High pressure liquid rotary coupling with slip seal

An elongated slender rotatable coupling assembly having an input end and a relatively rotatable for transferring a high pressure cleaning liquid and comprising:

• a hollow cylindrical housing body carrying said input end,
• a tubular shaft member rotatable coaxially within the housing body and having a liquid input passage within and near one end of said housing body,
• said shaft member carrying said outlet end near a second end of the housing body,
• axially spaced bearing means between said shaft and said housing body to rotatably support said shaft near its ends coaxially within the housing body and to prevent axial movement of the shaft when the shaft is subject to high forwardly directed thrust forces from internal pressures on the seal members,
• means defining a sealed chamber enclosing said bearing means and a lubricant therefor between said housing body and said shaft,
• input means for transferring a high pressure liquid from said input end into said shaft member in sealed relationship with the input passage of the shaft,
• said input means including a high pressure sealing assembly within the housing body,
• said sealing assembly including a seal holder and first and second seal members,
• said seal holder being an annular member in a fixed axial position within the housing body in spaced relationship to the input end of the shaft,
• said first and second seal members being annular cylindrical members having abutting end faces and having inside diameters communicating with the liquid input passage of the shaft,
• said first seal member being made of an extrusion-resistant deformable material,
• said second seal member being made of hard wear resistant material,
• said seal holder being located transversely of the input end of the shaft and having a counterbored coaxial cylindrical recess enclosing the first seal member and partially enclosing the second seal member to maintain the seal members and the shaft in coaxial alignment and with the second seal member abutting the shaft in sealing relationship with the input passage of the shaft during high pressure transfer of liquid through the coupling assembly.

A dynamic high pressure liquid seal assembly between two relatively rotatable annular members having an axis for their relative rotation,

• one of said members having an annular sealing face transverse to said axis and coaxial with respect to said axis,
• the other of said members having a cylindrical seal retaining surface coaxial with said axis facing toward said axis,
• an annular rigid seat having opposite faces extending perpendicular to said axis and an outer cylindrical surface closely fitting within the cylindrical seal retaining surface of said other member with one of said opposite faces abutting said annular sealing face,
• an annular deformable seal member having opposite first and second faces extending perpendicular to said axis and an outer cylindrical surface closely fitting within the cylindrical seal retaining surface of said other member with the first of said opposite faces of the seal member abutting said annular sealing face,
• the second of said opposite faces of the seal member facing a body of high pressure liquid to be contained by said seal to be pressed solely by said liquid to force the seal member into engagement with said seat member and force the seat member into sealing engagement with said annular sealing face of said one member to prevent the high pressure liquid from escaping between said relatively rotatable members.