JP7607495B2 - Drainage system and method for controlling same - Google Patents

Description

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

In recent years, climate change has caused increased rainfall compared to the past, exceeding the drainage capacity of pumping stations installed for the purpose of draining rainwater, and the inability to drain all the rainwater has led to increased river flooding and flooding in cities.

JP 2015-132173 A

In order to increase drainage capacity, it is necessary to install drainage pump equipment larger than the existing equipment, but this requires designing and manufacturing drainage pump equipment in accordance with the conditions of use and local restrictions, which requires a huge amount of money and time. Furthermore, when large pumps are installed, drainage capacity drops significantly during maintenance or when the pump equipment breaks down, which poses issues in terms of risk dispersion. To address this issue, one possible method is to use smaller pump equipment, which can be designed and manufactured in a standard manner compared to existing pump equipment, and to increase the number of units, thereby increasing drainage capacity and dispersing risk. However, when installing a large number of drainage pump equipment in the installation space of an existing drainage pumping station, issues arise as to how to arrange them in the limited space.

In the context of the above, it is possible to consider using small pumps with standardized performance in existing pump equipment. When increasing the drainage function of existing pump equipment, this can be done by operating small pumps in parallel; however, in existing pump equipment in an environment where there is a large difference in water level between the suction water level and the discharge water level, small pumps may not have enough head to discharge the required flow rate. When installing standardized small pumps in existing pump equipment, the equipment configuration is required to be able to widely accommodate the different flow rate ranges and water level differences between the suction water level and the discharge water level for each pump equipment.

The present invention was made in consideration of the above problems, and aims to provide a drainage system and a control method thereof that allows multiple pumps to be installed in a limited space and allows the flow rate to be adjusted according to the flow rate range that differs for each pump facility and the water level difference between the suction water level and the discharge water level.

The drainage system according to the first aspect of the present invention comprises a first pump, a second pump, a connecting pipe connecting the discharge pipe of the first pump to the suction section 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 connecting pipe, a communication valve provided in the connecting 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 open, and 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.

With this configuration, by switching between series and parallel operation, a standardized small pump can be used to accommodate a wide range of flow rates and the difference in water level between the suction and discharge water levels. Furthermore, the placement of the first and second pumps can be changed, allowing them to be placed in a limited space.

The drainage system according to the second aspect of the present invention is the drainage system according to the first aspect, further comprising a second discharge valve provided in the discharge pipe of the second pump, and when the first pump and the second pump are operated in series or in parallel, the second discharge valve is open.

The drainage system according to the third aspect of the present invention is the drainage system according to the first or second aspect, in which the suction pipe of the first pump and the suction pipe of the second pump are connected to a suction manifold.

The control method according to the fourth aspect of the present invention is a control method for transitioning the drainage system according to any one of the first to third aspects from parallel operation to series operation, and includes the steps of closing the first discharge valve and the second discharge valve, fully closing the communication valve, fully closing the suction valve, and fully opening the second discharge valve.

This configuration allows you to change from parallel operation to series operation.

According to one aspect of the present invention, by switching between series and parallel operation, a standardized small pump can be used to accommodate a wide range of flow rates and the difference in water level between the suction water level and the discharge water level. Furthermore, the arrangement of the first and second pumps can be changed, allowing them to be placed in a limited space.

FIG. 1 is a plan view of a drainage system according to a first embodiment. FIG. 4 is a system diagram during parallel operation in each embodiment. FIG. 4 is a system diagram during series operation in each embodiment. 1 is an example of a graph showing a relationship between head and flow rate during parallel operation. 1 is an example of a graph showing the relationship between head and flow rate during series operation. FIG. 2 is a plan view of a drainage system according to a first modified example of the first embodiment. FIG. 11 is a plan view of a drainage system according to a second modified example of the first embodiment. FIG. 11 is a plan view of a drainage system according to a third modified example of the first embodiment. FIG. 11 is a plan view of a drainage system according to a second embodiment. This is a cross-sectional view of AA in Figure 9A. This is a side view of the suction manifold when using the existing suction tank. This is a side view of the suction manifold when using the existing suction inlet section. 5 is a flowchart showing an example of a process flow for changing from parallel operation to series operation in each embodiment.

Each embodiment will be described below with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to make it easier for those skilled in the art to understand.

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

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

The drive shaft 16 of the first prime mover 15 is connected to the drive gear 171 of the first reducer 17, and the driven gear 172 is connected to the rotating shaft 14. With this configuration, the power from the first prime mover 15 is transmitted to the rotating shaft 14 at a predetermined reduction ratio, allowing the rotating shaft 14 to rotate at a desired rotational speed.

The first pump 1 has an impeller 11 which is fixed to a rotating shaft 14 extending horizontally, and the impeller 11 rotates as the rotating shaft 14 rotates.
The first pump 1 has a pump casing 12 that houses 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, and one end of a suction bend 132 is connected to the other end of the suction casing 131, and the other end is submerged in the liquid in a suction water tank (not shown). The suction casing 131 and the suction bend 132 form a suction section 13, which 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 rotating shaft 24 connected to the drive shaft 26 of the 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 reducer 27 is, for example, a parallel shaft gear 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 reducer 27, and the driven gear 272 is connected to the rotating shaft 24. With this configuration, the power from the second prime mover 25 is transmitted to the rotating shaft 24 at a predetermined reduction ratio, and 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 rotating shaft 24 extending horizontally, and the impeller 21 rotates with the rotation of the rotating shaft 24. The second pump 2 has a pump casing 22 in which the impeller 21 is housed, 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, and one end of the suction bend 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 the suction pipe 29 is provided in a suction water tank (not shown). The suction casing 231 and the suction bend 232 form the suction section 23, which is configured to be curved.
The drainage system 101 includes a suction valve V21 provided in a suction pipe 29 of the second pump 2. The second pump 2 further includes a discharge pipe 28 connected to the other end of the pump casing 22, and a second discharge valve V22 is provided in the discharge pipe 28.

The drainage system 101 includes a vacuum piping 33 that communicates with the pump casing 12 of the first pump, and an intake valve 31 provided in the vacuum piping 33. In addition to the intake valve 31, the drainage system 101 may also include a full water detector and a vacuum breaker valve provided in the vacuum piping 33.

The drainage system 101 also includes a vacuum piping 34 that communicates with the pump casing 22 of the second pump, and an intake valve 32 provided in the vacuum piping 34. In the drainage system 101, in addition to the intake valve 32, a full water detector and a vacuum breaker valve may be provided in the vacuum piping 33.
The drainage system 101 also includes a vacuum pipe 35 whose one end communicates with the vacuum pipes 33 and 34 , and a vacuum pump 36 whose other end communicates with the vacuum pipe 35 .

The drainage system 101 further includes a connecting pipe 30 that connects the discharge pipe 18 and the suction section 23 of the second pump. The drainage system 101 further includes a communication valve V1 provided on the connecting pipe 30. The drainage system 101 further includes a first discharge valve V12 provided on 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 connecting pipe 30.

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

As shown in FIG. 2A, when the first pump 1 and the second pump 2 are operated in parallel, the communication valve V1 is closed, and the first discharge valve V12 and the suction valve V21 are open. This causes the first pump 1 to suck liquid from the suction tank and discharge it into the discharge tank, while in parallel the second pump 2 sucks liquid from the suction tank and discharges it into the discharge 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 are operated 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 in from the suction 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 tank. The second discharge valve V22 is open both during parallel operation and during series operation.

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

The existing pump equipment is operated with the intersection P1 between the piping loss curve W1 and the existing pump performance curve W2 as the operating point, resulting in a discharge flow rate Q1 as shown in Figure 3. For example, with an existing pump equipment, if the discharge flow rate Q (≦Q1) required for actual operation is greater than the maximum flow rate of a single small pump, the pumps are operated in parallel. In that case, the pumps are operated with the intersection P2 between the piping loss curve W1 and the small pump parallel operation performance curve W4 as the operating point, resulting in the discharge flow rate Q2 (>Q1) in Figure 3, which satisfies the discharge flow rate required for actual operation. Furthermore, the discharge flow rate Q2 can be increased above the discharge flow rate Q1 of the existing pump equipment. Also, the head at that time can be made higher than the difference Ha between the discharge water level and the suction water level.

Figure 4 is an example of a graph showing the relationship between head and flow rate during series operation. Figure 4 shows a piping loss curve W11, an existing pump performance curve W12, a single small pump performance curve W13, and a series operation performance curve W14 of small pumps. Here, the difference between the discharge water level and the suction water level in the existing pump equipment is assumed to be Ha in Figure 4.

In the existing pump equipment, the operation point is the intersection P3 between the piping loss curve W11 and the existing pump performance curve W12, resulting in a head H3 as shown in Figure 4. For example, in the case of an 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 a single small pump, the pumps are operated in series. In this case, the operation point is the intersection P4 between the piping loss curve W11 and the small pump series operation performance curve W14, so the head H4 can be made higher than the difference Ha between the discharge water level and the suction water level, and water can be pumped up to the discharge water tank. Furthermore, the head H4 at this time can be made higher than the head H3 in the existing pump equipment. Also, the discharge water volume Q4 at this time can be made higher than the discharge water volume Q3 of the existing pump equipment.

The drainage system according to the first embodiment includes a first pump having a rotating shaft connected to an impeller on the suction side, a second pump having a rotating shaft connected to an impeller on the suction side, a connecting pipe connecting the discharge pipe of the first pump and the suction pipe 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 connecting pipe, a communication valve provided in the connecting 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 open, and 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.

With this configuration, by switching between series and parallel operation, a wide range of flow rates and the difference in water level between the suction and discharge water levels can be handled using standardized small pumps. Furthermore, by combining and arranging pumps with the rotating shaft penetrating position on the suction side and pumps with the rotating shaft penetrating 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. The drainage system 102 according to the first modification of the first embodiment in FIG. 5 is different from FIG. 1 in the arrangement of the suction section 13 of the first pump 1, and the arrangement of the suction bend 132 when the shaft penetration part of the suction section 13 is seen from the impeller 11 is changed from the left side to the right side. Furthermore, the configuration is changed from the second pump 2 to the second pump 2b, and in this second pump 2b, the pump casing 22 is changed to the suction side and connected to the suction piping 29b, the suction section 23 is provided on the discharge side and changed to the discharge section 23b, and functions as a discharge pipe instead of a suction pipe and is connected to the discharge pipe 28. That is, the rotating shaft 24 connected to the impeller 21 is changed to be located on the discharge side. Accordingly, the suction casing 231 is changed to the discharge casing 232b, and the suction bend 232 is changed to the discharge bend 232b.

Similarly, with this configuration, by switching between series and parallel operation, a wide range of flow rates and the difference in water level between the suction and discharge water levels can be handled using standardized small pumps. Furthermore, by combining and arranging pumps with the rotating shaft penetrating the suction side and pumps with the rotating shaft penetrating the discharge side, they can be arranged in a limited space.

<Second Modification of the First Embodiment>
Fig. 6 is a plan view of a drainage system according to a second modified example of the first embodiment. The drainage system 103 according to the second modified example of the first embodiment in Fig. 6 is different from Fig. 1 in that the first pump 1 is disposed on the upper side of the paper and the second pump is disposed on the lower side of the paper.

Similarly, with this configuration, by switching between series and parallel operation, a wide range of flow rates and the difference in water level between the suction and discharge water levels can be handled using standardized small pumps. Furthermore, by combining and arranging pumps with the rotating shaft penetrating position on the suction side and pumps on the suction side, they can be arranged in a limited space.

<Third Modification of the First Embodiment>
7 is a plan view of a drainage system according to a third modified example of the first embodiment. The drainage system 104 according to the third modified example of the first embodiment in FIG. 7 is different from FIG. 1 in that the first pump 1 is arranged on the upper side of the paper and the second pump is arranged on the lower side of the paper. Furthermore, the drainage system 104 according to the third modified example of the first embodiment in FIG. 7 is different from FIG. 1 in that the arrangement of the suction part 13 is changed from the left side to the right side when the shaft penetration part of the suction part 13 is seen from the impeller 11. Furthermore, the configuration is changed from the second pump 2 to the second pump 2c, and in this second pump 2c, the suction pipe 29 is extended in the horizontal direction, and the connecting pipe 30 is connected to the suction pipe 29 instead of the suction part 23. This allows the second prime mover 25 and the second reducer 27 to be arranged in a position surrounded by the discharge pipe 19, the connecting pipe 30, the suction pipe 29, and the suction part 23.

Similarly, with this configuration, by switching between series and parallel operation, a standardized small pump can be used to accommodate a wide range of flow rates and the difference in water level between the suction and discharge water levels. Furthermore, the placement of the first and second pumps can be changed, allowing them to be placed in a limited space.

Second Embodiment
Next, the second embodiment will be described. FIG. 8A is a plan view of the drainage system according to the second embodiment. FIG. 8B is a cross-sectional view taken along the line A-A of FIG. 8A. As shown in FIG. 8A, the drainage system 105 according to the second embodiment is different from the drainage system 101 according to the second embodiment of FIG. 1 in that it further includes a suction collector pipe 41, one end of which is immersed in the water of the suction water tank, and a suction collector pipe 42 connected to the suction collector pipe 41. Furthermore, one end of the suction pipe 19 is connected to the suction collector pipe 42, and one end of the suction pipe 29 is connected to the suction collector pipe 42. Also, in FIG. 8A, the connecting pipe 30 in FIG. 1 is changed to a connecting pipe 30b having a different shape. As shown in FIG. 8B, the drainage system 105 is provided on a foundation 51.

Figure 9A is a side view of the suction manifold when the existing suction tank is in use. As shown in Figure 9A, one end of the suction manifold 41 is immersed below the water level of the suction tank. Figure 9B is a side view of the suction manifold when the existing suction inlet is in use. As shown in Figure 9B, one end of the suction manifold 41 is immersed below the water level of the suction tank. In Figure 9B, an existing suction tank 52 is provided below a foundation 51. Note that the existing suction tank 52 may be the ground rather than a tank.

As described above, according to the second embodiment, the number of suction pipes for each pump can be reduced by combining the proposed layout suction manifold with the pump arrangement described above, enabling further space savings.

<Process flow for changing from parallel operation to series operation>
Next, an example of the process flow 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 process flow for changing from parallel operation to series operation in each embodiment. This process for 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 lower than the head of one pump) due to a water level fluctuation. In the following description, control described in the passive voice without specifying the control entity may be performed by a control device (not shown) provided in the drainage system or may be performed manually by an 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 discharge valve V22 of the second pump 2 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 continues.

(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.
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 discharge valve V22 of the second pump is fully open.

In addition, instead of switching from parallel to series operation as described above, you can operate the pumps in parallel or in series. If you are switching from parallel to series or from series to parallel, you can stop the pump once and restart it.

As mentioned above, the present invention is not limited to the above-mentioned embodiment as it is, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above-mentioned embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined.

1 First pump 101, 102, 103, 104, 105 Drainage system 11 Impeller 12 Pump casing 13 Suction section 131 Suction casing 132 Suction elbow 14 Rotating shaft 15 First prime mover 16 Drive shaft 17 First reducer 171 Drive gear 172 Driven gear 18 Discharge pipe 19 Suction pipe 2, 2b, 2c Second pump 21 Impeller 22 Pump casing 23 Suction section 23b Discharge section 231 Suction casing 231b Discharge casing 232 Suction elbow 232b Discharge elbow 24 Rotating shaft 25 Second prime mover 26 Drive shaft 27 Second reducer 271 Drive gear 272 Driven gear 28 Discharge pipe 29 Suction pipe 29b Suction piping 30, 30b Connecting pipe 31 Intake valve 32 Intake valve 33 Vacuum suction pipe 34 Vacuum suction pipe 35 Vacuum suction pipe 36 Vacuum pump 41, 42 Suction manifold pipe 51 Foundation 52 Existing suction water tank V12 First discharge valve V21 Suction valve V22 Second discharge valve

Claims (3)

A first pump;
A second pump; and
a connecting pipe connecting a discharge pipe of the first pump and a suction portion or a pump casing of the second pump;
a first discharge valve provided in a discharge pipe of a first pump at a position farther from an impeller of the first pump than a connection position between the discharge pipe and the connecting pipe;
A communication valve provided in the connecting pipe;
a suction valve provided in a suction pipe of the second pump;
Equipped with
When the first pump and the second pump are operated in parallel, the communication valve is closed;
the first discharge valve and the intake valve are open;
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 ;
a rotation axis of the first pump and a rotation axis of the second pump are arranged parallel to each other,
The suction or discharge portion of the second pump is configured to be curved;
a discharge pipe of the first pump extending in the same direction as a rotation axis of the first pump;
A position of a suction portion or a pump casing of the second pump to which the connecting pipe is connected is provided at a position farther from an impeller of the first pump in a discharge direction of the discharge pipe of the first pump than a position where the connecting pipe is connected to the discharge pipe of the first pump.
Drainage system. a second discharge valve provided in a discharge pipe of the second pump;
When the first pump and the second pump operate in series or parallel, the second discharge valve is open.
2. The drainage system of claim 1. A control method for transitioning from parallel operation to series operation in the drainage system according to claim 2 , comprising the steps of:
closing the first discharge valve and the second discharge valve;
fully opening the communication valve;
fully closing the intake valve;
fully opening the second discharge valve;
The control method includes: