When liquid tank is full, baffle is held up against a stop on top of shaft to prevent restriction of flow from outlet. As tank is being emptied, baffle, floating on top of liquid surface, descends with liquid level toward outlet until it reaches its bottom stop. Baffle prevents gas pull-through until practically all liquid is emptied from tank

Howard, F. S.

English

A floating baffle is described which rides up and down on a vertical shaft over a drain in a tank as the liquid level within the tank varies. When the baffle is in the raised position, the liquid is allowed to flow out of the drain at an unrestricted rate. When the baffle is in the lowered position, pull-through of air or gas that is above the liquid is presented, which would interfere and reduce the flow of liquid from the tank

NASA Technical Reports Server

I I ««• * r • f •••
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON, D.C. 20546
FLOATING BAFFLE TO
LIQUID T R A N S F E RI H f K U V t Drrxv. j . twv-* ~- WUU-LW ,scrT n o T
REPLY TO ^JPBOH T A N K S Patent ( N A S A ) 5 P CSCL 131
ATTN OF: GP,
N73-26472
Unclas
00/15 06472
TOs KSI/Scientif ic & Technical Inforra&tion Division
Attentions Miss Winnie Me Morgan
FROM? GP/Office of Assistant General Counsel for
patent Matters
SUBJECT* Announcement of NASA-Owned U.S0 Patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSIe the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided?
U0Se patent NO.
Government or
Corporate Employee
Supplementary Corporate
Source (if applicable)
NASA patent case No.
. -234.
NOTE - If this patent covers an invention made by a corporate
employee of a NASA Contractor, the following is applicable:
Yes
 / / No />^ /
Pursuant to Section 305(a) of the National Aeronautics and
Space Act, the name of the Administrator of NASA appears on
the first page of the patent; however, the name of the actual
inventor (author) appears at the heading of column NoD 1 of
the Specification, following the words *. „ , with respect to
an invention of
 0 » ."
Elizabeth A. Carter
Enclosure
Copy of Patent cited
NASA-HQ
https://ntrs.nasa.gov/search.jsp?R=19730017745 2020-03-17T08:33:06+00:00Z
United States Patent
Howard
mi 3,736,956
[45] June 5,1973
[ 54 ] FLOATING BAFFLE TO IMPROVE
EFFICIENCY OF LIQUID TRANSFER
FROM TANKS
[75] Inventor: Frank S. Howard, Indian Harbor
Beach, Fla.
(73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration, Washington, D.C.
[22] Filed: Sept. 16, 1971
[21] Appl. No.: 181,023
[52] U.S. Cl 137/582, 137/397
[51] Int. Cl F16k 21/14, F16k 31/18
[58] Field of Search 137/582,578,397,
137/585, 586, 204, 202, 396, 398
[56] References Cited
UNITED STATES PATENTS
1,669,271 5/1928 Webb 137/397 X
2,904,062 9/1959 Techier 137/397 X
1,096,788 5/1914 Madden 137/397 X
1,065,899 6/1913 Guyton et al 137/397
2,882,928 4/1959 Cogliati 137/578
3,426,791 2/1969 Nelson 137/582
Primary Examiner— Samuel Scott
Assistant Examiner—Ira S. Lazarus
Attorney—James O. Harrell and John R. Manning
[57] ABSTRACT
A floating baffle which rides up and down on a verti-
cal shaft over a drain in a tank as the liquid level
within the tank varies. When the baffle is in the raised
position the liquid is allowed to flow out of the drain
at an unrestricted rate, whereas, when the baffle is in
the lowered position such prevents pull-through of air
or gas that is above the liquid, which would interfere
and reduce the flow of liquid from the tank.
5 Claims, 8 Drawing Figures
20
Patented June 5, 1973 3,736,956
2 Sheets-Sheet 1
10
.22
28 ,30 20
10
.6.
INVENTOR.FRANK: s. HOWARD
BY O^u .^
ATTORNEY
Patented June 5, 1973 3,736,956
2 Sheets-Sheet 2
24-
.22
•20
10
INVENTOR.
FRANK S. HOWARD
BY
ATTORNEY
3,736,956
1 2
FLOATING BAFFLE TO IMPROVE EFFICIENCY liquid which minimizes pump cavitation wherein a
OF LIQUID TRANSFER FROM TANKS pump is utilized for draining liquid from the tank.
This invention described herein was made by an em- Other objects and advantages of this invention will
ployee of the United States Government, and may be become more apparent from a reading of the following
manufactured and used by or for the Government for 5 detailed description and appended claims taken in con-
Governmental purposes without the payment of any junction with the accompanying drawings wherein:
royalties thereon or therefor. FIGS. 1 through 3 illustrate diagrammatically the
This invention relates to a floating baffle, and more draining of a tank wherein pull through occurs,
particularly to a floating baffle which is carried within FIG. 4 is a fragmentary perspective view illustrating
a tank for preventing pull-through of air from above the 10 a baffling apparatus mounted in a tank, with parts re-
liquid as the tank is drained. moved for the purpose of clarity, provided for minimiz-
One of the problems encountered in draining large ing pull-through,
tanks such as tankers that transport liquid nitrogen, FIG. 5 is a diagrammatic view illustrating the baffling
gasoline, etc., is that when the level of the liquid within apparatus of FIG. 4 in the raised position,
the tank drops below a predetermined level, the air 15 FIG. 6 is a diagrammatic view of the baffling appara-
above the liquid pulls through the drain, reducing the tus constructed in accordance with the present inven-
rate of flow of liquid through the drain. In some in- tion in an intermediate position,
stances the gurgling sound of the pull-through process FIG. 7 is a fragmentary perspective view illustrating
has made personnel draining the tank to believe the a modified form of the invention wherein a baffle is car-
tank to be empty when it is not. This causes additional 20 ried directly over the drain outlet provided in a tank for
transportation costs, plus additional operational man minimizing pull-through, and
hours to empty tanks. The phenomena of pull-through FIG. 8 is a fragmentary perspective view illustrating
is particularly prevalent in tanks which are pressurized still another modified form of the invention,
in order to speed up the rate of flow of the liquid out Referring in more detail to the drawings, FIGS. 1
of the drain. It is possible to place a fixed baffle directly 25 through 3 show the sequence of pull-through of gas as
over the drain for preventing pull-through, but such has liquid is being drained from a tank. The tank is shown
the adverse effect of restricting the flow through the diagrammatically and is identified by the reference
drain when the liquid level within the tank is high. character 10 having a drain outlet 12 located in the
In accordance with the present invention, it has been bottom thereof. This tank could be any tank that con-
found that difficulties encountered in draining tanks 30 tains a liquid and in one particular instance, may be a
may be overcome by providing a novel baffling appara- tanker pulled behind a vehicle, such as for transporting
tus. This apparatus for minimizing pull-through of gas gasoline or liquid nitrogen. Referring to FIG. 1, the liq-
disposed above liquid in a tank when draining the liquid uid is shown at a level above the critical point where
through an outlet provided in the bottom of the tank pull-through takes place and the tank is draining at its
includes the following basic parts: (1) A vertical sup- 35 maximum rate.
port means carried adjacent the outlet, (2) a baffle, (3) In FIG. 2 the level of the liquid has dropper wherein
means for supporting the baffle on the vertical support pull-through is about to begin and a concave dip, such
means for vertical movement responsive to variations as identified by the reference character 16, is beginning
in the liquid level in the tank, (4) the baffle being sup- to form.
ported directly above the outlet and being buoyant so 40 As the level of the liquid drops to the depth shown in
as to float on the liquid for preventing pull-through of FIG. 3 the gas above the liquid in the tank mixes with
gas disposed above the liquid in the tank while draining the liquid 14 at the outlet and reduces the speed of the
the tank, and (S) means for limiting the downward liquid passing through the outlet 12 by restricting the
movement of the baffle so that when the liquid level effective size of the passage in the outlet through which
drops below a predetermined level the baffle is held a liquid is flowing. In some instances the pull-through
predetermined distance above the outlet for allowing process illustrated in FIG. 3 produces a gurgling sound
the remaining portion of the liquid in the tank to flow which has made personnel draining the tank believe the
under the baffle through the outlet to completely drain tank to be empty when it is not. This causes additional
the tank. transportation costs, plus additional operational man
Accordingly, it is an important object of the present hours to empty the tank.
invention to provide an apparatus for improving the ef- FIG. 4 illustrates a tank, only the lower portion of
ficiency of liquid transfer from tanks. such being shown, being adapted with a buoyant baffle.
Another important object of the present invention is The baffling apparatus includes a vertical plate 18
to provide a floating baffle for a tank which aids in .. which is positioned directly over the outlet 12 of the
draining liquid from the tank. tank for limiting the downward movement of the float-
Another important object of the present invention is ing baffle 20. A vertical shaft 22 extends upwardly from
to provide a floating baffle for a tank which is posi- the vertical plate 18 and may be secured thereto by any
tioned over the drain in the tank so as to prevent pull- suitable means, such as welding. Adjacent the top of
through of gas from the tank while the tank is being ,Q the shaft 22 is an outwardly extending flange 24 which
drained. acts as a stop for limiting the upward movement of the
Another important object of the present invention is floating baffle 20.
to provide a floating baffle for a tank which rises and The baffle 20 may take several different forms as
falls with the liquid level to minimize the pull through long as such is buoyant and in the embodiment illus-
of gas in the tank through the drain associated with the
 65 trated in FIG. 4 such takes the form of a cylindrical disc
tank. 26 which has a hole located in the center thereof
Still another important object of the present inven- through which a sleeve 28 passes. The disc 26 is at-
tion is to provide a floating baffle for a tank containing tached to the sleeve 28 by any suitable means, such as
3,736,956
welding. The sleeve 28 in turn, has a bore extending
longitudinally therethrough, through which the shaft 22
passes. Such is loosely fitting so as to allow the baffle
20 to rise up and down on the shaft 22 as the liquid
level within the tank 10 varies. A pair of cylindrical
float tanks 30 are mounted on the disc 26 on opposite
sides of the vertical shaft for making the baffle buoyant.
These float tanks may take the form of sealed contain-
ers or may be constructed of any suitable buoyant ma-
terial.
Referring to FIG. 5, when the liquid level in the tank
10 is above the top of shaft 22 the baffle rises to its up-
permost position, such as shown in FIG. 5, wherein
such engages the stop 24. When the baffle is in this po-
float comprises a cylindrical can 50, which has a disc
shaped baffle 52 secured thereto by any suitable
means, such as welding, which is carried in alignment
with the outlet 12. The float engaging the horizontal
upper flange 40 limits the upward movement of the baf-
fle while the adjustable nut 48 limits the downward
movement of the baffle.
While a preferred embodiment of the invention has
been described using specific terms, such description is
10 for illustrative purposes only, and it is to be understood
that changes and variations may be made without de-
parting from the spirit or scope of the following claims.
What is claimed is:
1. An apparatus for minimizing pull-through of gas
sition such does not interfere with the draining of the 15 disposed above a liquid in a tank when draining the liq-
fluid from the tank.
 ujd through an outlet provided in the bottom of theAs the liquid level drops, such as shown in FIG. 6, the
baffle slides down the shaft 22 preventing the gas above
the liquid from being pulled through the drain outlet
12. However, the liquid is allowed to flow beneath the 20
baffle 20 through the outlet 12. When the baffle
reaches its lowermost position, such as illustrated in
FIG. 4, wherein the sleeve 28 engages the vertical plate
18, the liquid can still flow between the baffle 20 and
the bottom of the tank through the outlet 12. 25
It is desired to allow the baffle to rise when the liquid
level is high since when such is in its lowermost position
it does restrict the flow of liquid through the tank outlet
12 to a certain extent.
FIG. 7 illustrates a modified form of the invention 30
wherein like reference numerals are used for corre-
sponding parts. The only reference between the struc-
ture illustrated in FIG. 7 and that illustrated in FIG. 4
is that the disc 26 is constructed of any suitable buoy-
ant material, and in one particular embodiment, such 35
takes the form of a thin wall metallic sealed disc shaped
float. The float 26 has a hole 28 passing through the
center thereof for allowing such to ride up and down on
the rod 22. The vertical plate 32 is welded to the bot-
tom of the tank and only extends adjacent the center 40
thereof. Positioned on the outer end of the vertical
plate 32 is a threaded screw 34 which can be rotated
for varying the height at which the baffle is stopped
above the outlet 12. The screw 34 is threaded into the
vertical plate 32. 45
FIG. 8 discloses still another modified form of the in-
vention, wherein, the float 20 is supported on an S-
shaped bracket 36 which is attached by its bottom hori-
zontal flange 38 to the bottom of the tank 10. The
upper horizontal flange 40 of the S-shaped bracket 36 so
has a hole extending therethrough for receiving a rod
42. A sleeve 44 is secured, to the horizontal flange 40
and has a bore extending therethrough in alignment
with the hole extending through the flange 40. The rod
42 is allowed to ride up and down freely through the 55
sleeve 44. The upper end of the rod 42 has threads 46
carried thereon, upon which a nut 48 is carried. The
nut can be adjusted to vary the height that the float 24
is allowed to stop above the outlet 12 in the tank. The
60
tank comprising:
A. a vertical support means carried adjacent said out-
let,
B. a baffle,
C. means for supporting said baffle on said vertical
support means for free vertical movement respon-
sive solely to variations in the liquid level in said
tank,
D. said baffle being supported directly above said
outlet and being buoyant so as to float on top of
said liquid for preventing pull-through of gas dis-
posed above said liquid in said tank while draining
said tank, and
E. means for limiting the downward movement of
said baffle so that when said liquid level drops
below a predetermined level said baffle is held a
predetermined distance above said outlet for allow-
ing the remaining portion of said liquid in said tank
to flow under said baffle through said outlet to
completely drain said tank.
2. The apparatus as set forth in claim 1 wherein:
A. said vertical support is a vertical rod carried in
alignment with the center of said outlet,
B. said baffle is a circular float having a diameter
greater than the diameter of said outlet, and
C. said circular float having an opening extending
through the center thereof through which said ver-
tical rod extends for allowing said float to rise and
fall on said vertical rod responsive to variations in
the level of said liquid in said tank.
3. The apparatus as set forth in claim 1 wherein:
A. said means for limiting the downward movement
of said baffle being adjustable so as to vary the dis-
tance that said baffle is stopped above said outlet
when draining said tank.
4. The apparatus as set forth in claim 3 wherein:
A. said means for limiting the downward movement
of said baffle is an adjustable screw.
5. The apparatus as set forth in claim 2 wherein:
A. an abutment is carried on said vertical rod for lim-
iting the upward movement of said circular float.
65


Floating baffle to improve efficiency of liquid transfer from tanks

NASA TECH BRIEF 
John F Kennedy Space Center. ^^Jt\lv I 
June 1973
	
B73-10190 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Floating Baffle to Improve Efficiency
of Liquid Transfer From Tanks 
The problem: 
Fuel oils, gasoline, and other liquid chemicals de- 
livered by trucks or railcars are transferred from 
tanks by either draining, pumping, or pressurizing. 
Unfortunately many tanks are not emptied completely 
because of the pull-through effect. The pull-through 
occurs when much of the, liquid has been emptied and 
a concave vortex develops within the remaining liquid 
just above the tank outlet. Gas is pulled through 
the outlet with the liquid. By hearing the gurgling 
sound of gas pull-through, some personnel consider the 
tank empty and shut the drain prematurely. The result 
is that gallons of liquid still remain in the tank to be 
carried back and forth, causing unnecessary trans-
portation costs and extra man-hours to complete the 
delivery.
Stop for 
Elevated 
Position 
Shaft 
	
Shaft	 Baffle Guide 
Support
/ 
Attached 
	
To Tank	 Float Tank  
Bottom \
Baffle 
(Lowered 
Level 
	
Liquid	
Position)
The solution: 
A floating baffle guided by the shaft above the tank 
outlet restricts the pull-through. 
How it's done: 
The baffle as shown in the figure is attached to the 
shaft above the tank outlet. It is supported on the liquid 
surface by two small float tanks. When the liquid tank is 
full, the baffle is held up against a stop on top of the 
shaft to prevent the restriction of flow from the outlet. 
As the tank is being emptied, the baffle, floating on top 
of the liquid surface, descends with the liquid level 
toward the outlet until it reaches its bottom stop. The 
baffle prevents gas pull-through until practically all of 
the liquid is emptied from the tank. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: TSP73-10190 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Inquiries concerning non-
exclusive or exclusive license for its commercial develop-
ment should be addressedto: 
Patent Counsel 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
.
Source: Frank S. Howard 
Kennedy Space Center 
(KSC-10639) 
Category 07 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights. 
Tank 
Outlet
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Floating baffle to improve efficiency of liquid transfer from tanks

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