Abstract: A rotary union includes a rotating seal carrier having a rotating seal member connected thereon, and a non-rotating seal carrier having a non-rotating seal member connected thereon. A piston portion of the non-rotating seal carrier has a flow restrictor ring disposed thereon, and both are slidably and sealably disposed within a piston bore formed in a housing. A gap is formed between an outer diameter of the flow restrictor ring and an inner diameter of the piston bore. The enlarged diameter of the piston portion provides a net pneumatic or hydraulic surface that can be acted upon by a fluid at a positive or negative atmospheric pressure present within the piston bore of the housing.

Abstract: A rotary union includes a rotating seal carrier having a rotating seal member connected thereon, and a non-rotating seal carrier having a non-rotating seal member connected thereon. A piston portion of the non-rotating seal carrier has a flow restrictor ring disposed thereon, and both are slidably and sealably disposed within a piston bore formed in a housing. A gap is formed between an outer diameter of the flow restrictor ring and an inner diameter of the piston bore. The enlarged diameter of the piston portion provides a net pneumatic or hydraulic surface that can be acted upon by a fluid at a positive or negative atmospheric pressure present within the piston bore of the housing.

Abstract: A rotary union includes a non-rotating machine component having a receiving counterbore, a media channel opening, and a control channel. A housing is positioned within the receiving counterbore and has a bore and a control chamber in fluid communication with the control channel. A non-rotating seal member is slidably and sealingly disposed within the bore in the housing and has a media channel in fluid communication with the media channel opening and the receiving counterbore. The non-rotating seal member can be selectively extended or retracted within the bore of the housing, such that selective engagement of a face seal is accomplished under different operating conditions of the rotary union.

Abstract: A rotary union includes a non-rotating machine component having a receiving counterbore, a media channel opening, and a control channel. A housing is positioned within the receiving counterbore and has a bore and a control chamber in fluid communication with the control channel. A non-rotating seal member is slidably and sealingly disposed within the bore in the housing and has a media channel in fluid communication with the media channel opening and the receiving counterbore. The non-rotating seal member can be selectively extended or retracted within the bore of the housing, such that selective engagement of a face seal is accomplished under different operating conditions of the rotary union.