JPH0245572Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic pressure control valve.

[Prior art]

Conventional pressure control valves use the pressure difference between the fluid flowing into the valve body to operate the valve body and control the pressure on the secondary side.The inside of the valve body is divided into a primary side and a secondary side. A cylindrical liner is provided between the opening formed in the partition wall and the primary partition wall, and a plurality of ports are provided in the peripheral wall of the liner, the lower end of which is formed in a V shape, and the lower end positions of which are successively higher. A piston is fitted in a liquid-tight and slidable manner, and the port is opened and closed by sliding of the piston, and a hydraulic chamber is provided above the piston, and a pipeline communicating with the primary side and the secondary side is connected to the hydraulic chamber. This type of automatic pressure control valve has a liquid-tight hydraulic pressure chamber formed on one side of a flange formed at the upper end of the piston in order to allow the piston to slide smoothly. At the same time, an atmospheric pressure chamber communicating with the atmosphere is formed on the other side, so if the sealing performance of the piston flange deteriorates due to wear of the sealing material, the fluid in the hydraulic pressure chamber will flow into the atmospheric pressure chamber. The responsiveness of the valve operation to changes in fluid pressure may deteriorate due to leakage, and the leaked fluid may fill the atmospheric pressure chamber, impeding valve operation, and may further leak into the valve chamber where the valve box is installed. There was also a risk that water would accumulate and the valve equipment would be submerged.

In addition, the liner with the port opened is fixed in the valve box, and a piston with the length necessary to close the port is installed, so the valve device becomes large and requires many parts, making it difficult to manufacture. It was also time consuming.

In addition, since the plurality of ports opened in the liner whose lower ends are formed in a V-shape have their lower end positions raised successively to change the opening area, a difference occurs in the fluid pressure passing through each port, causing the piston to There is a risk that the valve may be displaced and come into partial sliding contact with the liner, hindering smooth valve operation and response.Furthermore, due to the port shape, the ability to finely adjust the fluid pressure in the small valve opening range is not very good, and the valve body may be displaced. Since the change in flow rate was large compared to the amount, the valve opening degree corresponding to the set pressure was passed, causing hunting and making it difficult to match the set pressure. Furthermore, if the hunting condition continued, continuous water hammer was caused within the pipeline, generating vibrations and noise, which could lead to damage to the pipeline.

[Purpose of invention]

The present invention was developed in view of the above points, and aims to reduce the size of the valve device and improve its durability.In particular, it reduces the flow rate change in the small opening range of the valve body and reduces the pressure change in the small opening range. An object of the present invention is to provide an automatic pressure control valve that accurately controls pressure by reducing hunting and water hammer that occur in a small opening range of a valve body.

[Structure of the idea]

In order to achieve the above object, the present invention has a valve body slidably provided in the opening of a partition wall that defines the inside of the valve box into a primary side and a secondary side, and the valve body is moved in response to changes in fluid pressure. In an automatic pressure control valve that is operated and controlled, the valve body has a port having a cylindrical lower end that slides in contact with the opening of the partition wall and which is narrowed in an inverted V shape, and a port that is narrowed in an inverted V shape at the top. A plurality of two types of ports, a V-shaped constricted port, are arranged alternately and at equal intervals, and the upper part of the valve body is suspended from a diaphragm defining a diaphragm chamber in the upper part of the primary valve box. The valve body is characterized in that the pressure change of the fluid on the primary side and the secondary side is transmitted to the diaphragm chamber by a pilot circuit, and the valve body is arranged so that the valve is actuated by the change in volume of the diaphragm chamber.

〔Example〕

Hereinafter, one embodiment of a diaphragm type automatic pressure control valve according to the present invention will be described based on FIGS. 1 to 3.

A diaphragm automatic pressure control valve 1 that is disposed in a fluid pipeline to control the pressure on the secondary side has an interior of a valve box 2 divided into a primary side A and a secondary side B by a partition wall 3. The lower part of a cylindrical valve body 5 that slides vertically is fitted into the opening 4 in a liquid-tight manner, and the upper part of the valve body 5 is connected to the primary side A.
It is arranged so that it is located inside.

This cylindrical valve element 5 is suspended at its upper part 5a and supported by the center of a diaphragm 7 whose peripheral edge is sandwiched by the flange part 6a of the lid 6 of the valve box 2, and moves up and down within the primary side A of the valve box 2. A diaphragm chamber 8 is formed between the lid body 6 and the lid body 6.

Further, in the lower part of the cylindrical valve body 5, as shown in FIG. 2, two types of ports 9 and 10 are arranged alternately, a deep port 9 and a shallow port 10 each having an inverted V shape. The ports 9 are provided in a sawtooth shape at three locations at equal intervals, and the top of each of the ports 9, which has a deep notch depth, has an even more acute inverted V-shaped notch 9a.
is provided to form a flow port 11 that engages with the opening 4 of the partition wall 3. These multiple flow ports 11 are
The opening area changes as the valve body 5 moves up and down, and the opening number is halved especially in the small opening range, and the opening area can be finely adjusted by the notch 9a.

The primary side A of the valve box 2 and the diaphragm chamber 8 are the first
A pilot circuit 12 communicates via a throttle valve 13, and the secondary side B and the diaphragm chamber 8 communicate via a pilot valve 15 whose opening is set to a preset pressure by a second pilot circuit 14.

To explain the operation of the automatic pressure control valve 1 configured as described above, the fluid flowing into the primary side A from the inlet is pressure-controlled as it passes through the flow port 11 below the cylindrical valve body 5. However, when the secondary pressure becomes lower than the set pressure, the pilot valve 15 opens and the flow rate flowing from the diaphragm chamber 8 to the secondary side B increases, reducing the pressure inside the diaphragm chamber 8. Due to the pressure change, the cylindrical valve body 5 is displaced upward, and the opening area of the communication port 11 is increased, and the flow rate of the fluid is increased, so that the secondary side pressure increases and approaches the set pressure.

On the other hand, when the secondary side pressure exceeds the set pressure, the pilot valve 15 contracts and the flow rate flowing out from the diaphragm chamber 8 decreases.
As fluid continues to be supplied from the primary side A, the pressure rises, increasing the pressure inside the diaphragm chamber 8. Due to this pressure change, the cylindrical valve body 5 lowers and the flow port 11
As the opening area becomes smaller and the fluid flow rate decreases, the secondary pressure decreases and approaches the set pressure. As described above, the diaphragm automatic pressure control valve 1
maintains the outlet pressure at the set pressure.

By the way, the pressure control in the small opening range of the cylindrical valve body 5 of the automatic pressure control valve 1 is also performed by the flow port 11, but the ports 9 and 10 of the cylindrical valve body 5 are connected as shown in FIG. , are each formed in an inverted V shape, and as the opening degree becomes smaller, the amount of change in the area of the flow port 11 becomes smaller with respect to the amount of displacement of the cylindrical valve body 5, so that hunting is prevented from occurring. In addition, after the port 10 with a shallow notch depth is closed, the flow port 1
The number of ports 1 has been halved and the number of ports 1 formed in port 9 has been reduced by half.
1, so the flow rate change is small, and
Since the ports 9 are arranged at equal intervals on the circumferential wall of the cylindrical valve body 5, fluid pressure acts on the cylindrical valve body 5 in a balanced manner, so that malfunctions due to inclination of the valve body do not occur.

Furthermore, just before the port 9 is completely closed, a notch 9a formed at the deepest part of the port 9
becomes the flow port 11, and the change in flow rate is even more minute, so water hammer does not occur.

FIG. 3 shows another shape of the port formed in the cylindrical valve body of the diaphragm automatic pressure control valve 1 of the above embodiment, in which the lower part of the cylindrical valve body 5 has a home base shape. port 20 and the port 20
It has the same home base shape as the one shown in FIG. It works in the same way as ports 9 and 10.

In addition, FIG. 4 shows the opening area in which the horizontal axis represents the rate of displacement of the cylindrical valve body 5 from the fully closed state, and the vertical axis represents the opening area ratio of the area of the flow port at the time of the displacement to the area when fully open. This shows area ratio curves, and each curve also shows flow characteristics. Curve A shows the case where ports 9 and 10 of this embodiment are provided;
Identical conventional inverted V-shaped port 3 shown in the figure
Compared to curve B, which shows the case where multiple zeros are formed, the change in the opening area ratio rapidly decreases from around 50% of the displacement rate of the valve body, and especially immediately before fully closing, the change in the opening area ratio becomes extremely small. There is. Curve C shows the case where the ports 20 and 21 of this embodiment are provided, and compared to curve D which shows the case where a plurality of the same conventional home base type ports 40 shown in FIG. 6 are formed, the valve size is smaller. Changes in the opening area ratio become small in the opening range, and especially immediately before fully closing, the changes in the opening area ratio become extremely small.

[Effect of idea]

As described above, the present invention alternates between two types of ports: one in which the lower end of the valve body is cut out and the top narrowed into an inverted V shape, and the other in which the top is narrowed into an even more acute inverted V shape. A plurality of valve bodies are arranged at equal intervals, and the upper part of the valve body is suspended by a diaphragm defining a diaphragm chamber in the upper part of the primary side valve box, so that pressure changes of the fluid on the primary side and the secondary side are piloted. Since the valve body is arranged so that the valve is actuated by the change in the volume of the diaphragm chamber through a circuit, the valve device can be made smaller and its durability can be improved, and the port opens in a small opening range. The number of openings is reduced by half, and the change in the opening area of the port becomes extremely small just before it is fully closed, which has the effect of preventing hunting and water hammer that tend to occur in small opening ranges.

[Brief explanation of the drawing]

Figures 1 to 3 show embodiments of the present invention; Figure 1 is a cross-sectional front view of a diaphragm type automatic pressure control valve, and Figure 2 is a cylindrical shape of the automatic pressure control valve shown in Figure 1. Figure 3 is a developed view showing the arrangement of multiple ports formed on the valve body, Figure 3 is a developed view showing the arrangement of ports of different shapes, and Figure 4 is a diagram showing the opening area ratio of the ports as the valve body is displaced. The curve diagram showing the change, and FIGS. 5 and 6 are developed views showing the conventional port shape, respectively. 1 is a diaphragm type automatic pressure control valve, 2 is a valve box, 3 is a partition wall, 4 is an opening, 5 is a cylindrical valve body, 6 is a lid body, 7 is a diaphragm, 8 is a diaphragm chamber,
9 and 10 are ports, 9a is a notch, 11 is a flow port, 12 is a first pilot circuit, 13 is a throttle valve,
14 is a second pilot circuit, 15 is a pilot valve, 20 and 21 are ports, and 21a is a notch.

Claims (1)

[Scope of utility model registration request] In an automatic pressure control valve, a valve body is slidably provided in an opening of a partition wall that defines the inside of a valve box into a primary side and a secondary side, and the valve body is operated and controlled according to changes in fluid pressure. , the valve body includes a port whose lower end of a cylindrical shape that slides into contact with the opening of the partition wall is cut out and whose top is narrowed into an inverted V shape, and a port whose top is further narrowed into an acute inverted V shape. A plurality of two types of ports are arranged alternately and at equal intervals, and the upper part of the valve body is suspended from a diaphragm defining a diaphragm chamber in the upper part of the primary side valve box, and An automatic pressure control valve characterized in that the valve body is arranged so that a change in the pressure of the fluid in the diaphragm chamber is transmitted to the diaphragm chamber by a pilot circuit, and the valve is operated by a change in the volume of the diaphragm chamber.