An apparatus for degassing a liquid comprises a containment vessel a liquid pump and a header assembly (12) within the containment vessel in a volume above the reservoir of the liquid. The pump draws from this reservoir and outputs to the header assembly, the latter being constructed to return the liquid to the reservoir in the form of a number of stacked, vertically spaced, concentric, conical cascades via orifices. A vacuum source provides a partial vacuum in the containment vessel to enhance the degassing process

Yamauchi, S. T.

English

NASA Technical Reports Server

United States Patent [19] [111 4,392,874 
Yamauchi [45] Jul. 12, 1983 
[54] DEGASSIFYING AND MIXING APPARATUS 
[75] Inventor: Samuel T. Yamauchi, Fountain 
Valley, Calif. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
FOR LIQUIDS 
[21] Appl. No.: 325,082 
[22] Filed: Nov. 25, 1981 
[51] Int. ( 3 . 3  .............................................. BOlD 19/00 
[52] U.S. CI .  ......................................... 55/194; 55/202 
[58] Field of Search ................. 55/39, 41, 52, 55, 182, 
55/189-194, 201, 202 
[561 References Cited 
U.S. PATENT DOCUMENTS 
1,511,876 10/1924 Ehrhart ............................. 55/194 X 
1,895,983 1/1933 Emanueli .............................. 55/194 
2,060,242 11/1936 Pulley ................................... 55/190 
2,285,973 6/1942 Hopkins ............................ 55/191 X 
2,540,390 2/1951 Gorgerat et al. ..................... 55/192 
2,507,797 5/1950 Martin .............................. 55/190 X 
2,668,598 2/1954 Seed ...................................... 55/192 
4,062,661 12/1977 Wiemer et al. ....................... 55/190 
FOREIGN PATENT DOCUMENTS 
1034675 6/1966 United Kingdom .................. 55/194 
Primary Examiner-Robert H. Spitzer 
Attorney, Agent, or Firm-Russell E. Schlorff; John R. 
Manning; Marvin F. Matthews 
[571 ABSTRACT 
A liquid degassifier including a containment vessel (lo), 
a liquid pump (16) and a header assembly (12) within the 
containment vessel (10) in a volume above the reservoir 
(lla) of liquid therein. The pump (16) draws from this 
reservoir and outputs to the header assembly, the latter 
being constructed to return the liquid to the reservoir in 
the form of a stacked plurality of vertically spaced, 
concentric, conical cascades (134 14a and 15a) via 
orifices (13, 14, and 15). 
A vacuum source (34) provides, a partial vacuum in the 
containment vessel (10) to enhance the degassing pro- 
cess. 
6 Claims, 2 Drawing Figures 
t 
I '7, 
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U.S. Patent Jui. 12, 1983 Sheet 1 of 2 4,392,874 
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Sheet 2 of 2 4,3 92,874 
4,392,874 
1 
processed as it passes over surfaces in a partially evacu- 
ated vessel. 
In US. Pat. No. 1,836,338 (Rodman et al.), spraying 
of a liquid vertically upward into a partially evacuated 
Causing a liquid (Le., oil) to flow in a thin layer over 
an elongated path at less than atmospheric pressure for 
degassing and water vapor removal appears to be the 
~ E ~ A ~ $ ~ ~ ~ ~ ~  AND ~~~~~~ A ~ ~ A ~ A ~ $  FOR 
LIQUIDS 
ORIGIN OF THE INVENTION 5 vessel is employed for degassing. 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
(72 STAT. 435; U.S.C. 2457). 
of the pat. No. 3,789,579 (El Hindi). Aeronautics and Space Act of 1958, Public Law 85-568 The special problem of degassification of a high vis- 
cosity liquid (e.g., viscose) in a vacuum tank as the 
liquid passes over baffles intended to cause a filming 
action, is described in Elliott et al. U.S. Bat. No. 
3,368,330, 
TECHNICAL FIELD 
The invention relates generally to liquid degassifiers 
adapted for liquid and more specifically to 15 U.S. pat. No. 3,325,974 (Griffin), provides the basic 
function of drilling mud degassing at sub-atmospheric degassifiers for potable water which vacuum 
pressure by passing the mud over baffle surfaces as in degassification. 
Burnham patents aforementioned. 
frequently encountered. Other fields of utilization in- 2o soft drinks, etc., to increase affinity for desolving Co2 
clude hydraulic systems for aircraft and heavy machin- for carbonation. A series of 6cpans,, provides for break- 
ery and in the field of heat transfer devices, where maxi- ing up the liquid in the vacuum chamber. 
U.S. Pat. No. 1,457,153 (Elliott), degasses steam mum heat transfer is required. 
BACKGROUNDART boiler feed water in a vacuum vessel relying on the 
25 “violent ebullition of flashing action” during injection 
The need for degassification of liquids is encountered into the vessel. 
in the above-mentioned applications and others which and cans- 
arts. An application for which the present invention is of spray for increasing the liquid degassing 
for use on a spacecraft. guiding core, respectively. 
Prior art liquid degassifiers all provide some form of disclosed in U.S. 
liquid particle or film break-up to increase liquid surface Pat. N ~ ~ .  3,831,352 (parcels) and 3,358,425 and 
subject to degassification. The prior art apparatus for 3,481,113, parcels having a break-up impeller and all 
the accomplishment of that filming or particlizing has 35 comprising baffle structures in a vacuum vessel. 
usually been bulky because oftray and baffle use. Also, Canadian Pat. No. 653,008 (Anderson) undertakes to 
Such Prior art apparatus occupies a large fraction ofthe constrain the filming aperture of the liquid between 
container tank volume. concentric conical surfaces, but thereafter permits liq- 
Finally, motor drives have been used in Some Prior uid flow over one conical surface such that the liquid is 
art devices (in addition to the usual pump). 40 exposed to the vacuum environment on one surface 
The general concept of degassing a liquid or liquid only. 
mixture in a partial vacuum is disclosed in U.S. Pat. US. Pat. No. 2,979,156 (Sebald), appears to employ 
Nos. 3,517,487 and 3,555,819 (Burnham) as well as in liquid spray degassing in a vacuum vessel with particu- 
U.S. Pat. No. 2,714,938 (Smith) and various other refer- lar attention to pressure equalization to minimize the 
ences, and can be considered known per se. 
U.S. Pat. No. 4,007,022, (Schleicher et al.) deaerates a Most of the foregoing prior art references include 
dispersion of PVC in water while Burnham is con- flow-path baffle or tray arrangements for increasing the 
cerned with deaeration of drilling mud, both more vis- liquid or mixture exposed surface in a vacuum vessel, 
cous ; ixtures, than water or the like as SO advanta- except where conventional spray apparatus is em- 
geously handled by the invention. 50 ployed. The prior art does not appear to include the 
US. Pat. No. 2,071,393 (Doherty) concerns deaera- concept of cascading the liquid in thim films within a 
tion of a relatively viscous mixture, to wit: catsup. A vacuum vessel free of any filming baffle or other guid- 
motor drive appears to provide a type of centrifuging ing structure. 
action by means of a driven beater arrangement. US. It will be seen that truly thin film liquid formations 
Pat. No. 2,041,059 (French), applies teachings very 55 for optimum degassing efficiency are not provided in 
similar to those of Smith to the degassing of milk or the prior art. Moreover, wherever a liquid flow over a 
cream during pasteurization. U.S. Pat. Nos. 3,358,425 surface is relied upon to obtain a liquid film, only one 
and 4,210,176 (Rodman et al.) accomplish a very similar surface of the film is exposed to degassification force 
result for oil purification employing rotating disks for (vacuum, for example). 
fluid filming. Liquid sprays do not provide suflticiently high liquid 
U.S. Bat. No. 2,064,650 (Emanueli) degasses liquids, surface exposure for optimum degassification, and 
particularly oil, by spreading the liquid over a filming “mud” or other liquid/solid mixtures are obviously not 
structure by centrifugal force (a motor-driven struc- degassable in analogous structures and by analogous 
ture). methods vis-a-vis, the degassification of water and other 
processing by deaeration to remove odors generated by The manner in which the invention deals with the 
prior ultra-violet irradiation. Vanes for generating a disadvantages and inadequacies of the prior art will be 
deaerating surface are provided, the material being understood as this specification proceeds. 
In the arts relating to spacecraft, the need for degas- 
sing of liquids* such as the potable water is U.S. Pat. No. 1,598,787 (Shield$ degasses water and 
U.S. Pat. N ~ .  2,540,390 ( G ~ ~ ~ ~ ~ ~ ~  et 
Will be recognized by those of skill in the corresponding dian Pat. No. 653,008 (Anderson) are further examples 
especially useful is the degassification of potable water 30 surface, by gravity liquid fall and force nozzle Over a 
Other drilling mud degassers 
45 vacuum pumping effort required. 
60 
U.S. Pat. No. 2,020,250 (Stephens) concerns food 65 liquids of relatively low viscosity. 
3 
DISCLOSURE O F  THE INVENTION 
4,392.874 
The invention provides a unique apparatus which 
breaks the liquid into a plurality on conical, thin-film, 
unguided cascades, both surfaces of which are exposed 
to the degassing environment. That environment is 
preferably a partial vacuum. Normally the stacked coni- 
cd cascades would be pump driven and the degree of 
evacuation of the surrounding space is kept above the 
vapor pressure of the liquid to preclude fluid loss during 
operation. Chilling of the liquid is known to lower 
vapor pressure, of course. 
In general, the thinner a liquid film can be made, the 
larger the degassification (deaeration) rate. The present 
invention greatly improves on prior art devices in that 
regard. The structure of the invention can provide more 
fluid exposure at lower liquid pressure (2.5 to 7.5 psig) 
than any other known commercial device for the pur- 
pose. 
At 8.0 to 18 psig liquid pumping pressure, the deaera- 
tor of the invention doubles its liquid exposure area. 
The circumferential fluid spread prevents local stratifi- 
cation and affords fluid mixing capability both within 
the liquid films as well as by mechanical action as the 
spray strikes the reservoir of liquid in the containment 
vessel. 
The high efficiency of degassification achieved by the 
invention translates into smaller and lighter, as well as 
less expensive equipment. The relatively simple struc- 
ture of the invention will also be appreciated. 
The term degassification is the more general term, 
however the interchangeable term deaeration describes 
the usual process in that it is most often that the gas to 
be removed is air. 
A detailed description of a typical device according 
to the invention follows. 
BRIEF DESCRIPTION O F  DRAWINGS 
FIG. 1 is a mechanical schematic of a typical combi- 
4 
The pump 16 performs the function, entirely conven- 
tional per se, of circulating liquid from the reservoir of 
liquid 11 via pipes of tubes 17 and 18, and vacuum 
source 34 may be a conventional pump or the like. 
Deaeration in the apparatus of FIG. 1 can be re- 
garded as a batch or continuous process, however, fill 
and tap valves have not been shown since these are well 
known per se. 
As previously indicated, the header assembly 12 is a 
10 generally cylindrical body with its axis running verti- 
cally as depicted in FIG. 1. The orifices are essentially 
5 
15 
20 
25 
30 
35 
nation comprising the degassification/mi& of the in- 40 
vention; and 
FIG. 2 is an axially taken cross-section of the header 
assembly of FIG. 1. 
BEST MODE O F  CARRYING OUT THE 
INVENTION 
Referring now to FIG. 1, the overall combination of 
the invention will be seen. Although the advantages of 
the novel filming technique of the invention apply 
whether or not the containment vessel is evacuated, the 50 
combination with vacuum degassification environment 
is much more efficient and will be described in the 
preferred combination. 
In FIG. 1 the storage vessel 10 is a vacuum-tight 
container or tank. Liquid 11 has an arbitrary level l l a  55 
which must always be below the lower extremity of the 
header assembly 12. 
The header assembly 12 is shown having three down- 
ward directed circumferential orifices 13, 14 and 15, 
producing corresponding conical liquid film cascades 60 
13a, 14a and 15a. It is to be understood, however, that 
these three cascades constitute a design decision and 
within the inventive concept, more or fewer orifices 
and corresponding conical liquid film cascades can be 
provided. The resulting degassing rates are roughly 65 
proportional to the number of such cascades (other 
parameters, such as liquid pumping pressure and degree 
of vacuum being the same). 
45 
circular rings projecting as circular bands about the 
circumference of this cylindrical body. Central to the 
header body and extending from input 19 is a passage 
which communicates with the passages leading to the 
orifices. This structure will be more fully understood 
from FIG. 2. 
Referring now to FIG. 2, the orifices 13, 14 and 15 
can be identified. Although FIG. 2 indicates that the 
body of the header assembly is not uniformly cylindri- 
cal, it is spoken of as being generally cylindrical because 
of the cylindrical outer envelope into which it would 
fit. From input 19 the manifold comprises the bore on 
passage 20 having lateral openings 21, 22 and 23 com- 
municating with the annular passages 136, 146 and 156, 
the latter ending in corresponding circumferential ori- 
fices 13,14 and 15. Axially enlarged portions of 136,146 
and 156, comprising 24,25 and 26 respectively, may be 
thought of as acting as part of the manifold or liquid 
plenum. 
The lateral openings 21,22 and 23 will be seen to be 
progressively smaller from top to bottom, this helping 
to provide separation of the conical cascades falling 
through the evacuated volume into the reservoir. 
In one embodiment of the invention, the orifices 21, 
22 and 23 were sized for a specific total system flow rate 
of 3.75 gallons per minute. The flow was divided so that 
more liquid would flow through the top orifices than 
the bottom, providing maximum quantity at the outer 
periphery. The other smaller holes were sized to pro- 
vide enough cascading for filming as well as flow distri- 
bution for mixing of other fluids. Alternatively, all ori- 
fices could be made the same size with adjustments 
being made by controlling the liquid gap. However, the 
arrangement illustrated reduces flow adjustment to a 
minimum. 
The orifices 13, 14 and 15 may be adjustable on pre- 
settable based on the desired cascade film thickness 
emitted. For that purpose, one typical possible adjust- 
ment structure for adjusting the orifice liquid gaps is 
provided by the relative axial positioning of body parts 
27 and 28 (for example) by means of captive adjustment 
nuts such as 30 and 31 engaging a threaded portion of 
the body tube member 33 at 32, for example seal mem- 
bers 29 may be inserted between the body parts and 
their captive nuts for sealing between sprays. Other 
conventional mechanical expedients are, of course, 
available to the skilled artisan for accomplishing the 
same objective. Orifices 13 and 15 can be similarly ad- 
justed by equivalent structure identifiable on FIG. 2. 
Materials and fabrication methods are all entirely 
conventional. Metals and certain well known plastic 
materials can be suitable for the header assembly. The 
same is true of the containment vessel and the other 
elements of FIGS. 1 and 2. 
Where corrosive materials are to be degassed, suit- 
ablv resistant materials must be used. 
4,392,874 
5 6 
Variations and mndifications are obviously possible generally cylindrical body having a generally axial cav- 
as a matter of ordinary skill once the principles of the ity therein, and a liquid passage connecting each of said 
invention are appreciated. Accordingly, it it not in- orifices to said liquid manifold; a second means for 
tended that the scope of the invention should be re- circulating said liquid from said first volume to said 
garded as limited to the specific embodiment shown and 5 header assembly liquid input;, and a third means for 
described. partially evacuating said second volume. 
I claim: 2. Apparatus according to claim 1 in which the liquid 
1. Liquid degassifying apparatus comprising: a vac- passages are progressively smaller from top to bottom. 
uum tight vessel for containment of liquid to be sub- 3. Apparatus according to claim 2 in which the open- 
jected to continuous degassing operations, the level of 10 ing of the orifices are adjustable. 
said liquid within said vessel producing a first liquid 4. Apparatus according to claim 3 in which the cylin- 
volume therein, the remainder of the volume of said drical body has male threads on its outer surface and 
vessel comprising a second volume; a header assembly each orifice is defined by a pair of members having 
withirl said second volume, said header assembly in- female threads engaging with the male threads whereby 
cluding a stacked, spaced plurality of axially narrow 15 the thickness of each orifices may be adjusted. 
orifices, each of said orifices extending generally cir- 5. Apparatus according to claim 4 in which there is a 
cumferentially about the axis of said header assembly to smaller liquid passage below the orifice to form with the 
produce a plurality of cascades of spaced generally lower member of the bottom orifice a further conical 
concentric, conical, liquid films into said first volume spray. 
and means for adjusting the thickness of the liquid films; 20 6. Apparatus according to claim 1 in which the open- 
a first means including a liquid input and manifold for ing of the orifices are adjustable. 
said header assembly, said manifold being formed of a * * * * *  
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Degassifying and mixing apparatus for liquids

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