JPH0562766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to a vacuum evaporator, a vacuum concentrator, and a vacuum level control valve that has a self-control function to maintain a desired vacuum pressure when promoting distillation.

In order to maintain constant product quality in the above equipment,
Constant control of the vacuum pressure is an important requirement.

(2) Prior art Conventionally, in this type of vacuum pressure control device, a throttle is provided at the inlet of a vacuum pump for suction to change the suction cross-sectional area, and a PID system consisting of the opening of this throttle and a vacuum pressure gauge is installed. The pressure was controlled by the control.

(3) Problems to be solved by the present invention In the control system as described above, the response speed is extremely slow, making stable control difficult. The point is that it takes a long time to start and reach a stable state. Since it is necessary to reduce the gain, the motor rotates at an extremely low speed, which has the disadvantage that it is easily affected by unstable friction during opening and closing of the diaphragm, and deviations are likely to occur.

Furthermore, such a control system is very expensive, has a complicated structure and adjustment, and requires electricity and air to drive the regulating valve.

The technical problem of the present invention is to maintain the degree of vacuum accurately and stably without using a complicated control device, and to
The object of the present invention is to obtain a vacuum degree control valve that is inexpensive and has a simple structure.

(4) Means for solving the problem The technical means of the present invention taken to solve the above-mentioned technical problem is to form an inlet, a valve port, and an outlet in a valve casing, and to form a valve that faces the valve port. A valve body is arranged, a diaphragm is attached to the valve body, a valve chamber partitioned by the diaphragm is formed on the inlet side, and an adjustment spring is brought into contact with one side of the diaphragm. an energizing adjustment spring is disposed, the other end of the adjustment spring is connected to an adjustment screw, the adjustment screw is screwed into the valve housing, and the biasing spring is brought into contact with the other surface of the diaphragm inside the valve chamber. is arranged.

(5) Effect The inlet side of the valve of the present invention is connected to a device to create a vacuum, and the outlet side is connected to a vacuum pump, respectively, and suction is performed by the vacuum pump. By operating the adjustment screw and pulling up the diaphragm and the valve provided thereon, the valve port is opened and the fluid on the primary side is sucked into the secondary side. When the desired pressure on the primary side is reached, the diaphragm overcomes the force of the adjusting spring and deflects inward, causing the valve body to close the valve port and the suction to be relieved. As the primary pressure increases, the opening area of the valve port increases as the diaphragm is returned to its original position by the force of the adjustment spring. Repeat this below.

Any degree of vacuum can be easily obtained by operating this adjustment spring force.

(6) Effects of the invention The present invention produces the following unique effects.

Compared to conventional control systems that require PID operation, the desired degree of vacuum can be obtained very cheaply and easily. Furthermore, time delays are eliminated and responsiveness is improved.

Since the valve operates in balance with a diaphragm, the pressure on the primary side can be maintained constant regardless of changes in the degree of vacuum on the secondary side.

(7) Examples Examples showing specific examples of the technical means of the present invention will be described.

An inlet 2 and an outlet 3 are coaxially formed in a main body 1, and each is provided with a female thread for connecting a pipe. A valve seat 5 having a valve port 4 is screwed to the boundary wall between the inlet 2 and the outlet 3 via a gasket 6. The valve seat 5 is made of metal, and a rubber valve seat member 7 is adhesively bonded to the upper end thereof. A rubber diaphragm 9 is sandwiched between the main body 1 and the lid 8,
Tighten with cap nut 10, and connect main body 1 and diaphragm 9.
The valve chamber 11 is formed by the above. The valve body 12 is passed through the diaphragm 9 toward the inside of the valve chamber 11, and the washer 1
3 and 14 are sandwiched above and below and fixed with nuts 15.
A biasing spring 30 is disposed within the valve chamber 11 between the valve body 12 and the valve seat 5. An adjusting screw 16 is screwed into the upper part of the lid 8, and the lower end of the adjusting screw 16 and the upper end of the valve body 12 fixed to the diaphragm 9 are joined by an adjusting spring 17 under tension. A metal fitting 18 is inserted into a recess at the bottom of the adjusting screw 16 and locked with a snap spring 19 so that the adjusting spring 17 and the adjusting screw 16 can rotate freely with respect to each other. A lock nut 20 is screwed between the upper part of the lid 8 and the adjustment screw 16, and a communication port 21 with the atmosphere is opened in the lid 8.

The inlet 2 is connected to a device (not shown) that is desired to create a vacuum, and the outlet 3 is also connected to a vacuum generator (not shown). Adjust the diaphragm 9 by operating the adjusting screw 16.
and set the valve body 12 in the desired state.

At the beginning of operation, the pressure in the valve chamber 11 is still higher than the desired vacuum pressure, and the diaphragm 9 is
and is displaced upward by the biasing spring 30 to open the valve port 4. When the pressure inside the valve chamber 11 is reduced by the vacuum generator and approaches a desired vacuum pressure, the diaphragm 9 overcomes the spring force of the adjustment spring 17 and the biasing spring 30 and bends downward to close the valve port 4. and normally maintain this state of balance.

At this point, when the adjusting screw 16 is pulled up further, the valve port 4
This makes it difficult for the valve port 4 to close, allowing the primary side set vacuum pressure to be set low.On the other hand, when the adjusting screw 16 is lowered, the valve port 4 becomes easier to close, and the set vacuum pressure can be set higher.

Vacuum pressure 0 to 760mm without biasing spring 30
If you try to select an adjustment spring 17 that can set the Hg range, you will have to use a spring with a very large spring constant near 0 mmHg, and if you use this spring, you will not be able to set the pressure in the range of 500 to 760 mmHg. The disadvantage is that it is difficult to make fine adjustments. Conversely
If a spring corresponding to a pressure setting of about 500 to 760 mmHg is selected, it will be difficult to set a pressure of about 0 to 200 mmHg, but according to this embodiment, the pressure can be adjusted by interposing the biasing spring 30. The adjustment spring 17 with a small spring constant allows the pressure to be set up to a high vacuum range.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the vacuum degree regulating valve of the present invention. 4: Valve port, 8: Lid, 9: Diaphragm, 11:
Valve chamber, 12: Valve body, 16: Adjustment screw, 17: Adjustment spring, 30: Biasing spring.

Claims (1)

[Claims] 1. An inlet, a valve port, and an outlet are formed in a valve housing, a valve body is arranged opposite to the valve port, a diaphragm is attached to the valve body, and a valve chamber partitioned by the diaphragm is formed on the inlet side; In a device in which an adjustment spring is brought into contact with one surface of a diaphragm, the adjustment spring under tension is arranged outside the valve chamber of the diaphragm, the other surface of the adjustment spring is connected to an adjustment screw, and the adjustment screw is connected to the valve housing. A vacuum adjustment valve that is screwed into the body and has a biasing spring that comes into contact with the other surface of the diaphragm inside the valve chamber.