JPH04333713A - Controller for water pressure - Google Patents

Abstract

PURPOSE:To reduce the pressure of water in channel with floating dust in such a way as not to be abnormal pressures. CONSTITUTION:Diaphragm valves 27 are connectedly set in a tailrace 26 for franthed water stream, and a diaphragm 40 to be expanded and contracted by water pressure is attached to the (channel tailrace 26) to be controlled. A control valve 28 having a valve 52 to be connected with the diaphragm 40 is set to introduce the open air through a valve chamber 44 formed in the control valve 28 into the diaphragm chamber 34 of the valve 27 to open or close the valve 27. Since a slide part can be omitted, the function can be exactly worked without affected by dust.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pressure control device that can be used as a safety valve or a pressure reducing valve in the fields of irrigation, waterworks, etc., by reducing the pressure in waterway pipes to a constant level.

0002

[Prior Art] Conventionally, there was no suitable water pressure control device at the diversion point for agricultural water with suspended dust, so in order to obtain the required water pressure, a water tank was installed at the nearest high place or on top of a steel tower. The conventional method was to use a constant water level valve such as a so-called ball tap to reduce the pressure of the flowing water in the waterway pipe to atmospheric pressure, and then obtain the required water pressure using natural pressure. In addition, when a steel tower was not possible, a high-pressure pipe that could withstand the high pressure sent to the end of the waterway was unavoidably used. In this way, if there is no high place nearby, the only option is to build a tower or use pipes, which is extremely uneconomical.

[0003] By the way, at the water diversion point of the waterway pipe,
By installing a pressure reducing valve with specifications and standards similar to those used in hydraulic equipment, when water flowing at high pressure in a pipe is divided, the water pressure is reduced and the water pressure in the downstream pipe is kept constant. It can be done. In fact, it is fine as long as the amount of water flowing in the pipe is moderate, but if water is not used downstream at all, or if water is not needed for agricultural purposes, etc., if there is water leakage from the pressure reducing valve. Since the pipes are ruptured, a safety valve is also required to release some of the water into the atmosphere if the water pressure in the pipes becomes abnormally high.

[0004] Here, the above-mentioned pressure reducing valve and safety valve will be explained with reference to a balanced piston type valve seen in the field of hydraulics. First, the configuration of the safety valve will be explained based on FIG. 3. A safety valve 2 is provided in the middle of a pipe 1 which is connected to a pump on the upstream side and a piston etc. on the downstream side, and a piston 3 included in the safety valve 2 is attached to the inside of the pipe 1 so as to be movable forward and backward. Further, a return pipe 4 is opened on the inner peripheral surface of the pipe 1 on the advancing side of the piston 3, and a valve seat 5 is formed. Further, a secondary pressure chamber 6 for accommodating oil is formed behind the piston 3, and a spring 7 is installed in a recess formed at the rear of the piston 3. Normally, the tip of the piston 3 is pressed against the valve seat 5 by the spring 7 and the hydraulic pressure of the secondary pressure chamber 6. The secondary pressure chamber 6 and the interior of the downstream side of the pipe 1 are communicated by a choke 8 consisting of a small diameter hole bored in the piston 3. Further, the inside of the secondary pressure chamber 6 is communicated with the inside of the return pipe 4 through a needle valve 10 pressed by the force of a spring 9 and a drain hole 11 passing through the piston 3. Next, the operation of the safety valve 2 will be explained. When the hydraulic pressure on the downstream side of the pipe 1 becomes higher than a predetermined pressure, the needle valve 10 is pushed by the hydraulic pressure and the spring 9
shrinks, and the oil in the secondary pressure chamber 6 is returned to the tank through the drain hole 11 and the return pipe 4. Also, since the choke 8 has a small diameter, the pressure in the secondary pressure chamber 6 decreases. , the piston 3 is pushed up by the hydraulic pressure, and its tip is separated from the valve seat 5, and a part of the oil on the upstream side of the pipe 1 is returned to the tank through the return pipe 4, and the oil is returned to the upstream and downstream sides of the pipe 1. The oil pressure decreases and becomes normal.

Next, the structure of the pressure reducing valve will be explained with reference to FIG. A pressure reducing valve 1 is installed at the connection between the primary pipe 12 and the secondary pipe 13.
4, and a piston 15 is slidably attached thereto. The piston 15 has an intermediate outer peripheral portion cut to form a flow passage 16 therein, and a spring 17 is housed therein. Further, a valve portion 18 is formed on the outer periphery of the tip portion of the piston 15, and a small diameter choke 19 that communicates with the secondary pipe 13 and the flow path 16 is formed. Then, the diameter of the flow path from the primary pipe 12 to the secondary pipe 13 is expanded or contracted by the valve portion 18 . The flow path 16 communicates with a secondary pressure chamber 20 provided on the left side of the piston 15 in the figure, and the secondary pressure chamber 20 communicates with a return pipe 22 via a drain hole 21. A needle valve 23 is disposed at the outlet of this secondary pressure chamber 20 and is pressed closed by the force of a spring 24. Next, the operation of the pressure reducing valve 14 will be explained. When the pressure inside the secondary pipe 13 becomes higher than a predetermined value, the needle valve 23 is pushed by the oil pressure, the spring 24 contracts, and the oil in the secondary pressure chamber 20 flows out into the return pipe 22 through the drain hole 21. In addition, since the choke 19 has a small diameter, the pressure in the secondary pressure chamber 20 decreases, and the piston 15 is pushed to the left in the figure by hydraulic pressure, squeezing the gap between the valve part 18 and the primary pipe 12 and reducing the flow rate. decreases, and the pressure inside the secondary pipe 13 decreases and returns to normal. Note that the spring 17 is for preventing the position of the piston 15 from becoming unstable.

[0006]

[Problems to be Solved by the Invention] As mentioned above, simplification is expected if pressure reducing valves and safety valves used in oil systems are used. However, there is dust floating in agricultural water, etc., and even if you simply try to use a conventional pressure reducing valve and safety valve, it is fully expected that dust will get caught in the gap between the sliding parts of the piston, so it is not practical. I was in trouble.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water pressure control valve that can reduce the pressure of agricultural water or the like mixed with dust.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a diaphragm valve which is opened and closed by expansion and contraction of a diaphragm chamber and is connected to the end of a water discharge pipe branched from the main stream to be controlled. A water pressure detection device having a diaphragm wall is provided in the waterway, a control valve having a valve chamber for communicating with the atmosphere or a water discharge pipe is provided, the valve chamber and the diaphragm chamber are communicated, and the valve body of the control valve is provided. and the diaphragm are linked together.

[0009] Depending on the purpose, a diaphragm valve that opens and closes depending on the expansion and contraction of the diaphragm chamber is connected to the end of the water distribution pipe branched from the main stream, and the periphery of the diaphragm valve is sealed to control the waterway to be controlled. a water pressure detection device having a wall surface of a diaphragm in communication with the waterway, a control valve having a valve chamber for communicating with the water distribution pipe or the waterway, and communicating the valve chamber with the diaphragm chamber; The control valve is characterized in that the valve body of the control valve and the diaphragm are linked.

0010

[Operation] First, when a water pressure detection device is provided on a water discharge pipe as a waterway to be controlled, the diaphragm expands due to an increase in water pressure. As a result, the valve body moves and the diaphragm chamber communicates with the atmosphere, and the diaphragm valve opens to reduce the pressure in the waterway. When the condition becomes sufficiently normal, the diaphragm contracts and the valve body returns to its original position. Furthermore, when a water flow is obtained from a water distribution pipe through a diaphragm valve, similarly, when the diaphragm expands due to an increase in water pressure, the water pressure of the water distribution pipe is introduced into the diaphragm chamber via the valve chamber. Here, due to the expansion of the diaphragm chamber, the opening of the diaphragm valve is narrowed to prevent high pressure from being transmitted to the waterway.

[0011] Next, regarding the diaphragm valve, which is commonly constructed, there is no sliding part, so there is no chance of dust getting caught. Even if dust gets caught between the valve element and the valve seat of the diaphragm valve, as the amount of water used increases thereafter, the dust will be released when the valve element opens. Furthermore, by widening the width of the valve chamber that accommodates the valve body of the control valve, there is no possibility of dust getting caught on the sides of the valve body. Also, it is possible for dust to get caught between the valve body and the valve seat, but even if it does, it will be released once the valve body is separated. It goes without saying that the diaphragm is not disturbed by dust. Additionally, since the position of the diaphragm reacts extremely sensitively to changes in water pressure, there is a risk that the control valve and diaphragm valve may open and close constantly, but the weight of the connecting rod should be supported by a spring with an appropriate spring constant. This prevents the diaphragm valve from opening and closing meaninglessly. Incidentally, since it is common practice to install a strainer at the supply port of a water discharge pipe or a water distribution pipe, large debris in the side stream can be removed.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Note that, as described above, the water pressure control device is intended for pressure reducing valves, but also for similar safety valves. First, the safety valve, which is relatively easy to explain, will be explained. As shown in FIG. 1, a water discharge pipe 26 branches off from a water pipe 25 through which agricultural water, etc. flows, and a diaphragm valve 27 and a control valve 2
8 safety valves 29 are connected in series.

The tip of the water discharge pipe 26 is opened to form a valve seat 30 of a diaphragm valve 27, and a control valve 28 is installed above the valve seat 30.
A frame body 32 having an approximately truncated conical shape with an open water pipe 31 communicating with the frame body 32 is installed, and a diaphragm 33 is stretched around the lower outer periphery of the frame body 32 to form a diaphragm chamber 34. A valve body 35 is fixed horizontally to the lower surface of the diaphragm 33, and a cap 36 made of a part of a spheroid whose diameter in the horizontal direction is approximately equal to the inner diameter of the water discharge pipe 26 is fixed to the lower part of the valve body 35. ing.

A water supply pipe 37 communicating with the control valve 28 is connected to the peripheral wall of the water discharge pipe 26, and the opening thereof is enlarged in diameter and a strainer 38 is disposed therein. Further, the inside of the water pressure detection device 41 , which has a diaphragm 40 stretched over a water pressure detection tank 39 opened at the top, is communicated with the inside of the water discharge pipe 26 via a water pressure detection pipe 42 .

The control valve 28 is provided above the water pressure detection device 41, with an upper valve cylinder 43, a valve chamber 44, and a lower valve cylinder 45 connected in the vertical direction, and an upper valve seat 46 and a lower valve seat 47 at the connecting part. It is formed. In addition, the upper valve cylinder 43 is connected to the water supply pipe 3.
7, the inside of the wide valve chamber 44 is connected to the inside of the diaphragm chamber 34 via the water pipe 31, and the lower valve cylinder 45 is connected to a drain pipe 48 that opens into the atmosphere nearby. There is. Further, a connecting rod 49 passes through the upper valve cylinder 43 and the lower valve cylinder 45 and protrudes upward and downward into the air, and a water pressure adjustment handle 50 is fitted with a screw near the upper end of the connecting rod 49. A spring 51 is interposed therebetween, and a diaphragm 40 is fixed to the lower end of the connecting rod 49. and,
A valve body 52 is fixed to a connecting rod 49 and built into the valve chamber 44, and an upper packing 53 and a lower packing 5 are installed near the ends of the upper valve cylinder 43 and lower valve cylinder 45 of the connecting rod 49, respectively.
4 is fixed and made watertight.

Furthermore, the heights of the valve chamber 44, upper valve seat 46, and lower valve seat 47 are sufficiently small so that the movement of the valve body 52 and diaphragm 40 is as small as possible when the diaphragm valve 27 opens and closes. On the other hand, the width is made sufficiently large to prevent the valve body 52 from sliding and increasing its resistance, or to prevent dust from getting caught on its sides. Further, the spring constant of the spring 51 is suitably adjusted in consideration of both that the difference in water pressure between the start and end of the operation of the diaphragm valve 27 is as small as possible, and that the number of repeated opening and closing operations is as small as possible. Also, the weight of the connecting rod 49 is the weight of the spring 5
The load is placed on 1.

Next, the operation will be explained. When the water pressure in the water discharge pipe 26 is lower than a predetermined value, the diaphragm 40 of the water pressure detection device 41 is deflated, so the valve body 52 of the control valve 28 is pressed against the lower valve seat 47, and the diaphragm 33 of the diaphragm valve 27 is compressed. is inflated, and the valve body 35 is pressed against the valve seat 30 at the opening of the water discharge pipe 26. therefore,
There is no water discharge from the water discharge pipe 26 and no drainage from the drain pipe 48. Further, the downward load of the connecting rod 49 applied to the diaphragm 40 of the water pressure detection device 41 can be adjusted by the water pressure adjustment handle 50 of the control valve 28 . Furthermore, it goes without saying that the resistance of the diaphragm 40 to changes in water pressure is small. Note that, as described above, since the valve body 52 of the control valve 28 does not slide, the resistance of the valve body 52 is also small. Furthermore, the movement of the valve body 52 is also reduced. The amount of water used downstream of the water pipe 25 decreases, and the amount of water used downstream of the water pipe 25 decreases.
6 becomes slightly higher than a predetermined value, the diaphragm 40 of the water pressure detection device 41 expands, the connecting rod 49 of the control valve 28 is pushed up, the valve element 52 approaches the upper valve seat 46, and the valve chamber 44 The entrance to the valve chamber 44 is squeezed, the amount of water flowing into the valve chamber 44 from the water discharge pipe 26 decreases, and the water pressure within the valve chamber 44 decreases. Therefore, the water in the diaphragm chamber 34 of the diaphragm valve 27 is discharged and the diaphragm 33 deflates.
The valve body 35 is pushed up and raised by the water pressure in the water discharge pipe 26, the water in the water discharge pipe 26 is discharged into the atmosphere, and the water pressure in the water discharge pipe 26 decreases.

When the diaphragm valve 27 opens slightly and the water pressure in the water discharge pipe 26 becomes normal, the water pressure detection device 4
1 diaphragm 40 deflates, and the connecting rod 4 of the control valve 28
9 and the valve body 52 are lowered, and the water pressure in the valve chamber 44 increases, so that the outflow from the diaphragm chamber 34 of the diaphragm valve 27 is stopped, the valve body 35 remains stationary, and water continues to be discharged. However, it goes without saying that when the amount of water used downstream of the water pipe 25 increases again and the water pressure in the water discharge pipe 26 falls below a predetermined level, the diaphragm 40 of the water pressure detection device 41 deflates and the diaphragm valve 27 closes. In addition, by selecting the spring constant of the spring 51 of the control valve 28, the water discharge pipe 2
Even if the water pressure in the valve 6 constantly fluctuates, the water pressure fluctuations will not be left unattended, and on the other hand, the diaphragm valve 27 will not be opened and closed incessantly in response to it too sensitively.

Next, the function of the cap 36 of the diaphragm valve 27 will be explained. If the diaphragm valve 27 suddenly closes, water hammer will occur within the water supply pipe 25 and the water discharge pipe 26, causing the water pressure to rise abnormally and potentially destroying the pipes. When closing manually, in order to prevent water hammer, it is necessary and possible to slow down the closing speed sufficiently after the closing state approaches the fully closed state. However, on the other hand, it goes without saying that it is necessary to respond to changes in water pressure as quickly as possible. Therefore, in order to satisfy the above two requirements, it is necessary to make the descending speed of the valve body 35 fast at the beginning and slow at the end, but the mechanism for controlling the descending speed in this way is extremely complicated. Therefore, in the present invention, a cap 36 is provided instead of controlling the descending speed. Since the horizontal cross-sectional area of the cap 36 increases at a higher rate at the lower part and smaller at the upper part, the cap 36 closes very slowly at the end of the operation.
Water hammer can be prevented without even controlling the descending speed.

Next, the structure of the pressure reducing valve will be explained. Only the differences from the above-mentioned safety valve 29 in terms of structure and operation will be explained. As shown in FIG. 2, the pressure reducing valve 55 is provided in a water distribution pipe 57 branched from a high-pressure main pipe waterway 56, and a water supply pipe 25 for water supply is disposed therein. The diaphragm valve 27 has the same structure, but is surrounded by a water diversion tank 58 including the valve seat 30 of the water distribution pipe 57. A water pipe 25 is connected to this water division tank 58. In addition, the water pressure detection pipe 42 of the water pressure detection device 41 is connected to the pressure reducing valve 5.
It opens into a water diversion tank 58 on the downstream side of 5.

Furthermore, in the case of the safety valve 29 described above, the water pressure on the upstream side is controlled, whereas in the case of the pressure reducing valve 55, the water pressure on the downstream side is controlled. The opposite is true. Therefore, the water supply pipe 37 is connected not to the upper valve cylinder 43 of the control valve 28 but to the lower valve cylinder 45,
The drain pipe 48 is attached to the upper valve cylinder 43 and the other end is connected to a water diversion tank 58.

Next, the function of the pressure reducing valve will be explained. If the amount of water used downstream of the water pipe 25 decreases and the water pressure in the water diversion tank 58 becomes slightly excessive, the water pressure detection device 41
The diaphragm 40 expands and pushes the connecting rod 49 upward. As a result, when the valve body 52 of the control valve 28 rises and approaches the upper valve seat 46, the outlet of the valve chamber 44 is squeezed, and the water pressure within the valve chamber 44 increases. And diaphragm valve 2
Water flows into the diaphragm chamber 34 of No. 7, the valve element 35 descends and approaches the valve seat 30, the amount of water flowing into the water diversion tank 58 decreases, and the water pressure therein decreases. However, if the water pressure in the water diversion tank 58 decreases from a high pressure state during the above-mentioned closing operation depending on the usage situation downstream, the diaphragm 40 deflates and the valve body 52 descends, causing the pressure in the valve chamber 44 to drop. Since the water pressure decreases, the water pressure in the water diversion tank 58 becomes normal, and the diaphragm valve 27 remains stationary and the flow rate becomes constant.

Furthermore, if the amount of water used downstream of the water pipe 25 increases and the water pressure in the water diversion tank 58 slightly decreases from normal, the diaphragm 40 of the water pressure detection device 41 will deflate and the valve body of the control valve 28 will collapse. 52 descends. Then, the entrance of the lower valve seat 47 is squeezed and the water pressure inside the valve chamber 44 decreases, and the water inside the diaphragm chamber 34 of the diaphragm valve 27 flows out, causing the diaphragm 33 to deflate, and due to the water pressure inside the water distribution pipe 57. The valve body 35 is pushed up, the diaphragm valve 27 is opened, the amount of water flowing into the water diversion tank 58 increases, and the pressure returns to normal. Of course, when the water pressure returns to normal, the diaphragm valve 27 remains stationary. Further, since the diaphragm valve 27 is housed in the water division tank 58 and high water pressure is applied to the valve body 35 from below, the water pressure in the diaphragm chamber 34 is always higher than that in the water division tank 58. Therefore, the water that is no longer needed when the diaphragm valve 27 opens is drained from the drain pipe 48.
It passes through and is collected into the water diversion tank 58.

[0024]

[Effects of the Invention] As mentioned above, the pressure reducing valve according to the present invention is strong against floating debris in water and has high reliability, so there is no need to take the trouble of installing a water tank at a high place or using high pressure pipes as in the past. This makes it possible to directly divert water from the high-pressure main pipe waterway. Further, since the device according to the present invention is also suitable as a safety valve, by providing a safety valve downstream of the pressure reducing valve, it is possible to ensure the safety of the water pipe even if water leaks from the pressure reducing valve. Therefore, the water pressure control device of the present invention is easy to install and costs are reduced.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a water pressure control device as a safety valve according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a water pressure control device as a pressure reducing valve according to an embodiment of the present invention.

FIG. 3 is a side sectional view showing a conventional safety valve.

FIG. 4 is a side sectional view showing a conventional pressure reducing valve.

[Explanation of sign]

25...Waterway 26...Water pipe 27...Diaphragm valve 28...Control valve 34...Diaphragm chamber 40...Diaphragm 41...Water pressure detection device 44...Valve chamber 52... Valve body 56...Diversion pipe

Claims (2)

[Claims] Claim 1: A diaphragm valve that opens and closes according to the expansion and contraction of a diaphragm chamber is connected to the end of a water discharge pipe branched from the main stream, and a water pressure detection device having a diaphragm wall is installed in the waterway to be controlled, A water pressure control characterized in that a control valve having a valve chamber for communication with a water discharge pipe is disposed, the valve chamber and a diaphragm chamber are communicated, and a valve body of the control valve and the diaphragm are linked. Device. 2. A diaphragm valve that opens and closes according to the expansion and contraction of a diaphragm chamber is connected to the end of the water distribution pipe branched from the main stream, and the diaphragm valve is sealed and communicated with the water channel to be controlled. A water pressure detection device having a diaphragm wall is provided in the waterway, a control valve having a valve chamber for communicating with the water distribution pipe or the waterway is provided, the valve chamber and the diaphragm chamber are communicated, and the valve of the control valve is provided. A water pressure control device characterized in that a body and the diaphragm are linked.