Block and bleed valve for safety system

Claim 2

A valve device for selectively communicating a first port with second and third ports in one mode of valve operation and for communicating the second and the third ports with a fourth port blocking the first port in a second mode of valve operation, said device comprising: a housing having a valve chamber therein, said housing having first, second, third and fourth ports communicating with said valve chamber; a valve member disposed in slidable relation in said valve chamber for movement between a first position at which said valve is in said first operation mode and a second position at which said valve is in said first operation mode and a second position at which said valve is in said second operation mode; said housing and said valve member being provided with passage means communicating said first port with said second and third ports at said first position and communicating said second and third ports with said fourth port at said second position while shutting off said first port; and reset means comprising a piston slidably disposed through said housing having a piston head in said valve chamber at the end of said valve chamber communicating with said third port for engaging an end of said valve member to move said valve member back from said second to said first position.

Claim 3

A valve device in accordance with claim 1 including means for engaging said piston and tElescoping said piston into said housing resetting said valve member.

Claim 4

A valve device in accordance with claim 2 wherein said means for engaging said reset piston comprises a nut having a handle and threadable onto said housing over said reset piston.

Claim 5

A valve device for selectively communicating a first port with second and third ports in one mode of operation of said device and for communicating the second and third ports with a fourth port while shutting off the first port in a second mode of operation of the device, said valve device comprising: a housing having a cylindrical valve chamber therein, said housing having first, second, third, and fourth ports disposed radially relative to said valve chamber and spaced longitudinally along said chamber; a first internal annular seal means within said housing around said valve chamber between said first port and said second port; a second internal annular seal means within said housing around said valve chamber between said second port and said fourth port; a third internal annular seal means in said housing around said valve chamber between said fourth port and said third port; said housing having a first internal annular recess defining a flow passage between said first and second seal means communicating with said second port; said housing having a second internal annular recess around said valve chamber between said second and said third internal annular seal means communicating with said fourth port; a cylindrical piston-type valve member slidable in said valve chamber for controlling communication between said ports opening into said valve chamber, said valve member having an internal flow passage chamber, first flow means opening through said valve member into said internal flow passage, said first flow means communicating said first housing port with said first internal annular recess of said housing when said valve means is at a first position and said first flow means communicating said first and second internal annular flow passage means of said housing when said valve member is at a second position, and said valve member having a second flow means communicating with said central flow passage and having a cross sectional area less than said first flow means and being in communication with said third port at both positions of said valve member; said valve member communicating said first port with said second and third ports at said first valve member position and communicating said second, third and fourth ports together while isolating said first port at said second valve member position; and a reset piston slidably disposed through said valve housing and having a head end in said valve chamber between an end of said chamber and an end of said valve member in the portion of said chamber into which said third port opens for moving said valve member from said second position back to said first position to reset said valve device.

Claim 6

A valve device for selectively communicating a first port with second and third ports in one mode of operation of said device and for communicating the second and third ports with a fourth port while shutting off the first port in a second mode of operation of the device, said valve device comprising: a housing having a cylindrical valve chamber therein, said housing having first, second, third, and fourth ports disposed radially relative to said valve chamber and spaced longitudinally along said chamber; a first internal annular seal means within said housing around said valve chamber between said first port and said second port; a second internal annular seal means within said housing around said valve chamber between said second port and said fourth port; a third internal annular seal means in said housing around said valve chamber between said fourth port and said third port; said housing having a first internal annular recess defining a flow passage between said first and second seal means communicating with said second port; said housing having a second internal annular recess around said valve chamber between said second and said third internal annular seal means communicating with said fourth port; a cylindrical piston-type valve member slidable in said valve chamber for controlling communication between said ports opening into said valve chamber, said valve member having an internal flow passage chamber, first flow means opening through said valve member into said internal flow passage, said first flow means communicating said first housing port with said first internal annular recess of said housing when said valve means is at a first position and said first flow means communicating said first and second internal annular flow passage means of said housing when said valve member is at a second position, and said valve member having a second flow means communicating with said central flow passage and having a cross sectional area less than said first flow means and being in communication with said third port at both positions of said valve member; said valve member communicating said first port with said second and third ports at said first valve member position and communicating said second, third and fourth ports together while isolating said first port at said second valve member position; and a reset piston slidably disposed through said valve housing and having a head end in said valve chamber between an end of said chamber and an end of said valve member in the portion of said chamber into which said third port opens for moving said valve member from said second position back to said first position to reset said valve device.

Claim 7

A valve device in accordance with claim 4 including means connected with said housing for engaging and operating said reset piston to reset said valve member of said valve device from said second back to said first position.

Claim 8

A valve device in accordance with claim 5 wherein said reset means comprises an operator member connected with said housing and engageable with an extendable end of said reset piston to move said piston from said second back to said first position.