JP3130490B2 - Gas cylinder-valve connection fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas cylinder-valve connection joint used for connecting a gas cylinder-valve to a gas pipe in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a large number of special gases are used. Generally, as shown in FIG. Is mounted, and a gas cylinder-valve is connected to the gas outlet 3 and introduced into a predetermined pipe.

Most of these special gases are flammable, toxic,
Since it is a hazardous gas such as corrosive gas, the connection with the gas cylinder-valve, which is always attached and detached when replacing the gas cylinder, is the place where the highest safety is required.

As such a gas cylinder-valve,
As shown in FIG. 2, the connection joint conventionally used includes a female nut 4 threadedly connected to the outer peripheral thread portion of the gas outlet 3 of the gas cylinder, and a gland 5 fitted to the female nut 4. The distal end of the gland 5 is configured to be connected to the gas outlet 3 of the gas cylinder via the gasket 6 by screwing the female nut 4 together.

Since the gland 5 serves to introduce the gas in the gas cylinder into the pipe, the other end of the gland 5 is fixed to the pipe 7 of the gas pipe by welding or the like.

[0006]

Since the conventional gasket 6 is made of a synthetic resin such as Teflon or the like, the female nut 4 is excessively tightened because there is a fear that gas may leak to the outside. Accidents causing deformation or breakage of No. 6 frequently occurred, rather causing gas leakage accidents.

Further, when tightening the female nut 4, a tool such as a wrench is used. However, as is apparent from the structure of the cylinder-valve shown in FIG. 1, the tool may hit the valve handle 12 when tightening. When the handle 12 is rotated in the opening direction, a large amount of gas leaks, and there is a risk of a serious accident.

In the conventional connection joint, the dimensional difference between the outer diameter of the hole provided in the female nut 4 through which the gland 5 penetrates and the outer diameter of the penetrating gland 5 is large.
This is because, when the dimensional difference is small, a slight bending load is applied to the gland 5 at the time of screwing at the initial tightening, this load is transmitted to the female nut 4, and the screwing at the initial tightening and the proper angle This is because tightening becomes difficult.

[0009] Furthermore, in a semiconductor manufacturing plant, a method of leak test of a connection joint detachable portion which is generally performed at present is to pressurize helium gas from the inside of the pipe after tightening is completed and helium gas leaking from the detachable portion to the outside. A suction method for measuring the molecular weight of gas using a suction type helium leak detector, and a helium leak detector connected to an airtight test port provided in advance, and a connection pump connected by a vacuum pump built in the helium leak detector. It has been performed by evacuating the inside and blowing helium gas to the attaching / detaching portion.

In any of the above methods, the detachable portion of the connection joint after tightening is covered with the female nut, so that if a small amount of leakage occurs, it is extremely difficult to find out.

An object of the present invention is to provide a connecting joint which can minimize the amount of deformation of a synthetic resin gasket even when a female nut is excessively tightened. I do.

The invention described in claim 2 is the first invention.
In addition to the object of the invention described in (1), it is another object of the present invention to provide a connection joint that prevents co-rotation at the time of tightening without directly contacting the bottom of the female nut and the gland.

[0013] The invention described in claim 3 is the first invention.
In addition to the object of the invention described in (1), an object of the present invention is to provide a connection joint capable of screwing at the initial stage of tightening and tightening at an appropriate angle without being affected by bending load.

The invention described in claim 4 is the first invention.
Another object of the present invention is to provide a connection joint that makes it easy to find a leak even in a small amount in leak tests of both a suction method and a vacuum method.

The invention described in claim 5 is the first invention.
Another object of the present invention is to provide a connection joint that eliminates the risk of a large amount of gas leaking when a tool hits a valve handle when tightening the connection joint.

[0016]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 of the present invention provides a gas cylinder having a threaded portion on the inner circumference of a female nut into which a gland is removably fitted. A gas cylinder-to-valve connection joint that presses a synthetic resin gasket interposed between the gland and the gas cylinder-to-valve outlet while screwing a threaded portion around the valve outlet to connect to the gas cylinder-to-valve outlet. A ring-shaped concave groove on the outer periphery of the gasket.
And a metal ring for preventing excessive tightening is attached to the concave groove .

According to a second aspect of the present invention, a thrust bearing is interposed between the gland and the bottom of the female nut in the configuration of the first aspect, and the gland of the bottom of the female nut is fitted. An opening is formed by connecting an opening having a diameter substantially the same as the outer diameter of the gland to an opening tapered from the bottom surface toward the outlet, and a ring-shaped recess is formed in the ground facing the tapered opening slope. Forming a groove,
A wire for positioning a thrust bearing in the concave groove;
It is characterized by adding a configuration in which a ring is fitted.

According to a third aspect of the present invention, in the configuration of the first aspect of the present invention, the opening of the female nut in which the gland is fitted and the diameter of the gland are sufficiently free in the initial stage of tightening. It is characterized by adding a configuration in which a step is formed in the ground so that the degree is maintained, and when the tightening is completed, there is almost no degree of freedom.

According to a fourth aspect of the present invention, there is provided a seal which is in contact with the structure of the first aspect of the present invention via the gasket.
The female nut facing the lubricating surface has a configuration in which a plurality of through holes for a gas leakage test are formed.

According to a fifth aspect of the present invention, in the configuration of the first aspect of the present invention, the outer peripheral polygonal female nut is formed to be longer than in the prior art, and the outer periphery of the female nut on the gas cylinder side is formed with a spanner or the like. It is characterized in that a configuration in which a corner is formed so as not to be tightened by a tool is added.

[0021]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 3, a ring-shaped concave groove is formed on the outer periphery of a synthetic resin gasket 6 such as Teflon, and a metal ring 7 having a thickness of about half of the gasket is fitted in the concave groove. Here is an example.

By fitting the metal ring 7 in this manner, even if excessive tightening is performed, the amount of deformation of the gasket 6 can be suppressed to a minimum, and the thickness of the metal ring 7 can be reduced to a value less than the thickness. Since it cannot be tightened, it also has a stopper function to prevent gasket breakage.

In the above embodiment, the metal ring 7 is pressed into and held in the ring-shaped concave groove formed on the outer periphery of the gasket 6. This doesn't have to be like this,
When formed in this manner, the metal ring 7 is
Proper positioning can be performed so as not to move or fall off from the proper position.

In the conventional connection joint, when the female nut 4 is tightened, the friction around the contact portion between the female nut 4 and the gland 5 causes the gland 5 to co-rotate.
As a result, the contact surface between the gland 5 and the gasket 6 is rubbed, and the airtightness is reduced, or a torsion stress remains in the pipe 7 connected to the gland 5, and when this is continuously used, the female nut 4 or The other screw connections became loose, which caused gas leakage.

As shown in FIG. 3, a thrust bearing 8 is interposed at the bottom of the gland 5 and the female nut 4 of the connection joint of the present invention. Therefore, since the female nut 4 and the gland 5 do not directly contact with each other, it is possible to prevent co-rotation during tightening.

As shown in FIG. 3, the opening of the female nut 4 into which the gland 5 is fitted is formed by connecting an opening having a diameter substantially equal to the outer diameter of the gland 5 to an opening tapered from the bottom surface toward the outlet. It is formed by providing.

A concave groove is formed in the ground 5 facing the slope of the opening tapered from the bottom toward the outlet.
A wire ring 9 for positioning the thrust bearing 8 is fitted and mounted in the groove.

The wire ring 9 is, as shown in FIG.
Since it is formed in a ring shape with one end opened from an elastic metal wire, it is extremely easy to mount and remove,
Workability such as individual cleaning, inspection, and assembly of these parts can be dramatically improved.

The diameter of the gland 5 fitted into the opening of the female nut 4 has a sufficient degree of freedom in the initial stage of tightening.
At the end of the tightening, a step is formed in the ground 5 so that there is little freedom.

By forming the diameter of the gland 5 in two steps as described above, screwing at the initial stage of tightening and tightening at an appropriate angle can be performed. The difference in outer diameter between the opening of the female nut 4 and the gland 5 at the end of the tightening is 0.
It is good to form it so that it may be about 1 mm to 0.5 mm.

Gas cylinder-valve outlet 3 and gland 5
However, a plurality of through holes 10 for a gas leakage test are formed in the female nut 4 facing the vicinity of the seal surface contacting with a gasket. The through-holes 10 are preferably formed at two or three locations in order to facilitate a leakage test of the female nut 4.

It is preferable that the through-hole 10 is located at a position close to the seal surface or the seal surface, since a leak test can be performed with high sensitivity. Thus, the through hole 1
By forming 0, a leak test can be performed very easily.

The female nut 4 is formed longer than before,
The outer periphery of the female nut 4 on the gas cylinder side, which is connected to the hexagonal portion of the outer periphery, is formed in the circular portion 11. Circular part 1
1 is not necessarily a circle as long as it has a shape with a corner portion dropped so that it cannot be tightened with a tool such as a spanner.

By forming in this manner, there is no danger of a large amount of gas leaking when a tool such as a spanner hits the valve handle.

[0035]

As described above, according to the first aspect of the present invention, even when the female nut is excessively tightened, the amount of deformation of the synthetic resin gasket can be minimized, and It is possible to eliminate a gas leak accident caused by deformation or breakage of the gas.

According to the second aspect of the invention, in addition to the effect of the first aspect, since the female nut and the gland are not brought into direct contact with each other, co-rotation during tightening can be prevented.
It is possible to eliminate a gas leakage accident caused by applying a torsional stress to the pipe.

According to the third aspect of the present invention, in addition to the effect of the first aspect, screwing at the initial stage of tightening and tightening at an appropriate angle can be performed without being affected by bending load, and airtightness can be easily achieved. Nature can be maintained.

According to the fourth aspect of the present invention, in addition to the effect of the first aspect, it is very easy to find the leakage even in a small amount in any of the suction test and the vacuum test.

According to the fifth aspect of the present invention, in addition to the effect of the first aspect, when tightening the connection joint, the risk that a large amount of gas leaks when the tool hits the valve handle.

[0040]

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a conventional gas cylinder.

FIG. 2 is a half sectional view showing a conventional gas cylinder-valve connection joint.

FIG. 3 is a half sectional view showing a gas cylinder-valve connection joint of the present invention.

FIG. 4 is a top view showing a wire ring used in the present invention.

[Explanation of symbols]

 Reference Signs List 4 female nut 5 gland 6 gasket 7 metal ring 8 thrust bearing 9 wire ring 10 through hole for gas leak test 11 circular part around female nut

Continuation of the front page (56) References JP-A-7-243563 (JP, A) JP-A-63-178686 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16L 19 / 08 F16J 15/06

Claims (5)

(57) [Claims] 1. A screw thread on the inner circumference of a female nut for detachably fitting a gland and a screw thread on the outer circumference of a gas cylinder-valve outlet are interposed between the gland and the gas cylinder-valve outlet. A ring-shaped concave groove is formed on the outer periphery of the gasket at the gas cylinder-valve connection joint which presses the synthetic resin gasket to connect to the gas cylinder-valve outlet, thereby preventing excessive tightening of the concave groove. A gas cylinder-valve connection joint comprising a metal ring mounted thereon. 2. A thrust bearing is interposed between the gland and the bottom of the female nut, and an opening for fitting the gland at the bottom of the female nut is formed in an opening tapered from the bottom to the outlet. A wire for forming a ring-shaped groove in the ground opposed to the tapered opening slope, and forming a thrust bearing in the groove. The connection joint according to claim 1 , wherein a ring is fitted. 3. The opening of the female nut in which the gland fits, and the diameter of the gland are maintained at a sufficient degree of freedom at the beginning of tightening, and at the end of tightening, the degree of freedom is reduced. connection fitting according to claim 1 or 2 by forming a stepped portion. 4. A contact via the gasket sheet - the Mesunatto near the site or opposing part facing the Le surfaces, according to claim 1 to 3 obtained by forming a plurality of through holes for the leak testing of gas The connection joint according to any one of the above. 5. The method according to claim 1, wherein the outer peripheral polygonal female nut is formed longer than before, and the outer periphery of the female nut on the gas cylinder side is formed with a corner portion dropped so as not to be tightened with a tool such as a spanner. Any one of items 1-4
Connection joint according to item.