JP4766539B2 - Self-priming centrifugal pump device - Google Patents

Description

  The present invention relates to a self-priming centrifugal pump apparatus that prevents water mixed with air from being fed into a water pipe.

An example of a conventional self-priming centrifugal pump device will be described with reference to FIGS. FIG. 10 is a longitudinal sectional view showing the structure of an example of a conventional self-priming centrifugal pump device. 11-16 is a figure explaining the change of operation | movement from the self-priming operation of the conventional self-priming type centrifugal pump apparatus shown in FIG. 10 until it transfers to water supply operation.

  First, the structure of a conventional self-priming centrifugal pump device will be described with reference to FIG. The pump casing 12 that surrounds the pump impeller 10 and is rotatably supported is provided with an upstream suction port 12 a and a downstream discharge port 12 b that are higher than the pump impeller 10. One end of the suction pipe 14 is connected to the suction port 12 a and the other end is immersed under the water surface of the suction water tank 16. A suction pipe is formed including a pump casing 12 upstream of the pump impeller 10 and a suction pipe 14. The pipe is horizontally arranged at an appropriate length at the highest position, and is opened and closed for water injection. Valve 18 is in communication. Further, one end of the discharge pipe 20 is connected to the discharge port 12 b and the other end is connected to the water supply pipe 24 via the discharge valve 22. A discharge pipe line is formed including the pump casing 12 and the discharge pipe 20 on the downstream side of the pump impeller 10, and the automatic exhaust valve 26 is communicated with the upper wall of the highest position. The automatic exhaust valve 26 is a valve that is automatically closed by the action of a float when the communication port becomes full.

An operation of the conventional self-priming centrifugal pump device having such a configuration that changes from the self-priming operation to the water supply operation will be described with reference to FIGS. First, the water injection opening / closing valve 18 is opened, and as shown in FIG. 11, priming water is injected to a predetermined water level where the pump impeller 10 is substantially submerged in the pump casing 12 through the valve 18. When this water pouring is completed, the water pouring valve 18 is closed. Here, the discharge valve 22 is fully opened. Next, when the pump is started with the discharge valve 22 fully opened, the priming water in the pump casing 12 moves to the discharge pipe 20 side as shown in FIG. The water level in the discharge pipe rises and a part of the air in the discharge pipe is discharged to the outside through the automatic exhaust valve 26. Further, water is sucked into the suction pipe 14 from the suction water tank 16, and the water surface rises. Further, as shown in FIG. 13, as the operation continues, the water level in the discharge pipe rises further, and the air in the discharge pipe is discharged to the outside through the automatic exhaust valve 26 , and in the suction pipe The water level also rises and finally reaches the lower inner wall of the highest position of the suction pipe. Then, the water in the suction pipe flows down to the position where the pump impeller 10 in the pump casing 12 is disposed over the lower inner wall at the highest position. Here, water can flow smoothly from the suction pipe to the position where the pump impeller 10 is disposed by leveling the pipe at an appropriate length at the highest position of the suction pipe. As the water flows from the suction pipe, the water level in the discharge pipe rises abruptly as shown in FIG. At this time, an air reservoir 28 is formed by the remaining air below the upper side wall of the highest position of the suction pipe. Eventually, the water surface in the discharge pipe reaches the communication port of the automatic exhaust valve 26, and the automatic exhaust valve 26 is automatically closed as shown in FIG. Here, the air in the air reservoir 28 in the suction pipe is entrained and moved along with the flow of water in the form of bubbles on the discharge pipe side, and the water mixed with the air is fed to the water feed pipe 24. Then, as shown in FIG. 16, when all the air in the air reservoir 28 in the suction conduit is moved to the discharge conduit side and the air reservoir 28 disappears, the self-priming operation is completed, and water that does not contain air enters the water supply tube. 24 is sent to the water supply operation.

  In the conventional self-priming centrifugal pump device as described above, water mixed with air is fed to the water supply pipe 24 in the final stage of the self-priming operation, and there is a possibility that an air hammer phenomenon will occur in the water supply pipe 24. is there. In particular, when the suction pipe is long, the amount of air flowing into the water supply pipe 24 increases accordingly, and the water supply pipe 24 may be greatly damaged by the air hammer phenomenon.

The inventors previously disclosed in Japanese Patent Application Laid-Open No. 2002-371985, the water in the air-water mixed state discharged from the pump impeller is separated into air and water by a gas-liquid separator, and the separated water is pumped. A technique was proposed to quickly eliminate the air pocket generated in the suction pipe by returning it to the suction side of the impeller. However, this proposed technique can shorten the time from the self-priming operation to the water supply operation, but does not improve the water supply of the water mixed with air on the water supply pipe side.
JP 2002-371985 A

  The present invention has been made in view of the circumstances of the prior art, and an object of the present invention is to provide a self-priming centrifugal pump device that prevents water mixed with air from being fed into a water pipe.

The present invention has been made to solve the above-described problems, and the self-priming centrifugal pump apparatus of the present invention includes a pump casing upstream of the pump impeller and a suction pipe communicating with the suction port. A part of the suction pipe formed is positioned higher than the pump impeller and includes a pump casing on the downstream side of the pump impeller and a discharge pipe communicating with the discharge port. In the self-priming centrifugal pump device in which a part of the discharge pipe is positioned higher than the pump impeller and the discharge pipe is provided with an openable / closable discharge valve, the highest position of the discharge pipe One end of the exhaust pipe is communicated with the upper side wall, and a control valve that can be opened and closed is provided on the exhaust pipe . The pump discharge pressure is set to be 0.12 MPa or more, and the exhaust pipe and the control valve in the opened state are connected. Minimum cross-sectional area 1 and the ratio S1 / S2 of the suction pipe suction pipe position where the air reservoir is formed of a passage path cross-sectional area S2 is formed by setting so that 0.11 or more.

In the self-priming centrifugal pump device according to claim 1, when the self-priming operation is started with the discharge valve closed and the control valve opened, air in the discharge pipe passes through the control valve and the exhaust pipe. In addition, the air in the suction pipe is discharged to the outside through the control valve and the exhaust pipe together with the priming water and the water sucked from the suction water tank. When all the air in the suction pipe and the discharge pipe is exhausted to the outside, the control valve is closed and the discharge valve is opened, so that water that is not mixed in the water supply pipe is first Can be fed from . The ratio of the minimum cross-sectional area S1 of the exhaust pipe and the open control valve to the suction pipe cross-sectional area S2 at the position where the air reservoir of the suction pipe is formed is that the pump discharge pressure is 0.12 MPa. Since S1 / S2 is set to be 0.11 or more, it has been experimentally confirmed that the air in the air reservoir generated in the suction pipe is surely discharged to the outside. Here, when the discharge pressure of the pump is larger than 0.12 MPa, the flow velocity in the suction pipe increases, and the air in the air pool is transferred to the discharge pipe side more effectively. The accumulated air can be discharged to the outside.

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing the structure of an embodiment of the self-priming centrifugal pump apparatus of the present invention. 2 to 8 are diagrams for explaining a change in operation from the self-priming operation of the embodiment of the self-priming centrifugal pump apparatus of the present invention shown in FIG. 1 to the transition to the water feeding operation. FIG. 9 shows that the discharge pressure of the pump is set to 0.12 MPa, the minimum cross-sectional area S1 of the exhaust pipe and the open control valve, and the suction pipe cross-sectional area S2 at the position where the air reservoir of the suction pipe is formed. It is a figure which shows the result of having measured the change of the residual amount of the air of the air pool with respect to the change of ratio S1 / S2. 1 to FIG. 8, the same or equivalent members as those shown in FIG. 10 to FIG.

  The structure of the self-priming centrifugal pump apparatus of the present invention shown in FIG. 1 is different from the structure of the conventional self-priming centrifugal pump apparatus shown in FIG. 10 as follows. Instead of the automatic exhaust valve 26 disposed on the upper side wall at the highest position of the discharge pipe, one end of the exhaust pipe 30 is communicated, and a control valve 32 that can be opened and closed is interposed in the exhaust pipe 30. The other end of the exhaust pipe 30 is disposed so as to be opened on the water surface of the suction water tank 16.

The operation of the self-priming centrifugal pump apparatus of the present invention having such a configuration that changes from the self-priming operation to the water supply operation will be described with reference to FIGS. First, the on-off valve 18 for water injection is opened, and as shown in FIG. 2, priming water is injected to a predetermined water level L at which the pump impeller 10 is almost submerged in the pump casing 12 through the water on-off valve 18. To do. When this water pouring is completed, the water pouring valve 18 is closed. Here, the control valve 32 is opened, and the discharge valve 22 is fully closed. Next, when the pump is started with the discharge valve 22 fully closed and the control valve 32 opened, the pump impeller 10 rotates, as shown in FIG. The priming water moves to the discharge pipe 20 side, the water surface in the discharge pipe rises, and part of the air in the discharge pipe is discharged to the outside through the exhaust pipe 30 and the control valve 32. Further, water is sucked into the suction pipe 14 from the suction water tank 16, and the water surface rises. Further, as shown in FIG. 4, the water level in the discharge pipe rises further as the operation continues, and the air in the discharge pipe is discharged to the outside through the exhaust pipe 30 and the control valve 32, and the suction pipe The water level in the channel also rises and finally reaches the lower inner wall at the highest position of the suction pipe. Then, the water in the suction pipe flows down to the position where the pump impeller 10 in the pump casing 12 is disposed over the lower inner wall at the highest position. As the water flows from the suction pipe 14, as shown in FIG. 5, the water level in the discharge pipe rises rapidly and reaches the communication position of the exhaust pipe 30, and further through the exhaust pipe 30 and the control valve 32. It is discharged to the suction water tank 16. At this time, an air reservoir 28 is formed by the remaining air below the upper side wall of the highest position of the suction pipe. Then, as shown in FIG. 6, the air in the air reservoir 28 in the suction pipe is entrained and moved to the discharge pipe along with the flow of water, and the water mixed with the air passes through the exhaust pipe 30 and the control valve 32. Thus, the air discharged into the suction water tank 16 and remaining in the air reservoir 28 is reduced. Further, as shown in FIG. 7, when all the air in the air reservoir 28 in the suction pipe is moved to the discharge pipe side and the air reservoir 28 disappears completely, the self-priming operation ends. Therefore, as shown in FIG. 8, the control valve 32 is closed and the discharge valve 22 is opened, so that water not mixed with air is supplied to the water supply pipe 24 and the water supply operation is performed.

By the way, in the state shown in FIG. 6, when the air in the air reservoir 28 in the suction pipe is entrained by the water flow, the air entrainment becomes more effective as the flow velocity of the water flow in the air reservoir 28 in the suction pipe increases. Expected to be made. In order to increase the flow velocity, the minimum cross-sectional area of the exhaust pipe 30 and the opened control valve 32 is increased so that water can easily pass through, and the discharge pressure of the pump is increased. Is a factor. Therefore, the inventors set the discharge pressure of the pump to 0.12 MPa, which is the lowest discharge pressure used in a general pump, and the minimum cross-sectional area S1 of the exhaust pipe 30 and the control valve 32; The change in the residual amount of air in the air reservoir 28 with respect to the change in the ratio S1 / S2 of the suction pipe cross-sectional area S2 at the position where the air reservoir 28 in the suction conduit is formed was measured by experiment. The result is shown in FIG. This is a measured value in a state where the operation is continued for about 20 minutes from the state shown in FIG. 6 and the residual amount of air in the air reservoir 28 is not changed. In FIG. 9, as S1 / S2 increases, that is, as the minimum cross-sectional area S1 of the exhaust pipe 30 and the opened control valve 32 increases, the residual amount of air decreases, and the residual amount of air when S1 / S2 is 0.11. Is 0. Therefore, if S1 / S2 is 0.11 or more, the air in the working air reservoir 28 is surely moved to the discharge pipe side. Obviously, the greater the discharge pressure of the pump, the easier the air is taken from the air reservoir 28. Therefore, if the pump discharge pressure is greater than 0.12 MP, S1 / S2 may be smaller than 0.11, but the limit can be easily measured by experiment.

  In the above embodiment, the suction pipe 14 is directly connected to the suction port 12a of the pump casing 12 to form the suction pipe. However, the present invention is not limited to this, and a straight pipe is provided between the suction port 12a and the suction pipe 14. Alternatively, the suction pipe may be formed by appropriately interposing a curved pipe. Further, in the discharge pipe, a straight pipe or a curved pipe may be appropriately interposed between the discharge port 12 b of the pump casing 12 and the discharge pipe 20. In the above embodiment, the suction port 12 a and the discharge port 12 b of the pump casing 12 are both provided at a position higher than the pump impeller 10, so that a part of the suction conduit and the discharge conduit is more than the pump impeller 10. However, the present invention is not limited to this, and a part of the suction pipe 14 connected to the suction port 12a is arranged higher than the pump impeller 10, and the discharge pipe 20 connected to the discharge port 12b is connected. May be arranged higher than the pump impeller 10. Further, the pipes of the suction pipe 14 and the discharge pipe 20 are not limited to steel pipes, and plastic pipes, flexible pipes and hoses may be used.

It is a longitudinal cross-sectional view which shows the structure of the Example of the self-priming vortex pump apparatus of this invention. FIG. 2 is a view showing a state in which priming water is poured to a predetermined water level where the pump impeller is almost submerged in the pump casing in order to start the self-priming operation in the embodiment of the self-priming centrifugal pump apparatus of the present invention shown in FIG. With the control valve open and the discharge valve closed, the pump is started, and with the rotation of the pump impeller, the priming water in the pump casing moves to the discharge pipe side, the water level in the discharge pipe rises, and the discharge pipe It is a figure which shows the state which a part of air in a path | pass passes through an exhaust pipe and a control valve, is discharged | emitted outside, water is sucked in from the suction water tank in the suction pipe, and the water surface rose. As the operation continues further, the water level in the discharge pipe rises further, the air in the discharge pipe passes through the exhaust pipe and the control valve and is discharged to the outside, and the water level in the suction pipe also rises. FIG. 11 is a view of a state where the lower inner wall is finally reached at the highest position of the suction pipe. The water in the suction pipe passes over the lower inner wall at the highest position and flows down to the position where the pump impeller in the pump casing is disposed, the water level in the discharge pipe rises rapidly, and the exhaust pipe and It is a figure which shows that an air pocket is formed by the air which passes through a control valve, is returned to an intake water tank, and also remains under the upper wall of the highest position of an intake pipe line. A state where air in the air reservoir in the suction pipe is entrained and moved to the discharge pipe along with the flow of water, and the mixed water passes through the exhaust pipe and the control valve and is returned to the suction water tank. FIG. All of the air in the suction pipe is moved to the discharge pipe side, the air pool disappears, the self-priming operation ends, and water that does not contain air passes through the exhaust pipe and the control valve, and the suction water tank it is a diagram showing a state to be returned to. It is a figure which shows the state which the control valve was closed and the discharge valve was opened, and the water which did not mix air was sent to the water supply pipe, and became water supply operation. The discharge pressure of the pump is set to 0.12 MPa, and the ratio S1 / S2 between the minimum cross-sectional area S1 of the exhaust pipe and the open control valve and the suction pipe cross-sectional area S2 at the position where the air reservoir of the suction pipe is formed. It is a figure which shows the result of having measured the change of the residual amount of the air of the air pool with respect to the change of. It is a longitudinal cross-sectional view which shows the structure of an example of the conventional self-priming type centrifugal pump apparatus. FIG. 11 is a view showing a state in which priming water is injected to a predetermined water level where the pump impeller is substantially submerged in the pump casing in order to start the self-priming operation of the example of the conventional self-priming centrifugal pump device shown in FIG. 10. With the discharge valve fully opened, the pump is started, and as the pump impeller rotates, the priming water in the pump casing moves to the discharge pipe side, and the water level in the discharge pipe rises to raise the discharge pipe. It is a figure which shows the state which a part of air in was discharged | emitted outside via an automatic exhaust valve, the water was drawn in into the suction pipe, and the water surface rose. As the operation continues, the water level in the discharge pipe rises further and the air in the discharge pipe is discharged to the outside through the automatic exhaust valve, and the water level in the suction pipe also rises. It is a figure of the state which reached the lower inner wall of the highest position of a suction pipe line. The water in the suction pipe flows down to the position where the pump impeller in the pump casing is placed over the lower inner wall where the water is the highest, and the water level in the discharge pipe rises rapidly. It is a figure which shows that water supply is started and an air pocket is formed by the air which remains under the upper side wall of the highest position of a suction pipe line. The water surface in the discharge pipe reaches the communication port of the automatic exhaust valve, the automatic exhaust valve is automatically closed, and air in the air reservoir in the suction pipe becomes bubbles on the discharge pipe side along with the flow of water. It is a figure which shows the state in which the water which was moved and was mixed and air was mixed is sent. All the air in the air reservoir in the suction pipe is moved to the discharge pipe side, the air pool disappears, the self-priming operation is completed, and water that does not contain air is fed from the water pipe and becomes the water feeding operation. It is a figure which shows a state.

DESCRIPTION OF SYMBOLS 10 Pump impeller 12 Pump casing 12a Suction port 12b Discharge port 14 Suction pipe 16 Suction water tank 18 Injection valve 20 Discharge pipe 22 Discharge valve 24 Water supply pipe 26 Automatic exhaust valve 28 Air reservoir 30 Exhaust pipe 32 Control valve

Claims (1)

A part of the suction pipe formed by including a pump casing upstream of the pump impeller and a suction pipe communicating with the suction port is positioned higher than the pump impeller, and the pump impeller A part of the discharge pipe formed by including the pump casing on the downstream side and the discharge pipe communicating with the discharge port is located at a position higher than the pump impeller, and can be opened and closed to the discharge pipe. In the self-priming spiral pump device provided with a discharge valve, one end of the exhaust pipe is communicated with the upper wall of the highest position of the discharge pipe, and a control valve that can be opened and closed is provided in the exhaust pipe, so that the pump discharge pressure is 0 The ratio S1 / of the suction pipe cross-sectional area S2 at the position where the minimum cross-sectional area S1 of the exhaust pipe and the opened control valve is formed and the air reservoir of the suction pipe is formed is set to be 12 MPa or more. S2 is 0.11 Self-priming centrifugal pump apparatus characterized by being configured to set so that the upper.