Elastic contact seal

Abstract

A mechanical seal comprising an elastomeric modified O-ring in combination backup rings typically made of a low friction material such as Teflon with matching surfaces to modified O-ring surface to provide low dynamic friction and meantime prevent seal extrusion due to high pressures and temperatures.

Claims

1. An elastomeric O-ring comprising an inner half and an outer half in cross section; said outer half comprising a substantially rectangular cross section defining a flat outer diametrical surface and; said inner half comprising a substantially semi-circular cross section and defining a rounded inner diametrical surface; steps are defined where the inner and outer halves meet approximately halfway between said inner and said outer diametrical surfaces on each side of said O-ring; said steps extend inwardly from said outer half to said inner half; said substantially semi-circular cross section of said inner half further comprising symmetrical flat radial surfaces defined between said rounded inner diametrical surface and rounded portions of said semi-circular cross section adjacent each step.

2. A system comprising; an elastomeric O-ring comprising an inner half and an outer half in cross section; said outer half comprising a substantially rectangular cross section defining a flat outer diametrical surface and; said inner half comprising a substantially semi-circular cross section and defining a rounded inner diametrical surface; steps are defined where the inner and outer halves meet approximately halfway between said inner and said outer diametrical surfaces on each side of said O-ring; said steps extend inwardly from said outer half to said inner half; said substantially semi-circular cross section of said inner half further comprising symmetrical flat radial surfaces defined between said rounded inner diametrical surface and rounded portions of said semi-circular cross section adjacent each step; and backup rings on both sides of said O-ring having matching surfaces to elastomeric modified O-ring between, but not including, said inner and outer diametrical surfaces.

Description

BRIEF DESCRIPTION OF THE INVENTION

(1) Having thus described the invention in general terms, references will now be made to the description below taken in conjunction with the accompanying drawings wherein:

(2) FIG. 1 is cross sectional view of Elastic Contact seal assembly 10 consisted of modified elastomeric O-ring with corresponding Teflon backups.

(3) FIG. 2 is frontal view of elastic contact seal assembly.

(4) FIG. 3 is a cross-sectional view A-A of elastic contact seal assembly.

(5) FIG. 4 shows cross sectional view of modified elastomeric O-ring.

(6) FIG. 5 is frontal diametrical view of modified elastomeric O-ring.

(7) FIG. 6 shows cross-sectional view of backup ring.

(8) FIG. 7 is frontal diametrical view of backup ring in FIG. 6.

(9) FIG. 8 shows a typical gland consisting of housing, shaft assembly and extrusion gap.

(10) FIG. 9 shows cross-sectional view of Elastic Contact seal assembly installed inside gland of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows an advantageous form of Elastomeric Contact mechanical seal 10, according to the invention consisting of the combination of a modified elastomeric O-ring FIG. 4 made of materials such as Viton or Nitrile having a rounded inside diameter circular surface 22 and a flat outside diameter surface 14 and in addition halfway between inner diameter to outer on each side of elastomeric modified O-ring there is an outwardly step 20 that interlocks with backup ring FIG. 6 inwardly step 18, it is desirable to minimize elastomeric contact at sealing point 22 against dynamic shaft surface 32, as pressure is acted upon Elastomeric Contact Seal assembly 10 inside gland 38, interlocking steps 18 and 20 prevent excessive flow of elastomer towards dynamic shaft surface 32 while preventing modified elastomeric O-ring of FIG. 4 from rotating inside groove 38 and keeping full contact between surface 14 of modified elastomeric O-ring against inside groove diameter surface 30.

(12) As best seen in FIG. 1, radius 26 of backup ring of FIG. 6 follows exact curvature 28 of modified O-ring FIG. 4 just below outwardly step 20 with interconnecting radii 26 and 28 blending with angle extending away from inwardly step towards modified elastomeric inside diameter surface 22 where is between 30 to 50 degrees, with similar curvature on opposite side of modified elastomeric O-ring of FIG. 4 creates a minimal contact of elastomeric modified O-ring surface 22 against dynamic shaft surface 32, with this, surface contact between modified elastomeric O-ring of FIG. 4 against dynamic shaft surface 32 is minimized and meantime surface 24 of backup ring FIG. 6 against dynamic shaft surface 32 is maximized, since PTFE has a much lower friction than elastomer the resultant frictional force between ELASTOMERIC CONTACT SEAL ASSEMBLY against dynamic shaft surface 32 is minimized accordingly.