JPH04160276A - Flow passage valve - Google Patents

Abstract

PURPOSE:To prevent to transmit a sudden high pressure to the downstream side by dividing a valve chest into the upstream side and the downstream side by a diaphragm, and displacing the diaphragm to shut the tip of the main passage at the downstream side when a high pressure is applied suddenly to the main passage at the upstream side of both valve chests. CONSTITUTION:A valve chest 4 is divided into the upstream side chest 4a and the downstream side chest 4b by a diaphragm 6 provided crossing the valve chest 4. And the tip of the main flow passage 2a at the upstream side is led to the valve chest 4a at the upstream side, while the tip of the main flow passage 2b at the downstream side is led to the valve chest 4b at the downstream side. The tips of both main flow passages 2a and 2b are close to the diaphragm 6, and opposed each other at both sides of the diaphragm 6. The diaphragm 6 furnishes apertures 10 to pass the gas with no resistance opened at the area other than the area where the tips of both passages 2a and 2b are opposed. When a high pressure is applied from the upstream side suddenly, the diaphragm 6 is displaced by receiving the force of the gas, a rubber sheet 8 is attached closely to the tip of the downstream side main passage 2b, and the tip of the main flow passage 2b at the downstream side is closed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention applies
The present invention relates to a flow path valve suitable for use in combination with a flow meter when flowing fluid at a precisely controlled flow rate, or for use in preventing a large amount of fluid from flowing.

(Prior art) When a carrier gas is flowed at a precise flow rate in a gas chromatograph, the flowmeter is used to measure the flow rate by providing a resistance in the carrier gas flow path and measuring the differential pressure across the resistance. something is being used. A sensor for measuring differential pressure uses, for example, a diaphragm.

(Problems to be Solved by the Invention) In order to accurately measure the flow rate, a highly sensitive sensor must be used. Highly sensitive sensors will be damaged if high pressure is applied suddenly. This is because the pressure difference before and after the flow path resistance temporarily becomes too large.

If only to prevent damage to the sensor, it is sufficient to provide a resistor upstream of the sensor. However, if a resistor is provided upstream, a pressure drop will occur in that area, making it impossible to obtain the desired pressure.

In order to solve this problem, the present invention is designed to prevent fluid from flowing at a predetermined flow rate without acting as resistance to the flow path during normal operation, but when high pressure is suddenly applied from the upstream side. To provide a flow path valve capable of protecting a sensor on the downstream side and preventing a large amount of fluid from flowing downstream by preventing sudden high pressure from being transmitted to the downstream side when applied to the downstream side. The purpose is to

(Means for Solving the Problems) In the flow path valve of the present invention, the valve chamber is divided into an upstream side and a downstream side by a diaphragm, and the leading end of the main flow path is guided to each of the two divided valve chambers. The tip of the main flow path is close to the diaphragm such that the diaphragm can close the tip of the downstream main flow path when a sudden high pressure is applied to the upstream main flow path;
In addition, the diaphragm is provided with an opening that allows fluid to pass through with almost no resistance to an area other than the area where the two main flow channels face each other, and the main flow channel in the downstream valve chamber is provided with an opening. A channel is formed in the side wall to allow fluid to pass through with resistance.

(Function) During normal operation, fluid flowing through the upstream main channel enters the upstream valve chamber from the tip of the upstream main channel, passes through the opening of the diaphragm, enters the downstream valve chamber, and enters the downstream main channel. It enters the downstream main channel from the tip and flows. In this case, the resistance is approximately O even if the flow path valve is present.

When high pressure is suddenly applied to the upstream main flow path, force acts on the diaphragm, causing the diaphragm to displace and close the tip of the downstream main flow path. At this time, the fluid flowing through the upstream main flow path enters the upstream valve chamber from the tip of the upstream main flow path, passes through the opening of the diaphragm, enters the downstream valve chamber, and enters the flow path on the side wall of the downstream main flow path. through which it enters the downstream main channel and flows. The flow path on the side wall of the downstream main flow path is set to have resistance, so sudden high pressure is not transmitted to the downstream side where sensors etc. are installed, and the fluid gradually flows out downstream. go. Then, as time passes, the pressure difference between the upstream and downstream sides of the diaphragm becomes smaller, and eventually the diaphragm separates from the tip of the downstream main channel, and the resistance returns to almost zero again.

(Embodiment) FIG. 1 shows an embodiment in which the present invention is applied to a gas flow meter.

4 is a valve chamber, and a diaphragm 6 provided across the valve chamber 4 divides the valve chamber 4 into an upstream valve chamber 4a and a downstream valve chamber 4b.

The tip of the upstream main channel 2a is guided to the upstream valve chamber 4a,
The tip of the downstream main flow path 2b is guided to the downstream valve chamber 4b. The tips of both main channels 2a and 2b are close to the diaphragm 6 so that when high pressure is suddenly applied to the upstream main channel 2a, the diaphragm 6 is displaced and can close the end of the downstream main channel 2b. , the tips of both main channels 2a and 2b face each other with the diaphragm 6 in between. A small hole is formed in the side wall of the main flow path 2b (area A in FIG. 1) in the downstream valve chamber 4b as a flow path through which gas passes with resistance.

At least on the downstream side of the area where the tips of one of the two main channels 2a and 2b of the diaphragm 6 face each other, so as to maintain airtightness when the diaphragm 6 is displaced and closes the tip of the downstream main channel 2b. A rubber sheet 8 is attached. Further, the diaphragm 6 is provided with an opening 10 that allows gas to pass therethrough with almost no resistance to a region other than the region where the tips of both main channels 2a and 2b face each other.

On the downstream side of this flow path valve, a differential pressure sensor 12 functioning as a flow meter is connected in parallel to the downstream main flow path 2b via a capillary tube 14.16.

Next, the operation of this embodiment will be explained.

When gas is being sent without sudden high pressure being applied from the upstream side, the diaphragm 6 has a small gap from both the tip of the upstream main channel 2a and the tip of the downstream main channel 2b, as shown in Fig. 1. It is in a remote state. At this time,
The gas that has flowed through the upstream main channel 2a flows through the upstream main channel 2a.
It enters the upstream valve chamber 4a from the tip of the diaphragm 6, enters the downstream valve chamber 4b through the opening 10 of the diaphragm 6, and flows into the downstream main channel 2b from the tip of the downstream main channel 2b.

The flow path resistance is approximately O.

When high pressure is suddenly applied from the upstream side, the diaphragm 6 receives force from the gas and is displaced as shown in FIG. Close the tip of 2b. This prevents sudden high pressure from being transmitted to the downstream side, and prevents sudden high pressure from being applied to the differential pressure sensor 12. While high pressure is applied from the upstream side, the tip of the downstream main channel 2b remains closed due to the pressure difference between the upstream and downstream sides of the diaphragm 6. However, the gas flowing through the upstream main flow path 2a enters the upstream valve chamber 4a from the tip of the upstream main flow path 2a, passes through the opening 10 of the diaphragm 6, enters the downstream valve chamber 4b, and enters the downstream main flow path. Since it gradually flows out into the downstream main channel 2b through the small holes in the side wall of the diaphragm 6, the pressure difference between the upstream and downstream sides of the diaphragm 6 becomes small after a certain amount of time.

Eventually, as shown in FIG. 3, the diaphragm 6 separates from the tip of the downstream main channel 2b, and the resistance returns to almost O state again.

In the embodiment, a case where gas is used is shown as an example, but the fluid to be flowed may be a liquid.

Moreover, although the embodiment shows an example in which a flow meter is configured by providing a differential pressure sensor on the downstream side of a flow path valve, the application is not limited to this. For example, it can be used as an operating valve when it is desired to prevent fluid from flowing out when there is no resistance or only small resistance on the downstream side.

(Effects of the Invention) The present invention does not act as a resistance during normal operation, but when high pressure suddenly acts, it closes the main flow path and acts to prevent sudden high pressure from being transmitted to the downstream side.

For example, when a flow meter is constructed by arranging a sensor on the downstream side, the failure pressure of the sensor can be set to a large value, and a flow meter with a wide allowable pressure range can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment in which the present invention is applied to a flow meter, and FIGS. 2 and 3 are cross-sectional views of a passage valve portion showing the operation of the same embodiment. 2a...Upstream main flow path, 2b...Downstream main flow path, 4...Valve chamber, 4a...Upstream valve chamber, 4b... ...Downstream valve chamber, 6...Diaphragm, 1o...Opening, 12...
・Differential pressure sensor, 14.16・Old...Capillary tube, A...
...A region where small holes are made. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] (1) The valve chamber is divided into an upstream side and a downstream side by a diaphragm, and the tips of the main flow channels are guided into both divided valve chambers, and the tips of both main flow channels are exposed to sudden high pressure in the upstream main flow channel. The diaphragm approaches the diaphragm so that it can close the tip of the downstream main flow channel when the flow is applied, and faces the diaphragm with the diaphragm in between. A flow path valve that is provided with an opening that allows fluid to pass therethrough with almost no resistance, and in which a main flow path in the downstream valve chamber has a side wall formed with a flow path that allows fluid to pass therethrough with resistance.