Liquid dispenser with stem sealing system
A sliding stem seal assembly includes a stem having an outer surface and a seal slidably received on the stem. In one embodiment, the seal includes a flared end with inner and outer flanges. In some embodiments, the seal comprises low friction material, such as a TEFLON material for example. In one embodiment, the flared end is also provided with a recess and a cantilever spring, or finger members, tending to bias the inner and outer flanges to provide positive radial pressure for optimizing fluid sealing in low-pressure and zero-pressure modes while minimizing frictional forces in use.
1 . A sliding stem seal assembly comprising:
a valve configured to move between open and closed positions;
a stem including an outer surface and configured to move in a direction along its longitudinal axis to cause movement of the valve;
an actuator configured to cause movement of the stem;
a seal comprising a fluorocarbon polymer, wherein the seal is slidably received on the stem such that the stem is configured to move axially relative to the seal, wherein the seal comprises inner and outer sealing surfaces and at least one recess between the inner and outer sealing surfaces, wherein the inner sealing surface is adapted to contact the outer surface of the stem to provide a ring-like seal in use; and
at least one cantilever spring at least partially disposed in the recess.
2 . The sliding stem seal assembly of claim 1 , wherein the cantilever spring at least partially abuts the inner and outer sealing surfaces to provide a substantially constant load upon the inner and outer flanges.
3 . The sliding stem seal assembly of claim 1 , wherein the seal includes at least one edge adapted to hold the spring within the recess.
4 . The sliding stem seal assembly of claim 1 , wherein the cantilever spring is arranged in the recess in a general U-shape, and comprises a plurality of fingers connected end to end.
5 . The sliding stem seal assembly of claim 1 , wherein the seal comprises at least one of a polytetrafluoroethylene, fluorinated ethylene-propylene, ethylene tetrafluoroethylene, and perflouoroalkoxy.
6 . A fluid dispensing assembly comprising:
a main body including an inlet port adapted to communicate with a source of pressurized fluid and an outlet port adapted to dispense fluid from the main body;
a stem including an outer surface, wherein the stem is adapted to assist in regulating fluid between the inlet port and the outlet port;
a seal slidably received on the stem and comprising inner and outer walls each having an inner surface, the seal including at least one recess between the inner and outer walls and defined by the inner surfaces of the walls; and
at least one spring at least partially disposed in the recess, wherein the spring comprises a plurality of fingers.
7 . The fluid dispensing assembly of claim 6 , wherein the inner wall is adapted to contact the outer surface of the stem to provide a ring-like seal in use.
8 . The fluid dispensing assembly of claim 6 , wherein the spring at least partially abuts the inner and outer walls to provide a constant load upon the inner and outer walls.
9 . The fluid dispensing assembly of claim 6 , wherein the spring is arranged in a general U-shape.
10 . The sliding stem seal assembly of claim 6 , wherein the seal comprises at least one of TEFLON and an elastomeric polymer.
11 . A fluid dispenser comprising:
a main body including an inlet port adapted to communicate with a source of pressurized fluid and an outlet port adapted to dispense fluid from the main body;
a stem including an outer surface, wherein the stem is adapted to assist in regulating fluid between the inlet port and the outlet port;
a polytetrafluoroethylene seal slidably received on the stem and comprising inner and outer sealing surfaces, wherein the inner surface contacts the outer surface of the stem to provide a first seal and wherein the outer surface contacts a portion of 10 the main body to provide a second seal;
a manual actuator adapted to control movement of the stem and control the flow of fluid through the main body; and
a shut off actuator adapted to shut off the flow of fluid upon sensing a fill condition.
12 . The fluid dispenser of claim 11 , wherein the polytretra fluoro-ethylene seal further comprises a flared end having an inner flange defining the inner surface and an outer flange defining the outer surface.
13 . The fluid dispenser of claim 12 , wherein the polytretra fluoro-ethylene seal comprises a recess between the inner and outer flanges, and wherein the assembly further comprises a spring disposed in a recess of the polytretra fluoro-ethylene seal, the spring at least partially abutting the inner and outer flanges of the flared end to provide a constant load upon the inner and outer flanges, wherein the spring comprises multiple cantilever fingers connected end-to-end.
14 . The fluid dispenser of claim 13 , wherein the spring is arranged in a general U-shape.
15 . The fluid dispenser of claim 13 , wherein the spring is a cantilever spring.
16 . The fluid dispenser of claim 13 , wherein the polytretra fluoro-ethylene seal has at least two edges adapted to hold the spring within the recess.
17 . The fluid dispenser of claim 11 , wherein the first seal is at least substantially concentric with the second seal.
18 . The fluid dispenser of claim 11 , wherein the polytretra fluoro-ethylene seal includes a recess and wherein the assembly comprises a spring disposed within the recess.
19 . A fluid dispenser comprising:
a main body including an inlet port adapted to communicate with a source of pressurized fluid and an outlet port adapted to dispense fluid from the main body;
a stem including an outer surface, wherein the stem is adapted to assist in regulating fluid between the inlet port and the outlet port;
a seal comprising a friction-reducing material slidably received on the stem such that the stem is configured to move axially relative to the seal, wherein the seal comprises a flange and an inner sealing surface, wherein the inner surface contacts the outer surface of the stem to provide a first seal;
an energizing member disposed within the seal and configured to provide a radial force on the flange to maintain the inner surface of the seal in contact with the outer surface of the stem; and
a manual actuator adapted to control movement of the stem and control the flow of fluid through the main body;
20 . The fluid dispenser of claim 19 wherein the friction-reducing material comprises a fluorocarbon polymer.
21 . The fluid dispenser of claim 19 wherein the friction-reducing material comprises at least one of polytetrafluoroethylene, fluorinated ethylene propylene, ethylene tetrafluoroethylene, and perfluoroalkoxy.
22 . The fluid dispenser of claim 19 , wherein the friction reducing material has a coefficient of friction of less than or equal to 0.1 relative to the stem.
23 . The fluid dispenser of claim 19 , wherein the friction reducing material has a coefficient of friction of less than or equal to 0.05 relative to the stem, and wherein the stem comprises stainless steel.