Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
1999-03-23
2001-01-23
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
C137S505110, C137S505410, C137S505420, C137S544000
Reexamination Certificate
active
06176256
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas pressure-reducing valve and, more particularly, to a gas pressure-reducing valve in which a valve member to be seated on a valve seat having a valve hole opened at its central portion and leading to a pressure-reducing chamber between a body and a diaphragm is fixed on a valve stem connected to the central portion of the diaphragm and is disposed coaxially with the valve axis.
2. Related Art
Such a gas pressure-reducing valve has already been known in the prior art from Japanese Patent Application Laid-open Nos. 3-260483 and 8-334182 and the like.
In the gas pressure-reducing valve disclosed in the above Japanese Patent Application Laid-open No. 3-260483, a valve seat is formed on the inner end of an accommodation bore that is formed in a body for accommodating a valve member, and a cover member for sealing the outer end of the accommodation bore is mounted on the body. Not only the number of parts is large, but also a cover and the mentioned cover member have to be attached to both sides of the body, and hence the degree of freedom for arranging the gas pressure-reducing valve in the body is narrowed.
In the gas pressure-reducing valve disclosed in Japanese Patent Application Laid-open No. 8-334182, on the other hand, a valve body to be screwed in a mounting bore formed in a body is constructed to have a valve seat and to accommodate a valve member. This construction is also troubled like Japanese Patent Application Laid-open No. 3-260483 by the increased number of parts and the narrowed degree of freedom for arranging the gas pressure-reducing valve in the body.
SUMMARY OF THE INVENTION
The invention has been accomplished in view of the background thus far described and has an object to provide a gas pressure-reducing valve which is reduced in the number of parts and enhanced in the degree of freedom for arrangement in the body.
In order to achieve the above-specified object, according to a first feature of the invention, there is provided a gas pressure-reducing valve comprising a diaphragm clamped at a peripheral edge portion thereof between a body and cover fastened to the body for constructing a valve housing together with the body, the diaphragm is spring-urged toward a side which reduces the capacity of a pressure-reducing chamber formed between the diaphragm and the body, in which a valve member that can be seated on a valve seat having at a central portion thereof with a opened valve hole leading to the pressure-reducing chamber is fixed on a valve stem connected to the central portion of the diaphragm and arranged coaxially with the valve hole, wherein a bottomed mounting bore arranged coaxially with the valve stem and opened toward the pressure-reducing chamber is provided in the body, wherein a cylindrical valve seat member forming a valve chamber between itself and a closed end of the mounting bore for accommodating the valve member and inserted into the mounting bore is fixed on the body, and wherein the valve seat facing the valve chamber is formed on an inner surface of an end portion of the valve seat member on the side of the pressure-reducing chamber.
With the above arrangement of the first feature, the valve seat member having the valve seat is inserted and fixed in the bottomed mounting bore which is formed in the body and opened toward the pressure-reducing chamber and the valve member is accommodated in the valve chamber formed between the valve seat member and the body. This arrangement makes it unnecessary for the members such as the cover member to be mounted and accordingly makes it possible to reduce the number of parts and to increase the degree of freedom for arranging the gas pressure-reducing valve in the body. Further, the valve seat is formed on the inner surface of the end portion of the valve seat member on the side of the pressure-reducing chamber so that the valve member can be arranged as close to the pressure-reducing chamber as possible thereby to make a contribution to the size reduction of the body.
In addition to the above first feature, according to a second feature of the invention, wherein one end portion of the valve stem is borne on the body so as to be movable in the axial direction thereof, a plurality of guide portions f or coming into sliding contact with the inner surface of the valve seat member at a plurality of circumferentially spaced portions are provided on the outer surf ace of the valve member made of a synthetic resin, and wherein a passage extending in the axial direction of the valve stem is formed between the guide portions and between the valve member and the valve seat member.
With the above arrangement of the second feature, the valve stem is borne axially movably by the body at its one-end portion and through the valve member and the valve seat member by the body at its portion in which the valve member is fixed. Even if the transverse load by the spring which urges the diaphragm toward the pressure-reducing chamber acts on the valve stem or if the diaphragm is misaligned when its peripheral edge portion is to be clamped between the body and the cover, the valve stem can be prevented from falling down to align the valve seat and the valve member accurately, so that the valve member can be reliably seated on the valve seat along its entire periphery. Moreover, the sliding resistance, which is caused when the respective guide portions provided on the valve member of a synthetic resin come into sliding contact with the inner face of the valve seat member, is generated against the vibration of the spring for urging the diaphragm toward the pressure-reducing chamber, so that the establishment of the self-excited vibration can be prevented to the minimum.
In addition to the above first feature, according to a third feature of the invention, an internal thread for fastening the valve seat member is formed in the inner surface of the mounting bore, and a plurality of projections for forming therebetween a plurality of grooves extending radially of the valve stem in a plane normal to the axis of the valve stem are protruded from an end surface of the valve seat member on the side of the pressure-reducing chamber.
With the above arrangement of the third feature, a tool can be applied to the groove between the respective projections to turn the valve seat members so that the valve seat member can be easily mounted on the body. Moreover, the deflection of the diaphragm in the direction for the valve member to be moved apart from the valve seat can be regulated by the respective projections, and the communication of the gas between the valve chamber and the pressure-reducing chamber is allowed through the respective grooves even with the diaphragm abutting against the respective projections.
In addition to the above first feature, according to a fourth feature of the invention, on one of the valve housing and a reciprocating member slidably fitted in the valve housing so as to reciprocate in the axial direction of the valve hole in accordance with deflections of the diaphragm, a plurality of ring members are mounted to come into elastically sliding contact with the other of the reciprocating member and the valve housings so that the ring members are spaced from each other in the axial direction of the reciprocating member, and a space defined between the ring members and between the reciprocating member and the valve housing is filled with grease.
With the above arrangement of the fourth feature, the ring members, as mounted on one of the reciprocating member and the valve housing, are brought into elastically sliding contact with the other of the reciprocating member and the valve housing so that the sliding resistance against the self-excited vibration by the coil spring can be achieved. Since the space between the individual ring members and between the reciprocating member and the valve housing is filled with grease, moreover, the outflow of the grease can be avoided to the least even after a long operation thereby to suppr
Arai Nobuo
Goto Hiroyuki
Ishikawa Kazuki
Iwasaki Hiroyuki
Nakajima Yoji
Arent Fox Kintner Plotkin & Kahn
Hepperle Stephen M.
Keihin Corporation
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