JP2014015937A6 - Pumping system - Google Patents

Abstract

The present invention provides a pumping system that can be easily maintained and inspected and that can shorten the pumping start time.
A pumping system includes a liquid storage tank that stores a liquid, a pump, a liquid suction pipe, a discharge pipe, and a valve. The liquid absorption pipe 50 connects the liquid storage tank 10 and the pump 20, the discharge pipe 60 circulates the liquid discharged from the pump 20, the pump 20 is installed on the ground, and the liquid absorption pipe 50 and the discharge pipe 60. Pump the liquid through. In the valve 100, the primary side UP communicates with the inside of the liquid storage tank 10, and the secondary side DW communicates with the pump 20, so that the liquid suction pipe 50 is cut open. The valve 100 is provided on the ground portion 53 of the liquid suction pipe 50. The primary side UP of the liquid suction pipe 50 is filled with liquid and has a negative pressure.
[Selection] Figure 1

Description

  The present invention relates to a pumping system for pumping liquid stored in a liquid storage tank.

  With regard to this type of technology, Patent Document 1 describes a fire extinguishing pump system including a foot valve provided at the lower end of a water absorption pipe and an expiratory tank installed above the pump to supply expiratory water to the pump. ing. Patent Document 2 describes the structure of a foot valve. The foot valve is a check valve in which a strainer for removing foreign substances is provided on the suction side, and a valve seat and a swinging valve body are installed inside the valve box. The valve body swings unilaterally only on the discharge side with respect to the valve seat, and the valve opens. A lever and a wire rope are connected to the valve body, and when the foot valve is maintained and inspected, the valve can be forcibly opened and dropped by pulling the wire rope from the ground.

  Patent Document 3 describes a pumping system in which a pump is installed on the ship of a small ship to pump seawater into the ship. The water intake pipe is provided with an open / close valve such as a ball valve (globe valve) and an intake pump. Seawater is pumped into the water intake pipe using an intake pump, and the water is filled into the water intake pipe at a positive pressure exceeding the atmospheric pressure to serve as the priming water for the pump. Patent Document 3 describes that a foot valve is optionally provided at the end of the water absorption pipe.

JP 2009-6158 A Japanese Patent Laid-Open No. 11-166644 JP 2004-278470 A

  Since the foot valve of patent document 1 and patent document 2 is immersed in the water storage tank, there exists a possibility that rust may generate | occur | produce and the opening / closing operation | movement of a valve may be impaired. If the opening / closing operation of the valve becomes poor, water will fall from the water suction pipe while the pump is stopped, and thus seizure will occur during the operation of the pump, causing a problem. For this reason, the foot valve requires regular maintenance and inspection work. However, since the depth of the water tank reaches several meters depending on the pumping system, the maintenance and inspection work of the foot valve is not easy. It is extremely difficult to raise the foot valve together with the water absorption pipe to the ground because it involves disassembling the piping, and it is also difficult for humans to work while diving the inside of the water tank to the foot valve. Also, the foot valve body immersed in the water tank is loaded with the mass of water remaining in the piping on the ground, so it is difficult to forcibly open the valve body by operating the foot valve lever. Accompanied by.

  On the other hand, in the offshore pumping system of Patent Document 3, in order to draw positive water with an intake pump with respect to the water absorption pipe, when a foot valve is provided at the end of the water absorption pipe, Patent Document 1 and Patent Document 2 Similar problems arise. When the foot valve is not provided at the end of the water absorption pipe, when the pump is stopped, the inside of the water absorption pipe changes from a state where water is primed to a positive pressure. For this reason, it is difficult to quickly restart the pump.

  This invention is made | formed in view of the above subjects, and provides the pumping system which can perform maintenance and inspection work easily, and can shorten pumping start time.

  According to the present invention, a liquid storage tank that stores liquid, a pump that is installed on the ground and pumps the liquid, a liquid suction pipe that connects the liquid storage tank and the pump, and a pump that is discharged from the pump. A discharge pipe through which the liquid flows, and a valve whose primary side communicates with the interior of the liquid storage tank and whose secondary side communicates with the pump and which shuts off the liquid absorption pipe so as to be openable. The primary side of the liquid suction pipe and the primary side of the liquid suction pipe and the primary side of the liquid suction pipe are in a state where the primary side of the liquid suction pipe is filled with the liquid and has a negative pressure and the pump is stopped. The secondary side is filled with the liquid, and the primary side is a negative pressure having a larger absolute value than the secondary side, and the ground portion of the suction pipe from the valve to the pump rises toward the pump. Pumping water characterized by being inclined Temu is provided.

  In the present invention, the valve may be a check valve that unidirectionally circulates the liquid from the primary side to the secondary side.

In the present invention, the check valve includes a valve seat having an opening through which the liquid flows, and a valve that linearly reciprocates in a direction toward or away from the opening so as to open and close the opening. And an elastic body that biases the valve body toward the valve seat, and the discharge pipe unilaterally distributes the liquid discharged from the pump in the discharge direction. A valve is provided and when the pumping operation of the pump is stopped, the valve body of the check valve is after the second check valve is closed and the second check valve is closed. The opening may be closed before the back flow of the liquid generated by the above process reaches the check valve via the pump.
The second check valve includes a valve seat having an opening for circulating the liquid, a valve body that linearly reciprocates in the contact and separation direction with respect to the opening, and closes the opening so as to be openable and closable. An elastic body that urges the body toward the valve seat, and the valve body of the second check valve closes the opening, and the valve body of the check valve opens the opening. It may be larger than the pressing force for closing.
In the check valve and the second check valve, packings that seal the opening in a liquid-tight manner are interposed between the valve seat and the valve body, respectively, and the check valve The packing may be made of a softer material than the packing of the second check valve.
The check valve includes an opening-side guide for guiding the reciprocation of the valve body, and the opening-side guide is provided on one of the valve seat or the valve body and the other of the valve seat or the valve body. And the radial clearance between the opening side guide and the other increases gradually from the state in which the valve body closes the opening, as the valve body moves away from the opening. It may be configured as follows.
The opening-side guide may have a tapered shape with a width dimension that decreases toward the tip side in the protruding direction.
The flow path volume (V1) from the valve seat of the check valve to the pump may be larger than the flow path volume (V2) from the valve seat of the check valve to the liquid storage tank.
The check valve may include a valve box that houses the valve body, and the valve box may be formed with an opening on the primary side of the valve body.
The pump may be an inverter pump, and a vacuum pump may be connected to the pressure reducing port.
The lower end part of the said liquid absorption pipe located inside the said liquid storage tank may open upwards.
The lower end portion of the liquid absorption pipe includes a pipe end of the liquid absorption pipe and a water retention portion that is integrally connected to the pipe end and accommodates the pipe end, and the pipe end opens downward and the water retention capacity. The lower end portion of the liquid suction pipe may be opened upward by opening the portion upward.
A flange portion may be formed on an end surface on the secondary side of the valve, and a normal direction of the flange portion may be inclined obliquely upward.
The check valve is an angle valve in which a reciprocating direction of the valve body and an axial flow direction intersect, and the valve body can be taken out from a valve box that houses the valve body. Good.
The check valve is a straight valve in which the reciprocating direction of the valve body and the axial flow direction are parallel, and the check valve is inclined so that the position on the secondary side is higher than the primary side. You may further provide the installation stand hold | maintained.

  According to the pumping system of the present invention, since the valve is provided on the ground portion of the liquid suction pipe of the pump, its maintenance and inspection work is easy. Further, since the primary side of the liquid suction pipe is filled with liquid and has a negative pressure, the pressure reduction range until the pump is activated can be reduced. For this reason, the pumping start time of the pump can be shortened, contributing to energy saving, and reducing the load on the entire pumping system and improving its durability.

  The above-described object and other objects, features, and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings.

It is a figure showing the whole pumping system composition of a first embodiment of the present invention. Fig.2 (a) is a longitudinal cross-sectional view which shows the closed state of the non-return valve of 1st embodiment. FIG.2 (b) is a longitudinal cross-sectional view which shows the open state of the non-return valve of 1st embodiment. It is a longitudinal cross-sectional view of a 2nd check valve. Fig.4 (a) is a longitudinal cross-sectional view which shows the closed state of the non-return valve of 2nd embodiment. FIG.4 (b) is a longitudinal cross-sectional view which shows the open state of the non-return valve of 2nd embodiment. Fig.5 (a) is a longitudinal cross-sectional view which shows the closed state of the non-return valve of 3rd embodiment. FIG.5 (b) is a longitudinal cross-sectional view which shows the open state of the non-return valve of 3rd embodiment. It is a figure which shows the whole structure of the pumping system of 4th embodiment. Fig.7 (a) is a cross-sectional schematic diagram which shows the 1st example of the lower end part of a liquid absorption pipe | tube. FIG. 7B is a schematic cross-sectional view showing a second example of the lower end portion of the liquid absorption pipe. It is a figure which shows the whole structure of the pumping system of 5th embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate. Various components such as the check valve and piping of the pumping system of the present invention do not have to be individually independent, but a plurality of components are formed as one member, and one component is Allowed to be formed of multiple members, a certain component is a part of another component, a part of a certain component overlaps a part of another component, etc. To do.

<First embodiment>
First, the outline | summary of the pumping system 1000 of this embodiment is demonstrated.
A pumping system 1000 according to the first embodiment shown in FIG. 1 includes a liquid storage tank 10 that stores a liquid L, a pump 20, a liquid suction pipe 50, a discharge pipe 60, and a valve 100.
The liquid absorption pipe 50 is a pipe connecting the liquid storage tank 10 and the pump 20. The discharge pipe 60 is a pipe through which the liquid L discharged from the pump 20 flows. The pump 20 is installed on the ground and pumps the liquid L through the liquid suction pipe 50 and the discharge pipe 60.
In the valve 100, the primary side UP communicates with the inside of the liquid storage tank 10, and the secondary side DW communicates with the pump 20, so that the liquid suction pipe 50 is cut open. The valve 100 is provided on the ground portion 53 of the liquid suction pipe 50. The primary side UP of the liquid suction pipe 50 is filled with the liquid L and has a negative pressure.

  Here, the primary side UP of the liquid suction pipe 50 is filled with the liquid L. The valve body 120 of the valve 100 from the lower end of the liquid suction pipe 50 (see FIGS. 2A and 2B). The flow path up to is substantially filled with the liquid L. The primary side UP of the liquid suction pipe 50 is a negative pressure. The static pressure of the liquid L in the flow path from the lower end of the liquid suction pipe 50 to the valve body 120 of the valve 100 when the pump 20 is operated and stopped. It means lower than the atmospheric pressure (atmospheric pressure).

  In Patent Document 1 and Patent Document 2 described above, the mass of water in the piping on the ground is loaded on the foot valve when the pump is stopped, and positive pressure is applied to the water in the liquid suction pipe. In the pumping system of Patent Document 3, since the inside of the liquid suction pipe is called positive pressure, when the liquid suction pipe is filled with water, a positive pressure is applied to the water on the primary side of the liquid suction pipe. Yes. On the other hand, in the pumping system 1000 of the present embodiment, the liquid L on the primary side UP of the liquid suction pipe 50 has a negative pressure not only during the operation of the pump 20 but also when the pump 20 is stopped. For this reason, the pressure reduction range until the operation of the pump 20 is reduced, and the pumping system 1000 can be operated with low load and energy saving.

  Here, the primary side UP of the valve 100 communicating with the inside of the liquid storage tank 10 means that the lower end of the liquid suction pipe 50 is inside the liquid storage tank 10. When a sufficient amount of the liquid L is stored in the liquid storage tank 10, the lower end of the liquid suction pipe 50 is immersed in the liquid L, and the liquid suction pipe 50 has an underwater portion 51 lower than the liquid level FL. It becomes. Although a check valve (foot valve) having a water stop function is not provided at the lower end of the underwater portion 51 of the present embodiment, a foot valve (underwater foot valve) may optionally be provided at the lower end of the underwater portion 51. Good. In addition, a strainer (not shown) for removing a foreign substance that does not have a water stop function may be provided at the lower end of the underwater portion 51. The valve 100 may be formed by connecting a plurality of stages of valves in series or in parallel. In this case, at least one valve is provided above the liquid level FL.

  Next, the pumping system 1000 of this embodiment will be described in detail. The pumping system 1000 is used for various purposes such as water supply and sewage supply, water supply for fire extinguishing and ballast, and coolant supply. The liquid L can be selected according to the use other than water.

  A driving unit 22 such as a motor is connected to the pump 20. The pump 20 is a land pump and may be self-priming or non-self-priming. In this embodiment, a non-self-priming centrifugal pump is illustrated. The expiratory water tank 24 is installed higher than the pump 20. Expiration water is supplied to the pump 20 by opening the on-off valve 26.

  The liquid absorption pipe 50 roughly includes an underwater portion 51, a water surface portion 52, and a ground portion 53. The underwater portion 51 is a length region immersed below the liquid level FL of the liquid L. The water portion 52 is a length region from the liquid level FL of the liquid L to the primary side UP of the valve 100. When the valve 100 is installed in the vicinity of the liquid level FL, the length of the water portion 52 is substantially zero. The ground portion 53 is a length region from the secondary side DW of the valve 100 to the suction side SS of the pump 20. The ground portion 53 includes an area existing above, on the surface and in the ground, and an area existing on the secondary side DW of the valve 100 and above the liquid level FL of the liquid storage tank 10. Including. Here, the valve 100 is provided on the ground portion 53, that at least a part of the valve 100 is above the liquid level FL, and the valve 100 is located at an end portion or an intermediate portion of the ground portion 53 of the liquid suction pipe 50. It means being connected.

  In the pumping system 1000 of the present embodiment, with the pump 20 stopped, the primary side UP and the secondary side DW of the liquid suction pipe 50 are filled with the liquid L, and both the primary side UP and the secondary side DW are both Negative pressure. The primary side UP is a negative pressure having a larger absolute value than the secondary side DW.

  When the pump 20 is operated with priming water in the suction pipe 50, the pump 20 sucks the liquid L inside the suction pipe 50, and the primary side UP and the secondary side DW of the suction pipe 50 are negative pressure. Become. When the pump 20 reaches a predetermined operating pressure (negative pressure), the liquid L is sucked up from the liquid storage tank 10 and supplied to a desired application through the discharge pipe 60. From this state, the valve 100 is closed at substantially the same time as the pump 20 is stopped to prevent the liquid absorption pipe 50 from falling. In this state, the static pressure of the liquid L existing in the water portion 52 and the ground portion 53 of the liquid suction pipe 50 is a negative pressure.

  The valve 100 of the present embodiment is a check valve that unidirectionally circulates the liquid L from the primary side UP to the secondary side DW of the liquid suction pipe 50. For this reason, negative pressure is maintained in the water surface portion 52 and the ground surface portion 53 without falling from the water surface portion 52 of the liquid suction pipe 50.

  With the valve 100 closed, the suction side SS of the stopped pump 20 leaks and approaches the atmospheric pressure (atmospheric pressure). On the other hand, in the water portion 52 corresponding to the primary side UP of the closed valve 100, the negative pressure when the pump 20 is stopped is maintained. Therefore, as described above, in the state where the pump 20 is stopped, the primary side UP of the liquid suction pipe 50 becomes a negative pressure having a larger absolute value than the secondary side DW. When the pump 20 is restarted from this state, the pump 20 sucks the liquid L in the ground portion 53, and when it reaches the predetermined operating pressure (negative pressure), the liquid L flows again in the flow direction F.

  In the present embodiment, a so-called angle valve check valve is disposed as the valve 100 at a portion where the water surface portion 52 extending in the vertical direction and the ground portion 53 extending in the substantially horizontal direction intersect. To do. That is, the valve 100 (check valve) of the present embodiment is an angle valve in which the reciprocating direction of the valve body 120 (vertical direction in each drawing of FIG. 2) and the axial flow direction AF intersect. The axial flow direction AF is an average of the flow direction F of the liquid L from the primary side UP to the secondary side DW. Specifically, as shown in FIG. 2B, the curve direction is a direction in which the primary side UP and the secondary side DW are connected substantially orthogonally with the valve body 120 interposed therebetween. 2A and 2B are cross sections (longitudinal cross sections) of the valve 100 cut along the axial flow direction AF.

  The extending direction of the discharge pipe 60 (see FIG. 1) is arbitrary. In the present embodiment, a mode in which the discharge pipe 60 extends vertically upward is illustrated. As shown in the longitudinal sectional view of FIG. 3, the second check valve 200 has a primary UP on the lower side and a secondary DW on the upper side, and the operating direction and axial flow direction of the valve body 220 reciprocating in the vertical direction. Is a straight valve that matches.

  In the liquid suction pipe 50 connected to the suction side SS of the pump 20, a check valve (hereinafter sometimes referred to as the first check valve 100) is disposed as a valve 100 in the flow path of the liquid L. The discharge pipe 60 connected to the discharge side DS of the pump 20 is provided with a second check valve 200 that unidirectionally distributes the liquid L discharged from the pump 20 in the discharge direction. An on-off valve 280 is installed on the further secondary side (the upper side in FIG. 1) of the second check valve 200.

  The first check valve 100 and the second check valve 200 of the present embodiment are both lift type check valves that incorporate an elastic body.

  As shown in FIGS. 2A and 2B, the first check valve 100 includes a valve seat 110 having an opening 112 through which the liquid L flows and a straight line in a direction approaching or separating from the opening 112. A valve body 120 that reciprocally moves to close the opening 112 so as to be freely opened and closed, and an elastic body 130 that urges the valve body 120 toward the valve seat 110.

  An outlet 132 is formed on the secondary side DW of the first check valve 100 so as to be substantially orthogonal to the inlet 116 of the primary UP. The valve seat 110, the valve body 120 and the elastic body 130 are accommodated in the valve box 160. The valve body 120 is integrally provided at the lower end of the guide shaft 122, that is, at the proximal end of the guide shaft 122 viewed from the opening 112. A support portion 124 is detachably provided inside the valve box 160. The support portion 124 holds the guide shaft 122 so as to be slidable. The sliding direction of the guide shaft 122 is the normal direction of the inlet 116 and the opening 112.

  An elastic body 130 is attached around the guide shaft 122. The elastic body 130 of this embodiment is a spiral spring. The elastic body 130 is provided between the valve body 120 and the support portion 124. In a state where the valve body 120 is in contact with the valve seat 110 and the opening 112 is closed in a watertight manner (closed state), the elastic body 130 is compressed more than the natural length, and the valve body 120 is biased toward the valve seat 110. doing. The urging force of the elastic body 130 in the closed state is larger than the total weight of the valve body 120 and the guide shaft 122. The difference between the biasing force of the elastic body 130 and the total weight of the valve body 120 and the guide shaft 122 is referred to as the closing force of the valve 100. Here, since the primary side UP of the liquid suction pipe 50 has a negative pressure stronger than the secondary side DW when the pump 20 is stopped, the valve body 120 maintains the closed state even if the closing force of the valve 100 is small. be able to. Thereby, regardless of the relationship between the installation direction of the first check valve 100 and the direction of gravity, the valve body 120 can stop the water of the secondary side DW in the closed state. For convenience, in the present embodiment, the primary side UP is illustrated below each of FIGS. 1 and 2, but the vertical direction and the gravity direction in the drawings do not necessarily coincide with each other.

  In the first check valve 100, a packing 140 that seals the opening 112 in a liquid-tight manner is interposed between the valve seat 110 and the valve body 120. For the packing 140, an O-ring made of a soft resin material such as rubber can be used.

  An opening / closing lid 162 detachable from the valve box 160 is provided at a corner portion of the valve box 160 in the first check valve 100 which is an angle valve. The opening / closing lid 162 is provided on the side away from the opening 112 in the extending direction of the guide shaft 122, specifically, in the axial direction of the guide shaft 122. A ring-shaped holder 164 is fixed to the inner surface side of the opening / closing lid 162. The holder 164 slidably holds the upper end portion of the guide shaft 122, in other words, the distal end portion of the guide shaft 122 viewed from the opening 112.

  The first check valve 100 includes an opening side guide 150 that guides the reciprocating motion of the valve body 120. The opening side guide 150 is provided on one of the valve seat 110 and the valve body 120 (the valve body 120 in the present embodiment), and protrudes toward the other (the valve seat 110). The opening side guide 150 includes a plurality of protruding claw portions 152. The plurality of protrusions 152 are arranged on the ring so as to be separated from each other along the outer peripheral edge of the valve body 120.

  The circumferential surface that envelops the main surface 153 on the outer side of the plurality of protrusions 152 is slightly smaller than the circumferential wall 114 of the opening 112. The radial clearance between the opening side guide 150 in the first check valve 100 and the valve seat 110 or the other of the valve bodies 120 (the valve seat 110) is a state in which the valve body 120 closes the opening 112 (see FIG. 2 (see (a)), the valve body 120 is configured to gradually increase as the distance from the opening 112 increases. Specifically, the thickness of the projecting claw portion 152 constituting the opening side guide 150, that is, the radial dimension of the opening 112 gradually decreases toward the protruding tip side. Increasing gradually means increasing in multiple steps or continuously.

  In a state where the valve body 120 is close to or in contact with the valve seat 110, the protruding claw portion 152 is inserted into the opening 112 and contacts the peripheral wall 114. For this reason, the valve body 120 and the guide shaft 122 are supported at two points by the opening side guide 150 (protruding claw portion 152) and the support portion 124 at least in a closed state or a state close thereto. Here, the two-point support means a state in which the valve body 120 and the guide shaft 122 are held at two places or three or more places having different reciprocating directions.

When the valve body 120 is pushed up from the valve seat 110 as indicated by an arrow in FIG. 2A, the elastic body 130 is compressed. FIG. 2B shows a maximum open state in which the elastic body 130 is compressed to the elastic compression limit and the valve body 120 reaches the top dead center. The displacement amount (maximum stroke) of the valve body 120 from the closed state to the maximum open state is larger than the protruding length of the protruding claw portion 152. That is, when the valve body 120 is located at or near the top dead center, the tip of the projecting claw portion 152 is spaced above the valve seat 110. At this time, the upper end portion of the guide shaft 122 is inserted through the holder 164. Therefore, the valve body 120 and the guide shaft 122 are always supported at two points by the support portion 124 and at least one of the protruding claw portion 152 or the holder 164 regardless of the position of the valve body 120.
When the flow rate of the liquid L increases and the valve body 120 is sufficiently opened to the vicinity of the top dead center, the protruding claw portion 152 is separated from the opening 112, thereby suppressing the protruding claw portion 152 from obstructing the flow of the liquid L. Has been. On the other hand, when the valve body 120 is in the closed state or in the vicinity thereof, the protruding claw portion 152 is guided by the peripheral wall 114 and the valve body 120 faces the opening 112. For this reason, the packing 140 is securely attached to the valve seat 110 in the closed state.

  At this time, the clearance between the projecting claw portion 152 and the peripheral wall 114 gradually increases as the valve body 120 moves away from the opening 112 as described above. Specifically, there is a radial clearance between the protruding claw portion 152 and the peripheral wall 114 in the open state of the valve 100, and the outer main surface 153 of the protruding claw portion 152 and the peripheral wall 114 are in contact in the closed state. Clearance is zero. Thereby, when the valve body 120 is closed from the maximum open state, the projecting claw portion 152 does not interfere with the valve seat 110. Immediately before the valve body 120 comes into contact with the valve seat 110, the projecting claw portion 152 slides against the peripheral wall 114, so the reproducibility of the relative position between the valve body 120 and the valve seat 110 in the closed state is good.

  The opening side guide 150 of the present embodiment has a tapered shape in which the width dimension decreases toward the distal end side in the protruding direction. The wall thickness of each protruding claw portion 152 of the opening side guide 150 decreases toward the primary side UP. When the valve body 120 is gradually closed from the maximum open state, the amount of decrease in the opening area of the opening 112 is slight when the tip of the protruding claw portion 152 slightly enters the inside of the opening 112. As the valve body 120 approaches the closed state, the cross-sectional area of the projecting claw portion 152 entering the inside of the opening 112 gradually increases, and the opening 112 is gradually closed. For this reason, the flow of the liquid L which flows into the valve box 160 from the primary side UP and bypasses the valve body 120 is gradually throttled. Therefore, the water hammer (back flow) generated at the moment when the valve body 120 reaches the closed state is reduced.

  In this embodiment, although the case where the intermediate part of the guide shaft 122 was supported by the support part 124 was illustrated, this invention is not limited to this. Without providing the support portion 124, the upper end of the guide shaft 122 may be supported by the holder 164, and the projecting claw portion 152 may be supported by the peripheral wall 114. In this case, it is preferable that the projecting claw 152 is supported by the peripheral wall 114 in a state where the valve 100 is fully opened. The guide shaft 122 may be supported by the holder 164 when the valve 100 is closed. As a result, the projecting claw 152 is always supported by the peripheral wall 114 from the closed state of the valve 100 to the maximum open state. Specifically, it is preferable that the protruding length of the protruding claw portion 152 is larger than the maximum stroke of the valve body 120. Furthermore, it is preferable that the upper end of the guide shaft 122 is inserted into the holder 164 when the valve 100 is closed.

  As shown in FIG. 3, a similar opening side guide (protruding claw portion 252) is also formed on the second check valve 200 so as to protrude from the primary side UP of the valve body 220. For this reason, the backflow generated at the moment when the valve body 220 reaches the closed state is also reduced with respect to the second check valve 200.

  The valve box 160 is formed with a bypass passage 169 that communicates the secondary side DW of the closed valve body 120 and the primary side UP. The bypass 169 is closed by a water drop valve 168 so that it can be opened and closed. When the secondary side DW of the first check valve 100 in the closed state is filled with water and the valve body 120 stops the water, the water falling valve 168 is opened so that the water passes through the bypass 169 to the primary side. Fall into UP.

  The first check valve 100 of the present embodiment is configured such that the valve body 120 can be taken out from the valve box 160 that houses the valve body 120. Specifically, the support portion 124 and the opening / closing lid 162 can be removed from the valve box 160, and the guide shaft 122, the elastic body 130, and the valve body 120 can be removed from the valve box 160 with these removed. . Specifically, the open / close lid 162 and the support portion 124 are removed from the valve box 160 in a state where the water check valve 168 is operated to drain the first check valve 100. Next, by removing the guide shaft 122 and the valve body 120 from the valve box 160, maintenance and inspection work such as cleaning and replacement of the elastic body 130 and the packing 140 can be performed.

  As shown in FIG. 3, the second check valve 200 is also opened by reciprocating linearly in the contact / separation direction with respect to the valve seat 210 including the opening 212 on the inflow side through which the liquid L flows. The valve body 220 which closes 212 so that opening and closing is possible, and the elastic body 230 which urges | biases the valve body 220 toward the valve seat 210 are provided. FIG. 3 shows an open state in which the valve body 220 is separated from the valve seat 210.

  The primary UP inlet 216 of the second check valve 200 and the secondary DW outlet 232 are opposed to each other. The valve seat 210, the valve body 220, and the elastic body 230 are accommodated inside the valve box 260. A support portion 224 is provided inside the valve box 260 in the same manner as the first check valve 100. The support portion 224 holds the guide shaft 222 so as to be slidable. The sliding direction of the guide shaft 222 is the contact / separation direction with respect to the opening 212. The valve box 260 is provided with a water drop valve 270, and water can be drained by communicating the secondary side DW and the primary side UP of the valve body 220 in the second check valve 200 in the closed state.

  Also in the second check valve 200, a packing 240 that seals the opening 212 in a liquid-tight manner is interposed between the valve seat 210 and the valve body 220. For the packing 240, an O-ring made of a soft resin material such as rubber can be used. The packing 140 of the first check valve 100 in the present embodiment is made of a softer material than the packing 240 of the second check valve 200. The hardness of the packings 140 and 240 can be compared based on the magnitude of the durometer A hardness measured according to JIS K6253.

  Returning to FIG. 1, the on-off valve 280 is opened, the on-off valve 26 is opened, and the pump 20 is operated after supplying exhalation water from the exhalation tank 24 to the pump 20 and the ground portion 53.

  As shown in FIG. 1, the vertical distance between the valve seat 210 (see FIG. 3) of the second check valve 200 and the discharge side DS of the pump 20 is H1. The vertical distance between the suction side SS of the pump 20 and the valve seat 110 of the first check valve 100 (see each drawing in FIG. 2) is H2. The vertical distance between the valve seat 110 of the first check valve 100 and the liquid level FL is H3. The vertical distance from the liquid level FL to the lower end of the underwater portion 51 is H4.

  The ground portion 53 of the liquid suction pipe 50 from the valve 100 to the pump 20 is inclined upward toward the pump 20. The slope φ of the ground portion 53 is 1% or more, preferably 3% or more. The gradient φ is preferably 10% or less. Here, the fact that the ground portion 53 is inclined means that, in at least a partial region of the ground portion 53, the central axis thereof obliquely intersects the horizontal plane. The vertical distances H2 and H3 may be set based on the pipe length of the ground portion 53 of the liquid suction pipe 50 and the gradient φ. The vertical distance H4 below the liquid level FL is not particularly limited, but is 1 m or more, preferably 2 m or more.

  In the pumping system 1000 of this embodiment, the vertical distance H2 is smaller than the vertical distance H4. For this reason, when the pump 20 is stopped, the gravity acting on the liquid L existing in the ground portion 53 of the liquid suction pipe 50 is smaller than the liquid L existing in the water surface portion 52.

  Since the ground portion 53 is inclined upward toward the pump 20, even if bubbles are mixed in the ground portion 53, it does not stay in the valve box 160 of the valve 100. Here, if bubbles exist in the liquid suction pipe 50 connected to the suction side SS of the pump 20, a part of the pump performance is lost because the discharge pressure of the pump 20 disappears as the expansion pressure of the bubbles. In the pumping system 1000 of the present embodiment, since the bubbles inside the liquid suction pipe 50 are sent from the valve 100 to the pump 20 and discharged outside the system, there is no possibility of this.

  As shown in each drawing of FIG. 2, a flange portion 170 is formed on the end surface of the secondary side DW of the valve 100. The normal direction of the flange portion 170 is inclined obliquely upward. The normal direction of the flange portion 170 is inclined obliquely upward means that the normal line of the end surface of the flange portion 170 formed around the outflow port 132 in the installed state of the valve 100 is vertical as well as a horizontal component. It means that it contains an upward component. The valve 100 of this embodiment is an angle valve, and the valve 100 is installed in the pumping system 1000 so that the inlet 116 faces downward. Therefore, the axial direction (outward) of the inflow port 116 and the normal direction (outward) of the flange portion 170 form an obtuse angle.

  The flange portion 170 includes a secondary flange 166 of the valve box 160 and a spacer 172. The spacer 172 is detachably fixed to the valve box 160. Specifically, the secondary side flange 166 has an annular shape. The spacer 172 has a plate shape, and the main surfaces of the front and back surfaces are non-parallel and are inclined with each other at a predetermined angle. This inclination angle θ is equal to the gradient φ of the ground portion 53 of the liquid suction pipe 50. The main surface of the spacer 172 has an annular shape that is the same shape as the secondary flange 166. Bolt holes (not shown) are formed in the spacers 172 and the secondary side flange 166 at the same number and the same position. The ground portion 53 of the liquid suction pipe 50 and the secondary flange 166 are bolted together with the spacer 172 interposed therebetween. Accordingly, even when a general straight pipe with a flange, that is, a pipe in which the axis of the straight pipe is perpendicular to the flange, is used as the ground portion 53 (see FIG. 1) of the liquid suction pipe 50, The ground portion 53 can be inclined upward toward the pump 20 with a gradient φ simply by being connected to the flange portion 170.

A flow path volume V1 from the valve seat 110 of the valve 100 to the pump 20 is larger than a flow path volume V2 from the valve seat 110 of the valve 100 to the liquid storage tank 10.
The flow path volume V1 refers to the volume from the valve seat 110 of the valve 100 to the end of the suction side SS of the pump 20. The flow path volume V <b> 1 of the present embodiment is the total of the partial volume of the valve box 160 located on the secondary side DW from the valve seat 110 and the internal volume of the ground portion 53 of the liquid suction pipe 50.
The flow path volume V <b> 2 refers to the volume from the valve seat 110 of the valve 100 to the lower end of the underwater portion 51 of the liquid suction pipe 50. The flow path volume V <b> 2 of the present embodiment is the total of the partial volume of the valve box 160 located on the primary side UP with respect to the valve seat 110 and the in-pipe volumes of the upper water portion 52 and the underwater portion 51 of the liquid suction pipe 50.

  The pumping system 1000 of the present embodiment is sufficient when the pump 20 is started because the flow volume V1 between the valve seat 110 and the pump 20 is larger than the flow volume V2 upstream of the valve seat 110. Expiratory water is supplied. In other words, when the entire amount of water in the flow channel volume V1 is used as expiratory water when the pump 20 is started, the liquid L sucked up from the liquid storage tank 10 through the underwater portion 51 exceeds the valve seat 110. For this reason, the inside of the surface portion 52 and the ground portion 53 is filled with the liquid L, and pumping is started by the subsequent operation of the pump 20.

  The holding force F2 that the valve body 220 of the second check valve 200 closes the opening 212 is larger than the pressing force F1 that the valve body 120 of the first check valve 100 closes the opening 112. Here, the holding forces F1 and F2 are forces necessary for the drained closed valve bodies 120 and 220 to be separated from the valve seats 110 and 210, respectively. Specifically, it is a resultant force of the urging force of the elastic bodies 130 and 230 and the gravity (self-weight) acting on the valve bodies 120 and 220. Since the pressing force F1 of the first check valve 100 is smaller than the pressing force F2 of the second check valve 200, the liquid storage tank 10 can be passed through the first check valve 100 even in the low speed operation at the beginning of the operation of the pump 20. The liquid L can be sucked up by the liquid absorption pipe 50. On the other hand, since the pressing force F2 of the second check valve 200 is larger than the pressing force F1 of the first check valve 100, the valve body 220 of the second check valve 200 is quickly closed when the operation of the pump 20 is stopped. Thus, the discharge of the liquid L is blocked.

  Here, when the pumping operation of the pump 20 is stopped, the discharge amount of the liquid L decreases rapidly and continuously. When the internal pressure of the discharge pipe 60 decreases due to a decrease in the discharge amount, the valve body 220 of the second check valve 200 is urged by the elastic body 230 to close the opening 212. The valve body 220 pushes the liquid L inside the valve box 260 back to the inlet 216 of the primary side UP. Since a new liquid L is discharged from the pump 20 while the discharge amount gradually decreases, the internal pressure of the discharge pipe 60 increases. That is, the internal pressure once decreased due to the decrease in the discharge amount starts to increase again. This increase in internal pressure is transmitted as a backflow to the pump 20 and the liquid suction pipe 50 and reaches the first check valve 100.

  In the pumping system 1000 of the present embodiment, when the pumping operation of the pump 20 is stopped, the valve body 120 of the first check valve 100 is after the second check valve 200 is closed and the second reverse valve. The opening 112 is closed before the back flow of the liquid L generated by closing the stop valve 200 reaches the first check valve 100 via the pump 20. Thereby, since the valve body 120 of the first check valve 100 closes the opening 112 before reaching the backflow after the pump 20 is stopped, the first check valve 100 can be prevented from falling.

  Such a pumping system 1000 is realized by setting a spring constant k satisfying the following expression (1) in the elastic body 130.

In Expression (1), k is a spring constant of the elastic body 130 of the first check valve 100.
L ₁ is the path length from the suction side SS of the pump 20 to the valve seat 110 of the first check valve 100. L ₂ is the path length from the suction side SS of the pump 20 to the valve body 120 of the first check valve 100. L is the path length from the suction side SS of the pump 20 to the liquid level FL. S is an average opening area of the liquid suction pipe 50. D is the area of the valve body 120. ρ is the density of the liquid L. π is the circumference ratio.
Δx ₁ is the compression length from the natural length of the elastic body 130 in the closed state. Δx ₂ is the compression length from the natural length of the elastic body 130 during the steady operation (open state) of the pump 20.
P _S (0) is the absolute value of the suction pressure during the steady operation of the pump 20. The absolute value of the suction pressure refers to the amount of pressure drop at the suction side SS of the pump 20. v is an average flow velocity in the flow direction F during steady operation of the pump 20.
τ is the closing delay time of the first check valve 100. The time (backflow arrival time) until the backflow generated when the second check valve 200 is closed reaches the valve body 120 of the first check valve 100 is defined as tr, where the stop of the pump 20 is zero. Let u be the average moving speed of the valve body 120 from when the pump 20 stops until the first check valve 100 reaches the closed state. The closing delay time τ of the first check valve 100 is expressed by the following equation (2).

(Equation 2)
τ = tr−Δx ₂ / u (2)

In the formula (1), P _S (τ) is the residual suction pressure (≧ 0) of the pump 20 at the moment when the closing delay time has elapsed since the pump stop (closing delay time). v ′ is the average flow velocity in the flow direction F at the closing delay time.

  The left side of the above equation (1) represents the lower limit of the spring constant k of the elastic body 130 that is sufficient for the valve body 120 to reach the closed state faster than the backflow reaches the valve body 120 of the first check valve 100. . The right side of the above equation (1) represents the upper limit of the spring constant k of the elastic body 130 for allowing the liquid L to be sucked by opening the valve body 120 of the first check valve 100 in the steady operation of the pump 20. ing.

  By setting the backflow arrival time tr and the spring constant k of the elastic body 130 based on the characteristic values of the pumping system 1000, the valve body 120 of the first check valve 100 before reaching the backflow generated after the pump 20 is stopped. Can be constructed. The characteristic values of the pumping system 1000 include the parameters included in the equation (1), the pipe lengths of the liquid suction pipe 50 and the discharge pipe 60, the installation position of the second check valve 200, the spring constant of the elastic body 230, and the pump. There are 20 pump characteristic values.

When the vertical distance H1 between the valve seat 210 of the second check valve 200 and the discharge side DS of the pump 20 increases, the backflow generation time tr increases and P _S (τ) decreases. For this reason, together with the spring constant k, the vertical distance H1 may be adjusted as a variable so as to satisfy the above formula (1).

<Second embodiment>
4 (a) and 4 (b) are longitudinal sectional views of the valve 100 of the second embodiment of the present invention.

  The valve 100 of this embodiment is a lift type check valve including a valve seat 110, a valve body 120, and an elastic body 130, and is common to the first embodiment in that it is provided on the ground portion 53 of the liquid suction pipe 50. The valve seat 110 includes an opening 112 through which the liquid L flows. The valve body 120 linearly reciprocates in a direction approaching or separating from the opening 112 (the left-right direction in FIG. 4A) to close the opening 112 so as to be freely opened and closed. The elastic body 130 urges the valve body 120 toward the valve seat 110.

  The valve 100 of this embodiment is different from that of the first embodiment in that the valve 100 is a straight valve in which the reciprocating direction of the valve body 120 matches the axial flow direction AF. The axial flow direction AF of the valve 100 of the present embodiment is an average of the flow direction F (see FIG. 4B) of the liquid L from the primary side UP to the secondary side DW. The linear direction is parallel to the guide shaft 122. A support portion 124 provided inside the valve box 160 holds the guide shaft 122 slidably in the axial direction AF. The primary side UP inlet 116 and the secondary side DW outlet 132 face each other.

  Also in the present embodiment, the ground portion 53 of the liquid suction pipe 50 from the valve 100 to the pump 20 is arranged to be inclined upward with a predetermined gradient φ toward the pump 20 (see FIG. 1). At this time, the drainage of the valve 100 is favorably performed by attaching the valve 100 to the ground portion 53 with the bypass passage 169 and the falling water valve 168 directed vertically downward.

  Similar to the first embodiment, the valve 100 of the present embodiment also includes an opening-side guide 150 that guides the reciprocation of the valve body 120. The opening side guide 150 is provided on one of the valve seat 110 and the valve body 120 (the valve seat 110 in the present embodiment), and protrudes toward the other (the valve body 120 in the present embodiment). The radial clearance between the opening-side guide 150 and the other (the valve body 120) is such that the valve body 120 is separated from the opening 112 from the state where the valve body 120 closes the opening 112 (see FIG. 4A). It is configured to increase gradually as it goes on.

  The opening side guide 150 of this embodiment is composed of a plurality of protruding claw portions 152 that protrude from the valve seat 110 to the secondary side DW. The plurality of protruding claws 152 are arranged on the ring so as to be separated from each other along the peripheral wall 114 of the valve seat 110. In the closed state of the valve 100, the inner main surface 154 of the plurality of protrusions 152 slides with the side peripheral surface of the valve body 120.

  As for the opening side guide 150 of this embodiment, the thickness of each protrusion nail | claw part 152 is small toward the front end side (namely, secondary side DW). The main surface 154 on the inner side of the protrusion 152 is inclined with respect to the axial direction AF. Specifically, the main surface 154 of the projecting claw portion 152 is inclined outward in the radial direction toward the distal end side (secondary side DW). The valve body 120 has a disc shape, and its side peripheral surface has a straight cylindrical shape. As a result, the radial clearance between the projecting claw 152 and the valve body 120 gradually increases as the valve body 120 moves away from the opening 112 from the closed state of the valve body 120 (see FIG. 4A). To do. Therefore, similarly to the valve 100 of the first embodiment, the flow path area of the liquid L in the open state is sufficiently secured, and the reproducibility of the relative position between the valve body 120 and the valve seat 110 in the closed state is ensured. It is good.

  Similar to the first embodiment, the opening-side guide 150 has a tapered shape in which the width dimension (the circumferential dimension of the opening 112) decreases toward the distal end side in the protruding direction. The projecting claw portion 152 constituting the opening side guide 150 of the present embodiment has a tapered shape in which the circumferential dimension continuously decreases toward the secondary side DW.

<Third embodiment>
FIGS. 5A and 5B are longitudinal sectional views of the valve 100 according to the third embodiment of the present invention.

  The valve 100 of the present embodiment is a lift type check valve including a valve seat 110, a valve body 120, and an elastic body 130. It is common to the first and second embodiments in that it is provided on the ground portion 53 of the liquid suction pipe 50 that inclines toward the pump 20 with a predetermined gradient φ. As in the second embodiment, the valve 100 is a straight valve in which the reciprocating direction of the valve body 120 matches the axial flow direction AF.

  The pumping system 1000 of the present embodiment includes an installation base 300 that holds the valve 100 obliquely. The installation base 300 holds the valve 100 such that the position of the secondary side DW is higher than the primary side UP of the valve 100. The inclination angle θ of the guide shaft 122 of the valve 100 is equal to the gradient φ of the ground portion 53 of the liquid suction pipe 50.

  The valve 100 is common to the first and second embodiments in that it includes an opening side guide 150 that guides the reciprocating motion of the valve body 120. The opening side guide 150 is provided on one of the valve seat 110 and the valve body 120 (the valve body 120 in the present embodiment), and protrudes toward the other (the valve seat 110).

  In the present embodiment, the thickness of the protruding claw portion 152 is constant, and the peripheral wall 114 of the opening 112 in the valve seat 110 is reduced in a bowl shape toward the primary side UP. Thus, the radial clearance between the opening side guide 150 and the other (the valve seat 110) is such that the valve body 120 is opened from the state where the valve body 120 closes the opening 112 (see FIG. 5A). It is comprised so that it may increase gradually as it leaves | separates from 112.

<Fourth embodiment>
FIG. 6 is a diagram showing an overall configuration of a pumping system 2000 according to the fourth embodiment of the present invention. This embodiment is common to the first embodiment in that the valve 100 is provided on the ground portion 53 of the liquid suction pipe 50. In the valve 100 of this embodiment, the primary side UP communicates with the inside of the liquid storage tank 10, and the secondary side DW communicates with the pump 20, so that the liquid suction pipe 50 is shut open. In addition, when the pump 20 is stopped, the primary side UP (the water portion 52) of the liquid suction pipe 50 is filled with the liquid L and has the same negative pressure as the first embodiment.

  The pumping system 2000 of this embodiment is provided with the 2nd pumping line 410 in which the other pump 20b was provided in addition to the 1st pumping line 400 in which the valve 100 and the pump 20 were provided. The first pumping line 400 is common to the pumping system 1000 of the first embodiment, except that the lower end 55 of the liquid suction pipe 50 located inside the liquid storage tank 10 is opened upward. In the pumping system 2000 of the present embodiment, the expiratory tank 24 and the on-off valve 26 (see FIG. 1) are not shown.

  That is, in the pumping system 2000 of the present embodiment, the lower end portion 55 of the liquid suction pipe 50 connected to the primary side UP of the valve 100 opens vertically upward. For this reason, the pumping system 2000 sucks and lifts the liquid L from above the lower end portion 55 of the liquid suction pipe 50. Foreign matter such as sludge having a specific gravity greater than that of the liquid L may be deposited at the bottom of the liquid storage tank 10. Here, when the lower end part of the liquid absorption pipe is opened downward, it is easy to suck the foreign matter at the bottom part. For this reason, it is necessary to arrange | position a lower end part in the upper direction spaced apart from the bottom part of the liquid storage tank 10 so that a foreign material may not be attracted | sucked. Therefore, when the lower end portion of the liquid suction pipe is opened downward, the liquid L in the vicinity of the bottom of the liquid storage tank 10 cannot be pumped, and a lot of waste is generated in the liquid L. On the other hand, when the lower end portion 55 of the liquid suction pipe 50 is opened upward and the lower portion is closed like the pumping system 2000 of the present embodiment, it is difficult to suck foreign matter at the bottom of the liquid storage tank 10, The lower end 55 can be disposed in the vicinity of the bottom. For this reason, the liquid L can be used efficiently without waste.

  A foot valve 56 that is a check valve is provided at the lower end of the liquid suction pipe 50 b of the second lifting line 410. One end (lower end) of the liquid suction pipe 50 b is immersed in the liquid L stored in the liquid storage tank 10. The other end of the liquid suction pipe 50b is connected to the suction side SS of the pump 20b. Of the liquid suction pipe 50b, a region immersed in the liquid L is referred to as an underwater portion 51b, and a region extending substantially vertically above the liquid surface FL is referred to as a water portion 52b. A region connected to the water portion 52b and installed substantially horizontally and connected to the pump 20b is referred to as a ground portion 53b. A discharge pipe 60b is connected to the discharge side DS of the pump 20b, and a check valve 200b and an on-off valve 280b are provided on the discharge pipe 60b. The first pumping line 400 and the pumping system 1000 of the first embodiment are used. And in common.

  When the drive unit 22b of the pump 20b is driven, the liquid L is sucked from the foot valve 56, the liquid L is pumped through the liquid suction pipe 50, and the liquid L is supplied to a desired application through the discharge pipe 60b. When the liquid L is pumped by the second pumping line 410, the liquid level FL of the liquid storage tank 10 gradually falls. When the liquid level FL decreases and the foot valve 56 is exposed from the liquid level FL, air enters the liquid suction pipe 50b. When the liquid suction pipe 50b becomes empty, the liquid L cannot be sucked up by the pump 20b. After that, even if the liquid L is supplied to the liquid storage tank 10 and the liquid level FL becomes higher than the foot valve 56 again, the ground portion 53b of the liquid suction pipe 50b is empty, so unless priming is performed. The pump 20b cannot be restarted. For this reason, only the second pumping line 410 has a problem that the pumping stops for a predetermined time when the liquid level FL of the liquid storage tank 10 is unexpectedly lowered.

  On the other hand, by providing the first pumping line 400 of this embodiment as a backup line, the pumping system 2000 pumps the liquid L again as soon as the water level of the liquid level FL recovers higher than the lower end 55. Can do. During or before the liquid L is being pumped in the second pumping line 410, the pump 20 of the first pumping line 400 is driven to start the liquid L from the lower end 55 of the liquid suction pipe 50. And the liquid absorption tube 50 is filled with the liquid L. In this state, the valve 100 is closed. The valve 100 is a check valve as in the first embodiment, and when the pump 20 is stopped, the valve 100 is closed without the liquid L falling from the liquid suction pipe 50.

  FIG. 7A is a schematic cross-sectional view showing a first example of the lower end portion 55 of the liquid suction pipe 50. FIG. 7B is a schematic cross-sectional view showing a second example of the lower end portion 55 of the liquid suction pipe 50. FIGS. 7A and 7B show a state in which the liquid level FL has dropped from the state of FIG. 6 and the liquid level FL has become lower than the pipe end 57 of the liquid suction pipe 50. This occurs when the liquid L stored in the liquid storage tank 10 is pumped by a predetermined amount or more by the pump 20. Since the valve 100 of the first pumping line 400 is closed, atmospheric pressure acts on the liquid end surface EL of the lower end portion 55 of the liquid suction pipe 50. However, when the lower end portion 55 is opened downward, the liquid end surface EL of the lower end portion 55 of the liquid suction pipe 50 becomes unstable due to contact with the oscillation of the liquid level FL of the liquid storage tank 10 and the flow of ambient air. Then, air enters the inside of the liquid suction pipe 50 and falls as a result.

  On the other hand, the lower end portion 55 of the liquid suction pipe 50 of the first example shown in FIG. 7A is bent at a bending angle of about 180 degrees, and the pipe end 57 faces upward. The liquid end face EL of the liquid absorption pipe 50 is in the vicinity of the pipe end 57.

  The lower end portion 55 of the second example of the liquid suction pipe 50 shown in FIG. 7B includes a pipe end 57 of the liquid suction pipe 50 opened downward, a water holding part 58 that opens upward and accommodates the pipe end 57, It has. The liquid end surface EL of the liquid absorption pipe 50 is in the vicinity of the upper surface of the water retention part 58. The pipe end 57 of the liquid absorption pipe 50 is located below the liquid end face EL and is immersed in the liquid L. The pipe end 57 and the water retention part 58 are integrally connected. The area of the upper surface where the water retention part 58 is opened, that is, the area of the liquid end surface EL is referred to as the opening area of the water retention part 58. The opening area of the water retaining portion 58 is not particularly limited, but is preferably larger than the opening area of the pipe end 57 of the liquid suction pipe 50.

  As shown in FIGS. 7A and 7B, the liquid absorption pipe 50 is filled with the liquid L up to the lower end portion 55, and the lower end portion 55 (the pipe end 57 or the water retaining portion 58) is upward. It is open. For this reason, in order for the air AR to enter the liquid absorption pipe 50, it is necessary that the air AR sinks downward from the liquid end surface EL and exceeds the lowermost part of the liquid absorption pipe 50. The lowermost part of the liquid suction pipe 50 is the curved portion 59 of the lower end portion 55 in the case of the first example in FIG. 7A, and the pipe end 57 in the case of the second example in FIG. . Even if the liquid end surface EL of the liquid absorption pipe 50 becomes unstable, the air AR does not enter the liquid absorption pipe 50. For this reason, the first pumping line 400 can maintain the priming state regardless of the water level of the liquid level FL of the liquid storage tank 10. Therefore, if the water level of the liquid level FL in the liquid storage tank 10 is restored, the liquid L can be immediately pumped up using the first pumping line 400. Then, during the pumping of the liquid L by the first pumping line 400, priming water can be supplied to the liquid suction pipe 50b of the second pumping line 410, and the operation of the pump 20b can be resumed. Thereby, according to the pumping system 2000, even if the liquid level FL of the liquid storage tank 10 falls unexpectedly, the stop time of the pumping of the liquid L can be made extremely short.

  By providing the water retaining portion 58 upward at the tube end 57 as in the second example shown in FIG. 7B, the liquid end surface EL can be easily stabilized without curving the lower end portion 55 of the liquid suction tube 50. be able to.

  The minimum area of the flow path of the lower end 55 from the underwater portion 51 (see FIG. 6) of the liquid suction pipe 50 to the liquid end surface EL is equal to the opening area of the underwater portion 51 of the liquid suction pipe 50. In other words, there is no bottleneck in the flow path of the liquid suction pipe 50 at the lower end 55. That is, the opening area of the curved portion 59 and the pipe end 57 constituting the lower end portion 55 of the first example, and the flow path area inside the water retention portion 58 constituting the lower end portion 55 of the second example are the same as those of the liquid absorption pipe 50. It is equal to or larger than the opening area of the underwater portion 51. Thereby, the lower end 55 can be opened upward without insufficient suction of the liquid L.

  The lower end 55 of the liquid suction pipe 50 of the first pumping line 400 may be lower than the foot valve 56 at the lower end of the liquid suction pipe 50b of the second pumping line 410. When the liquid level FL decreases and the pumping in the second pumping line 410 becomes impossible, the lower end 55 of the liquid suction pipe 50 is immersed in the liquid level FL in a priming state, so By operating the pump 20 of one pumping line 400, the pumping of the liquid L is not substantially stopped.

  In FIG. 6, the pumping system 2000 including the first pumping line 400 having the lower end 55 opened upward and the second pumping line 410 provided with the foot valve 56 is illustrated. Not limited. A pumping system including only the first pumping line 400 may be used. According to the first pumping line 400, the water stoppage force by the valve 100 and the lower end portion 55 opening upwardly synergistically prevent water falling from the water portion 52 of the liquid suction pipe 50. For this reason, even when the liquid L is drained from the liquid storage tank 10 and the inside of the liquid storage tank 10 is inspected, the primary side of the liquid suction pipe 50 is held in a state where water has passed therethrough. Therefore, if the liquid L is stored again in the liquid storage tank 10, the pump 20 can immediately resume pumping without priming the liquid suction pipe 50.

<Fifth embodiment>
FIG. 8 is a diagram showing an overall configuration of a pumping system 3000 according to the fifth embodiment of the present invention. This embodiment is common to the first embodiment in that the valve 103 is provided on the ground portion 53 of the liquid suction pipe 50. In the valve 103 of this embodiment, the primary side UP communicates with the inside of the liquid storage tank 10, and the secondary side DW communicates with the pump 20, so that the liquid suction pipe 50 is shut open.

  The valve 103 of the present embodiment is a check valve that unidirectionally circulates the liquid L from the primary side UP to the secondary side DW.

  The valve (check valve) 103 of this embodiment is common to the valve 100 of the first embodiment in that it includes a valve box 160 that houses the valve body 120. The valve box 160 of the valve 103 is different from the valve 100 of the first embodiment in that the pressure reducing port 105 is formed in the primary side UP of the valve body 120. Other configurations of the valve 103 are the same as those of the valve 100 of the first embodiment.

  The decompression port 105 communicates the inside and outside of the valve box 160 and is an intake hole that decompresses the primary side UP of the valve body 120 in the valve box 160. A piping 190 is connected to the decompression port 105. The pipe 190 is provided with on-off valves 182 and 183 that shut off the flow path so as to be openable and closable. A pressure gauge 185 for measuring the static pressure inside the pipe 190 is connected to the flow path between the on-off valve 182 and the on-off valve 183.

  A vacuum pump 180 is connected to the decompression port 105. Specifically, a vacuum pump 180 is provided at the downstream side of the on-off valve 183, that is, at the end of the pipe 190. The vacuum pump 180 sucks the air inside the pipe 190 without priming.

  By opening the on-off valves 182 and 183 and operating the vacuum pump 180, the primary side UP of the pipe 190 and the valve box 160 and the water portion 52 of the liquid suction pipe 50 become negative pressure, and the water portion 51 of the liquid suction pipe 50. Liquid L is sucked up. Accordingly, the primary side UP of the valve 100 in the liquid suction pipe 50 is initially passed while the valve body 120 of the valve (check valve) 100 is closed. In this state, the on-off valve 183 is closed.

  Thus, when the pump 20 is stopped, the primary side UP (the water portion 52 and the water portion 51) of the liquid suction pipe 50 is filled with the liquid L and has a negative pressure.

  The pump 20 of this embodiment is an inverter pump. The type of the inverter pump is not particularly limited. Both a PWM method (Pulse Width Modulation) that controls the pump output by changing the current flow rate and a PAM method (Pulse Amplitude Modulation) that controls the pump output by changing the voltage value can be used. The inverter pump is a pump that has a low initial operating pressure and gradually increases the operating pressure. Therefore, the inverter pump is excellent in energy saving. However, when the primary side UP of the valve 100 is not priming, this is used as the initial water flow. It takes time to do. On the other hand, since the valve 100 of this embodiment is a check valve and the valve body 120 is closed in the initial state, even if priming water is supplied from the priming tank 24 to the liquid suction pipe 50, the water portion 52 or the water portion 51 cannot pass water. In the present embodiment, since the water portion 52 and the underwater portion 51 of the liquid suction pipe 50 can be initially passed using the vacuum pump 180, pumping can be started quickly even if an inverter pump is used for the pump 20. Can do.

  The pressure gauge 185 connected to the pipe 190 is a vacuum gauge that measures a pressure below atmospheric pressure. While the liquid L is being pumped by the pump 20, the on-off valve 182 is opened and the on-off valve 183 is closed, and the static pressure of the pipe 190 is measured by the pressure gauge 185. The pressure measured by the pressure gauge 185 is the absolute pressure or gauge pressure of the static pressure on the primary side UP of the valve box 160. When this absolute pressure is less than atmospheric pressure, that is, the gauge pressure is negative, it can be seen that the water portion 52 of the liquid suction pipe 50 is priming higher than the liquid level FL. The absolute value of the gauge pressure (negative pressure) and the priming water level (height from the liquid level FL) inside the water surface portion 52 can be converted. When the gauge pressure measured by the pressure gauge 185 reaches a predetermined pressure (negative pressure) determined based on the height of the valve body 120 from the liquid level FL, the primary side UP of the valve body 120 is completely passed. You can see that it is in a watered state. Conversely, when the gauge pressure measured by the pressure gauge 185 is substantially zero, it can be seen that the primary UP of the valve body 120 is falling.

  While the pump 20 is operated and the liquid L is being pumped, the absolute value of the gauge pressure (negative pressure) measured by the pressure gauge 185 is further increased. For this reason, according to this embodiment, based on the measured value of the pressure gauge 185, it can be discriminate | determined whether the liquid L is pumped normally.

  From the above, the quantitative water level of the priming water inside the water surface portion 52 can be detected by connecting the pressure gauge 185 to the primary side UP in the valve box 160 and measuring the static pressure. Thereby, even when the valve 103 is installed not in the end of the underwater portion 51 but in the middle as in this embodiment, it can be confirmed that the primary side UP is sufficiently initially passed. Furthermore, it can also be determined whether or not the liquid L is being pumped normally. Thereby, the idling | running | working of the pump 20 can be detected rapidly and the burning of the pump 20 can be prevented beforehand.

The above embodiment includes the following technical idea.
(1) A liquid storage tank that stores liquid, a pump that is installed on the ground and pumps the liquid, a liquid suction pipe that connects the liquid storage tank and the pump, and the liquid discharged from the pump A discharge pipe that circulates, a primary side that communicates with the interior of the liquid storage tank, a secondary side that communicates with the pump, and a check that circulates the liquid unilaterally from the primary side to the secondary side A pumping system, wherein a valve is provided on a ground portion of the liquid suction pipe.
(2) The check valve includes a valve seat having an opening through which the liquid flows, and a valve body that linearly reciprocates in a direction approaching or separating from the opening so as to open and close the opening. And an elastic body that biases the valve body toward the valve seat, and the discharge pipe has a second check valve that unidirectionally distributes the liquid discharged from the pump in the discharge direction. When the pumping operation of the pump is stopped, the valve body of the check valve is after the second check valve is closed and the second check valve is closed. The pumping system according to (1), wherein the opening is closed before the backflow of the liquid generated by the flow reaches the check valve via the pump.
(3) a valve seat provided with an opening through which the second check valve circulates the liquid, and a valve body that linearly reciprocates in the contact / separation direction with respect to the opening so as to close the opening freely. An elastic body that urges the valve body toward the valve seat, and the valve body of the second check valve has a pressing force that closes the opening, and the valve body of the check valve The pumping system according to (2) above, wherein the pumping system is larger than a pressing force for closing the opening.
(4) In the check valve and the second check valve, packings that seal the opening in a liquid-tight manner are interposed between the valve seat and the valve body, respectively, and the check valve The pumping system according to (3), wherein the packing of the valve is made of a softer material than the packing of the second check valve.
(5) The check valve includes an opening-side guide that guides the reciprocating movement of the valve body, and the opening-side guide is provided on one of the valve seat or the valve body and the valve seat or the valve The radial clearance between the opening-side guide and the other is such that the valve body moves away from the opening from the state where the valve body closes the opening. Therefore, it is comprised so that it may increase gradually, The pumping system in any one of said (2) to (4) characterized by the above-mentioned.
(6) The pumping system according to (5), wherein the opening-side guide has a tapered shape in which a width dimension decreases toward a distal end side in a protruding direction.
(7) The flow path volume (V1) from the valve seat of the check valve to the pump is larger than the flow path volume (V2) from the valve seat of the check valve to the liquid storage tank. The pumping system according to any one of 2) to (6).
(8) The pumping system according to any one of (2) to (7), wherein the ground portion of the liquid suction pipe from the check valve to the pump is inclined upward toward the pump.
(9) The pumping system according to (8), wherein a flange portion is formed on an end face on the secondary side of the check valve, and a normal direction of the flange portion is inclined obliquely upward.
(10) The check valve is an angle valve in which a reciprocating direction of the valve body and an axial flow direction intersect, and the valve body can be taken out from a valve box that houses the valve body. The pumping system according to any one of (2) to (9) above.
(11) The check valve is a straight valve in which the reciprocating direction of the valve body and the axial flow direction are parallel, and the check valve is held obliquely so that the secondary side is higher than the primary side. The pumping system according to (8), further including an installation base for performing the above operation.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2012-018567 for which it applied on January 31, 2012, and takes in those the indications of all here.

Claims (15)

A liquid storage tank for storing a liquid; a pump installed on the ground for pumping the liquid; a liquid suction pipe connecting the liquid storage tank and the pump; and the liquid discharged from the pump is circulated. A discharge pipe, and a valve with a primary side communicating with the inside of the liquid storage tank and with a secondary side communicating with the pump and shutting off the liquid suction pipe,
The valve is provided on the ground portion of the liquid suction pipe, the primary side of the liquid suction pipe is filled with the liquid, and is a negative pressure,
With the pump stopped, the primary side and the secondary side of the suction pipe are filled with the liquid, and the primary side is a negative pressure having a larger absolute value than the secondary side,
The pumping system according to claim 1, wherein the ground portion of the liquid suction pipe from the valve to the pump is inclined upward toward the pump.   The pumping system according to claim 1, wherein the valve is a check valve that unidirectionally circulates the liquid from the primary side toward the secondary side. The check valve includes a valve seat having an opening through which the liquid flows, a valve body that linearly reciprocates in a direction approaching or separating from the opening, and closing the opening so as to be openable and closable. An elastic body that urges the body toward the valve seat,
The discharge pipe is provided with a second check valve for unidirectionally circulating the liquid discharged from the pump in the discharge direction,
When the pumping operation of the pump is stopped, the valve body of the check valve is formed after the second check valve is closed and the liquid produced by the second check valve is closed. The pumping system according to claim 2, wherein the opening is closed before a reverse flow reaches the check valve via the pump. The second check valve includes a valve seat having an opening through which the liquid flows, a valve body that linearly reciprocates in the contact / separation direction with respect to the opening, and closes the opening so as to be openable and closable; An elastic body that urges the body toward the valve seat,
The pressing force that the valve body of the second check valve closes the opening is larger than the pressing force that the valve body of the check valve closes the opening. Pumping system. In the check valve and the second check valve, packings that seal the opening in a liquid-tight manner are interposed between the valve seat and the valve body, respectively.
The pumping system according to claim 4, wherein the packing of the check valve is made of a softer material than the packing of the second check valve. The check valve includes an opening side guide for guiding the reciprocation of the valve body,
The opening-side guide is provided on one of the valve seat or the valve body and protrudes toward the other of the valve seat or the valve body, and a radial clearance between the opening-side guide and the other is The valve body is configured to gradually increase from a state in which the valve body closes the opening, as the valve body is separated from the opening. The pumping system described.   The pumping system according to claim 6, wherein the opening-side guide has a tapered shape in which a width dimension decreases toward a distal end side in a protruding direction.   The flow path volume (V1) from the valve seat to the pump of the check valve is larger than the flow path volume (V2) from the valve seat to the liquid storage tank of the check valve. The pumping system as described in any one of.   The said check valve is provided with the valve box which accommodates the said valve body, The decompression port is formed in the said valve box at the primary side of the said valve body, The any one of Claim 3 to 8 characterized by the above-mentioned. The pumping system according to item.   The pumping system according to claim 9, wherein the pump is an inverter pump, and a vacuum pump is connected to the pressure reducing port.   The pumping system according to any one of claims 1 to 10, wherein a lower end portion of the liquid suction pipe located inside the liquid storage tank is opened upward.   The lower end portion of the liquid absorption pipe includes a pipe end of the liquid absorption pipe and a water retention portion that is integrally connected to the pipe end and accommodates the pipe end, and the pipe end opens downward and the water retention The pumping system according to claim 11, wherein the lower end portion of the liquid suction pipe is opened upward by opening the portion upward.   The pumping system as described in any one of Claim 1 to 10 with which the flange part is formed in the end surface of the secondary side of the said valve | bulb, and the normal line direction of the said flange part inclines diagonally upwards.   The check valve is an angle valve in which a reciprocating direction of the valve body and an axial flow direction intersect, and the valve body is configured to be removable from a valve box that houses the valve body. Item 11. The pumping system according to any one of Items 3 to 10. The check valve is a straight valve in which a reciprocating direction of the valve body and an axial flow direction are parallel,
The pumping system as described in any one of Claim 1 to 10 further equipped with the installation stand which hold | maintains the said non-return valve diagonally so that the position of the said secondary side may become higher than the said primary side.

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