JPH0425682A - Selector valve for gaschromatograph - Google Patents

Abstract

PURPOSE:To reduce the extent of fluid resistance as well as to improve the mounting attitude of a plunger and its vibration proof by forming a center plate with a nonmagnetic material and two plungers, being opposed to each other in holding the former in between, with a magnet, then setting the counter polarity down to homopolarity. CONSTITUTION:A center plate 2 is formed with a nonmagnetic material such as stainless steel or the like, while plungers D1-Dn, E1-En are formed with a magnet each, and each polarity of these plungers D1-Dn and E1-En is made so as to make the counter polarity come to the same one, and these plungers are inserted into each insert hole of both upper and lower cylinder plates 12, 13 free of slide motion. With this constitution, the OFF-side plunger is forcibly separated from a diaphragm by dint of repulsive force and pressable to the OFF-side piston, while fluid resistance is reducible as well. Accordingly, even in the case where gas pressure is small, passage transfer is smooth and accurate and, what is more, a mounting attitude of each plunger is good enough, thus a fluid variation is relievable or preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a gas chromatograph switching valve suitable for use in high-speed process measurement.

[Conventional technology] A process gas chromatograph holds a sample gas, passes this sample gas through multiple columns using a carrier gas, separates the gas components, and sends the separated gas components to the detection section. The system automatically repeats a series of operations in accordance with a sequence, including measuring the concentration of chlorine and flushing the pipes and columns with carrier gas to clean them for the next sampling. In order to improve response speed, it is necessary to send a small amount of sample gas at high speed, so the diameter of the flow path such as the metering tube or column must be extremely small, the switching valve must be small, and the internal capacity must be small. desired.

Therefore, a pneumatically driven diaphragm valve is generally used as a switching valve for this type of process gas chromatograph, and an example of this is shown in FIG. A diaphragm 3 is provided on the front and back surfaces of the center plate 2, which has a plurality of fluid passages Al to An formed concentrically through the center plate 2.
．． 4 in close proximity and multiple 1 ranjiya D! ~Dn
, E1-En are arranged corresponding to each of the fluid passages A1-An, and the diaphragm 3.4 is elastically deformed by the carrier gas or sample gas supplied to the fluid passages Al-An, and the plungers D1-Dn, E.

By actuating ~En by air pressure P applied alternately via pistons 5.6, the driftwood passages A, ~
The upper route and the lower route of An are alternately switched.

In case 2, in FIG. 2, the air pressure P is supplied to the air pressure receiving chamber 7, and the upper piston 5
! ~ By pressing down Dn all at once, the fluid passage A1
While closing the upper route of ~An, supply air pressure P to the air pressure receiving chamber 8 to lower the lower piston 6, release the pressed state of the lower plungers E1~En, and release the sample gas (or carrier gas). pressure P. Due to fluid passage A
1 to An are shown with their lower routes open.

In other words, this type of switching valve 1 adopts a method in which the diaphragm 4 on the plunger OFF side is elastically deformed by the gas pressure Po to switch between the lower route and the lower route of the fluid passages A, ~An, and to flow the fluid. It is.

In addition, 10 is a top cylinder, 11 is a bottom cylinder,
12 is an upper cylinder plate, 13 is a lower cylinder plate, and 14 is an O-ring.

"Problem to be solved by the invention" By the way, in the conventional switching valve of this type, the gas pressure P
. If the diaphragm 3.4 is small, the diaphragm 3.4 cannot be pushed up sufficiently, resulting in poor gas flow. Therefore, a device with low fluid resistance has been required. However, simply by piston 5.6, one lunge DI~D,,El~E,
of! There was a problem in that the mounting position of the plunger was not constant when the plunger was turned off, and it was easily moved due to vibration. In particular, regarding the mounting position, for example, when the switching valve is used in an upright position, a conventional problem arises in that the upper plunger narrows the fluid passage due to its own weight. Regarding vibration resistance,
When installed on site, it is impossible to reliably prevent the plunger from wobbling due to piping vibration with the plan.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a simple structure in which the plunger is forcibly separated from the diaphragm when the first plunger is OFF, and to reduce fluid resistance. It is an object of the present invention to provide a switching valve for a gas chromatograph, which has a reduced plunger mounting position and vibration resistance.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention elastically deforms a diaphragm provided between the center plate by gas pressure, thereby blocking the fluid passage formed in the center plate, and In the switching valve for a gas chromatograph, which closes the fluid passage by pressing the diaphragm, the center plate is formed of a non-magnetic material, and the first rungs facing each other with the center plate sandwiched therebetween are formed of magnets. , whose opposing polarities are the same polarity.

[Function] In the present invention, the plungers arranged opposite to each other with the center plate in between are magnets with the same opposing polarity, and one plunger on the OF and F side is moved by repulsive force to FFII.
Separate from the J diaphragm.

[Example] The present invention will be described in detail below based on two examples shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of a gas chromatograph switching valve according to the present invention. Components in the figure that are the same as those in FIG. 2 are designated by the same reference numerals, and their explanations will be omitted. In this embodiment, the center plate 2 is made of a non-magnetic material such as stainless steel, and one runr D, ~D, ,E
, , ~E are made of magnets, the piston 5.6 is made of a magnetic material such as iron, and the plungers D1 to Dn and the plunger E are opposed to each other with the center plate 2 in between.

~The polarity of En is changed so that the opposite polarity is the same, for example, N
This device is characterized in that these 1 plunger D1"Dn and plungers El to En are slidably inserted into the insertion holes of the upper and lower cylinder plates 12.13, respectively, with their poles facing each other, and other configurations is the same as the conventional structure.

In a switching valve for a gas chromatograph having such a configuration, plungers D1 to Dn and plungers El to each made of a magnet face each other with the center plate 2 in between.
Since the opposing polarities of En are the same, they receive a force in the direction of separating them from each other due to repulsive force. Also, piston 5.
Since 6 is a magnetic material, the plungers Dl-Dn and plungers El-En are each attracted to the piston 5.6 by magnetic force.

Now, when the lower plungers EI to En in the figure are OFF, the plungers E1 to En are released from the pressure of the piston 6, but they move toward the piston 6 side due to the action of the repulsive force L and the magnetic force, and move away from the diaphragm 4. Separate. Therefore, the diaphragm 4 can be easily deformed, and the fluid passages A, -A
It is possible to reduce the fluid resistance of , to operate well even when the gas pressure Po is low, and to reliably prevent the flow of the carrier gas or sample gas from stopping or decreasing.

In addition, since the plungers D, ~Dn, and El~En are each attracted to the piston 5.6 by repulsive force and magnetic force, they maintain stable postures and are free from external vibrations and diaphragm 3 during switching.
．． There is less vibration due to deformation of the valve 4, etc., and flow rate fluctuations can be reduced.

In addition, although the above embodiment describes the case where the piston 5.6 is formed of a magnetic material, the present invention is not limited to this. If the center plate 2 is thin, it may be formed of a non-magnetic material.

[Effects of the Invention] As explained above, in the switching valve for gas chromatograph according to the present invention, the center plate is made of a non-magnetic material, and the first langeers arranged facing each other across the center plate are magnets, and the opposing polarities are made to be the same polarity. Therefore, it turns off due to repulsive force.
Force the side plunger away from the diaphragm to
It can be pressed against the FFIIJ piston, reducing fluid resistance. Therefore, even when the gas pressure is low, the flow path switching is smooth and reliable, the gas flow does not stop or drop, the plunger is mounted in a good posture, there is little vibration due to external vibration, and fluid fluctuations are prevented. The reliability and measurement accuracy of the switching valve can be improved. In addition, the structure is simple,
It can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a gas chromatograph switching valve according to the present invention, and FIG. 2 is a cross-sectional view showing a conventional example of a gas chromatograph switching valve. 2. Center plate, 3.4 Diaphragm, 5.6 Piston, 7.8 Air pressure receiving chamber, 10
...Top cylinder. 11...Bottom cylinder, 12...Upper cylinder plate, 13...Lower cylinder plate, D1 to Dn, E
, ~En...Plunger, A1~An...Fluid passage. Diagram

Claims (1)

[Scope of Claims] A fluid passage formed in the center plate is opened by elastically deforming a diaphragm provided between the center plate by gas pressure, and the fluid passage is closed by pressing the diaphragm with a plunger. In the gas chromatograph switching valve according to the present invention, the center plate is formed of a non-magnetic material, and the plungers facing each other with the center plate in between are formed of magnets, and their opposing polarities are the same. Switching valve for use.