PRESSURE TRANSMITTER

COMMUNICATEUR DE PRESSION

English Abstract

V. N. Lawford - 13
PRESSURE TRANSMITTER
ABSTRACT OF THE DISCLOSURE
An isolator or the like for nuclear power stations
employed to separate two fluids or two pressures or other
sensing instruments from the containment or elsewhere.

Claims

WHAT IS CLAIMED IS:
1. A sensitive fluid responsive device, said device
comprising: a housing having a central transverse
partition and first and second enclosing side walls, said
housing having an opening thereinto on each side of said
partition; first and second bellows each having a fixed end
sealed around respective opposite sides of said partition,
said first and second bellows having first and second
closed movable ends with first and second respective
recesses, said recesses extending inwardly toward said
partition; first and second bodies; first means; second
means, said first means and said second means fixing said
first and second bodies relative to said housing, said
bodies being fixed relative to said housing in positions
and having first and second respective portions nesting in
said first and second recesses, respectively, said first
and second bodies' first and second portions filling major
portions of the volumes of the respective first and second
recesses; and incompressible fluid portions inside each of
said bellows filling the same and being in communication
with each other.
2. The invention as defined in claim 1, wherein said
housing has a construction forming first and second
chambers outside said recesses and outside said first and
second bellows, respectively, said first and second bodies
having third and forth portions, respectively, occupying
substantially all of the space within said first and second
chambers, respectively.
3. The invention as defined in claim 2, wherein said
housing includes first and second end walls partially
defining said first and second chambers, respectively, said
first and second means fixing said third and forth portions
of said first and second bodies, respectively, to said
first and second housing end walls, respectively.
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4. The invention as defined in claim 1, wherein said
housing includes first and second end walls partially
defining said first and second chambers, respectively, said
first and second means fixing said third and forth portions
of said first and second bodies, respectively, to said
first and second housing end walls, respectively.
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Description

V. N. Lawford - 13
~i85~Z
PRES~URE TRANSMITTER
BACKGROUND OF THE INVENTION
.
This invention relates to means for transmitting
pressures through two or more separated fluids, and more
particularly to an instrument akin to a differential
pressure unit (DPU).
PRIOR ART STATEMENT
A typical DPU of the prior art is shown in U.S.
Patent No. 2,6~4,749 issued January 5, 1954.
Devices to isolate, for reasons of temperature,
radioactivity or for other reasons, relative to the
operation of a nuclear power station are known from U.S.
Patent No. 3,696,659 issued October 10, 1972, and U.S.
Patent No. 3,956,937 issued May 18, 1976.
In the prior art, excessive liquids expand
excessively when heated in such devices. This causes
excessive elongation of the sensor bellows.
SUMMARY OF THE INVENTION
:
In accordance with the device of the present
invention, the above-described and other disadvantages of
the prior art are overcome by providing a sensitive fluid
responsive device, said device comprising: a housing having
a central transverse partition and first and second
enclosing side walls, said housing having an opening
thereinto on each side of said partition; first and second
bellows each having a fixed end sealed around respective

~168SS~ v. N. Law~ord - 13
opposite sides of said partition, said first and second
bellows having first and second closed movable ends witn
first and second respective recesses, said recesses
extending inwardly toward said partition; first and second
bodies; first means; second means, said first means and said
second means fixing said first and second bodies relative to
said housing, said bodies being fixed relative to said
housing in positions and having ~irst and second respective
portions nesting in said fiest an~ second recesses,
respectively, said first and second bodies' first and second
portions filling major portions of the volumes of the
respective first and second recesses; and incompressible
fluid portions inside each of said bellows filling the same
and being in communication with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which illustrate an
exemplary embodiment of the present invention:
Fig. 1 is a longitudinal sectional view of an
isolator constructed in accordance with the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In Fig. 1, an isolator 10 similar to a differential
pressure unit (DPU) is shown. Isolator 10 has a housing 11
including members 12 and 13 having cylindrical external and
internal surfaces 14, 15 and 16, 17, respectively.
Surfaces 15 and 17 partially enclose essentially
fluid tight chambers 18 and 19, respectively.
Inlet and/or outlet openings into and/or out of
chamber 18 are provided at 20 and 21.
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~6~
Openings into and/or out of chamber 19 are provided at
22 and 23.
Everything outside the mathemetical surface passing
through surfaces 15 and 17 may be conventional.
Everything inside the same said mathematical surface
may be conventional except end walls 24 and 25 of housing
castings 26 and 27, respectively, plugs 28 and 29, threaded
pins 30 and 31, and welds 32 and 33 connecting pins 30 and
31 to end walls 24 and 25, respectively.
Parts 34, 35, 36 and 37 form a partition with chambers
18 and 19 having fluid tight seals.
Bellows 38 and 39 each are provided with an
incompressible fluid filling the same, wherein the fluid in
one is in communication with-that in the other.
Conventional overrange valves are provided at 40 and 41
having O-rings at 42 and 43, respectively. FOJ: example,
see O-rings 3i and 32 in U.S. Patent No. 2,632,474 issued
March 24, 1953, and overrange valve seats 29 and 30,
respectively.
Recessed ends 44 and 45 of bellows 38 and 39,
respectively, are fixed relative to each other by stem 46
as is conventional.
Bores 47 and 4~ are large enough- ta permi~-the
incompressible fluid to flow from inside one bellows to
inside the other or vice versa. For the remaining
structures see the last mentioned patent.
OPERATION
When the pressure in chamber 18 is higher than that in
chamber 19, bellows 38 tends to collapse and bellows 39
tends to expand. The contrary is likewise tr~le.
If the maximum differential pressure is very low, the
bellows spring force constants may be negligible. If not,
the spring forces may or may not stop bellows movements
before an overrange valve closes.
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3~16~5~
Although the differential pressure may be indicated, it
need not be indicated.
A switch for an alarm may also be provided, but may be
unnecessary.
S One important purpose of the present invention is to
cause the pressure in chamber 18 to operate something in
communication with chamber 19 or vice versa without the
fluids in chambers 18 or l9 mixing.
See the first two patents cited herein for further
utility.