JP2013122238A - Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a suction water tank to be efficiently cleaned during maintenance operation and efficiently prevent generation of air suction vortex while having a simple structure facilitating installation work.SOLUTION: A pump is provided with a water tank cleaning device 16 including a vertical pipe 18, an annular pipe 20, an on-off valve 19, and many connection ribs 22. The vertical pipe 18 is branched from an upstream side from a gate valve 7 at an upper end side of a casing 3 and extends in the vertical direction along the casing 3 toward a bottom part 5a of a suction water tank 5 so as to be positioned at a downstream side in an inflow direction of a suction bell mouth 4 into the suction water tank 5, when viewing the suction bell mouth 4 from an axial direction upper side. The annular pipe 20 is connected at the lower end side the vertical pipe 18 outside the suction bell mouth 4 at a clearance to surround it, and includes a plurality of nozzles 21 directed to the bottom part 5a of the suction water tank 5. The on-off valve causes cleaning treatment for injecting water in the casing 3 into the suction water tank 5 through the vertical pipe and the annular pipe to be executed or stopped. The many connection ribs are provided between the suction bell mouth 4 and the annular pipe 20.

Description

  The present invention relates to a pump for draining water stored in a suction water tank.

  Patent Document 1 discloses a water tank cleaning device including a return pipe extending from the upstream side of the gate valve to the bottom of the suction water tank, and a nozzle pipe connected to the return pipe and piped on the bottom of the suction water tank. The installed vertical shaft pump is described. When this vertical shaft pump is operated with the gate valve closed during the management operation, the discharge water is pumped from the return pipe to the nozzle pipe, and is ejected from the nozzle of the nozzle pipe into the suction water tank. As a result, foreign matter such as sediment and sand that has accumulated at the bottom of the suction tank is suspended in the water, and then the vertical shaft pump is operated normally, so that the foreign matter is pumped downstream together with the water, and the suction tank is cleaned. It is carried out.

  However, the vertical shaft pump of Patent Document 1 needs to connect a nozzle pipe to the bottom of the suction water tank separately from the casing, and also needs to connect a return pipe to the nozzle pipe separately from the casing. The structure is complicated and the installation work is complicated. In addition, in this type of vertical shaft pump, it is known that during normal operation, air is sucked into the suction port from the water surface around the suction port due to lowering of the water level in the suction water tank, etc., and a vortex (air suction vortex) is generated. . This air suction vortex prevents smooth suction of water into the suction port and causes vibration and noise. Therefore, since it is necessary to further provide a means for preventing the generation of the air suction vortex, the structure is complicated also in this respect.

  On the other hand, Patent Literature 2 describes a vertical shaft pump that can suppress the generation of air suction vortices. In this vertical shaft pump, a sub-flow channel forming plate having a disk shape or a cylindrical shape is disposed on the outer peripheral portion of the suction bell mouth at the lower end of the casing, and a sub flow channel through which water flows is formed therebetween. . As a result, the water flow toward the suction port of the suction bell mouth is divided into a main flow that flows outside the sub-flow channel forming plate and a sub-flow that flows through the sub-flow channel, and the two are collided near the lower end of the suction bell mouth. The air suction vortex is eliminated.

  However, although the vertical pump of Patent Document 2 can suppress the generation of the air suction vortex, there is still room for improvement. In addition, in the vertical shaft pump of Patent Document 2, it is necessary to provide a means for cleaning the inside of the suction water tank during the management operation, so that the structure becomes complicated.

JP 2006-200502 A Japanese Patent No. 4117699

  It is an object of the present invention to provide a pump capable of effectively cleaning the suction water tank during management operation and effectively suppressing the generation of air suction vortices while having a simple and easy installation operation. It is.

  In order to solve the above-mentioned problem, the pump of the present invention is a discharge pipe in which a suction bell mouth having a suction port opened at the lower end side facing the bottom of the suction water tank is disposed, and a gate valve is provided on the upper end side. Is connected, and the main shaft with the impeller fixed to the inner end side through which it is connected is branched from the upstream side of the gate valve on the upper end side of the casing, and the suction bell mouth is axially A vertical pipe extending in the vertical direction along the casing toward the bottom of the suction water tank so as to be located on the downstream side in the direction of water inflow into the suction water tank of the suction bell mouth as seen from above. An annular pipe having a plurality of nozzles connected to the lower end side of the vertical pipe so as to surround the suction bell mouth with a space therebetween and facing the bottom of the suction water tank, the vertical pipe and the annular arrangement And an open / close valve for executing or stopping a cleaning process for ejecting water in the casing into the suction water tank, and connecting the casing and the water tank cleaning apparatus with a plurality of connecting ribs. The configuration is as follows.

  This pump is operated with the gate valve closed and the on-off valve opened during the management operation. Thereby, 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 pump during the management operation. Further, since the nozzle of the annular pipe faces the bottom of the suction water tank, foreign matters such as residue and sand are deposited on the bottom of the suction water tank due to the water flow ejected from the nozzle. As a result, the inside of the suction water tank can be effectively cleaned by continuing normal operation of the pump and sucking foreign matter together with water from the suction port and pumping it downstream.

  On the other hand, when the water in the suction water tank is drained to the vicinity of the impeller by the normal operation, an air suction vortex is generated in a region downstream of the suction bell mouth in the inflow direction into the suction water tank. However, in this invention, since the vertical piping of the water tank cleaning device is piped so that it may be located in the inflow direction downstream in the suction water tank, generation | occurrence | production of the air suction vortex on the water surface can be suppressed. Moreover, since the annular pipe of the water tank cleaning device is arranged on the outer periphery of the suction bell mouth, the water flow toward the suction port is divided into a main flow that flows outside the annular pipe and a side flow between the annular pipe and the suction bell mouth. It can be extinguished by diverting it into a side stream flowing through the road and causing these to collide with the lower end of the suction bell mouth. Therefore, generation | occurrence | production of an air suction vortex can be prevented reliably.

  Thus, in this invention, since it is not necessary to arrange | position a water tank cleaning apparatus in a suction water tank separately from a casing, a structure is simple. Moreover, when installing a casing in a suction water tank, the water tank cleaning apparatus connected with the casing by the connection rib is also installed in a suction water tank. Therefore, the installation work is simple. Moreover, since this water tank cleaning device also serves as a vortex generation prevention device that prevents the generation of air suction vortices, it is not necessary to provide a separate vortex generation prevention device. Also in this respect, the structure is simple.

  In this pump, it is preferable that the connecting rib is provided between the suction bell mouth and the annular pipe. In this way, the connecting rib can be made to function as a rectifying plate that prevents the swirling flow generated at the outer peripheral portion of the suction bell mouth, so that the generation of the air suction vortex can be prevented more reliably.

Further, in the suction bell mouth, three or more underwater vortex preventing ribs projecting downward from the suction mouth of the suction bell mouth and extending radially outward from the axis are disposed, and the outside of the underwater vortex preventing ribs It is preferable to incline the edge outward and to arrange the annular pipe on the extension line. If it does in this way, the underwater vortex prevention rib can suppress the underwater vortex which generate | occur | produces not in the water surface but in water. And since the subflow path which can form a subflow effectively between annular piping and a suction bell mouth can be formed, generation | occurrence | production of an air suction vortex can be suppressed reliably.
In this case, it is preferable that the outer edge of the underwater vortex preventing rib is composed of a curved edge protruding radially outward from the lower end edge of the suction bell mouth. In this way, the pump can be laid down horizontally from the standing state or erected from the horizontal state with the underwater vortex preventing rib as a fulcrum. Therefore, installation workability to the pump station and workability during disassembly can be improved.

Moreover, it is preferable that the said vertical piping is arrange | positioned on the basis of the reference line which connects the axial line of the said suction bellmouth, and the inflow direction downstream corner | angular part of the said suction water tank. In this way, generation | occurrence | production of an air suction vortex can be reliably suppressed by vertical piping.
The nozzle is preferably outward in plan view. If it does in this way, the foreign material deposited in the suction water tank can be blown up reliably, and it can discharge with water.

The casing is a vertical shaft pump including an impeller case for disposing the impeller above the suction bell mouth, and the main shaft extending in a vertical direction.
In this case, the annular pipe is preferably disposed so as to be positioned between the impeller and the suction port of the suction bell mouth. In this way, a sub-flow path capable of forming a sub-flow can be formed between the annular pipe and the suction bell mouth, so that the generation of air suction vortices can be reliably suppressed.
Alternatively, the casing is a horizontal shaft pump including an impeller case for disposing the impeller on the upstream side of the discharge pipe, and the main shaft extending in the lateral direction.

  While the pump of the present invention is simple and easy to install, the suction water tank can be effectively cleaned during management operation, and the generation of air suction vortices can be effectively suppressed.

1 is a side sectional view showing a vertical shaft pump according to a first embodiment of the present invention. The rear view which shows the state which looked at the vertical shaft pump of FIG. 1 from the back surface It is a principal part top view of a vertical shaft pump. It is a principal part expanded sectional view of FIG. It is a principal part expanded sectional view which shows the vertical shaft pump of 2nd Embodiment. It is a principal part expanded sectional view which shows the vertical shaft pump of 3rd Embodiment. It is sectional drawing which shows the installation and disassembly work process of the vertical shaft pump of 3rd Embodiment. It is sectional drawing which shows the horizontal axis pump which is 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show a vertical shaft pump 1 that is a drainage pump according to a first embodiment of the present invention. This vertical shaft pump 1 is provided with a straight tubular casing 3 that is fixed in a state of being inserted into an opening 2a with respect to a floor 2 of a pump station, and extends in a substantially vertical direction. And the vertical shaft pump 1 of this invention integrally attaches to this casing 3 with the water tank cleaning apparatus 16 which also serves as a vortex generation prevention apparatus.

  On the lower end side of the pumping pipe 3a of the casing 3, a suction bell mouth 4 that is gradually expanded downward so that the outer shape forms an arc shape is disposed. The suction port 4a formed by the lower end opening of the suction bell mouth 4 is disposed to face 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. Further, on the upper end side of the casing 3, a discharge bend 6 curved by 90 degrees is disposed so as to change the flow of water from the vertical direction to the horizontal direction. A discharge pipe 8 provided with a manually opened / closed gate valve 7 is connected to the discharge port 6 a of the discharge bend 6.

  In the casing 3, a main shaft 9 is disposed so as to extend in the vertical direction along the axis, and the main shaft 9 is rotatably supported by bearings 10A, 10B, and 10C. An impeller 11 is fixed to the lower end side of the main shaft 9. The impeller 11 is disposed by a bearing 10 </ b> C in an impeller case 12 disposed so as to be positioned on the suction bell mouth 4. An upper end of the main shaft 9 protruding from the discharge bend 6 to the outside of the casing 3 is connected to a drive mechanism 13 including a motor, a speed reducer, and the like.

  The suction bell mouth 4 of the present embodiment is provided with an axial bell mouth 14 integrally formed with an underwater vortex prevention rib 15. This axial center bell mouth 14 is made of resin such as FRP, and is a substantially conical cylindrical axial center portion arranged so as to extend along the axis of the suction bell mouth 4. The lower end opening 14 a of the axial bell mouth 14 is positioned below the suction port 4 a of the suction bell mouth 4 and is positioned above the bottom portion 5 a of the suction water tank 5 with a predetermined interval. Further, the lower end opening 14 a of the axial bell mouth 14 is formed to have a smaller diameter than the diameter of the suction port 4 a of the suction bell mouth 4.

  The underwater vortex preventing rib 15 serves as a current plate that can effectively eliminate the underwater vortex. The underwater vortex preventing rib 15 of the present embodiment is provided on the outer surface of the axial bell mouth 14 and also serves to connect the axial bell mouth 14 to the suction bell mouth 4. The underwater vortex preventing ribs 15 are provided at four equal intervals in the circumferential direction so as to protrude radially outward from the axis of the suction bell mouth 4. The upper end surface of the underwater vortex prevention rib 15 is formed in an arc shape along the inner surface of the suction bell mouth 4 and is connected by a bolt or the like (not shown). Further, the underwater vortex preventing rib 15 protrudes from the outer peripheral portion of the lower end of the axial bell mouth 14. Thereby, each underwater vortex preventing rib 15 is provided so as to protrude downward from the suction port 4 a of the suction bell mouth 4. Further, the outer edge 15a of the underwater vortex preventing rib 15 is configured to extend obliquely upward at a predetermined angle.

  The water tank cleaning device 16 is for cleaning the suction water tank 5 for the purpose of maintaining drainage performance. The water tank cleaning device 16 includes four vertical pipes 18A1 to 18B2 connected to the discharge bend 6 and an annular pipe 20 connected to the lower ends thereof, and is connected to the casing 3 by a connecting rib 22. Yes.

  In the casing 3, horizontal pipes 17 </ b> A and 17 </ b> B are branched and connected to symmetrical positions of the discharge bend 6 located on the upstream side of the gate valve 7. As shown in FIG. 2, these horizontal pipes 17A and 17B are composed of a connecting pipe part 17a connected to the discharge vent 6 and a branch pipe extending in parallel to the floor 2 and branchingly connected in an orthogonal direction to the connecting pipe part 17a. Part 17b. A pair of vertical pipes 18A1 and 18A2 are branched and connected to the branch pipe part 17b of the horizontal pipe 17A, and a pair of vertical pipes 18B1 and 18B2 are branch-connected to the branch pipe part 17b of the horizontal pipe 17B.

  The vertical pipes 18 </ b> A <b> 1 to 18 </ b> B <b> 2 are arranged at intervals on the radially outer side of the casing 3, and extend downward in the vertical direction in parallel with the main shaft 9. As shown in FIG. 3, when the suction bell mouth 4 of the casing 3 is viewed from the upper side in the axial direction, the vertical pipes 18 </ b> A <b> 1 and 18 </ b> B <b> 1 are located on the upstream side in the water inflow direction from the main shaft 9 into the suction water tank 5. Has been. The vertical pipes 18A2 and 18B2 are piped so as to be located on the downstream side in the inflow direction from the main shaft 9 (suction bell mouth 4) into the suction water tank 5. Moreover, the vertical pipes 18 </ b> A <b> 2 and 18 </ b> B <b> 2 are piped with reference to a reference line L that connects the axis of the suction bell mouth 4 and the corner on the downstream side in the inflow direction of the suction water tank 5. In the present embodiment, the vertical pipes 18A2 and 18B2 are piped so as to be positioned on the reference line L, but these pipes are preferably piped within a predetermined range (for example, ± 20 degrees) with respect to the reference line L. . As shown in FIGS. 1 and 2, the suction pipe mouth 18 and the impeller are arranged so that the vertical pipes 18A1 to 18B2 pass through the opening 2a from the horizontal pipes 17A and 17B and are located slightly below the impeller 11. It extends to a reduced diameter portion which is a connecting portion of the case 12.

  The vertical pipes 18A1 to 18B2 are provided with an opening / closing valve 19 including a normally closed electric butterfly valve so as to be positioned in the vicinity of the branch pipe portion 17b of the horizontal pipes 17A and 17B. The on-off valve 19 performs a cleaning process by the water tank cleaning device 16 by opening the valve and stops the cleaning process by closing the valve. The on-off valve 19 is not limited to the configuration provided in the vertical pipes 18A1 to 18B2, and may be provided, for example, in the connecting pipe portion 17a of the horizontal pipes 17A and 17B.

  The annular pipe 20 has an annular shape centered on the axis of the main shaft 9 and is connected to the lower ends of the vertical pipes 18A1 to 18B2 so as to surround the suction bell mouth 4 with a space therebetween. As a result, the annular pipe 20 has an annular center line located between the lower end of the impeller 11 and the suction port 4 a of the suction bell mouth 4. The annular pipe 20 is piped so that the outer diameter is larger than the outer diameter of the suction bell mouth 4 and is positioned on the extension line of the outer edge 15a of the underwater vortex preventing rib 15 inclined upward. A plurality (eight in this embodiment) of nozzles 21 are provided in the annular pipe 20 at equal intervals in the circumferential direction. These nozzles 21 are all disposed downward toward the bottom 5 a of the suction water tank 5. Moreover, as shown in FIG. 3, each nozzle 21 is provided so that it may be located at intervals with respect to the vertical pipes 18A1 to 18B2 located at intervals of 90 degrees. Further, each nozzle 21 protrudes radially outward in plan view so that a water flow is ejected in a direction away from the main shaft 9.

  The connecting rib 22 is for connecting the annular pipe 20 connected to the vertical pipes 18 </ b> A <b> 1 to 18 </ b> B <b> 2 and the suction bell mouth 4. The connecting ribs 22 of the present embodiment are provided at eight locations including a portion located on the radially inner side with respect to each of the vertical pipes 18A1 to 18B2 and a portion located therebetween. The connecting rib 22 also serves as a rectifying plate that prevents a swirling flow generated at the outer peripheral portion of the suction bell mouth 4.

  In the vertical shaft pump 1 configured as described above, the first water absorption path 23 defined by the underwater vortex preventing rib 15 is formed between the suction bell mouth 4 and the shaft center bell mouth 14, and the first shaft pump 1 is formed in the shaft center bell mouth 14. Two water absorption paths 24 are formed. Further, a sub-flow channel 25 is formed between the suction bell mouth 4 and the annular pipe 20 to form a sub-flow that flows downward and outward along the outer peripheral surface of the suction bell mouth 4. The sub-flow channel 25 is formed in a flow curve shape having no corners that expand outward in the radial direction by the shape of the suction bell mouth 4 having an arc shape and the annular pipe 20 having a circular cross section.

  The vertical shaft pump 1 performs normal drainage operation and management operation according to a program set in advance by the control device 26 based on detection values of predetermined sensors disposed in the suction water tank 5 and the casing 3.

  For example, when normal operation is not performed over a long period of time, the vertical pump 1 is operated not for draining the water in the suction water tank 5 but for the purpose of maintaining drainage performance (management operation). At the time of this management operation, in the case of this embodiment, the gate valve 7 is manually closed by an operator of the pump station, and when the control device 26 detects the valve closing of the gate valve 7, the vertical shaft pump 1 is started.

  When the vertical shaft pump 1 is activated, water in the suction water tank 5 is sucked from the suction port 4a of the suction bell mouth 4 through the first and second water suction passages 23 and 24. However, the pumping of water in the suction water tank 5 sucked into the casing 3 is blocked by the gate valve 7. When this state is detected by, for example, the pressure sensor 27, the control device 26 opens the on-off valve 19 and executes a cleaning process.

  When the on-off valve 19 is opened, the water in the suction water tank 5 is pumped from the casing 3 (discharge bend 6) to the annular pipe 20 via the horizontal pipes 17A and 17B and the vertical pipes 18A1 to 18B2. The water pumped to the annular pipe 20 is ejected from the nozzle 21 into the suction water tank 5 as shown in FIGS. That is, at the time of management operation, the water sucked into the casing 3 from the suction water tank 5 returns to the suction water tank 5 through the horizontal pipes 17A and 17B, the vertical pipes 18A1 to 18B2, the annular pipe 20 and the nozzle 21. Such a circulating flow of water passing through the casing 3 prevents an excessive temperature rise due to overheating of the vertical pump 1 during the management operation, for example, frictional heat generated in the bearings 10A to 10C.

  Since the nozzle 21 of the annular pipe 20 faces the bottom 5a of the suction water tank 5, foreign matter such as sediment and sand deposited on the bottom 5a of the suction water tank 5 is blown up by the water flow ejected from the nozzle 21 during the management operation. And floats in the water in the suction tank 5. The water ejected from the nozzle 21 of the annular pipe 20 collides with the bottom 5a of the suction water tank 5 or foreign matter deposited thereon, so that a complicated water flow is generated in the vicinity of the bottom 5a of the suction water tank 5 and is accumulated at the bottom 5a. It is possible to float the foreign matter that has been suspended more effectively. Since the head ratio Hb (partial flow rate region) during the management operation is generally higher than that during normal operation, which is the rated operation region or the excessive flow region, the pressure of water ejected from the nozzle 21 can be secured.

  As described above, after the foreign matter is sufficiently floated, the operator at the pump station manually opens the gate valve 7 and performs the normal operation of the vertical shaft pump 1. Thereby, the inside of the suction water tank 5 can be effectively cleaned by sucking the foreign matter together with water into the vertical shaft pump 1 and pumping it downstream. In this normal operation, the control device 26 closes the on-off valve 19 and stops the cleaning process.

  In the vertical shaft pump 1 of the present invention, it is not necessary to provide piping at the bottom 5 a of the suction water tank 5 separately from the casing 3, and for connecting the piping at the bottom 5 a of such suction water tank 5 to the upper end side of the casing 3. Since it is not necessary to provide a pipe line separately from the casing 3, the structure is simple. Moreover, when installing the casing 3 in the suction water tank 5, if it inserts into the opening part 2a from the upper part and it fixes to the casing 3 to the floor 2, the vertical piping 18A1-18B2 connected to the casing 3 and the vertical piping 18A1- The annular pipe 20 connected to 18B2 can also be installed in the suction water tank 5 together with the casing 3. In this respect, the vertical shaft pump 1 of the present embodiment is easy to install in the suction water tank 5.

  On the other hand, during normal operation, when the water in the suction tank 5 is drained to the vicinity of the impeller 11, an air suction vortex is likely to be generated in a region downstream of the suction bell mouth 4 in the inflow direction into the suction tank 5. To do. However, the vertical shaft 1 of the present embodiment is provided with the vertical pipes 18A2 and 18B2 of the water tank cleaning device 16 in the downstream area in the inflow direction in the suction water tank 5 where the air suction vortex is generated. And since these vertical piping 18A2 and 18B2 also make the effect | action which prevents a turning flow, generation | occurrence | production of the air suction vortex on the water surface can be suppressed effectively.

  Moreover, the annular pipe 20 of the water tank cleaning device 16 is connected to the outer peripheral portion of the suction bell mouth 4 by the connecting rib 22. Therefore, as shown in FIG. 4, the water flow from the water surface toward the suction port 4 a includes a main flow X that flows outside the annular pipe 20, and a secondary flow Y that flows through the subflow path 25 between the annular pipe 20 and the suction bell mouth 4. And is divided. The main flow X flows radially inward from the water surface toward the suction port 4 a of the suction bell mouth 4, and the side flow Y flows radially outward along the outer peripheral surface of the suction bell mouth 4. Therefore, the main flow X and the side flow Y disappear when they collide at the outer peripheral portion of the lower end of the suction bell mouth 4. Therefore, generation | occurrence | production of an air suction vortex can be prevented reliably. Furthermore, since the connection rib 22 of this embodiment plays the role of a current plate, the air suction vortex can be prevented from occurring by itself.

  As described above, in the vertical shaft pump 1 of the present invention, the vertical pipes 18A2 and 18B2 and the annular pipe 20 of the water tank cleaning device 16 also serve as a vortex generation prevention device that prevents the generation of air suction vortices. There is no need to provide it. Also in this respect, the structure is simple. Moreover, in the present embodiment, since the underwater vortex preventing rib 15 is provided in the suction bell mouth 4 and the annular pipe 20 is piped on the extension line of the outer edge 15a, an effective sub-flow path having a flow curve is obtained. 25 can be formed, and the generation of air suction vortices can be reliably suppressed. Further, the underwater vortex prevention rib 15 can reliably suppress underwater vortices generated in the water instead of the water surface.

  FIG. 5 shows the vertical shaft pump 1 of the second embodiment. In this second embodiment, the suction bell mouth 4 is not provided with the axial bell mouth 14 having the underwater vortex prevention rib 15. Moreover, it is set as the structure which connects the outer peripheral part of the pumping pipe 3a located in the upper side of the impeller case 12 in the casing 3, and the vertical piping 18A1-18B2 of the water tank cleaning apparatus 16 with the connection rib 22. FIG. The vertical pump 1 according to the second embodiment is different from the vertical pump 1 according to the first embodiment in that it does not have a function of suppressing the generation of submerged vortices, and otherwise obtains the same operation and effect. Can do.

  Specifically, during the management operation, the vertical pump 1 is overheated by the circulating flow from the suction water tank 5 through the casing 3, the horizontal pipes 17A and 17B, the vertical pipes 18A1 to 18B2, the annular pipe 20 and the nozzle 21 to the suction water tank 5. Is prevented. Moreover, foreign matters such as residue and sand that have accumulated on the bottom 5a of the suction water tank 5 are suspended in the water, and then the normal operation is performed, so that the foreign substances are pumped downstream together with the water, thereby effectively in the suction water tank 5. Can be cleaned.

  Further, during normal operation, when the water in the suction tank 5 is drained to the vicinity of the impeller 11, the vertical pipes 18A2 and 18B2 piped downstream in the inflow direction of the suction tank 5 prevent the swirling flow. It is possible to effectively suppress the generation of air suction vortices in the air. Moreover, the water flow from the water surface toward the suction port 4a is divided into a main flow X that flows outside the annular pipe 20 and a substream Y that flows through the subflow path 25 between the annular pipe 20 and the suction bell mouth 4, and sucks them. Since it can be made to collide and disappear at the lower end of the bell mouth 4, the generation of air suction vortex can be prevented.

  Thus, since the vertical pipes 18A2 and 18B2 and the annular pipe 20 of the water tank cleaning device 16 also serve as a vortex generation prevention device that prevents the generation of air suction vortices, there is no need to provide a separate vortex generation prevention device, and the structure is simple. It is. Further, if the casing 3 is inserted into the opening 2 a from above and fixed to the floor 2, the vertical pipes 18 </ b> A <b> 1 to 18 </ b> B <b> 2 connected to the casing 3 and the annular pipe 20 can be installed together in the suction water tank 5. Is easy to install.

  FIG. 6 shows the vertical shaft pump 1 of the third embodiment. In the third embodiment, the outer edge 15a of the underwater vortex preventing rib 15 is configured by a curved edge protruding radially outward from the suction port 4a which is the lower end edge of the suction bell mouth 4 in the first embodiment. And very different. Specifically, the outer edge 15a is formed by an arc edge having a predetermined curvature centered on the opposite upper side (for example, the upper left side in the case of the right outer edge 15a) so as to spread outward.

  The underwater vortex prevention rib 15 of the third embodiment is separate from the suction bell mouth 4 and the axial center bell mouth 14, and is formed by press forming or casting of a steel plate. Moreover, the connection rib 22 is integrally formed, and the notch part 30 which arrange | positions the annular piping 20 in the upper end outer side part is formed. Then, the suction bell mouth 4 is inserted into and joined to the groove 31 formed at the boundary between the underwater vortex preventing rib 15 and the connecting rib 22, the annular pipe 20 is disposed and joined to the notch 30, and the shaft center is formed on the inner edge. The bell mouth 14 is arranged and joined.

  In the vertical shaft pump 1, the underwater vortex preventing rib 15 protrudes outside the suction bell mouth 4, so that interference of other members with the suction bell mouth 4 and the annular pipe 20 can be suppressed. Further, since the plate-like underwater vortex prevention ribs 15 are arranged so as to form a + shape in plan view, the strength is improved while suppressing the fluid resistance when water is sucked from the suction port 4a. be able to. Therefore, the workability when installing the vertical shaft pump 1 in the pump station and the workability when disassembling can be improved.

  That is, as shown in FIG. 7, when installing or disassembling the vertical pump 1, the vertical pump 1 may be disconnected from the discharge pipe 8 and the drive mechanism 13 and placed horizontally on the base 32 of the bottom 5 a of the suction water tank 5. At this time, if the vertical shaft pump 1 is placed directly on the bottom portion 5a, the load is concentrated on the suction bell mouth 4 including the axial center bell mouth 14 and the annular pipe 20 and deforms. For this reason, conventionally, in a state where it is lifted, it has been laid down horizontally from the standing state or erected from the horizontal state.

  On the other hand, the vertical shaft pump 1 of the third embodiment is provided with a high-strength underwater vortex prevention rib 15 protruding outside the suction bell mouth 4. It can be laid down horizontally or erected from the horizontal position. Moreover, when the vertical shaft pump 1 is inserted into the opening 2a of the floor 2 from the suction water tank 5 side, the workability is improved by rotating or sliding the underwater vortex prevention rib 15 as a fulcrum. it can.

  As described above, the vertical shaft pump 1 of the third embodiment prevents the damage of the suction bell mouth 4 and the annular pipe 20 by the underwater vortex prevention rib 15 protruding outward from the suction bell mouth 4, Disassembly workability can be improved. Moreover, after closing the gate valve 7 and performing management operation, the cleaning process in the suction water tank 5 can be performed by opening the gate valve 7 and performing normal operation. Moreover, during normal operation, the same actions and effects as in the first embodiment can be obtained, such as preventing air suction vortices and underwater vortices.

  FIG. 8 shows a horizontal shaft pump 40 which is a pump of the fourth embodiment. The casing 41 of the horizontal shaft pump 40 includes a suction bell mouth 42 that extends upward from the vicinity of the bottom 5 a of the suction water tank 5, a discharge bend 43 that changes the upward water flow by the suction bell mouth 42 sideways, and the discharge bend 43 And an impeller case 44 for discharging the water flow from the horizontal direction.

  The suction port 42 a at the lower end of the suction bell mouth 42 is installed so as to face the bottom of the suction water tank 5 with a predetermined distance therebetween. In this embodiment, the discharge bend 43 is connected to the upper end of the suction bell mouth 42 via a straight tubular pumping pipe 45. The impeller case 44 has an elliptical spherical shape bulging outward in the radial direction, and a discharge pipe 47 provided with a gate valve 46 is connected to the discharge port 44a.

  A main shaft 48 extends through the casing 41 so as to extend in the horizontal (lateral) direction along the axis of the impeller case 44. The inner end portion of the penetrating main shaft 48 is rotatably supported by an underwater bearing 49 provided inside the impeller case 44. A drive mechanism 50 is connected to the end of the main shaft 48 that protrudes outward from the discharge bend 43. An impeller 51 is connected to the inner end side of the main shaft 48 located in the impeller case 44.

  The suction bell mouth 42 is provided with an axial bell mouth 52 integrally formed with an underwater vortex prevention rib 53, as in the first embodiment. The casing 41 is integrally provided with a water tank cleaning device 55 that also serves as a vortex generation prevention device.

  The water tank cleaning device 55 includes a branch pipe 56 connected to the impeller case 44. The branch pipe 56 is provided with a normally closed on-off valve 57. Further, the branch pipe 56 is branched downstream of the on-off valve 57 into four branch pipes 56a, to which vertical pipes 58A1 to 58B2 are connected, respectively.

  The vertical pipes 58A1 and 58B1 are piped to be located upstream of the suction bell mouth 42 in the water inflow direction, and the vertical pipes 58A2 and 58B2 are piped to be located downstream of the suction bell mouth 42 in the inflow direction. Yes. Further, the vertical pipes 58A1 to 58B2 extend to a portion positioned above the lower end edge of the suction bell mouth 42 with a predetermined interval. And one annular piping 59 is connected to the lower end of each vertical piping 58A1-58B2.

  The annular pipe 59 has an annular shape centered on the axis of the suction bell mouth 42, and is disposed so as to surround the suction bell mouth 4 with a space therebetween. In the annular pipe 59, nozzles 60 that can be sprayed downward toward the bottom 5a of the suction water tank 5 are provided at equal intervals in the circumferential direction.

  A plate-like connecting rib 61 extending in the axial direction is provided on the outer periphery of the suction bell mouth 42, and an annular pipe 59 is connected to the lower end of the connecting rib 61. The connecting rib 61 also serves as a rectifying plate that prevents a swirling flow generated at the outer peripheral portion of the suction bell mouth 42.

  In the horizontal axis pump 40 of the fourth embodiment, the gate valve 46 is closed and the management operation is performed, and then the gate valve 46 is opened and the normal operation is performed, whereby the water tank cleaning device 55 performs the suction water tank 5. The cleaning process inside can be executed. In addition, during normal operation, the vertical pipes 58A2 and 58B2, the annular pipe 59 and the connecting rib 61 can prevent the generation of air suction vortices, and the underwater vortex prevention rib 53 can prevent the generation of underwater vortices. Similar actions and effects can be obtained.

  In other words, the configuration of the present invention in which a water tank cleaning device including a vertical pipe and an annular pipe is provided can be applied regardless of the pump type such as a vertical pump or a horizontal pump, and the generation of air suction vortices is reliably prevented. The same action and effect can be obtained. Similarly, the configuration of the present invention in which an underwater vortex preventing rib is provided in the suction bell mouth is applicable regardless of the pump type, and the same action and effect of reliably preventing the generation of underwater vortex can be obtained. it can.

  The vertical shaft pump 1 of the present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

  For example, in each of the above-described embodiments, the four vertical pipes 18A1 to 18B2 and 58A1 to 58B2 are provided at intervals of 90 degrees, but the formation position and number can be changed as desired. In the above embodiment, the vertical pipes 18A2, 18B2, 58A2, and 58B2 on the downstream side in the inflow direction are arranged on the reference line L. However, the predetermined range with the reference line L as a reference according to the performance of the vertical pump 1 What is necessary is just to arrange | position within (for example +/- 20 degree). Similarly, the position and number of nozzles 21 and 60 can be changed as desired.

  Further, in the first and fourth embodiments in which the axial bell mouths 14 and 52 having the underwater vortex preventing ribs 15 and 53 are disposed, the suction bell mouths 4 and 42 and the annular pipes 20 and 59 are connected by the connecting ribs 22 and 61. Although comprised so that it may connect, you may comprise so that the casings 3 and 41 and vertical piping 18A1-18B2, 58A1-58B2 may be connected like 2nd Embodiment. Of course, in the second embodiment in which the axial bell mouth 14 is not provided, the suction bell mouth 4 and the annular pipe 20 may be connected by the connecting rib 22. Moreover, in the horizontal axis pump 40 of the fourth embodiment, the axial bell mouth 52 and the underwater vortex preventing rib 53 may be omitted.

  Moreover, in the said embodiment, although the water tank cleaning apparatus 16 was operated at the time of management operation, it is good also as a structure operated at the time of normal operation. For example, a water level sensor, a pressure sensor, a flow sensor or a vibration sensor is provided in the suction water tank 5 as a sensor for detecting the occurrence of air suction vortex, and when the sensor detects the occurrence of air suction vortex, the on-off valve 19 is set. It is good also as a structure made to open. In this way, the flow velocity of the secondary flow Y generated in the secondary flow path 25 by the circulating flow ejected from the nozzle 21 is increased, so that even if an air suction vortex is generated by the primary flow X, it can be reliably destroyed. it can. Therefore, generation | occurrence | production of an air suction vortex can be suppressed effectively.

DESCRIPTION OF SYMBOLS 1 ... Vertical shaft pump 3 ... Casing 4 ... Suction bell mouth 4a ... Suction port 5 ... Suction water tank 5a ... Bottom part 6 ... Discharge bend 6a ... Discharge port 7 ... Gate valve 8 ... Discharge pipe 9 ... Main shaft 11 ... Impeller 15 ... Underwater vortex Prevention rib 15a ... Outer edge 16 ... Water tank cleaning device 18A1 to 18B2 ... Vertical piping 19 ... Open / close valve 20 ... Annular piping 21 ... Nozzle 22 ... Connecting rib

Claims (9)

A suction bell mouth having a suction port opened facing the bottom in the suction water tank is disposed on the lower end side, a discharge pipe having a gate valve is connected to the upper end side, and on the inner end side that is penetrated In the casing where the main shaft to which the impeller is fixed is arranged,
Branched from the upstream side of the gate valve on the upper end side of the casing, and viewed from the upper side in the axial direction of the suction bell mouth so that the suction bell mouth is located downstream of the inflow direction of water into the suction water tank. A vertical pipe extending in the vertical direction along the casing toward the bottom of the suction water tank;
An annular pipe connected to the lower end side of the vertical pipe so as to surround the suction bell mouth with an interval, and having a plurality of nozzles facing the bottom of the suction water tank;
An on-off valve for executing or stopping a cleaning process for ejecting water in the casing into the suction water tank through the vertical pipe and the annular pipe;
A water tank cleaning device comprising:
The pump characterized by connecting the said casing and the said water tank cleaning apparatus with many connection ribs.   The pump according to claim 1, wherein the connecting rib is provided between the suction bell mouth and the annular pipe.   In the suction bell mouth, three or more underwater vortex preventing ribs projecting downward from the suction mouth of the suction bell mouth and extending radially outward from the axis line are arranged, and the outer edge of the underwater vortex prevention rib is provided. The pump according to claim 1 or 2, wherein the pump is inclined upward and outward, and the annular pipe is disposed on an extension line thereof.   The pump according to claim 3, wherein an outer edge of the underwater vortex preventing rib is a curved edge protruding radially outward from a lower end edge of the suction bell mouth.   The vertical pipe is arranged with reference to a reference line connecting an axis of the suction bell mouth and a downstream corner portion in the inflow direction of the suction water tank. The pump according to item.   The pump according to any one of claims 1 to 5, wherein the nozzle is outward in a plan view.   The said casing is a vertical shaft pump provided with the impeller case which arrange | positions the said impeller above the said suction bell mouth, and was arrange | positioned so that the said main shaft might be extended in a perpendicular direction. Item 7. The pump according to any one of items 6.   The pump according to claim 7, wherein the annular pipe is disposed between the impeller and a suction port of the suction bell mouth.   The said casing is a horizontal axis pump provided with the impeller case which arrange | positions the said impeller upstream from the said discharge pipe, and was arrange | positioned so that the said main axis might be extended in a horizontal direction. The pump according to claim 6.

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