Switch position sensing device for use with valve operators

• US 4,672,310 A
• Filed: 11/01/1985
• Issued: 06/09/1987
• Est. Priority Date: 11/01/1985
• Status: Expired due to Fees

• Current Assignee: Crane Company
• Original Assignee: Movats Incorporated
• Inventors: Sayed, Edmond A.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Harvey, Jack B.
• Application Number:
  US06/794,301
• Time in Patent Office: 585 Days
• Field of Search: 324/133, 324/415, 324/418, 324/422, 340/524, 340/686, 340/687, 340/644, 137/551, 137/552, 137/554, 73/168
• US Class Current: 324/133
• CPC Class Codes: G08B 21/18 Status alarms G08B21/02 takes precedence
• CPC Class Codes: H01H 9/167 Circuits for remote indication
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

A switch position sensing device gives visual and recorded information as to the relative open and closed position of a monitored switch whether the monitored switch is found within an AC or DC circuit or a dead circuit and without disturbing the wiring of the switches primary circuit.

Claims

1. In combination:

valve operator switch circuit including a close-to-open circuit and an open-to-close circuit, each circuit including a limit switch, a bypass switch and a torque switch, each switch being independently opened and closed, and wherein current is allowed to flow only in the alternative through the close-to-open circuit and the open-to-close circuit to open the valve and close the valve respectively;

first power source supplying power to said close-to-open circuit and to said open-to-close circuit;

at least a first switch position sensing circuit attached in parallel across one switch of said limit switch, bypass switch and torque switch of either said open-to-close circuit or said close-to-open circuit,

said switch position sensing circuit comprising;

a second power supply for providing unidirectional current to a unidirectional branch between a positive pole and a negative pole;

first lead wire within said unidirectional branch connected to one side of said one switch of said valve operator switch circuit; and

second lead wire within said unidirectional branch connected to the other side of said one switch, whereby said one switch lies within two circuits, being said valve operator switch circuit and said switch position sensing circuit;

current triggered switch component positioned within said unidirectional branch in series with said one switch, said current triggered switch component comprising a first current conducting element lying within said unidirectional branch for conducting said unidirectional current and second normally open switch element lying within a third current conducting circuit for conducting current from a third power supply, which normally open switch element is closed in response to the presence of current flowing through said first current conducting element;

first transistor means positioned within said unidirectional branch for selectively directing current to said first current conducting element of said current triggered switch component when said first transistor means is in its "on" state;

second transistor means positioned within said unidirectional branch for selectively directing current around said current triggered switch component to bypass said first current conducting element when said second transistor means is in its on-state and said first transistor means is in its off-state;

circuit conditioning means within said unidirectional branch for turning said first transistor means to its on-state when said one switch is in a closed condition, including means for preventing turn-on of said second transistor means, and for turning said second transistor means to its on-state when said one switch is in an open condition, including means for preventing turn-on of said first transistor means;

said third current conducting circuit including said normally open switch element of said current triggered switch component in series with a voltage recording device and a voltage limiting element, and said third power supply providing power to said third current conducting circuit when said normally open switch element is closed,

whereby a predetermined voltage is recorded by the recording device of the third power circuit in response to the one switch of the valve operator circuitry being closed and no voltage is recorded through the third power circuit when the one switch is open.