JPS6025016Y2 - Diaphragm type switching valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a diaphragm type switching valve with a built-in exhaust throttle mechanism.

One of the switching and sampling valves used in process gas chromatographs (hereinafter abbreviated as PGC) is the diaphragm type switching valve1.
The explanation will be given with reference to FIGS. 2a"-'c showing the structure and FIGS. 3a-'c explaining the operation.

In each figure, 9 is a switching valve, 1 to 8 are its respective ports, 10 is a diaphragm, 11 and 12 are driving piping connections, and 13 is a pressure source for instrumentation such as air pressure;
4 is a four-way solenoid valve, 15 is a throttle, and 16 is a pipe.

In FIG. 2, 17 is a coupling screw, 18 is a disc spring, 19 is an upper body, and 20 is a lower body.

Further, FIG. 3 shows the switching valve 9 developed along each port +1 to +8, that is, FIG. , C indicates a state in the middle of switching.

In this switching valve 9, eight ports 1 to 8 are concentrically opened in the upper body 19, and the tip of each port is bifurcated and opened at equal intervals on the concentric circle.
A hemispherical valve chamber is opened corresponding to each pair of branch ports of each adjacent port, and every other valve chamber is communicated with each other via a communication passage to connect to the piping connection ports 11 and 12.
The diaphragm 10 is sandwiched between the upper and lower bodies 19 and 20.

An example of the operation of such a switching valve 9 will be explained below.

Now, in the PGC, the sample gas (carrier gas) is at odd numbered port 1. 3. It has been flowing in since 5.7,
Due to the action of the four-way solenoid valve 14, valve driving pressure (hereinafter simply referred to as driving pressure) is applied to the upper piping connection port 11 as shown in Fig. 3a.
It is assumed that the lower piping connection port 12 is opened to the atmosphere.

In this state, the diaphragm 10 closes the branch ports of adjacent ports in the valve chamber where driving pressure is applied, but in the valve chamber where driving pressure is not applied, the diaphragm 10 is pushed away by the pressure of the sample gas, so each adjacent port The branch ports of are in communication, and the sample gas is 1→2, 3→4, 5→
6, 7→8, the signal flows from the odd-numbered port to the even-numbered port on the right in FIG. 3a.

On the other hand, the switching operation is performed by operating the four-way solenoid valve 14 to open the upper piping connection port 11 to the atmosphere and applying driving pressure to the lower piping connection port 12, as shown in FIG.

As a result, the state of the diaphragm 10 changes from a to b, and the diaphragm 10 in the valve chamber to which no driving pressure is applied
is pushed away by the sample gas, and the sample gas changes from 1 to 8
, 3→2, 5→4.7→6, the flow is switched from the odd numbered port to the adjacent even numbered port on the left in FIG.

By the way, a feature of the diaphragm type switching valve 9 in use is that during switching from a to b or from b to a in FIG. 3, communication between all ports is closed.

It is necessary to ensure state C. This is because, for example, even if the four-way solenoid valve 14 switches instantaneously, there is a delay in the propagation of driving pressure in the piping 16 between the solenoid valve 14 and the switching valve 9, so all ports on the switching valve 9 side are temporarily closed. This is to prevent the sample gas from flowing to either the left or right port, for example, 8←1←2, even if it is temporarily opened.

Conventionally, in order to create the state shown in Fig. 3C, a restriction 15 is inserted into the exhaust part of the four-way solenoid valve 14 as shown in Fig. 1, and a time delay is required to open the pipe connections 11 and 12 to the atmosphere. I was trying to keep it.

In FIG. 1, solid line arrows indicate the pressure direction that produces the state shown in FIG. 3A, and broken line arrows indicate the pressure direction that produces the state shown in FIG. 3A.

However, the conventional technique in which the throttle 15 is attached externally to throttle the exhaust gas on the four-way solenoid valve 14 side has the following disadvantages.

In other words, since the pressure propagation delay changes depending on the length of the pipe 16 between the four-way solenoid valve 14 and the switching valve 9, the valve characteristics, that is, the state shown in FIG. It will change.

Further, when a plurality of four-way solenoid valves 14 share one throttle 15 and a plurality of switching valves 9 are used in the PGC, the characteristics of each switching valve 9 cannot be freely controlled.

Therefore, the purpose of the present invention is to provide a switching valve that can control the valve characteristic circle with the diaphragm type switching valve itself, and for this purpose, the switching valve itself incorporates a mechanism that applies a restriction only during exhaust.

Hereinafter, the present invention will be explained with reference to FIGS. 4 and 5.

FIG. 4 shows one implementation of the present invention.

However, since the switching valve of this embodiment is the same as the conventional technology shown in FIGS. 2 and 3 except for the piping connection port,
The figure shows only the piping connection port.

In FIG. 4, reference numerals 11 and 12 are upper and lower piping connection ports, respectively, which connect O-
It is attached via a ring 21.

The end of the communication passage is formed to have a slightly larger diameter to form a valve chamber 22, and a spring 23 and a piston 24 with a throttle hole are installed in this valve chamber 22.

The piston 24 is constantly pressed by the spring 23 toward the pipe connection port 11.12.

Note that 25 is an O-ring.

Suppose now that driving pressure is applied to the upper piping connection port 11 and the lower piping connection port 12 is open to the atmosphere.

On the piping connection port 11 side to which the driving pressure is applied, the piston 24 inside thereof is pushed by the driving pressure, and the internal pressure rises, resulting in the diaphragm position as shown in FIG. 3a.

Note that when the internal pressure becomes equal to the driving pressure, the piston 24 is pressed against the O-ring 25 by the spring 23 and closes the piping connection port 11.

Assume that from this switching state, driving pressure is applied to the lower piping connection port 12, and the upper piping connection port 11 becomes open to the atmosphere.

On the lower piping connection port 12 side, the piston 24 is pushed by the driving pressure, so the internal pressure rises as described above, and this internal pressure pushes up the diaphragm 10, which was lowered in Figure 3a, and closes the port in that area. Closed.

On the other hand, the upper piping connection port 11 side is opened to the atmosphere and the internal pressure is discharged through the throttle hole 24a of the piston 24, so it takes time for the internal pressure to become equal to the atmospheric pressure, and this time lag occurs. In the middle of the process, the diaphragm 10 is temporarily pushed up while the internal pressure is high to some extent.

Therefore, the state shown in FIG. 3C is temporarily created, and then the switching state shown in FIG. 3C is established.

The time period for which the state shown in FIG. 3C is maintained can be freely selected by changing the diameter or length of the throttle hole 24a formed in the piston 24.

Figures 5a and 5c show another embodiment, in which another member is used in place of the piston in Figure 4.

The example shown in FIG. 5a is an example using a ball 26, and the throttling effect is obtained by a groove 27 provided in the ball receiver of the pipe connection port 11 (or 12).

Figure 5 is an example using a needle valve 28, and the throttling effect is achieved by making the tip of the needle valve 28 slightly smaller in diameter, and
1 (or 12).

FIG. 5C shows an example using a reed valve 30, and the throttling effect is obtained by a throttling hole 30a made in the reed valve 30.

Note that when using the reed valve 30, a spring is not required, and when driving pressure is applied, the reed valve 30 is
is away from the piping connection port 11 (or 12) as shown in the diagram,
If it is opened to the atmosphere, it will close up naturally due to the differential pressure.

As described above in detail with the embodiments, according to the present invention, the diaphragm type switching valve itself has a built-in mechanism that throttles only during exhaust, that is, a check valve with a throttle.

Therefore, the time for all ports to close can be secured without any modification to the electromagnetic valve side.

Further, since the time for closing all boats can be adjusted for each switching valve, each switching valve can be operated optimally.

Furthermore, the time for all boats to be closed can be set regardless of the length of the piping between the switching valve and the solenoid valve.

[Brief explanation of drawings]

1 to 3 relate to the prior art; FIG. 1 is a piping diagram, FIG. Figure a ” c
2 is a developed cross-sectional view taken along the line A--A in FIG. 2a for explaining the operation. Figure 4 is a sectional view of the main parts of an embodiment of the present invention, Figure 5a
"c is a sectional view showing another embodiment. In the drawing, 1 to 8 are ports, 9 is a switching valve, 10 is a diaphragm, 11 and 12 are piping connection ports, 13 is a pressure source, 1
4 is a four-way solenoid valve, 15 is a throttle, 16 is piping, 17 is a coupling screw, 18 is a disc spring, 19 is an upper body, 20 is a lower body, 21 and 25 are O-rings, 22 is a valve chamber, 23 is a Spring, 24 is a piston, 24a is its throttle hole, 26
is a ball, 27 is a throttle groove, 28 is a needle valve, 29
30 is a reed valve, and 30a is its throttle hole.

Claims (1)

[Scope of utility model registration request] In a diaphragm type switching valve that switches communication between ports by a diaphragm connected to two series of communication passages that alternately pressurize and release pressure, each piping connection part of the communication passage connected to the pressure switching device is A diaphragm type switching valve characterized by a built-in check valve with a throttle that allows pressure to pass without load while restricting exhaust pressure.