JPH06242837A - Pressure reducing valve - Google Patents

Abstract

PURPOSE:To perform the switching of preset pressure to low pressure setting and high pressure setting automatically and in a moment by moving the fulcrum side of a reducing spring in the direction of spring pressure of the spring, with a pressure reception driving member. CONSTITUTION:A diaphragm 3 interlocking with the valve 20 of a pressure reducing valve mechanism 2 is pressed on the pressure sensitive room 14 side of secondary pressure. The fulcrum side of the reducing spring (a) on which the secondary pressure that becomes a preset pressure is set, is moved in the direction of spring pressure of the reducing spring (a) by a pressure reception driving member D driven by a hydraulic force introduced from the primary side (w). In such a way, the switching of the preset pressure of the reducing valve to the high pressure setting and the low pressure setting can be performed. Thereby, the switching of preset pressure in two steps of high/low from high to low and low to high can be performed automatically and in a moment. Also, when hot water of a high pressure is taken out as keeping pressure in a can safely by switching supply water pressure to high/low, the switching of high/low can be performed by one reducing valve, which attains cost reduction. Furthermore. it is possible to omit a low pressure/high pressure relief valve when this valve is used as a pressure reducing relief valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly increases the water supply pressure to a water heater when the hot water tap is opened and hot water is used, and when the hot water tap is closed to stop using hot water. The invention relates to a pressure reducing valve developed for use in a hot water supply device that allows the user to take out high-pressure hot water that is convenient to use while keeping the pressure inside the can of the water heater safe.

More specifically, as described above, the water supply pressure to the water heater is switched between two stages, high and low, depending on whether hot water is used or hot water is stopped. The present invention relates to an improvement of a pressure reducing valve in which a set pressure is switched between high and low stages so that the hot water supply apparatus can be adapted for use.

[0003]

2. Description of the Related Art A conventional pressure reducing valve is a pressure reducing relief valve having a relief valve incorporated therein. As shown in FIG. 1, an inlet pipe 10 connected to a primary side and an outlet connected to a secondary side are provided on an outer surface of a peripheral wall. In the valve box 1 provided with the pipe 11, a partition wall 12 for blocking the primary side w and the secondary side y in the valve box 1 is provided, and a tubular portion whose axial direction is a vertical direction is provided in the partition wall 12. 13 is provided so that the communication port provided on the cylindrical wall thereof communicates with the primary side w and the open port on the lower end side communicates with the secondary side, and below the open port at the lower end of the tubular portion 13, The valve body 20 of the pressure reducing valve is arranged so as to face the valve seat 21 provided at the opening so as to move back and forth.

Then, the valve shaft 22 integrally connected to the valve body 20 is thrust into the cylindrical portion 13 to form the valve shaft 2
A balance valve 23 that fits and slides on the wall surface of the tubular portion 13 in a watertight manner is provided on the upper end side of 2, and the upper end side of the balance valve 23 is opened from the opening on the upper end side of the tubular portion 13. It is made to project into the pressure sensing chamber 14 formed on the upper surface side of the valve box 1 and which senses the secondary pressure, and the projecting end portion is attached to the diaphragm 3 provided on the upper surface side of the pressure sensing chamber 14 and the diaphragm thereof. 3, a pressure reducing spring a which is connected to move integrally with the diaphragm 3 and is stretched between the diaphragm 3 and a spring case 15 mounted on the upper surface side thereof.
Thus, the spring pressure of the pressure-reducing spring a is adjusted to a desired value by pushing down the pressure-reducing chamber 14 and supporting the upper end side of the pressure-reducing spring a with the adjusting screw b screwed into the spring case 15. In this way, the pressure reducing valve A is configured.

When the pressure reducing valve A has a form in which the relief valve mechanism 4 is incorporated, a relief valve valve body 40 is provided on the upper end side of the balance valve 23 as shown in FIG. The diaphragm 3 is provided with a relief port 41, and an annular valve seat 42 for the relief valve facing the valve body 40 is provided on the lower surface side of the rim of the diaphragm 41, and the above-mentioned valve shaft is provided. By incorporating the spring 5 that pushes it up at the lower end side of 22, the valve body 40 for the relief valve is pushed up by this spring 5, and in the normal state, the state of being joined to the valve seat 42 is maintained, In the state where the valve body 20 for the pressure reducing valve collides with the valve seat 21 for the pressure reducing valve due to the increase in the pressure on the secondary side y and the movement upward is blocked, the pressure sensitive chamber When a larger pressure is applied to 14 and the diaphragm 3 rises, this valve seat 42 is released. From the valve body 40 of the use are to cooperative to continue to open the spill port 41 away upwards.

[0006]

Since the pressure reducing valve has the above-mentioned structure, when setting the set pressure thereof, the pressure reducing spring a is assembled and pressure is applied from the primary side to set the secondary pressure. It is performed by rotating the adjusting screw b while measuring.

Therefore, the set pressure can be changed by rotating the adjusting screw b. However, in the case of automatically making variable, the only means is to rotate the adjusting screw b by a motor. Moreover, since the spring pressure of the pressure-reducing spring a is changed by the axial movement accompanying the rotation of the adjusting screw b, the change is slow. Therefore, even if the pressure reducing valve of the related art is automatically variable in set pressure, it cannot be used in the hot water supply device described above so as to switch the water supply pressure to the water heater to high or low. There's a problem.

[0008]

[Purpose] The present invention has been made to solve this problem occurring in a conventional pressure reducing valve.
An object of the present invention is to provide a new means for adapting to the above-described hot water supply device by configuring a pressure reducing valve so that the operation of switching from high to low and from low to high can be performed automatically and instantaneously. And

[0009]

As a means for achieving the above object, the present invention provides a fulcrum side of a pressure reducing spring which acts on a diaphragm connected to a valve body of a pressure reducing valve mechanism to set a set pressure. By a pressure receiving drive member provided so as to be driven by water pressure on the primary side, to bring about a pressure reducing valve in which the set pressure is switched between high pressure setting and low pressure setting by moving in the spring pressure direction of the pressure reducing spring. It is a thing.

[0010]

Embodiments Next, embodiments will be described in detail with reference to the drawings. The same reference numerals are used for the constituent elements having the same effect as those of the conventional means.

FIG. 2 is a vertical sectional front view of a pressure reducing valve A according to the present invention. In FIG. 2, 1 is a valve box and 10 is its valve box 1.
An inlet pipe provided on one side of the peripheral wall, 11 an outlet pipe provided on the other side of the peripheral wall, and 12 provided in the valve box 1 so as to separate the primary side w and the secondary side y in the valve box 1. A partition wall, 13 is a cylindrical portion provided inside the valve box 1 by communicating a communication port provided on the cylindrical wall with the primary side w, and 14 is an upper surface side of the valve box 1 above the partition wall 12 and the cylindrical portion 13. The pressure-sensitive chamber 20 for secondary pressure formed at 20 is arranged below the opening at the lower end of the tubular portion 13 and moves forward and backward from below with respect to the valve seat 21 formed at the edge of the opening at the lower end. A valve body 22 freely opposed to each other, 22 is a valve shaft whose lower end side is integrally connected to the valve body 20, and 23 is integrally formed on the upper end side of the valve shaft 22 so as to be integrally formed. A balance valve fitted in a lumen so as to be watertight and freely slidable, 3 is a diaphragm for separating the upper surface side of the pressure-sensitive chamber 14 from the outside, and 30 is this die. Fram 3 the upper side and the interlocking screw which interlocking of the balance valve 23, a pressure reducing spring biases push down toward the diaphragm 3 in the pressure sensitive chamber 14, 15
Is a spring case which is arranged on the upper surface side of the diaphragm 3 so as to store the pressure reducing spring a and is attached to the upper surface side of the valve box 1, b
Is an adjusting screw screwed into the spring case 15 so as to change and adjust the set pressure by changing the spring pressure of the pressure reducing spring a, and these are the same as those of the conventional pressure reducing valve.

However, the pressure reducing spring a for pushing down the diaphragm 3 toward the pressure sensing chamber 14 has the adjusting screw b at the upper end thereof.
It is formed separately and is supported by a spring support seat 60 provided on the lower surface side of the adjusting screw b so as to be vertically movable.

The spring support seat 60 is movably connected to the operating member 6 housed in the spring case 15 so that the spring pressure of the pressure reducing spring a is changed by the upward and downward movement of the operating member 6. It is done.

Further, above the operating member 6,
A pressurizing chamber K is formed by a block 70 assembled on the upper surface side of the spring case 15, and inside the pressurizing chamber K is formed.
A pressure receiving drive member D that moves downward due to an increase in internal pressure and pushes the operating member 6 downward and is increased by a restoring spring 71 due to a decrease in pressure inside the pressurizing chamber K is stored.

A pressure receiving drive member D for driving the operating member 6.
In this embodiment, the piston is formed in the pressurizing chamber K so as to be watertight and fitted vertically slidably. However, as in the embodiment of FIG. 5 described later, the piston is formed in the diaphragm. There is a case.

The pressurizing chamber K communicates with a conduit P1 communicating with the atmosphere and a conduit P2 communicating with the primary side w in the valve box 1 through a communicating passage 72, and the communicating passage 72 thereof. And pipeline P1
The communication with the pipe line P2 is performed by the valve V operated by the electromagnet S mounted on the outer surface side of the valve casing 1 and the pipe line P2 connected to the primary side w in the valve casing 1 and the atmosphere. It is arranged to switch to a state in which it communicates with the open pipeline P1.

Then, when the valve V is moved to the position shown in FIG. 3 by the excitation of the electromagnet S, and the pipe P1 is opened and the pipe P2 is blocked with respect to the communication passage 72, pressurization is performed. Since the chamber K communicates with the atmosphere, the pressure receiving drive member D
Moves upward due to the spring pressure of the restoring spring 71, and with this,
The spring support seat 60 with which the operating member 6 is integrally connected
Rises until the upper surface of the pressure reducing valve mechanism 2 and the lower surface of the adjusting screw b are joined, and the set pressure of the pressure reducing valve mechanism 2 is set to the pressure set by the adjusting screw b.

When the excitation of the electromagnet S is released, the valve V
Moves to the position shown in FIG.
Is cut off and the pipeline P2 is in a state of communication,
The water pressure on the primary side w flows into the pressurizing chamber K, whereby
The pressure receiving drive member D moves downward and pushes down the operating member 6 located below it until the collar portion 6a formed on the upper edge of the operating member 6 abuts the upper surface of the adjusting screw b. The pressure reducing spring a is pressed and contracted to increase the spring pressure. Therefore, the set pressure of the pressure reducing valve mechanism 2 to be set by the force of the pressure reducing spring a is switched to the high pressure setting. Then, the set pressure at this time is set at the position of the upper surface of the adjusting screw b that restricts the downward movement of the operating member 6 and the position of the lower surface of the collar portion 6a of the operating member 6 that abuts the upper surface of the adjusting screw b. It will be set according to the thickness of the collar portion 6a to be determined.

Therefore, in the pressure reducing valve A of this embodiment, when the excitation of the electromagnet S is turned on, the pressurizing chamber K communicates with the atmosphere and the pressure receiving drive member D moves downward only by its own weight. The force to push down the operating member 6 is lost, and the decompression spring a
Remains set by the adjusting screw b, and the set pressure is set to low pressure. When the excitation of the electromagnet S is off, the water pressure on the primary side w is applied to the pressurizing chamber K, and the product of the water pressure and the pressure receiving area of the pressure receiving driving member D pushes down the pressure receiving driving member D. .

The spring force of the decompression spring a depends on the pressure receiving area of the diaphragm 3, but is usually about 26 kgf, so the force for pushing down the pressure receiving drive member D may be about 30 kgf, and the water pressure is 2 kgf. If it does, it will become 15 cm < ² >, and if the pressure receiving drive member D with a diameter of 4.4 cm is sufficient.

The valve V operated by the electromagnet S includes a conduit P2 for guiding the pressure on the primary side w to the pressurizing chamber K and a conduit P1 for excluding the pressure from the pressurizing chamber K. Since it is simply switched so as to communicate with each other, an extremely small size will suffice.

Further, in this embodiment, by energizing the electromagnet S, the pressurizing chamber K communicates with the atmosphere through the pipe line P1 to set a low pressure. High pressure is set by communicating with the primary side w via the path P2, but when the energization of the electromagnet S is turned off, the pressurizing chamber K communicates with the atmosphere and becomes low pressure setting, and when the energization is turned on. There is a case where the pressurizing chamber K communicates with the primary side w and is switched so as to switch to the high pressure setting. Considering the case where the energization to the electromagnet S is cut off due to a power failure or the like, it is preferable that the pressurizing chamber K communicates with the atmosphere and has a low pressure when the energization is turned off.

In the illustrated embodiment, 16 is a check valve incorporated in the primary side w of the valve box 1, and 17 is a vacuum breaking valve.

Next, FIG. 4 shows another embodiment. This embodiment is an example in which the decompression spring a is divided into two, a low pressure setting spring a-1 and a high pressure setting spring a-2. Further, this embodiment is an example in which the pressure reducing valve mechanism 2 is applied to the pressure reducing valve A in which the relief valve mechanism 4 is incorporated as in the conventional example of FIG. That is, in this embodiment, the valve shaft 2 of the pressure reducing valve mechanism 2 is
A valve body 40 for a cylindrical valve type relief valve is provided on the upper surface side of the balance valve 23 integrally formed on the upper end side of 2, and a relief port 41 is opened in the diaphragm 3 and the relief port 41 is formed. An annular valve seat 42 for a relief valve that faces the valve body 40 is provided on the lower surface side of the rim of the valve body, and a spring 5 that pushes up the valve shaft 22 is installed on the lower end side of the valve shaft 22 to reduce the pressure. During the depressurization operation of the mechanism 2, the relief valve valve body 40 is moved to the relief valve valve seat 42.
It is connected to the diaphragm 3 so as to move integrally with the diaphragm 3 while keeping the escape port 41 closed by colliding with the
When the pressure of the pressure reducing valve mechanism 2 causes the valve body 20 of the pressure reducing valve mechanism 2 to collide with the valve seat 22 and the upward movement is blocked, when the pressure on the secondary side y further increases, the relief valve is released. The valve seat 42 for the valve is separated upward from the valve body 40 for the relief valve, and the relief port 4
1 is opened to release the pressure to the outside, which is no different from the conventional pressure reducing relief valve. Since this point is not related to the means of the present invention for switching the set pressure of the pressure reducing valve to two stages of high and low, detailed description thereof will be omitted below.

Further, in this embodiment, the remaining structure except that the above-mentioned pressure reducing spring a is two and the above-mentioned relief valve mechanism 4 is incorporated is shown in FIG. The components are the same as in the embodiment, and the components having the same effect are denoted by the same reference numerals.

However, as described above, the pressure reducing spring a, which is divided into two springs, the low pressure setting spring a-1 and the high pressure setting spring a-2, is one of the low pressure setting spring a-.
1, in the same manner as the pressure-reducing spring a in the conventional pressure-reducing valve A shown in FIG. 1, it is directly stretched between the adjusting screw b screwed into the spring case 15 and the diaphragm 3 to adjust the adjusting screw. It is configured as a decompression spring with a fixed spring pressure in which the set pressure is set by the adjustment position by the rotation of b.

The other high pressure setting spring a-2 is arranged so as to form a double spiral in the inner cavity of the low pressure setting spring a-1, and the upper surface of the diaphragm 3 is arranged. And a lower surface of the operating member 6 are stretched.

The actuating member 6 for supporting the upper end side of the high pressure setting spring a-2 is a pressure receiving drive member D provided in the pressurizing chamber K arranged on the upper surface side of the spring case 15 by an electromagnet S. The fact that the diaphragm 3 is moved up and down with respect to the diaphragm 3 by the operation of raising and lowering due to the pressure change in the pressurizing chamber K by the operation of the controlled valve V is the same as that of the embodiment shown in FIG. However, the adjustment screw b can be freely moved up and down.

Also, the high pressure setting spring a-2
Means that when the pressure receiving drive member D is raised by the restoring spring 71 due to the pressurization chamber K communicating with the atmosphere via the conduit P1, the actuating member 6 in the free state is pushed up, and the spring is pushed. It is set so that the pressure is zero and free.

Thus, in this embodiment, when the pressurizing chamber K is communicated with the atmosphere as shown in FIG. 4 by controlling the electromagnet S, only the spring pressure of the low pressure setting spring a-1 acts on the diaphragm 3. Then the low pressure is set and the pressurizing chamber K is shown in FIG.
When the pressure receiving drive member D is pushed down by water pressure by communicating with the primary side w as shown in FIG. -1 and high pressure setting spring a-2
Both of them act, and the set pressure increases by the added spring pressure of the high-pressure setting spring a-2, and the state is switched to the high-pressure setting state. Also in this embodiment, the relationship between the switching of the conduits P1 and P2 and the ON / OFF of the electromagnet S can be freely set as in the above-described embodiments.

Further, in this embodiment, the relief port 41 of the relief valve mechanism 4 is opened at the axial center portion of the diaphragm 3 and the inner cavity of the spring case 15 is used as a passage for releasing pressure. Pipe line P for connecting the pressurizing chamber K to the atmosphere
1 uses the discharge pipe 43 for discharging the pressure of the relief valve mechanism 4 provided in the spring case 15 to release the water to be opened to the inner cavity of the spring case 15 from the pressurizing chamber K. To lead to.

In this embodiment, since the low pressure setting spring a-1 does not have to be moved when switching between the high pressure setting and the low pressure setting, the low pressure setting is stable at the pressure set by the adjusting screw b. Becomes Further, since only the high pressure setting spring a-2 added to the spring pressure of the low pressure setting spring a-1 needs to be moved by the pressure receiving drive member D, the driving force of the pressure receiving drive member D may be small. Then, it becomes possible to miniaturize.

Next, FIG. 6 shows another embodiment. In this embodiment, the pressure reducing valve A is used to adjust the set pressure when the low pressure is set by rotating the adjusting screw b.
This is an example in which this can be done while it cannot be done after assembling. This embodiment is a modification of the embodiment shown in FIG. 2 described above, and the basic configuration is the same as that of the embodiment shown in FIG.

That is, the operating member 6 is integrally connected to the spring support seat 60 that supports the upper end side of the pressure reducing spring a, and the operating member 6 is mounted on the upper surface side of the spring case 15. The pressure receiving drive member D that can be stored in K is guided to the inside of the pressurizing chamber K through the conduit P2 and the water pressure on the primary side w, and the water pressure is discharged to the outside via the conduit P1, so that The operation of moving up and down to switch between the high pressure setting and the low pressure setting is the same as the embodiment of FIG.

However, the spring support seat 60 that supports the upper end of the pressure-reducing spring a is located at a position where the end of the ascending operation is restricted.
There is no adjusting screw b, and a stopper ST fixed inside the valve box 1 is arranged at this position. This stopper ST
The upper surface side thereof abuts the lower surface of the collar portion 6a of the actuating member 6 which is lowered by the pressure receiving drive member D, and also serves as a stopper which regulates the end of the descent operation of the pressure receiving drive member D and the operating member 6. It has become a thing.

The adjusting screw b is screwed on the ceiling wall of the pressurizing chamber K so that the lower end thereof projects into the pressurizing chamber K, and the lower end of the adjusting screw b drives the pressure receiving drive in the pressurizing chamber K. The upper surface of the member D abuts against the upper limit of the ascending operation of the pressure receiving drive member D, and the upper limit of the operating member 6 that follows the pressure receiving drive member D and ascends.

Therefore, in this embodiment, as shown in FIG. 7, the pressure receiving drive member D is lowered by the water pressure on the primary side w by the opening of the conduit P2 by the control of the electromagnet S and is pushed down by it. When the collar portion 6a of the above abuts against the upper surface of the stopper ST and the state held at that position becomes a high pressure setting, and the pressure of the pressurizing chamber K is released as shown in FIG. 6 by opening the conduit P1, the pressure receiving drive member D Rises, the upper surface thereof abuts against the adjusting screw b and is held at that position, and the operating member 6 that rises following the pressure-receiving drive member D stops is the low pressure setting. Then, at this time, the set pressure at the time of low pressure setting which is set at the stop position of the ascending operation of the operating member 6 is changed and adjusted as desired by the adjusting screw b in a state where the pressure reducing valve A is attached to the pipe. Become so.

Next, FIG. 8 shows another embodiment. In this embodiment, the pressure receiving drive member D provided in the pressurizing chamber K is a piston in which the pressure receiving drive member D is slidably fitted in the pressurizing chamber K, whereas a diaphragm is used in this embodiment. It is an example. In addition, this embodiment is a modification of the embodiment shown in FIG. 6, and the adjusting screw b is screwed into the ceiling wall of the pressurizing chamber K.

Since the rest of the configuration except these points is the same as that of the above-described respective embodiments, the components having the same effect are denoted by the same reference numerals and detailed description thereof will be omitted.

In this embodiment, when the pressurizing chamber K communicates with the atmosphere through the conduit P1 by controlling the valve V by the electromagnet S, the low pressure is set as shown in FIG. By communicating with the primary side through P2, it is possible to switch to the high pressure setting as shown in FIG. 9, and the setting pressure at the low pressure setting can be adjusted by the adjusting screw b. Is the same as.

[0041]

As described above, in the pressure reducing valve according to the present invention, the diaphragm 3 connected to the valve body 20 of the pressure reducing valve mechanism 2 is pushed toward the pressure sensitive chamber 14 side of the secondary pressure to set the pressure. The fulcrum side of the pressure reducing spring a that sets the secondary pressure is moved in the direction of the spring pressure of the pressure reducing spring a by the pressure receiving drive member D driven by the water pressure introduced from the primary side w, so that the set pressure becomes high. Since I am trying to switch between setting and low pressure setting, switch the water supply pressure to the water heater to high and low,
When constructing a hot water supply device that can take out high-pressure hot water while safely maintaining the pressure in the can of the water heater, one pressure reducing valve can switch between high and low water supply pressure. The cost can be reduced.

When applied to a pressure reducing relief valve having a relief valve mechanism incorporated in the pressure reducing valve, it is not necessary to provide a low pressure relief valve and a high pressure relief valve.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a conventional pressure reducing valve.

FIG. 2 is a vertical sectional front view of a pressure reducing valve according to the present invention.

FIG. 3 is an explanatory view of the operation of the above embodiment.

FIG. 4 is a vertical sectional front view of another embodiment of the above.

FIG. 5 is an explanatory view of the operation of the above embodiment.

FIG. 6 is a vertical sectional front view of still another embodiment of the same.

FIG. 7 is an explanatory view of the operation of the above embodiment.

FIG. 8 is a vertical sectional front view of still another embodiment of the same.

FIG. 9 is an explanatory view of the operation of the above embodiment.

[Explanation of symbols]

A ... pressure reducing valve, a ... pressure reducing spring, b ... adjusting screw, w ... primary side, y ... secondary side, D ... pressure receiving drive member, K ... pressurizing chamber, P1
P2 ... Pipe line, S ... Electromagnet, V ... Valve rod, ST ... Stopper, a-1 ... Low pressure setting spring, a-2 ... High pressure setting spring, 1 ... Valve box, 10 ... Inlet pipe, 11 ... Outlet Tube, 12 ... Partition wall, 13 ... Cylindrical part, 14 ... Pressure sensing chamber, 15 ... Spring case,
16 ... Check valve, 17 ... Vacuum breaking valve, 2 ... Pressure reducing valve mechanism, 2
0 ... Valve body, 21 ... Valve seat, 22 ... Valve shaft, 23 ... Balance valve, 3 ... Diaphragm, 30 ... Connecting screw, 4 ... Relief valve mechanism, 40 ... Valve body, 41 ... Relief port, 42 ... Valve seat, 43 ... Discharge pipe, 5 ... Spring, 6 ... Actuating member, 6a ... Collar part, 60 ... Spring support seat, 70 ... Block, 71 ... Restoring spring, 72 ... Communication passage.

Claims (3)

[Claims] 1. A pressure-reducing drive member provided so that a fulcrum side of a pressure-reducing spring that acts on a diaphragm connected to a valve body of a pressure-reducing valve mechanism to set a set pressure is driven by water pressure on the primary side. A pressure reducing valve that moves in the direction of the spring pressure to switch the set pressure between high pressure setting and low pressure setting. 2. A pressure reducing spring for setting a set pressure by acting on a diaphragm linked to a valve body of the pressure reducing valve mechanism is divided into two pressure reducing springs arranged in parallel, and one of the pressure reducing springs is used for the primary side water pressure. By the pressure receiving drive member provided to drive
A pressure reducing valve that moves in the direction of the spring pressure of the pressure reducing spring so that the set pressure is switched between high pressure setting and low pressure setting. 3. A pressure reducing spring a for setting a set pressure by acting on a diaphragm 3 connected to a valve body 20 of the pressure reducing valve mechanism 2.
The fulcrum side of is moved in the direction of the spring pressure of the decompression spring a by the pressure receiving drive member D provided so as to be driven by the water pressure on the primary side w so that the set pressure is switched between the high pressure setting and the low pressure setting. In the pressure reducing valve described above, the pressure receiving drive member D communicates with the primary side w in the valve box 1 via the pipe line P2 and the pipe line P2.
The pipe line P1 and the pipe line P2, which are stored in a pressurizing chamber K that communicates with the atmosphere via 1 and communicate with the pressurizing chamber K, are connected to the pressurizing chamber K by a V valve operated by an electromagnet S. A pressure reducing valve that is controlled to alternate and communicate with each other.