JPS633320A - Pressure selecting device for pressure reducing valve - Google Patents

Abstract

PURPOSE:To prevent the inadvertent changeover of a selector valve by securing a gap of the prescribed dimensions between a valve rod and a coupling part. CONSTITUTION:A gap of a prescribed dimension (a) is secured at a coupling part between a slider 7 and a valve rod 58. Thus it is avoided that a switch valve 57 is immediately opened/closed when the slider 7 moves slightly up and down. As a result, the water pressure is kept stably at a low or high level at the secondary side. While the water pressure of a cylinder chamber 11 always acts on the valve 57 in the valve opening direction and therefore the inadvertent open/close of the valve 57 is avoided owing to the gap secured at the coupling part between the slider 7 and the rod 58.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a pressure switching device for a pressure reducing valve.

Conventional technology Conventionally, a valve that can be opened and closed is installed in the middle of a water supply pipeline to divide the pipeline into a primary side (supply side) and a secondary side (receiver side), and the water pressure on the secondary side is detected. There is a pressure reducing valve that maintains the water pressure on the secondary side at a predetermined water pressure by opening and closing the valve based on the detected value and adjusting the amount of water supplied from the negative side to the secondary side. Furthermore, some of these pressure reducing valves are equipped with a switching device that automatically switches the water pressure on the secondary side when the valve opens and closes. In other words, at night when the demand for water is low, the water pressure on the secondary side is maintained low to reduce the amount of water leakage on the secondary side, and during the daytime when the demand for water is high, the water pressure on the secondary side is kept low. It is designed to maintain a high water supply level and provide sufficient water supply.

A typical example of such a pressure switching device for a pressure reducing valve is the one described in Japanese Patent Publication No. 59-29887.

Problems to be Solved by the Invention In the pressure switching device described in Japanese Patent Publication No. 59-29887, switching between the low-pressure pilot device and the high-pressure pilot device cannot be performed reliably when the change in flow rate is linear. The water pressure on the secondary side is maintained at a low pressure state or a high pressure state. However, the flow rate on the secondary side is constantly changing,
In order to maintain a constant water pressure on the secondary side, which changes as the flow rate changes, the valve body of the pressure reducing valve constantly moves slightly up and down. Since the valve body that switches between the low-pressure pilot device and the high-pressure pilot device and the valve body are integrally connected, near the switching point between the low-pressure pilot device and the high-pressure pilot device, the valve body does not move in the vertical direction. Due to the slight movement, the switching valve is repeatedly opened and closed, and the water pressure on the secondary side is either low pressure due to the activation of the low pressure pilot device or high pressure due to the activation of the high pressure pilot device, making it unstable and impractical. It has the disadvantage of being undesirable. Further, due to the repeated operation of the valve in this way, there is a drawback that the life of the sealing member used in the valve is shortened.

The present invention was made in view of these points.

The purpose is to improve the pressure switching device of a pressure reducing valve that can prevent involuntary switching of the switching device due to slight movement of the valve body in the vertical direction and stabilize the water pressure on the secondary side to a low pressure state or a high pressure state. do.

Means for solving the problem A cylinder chamber, where water pressure in the valve closing direction acts on the valve body of the differential pressure reducing valve slidably held in the cylinder, and the secondary side of the differential pressure reducing valve are connected. A first communicating pipe and a second communicating pipe are provided. A low-pressure pilot device equipped with a low-pressure valve that changes its opening when the water pressure on the secondary side changes slightly from the predetermined set water pressure is installed in the middle of the second communication pipe, and the water pressure on the secondary side is set to the predetermined setting. A high-pressure pilot device equipped with a high-pressure valve whose opening degree changes when the water pressure slightly fluctuates, and a switching device equipped with a switching valve are provided in the middle of the first communication pipe. A sliding body that slides in conjunction with the sliding movement of a valve body of a differential pressure reducing valve is provided, and a valve body that slides together with the sliding body to open and close a switching valve of a switching device is connected to the sliding body. A gap of a predetermined size along the sliding direction of the sliding body is provided at the connecting portion between the sliding body and the valve body.

The water pressure on the working secondary side is maintained at a low pressure state under the control of a low pressure pilot device or at a high pressure state under the control of a high pressure Parosoto device. Maintaining the low pressure state or high pressure state of the secondary side water pressure is as follows:
When the secondary water pressure fluctuates slightly from the predetermined set water pressure, the opening of the low-pressure valve or high-pressure valve changes accordingly, and in addition, the opening of the differential pressure reducing valve changes accordingly. This is done by increasing or decreasing the amount of water supplied to the secondary side. Switching between a low pressure state and a high pressure state is performed by opening and closing a switching valve of a switching device, and when the switching valve is closed, the secondary side water pressure is in a low pressure state, and when the switching valve is open, it is in a high pressure state. The switching valve is opened and closed by the sliding movement of the valve body in conjunction with the sliding movement of the sliding body, which is linked to changes in the opening degree of the valve body. A gap of a predetermined dimension is provided, and the valve stem is slid after the sliding body has slid by a predetermined dimension or more.

Therefore, involuntary opening and closing of the switching valve due to slight fluctuations in the opening of the valve body is prevented, and the water pressure on the secondary side is stabilized at a low pressure state under the control of the low pressure pilot device or a high pressure state under the control of the high pressure pilot device. maintained.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. A differential pressure reducing valve 1 is provided in the middle of a pipe (not shown) through which water flows, and the valve box 2 includes an opening 3 on the primary side, an opening 4 on the secondary side, a valve seat 5, and the valve seat A cylinder 6 is formed above the cylinder 5, and the cylinder 6 is provided with a valve body 7 whose upper diameter is larger than the lower diameter so as to be slidable in the vertical direction. The valve box 2 also has a tapered needle 9 inserted into a nozzle 8 formed at the center of the valve body 7.
has been erected. The hollow part 10 in the valve body 7 is communicated with the primary opening 3 through the nozzle 8, and the hollow part 10 and the cylinder chamber 11 inside the cylinder 6 are formed in the valve body 7. They are communicated through a through hole 12.

Next, a high pressure pilot device 1 is attached to the lid 13 of the valve box 2.
4 and a low pressure pilot device 15 are fixed. The valve box 16 of the high pressure pilot device 14 has a communication port 18 to which one end of the pipe 17 is connected, a communication port 20 to which one end of the pipe 19 is connected, and a valve seat that communicates between these communication ports 18 and 20. 21 and a pressure receiving chamber 22 are formed. Also,
This valve box 16 houses a pressure setting spring 24 which is connected to the upper end of the spring receiver 23 and a valve body 25 which is a high pressure valve. An adjustment bolt 26 is attached to the upper end of the valve box 16, and the lower end of the adjustment bolt 26 is in contact with the spring receiver 23. The valve body 25 has a pressure receiving fitting 28 on the valve stem 27.
A bellows lam 29, a collar 30, a bellows lam 31, and a spring receiver 32 are inserted and fixed in a laminated state into this pressure-receiving metal fitting 28. These bellofram 29.31
The outer periphery of each of the body rings 33 constituting the valve box 16 is
It is held between the lower lid 34 and the upper lid 35. A detection body 36 is attached to the valve box 16. This detection body 36 includes a cylinder 37 that communicates between the belloframs 29 and 31, a detection rod 38 that rises due to an increase in the internal pressure of the cylinder 37, and a detection rod 38 that is fitted into the upper part of the cylinder 37. It consists of a transparent tube 39 surrounding a detection body 38.

Further, the low pressure pilot device 15 has the same structure as the high pressure pilot device 14, and the communication port 18 has a pipe 4.
One end of the pipe 41 is connected to the communication port 20. And these pipes 40.41
A portion of the pipe 17 constitutes a second communication pipe 41a that communicates the cylinder chamber 11 with the secondary side of the differential pressure reducing valve 1. Note that a valve body 25a, which is a low pressure valve, is housed in the valve box 16.

Next, a switching device 45 consisting of a base case 42, a display case 43, and a valve case 44 is provided in the center of the lid 13. A pressure receiving chamber 46 communicating with the inside of the cylinder 6 is formed in the base case 42, and the pipe 41 communicating with the pressure receiving chamber 46 is formed in the base case 42.
A first communication port 47 to which the other end is connected, and a second communication port 49 to which one end of the pipe 48 communicating with the pressure receiving chamber 46 is connected are formed. This pipe 48 and the pipes 19 and 17 constitute a first communication pipe 48a that communicates the cylinder chamber 11 with the secondary side of the differential pressure reducing valve 1. An inner cylinder 50 is housed within the valve case 44, and a ring-shaped first passage 51 and a second passage 52 are formed between the valve case 44 and the inner cylinder 5o.

The valve case 44 has a communication port 5 to which the other end of the pipe 48 communicating the pressure receiving chamber 46 and the passage 51 is connected.
3 is formed in the inner cylinder 50, and furthermore, a through hole 55 is formed in the inner cylinder 50, which communicates the hollow part 54 in the inner cylinder 5o with the passage 51. Further, a communication port 56 is formed in the valve case 44 to which the other end of the pipe 19 communicating the passage 52 and the pressure receiving chamber 22 of the high pressure pilot device 14 is connected. A spherical switching valve 57 that partitions the hollow portion 54 and the passage 52 is housed within the hollow portion 54 .

Next, a valve body 58 is provided that passes through the base case 42, display case 43, and valve case 44. Valve body 5
The tip of 8 faces the switching valve 57, and the valve body 58
The lower end of the valve body 7 is connected to the valve body 7 which also serves as a sliding body. At the connecting portion between the valve body 58 and the valve body 7, the valve body 5
Upper nut 58a and lower nut 58b attached to 8
A gap having a predetermined size α is provided by subtracting the plate thickness of the valve body 7 through which the valve body S8 passes from the distance between the valve body S8 and the valve body S8. A display body 60 is provided in the hollow portion 59 of the display case 43 and is connected to the valve stem 58 and moves up and down together with the valve stem 58 to display the movement of the valve body 58.

Next, the other end of the pipe 17 is connected to the secondary opening 4 of the differential pressure reducing valve 1. In addition, the pipe 4
0 is connected to the middle of the pipe 17.

In such a configuration, for example, the force of the pressure setting spring 24 of the high-pressure pilot device 14 is set to be a force opposing the water pressure of 3 kg/d, and the force of the pressure setting spring 24 of the low-pressure pilot device 15 is set to be a force opposing the water pressure of 3 kg/d.
The force of 4 is defined as the force opposing the water pressure of 1 kg/aJ. These adjustments can be made by turning the adjustment bolt 26 and setting the pressure setting spring 2.
This is done by changing the set height of 4. Here, the water pressure on the secondary side acts on the pressure receiving chamber 22 of the high pressure pilot device 14 via the pipe 17, and
40 on the pressure receiving chamber 22 of the low pressure pilot device 15.

(Maintaining the high pressure state of the secondary side water pressure) Now, when the water pressure on the secondary side is 3 kg/al, the valve body 25a of the low pressure pilot device 15 is closed, and the valve body 25 of the high pressure pilot device 14 is 3 kg/cd. The valve body 7 is opened at the opening degree necessary to maintain the valve body 7 at the opening degree necessary to maintain the flow rate. At this time, the valve body 7 has moved upward by more than a predetermined distance for switching, as shown in FIG. 4, and the switching valve 57 is pushed up by the valve rod 58 and opened.

If the water pressure on the secondary side drops to less than 3 kg/d due to a change in the amount of water used, the valve body 2 of the high pressure pilot device 14
5 is pushed down by the biasing force of the pressure setting spring 24 by an amount corresponding to the amount of decrease in the secondary side water pressure, thereby opening the valve more widely. As a result, more pressure water in the cylinder chamber 11 flows out to the secondary side, reducing the water pressure in the cylinder chamber 11, and the valve body 7 is further opened by an amount corresponding to the opening amount of the valve body 25, so that the pressure water in the cylinder chamber 11 flows out to the secondary side. The flow rate from the opening 3 to the secondary opening 4 is increased to maintain the secondary water pressure at a predetermined high pressure state 3-/d.

At this time, the valve body 25a of the low pressure pilot device 15 is still maintained in the closed state.

When the water pressure on the secondary side rises slightly above 3 kg/aJ, the valve body 25 of the high-pressure pilot device 14 moves in the valve-closing direction to reduce its opening to an amount corresponding to the water pressure on the secondary side. The water pressure in the cylinder chamber 11 increases as the water pressure escape area decreases, and the valve body 7 descends in accordance with the degree of opening of the valve body 25. By reducing the flow rate from the opening 3 to the opening 4, the secondary side Maintain water pressure at 3 kg/cJ.

(Switching the secondary side water pressure from a high pressure state to a low pressure state) When the flow rate gradually decreases, the above procedure is repeated to gradually reduce the opening degree of the valve body 7. Then, when the valve body 7 lowers the gap size α, the valve body 7 comes into contact with the lower bolt 58b, and thereafter the valve body 58 lowers together with the valve body 7. When the predetermined flow rate and the opening degree of the valve body 7 corresponding to the predetermined flow rate are reached, the switching valve 57 blocks the flow path to the high pressure pilot device 14, so that the water pressure in the cylinder chamber 11 is transferred to the second communication pipe 41a. After that, it will communicate only to the low pressure pilot device 15.

After that, the low pressure pilot device 15 functions in the same way as the high pressure pilot device 14, and the water pressure on the secondary side is 1 kg/
a (maintained at low pressure).

(Maintaining the low pressure state of the secondary water pressure) At this point, the flow rate decreases and the water pressure on the secondary side decreases to 1 kg/,
After switching to the low pressure state of ffl, the valve body 2S of the high pressure pilot device 14 and the valve body 2 of the low pressure pilot device IS
Even if the valve 5a is open, since the switching valve 57 blocks the passage to the high pressure pilot device 14, only the low pressure pilot device 15 is controlled. When the demand for water is low in this low secondary side water pressure state, the amount of water supplied to the secondary side is small and the opening degree of the valve body 7 is small. Then, the rising dimension of the valve body 7 is the gap size α at the connection part between the valve body 7 and the valve body 58.
The valve body 58 is not raised and the switching valve 57 is not opened. Therefore, a small amount of water is supplied from the negative side to the secondary side, and the water pressure on the secondary side is 1 kg/a (
maintained at low pressure.

In addition, when the water pressure on the secondary side is in a low pressure state, if there is a large demand for water, the water pressure on the secondary side decreases slightly, and the valve body 25a is pushed down to further increase the opening degree of the valve body 25a. Therefore, the amount of water escaping from the cylinder chamber 11 to the opening 4 side via the first communication pipe 41a increases, and the valve body 7 rises. Then, as the valve body 7 rises, the valve body 7
The relationship becomes larger, and the amount of water supplied to the secondary side increases. Therefore, if the water pressure on the secondary side decreases slightly due to an increase in demand for water, the amount of water supplied increases accordingly, and the water pressure on the secondary side is maintained at a low pressure state of 1 kg/aJ.

(Switching the secondary water pressure from a low pressure state to a high pressure state) Then, as the amount of water supplied to the secondary side increases, the valve body 7 rises beyond the gap dimension α at the connection part between the valve body 7 and the valve body 58. , the valve body 7 comes into contact with the upper nut 58a, and the valve stem 5°8 also rises together with the valve body 7, and the switching valve 57 is opened by the rise of the valve body 58. When the switching valve 57 opens, the water pressure in the cylinder chamber 11 is changed to the pipe 41, the communication port 20.18 of the low pressure pilot device 15, and the pipe 40.
17 to the secondary side, and the communication port 49, pipe 48, communication port 53, passage 51, through hole 55, hollow part 54
, the passage 52, the communication port 56, the pipe 19, the communication port 20°18 of the high pressure pilot device 14, and the pipe 17 to escape to the secondary side. As a result, the water pressure on the secondary side is again controlled by the high pressure pilot device 14, and the water pressure on the secondary side is maintained at a high pressure state of 3 kg/aJ as described above.

At this time, the valve body 25a of the low pressure pilot device 15 is automatically closed.

Therefore, when the demand for water is high, such as during the day, the water pressure on the secondary side is maintained at a high pressure state by controlling the high-pressure pilot device 14, and a large amount of water is supplied. If the amount is low, the water pressure on the secondary side is maintained at a low pressure state under the control of the low pressure pilot device 15, and a small amount of water is supplied. This prevents high water pressure from acting on the secondary side at night when demand is low, thus reducing water leakage on the secondary side.
The lifespan of secondary pipes, etc. is extended.

Furthermore, since a gap of a predetermined size α is provided at the connecting portion between the valve body 7 and the valve body 58, the switching valve 57 will not be opened or closed immediately when the valve body 7 moves up and down slightly.
The water pressure on the secondary side is stably maintained at a low pressure state or a high pressure state. In addition, the water pressure of the cylinder chamber 11 always acts on the switching valve 57 in the valve closing direction, and in combination with the provision of a gap of a predetermined size α at the connecting portion between the valve body 7 and the valve body 58, the switching valve 57 Unintentional opening/closing is prevented.

Next, a second embodiment of the present invention will be explained based on FIGS. 5 to 7. Incidentally, the same parts as those explained in FIGS. 1 to 4 are indicated by the same reference numerals, and the description thereof will be omitted. Opening 3 on the primary side of differential pressure reducing valve 1 having valve body 7
An orifice 59 is provided in front of the orifice 59.
One end of Vibro 0.61 is connected to the front and rear of each.

Next, a switching device 64 having a pressure receiving case 62 and a valve box 63 is provided. The inside of the pressure receiving case 62 is divided into a first partition chamber 66 and a second partition chamber 6 by a partition body 65 which is a sliding body.
7, and a switching valve 68 is provided within the valve box 63. A support shaft 69 that protrudes below the pressure case 62 is fixed to the partition body 65, and the partition body 65 is provided between the spring receiver 70 fixed to the tip of the support shaft 69 and the lower surface of the pressure case 62. Spring 71 that biases downward
is installed. A valve stem case 72 is fixed to the upper surface of the partition body 65, and a valve body 73 is fixed to the valve stem case 72.
are connected. The tip of the valve body 73 is connected to the pressure receiving case 62
The switching valve 68 protrudes into the valve box 63 through the
is facing.

In addition, at the connecting portion between the valve body 73 and the valve body case 72, the plate thickness of the valve body case 72 through which the valve body 73 penetrates is determined from the distance between the upper nut 73a and the lower nut 73b attached to the valve body 73. A gap having a predetermined dimension β is provided. The other end of the vibro 0 whose negative end is connected to the upstream side of the orifice 59 is connected to the first partition chamber 66, and the other end of the vibro 1 whose negative end is connected to the downstream side of the orifice 56 is connected to the first partition chamber 66. It is connected to a second partition 67. The inside of the valve box 63 is partitioned into a first partition chamber 74 and a second partition chamber 75 by the switching valve 68, and the first partition chamber 74 has one end connected to the differential pressure reducing valve 1. The other end of a pipe 76 connected to the cylinder chamber 11 is connected, and one end of a pipe 77 is connected to the second partition chamber 75.

Next, a high pressure pilot device 14 and a low pressure pilot device 15 are provided. These pilot devices 14
．． Pressure receiving chambers 78 and 79 are formed in each of the pressure receiving chambers 78 and 79, and the other end of a pipe 80 whose negative end is connected to the secondary side of the differential pressure reducing valve 1 is connected to these pressure receiving chambers 78 and 79. . The high-pressure pilot device 14 is provided with a valve box 82 that is in and out of communication with a valve body 81, which is a high-pressure valve that opens and closes depending on the water pressure on the secondary side of the differential pressure reducing valve 1. The other end of the pipe 77 is connected to one side of the valve box 82, and the other end of a pipe 83 whose one end is connected to the pipe 80 is connected to the other side of the valve box 82. These pipes 80 and 83 and the pipes 76 and 77 constitute a first communication pipe 83a that communicates the cylinder chamber 11 with the secondary side of the differential pressure reducing valve 1. Further, the low pressure pilot device 15 is provided with a valve box 85 that is in and out of communication with a valve body 84, which is a low pressure valve that opens and closes depending on the water pressure on the secondary side of the differential pressure reducing valve 1. box 8
The other end of a pipe 86 whose one end is connected to the inside of the cylinder 6 is connected to one side of the valve box 5, and the other end of a pipe 87 whose one end is connected to the pipe 80 is connected to the other side of the valve box 85. ing.

And these pipes 86, 87 and the pipe 80
A part of the second communication pipe 87a communicates the cylinder chamber 11 with the secondary side of the differential pressure reducing valve 1.

In such a configuration, first, the switching device 64 will be explained. The pressure difference before and after the orifice 59 is large when the flow rate of the flow passing through the orifice 59 is high.
On the other hand, if the flow velocity is slow, it is small. Therefore, when the flow rate is slow, the difference between the water pressure acting on the first partition chamber 66 and the water pressure acting on the second partition chamber 67 is small, and the partition body 65 is spring-loaded as shown in FIGS. 5 and 6. 71, it is in a state of being pulled downward. The switching valve 68 is then maintained in a closed state. As the flow rate increases, the difference between the water pressure acting on the first partition chamber 66 and the water pressure acting on the second partition chamber 67 increases, and this water pressure difference causes the partition body 65 to
It is pushed upward as shown in the figure. When the amount of upward movement exceeds the predetermined dimension β, the valve body 73 also moves upward, and the tip of the valve stem 73 pushes up the switching valve 68, opening the switching valve 68.

Here, similarly to the first embodiment, the high pressure pilot device 14
The force of the pressure setting spring 24 of the low pressure pilot device 15 is set to be a force opposing the water pressure of 3 kg/cd, and the force of the pressure setting spring 24 of the low pressure pilot device 15 is set to be a force opposing the water pressure of 1 kg/cd.

In this state, the water pressure on the secondary side acts on the pressure receiving chamber 78 of the high pressure pilot device 14 and the pressure receiving chamber 79 of the low pressure pilot device 15 via the pipe 80. Now, when the water pressure on the secondary side is 3 kg/cnf, the valve body 84 of the low pressure pilot device 15 closes, and the valve body 81 of the high pressure pilot device 14 allows a flow rate to maintain the secondary side water pressure of 3 kg/aj. It is opened at the required opening degree. In addition, at this time, the valve body 7
is moved upward by more than a predetermined dimension to supply water to the secondary side, and the flow velocity at the orifice 59 is greater than the predetermined velocity. Therefore, due to the pressure difference before and after the orifice 59, the partition body 65, the valve stem case 72, and the valve body 73
has moved upward by a predetermined distance or more, and the gate valve 68 is pushed up by the valve body 73 and opened.

When the water pressure on the secondary side decreases to less than 3 kg/d due to a change in the amount of water used, the valve body 81 of the high pressure pilot device 14 is activated by the biasing force of the pressure setting spring 24 by an amount corresponding to the amount of decrease in the water pressure on the secondary side. The valve is pushed down and opens wider. As a result, the pressure water in the cylinder chamber 11 flows out to the secondary side, the water pressure in the cylinder chamber 11 is further reduced, and the valve body 7 is further opened by an amount corresponding to the opening amount of the valve body 81. Increase the flow rate to the next side and reduce the water pressure on the second side to 3 kg/
Maintain a high pressure state of ca.

When the water pressure on the secondary side rises slightly above 3 kg/cJ,
Since the valve body 81 of the high-pressure pilot device 14 moves in the valve-closing direction and reduces its opening to an amount corresponding to the secondary side water pressure, there is less room for the water pressure in the cylinder chamber 11 to escape, and the cylinder chamber 1
1 increases, the valve body 7 descends in accordance with the opening degree of the valve body 81, and the water pressure on the secondary side is reduced by reducing the opening degree of the valve body 7 and reducing the flow rate to the secondary side. 3 kg/, :ff
Keep it at l. When the flow rate gradually decreases, the above procedure is repeated and the opening degree of the valve body 7 gradually decreases. Note that as the flow rate decreases as the opening degree decreases, the flow velocity at the orifice 59 portion decreases, the pressure difference before and after the orifice 59 gradually decreases, and the partition body 65 is gradually pulled down by the biasing force of the spring 71. When a predetermined flow rate and an opening degree of the valve body 7 corresponding to the flow rate are reached, the partition body 65 is lowered to a predetermined position, the gate valve 57 is closed, and the high pressure pilot device 1 is closed.
4, the water pressure in the cylinder chamber 11 will be communicated only to the low pressure pilot device 15 via the second communication pipe 87a, and after that, the water pressure in the cylinder chamber 11 will be communicated only to the low pressure pilot device 15.
The low pressure pilot device 15 functions similarly to the function of , and the water pressure on the secondary side is maintained at a low pressure state of 1 kg/ad.

Here, the flow rate decreases and the water pressure on the secondary side is 1 kg/c.
After switching to the low pressure state of d, the high pressure pilot device 1
4, the valve body 81 and the valve body 84 of the low pressure pilot device 15
Even if the switching valve 68 is open, the high pressure pilot device 1
Since the passage to 4 is blocked, the low pressure pilot device 15
Under the control of only

When the water pressure on the secondary side is in a low pressure state, if there is a large demand for water, the water pressure on the secondary side decreases slightly, and the valve body 84 is pushed down to further increase the opening degree of the valve body 84. Therefore, the amount of water escaping from the cylinder chamber 11 to the secondary side through the second communication pipe 87a increases, and the valve body 7 is designed to supply the amount of water corresponding to this escaping water to the cylinder chamber 11 via the spout 8. rises.

As the valve body 7 rises, the opening degree of the valve body 7 further increases,
The amount of water supplied to the secondary side increases. Therefore, if the water pressure on the secondary side decreases due to an increase in demand for water, the amount of water supplied increases, and the water pressure on the secondary side is maintained at a low pressure state of 1 kg/*. As the amount of water supplied increases, the flow velocity at the orifice 59 section also increases, the pressure difference before and after the orifice 59 gradually increases, and the amount of upward movement of the partition body 65 gradually increases.

When the amount of upward movement of the partition body 65 exceeds the predetermined dimension β, the valve body 73 also rises together, and when it rises further, the tip of the valve body 73 pushes up the switching valve 68, and the switching valve 68
is opened. As a result, the water pressure in the cylinder chamber 11 not only escapes through the valve box 85 of the low-pressure pilot device 15, but also escapes through the pipe 76, the valve box 63, the pipe 77, the valve box 85, the pipe 83, and the pipe 80 of the high-pressure pilot device 14. Even after some time, it will escape to the secondary side. Then, the water pressure on the secondary side is again controlled by the high pressure pilot device 14, and the water pressure on the secondary side is maintained at a high pressure state of 3 kg/c+J as described above.

Next, when the demand for water is low when the secondary side water pressure is in a low pressure state, the amount of water supplied to the secondary side is small and the opening degree of the valve body 7 is small. Since the pressure difference before and after the orifice 59 is small, the upward movement dimension of the partition body 65 is smaller than that of the valve body case 7.
2 and the valve body 73, the valve rod 73 is not raised and the gate valve 68 is not opened. Therefore, a small amount of water is supplied from the negative side to the secondary side, and the water pressure on the secondary side is maintained at a low pressure state of 1 kg/aJ.

Therefore, in this embodiment, as in the first embodiment, the water pressure on the secondary side is maintained at a high pressure state and a large amount of water is supplied during the daytime when the demand for water is high, and at night when the demand for water is low. In this case, the water pressure on the secondary side is maintained at a low pressure state, and a small amount of water is supplied. Furthermore, by providing a gap of a predetermined size β at the connecting portion between the valve body case 72 and the valve body 73, the gate valve 68 can be easily moved by a slight vertical movement of the partition body 65 caused by a slight vertical movement of the valve body 7. The open/close state does not change, and the water pressure on the secondary side is stably maintained at a low pressure state or a high pressure state.

In this embodiment, the switching valve 68 and the valve body 73 are separated, but the switching valve 68 and the valve body 73 are separated.
3 may be integrally connected.

In this case, the length of the valve body 70 and the length of the lower nut 73b and the upper nut 73a are adjusted so that the switching valve 65 is closed when the valve body case 72 comes into contact with the lower nut 73b and moves to the lowest position. Set the gap dimension β.

Effects of the Invention The present invention provides a gap of a predetermined size in the connecting portion between the valve body and the sliding body for opening and closing the switching valve of the switching device as described above, so that the switching valve can be operated by a slight change in the water pressure on the secondary side. It is possible to prevent involuntary switching of the switching device, thereby stabilizing the water pressure on the secondary side to a low pressure state or a high pressure state, and especially at night when the demand for water is low, the switching device may operate involuntarily. It is possible to prevent the secondary side water pressure from switching to a high pressure state due to this, thereby reducing water leakage and prolonging the life of pipes, etc.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a vertical front view, FIG. 2 is a vertical side view showing an enlarged high-pressure pilot device, and FIG. 3 is a low-pressure pilot device. 4 is a longitudinal sectional front view showing a simplified state of control by the pilot device; FIG. 4 is a longitudinal sectional front view showing a simplified state of control by the high-pressure pilot device; FIGS. They are shown in a simplified manner; Fig. 5 is a longitudinal front view, and Fig. 6 is a longitudinal sectional front view.
FIG. 7 is an enlarged longitudinal sectional front view showing the switching device when controlled by the low-pressure pilot device, and FIG. 7 is an enlarged longitudinal sectional front view showing the switching device when controlled by the high-pressure pilot device. DESCRIPTION OF SYMBOLS 1... Differential pressure type pressure reducing valve, 6... Cylinder, 7... Valve body (sliding body), 11... Cylinder chamber, 14... High pressure pilot device, 15... Low pressure pilot device, 25
... Valve body (high pressure valve), 25a... Valve body (low pressure valve),
41a... Second communication pipe, 45... Switching device, 48
a... First communication pipe, 57... Switching valve, 58... Valve body, 64... Switching device, 65... Partition body (sliding body)
, 68...Switching valve, 73...Valve body, 81...Valve body (high pressure valve), 83a...First communication pipe, 84...Valve body (low pressure valve), 87a...・Second communication pipe

Claims (1)

[Claims] Providing a differential pressure reducing valve that is slidably held in a cylinder and has a valve body whose pressure receiving area that receives water pressure acting in the valve closing direction is set wider than the pressure receiving area receiving water pressure acting in the valve opening direction, A first communication pipe and a second communication pipe are provided that communicate the cylinder chamber of the cylinder on which water pressure in the direction of sliding the valve body in the valve closing direction and the secondary side of the differential pressure reducing valve are connected. , a low-pressure pilot device equipped with a low-pressure valve whose opening degree changes when the water pressure on the secondary side slightly fluctuates from a predetermined set water pressure is provided in the middle of the second communication pipe, and the water pressure on the secondary side is A high-pressure pilot device equipped with a high-pressure valve whose opening degree changes when the water pressure slightly fluctuates from a predetermined setting water pressure, and a switching device equipped with a switching valve are provided in the middle of the second communicating pipe, A sliding body that slides in conjunction with the sliding operation is provided, a valve stem that slides together with the sliding body to open and close the switching valve is connected to the sliding body, and a connecting portion between the sliding body and the valve stem. A pressure switching device for a pressure reducing valve, characterized in that a gap of a predetermined size is provided along the sliding direction of the sliding body.