JP2012211619A - Water supply control valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water supply control valve device, in which a large differential pressure does not act on an outer seal of a differential pressure sensor at a constant differential pressure valve while a main valve is closed, while leakage of water from the main valve to the secondary side flow path caused by leaking at the seal can be prevented and an inexpensive diaphragm not including a foundation cloth can be used as the seal of the differential pressure sensor.SOLUTION: A pilot type water supply control valve 16 is added with: a valve body 54 with a differential sensor 56 which receives pressure P4 of a back pressure chamber at one side and receives pressure P2 at a primary side of a primary side flow path 30 on the other side surface at the opposite side; and a constant differential pressure valve 18 having a coil spring 68 exerting an added force to the working direction of the pressure P4 of the back pressure chamber to the valve body 54 and making the differential pressure of the pressure P4 of the back pressure chamber and the pressure P2 at the primary side constant by changing throttle to a flow path 14 by a throttle part 60 provided at the valve body 54. In this manner, the differential pressure between the primary side flow path 30 and the secondary side flow path 32 on a water supply control valve device 10 is maintained constant.

Description

  The present invention relates to a water supply control valve device obtained by adding a constant differential pressure valve to a pilot-type water supply control valve.

  Conventionally, (a) a main valve provided in the flow path, (b) a back pressure chamber in which the internal pressure acts on the main valve as a pressing force in the valve closing direction, and (c) a primary side flow with respect to the main valve Introducing small holes to increase the pressure of the back pressure chamber by introducing the water of the passage into the back pressure chamber, and (d) removing the water of the back pressure chamber into the secondary flow path to the main valve to reduce the pressure of the back pressure chamber. A pilot-type water supply control valve comprising: a pilot flow path to be reduced; and (e) a pilot valve that controls the operation of the main valve by controlling the flow of water flowing out from the back pressure chamber through the pilot flow path. A water supply control valve device is known which is provided with a constant differential pressure valve that maintains a constant differential pressure between the pressure in the secondary flow path and the pressure in the secondary flow path.

  In this water supply control valve device, the constant differential pressure valve keeps the differential pressure between the pressure of the primary flow path and the pressure of the secondary flow path constant so that the flow rate of the water supply, that is, the water flowing through the main valve The flow rate of the main valve can be made constant according to the opening of the main valve. The main valve can be closed, and water hammer can be effectively reduced.

FIG. 7 shows an example belonging to this type of water supply control valve device as a comparative example.
In the figure, reference numeral 200 denotes a body of the water supply control valve device 202, which has a flow path 204 therein.
Reference numeral 206 denotes a pilot-type water supply control valve (hereinafter simply referred to as a water supply control valve), which includes a main valve 208 formed of a diaphragm valve, a back pressure chamber 210, and an introduction small hole 214 provided through the main valve 208. A pilot flow path 218 provided through the main valve 208 and a pilot valve 220 are provided.

Here, the back pressure chamber 210 causes the internal pressure to act on the main valve 208 as a pressing force in the valve closing direction. Further, the introduction small hole 214 introduces water in the primary side flow path 212 with respect to the main valve 208 into the back pressure chamber 210 and increases the pressure in the back pressure chamber 210.
On the other hand, the pilot flow path 218 draws the water in the back pressure chamber 210 to the secondary side flow path 216 with respect to the main valve 208 to reduce the pressure in the back pressure chamber 210.
The pilot valve 220 controls the operation of the main valve 208 by controlling the flow of water that flows from the back pressure chamber 210 through the pilot flow path 218 to the secondary flow path 216.

An electromagnetic coil 222 generates an electromagnetic force when energized. The pilot valve 220 is lifted upward by the electromagnetic coil 222 and opened.
A spring 224 biases the pilot valve 220 downward in the figure, and the pilot valve 220 is held in a closed state by the spring 224.

Here, the water supply control valve 206 is an open / close valve that switches the flow path from open to closed or vice versa, with the main valve 208 being held in either the fully open position or the fully closed position.
In the water supply control valve 206, the pilot valve 220 protrudes downward to the full stroke and closes, so that the main valve 208 is fully closed and the flow path is closed.
On the other hand, when the pilot valve 220 is opened by the electromagnetic force generated by the electromagnetic coil 222, the main valve 208 is fully opened, and the flow path is switched from closed to open.

In the water supply control valve 206 configured as an on-off valve, the main valve 208 is fully opened when the pilot valve 220 moves backward to the full stroke. At this time, a large gap S is formed between the main valve 208 and the pilot valve 220. Arise. This gap S is a large gap that makes the back pressure chamber pressure P ₄ of the back pressure chamber 210 substantially the same as the secondary pressure P _{3 of the} secondary channel 216.

226 includes a primary pressure _{P 2} of the primary flow path 212 against the main valve 208, the differential pressure between the secondary pressure _{P 3} of the secondary-side flow path 216 at constant differential pressure valve to maintain a constant, the 228 It is the valve body that makes its subject.
The valve body 228, the second one side receives the primary pressure P ₂ of the primary flow path 212 in (in the figure the upper surface), opposite to the other surface in (in FIG lower surface) secondary flow path 216 subject to the following side pressure P _3, which primary pressure P ₂ and the diaphragm-type differential pressure sensing section 230 that senses the differential pressure between the secondary pressure P _3, the primary flow path from the inlet channel 232 And a restrictor 234 for restricting the flow path to 212.
The urging force of the coil spring (biasing member) 236 with respect to the valve body 228, are caused to act in the same direction as the direction of action of the secondary side pressure P _3.

但し式（１）中、Ｑは流量で、ａは主弁２０８を水が通過する際の流路面積、ｃは定数で、ΔＰは１次側圧力Ｐ_２と２次側圧力Ｐ_３との差圧，ρは水の比重である。
而してこの給水制御弁装置２０２にあっては、差圧ΔＰが一定に保たれるため、主弁２０８を通過して流れる水の流量は、主弁２０８の開度に応じた一定流量となる。
尚この種の給水制御弁装置については特許文献１に開示されている。 The constant differential pressure valve 226 by changing the aperture for the flow path by the diaphragm 234, mutually opposite forces acting on the differential pressure sensing portion 230, i.e. the force by the primary side pressure P ₂ exerted downward in the drawing , the differential pressure between the operation and the primary side pressure Te than P ₂ and the secondary side pressure P ₃ to balance the biasing force of and the coil spring 236 forces, by the secondary side pressure P ₃ acting upward in FIG. Is kept constant.
At this time, the flow rate of water flowing through the main valve 208 is given by the following equation (1).

However in the formula (1), Q is a flow rate, a is the flow passage area when passing through the main valve 208 is water, c is a constant, [Delta] P is the primary pressure P ₂ and the secondary side pressure P ₃ The differential pressure, ρ, is the specific gravity of water.
Thus, in this water supply control valve device 202, since the differential pressure ΔP is kept constant, the flow rate of water flowing through the main valve 208 is a constant flow rate corresponding to the opening of the main valve 208. Become.
This type of water supply control valve device is disclosed in Patent Document 1.

However if the water supply control valve 202, there was constructed as a differential pressure sensing section 230 of the constant differential pressure valve 226 is operated by directly sensing the differential pressure of the primary pressure P ₂ and the secondary side pressure P ₃ Therefore, when the main valve 208 is closed, the differential pressure sensing unit 230 has an inlet pressure P ₁ of the inlet channel 232 (P ₂ = P ₁ when the main valve 208 is closed) and 2 differential pressure between the next side pressure P ₃ so that the joins.
Since this differential pressure is a large differential pressure, there is a risk of leakage at the outer peripheral seal portion of the differential pressure sensing portion 230.

  Although this leakage problem may occur even when sealing is performed with an O-ring or the like, it is desirable to use a diaphragm membrane as the sealing portion in order to reduce the sliding resistance during operation of the differential pressure sensing portion 230. When a diaphragm film is used as the seal part, the film breaks due to insufficient pressure resistance of the seal part, and more specifically, the above leakage due to the break of the flexible part that curves downward in the figure and expands into a U-shaped section. This problem is particularly likely to occur.

When leakage occurs in the seal portion of the differential pressure sensing portion 230 in this manner, water leaks into the secondary side flow path 216 even though the main valve 208 is closed.
When a diaphragm membrane is used as a seal portion, it is necessary to use a diaphragm membrane with a base fabric in order to provide pressure resistance in order to prevent leakage, and in this case, the cost for the diaphragm membrane increases. End up.

Incidentally, as a prior art related to the present invention, in Patent Document 2 below, in a pilot type solenoid valve using a diaphragm, when a water hammer occurs in the flow path, the diaphragm type main valve is momentarily pushed up by the pressure. In order to solve this problem, a membrane body is disposed on the primary flow path of the diaphragm main valve, and the primary body is disposed on one surface of the membrane body. While pressure is applied, the pressure of the pilot pressure chamber (back pressure chamber) is applied to the other surface, so that when the pressure rises due to the water hammer, the pressure of the pilot pressure chamber also rises through the membrane. By doing so, it is disclosed that the main valve is prevented from being inadvertently opened.
However, in the thing disclosed in this Patent Document 2, the film body does not have a throttle part that changes the throttle with respect to the flow path, and does not function as a constant differential pressure valve, and is different from the present invention. .

JP 2009-24780 A Japanese Utility Model Publication No. 7-4974

  In the background of the above situation, the present invention prevents a large differential pressure from acting on the seal portion of the differential pressure sensing portion of the constant differential pressure valve under the closed state of the main valve, thereby preventing the occurrence of leakage at the seal portion. If there is a leak, water will not leak into the secondary flow path of the main valve, and if a diaphragm membrane is used as the seal for the differential pressure sensing part, It is an object of the present invention to provide a water supply control valve device that can suppress the required cost at a low cost without using an expensive diaphragm membrane.

  Thus, the present invention comprises (a) (a) a main valve provided in the flow path, and (b) a back pressure chamber in which the internal pressure acts on the main valve as a pressing force in the valve closing direction. (C) an introduction small hole for introducing water in the primary side flow path with respect to the main valve into the back pressure chamber to increase the pressure in the back pressure chamber; and (d) water in the back pressure chamber. (E) controlling the flow of water flowing out from the back pressure chamber through the pilot flow path to the main flow path by reducing the pressure in the back pressure chamber through the secondary flow path to the main valve; A pilot-type water supply control valve having a pilot valve for controlling the operation of the valve; (b) (f) receiving pressure of the back pressure chamber on one side and the primary side on the other side A valve body having a differential pressure sensing portion that receives a primary pressure of the flow path and senses a differential pressure between the primary pressure and the back pressure chamber pressure; and (g) the back pressure against the valve body. The urging force is applied in the direction of the chamber pressure. And the back pressure chamber pressure and the primary side pressure can be changed by changing the throttle with respect to the flow path by the throttle part provided in the valve body under the open state of the main valve. By adding a constant differential pressure valve that makes the differential pressure constant, the differential pressure between the primary side flow path and the secondary side flow path is kept constant.

  According to a second aspect of the present invention, in the water supply control valve according to the first aspect, the main valve receives the pressure of the back pressure chamber on one side and the other side of the primary-side flow path 1 on the other side. In addition to receiving the secondary pressure and the secondary pressure of the secondary flow path, the pilot flow path is provided through the main valve, and the main valve is fixed to the pilot valve with a certain minute amount. A valve that controls the feed water flow rate by moving in the same direction following the movement of the pilot valve while maintaining a simple following gap.

  According to a third aspect of the present invention, in the first aspect, the water supply control valve switches the flow path from open to closed or vice versa, with the main valve being held at either the fully open position or the fully closed position. It is an on-off valve.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the seal portion of the differential pressure sensing portion of the constant differential pressure valve is a diaphragm film.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the back pressure chamber also serves as a storage chamber for the biasing member.

  As described above, the present invention receives the pressure of the back pressure chamber on one side, receives the primary side pressure of the primary flow path with respect to the main valve on the other side on the other side, and detects the primary side pressure and back pressure. A valve body having a differential pressure sensing portion that senses a differential pressure with respect to the pressure chamber pressure, and a biasing member that applies a biasing force to the valve body in the direction of the pressure of the back pressure chamber. By adding a constant differential pressure valve that makes the differential pressure between the back pressure chamber pressure and the primary side pressure constant by changing the throttle with respect to the flow path by the throttle part provided in the pilot water supply control valve, The pressure difference between the primary side flow path and the secondary side flow path of the main valve is kept constant.

  In the present invention, the pressure applied to the differential pressure sensing part of the constant differential pressure valve is the primary side pressure and the back pressure chamber pressure of the primary side flow path with respect to the main valve, and these pressures are under the main valve closed state. Therefore, a large force due to the differential pressure is not applied to the seal portion of the differential pressure sensing portion under the main valve closed state.

  As a result, it is possible to prevent the seal portion from leaking due to a large differential pressure applied to the seal portion of the differential pressure sensing portion under the main valve closed state, and the main valve is closed by the leak of the seal portion. Despite being in the valve state, it is possible to prevent the upstream water from leaking to the downstream side of the main valve.

  Accordingly, in order to reduce the sliding resistance during the operation of the differential pressure sensing part, even when the diaphragm film is used as the seal part of the differential pressure sensing part in the constant differential pressure valve (Claim 4), the diaphragm film is pressure resistant. For securing, it is not necessary to include a base fabric, and the cost required for the diaphragm membrane can be kept low.

  Moreover, even if a minute leak occurs in the seal part due to the differential pressure applied to the differential pressure sensing part under the main valve open state, the leak is a leak from the primary side flow path to the back pressure chamber. Yes, the flow of water from the primary side flow path to the back pressure chamber is originally generated through the introduction small hole, so that there is almost no adverse effect on the performance of the water supply control valve device due to the above leakage. .

  In the present invention, the pilot-type water supply control valve is configured such that the main valve receives the pressure of the back pressure chamber on one side and the primary side pressure and the secondary side channel on the other side on the opposite side. And a valve that controls the feed water flow rate by moving in the same direction following the movement of the pilot valve while maintaining a constant minute follow-up gap between the main valve and the pilot valve. (Claim 2).

  Alternatively, the water supply control valve can be an open / close valve that switches the flow path from open to closed or vice versa, with the main valve held in either the fully open position or the fully closed position. ).

  The fifth aspect of the present invention is such that the back pressure chamber also serves as a housing chamber for the urging member. According to the fifth aspect, the configuration of the valve device can be simplified.

It is the figure which showed the water supply control valve apparatus which is one Embodiment of this invention in the valve opening state. It is the figure which showed the water supply control valve apparatus of FIG. 1 in the valve closing state. It is the figure which showed the water supply control valve apparatus of other embodiment of this invention in the valve opening state. It is the figure which showed the water supply control valve apparatus of FIG. 3 in the valve closing state. It is the figure which showed the water supply control valve apparatus of other embodiment of this invention in the valve opening state. It is the figure which showed the water supply control valve apparatus of FIG. 5 in the valve closing state. It is a figure of the water supply control valve apparatus as a comparative example.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2, reference numeral 10 denotes a water supply control valve device according to the present embodiment, reference numeral 12 denotes a body thereof, and a flow path 14 is provided inside.
In this embodiment, the water supply control valve device 10 includes a pilot-type water supply control valve (hereinafter simply referred to as a water supply control valve) 16 and a constant differential pressure valve 18.

Reference numeral 20 denotes a main valve in the water supply control valve 16, which is a diaphragm valve, and includes a rubber diaphragm film 22 and a hard holding member 24 that holds the diaphragm film 22.
The diaphragm membrane 22 has an outer peripheral portion fixed to the body 12 over the entire circumference, and also has a function as a seal portion for sealing a space between a back pressure chamber 34 and a primary side flow passage 30 described later. Yes.

The main valve 20 is seated on the main valve seat 28 at the tip of the cylindrical portion 26 provided on the body 12 and is closed to shut off the primary flow path 30 and the secondary flow path 32 with respect to the main valve 20. .
Further, the valve is opened away from the main valve seat 28 in the upward direction in the figure, and the primary side flow path 30 and the secondary side flow path 32 are brought into communication with each other, and a flow of water passing through the main valve 20 is generated.
Further, by changing the opening degree, the flow rate of water flowing from the primary side flow path 30 to the secondary side flow path 32, that is, the flow rate of water supply is changed according to the opening degree.

A back pressure chamber 34 is provided behind the upper side of the main valve 20 in the figure.
The back pressure chamber 34 causes the internal pressure to act on the main valve 20 as a pressing force in the downward valve closing direction in the figure.
The main valve 20 is provided with a small introduction hole 36 penetrating therethrough at a position eccentric from the center thereof.
The introduction small hole 36 introduces the water in the primary channel 30 into the back pressure chamber 34 and increases the pressure in the back pressure chamber 34.
The main valve 20 is also provided with a pilot flow path 38 as a water drainage passage penetrating the main valve 20.
The pilot flow path 38 reduces the pressure in the back pressure chamber 34 by drawing water from the back pressure chamber 34 into the secondary flow path 32.

Reference numeral 40 denotes an operating shaft that protrudes to the outside of the body 12, and a pilot valve 42 is integrally formed at the tip (lower end in the figure).
The pilot valve 42 is closed by seating a seal portion 44 on a pilot valve seat 46 provided in the main valve 20, and water reaching the secondary side flow path 32 from the back pressure chamber 34 through the pilot flow path 38. Cut off the flow.
Further, by opening the valve valve 46 away from the pilot valve seat 46 in the upward direction in the figure, a flow of water from the back pressure chamber 34 to the secondary flow path 32 through the pilot flow path 38 is generated.

A male screw portion 48 is provided on the outer peripheral surface of the operation shaft 40, and the male screw portion 48 is screwed into a female screw portion 50 of a female screw hole provided in the body 12.
Therefore, when the operating shaft 40 is rotated, the pilot valve 42 is moved back and forth in the vertical direction in the drawing by the screw mechanism 52 including the male screw portion 48 and the female screw portion 50.

In this example, the water supply control valve 16 is a valve capable of continuously adjusting the flow rate of the water supply, and the flow rate is adjusted by rotating the operation shaft 40.
FIG. 2 shows a state in which the operating shaft 40 is rotated in one direction so that the pilot valve 42 protrudes downward to the full stroke and is closed.
At this time, the main valve 20 is also seated on the main valve seat 28 and closed, and no water flows from the primary side flow path 30 to the secondary side flow path 32.

In this state, when the operating shaft 40 is rotated in the opposite direction to move the pilot valve 42 upward in the figure, a gap is created between the pilot valve 42 and the pilot valve seat 46, that is, the main valve 20, and the back. The water in the pressure chamber 34 flows out from the gap through the pilot channel 38 to the secondary channel 32, and the pressure in the back pressure chamber 34 decreases.
Thus, the main valve 20 is pushed up upward in the drawing to open the primary pressure P ₂ of the primary flow path 30.

Then, the force by the back pressure chamber pressure P ₄ applied downward to the main valve 20, the primary pressure P _{2 of the} primary flow path 30 applied upward, and the secondary pressure P _{3 of the} secondary flow path 32. The main valve 20 stops moving at a position where the force generated by the balance is balanced.

When the pilot valve 42 is further moved backward in the figure from this state, the gap between the pilot valve 42 and the main valve 20 is increased again, and the back pressure chamber pressure P ₄ temporarily decreases again to temporarily reduce the main pressure. The valve 20 moves upward in the figure.

Then a downward force due to the back pressure chamber pressure P _4, and in the drawing upward force by the primary side pressure P ₂ and the secondary side pressure P ₃ is stopped there again at a position balanced.
Then, the opening degree of the main valve 20 is increased by the upward movement of the main valve 20 in the figure, and the water flowing from the primary side flow path 30 to the secondary side flow path 32 as the opening degree of the main valve 20 increases. The flow rate of the gas increases and changes.

The main valve 20 moves in the same direction, that is, upward in the figure as the pilot valve 42 further moves upward in the figure, further increasing the valve opening and further increasing the flow rate of water flowing through the flow path.
However, as an actual movement, the pilot valve 42 is maintained while maintaining a constant minute follow-up gap d (this gap is a minute gap of about 0.03 mm) between the main valve 20 and the pilot valve 42, more specifically, the seal portion 44. Following the backward movement of the valve 42, the valve 42 moves in the same direction, and the opening degree of the flow path 14 is changed.

Similarly, when the pilot valve 42 moves forward in the figure downward, the main valve 20 follows the movement of the pilot valve 42 while keeping a certain minute gap d between the main valve 20 and the pilot valve 42 downward in the figure. And the flow rate of water flowing through the flow path 14 is continuously decreased.
Then, the pilot valve 42 moves forward downward in the drawing until the stroke is full, and the pilot valve 42 is in a closed state, so that the main valve 20 is also seated on the main valve seat 28 and is in a closed state. Stop the flow of water.

The constant differential pressure valve 18, by the pressure difference between the back pressure chamber pressure P ₄ and 1 of primary channel primary pressure P ₂ in the back pressure chamber 34 constant, the primary side pressure P ₂ and 2 in a valve having a function of a differential pressure between the secondary pressure P ₃ of the following side flow path 32 at a constant, reference numeral 54 is a valve body which forms the principal.
The valve body 54 includes a differential pressure sensing portion 56 that senses a differential pressure between the back pressure chamber pressure P ₄ and the primary pressure P _2, and a flow path from the inlet flow path 58 to the primary flow path 30. It has a diaphragm and a diaphragm section 60 that changes the diaphragm, and these are connected by a shaft section 62.

The differential pressure sensing part 56 is of a diaphragm type and has a rubber diaphragm film 64 and a hard holding part 66 for holding the diaphragm film 64.
The outer peripheral portion of the diaphragm membrane 64 is fixed to the body 12 in a watertight manner, and the diaphragm membrane 64 also has a function as a seal portion for sealing between the back pressure chamber 34 and the primary flow path 30 in a watertight manner. Yes.
Here the differential pressure sensing portion 56, an upward one surface subjected to downward back pressure chamber pressure P ₄ in (in the figure the upper surface), also of the opposite other surface of the primary-side pressure P ₂ in (in the drawing the underside) the receiving, senses the differential pressure thereof back pressure chamber pressure P ₄ and the primary-side pressure P _2.

On the other hand, the throttle part 60 is slidably fitted in a fitting hole 72 formed in the body 12.
The throttle portion 60 is provided with a communication hole 74 communicating with the space on the bottom side of the fitting hole 72.
The outer peripheral surface of the throttle portion 60 and the inner peripheral surface of the fitting hole 72 are sealed in a watertight manner by an O-ring.

Constant differential pressure valve 18, in addition to the valve body 54, and a coil spring (biasing member) 68 which exerts its biasing force in the direction of action of the back pressure chamber pressure P ₄ with respect to the differential pressure sensing portion 56.
Here, the coil spring 68 is housed in a housing chamber 70 that forms a part of the back pressure chamber 34, one end (upper end in the figure) is brought into contact with the body 12, and the other end is placed on the differential pressure sensing part. 56, and the biasing force is applied downward.

The constant differential pressure valve 18 maintains a pressure difference between the back pressure chamber pressure P ₄ operates as follows: the primary side pressure P ₂ constant.
That is, when the back pressure chamber pressure P ₄ increases under the valve open state of the main valve 20, the valve body 54 is pushed downward by the increased back pressure chamber pressure P ₄ .
Then stop the flow channel by the throttle portion 60 becomes small, the primary side pressure P ₂ increases. The valve body 54 is moved stops at that elevated by moving the primary side pressure P ₂ and the back pressure chamber pressure P ₄ are balanced position.
Further, when the back pressure chamber pressure P ₄ is lowered conversely, relatively increased the inlet pressure P ₂ in the valve body 54 is large cities the aperture by diaphragm portion 60 is pushed up upward in the figure, the primary side pressure lowering the P _2.
The back pressure chamber pressure P ₄ and the primary-side pressure P ₂ and the valve body 54 are balanced position to stop moving.
In this way, the valve body 54 operates so as to always keep the differential pressure ΔP between the back pressure chamber pressure P ₄ and the primary pressure P ₂ constant.

In this example, the pressure receiving area of the main valve 20 that receives the back pressure chamber pressure P ₄ under the open state of the main valve 20 (that is, under the water supply state) is S ₁ , and the main valve 20 that receives the secondary pressure P _3. Where S _{2 is} the pressure receiving area and (S ₁ -S ₂ ) is the pressure receiving area of the main valve 20 that receives the primary pressure P ₂ , the following equation (2) holds.
Equation _{(2) ··· P 4 S 1} = P 2 (S 1 -S 2) + P 3 S 2
When this equation (2) is converted, the following equation (3) is obtained.
Equation _{(3) ··· (P 2 -P} 3) S 2 = (P 2 -P 4) S 1

In Formula (3), since the differential pressure between the primary pressure P ₂ and the back pressure chamber pressure P ₄ is held constant by the constant differential pressure valve 18, the primary pressure P ₂ , the secondary pressure P ₃ , The differential pressure is also kept constant.
That the constant differential pressure valve 18, the differential pressure between the primary side pressure P ₂ and the secondary side pressure P ₃ is kept constant.
Therefore, the flow rate of the water flowing through the flow path 14, that is, the flow rate of the feed water is a constant flow rate according to the opening of the main valve 20.

On the other hand, under the water stoppage state, that is, under the valve closing state of the main valve 20 shown in FIG. 2, no flow of water occurs in the flow path 14, so the back pressure chamber pressure P ₄ = secondary side pressure P ₂ = inlet side the entrance side pressure P ₁ of the flow channel.
That is, under the water stop condition, the force due to the differential pressure does not act on the diaphragm film 64 in the differential pressure sensing portion 56 of the constant differential pressure valve 18, and therefore the diaphragm film 64 functioning as a seal portion leaks due to the force due to the differential pressure. Does not occur.

Even if leakage occurs, it does not cause leakage of water to the secondary flow path 32 under the closed state of the main valve 20.
Diaphragm membrane of the differential pressure sensing portion 56 64 is because not received secondary pressure P ₃ of the secondary-side flow path 32 directly. That is, the flow path in contact with the diaphragm film 64 and the secondary flow path 32 are blocked by the main valve 20.

On the other hand, when the main valve 20 is open, that is, under a water supply state, a differential pressure between the back pressure chamber pressure P ₄ and the primary pressure P ₂ acts on the diaphragm membrane 64 of the differential pressure sensing portion 56.
Provided that the pressure difference is not a differential pressure larger the differential pressure between the primary side in FIG. 7 the pressure P _{2 =} P ₁ and the secondary side pressure P _2, hardly occurs that such diaphragm membrane 64 to generate a leakage Even if leakage occurs in this state, the water in the primary flow path 30 only flows into the back pressure chamber 34 from the location of the diaphragm membrane 64 where the leakage occurred, and the primary side flow The inflow of water from the passage 30 to the back pressure chamber 34 is originally generated through the introduction small hole 36.
Accordingly, the minute leakage hardly affects the performance of the water supply control valve device 10.

  In the present embodiment, in order to reduce the sliding resistance during operation of the differential pressure sensing part 56, even if the diaphragm film 64 is used as the seal part, the diaphragm film 64 is included in the base cloth for ensuring the pressure resistance. The cost required for the diaphragm film 64 can be kept low.

3 and 4 show another embodiment of the present invention.
This embodiment is an example in the case where the water supply control valve 16 is an on-off valve. Here, the plunger-type pilot valve 76 is driven by an electromagnetic coil 78 that generates an electromagnetic force by energization.
In the water supply control valve device 10 of this example, the pilot valve 76 is held at either the forward end, that is, the fully closed position, or the backward end, that is, the fully opened position.

Specifically, when the electromagnetic coil 78 is energized, the electromagnetic coil 78 pulls up the pilot valve 76 upward in the drawing by electromagnetic force to the full stroke and holds it in the fully open position.
When the valve is closed, as shown in FIG. 4, the coil spring 80 projects the pilot valve 76 downward in the drawing to the full stroke and holds it in the closed position.
Accordingly, the main valve 20 is held in a fully open position in which the main valve 20 is retracted upward in the drawing to the full stroke and in a fully closed position in which the main valve 20 is moved downward in the drawing to the full stroke.

Thus, when the pilot valve 76 and the main valve 20 move in the backward direction to the full stroke and reach the fully open position, as shown in FIG. 3, the pilot valve 76, more specifically, the seal portion 44 and the main valve 20 A sufficiently large gap S is generated between them.
Therefore, under the open state of the pilot valve 76 and main valve 20, the secondary pressure P ₃ of the back pressure chamber pressure P ₄ secondary flow path substantially equal to the pressure _(P 4 ₌ P ₃₎ (The pilot channel 38 is sufficiently expanded with respect to the introduction small hole 36).

On the other hand, since the differential pressure (P ₂ −P ₄ ) between the primary pressure P ₂ and the back pressure chamber pressure P ₄ is held constant by the constant differential pressure valve 18, the primary pressure P ₂ and the secondary pressure P The differential pressure from ₃ is also kept constant.
On the other hand, when the water is stopped, that is, when the main valve 20 is closed, no flow of water occurs in the flow path 14, so the back pressure chamber pressure P ₄ = primary side pressure P ₂ = inlet side pressure P _1. It becomes.
In the embodiment of FIGS. 3 and 4, the other configurations are basically the same as those of the above embodiment.
This embodiment also has the same effect as the above embodiment.

5 and 6 show still another embodiment of the present invention.
Also in this example, the water supply control valve 16 is an on-off valve and the main valve 20 is a piston valve, and the main valve 20 slides up and down in the drawing along the inner surface of the cylinder chamber 84. ing.
An O-ring is held on the outer peripheral surface of the main valve 20 composed of a piston valve, and the space between the main valve 20 and the inner surface of the cylinder chamber 84 is sealed in a watertight manner by the O-ring.

In this example, an introduction small hole 36 for communicating the primary side flow path 30 and the back pressure chamber 34 is provided through the body 12, and the pilot flow path 38 does not penetrate the main valve 20. It is provided through the body 12.
A pilot valve 86 is disposed on the pilot flow path 38, and the pilot valve 86 is seated on or separated from the pilot valve seat 88.

The pilot valve 86 is configured at the tip of the operation shaft 40, and the operation shaft 42 is provided with a male screw portion 48, and this male screw portion 48 is screwed into the female screw portion 50 of the female screw hole of the body 12. The male screw portion 48 and the female screw portion 50 constitute a screw mechanism 52.
A rotation operation unit 90 is provided at the end of the operation shaft 40 exposed to the outside from the body 12.

In the present embodiment, the differential pressure sensing portion 56 in the constant differential pressure valve 18 is configured by a piston portion 92 and an O-ring 94 as a seal portion, and the differential pressure sensing portion 56 extends along the inner surface of the cylinder chamber 96. In the figure, it can slide up and down.
Other configurations are the same as those of the embodiment shown in FIGS.

In this example, when the pilot valve 40 is closed as shown in FIG. 6, the main valve 20 is held in the closed position, and as shown in FIG. 5, the pilot valve 40 is largely retracted to the right in the drawing to open the valve. As a result, the main valve 20 is held in the fully open position.
The flow path is switched from closed to open and vice versa by the movement of the main valve 20 between the fully closed position and the fully open position.

In FIG. 5 in which the main valve 20 is in the fully open position, the secondary side flow path 32 is in communication with the back pressure chamber 34 via the pilot flow path 38, and the pilot valve 40 is in a largely open state. Since a large gap S is generated between the pilot valve 86 and the pilot valve seat 88, the back pressure chamber pressure P ₄ = the secondary pressure P ₃ .

Further, since the differential pressure (P ₂ -P ₄ ) between the secondary pressure P ₂ and the back pressure chamber pressure P ₄ is held constant by the constant differential pressure valve 18, the primary pressure P ₂ and the secondary pressure the differential pressure between the pressure _{P 3 (P} 2 -P ₃₎ is also held at a constant differential pressure.
Therefore, also in this example, the flow rate of water flowing through the main valve 20 is a constant flow rate.

The main valve 20 including the piston valve in this example is opened from the closed state shown in FIG. 6 by the momentum of water flow from the primary side flow path 30 to the secondary side flow path 32.
On the other hand, when the pilot valve 86 is closed, the main valve 20 is closed by the increased back pressure chamber pressure P ₄ , and under the state where the main valve 20 is closed, the back pressure chamber pressure P ₄ is the primary side. The pressure P ₂ = the pressure equal to the entry side pressure P ₁ .

  Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be configured in various forms without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Water supply control valve apparatus 14 Flow path 16 Pilot type water supply control valve 18 Constant pressure valve 20 Main valve 30 Primary side flow path 32 Secondary side flow path 34 Back pressure chamber 36 Introduction small hole 38 Pilot flow paths 42, 76, 86 Pilot valve 54 Valve body 56 Differential pressure sensing part 60 Throttle part 64 Diaphragm film 68 Coil spring 70 Storage chamber

Claims (5)

(A) (a) a main valve provided in the flow path, (b) a back pressure chamber in which the internal pressure acts on the main valve as a pressing force in the valve closing direction, and (c) one for the main valve. An introduction small hole that introduces water in the secondary flow path into the back pressure chamber to increase the pressure in the back pressure chamber; and (d) drains the water in the back pressure chamber into the secondary flow path to the main valve. A pilot flow path that reduces the pressure in the back pressure chamber; and (e) a pilot valve that controls the operation of the main valve by controlling the flow of water flowing out of the back pressure chamber through the pilot flow path; To the pilot-type water supply control valve equipped with
(B) (f) The pressure of the back pressure chamber is received on one surface, the primary pressure of the primary flow path is received on the other surface on the opposite side, the primary pressure and the back pressure chamber pressure. And (g) a biasing member that applies a biasing force to the valve body in the direction of the pressure of the back pressure chamber. A constant differential pressure valve that makes the differential pressure between the back pressure chamber pressure and the primary side pressure constant by changing the throttle with respect to the flow path by the throttle part provided in the valve body under the open state of the main valve The water supply control valve device is characterized in that the differential pressure between the primary side flow path and the secondary side flow path is kept constant by adding. 2. The water supply control valve according to claim 1, wherein the main valve receives the pressure of the back pressure chamber on one side, and the primary side pressure and the secondary side of the primary channel on the other side on the opposite side. Receiving the secondary side pressure of the side channel,
The pilot flow path is provided through the main valve;
The main valve is a valve that controls the feed water flow rate by moving in the same direction following the movement of the pilot valve while maintaining a constant minute follow-up gap with the pilot valve. Control valve device.   2. The on-off valve according to claim 1, wherein the water supply control valve is an on-off valve that switches the flow path from open to closed or vice versa, with the main valve being held in either a fully open position or a fully closed position. A water supply control valve device.   4. The water supply control valve device according to claim 1, wherein a seal portion of the differential pressure sensing portion of the constant differential pressure valve is a diaphragm membrane.   5. The water supply control valve device according to claim 1, wherein the back pressure chamber also serves as a storage chamber for the biasing member.

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