pump and the second pump are operated in series, the communication valve is opened, and the first discharge valve and the suction valve are closed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drainage system and its control method.

In recent years, due to climate change, the amount of rainfall has increased compared to before, exceeding the drainage capacity of drainage pumping stations installed for the purpose of draining rainwater, resulting in flooding of rivers and flooding of cities. is increasing.

JP 2015-132173 A

In order to increase the drainage capacity, it is necessary to install a drainage pump facility that is larger than the existing facility. is needed. In addition, when a large pump is installed, the drainage capacity drops significantly when the pump equipment is maintained or breaks down, so there is also a problem from the viewpoint of risk dispersion. In order to solve this problem, it is conceivable to use small pump equipment that can be designed and manufactured in a standard manner from the existing pump equipment, increase the number of pump equipment, increase the drainage capacity, and disperse the danger. However, when arranging a lot of drainage pump equipment in the installation space of the existing drainage pump station, there is a problem of the arrangement method in the limited space.

In the background described above, it is conceivable to use small pumps with standardized performance in the existing pump equipment. In order to enhance the drainage function of existing pump equipment, it is possible to operate small pumps in parallel. It may not be possible to discharge the required flow rate. When installing standardized small pumps in existing pump equipment, it is necessary to configure the equipment to widely handle the different flow ranges and water level differences between the suction water level and the discharge water level for each pump equipment.

The present invention has been made in view of the above problems, and when a plurality of pumps are installed, it is possible to arrange them in a limited space, and at the same time, the flow rate range and the water level difference between the suction water level and the discharge water level differ for each pump equipment. It is an object of the present invention to provide a drainage system and its control method that can adjust the flow rate accordingly.

A drainage system according to a first aspect of the present invention includes a first pump, a second pump, a connection pipe connecting a discharge pipe of the first pump and a suction part or a pump casing of the second pump, a first discharge valve provided in a discharge pipe of one pump at a position farther from the impeller of the first pump than a connection position with the connection pipe; a communication valve provided in the connection pipe; a suction valve provided in a suction pipe of the second pump, wherein when the first pump and the second pump are operated in parallel, the communication valve is closed and the first discharge valve is closed. and the suction valve are open, and when the first pump and the second pump operate in series, the communication valve is opened and the first discharge valve and the suction valve are closed.

According to this configuration, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, since the arrangement of the first pump and the second pump can be made variable, they can be arranged in a limited space.

A drainage system according to a second aspect of the present invention is the drainage system according to the first aspect, comprising a second discharge valve provided in a discharge pipe of the second pump, and the second pump operate in series or in parallel, the second discharge valve is open.

A drainage system according to a third aspect of the present invention is the drainage system according to the first or second aspect, wherein the suction pipe of the first pump and the suction pipe of the second pump are connected to a suction collecting pipe. It is

A control method according to a fourth aspect of the present invention is a control method for shifting the drainage system according to any one of the first to third aspects from parallel operation to series operation, wherein the first discharge valve and It has a procedure of closing the second discharge valve, a procedure of fully closing the communication valve, a procedure of fully closing the suction valve, and a procedure of fully opening the second discharge valve.

According to this configuration, parallel operation can be changed to series operation.

According to one aspect of the present invention, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, since the arrangement of the first pump and the second pump can be made variable, they can be arranged in a limited space.

1 is a plan view of a drainage system according to a first embodiment; FIG. It is a system diagram at the time of parallel operation in each embodiment. It is a system diagram at the time of series operation in each embodiment. It is an example of the graph which shows the relationship between the head and flow rate at the time of parallel operation. It is an example of the graph which shows the relationship between the head and flow rate at the time of series operation. It is a top view of the drainage system concerning the 1st modification of 1st Embodiment. It is a top view of the drainage system concerning the 2nd modification of 1st Embodiment. FIG. 11 is a plan view of a drainage system according to a third modified example of the first embodiment; It is a top view of the drainage system which concerns on 2nd Embodiment. FIG. 9B is a cross-sectional view taken along the line AA of FIG. 9A; It is the figure which looked at the suction collection pipe from the side at the time of utilization of the existing suction water tank. It is the figure which looked at the suction collection pipe from the side at the time of utilization of the existing suction inflow part. 4 is a flowchart showing an example of the flow of processing for changing from parallel operation to series operation in each embodiment.

Hereinafter, each embodiment will be described with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art.

1 is a plan view of a drainage system according to a first embodiment; FIG. As shown in FIG. 1, a drainage system 101 according to the first embodiment includes a first pump 1 and a second pump 2. As shown in FIG. Here, as an example, the first pump 1 is a horizontal shaft pump in which the rotating shaft connected to the impeller is on the suction side (that is, the shaft-penetrating portion of the suction pipe is on the suction side). The second pump 2 is, for example, a horizontal shaft pump in which the rotary shaft connected to the impeller is on the suction side (that is, the shaft-penetrating portion of the suction pipe is on the suction side).

The first pump 1 has a rotary shaft 14 connected to a drive shaft 16 of a first prime mover 15 via a first speed reducer 17 . The first prime mover 15 is, for example, an electric motor, a diesel engine, or a gas turbine. The first speed reducer 17 is, for example, a parallel shaft gear speed reducer, and has, for example, a driving gear 171 and a driven gear 172 , and the driving gear 171 meshes with the driven gear 172 .

A drive shaft 16 of the first prime mover 15 is connected to a drive gear 171 of the first speed reducer 17 and a driven gear 172 is connected to the rotary shaft 14 . With such a configuration, the power from the first prime mover 15 is transmitted to the rotary shaft 14 at a predetermined reduction ratio, and the rotary shaft 14 can be rotated at a desired rotational speed.

The first pump 1 has an impeller 11 which is fixed to a horizontally extending rotating shaft 14 and rotates as the rotating shaft 14 rotates.
The first pump 1 has a pump casing 12 housing the impeller 11 and a suction casing 131 connected to one end of the pump casing 12 . One end of the suction casing 131 is connected to the pump casing 12, one end of the curved suction pipe 132 is connected to the other end of the suction casing 131, and the other end is submerged in liquid in a suction water tank (not shown). . In addition, the suction casing 131 and the curved suction pipe 132 form the suction section 13, and the suction section 13 is configured to be curved.
The first pump 1 further includes a discharge pipe 18, one end of which is connected to the other end of the pump casing 12, and the other end of which is provided in a discharge water tank (not shown).

Similarly, the second pump 2 has a rotary shaft 24 connected to a drive shaft 26 of a second prime mover 25 via a second reducer 27 . The second prime mover 25 is, for example, an electric motor, a diesel engine, or a gas turbine. The second speed reducer 27 is, for example, a parallel shaft gear speed reducer, and has, for example, a drive gear 271 and a driven gear 272 , and the drive gear 271 meshes with the driven gear 272 .

The drive shaft 26 of the second prime mover 25 is connected to the drive gear 271 of the second speed reducer 27 and the driven gear 272 is connected to the rotary shaft 24 . With such a configuration, the power from the second prime mover 25 is transmitted to the rotating shaft 24 at a predetermined speed reduction ratio, so that the rotating shaft 24 can be rotated at a desired rotational speed.

The second pump 2 has an impeller 21 which is fixed to a horizontally extending rotating shaft 24 and rotates as the rotating shaft 24 rotates. The second pump 2 has a pump casing 22 housing the impeller 21 and a suction casing 231 connected to one end of the pump casing 22 .

One end of the suction casing 231 is connected to the pump casing 22 , one end of the curved suction pipe 232 is connected to the other end of the suction casing 231 , and the other end is connected to one end of the suction pipe 29 . The other end of this suction pipe 29 is provided in a suction water tank (not shown). In addition, the suction portion 23 is formed by the suction casing 231 and the curved suction pipe 232, and the suction portion 23 is configured to be curved.
The drainage system 101 comprises a suction valve V21 provided on the suction pipe 29 of the second pump 2 . Further, the second pump 2 has a discharge pipe 28 connected to the other end of the pump casing 22, and this discharge pipe 28 is provided with a second discharge valve V22.

The drainage system 101 includes an evacuation pipe 33 communicating with the pump casing 12 of the first pump, and an intake valve 31 provided in the evacuation pipe 33 . The drainage system 101 may be provided with not only the intake valve 31 but also a full-water detector and a vacuum breaking valve in the evacuation pipe 33 .

The drainage system 101 also includes an evacuation pipe 34 communicating with the pump casing 22 of the second pump, and an intake valve 32 provided in the evacuation pipe 34 . The drainage system 101 may be provided with not only the intake valve 32 but also a full-water detector and a vacuum breaking valve in the evacuation pipe 33 .
The drainage system 101 also includes a vacuum pipe 35 with one end communicating between the vacuum pipes 33 and 34 , and a vacuum pump 36 communicating with the other end of the vacuum pipe 35 .

The drainage system 101 further comprises a connecting pipe 30 connecting the discharge pipe 18 and the suction part 23 of the second pump. Further, the drainage system 101 includes a communication valve V1 provided on the connecting pipe 30. As shown in FIG. Further, the drainage system 101 includes a first discharge valve V12 provided in the discharge pipe 18 of the first pump at a position farther from the impeller 11 of the first pump 1 than the connection position with the connection pipe 30 .

<Drainage system diagram>
Next, a system diagram of a drainage system according to each embodiment will be described with reference to FIGS. 2A and 2B. FIG. 2A is a system diagram during parallel operation in each embodiment. FIG. 2B is a system diagram during series operation in each embodiment.

As shown in FIG. 2A, when the first pump 1 and the second pump 2 operate in parallel, the communication valve V1 is closed and the first discharge valve V12 and the suction valve V21 are opened. As a result, the liquid is sucked from the suction water tank by the first pump 1 and discharged to the discharge water tank, and in parallel with this, the liquid is sucked from the suction water tank by the second pump 2 and discharged to the discharge water tank. This allows the first pump 1 and the second pump 2 to operate in parallel.

On the other hand, as shown in FIG. 2B, when the first pump 1 and the second pump 2 operate in series, the communication valve V1 is opened and the first discharge valve V12 and the suction valve V21 are closed. As a result, the liquid sucked from the suction water tank and discharged by the first pump flows into the suction side of the second pump and is discharged from the second pump to the discharge water tank. The second discharge valve V22 is open both during parallel operation and during series operation.

FIG. 3 is an example of a graph showing the relationship between head and flow during parallel operation. FIG. 3 shows a pipe loss curve W1, an existing pump performance curve W2, a single small pump performance curve W3, and a small pump parallel operation performance curve W4. Here, it is assumed that the difference between the discharge water level and the suction water level in the existing pump equipment is Ha in FIG.

Here, since the existing pump equipment operates with the intersection point P1 between the pipe loss curve W1 and the existing pump performance curve W2 as the operating point, the discharge flow rate is Q1 as shown in FIG. For example, in existing pump equipment, if the discharge flow rate Q (≤Q1) required for actual operation is larger than the maximum flow rate of one small pump, the pumps are operated in parallel. In that case, since the operation is performed with the pipe loss curve W1 and the small pump parallel operation performance curve W4 intersecting point P2 as the operating point, the discharge flow rate is Q2 (>Q1) in FIG. 3, and the discharge flow rate required for actual operation can be satisfied. can. Furthermore, the discharge flow rate Q2 can be increased from the discharge flow rate Q1 of the existing pump equipment. Further, the lift at that time can be made higher than the difference Ha between the discharge water level and the suction water level.

FIG. 4 is an example of a graph showing the relationship between head and flow during series operation. FIG. 4 shows a pipe loss curve W11, an existing pump performance curve W12, a single small pump performance curve W13, and a small pump serial operation performance curve W14. Here, it is assumed that the difference between the discharge water level and the suction water level in the existing pump equipment is Ha in FIG.

Since the existing pump facility operates with the intersection point P3 between the pipe loss curve W11 and the existing pump performance curve W12 as the operating point, the head is H3 as shown in FIG. For example, in existing pump equipment, if the difference Ha between the discharge water level and the suction water level in this existing pump equipment is higher than the maximum head of one small pump, the pumps are operated in series. In this case, since the operation is performed with the pipe loss curve W11 and the small pump series operation performance curve W14 intersecting point P4 as the operating point, the head H4 can be made higher than the difference Ha between the discharge water level and the suction water level, and water is supplied to the discharge water tank. can be pumped up. Furthermore, the lift H4 at this time can be made higher than the lift H3 in the existing pump equipment. Further, the discharged water quantity Q4 at that time can be made larger than the discharged water quantity Q3 of the existing pump equipment.

The drainage system according to the first embodiment includes a first pump whose rotating shaft connected to the impeller is on the suction side, a second pump whose rotating shaft is connected to the impeller on the suction side, and a second pump. A connection pipe connecting a discharge pipe of one pump and a suction pipe of a second pump, and a position farther from the impeller of the first pump than a connection position of the connection pipe in the discharge pipe of the first pump a first discharge valve provided in the first pump, a communication valve provided in the connection pipe, and a suction valve provided in the suction pipe of the second pump; When the pumps operate in parallel, the communication valve is closed, the first discharge valve and the suction valve are open, and the first pump and the second pump operate in series, The communication valve is opened and the first discharge valve and the suction valve are closed.

According to this configuration, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, by arranging a combination of pumps with a rotation shaft penetrating position on the suction side and pumps with a position on the suction side, they can be arranged in a limited space.

<First Modification of First Embodiment>
5 is a plan view of a drainage system according to a first modification of the first embodiment; FIG. A drainage system 102 according to a first modification of the first embodiment in FIG. 5 differs from that in FIG. 13 is changed from the left side to the right side. Further, the configuration of the second pump 2 is changed to a second pump 2b. In this second pump 2b, the pump casing 22 is changed to the suction side and connected to the suction pipe 29b, and the suction portion 23 discharges. It is different in that it is provided on the side and changed to a discharge portion 23b, and functions as a discharge pipe instead of a suction pipe and is connected to a discharge pipe 28. That is, the rotary shaft 24 connected to the impeller 21 is changed to be positioned on the discharge side. Accordingly, the suction casing 231 is changed to a discharge casing 232b, and the curved suction pipe 232 is changed to a curved discharge pipe 232b.

Also in this configuration, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, by arranging a combination of a pump having a rotary shaft penetrating position on the suction side and a pump having a rotary shaft penetrating position on the discharge side, they can be arranged in a limited space.

<Second Modification of First Embodiment>
FIG. 6 is a plan view of a drainage system according to a second modification of the first embodiment; A drainage system 103 according to a second modification of the first embodiment shown in FIG. The difference is the placement.

Also in this configuration, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, by arranging a combination of pumps with a rotation shaft penetrating position on the suction side and pumps with a position on the suction side, they can be arranged in a limited space.

<Third Modification of First Embodiment>
7 is a plan view of a drainage system according to a third modification of the first embodiment; FIG. In a drainage system 104 according to a third modification of the first embodiment in FIG. 7, the first pump 1 is arranged above the page and the second pump is below the page compared to FIG. The difference is the placement. Furthermore, in the drainage system 104 according to the third modification of the first embodiment shown in FIG. changed from left to right. Furthermore, the configuration of the second pump 2 is changed to a second pump 2c, in which the suction pipe 29 is horizontally extended, and the connection pipe 30 is connected to the suction pipe 29 instead of the suction portion 23. The difference is that it is connected to Thereby, the second prime mover 25 and the second speed reducer 27 can be arranged in a position surrounded by the discharge pipe 19 , the connection pipe 30 , the suction pipe 29 and the suction portion 23 .

Also in this configuration, by switching between series operation and parallel operation, a standardized small pump can be used to handle a wide flow rate range and a water level difference between the suction water level and the discharge water level. Furthermore, since the arrangement of the first pump and the second pump can be made variable, they can be arranged in a limited space.

<Second embodiment>
Next, a second embodiment will be described. 8A is a plan view of a drainage system according to a second embodiment; FIG. FIG. 8B is a cross-sectional view taken along line AA of FIG. 8A. As shown in FIG. 8A, the drainage system 105 according to the second embodiment has a suction collecting pipe 41, one end of which is immersed in the water of the suction water tank, compared to the drainage system 101 according to the second embodiment of FIG. The difference is that a suction collecting pipe 42 connected to this suction collecting pipe 41 is further provided. Furthermore, one end of the suction pipe 19 is connected to this suction collecting pipe 42 , and one end of the suction pipe 29 is connected to this suction collecting pipe 42 . 8A, the connection pipe 30 of FIG. 1 is changed to a connection pipe 30b having a different shape. A drainage system 105 is provided on the foundation 51, as shown in FIG. 8B.

FIG. 9A is a side view of the suction collecting pipe when using the existing suction water tank. As shown in FIG. 9A, one end of the suction collecting pipe 41 is submerged below the water surface of the suction water tank. FIG. 9B is a side view of the suction collecting pipe when using the existing suction inlet. As shown in FIG. 9B, one end of the suction collecting pipe 41 is submerged below the water surface of the suction water tank. In FIG. 9B, an existing suction water tank 52 is provided under a foundation 51 . Note that the existing suction water tank 52 may be the ground instead of the water tank.

As described above, according to the second embodiment, it is possible to reduce the number of suction pipes for each pump even by combining the proposed layout suction collecting pipe and the above-described pump arrangement, and further space saving is possible.

<Flow of processing for changing from parallel operation to series operation>
Next, an example of the flow of processing for changing from parallel operation to series operation in each embodiment will be described with reference to FIG. 10 . FIG. 10 is a flowchart showing an example of the flow of processing for changing from parallel operation to series operation in each embodiment. This process of changing from parallel operation to series operation may be performed, for example, when the required head becomes higher than a threshold value (for example, a desired set value that is equal to or less than the head of one pump) due to water level fluctuations. good. In the following explanation, the control described in the passive state without specifying the main body of control may be performed by a control device (not shown) provided in the drainage system, or may be performed manually by the operator. .

(Step S10) First, as an initial condition, the first pump 1 and the second pump 2 are operated in parallel. In this parallel operation state, the suction valve V21 of the second pump 2 is "fully open", the communication valve V1 is "fully closed", the first discharge valve V12 of the first pump is "fully open", and the second pump 2 , the second discharge valve V22 is "fully open".

(Step S20) Next, the first discharge valve V12 of the first pump 1 and the second discharge valve V22 of the second pump 2 are closed. In this way, the pump shut-off operation is continued.

(Step S30) Next, the communication valve V1 is fully opened.

(Step S40) Next, the suction valve V21 of the second pump is fully closed.

(Step S50) Next, the second discharge valve V22 of the second pump is fully opened.
This completes the transition to the series operation drain state. In this series operation, the suction valve V21 of the second pump is "fully closed", the communication valve V1 is "fully open", the first discharge valve V12 of the first pump is "fully closed", and the second pump 2 discharge valve V22 is "full open".

Instead of switching from parallel operation to series operation as described above, parallel operation may be performed, and series operation may be performed in series. If parallel to series or series to parallel is to be changed, the pump may be stopped and restarted.

As described above, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the present invention at the implementation stage. Further, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components across different embodiments may be combined as appropriate.

1 First Pumps 101, 102, 103, 104, 105 Drainage System 11 Impeller 12 Pump Casing 13 Suction Portion 131 Suction Casing 132 Bent Suction Pipe 14 Rotary Shaft 15 First Motor 16 Drive Shaft 17 First Reducer 171 Drive gear 172 Driven gear 18 Discharge pipe 19 Suction pipes 2, 2b, 2c Second pump 21 Impeller 22 Pump casing 23 Suction part 23b Discharge part 231 Suction casing 231b Discharge casing 232 Suction curved pipe 232b Discharge curved pipe 24 Rotating shaft 25 Second motor 26 Drive shaft 27 Second reducer 271 Drive gear 272 Driven gear 28 Discharge pipe 29 Suction pipe 29b Suction pipes 30, 30b Connection pipe 31 Intake valve 32 Intake valve 33 Evacuation pipe 34 Evacuation pipe 35 Evacuation piping 36 Vacuum pumps 41, 42 Suction collecting pipe 51 Foundation 52 Existing suction water tank V12 First discharge valve V21 Suction valve V22 Second discharge valve

Claims (4)

a first pump;
a second pump;
a connection pipe that connects the discharge pipe of the first pump and the suction part or pump casing of the second pump;
a first discharge valve provided in the discharge pipe of the first pump at a position farther from the impeller of the first pump than the connection position with the connection pipe;
a communication valve provided in the connection pipe;
a suction valve provided in the suction pipe of the second pump;
with
when the first pump and the second pump are operated in parallel, the communication valve is closed and the first discharge valve and the suction valve are opened;
When the first pump and the second pump operate in series, the communication valve is opened and the first discharge valve and the suction valve are closed. Drainage system. A second discharge valve provided in the discharge pipe of the second pump,
The second discharge valve is open when the first pump and the second pump operate in series or in parallel.
The drainage system according to claim 1. The drainage system according to claim 1 or 2, wherein the suction pipe of the first pump and the suction pipe of the second pump are connected to a suction collecting pipe. A control method for transferring the drainage system according to any one of claims 1 to 3 from parallel operation to series operation,
closing the first discharge valve and the second discharge valve;
a procedure of fully closing the communication valve;
a procedure for fully closing the suction valve;
a procedure of fully opening the second discharge valve;
A control method with

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