Diaphragm-type valve

Details Diaphragm-type valve Diaphragm-type valve

2001-03-16

2003-04-29

Lee, Kevin (Department: 3754)

Valves and valve actuation

Hermetic flexible wall seal for actuator

Diaphragm

C251S276000

Reexamination Certificate

active

06554251

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a diaphragm-type valve which is connected to a gas storing cylinder, a piping or the like for gas of ultra-high purity to be used during the production step of semi-conductors or the like.
2. Explanation of Related Art
The gas of ultra-high purity to be used during the production step of semi-conductors needs such a high purity as not allowing the contamination of a little impurity and besides has a corrosive action and a flammability. As such, it has so particular a characteristic that it requires a minute attention when being handled.
There is a conventional example of the diaphragm-type valve used for the gas which is employed when producing semi-conductors or the like, disclosed in Japanese Patent Public Disclosure No. 62-270872.
The conventional diaphragm-type valve comprises a housing within which an inlet bore communicates with an outlet bore via an inlet passage, a shut off valve chamber and an outlet passage in the mentioned order. The inlet passage opens to the shut off valve chamber and has a shut off valve seat formed on a periphery of its open end. The housing is provided with a shut off valve attaching bore, within which the shut off valve chamber is formed. A thrust screw member, an intermediate transmission means and a closure member are attached into the shut off valve attaching bore in the mentioned order from an exterior. The shut off valve chamber accommodates the closure member. A diaphragm is arranged between the closure member and the intermediate transmission means. The diaphragm hermetically seals the shut off valve chamber. Further, the shut off valve chamber accommodates a valve opening spring, which resiliently pushes the closure member in a direction away from the shut off valve seat, namely in a valve-opening direction.
The conventional technique accommodates the valve opening spring within the shut off valve chamber. Therefore, the valve opening spring contacts with fluid which flows through the shut off valve chamber. Besides, the shut off valve chamber cannot be downsized because it has to secure a space for accommodating the valve opening spring, which results in contacting with the fluid in a large area. This entails a problem of being unable to easily reduce the contamination into the fluid of impurities generating from contact surfaces between the fluid and either of the shut off valve chamber and the valve opening spring.
Moreover, if the valve is used to result in wearing off and deteriorating the closure member and the other members, it has to be exchanged. On the other hand, a housing of a valve is generally formed from stainless material or the like which has an excellent anti-corrosiveness. Accordingly, it is expensive and in many cases wears off and deteriorates more seldom than the other parts. Then, when exchanging the valve, it is desired to reuse the expensive housing. However, the closure member, the diaphragm and the intermediate transmission means are made of separate members, respectively and therefore have to be removed from the housing independently. Further, when incorporating new parts, they must be assembled one by one to result in making the exchanging work of parts troublesome.
SUMMARY OF THE INVENTION
The present invention has an object to reduce contact area with fluid which flows through an interior area of the valve and to facilitate the exchanging work of the closure member and the like parts.
In order to accomplish the above-mentioned object, the present invention has constructed a diaphragm-type valve in the following manner, for example, as seen from
FIGS. 1 and 2
showing an embodiment of the present invention.
The present invention comprises a housing
4
within which there are provided an inlet bore
6
, an inlet passage
8
, an outlet passage
10
, an outlet bore
11
and a shut off valve attaching bore
16
. The shut off valve attaching bore
16
has an intermediate transmission means accommodating space
25
, a shut off valve chamber
9
and a shut off valve seat
20
formed in the mentioned order from an exterior of the housing
4
to an interior thereof. A thrust screw member
17
, an intermediate transmission means
18
and a closure member
19
are attached into the attaching bore
16
in the mentioned order from the exterior. The shut off valve chamber
9
communicates with the inlet bore
6
through the shut off valve seat
20
and the inlet passage
8
as well as with the outlet bore
11
through the outlet passage
10
. The shut off valve chamber
9
accommodates at least part of the closure member
19
. Arranged between the intermediate transmission means
18
and the closure member
19
is a diaphragm
21
, which partitions the shut off valve attaching bore
16
into the intermediate transmission means accommodating space
25
and the shut off valve chamber
9
, and hermetically seals the shut off valve chamber
9
. Disposed in the accommodating space
25
is a valve opening spring
29
, which resiliently urges the intermediate transmission means
18
in a direction away from the shut off valve seat
20
.
The present invention functions as follows.
When a handle or the like rotating portion connected to the thrust screw member rotates the thrust screw member in a tightening direction, the thrust screw member spirally advances to produce a thrust. The intermediate transmission means which has received the thrust pushes the closure member through the diaphragm against a resilient pushing force of the valve opening spring. As a result, the closure member moves toward the shut off valve seat and comes into contact with the shut off valve seat to close the valve.
On the other hand, when the rotating portion is rotated in a loosening direction, the thrust screw member retreats to remove the thrust added to the intermediate transmission means. As a result, the intermediate transmission means is resiliently pushed in a direction away from the shut off valve seat by the resilient pushing force of the valve opening spring and the closure member fixed to the intermediate transmission means separates from the shut off valve seat to open the valve.
If the valve is used to result in wearing off the closure member and the other members or the like, it has to be exchanged. In the case where the housing is reused when making this exchange, a cap bolt and the like which fixes the thrust screw member is removed to take the respective parts out of the shut off valve attaching bore. At this time, the intermediate transmission means, the diaphragm and the closure member are mutually fixed. Therefore, they are easily handled as one unit. As for the housing from which the respective parts are removed, confirmation is made to see the housing does not suffer from a large wear or the like. And after having removed a likelihood of generating impurities, by washing and the like according to the need, new parts are incorporated into the shut off valve attaching bore. Also at this time, new closure member, diaphragm and intermediate transmission means are assembled into one set of unit. Accordingly, the respective parts are easily incorporated into the shut off valve attaching bore.
The present invention is constructed and functions as mentioned above and therefore produces the following advantages.
(1) The valve opening spring is arranged in the intermediate transmission means accommodating space and the shut off valve chamber accommodates only the closure member. This removes a probability that fluid which flows through the interior area of the shut off valve chamber contacts with the valve opening spring. Besides, there is no necessity of providing a space which accommodates the valve opening spring within the shut off valve chamber. Therefore, the shut off valve chamber can be formed into a small space, which results in the possibility of reducing a contact area with the fluid which flows through its interior area. This can decrease the contamination of impurities which generate from the valve, into gas of ultra-high purity.
(2) Since

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