JPH0242155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for supplying liquid from a main valve device to a liquid tank;
This invention relates to a constant liquid level control device in which stoppage is controlled by a pilot valve device that opens and closes a pilot valve seat in response to changes in the liquid level in a liquid tank.

This type of constant liquid level control device is conventionally known.
Its structure consists of a main valve device 1, a pilot valve device 2, and a liquid tank 3, as shown in FIG. Main valve device 1
A main flow path 5 penetrates inside the valve housing 4, and a main valve seat 6 provided in the main flow path connects the upstream main flow path 5A connected to a liquid supply source (not shown) and the liquid tank 3 via a pipe or the like. It is divided into an open downstream main flow path 5B, and a main valve 7 is disposed corresponding to the main valve seat 6 thereof. A flexible membrane 8 made of an elastic member is connected to the main valve 7, and a main valve operating fluid chamber 10 is formed between the flexible membrane 8 and the upper lid 9, and the main valve operating fluid chamber 10 is located upstream. Side main channel 5
It is connected to A by a bypass channel 11, and a drain channel 12 is opened.

In the pilot valve device 2, a pilot passage 14 passes through a pilot valve main body 13, and an inflow side pilot passage 14A, which is divided by a pilot valve seat 15 provided in the pilot passage 14, communicates with the drain passage 12. The outflow side pilot flow path 14B is opened to the liquid tank 3.

A pilot valve 16 is arranged corresponding to the pilot valve seat 15, and the pilot valve controls the opening and closing of the pilot valve seat 15 using a float 17 and a float arm 19 that move in synchronization with the liquid level of the liquid tank 3.

18 is a consumption port for consuming the liquid in the liquid tank 3 to the outside. According to such a conventional constant liquid level control device, the opening/closing characteristics of the pilot valve 16 and the main valve 7
The opening and closing characteristics are as shown in FIG.

That is, when the liquid level in the liquid tank 3 is at a constant level A, the float 17 is in the position shown in FIG. 15 to close the pilot valve seat 15 and drain the drain passage 12.
is isolated from the atmosphere.

Therefore, the main valve operating liquid chamber 10 of the main valve device 1
The liquid in the main flow path 5A on the upstream side flows into the bypass flow path 1.
1, and the inflowing liquid is hermetically stored in the main valve operating liquid chamber 10, so the main valve 7 is moved to the main valve seat by the difference in pressure between the upper and lower sides of the main valve 7 and the flexible membrane 8. 6 to block and hold the main flow path 5.

Next, when the liquid in the liquid tank 3 is consumed and reduced at the consumption port 18 and the liquid level drops, the float 17 moves synchronously with the drop in the liquid level, and the float arm 19
This rotation gradually causes the pilot valve 16 to open the pilot valve seat 15, and when the liquid level drops to B, the pilot valve seat 15 is fully opened. do.

During this process of lowering the liquid level from A to B, the pilot valve 16 is in a half-open state, and the liquid in the main valve operating liquid chamber 10 of the main valve device 1 is drained through the drain path 12 and the pilot flow path 14 to the liquid tank 3. The pressure inside the main valve actuating liquid chamber 10 is returned to atmospheric pressure and the biasing force in the closing direction of the main valve 7 is reduced. The main valve 7 gradually opens by decreasing the biasing force in the closing direction, and the liquid level C
It is fully opened when the liquid level D has further decreased from 1, and the main flow path 5 is opened to automatically supply liquid into the liquid tank 3.

Further, when the liquid level rises from the low liquid level B due to an increase in the liquid in the liquid tank 3, the float 17 moves synchronously with the rise in the liquid level, and the float arm 19 moves counterclockwise in the figure. The pilot valve 16 gradually closes the pilot valve seat 15 according to this rotation, and when the liquid level rises to A, the pilot valve seat 15 is completely closed.

Even when the liquid level rises, the pilot valve 16 is in a half-open state in the process of rising from liquid level B to liquid level A, similar to when the liquid level is falling, and the main valve operating liquid chamber 10
The liquid pressure is gradually accumulated in the main valve operating liquid chamber 10 by gradually restricting the release of liquid from the inside to the liquid tank 3, and the biasing force in the closing direction of the main valve 7 is increased. In this state, the main valve 7 also gradually closes, and the liquid level C
The main valve seat 6 is closed, and the supply of liquid from the main flow path 5 to the liquid tank 3 is stopped. According to the conventional constant liquid level control device that performs this function, the liquid level control device controls the liquid level of the liquid tank 3 depending on the balance between the amount of liquid supplied to the liquid tank 3 and the consumption amount of the liquid in the liquid tank 3.
When the liquid level within the chamber is maintained stably between C and D in Figure 2, the main valve 7 becomes a half-open state, and the speed of the liquid flowing through the main valve seat 6 increases, causing the sound of flowing water and causing a long period of time. This is undesirable as it causes noise over a long period of time.

When the main valve 7 is in a half-open state, the main valve 7 and the main valve seat 6
Since the opening degree between the main valve seat and the main valve seat is a minute opening degree, cavitation erosion occurs in the main valve seat portion, which is undesirable, especially when high-pressure liquid is used.

When the pilot valve 16 is half open, the liquid tank 3
When the liquid level in the main valve device 1 ripples due to the water discharged from the main valve device 1, the float 17 moves up and down due to the change in the liquid level due to the ripples, and the opening degree of the pilot valve 16 changes. 7 continuously repeats the opening and closing movement, which may cause the main valve 7 to fluctuate in the future, causing vibration in the piping system, which is undesirable.

As shown in FIG. 2, when the liquid level reaches C during the liquid level rising process, the pilot valve 16 is half open and the main valve 7 is fully closed.

During the liquid level rising process to liquid level C-A,
Liquid is supplied into the liquid tank 3 only from the pilot valve 16, and this supply amount is an extremely small flow rate compared to the supply amount from the main valve 7. Liquid flows into.

Therefore, the sound of running water is generated over a long period of time, causing undesirable noise.

Since the pilot valve 16 is opened half-open, cavitation erosion occurs on the pilot valve seat 15, which is undesirable as described above.

Since the main valve 7 opens and closes in an extremely narrow liquid level range (for example, between liquid levels C and D) of the pilot valve 16, it is difficult to prevent the consumption of a small amount of liquid, especially when directly supplying water to an elevated water tank. The main valve 7 operates due to changes in the liquid level, which increases the frequency of operation of the main valve 7, which causes problems such as wear of the main valve seat 6 and fatigue of the flexible membrane 8 during long-term use. It was hot.

The constant liquid level control device of the present invention has been developed in view of the above problems, and has a pilot valve device.
a self-closing pilot valve that is biased to close the pilot valve seat by liquid pressure in the inlet pilot flow path; a first float arm that is rotatably supported at one end and moves synchronously with the float; A connecting rod that swings synchronously with the first float arm, and a guide that is arranged in correspondence with a restriction section provided on the connecting rod, can only move in a certain direction on the connecting rod, and is pressed against the first spring restriction section. a ring, a pilot valve rod that moves synchronously with the pilot valve, and a length that is rotatably supported at one end, moves synchronously with the guide ring, and has play in the opening/closing movement direction of the pilot valve rod and the pilot valve. A second float arm is engaged through the hole, one end of which is engaged with the pilot valve rod, and the other end of which is engaged with the second float arm to apply a force in the opening direction to the pilot valve. The spring includes a second spring, and the spring force of the second spring is set to be weaker than the spring force of the first spring.

According to such a constant liquid level control device, when a high liquid level is formed in the liquid tank, both the pilot valve and the main valve hold their respective valve seats, and the liquid level changes from the high liquid level to the low liquid level. Both the pilot valve and the main valve keep their respective valve seats closed even when the liquid level drops. When the liquid level continues to fall and reaches the set low liquid level, the pilot valve immediately opens its pilot valve seat, which in turn causes the main valve to also open its main valve seat, allowing liquid to flow into the liquid tank. Let it flow. When the liquid level gradually rises from the low liquid level due to this replenishment, the pilot valve gradually closes the pilot valve seat, and as soon as the liquid level reaches the high liquid level, the main valve seat is immediately closed by the main valve. As a result, a constant high liquid level is formed and maintained.
An embodiment of the present invention will be described below with reference to FIG.
Since the main valve device 1 and the liquid tank 3 have the same structure as the conventional one, the same reference numerals will be used and the explanation will be omitted, and the pilot valve device P will be explained.

Reference numeral 20 denotes a pilot valve main body through which a pilot passage 21 passes, and is divided into an inlet pilot passage 21A and an outlet pilot passage 21B by a pilot valve seat 22 provided in the passage. 21A is the main valve operating liquid chamber 1 of the main valve device 1
The outflow side pilot flow path 21B is connected to the liquid drain path 12 branching from 0, and communicates with the liquid tank 3 so as to open thereto.

Valve rod support hole 2 bored in the pilot valve body 20
A pilot valve rod 24 is movably inserted into the valve rod 3, and an inflow side pilot flow path 21A is provided at the end of the valve rod.
A self-closing pilot valve 25 is disposed which is biased to close the pilot valve seat 22 in response to the liquid pressure within.

The float 17 placed in the liquid tank 3 is fixed to a first float arm 27 that is rotatably supported by a first support shaft 26 provided on the pilot valve body 20. A connecting rod 29 is swingably connected to the second support shaft 28 .

A regulating portion 30 such as a retaining ring is fixedly provided on the second support shaft 28 side of the connecting rod 29, and can move on the connecting rod 29 corresponding to the restricting portion 30, and the connecting shaft 31 is provided to protrude outward. The guide ring 32 is slidably disposed, and spring guides 33, 33 that can move on the connecting rod 29 are disposed in opposition to the guide ring 32, and a first spring guide is disposed between the two spring guides 33, 33. 34 is contracted, and the end of the connecting rod 29 is fixed with a lock nut 35.

The connecting rod 29 and the pilot valve rod 24 are connected by a second float arm 36 whose one end is rotatably supported, and the first and second float arms 27, 3
6. Opening/closing operation part S by pilot valve lever 24, etc.
form.

The second float arm 36 has one end rotatably supported by a support shaft 37 provided on the pilot valve body 20, and has a length with a certain amount of play in the opening/closing direction of the pilot valve rod 24 (horizontal direction in the figure). A hole 38 is bored and a connecting hole 39 is formed near the end of the hole 38.
to be drilled.

Then, insert the connecting shaft 40 protruding from the pilot valve rod 24 into the elongated hole 38, and connect the pilot valve rod 24.
The connecting shaft 31 of the guide ring 32, which is movably arranged on the connecting rod 29 and is engaged with a certain play a1, a2 in the direction of opening and closing movement of the pilot valve rod, is fitted into the connecting hole 39, and then the pilot valve rod 24, the second float arm 36, the connecting rod 29, and the first float arm 27 are pivotally connected.

Spring guides 42, 42 that can slide on the pilot valve rod 24 are provided corresponding to the retaining ring 41 fixed to the pilot valve rod 24 and the side surface 36A of the second float arm 36, and the spring of the first spring 34 is disposed between them. Second spring 43 weaker than the force
are arranged in a compressed manner, and the spring force of the second spring 43 biases the pilot valve 25 in the opening direction.

Next, its operation will be explained with reference to FIG. 3 and FIG. 4 showing the main valve opening/closing characteristics and the pilot valve opening/closing characteristics.

When the liquid level in the liquid tank 3 forms the water stop surface A, the float 17 is in the position shown in FIG. In response, it is pressed against the pilot valve seat 22 with a sufficiently strong pressing force F1, and the pilot valve 25 is reliably kept closed.

Therefore, the main valve operating liquid chamber 10 of the main valve device 1
The liquid pressure in the main flow path 5A on the upstream side is accumulated inside, and the main valve 7 closes the main valve seat 6 and blocks the main flow path 5 due to the vertical pressure difference between the main valve 7 and the flexible membrane 8. It is to be held as such.

In this state, the pilot valve lever 24
A connecting shaft 40 provided in the second float arm 36 is engaged in a long hole 38 formed in the second float arm 36 with respective plays a1 and a2 that allow the opening and closing directions of the pilot valve 25.

Next, when the liquid level drops from water stop level A to A,
As the liquid level decreases, the float 17 and the first float arm 27 move counterclockwise about the first support shaft 26 as a fulcrum. At this time, the pilot valve 25 is receiving a strong biasing force F1 in the closing direction as described above, and the first spring 34, which has a stronger spring force than the second spring 43, connects the guide ring 32 on the connecting rod 29 and the clock nut 35. Spring guide 33 between
33, the second float arm 36 also supports the second spring 4 with the support shaft 37 as a fulcrum due to the movement of the first float arm 27.
3, rotate counterclockwise while pressing 3, move by the left side play a1 of the elongated hole 38, and move the left side part 3 of the elongated hole 38.
8A is in contact with the connecting shaft 40 of the pilot valve lever 24. The second spring 43 receives the counterclockwise movement of the second float arm 36 via its side surface 36A, and increases the biasing force 1 in the opening direction against the pilot valve 25, but increases the biasing force F1 in the closing direction of the pilot valve 25. On the other hand, if the spring force is sufficiently weak, the pilot valve 25 will not open.

Therefore, when the liquid level drops from A to A, the pilot valve 25 is still in contact with the pilot valve seat 22.
The main valve 7 also holds the main valve seat 6 in a closed state.

Next, when the liquid level in the liquid tank 3 further decreases from A to B, the float 17 and the first float arm 27 further move counterclockwise about the first support shaft 26 as a fulcrum.

At this time, the closing direction biasing force F1 of the pilot valve 25
is sufficiently strong so that the first float arm 27
For the counterclockwise movement of , the guide ring 32 moves on the connecting rod 29.
is allowed to move by contracting the first spring 34, and the second float arm 36 does not move even when the first float arm 27 moves counterclockwise.

At this time, the biasing force in the opening direction for the pilot valve 25 is due to the spring force f2a increased due to the contraction of the first spring 34 and the second spring 43.
The resultant force of spring force f1 acts, but f2a+f1<F1
By setting as follows, the pilot valve 25 can still keep the pilot valve seat 22 closed, and the main valve 7 can also keep the main valve seat 6 closed.

Next, when the liquid level in the liquid tank 3 further decreases from the mouth to B, the float 17 and the first float arm 27 further rotate counterclockwise about the first support shaft 26 as a fulcrum.

At this time, the counterclockwise movement of the first float arm 27 is performed by moving the guide ring 32 on the connecting rod 29 in the same manner as described above.
is allowed by further compressing and moving the first spring 34. Pilot valve 2
The biasing force in the opening direction against 5 is the resultant force of the sufficiently increased spring force f2B of the first spring 34 and the spring force f1 of the second spring 43 due to the further reduction of the first spring 34, so that the liquid level B
By setting the force relationship such that f2b+f1>F1, the second float arm 36 receives this spring force and rotates counterclockwise about the support shaft 37. This rotation is carried out from the left side portion 38A of the long hole 38 of the second float arm 36 to the pilot valve rod 24.
The pilot valve lever 24 is moved to the right in the figure to open the pilot valve 25 slightly from the pilot valve seat 22. Then, by opening the pilot valve 25, the liquid in the drain passage 12 flows out from the inflow pilot passage 21A to the outflow pilot passage 21B, so the liquid pressure accumulated in the inflow pilot passage 21A decreases significantly. The pilot valve rod 24 suddenly releases the pilot valve seat 2 due to the spring force of the first spring 34 which had stored spring force and the opening force of the second spring 43.
Open 2. Therefore, a large amount of the liquid stored in the main valve operating liquid chamber 10 of the main valve device 1 is released, and the main valve 7 is also immediately activated due to the vertical pressure difference between the main valve 7 and the flexible membrane 8. The main valve seat 6 can be opened, and liquid is supplied from the main valve device 1 into the liquid tank 3.
It should be noted that the time required for the pilot valve 25 to go from a slight opening to a full opening is extremely quick, and the pilot valve 25 does not remain half open during the opening.

When the pilot valve 25 is fully open, the connecting shaft 4 in the long hole 38 of the second plate arm 36 is opened.
0, the second spring 43 applies a biasing force in the opening direction to the pilot valve 25, so that the elongated hole 38 is opened.
It abuts on the right side portion 38B of.

Next, a description will be given of the case where the liquid level in the liquid tank 3 rises from a state where it has fallen to B upon receiving the supply of liquid from the main valve device 1.

When the liquid level rises from the liquid level B, the float 17 and the first float arm 27 move clockwise about the first support shaft 26 as a fulcrum. Then, the clockwise movement of the first float arm 27 is transmitted from the second support shaft 28 to the connecting rod 29, and the movement of the connecting rod 29 is transmitted from the regulating part 30, the guide ring 32, and the connecting shaft 31 to the second float arm 36. transmitted to the second float arm 36
is rotated clockwise synchronously by the movement of the first float arm 27.

The second float arm 36 rotates from the right side portion 38B of the elongated hole 38 to the connecting shaft 4 of the pilot valve rod 24.
0, the pilot valve lever 24 is moved to the left in the figure, and the pilot valve 25 is gradually moved toward the pilot valve seat 22.

Note that in this liquid level rising range, the opening degree of the pilot valve 25 gradually decreases;
5 has not yet reached the slight opening degree, the liquid pressure in the main valve operating liquid chamber 10 has not accumulated enough pressure to close the main valve 7, so the main valve 7 of the main valve device 1 is still closed. Keep open.

When the liquid level further rises from the above state and reaches A, the pilot valve 25 moves further in the closing direction as described above due to the clockwise rotation of the float 17, and the pilot valve 25 and the pilot valve seat 22 are sufficiently close to each other, resulting in a minute opening.

Then, as the outflow of liquid from the outflow side pilot flow path 21B decreases, the liquid pressure in the inflow side pilot flow path 21B rapidly becomes sufficiently large compared to the biasing force f1 of the second spring 43 in the pilot valve opening direction. This liquid pressure exerts a strong closing force on the self-closing pilot valve 25.

Then, the pilot valve rod 24, which has received this sufficiently large biasing force in the closing direction, resists the biasing force f1 in the pilot valve opening direction of the second spring 43 and moves the connecting shaft 40.
moves from the right side portion 38B of the elongated hole 38 to the middle portion of the elongated hole 38, and presses the pilot valve 25 against the pilot valve seat 22.
2 immediately occluded.

Therefore, the main valve operating liquid chamber 10, whose drain passage 12 is cut off from the atmosphere, immediately closes the main valve seat 6 due to the pressure difference between the main valve 7 and the flexible membrane 8, as described above. The supply of liquid from the valve device 1 to the liquid tank 3 is stopped.

The constant liquid level control device according to the present invention has the following effects.

The opening degree of the main valve 7 becomes half-open, and the velocity of the fluid flowing through the main valve seat 6 increases, causing the sound of running water, which can completely eliminate the noise that occurs when high-pressure liquid is used. Cavitation erosion of the main valve seat 6 can be completely eliminated, allowing stable use over a long period of time even when using liquid at any liquid pressure.

In the pilot valve 25 as well, since the pilot valve seat 22 is no longer in a half-open state when the liquid level is low, the problem of running water noise cavitation erosion can be completely eliminated as in the main valve 7. Also, when the liquid level rises, the pilot valve seat 22 will be in a half-open state, but if the degree of opening becomes very small and the flow velocity at the pilot valve seat 22 increases and the liquid pressure rises, the pressure will increase. Since the pilot valve 25 closes immediately, the sound of running water and cavitation erosion can be significantly improved compared to conventional valves.

When the liquid level drops or rises, the main valve 7 and the pilot valve 25 can be opened and closed synchronously.
Since the main valve 7 is closed after the pilot valve 25 is closed, when the liquid level reaches the water stop level A, the supply of liquid from either the main valve 7 or the pilot valve 25 can be immediately stopped, unlike the conventional method. The problem that liquid is supplied from the pilot valve 25 for a long time and noise is generated due to the sound of running water can be completely eliminated.

The main valve 7 is controlled to open and close only at the liquid levels A and B of the pilot valve 25, and the level difference between the liquid levels can be set much larger than that of conventional valves, especially when directly supplying water to an elevated water tank, etc. Even if the liquid level changes due to the consumption of a small amount of liquid, the main valve device 1 will not operate, and the frequency of operation can be kept low, reducing wear and flexibility of the main valve 7, main valve seat 6, etc. The fatigue durability of the membrane 8 is significantly improved, and stable quality can be maintained over a long period of time.

Even when the liquid surface is rippled, the level difference is made sufficiently large, so the main valve 7 no longer opens and closes continuously, which causes the main valve 7 to fluctuate, causing vibrations and noise in piping, etc. There's nothing to do.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a conventional constant liquid level control device. FIG. 2 is a diagram showing the main valve opening/closing characteristics and pilot valve opening/closing characteristics of a conventional constant liquid level control device. FIG. FIG. 4 is a longitudinal cross-sectional view of the main part of the pilot valve device of the liquid level control device, and FIG. 4 is a diagram showing the main valve opening/closing characteristics and the pilot valve opening/closing characteristics of the same example. 1... Main valve device, 3... Liquid tank, 17... Float,
22... Pilot valve seat, 24... Pilot valve lever, 25... Pilot valve, 27... First float arm, 30... Control unit, 32... Guide ring, 3
4...first spring, 36...second float arm, 43...second spring.

Claims (1)

[Claims] 1 A pilot valve device that opens and closes the pilot valve seat in response to changes in the liquid level in the liquid tank, and a main valve that opens and closes the main valve seat in response to opening and closing of the pilot valve device to supply and stop liquid to the liquid tank. In a constant liquid level control device consisting of a valve device, the pilot valve device is a self-closing type pilot valve that is biased to close the pilot valve seat by the liquid pressure in the inflow side pilot flow path, and one end of which is rotatable. A first float arm that is pivoted on the body and moves synchronously with the float; a connecting rod that swings synchronously with the first float arm; A guide ring that can move only in a certain direction and is pressed against the first spring regulating portion, a pilot valve lever that moves synchronously with the pilot valve, and a pilot valve lever that is rotatably fixed at one end and moves synchronously with the guide ring. At the same time, a second float arm is connected to the pilot valve lever through an elongated hole that has play in the direction of opening and closing movement of the pilot valve, and one end is locked to the pilot valve rod and the other end is connected to the second float arm. a second spring that is stopped and applies a force in the opening direction to the pilot valve;
A constant liquid level control device configured as follows, and the spring force of the second spring is set to be weaker than the spring force of the first spring.