Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
2000-02-02
2001-09-11
Hepperle, Stephen (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
C251S362000
Reexamination Certificate
active
06286544
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 an amount corresponding to the opening of the acting force difference between the outlet side fluid pressure mutually inversely applied to the diaphragm and the pressure-adjusting spring force, so that the fluid pressure in the inlet side is reduced to be regulated at a set point.
In the above-mentioned regulator, the valve seat is attached to a body via a dish-shaped seat holder having a central hole being a fluid flow path and a recess portion around the central hole. That is: the seat holder in a state that the valve seat is fitted into the recess portion is placed on the body; a cap is attached on the body in that state; and the body and the cap are clamped together by a nut-type clamping ring, so that the outer peripheral portion of the seat holder is fixed between the body and the cap in a highly pressurized state while the valve seat is fitted between the seat holder and the body in a compressed state.
However, in the method of fitting the valve seat via the seat holder in a compressed state, the seat holder is prone to be deformed by a compressing reaction force of the valve seat because when the clamping ring is strongly clamped, the valve seat is also strongly compressed by the seat holder, so that when the deformation is excessive, hermeticity between the valve seat and the seat holder or the body is likely reduced.
Since between the body and the cap, not only the outer peripheral portion of the seat holder but also the outer peripheral portion of the diaphragm is simultaneously clamped in a hermetic state, it is necessary that thickness of the seat holder is controlled with a high degree of accuracy so that the clamping force to the diaphragm is not reduced by the interposition of the seat holder, requiring troublesome processing.
DISCLOSURE OF INVENTION
In a type of regulator attaching the valve seat via the seat holder, a principal technical problem to be solved of the present invention is to fit the valve seat in a state maintaining high hermeticity by eliminating excessive deformation due to a compressing reaction force. In the above-mentioned regulator, another technical problem to be solved of the present invention is to fix both the diaphragm and the seat holder in a clamping state simultaneously and securely between the body and the cap without reducing hermeticity of the diaphragm.
In order to solve the above-mentioned problems, a regulator according to the present invention comprises: a seat holder fitted within the pressure chamber by clamping the fitting portion in the outer periphery thereof between the body and the cap; and a valve seat fitted between the seat holder and the body in a compressed state, wherein a recessed groove is formed in the outer periphery of the valve seat for absorbing an excessive compressing force by the seat holder.
In the regulator formed as described above, when the clamping ring is fastened, a compressing force acted on the valve seat via the seat holder is absorbed by elastic deformation of the valve seat in the recessed groove, so that the seat holder cannot be excessively deformed by a compressed reaction force of the valve seat. Therefore, deterioration due to the excessive deformation of hermeticity between the valve seat and the seat holder or the body cannot be produced.
According to a preferred embodiment of the present invention, the seat holder may be clamped between the body and the cap via an elastic washer.
By providing such with the washer, when the clamping ring is fastened, a clamping force acted on the seat holder is also absorbed and relieved by elasticity of the washer, resulting in easier and secure mounting of the valve seat and, moreover, such is accomplished with a high degree of accuracy. Furthermore, both the seat holder and the diaphragm can be securely and simultaneously fixed in a clamped state without reducing hermeticity of the diaphragm.
According to another preferred embodiment of the present invention, a bead may be formed on the surface of the body abutting the valve seat for improving hermeticity with the valve seat.
According to still another preferred embodiment of the present invention, the poppet valve having a conical sealing surface may comprise a flow-restricting portion close to the center of the conical surface in a portion fitting into the valve seat hole, the conical surface in the flow-restricting portion having a steeply inclined generating line.
Thereby, when the poppet valve opens, the flow-restricting portion is gradually shifting out of the valve seat hole, so that the valve seat hole is prevented from being opened suddenly. When the poppet valve shuts, the valve seat hole is also prevented from being closed suddenly owing to fitting of the flow-restricting portion into the valve seat hole gradually, resulting in a reduction in variations in pressure in the outlet side.
In this case, besides the flow-restricting portion of the poppet valve, or instead of the flow-restricting portion of the poppet valve, a flow-restricting portion may be formed in a portion of the valve stem located in the outlet side of the valve seat for restricting the flow of pressurized fluid by narrowing the flow path when the poppet valve fully opens.
According to a preferred specific embodiment of the present invention, a piston may be attached to the rear surface of the diaphragm while a sleeve for guiding is attached inside the cap, the piston being slidably inserted into the sleeve.
In this configuration, the diaphragm is guided by the sleeve and the piston, the displacement thereof is securely and steadily performed in the axial direction without inclination or lateral runouts, so that the poppet valve does not also incline or waggle laterally, thereby resulting in improved accuracy in pressure regulation by the stable and precise opening and shutting operations. Furthermore, localized wear due to deviated contact cannot be produced.
According to another embodiment of the present invention, the return spring may include at least one of a first return spring formed of a coil spring and a second return spring formed of a leaf spring.
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Katsuta Hiroyuki
Miyazoe Shinji
Tajima Masamichi
Hepperle Stephen
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
SMC Corporation
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