Very cold liquids and gases such as helium, neon, and nitrogen can be pumped by using magnetocaloric effect. Adiabatic magnetization and demagnetization are used to alternately heat and cool slug of pumped fluid contained in closed chamber

Brown, G. V.

English

NASA Technical Reports Server

August 1973	 B73-10124 
S	 NASA TECH BRIEF 
Lewis Research Center 
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. 
Magnetocaloric Pump 
A unique pump has been designed to pump very cold 
liquids and gases such as helium, neon and nitrogen. 
Pumping is achieved by use of the magnetocaloric effect. 
Adiabatic magnetization and demagnetization are used 
to alternately heat and cool a slug of the pumped fluid
contained in a closed chamber. This alternate heating 
and cooling causes the fluid to alternately expand and 
contract. Unidirectional inlet and outlet valves in the 
chamber alternately open and close to produce a pul-
sating flow of fluid. 
Fluid Outlet 
+ 
Outlet Valve	 Pump Vessel
Solenoid To Provide 
T1
	 Magnetic Field 
Porous, Sintered, 
-J
	
Powdered, Or 
Granular Mass 
Of Magnetic Material 
Heater Coil Or Wire 
(If Required)	 4f	 I	
Inlet Valve 
Fluid Inlet 
Schematic Of Magnetocaloric Pump
(continued overleaf) 
	
This documentwas 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.
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ILI 
Conventionally, cold fluids are pumped by mechanical 
pumps, diffusion pumps, and various other types of 
cyclic and acyclic sorption pumps. Mechanical and 
diffusion pumps can cause contamination of the pumped 
fluid with oil or other substances, and many such pumps 
can operate only at or above room temperature. In 
contrast, the magnetocaloric pump (see figure) does not 
contaminate the pumped fluid, and it can operate at 
or near the boiling point of a fluid. It is, in fact, at the 
boiling point (saturated conditions) where the magneto-
caloric pump is expected to be the most effective. The 
cyclic nature of the magnetocaloric pump permits in-
definite operation, which in many applications would 
be an advantage over acyclic or one-shot cryopumps. 
The pumping chamber contains a porous mass of 
magnetic material and has unidirectional input and out-
put valves. In operation, the magnetic material is mag-
netized by an electromagnet. To start up, using a mag-
netic material having a positive magnetocaloric effect, 
the magnetic material is magnetized. The pump is primed 
and cooled to the same temperature as the fluid to be 
pumped by drawing the cold fluid through the pump 
until the temperatures equalize. The outlet valve is 
closed, and the magnetic field is decreased. This causes 
the fluid in the pump to contract and the reduced pres-
sure draws in more fluid through the inlet valve. In 
cases where cold gases are being pumped, condensation 
may occur at this point of the cycle. The inlet valve 
is now closed, and the magnetic field is increased, caus-
ing the fluid to expand. At the right moment, the outlet 
valve opens, and the expanding fluid is expelled. Alter-
nately, for a magnetic material having a negative magneto-
caloric effect, the magnetization/demagnetization cycle 
is reversed. - 
To increase flow rate, it may be desirable to add 
additional heat to the chamber during the pumping 
cycle. 
This pumping principle has been demonstrated with 
a 4-cm diameter pumping chamber. Saturated helium 
gas at 3 to 4 K was pumped with a magnet varying from
1.5 to 6.0 teslas of magnetic flux intensity and cycled 
once every 15 to 20 seconds. Pressure differences between 
inlet and outlet of 470 mm Hg with no flow and 110 
mm Hg with flow have been created by the pump in 
initial tests. Analysis indicates that with optimum design, 
a pressure difference of more than 740 mm Hg should 
be possible. This would permit the pump to create 
superfluid conditions in a vessel of liquid helium by 
dropping the vapor pressure below 38 mm Hg. 
Notes: 
1. The following documentation may be obtained from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: NASA TM-X-52983 (N71-20943), 
The Practical Use of Magnetic Cooling 
Technical questions may be directed to:
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B73-10124 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
NASA Patent Counsel 
Mail Stop 500-3 11
 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135
Source: Gerald V. Brown 
Lewis Research Center 
(LEW. l 1672)
. 
. 
. 
B73-10124	 Category 07, 03


Magnetocaloric pump

A vessel having inlet and outlet valves is disposed in a container with a fluid to be pumped which may be evolved from a liquid in the container below the vessel. A magnetocaloric substance is disposed in the vessel and causes fluid vapor in the vessel to expand and be expelled through the outlet valve. Vapor is drawn in through the inlet valve as the substance cools. The inlet valves may be one-way check valves or may be solenoid valves energized at appropriate times by timing circutis. A timer controlled heating element may also be disposed in the vessel to operate in conjunction with the magnetic field

REPLY TO
ATTN OF: GP
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON, D.C. 20546
JUL 1 7 1974
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TO: KSI/Scientific & Technical Information Division
Attn: Miss Winnie M. Morgan
FROM: GP/Office of Assistant General
Counsel for Patent Matters
SUBJECT: Announcement of NASA-Owned U.S. Patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. Patent No.
Government or
Corporate Employee
Supplementary Corporate
Source (if applicable)
NASA Patent Case No.
3, tii.zn
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NOTE - if this patent covers an invention made by a corporate
employee of a NASA Contractor, the following is applicable:
YES /— 7 NO A77
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 No. 1 of
the Specification, following the words "...with respect to
an invention of ..."
Bonnie L. Woerner
Enclosure
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United States Patent
Brown
mi 3,819,299
[45] June 25, 1974
[54] MAGNETOCALORIC PUMP
[75] Inventor: Gerald V. Brown, Lakewood, Ohio
[ 73 ] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration, Washington, D.C.
[22] Filed: Nov. 10, 1972
[21] Appl. No.: 305,639
[52] U.S. Cl 417/52
[51] Int. Cl F04b 19/24
[58] Field of Search 417/48, 207, 383, 52, 322
[56] References Cited
UNITED STATES PATENTS
3,029,743 4/1962 Johns 417/505
3,087,438 4/1963 Ciesielski : 417/207
3,139,760 7/1964 Pfieffer. 417/212
3,150,592 9/1964 Stec 417/322
3,270,672 9/1966 Haines..... .:...... 417/322
3,370,538 2/1968 Hines ;..'... 417/322
3,511,583 5/1970 Brown 417/412
FOREIGN PATENTS OR APPLICATIONS
705,646 3/1965 Canada ; 417/383
Primary Examiner—William L. Freeh
Attorney, Agent, or Firm—N. T. Musial; J. A. Mackin;
J. R. Manning
[57] ABSTRACT
A pump for fluids is disclosed. A vessel having inlet
and outlet valves is disposed in a container having dis-
posed therein a fluid to be pumped and which fluid
may be evolved from a liquid in the container below
the vessel. A magnetocaloric substance is disposed in
the vessel and causes fluid vapor in the vessel to ex-
pand and be expelled through the outlet valve when a
magnetic field is impressed on a magnetocaloric sub-
stance of the type which increases in temperature
when subjected to an increasing magnetic field. If the
magnetocaloric substance is of a type which increases
in temperature when subjected to a decreasing mag-
.netic field, then fluid will be expelled from the vessel
when the magnetic field is decreased or terminated.
As the substance cools, vapor is drawn in through the
inlet valve. The inlet valves may be one-way check
valves or may be solenoid valves energized at appro-
priate times by timing circuits. A timer controlled
heating element may also be disposed in the vessel to
operate in conjunction with the magnetic field.
18 Claims, 1 Drawing Figure
PATENTEOJUN25I974 3,819,299
UTILIZATION
DEVICE
-16
20
19/ /
^~ | TIMER
30-
» 3,819,299
1 2
MAGNETOCALORIC PUMP Disposed inside container 10 above the liquid 12 is a
nRIOIN OF THF INVPNTION pump embodyin8 the invention and comprising a suit-ORIGIN OF THE INVENTION
 ab,e yesse, 13 havjng m QUtlet ya,ve 14 and m jnlet
This invention was made by an employee of the U.S. valve 15. The outlet valve 14 communicates with a uti-
Government and may be manufactured or used by or 5 lization device 16 or with the atmosphere through a
for the Government of The U.S. of America without conduit 17 which extends through a port in the top 11
any payment of royalties thereon or therefor. of the container 10. Thus, the interior of the vessel 13
RArrrROUNn OF THF INVFNTION is P6"0*^ and alternately in communication withBACKGROUND OF THE INVENTION
 the -mterioT or me container 10 and with the utilization
This invention relates to pumps and is directed more 10 device 16 or atmosphere. The valve 14 communicates
particularly to a pump for cryogenic fluids. with the atmosphere when the pump is being used to
In addition to transferring fluid from one location to cool a liquid by expelling saturated vapor, as discussed
another, pumps are used to cool fluids and particularly previously.
cryogenic fluids. An example of this occurs where liq- Although the valves 14 and 15 are disposed in the top
uid helium is disposed in a container and which, as a re- 15 and bottom, respectively, of the vessel 13, it will be un-
sult of evaporation, also contains saturated helium va- derstood that the valves may be located at any point in
por. By pumping saturated vapor out of the container the walls of the vessel 14 provided the communication
to the atmosphere, cooling of the liquid is effected. paths are maintained, that is, the outlet valve 14 is
In the prior art, the pumping of fluids has been ac- maintained in communication with a utilization device
complished by a variety of devices such as mechanical 20 16 or atmosphere while the inlet valve 15 is maintained
pumps, diffusion pumps, and various other types of cy- in communication with the interior of the chamber 10.
clic and acyclic sorption pumps. Mechanical and diffu- Inlet valves 14 and 15 may be simple one-way check
sion pumps can cause contamination of the pumped valves. However, outlet valve 14 may be of the type
fluid with oil or other substances which cannot be toler- having a solenoid 18 energized from a first output 19
ated in many instances, as for example, where the 25
 of a timer 20 which received electrical power from a
pumped fluid must be of high purity. Furthermore, power source 21. Likewise, inlet valve 15 may be pro-
many of the prior art pumps can operate only above vided with a solenoid 22 energized from a second out-
certain temperatures, as for example, normal room put 23 of the timer 20. The timer is preferably pro-
temperature, and would be inoperative at a tempera- grammed to alternately open the valves 14 and 15.
ture of, for example, 4.0° Kelvin. 30 Pumping action is provided by a body of magnetoca-
Mechanical pumps in general involve moving parts loric material 24 disposed in the vessel 13. A magneto-
which, of course, make the pump more subject to me- caloric material is one which is either increased or de-
chanical failure. The other types of pumps are gener- creased in temperature when subjected to the magnetic
ally more expensive and complex. field. Examples of such materials are the rare earth ele-
ORIFrTS OF THF INVFNTION " meiUS SUCh ^  Gd' ^  ^ Ce> the transition series ele'BJEC   E I E I N
 ments such M Fe Cr Ni ^  CQ ^  the salts of ^^
It is an object of the invention to provide a fluid two groups. For maximum heat exchange whereby the
pump having a minimum of moving parts. fluid being pumped is heated and cooled by the magne-
It is another object of the invention to provide a tocaloric body 24, the body is porous and may be made
pump which does not contaminate the fluid being 40 by sintering, granulating or otherwise providing open-
pumped, ings in such magnetocaloric body. To the end that a
Still another object of the invention is to provide a magnetic field will be applied to the magnetocaloric
pump which is particularly suitable for pumping ex- material 24, a solenoid winding 25 is disposed around
tremely cold vapors, for example, as low as 4.0° Kelvin. the vessel 13. Solenoid 25 is energized from a third out-
45
 put 26 of timer 20. Preferably the magnetic field is sup-
Yet another object of the invention is to provide a plied by a super-conducting magnet for maximum ef-
pump which is specially effective in pumping saturated fectiveness.
vapors at a high rate of delivery. To increase the pumping rate and efficiency of the
Another object of the invention is to provide a pump pump a heating element 27 may be disposed around or
for fluids which either expand or contract when heated. in the magnetocaloric material. The heating element 27
is energized from a power source 28 by means of a
It is a further object of the invention to provide a timer 29, the operation of which will be described pres-
pump suitable for cooling liquid in a closed container. ently. In order that the heating element 27 will be ener-
• . .
 g. gized during the time when pumping action is occur-
RRIFF nFSCRIPTION OF THF DRAWING ri"8'that * Whe" flu'd 'S bei"g ^ P6"**1 from the vesselB IE  DESCRIFI ION  E I
 13 by way rf ^ Qutlet ya,ve J4 a synchronizing ,ead
The single FIGURE is a schematic drawing of a mag- 30 is connected between timer 29 and timer 20. It will
netocaloric pump embodying the invention. be understood by those skilled in the art, that depen-
„„„ ~™^XT ^r A r.r.r~r-™r.r~ri ^ . frw^.i«-XTT *« dent upon the electrical requirements of solenoid 25,DESCRIPTION OF A PREFERRED EMBODIMENT 60 ^J"
 lg ^  ^ ^  the
4
heater e,ement 2?> ^
20 and 29 could be combined in one unit as is also pos-
Referring to the single FIGURE, there is shown a sible with the power sources 21 and 28.
suitable container 10 having a closed top 11. Container Operation of the magnetocaloric pump will now be
10 may be partially filled with a liquid 12 such as he-
 65 described. It will be assumed that the magnetocaloric
Hum, nitrogen, hydrogen, or neon, although operation body 24 has a positive effect, that is, it increases in tem-
is not restricted to these particular liquids. For exam- perature when subjected to a magnetic field. It will be
pie, the pump will also operate when the liquid is water. understood that there are magnetocaloric materials
3,819,299 « |k
3 4 ' V
which have a negative effect and would require the a vessel disposed in said container;
valves 14 and 15 to be opened for conditions under an inlet valve disposed in a wall of said vessel;
which they would be closed for a material having a pos- an outlet valve disposed in a wall of said vessel, said
itive effect. second valve communicating with a port in the wall
Pumping action is initiated by filling the vessel 13 5 of said container;
with a fluid to be pumped thus ensuring that the magne- a body of magnetocaloric material disposed in said
tocaloric material 24 is at the same temperature as the vessel; and
fluid. This may be done with the magnetic field either . means for subjecting said body of magnetocaloric
off or on. If the pump is primed with the magnetic field material to a time-wise varying magnetic field to
on, a reduction or termination of the magnetic field will 10 cause alternate expansion and contraction of the
cause the magnetic material 24 to cool and the fluid in fluid.
the vessel 13 will contract drawing in more fluid 2. The apparatus of claim 1 and including means for
through the valve 15. If the valve 15 is of the solenoid alternately opening said outlet valve and said inlet
type the timer 20 will cause the solenoid to be ener- valve.
gized to open the valve during the time the fluid is con- 15 3. The apparatus of claim 1 wherein said inlet and
tracting. outlet valves are one-way check valves.
To expel the fluid from the vessel 13 the magnetic 4. The apparatus of claim 1 wherein said last named
field is again impressed on the material 24 by supplying means comprises a magnetic winding disposed around
or increasing the current to the solenoid winding 25 to said vessel and means for supplying an alternately in-
cause heating of the material 24. This expands the fluid 20 creasing and decreasing electrical current to said wind-
in the vessel 13 causing it to be expelled through the ing.
outlet valve 14 and through the conduit 17 through the 5. The apparatus of claim 1 wherein said last named
utilization device 16. The outlet valve may be of the so- means includes a superconducting magnet,
lenoid type in which case the solenoid 18 is energized 6. The apparatus Of claim 1 and including a heating
by the tinier 20 during the period of time that the fluid 25 element disposed in said vessel and means for energiz-
in the vessel 13 is expanding. The magnetic field is ing said heating element simultaneously with the ex-
again either terminated or reduced and the cycle is re- pansion of the fluid in said vessel,
peated. 7. The apparatus of claim 1 wherein the magnetic
As explained previously, the heating element 27 may field is of such intensity that the temperature of said
be energized simultaneously with the solenoid 25 to iin- 30 magnetocaloric material does not rise above the boiling
crease the pumping action by providing additional heat point of said liquid, when said liquid is water,
to expand the fluid in the vessel 13 where the fluid is 8. The apparatus of claim 1 wherein said inlet and
one which expands when heated. There are certain flu- outlet valves are solenoid type and including a power
ids, which contract when heated within certain temper- supply for said solenoid valves and timing means for
ature ranges. An example is water between 0° and 4°C. 35 opening said outlet valve when fluid in said vessel is ex-
With such fluids it will be understood that, if the valves panding and for opening said inlet valve when fluid in
14 and 15 are solenoid types rather than one-way said vessel is contracting.
valves, they must be actuated in reversed order to their 9. The apparatus of claim 1 wherein said inlet valve
normal sequence. is disposed in a bottom wall of said chamber and said
The magnetocaloric pump embodying the invention 40 inlet valve is disposed in a top wall,
is most effective for pumping saturated vapors. Such 10. The apparatus of claim 1 wherein said magneto-
vapors have a temperature equal to the boiling point of caloric material is porous.
the liquid 12. If the liquid is helium, for example, the 11. The apparatus of claim 1 wherein said magneto-
boiling point is —269°C or 4.2°K. caloric material is a rare earth.
The liquid 12 need not be in the container 10. The 45 12. The apparatus of claim 1 wherein said magneto-
requirement for the pump to work is that the inlet valve caloric material is the salt of a rare earth.
15 be in communcation with a fluid to be pumped. 13. The apparatus of claim 1 wherein said magneto-
Thus, a fluid" could be supplied to container 10 from a caloric material is a transition of element.
supply of the fluid being pumped. For example, the 14. The apparatus of claim 1 wherein said magneto-
magnetocaloric pump embodying the invention may be 50 caloric material is the salt of a transition element,
used to pump natural gas. In such an arrangement, the 15. The apparatus of claim 1 wherein said container
pipe carrying the natural gas and the source of the gas is partially filled with a liquid.
would be the equivalent of the container 11. 16. The apparatus of claim 11 and including means
It will be understood that changes and modifications to heat said liquid to a temperature greater than its
may be made to the above-described magnetocaloric 55 boiling point temperature.
pump without departing from the spirit and scope of 17. The apparatus of claim 15 wherein said liquid is
the invention as set forth in the claims appended selected from the group consisting of helium, hydro-
hereto. gen, nitrogen and neon.
What is claimed is: 18. The apparatus of claim 1 and including receiving
1. A fluid pump comprising 60 means communicating with said port in said container
a container filled with a substantially nonmagnetic, wall to receive fluid expelled from said pump,
nonelectro f l u i d t o b e pumped; * * * * *
65


Magnetocaloric pump

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