ELECTRICAL GROUNDING OF BEARING SEAL

Abstract

A bearing seal includes a rotor and a stator and at least one electrically conductive elastomeric toroidal member. When the bearing seal is installed in equipment and is providing sealing between the rotor and the stator, an electrical grounding path is provided therebetween, the electrical grounding path extending through the electrically conductive elastomeric toriodal member.

Claims

1. A bearing seal for equipment having an equipment rotor and an equipment stator, said bearing seal comprising: a bearing seal rotor; a bearing seal stator; an electrically conductive elastomeric toroidal member so that, when said bearing seal is installed in equipment, said bearing seal provides sealing between the equipment rotor and said bearing seal stator; and, an electrical grounding path between the equipment rotor and the equipment stator, said electrical grounding path extending through said electrically conductive elastomer toroidal member.

2. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 1, wherein an additional electrically conductive elastomeric toroidal member is provided between the equipment rotor and said bearing seal rotor.

3. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 1, wherein an additional electrically conductive elastonneric toroidal member is provided between the equipment stator and said bearing seal stator.

4. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 1, further comprising a shut-off device for said bearing seal.

5. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 4, wherein said shut-off device includes an additional electrically conductive elastomeric toroidal member for providing an electrical conduction between said bearing seal rotor and said bearing seal stator.

6. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 1, wherein said electrically conductive elastomeric toroidal member is made of a silicone rubber.

7. The bearing seal for equipment having an equipment rotor and an equipment stator according to claim 6, wherein the silicone rubber is a two-component material.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURE

[0024] The unnumbered drawing FIGURE is a longitudinal section of one half of a labyrinth seal bearing protector of the present invention in a rotationally static position.

DETAILED DESCRIPTION OF THE DRAWING FIGURE AND PREFERRED EMBODIMENTS

[0025] The present invention will now be described, by way of example only, with reference to the accompanying drawing FIGURE.

[0026] Rotating equipment assembly 11 includes a rotating shaft 12 and stationary equipment housing 13. The equipment housing 13 generally contains a bearing (not shown) mounted in the radial space between the shaft 12 and housing 13.

[0027] Area X, adjacent to the bearing (not shown) and one axial end of the bearing protector assembly 10, generally contains bearing lubrication fluid, but could also contain solid and/or foreign debris and/or atmosphere. It will be referred to herein as product substance as being used to described the single or mixed medium.

[0028] Area Y at the other end of the bearing protector assembly 10 can also partially contain fluid, typically sprayed moisture and/or solids and/or foreign debris and/or atmosphere. It will herein be termed atmospheric substance being used to describe a single or mixed medium.

[0029] The bearing protector assembly 10 includes a rotor member 14, which is radially and longitudinally adjacent to stator member 16.

[0030] The stator member 16 is preferably rotationally attached to the equipment housing 13 by means of elastomeric toroidal member (e.g., O-ring) 17.

[0031] Rotor 14 is radially mounted in sealing engagement with shaft 12 by O-ring 18. A further O-ring 15 is also provided. The frictional squeeze on O-ring 15 is generally sufficient to transmit the rotational drive from the shaft 12 to rotor 14, however a separate drive mechanism could be employed to transmit the drive, if so required.

[0032] The static shut-off device 23 seals the rotor to the stator when the shaft is at rest/idle and provides a non-contact seal when the shaft is in operation.

[0033] Stator 16 incorporates a radially extending groove 28, which extends longitudinally from the innermost circumference and is substantially adjacent to the rotor or shaft 12, as shown. The groove is positioned adjacent to area X and the sealed media in the equipment bearing chamber 11. The groove 28 is circumferentially discontinued at the 6 oclock position by an orifice (not show) which communicates between area X and the outermost radial surface of the groove 28. The outermost surface of the radial stator 16 is circumferentially discontinued at the 6 oclock position by an orifice (not shown), which communicates between area Y and the innermost radial surface of the stator 16.

[0034] At least one of the two O-rings, 15, 18, is made of electrically conductive material. The O-ring 31 of the shut-off valve is also made of electrically conductive material. Furthermore, O-ring 17 is similarly made of electrically conductive material. As a result, an electrical path is provided between shaft 12 and housing 13. This path extends through one or both of O-rings, 15, 18, through the rotor 14, then through O-ring 31 of the shut-off valve through the stator 16 and, finally, through O-ring 17 before entering housing 13.

[0035] The above-mentioned electrically conducting O-rings are made of an electrically conducting HCR silicone rubber such as Elastosil R Plus 573/70 A/B made by Wacker Silicones. This material, which is a two-component silicone rubber, provides good mechanical and electrical properties. It has high conductivity, low volume resistivity, good heat resistance and good rheological properties. It has previously being proposed for use in such applications as EMI-gaskets, ignition cables (core) and band electrodes.

[0036] The general principle of rotary seals in accordance with the present invention may be used, not only in the case where the shaft is a rotary member and the housing is a stationary member, but also the reverse situation, that is to say, in which the shaft is stationary and the housing is rotary.

[0037] Furthermore, the invention may be embodied in both rotary and stationary arrangements, cartridge and component seals with metallic components, as well as non-metallic components.

[0038] While only several embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that many modifications may be made to the present invention without departing from the spirit and scope thereof.