JP2017201136A - pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump capable of preventing occurrence of flow loss caused by sudden expansion of a flow passage.SOLUTION: A pump includes a pump casing having a suction port and a discharge port, a rotating shaft arranged in the pump casing, and a plurality of impellers fixed to the rotating shaft and arranged in plural stages. The pump casing includes a discharge casing having the discharge port, and the pump has a check valve which prevents backflow of fluid sent into the discharge casing through the impellers. The check valve includes a valve seat, and a valve element which can be lifted and lowered between a maximum valve open position where the valve element is separated furthest away from the valve seat and a valve close position where the valve element is seated on the valve seat. The valve element has a projection projecting toward an end of the rotating shaft, and the projection is overlapped with a peripheral surface of the end of the rotating shaft in the maximum valve open position.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pump, and more particularly, to a pump provided with a liftable check valve.

  FIG. 7 shows an example of a multistage pump as a conventional pump. Note that the left half of FIG. 7 is a side view and the right half is a cross-sectional view. In FIG. 7, 21 is a submersible motor, 25 is a suction casing having a suction port 22, 23 is an impeller attached to a rotating shaft 26, 24 is an intermediate casing, and 11 is a discharge casing having a discharge port 16. When the pump is in operation, each impeller 23 is rotated by the rotation of the rotary shaft 26 of the pump connected to the submersible motor 21. Water sucked from the suction port 22 by the rotation of the impeller 23 is sent into the discharge casing 11 through the intermediate casing 24.

Utility model application publication Sho 62-117363

  8A and 8B show the configuration around the flow path from the intermediate casing 24 toward the discharge casing 11. FIG. 8A shows a state when the pump is operating, and FIG. 8B shows a state when the pump is stopped. In the discharge casing 11, a valve body 14 that is supported by the valve rod 13 and the coil spring 15 so as to be movable up and down in the discharge casing 11 is disposed. The valve body 14 is formed of, for example, cast iron or bronze casting. The valve body 14 and the valve seat 12 having a rubber seat surface attached to the intermediate casing 24 constitute a check valve for preventing water falling in the pipe when the pump is stopped. The coil spring 15 is disposed between the inner wall surface of the discharge casing 11 and the valve body 14 and biases the valve body 14 toward the valve seat 12.

  When the operation of the pump is started, the water sucked by the rotation of the impeller 23 rises in the intermediate casing 24 along the guide vane 27 while recovering the pressure. The valve body 14 is separated from the valve seat 12 against the biasing force of the coil spring 15 by the pressure of the sucked water. This opens the check valve. The valve body 14 can be raised in the discharge casing 11 to a predetermined maximum valve opening position shown in FIG. 8A while being guided by the valve rod 13. After the check valve is fully opened, the valve open state is maintained by the collision energy of water.

  As shown in FIG. 8A, when the valve body 14 is in the maximum valve opening position, a large space (region A in the figure) is formed in front of the valve body 14. Accordingly, the flow path of the water is expanded rapidly, which causes various loss of flow such as separation of the flow of water and generation of vortices.

  On the other hand, when the pump is stopped, as shown in FIG. 8B, the valve element 14 is seated on the valve seat 12 by the action of the coil spring 15. At this time, foreign matter such as sand contained in the water is removed from the rotary shaft 26. There is a risk of entering a space (region B in the figure) between the end of the bearing and the bearing 28 fixed to the intermediate casing 24. When foreign matter enters the space between the rotary shaft 26 and the bearing 28, the bearing 28 is damaged. Further, since the rotation of the rotary shaft 26 is hindered by foreign matter, the pump efficiency is lowered.

  An object of one embodiment of the present invention is to solve at least one of the above problems.

  According to one embodiment of the present invention, a pump casing having a suction port and a discharge port, a rotating shaft disposed in the pump casing, and a plurality of impellers fixed to the rotating shaft and disposed in multiple stages, The pump casing includes a discharge casing having a discharge port, and the pump is further configured to prevent reverse flow of the fluid fed into the discharge casing via the plurality of impellers. The check valve includes a valve seat, and a valve body that can be raised and lowered between a maximum valve opening position that is maximally spaced from the valve seat and a valve closing position that is seated on the valve seat. The valve body includes a protruding portion that protrudes toward the end of the rotating shaft, and the protruding portion is configured to overlap the peripheral surface of the end of the rotating shaft at the maximum valve opening position. A pump is provided. According to this configuration, even when the valve body is at the maximum valve opening position, it is possible to prevent a rapid expansion of the flow path due to the presence of the protruding portion. Therefore, it is possible to prevent the occurrence of flow loss during operation of the pump.

  According to one embodiment of the present invention, the projecting portion includes a hollow portion that opens toward the end portion of the rotating shaft and has an inner diameter that is larger than the outer diameter of the end portion of the rotating shaft. It is comprised so that it may overlap with the outer peripheral surface of the edge part of a rotating shaft. According to this configuration, even when the valve body is at the maximum valve opening position, it is possible to prevent a rapid expansion of the flow path due to the presence of the protruding portion. Therefore, it is possible to prevent the occurrence of flow loss during operation of the pump. Further, when the pump is stopped, the protruding portion of the valve body at the valve closing position overlaps with the outer peripheral surface of the end portion of the rotating shaft, so that foreign matter can be prevented from entering between the rotating shaft and the bearing. Therefore, there is no risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

  According to an embodiment of the present invention, the end of the rotating shaft includes a recess that opens toward the projecting portion and has an inner diameter that is larger than the outer diameter of the projecting portion. It is comprised so that it may overlap with a surrounding surface. According to this configuration, even when the valve body is at the maximum valve opening position, it is possible to prevent a rapid expansion of the flow path due to the presence of the protruding portion. Therefore, it is possible to prevent the occurrence of flow loss during operation of the pump.

  According to one embodiment of the present invention, the end of the rotating shaft includes an enlarged portion that is enlarged radially outward, and the recess is formed in the enlarged portion. According to this configuration, even when the valve body is at the maximum valve opening position, it is possible to prevent a rapid expansion of the flow path due to the presence of the protruding portion. Therefore, it is possible to prevent the occurrence of flow loss during operation of the pump. Further, when the pump is stopped, the enlarged portion at the end of the rotating shaft can prevent foreign matter from entering between the rotating shaft and the bearing. Therefore, there is no risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

  According to one embodiment of the present invention, the annular member is attached to the end of the rotating shaft, and the protruding portion is the inner peripheral surface of the recess defined by the inner peripheral surface of the annular member and the end surface of the rotating shaft. It is comprised so that it may overlap. According to this configuration, even when the valve body is at the maximum valve opening position, it is possible to prevent a rapid expansion of the flow path due to the presence of the protruding portion. Therefore, it is possible to prevent the occurrence of flow loss during operation of the pump. Further, when the pump is stopped, the annular member attached to the end of the rotating shaft can prevent foreign matter from entering between the rotating shaft and the bearing. Therefore, there is no risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

  According to one embodiment of the present invention, the pump includes a valve stem that is fixed to the valve body and supports the valve body so as to be movable up and down. According to this structure, a valve body can be raised / lowered stably with respect to the rotating rotating shaft.

  According to an embodiment of the present invention, the pump further includes a motor coupled to the rotating shaft.

  According to one embodiment of the present invention, it is possible to provide a pump capable of preventing the occurrence of a flow loss due to a sudden expansion of a flow path. Moreover, according to one embodiment of the present invention, it is possible to provide a pump that is free from the risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

It is the schematic which shows an example of the pump by 1st embodiment of this invention. It is sectional drawing which shows the valve body of the non-return valve used in 1st embodiment of this invention. It is a figure which shows an example of an effect | action of the valve body of FIG. It is a figure which shows an example of an effect | action of the valve body of FIG. It is a figure which shows 2nd embodiment of this invention. It is a figure which shows 3rd embodiment of this invention. It is a figure which shows 4th embodiment of this invention. It is a figure which shows an example of the conventional pump. It is a figure which shows the valve body of the non-return valve used for the conventional pump. It is a figure which shows the valve body of the non-return valve used for the conventional pump.

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

  FIG. 1 is a diagram showing an example of a pump according to the first embodiment of the present invention. 1 is different from the conventional example shown in FIG. 7 only in the configuration of the valve body of the check valve disposed in the discharge casing 11. FIG. 2 is a cross-sectional view showing a configuration of the valve body 44 of the check valve used in the embodiment of the present invention. Since other configurations are the same as those of the conventional example shown in FIGS. 7 to 8B, the same portions are denoted by the same reference numerals and description thereof is omitted.

  Similar to the conventional valve body 14, the valve body 44, together with the valve seat 12 attached to the intermediate casing 24, constitutes a check valve for preventing water falling in the pipe when the pump is stopped. Further, like the conventional valve body 14, the valve body 44 can be formed of cast iron, bronze casting or the like. The valve body 44 includes an annular portion 50 formed in a generally bowl shape including an abutting surface capable of abutting against the valve seat 12, and a protrusion protruding from an approximate center of the annular portion 50 toward the end of the rotary shaft 26. The shape part 51 is provided. In FIG. 2, 52 is a spring receiving groove that receives one end of the coil spring 15 that supports raising and lowering of the valve body 44. The other end of the coil spring 15 is disposed in an annular step formed on the inner wall surface of the discharge casing 11. In FIG. 2, reference numeral 53 denotes a recess to which one end of the valve rod 43 that supports the valve body 44 is fixed. The valve rod 43 and the valve body 44 may be integrated. Further, the outer peripheral end portion of the annular portion 50 is bent inward of the valve body 44 so as to form an end surface that can contact the inner wall surface of the discharge casing 11.

  The valve body 44 can be raised and lowered between a maximum valve opening position that is maximally spaced from the valve seat 12 and a valve closing position that is seated on the valve seat 12. The protruding portion 51 is configured to overlap the peripheral surface of the end portion of the rotating shaft 26 at the maximum valve opening position and the valve closing position of the valve body 44. In other words, the projecting portion 51 has a length in the axial direction (vertical direction in the figure) sufficient to overlap the peripheral surface of the end of the rotary shaft 26 at the maximum valve opening position and the valve closing position of the valve body 44. doing. Here, the “end portion of the rotating shaft 26” means a portion of the rotating shaft 26 and a portion above the bearing 28 disposed at a position closest to the discharge casing 11.

In the present embodiment, the protruding portion 51 is cylindrical. Specifically, the protruding portion 51 includes a hollow portion 55 that opens toward the end portion of the rotating shaft 26 and has an inner diameter larger than the outer diameter of the end portion of the rotating shaft 26. The hollow portion 55 can overlap the peripheral surface of the end portion of the rotating shaft 26. In other words, the inner peripheral surface of the hollow portion 55 is configured to overlap the outer peripheral surface of the end portion of the rotating shaft 26. In this embodiment, the cavity 56 of the hollow portion 55 extends toward the inside of the valve body 44 beyond the bottom surface of the annular portion 50 (in other words, the surface on the valve seat 12 side). The axial length is not limited to the illustrated example. Further, the entire inner peripheral surface of the hollow portion 55 does not need to overlap the outer peripheral surface of the end portion of the rotating shaft 26. It is sufficient that at least a part of the inner peripheral surface of the hollow portion 55 overlaps at least a part of the outer peripheral surface of the end portion of the rotary shaft 26 at the maximum valve opening position of the valve body 44.

  3A and 3B are diagrams illustrating an example of the operation of the valve body 44. FIG. FIG. 3A shows a state when the pump is operating, and FIG. 3B shows a state when the pump is stopped.

  During the pump operation, the valve body 44 is in the maximum valve opening position. At this time, as shown in FIG. 3A, the protruding portion 51 of the valve body 44 overlaps the outer peripheral surface of the end portion of the rotating shaft 26. Therefore, a large space like the region A shown in FIG. 8A is not formed in front of the valve body 44. Therefore, it is possible to prevent the occurrence of various flow losses such as separation of water flow and generation of vortices due to rapid expansion of the flow path.

  In addition, when the pump is stopped, the valve body 44 is lowered to the valve closing position. Therefore, as shown in FIG. 3B, the protruding portion 51 of the valve body 44 is positioned close to the bearing 28 (preferably, the tip of the protruding portion 51. And the bearing 28 can be overlaid on the outer peripheral surface of the end of the rotating shaft 26 at a position where the distance between the rotating shaft 26 and the bearing 28 is 0.1 mm to 10 mm, more preferably 0.1 mm to 2 mm (in this case, The axial length of the end is preferably substantially equal to the moving distance of the valve body 44 from the maximum valve opening position to the valve closing position), so that the space between the end of the rotating shaft 26 and the bearing 28 It is possible to reduce the possibility of foreign matter entering the battery. Therefore, damage to the bearing 28 due to foreign matter can be prevented. In addition, since the rotation of the rotary shaft 26 is not hindered by foreign matter, it is possible to prevent the pump efficiency from being lowered.

  4 to 6 show second to fourth embodiments of the present invention. In 2nd-4th embodiment, only a different part from said 1st embodiment is demonstrated, and detailed description is abbreviate | omitted about another part.

  In the second embodiment shown in FIG. 4, the point that the valve body 74 includes a protruding portion 76 that protrudes from the approximate center of the annular portion 75 toward the end of the rotating shaft 100 is the same as the valve body 44 of FIG. Although it is the same, the point which the protrusion part 76 does not have a hollow part (namely, it is solid) differs from the valve body 44. FIG. In the example of FIG. 4, the end of the rotating shaft 100 includes a recess 77 that opens toward the protrusion 76 and has an inner diameter larger than the outer diameter of the protrusion 76. In the second embodiment, the protruding portion 76 of the valve body 74 is configured to overlap the inner peripheral surface of the recess 77.

  FIG. 4 shows a state in which the valve element 74 is in the maximum valve opening position during the pump operation. Therefore, as in the first embodiment, the presence of the protrusion 76 prevents a large space such as the region A shown in FIG. 8A from being formed in front of the valve body 74. Therefore, it is possible to prevent the occurrence of various flow losses such as separation of water flow and generation of vortices due to rapid expansion of the flow path.

  In the third embodiment shown in FIG. 5, the valve body 84 includes a solid protrusion 86 that protrudes from the approximate center of the annular portion 85 toward the end of the rotating shaft 101. Similar to the body 74. Also, the end of the rotating shaft 101 is provided with a recess 87 that opens toward the projecting portion 86 and has an inner diameter larger than the outer diameter of the projecting portion 86, as in FIG. However, in this example, the end portion of the rotating shaft 101 includes an enlarged portion 88 that is enlarged outward in the radial direction (left-right direction in the drawing), and a concave portion 87 is formed in the enlarged portion 88. Thus, the protruding portion 86 of the valve body 84 is configured to overlap the inner peripheral surface of the recess 87.

FIG. 5 shows a state in which the valve body 84 is in the maximum valve opening position during the pump operation. Therefore, as in the above embodiment, the presence of the protruding portion 86 does not form a large space like the region A shown in FIG. 8A in front of the valve body 84. Therefore, it is possible to prevent the occurrence of various flow losses such as separation of water flow and generation of vortices due to rapid expansion of the flow path.

  Further, in the third embodiment, when the pump is stopped, the enlarged portion 88 at the end of the rotating shaft 101 can prevent foreign matter from entering between the end of the rotating shaft 101 and the bearing 28. Therefore, there is no risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

  In the fourth embodiment shown in FIG. 6, the valve body 94 includes a solid protrusion 96 that protrudes from the approximate center of the annular portion 95 toward the end of the rotating shaft 102. This is the same as the valve bodies 74 and 84 of No. 5. However, unlike the example of FIGS. 4 and 5, the projecting portion 96 has a recess 97 defined by the inner peripheral surface of the annular member 98 attached to the end of the rotating shaft 102 and the end surface of the rotating shaft 102. It is comprised so that it may overlap with an internal peripheral surface.

  FIG. 6 shows a state in which the valve element 94 is in the maximum valve open position during the pump operation. Therefore, as in the above-described embodiment, the presence of the protrusion 96 prevents a large space such as the region A shown in FIG. 8A from being formed in front of the valve element 94. Therefore, it is possible to prevent the occurrence of various flow losses such as separation of water flow and generation of vortices due to rapid expansion of the flow path.

  Furthermore, in the fourth embodiment, when the pump is stopped, the annular member 98 can prevent foreign matter from entering between the end of the rotating shaft 102 and the bearing 28. Therefore, there is no risk of bearing damage and / or a decrease in pump efficiency due to foreign matter intrusion.

  The present invention can be widely applied to a pump including an elevating check valve.

A ... Area B ... Area 11 ... Discharge casing 12 ... Valve seat 13 ... Valve rod 14 ... Valve 16 ... Discharge port 21 ... Submersible motor 22 ... Suction port 23 ... Impeller 24 ... Intermediate casing 26 ... Rotary shaft 27 ... Guide vane 43 ... Valve rod 44 ... Valve body 50 ... Annular part 51 ... Projection part 55 ... Hollow part 56 ... Hollow part 74 ... Valve body 75 ... Annular part 76 ... Projection part 77 ... Recess 84 Projection 87: Recess 88 ... Enlarged part 94 ... Valve element 95 ... Ring part 96 ... Projection 97: Recess 98 ... Ring member 100 ... Rotating shaft 101 ... Rotating shaft 102 ... Rotating shaft

Claims (7)

A pump casing having a suction port and a discharge port;
A rotating shaft disposed in the pump casing;
A plurality of impellers fixed to the rotating shaft and arranged in multiple stages, and a pump comprising:
The pump casing includes a discharge casing having the discharge port,
The pump further comprises:
Comprising a check valve configured to prevent back flow of the fluid sent into the discharge casing through the plurality of impellers;
The check valve includes a valve seat, and a valve body that can be raised and lowered between a maximum valve opening position that is maximally spaced from the valve seat and a valve closing position that is seated on the valve seat,
The valve body includes a protruding portion that protrudes toward the end of the rotating shaft,
The pump is configured to overlap the peripheral surface of the end of the rotating shaft at the maximum valve opening position.   The protruding portion includes a hollow portion that opens toward an end portion of the rotating shaft and has an inner diameter larger than an outer diameter of the end portion of the rotating shaft, and the hollow portion is an end portion of the rotating shaft. The pump according to claim 1, wherein the pump is configured to overlap with an outer peripheral surface of the pump.   The end of the rotating shaft includes a recess that opens toward the protrusion and has an inner diameter that is larger than the outer diameter of the protrusion, and the protrusion overlaps the inner peripheral surface of the recess. The pump according to claim 1, which is configured as follows.   4. The pump according to claim 3, wherein an end of the rotating shaft includes an enlarged portion that is enlarged radially outward, and the recessed portion is formed in the enlarged portion.   An annular member is attached to an end of the rotating shaft, and the protruding portion is configured to overlap an inner peripheral surface of a recess defined by an inner peripheral surface of the annular member and an end surface of the rotating shaft. The pump according to claim 1.   The pump as described in any one of Claims 1-5 provided with the valve rod which is fixed to the said valve body and supports the said valve body so that raising / lowering is possible.   The pump according to any one of claims 1 to 6, further comprising a motor coupled to the rotating shaft.

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