JPH08285171A - Automatic pipe line pressure reducing device - Google Patents

Abstract

PURPOSE: To provide an automatic pressure reducting device which can safely reduce excessive water pressure generated in a pipe line in a pipe line network. CONSTITUTION: A connecting pipe line 2 is arranged in the middle of a pipe line, and one end is connected to the upstream side of the pipe line, and the other end is connected to the downstream side of the pipe line, respectively. A valve 3 to open and close a passage of the connecting pipe line 2 is arranged in the connecting pipe line 2. An automatic pipe waterway pressure reducing device 1 is provided with a water pressure detector 4 to detect water pressure downstream from the valve 3 inside the connecting pipe line 2 and a valve opening-closing mechanism 5 to control opening of the valve 3 so that the opening of the valve 3 becomes small when the water pressure detected by the water pressure detector 4 is high, and that the opening of the valve 3 becomes large when the water pressure detected by the water pressure detector 4 is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe water channel automatic depressurizing device for safely reducing excess water pressure generated in a pipe water channel.

[0002]

2. Description of the Related Art In recent years, in agricultural and industrial waterways, city waterworks, etc., a large number of secondary pipes are branched from the primary pipes, and a large number of peripheral pipes are branched from the respective secondary pipes. A complicated and long pipeline network is formed such that the pipeline is branched, and water is supplied to the pipeline network by a high-pressure pumping pump provided in the primary pipeline.

In such a pipe waterway network, the pressure inside the pipe changes intricately depending on the distance from the high-pressure pump discharge port and the topography, and when it overlaps with the water hammer, an abnormal high pressure state occurs and a predetermined intermediate Pressure (2-3Kg
There was a problem that the diversion valve designed to meet the requirement of / cm ² ) was often destroyed. Further, in the agricultural waterways, foreign matters such as dust are mixed in the pipe waterways, and there is a problem that the water diversion valve is broken due to clogging of the dust and water quality is easily deteriorated.

Conventionally, as one of the methods for solving this,
Arrange a surge tank with free water surface in the network of pipes,
Some control excess water pressure by exposing the free water surface to the outside. However, this method has drawbacks that it requires a huge amount of facilities, is very costly, and water management is not easy.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pipeline in a pipeline network for agricultural and industrial waterways, city waterworks, etc., which can safely reduce excess water pressure generated in the pipeline. An object is to provide an automatic decompression device. Another object of the present invention is to provide an automatic depressurizing device for pipe water channels that does not cause a failure due to clogging of dust.

[0006]

In order to solve the above-mentioned problems, according to the present invention, one end of the pipe is connected to the upstream side of the pipe and the other end is connected to the downstream of the pipe. Connection pipe line, valve means provided in the connection pipe line for opening and closing the flow path of the connection pipe line, water pressure detection means for detecting water pressure on the downstream side of the valve means inside the connection pipe line, and water pressure detection When the water pressure detected by the means is high, the opening degree of the valve means becomes small, and when the water pressure detected by the water pressure detecting means is low, the opening degree of the valve means is controlled so that the opening degree of the valve means becomes large. A pipe water channel automatic depressurizing device comprising the means is constituted.

[0007] According to a preferred embodiment of the present invention, the valve means has a housing part disposed in the middle of the connecting pipe line, a chamber is formed inside the housing part, and the housing part is inside the chamber. The upstream and downstream connecting pipe portions are respectively open, and the valve means further has a valve body arranged in the chamber of the accommodating portion, and the valve body has a valve along the axial direction of the connecting pipe. A water passage extending through the body is formed, and the water passage has a flow passage cross-sectional area that is at least equal to the flow passage cross-sectional area of the connecting pipe. In a state in which the outer surface of the valve body and the wall surface of the chamber are sealed by smoothly engaging with the wall surface, the valve opening / closing means causes the both end openings of the water passage of the valve body to respectively open the chamber inner opening of the connection pipeline portion. Fully open position that overlaps with the opening in the chamber of the connecting pipeline so as to completely include It may be allowed movement between a closed position in which both open ends of the water channel is non-overlapping with the chamber opening connecting pipeline portion.

According to another preferred embodiment of the invention, the pipe channel has a circular cross section and the chamber of the receiving part of the valve means has a cylindrical shape with a diameter larger than the diameter of the connecting line, Extending vertically, the valve body of the valve means has a cylindrical shape and is coaxially arranged in the chamber and rotatable between a fully open position and a closed position about an axis of rotation arranged along the axis of the chamber It is located in.

According to yet another preferred embodiment of the present invention, the pipe channel has a circular cross section, and the chamber of the receiving part of the valve means has a spherical shape with a diameter larger than the diameter of the connecting line.
The center of which is on the axis of the connecting conduit, the valve body of the valve means is spherical and is arranged concentrically in the chamber, around a rotation axis extending through the center of the chamber and perpendicular to the axis of the connecting conduit. Is rotatably arranged between a fully open position and a closed position.

According to yet another preferred embodiment of the invention, the water pressure detecting means comprises a piston arranged outside the connecting line, the cylinder of the piston being located downstream of the valve means in the wall of the connecting line. The piston is provided with means for connecting to the inside of the connecting pipe through the provided water passage and constantly urging the piston head in the direction of decreasing the volume of the cylinder, and the valve opening / closing means is the valve body of the valve means. A rotation shaft that extends through the wall of the housing portion, a pinion that is coaxially attached to the rotation shaft, and a rack that is formed so as to extend in the axial direction of the piston rod of the piston of the water pressure detection means and that engages with the pinion. When the piston rod moves linearly in the direction in which the cylinder volume of the water pressure detecting means increases, the valve body of the valve means rotates toward the fully open position, and the cylinder volume of the water pressure detecting means increases. When the piston rod in the direction of small to linear motion, the valve body is rotated towards the closed position.

According to still another preferred embodiment of the present invention, the collection of the Karman vortices generated by the water flow flowing through the connecting conduit portions is provided in the regions near the valve means in the upstream and downstream connecting conduit portions, respectively. A dust discharge hole is provided with a valve that captures dust by utilizing its characteristics. Also,
A dangerous pressure release hole provided with a valve is provided in the downstream pipe water passage connected to the downstream connection pipe portion.

[0012]

In the pipe water channel automatic decompression device according to the present invention, one end of the connection pipe line is connected to the upstream side of the pipe water line and the other end is connected to the downstream side of the pipe water line. Then, the water pressure detection means of the pipe water channel automatic decompression device always detects a water pressure change on the downstream side of the pipe water channel. As the water pressure on the upstream side of the pipe water passage increases, the water pressure on the downstream side rises, and when this is detected by the water pressure detecting means, the valve opening / closing means controls the valve means so that the valve opening degree of the valve means becomes smaller. As a result, the head loss due to the valve means increases, and the water pressure on the downstream side of the pipe water channel decreases. On the other hand, when the decrease in water pressure on the downstream side of the pipe water passage is detected by the water pressure detecting means, the valve opening / closing means controls the valve means so that the valve opening degree of the valve means becomes large. In this case, since the head loss due to the valve means is reduced, the water pressure on the downstream side of the pipe water channel is increased. Thus
The water pressure on the downstream side of the pipe water passage is maintained at an allowable intermediate pressure within a predetermined range without being affected by the water pressure fluctuation on the upstream side of the pipe water passage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are top sectional views showing an embodiment of an automatic depressurizing device for pipe water channels according to the present invention. FIG. 1 shows a state where a valve described later is in a closed position, and FIG. 2 shows a valve in a fully opened position. The respective states are shown in.

As shown in FIGS. 1 and 2, an automatic depressurizing device 1 for a pipe water passage according to the present invention has a cylindrical connecting pipe passage 2 having flanges 2'and 2 '' at both ends. . The connection pipeline 2 is connected from the upstream pipeline by connecting one end flange 2 ′ to the flange 30 of the upstream pipeline and the other end flange 2 ″ by a flange 31 of the downstream pipeline, respectively. A flow path is formed through the pipe line 2 to reach the downstream side pipe water passage. The connection conduit 2 is provided with a valve 3 that opens and closes the flow path of the connection conduit 2. The pipe water channel automatic decompression device 1 further includes a valve 3 inside the connection pipe line 2.
The water pressure detector 4 for detecting the water pressure on the downstream side, and the opening of the valve 3 becomes small when the water pressure detected by the water pressure detector 4 is high, and the valve 3 when the water pressure detected by the water pressure detector 4 is low. The valve opening / closing mechanism 5 is provided to control the opening of the valve 3 so that the opening of the valve becomes large.

FIG. 3 is an enlarged vertical sectional view showing the structure of the valve 3 of the pipe water channel automatic decompression device 1 shown in FIG. 1 to 3
As shown in FIG. 3, the valve 3 has a cylindrical shape with both ends having a diameter larger than the diameter of the connecting conduit 2 closed, and has a housing portion 6 extending vertically across the connecting conduit 2. A cylindrical chamber 7 is formed inside the accommodating portion 6, and inside the chamber 7,
The upstream side connecting pipe line portion 2a and the downstream side connecting pipe line portion 2b on both sides of the housing portion 6 are open.
In addition, in this embodiment, the accommodating portion has a cylindrical shape with both ends closed, but instead, the accommodating portion has a spherical shell shape having a diameter larger than the diameter of the connecting conduit, and the center thereof is the connecting conduit. It is also possible to have a configuration on the axis of.

The valve 3 further has a cylindrical valve body 8 arranged coaxially in the chamber 7. The valve body 8 can rotate around its axis with the outer surface of the valve body 8 smoothly engaging the wall surface of the chamber 7 and a seal between the outer surface of the valve body 8 and the wall surface of the chamber 7. It has such a size. When the accommodating part has a spherical shell shape, a spherical valve element is concentrically arranged in a spherical chamber formed inside the accommodating part, and the valve element is disposed around the center of the valve element. The outer surface of the chamber and the wall surface of the chamber can rotate while being sealed.

A water passage 9 extending through the valve body 8 is formed in the valve body 8 along the axial direction of the connecting conduit 2. The water passage 9 may have a cross section of any shape as long as it has a flow passage cross-sectional area at least equal to the flow passage cross-sectional area of the connection pipe passage 2. It is preferable to have a cross-section having a shape that matches the cross-sectional shape of the connecting conduit 2. In this embodiment, the water passage 9 has a cylindrical shape, and its circular cross section is formed to match the circular cross section of the connecting conduit 2.

The valve body 8 is provided by the valve opening / closing mechanism 5.
One opening 9a of the water passage 9 is connected to the upstream connecting conduit portion 2a.
The chamber inner opening 10a of the
Of the connecting conduit portions 2a and 2b so as to completely include the chamber inner opening 10b of the downstream connecting conduit portion 2b, respectively, and the both end openings 9a and 9b of the water passage 9. Connection conduit portions 2a, 2b
Is rotated between the chamber inner openings 10a, 10b and the non-overlapping closed position.

As shown in FIGS. 1 and 2, the water pressure detector 4 has a cylindrical detector body 11. The internal space of the detector body 11 is divided into two parts by the partition wall 12. A piston head 13 is disposed coaxially with one portion of the internal space of the detector body 11, and a piston rod 14 is provided on the surface of the piston head 13 opposite to the partition wall 12 from the piston head 13 to the detector body 11. In the axial direction of the detector main body 11 through a through hole 25 formed in the end wall thereof.
A cylinder formed between the partition wall 12 and the partition wall 12, and a piston including a piston head 13 and a piston rod 14 are formed. A gap is formed between the inner peripheral surface of the through hole 25 in the end wall of the detector body and the piston rod 14,
This gap functions as a ventilation hole that communicates with the outside air.

One end of a communication pipe 17 is connected to the water passage hole 16 provided in the wall of the downstream side connection pipe line portion 2b, and the other end of the communication pipe 17 is located in the vicinity of the partition wall 12 of the cylinder 15. It has an opening inside. Piston cylinder 15
Communicate with the inside of the downstream side connecting pipe line portion 2b through the communication pipe 17, the piston head 13 receives the water pressure of the downstream side connecting pipe line portion 2b, and the piston head 13 and the piston rod 14 are subject to the fluctuation of this water pressure. Is capable of reciprocating linear motion.

On the surface of the piston head 13 on the partition side, a control rod 18 is coaxially arranged from the piston head 13.
It extends through 2 to the other part of the internal space of the detector body 11. The space between the control rod 18 and the partition wall 12 is sealed, and the other part of the internal space of the detector body 11 is provided with a vent hole 26 for communicating with the outside air. The control rod 18 is allowed to move linearly in the axial direction while being sealed against the water flowing into the piston cylinder 15. The control rod 18 has a length such that the tip of the control rod 18 is located in the other part of the internal space of the detector body 11 when the piston head 13 comes into contact with the end wall surface of the detector body 11. are doing.

A first spring 19 is accommodated in the other part of the internal space of the detector main body 11, one end of the first spring 19 is fixed to an end wall of the detector main body 11, and the other end is a control rod. It is fixed to the tip of 18. The piston head 13 is constantly urged by the first spring 19 toward the partition wall 12 side. A second spring 20 is arranged around the piston rod 14 in a space on the opposite side of the cylinder 15 with the piston head 13 sandwiched inside the piston.
Is fixed to the end wall of the detector body 11, and the other end is a free end.

The piston head 13 has a central protruding portion 24 extending toward the partition wall 12 on the surface facing the partition wall 12.
And the central protruding portion 24 abuts on the partition wall 12 to allow the piston head 13 to move in the partition wall direction (cylinder 1).
5 in the direction in which the volume of the cylinder 5 decreases), and the minimum volume of the cylinder 15 is defined at this contact position.
At this time, the communication pipe 17 includes the piston head 13 and the partition wall 12.
The space is open in the cylinder 15.

The valve opening / closing mechanism 5 includes valve bodies 8 to 8 of the valve 3.
Axis 21 extending through the wall of the housing 6 along the axis of
A pinion 22 coaxially attached to the tip of the rotary shaft 21; and a rack 23 formed to extend in the axial direction at the tip of the piston rod 14 of the water pressure detector 4 and engaged with the pinion 22. are doing. When the valve body has a spherical shape, the rotation axis of the valve body extends through the center of the spherical chamber in a direction perpendicular to the axis of the connecting pipe and penetrates the wall of the housing portion. The valve opening / closing mechanism 5 interlocks with the reciprocating linear motion of the piston rod 14 of the water pressure detector 4 to reciprocally rotate the valve body 8 of the valve 3 about the axis, and the central protruding portion 24 of the piston head 13 moves. When abutting against the partition wall 12, the valve body 8 of the valve 3 assumes the fully open position, and the piston head 1
It is adapted to assume a closed position when the 3 is pressed against the second spring 20. Therefore, when the valve body 8 of the valve 3 is near the closed position, the piston head 13
Is urged by both the first and second springs 19 and 20 in the direction in which the volume of the piston cylinder 15 decreases.

The upstream and downstream connecting pipe portions 2a,
In the region near the valve in 2b, dust discharge holes 27 and 28 each having a valve are provided. These dust discharge holes 27, 28 are provided in the valve 3 by the water flow in the connecting pipe line 2.
The dust is trapped by utilizing the dust collection characteristic of the Karman vortex generated on the upstream side or the downstream side of the and is discharged to the outside. Further, a dangerous pressure release hole 29 having a valve is provided in the downstream pipe water passage connected to the downstream connection pipe portion 2b.

FIG. 4 shows a state in which the automatic depressurizing device 1 for a pipeline according to the present invention is actually applied to a pipeline network for agricultural and industrial waterways, city waterworks and the like. As shown in FIG. 4, the pipeline network includes a primary pipeline 40, a large number of secondary pipelines 41 branched from the primary pipeline 40, and water diversion from each secondary pipeline 41 (not shown). It has a large number of peripheral conduits 42 branched via valves. And
Water is supplied to the pipeline network by a high-pressure pumping pump 43 provided in the primary pipeline 40.

In the embodiment shown in FIG. 4, the automatic depressurizing device 1 for a pipe water channel according to the present invention comprises a primary pipe water channel 40 and a secondary pipe water channel 4.
It is arranged in the middle of the secondary pipe water channel 41 near the connection portion of No. 1. Then, one end of the connection pipeline 2 of the automatic pipeline water pressure reducing device 1 is on the upstream side of the secondary pipeline 41, and the other end is the secondary pipeline 41.
Are connected to the downstream side of each.

The operation of the automatic depressurizing device 1 for pipe water channels will be described below. When the pumping pump 43 is stopped in the pipeline network of FIG. 4, the piston head 13 is maintained at a position where the central protruding portion 24 of the piston head abuts on the partition wall 12 by the biasing force of the first spring 19. The valve body 8 of the valve 3 is in the fully open position. The water pressure of the primary pipe water passage 40 and the water pressure of the secondary pipe water passage 41 are both P ₁ , and the water pressure acting on the piston of the water pressure detector is also P ₁ .

When the pumping pump 43 starts to operate, the water pressure in the primary pipe water passage 40 and the water pressure in the secondary pipe water passage 41 increase by ΔP _{1 in a} short time. Then, the water pressure in the piston cylinder 15 of the water pressure detector 4 communicating with the secondary pipe water passage 41 also increases by ΔP ₁ . At this time, assuming that the cross-sectional area of the piston head 13 is AP, the piston head 13 is AP × ΔP ₁
Under the total pressure, the first spring 19 is stretched and moves toward the second spring 20. And the first
When the spring 19 of the first spring 19 is extended by Z = AP × ΔP ₁ / K ₁ (K ₁ is the spring coefficient of the first spring), the urging force of the first spring 19 and the total pressure exerted on the piston head 13 are balanced. Then, the movement of the piston head 13 is stopped. Alternatively, when ΔP ₁ is large, the piston head 13 has the second spring 20
When the first spring 19 is pressed against Z, the first spring 19 is moved so that the relationship of AP × ΔP ₁ = K ₁ Z + K ₂ Y (K ₂ is the spring coefficient of the second spring) is satisfied.
At a position where the first spring and the second spring 20 contract by Y, the urging forces of the first and second springs and the total pressure exerted on the piston head are balanced, and the movement of the piston head 13 stops.

During this time, the piston rod 14, and hence the rack 23, are also linearly displaced by the distance Z, and with this,
The valve element 8 rotates from the fully opened position to the closed position by an angle θ corresponding to the displacement amount Z and stops (see FIG. 3). Then, the opening degree of the valve 3 becomes smaller, which causes a loss. According to fluid mechanics, head loss HL, valve 3
HL = fc × (V ₁ ) ² / (2g) is obtained, where V ₁ is the average flow velocity immediately before flowing into the pipe (average flow velocity of the primary pipe water channel 40) and g is the gravitational acceleration. Where fc is a loss coefficient, where fc = (A ₁ / (c × A) −1) ² where A ₁ is the flow passage cross-sectional area of the primary pipe water channel, A is the valve opening, and c is an experimental constant. Or directly by Weisbach's experiment.

FIG. 5 is a graph showing the relationship between the rotation angle θ (valve opening) of the valve body 8 of the valve 3 from the fully open position and the head loss HL. In this graph, the secondary pipe channel 4
1 inner diameter D = 1 m, flow path cross-sectional area A ₁ = 0.785 m ² ,
The flow velocity of the upstream secondary pipe water channel was V ₁ = 2 m / s.

By reducing the opening of the valve 3 in this way, the water pressure in the secondary pipe water channel 41 is P ₂ = (P ₁ + ΔP ₁ ) -HL = (P ₁ + ΔP ₁ ) -fc × (V ₁ ) ² / (2 g) is reduced. Therefore, by selecting the opening degree of the valve 3 so that HL = ΔP ₁ , even if the water pressure rises in the primary pipe water passage 40, the water pressure in the secondary pipe water passage 41 becomes a constant value P.
Can be maintained at ₂ .

When the water pressure in the primary pipe water channel 40 decreases by ΔP ₁ , the water pressure in the secondary pipe water channel 41, and thus the water pressure in the cylinder 15 of the water pressure detector 4, also decreases by ΔP _1, and the piston head 13
Receives a total pressure of −AP × ΔP ₁ . Then, at the position where the first spring 19 contracts and the second spring 20 extends by Z = (AP × ΔP ₁ ) / (K ₁ + K ₂ ), the urging force of the first and second springs and the piston head are increased. The total pressure exerted is balanced and the movement of the piston head 13 stops. Alternatively, when ΔP ₁ is large, the piston head 13 is separated from the second spring 20 and the first spring 19 is compressed by Z = AP × ΔP ₁ / K _{1 and the} urging force of the first spring 19 is increased. The total pressure exerted on the piston head 13 is balanced and the movement of the piston head 13 stops.

During this time, the piston rod 14 and the rack 23 are also linearly displaced by the distance Z, and the displacement amount Z of the valve body 8 from the closed position to the fully open position is accordingly accompanied.
It rotates by an angle corresponding to and stops. As a result, valve 3
And the head loss is reduced by ΔHL. If the opening of the valve 3 is selected so that ΔHL = ΔP ₁ , the water pressure in the secondary pipe water passage 41 can be maintained at a constant value even if the water pressure in the primary pipe water passage 40 decreases.

Thus, based on the pressure reducing characteristic of the valve 3 (loss head-valve opening curve), the water pressure fluctuation ΔP in the primary conduit
The cross-sectional area of the piston head 13 of the water pressure detector 4 is set so that a loss head of ΔHL = ΔP _{1 with} respect to ₁ is generated.
And the spring coefficient of the second springs 19, 20;
By determining the length of the second spring 20, the diameter of the pinion 22 of the valve opening / closing mechanism 5, and the like, the water pressure of the secondary pipe water channel 41 can always be maintained at an allowable intermediate pressure within a predetermined range. it can.

As can be seen from the graph of FIG. 5, in the pipe waterway automatic pressure reducing device according to this embodiment, when the valve opening is relatively large, the rate of change of the head loss due to the change of the valve opening is small,
On the other hand, when the valve opening is relatively small, the rate of change of the head loss due to the change in the valve opening is large, which is a pressure reducing characteristic. Therefore, the piston head 13 is biased only by the first spring 19 when the valve opening is large, and the first and second springs 19, when the valve opening is small.
It is urged by 20. As a result, even if a large water pressure difference occurs between the primary pipe water channel and the secondary pipe water channel, the water pressure on the secondary pipe water channel side can be safely reduced. At this time, as shown in FIG. 6, if a plurality of notches 32 are formed at the edges of both end openings of the water passage 9 of the valve body 8,
The decompression characteristic when the valve opening is small is further improved.

Further, in the pipe water channel automatic depressurizing device according to the present invention, while the water use is stopped, the water diversion in the secondary pipe water channel 41 is stopped and the valve 3 is closed, the valve 3 should be closed.
When water leaks into the secondary pipe water passage 41 and the pressure in the secondary pipe water passage 41 rises abnormally, the dangerous pressure release hole 29 is opened to release the abnormal pressure and prevent the pipe water passage from being broken. Further, when the opening degree of the valve 3 is small, in order to prevent the valve 3 from being clogged with dust or the like, the dust discharge holes 27 and 28 are appropriately opened to discharge dust and the like to the outside.

As described above, according to the pipe water channel automatic depressurizing device of the present invention, even if the water pressure in the primary pipe water channel fluctuates, the water pressure in the secondary pipe water channel is always always in the middle of a predetermined range. Maintained at pressure. Moreover, since the dust and the like mixed in the pipe water passage is appropriately discharged to the outside, there is almost no failure due to clogging of the dust or the like.

[0039]

As described above, according to the present invention,
In a pipeline network for agricultural and industrial waterways, city waterworks, etc., it is possible to safely reduce the excess water pressure generated in the pipeline, and to provide an automatic decompression device that does not cause a failure due to clogging of dust. .

[Brief description of drawings]

FIG. 1 is a top cross-sectional view of an embodiment of an automatic depressurizing device for pipe water channels according to the present invention, showing a state in which a valve is in a closed position.

FIG. 2 is an upper sectional view showing a state in which a valve of the pipe water channel automatic depressurizing device shown in FIG. 1 is in a fully open position.

FIG. 3 is an enlarged vertical cross-sectional view showing the structure of a valve of the pipe water channel automatic decompression device shown in FIG.

FIG. 4 is a schematic top view showing a state in which the pipe water channel automatic decompression device shown in FIG. 1 is connected to an actual pipe water channel network.

5 is a graph showing the decompression characteristics of the pipe water channel automatic decompression device shown in FIG.

6 is a top cross-sectional view showing a modified example of the water passage opening of the valve of the pipe water passage automatic depressurizing device shown in FIG.

[Explanation of symbols]

 1 Pipe Water Channel Automatic Pressure Reduction Device 2 Connection Pipeline 2a, 2b Connection Pipeline Part 3 Valve 4 Water Pressure Detector 5 Valve Opening / Closing Mechanism 6 Housing 8 Valve Disc 9 Water Passage 11 Detector Main Body 12 Partition 13 Piston Head 14 Piston Rod 15 Cylinder 16 Water through hole 21 Rotating shaft 22 Pinion 23 Rack

Claims (6)

[Claims] 1. A connection conduit, which is arranged in the middle of the pipe water channel, has one end connected to the upstream side of the pipe water channel and the other end connected to the downstream side of the pipe water channel, and the connection pipe line is provided in the connection pipeline. Valve means for opening and closing the flow path of the pipeline, water pressure detection means for detecting the water pressure on the downstream side of the valve means inside the connection pipeline, and the valve when the water pressure detected by the water pressure detection means is high A valve opening / closing means for controlling the opening degree of the valve means so that the opening degree of the valve means increases when the opening degree of the means decreases and the water pressure detected by the water pressure detecting means is low. Automatic decompression device for pipes. 2. The valve means has an accommodating portion arranged in the middle of the connection conduit, a chamber is formed inside the accommodating portion, and an upstream side of the accommodating portion and a chamber are formed in the chamber. The downstream connection conduit portions are each open, and the valve means further has a valve body arranged in the chamber of the accommodating portion, and the valve body extends along the axial direction of the connection conduit. A water passage extending through the valve body is formed, the water passage has a flow passage cross-sectional area of at least equal to the flow passage cross-sectional area of the connection pipeline, the valve body, With the outer surface of the valve body smoothly engaging with the wall surface of the chamber and the outer surface of the valve body and the wall surface of the chamber being sealed, the valve opening / closing means controls the water passage of the valve body. The openings at both ends completely close the opening in the chamber of the connection conduit portion. It is moved between a fully open position in which the connecting conduit portion overlaps the chamber inner opening, and a closed position in which the both end openings of the water passage do not overlap the chamber inner opening in the connecting conduit portion. The pipe water channel automatic decompression device according to claim 1, which is obtained. 3. The pipe channel has a circular cross section, the chamber of the receiving part of the valve means has a cylindrical shape with a diameter larger than the diameter of the connection channel, and extends vertically across the connection channel. Extending, the valve body of the valve means has a cylindrical shape and is coaxially arranged in the chamber between a fully open position and a closed position about an axis of rotation arranged along an axis of the chamber. The pipe water channel automatic decompression device according to claim 2, wherein the pipe water channel automatic decompression device is rotatably arranged. 4. The pipe water channel has a circular cross section, and the chamber of the accommodating portion of the valve means has a spherical shape with a diameter larger than the diameter of the connection pipe line, the center of which is the connection pipe line. On an axis, the valve body of the valve means is spherically shaped and arranged concentrically within the chamber, and about the axis of rotation extending through the center of the chamber and perpendicular to the axis of the connecting conduit. The pipe water channel automatic decompression device according to claim 2, wherein the pipe water channel automatic decompression device is rotatably arranged between a fully open position and the closed position. 5. The water pressure detecting means has a piston arranged outside the connection conduit, and a cylinder of the piston is a water passage hole provided in a wall of the connection conduit downstream of the valve means. Is connected to the inside of the connection pipeline through the piston, and means for constantly urging the piston head of the piston in the direction in which the volume of the cylinder decreases is provided, and the valve opening / closing means is the valve body of the valve means. From the rotary shaft extending through the wall of the housing portion, a pinion coaxially attached to the rotary shaft, the piston rod of the piston of the water pressure detecting means is formed to extend in the axial direction, When the piston rod has a linear motion in a direction in which the volume of the cylinder of the water pressure detecting means increases, the valve body of the valve means has the fully open state. The valve body rotates toward the closed position when the piston rod linearly moves in a direction in which the volume of the cylinder of the water pressure detecting means decreases. Three
Alternatively, the pipe water channel automatic decompression device according to claim 4. 6. Dust is captured in the regions near the valve means in the upstream and downstream connecting pipe portions, respectively, by utilizing the dust collecting characteristics of Karman vortices generated by the water flow flowing in the connecting pipe portion. 6. A pipe water channel automatic decompression device according to any one of claims 1 to 5, further comprising a dust discharge hole provided with a valve.