JP6469384B2 - Advance standby pump - Google Patents

Description

  The present invention relates to a preceding standby type pump used for draining rainwater or the like.

  In recent years, when abnormal weather such as sudden torrential rains frequently occurs, the demand for a prior standby pump is increasing as a pump installed in a pump station for draining rainwater flowing from a rainwater main line. The preceding standby type pump is a pump capable of rotating an impeller in advance at a predetermined rotation speed regardless of the water level in the suction water tank in order to quickly pump the water in the suction water tank. That is, the preceding standby type pump is a pump that can be operated in a state where water is not in contact with the impeller or the underwater bearing (dry state).

  According to the preceding standby type pump, the operation of the pump can be started before rainwater flows into the suction water tank. Therefore, even if the rainwater flowing into the suction tank suddenly increases due to sudden torrential rain, there is no delay in the pump drainage due to delays in operation or start-up failure, and water is quickly discharged from the suction tank. It is possible to prevent inundation damage due to drainage and drainage delay.

  An example of a conventional advance standby pump is shown in FIG. FIG. 14 is a schematic cross-sectional view of a conventional advance standby pump. The preceding standby pump shown in FIG. 14 includes an impeller casing 101 having a suction bell mouth 101a and a pump bowl 101b, a suspension pipe 102 that suspends the impeller casing 101 in a suction water tank 130, and an upper end of the suspension pipe 102. A discharge curved pipe 103 connected, a discharge pipe 104 connected to the discharge side of the discharge curved pipe 103, an impeller 110 housed in the impeller casing 101, a rotating shaft 115 to which the impeller 110 is fixed, And a driving machine 125 for rotating the rotating shaft 115. The rotating shaft 115 is rotatably supported by the underwater bearing 117, the intermediate bearing 118, and the outer bearing 119. The suction bell mouth 101 a is open in the suction water tank 130. The discharge side end of the discharge pipe 104 opens into the discharge water tank 131, and a backflow prevention valve (flap valve) 123 that prevents the backflow of water from the discharge water tank 131 is provided at the discharge side end. ing. The discharge pipe 104 is provided with an electric discharge valve 124, and is configured such that the discharge valve 124 is opened when the preceding standby pump is activated.

  A through hole 101c is formed in the suction bell mouth 101a at a position lower than the impeller 110, and an air inflow pipe 140 is connected to the through hole 101c. The air inflow tube 140 extends substantially horizontally from the through hole 101c and then extends upward. The air inflow pipe 140 extends to a position higher than the maximum operating water level (HWL) of the preceding standby pump, and opens to the atmosphere at a position higher than the maximum operating water level.

  In the standby standby pump, the impeller 110 is rotated and the standby operation is started in a state where the water level in the suction water tank 130 is low or in the state where there is no water in the suction water tank 130. At the start of the standby operation, the preceding standby pump is operated in an in-air operation state in which only the air flowing from the suction bell mouth 101a is sucked. When the water level rises due to the flow of water into the suction tank 130 and reaches the air-water mixing operation water level (for example, the lowest end position of the impeller 110: LL.W.L), the pumping action by the impeller 110 occurs. Thus, an air-water mixing operation state in which the water sucked from the suction bell mouth 101a and the air flowing from the air inflow pipe 140 are sucked at the same time is set. In the air-water mixing operation state, water is discharged into the discharge water tank 131 with a low flow rate. After entering the air-water mixing operation state, as the water level rises, the air suction amount from the air inflow pipe 140 decreases, and the drainage flow rate increases. When the water level reaches the operation minimum water level (LWL) of the preceding standby type pump, the flow of air from the air inflow pipe 140 is stopped, and the operation shifts to a normal drainage operation in which only water is discharged. The “operating minimum water level” in the present specification represents the minimum water level in the normal drainage operation state without the air / water mixing operation state and the air lock operation state described later.

  When the preceding standby pump discharges water to the discharge water tank 131, the water level of the suction water tank 130 decreases, and when the water level falls below the lowest operating water level (LWL), air flows from the air inlet pipe 140. Inflow starts, and it shifts to the air-water mixing operation state. When the water level further decreases and reaches the airlock water level (LLL.W.L), an air pool is formed below the impeller 110 (primary side), and water above the impeller 110 (secondary side) The operation shifts to an airlock operation state in which the impeller 110 is agitated. In the airlock operation state, the water on the secondary side of the impeller 110 is only stirred by the impeller 110 and water is not discharged into the discharge water tank 131. When the water flows into the suction water tank 130 and the water level rises, the operation again moves to the air / water mixing operation state. In the airlock operation state, water on the secondary side of the impeller 110 is gradually returned into the suction water tank 130 through a gap between the impeller 110 and the impeller casing 101 and the like. When the water on the secondary side of the impeller 110 runs out, the preceding standby pump shifts from the air lock operation state to the air operation state.

  Conventionally, the preceding standby type pump operated in such a cycle has been a facility (for example, 20 m or less) in which the total pump head is relatively small. However, with the recent urbanization, the rainwater main line has been buried at a very deep position (large depth). For this reason, there is an increasing demand for a deep standby type pump with a large total head. The total head of the advanced standby pump that is required is at least 30 m or more, and a total head of 50 m or more may be required.

  When a preceding standby pump with a large total head is installed at a large depth, it is necessary to extend the discharge pipe communicating with the discharge water tank very long in the vertical direction. When the discharge pipe is lengthened, the time in the air / water mixing operation state and the air lock operation state becomes longer as the length of the discharge pipe increases. The air / water mixing operation state and the air lock operation state are the most unstable operation states in which large vibrations are generated in the pump. Therefore, if the air / water mixing operation state and the air lock operation state continue for a long time, a failure of the equipment constituting the preceding standby pump occurs, or the civil engineering enclosure in which the preceding standby pump is installed is adversely affected.

  Further, in the air lock operation state, the preceding standby type pump is in a state where the water in the discharge pipe is agitated with no water being fed. In this case, since most of the power of the pump is consumed as heat, the water temperature in the discharge pipe rises, which may adversely affect the devices constituting the preceding standby pump. Furthermore, the discharge pipe is thermally expanded, and the load on the civil engineering enclosure supporting the discharge pipe is increased.

  Furthermore, a conventional advance standby type pump generally employs a simple flap valve (see reference numeral 123 in FIG. 14) as a mechanism for preventing the backflow of water from the discharge water tank. In such a flap valve, the valve body is required to have a strength higher than the actual lift difference (= discharge water tank water level−suction water tank water level). However, the flap valve having a simple structure has a problem in that it is difficult to design and respond (manufacture) with a difference in the high actual head height which is a large depth.

  Further, in the case of a flap valve, a phenomenon (so-called slamming phenomenon) that the valve body closes in an impact manner occurs due to the valve body being delayed in closing with respect to the reverse flow when the pump is stopped. When the slamming phenomenon occurs, a large impact sound is generated and there is a risk that the valve body and / or the valve body may be damaged. In addition, when the slamming phenomenon occurs, an impact is transmitted to the civil engineering enclosure where the flap valve is installed, and the civil engineering enclosure may be damaged. As countermeasures against this phenomenon, countermeasures such as adopting a quick closing type or forced slow closing type flap valve can be considered, but since the flap valve is a device that is submerged in the discharge water tank, such a special structure is adopted. It is difficult to adopt.

  Furthermore, if the stand-by type pump has a high head, a water hammer phenomenon occurs when the pump stops suddenly (for example, when a trip occurs due to a power failure or failure, etc.), and the pressure drop or rise associated with the occurrence of the water hammer phenomenon also occurs. growing. In order to suppress the pressure change caused by the water hammer phenomenon, a mechanism for releasing the pressure for the designed time is required. However, since it is difficult for the flap valve to adopt a special structure as described above, it is not possible to take measures against the water hammer phenomenon.

  In consideration of the above-described points, in general, a pump unit with a high head is provided with a slowly-closing check valve in the middle of the discharge pipe instead of a flap valve. However, when a slow check valve is used for a high-lift pump, there is a problem with strength in the valve body of the slow check valve and the slow-close mechanism (for example, hydraulic mechanism). Then, measures such as dividing the valve body to be slowly closed and making the small valve body to be slowly closed are taken. However, in a prior standby type pump that handles sewage, rainwater, or river water, if the valve body is reduced in size, problems such as dust clogging occur. For this reason, it is difficult to employ a slowly closed check valve in a high-preceding standby standby pump.

  If a check valve is provided in the middle of the discharge pipe, water remains on the secondary side of the check valve in the discharge pipe that rises vertically after the pump is stopped. Since the preceding standby type pump is operated in rainy weather, in some cases, the residual water on the secondary side of the check valve may be left as it is for days or weeks. The leftover water will rot and generate a strange odor. In addition, when the septic water left in the next operation is discharged to a discharge-side river or the like, there is a concern about the deterioration of the water quality of the river and the impact on the ecosystem.

Japanese Utility Model Publication No. 7-17987 JP 2007-85065 A JP-A-11-141709

  This invention is made | formed in view of the said situation, and it aims at providing the advance stand-by type pump which can shorten the time of an air-lock driving | running state. It is another object of the present invention to provide a pre-standby pump that effectively takes measures against slamming and water hammer.

One aspect of the present invention for solving the above-described problems is an impeller that is housed in an impeller casing and sucks water in a suction tank, a drive device that rotates the impeller, and the impeller casing. A pumped pipe for transferring the water sucked in by the impeller to the discharge water tank, a flap valve provided at the opening end of the pumped pipe, branched from the pumped pipe, and communicated with the suction water tank A return pipe, an open / close valve provided in the return pipe, and a control unit that controls the open / close operation of the open / close valve, and the pumping pipe is suspended from the impeller casing in the suction water tank. A discharge pipe connected to an upper end of the suspension pipe, and a discharge pipe connected to a discharge side of the discharge bent pipe, and the return pipe branches from the discharge pipe. and which the control unit, the Based on the water level in the water tank and the pressure or flow rate in the pumping pipe, it is determined whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state, and the control unit is configured to perform the preceding standby operation. When it is determined that the mold pump is in the air-lock operation state, the control unit is a preceding standby pump characterized by opening the on-off valve.

In a preferred aspect of the present invention, the control unit is configured such that the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the pressure or flow rate in the pumping pipe is a predetermined set value. In the following cases, it is determined that the preceding standby pump is in an air-lock operation state.
In a preferred aspect of the present invention, the control unit is configured such that the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the pressure or flow rate in the pumping pipe is a predetermined set value. If it is larger than the above, it is determined that the preceding standby pump is in the air-water mixing operation state.
In a preferred aspect of the present invention, when emphasizing avoidance of an unstable state of the preceding standby pump, when the control unit determines that the preceding standby pump is in a gas-water mixing operation state, the control is performed. The part is characterized by opening the on-off valve.
Another aspect of the present invention is an impeller housed in an impeller casing for sucking water in a suction water tank, a drive unit for rotating the impeller, and connected to the impeller casing. A pumping pipe for transferring the sucked water to the discharge water tank, a flap valve provided at an open end of the pumping pipe, a return pipe branched from the pumping pipe and communicating with the suction water tank, and the return An open / close valve provided in the pipe, and a control unit that controls the open / close operation of the open / close valve, the control unit preceding the water level in the suction water tank and the pressure or flow rate in the pumping pipe When determining whether the standby pump is in the air-water mixing operation state or the air lock operation state, and when the control unit determines that the preceding standby pump is in the air lock operation state, the control unit The above The valve is opened, and the control unit is a case where the water level in the suction water tank is lower than the operation minimum water level and higher than the airlock water level, and the pressure or flow rate in the pumping pipe is higher than a predetermined set value. When it is larger, the preceding standby pump determines that the preceding standby pump is in the air-water mixing operation state.

Still another aspect of the present invention is an impeller that is housed in an impeller casing and sucks water in a suction water tank, is connected to a drive unit that rotates the impeller, and the impeller casing. A pumping pipe for transferring the water sucked by the discharge water tank, a discharge valve provided in the pumping pipe, a check valve provided in the pumping pipe and disposed on the primary side of the discharge valve, A return pipe branched from the pumping pipe and extending from the primary side of the check valve to the suction water tank, an on-off valve provided in the return pipe, and a bypass provided in the pumping pipe and bypassing the check valve A pipe, a bypass valve provided in the bypass pipe, and a control unit that controls the on-off valve and the opening / closing operation of the bypass valve, wherein the control unit includes a water level in the suction water tank, and the check Flow provided in the valve Based on the flowing water detection signal of the detector, it is determined whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state, and the control unit determines whether the preceding standby pump is in the air lock operation state. If it is determined that there is, the control unit opens the on-off valve and closes the bypass valve.

In a preferred aspect of the present invention, the control unit is a case where the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the water flow detector transmits a water flow detection signal. If not, it is determined that the preceding standby pump is in an airlock operation state.
In a preferred aspect of the present invention, the control unit is a case where the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the water flow detector transmits a water flow detection signal. When it is, it is judged that the preceding standby type pump is in the air-water mixing operation state.
In a preferred aspect of the present invention, when emphasizing avoidance of an unstable state of the preceding standby pump, when the control unit determines that the preceding standby pump is in a gas-water mixing operation state, the control is performed. The part is characterized by opening the on-off valve and the bypass valve.
A preferred aspect of the present invention further comprises a drain pipe branched from the pumping pipe and extending from the secondary side of the discharge valve to the suction water tank, and a drain valve provided in the drain pipe, The drain valve is opened after the preceding standby pump stops.

According to the present invention, when the control unit determines that the preceding standby pump is in the air lock operation state, the control unit opens the on-off valve. Thereby, the water which exists in the secondary side of an impeller can be efficiently returned to a suction water tank through a return pipe. As a result, the air lock operation time is shortened, and the preceding standby pump can shift to the air operation state, which is a relatively stable operation state, in a short time.
Further, according to the present invention, even if the water pressure on the secondary side of the check valve becomes high at the time of emergency stop such as a power failure or a pump failure, the water is passed from the secondary side of the check valve to the primary side through the bypass pipe. By making it flow backward, pressure can be relieved. Therefore, it is possible to prevent a slamming phenomenon or a water hammer phenomenon that occurs during an emergency stop such as a power failure or a pump failure.

It is a schematic sectional drawing which shows the advance stand-by type pump which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the advance stand-by type pump of a driving | running state in air. It is a schematic sectional drawing of the advance stand-by type pump of a gas-water mixing operation state. It is a schematic sectional drawing of the advance stand-by type pump of a normal drain operation state. It is a schematic sectional drawing of the advance stand-by type pump of an air lock operation state. It is an operation | movement flowchart of a prior | preceding standby type pump shown in FIG. It is a schematic sectional drawing which shows the advance stand-by type pump which concerns on another embodiment of this invention. It is an operation | movement flowchart of the advance stand-by type pump shown in FIG. An example of the check valve in which the water flow detector is arranged is shown. FIG. 9A is a plan view of the check valve in which the water flow detector is arranged, and FIG. 9B is a view in FIG. It is an AA line arrow directional view. It is an operation | movement flowchart at the time of a normal stop. It is an operation | movement flowchart at the time of emergency stop. It is a schematic sectional drawing which shows the advance stand-by type pump which concerns on another embodiment of this invention. It is a schematic sectional drawing which shows the advance stand-by type pump which concerns on another embodiment of this invention. It is a schematic sectional drawing of the conventional advance standby type pump.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a preceding standby pump according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a preceding standby pump according to an embodiment of the present invention. The preceding standby pump shown in FIG. 1 includes an impeller casing 1 having a suction bell mouth 1a and a pump bowl 1b, a suspension pipe 2 for suspending the impeller casing 1 in a suction water tank 30, and an upper end of the suspension pipe 2 A discharge curved pipe 3 connected, a discharge pipe 4 connected to the discharge side of the discharge curved pipe 3, an impeller 10 accommodated in the impeller casing 1, a rotating shaft 15 to which the impeller 10 is fixed, And a drive unit 25 for rotating the rotary shaft 15. The suspension pipe 2 extends downward through an insertion hole 7 formed in the pump installation floor 6 above the suction water tank 30 into which water (for example, rainwater) flows, and is installed at the upper end of the suspension pipe 2. It fixes to the pump installation floor 6 via. The rotating shaft 15 extends in the vertical direction through the discharge curved pipe 3, the suspension pipe 2, and the impeller casing 1. The rotating shaft 15 is rotatably supported by the underwater bearing 17, the intermediate bearing 18, and the outer bearing 19. The water boosted by the rotating impeller 10 is pumped to the discharge water tank 31 through the pumping pipe 5 composed of the suspension pipe 2, the discharge bent pipe 3, and the discharge pipe 4.

  The suction bell mouth 1a opens downward in the suction water tank 30, and the upper end of the suction bell mouth 1a is fixed to the lower end of the pump bowl 1b. The impeller 10 is fixed to the lower end of the rotating shaft 15, and the impeller 10 and the rotating shaft 15 rotate integrally. A plurality of guide vanes 16 are arranged on the secondary side (discharge side) of the impeller 10. These guide vanes 16 are fixed to the inner peripheral surface of the pump bowl 1b. The underwater bearing 17 that rotatably supports the rotating shaft 15 is accommodated in the pump bowl 1 b and is located above the impeller 10. Similarly, an intermediate bearing 18 that rotatably supports the rotary shaft 15 is accommodated in the suspension pipe 2, and an outer bearing 19 is fixed to the discharge curved pipe 3 outside the discharge curved pipe 3.

  The discharge pipe 4 includes a first horizontal part 4a, a first curved pipe part 4b, a vertical straight pipe part 4c, a second curved pipe part 4d, and a second horizontal part 4e. The first horizontal portion 4a is connected to the discharge side of the discharge curved tube 3, extends in the horizontal direction, and is connected to the first curved tube portion 4b. The first curved pipe portion 4b is bent by 90 ° and is arranged to change the extending direction of the discharge pipe 4 upward. The discharge side of the first curved pipe portion 4b is connected to the vertical straight pipe portion 4c. The vertical straight pipe portion 4c extends in the vertical direction and is connected to the second curved pipe portion 4d. The second curved pipe portion 4d is bent by 90 ° and is arranged to change the extending direction of the discharge pipe 4 horizontally. The discharge side of the second curved pipe portion 4d is connected to the second horizontal portion 4e.

  The discharge side end of the second horizontal portion 4e of the discharge pipe 4 opens into the discharge water tank 31, and a reverse flow prevention valve that prevents the back flow of water from the discharge water tank 31 is provided at the discharge side opening end. A flap valve 23 is provided. A discharge valve 24 is provided in the first horizontal portion 4 a of the discharge pipe 4. The discharge valve 24 is closed when the preceding standby pump is not operated, and is configured such that when the preceding standby pump is activated, the discharge valve 24 is opened by the control unit 28 described later. Yes. In the present embodiment, the discharge valve 24 is composed of an electric valve.

  An automatic air vent valve 80 is connected to the second curved pipe portion 4d through a pipe that opens to the second curved pipe portion 4d. Since the automatic air vent valve 80 allows the air to flow into the discharge pipe 4 when water in the discharge pipe 4 is drained, the water in the discharge pipe 4 can be smoothly drained. Time can be shortened. Instead of the automatic air vent valve 80, an air vent pipe may be provided in the second horizontal portion 4 e located in the discharge water tank 31. The air vent pipe extends to a position higher than the highest water level of the discharge water tank 31, and opens into the atmosphere at a position higher than the highest water level.

  A through hole 1c is formed in the suction bell mouth 1a at a position lower than the impeller 10, and an air inflow pipe 40 is connected to the through hole 1c. The air inflow tube 40 extends substantially horizontally from the through hole 1c and then extends upward. The air inflow pipe 40 extends to a position higher than the maximum operating water level (HWL) of the preceding standby pump, and opens into the atmosphere at a position higher than the maximum operating water level.

  The drive unit 25 and the discharge valve 24 are connected to a power distribution / control panel as the control unit 28. In response to the command issued by the control unit 28, the start and stop of the driving machine 25 are controlled. In response to a command issued by the control unit 28, the opening / closing operation of the discharge valve 24 is controlled.

  In the preceding standby type pump, in a state where the water level in the suction water tank 30 is low or in a state where there is no water in the suction water tank 30, the impeller 10 is rotated at a predetermined rotational speed by the drive unit 25 and a standby operation is started. . At the start of the standby operation, the preceding standby pump is operated in an air operation state in which only the air flowing from the suction bell mouth 1a is sucked. A schematic cross-sectional view of the preceding standby type pump in the air operation state is shown in FIG. The in-air operation state shown in FIG. 2 is a so-called idling state, and the preceding standby pump discharges only the air sucked from the suction bell mouth 1a.

  When water flows into the suction water tank 30, the water level in the suction water tank 30 rises and reaches the air-water mixing operation water level (for example, the lowest end position of the impeller 10: LL.W.L). The pumping action by No. 10 occurs, and the air-water mixing operation for simultaneously sucking up the water sucked from the suction bell mouth 1a and the air flowing from the air inlet pipe 40 is started. A schematic cross-sectional view of the preceding standby pump in the air-water mixing operation state is shown in FIG. In the air-water mixing operation state shown in FIG. 3, water is discharged into the discharge water tank 31 with a low flow rate. After the start of the air-water mixing operation, as the water level in the suction water tank 30 rises, the amount of air sucked from the air inflow pipe 40 decreases and the amount of drainage water increases. When the water level reaches the operation minimum water level (LWL) of the preceding standby type pump, as shown in FIG. 4, the inflow of air from the air inflow pipe 40 is stopped and only the water is discharged. Migrate to

  When the preceding standby type pump discharges water to the discharge water tank 31, the water level in the suction water tank 30 decreases, and when the water level falls below the lowest operating water level (LWL), The inflow of air is started, and the operation moves to the air-water mixing operation state shown in FIG. When the water level further decreases and reaches the airlock water level (LLL.W.L), an air pool is formed below the impeller 10 (primary side), and water above the impeller 10 (secondary side) The operation shifts to an airlock operation state in which the impeller 10 is agitated. FIG. 5 shows a schematic cross-sectional view of the preceding standby type pump in the air lock operation state. In the air lock operation state, water on the secondary side (discharge side) of the impeller 10 is only stirred by the impeller 10, and water is not transferred to the discharge water tank 31. When the water flows into the suction water tank 30 and the water level rises, the operation again moves to the air-water mixing operation state. In the airlock operation state, the water on the secondary side of the impeller 10 is gradually returned into the suction water tank 30 from the gap between the impeller 10 and the impeller casing 1. When water on the secondary side of the impeller 10 runs out, the preceding standby type pump shifts from the air lock operation state to the air operation state shown in FIG.

  In the embodiment shown in FIG. 1, there is further provided a return pipe 41 that is branched from the pumped water pipe 5 composed of the suspension pipe 2, the discharge bent pipe 3, and the discharge pipe 4 and communicates with the suction water tank 30. More specifically, the inlet of the return pipe 41 is connected to the first horizontal portion 4 a of the discharge pipe 4 and is located on the secondary side of the discharge valve 24. The outlet of the return pipe 41 communicates with the suction water tank 30. The return pipe 41 is provided with an open / close valve 42. The opening / closing valve 42 is connected to the control unit 28, and the opening / closing operation of the opening / closing valve 42 is controlled by the control unit 28. In the present embodiment, the on-off valve 42 is constituted by an electric valve. As the on-off valve 42, a valve operated by an actuator other than a motor such as an air cylinder may be used. In the embodiment shown in FIG. 1, the return pipe 41 is branched from the secondary side of the discharge valve 24. However, as shown by a two-dot chain line in FIG. ) May be branched. Alternatively, both the return pipe 41 branched from the primary side of the discharge valve 24 and the return pipe 41 branched from the secondary side of the discharge valve 24 may be provided. In this case, an opening / closing valve 42 whose opening / closing operation is controlled by the control unit 28 is provided in each of the two return pipes 41, 41.

  In the embodiment shown in FIG. 1, a pressure gauge 43 for measuring the pressure of water in the discharge pipe 4, that is, the pump discharge pressure is provided. The pressure gauge 43 is provided at a position for measuring the pressure of water on the primary side of the discharge valve 24. Further, a flow meter 44 for measuring the flow rate of water in the discharge pipe 4, that is, the pump discharge flow rate is provided. The flow meter 44 is provided at a position where the flow rate of water on the secondary side of the discharge valve 24 is measured. In the preceding standby type pump of the present embodiment, it is sufficient that at least one of the pressure gauge 43 and the flow meter 44 is provided. Moreover, the drive machine 25 of this embodiment is comprised from an electric motor (for example, motor), and the ammeter 47 which measures the electric current which flows into the said electric motor is further provided. Furthermore, a water level gauge 48 for measuring the water level in the suction water tank 30 is provided. The pressure gauge 43, the flow meter 44, the ammeter 47, and the water level gauge 48 are connected to the control unit 28, respectively. Each measurement value acquired by the pressure gauge 43, the flow meter 44, the ammeter 47, and the water level gauge 48 is transmitted to the control unit 28.

  In the present embodiment, the control unit 28 waits in advance based on the measured value of the pump discharge pressure, the measured value of the pump discharge flow rate, the measured value of the current flowing through the driver 25, and the measured value of the water level in the suction water tank 30. It is determined whether the mold pump is in the air operation state, the air / water mixing operation state, the air lock operation state, or the normal drainage operation state. The control unit 28 controls the opening / closing operation of the opening / closing valve 42 based on the determined operation state of the preceding standby pump. Below, the determination method of an operation state and the opening / closing operation | movement of the on-off valve 42 are demonstrated using FIG.

  FIG. 6 is an operation flowchart of the preceding standby pump shown in FIG. As shown in FIG. 6, first, an operation start command for the preceding standby pump is input to the control unit 28 (step 1). The control unit 28 to which the operation start command is input starts the operation of the driving machine 25 (step 2). At the same time, the control unit 28 issues a command to open the discharge valve 24 (step 3). Further, the air operation timer T1 starts counting (step 4). The air operation timer T1 will be described later. The control unit 28 confirms that the opening operation of the discharge valve 24 is completed by a signal (answerback signal) from the discharge valve 24 (step 5). In the flowchart shown in FIG. 6, the opening command for the discharge valve 24 is issued simultaneously with the start of the operation of the driving machine 25. However, the opening instruction for the discharge valve 24 may be issued after the activation of the driving machine 25 is completed. Good.

  Next, the control unit 28 confirms the water level of the suction water tank 30 measured by the water level gauge 48. Specifically, the control unit 28 checks whether or not the current water level is lower than the lowest operating water level (LWL) of the preceding standby pump (step 6). When the current water level is equal to or higher than the operation minimum water level (LWL), the control unit 28 determines that the preceding standby pump is in the normal drainage operation state (step 7). In this case, the control unit 28 closes the on-off valve 42 (step 8) and resets the air operation timer T1 (step 9). Thereafter, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again.

  In step 6, when the current water level is lower than the operation minimum water level (LW.L), the control unit 28 checks whether or not the current water level is higher than the airlock water level (LLL.W.L). (Step 10). When the current water level is equal to or lower than the airlock water level (LLL.W.L), the control unit 28 checks whether or not the current of the driving machine 25 measured by the ammeter 47 is equal to or higher than a set value (step). 11). When the current of the driving machine 25 is lower than the set value, the load on the impeller 10 is almost absent, so the control unit 28 determines that the preceding standby pump is in the air operation state (step 12). In this case, the control unit 28 checks whether or not the air operation timer T1 is in the reset state, and if it is in the reset state, starts the air operation timer T1 (step 13). Moreover, the control part 28 opens the on-off valve 42 (step 14). When the on-off valve 42 is opened during the air operation state, the air sucked from the suction water tank 30 by the rotation of the impeller 10 and flowing to the discharge pipe 4 is returned to the suction water tank 30 through the return pipe 41. It is. That is, a circulating air flow can be created between the preceding standby pump and the suction water tank 30. This circulating air flow cools the underwater bearing 17 and the intermediate bearing 18 that are most likely to generate heat in the air operating state. Therefore, the underwater bearing 17 and the intermediate bearing 18 can be prevented from being burned out.

  When the control unit 28 determines in step 12 that the preceding standby pump is in the air operation state, the control unit 28 checks whether or not the air operation timer T1 has reached the set time (step 15). . If the air operation timer T1 has not reached the set time, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again. If the air operation timer T1 has reached the set time, the control unit 28 stops the operation of the preceding standby pump (step 16). In the aerial operation state, there is no water that serves as a lubricant for the underwater bearing 17 and the intermediate bearing 18, and therefore the wear of the underwater bearing 17 and the intermediate bearing 18 easily proceeds. Further, the underwater bearing 17 and the intermediate bearing 18 generate heat. Accordingly, an air operation timer T1 is provided in order to prevent the life reduction and burnout of the underwater bearing 17 and the intermediate bearing 18 so that the air operation state does not continue for a certain time or more. The set time of the air operation timer T1 is, for example, 1 hour.

  If it is determined that the preceding standby pump is in the normal drain operation or is in the air / water mixture state described later, the air operation timer T1 is reset. Once the underwater bearing 17 and the intermediate bearing 18 are immersed in water, the lubrication of the underwater bearing 17 and the intermediate bearing 18 is improved, and the underwater bearing 17 and the intermediate bearing 18 are cooled. Accordingly, when the underwater bearing 17 and the intermediate bearing 18 are once immersed in water, the drainage operation of the preceding standby pump can be continued by resetting the air operation timer T1. As a result, it is possible to continue the operation of the preceding standby pump.

  If the current of the drive unit 25 is greater than or equal to the set value in step 11, the impeller 10 is in a load state, so the control unit 28 determines that the preceding standby pump is in the air / water mixture state (step 17). ). Further, when the current water level is higher than the airlock water level (LLL.W.L) in step 10, the control unit 28 determines that the preceding standby pump is in the air / water mixture state (step 17). The air / water mixing state means that the preceding standby pump is in an operation state of either the air / water mixing operation state shown in FIG. 3 or the air lock operation state shown in FIG. 5. Therefore, next, the control unit 28 determines whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state. As described above, when the preceding standby pump is in the air / water mixed state, the underwater bearing 17 and the intermediate bearing 18 are immersed in water, so the air operation timer T1 is reset (step 18).

  Next, the control unit 28 checks whether or not the pump discharge pressure measured by the pressure gauge 43 is equal to or lower than a set value (step 19). When the pump discharge pressure is larger than the set value, it indicates that water is being transferred to the discharge water tank 31, and therefore the control unit 28 determines that the preceding standby pump is in the air-water mixing operation state ( Step 20). In this case, the control unit 28 closes the on-off valve 42 (step 21). Thereafter, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again. Since the air / water mixing operation state is also an unstable operation state, the control unit 28 may issue a command to open the on-off valve 42 in step 21. Thus, when the on-off valve 42 is opened in the air / water mixing operation state, the water in the discharge pipe 4 is returned to the suction water tank 30 through the return pipe 41, so that the preceding standby pump can be operated in the air in a short time. It becomes a state. Therefore, when importance is attached to avoiding an unstable state, the control unit 28 may open the on-off valve 42.

  When the pump discharge pressure is equal to or lower than the set value, water is not transferred to the discharge water tank 31, and the impeller 10 draws water in the pumping pipe 5 (the suspended pipe 2, the discharge bent pipe 3, and the discharge pipe 4). It shows that it is only stirring. Therefore, the control unit 28 determines that the preceding standby pump is in the air lock operation state (step 22). In this case, the control unit 28 opens the on-off valve 42 (step 23). When the on-off valve 42 is opened in the air lock operation state, the water in the discharge pipe 4 quickly flows into the suction water tank 30 through the return pipe 41, so that the water present on the secondary side of the impeller 10 is sucked in a short time. The water tank 30 can be returned. As a result, the time of the air lock operation state is shortened, and the advance standby pump can shift to the air operation state which is a relatively stable operation state in a short time. After step 23, the operation flow returns to step 6, and the control unit 28 confirms the water level in the suction water tank 30 again.

  As shown in FIG. 1, the inlet of the return pipe 41 may be connected to the top and bottom surfaces of the discharge pipe 4. Alternatively, the inlet of the return pipe 41 may be connected to the upper surface, the side surface, and the bottom surface of the discharge pipe 4. By connecting a plurality of inlets of the return pipe 41 to a plurality of locations of the discharge pipe 4, it is possible to prevent dust from being entangled with the inlet of the return pipe 41 and the return pipe 41 from functioning. As a result, it is possible to provide a more reliable facility.

  Further, instead of confirming the pump discharge pressure measured by the pressure gauge 43 in step 19, the control unit 28 determines that the pump discharge flow rate (the flow rate of water flowing through the pumping pipe 5) measured by the flow meter 44 is equal to or less than the set value. It may be confirmed whether or not. If the pump discharge flow rate is greater than the set value (for example, if the pump discharge flow rate is greater than 0), it indicates that water is being transferred to the discharge water tank 31, and therefore the control unit 28 is configured to use the preceding standby pump. Is determined to be in the air-water mixing operation state (step 20). In this case, the control unit 28 closes the on-off valve 42 (step 21). As described above, the opening / closing valve 42 may be opened in step 21. If the pump discharge flow rate measured by the flow meter 44 is less than or equal to the set value (for example, if the pump discharge flow rate is 0), water is not transferred to the discharge water tank 31 and the impeller 10 It shows that the water is only stirred. Therefore, the control unit 28 determines that the preceding standby pump is in the air lock operation state (step 22). In this case, the control unit 28 opens the on-off valve 42 (step 23).

  Instead of checking the pump discharge pressure or the pump discharge flow rate in step 19, the control unit 28 may check the water level of the suction water tank 30. That is, the control part 28 confirms whether the water level of the suction water tank 30 measured by the water level gauge 48 is lower than the air-water mixing operation water level (LL.W.L) as step 19. When the water level of the suction water tank 30 is equal to or higher than the air-water mixing operation water level (LL.W.L), the control unit 28 determines that the preceding standby pump is in the air-water mixing operation state (step 20). In this case, the control unit 28 closes the on-off valve 42 (step 21). As described above, the opening / closing valve 42 may be opened in step 21. When the water level of the suction water tank 30 is lower than the air-water mixing operation water level (LL.W.L), the control unit 28 determines that the preceding standby pump is in the airlock operation state (step 22). In this case, the control unit 28 opens the on-off valve 42 (step 23). The air inflow pipe 40 is provided with means for measuring the air inflow amount, and it is determined whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state depending on the air inflow amount flowing through the air inflow tube 40. You may judge.

  FIG. 7 is a schematic cross-sectional view illustrating a preceding standby pump according to another embodiment of the present invention. In the embodiment shown in FIG. 7, a check valve 50 is provided instead of the flap valve 23 shown in FIG. 1. The check valve 50 is disposed on the primary side of the discharge valve 24 in the pumping pipe 5. In the embodiment shown in FIG. 7, the check valve 50 and the discharge valve 24 are arranged in the vertical straight pipe portion 4 c of the discharge pipe 4. Further, the return pipe 41 provided with the above-described on-off valve 42 branches off from the primary side of the check valve 50 in the pumped-up pipe 5. Further, a bypass pipe 51 that bypasses the check valve 50 is provided in the vertical straight pipe portion 4c. A bypass valve 52 is disposed in the bypass pipe 51. The bypass valve 52 is normally opened during the drainage operation. In the present embodiment, the bypass valve 52 is constituted by an electric valve. As the bypass valve 52, a valve operated by an actuator other than a motor such as an air cylinder may be used. When the pump performance (discharge amount) has a margin or when the return amount from the discharge pipe 4 is taken into consideration in the design, the bypass pipe 51 is branched from the secondary side of the check valve 50. The suction water tank 30 may be extended. Since the other configuration of the present embodiment is the same as that of the embodiment shown in FIG. 1, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 8 is an operation flowchart of the preceding standby pump shown in FIG. As shown in FIG. 8, first, an operation start command for the preceding standby pump is input to the control unit 28 (step 1). The control unit 28 to which the operation start command is input starts the operation of the driving machine 25 (step 2). At the same time, the control unit 28 issues a command to open the discharge valve 24 (step 3). Further, the air operation timer T1 starts counting (step 4). The control unit 28 confirms that the opening operation of the discharge valve 24 is completed by a signal (answerback signal) from the discharge valve 24 (step 5). In the flowchart shown in FIG. 8, the opening command for the discharge valve 24 is issued simultaneously with the start of the operation of the driving machine 25. However, the opening instruction for the discharge valve 24 may be issued after the activation of the driving machine 25 is completed. Good.

  Next, the control unit 28 confirms the water level of the suction water tank 30 measured by the water level gauge 48. Specifically, the control unit 28 checks whether or not the current water level is lower than the lowest operating water level (LWL) of the preceding standby pump (step 6). When the current water level is equal to or higher than the operation minimum water level (LWL), the control unit 28 determines that the preceding standby pump is in the normal drainage operation state (step 7). In this case, the control unit 28 closes the on-off valve 42 (step 8) and opens the bypass valve 52 (step 9). At the same time, the control unit 28 resets the air operation timer T1 (step 10). Thereafter, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again.

  Since the bypass valve 52 is opened, even if the water pressure on the secondary side of the check valve 50 becomes high at the time of emergency stop such as a power failure or a pump failure, the secondary water of the check valve 50 is passed through the bypass pipe 51. By reversing the flow from the side to the primary side, the pressure can be released. Therefore, it is possible to prevent a slamming phenomenon or a water hammer phenomenon that occurs during an emergency stop such as a power failure or a pump failure. As shown in FIG. 7, the bypass pipe 51 bypasses the check valve 50 disposed in the discharge pipe 4 and only connects the primary side and the secondary side of the check valve 50. Therefore, since the water flowing through the bypass pipe 51 during the normal drainage operation state is not returned to the suction water tank 30, even if the bypass valve 52 is opened, the performance of the pump is not reduced. In addition, when there is a margin in the performance (discharge amount) of the pump or when the return amount from the discharge pipe 4 is taken into consideration in the design of the pump, the bypass pipe 51 branches from the secondary side of the check valve 50. And you may comprise so that it may extend to the suction water tank 30.

  As the bypass valve 52, it is preferable to employ a valve such as a ball valve or an eccentric structure valve that is not easily clogged with dust. By adopting a ball valve or an eccentric structure valve, it is possible to solve the problem of dust clogging that occurs when a conventionally used slowly closed check valve is employed.

  In step 6, when the current water level is lower than the operation minimum water level (LW.L), the control unit 28 checks whether or not the current water level is higher than the airlock water level (LLL.W.L). (Step 11). When the current water level is equal to or lower than the airlock water level (LLL.W.L), the control unit 28 checks whether or not the current of the driving machine 25 measured by the ammeter 47 is equal to or higher than a set value (step). 12). When the current of the driving machine 25 is lower than the set value, the load on the impeller 10 is almost absent, so the control unit 28 determines that the preceding standby pump is in the air operation state (step 13). In this case, the control unit 28 checks whether or not the air operation timer T1 is in the reset state, and if it is in the reset state, starts the air operation timer T1 (step 14). The control unit 28 opens the open / close valve 42 (step 15) and closes the bypass valve 52 (step 16). The reason for opening the on-off valve 42 is to create a circulating air flow between the preceding standby pump and the suction water tank 30 as described above. The reason for closing the bypass valve 52 is that in the case of a pump station where a plurality of preceding standby pumps are installed, the water discharged from the other preceding standby pumps into the discharge water tank 31 flows back from the discharge water tank 31 into the discharge pipe 4. This is to prevent this. If the water discharged by other preceding standby pumps is returned to the suction water tank 30, the drainage capacity of the entire pump station will be reduced.

  In step 13, when the control unit 28 determines that the preceding standby pump is in the air operation state, the control unit 28 determines that the air operation timer T1 has reached the set time, as in the flowchart shown in FIG. It is confirmed whether or not (step 17). If the air operation timer T1 has not reached the set time, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again. If the air operation timer T1 has reached the set time, the control unit 28 stops the operation of the preceding standby pump (step 18).

  If the current of the drive unit 25 is greater than or equal to the set value in step 12, the impeller 10 is in a load state, so the control unit 28 determines that the preceding standby pump is in the air / water mixture state (step 19). ). Further, when the current water level is higher than the airlock water level (LLL.W.L) in step 11, the control unit 28 determines that the preceding standby pump is in the air / water mixture state (step 19). The air / water mixed state indicates that the preceding standby pump is in either the air / water mixed operation state shown in FIG. 3 or the air lock operation state shown in FIG. Therefore, next, the control unit 28 determines whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state. As described above, when the preceding standby pump is in the air / water mixture state, the air operation timer T1 is reset (step 20).

  Next, the control part 28 confirms whether the flowing water detector provided in the check valve 50 is detecting the flowing water in the check valve 50 (step 21). The flowing water detector provided in the check valve 50 is a device that detects whether or not the valve body of the check valve 50 is open, for example.

  FIG. 9A and FIG. 9B show an example of the check valve 50 in which the flowing water detector 70 is arranged. Fig.9 (a) is a top view of the non-return valve 50 in which the flowing water detector 70 is arrange | positioned, FIG.9 (b) is an AA arrow directional view of Fig.9 (a). FIG. 9B corresponds to an enlarged side view of the flowing water detector 70. As shown in FIG. 9A, the check valve 50 includes a valve body 71 that closes the flow path 75a of the valve body 75, and a valve shaft 72 to which the valve body 71 is fixed. The valve shaft 72 is rotatably supported by bearings 73 and 74. The valve shaft 72 extends through the bearing 73, and a cam 76 is fixed to a portion of the valve shaft 72 that extends outward from the bearing 73. When the valve shaft 72 rotates together with the valve body 71, the cam 76 also rotates together. The cam 76 is provided with a protrusion 76a. A switch 77 is provided in the vicinity of the cam 76. When the valve shaft 72 rotates in the direction in which the valve body 71 opens, the protrusion 76 a of the cam 76 contacts the switch 77. The switch 77 with which the protruding portion 76 a of the cam 76 abuts transmits an operation detection signal (that is, a flowing water detection signal) of the check valve 50, and this flowing water detection signal is sent to the control unit 28. Thus, the flowing water detector 70 can detect that the valve body 71 of the check valve 50 is opened.

  When the flowing water detection signal is sent from the flowing water detector 70, it indicates that water is being transferred to the discharge water tank 31, and therefore the control unit 28 sets the preceding standby type pump to the air-water mixing operation state. It is determined that there is (step 22). In this case, the control unit 28 closes the on-off valve 42 (step 23) and opens the bypass valve 52 (step 24). Thereafter, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again. The reason for closing the on-off valve 42 and opening the bypass valve 52 is the same reason as in the normal drainage operation state. If importance is attached to avoiding an unstable state, the on-off valve 42 may be opened in step 23 as described above.

  When no running water detection signal is sent from the running water detector 70, it indicates that the water is not transferred to the discharge water tank 31, and the impeller 10 is only stirring the water in the pumping pipe 5. Yes. Therefore, the control unit 28 determines that the preceding standby pump is in the air lock operation state (step 25). In this case, the control unit 28 opens the on-off valve 42 (step 26) and closes the bypass valve 52 (step 27).

  When the on-off valve 42 is opened in the air lock operation state, the water in the discharge pipe 4 quickly flows into the suction water tank 30 through the return pipe 41, so that it exists on the secondary side (discharge side) of the impeller 10 in a short time. The water to be returned can be returned to the suction tank 30. As a result, the time of the air lock operation state is shortened, and the advance standby pump can shift to the air operation state which is a relatively stable operation state in a short time. When the bypass valve 52 is closed in the air lock operation state, water on the secondary side (discharge side) of the check valve 50 can be prevented from flowing into the primary side (suction side) of the check valve 50. Therefore, in a shorter time, the preceding standby pump can shift to the air operation state. Even if the preceding standby type pump is in an emergency stop in the airlock operation state, the preceding standby type pump does not discharge water into the discharge water tank 31, and therefore, no slamming phenomenon or water hammer phenomenon occurs. Accordingly, the bypass valve 52 can be closed. After step 27, the operation flow returns to step 6, and the control unit 28 confirms the water level of the suction water tank 30 again.

  In step 21, instead of confirming the flowing water detection signal from the flowing water detector 70, the control unit 28 determines the pump discharge pressure measured by the pressure gauge 43, the pump discharge flow rate measured by the flow meter 44, or the water level gauge 28. You may confirm the water level of the suction tank 30 measured by. As described above, it can be determined from the pump discharge pressure, the pump discharge flow rate, or the water level of the suction water tank 30 whether the preceding standby pump is in the air / water mixing operation state or in the air lock operation state. . Further, a means for measuring the air inflow amount is provided in the air inflow pipe 40, and whether the preceding standby pump is in the air-water mixing operation state or the air lock operation state is determined by the air inflow amount flowing through the air inflow tube 40. You may judge.

  Next, the stop operation of the preceding standby pump will be described with reference to FIGS. 10 and 11. FIG. 10 is an operation flowchart during a normal stop, and FIG. 11 is an operation flowchart during an emergency stop.

  As shown in FIG. 10, in the normal stop operation, an operation stop command for the preceding standby pump is first input to the control unit 28 (step 1). The control unit 28 to which the operation stop command is input issues a close command for the discharge valve 24 (step 2). The control unit 28 confirms that the closing operation of the discharge valve 24 is completed by a signal (answerback signal) from the discharge valve 24 (step 3). Thereafter, the operation of the driving machine 25 is stopped by the control unit 28 (step 4), and the on-off valve 42 is closed (step 5). When the bypass valve 52 is provided as in the embodiment shown in FIG. 7, the bypass valve 52 is also closed by the control unit 28 (step 6).

  At the time of an emergency stop such as a power failure or a pump failure, a pump emergency stop signal is input to the control unit 28 as shown in FIG. 11 (step 1). The control unit 28 to which the emergency stop signal is input stops the operation of the driving machine 25 (Step 2) and closes the discharge valve 24 (Step 3). At the same time, the timer T2 for the on-off valve 42 starts counting (step 4). When the timer T2 reaches the set time (step 5), the on / off valve 42 is closed by the control unit 28 (step 6). When the bypass valve 52 is provided as in the embodiment shown in FIG. 7, the timer T2 for the bypass valve 52 starts counting at the same time as the timer T2 starts counting (step 7). When the timer T3 reaches the set time (step 8), the bypass valve 52 is closed by the control unit 28 (step 9).

  The set time of the timer T3 is a time during which the pressure increase due to the water hammer phenomenon can be suppressed. As this set time, it is preferable to use a time determined in advance by simulation or the like. In this way, the bypass valve 52 is closed after the discharge valve 24 is closed by a set time of the timer T3, so that an increase in pressure due to the water hammer phenomenon can be prevented. According to this embodiment, the timer T3 can easily set the gradual closing time, which was difficult to set by the gradual closing check valve using the conventional hydraulic mechanism.

  FIG. 12 is a schematic cross-sectional view showing a preceding standby pump according to still another embodiment of the present invention. In the embodiment shown in FIG. 12, the check valve 50 and the discharge valve 24 are arranged in the first horizontal portion 4a. Further, a drain pipe 60 branched from the discharge pipe 4 on the secondary side of the discharge valve 24 and communicating with the suction water tank 30 is provided, and a drain valve 61 is provided in the drain pipe 60. The inlet of the drain pipe 60 is connected to the first horizontal portion 4 a and is located on the secondary side of the discharge valve 24. The outlet of the drain pipe 60 communicates with the suction water tank 30. In the present embodiment, the drain valve 61 is constituted by an electric valve. As the drain valve 61, a valve operated by an actuator other than a motor such as an air cylinder may be used. Since the other configuration of the present embodiment is the same as that of the embodiment shown in FIG. 7, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  A drain valve 61 provided in the drain pipe 60 is connected to the control unit 28. When the preceding standby pump is operated, that is, when the drive unit 25 is operated and the discharge valve 24 is open, the drain valve 61 is closed. The control unit 28 controls the opening / closing operation of the drain valve 61 so that the drain valve 61 is opened when the preceding standby pump is stopped, that is, when the drive unit 25 is stopped and the discharge valve 24 is closed. .

  Thus, when the standby standby pump is stopped, if the drain valve 61 is opened, the residual water on the secondary side of the discharge valve 24 can be returned to the suction water tank 30, and the bad odor due to the residual water, the river The problem of water quality deterioration and ecosystem impact can be solved. The control unit 28 may automatically control the drain valve 61 so that the drain valve 61 is opened after a predetermined time has elapsed since the preceding standby pump stopped. In a pump station where a plurality of preceding standby pumps are arranged, the drain valve 61 is opened on condition that all the preceding standby pumps are stopped. By controlling in this way, the backflow to the suction | inhalation water tank 30 of the water which the other prior standby type pumps discharged to the discharge water tank 31 is prevented. For the same reason, the control unit 28 controls the opening / closing operation of the drain valve 61 so that the drain valve 61 is closed at the same time or before another other standby pump starts operation. The drain valve 61 may be opened and closed by the operator manually operating the control unit 28.

  FIG. 13 is a schematic cross-sectional view showing a preceding standby pump according to still another embodiment of the present invention. In the preceding standby type pump shown in FIG. 13, the discharge pipe 4 is composed of only the first horizontal part 4a, and the first curved pipe part 4b, the vertical straight pipe part 4c, the second curved pipe part 4d, and the first The two horizontal portions 4e are omitted. The end of the first horizontal portion 4a opens into a discharge riser 31a provided in the discharge water tank 31, and the upper part of the discharge riser 31a is connected to the discharge upper tank 31b. That is, the discharge water tank 31 includes a discharge standing upper part 31a and a discharge upper part tank 31b, and a discharge rising upper part 31a is provided instead of the vertical straight pipe portion 4c of the embodiment shown in FIGS. Since the other configuration of the present embodiment is the same as that of the embodiment shown in FIG. 12, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As in the embodiment shown in FIG. 13, instead of the vertical straight pipe portion 4c configured as a steel pipe or cast iron pipe, a discharge standing upper portion 31b configured as a concrete frame is provided, and the discharge pipe 4 is provided in the discharge standing upper portion 31b. Can be configured to open. This configuration can also be applied to the embodiment shown in FIGS.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

DESCRIPTION OF SYMBOLS 1 Impeller casing 1a Suction bell mouth 1b Pump bowl 1c Through hole 2 Suspension pipe 3 Discharge curved pipe 4 Discharge pipe 4a 1st horizontal part 4b 1st curved pipe part 4c Vertical straight pipe part 4d 2nd curved pipe part 4e Second horizontal portion 5 Pumping pipe 6 Pump installation floor 7 Insertion hole 8 Installation base 10 Impeller 15 Rotating shaft 16 Guide vane 17 Underwater bearing 18 Intermediate bearing 19 Outer bearing 23 Backflow prevention valve 24 Discharge valve 25 Drive machine 28 Control section DESCRIPTION OF SYMBOLS 30 Suction water tank 31 Discharge water tank 31a Discharge upper part 31b Discharge upper part tank 40 Air inflow pipe 41 Return pipe 42 On-off valve 43 Pressure gauge 44 Flow meter 47 Ammeter 48 Water level gauge 50 Check valve 51 Bypass pipe 52 Bypass valve 60 Drain pipe 61 Drain valve 70 Flowing water detector 71 Valve body 72 Valve shaft 73 Bearing 74 Bearing 75 Valve body 75a Flow path 76 Cam 76a Projection 77 Switch 80 Automatic air vent valve

Claims (10)

An impeller housed in an impeller casing for sucking in water in the suction tank,
A drive for rotating the impeller;
A pumping pipe connected to the impeller casing for transferring water sucked by the impeller to a discharge water tank;
A flap valve provided at the open end of the pumping pipe;
A return pipe branched from the pumping pipe and communicating with the suction water tank;
An on-off valve provided in the return pipe;
A control unit for controlling the opening and closing operation of the on-off valve,
The pumping pipe includes a suspension pipe that suspends the impeller casing in the suction water tank, a discharge curved pipe connected to an upper end of the suspension pipe, and a discharge pipe connected to a discharge side of the discharge curved pipe. Consists of
The return pipe branches from the discharge pipe,
The control unit determines whether the preceding standby pump is in the air / water mixing operation state or the airlock operation state based on the water level in the suction water tank and the pressure or flow rate in the pumping pipe,
When the control unit determines that the preceding standby pump is in an airlock operation state, the control unit opens the on-off valve.   The control unit is a case where the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and when the pressure or flow rate in the pumping pipe is equal to or lower than a predetermined set value, 2. The preceding standby pump according to claim 1, wherein the preceding standby pump is determined to be in an air lock operation state.   The control unit, when the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and when the pressure or flow rate in the pumping pipe is higher than a predetermined set value, The preceding standby pump according to claim 1 or 2, wherein the preceding standby pump is determined to be in the air-water mixing operation state. When emphasizing the avoidance of the unstable state of the preceding standby pump, when the control unit determines that the preceding standby pump is in a gas-water mixing operation state, the control unit opens the on-off valve. The preceding standby type pump according to claim 3, wherein the preceding standby type pump is opened.   An impeller housed in an impeller casing for sucking in water in the suction tank,
  A drive for rotating the impeller;
  A pumping pipe connected to the impeller casing for transferring water sucked by the impeller to a discharge water tank;
  A flap valve provided at the open end of the pumping pipe;
  A return pipe branched from the pumping pipe and communicating with the suction water tank;
  An on-off valve provided in the return pipe;
  A control unit for controlling the opening and closing operation of the on-off valve,
  The control unit determines whether the preceding standby pump is in the air / water mixing operation state or the airlock operation state based on the water level in the suction water tank and the pressure or flow rate in the pumping pipe,
  When the control unit determines that the preceding standby pump is in an airlock operation state, the control unit opens the on-off valve,
The control unit, when the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and when the pressure or flow rate in the pumping pipe is higher than a predetermined set value, A preceding standby pump characterized by determining that the preceding standby pump is in an air-water mixing operation state. An impeller housed in an impeller casing for sucking in water in the suction tank,
A drive for rotating the impeller;
A pumping pipe connected to the impeller casing for transferring water sucked by the impeller to a discharge water tank;
A discharge valve provided in the pumping pipe;
A check valve provided on the primary side of the discharge valve provided in the pumping pipe;
A return pipe branched from the pumping pipe and extending from the primary side of the check valve to the suction water tank;
An on-off valve provided in the return pipe;
A bypass pipe provided in the pumping pipe and bypassing the check valve;
A bypass valve provided in the bypass pipe;
A control unit for controlling the opening and closing operation of the on-off valve and the bypass valve,
Based on the water level in the suction water tank and the water flow detection signal of the water flow detector provided in the check valve, the control unit determines whether the preceding standby pump is in the air / water mixing operation state or the air lock operation state. Determine if there is
When the control unit determines that the preceding standby pump is in an air-lock operation state, the control unit opens the on-off valve and closes the bypass valve. When the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the water flow detector does not send a water flow detection signal, the control unit The preceding standby type pump according to claim 6 , wherein the type pump is determined to be in an air lock operation state. When the water level in the suction water tank is lower than the lowest operating water level and higher than the airlock water level, and the water flow detector is sending a water flow detection signal, the control unit The preceding standby type pump according to claim 6 or 7 , wherein the type pump is determined to be in the air-water mixing operation state. When emphasizing avoidance of the unstable state of the preceding standby pump, when the control unit determines that the preceding standby pump is in the air-water mixing operation state, the control unit includes the on-off valve and The preceding standby type pump according to claim 8 , wherein the bypass valve is opened. A drain pipe branched from the pumping pipe and extending from the secondary side of the discharge valve to the suction water tank;
A drain valve provided in the drain pipe,
The preceding standby pump according to any one of claims 6 to 9 , wherein the control unit opens the drain valve after the preceding standby pump stops.

Images