A modulating valve device, operated by fluid pressure in fluid motors to control work pressure, is described

Jacob, D. S.

English

NASA Technical Reports Server

United States Patent t 191 [ I 1 1  4,033,479 
Fletcher et al. [45] July 5, 1977 
PRESSURE MODULATING VALVE 
Inventors: James C. Fletcher, Administrator of 
the National Aeronautics and Space 
Administration, with respect to an 
invention of; David S. Jacob, Irvine, 
Cali. 
Filed: July 26, 1976 
Appl. No.: 708,795 
U.S. CI. ................................... 222/61; 222/95; 
Int. C1.* ....................... B67D 5/28; B67D 5/14 
Field of Search ............. 222/52, 61, 95, 386.5, 
128/214 F; 128/DIG. 12 
222/389; 128/214 F, DIG. 12 
[561 References Cited 
UNITED STATES PATENTS 
3,561,644 1011967 Works ................................. 222195 
3,827,599 811974 Rastogi ................................ 222152 
Primary Examiner-Stanley H. Tollberg 
Assistant Examiner-Hadd S. Lane 
Attorney, Agent, or Firm-Russell E. Schlorff; Marvin 
F. Matthews; John R. Manning 
[571 ABSTRACT 
Operating fluid pressure is supplied to a fluid motor 
past a modulating operating fluid pressure and a work 
pressure so as to control the work pressure. 
11 Claims, 2 Drawing Figures 
9 
https://ntrs.nasa.gov/search.jsp?R=19770021543 2020-03-20T07:26:20+00:00Z
U.S. Patent 
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July5, 1977 4,033,479 
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4,03 3,479 
1 
PRESSURE MODULATING VALVE 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to provisions of Section 305 of the National Aero- 
nautics and Space Act of 1958, Public Law 85-568 (72 
stat. 435; 45 U.S.C. 2457). 
BACKGROUND OF THE INVENTION 
Prior art devices for expelling fluids from flexible 
bag-like containers, for instance, in zero-gravity envi- 
ronment, as in space travel, have resulted in a problem 
due to the steady decrease in flow rate of the expelled 
fluid. An example of such a system is an apparatus for 
administering intravenous solutions, as may be re- 
quired in future space travel. In ground-based facilities, 
reasonably accurate flow may be maintained by means 
of a gravity induced head pressure. However, where 
pressure plates or other squeezing means must be uti- 
lized to maintain the fluid flow from a container bag, 
due to the compliant nature of the bag, the surface area 
against which the external squeezing pressure is applied 
increases as the bag empties. Thus, a constant squeez- 
ing force will result in decreasing internal pressure in 
the container bag and resultant decreasing flow rate. 
Accordingly, the main object of the present invention 
is to provide a novel pressure modulating valve which 
maintains a constant internal pressure in the container 
with a resultant constant flow rate. 
SUMMARY OF THE INVENTION 
In accordance with one embodiment of the present 
invention, one or more bag-like containers are 
DETAIL DESCRIPTION OF THE DRAWING 
The embodiment shown comprises a rectangular 
hollow frame having end members 5 and 6 and top and 
5 bottom members 7 and 8. Received in one portion of 
the frame is the container bag 9 having an outlet fitting 
10 in the peripheral seam 12, to which a discharge tube 
may be connected. In the opposite portion of the frame 
there is placed the bellows 13 secured at one end to 
10 frame member 5 and at the other to a movable wall or 
plate 14 interposed between the actuating bellows and 
the container bag. A tube 15 connects a constant pres- 
sure source of pneumatic fluid through frame member 
5 with pressure chamber 19, as will be described. 
If desired, two or more of the containers 9 may be 
mounted in side by side chambers on frame member 6 
and equipped with suitable piping and valves for joint 
or sequential operation. Wall 6 may be formed in part 
of transparent solid material so that proper loading of 
20 the bags into the chambers may be verified visually. 
Design of the container portion of the apparatus, in the 
exemplary embodiment, was such that a complete tub- 
ing set could be laid intc, the unit without violating its 
sterility. Other values and gauges may be provided 
Mounted on movable wall 14 (FIG. 2) is the novel 
modulator valve including a housing 18 formed as a 
part of plate 14 and with a centrally projecting boss 30, 
both hollowed to form the stepped chamber 19, 20. 
30 Traversing this chamber and defining and segregating 
pressure chamber 19 is the diaphragm 21 peripherally 
secured in place by a clamping ring 33 and provided 
with central pressure plates 22 and 23. Projecting left- 
wardly from plate 23 is a pin or plunger 24, the left 
35 hand end of which impinges on a sub-plate or disc 25 
which is movably secured at its periphery to movable 
15 
25 where needed. 
wall by a ring 32. Sub-plate or disc 25, in normal use, 
walls, one of which is actuated by an expansible-cham- bag 9, SO as to reflect container pressure in opposition bertYPe Pneumatic motors such as a 40 to the force exerted by the actuating pressure on dia- 
able wall carries a chambered valve housing which is phragm 21. Plate 25 and plunger 24 act as a self-align- 
traversed by a diaphragm to form on one side thereof a ing “ball and socket” joint to assure that bag 9 is in 
pressure chamber communicating with the Supply pres- contact with plate 25 over the entire area of the plate 
sure. On the other side of the diaphragm, there is a regardless of the manner the bag is inserted in the 
sensing plate or disc which reacts against the container 45 frame. 
pressure and is centrally coupled to the diaphragm. Projecting rightwardly from the other diaphragm 
Extending from the diaphragm oppositely from the pressure plate 22 is a needle valve 28 having a tapered 
sensing plate is a needle valve which controls a valve end for cooperating with the valve-seat-port 29 in hol- 
seat-port and allows the supply pressure in the pressure low boss 30 Projecting from housing 18. An orifice 31 
chamber to communicate with the actuating pressure 50 in the end wall of housing 18 exposes pressure chamber 
in the pneumatic motor. Thus, the diaphragm and nee- 19 and the right hand side of the diaphragm to the 
dle valve are balanced between the force imparted by constant SUPPlY pressure provided through tubing 15. 
OPERATION the supply pressure on the diaphragm and the reacting 
force on the sensing plate imparted by the internal 
In operation, with bellows 13 relaxed, a charged pressure of the bag-like container. As the container container 9 is placed between frame end member 6 and 
empties, the valve operates in such a way so as to pro- movable wall 14. Then, with all plumbing properly 
vide a substantially uniform hydrostatic pressure in the connected and adjusted, activating pneumatic gas is 
BRIEF DESCRIPTION OF THE DRAWING 60 19. When the force exerted by the pneumatic fluid 
through diaphragm 21 exceeds the counteracting con- 
tainer pressure, needle valve 28 opens, admitting pneu- In the accompanying drawing, 
FIG. 1 is an elevation of a fluid discharge device matic fluid to the interior of the bellows and ultimately 
embodying the invention, a Part being broken away and causing expansion of the bellows to squeeze the con- 
the flexible container being shown in different operat- 65 tainer bag. With the container fluid discharge valve 
ing positions. open, this fluid is expelled from the bag. The dimension 
lines marked “Contact Area 1” indicates the area of 
the working parts. the container walls initially engaged by squeezing walls 
mounted in position to be squeezed between a Pair of bears against a portion of the side surface of container 
The 
55 
container and resultant uniform discharge supplied through tube or pipe 15 to pressure chamber 
FIG. 2 is a schematic longitudinal section illustrating 
2 
4,033,479 
A 
J 
6 and 14 in “Position 1.” As fluid expulsion continues, 
movable wall 14 reaches the dot-and-dash line “Posi- 
tion 2,” while the container assumes the flattened, 
laterally expanded shape indicated by dot-and-dash 
lines 9a. The dimension line marked “Contact Area 2” 
indicates the increased areas of engagement between 
the pressure walls 6 and 14 and the container surfaces. 
Accordingly, the squeezing force applied by the bel- 
lows is progressively more diffused and the internal 
container pressure, per advance increment of the mov- 
able wall, is reduced. 
To compensate for the resultant reduction in hydro- 
static pressure in the container and consequent reduc- 
tion in discharge rate, such pressure reduction results 
in a leftward shifting of inner, movable wall portion 25 
and the diaphragm relative to movable wall 14 and 
opening of needle valve 28 to admit additional actuat- 
ing pressure gas into the bellows through tube 15 and 
port 29. This, in turn, will provide the necessary com- 
pensating increase in squeezing force on the container 
to maintain the discharge from the container at a uni- 
form rate. When the uniform discharge rate is restored, 
needle valve 28 will close or assume an intermediate 
position where leakage through port 29 will be just 
sufficient to continuously balance the pressure decay 
tendency as mentioned above, during emptying of the 
bag. 
With the use of the invention as described, it was 
found possible to produce a constant flow within k 8 %  
at lower flow rates, and 6% at higher flow rates. These 
flow rates are substantially better than has been ob- 
tained with conventional fluid infusion system of the 
same general type under zero-gravity conditions. The 
system is especially advantageous for space flights be- 
cause of the absence of any electrical power feature, 
complete portability, light weight and small volume, 
whiIe being rugged and reliable. 
Other fluid pressure to linear force conversion motor 
devices may be utilized, such as cylinders, bladders, 
and diaphragms. Moreover, the modulating valve con- 
cept may be used in other work applications, as for 
compressing any visco-elastic material or object where 
constant internal pressure is desired. One such applica- 
tion might be compression molding of plastics. As the 
molding material is compressed and spreads within the 
mold cavity, the area of reactive contact in the molds 
increases so that the rate of pressure increase within 
the visco-elastic material decreases per unit advance of 
the compressor ram at constant force. If, however, the 
pneumatic or hydraulic ram force is increased in pro- 
portion to the spread of the contact of the molding 
material within the mold, as by application of the pre- 
sent invention, the density of the molded part may be 
maintained constant throughout. 
The invention may be modified in these and other 
respects as will occur to those skilled in the art and the 
exclusive use of all modifications as come within the 
scope of the appended claims is contemplated. 
I claim: 
1. A modulating valve device comprising first and 
second relatively movable wall means, respectively for 
transmitting force applied by a fluid motor to a work 
instrumentality and for sensing the reactive pressure of 
the work, a valve housing having a movable wall and 
forming a pressure chamber, first and second ports in 
the wall of said chamber, respectively, for admitting 
actuating fluid to said chamber and directing said fluid 
to the fluid motor, a valve actuable by said movable 
wall and cooperable with said second port, and a con- 
5 
10 
15 
20 
25 
30 
35 
40 
45 
4 
nection between said sensing wall means and said mov- 
able wall acting on said movable wall in opposition to 
the effect of the actuating fluid thereon. 
2. A modulating valve device as described in claim 1 
in which said movable waIl is a flexible diaphragm 
traversing said chamber and said valve is secured cen- 
trally thereto. 
3. A modulating valve device as described in claim 1 
in which said first and second relatively movable wall 
means form a continuous wall, said first wall means 
being adapted for connection to a fluid motor and said 
second wall means being movably mounted in a central 
aperture in first wall means. 
4. A modulating valve as described in claim 3 in 
which said movable wall is a diaphragm traversing said 
chamber to form a pressure chamber on one side 
thereof and said second wall means is actuably con- 
nected to the other side of said diaphragm. 
5. A modulating valve device as described in claim 4 
in which said fluid motor is a bellows peripherally at- 
tached to said first wall means. 
6. The combination with a compressible means of a 
type subject to pressure variation when compressed 
and motor means for applying compressive force to 
said compressible means, of modulating means respon- 
sive to the reactive pressure of said compressible means 
for adjusting the compressive force applied by said 
motor means in proportion to the pressure change in 
said compressible means. 
7. The combination described in claim 6 in which 
said motor means is fluid pressure actuated and further 
including a source of pressured actuating fluid, said 
modulating means comprising a valve controlling the 
pressure applied to said motor means for varying the 
compressive force applied by said motor means. 
8. The combination described in claim 7 in which 
said compressible means comprises a bag-like fluid 
container and said motor means includes a movable 
wall bearing against an increasing area of the container 
wall as the container empties during squeezing thereof. 
9. The combination described in claim 8 further in- 
cluding a hollow housing carried by said movable wall, 
a diaphragm traversing the interior of said housing and 
forming therewith a pressure chamber on one side of 
said diaphragm, first and second port means connect- 
ing said pressure chamber, respectively to said source 
of actuating fluid and said motor means, the portion of 
said movable wall traversing said housing interior and 
engageable with said bag-like container being trans- 
versely movable relative to adjacent parts of said mov- 
50 able wall, and a connection between said latter men- 
tioned movable wall portion and said diaphragm, said 
modulating means comprising a valve actuable by said 
diaphragm and cooperable with said second port means 
to vary the pressure applied by said motor means. 
10. The combination described in claim 9 in which 
said motor means is of the expansible chamber type 
with an actuating part connected to said movable wall. 
11. The combination described in claim 9 further 
including a rigid frame having opposed walls, said 
60 motor means, including said movable wall, being re- 
ceived in one portion of said frame adjacent one of said 
opposed walls and said bag-like container being re- 
ceived in another portion of said frame between said 
movable wall and the other opposed wall, said con- 
65 tainer being replaceable and there being an opening in 
the side of said latter frame portion for introduction 
and removal of charged and exhausted containers. 
5 5  
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Pressure modulating valve

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