Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
2000-02-02
2001-09-18
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
Reexamination Certificate
active
06289925
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a regulator for adjusting the pressure of pressurized fluid such as compressed air.
BACKGROUND ART
A regulator of this kind introduces pressurized fluid from an inlet port and regulates the pressure thereof to a set point to discharge the fluid from an outlet port. One example thereof is disclosed in U.S. Pat. No. 5,458,001. The regulator comprises a valve seat disposed in a fluid flow path interconnecting the inlet port and the outlet port, a diaphragm movably disposed in the outlet side of the valve seat, a poppet valve connected to the diaphragm for opening and shutting the valve seat from the inlet side by movement of the diaphragm, and a pressure-adjusting spring for urging the diaphragm in the direction that the poppet valve opens the valve seat. The poppet valve opens and shuts the valve seat by an amount of corresponding opening to the acting force difference between the outlet side fluid pressure mutually inversely applied to the diaphragm and the pressure regulating spring force, so that the fluid pressure in the inlet side is reduced to be regulated at a set point.
Since the diaphragm is prone to move not only in the axial direction but also in the direction that the axial line becomes inclined, such regulator has a weakpoint in that the poppet valve connected to the diaphragm is likely to contact and separate from the valve seat in an inclined state thereof so that the opening and shutting operation of the poppet valve is unstable, resulting in the poor accuracy of pressure adjusting. The regulator also has another defect in that localized wear is prone to be produced by contacting and separating from the valve seat of the poppet valve in an inclined state thereof so as to reduce the durability of the regulator.
DISCLOSURE OF INVENTION
A principal technical problem to be solved of the present invention is to stabilize the opening and shutting operations of a poppet valve by preventing a diaphragm and the poppet valve from being inclined to thereby increase the pressure adjusting accuracy of a regulator.
Another technical problem to be solved of the present invention is to eliminate localized wear due to the deviated contact in the regulator so as to increase its durability.
In order to solve the above-mentioned problems, a regulator according to the present invention comprises: a valve seat disposed in a fluid flow path interconnecting the inlet port and the outlet port; a diaphragm disposed in the outlet side of the valve seat; a piston connected to the diaphragm moving along with the diaphragm; a poppet valve attached to the piston for opening and shutting a valve seat hole of the valve sheet from the inlet side; a sleeve slidably containing the piston and guiding the piston so that the axial line thereof does not incline when the piston moves; and a pressure-setting mechanism for setting the outlet pressure.
In the regulator formed as described above, when the piston is pushed down by the pressure-adjusting spring of pressure-setting mechanism to displace the diaphragm toward the valve seat, the poppet valve separates from the valve sheet to open the valve seat hole, so that the pressurized fluid in the inlet side (inlet port) flows into the outlet side (outlet port) via the valve seat hole.
The fluid pressure in the outlet side is exerted on the diaphragm to produce an operating force in the direction opposite to that by the pressure-adjusting spring which in turn causes the poppet valve to open the valve sheet
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an amount of corresponding opening to the acting force difference therebetween. While the fluid pressure in the outlet side is smaller than the setting-pressure, the poppet valve opens to introduce the pressurized fluid from the inlet toward the outlet. When the fluid pressure in the outlet side increases to reduce the pressure difference with the setting-pressure, the diaphragm moves away from the valve seat, so that the amount of opening of the poppet valve decreases. When the pressure difference is reduced to zero to keep the operating forces in equilibrium, the poppet valve closes to set the fluid pressure in the outlet side.
Since the diaphragm is guided by the sleeve via the piston, the displacement thereof corresponding to the outlet side pressure is securely and steadily performed only in the axial direction without inclination of the axial line or lateral runouts. Accordingly, the poppet valve connected to the diaphragm does not also incline or waggle laterally and is securely displaced only in the axial direction to open and shut the valve seat, thereby resulting in improved accuracy in pressure regulation by the stable and precise opening and shutting operations. Furthermore, since localized wear due to deviated contact cannot be produced, durability can be also increased.
According to a preferred specific embodiment of the present invention, the piston and the sleeve may comprise front-end portions having smaller diameters and rear-end portions having larger diameters, respectively, the piston and the sleeve being slidably in contact with each other in the front-end portions and the rear-end portions, and wherein a step portion may be formed in the inner surface of the sleeve as a stopper so as to abut the rear-end portion of the piston when the piston advances fully.
Therefore, not only can the inclination of the diaphragm be more securely prevented but also when the fluid pressure of the outlet side is suddenly dropped or when the outlet side becomes under zero pressure or vacuum, but also problems in the diaphragm or the piston impacting the valve seat or other members to be damaged or to produce dust can be avoided with reliability.
According to another preferred specific embodiment of the present invention, a regulator may further comprise: a body; and a cover detachably connected to the body, wherein in the body is disposed the inlet port and the outlet port and in the cover is disposed the sleeve, the piston, the diaphragm, and the pressure-setting mechanism. Between the body and the cover, an outer peripheral portion of the diaphragm is hermetically clamped and a plate for fitting the valve seat is provided, and the valve seat is disposed in a clamped state between the plate and the body.
When the outer peripheral portion of the diaphragm is clamped between annular clamping portions formed in the body and the cover from both sides, in order to improve hermeticity, it is desirable that any one surface of those of the clamping portions be planar while a bead be formed on the other.
According to another embodiment of the present invention, the body and the cover may be connected by the clamping ring having a retaining portion retaining at an exterior flange in the outer periphery of the cover and a female thread portion screwed with a male thread portion on the outer periphery of the body, wherein sliding-guiding means are interposed between the retaining portion and the flange of the cover.
According to still another embodiment of the present invention, the pressure-setting mechanism includes a return spring for urging the piston in the direction that the poppet valve closes and the return spring may include at least one of a coil spring and a leaf spring.
When the return spring is a coil spring, the coil spring is disposed within the sleeve between the inner surface of the sleeve and the outer peripheral surface of the piston.
When the return spring is a leaf spring, the leaf spring is formed as an annular ring and the piston is retained at the central portion of the spring while the outer peripheral portion thereof is retained at the body or the cover. Thereby, the leaf spring is closely fitted with in a position of the rear of the diaphragm not obstructing normal deflection of the diaphragm.
According to the present invention, it is preferable that the poppet valve have a conical sealing surface and comprise a flow-restricting portion close to the center of the conical surface in a portion fitting into the valve sheet hole, the conical surface in the flow-restricting portion havin
Katsuta Hiroyuki
Miyazoe Shinji
Tajima Masamichi
Hepperle Stephen M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
SMC Corporation
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