Gauge for measuring quantity of liquid in spherical tank in reduced gravit

Smith, H. A.

English

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ec. a H. A. SMITH 
SPHERICAL TANK GAUGE 
Filed Aug. 26, 1965 
https://ntrs.nasa.gov/search.jsp?R=19710011532 2020-03-17T02:55:18+00:00Z
9 35 United States Patent Office patented 5, 1967 
1 
3,355,948 
SPHERICAL TANK GAUGE 
Harvey A. Smith, Hampden, Mass., assignor, by mesne 
assignments, to the United States of America as repre- 
sented by the Administrator of the National Aeronautics 
and Space Adminiitration 
Filed Ang. 26, 1965, Ser. No. 482,670 
4 Claims. (Cl. 73-290) 
ABSTRACT OF THE DISCLOSURE 
An apparatus for measuring the quantity of liquid in a 
spherical tank located in a reduced gravity atmosphere 
including a flexible bladder mounted internally across 
the tank, and a retractable measuring stick attached to 
the center of the bladder and extending through an open- 
ing in the tank. Circular rigid hoops are mounted on the 
bladder coaxial with the center line of the tank for stabi- 
lizing the bladder and causing it to remain centered in the 
tank. 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provision of Section 305 of the National Aero- 
nautics and Space Act of 1958, Public Law 85-568 (72 
Stat. 435: USC 2457). 
This invention relates to liquid quantity measuring in- 
struments and particularly to a liquid level gauge for a 
spherical tank which tank is subjected to zero gravity con- 
ditions. 
Due to the advent of outer space exploration the meas- 
urement of liquid in an enclosed container has presented 
problems in view of the fact that the outer space is a 
gravity free environment, In  any such measuring system 
it is necessary for the measuring device to be relatively 
simple, lightweight and be repeatable over a considerable 
time period. 
This invention concerns itself with measuring the 
quantity of liquid contained in a spherical tank, and is 
relatively simple inasmuch as the quantity is measured 
from a position of a bladder. The bladder is preloaded 
with sufficient force to form the bladder and liquid into 
a predictable shape such that under zero gravity condi- 
tions a readout can be cal2brated for various axial blad- 
der locations. Each bladder location has one unique cor- 
responding quantity of liquid. 
One of the problems attendant with the use of an un- 
reinforced bladder ia a zero gravity environment is that 
the bladder near the end of its stroke does not complete- 
ly empty the liquid in the container since the bladder 
tends to bulge inwardly. This problem is overcome by 
attaching circular rigid hoops to the bladder such that 
the bladder touches the bottom of the tank simultaneous- 
ly with the tank emptying completely due to bladder 
shaping by the hoops, These hoops have a dual func- 
tion inasmuch as they tend to stabilize the bladder and 
cause it to remain on the axial center line of the tank. 
It is therefore an object of this invention to provide 
a liquid level indicator adapted to measure the quantity 
of liquid of a spherical tank subjected to a nongravi- 
tational environment. 
A stiII further object of this invention is to provide, 
in a liquid level gauge as described, a flexible bladder 
within a spherical tank and having concentric rigid hoops 
secured to the bladder in order to stabilize the bladder 
and cause it to remain on the axial center line of the 
tank. 
A still further object of this invention is to provide a 
liquid level gauge for a spherical tank as described, 
which aauee is characterized as relativelv simole. ac- 
2 
curate and having good repeatability although subjected 
to a nongravitational environment and also subjected to 
rugged use. 
'Other features and advantages will be apparent from 
the specification and claims and from the accompanying 
drawings which illustrate an embodiment of the inven- 
tion. 
FIGURE 1 is a view partly in schematic and partly 
in section illustrating the spherical tank when it is sub- 
stantially filled with liquid. 
FIGURE 2 is similar to FIGURE 1 only showing the 
tank partially filled. 
FIGURE 3 is substantially identical to FIGURES 1 
and 2 only showing the tank in its empty condition and 
15 also illustrating the combined tension and gauge mecha- 
nism of this invention. 
FIGURE 4 is a partial sectional view of the bladder 
illustrating the attachment of one of the hoops. 
FIGURE 5 is a partial view in elevation indicating the 
2o scale for detecting the level of liquid within the spherical 
chamber. 
Referring now specifically to the details of the figures, 
the spherical tank is shown generally by numeral 10 com- 
prising upper casing member 12 having a radially ex- 
25 tending flange 14 and a lower casing 15 having a radially 
extending flange 16 complementing flange 14. A plurality 
of openings formed in flanges 14 and 16 are adapted to 
receive a suitable attaching mechanism such as a nut 
and bolt assembly generally indicated by numeral 18. 
30 The bladder 20, made from a suitable flexible material 
capable of restraining movement of the liquid but yet 
flexible enough to contour itself to the particular shape 
of the liquid but 'being retained by the hoops to be de- 
scribed hereinbelow, is supported at its outer periphery 
Centrally disposed of the bladder 20 is a flat plate- 
like member 22 suitably secured to the inner surface of 
the bladder and may be retained thereto by any suitable 
means. Extending therefrom is a flexible wire 24 which 
40 in this instance is the coil of the coil spring generally 
indicated by numeral 26, suitably supported to shaft 28, 
more evidenced by viewing FIGURE 3. Judicially se- 
cured to the outer surface of the bladder 20 are hoops 
30 and 32 which are concentrically mounted relative to 
45 the axial axis of the bladder. Thus the hoops 30 and 32 
are coaxially mounted relative to the spring 24. 
As can be viewed from FIGURE 2, showing a partial 
emptying of the spherical container, the hoops 30 and 32 
serve to stabilize the bladder and cause it to remain on 
50 the axial center line of the tank. The concentric hoops 30 
and 32 are supported to the bladder by suitable fabric 
retaining tab members 34 which are either cemented or 
sewn directly to the bladder itself. In the empty position 
it will be appreciated that the force exerted by spring 26 
55 causes the hoops to abut against the inner wall of the 
spherical tank which serves to substantially empty liquid 
out of the tank. Suitable tubing 38 attaching to the spring 
enclosure member 40 serves to fill and empty the tank 
throiigh the aperture 42 formed on the bottom of the 
60 spherical tank 10. Of course, the means for emptying 
and releasing liquid from the tank do not form a part of 
this invention and any departure therefrom would ob- 
viously not detract from the scope of this inventi,on. 
Shown in FIGURE 5 is the end view of the enclosure 
65 member 40 having pointer 46 inscribed on a suitable win- 
dow indicated by numeral 44. The spring 24 may be grad- 
uated according to the displacement thereof so that for 
a particular displacement of the spring there will be a 
oorresponding quantity of liquid in the tank. 
Obviously any method of transducing the displacement 
to indicate the quantity of liquid is deemed to be within 
lo 
35 between the inner surfaces of flanges 16 and 18. 
- ,  the scope of this invention. For example, the displace- - "  
3,355.948 
/ d  3 
ay move a well-kmwn pentiometer wbich, in turn, 
would pmdurze a voltage signal indgcative of the yolume 
of the liquid remaining in the tpnk. 
What has been shown by this invention is a relatively 
simple method which measures the ppsition of q bladder 
which, in turn, indicates the quantity of liquid in a 
d tank. This gauge has been successfully 
wn to be efficacious with good repeatability 
The ipclusion of the wtallic stabilizing 
32 Serve to insure that each bladder location 
ue corresponding quantity of liquid while 
also providing means fm stabilizing the bladder and hold- 
h g  it on the axial ceflter of the tank. 
It is to be understood that the invention is not limited 
embodiment herein illustrated gnd de- 
be used in other ways without departing 
I claim : 
1. Means for measuring the volume of fluid contained 
in a spherically shaped container subjected to a non- 
gravitational environment comprising a flexible circular 
shaped bladder extending laterally internally in the con- 
s peripheral edge fastened to the inner 
er, a plurality of parallel circular rigid 
hoops of varying diameter secured to the face of the 
bladder being in coaxial relation to and spaced longi- 
tudinally Blong the axis of the cpntainer for stabilizing 
and centering the bladder as the volume of fluid in the 
container empties, resilimt means centrally attached to 
from its spirit. 
4 
the bladder and having one end extending through an 
opening formed on the bottom of the container for u g -  
ing the bladder to empty the fluid, a housing supported 
to the container for enclosing said end of said resilient 
5 means, and means for indicating the relative height of 
the bladder whereby the height of the bladder is indi- 
cative of the volyme of fluid in the container. 
2. Means as defined ip claim 1 wherein said resilient 
aim 2 n said 
lo means includes a win said h mount 
graduated indicia formed on said coil spring 
dicia is indicative of the height of said bladder. 
4. Means as defined in claim 1 wherein one face of said 
15 bladder is in intimate contact with the fluid in the con- 
tainer and the hoops are mounted Qn the oppssite face 
of said bladder. 
References Cited 
UNITED. STATES PATENTS 
2o 2,637,111 5/1953 McDuff _ _ _ _ _ _ _ _ _  73-321 XR 
3,044,663 711962 Norton et al. _ _ _ _ _  73-290 XR 
3,180,146 4/1965 Hassack _ _ _ _ _ _ _ _ _ _ _ _ _  73-304 
3,298,466 1/1967 Ayers et al. -_______ 92-5 XR 
25 LOUIS R. PRINCE, Primary Examiner. 
DAVID SCHONBERG, Examiner. 
W. HENRY, Assistant Exmiller.  


Spherical tank gauge Patent

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