Fluid handling – Systems – Valves with separate – correlated – actuators
Reexamination Certificate
1998-12-28
2001-05-01
Walton, George L. (Department: 3753)
Fluid handling
Systems
Valves with separate, correlated, actuators
C137S487500, C137S613000, C137S637300, C137S637400, C251S129110
Reexamination Certificate
active
06223774
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a redundant regulation valve for controlling the flow of a fluid, the valve comprising a valve body defining a fluid flow passage and a main throttle element movable by means of a main control device to close said passage selectively.
PRIOR ART
FIG. 5
is a diagram of a hydraulic installation having full redundancy for controlling selective flow of a fluid in a circuit comprising main pipes
10
and
13
. In that redundant system, two parallel pipes
11
and
12
are interposed between the main pipes
10
and
13
, and each parallel pipe has interposed therein a series connection of a stop valve
21
(or
22
) and a regulation valve
31
(or
32
).
The circuit shown diagrammatically in
FIG. 5
does indeed provide total redundancy by complete duplication of all of the equipment (stop valve and regulation valve), but it suffers from major drawbacks, insofar as the system is bulky, having elements that lead to large mass, thereby making it unsuitable, particularly in space applications.
The totally redundant circuit is also expensive and can be difficult to implement when there are difficult transient stages within a regulated system.
Proposals have also been made, as shown diagrammatically in
FIG. 6
, to use a regulation valve with a valve body
3
defining a flow passage
4
for a fluid that can be shut off by a selective shutter system comprising a throttle bar
1
A capable of moving linearly in the passage
4
to come into abutment in a fixed groove
1
C in the valve body
3
under drive from a control device
1
B. In order to increase safety without significantly increasing mass or cost, the control device
1
B is redundant, i.e. it has its control members in duplicate so that a substitute element can come into action in the event of an initial element of the control device
1
B failing.
Such redundancy of the control members only is easy to implement and makes the assembly more reliable, however it does not provide a solution to the case where the throttle element
1
A itself turns out to be faulty, e.g. because it jams. Unfortunately, such a failure can have catastrophic consequences in certain applications.
OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION
The invention seeks to remedy the above-mentioned drawbacks and to enable operating safety of a fluid regulation valve to be increased without significantly increasing the complexity or the bulk of the system, and while retaining low mass and reasonable costs in manufacturing, assembling, and operating the equipment as a whole.
These objects are achieved by a redundant regulation valve for controlling fluid flow, the valve comprising a valve body defining a fluid flow passage, and a main throttle element that is movable by means of a main control device to selectively obstruct said passage, the valve further comprising a redundant throttle element movable by means of a redundant control device, wherein in the closed position of the valve, in normal operation, the main element and the redundant element are in contact with each other, wherein in said normal closed position, the main element is in the vicinity of its position of maximum displacement in the closure direction and obstructs only about half of the passage, while the redundant element is in a medium displacement position, and wherein the stroke of the redundant element is such that the redundant element can be controlled to obstruct the passage even when the main element is in its fully-open position.
More particularly, the main throttle element or the main control device is associated with an abutment device that acts in the fully-open position and in the normally closed position of the valve, and the redundant throttle element or the redundant control device is associated with an abutment device that acts in the fully-open position of the main throttle element and in the emergency closure position of the redundant throttle element.
In a particular embodiment, the main control device comprises an electric motor and a screw-and-nut assembly driving the main throttle element.
Similarly, the redundant control device comprises an electric motor and a screw-and-nut assembly driving the redundant throttle element.
In an aspect of the invention, the main control device is associated with a regulation loop, comprising:
a) means for causing the main element to open in compliance with a controlled relationship until it reaches its nominal open position;
b) means for acting when said nominal open position is reached, to servo-control the position of the main element to a predefined parameter associated with a member fed by the flow of fluid through the valve; and
c) means for causing the main element to close in compliance with a second controlled relationship and which ensures end-of-stroke braking of the main element coming into abutment against the redundant element.
More particularly, the regulation loop associated with the main control device and with the redundant control device further comprises:
d) means for detecting that opening of the main element is not in compliance with said first controlled relationship;
e) means for controlling displacement of the redundant element in the event of non-compliance with said first controlled relationship during opening of the main element;
f) means for detecting non-compliance of the servo-control of the main element with said predefined parameter;
g) means for servo-controlling displacement of the redundant element in the event of non-compliance of said servo-control of the main element.
h) means for detecting non-compliance of the closure of the main element with said second controlled relationship; and
i) means for causing the displacement of the redundant element in the event of non-compliance with said second controlled relationship during closure of the main element.
In a first embodiment, the main throttle element and the redundant throttle element are respectively constituted by a main throttle bar and by a redundant throttle bar in axial alignment and axially movable in translation respectively by means of the main control device and by means of the redundant control device.
In a particular embodiment, the axially-aligned main bar and redundant bar are in contact in the normal closed position via annular plane front surfaces.
In another particular embodiment, the axially-aligned main bar and redundant bar are in contact in the normal closed position via conical or bullet-shaped circularly symmetrical surfaces.
In yet another particular embodiment, the main bar and the redundant bar are coaxial and partially engaged one in the other.
In which case, advantageously, the main bar has internal channels allowing the flow to pass through and opening out radially via openings passing through the cylindrical wall of said main bar, gaskets are interposed between the coaxial cylindrical surfaces of the main bar and of the redundant bar, and at least one of the radial openings of the main bar is selectively obstructable by the cylindrical wall of the redundant bar in which the main bar is engaged.
In another embodiment, the main throttle element and the redundant throttle element are respectively constituted by a main throttle bar and by a redundant throttle bar which are in axial alignment and which are provided with throttle flaps movable in rotation respectively by means of the main control device and by means of the redundant control device.
According to a particular characteristic, the valve includes shock absorber devices disposed at the interfaces between the main control device and the main throttle element, and between the redundant control device and the redundant throttle element.
REFERENCES:
patent: 923526 (1909-06-01), Houser
patent: 1378405 (1921-05-01), Farmer
patent: 1447652 (1923-03-01), Farmer
patent: 2059364 (1936-11-01), Kimball
patent: 2141614 (1938-12-01), Mott
patent: 3240466 (1966-03-01), Meyer
patent: 3280842 (1966-10-01), Weisenbach
patent: 3375849 (1968-04-01), Swartz
patent: 3757820 (1973-09-01), Aylesworth
patent: 4498471 (1985-02-01), Kranz
Fournier Jean-Pierre
Languedoc Christian
Meyer Francis
Salze David
Societe Nationale d'Etude et de Construction de Moteurs d&a
Walton George L.
Weingarten, Schurgin Gagnebin & Hayes LLP
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