JP5063744B2 - Vertical shaft pump - Google Patents

Description

  The present invention relates to a vertical shaft pump.

  The vertical shaft pump described in Patent Document 1 includes a return pipe extending from the upstream side of the gate valve to the bottom of the suction water tank, and a nozzle pipe piped on the bottom of the suction water tank and connected to the return pipe. . During the management operation, the gate valve is closed, and the discharge water of the vertical shaft pump is pumped from the return pipe to the nozzle pipe, and is ejected from the nozzle provided in the nozzle pipe into the suction water tank. The water ejected from the nozzle has accumulated at the bottom of the suction water tank and floats foreign matter such as residue and sand in the water. When normal operation of the vertical pump is performed in this state, foreign matter is sucked into the vertical pump together with water and is pumped downstream. That is, the suction water tank is cleaned using the water returned to the suction water tank to prevent overheating during the management operation.

  In the vertical shaft pump described in Patent Document 1, it is necessary to connect a nozzle pipe to the bottom of the suction water tank separately from the casing and the like, and it is necessary to connect a return pipe to the nozzle pipe separately from the casing. The structure is complicated and the installation work is complicated.

  Moreover, in the vertical shaft pump described in Patent Document 1, it is necessary to provide a vortex generation prevention device such as a prevention plate for preventing the generation of vortices in the suction water tank separately from the return pipe line and the nozzle pipe. In this respect, the structure is complicated.

JP 2006-200502 A

  An object of the present invention is to provide a vertical shaft pump that can effectively clean a suction water tank during a management operation, while having a simple configuration and easy installation work.

The present invention has a suction port that extends in the vertical direction and opens at the lower end side so as to face the bottom of the suction water tank, is connected to a discharge pipe having a gate valve on the upper end side, and has an impeller on the lower end side. A casing in which a fixed main shaft is disposed, and a branch from an upstream side of the upper end side of the gate valve to the upper end side of the casing, extends in a vertical direction along the casing toward the bottom of the suction water tank, and is normally closed A plurality of nozzles connected to the lower end side of the vertical pipe so as to surround the outside of the casing with a space therebetween, and facing the bottom of the suction water tank And a first annular pipe that is outward in the plan view, a sensor for detecting the closing of the gate valve, and when the valve closing of the gate valve is detected by an input from the sensor, Control device that opens the on-off valve Comprising the door, it provides a vertical shaft pump.

  The gate valve is closed during the management operation. The control device that detects the opening of the gate valve by the input from the sensor opens the on-off valve. As a result, the water sucked into the casing from the suction water tank through the suction port is pumped from the vertical pipe to the annular pipe and returned to the suction water tank by being ejected from the nozzle. Such a circulating flow of water through the casing prevents overheating of the vertical pump during the management operation.

  Since the nozzle of the annular pipe faces the bottom of the suction water tank, foreign matter such as sediment and sand deposited on the bottom of the suction water tank is blown up by the water flow ejected from the nozzle during management operation, and the water in the suction water tank To float. The water ejected from the nozzle of the annular pipe collides with the bottom of the suction water tank or foreign matter accumulated on it, so that a complicated water flow is generated near the bottom of the suction water tank, and the foreign matter accumulated at the bottom is more effective. Can be suspended. The normal operation of the vertical shaft pump is performed after the foreign matter is sufficiently floated, and the inside of the suction water tank can be effectively cleaned by sucking the foreign matter together with water into the vertical pump and pumping it downstream.

  There is no need to provide piping at the bottom of the suction water tank separately from the casing, and there is no need to provide a pipe for connecting the piping at the bottom of such a suction water tank to the upper end side (discharge pipe line) side of the casing. The structure is simple. Further, when the casing is installed in the suction water tank, the vertical pipe connected to the casing and the annular pipe connected to the vertical pipe are both installed in the suction water tank. In this respect, the installation work is simple.

  Moreover, the vertical pipe extending in the vertical direction along the casing can prevent the vortex in the suction water tank around the suction port from being generated during normal operation. That is, the vertical pipe also serves as a vortex generation prevention device, and it is not necessary to provide a separate vortex generation prevention device. Also in this respect, the structure is simple.

If the sensor is a pressure sensor that is placed on the upstream side of the gate valve, wherein the control device, exceeds the pressure detection pressure of the pressure sensor is predetermined, the partition valve is closed and to decide.

If the sensor is a flow rate sensor disposed on the downstream side of the gate valve, the control device determines that the gate valve is closed when the detected flow rate of the flow sensor falls below a predetermined flow rate. To do.

The apparatus may further include a second annular pipe disposed on the lower side with a vertical interval with respect to the first annular pipe, and the nozzle of the second annular pipe may be inward in a plan view. .

Specifically, the vertical shaft pump is provided with a discharge bend on the upper end side of the casing, and a horizontal pipe extending in the horizontal direction with one end connected to the discharge bend and provided with a viewing window on the other end. The upper end side of the pipe branches off from the horizontal pipe.

According to this configuration, since the vertical pipe can be connected via the horizontal pipe to the portion where the existing discharge bend viewing window is provided, the present invention can be implemented with a relatively simple modification of the existing vertical shaft pump.

  The vertical shaft pump of the present invention can clean the suction water tank effectively during the management operation while being simple and easy to install in the suction water tank.

Sectional drawing of the vertical shaft pump which concerns on 1st Embodiment of this invention. Sectional drawing in the II-II line of FIG. The fragmentary sectional view which shows the alternative of arrangement | positioning of annular piping. The fragmentary sectional view of the vertical shaft pump which concerns on 2nd Embodiment of this invention. Sectional drawing in the VV line | wire of FIG. The graph which shows a HQ diagram etc.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
A vertical shaft pump 1 according to the first embodiment of the present invention shown in FIG. 1 includes a straight tubular casing 2 extending in a substantially vertical direction. The casing 2 is being fixed in the state inserted in the opening part 3a with respect to the floor structure 3 of a pump station. The suction port 4a provided in the suction bell mouth 4 on the lower end side of the casing 2 is opposed to the bottom 5a of the suction water tank 5 with a distance of about 1.3 times the diameter of the suction port 4a, for example. A gate 8 (normally closed and can be manually opened and closed in this embodiment) is provided at the discharge port 7a provided in the discharge bend 7 (curved 90 degrees toward the front side in FIG. 1) on the upper end side of the casing 2. An intervening discharge pipe 9 is connected. The main shaft 11 with the impeller 10 fixed to the lower end side is disposed in the casing 2 so as to extend in the vertical direction, and is rotatably supported by bearings 13A, 13B, and 13C. The upper end of the main shaft 11 protruding from the discharge bend 7 to the outside of the casing 2 is connected to a drive mechanism 14 including a motor, a speed reducer, and the like.

The suction bell mouth 4 in the present embodiment has a double structure including an upper suction bell 15 and a lower suction bell 16 disposed below the upper suction bell 15. 6 (the horizontal axis at a rate _{Q / Q opt} of the flow rate Q with respect to the optimum flow rate _{Q opt,} the vertical axis represents the ratio _{H / H opt} of lift H to the optimum lifting height _{H opt)} Referring also to rated operation range (e.g., Q / Q _opt is in the range of about 0.6 to 1.2), water is sucked up from the lower end opening 16a of the lower suction bell 16, but from the flow path 17 between the upper suction bell 15 and the lower suction bell 16. There is no inflow of water. Next, in an excessive flow rate region (for example, Q / Q _{opt of} about 1.2 or more), water is sucked into the casing 2 from both the lower end opening 16 a and the flow path 17. In the partial flow rate region (for example, Q / Q _opt is less than about 0.6), a part of the water sucked up from the lower end opening 16a of the lower suction bell 16 is jetted from the flow path 17 to the suction water tank 5 as the backflow water. This double-structured suction bell mouth 4 itself is known, and details of its structure and function are described in Japanese Patent Application Laid-Open No. 2004-176567. However, the present invention can also be applied to a vertical pump in which a bell mouth has a normal single structure. In FIG. 6, η is efficiency and L is shaft power.

T-shaped pipe 19A to a position symmetrical in Figure 1 of the discharge bend 7, one end of the 19B (horizontal pipes) are connected. Viewing windows 20A and 20B are provided at the other ends of the portions extending in the horizontal direction of the T-shaped tubes 19A and 19B. In addition, there is a portion branched downward in the vertical direction from the middle of the portion of the T-shaped tubes 19A, 19B extending in the horizontal direction, and one end of the straight tubular vertical pipes 21A, 21B is connected to this portion. These two vertical pipes 21A and 21B are provided with on-off valves 22A and 22B (normally closed electric butterfly valves in this embodiment) in the vicinity of the T-shaped pipes 19A and 19B. The vertical pipes 21 </ b> A and 21 </ b> B are arranged on the outside of the casing 2 with a space therebetween and extend downward in the vertical direction in parallel with the main shaft 11. Specifically, in the present embodiment, the vertical pipes 21A and 21B extend from the T-shaped pipes 19A and 19B through the opening 3a to a position slightly above the impeller 10. The vertical pipes 21 </ b> A and 21 </ b> B may be connected to the casing 2 or the suction water tank 5 at one place or a plurality of places.

  An annular pipe 23 is connected to the lower ends of the vertical pipes 21A and 21B. The annular pipe 23 in the present embodiment is an annular shape centering on the axis 11 a of the main shaft 11, and is disposed so as to surround the outside of the casing 2 with a space therebetween. One or more annular pipes 23 may be connected to the casing 2 or the suction water tank 5. For example, the annular pipe 23 may be connected to the lower surface side of the floor structure 3 by a plurality of rods 25 (only shown in FIG. 2) extending in the vertical direction. Referring also to FIG. 2, a plurality (eight in this embodiment) of nozzles 26 are provided in the annular pipe 23 at equal angular intervals around the axis 11 a of the main shaft 11 in plan view. All eight nozzles 26 face downward and face the bottom 5 a of the suction water tank 5. The depression angle θ1 of the nozzle 26 is set to about 30 degrees, for example. Referring to FIG. 2, in this embodiment, the direction of the nozzle 26 in plan view is the radial direction of the main shaft 11 and outward (the water flow is ejected away from the main shaft 11).

  The depression angle θ1 may be different among the individual nozzles 26. Further, the orientation of the nozzle 26 in a plan view may be inclined to the rotation direction (reference R) side of the main shaft 11 as shown by reference numeral β1 in FIG. 2, and conversely, the main shaft 11 as shown by reference numeral β1. You may incline to the opposite side to the rotation direction. Further, as in the alternative shown in FIG. 3, the lower ends of the vertical pipes 21A and 21B are located below the suction port 4a of the suction bell mouth 4, and the annular pipe 23 connected to the lower ends of the vertical pipes 21A and 21B is a suction bell. It may be located below the mouse 4. These points are the same in the second embodiment described later.

  A pressure sensor 27 is disposed upstream of the gate valve 8 of the discharge pipe 9. The control device 28 detects that the gate valve 8 has been opened based on the input from the pressure sensor 27, and opens the on-off valves 22 </ b> A and 22 </ b> B when detecting the valve opening of the gate valve 8. Specifically, a sufficiently high pressure is preset as the threshold pressure Pth, and the control device 28 determines that the gate valve 8 is closed when the detected pressure of the pressure sensor 27 exceeds the threshold pressure Pth.

The pressure sensor 27 may be disposed upstream of the gate valve 8, and may be disposed in the discharge bend 7, for example. In addition, as shown by a broken line in FIG. 1, a flow rate sensor 29 is disposed upstream of the gate valve 8 of the discharge pipe 9 instead of the pressure sensor 27, and the control device 28 is based on the input from the flow rate sensor 29. The opening of the gate valve 8 may be detected. In this case, a sufficiently small flow rate is preset as the threshold flow rate qth, and the control device 28 determines that the gate valve 8 is closed when the flow rate detected by the flow rate sensor 29 falls below the threshold flow rate qth.

  Next, operation | movement of the vertical shaft pump 1 of this embodiment is demonstrated.

When the normal operation is not performed over a long period of time, the vertical shaft pump may be operated for the purpose of maintaining performance, not for draining the water in the suction water tank 5 (management operation). At the time of management operation, in the case of this embodiment, the vertical shaft pump 1 is started after the gate valve 8 is manually closed by the operator of the pump station. When the vertical shaft pump 1 is activated, the pumping of water in the suction water tank 5 sucked into the casing is shut off by the gate valve 8, so that the pressure detected by the pressure sensor 27 increases. When the detected pressure of the pressure sensor 27 exceeds the threshold pressure Pth, the control device 28 opens and closes the on-off valves 22A and 22B. When the on-off valves 22A and 22B are opened, the water in the suction water tank 5 sucked from the suction port 4a of the suction bell mouth 4 from the casing 2 (discharge bend 7) as shown by an arrow A1 in FIG. It is pumped to the annular pipe 23 via 19A, 19B and the vertical pipes 21A, 21B. Specifically, in FIG. 6, the flow rate ratio and the head ratio at the time of management operation are Qb and Hb, respectively, which are partial flow rate regions. Therefore, most of the water sucked up from the lower end opening 16a of the lower suction bell 16 as shown by an arrow A1 in FIG. 1 is pumped to the annular pipe 23, but a part of the upper suction is shown as an arrow A2. From the flow path 17 between the bell 15 and the lower suction bell 16, it is ejected (reverse flow) into the suction water tank 5.

  The water pumped to the annular pipe 23 is ejected from the nozzle 26 into the suction water tank 5 as shown by an arrow A3 in FIGS. That is, during the management operation, the water sucked into the casing 2 from the suction water tank 5 returns to the suction water tank 5 through the T-shaped pipes 19A and 19B, the vertical pipes 21A and 21B, the annular pipe 23, and the nozzle 26. Such a circulating flow of water through the casing 2 prevents overheating of the vertical pump 1 during management operation (for example, excessive temperature rise due to frictional heat generated in the bearings 13A to 13C).

  Since the nozzle 26 of the annular pipe 23 faces the bottom portion 5a of the suction water tank 5, foreign matters such as residue and sand deposited on the bottom portion 5a of the suction water tank 5 are ejected from the nozzle 26 during the management operation (arrows). It is blown up by A2) and floats in the water in the suction tank 5. Since the water ejected from the nozzle 26 of the annular pipe 23 collides with the bottom 5a of the suction water tank 5 or foreign matter deposited on the bottom 5a, a complex water flow is generated near the bottom 5a of the suction water tank 5, and is deposited on the bottom 5a. The foreign matter that has been stored can be suspended more effectively. Since the head ratio Hb (partial flow rate range) during the management operation is generally higher than that during normal operation, which is a rated operation range or an excessive flow rate range, the pressure of water ejected from the nozzle 26 can be secured.

  As described above, during the management operation, water is also ejected from the flow path 17 between the upper suction bell 15 and the lower suction bell 16 (arrow A2), and the water ejected from the flow path 17 also enters the bottom 5a of the suction water tank 5. This has the effect of blowing up the accumulated foreign matter. That is, in this embodiment, the foreign matter is suspended by two types of water flows (arrows A2 and A3) toward the bottom of the suction water tank 5. However, even if the suction bell mouth 4 has a normal single structure, the foreign matter deposited on the bottom 5a can be effectively suspended only by water (arrow A3) ejected from the nozzle 26.

  If normal operation of the vertical pump 1 is performed after the foreign matter is sufficiently floated, the inside of the suction water tank 5 can be effectively cleaned by sucking the foreign matter into the vertical pump 1 together with water and pumping it downstream.

  In the vertical shaft pump 1 of the present embodiment, it is necessary to provide piping at the bottom 5a of the suction water tank 5 separately from the casing 2, and the piping at the bottom of the suction water tank 5 is connected to the upper end side (discharge pipe 9) side of the casing 2. There is no need to provide a pipe line for connection separately from the casing 2, and the structure is simple. Further, when the casing 2 is installed in the suction water tank 5, if it is fixed to the casing 2 of the floor structure 3 inserted into the opening 3a from above, the vertical pipes 21A and 21B and the vertical pipes 21A and 21B connected to the casing 2 are used. An annular pipe 23 connected to the suction water tank 5 can be installed together with the casing 2. In this respect, the vertical shaft pump 1 of the present embodiment is easy to install in the suction water tank 5.

  The vertical pipes 21A and 21B extending in the vertical direction along the casing 2 can prevent the vortex from being generated in the suction water tank 5 around the suction port during normal operation. That is, the vertical pipes 21A and 21B also serve as a vortex generation prevention device, and it is not necessary to provide a separate vortex generation prevention device. Also in this respect, the vertical shaft pump 1 of this embodiment has a simple structure.

The T-shaped pipes 19A and 19B for connecting the upper ends of the vertical pipes 21A and 21B to the discharge bend 7 are obtained by performing a comparatively simple modification on the existing existing vertical pump, whereby the vertical pump 1 of the present embodiment. Can be made.

(Second Embodiment)
In the vertical pump 1 according to the second embodiment of the present invention shown in FIGS. 4 and 5, the same annular pipe 23 as that of the first embodiment is connected above the lowermost ends of the vertical pipes 21 </ b> A and 21 </ b> B. On the other hand, another annular pipe 23 ′ is connected to the lowermost ends of the vertical pipes 21 </ b> A and 21 </ b> B at intervals in the vertical direction. As in the first embodiment, the nozzle 26 of the upper annular pipe 23 is outward in plan view. On the other hand, the plurality of (eight in the present embodiment) nozzles 26 ′ arranged at equal angular intervals in plan view on the lower annular pipe 23 ′ are directed downward (the depression angle θ 2 is about 30 degrees, for example). However, the orientation in a plan view is inward in the radial direction of the main shaft 11 (a water flow is ejected in a direction approaching the main shaft 11).

  In the case of this embodiment, three types of downward water flows, that is, water flows (arrows A3 and A4) ejected from the nozzles 26 and 23 ′ of the upper and lower annular pipes 23 and 23 ′, and the flow path 17 of the suction bell mouth 4 are shown. The water flow (arrow A2) that flows backward from the water is sprayed to the bottom 5a of the suction water tank 5. Further, the water flows (arrows A3 and A4) ejected from the nozzles 26 and 26 'of the upper and lower annular pipes 23 and 23' have different directions (inward or outward) in plan view. In these respects, the bottom 5a of the suction water tank 5 can be effectively cleaned by floating the foreign matter deposited more effectively and performing normal operation.

DESCRIPTION OF SYMBOLS 1 Vertical shaft pump 2 Casing 3 Floor structure 3a Opening part 4 Suction bellmouth 4a Suction port 5 Suction water tank 5a Bottom part 7 Discharge bend 7a Discharge port 8 Gate valve 9 Discharge pipe 10 Impeller 11 Main shaft 11a Axis 13A, 13B, 13C Bearing 14 Mechanism 15 Upper suction bell 16 Lower suction bell 16a Lower end opening 17 Flow path 19A, 19B T-shaped tube 20A, 20B Viewing window 21A, 21B Vertical piping 22A, 22B On-off valve 23, 23 'Annular piping 25 Rod 26, 26' Nozzle 27 Pressure sensor 28 Control device 29 Flow sensor

Claims (5)

A spindle that extends in the vertical direction, has a suction port that opens at the lower end side to face the bottom of the suction water tank, is connected to a discharge pipe with a gate valve on the upper end side, and has a main shaft that fixes the impeller to the lower end side. A casing which is arranged,
At least one branching from the upstream side than the gate valve on the upper end side of the casing, extending vertically along the casing toward the bottom portion of the suction water tank, and having a normally closed on-off valve interposed Vertical piping,
A first pipe connected to the lower end side of the vertical pipe so as to surround the outside of the casing with a gap , and having a plurality of nozzles facing the bottom of the suction water tank , and facing outward in the plan view; Annular piping,
A sensor for detecting the closing of the gate valve;
A vertical shaft pump comprising: a control device that opens the on-off valve when the closing of the gate valve is detected by an input from the sensor. It said sensor is a pressure sensor that is placed on the upstream side of the gate valve,
The vertical shaft pump according to claim 1, wherein the control device determines that the gate valve is closed when a detected pressure of the pressure sensor exceeds a predetermined pressure. The sensor is a flow rate sensor disposed downstream of the gate valve;
The vertical shaft pump according to claim 1, wherein the control device determines that the gate valve is closed when a detected flow rate of the flow rate sensor falls below a predetermined flow rate . The apparatus further comprises a second annular pipe arranged on the lower side with a vertical interval with respect to the first annular pipe, and the nozzle of the second annular pipe is inward in a plan view. The vertical shaft pump according to any one of claims 1 to 3. A discharge bend on the upper end side of the casing;
A horizontal pipe extending in the horizontal direction with one end connected to the discharge bend and provided with a viewing window on the other end;
The vertical shaft pump according to any one of claims 1 to 4 , wherein an upper end side of the vertical pipe is branched from the horizontal pipe.

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