JP2012177478A - Safety valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety valve that can be used in a vertical shaft pump.SOLUTION: The safety valve 23 is interposed in high pressure water piping 24 and has a vertical part 38 formed of a pipe erected in a vertical direction between an outlet and an inlet located below the outlet, a spindle 39 arranged in an axial center of the vertical part 38, a taper-shaped float 37 threaded through the spindle 39 so as to move in the vertical direction reducing in a diameter downward, and an orifice 42 located below the float 37 in the vertical part 38. A gap is not generated between the float 37 and the orifice 42 and fluid does not flow when the pressure obtained by dividing the in-water weight of the float 37 by the projecting area of the float 37 is greater than a difference between the inlet pressure of the orifice 42 and the outlet pressure of the orifice 42, the gap is generated between the float 37 and the orifice 42 and the fluid flows when the above pressure is not more than the difference between the inlet pressure and the outlet pressure.

Description

  The present invention relates to a safety valve.

  2. Description of the Related Art Conventionally, a vertical shaft pump is known in which a bypass pipe having a valve provided on the suction water tank side from a discharge pipe is provided. Such a vertical pump is configured so that water in the vertical pump can flow even in a management operation in which the discharge side is closed. In other words, during normal operation, the valve of the bypass pipe is closed to prevent water from flowing into the bypass pipe. However, during management operation not intended for drainage, the discharge side is closed to prevent overheating inside the pump. In order to reduce the load, water is allowed to flow to the suction tank through the bypass pipe.

  The management operation is usually time-limited and is not performed for a long time. In addition, simply returning water from the bypass pipe to the suction tank effectively removes sludge adhering to the bottom of the tank, transfers accumulated deposits, and cleans the suction tank by floating, etc. Can not do.

  For effective cleaning of the suction tank, a nozzle pipe that is horizontally disposed near the bottom of the bypass tank is connected to the lower end of the bypass pipe, and sludge that does not float in water is discharged from the bottom of the suction tank. Patent Document 1 discloses a pump facility provided with the above sewage pump separately from the vertical shaft pump. In this pump facility, sand and other inorganic substances such as sand that flow into the suction water tank and organic substances such as slag that float in the water are agitated and flowed with pressurized water sprayed from the nozzles provided in the nozzle piping, and sucked by the vertical shaft pump. Drain from the aquarium. The remaining non-floating material is accumulated by pressurized water from the nozzle and discharged from the suction water tank by the sewage pump.

  However, since the pump facility of Patent Document 1 is provided with a sewage pump in the suction water tank separately from the vertical shaft pump, the apparatus becomes complicated, and there is a problem that the cost and maintenance of the sewage pump are required.

JP 2006-200502 A

  This invention makes it a subject to provide the safety valve which can be used with the vertical shaft pump which can effectively clean a water absorption tank with a simple structure, without providing a complicated apparatus.

  The present invention is provided in a high-pressure water pipe, a vertical portion formed by a pipe rising in a vertical direction between an outlet and an inlet located below the outlet, and provided at the axial center of the vertical portion. A spindle-shaped float that is inserted into the spindle so as to be movable up and down, and has a diameter that decreases downward, and an orifice that is positioned below the float in the vertical portion, and the underwater weight of the float is If the pressure obtained by dividing by the projected area of the float is greater than the difference between the inlet pressure of the orifice and the outlet pressure of the orifice, there is no gap between the float and the orifice, no fluid flows, and the float When the pressure obtained by dividing the underwater weight by the projected area of the float is equal to or less than the difference between the inlet pressure and the outlet pressure, the gap between the float and the orifice Fluid flow gap is formed, to provide a safety valve.

  The upper end of the spindle is inserted into a hollow shaft disposed at the top of the vertical portion, and the hollow shaft is provided with a female screw portion, and the spindle is provided with a male screw portion that is screwed with the female screw portion, It is preferable that a stopper is fixed above the float of the spindle, and a moving range of the float can be regulated by adjusting a vertical position of the stopper by rotating a handle provided on the spindle.

  According to the present invention, by controlling the pressure in the high-pressure water pipe, the safety valve can be opened and closed, and the supply of high-pressure water through the high-pressure water pipe can be controlled.

The longitudinal cross-sectional view which shows the vertical shaft pump concerning this invention. The top view which shows a water absorption tank. The top view which shows the water absorption tank in another embodiment. Sectional drawing which shows a safety valve. Sectional drawing which shows the safety valve in another embodiment. Sectional drawing which shows the safety valve in another embodiment. The figure which shows the performance curve of a vertical shaft pump. The longitudinal cross-sectional view which shows the vertical shaft pump in another embodiment.

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

  FIG. 1 shows a vertical shaft pump (hereinafter simply referred to as a pump) 10 according to the present invention.

  The pump 10 is for draining water such as rainwater flowing into the water absorption tank 11 of the drainage pump station from an inflow side (upstream side) pipeline (not shown) to the downstream side, and includes a casing 12 extending in the vertical direction. ing. The water absorption tank 11 has a substantially rectangular parallelepiped space. The casing 12 includes a straight tubular pumping pipe 12a, a pump casing 12b connected to the lower end of the pumping pipe 12a, and a discharge elbow 12c connected to the upper end of the pumping pipe 12a and curved in the horizontal direction from the vertical direction. A suction bell 13 is provided at the lower end side of the pump casing 12 b, that is, at the lowermost part of the casing 12. The suction bell 13 opens downward, and its upper end side is connected to the lower end side of the pump casing 12b. The suction bell 13 has a diameter that increases from the upper end toward the lower end, and the lower end side tip portion 13a extends in the horizontal direction. The lower end side tip portion 13 a of the suction bell 13 forms a suction port 14.

  A discharge pipe 16 is connected to the discharge elbow 12 c through a discharge valve 15. An impeller 17 is disposed in the pump casing 12b. A main shaft 18 on which the impeller 17 is fixed to the lower end extends in the vertical direction and protrudes outside the casing 12. The main shaft 18 is supported by non-water-filled bearings 19 and 20 (hereinafter simply referred to as bearings) that function as radial bearings. The bearing 19 is attached to a rib 19a protruding from the inner surface of the pump casing 12b, and the bearing 20 is attached to a rib 20a protruding from the inner surface of the pumped-up pipe 12a. The upper end side of the main shaft 18 is connected to a drive mechanism 21 including a motor, a speed reduction mechanism, and the like schematically shown.

  A high-pressure water pipe 24 having a safety valve 23, which will be described in detail later, branches off from the discharge elbow 12c. A distributor 25 is provided on the opposite side of the discharge elbow 12c with respect to the safety valve 23 of the high-pressure water pipe 24. Four high-pressure water jet pipes 29 are branched from the distributor 25. That is, the distribution part 25 in this embodiment is a structure which distributes the water of the high pressure water piping 24 to the four high pressure water ejection pipes 29. Each tip of the four high-pressure water ejection pipes 29 has a nozzle 26, and the nozzle 26 is provided so as to be positioned on the bottom side of the water absorption tank 11. The ejection direction of the nozzle 26 has a horizontal component. In the present embodiment, the nozzles 26 are directed in three directions, an obliquely upward direction, a horizontal direction, and an obliquely downward direction, so that the water flow reaches a wide range on the bottom side of the pump 10. The horizontal components in the three directions of ejection are all in the same direction.

  FIG. 2 shows the water absorption tank 11 provided with the current plate 28. The current plate 28 extends in parallel with the side wall 27 b from the side wall 27 a of the water absorption tank 11 to the opposite side of the suction port 14 so as to be positioned below the suction port 14 of the pump 10. Of the nozzles 26a, 26b, 26c, and 26d of the four high-pressure water ejection pipes 29, the nozzles 26a and 26b are disposed on one side with the rectifying plate 28 in the water absorption tank 11 as a boundary, and the nozzles 26c and 26d It arrange | positions in the other side which made the baffle plate 28 in the water tank 11 into the boundary. The nozzle 26a is disposed on one end side of the rectifying plate 28 and in the vicinity of the portion where the rectifying plate 28 is connected to the side wall 27a, and the direction of the nozzle 26a is parallel to the rectifying plate 28 and from the one end side of the rectifying plate 28. It is the direction which is ejected to the other end side. The nozzle 26b is disposed on the other end side of the rectifying plate 28 and in the vicinity of the side wall 27b, and the direction of the nozzle 26b is jetted from the other end side of the rectifying plate 28 to the one end side in parallel with the rectifying plate 28. Direction. The nozzles 26c and 26d are also arranged with the same positional relationship as the nozzles 26a and 26b. The positional relationship between the nozzles 26a and 26b in the direction orthogonal to the direction from the one end side to the other end side of the rectifying plate 28 may be opposite to each other. Similarly, the positional relationship between the nozzles 26c and 26d may be reversed.

  FIG. 3 shows the water absorption tank 11 in which the current plate is not provided. The nozzle 26e is disposed in the vicinity of a portion where the side wall 27a and the side wall 27b are connected. The direction of the nozzle 26e is a direction in which the horizontal component of the high-pressure water ejected from the nozzle 26e is ejected in parallel with the side wall 27b from a portion where the side wall 27a and the side wall 27b are connected. The nozzle 26f is disposed in the vicinity of the side wall 27b on the side opposite to the nozzle 26e with respect to the suction port 14. The direction of the nozzle 26f is a direction in which the horizontal component of the high-pressure water ejected from the nozzle 26f is ejected in a direction opposite to the direction from the nozzle 26f toward the side wall 27b. The nozzle 26g is disposed in the vicinity of the side wall 27c in the ejection direction of the nozzle 26f. The direction of the nozzle 26g is a direction in which the horizontal component of the high-pressure water ejected from the nozzle 26g is ejected in parallel with the side wall 27c toward the portion where the side wall 27a and the side wall 27c are connected. The nozzle 26h is disposed in the vicinity of a portion where the side wall 27a and the side wall 27c are connected. The direction of the nozzle 26h is a direction in which the horizontal component of the high-pressure water ejected from the nozzle 26h is ejected in parallel to the side wall 27a from the portion where the side wall 27a and the side wall 27c are connected. That is, the nozzle 26f is disposed in front of the ejection direction of the nozzle 26e, the nozzle 26g is disposed in front of the ejection direction of the nozzle 26f, the nozzle 26h is disposed in front of the ejection direction of the nozzle 26g, A nozzle 26e is disposed in front of the ejection direction. In the present embodiment, the directions of the four nozzles 26e, 26f, 26g, and 26h are the same as the rotation direction of the impeller 17 of the pump 10.

  A filter 30 is provided on the inner peripheral surface of the discharge elbow 12 c where the high-pressure water pipe 24 branches.

  An intake hole 32 is formed in the uppermost portion of the discharge elbow 12 c, and an intake pipe 33 is connected to the intake hole 32. The intake pipe 33 is communicated with the atmosphere via a vacuum break valve 34. The vacuum breaker valve 34 is a check valve. When the pressure in the casing 12 becomes negative, the valve is opened only in the direction in which air is sucked into the casing 12 from the atmosphere communication side.

  The control device 36 is connected to the discharge valve 15 of the pump 10. The controller 36 controls the opening and closing of the discharge valve 15 of the pump 10.

  Next, the safety valve 23 of the high pressure water pipe 24 will be described. 4 to 6 show an embodiment of the safety valve 23. FIG. FIG. 4 shows a check valve using a tapered float 37. The inlet of the safety valve 23 (the part to which the high pressure water pipe 24 from the discharge elbow 12c side is connected) is located below the outlet (the part to which the high pressure water pipe 24 to the distribution unit 25 side is connected). The safety valve 23 includes a vertical portion 38 that rises in a vertical direction between the inlet and the outlet and is formed by a pipe having a circular cross section in the horizontal direction. The inlet, the vertical portion 38, and the outlet are connected in a crank shape. Yes. A spindle 39 is provided at the axial center of the pipe constituting the vertical portion 38. A through hole 40 penetrating in the axial direction of the taper is provided at the axial center of the tapered float 37. A bearing 41 is provided in the through hole 40. The tapered float 37 is inserted into the spindle 39 via the bearing 41 so as to be tapered toward the bottom surface side. The tapered float 37 can be moved up and down on the spindle 39. The vertical portion 38 is provided with an orifice 42 having a size that allows the tapered float 37 to be fitted in the tapered portion. When the tapered portion of the tapered float 37 is fitted into the orifice 42, the vertical portion 38 of the safety valve 23 is sealed. A portion of the safety valve 23 where the lower end of the spindle 39 is supported is provided with a hunting preventing damper 44 that surrounds the portion and supports the bottom surface of the tapered float 37.

  5, the upper end of the spindle 39 of FIG. 4 is provided with a handle 46 at the upper end and a stopper 47 fixed to the lower end, and the safety valve 23 inserted into the hollow shaft 48 penetrating the top surface of the vertical portion 38 is provided. Show. A male screw portion 50 is provided on the outer peripheral surface of the hollow shaft 48, and a female screw portion 51 that is screwed with the male screw portion 50 is provided on the top surface of the vertical portion 38. The upper end of the spindle 39 is inserted into the hollow shaft 48, and the male screw portion 50 of the hollow shaft 48 is supported by screwing with the female screw portion 51 of the vertical portion 38.

  6 shows a tapered float 37 and an orifice 42 of the safety valve 23 in FIG. 5 with a cylindrical float 53 and an inclined portion 54 that becomes smaller as the circular cross-sectional shape of the inner peripheral surface of the vertical portion 38 decreases downward. The safety valve 23 changed to the orifice 55 provided above is shown. The safety valve 23 changes the size of the gap formed by the bottom surface of the cylindrical float 53 and the inclined portion 54 when the cylindrical float 53 moves up and down on the spindle 39 in a range where the inclined portion 54 of the orifice 55 is present. It is like that. The bottom surface of the float 53 is sized to be supported at the lowermost end of the inclined portion 54.

  FIG. 7 shows an example of the flow rate-lift curve (HQ curve) of the pump 10 together with the pump efficiency η and the shaft horsepower L. In FIG. 7, the horizontal axis represents the ratio of the flow rate Q to the optimum flow rate Qopt (Q / Qopt), and the vertical axis represents the ratio of the lift head H to the optimal lift Hopt (H / Hopt). The range where Q / Qopt is about 0.6 to 1.2 is the rated operation region, the Q / Qopt is about 1.2 or more is the excessive flow region, and the Q / Qopt is about 0.6 or less is the partial flow region.

  Next, the operation of the pump 10 according to the present invention will be described. When the pump 10 is started based on rainfall information or the like, for example, at a standby water level lower than the suction port 14 of the suction bell 13 (the water tank 11 may have no water), water is contained in the casing 12. Since it does not exist, the impeller 17 rotates in the air (idling operation). At this time, the discharge valve 15 of the pump 10 is in the open state, as before the start. When the water level in the water absorption tank 11 rises and reaches the lower end of the impeller 17, the water in the water absorption tank 11 is sucked up by the rotation of the impeller 17, and the suction bell 13, the pump casing 12b, the pumping pipe 12a, and the discharge elbow 12c. The water is drained to the discharge pipe 16 via the (normal operation).

  When the drainage is finished, the operation of the pump 10 is stopped. The water inside the casing 12 falls. Therefore, the inside of the casing 12 is not filled with water until the next start. If there is no water inside the casing 12 and water is attached to the bearings 19 and 20 or the like, or if the inside of the casing 12 is humid for a long time, air is applied to the metal surfaces of the bearings 19 and 20 or the like. Rust is likely to occur due to the oxygen in the inside. Therefore, when not used for a certain period of time, a management operation is performed to maintain the performance of the bearings 19 and 20 such as rust prevention.

  Since the management operation of the pump 10 is not intended for drainage, the operation is performed with the discharge valve 15 closed so as to reduce the energy consumed for pumping as much as possible.

  At that time, the safety valve 23 of the high-pressure water pipe 24 is opened. By doing so, water can flow into the high-pressure water pipe 24. Thereby, since the water inside the pump 10 can be flowed, it can be avoided that the heat generated by the rotation of the impeller 17 of the main shaft 18 is accumulated in the water inside the pump 10 and the water temperature rises. Further, by causing the water of the pump 10 to flow, the discharge side of the pump 10 is closed and the water is filled in the pump 10 without being fed, so that the drive mechanism 21, the bearings 19, 20 and the blades are present. It is possible to avoid maintaining a large load on the vehicle 17.

  The safety valve 23 of the high-pressure water pipe 24 is opened and closed by the inlet pressure P1 of the orifices 42 and 55 of the safety valve 23 on the high-pressure water pipe 24, the pressure Pf due to the weight of the floats 37 and 53 moving up and down on the spindle 39, and the safety valve. 23 in accordance with the relationship with the outlet pressure P2 of the orifices 42 and 55. The pump 10 of the present embodiment changes the pumping amount in a state where the discharge valve 15 of the pump 10 is closed, so that the desired amount can be obtained within a range indicated by the flow rate-head curve (HQ curve) of the pump 10 in FIG. It is used to open the safety valve 23 by obtaining water of water pressure.

  In order to prevent the safety valve 23 from being opened during rated operation, Hb corresponding to the pressure at which the safety valve 23 opens (corresponding flow rate Qb) is a portion where water having a higher pressure than the rated operation range shown in FIG. 7 is obtained. Set in the flow area.

  In the pump 10 showing the flow rate-head curve (HQ curve) described above, when Q / Qopt is operated in the rated operation region or the excessive flow region, Q / Qopt takes a value larger than Qb, so H / Hopt is It becomes less than Hb (first pressure corresponding to normal operation), and water having a desired water pressure cannot be obtained. Therefore, the water at the inlet of the safety valve 23 cannot be used for opening the valve. Therefore, when the pump 10 is operated in the rated operation region or the excessive flow region, the safety valve 23 is not opened.

  When operating in a range where Q / Qopt takes a value larger than Qb in the partial flow region, H / Hopt is less than Hb as in the rated operation region or excessive flow region, and the desired water pressure You can't get water. Therefore, the water at the inlet of the safety valve 23 cannot be used for opening the valve.

  When operating in a range where Q / Qopt is greater than 0 and equal to or less than Qb in the partial flow region, H / Hopt is equal to or higher than Hb (second pressure corresponding to the management operation) and is desired. Can be obtained. That is, in order to open the safety valve 23 of the high-pressure water pipe 24, the operation is performed in a range where Q / Qopt takes a value greater than 0 and equal to or less than Qb in the partial flow region.

  The management operation of the pump 10 is performed by operating the pump 10 in a state where the discharge valve 15 of the pump 10 is closed and the Q / Qopt of the partial flow region is greater than 0 and equal to or less than Qb. Do. As a result, the safety valve 23 of the high-pressure water pipe 24 can be opened, and the high-pressure water can flow toward the nozzle 26.

  If the water flowing through the high-pressure water pipe 24 by simply opening the safety valve 23 is simply returned to the water absorption tank 11, energy is lost due to pumping, which is a loss. In order to reduce this loss, when water is dropped, the potential energy of the water is converted into kinetic energy, and a water flow is generated from the nozzle 26 and used.

  A mechanism for opening and closing the safety valve 23 will be described. The inlet pressure P1 of the orifices 42 and 55 of the safety valve 23 on the high-pressure water pipe 24, the pressure Pf due to the weight of the floats 37 and 53 moving up and down on the spindle 39, and the outlet pressure P2 of the orifices 42 and 55 of the safety valve 23 The safety valve 23 is opened and closed according to the relationship. Since the inlet pressure P1 of the orifices 42 and 55 of the safety valve 23 transmitted from the discharge elbow 12c to the high pressure water pipe 24 is substantially the same as the pressure of the discharge elbow 12c, the inlet pressure P1 is controlled by controlling the water pressure in the above-described manner. Can be controlled easily. When the weight of the floats 37 and 53 is Wt and the buoyancy is Ww, the underwater weight Wf of the floats 37 and 53 is the difference between Wt and Ww. The pressure Pf due to underwater weight of the floats 37 and 53 is obtained by dividing Wf by A, where A is the projected area of the floats 37 and 53.

  If the pressure Pf due to the underwater weight of the floats 37 and 53 is larger than the difference between the inlet pressure P1 and the outlet pressure P2 (P1> P2), no force to push up against the underwater weight of the floats 37 and 53 is generated. , 53 and the orifices 42, 55, no gap is generated and no fluid flows.

  When the pressure Pf due to underwater weight of the floats 37 and 53 is the same as the difference between the inlet pressure P1 and the outlet pressure P2 (P1> P2), a gap is generated between the floats 37 and 53 and the orifices 42 and 55. Begins to flow.

  When the pressure Pf due to the weight of the floats 37 and 53 in water is smaller than the difference between the inlet pressure P1 and the outlet pressure P2 (P1> P2), a gap is generated between the floats 37 and 53 and the orifices 42 and 55, and the fluid flows. . The floats 37 and 53 move upward as the difference between the inlet pressure P1 and the outlet pressure P2 increases. 7 is determined by the shape and weight of the floats 37 and 53 of the safety valve 23, the diameters of the orifices 42 and 55, and the like. In the pump 10, by selecting an appropriate parameter, the safety valve 23 is closed at the first pressure that is the pressure during normal operation in the high-pressure water pipe 24, and the first pressure that is the pressure during management operation. The safety valve 23 can be opened with the second pressure higher than that, and the high-pressure water can flow through the high-pressure water pipe 24. In this way, by controlling the pressure in the high-pressure water pipe 24, the safety valve 23 can be opened and closed, and the supply of high-pressure water through the high-pressure water pipe 24 can be controlled.

  The safety valve 23 of FIGS. 5 and 6 can regulate the range of movement of the floats 37 and 53 by rotating the handle 46 and adjusting the vertical position of the stopper 47 in advance. The flow rate can be adjusted.

  High-pressure water flowing through the high-pressure water pipe 24 is supplied from the casing 12 of the pump 10, sent to the high-pressure water ejection pipe 29 through the distributor 25, and ejected from the nozzle 26. Jet water (high-pressure water) is ejected from the nozzle 26 in three directions, diagonally upward, horizontal, and diagonally downward. Since all the three horizontal components of the jet are in the same direction, it is possible to generate a water flow whose direction is constant in the horizontal direction. Since the nozzle 26 is also ejected obliquely downward toward the bottom surface of the water absorption tank 11, force can be applied to the sludge and the like attached to the bottom surface by the water flow along the bottom surface, and the water can be peeled off. And sludge etc. which peeled with sludge etc. which accumulated on the bottom face floats in water with jet water.

  As shown in FIG. 2, in the water absorption tank 11 in which the nozzles 26 a, 26 b, 26 c, and 26 d are arranged, the direction of the nozzles 26 a and 26 b is 180 in the region partitioned by the rectifying plate 28 in the water absorption tank 11. The nozzles 26a and 26b are different from each other in a direction orthogonal to the direction of the nozzles 26a and 26b. Therefore, a substantially elliptical swirl flow in which the deviation in the direction orthogonal to the direction of the nozzles 26a and 26b becomes the short axis of the substantially ellipse and the deviation in the direction parallel to the direction of the nozzles 26a and 26b becomes the major axis of the substantially ellipse. The nozzle 26a and the nozzle 26b can be generated around the middle point. The swirling direction of the swirling flow is the same as the direction of the nozzles 26a and 26b. The nozzles 26c and 26d are the same as the nozzles 26a and 26b.

  As shown in FIG. 3, in the water absorption tank 11 in which the nozzles 26 are arranged, the water flow ejected by one nozzle 26, for example, the nozzle 26e, reaches the vicinity of the nozzle 26f in front of the ejection direction. The water flow that reaches the vicinity of the nozzle 26f is pushed out by the water flow ejected by the nozzle 26f. The water flow pushed out by the water flow and integrated with the water flow reaches the vicinity of the nozzle 26g, and is similarly pushed out by the water flow ejected by the nozzle 26g. In this manner, a swirling flow around the suction port 14 of the pump 10 can be generated in the water absorption tank 11 by the four nozzles 26e, 26f, 26g, and 26h. In this embodiment, since the directions of the nozzles 26e, 26f, 26g, and 26h are the same as the direction in which the impeller 17 rotates, the jet 10 is ejected from the nozzles 26e, 26f, 26g, and 26h. The rotational resistance of the impeller 17 can be reduced.

  Sludge or the like suspended by jet water circulates around the suction port 14 on the above-described swirling flow. Thereafter, when the operation of the pump 10 is stopped, high-pressure water cannot be obtained inside the high-pressure water pipe 24, and the safety valve 23 is closed. As a result, jet water is no longer ejected from the nozzle 26, and eventually the swirl flow disappears. Then, sludge or the like that circulates around the suction port 14 by the swirling flow accumulates in the tank bottom near the center of the swirling flow.

  Next, when the pump 10 is started, sludge accumulated on the bottom surface of the water absorption tank 11 is sucked up together with water from the suction port 14 of the pump 10 and discharged from the discharge side of the pump 10. In this way, the inside of the water absorption tank 11, particularly the bottom surface can be cleaned.

  That is, according to the present invention, high-pressure water supplied from the inside of the casing 12 of the pump 10 through the high-pressure water pipe 24, the distributor 25, and the high-pressure water ejection pipe 29 is ejected from the nozzle 26, A swirling flow can be generated. Since the nozzle 26 of the high-pressure water jet pipe 29 is arranged so that the swirling flow is generated around the suction port 14 of the pump 10, sludge accumulated on the bottom surface of the water absorption tank 11 is placed on the swirling flow and the suction port. 14 and can be easily discharged to the discharge side of the pump 10. Thereby, the water absorption tank 11 can be effectively cleaned with a simple configuration without providing a complicated device.

  Further, by providing a filter 30 on the inner peripheral surface of the casing 12 where the high-pressure water pipe 24 branches, it is possible to prevent sludge or the like from entering the high-pressure water pipe 24 when water is supplied to the high-pressure water pipe 24. The clogging of the high-pressure water pipe 24 can be prevented. Further, sludge adhering to the filter 30 can be easily washed away by water passing through the surface of the filter 30 during normal drainage operation, and the filter 30 can be easily washed. As a result, maintenance work such as replacement due to clogging of the filter 30 can be reduced.

  The present invention is not limited to the embodiment, and various modifications are possible. For example, as shown in FIG. 8, when the inside of the casing 12 becomes negative pressure, the intake pipe 58 provided with a vacuum break valve 57 that opens only in the direction in which air is sucked into the casing 12 from the atmosphere communication side is discharged. You may make it branch from the high pressure water piping 24 between the elbow 12c and the safety valve 23. FIG. By doing so, it is not necessary to provide the intake elbow 12c with the intake hole 32 for the intake pipe 33. In addition, a silencer 59 may be provided at a portion of the intake pipe 58 that communicates with the atmosphere on the tip side of the vacuum breaker valve 57. Moreover, you may provide the pit which accumulate | stores the sludge etc. which floated on the bottom face of the water absorption tank 11 focusing on the suction inlet 14 of the pump 10. FIG. Further, the arrangement of the nozzle 26 may be any arrangement as long as it generates a swirling flow around the suction port 14 below the water absorption tank 11.

DESCRIPTION OF SYMBOLS 10 Vertical shaft pump 11 Water absorption tank 12 Casing 12a Pumping pipe 12b Pump casing 12c Discharge elbow 13 Suction bell 13a Lower end side tip 14 Suction port 15 Discharge valve 16 Discharge pipe 17 Impeller 18 Main shaft 19, 20 Non-water-filled bearing
19a, 20a Rib 21 Drive mechanism 23 Safety valve 24 High pressure water piping 25 Distribution part 26, 26a, 26b, 26c, 26d, 26e, 26f, 26g, 26h Nozzle 27, 27a, 27b, 27c Side wall 28 Rectifier plate 29 High pressure water ejection pipe DESCRIPTION OF SYMBOLS 30 Filter 32 Intake hole 33,58 Intake pipe 34,57 Vacuum break valve 36 Control apparatus 37,53 Float 38 Vertical part 39 Spindle 40 Through-hole 41 Bearing 42,55 Orifice 44 Damper 46 Handle 47 Stopper 48 Shaft 50 Male thread part 51 Female thread part 54 Inclined part 59 Silencer

Claims (2)

A vertical section formed by a pipe interposed in the high-pressure water pipe and rising in the vertical direction between the outlet and the inlet located below the outlet;
A spindle provided at the axial center of the vertical portion;
A tapered float that is inserted through the spindle so as to move up and down and shrinks downward;
An orifice located below the float in the vertical portion, and
If the pressure obtained by dividing the underwater weight of the float by the projected area of the float is larger than the difference between the inlet pressure of the orifice and the outlet pressure of the orifice, there is no gap between the float and the orifice. No fluid flows,
When the pressure obtained by dividing the underwater weight of the float by the projected area of the float is equal to or less than the difference between the inlet pressure and the outlet pressure, a fluid flows with a gap formed between the float and the orifice. safety valve. The upper end of the spindle is inserted into a hollow shaft arranged at the top of the vertical part,
The hollow shaft is provided with a female screw portion, and the spindle is provided with a male screw portion that engages with the female screw portion,
A stopper is fixed above the float of the spindle,
The safety valve according to claim 1, wherein a handle provided on the spindle is rotated to adjust a vertical position of the stopper so that a movement range of the float can be regulated.

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