JPS647372Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pressure reducing valve for liquid that is capable of maintaining good flow characteristics without causing the secondary pressure to fluctuate even if the primary pressure fluctuates to some extent. .

Conventionally, such pressure reducing valves sense the pressure on the secondary side using a diaphragm whose pressure is adjusted by a spring.
A valve linked to the displacement of the diaphragm adjusts the degree of opening and closing of the valve port, thereby maintaining the pressure on the secondary side at a constant value.

However, in a system that opens and closes the valve based on pressure fluctuations on the secondary side, as shown in Figure 4, when the primary pressure P ₁ (pump pressure) decreases as the flow rate increases, the secondary pressure P ₂ ' also decreases. It had the disadvantage of

In view of these drawbacks, the present invention divides the inside of the main body into a primary pressure chamber and a secondary pressure chamber via a partition wall, forms a lower opening in the partition wall, and provides a primary pressure chamber opposite to the lower opening. An upper opening is formed in the upper part of the main body constituting the pressure chamber, and a cylindrical body having a valve port for communicating the primary pressure chamber and the secondary pressure chamber between the lower opening and the upper opening is detachably attached. A lid body is removably attached to the upper opening, a valve stem is disposed within the cylinder body, and the lower end of the valve stem is attached to and detached from a valve seat protruding from the periphery of the valve opening. At the same time, a piston with a diameter slightly larger than the diameter of the valve body is attached to the upper end, and the piston separates the primary side pressure chamber from the lid body. A back pressure chamber is provided, and an orifice is provided through the piston to communicate the primary side pressure chamber and the back pressure chamber, and the lid body is provided with a communication passage communicating with the back pressure chamber and a drainage passage communicating with the communication passage. To provide a liquid pressure reducing valve, in which a housing is removably screwed on, and a cap body is screwed onto the housing, and a cap body is adjustably fitted with a diaphragm for opening and closing a drainage channel and a spring for urging the diaphragm to close. In order to solve the above-mentioned drawbacks, one embodiment of the present invention will be described below based on the drawings. 1 is a pressure reducing valve for liquid according to the present invention, and the main body 2 of the pressure reducing valve 1 is A primary pressure chamber 4 communicating with the inflow port 3 and a secondary pressure chamber 6 communicating with the discharge port 5 are divided by a partition wall 7, and a lower opening 8 is formed in the partition wall 7. An upper opening 9 is formed in the upper part of the main body 2 facing the upper opening 9, and a lid 11 is attached to the flange 10 around the upper opening 9 with bolts 12, 12'... to close the upper opening 9. It is crowned with

Reference numeral 18 denotes a flow rate control valve unit that is detachably installed in the main body 2, and the cylindrical body 15 is inserted between the upper opening 9 and the lower opening 8 of the main body 2 via O-rings 14, 14'. At the same time, a communication passage 16 is provided through the center of the cylindrical body 15, and the primary pressure chamber 4 and the secondary pressure chamber 6 are communicated with each other through a valve port 17 that opens at the lower end. Reference numeral 18 denotes a valve stem disposed within the cylinder body 15, and a valve port 17 is provided at the lower end of the stem.
A valve body 2 consists of a disk 20 that attaches to and separates from a valve seat 19 protruding from the periphery of the valve body 20 to open and close the valve port 17, and a tapered guide 21 that adjusts the degree of opening of the valve port 17.
A piston 24 is attached to the upper end of the valve stem 18 and has a diameter B slightly larger than the diameter A of the valve body 22.
The piston 24 separates the primary pressure chamber 4 from the back pressure chamber 25 inside the lid 11, and an orifice 26 is inserted through the piston 24. At least the primary side pressure chamber 4 and the back pressure chamber 25 are communicated through the orifice 26. Reference numeral 27 denotes a sealing member attached to the sliding portion of the piston 24, which forms a groove 28 on the outer periphery of the piston 24, and inserts an annular piston ring 30 made of fluororesin into the groove 28 via an O-ring 29. the piston ring 3 with the O-ring 29.
0 in the direction of the outer periphery.

A pilot valve unit 31 is detachably screwed onto the lid 11, and has a communication passage 32 communicating with the back pressure chamber 25 and a drainage passage 33 communicating with the communication passage 32 at one end and opening to the outside at the other end. A housing 34 having a housing 34 is removably screwed onto the upper part of the lid body 11 via an O-ring 35, and a cap is provided on one side end of the housing 34 to cover a communication opening 36 between the communication passage 32 and the drainage passage 33. The body 37 is screwed on. 38 is the housing 34 and the cap body 3
7, and a disk 40 is attached to the diaphragm 38 via a disk receiver 41, which attaches to and separates from a valve seat 39 formed at the left end of the drain channel 33 to open and close the drain channel 33. , a spring receiver 42 disposed on the left end surface of the diaphragm 38 and a spring receiver 44 disposed within the cap body 37 so as to be adjustable with an adjustment screw 43.
A spring 45 is press-fitted between the drainage channel 3 and
3 is being suppressed.

Moreover, FIG. 3 shows another embodiment, in which the primary pressure chamber 4
The secondary pressure chamber 6 is communicated with the secondary pressure chamber 6 through a bypass pipe 46.

Next, the operation of the pressure reducing valve for liquid according to the present invention will be explained. Liquid flows into the primary pressure chamber 4 from the inlet 3 by the operation of the pump. At this point, piston 2
Since the diameter B of the valve body 4 is slightly larger than the diameter A of the valve body 22, the valve body 22 is in a state in which the valve port 17 is closed.
The liquid flowing into the primary pressure chamber 4 flows into the back pressure chamber 25 and the pilot valve unit 31 via the orifice 26, and applies back pressure to the upper surface of the piston 24. This back pressure is the adjustment screw 43.
When the value exceeds the predetermined set value adjusted by The liquid is returned to the piping on the pump inlet side through 38. The back pressure acting on the upper surface of the piston 24 in the back pressure chamber 25 exceeds the secondary pressure P ₂ of the secondary pressure chamber 6 and the pressure in the valve closing direction caused by the diameter difference between the piston 24 and the valve body 22. As the piston 24 slides downward, the valve body 22 moves away from the valve seat 19 and opens the valve port 17, causing liquid to flow into the secondary pressure chamber 6 and from the discharge port 5. It is sent.
The amount of downward displacement of the valve body 22, that is, the opening degree of the valve port 17 is determined by the back pressure acting on the piston 24 and the secondary pressure chamber 6.
is determined by the differential pressure between the secondary side pressure P ₂ and the pressure in the valve closing direction caused by the diameter difference between the piston 24 and the valve body 22, and is gradually opened by the guide 21 of the valve body 22, as shown in FIG. As shown in the figure, the secondary pressure P ₂ is not affected by fluctuations in the primary pressure P ₁ and is maintained at a constant pressure.

In other embodiments, the primary pressure chamber 4
Since the secondary pressure chamber 6 and the secondary pressure chamber 6 are communicated with each other by the bypass pipe 46, when the flow rate of the fluid becomes 0, as shown by the chain line in Fig. 4, the primary pressure P ₁ and the secondary pressure
When P ₂ becomes equal pressure and the operation of the pump is controlled by a pressure switch, it is possible to easily maintain the set pressure (for example, point X) when the pump is stopped. Note that point Y indicates the set pressure for pump operation.

In short, in the present invention, the valve body 22 that controls communication between the primary pressure chamber 4 and the secondary pressure chamber 6 is opened by the differential pressure between the back pressure acting on the piston 24 and the secondary pressure P ₂ . The valve body 2 is controlled by the diameter difference between the diameter A of the valve body 22 and the diameter B of the piston 24.
2, since a slight pressure is always applied in the valve closing direction, the outlet pressure P ₂ is not affected by fluctuations in the primary pressure P ₁ and can be maintained at a constant pressure. On the other hand, the cylinder body 15, the valve stem 18,
The valve body 22 and the piston 24 are part of the flow control valve unit 1.
3, the pilot valve unit 31 can be attached and detached by removing the lid 11, and the housing 34, diaphragm 38, spring 45, and cap 37 can also be attached and detached from the lid 11 as the pilot valve unit 31, making assembly and disassembly of each member easy. It is possible to make it happen. In another embodiment, the primary pressure chamber 4 and the secondary pressure chamber 6 are communicated with each other through the bypass pipe 46, so that when the used flow rate becomes 0, the primary pressure P ₁ and the secondary pressure P ₂ are equal. This has great practical effects, such as making it easier to maintain the set pressure when the pump is stopped when the operation of the pump is controlled by a pressure switch.

[Brief description of the drawings]

The figure shows one embodiment of the present invention.
2 is a partially cutaway perspective view of a piston, FIG. 3 is a diagram showing another embodiment, and FIG. 4 is a diagram showing flow characteristics. 2... Main body, 4... Primary pressure chamber, 6... Secondary pressure chamber, 7... Partition wall, 8... Lower opening, 9...
...Top opening, 11...Lid, 15...Cylinder, 1
7... Valve port, 18... Valve stem, 22... Valve body, 24
... Piston, 25 ... Back pressure chamber, 26 ... Orifice, 32 ... Communication passage, 33 ... Drainage channel, 34 ...
...Housing, 37...Cap body, 38...Diaphragm, 45...Spring, 46...Bypass pipe.

Claims (1)

[Claims for Utility Model Registration] (1) The interior of the main body is divided into a primary pressure chamber and a secondary pressure chamber via a partition, and a lower opening is formed in the partition, and the chamber is opposed to the lower opening. An upper opening is formed in the upper part of the main body constituting the primary pressure chamber, and a cylindrical body having a valve port that communicates the primary pressure chamber and the secondary pressure chamber between the lower opening and the upper opening is attached and detached. A lid body is removably attached to the upper opening, a valve stem is disposed within the cylinder body, and a valve seat protruding from the periphery of the valve opening is attached to the lower end of the valve stem. A valve body is attached and detached to open and close the valve port, and a piston having a diameter slightly larger than the diameter of the valve body is attached to the upper end, and the piston separates the primary side pressure chamber from the inside of the lid body. A back pressure chamber is provided in the body, and an orifice is provided through the piston to communicate the primary side pressure chamber and the back pressure chamber, and the lid body has a communication passage communicating with the back pressure chamber and a drainage passage communicating with the communication passage. A housing having a drainage channel is removably screwed onto the housing, and a cap body is screwed onto the housing, which is adjustable and has a diaphragm for opening and closing the drainage channel and a spring for compressing the diaphragm to close the valve. Liquid pressure reducing valve. (2) The pressure reducing valve for liquid according to claim 1, wherein the primary pressure chamber and the secondary pressure chamber are communicated with each other by a bypass pipe.