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Mechanical seal with hydro-pad face profile
PATENTS with gas to effect the key sealing function, which occurs as a face seal arrangement. The embodiment removes or minimises various disadvantages associated with tandem and double-opposed seals. The subject embodiment enables the integration of porous media sealing into existing single, tandem, or double-opposed arrangements. In each of these arrangements there are numerous advantages over the prior art, and these are explained. Furthermore, a so-called ventless seal arrangement allows for zero emissions of process fluid, and also enables the use of clean process gas as the buffer to the ventless seal. Lastly, embodiments aim to eliminate seals altogether at the radial bearing locations by incorporating a ventless seal into the thrust bearing or balance piston. In all proposed arrangements, low flow rates of external gas are required, thus allowing for a significant reduction in the cost of injected gas. In addition, a drastic reduction in seal panel complexity results from the use of externally pressurised porous media as seals. Patent number: WO/2016/054084 Inventor: A.J. Devitt Publication date: 7 April 2016
Sealing ring Applicant: NTN Corp, Japan A sealing ring has been developed that is capable of maintaining low-torque for a long period. The sealing ring is fitted in an annular groove provided in one member of a housing that has a shaft hole, and a rotating shaft is inserted through this hole. The sealing ring partially protrudes from the annular groove to contact the surface of the other member, and slidably contacts an unsealed fluid-side sidewall surface of the annular groove to seal the annular gap between these members. The outer diameter of the ring is an inclined surface, which has an inclination angle by which the width of the ring decreases from the outer diameter side towards the inner diameter side, and in a portion of the inner diameter side, not protruding from the annular groove, there is provided a recess which is a portion not contacting the sidewall surface and is in contact with the inner circumferential surface of the ring. Patent number: WO/2016/052595 Inventors: K. Kakehi and T. Kondou Publication date: 7 April 2016
February 2017
Diaphragm air seal Applicant: Caterpillar Global Mining Equipment Llc, USA This disclosure focuses on a diaphragm air seal. It is designed to provide a seal between a cylindrical housing, such as an axle box, and a cylindrical body, such as a traction motor (disposed within the cylindrical housing). The diaphragm air seal includes a first flange, which has a first sealing surface that engages (to effect sealing action) with the cylindrical housing; a second flange, which has a second sealing surface that engages with the traction motor (again to effect sealing action); and an air seal body that extends between the flanges. The air seal body is formed from an elastomeric material and has an S-shaped transverse cross-section. An assembly includes the diaphragm air seal and further includes what is referred to as an air seal “weldment” that has a radial weldment flange, and an axial weldment flange extending axially outwards from the radial weldment flange so that the first flange of the diaphragm air seal is disposed on and engages with the radial weldment flange. Patent number: WO/2016/053856 Inventors: M.J. Orvedahl and S.T. Scheffen Publication date: 7 April 2016
Seal for a gap between an outer and inner cylindrical surface Applicant: Nuovo Pignone Srl, Italy This invention relates to a seal for a gap between an outer and inner cylindrical surface. The surfaces have a central axis, are coaxial and are arranged to rotate reciprocally. The seal itself comprises a plurality of plate elements stacked on one another in order to define a ring between the outer and inner cylindrical surface. Each plate has a concave and convex side. The convex side is adjacent to the concave side of the next plate. In this way the gaps between the plates are greatly reduced (even for small radii and large distances between the outer and the inner surfaces) and consequently, fluid leakage is also reduced. Another aspect of this invention relates to the design described above, in which the seal also consists of an elastic element placed externally on a ring defined by the plurality of plate elements. Advantageously, this elastic element provides a preload that keeps the
seal elements in contact with the rotating surface during the start-up phase and ensures that they remain stacked together. Patent number: WO/2016/055371 Inventor: L. Bergamini Publication date: 14 April 2016
Mechanical seal with hydro-pad face profile Applicant: John Crane Group Corp The arrangement disclosed provides a seal, which does not require external cooling, for a boiler feed pump. It is configured to operate without any separate cooling water delivery system. It is described as an “uncooled seal”. A rotary endface seal assembly to seal a fluid under pressure includes a pair of annular, mating ring, seal faces with one of the faces defining a sealing interface between radially inner and radially outer peripheral edges (36 & 38). A plurality of hydro-pad recesses (44) are formed radially inwards from the peripheral edge of one of the seal faces at the pressure side of the seal assembly, at peripherally spaced intervals, and a plurality of feeder grooves (60) are formed radially inwards from the same peripheral edge of the seal face, between at least some of the recesses. The radial extent of the feeder grooves is longer than the radial extent of the hydro-pad recesses. In one form, a feeder groove is disposed between adjacent hydro-pad recesses, whilst in another form, a feeder groove is disposed between adjacent pairs of hydro-pad recesses. Patent number: WO/2016/057394 Inventors: G. Fitzgibbon and E. Jahromi Publication date: 14 April 2016
A fragmentary plan view of the annular seal face of the primary ring, which is part of the seal assembly that forms the subject of patent WO/2016/057394. The arrangement disclosed provides a seal, which does not require external cooling, for a boiler feed pump.
Sealing Technology
15
Sealing ring Applicant: NTN Corp, Japan A sealing ring has been developed that is capable of maintaining low-torque for a long period. The sealing ring is fitted in an annular groove provided in one member of a housing that has a shaft hole, and a rotating shaft is inserted through this hole. The sealing ring partially protrudes from the annular groove to contact the surface of the other member, and slidably contacts an unsealed fluid-side sidewall surface of the annular groove to seal the annular gap between these members. The outer diameter of the ring is an inclined surface, which has an inclination angle by which the width of the ring decreases from the outer diameter side towards the inner diameter side, and in a portion of the inner diameter side, not protruding from the annular groove, there is provided a recess which is a portion not contacting the sidewall surface and is in contact with the inner circumferential surface of the ring. Patent number: WO/2016/052595 Inventors: K. Kakehi and T. Kondou Publication date: 7 April 2016
February 2017
Diaphragm air seal Applicant: Caterpillar Global Mining Equipment Llc, USA This disclosure focuses on a diaphragm air seal. It is designed to provide a seal between a cylindrical housing, such as an axle box, and a cylindrical body, such as a traction motor (disposed within the cylindrical housing). The diaphragm air seal includes a first flange, which has a first sealing surface that engages (to effect sealing action) with the cylindrical housing; a second flange, which has a second sealing surface that engages with the traction motor (again to effect sealing action); and an air seal body that extends between the flanges. The air seal body is formed from an elastomeric material and has an S-shaped transverse cross-section. An assembly includes the diaphragm air seal and further includes what is referred to as an air seal “weldment” that has a radial weldment flange, and an axial weldment flange extending axially outwards from the radial weldment flange so that the first flange of the diaphragm air seal is disposed on and engages with the radial weldment flange. Patent number: WO/2016/053856 Inventors: M.J. Orvedahl and S.T. Scheffen Publication date: 7 April 2016
Seal for a gap between an outer and inner cylindrical surface Applicant: Nuovo Pignone Srl, Italy This invention relates to a seal for a gap between an outer and inner cylindrical surface. The surfaces have a central axis, are coaxial and are arranged to rotate reciprocally. The seal itself comprises a plurality of plate elements stacked on one another in order to define a ring between the outer and inner cylindrical surface. Each plate has a concave and convex side. The convex side is adjacent to the concave side of the next plate. In this way the gaps between the plates are greatly reduced (even for small radii and large distances between the outer and the inner surfaces) and consequently, fluid leakage is also reduced. Another aspect of this invention relates to the design described above, in which the seal also consists of an elastic element placed externally on a ring defined by the plurality of plate elements. Advantageously, this elastic element provides a preload that keeps the
seal elements in contact with the rotating surface during the start-up phase and ensures that they remain stacked together. Patent number: WO/2016/055371 Inventor: L. Bergamini Publication date: 14 April 2016
Mechanical seal with hydro-pad face profile Applicant: John Crane Group Corp The arrangement disclosed provides a seal, which does not require external cooling, for a boiler feed pump. It is configured to operate without any separate cooling water delivery system. It is described as an “uncooled seal”. A rotary endface seal assembly to seal a fluid under pressure includes a pair of annular, mating ring, seal faces with one of the faces defining a sealing interface between radially inner and radially outer peripheral edges (36 & 38). A plurality of hydro-pad recesses (44) are formed radially inwards from the peripheral edge of one of the seal faces at the pressure side of the seal assembly, at peripherally spaced intervals, and a plurality of feeder grooves (60) are formed radially inwards from the same peripheral edge of the seal face, between at least some of the recesses. The radial extent of the feeder grooves is longer than the radial extent of the hydro-pad recesses. In one form, a feeder groove is disposed between adjacent hydro-pad recesses, whilst in another form, a feeder groove is disposed between adjacent pairs of hydro-pad recesses. Patent number: WO/2016/057394 Inventors: G. Fitzgibbon and E. Jahromi Publication date: 14 April 2016
A fragmentary plan view of the annular seal face of the primary ring, which is part of the seal assembly that forms the subject of patent WO/2016/057394. The arrangement disclosed provides a seal, which does not require external cooling, for a boiler feed pump.
Sealing Technology
15