Differential pressure switch
AssigneeDonaldson Company, Inc.
InventorJack Stifelman
Life of this patent
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Abstract
A differential pressure switch is disclosed. The switch functions through a conductive path formed within the fluid of a single cavity of a housing having passages for communicating high and low pressure fluid to the cavity. The switch has a cantilevered post with movable conducting and nonconducting members mounted thereabout and being movable between conductive and nonconductive states according to the differential pressure within the cavity. One of the movable members provides sealing between the post and the cavity wall to separate the high and low pressure fluids.
Claims20
Switch apparatus in combination comprising:
- a housing connected electrically to ground, said housing having a cavity therein;
- a post connected conductively to an electrical source;
- means for supporting said post cantilevered within the cavity, said supporting means including means for sealing said cavity between said post and said housing;
- means for communicating high pressure fluid to said cavity;
- means for communicating low pressure fluid to said cavity;
- means, guided by said post, for maintaining separation between said high and low pressure fluids within said cavity;
- means for biasing said separation maintaining means against said high pressure;
- and
- means for disconnectably connecting electrically said post and said housing.
A differential pressure switch for installation in a cavity of a grounded housing, said housing including means for communicating high and low pressure fluid into the cavity, said switch comprising:
- a central post for connection to an electrical energy source, said post having outer and inner ends;
- means for sealably fastening said post near the outer end to said housing, said fastening means providing support to cantilever the inner end of said post within said cavity;
- and
- means, mounted on the cantilevered portion of said post, for disconnectably connecting electrically said post and said housing, said connecting means including means for separating the high and low pressure fluids in said cavity.
A differential pressure switch for installation in a cavity of a grounded housing, said housing including first and second means for communicating first and second fluids into the cavity, said switch comprising:
- a terminal post for connection to an electrical energy source;
- means for supporting said post to cantilever an end of said post within the cavity, said supporting means including a threaded plug with first means for sealing between said housing and said plug, said supporting means including means for electrically insulating said plug from said post;
- a piston with a central opening therethrough for receiving said post, said piston retaining second means for sealing between said piston and said post and third means for sealing between said piston and said housing, said piston being mounted on said post between said first and second fluid communicating means;
- means for disconnectably forming an electrical path between said post and said housing, forming means including a spring received about said post;
- whereby differential pressure between the first and second fluids on opposite sides of said second and third sealing means causes movement of said piston thereby causing the conductive path of said forming means to be one of open and closed.
A differential pressure switch for installation in a cavity of a grounded housing, said housing including means for communicating high and low pressure fluid into the cavity, said switch comprising:
- a central post for connection to an electrical energy source;
- means for supporting said post cantilevered within the cavity, said supporting means including means for sealing said cavity between said post and said housing;
- means, supported by said post, for separating said high and low pressure fluids within said cavity;
- and
- means for disconnectably closing a conductive path between said post and said grounded housing, said closing means including first and second movable members mounted on said post and means for biasing said members for disconnectably closing the conductive path through one of said first and second members, said biasing means being received about said post.
A differential pressure switch for installation in a cavity of a grounded housing, said housing including means for communicating high and low pressure fluid into the cavity, said switch comprising:
- a central post for connection to an electrical energy source;
- means for supporting said post to cantilever an end of said post within the cavity, said supporting means including a threaded plug with first means for sealing between said housing and said plug, said supporting means including means for electrically insulating said plug from said post;
- a piston with a central opening therethrough for receiving said post, said piston retaining second means for sealing between said piston and said post and third means for sealing between said piston and said housing;
- a spacer with a central opening therethrough for receiving said post, said spacer being between said piston and said plug;
- a coil spring about said post between said supporting means and said spacer for biasing said piston and said spacer against high pressure fluid;
- and
- one of said piston and said spacer being conductive and the other being nonconductive;
- whereby said switch has a first state with a conductive path between said post and said housing and a second state wherein said post is insulated from said housing.
Dependencies are inferred from the claim text.