Hydrostatic shaft seal

Claim 2

A hydrostatic shaft seal for a pressure system comprising a shaft; a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; and piston means surrounding said shaft exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing means away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member by direct contact therewith into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the system pressure is exceeded.

Claim 3

A hydrostatic shaft seal for a pressure system comprising a rotatable member; a non-rotatable sealing member mounted in spaced axial relation to said rotatable member for movement axially relative to said rotatable member into hydrostatic sealing relation with said rotatable member; and piston means surrounding said shaft biasing said sealing member and said rotatable member into spaced relation under a first force while the system pressure is below a predetermined critical value, said piston means being exposed to a second force arising from the system pressure and being oppositely directed to said first force whereby said sealing member is allowed to move toward said rotatable member in response to said second force exceeding said first force, said piston means including a stepped plunger coaxially movable of said sealing member, said plunger having said second force applied to one side thereof and a lower pressure applied to the opposite side thereof.

Claim 4

A hydrostatic shaft seal for a pressure system comprising a rotatable member; a non-rotatable sealing member mounted in spaced axial relation to said rotatable member for movement axially relative to said rotatable member into hydrostatic sealing relation with said rotatable member; and piston means surrounding said shaft biasing said sealing member and said rotatable member into spaced relation under a first force while the system pressure is below a predetermined critical value, said piston means being exposed to a second force arising from the system pressure and being oppositely directed to said first force whereby said sealing member is allowed to move toward said rotatable member in response to said second force exceeding said first force, said piston means including a stepped plunger coaxially movable of said sealing member, said plunger having said second force applied to one side thereof and a lower pressure applied to the opposite side thereof.

Claim 5

A hydrostatic shaft seal as set forth in claim 2 wherein said plunger is an annular piston.

Claim 6

A hydrostatic shaft seal as set forth in claim 2 wherein said lower pressure is atmospheric pressure.

Claim 7

A hydrostatic shaft seal for a pressure system comprising a rotatable member; a non-rotatable sealing member mounted in spaced axial relation to said rotatable member for movement axially relative to said rotatable member into hydrostatic sealing relation with said rotatable member; and separating means biasing said sealing member and said rotatable member into spaced relation, said separating means including an axially movable plunger for contacting said sealing member and at least one spring biasing said plunger towards said sealing member whereby when the system pressure is below a critical value said spring moves said plunger against said sealing member to move said sealing member from said rotatable member and when said system pressure is above said critical value said spring is compressed to allow said plunger to move away from said sealing member.

Claim 8

A hydrostatic shaft seal for a pressure system comprising a rotatable member; a non-rotatable sealing member mounted in spaced axial relation to said rotatable member for movement axially relative to said rotatable member into hydrostatic sealing relation with said rotatable member; and separating means biasing said sealing member and said rotatable member into spaced relation, said separating means including an axially movable plunger for contacting said sealing member and at least one spring biasing said plunger towards said sealing member whereby when the system pressure is below a critical value said spring moves said plunger against said sealing member to move said sealing member from said rotatable member and when said system pressure is above said critical value said spring is compressed to allow said plunger to move away from said sealing member.

Claim 9

A hydrostatic shaft seal for a pressure system comprising a shaft; a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing positiOn and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded; and a spring biasing said sealing member under said second force away from said rotatable member.

Claim 10

A hydrostatic shaft seal for a pressure system comprising a shaft; a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing positiOn and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded; and a spring biasing said sealing member under said second force away from said rotatable member.

Claim 11

A hydrostatic shaft seal for a pressure system comprising a shaft a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded; and a spring biasing said sealing member towards said rotatable member.

Claim 12

A hydrostatic shaft seal for a pressure system comprising a shaft a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded; and a spring biasing said sealing member towards said rotatable member.

Claim 13

A hydrostatic shaft seal for a pressure system comprising a shaft, a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded, said piston means including a plurality of plungers, a ring connected to said plungers coaxially of said sealing member and springs for biasing said plungers towards said sealing member to contact said ring with said sealing member to move said sealing member from said rotatable member when said system pressure is below said critical value.

Claim 14

A hydrostatic shaft seal for a pressure system comprising a shaft, a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded, said piston means including a plurality of plungers, a ring connected to said plungers coaxially of said sealing member and springs for biasing said plungers towards said sealing member to contact said ring with said sealing member to move said sealing member from said rotatable member when said system pressure is below said critical value.

Claim 15

A hydrostatic shaft seal for a pressure system comprising a shaft; a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded, said piston means including a plunger exposed to said first force on one side thereof, and a spring biasing said plunger on said opposite side against said first force, said plunger being coaxially movAble into contact with said sealing member when said system pressure is below said critical value to coaxially space said sealing member from said rotatable member.

Claim 16

A hydrostatic shaft seal for a pressure system comprising a shaft; a rotatable member on said shaft; a non-rotatable sealing member mounted for axial movement relative to said rotatable member between a non-sealing position and a sealing position with respect to said rotatable member; first means biasing said non-rotatable sealing member into said sealing position; piston means exposed to a first force arising from the system pressure and to an opposed second force biasing said sealing member away from said sealing position and to a pressure lower than the system pressure, said piston means biasing said sealing member into said non-sealing position when the system pressure is below a predetermined critical value and releasing said sealing member for movement under the influence of said first means into said sealing position when said critical value of the pressure is exceeded, said piston means including a plunger exposed to said first force on one side thereof, and a spring biasing said plunger on said opposite side against said first force, said plunger being coaxially movAble into contact with said sealing member when said system pressure is below said critical value to coaxially space said sealing member from said rotatable member.

Claim 17

A hydrostatic shaft seal as set forth in claim 1 wherein said piston means is an annular piston.

Claim 18

A hydrostatic shaft seal as set forth in claim 1 wherein said lower pressure is atmospheric pressure.