Valves and valve actuation – Fluid actuated or retarded – Piston type expansible chamber reciprocating valve actuator
Reexamination Certificate
2000-08-31
2001-12-11
Huson, Gregory L. (Department: 3751)
Valves and valve actuation
Fluid actuated or retarded
Piston type expansible chamber reciprocating valve actuator
C251S118000, C251S120000, C251S144000
Reexamination Certificate
active
06328278
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an outlet valve arranged in the bottom of a vessel intended to be filled with liquid comprising a valve disc connected to a piston rod and a piston actuated by a pressure medium. The valve disc is movable between a first and a second position and is arranged to bear against a valve seat in a first closed position.
BACKGROUND OF THE INVENTION
Outlet valves of this kind are usually arranged in a conduit out from the vessel, which means that special measures to protect the piston, which is actuated by pressure medium, from the liquid are not necessary.
However, if the valve is arranged in a vessel where the liquid freely flows past the outlet opening the valve mechanism is usually arranged outside the vessel and the movement of the valve disc takes places using different arrangements for the power transmission.
SUMMARY OF THE INVENTION
The outlet valve according to the invention is mainly characterized in that the piston which controls the movements of the valve disc is arranged in an operating device provided with a connection to a source for pressure medium. The operating device is arranged as a unit, the interior of which is sealed against the liquid and is arranged at such a distance from the valve seat that the liquid when leaving the vessel passes a zone between the operating device and the valve seat. According to the invention the operating device may be located above the valve seat, that is maybe submerged in the liquid, as well as below the valve seat, that is located under the bottom of the vessel. The outlet valve according to the invention is designed such that the operating device is provided with two connections to the source for pressure medium, which connections lead to spaces in the operating device located on each side of the piston. With such a design both opening and closing of the valve are carried through by means of the pressure medium, which ensures a safe operation.
The valve according to the invention may advantageously be used for difficult applications, for example in vessels with liquid at a very high temperature. In such circumstances one can not rely on the working of a spring, since the carrying power of the spring may be affected by the heat.
According to the invention the operating device is advantageously connected to the valve seat. In this way there is obtained a solid unit which secures a movement of the piston, the piston rod and the valve disc, which is free from disturbances.
The valve according to the invention is advantageously designed such that the valve disc in the open position is situated on such a distance from the valve seat that the outlet opening is completely free. With such an arrangement a rapid emptying of the vessel is made possible.
If the operating device is arranged below the valve seat a shielding sheet in the shape of the cone is suitably arranged around the piston rod in the part which is turned towards the operating device. With such an arrangement both the piston rod and the operating device are protected and the liquid is led away from said part of the valve.
The valve disc is advantageously provided with a tube shaped part which concentrically surrounds the piston rod. This part surrounds also a second tube part firmly connected to the said cone shaped shielding sheet in the closed position of the valve. In this way it is avoided that possible particles in the liquid may hinder the movement of the piston rod.
Suitably the piston comprises piston rings separated by one or several sliding rings. These sliding rings may be produced of graphite impregnated teflon.
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patent: 6113064 (2000-09-01), Hillstrom
patent: 186479 (1956-08-01), None
patent: 2359316 (1975-06-01), None
Alfa Laval AB
Fish & Richardson P.C.
Huson Gregory L.
Nguyen Tuan
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