Electricity: measuring and testing – Magnetic – Displacement
Reexamination Certificate
1999-10-13
2001-06-05
Patidar, Jay (Department: 2862)
Electricity: measuring and testing
Magnetic
Displacement
C324S207130, C137S556000
Reexamination Certificate
active
06242909
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a position indicator for a rotary valve actuator which is used to open or close a rotary valve, e.g., the type of indicator which is the subject of U.S. Pat. No. 5,957,158. More specifically, the invention is directed to apparatus for providing a visual and electrical indication of whether or not a rotary valve is in an open, closed, or intermediate position. Electrical indication is provided by novel means employing cams to engage spring-biased rods having magnets for actuating one or more magnetic switches.
It is known to use pneumatic and hydraulic pressure to operate a rotary valve actuator by applying fluid under pressure to a valve actuator through pneumatic or hydraulic fluid lines. For example, there is known in the art a type of rotary valve actuator having opposing pistons which are coupled to a rack and pinion mechanism for converting pneumatic or hydraulic pressure applied to the pistons to torque for opening and closing a rotary valve.
The rotary valve has a valve member which is directly connected to the output shaft of the rotary actuator and is selectively rotated into and out of the path of fluid flow between the inlet and outlet ports of a valve housing, between open and closed positions which are typically ninety degrees apart. Although the open or closed state of a rotary valve may be indirectly determined by sensing fluid pressure or flow downstream of the valve, it is desirable to have a direct indication of whether a valve is open or closed, and its exact position, independently of fluid flow through the valve. A direct indication of the operating position of a rotary valve can be provided from a visual observation of the angular position of the output shaft on the rotary valve actuator relative to a fixed reference, since the output shaft of the rotary valve actuator is directly connected to the valve member. However, often it is desirable to determine valve position from a remote location whereat the valve is not visible. The use of electric sensors on a valve to determine position has heretofore been limited due to adverse environmental effects on sensor circuitry.
SUMMARY OF THE INVENTION
The present invention overcomes the aforementioned problems of the prior art in providing a visual indicator which includes a combination visual and electrical valve position indicator. More specifically the invention provides for a position indicator having a stator with a central axis and a base, a rotor coaxially rotatably mounted on the stator, the rotor having a circumference with a plurality of angularly displaced, vertically offset, eccentricities. The rotor is provided with a plurality of stacked rings, each having one or more eccentricities on its surface. Each of the rings has an upper edge and a lower edge, there being meshing teeth on the upper edge and lower edge for removably interlocking adjacent stacked rings to prevent relative angular motion between them.
Actuators in one to one correspondence with the eccentricities are independently movably mounted relative to the base. Each one of the actuators has a cam surface engageable by a corresponding one of the eccentricities for moving the actuator to an active position when the rotor rotates to a predetermined position. Restoring springs are mounted between the actuator and the base for restoring each actuator to a rest position when the rotor rotates away from the predetermined position.
A plurality of magnetic switches in one to one correspondence with the actuators are fixedly mounted relative to the base in a hermetically sealed housing, each of the magnetic switches having a first state, e.g., open, in the absence of a magnetic field and a second state, e.g., closed, in the presence of a magnetic field. A magnet is mounted on each of the actuators for producing a magnetic field about a corresponding one of the magnetic switches thereby causing the magnetic switches to be in the second state when the actuator is in its active position, the magnetic switches being free of the magnetic field and in the first state when the actuator is in its rest position.
A decoder can be connected to each of the magnetic switches for producing a signal indicative of the position of the rotor relative to the stator.
It is therefore an object of the invention to provide an electronic indication of valve actuator position which can signal numerous positions.
Another object of the invention is to be able to change the positions of a valve actuator which can be sensed without exposing electrical sensing circuitry to the ambient environment.
Still another object of the invention is to sense valve actuator position without any mechanical linkage between the valve actuator and the sensing electronics which can cause exposure of electrical sensing circuitry to the ambient environment.
A further object of the invention is provide valve actuator position indication signals which can be applied to computer systems.
Other and further objects of the invention will be apparent from the following drawings and description of a preferred embodiment of the invention in which like reference numerals are used to indicate like parts in the various views.
REFERENCES:
patent: 4663601 (1987-05-01), troutman et al.
patent: 5621317 (1997-04-01), wozniak
patent: 5777471 (1998-07-01), stoll et al.
patent: 5957158 (1999-09-01), volz et al.
Dorsey Edward
Gardiner Kevin
LaMarca Drew
ASCO Controls, L.P.
Levine & Mandelbaum
Patidar Jay
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