JP2016160768A - Pump system, pump system operation method and pump system modification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump system that inhibits drastic decline in water level in a suction water tank to reduce stop frequency of pump operation by a low-cost and simple configuration or method.SOLUTION: In the pump system, a suction water tank (2) is provided with a water level gage (50), a return water pipe (30) is provided with a return water valve (31) and a valve control part (40) is provided to control the return water valve (31) according to a water level in the suction water tank (3).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pump system, a method for operating the pump system, and a method for repairing the pump system.

  Pumps such as a vertical shaft pump are used to pump rainwater stored in a water absorption tank and drain it into a river or the sea.

  The pump starts when the water level in the water absorption tank rises and becomes equal to or higher than the operating water level, and stops when the water level decreases and falls below the stop water level. When the pump is stopped, it takes time to start it again. If there is a sudden heavy rain after the pump stops, the pump may not start in time, and water may overflow from the water absorption tank. Therefore, it is desirable that the frequency of starting and stopping the pump is low.

  Therefore, conventionally, there is known a technique for controlling a rapid decrease in the water level of the water absorption tank by controlling the rotational speed of the pump and suppressing the rotational speed when the water level is low to reduce the discharge amount of the pump. However, a mechanism and equipment for controlling the number of rotations are required, and the manufacturing cost of the pump system increases.

  A prior standby type pump that performs standby operation in the air when the water level of the water absorption tank is low is known. Since the preceding standby type pump does not stop even when the water level of the water absorption tank is low, it can cope with a sudden rise in the water level of the water absorption tank. However, the preceding standby type pump has a structure in which the air-water mixing operation and the air operation are performed, so that the pump efficiency is low, and since the operation switching mechanism is provided, the manufacturing cost is high.

  Furthermore, in Patent Document 1, a water tank is provided in the middle of the discharge water channel to the discharge water tank, an overflow basin is provided in the water tank, and a pump discharge provided with a bypass water channel that guides the downstream side of the overflow basin to the water absorption tank side. A flow controller is described.

  According to the pump discharge flow control device of Patent Document 1, when the water level of the water tank rises according to the water level of the discharge water tank, a part of the water pumped up by the pump returns to the water absorption tank via the bypass water channel. Thereby, the raise of the water level of a discharge water tank can be suppressed.

  Further, Patent Document 2 describes a pump facility that includes a switching valve for opening and closing a bypass pipe, and that can perform a management operation for returning water pumped up by a pump to a water absorption tank by opening the switching valve.

JP-A-8-49687 (published on February 20, 1996) JP 2010-209872 A (published September 24, 2010)

  However, the pump discharge flow rate control device of Patent Document 1 returns a part of the water absorbed from the water absorption tank to the water absorption tank via the bypass water channel according to the water level of the discharge water tank. The water is not returned to the water absorption tank in accordance with the decrease in the temperature. Therefore, it is not possible to suppress a decrease in the water level of the water absorption tank and reduce the frequency of stopping the pump.

  Moreover, the bypass pipe of the pump equipment of patent document 2 is used at the time of management operation, and returns water to a water absorption tank by an operator opening a switching valve at the time of management operation. Therefore, in the pump equipment of patent document 2, unless an operator operates a switching valve, water cannot be returned to a water absorption tank, the fall of the water level of a water absorption tank is suppressed at the time of normal operation, and the stop frequency of a pump is reduced. It is not something that can be done.

  The present invention has been made in view of the above problems, and its object is to reduce the frequency of stopping the pump by suppressing a rapid drop in the water level of the water absorption tank with a low-cost and simple configuration or method. Another object of the present invention is to provide a pump system, a method for operating the pump system, and a method for repairing the pump system.

  In order to solve the above problems, a pump system according to aspect 1 of the present invention includes a pump for pumping water in a water absorption tank, a discharge pipe for discharging water pumped by the pump to a discharge water tank, and the discharge pipe. And a water return pipe provided so that at least a portion of the water pumped by the pump can be returned to the water absorption tank, wherein the water absorption tank is provided with a water level gauge. The water return pipe is provided with a water return valve, and includes a valve control unit that controls the water return valve in accordance with the water level of the water absorption tank.

  According to said structure, at least one part of the water absorbed from the water absorption tank can be returned to a water absorption tank by controlling a water return valve according to the water level of a water absorption tank. Thereby, the rapid fall of the water level of a water absorption tank can be suppressed by the low-cost and simple structure of the water return pipe provided with the water return valve, and a valve control part, and the stop frequency of a pump can be reduced.

  The pump system according to aspect 2 of the present invention is the pump system according to aspect 1, wherein the discharge pipe is provided with a discharge valve, and the water return pipe is branched from the discharge pipe upstream of the discharge valve. The valve control unit may be configured to control the discharge valve in accordance with the water level of the water absorption tank.

  According to said structure, the quantity of the water sent to a discharge water tank among the water pumped up from the water absorption tank can be controlled by controlling a discharge valve according to the water level of a water absorption tank. Thereby, the rapid fall of the water level of a water absorption tank can be suppressed by controlling the amount of water supplied to a discharge water tank, and the stop frequency of a pump can be reduced.

  The pump system according to aspect 3 of the present invention is the pump system according to aspect 1 or 2, wherein the additional water supply pipe branches from the discharge pipe or the water return pipe and discharges at least a part of the water pumped by the pump to the discharge water tank. The additional water supply pipe may be provided with an additional water supply valve, and the valve control unit may control the additional water supply valve according to the water level of the water absorption tank.

  According to said structure, the water in a water absorption tank can be supplied to a discharge water tank using an additional water supply pipe in addition to a discharge pipe. Thereby, when there is much inflow amount of the water to a water absorption tank, the water supply amount to a discharge water tank can be increased, and the raise of the water level of a water absorption tank can be suppressed.

  In the pump system according to aspect 4 of the present invention, in the aspect 3, the valve control unit opens the water return valve and opens the water return valve when the water level of the water absorption tank is lower than a predetermined first water level. When the additional water supply valve is fully closed and the water level in the water absorption tank is equal to or higher than the first water level and lower than the predetermined second water level, the water return valve and the additional water supply valve are fully closed, When the water level of the water tank is equal to or higher than the second water level, the water return valve may be fully closed and the additional water supply valve may be opened.

  According to said structure, when the water level of a water absorption tank is less than a 1st water level, the amount of water feeding to a discharge water tank is reduced, and when the water level of a water absorption tank is more than 1st water level and less than 2nd water level, it discharges using a discharge pipe. When the water tank is operated normally by feeding water to the water tank and the water level of the water absorption tank is equal to or higher than the second water level, water can be fed to the discharge water tank using an additional water pipe in addition to the discharge pipe. Thereby, according to the water level of a water absorption tank, an appropriate quantity of water can be sent to a discharge water tank. Therefore, while suppressing the raise of the water level of a water absorption tank, the rapid fall of the water level of a water absorption tank can be suppressed, and the stop frequency of a pump can be reduced.

  Moreover, in order to solve said subject, the operating method of the pump system which concerns on aspect 5 of this invention is the pump which pumps the water in a water absorption tank, and the discharge pipe which discharges the water pumped up by the said pump to a discharge water tank And a water return pipe that is branched from the discharge pipe and is provided so that at least a part of the water pumped up by the pump can be returned to the water absorption tank. And a water return step of returning at least a part of the water pumped up by the pump to the water absorption tank through the water return pipe according to the water level of the water absorption tank. It is characterized by being.

  According to the above operation method, depending on the water level of the water absorption tank, at least a part of the water pumped up by the pump is returned to the water absorption tank via the water return pipe, and the water level of the water absorption tank is rapidly increased. The decrease can be suppressed and the pump stop frequency can be reduced.

  In the operation method of the pump system according to aspect 6 of the present invention, in the aspect 5, the pump system branches from the discharge pipe or the water return pipe, and at least a part of the water pumped by the pump is supplied to the discharge water tank. An additional water supply pipe provided so as to be able to discharge, and according to the water level of the water absorption tank, at least part of the water pumped up by the pump is discharged to the discharge water tank via the additional water supply pipe In the water return step, the water return amount is increased as the water level of the water absorption tank is decreased, and in the additional water supply step, the discharge amount is increased as the water level of the water absorption tank is increased. It may be a method.

  According to said operating method, the water in a water absorption tank can be supplied to a discharge water tank using an additional water supply pipe in addition to a discharge pipe. Thereby, according to the water level of a water absorption tank, the amount of water supply to a discharge water tank can be increased, and the raise of the water level of a water absorption tank can be suppressed.

  Furthermore, the amount of returned water can be increased as the water level in the water absorption tank decreases. Thereby, the fall of the water level of a water absorption tank can be suppressed.

  By these two operations, the water level of the water absorption tank can be stabilized.

  Moreover, in order to solve said subject, the improvement method of the pump system which concerns on aspect 7 of this invention is the pump which pumps the water in a water absorption tank, and the discharge pipe which discharges the water pumped up by the said pump to a discharge water tank And a method of revising the pump system comprising: a step of branching the discharge pipe into the discharge pipe and introducing the return pipe to the water absorption tank and having a water return valve; and a water level of the water absorption tank. And a step of installing a valve control unit for controlling the water return valve according to the method.

  According to the above modification method, by renovating the existing pump system, a rapid reduction in the water level of the water absorption tank is suppressed by a low-cost and simple configuration of a water return pipe provided with a water return valve and a valve control unit. The pump system can reduce the frequency of stopping the pump.

  A method for refurbishing a pump system according to aspect 8 of the present invention includes the additional water supply valve that is branched in the discharge pipe or the water return pipe and led to the discharge water tank and can be controlled by the valve control unit. A step of providing an additional water pipe may be included.

  According to the above modification method, the existing pump system can be modified to increase the amount of water supplied to the discharge water tank when the amount of water flowing into the water absorption tank is large, thereby increasing the water level of the water absorption tank. It can be set as the pump system which can be controlled.

  ADVANTAGE OF THE INVENTION According to this invention, the pump system which reduced the stop frequency of the pump by suppressing the rapid fall of the water level of a water absorption tank by a low-cost and simple structure or method, the operating method of a pump system, and a pump system Refurbishment methods can be provided.

It is a side view which shows the structure of the principal part of the pump system which concerns on Embodiment 1 of this invention. It is a figure which shows the operating method of the pump system which concerns on Embodiment 1 of this invention, (a) is a figure which shows the relationship between the water level of a water absorption tank, and control of a water return valve, (b) is each water level. It is a table | surface which shows the open / close state of the valve | bulb in. It is a pump system curve for demonstrating the operating characteristic of the pump system which concerns on Embodiment 1 of this invention. It is a side view which shows the structure of the principal part of the pump system which concerns on Embodiment 2 of this invention. It is a figure which shows the operating method of the pump system which concerns on Embodiment 2 of this invention, (a) is a figure which shows the relationship between the water level of a water absorption tank, and control of a water return valve, (b) is each water level. It is a table | surface which shows the open / close state of the valve | bulb in. It is a pump system curve for demonstrating the operating characteristic of the pump system which concerns on Embodiment 2 of this invention. It is a top view which shows the branch part of the return pipe and additional water supply pipe of a pump system, (a) is a top view which shows the branch part of the water return pipe and additional water supply pipe of Embodiment 2, (b) is Embodiment 3. It is a top view which shows the branch part of this water return pipe and an additional water supply pipe, (c) is a top view which shows the other example of the water return pipe of Embodiment 3, and the branch part of an additional water supply pipe.

Embodiment 1
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

<Configuration of pump system>
FIG. 1 is a side view illustrating a configuration of a main part of the pump system according to the present embodiment.

  The pump system 1 is for draining the water in the water absorption tank 2 to the outside. In the following description, the pump system 1 that supplies water in the water absorption tank 2 to the discharge water tank 3 will be described.

  The pump system 1 includes a pump 10 for pumping water in the water absorption tank 2 through a bell mouth 11, a discharge pipe 20 for discharging water pumped by the pump 10 to a discharge water tank 3, and a return pipe branched from the discharge pipe 20. 30, a valve control unit 40, and a water level meter 50 for detecting the water level of the water absorption tank 2.

  For example, a vertical shaft pump can be used as the pump 10.

  The tip of the water return pipe 30 is open to the water absorption tank 2, whereby the water return pipe 30 can return at least part of the water pumped up by the pump 10 to the water absorption tank 2. In addition, when the management operation piping used at the time of the management operation is provided, the management operation piping may also be used as the water return pipe 30.

  A discharge valve 21 is provided in the discharge pipe 20. Further, the water return pipe 30 is provided with a water return valve 31. The discharge valve 21 and the water return valve 31 only need to be able to adjust the flow rates of the discharge pipe 20 and the water return pipe 30, respectively, and various types of conventionally known types can be used. The water return pipe 30 branches from the discharge pipe 20 at a branch portion 32 on the upstream side of the discharge valve 21.

  The valve control unit 40 controls the water return valve 31 according to the water level of the water absorption tank 2 detected using the water level gauge 50. Further, the valve control unit 40 may control the discharge valve 21 according to the water level of the water absorption tank 2. The valve control unit 40 may be configured to control the pump 10, or another control unit (not shown) may be configured to control the pump 10.

  The specific configuration of the water level meter 50 is not particularly limited, and may be any type of water level meter such as a frict type water level meter, an electrode type water level meter, and a pressure type water level meter, Any of continuous measurement type water level meters may be used, but a continuous measurement type throwing water level meter which is a general water level meter can be suitably used.

<Operation of pump system>
FIG. 2 is a diagram illustrating an operation method of the pump system of the present embodiment, (a) is a diagram illustrating a relationship between the water level of the water absorption tank and the control of the water return valve, and (b) is a diagram illustrating each water level. It is a table | surface which shows the open / close state of the valve | bulb in.

  When the amount of water supplied to the discharge water tank 3 is larger than the amount of water flowing into the water absorption tank 2, the water level of the water absorption tank 2 decreases.

  In the pump system 1, the valve control unit 40 opens the water return valve 31 when the water level of the water absorption tank 2 becomes low, and returns water to the water absorption tank 2 through the water return pipe 30.

  Hereinafter, the operation method of the pump system 1 will be specifically described.

  The operation method of the pump system 1 first detects the water level of the water absorption tank 2 using the water level meter 50 (detection step). And according to the detected water level, at least one part of the water pumped up by the pump 10 is returned to the water absorption tank 2 through the water return pipe 30 (water return step).

  Specifically, as shown in FIG. 2, the valve controller 40 opens the water return valve 31 below the water level h1, and closes the water return valve 31 above the water level h2.

  Further, the valve control unit 40 maintains the water return valve 31 in the closed state when the water level in the water absorption tank 2 falls from the level h2 or higher and enters the range C, and the water level in the water absorption tank 2 is equal to or lower than the water level h1. When it rises from and enters the range of C, the water return valve 31 is kept open. That is, in the C range between the water level h1 and the water level h2, the open / close state of the water return valve 31 differs depending on whether the water level is rising or falling.

  By controlling the water return valve 31 in this way, the pump system 1 returns at least a part of the water pumped up by the pump 10 to the water absorption tank 2 according to the water level of the water absorption tank 2.

  By opening the water return valve 31, at least part of the water pumped from the water absorption tank 2 by the pump 10 is returned to the water absorption tank 2 through the water return pipe 30, so that the rotation speed of the pump 10 is controlled. Therefore, the amount of water supplied from the water absorption tank 2 to the discharge water tank 3 can be reduced by a low cost and simple configuration. Therefore, a rapid drop in the water level of the water absorption tank 2 can be suppressed, the water level of the water absorption tank 2 can be suppressed from falling below the pump stop water level, and the pump stop frequency can be reduced.

  As a result, the water level is stabilized, so that the hunting phenomenon that frequently starts and stops the pump does not occur, and when the pump 10 is driven by the engine, the time required for preparing the cooling water and the lubricating oil at the time of starting and stopping is reduced. In the case where the pump 10 is driven by a motor, it is possible to extend the life of the motor by reducing the number of times the motor is started and stopped, and to prevent a start failure due to overheating of the motor. In addition, start-up delays due to frequent pump stops can be prevented.

  In addition, as shown in FIG. 2, when the water level of the water absorption tank 2 rises to the water level h2, the water return valve 31 is closed to increase the amount of water supplied from the water absorption tank 2 to the discharge water tank 3, thereby absorbing the water. A sudden rise in the water level in the water tank 2 can be suppressed.

  The valve control unit 40 is not limited to a configuration that can control the open / close state of the water return valve 31 in two stages, that is, an open state and a closed state. For example, the valve control unit 40 may be configured to adjust the opening degree of the water return valve 31. Furthermore, the structure which can control opening and closing of each valve in conjunction with a water level and flow volume may be sufficient.

  Thereby, the amount of returned water can be adjusted according to the water level of the water absorption tank 2, the amount of returned water can be increased as the water level of the water absorption tank 2 decreases, and the water level of the water absorption tank 2 can be further stabilized. 1 can be driven.

  Further, as shown in FIG. 2B, the pump system 1 can vary the total water supply amount when the water level is rising and when the water level is falling, even if the water level is within the same water level range. Thereby, the frequency of changing the flow rate of the pump can be suppressed and a stable operation can be performed, and the frequency of opening and closing each valve can be suppressed to prevent a failure of the valve motor.

<Pump system curve>
FIG. 3 is a pump system curve for explaining the operating characteristics of the pump system of the present embodiment. In FIG. 3, the horizontal axis indicates the flow rate, and the vertical axis indicates the head.

  In FIG. 3, H represents the total head curve of the pump system 1, N <b> 1 represents the pipe resistance curve of the discharge pipe 20, N <b> 2 represents the pipe resistance curve of the discharge pipe 20 when the discharge valve 21 is throttled, N3 indicates a pipe resistance curve of the water return pipe 30, and N4 indicates a combined pipe resistance curve of the discharge pipe 20 and the water return pipe 30.

  In the conventional pump system, it is conceivable to throttle the discharge valve 21 in order to suppress a rapid drop in the water level of the water absorption tank 2. The operating point of the pump system in a state where the discharge valve 21 is throttled is P1 which is the intersection of the total head curve H and the pipe resistance curve N2. Further, the amount of water supplied to the discharge water tank 3 at this time is Q '.

  On the other hand, the operating point of the pump system 1 of the present embodiment is P2 that is the intersection of the total head curve H and the combined pipeline resistance curve N4. Moreover, the amount of water returned to the water absorption tank 2 of the pump system 1 of this embodiment is Q1, and the amount of water supplied to the discharge water tank 3 is Q2.

  As described above, in the conventional pump system, when the discharge valve 21 is throttled to suppress a rapid drop in the water level in the water absorption tank 2, the flow rate reaches, for example, 40% or less of the rating, and the pump system 1 is underflowed. It becomes driving in.

  On the other hand, when the water is returned to the water absorption tank 2 using the water return pipe 30 as in the pump system 1 of the present embodiment, the pump system 1 does not have an excessive flow rate, for example, a good amount of water slightly larger than the rated value. It is possible to drive at the operating point P2.

<Renovation of pump system>
The pump system 1 of the present embodiment may be configured by modifying an existing pump system including the pump 10 and the discharge pipe 20.

  Such a modification (renovation method) of the pump system includes a step of branching the discharge pipe 20 to the water absorption tank 2 and providing a water return pipe 30 having a water return valve 31 and a valve control for controlling the water return valve 31. And a step of installing the section 40. The existing pump system can be used as the pump system 1 of the present embodiment by a low-cost and simple repair method in which the water return pipe 30 and the valve control unit 40 are provided to the existing pump system.

  Further, in such a modification of the pump system, only the process of providing the water return pipe 30 and the valve control unit 40 may be performed, or a process of updating the pump 10 may be further included.

  In the step of installing the valve control unit 40, a function of controlling the water return valve 31 may be added to the valve control unit 40 of the existing pump system, or the valve control unit of the existing pump system is replaced with the water return valve 31. It may be replaced with a valve control unit 40 having a function of controlling

  In addition, when the management operation piping is provided in the existing pump system, it is not necessary to newly provide the water return pipe 30, and the management operation pipe may be used as the water return pipe 30. Thereby, the cost required for renovation can be suppressed.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 4 is a side view showing a configuration of a main part of the pump system of the present embodiment.

  As shown in FIG. 4, the pump system 101 includes the additional water supply pipe 60 and the pump system 1 according to the first embodiment, except that a valve control unit 140 is provided instead of the valve control unit 40. It has the same configuration.

  The additional water supply pipe 60 branches off from the discharge pipe 20 at the branch portion 32, and the tip thereof is opened to the discharge water tank 3. The additional water supply pipe 60 is provided with an additional water supply valve 61. Thereby, the additional water supply pipe 60 can discharge at least a part of the water pumped by the pump 10 to the discharge water tank 3.

  The valve control unit 140 controls the water return valve 31 and the additional water supply valve 61 according to the water level of the water absorption tank 2 detected using the water level gauge 50. Further, the valve control unit 140 may control the discharge valve 21 according to the water level of the water absorption tank 2.

<Operation of pump system>
FIG. 5 is a diagram showing an operation method of the pump system of the present embodiment, (a) is a diagram showing the relationship between the water level of the water absorption tank and the control of the water return valve, and (b) is a diagram at each water level. It is a table | surface which shows the open / close state of a valve | bulb.

  The operation method of the pump system 101 first detects the water level of the water absorption tank 2 using the water level meter 50 (detection step). And according to the detected water level, at least one part of the water pumped up by the pump 10 is discharged to the discharge water tank 3 through the additional water supply pipe 60 (additional water supply step).

  As shown to (a) of FIG. 5, the valve | bulb control part 140 will open the water return valve 31 when the water level of the water absorption tank 2 falls to the water level h3. Thereafter, the valve control unit 140 closes the water return valve 31 when the water level of the water absorption tank 2 rises to the water level h4, and opens the additional water supply valve 61 when the water level of the water absorption tank 2 rises to the water level h6. State. Thereafter, the valve control unit 140 closes the additional water supply valve 61 when the water level of the water absorption tank 2 is lowered to the water level h5.

  In this way, the valve control unit 140 controls each valve by giving hysteresis to the threshold of the water level. Thereby, chattering due to valve opening and closing can be prevented, and the frequency with which the flow rate of the pump changes can be reduced.

  As shown in (b) of FIG. 5, the valve control unit 140 is in a water level range C where the water level of the water absorption tank 2 rises from the water level h3 or lower and is higher than the water level h3 and lower than the water level h4 (lower than the first water level). The water return valve 31 is opened and the additional water supply valve 61 is fully closed. Thereby, a part of the water pumped by the pump 10 is sent to the discharge water tank 3 through the discharge pipe 20, while the other part is returned to the water absorption tank 2 through the water return pipe 30. Therefore, the amount of water supplied from the water absorption tank 2 to the discharge water tank 3 can be reduced.

  Further, the valve control unit 140 is configured so that the water return valve 31 and the additional water supply valve 61 are in the water level range B where the water level of the water absorption tank 2 is the water level h4 or higher (first water level or higher) and lower than the water level h5 (less than the second water level). Is fully closed. Thereby, all the water pumped up by the pump 10 is sent to the discharge water tank 3 through the discharge pipe 20. Therefore, the amount of water supplied from the water absorption tank 2 to the discharge water tank 3 is larger than that in the water level range C. In addition, even when the water level of the water absorption tank 2 is in the water level range B, when sudden rainwater inflow is predicted due to heavy rain in the upstream of the pump station, or when the water level increase rate is high, The additional water supply valve 61 may be opened.

  Further, the valve control unit 140 opens the additional water supply valve 61 when the water level rises above the water level h5 and becomes equal to or higher than the water level h6. Thereby, since the water pumped up by the pump 10 is sent to the discharge water tank 3 through the discharge pipe 20 and the additional water supply pipe 60, the total water supply amount from the water absorption tank 2 to the discharge water tank 3 is in the water level range B. More than

  Next, when the water level falls from the water level h6 and is in the water level range A that is higher than the water level h5 (second water level or higher) and lower than the water level h6, the water return valve 31 is fully closed and the additional water supply valve 61 is opened. And

  According to the configuration of the pump system 101 of the present embodiment, an appropriate amount of water can be supplied to the discharge water tank 3 according to the three levels of the water absorption tank. Therefore, while suppressing the raise of the water level of the water absorption tank 2, the rapid fall of the water level of the water absorption tank 2 can be suppressed, it can suppress that the water level of the water absorption tank 2 falls below a pump stop water level, and the stop frequency of a pump Can be reduced.

  As a result, the water level is stabilized, so that the hunting phenomenon that frequently starts and stops the pump does not occur, and when the pump 10 is driven by the engine, the time required for preparing the cooling water and the lubricating oil at the time of starting and stopping is reduced. In the case where the pump 10 is driven by a motor, it is possible to extend the life of the motor by reducing the number of times the motor is started and stopped, and to prevent a start failure due to overheating of the motor. In addition, start-up delays due to frequent pump stops can be prevented.

  Further, as shown in FIG. 5B, the pump system 101 can vary the total amount of water delivered when the water level rises and when the water level falls even if the water level is within the same water level range. Thereby, the frequency of changing the flow rate of the pump can be suppressed and a stable operation can be performed, and the frequency of opening and closing each valve can be suppressed to prevent a failure of the valve motor.

  In addition, the operation method of the pump system 101 of this embodiment is not limited to the operation method mentioned above. For example, when the water level of the water absorption tank 2 is low, the valve control unit 140 closes the discharge valve 21 of the discharge pipe 20 and performs water supply and water return using the additional water supply pipe 60 and the water return pipe 30. Good.

  Further, the valve control unit 140 is not limited to a configuration that can control the open / closed state of the water return pipe 30 and the additional water supply valve 61 in two stages of an open state and a closed state. For example, the valve control unit 140 may be configured to adjust the opening degree of the water return pipe 30 and the additional water supply valve 61.

  Thereby, the amount of water returned through the water return pipe 30 can be increased as the water level of the water absorption tank 2 decreases, and the amount of discharge through the additional water supply pipe 60 can be increased as the water level of the water absorption tank 2 increases. . As a result, the pump system 1 can be operated in a state in which the water supply amount (discharge amount) from the water absorption tank 2 to the discharge water tank 3 is adjusted according to the water level of the water absorption tank 2 and the water level of the water absorption tank 2 is further stabilized. it can.

  Further, the valve control unit 140 may be configured to control the valve according to the water level when the water level is measured by the water level gauge 50, or may be configured to control the valve according to the change speed of the water level. Furthermore, the structure which combined these methods may be sufficient.

<Pump system curve>
FIG. 6 is a pump system curve for explaining the operating characteristics of the pump system of this embodiment. In FIG. 6, the horizontal axis indicates the flow rate, and the vertical axis indicates the head.

  In FIG. 6, H shows the total head curve of the pump system 1, N1 shows the pipe resistance curve of the discharge pipe 20, N5 shows the pipe resistance curve of the additional water supply pipe 60, and N6 is added to the discharge pipe 20 The synthetic | combination pipe line resistance curve of the water pipe 60 is shown.

  The operating point of the conventional pump system that supplies water to the discharge water tank 3 using only the discharge pipe 20 is P3 that is the intersection of the total head curve H and the pipe resistance curve N1. Further, the amount of water supplied to the discharge water tank 3 at this time is Q3.

  On the other hand, the operating point of the pump system 101 of the present embodiment is P4, which is the intersection of the total head curve H and the combined pipeline resistance curve N6. Further, the amount of water supplied to the discharge water tank 3 of the pump system 1 of the present embodiment is the sum of the water supply amount Q4 of the discharge pipe 20 and the water supply quantity Q5 of the additional water supply pipe 60.

  As described above, in the pump system 101 of the present embodiment, since the additional water supply pipe 60 can be used to supply water to the discharge water tank 3, the total water supply amount is larger than that of a conventional pump system having only a discharge pipe. Thereby, even if it is a case where there is much inflow of the water to the water absorption tank 2, much water can be sent to the discharge water tank 3, and the raise of the water level of the water absorption tank 2 can be suppressed.

<Renovation of pump system>
The pump system 101 of the present embodiment may be configured by modifying an existing pump system including the pump 10 and the discharge pipe 20.

  Such a modification (renovation method) of the pump system includes a step of branching the discharge pipe 20 to the water absorption tank 2 and providing a water return pipe 30 provided with a water return valve 31, and a branch of the discharge pipe 20 to the discharge water tank. 3 and a step of providing an additional water supply pipe 60 provided with an additional water supply valve 61 and a step of installing a valve controller 140 capable of controlling the water return valve 31 and the additional water supply valve 61 are included.

  The existing pump system can be used as the pump system 101 of the present embodiment by a low-cost and simple modification method in which the water return pipe 30, the additional water supply pipe 60, and the valve control unit 140 are provided to the existing pump system. .

  Thereby, even if it is a case where the water level of the water absorption tank 2 becomes the water level more than the water level assumed when constructing the existing pump system, the discharge water tank 3 does not exceed the maximum capacity of the water absorption tank 2. Can be drained.

  Further, in such a modification of the pump system, only the step of providing the water return pipe 30 and the valve control unit 140 may be performed, or a step of updating the pump 10 may be further included. Such a modification of the pump system is particularly effective when the pump is replaced with a large capacity pump. That is, the amount of water pumped by the pump is increased by replacing the pump with a large-capacity pump, but the amount of water can be increased by providing the additional water supply pipe 60, so that the capacity of the pump can be utilized. Water can be supplied from the water absorption tank 2 to the discharge water tank 3. Further, by providing the water return pipe 30, it is possible to suppress a rapid drop in the water level of the water absorption tank 2 due to an increase in the capacity of the pump.

  In addition, when the management operation piping is provided in the existing pump system, it is not necessary to newly provide the water return pipe 30, and the management operation pipe may be used as the water return pipe 30. Thereby, the cost required for renovation can be suppressed.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 7 is a plan view showing a branch portion of the water return pipe and the additional water supply pipe of the pump system, (a) is a plan view showing a branch portion of the water return pipe and the additional water supply pipe of Embodiment 2, and (b). These are top views which show the branch part of the water return pipe of this embodiment, and an additional water supply pipe, (c) is a top view which shows the other example of the branch part of the water return pipe of this embodiment, and an additional water supply pipe.

  As shown to (a) of FIG. 7, in the pump system 101 of Embodiment 2, the water return pipe 30 and the additional water supply pipe 60 are branched from the discharge pipe 20 in the branch part 32 as a T-shaped pipe. That is, it can be said that the additional water supply pipe 60 is branched from the water return pipe 30.

  On the other hand, as shown in FIG. 7B, in the pump system of the present embodiment, the return pipe 30 is branched from the discharge pipe 20 at the branch section 32, and the return pipe 30 is different from the branch section 32. A different branching portion 62 branches off from the discharge pipe 20.

  Thus, the branch part of the return pipe 30 and the branch part of the additional water supply pipe 60 may be different. Moreover, although the branch part 32 is provided in the upstream (water absorption tank side) from the discharge valve 21, the branch part 62 may be upstream from the discharge valve 21, or may be downstream (discharge water tank side). ) May be provided.

  Moreover, as shown in (c) of FIG. 7, the number of additional water supply pipes is not limited to one. The pump system may include another additional water supply pipe 70 branched from the discharge pipe 20 at the branch portion 72 in addition to the additional water supply pipe 60. Thereby, the total water supply amount can be further increased.

  Further, in the pump station where a plurality of pump systems are installed, the additional water supply pipe 60 of each pump system may be shared. That is, you may provide the one additional water supply pipe 60 branched from the discharge pipe 20 of an adjacent pump system. Thereby, the installation expense of the additional water pipe 60 can be held down.

  In the second and third embodiments, the example in which the discharge pipe 20 is always used to supply water to the discharge water tank 3 has been described. However, the configuration of the present invention is not limited thereto. The discharge valve 21 of the discharge pipe 20 can be fully closed and water can be supplied only by the additional water supply pipe 60. Usually, since the diameter of the additional water supply pipe 60 is smaller than the diameter of the discharge pipe 20, if water is supplied to the discharge water tank 3 using only the additional water supply pipe 60, a smaller amount of water can be supplied, and the combination with the return pipe 30 is wider. It can be set as the pump system which can adjust the flow volume in a range.

  In addition, if there is a pump system that has been aged and stopped at a pump station with multiple pump systems, use the stopped pump system as the return pipe 30 or the additional water supply pipe 60 to reduce repair costs. You can also.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be used as a pump system for draining rainwater.

DESCRIPTION OF SYMBOLS 1,101 Pump system 2 Water absorption tank 3 Discharge water tank 10 Pump 20 Discharge pipe 21 Discharge valve 30 Return pipe 31 Return valve 40,140 Valve control part 50 Water level meter 60,70 Additional water supply pipe h4 Water level (1st water level)
h5 Water level (second water level)

Claims (8)

A pump for pumping the water in the water absorption tank;
A discharge pipe for discharging water pumped up by the pump to a discharge water tank;
A pump system that includes a return pipe that is branched from the discharge pipe and is provided so that at least a portion of the water pumped by the pump can be returned to the water absorption tank,
The water tank is provided with a water level gauge,
The return pipe is provided with a return valve,
A pump system comprising: a valve control unit that controls the water return valve in accordance with a water level of the water absorption tank. The discharge pipe is provided with a discharge valve,
The return pipe is branched from the discharge pipe upstream of the discharge valve,
The pump system according to claim 1, wherein the valve control unit controls the discharge valve in accordance with a water level of the water absorption tank. An additional water supply pipe that branches from the discharge pipe or the water return pipe and discharges at least part of the water pumped by the pump to the discharge water tank;
The additional water supply pipe is provided with an additional water supply valve,
The pump system according to claim 1 or 2, wherein the valve control unit controls the additional water supply valve in accordance with a water level of the water absorption tank.   When the water level of the water absorption tank is lower than a predetermined first water level, the valve control unit opens the water return valve and fully closes the additional water supply valve, and the water level of the water absorption tank is When the water level is equal to or higher than the first water level and lower than the predetermined second water level, the water return valve and the additional water supply valve are fully closed, and when the water level in the water absorption tank is equal to or higher than the second water level, the water return valve The pump system according to claim 3, wherein the additional water supply valve is opened while being fully closed. A pump for pumping the water in the water absorption tank;
A discharge pipe for discharging water pumped up by the pump to a discharge water tank;
A return pipe that branches off from the discharge pipe and is provided so that at least a portion of the water pumped by the pump can be returned to the water absorption tank, and a method for operating a pump system comprising:
A detection step of detecting the water level of the water absorption tank;
A water return step for returning at least a part of the water pumped by the pump to the water absorption tank through the water return pipe according to the water level of the water absorption tank. Driving method. The pump system includes an additional water supply pipe that is branched from the discharge pipe or the water return pipe, and is provided so that at least a part of the water pumped by the pump can be discharged to the discharge water tank.
According to the water level of the water absorption tank, including an additional water supply step of discharging at least part of the water pumped by the pump to the discharge water tank via the additional water supply pipe,
In the water return step, the amount of water returned is increased as the water level in the water absorption tank decreases,
6. The operation method of a pump system according to claim 5, wherein in the additional water feeding step, the discharge amount is increased as the water level of the water absorption tank increases. A pump for pumping the water in the water absorption tank;
A pump system comprising a discharge pipe for discharging water pumped up by the pump to a discharge water tank,
A step of branching the discharge pipe to the discharge tank and providing a return pipe with a return valve while branching the discharge pipe to the discharge pipe;
And a step of installing a valve control unit for controlling the water return valve in accordance with the water level of the water absorption tank.   8. The method according to claim 7, further comprising a step of branching the discharge pipe or the return pipe to lead to the discharge water tank and providing an additional water supply pipe having an additional water supply valve that can be controlled by the valve control unit. How to renovate the pump system

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