Mechanical seal for movable joints of machines

Details Mechanical seal for movable joints of machines Mechanical seal for movable joints of machines

1996-04-24

1998-10-13

Reese, Randolph A.

Seal for a joint or juncture

Seal for well apparatus

For below ground apparatus

277361, 277375, 277511, 277589, F16J 1538

Patent

active

058201300

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to sealing devices, more specifically, to mechanical seals for movable joints of machines operating under an excess pressure.


BACKGROUND ART

It is common and widespread knowledge that reliable operation of movable joints in mechanisms performing rotary and/or reciprocating motion under an excess pressure requires higher pressure-tightness and working durability of such joints. This is attainable by providing a movable machine component with elastomer packing rings, e.g., rubber ones. However, such seals are liable to rapidly wear when operating in abrasive media and in those which dissolve elastomers. Moreover, elastomer seals function poorly at high differential pressures and high sliding speeds. All this restricts the field of their application.
More reliable are mechanical seals which comprise cylindrical rings made of an antifriction material. Such rings are lapped to each other and pressed against a shaft or a rod from the opposite directions; they are made of a nonelastomer material and have an eccentric hole. The rings are arranged in pairs so that the point on one ring most removed from its axis is opposite to the respective point on the other ring, and each pair of the rings is turned with respect to the preceding pair. The rings cooperate with an element of an elastomer material and can be positioned on, e.g., such an element (SU, A, 391,315).
However, in such seals one cannot determine the amount of angular displacement of one pair of rings with respect to the other pair, with the result that the fluid under a higher pressure finds its way to the zone of a lower pressure, which affects adversely both the pressure-tightness and the reliability of the seal.


DISCLOSURE OF THE INVENTION

It is a principal object of the invention to provide a mechanical seal that allows of reducing clearances in the movable joints of mechanisms in machines operating under an excess pressure, which in turn decreases the leaks of the working fluid and extends the seal service life.
The foregoing object is accomplished due to the fact that in a mechanical seal for movable joints of machines operating under an excess pressure, comprising at least two pairs of nonelastomer cylindrical rings ground to each other with their faces and having the outer surfaces eccentrically displaced, said rings themselves cooperating with an elastomer element and being turned in pairs with respect to each other, according to the invention, one of the surfaces of the elastomer element, an outer or an inner one, respectively, has eccentrically arranged shoulders or borings, while the seal rings have concentric cylindrical surfaces and are fitted on said shoulders or in said borings.
It is expedient that said shoulders or borings of said element be arranged in pairs and their axes be located on the opposite sides of the axis of said element, while the planes passing through the axes of the paired shoulders or borings be turned with respect to each other through an angle equal to 180
, where n is the number of pairs of the shoulders or borings.
Such a construction arrangement of the proposed seal enables one to establish an intricately shaped labyrinth-type sealing gap or groove, whereby a high hydraulic resistance is offered to the fluid flow from a high-pressure space to a low-pressure space. A higher hydraulic resistance is also favored by a many-times' repeated change in the direction of the fluid flow through the sealing gap.
All this as a whole reduces the fluid leaks and adds to the seal service life.


BRIEF DESCRIPTION OF THE DRAWINGS

In what follows the present invention is illustrated in a detailed description of some specific exemplary embodiments thereof with reference to the accompanying drawings, wherein:
FIG. 1 a longitudinal sectional view of a mechanical seal for a movable joint of a mechanism having a horizontal axis of rotation, according to the invention;
FIG. 2 is a section taken along the line II--II in FIG.1;
FIG. 3 is a view of an elastomer element provided with two

REFERENCES:
patent: 1560307 (1925-11-01), Peeler
patent: 2804050 (1957-08-01), Spilling
patent: 2863632 (1958-12-01), Miller
patent: 3442518 (1969-05-01), Henshaw
patent: 4292014 (1981-09-01), Lupke et al.
patent: 4702671 (1987-10-01), Brinkman et al.
patent: 5037115 (1991-08-01), Brandon
patent: 5433453 (1995-07-01), Dalton

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