John Crane Inc.

James R Wasser

Darin Merrill Rasmussen

Syed Niamathullah

Michael G Kalodimos

Tom Steigerwald

Dan Kozlowski

James P Netzel

Douglas J Volden

Prashanthi Tirunagari

Glenn G Pecht

Wei-Tang Lai

Gregory E Klostermann

Ralph P Gabriel

John P Czubek

Anca Vasilache

Robert Peter Rieger

Gregory E Klosterman

Wei Tang Lai

Mike G Kalodimos

A non-collapsible flexible sealing membrane (or bellows) for incorporation in a mechanical seal assembly and use in rotary shaft equipment. The sealing membrane includes a substantially radially outward extending first flange portion, which can be urged into an axially shiftable ring by a biasing mechanism. The sealing membrane further includes a substantially axially outboard extending second coaxial portion, substantially radially inward of the balance diameter of the seal. The horizontal portion is advantageously held fixed to a stub sleeve by an annular band. The angle between the vertical portion and the horizontal portion of sealing membrane enables directional control of the forces acting on stub sleeve and primary ring.

Non-collapsible flexible sealing membrane and seal assembly for rotary shaft equipment

A seal that can be used alone or as a containment seal for another seal includes a primary ring () and a mating ring (), the primary ring being axially shiftable relative to a rotating shaft () and the mating ring being axially fixable relative to the rotating shaft, a biasing mechanism () that urges the primary ring toward the mating ring, and an annular flexible sealing membrane (). The membrane includes a flange portion () disposed at least partially between the biasing mechanism and the primary ring, a coaxial portion () that is axially fixable relative to the shaft, and a flexible connection portion () positioned within a radially inward extent of the flange portion and connecting the flange portion to the coaxial portion. At least one of the mating ring and the primary ring includes grooves formed on a face thereof that cause the formation of a gas film to develop between the primary ring and the mating ring that keeps the primary ring and the mating ring from contacting each other in operation.

Non-pusher dry gas seal with sealing elastomer and systems utilizing same

A mechanical seal assembly adapted for arrangement around a rotating shaft of a pump has first and second seals. Both include primary and mating rings, biasing mechanisms and annular flexible sealing membranes. The two seals can have different seal balances or different biasing forces (or both) to allow the second seal to run dry for extended periods.

Non-pusher dry running seal with sealing elastomer as a backup in sliding seal system

A contacting mechanical end face seal for use in applications having slow shaft rotational speeds, such as mixers, agitators and reactors, includes at least one seal ring having a face with spiral grooves. Both hydrostatic and hydrodynamic lift characteristics in the seal are utilized to generate and maintain a seal gap having sufficient stiffness to prevent contact of the seal ring faces during operation. Specific characteristics, or combinations of them, include a land to groove ratio between 0.2-0.9, tapered groove surfaces which are inclined from the O.D. toward the dam, groove area to land area ratios greater than 1.5, a stepped groove having a greater depth at the O.D. relative to the depth adjacent the dam, alternating deep and shallow grooves, and groove area to dam area ratio in the interface greater than 1.2. Disposing the grooves in the axially movable primary ring and providing a greater sealing area for the opposing mating ring seal face limits angular load imbalance in the seal by maintaining the grooved area within the seal interface. The seal may be utilizable in both single or dual seal arrangements.

Gas lubricated slow speed seal

A mechanical end face seal of the non-contacting type includes a primary seal ring having a back section, a seal face section and a middle section between the seal face and the back sections, each primary ring section having a radial dimension, defined as the difference between the outermost radius and the innermost radius of said respective section, the radial dimension of the back section being in a ratio relative to said middle section of between about 1.5 to about 3.1, and more preferably of between about 1.9 to about 2.5, and most preferably about 2.0 to about 2.3. Additionally, the mating seal ring includes grooves extending from one seal ring circumference toward the other and terminating adjacent a dam at a radius R.sub.g, it is beneficial to have the boundary between the grooves and the dam have a radius R.sub.g slightly larger or smaller, within about 10%, than the outer radius of the middle section.

Pressure responsive primary ring for a non-contacting mechanical end

A double, back to back oriented mechanical end face seal arrangement for use in sealing pumps or other devices used in fluid transfer of toxic or corrosive fluid has an intermediate buffer fluid chamber into which a relatively inert gas, such as nitrogen, is provided for use as a buffer fluid, and is maintained at a pressure which exceeds the process fluid pressure by at least 10 p.s.i. Each seal has a primary ring and a mating ring with gap maintaining means, such as spiral pumping grooves, formed in one of the rings which are shaped and dimensioned to pump the buffer gas through the first seal from the intermediate chamber into the process fluid chamber against the process fluid pressure and through the second seal from the intermediate chamber into the environment external to the housing and sealing area, thus avoiding the escape of the process fluid into the intermediate buffer chamber and thereby to the atmosphere. The inboard seal includes a first secondary sealing means disposed between one seal ring and the housing for sealing therebetween and a second secondary sealing means, disposed between the other seal ring and the shaft for sealing therebetween, the first and second secondary sealing means, which may comprise O-rings, each defining the boundary between the intermediate chamber and the process fluid chamber. The first and second secondary sealing means of the first rotary mechanical end face seal are sized and disposed to define radial walls in the back radial surfaces of each seal ring to thereby present essentially an equal area at an approximately identical radius, such that essentially the same mount of buffer fluid pressure acts on the back radial surfaces of each ring of the first rotary mechanical and face seal but in opposite directions and, on the process fluid side, the identical process fluid pressure acts on opposite sides of a portion of the respective rings of the first rotary mechanical end face seal essentially eliminating thrust forces acting on the first rotary mechanical end face seal.

Gas lubricated barrier seal

A mechanical end face seal of the non-contacting type includes a primary seal ring having a back section, a seal face section and a middle section between the seal face and the back sections, each primary ring section having a radial dimension, defined as the difference between the outermost radius and the innermost radius of said respective section, the radial dimension of the back section being in a ratio relative to said middle section of between about 1.8 to about 2.8, and more preferably of between about 1.9 to about 2.5, and most preferably about 2.0 to about 2.3. Additionally, the mating seal ring includes grooves extending from one seal ring circumference toward the other and terminating adjacent a dam at a radius R.sub.g, it is beneficial to have the boundary between the grooves and the dam have a radius R.sub.g slightly larger or smaller, within about 10%, than the outer radius of the middle section.

Pressure responsive primary ring geometry for a non-contacting

A mechanical end face seal with a mating ring having a beveled inner diameter extending frusto-conically to the back face. Atmosphere or other fluids located outside of the housing can enter through the frusto-conical opening between the primary ring and the shaft to cool the seal rings during shaft rotation. In a preferred embodiment, a drive collar disposed adjacent the primary ring and attached to the shaft includes a series of cantilever projection portions which rotate in the atmosphere outside the housing to circulate the atmosphere into the frusto-conical space between the beveled inner diameter of the stationary mating ring to provide a fan blade effect.

Mechanical end face seal having an improved mating ring

A double, back to back oriented mechanical end face seal for use in sealing toxic or corrosive fluids having an intermediate buffer fluid chamber into which a relatively inert gas, such as nitrogen, is provided for use as a buffer fluid. The nitrogen gas is maintained at a pressure which exceeds the process fluid pressure by at least 10 p.s.i. and, in a preferred embodiment, spiral pumping grooves in the mating rings of each of the seals are shaped and dimensioned to pump the nitrogen buffer gas through the first seal from the intermediate chamber into the process fluid chamber and through the second seal from the intermediate chamber into the environment external to the housing and sealing area, thereby avoiding the escape of the process fluid into the intermediate buffer chamber and to the atmosphere. Contamination of the process fluid by the buffer gas may be tolerated. The buffer gas may be any relatively inert gas, a gas which is non-hazardous to the environment and also is compatible with the process fluid used; appropriate examples are nitrogen, carbon dioxide, air or one of the noble gases. The seal can be used to seal a process fluid which is either a liquid or a gas.

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Gurnee, IL, United States of America

James R Wasser