Fluid handling – Systems – Flow path with serial valves and/or closures
Reexamination Certificate
1999-06-07
2001-01-23
Lee, Kevin (Department: 3753)
Fluid handling
Systems
Flow path with serial valves and/or closures
C137S614040, C251S175000, C251S149600
Reexamination Certificate
active
06176263
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit breaker for an installation handling fluid under pressure such as a gas or a liquid, in particular water, freon, an oil, etc . . .
2. Discussion of the Related Art
It is known to produce a circuit breaker comprising two elements, male and female, adapted to fit axially in each other, causing an internal valve to open. Such a valve is generally provided with an O-ring intended to ensure seal between the valve and a sealing body disposed around the valve when the valve is in closed position.
Such a circuit breaker is shown in accompanying
FIGS. 7
to
9
, these Figures corresponding to three successive positions of the elements constituting the circuit breaker when the male and female elements are coupled. O-rings J
1
and J
2
are respectively provided, around a mobile valve C and a piston P for maneuvering this valve, to abut against sealing surfaces of a connector E or of the piston P. Taking into account the pressure P
0
prevailing around the valve C in the position of
FIGS. 7 and 8
, the O-ring J
1
, tends to be driven from the housing L made on the periphery of the valve C and to slide up to around the piston P, as shown in
FIG. 9. A
similar dislocation may occur during an opening of the circuit breaker. This operational defect is unacceptable, since the seal between the valve and the connector is in that case no longer ensured, due to the absence of the O-ring J
1
.
When the male connection, located to the left in
FIGS. 7
to
9
, is connected to a source of pressure, while the female connection is connected to a fluid-consuming installation, the difference in pressure is reversed with respect to that shown in
FIGS. 7
to
9
and the risk of dislocation principally concerns joint J
2
.
In any case, as soon as the difference in pressure between the two conduits connected to the male and female elements attains a critical value, one of the joints risks being ejected. This critical value depends on the fluid, on the nature of the joint and on the geometry of the elements constituting the circuit breaker. It may be less than
5
bars for circuit breakers used conventionally, with the result that the danger of ejection of a joint is present under the normal conditions of use of the circuit breaker.
In order to overcome this drawback, it may be provided to mold the joint in a housing of the dove-tail type, to crimp the joint or to effect an assembly with the aid of two pieces which imprison the joint. These solutions are expensive and require a more complex assembly, thus increasing manufacturing time. These solutions also render the foreseeable maintenance operations on the circuit breaker delicate.
It is a particular object of the present invention to overcome these drawbacks, by proposing a circuit breaker in which the risks of ejection of a joint with respect to its accommodating housing are very substantially reduced, if not eliminated.
SUMMARY OF THE INVENTION
To that end, the invention relates to a circuit breaker for an installation handling fluid under pressure comprising an internal valve, at least one joint in substantially toroidal form, or O-ring, being disposed in an accommodating housing around the valve and/or a member for maneuvering the valve, characterized in that this housing is connected, via at least one fluid-circulation channel, to a counter-pressure zone formed downstream of the joint around the valve or the maneuvering member.
Thanks to the invention, the pressure prevailing in the counter-pressure zone may exert on the joint an effort with a centripetal component tending to return it towards the inside of its accommodating housing, which makes it possible to balance the possible forces tending to drive the joint from its housing.
According to a first advantageous aspect of the invention, during a transitory phase of opening of the valve, a circuit for preferential flow of the fluid is arranged between this housing and this counter-pressure zone, through said channel. Thanks to this aspect of the invention, the counter-pressure prevailing in the counter-pressure zone presents a sufficient value to balance the supply pressure of the circuit breaker.
According to another advantageous aspect of the invention, the preferential flow circuit presents such a geometry that the pressure drops that it induces on the fluid during flow are less than the pressure drops induced on this fluid by a principal flow circuit of the fluid defined between the valve, the maneuvering member and/or a sealing body. Such distribution of the pressure drops guarantees the creation of a counter-pressure in the counter-pressure zone prior to the circulation of the fluid towards the downstream part of the circuit breaker during an opening of the valve, which makes it possible to create the counter-pressure before the forces on the joint tend to drive it from its housing. In that case, the principal flow circuit of the fluid may provided with obstacles adapted to increase the pressure drops induced on the fluid. Such obstacles are advantageously formed by annular grooves disposed on at least one of the opposite faces of the maneuvering member, the valve or the sealing body located downstream of the joint.
According to another aspect of the invention, the cross-section of passage of the preferential flow circuit is greater than the corresponding cross-section of passage of a principal flow circuit of the fluid defined between the valve, the maneuvering member and/or a sealing body. According to another approach, it may be provided that, under the same conditions, the total length of the preferential flow circuit is shorter than the corresponding length of the principal flow circuit.
According to another advantageous aspect of the invention, the housing is connected to the counter-pressure zone via a plurality of fluid circulation channels distributed around the axis of displacement of the valve. This multiplicity of channels allows a good distribution of the counter-pressure zone and of the effort exerted on the joint around this axis.
According to another advantageous aspect of the invention, the housing is connected, via at least one fluid circulation channel, to a pressurized fluid zone formed upstream of the joint. This second channel makes it possible to supply fluid under pressure to the internal volume of the housing, then the first circulation channel and the counter-pressure zone, whatever the positioning of the joint inside the housing. In that case, it may also be provided that the housing is connected to the pressurized fluid zone via a plurality of fluid circulation channels distributed about the axis of displacement of the valve.
REFERENCES:
patent: 5771927 (1998-06-01), Johansen et al.
patent: 1039178 (1953-10-01), None
patent: 581087 (1946-10-01), None
Lacroix Jean-Jacques
Pavan Andr{acute over (e)}
Dowell & Dowell PC
Lee Kevin
Staubi Faverges
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