Actuator rod hermetic sealing apparatus employing concentric bellows and pressure compensating sealing liquid with liquid monitoring system

An apparatus providing a seal between an interior volume of an enclosure and an exterior environment of the enclosure, the apparatus providing the seal between a wall of the enclosure and an actuator rod mounted to the enclosure for movement of the rod relative to the enclosure, the rod extending from the exterior environment through an opening in the enclosure wall into the interior volume of the enclosure, the apparatus comprising:

• a housing secured the enclosure around the opening in the enclosure wall, the housing having an interior chamber and first and second openings through the housing to the interior chamber, the second opening adjoining the opening in the enclosure wall and communicating the interior chamber with the interior volume of the enclosure and the actuator rod extending from the exterior environment through the housing first opening, the interior chamber, the housing second opening and the opening in the enclosure wall into the interior volume of the enclosure;
• a seal between a circumference of the actuator rod and the housing first opening sealing the housing interior chamber from the exterior environment;
• a piston having opposite first and second end faces and a center bore extending between the first and second end faces, the bore being mounted over the circumference of the actuator rod with the piston contained in the housing interior chamber for reciprocating sliding movement of the piston on the actuator rod along a longitudinal axis of the rod and along a longitudinal length of the interior chamber;
• a first bellows connected between the piston and an interior surface of the housing chamber and a second bellows connected between the piston and the actuator rod, the first and second bellows and the piston separating the interior chamber into first and second areas and sealing the first and second areas from each other;
• means provided on the housing for sensing a position of the piston relative to the longitudinal length of the housing interior chamber and the actuator rod;
• and
• the housing interior chamber has at least one sidewall and the piston has a peripheral surface that longitudinally spaces the first and second piston end faces from each other and gives the piston a configuration of a truncated cone with one of the first and second end faces having a smaller diameter than the other of the first and second end faces, and the means for sensing the position of the piston relative to the longitudinal length of the housing interior chamber is a proximity sensor that senses a spacing between the peripheral surface of the piston and the sidewall of the housing interior chamber as the piston reciprocates along the longitudinal length of the housing interior chamber.

An apparatus providing a seal between an interior volume of an enclosure and an exterior environment of the enclosure, the apparatus providing the seal between a wall of the enclosure and an actuator rod mounted to the enclosure for movement of the rod relative to the enclosure, the rod extending from the exterior environment through an opening in the enclosure wall into the interior volume of the enclosure, the apparatus comprising:

• a housing secured to the enclosure around the opening in the enclosure wall, the housing having an interior chamber and first and second openings through the housing to the interior chamber, the second opening adjoining the opening in the enclosure wall and communicating the interior chamber with the interior volume of the enclosure and the actuator rod extending from the exterior environment through the housing first opening, the interior chamber, the housing second opening and the opening in the enclosure wall into the interior volume of the enclosure;
• a seal between a circumference of the actuator rod and the housing first opening sealing the housing interior chamber from the exterior environment;
• a piston having opposite first and second end faces and a center bore extending between the first and second end faces, the bore being mounted over the circumference of the actuator rod with the piston contained in the housing interior chamber for reciprocating sliding movement of the piston on the actuator rod along a longitudinal axis of the rod and along a longitudinal length of the interior chamber;
• a first bellows connected between the piston and an interior surface of the housing chamber and a second bellows connected between the piston and the actuator rod, the first and second bellows and the piston separating the interior chamber into first and second areas and sealing the first and second areas from each other;
• means provided on the housing for sensing a position of the piston relative to the longitudinal length of the housing interior chamber and the actuator rod;
• and
• the means provided for sensing a position of the piston relative to the actuator rod includes a sight glass mounted in the housing enabling viewing of the piston inside the housing interior chamber from the exterior environment.

An apparatus providing a seal between an interior volume of an enclosure and an exterior environment of the enclosure, the apparatus providing the seal between a wall of the enclosure and an actuator rod mounted to the enclosure for movement of the rod relative to the enclosure, the rod extending from the exterior environment through an opening in the enclosure wall into the interior volume of the enclosure, the apparatus comprising:

• a housing secured to the enclosure around the opening in the enclosure wall, the housing having an interior chamber and first and second openings through the housing to the interior chamber, the second opening adjoining the opening in the enclosure wall and communicating the interior chamber with the interior volume of the enclosure and the actuator rod extending from the exterior environment through the housing first opening, the interior chamber, the housing second opening and the opening in the enclosure wall into the interior volume of the enclosure;
• a seal between a circumference of the actuator rod and the housing first opening sealing the housing interior chamber from the exterior environment;
• a piston having opposite first and second end faces and a center bore extending between the first and second end faces, the bore being mounted over the circumference of the actuator rod with the piston contained in the housing interior chamber for reciprocating sliding movement of the piston on the actuator rod along a longitudinal axis of the rod and along a longitudinal length of the interior chamber;
• a first bellows connected between the piston and an interior surface of the housing chamber and a second bellows connected between the piston and the actuator rod, the first and second bellows and the piston separating the interior chamber into first and second areas and sealing the first and second areas from each other;
• means provided on the housing for sensing a position of the piston relative to the longitudinal length of the housing interior chamber and the actuator rod;
• and
• the mounting of the piston center bore over the circumference of the actuator rod restricts flow of a sealing fluid between the first and second end faces of the piston through the center bore and means are provided on the piston for conducting flow of the sealing fluid between the first and second piston end faces bypassing flow of sealing fluid through the piston center bore.

An apparatus providing a seal between an interior

• volume of an enclosure and an exterior environment of the enclosure, the apparatus providing the seal between a wall of the enclosure and an actuator rod mounted to the enclosure for movement of the rod between first and second positions of the rod relative to the enclosure, the rod extending from the exterior environment through an opening in the enclosure wall into the interior volume of the enclosure, the apparatus comprising:
• a housing secured to the enclosure around the opening in the enclosure wall, the housing having an interior chamber and first and second openings through the housing to the interior chamber, the second opening adjoining the opening in the enclosure wall and communicating the interior chamber with the interior volume of the enclosure and the actuator rod extending from the exterior environment through the housing first opening. the interior chamber, the housing second opening and the opening in the enclosure wall into the interior volume of the enclosure;
• a seal between a circumference of the actuator rod and the housing first opening sealing the housing interior chamber from the exterior environment;
• a piston having opposite first and second end faces and a center bore extending between the first and second end faces, the bore being mounted over the circumference of the actuator rod with the piston contained in the housing interior chamber for reciprocating sliding movement of the piston on the actuator rod along a longitudinal axis of the rod and along a longitudinal length of the interior chamber;
• and,
• a first bellows connected between the piston and an interior surface of the housing chamber and a second bellows connected between the piston and the actuator rod, the first and second bellows and the piston separating the interior chamber into first and second areas and sealing the first and second areas from each other, wherein both the first and second bellows are constructed of stacked pluralities of double-ply annular disks;
• and,
• the pluralities of double-ply annular disks are constructed of a nonmetallic material.

An apparatus providing a seal between an interior

• volume of an enclosure and an exterior environment of the enclosure, the apparatus providing the seal between a wall of the enclosure and an actuator rod mounted to the enclosure for movement of the rod relative to the enclosure, the rod extending from the exterior environment through an opening in the enclosure wall into the interior volume of the enclosure, the apparatus comprising:
• a housing secured to the enclosure around the opening in the enclosure wall, the housing having an interior chamber and first and second openings through the housing to the interior chamber, the second opening adjoining the opening in the enclosure wall and communicating the interior chamber with the interior volume of the enclosure and the actuator rod extending from the exterior environment through the housing first opening, the interior chamber, the housing second opening and the opening in the enclosure wall into the interior volume of the enclosure;
• a seal between a circumference of the actuator rod and the housing first opening sealing the housing interior chamber from the exterior environment;
• a piston having opposite first and second end faces and a center bore extending between the first and second end faces, the bore being mounted over the circumference of the actuator rod with the piston contained in the housing interior chamber for reciprocating sliding movement of the piston on the actuator rod along a longitudinal axis of the rod and along a longitudinal length of the interior chamber;
• a first bellows connected between the piston and an interior surface of the housing chamber and a second bellows connected between the piston and the actuator rod, the first and second bellows and the piston separating the interior chamber into first and second areas and sealing the first and second areas from each other;
• wherein both the first and second bellows are constructed of stacked pluralities of double-ply annular disks;
• and,
• a proximity sensor is mounted on the housing adjacent a sidewall of the interior chamber and is adapted to determine a distance between the sensor and a peripheral surface of the piston as the piston reciprocates along the longitudinal length of the housing interior chamber and to produce signals representative of the sensed distance;
• and
• the mounting of the piston center bore over the circumference of the actuator rod restricts flow of a sealing fluid between the first and second end faces of this piston through the center bore and means are provided on the piston for conducting flow of the sealing fluid between the first and second piston end faces bypassing flow of sealing fluid through the piston center bore.