JP3937306B2 - Horizontal axis pump full water retention device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a full-water holding device for a horizontal pump capable of recovering and maintaining a full water state in a horizontal axis pump during a standby period such as a rainy period and shortening a time until drainage is started, and capable of responsive operation. .
[0002]
[Prior art]
Conventionally, an intake pipe is connected to the pump casing so that pumping operation can be started quickly, and a receiver tank is connected to the intake pipe via a pressure sensor and a vacuum breaker valve, and a vacuum pump is installed in the receiver tank. The shaft pump is known as described in, for example, Japanese Patent Application Laid-Open No. 8-270596.
[0003]
[Problems to be solved by the invention]
A conventional full water holding device for a horizontal shaft pump exhausts air from a pump casing, fills the inside of the pump with a negative pressure, and starts a pumping operation. Generally used vacuum pumps are water-sealed vacuum pumps, and the deadline operation becomes excessive vacuum pressure, which leads to damage to the drive motor. It was. In addition, when the sealed water supply is cut off during the initial operation, it becomes impossible to fill the water and the horizontal pump cannot perform the drain operation. Also, when using a scroll-type dry vacuum pump that does not require water absorption, the shut-off operation will result in excessive vacuum pressure and damage to the components, so that the shut-off operation cannot be performed and the emergency response may be delayed. It was. It is an object of the present invention to provide a full water holding device for a horizontal shaft pumping station that makes it possible to dehydrate the horizontal shaft pumping station, hold full water by continuous operation at the deadline, and can cope with an emergency.
[0004]
[Means for Solving the Problems]
The gist of the present invention is that an opening is provided in the upper part of a pump casing of a horizontal shaft pump, a full water detector and an intake valve are arranged at the base end of the intake pipe connected to the opening, and the intake pipe is In a horizontal axis pump that is connected to a vacuum pump via a receiver tank to fill the horizontal axis pump at start-up, a three-way switching valve that switches communication with the atmosphere is provided in the suction pipe connected to the receiver tank. The other end of the suction pipe is branched and connected to a dry-type vacuum pump with different capacities, and the receiver tank is sucked with a small output vacuum pump during standby of the horizontal axis pump, or the suction pipe is connected with a three-way switching valve. It is closed, and the horizontal pump is restored and held in a full state by using the negative pressure of the receiver tank. Specifically, the dry vacuum pump is a Roots pump with a different capacity. The inner surface of the vacuum pump is rust-proofed with ceramic coating or fluorine resin coating to avoid pump stop due to rusting inside the pump. In addition, a drain valve for draining water is installed in the receiver tank. When water is mixed into the receiver tank during full water retention and it becomes impossible to maintain full water, the intake valve in the intake pipe is closed and the three-way selector valve in the suction pipe Is used to drain the receiver tank released to the atmosphere.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The full water holding device for a horizontal shaft pump according to the present invention is configured as described above, and when a large amount of rainwater or the like flows into the water intake well, the air in the pump casing of the horizontal shaft pump that is on standby is vacuumed with a high output. The pump is sucked into the receiver tank, and if necessary, a small-output vacuum pump is also started at the same time to raise the water near the shutdown water level of the suction well from the suction pipe of the horizontal axis pump and fill the inside of the pump casing with water. State. Start or continue operation of a low-power vacuum pump to maintain full water. When the water level of the water intake well rises to the pumping start water level, the full water detector checks the pump casing full state, stops the vacuum pump and simultaneously starts the horizontal axis pump to start pumping the water in the water well. Then drain from the drain pipe. When the water level in the water intake well drops to the shutdown water level, the impeller of the horizontal pump is stopped, and one small-power vacuum pump or two small-power vacuum pumps are started immediately, and the pump casing The full water state of the internal water is recovered, and the full water state is maintained until the water level of the water intake well rises to the pumping start water level HWL. Since standby operation is performed with a vacuum pump with a small output, it is energy-saving operation compared to the conventional method.
[0006]
When the fluctuation of the water level is large, the suction pipe circuit to the receiver tank is closed by switching the three-way switching valve of the suction pipe, and the full water state is recovered and held using the negative pressure of the receiver tank. When the water level of the water intake well rises again to the pumping start water level, drainage will be started immediately if the horizontal axis pump is started. When the inflow amount of rainwater or the like into the water intake well fluctuates, the water level fluctuates up and down, so the parallel unused low-output vacuum pumps are operated to cope with resumption of emergency operation of the pumps. If the dry vacuum pump is a Roots pump, the cutoff operation is possible because the friction is small. And even if it is small, high pumping speed can be obtained, no internal lubricating oil is required, and there is no worry of contamination due to backflow of oil to the vacuum side. Further, if ceramic or fluorine resin is coated on the inner surface of the vacuum pump, a rust prevention effect can be obtained, and pump stoppage due to rusting can be avoided.
[0007]
When water is mixed into the receiver tank during full water retention and it becomes impossible to maintain full water, the intake valve of the intake pipe is closed and at the same time the three-way valve is switched to open the receiver tank to the atmosphere without increasing the internal pressure. Open the drain valve and drain the water. Then, the three-way valve is switched to allow the vacuum pump to communicate with the receiver tank, and after the receiver tank has been vacuumed, if the intake valve is opened, the retained water in the pump casing can be held again without falling. After the drainage is completed, the vacuum pump is operated in the atmosphere, and the water accumulated in the vacuum pump is evaporated by operating heat to prevent internal rusting even for a long period until the next operation.
[0008]
【Example】
The present invention will be described in detail with reference to an embodiment. First, in FIG. 1, reference numeral 1 denotes a horizontal shaft pump disposed in a water intake well 2, which is fixed to a horizontal pump casing 3 of the horizontal shaft pump 1 on a main shaft 4. A worn impeller 5 is provided. The suction side of the pump casing 3 is connected to an L-shaped suction casing 6, and the suction casing 6 is connected to a suction pipe 7 submerged in the water well 2. A drain pipe 9 is connected to the discharge side of the pump casing 3 via a discharge valve 8. Reference numeral 10 is a guide vane for rectification provided in the pump casing 3 near the rear of the impeller 5.
[0009]
An intake pipe 11 is connected to an opening 3 a provided in the pump casing 3 above the guide vane 10, and a full water detector 12 for detecting a full water condition inside the pump casing 3 is arranged at the base end of the intake pipe 11. It is set up. The other end of the intake pipe 11 is connected to the receiver tank 13, and an intake valve 14 for shutting off the intake air from the pump casing 3 to the intake pipe 11 and a vacuum breaker valve on the full water detector 12 side that opens the pump casing 3 to the atmosphere. 15 is interposed. A suction pipe 16 is connected to the receiver tank 13, and a three-way switching valve 17 that opens one end to the atmosphere is interposed in the suction pipe 16. Roots pumps 19, 20, and 21 having different capacities in parallel are connected so that the other end of the suction pipe 16 is branched and vacuum suction is performed via a check valve 18. The three-way switching valve 17 interposed in the suction pipe 16 causes the receiver tank 13 to communicate with the roots pumps 19, 20, and 21 to make the receiver tank 13 have a negative pressure, but the three-way switching valve 17 is switched to the receiver tank 13. The circuit of the suction pipe 16 is closed to release the circuit of the Roots pumps 19, 20, and 21 to the atmosphere. In addition, the three-way switching valve 17 is switched to release the circuit of the suction pipe 16 to the receiver tank 13 to the atmosphere, thereby closing the circuits of the roots pumps 19, 20, and 21.
[0010]
Roots pumps 19, 20, and 21 have three-lobe eyebrows-shaped rotors that rotate in the opposite directions at a constant speed in a contactless manner, so that there is little loss of mechanical friction, and continuous cut-off operation for holding full water is possible. Since the friction is small, high-speed rotation is possible, and a high exhaust speed can be obtained even with a small size. No internal lubricating oil is required and there is no concern about contamination due to backflow of oil to the vacuum side. In the embodiment of the present invention, one large output type root pump 19 that sucks and fills the inside of the pump casing and two small output type root pumps 20 and 21 for holding full water are arranged in parallel. . The capacity of the two low-power Roots pumps 20 and 21 is ½ that of the high-power Roots pump 19. When the high-power roots pump 19 fails, backup is performed by operating the two low-power root pumps 20 and 21. When the water is full, one small-output roots pump 20 is operated. When the water-filling time is shortened, the high-power roots pump 19 and one small-output roots pump 20 are operated. A silencer 22 for silencing is provided on the exhaust side of the root pumps 19, 20, and 21, respectively. The inner surfaces of the Roots pumps 19, 20, and 21 are coated with a ceramic coating or a fluorine resin, and an antirust effect is obtained.
[0011]
As shown in FIG. 2, when starting the operation of the horizontal pump, the high-output vacuum pump 19 is operated to set the receiver tank 13 to a negative pressure, and the low-output vacuum pumps 20 and 21 are simultaneously started as necessary. To do. The air inside the pump casing 3 is sucked into the receiver tank 13, the water near the operation stop water level LWL of the suction well 2 is raised from the suction pipe 7 of the horizontal shaft pump 1, and the inside of the pump casing 3 is filled with water. To do. When the water level of the water absorption well 2 is lowered to the operation stop water level LWL and the driving of the impeller 5 of the horizontal shaft pump 1 is stopped, one small output root pump 20 or two low output root pumps. 20 and 21 are activated. The three-way switching valve 17 interposed in the suction pipe 16 causes the root pumps 20 and 21 and the receiver tank 13 to communicate with each other to make the receiver tank 13 have a negative pressure, and sucks air in the pump casing 3 of the horizontal shaft pump 1. The full water state of the shaft pump 1 is recovered and maintained, and the full water state of the pump casing 3 is maintained until the next restart of operation. When the water level of the water intake well 2 fluctuates suddenly, the circuit of the suction pipe 16 from the root pumps 20 and 21 to the receiver tank 13 is closed by switching the three-way switching valve 17 and the negative pressure of the receiver tank 13 is used. It is also possible to recover and maintain the full water condition. One Roots pump 20 may be continuously operated to perform a full water holding operation.
[0012]
A drain valve 23 for draining water is provided at the bottom of the receiver tank 13, and when water is mixed into the receiver tank 13 during holding of the full water and the pump casing 3 cannot hold the full water, the intake valve of the intake pipe 11 14 is closed, the three-way switching valve 17 is switched to open the receiver tank 13 to the atmosphere, and the drain valve 23 is opened to discharge water. After draining the water from the receiver tank 13, the atmosphere of the three-way switching valve 17 is shut off, the suction pipe 16 is connected, the receiver tank 13 is sucked by the small-capacity root pumps 20 and 21, and the intake valve 14 is opened. The full water state of the horizontal shaft pump 1 can be recovered again. When the horizontal axis pump 1 is stopped for a long time, the three-way switching valve 17 is switched to release the root pumps 19, 20, and 21 of the three-way switching valve 17 to the atmosphere, and the root pumps 19, 20, and 21 are operated in the atmosphere. The water accumulated in the Roots pumps 19, 20, and 21 is evaporated by operating heat, and the internal rusting is prevented even if the period until the next rainfall is long.
[0013]
【The invention's effect】
The full-water holding device for a horizontal axis pump according to the present invention is configured as described above, and by providing a dry vacuum pump, a three-way switching valve in a suction pipe, and a drain valve in a receiver tank, it is possible to cope with an emergency. It will be a full water retention device that eliminates the problems of possible horizontal axis pump operation and pump station dehydration. In other words, the water-sealed vacuum pump used in the conventional full water holding device requires the management of a fresh water system at the pump station, which may delay the response in an emergency, and has a problem of rusting of equipment. In addition, there is a possibility that water may be mixed into the receiver tank and the pump cannot be fully filled. In the present invention, an opening is provided in the upper part of the pump casing of the horizontal shaft pump. In a horizontal axis pump in which a full water detector and an intake valve are arranged at the end of the intake pipe connected to the intake pipe, the intake pipe is connected to a vacuum pump via a receiver tank, and the horizontal axis pump at start-up is filled with water The suction pipe connected to the receiver tank is equipped with a three-way switching valve for switching communication with the atmosphere, and the other end of the suction pipe is branched and connected to a dry vacuum pump having a different capacity. Operate and suck the receiver tank with a small output vacuum pump while the horizontal axis pump is on standby, or close the suction pipe with a three-way selector valve and use the negative pressure of the receiver tank to Full water condition It is those that can be recovered and held.
[0014]
If the dry vacuum pump is a Roots pump, it is possible to perform a cut-off operation because the friction is small, a high pumping speed is obtained, no internal lubricating oil is required, and there is no fear of contamination due to the backflow of oil to the vacuum side. After the drainage is completed, if the three-way switching valve is switched to release the roots pump to the atmosphere, the water accumulated in the roots pump can be evaporated by the operation heat to prevent rusting inside. If the inner surface of the vacuum pump is rust-proofed with ceramic coating or fluorine resin coating, a rust-proofing effect can be obtained. In addition, a drain valve for draining water is provided in the receiver tank, so that when the water enters the receiver tank while it is full, the receiver tank can be drained by closing the intake valve and releasing the receiver tank to the atmosphere. Can do. If the receiver tank is drained while the Roots pump is closed, and the intake valve is opened after the receiver tank has been vacuumed, the horizontal pump can quickly recover full water retention.
[Brief description of the drawings]
FIG. 1 is a flowchart of a full water holding device for a horizontal axis pump according to the present invention.
FIG. 2 is a longitudinal sectional view of a horizontal axis pump that shows a full water state in the same manner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Horizontal shaft pump 3 Pump casing 3a Opening part 11 Intake pipe 12 Full detector 13 Receiver tank 14 Intake valve 16 Suction pipe 17 Three-way selector valve 19, 20, 21 Roots pump 23 Drain valve

Claims (4)

An opening (3a) is provided in the upper part of the pump casing (3) of the horizontal shaft pump (1), and a full water detector (12) and an intake air are provided at the proximal end of the intake pipe (11) connected to the opening (3a). A valve (14) is provided, and the intake pipe (11) is connected to the vacuum pump (19, 20, 21) via the receiver tank (13), so that the horizontal axis pump (1) at the start is in a full state. In the horizontal axis pump, a suction pipe (16) connected to the receiver tank (13) is provided with a three-way switching valve (17) for switching communication with the atmosphere, and the other end of the suction pipe (16) is branched. Connected to dry vacuum pumps (19, 20, 21) with different capacities and sucks receiver tank (13) with low output vacuum pumps (20, 21) during standby of horizontal axis pump (1), or The suction pipe (16) is closed with the three-way switching valve (17), Sieber tank (13) of the full capacity retention device on the horizontal axis pump, characterized in that to recover and hold a horizontal axis pump (1) to the full level by utilizing a negative pressure. The full-water holding device for a horizontal shaft pump according to claim 1, wherein the dry vacuum pumps (19, 20, 21) are Roots pumps having different capacities. 3. A full-water holding device for a horizontal shaft pump according to claim 1, wherein the inner surface of said vacuum pump (19, 20, 21) is subjected to a rust prevention process of ceramic coating or fluorine resin coating. The receiver tank (13) is provided with a drain valve (23) for draining, the intake valve (14) of the intake pipe (11) is closed, and the three-way switching valve (17) of the suction pipe (16) is switched to 4. The full-water holding device for a horizontal pump according to any one of claims 1 to 3, wherein the receiver tank (13) that has been released is drained.

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