Tandem packing for a reciprocating pump

Claim 2

A replaceable packing cartridge for sealing the annular spAce between a pump housing and a moveable member which comprises: a sleeve adapted to be detachably mounted to said housing in surrounding relation to said member and having an outer exposed portion and an inner end disposed adjacent said housing, said sleeve containing inner and outer packing assemblies and means for separately supporting said packing assemblies, said sleeve having formed therein a vent passage which extends from said exposed portion to the interior of said sleeve at a point between said packing assemblies; and means for selectively closing said vent passage whereby said pump in which said packing cartridge is mounted may be operated through a first stage with the vent passage open wherein the inner packing assembly provides the seal for said annular space and a second stage with the vent passage closed wherein the outer packing assembly provides the seal for said annular space.

Claim 3

A packing cartridge as defined in claim 1 wherein said inner packing assembly includes a plurality of self-energizing seal rings and a lantern ring interposed between two of said seal rings, and said sleeve has formed therein a lubricating passage which extends from said exposed portion to the interior of said sleeve and is in fluid communication with said lantern ring.

Claim 4

A packing cartridge as defined in claim 2 wherein said sleeve has formed therein a third passage for conducting a wash fluid which extends from said exposed portion to the interior of said sleeve at a point in advance of the seal rings of said inner packing.

Claim 5

A packing cartridge as defined in claim 3 wherein said sleeve includes a face seal between said inner end and the adjacent housing.

Claim 6

A replaceable packing cartridge for sealing the annular space between a pump housing and a pump plunger which comprises: a sleeve adapted to be detachably mounted on said housing in surrounding relation to said plunger and having an outer exposed portion and an inner end disposed adjacent said housing, said sleeve having formed therein an inner packing chamber and an outer packing chamber separated by a support shoulder; inner and outer packing assemblies mounted in said inner and outer packing chambers, respectively, each of said packing assemblies including a plurality of self-energizing seal rings, said inner packing assembly further including a lantern ring positioned between two of said seal rings thereof, said sleeve having formed therein a lubricating passage which extends from said exposed portion to said inner chamber and being in fluid communication with said lantern ring, and a vent passage which extends from said exposed portion and being in fluid communication with the interior of said sleeve at a point between the seal rings of said inner and outer packing assemblies; and means for selectively closing said vent passage whereby said pump containing said packing cartridge may be operated through a first stage with said vent passage open wherein said inner packing provides the plunger seal and through a second stage with said vent passage closed wherein said outer packing provides the plunger seal.

Claim 7

A replaceable packing cartridge for sealing the annular space between a pump housing and a pump plunger which comprises: a sleeve adapted to be detachably mounted on said housing in surrounding relation to said plunger and having an outer exposed portion and an inner end disposed adjacent said housing, said sleeve having formed therein an inner packing chamber and an outer packing chamber separated by a support shoulder; inner and outer packing assemblies mounted in said inner and outer packing chambers, respectively, each of said packing assemblies including a plurality of self-energizing seal rings, said inner packing assembly further including a lantern ring positioned between two of said seal rings thereof, said sleeve having formed therein a lubricating passage which extends from said exposed portion to said inner chamber and being in fluid communication with said lantern ring, and a vent passage which extends from said exposed portion and being in fluid communication with the interior of said sleeve at a point between the seal rings of said inner and outer packing assemblies; and means for selectively closing said vent passage whereby said pump containing said packing cartridge may be operated through a first stage with said vent passage open wherein said inner packing provides the plunger seal and through a second stage with said vent passage closed wherein said outer packing provides the plunger seal.

Claim 8

A packing cartridge as defined in claim 5 wherein said inner packing assembly further includes a spring for maintaining the rings of said inner packing in compression.

Claim 9

A packing cartridge as defined in claim 6 wherein said sleeve has formed therein a flow passage for conducting a wash fluid which extends from said exposed portion to said inner chamber at a point opposite said spring.

Claim 10

A packing cartridge as defined in claim 5 wherein said outer packing assembly further includes a lantern ring interposed between two of said seal rings thereof and said sleeve has formed therein a second lubricating passage which extends from said exposed portion to said outer chamber in fluid communication with said lantern ring of said outer packing.

Claim 11

A packing cartridge as defined in claim 5 wherein said inner and outer packing assemblies each include a spring for maintaining the rings thereof in comPression.