US 3137143 A
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June 16, 1964 Filed April 225, 1962 R. B. JACOBS ETAL CONDENSING VACUUM INSULATION 2 Sheets-Sheet l Robert B. Jacobs Lewis O. Mullen Donald A.Van Gundy Robert J. Richards Willis G. Steward,
June 16, 1964 R. B. JACOBS ETAL CONDENSING VACUUM INSULATION Filed April 2:5, 1962 2 Sheets-Sheet 2 Robert B. Jacobs` Lewis O. Mullen Donald A.Van Gundy Robert J. Richards W|I||s G Steward,
BY Z. f/M
United States Patent() The invention described herein may be manufactured and used by or'for the Government for governmental purposes without the payment of any royalty thereon.
This invention relates to an apparatus for transfer of liquiied gases, as for example, nitrogen, oxygen, etc., and more particularly to insulation for such apparatus.
In the transfer of liquied gases'from either the production apparatus or from storage containers to other receptacles it is necessary to maintain the respective gases at low temperatures, ranging from 0 F. to approximately 300" F. in the case of liquied oxygen. The temperatures are lower in the case of hydrogen, nitrogen and other gases. Hence, special precautions must be taken in order to avoid losses due to evaporation which are considerable and, in the case of liquid hydrogen and oxygen, to avoid hazards such as possible combustion and explosion. It is, therefore, necessary that the delivery or transfer apparatus not only be strong and durable, but also that its design and construction be such that heat leakage from the ambient atmosphere to the liquied gas be kept at a minimum.
Conventional vacuum insulation to separate a cold region, from`a warml environment may be either dynamic or static. In the dynamic system, Vthe vacuum space is continuously pumped. This system requires a pumping apparatus and the power to run it, be available in the vicinity of the dynamically pumped system. The main problem of the static vacuum system com- Y prises producing and maintaining an adequate vacuum.
In order to maintain a static vacuum, the vacuum space the vacuum space must be treated in some manner so that no 'appreciable amount of gas is desorbed into the vacuum space, and the walls must be impervious to ambient molecules.
It is an object of our invention to provide a means for t j must be absolutely leak tight, the walls and contents of sulated by a gas that is condensable responsive to the particles from being re-evaporated in the vacuum and impairingthe effectiveness `of the insulation.
Other objects and advantages of our invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawingsV in which:
FIGURE 1 is an elevational sectional view of a transfer line and coupling. Y
FIGURE 2 is an exploded view of the transfer line disposed'for "connection between a receiving and a dispensing tank.
FIGURE 3 isa View along line 3-3 of FIGURE 2.
FIGURE 4 is a view along line 4-4 of FIGURE 2.
One illustrative embodiment of our invention is shown in FIGURE 1 in which a transfer line, generally designated at 10, is disposed for connection` to a suitable source of liquied gas. The transfer line is comprised of a plurality of sections 12, 14, and 16.
The receiving end 18 of the transfer line carries a female coupling 20 and the opposite end or delivery end carries a male coupling 22. The transfer line is provided with an outer conduit and an inner conduit 24 and 26, respectively.
Female coupling 20 is mounted on the periphery of outer conduit 24 and is provided with internal threading and an inwardly extending shoulder 25. An insert 28 secured to the inner surface 30 of conduit 24 is provided with an outwardly extending annular shoulder 32. An annular groove 34 provided on the outer periphery of insert 28 is disposed to receive an O-ring seal 36 therein.
A conduit 38 smaller in diameter than conduit 24 is secured to an inner annular surface 39 of insert 28 and extends to partially enclose and to be secured in an annular recess 40 of a member 42. Member 42 is provided with a pair of axial openings 44 and 46 in communication. The liquied gas conducting conduit 26 secured in the smaller opening 46 of member 42 extends therefrom into the intermediate section 14 of transfer line 10. Member 42 includes an inwardly projecting shoulder 43 against which abuts one end 45 of conduit 26.
Conduit 26 is comprised of a pair of portions 48 and 50, portion 48 extends from section 12 into the intermediate section 14 of transfer line 10 and terminates just short of the middleof section 14. Portion 50 vof conduit 26 is slightly spaced from the portion 48 of conduit 26 and extends out of intermediate section 14. The spacing between portions 48 and 50 of conduit 26 permits expansion and contraction of the liquiiied gas conducting conduit. A seamless bronze flexible tube 52 having annular corrugatons is disposed around those portions 48 and 50 of conduit 26 that is within section 14 of line 10. The flexible tube permits the uninterrupted ow of liquied gas while permitting the expansion and contraction.l Y
Portion 50 of conduit 26 extends from intermediate section 14 of the transfer line and thru section 16 thereof.
i Outer conduit 24 terminates at section 16 and is secured to male coupling 22. Coupling 22 is provided with an inwardly extending shoulder 52 and external threading. A conduit 54 abuts against shoulder 52 and is secured to the inner annular surface 55 of coupling 22.
A projecting portion 57 includes conduit 54 which projects out of coupling 22 and encloses a portion of conduit 26 which also projects through coupling 22. An end member 56 is provided with an annular recess 58 and an outwardly projecting shoulder 60. Conduit 54 encloses recess 58 and'abuts shoulder 60 and is soldered to member 56. Member 56 is further provided with a recessed portion 62 into which is positioned a pair of ring members 64 and 66. Y
A vacuum seal off valve 68 is -mounted in outer conduit 24 of line 10. Valve 68 is disposed to be opened to permit charging of the space 70, between conduits 24 and 26, with a condensable gas. Y
As shown in FIGURES 1 and 2, a gas dispensing tank 72 is provided with a projecting portion 74 similar in construction to projecting portion 57 of transfer line 10.V
Projecting portion 74 includes an outer conduit 76 secured at one of its ends to tank 7.2. A male 4coupling member 77 is secured to the other end of conduit 76. An inner conduit 78, partially enclosed by conduit"76, communicates into tank `72` an`d extends therefrom. Male Conduit 87 extends from ymale coupling member 77 to enclose conduit 78 and is positioned at its end -39 into recess 86 of end member S4. The conduit may be secured to member 84 by soldering.
End member 84 Yis provided with an outer annular `surface 91 into which'is positioned a'pair of ring members 90 and 92 which inhibit the flow of liquid between conduits-38 and 87. Ring member 90 is a piston ring which primarily inhibits said flow, while ring member 92 is a spring washer whichholds ring member 90 in the proper v position.
To connect the transfer line to the dispensing tank'the i receiving end 18 of line-10 is slipped over projecting portion 74. Conduit 7 8 extends into section 12 of the transfer line and the ring members 91B and 92 are seated against the inner annular surfaceof recess 44 provided in end member 42. Female coupling 20 is then threaded to male coupling 77 to assure Va tight leakproof seal.
As shown in FIGURE 2, a receiving tank94 is provided with a connecting portion 96 similar to section k12 of the transfer line into which is inserted the projecting portion 57 ofrtransfer line 10. A female coupling 98 provided on connecting vportion 96 is disposed to be threaded to the male coupling member 22 of line 10 to complete the connection.
Thertransfer line is provided with spacers 100 positioned around conduit 26 and secured to conduit 26 to support conduit 26 throughout its length. These spacers are preferably made of Teflon and are substantially rectangular in cross-section to permit the condensable gas to flow around the spacers and fill the space 70.
The space 70 is full of the condensable gas at all times and when the connection is made between the receiving and dispensing tanks the gas is disposed to condense responsive to the cryogenic ow through the line thus creating a vacuum in space 70.
Because the condensate may not adequately adhere to the inner conduits, the inner conduits 26 and 38 are Wrapped with a material 102, having entrapping interstices such as laminated unbonded Fiberglas. Material 102 is disposed to trap solid condensed particles of the condensing gas. Another advantage of this particular type of construction is that the solid particles can adsorb gases. However, in conventional high vacuum insulation, these gases would remain in the vacuum space and serve to deteriorate the vacuum insulation.
Because the trapping material has a high absorptivity for infra-red radiation, the resultant Vacuum insulation would be very poor. Therefore, a highly polished material 104, such as aluminim foil is wrapped around material 102 to provide surfaces of low absorptivity and thus `produce an insulation of high' effectiveness.
While the above discussion has been directed to a transfer line utilizing carbon dioxide as a condensable gas this is to be taken in an illustrative sense rather .than in `a limiting sense. Obviously various modifcationsmaybe resorted to, such as utilizing other condensable media for creation of a vacuum or applying the-principles of the invention to apparatus such vas transport containers, storage tanks, valves, ete., but these modifications are within the spirit and scope of the appended claims.
1. Apparatus for oW of low temperature fluids therethrough comprising:
(a) an elongated outer tubular member having a receiving end provided with a coupling for attachment Yto a supply of cryogenic fluid;
(b) an inner tubular member including a receiving end section disposed in communication with said supply of cryogenic 'luid and secured thereto by said coupling and disposed for cryogenic flow therethrough, 'said inner tubular member axially disposed within said outer tubular member to provide therewith an annular chamber; Y
(c) a condensible gas disposed in said chamber for condensation responsive to cryogenic ilow through said inner tubular member;
(d) a material possessing entrapping interstices wrapped on said inner tubular memberand disposed for adsorbing molecules of said condensible gas for concentration thereofv at said material to provide thereon a layer of solidiiied gas enclosing said inner tubular member and providing insulation thereto, said gas disposed to materially decrease pressure within the chamber for evacuated enclosure of said inner tubular member responsive to the solidication; and
(e) a member forming a radiation shield enclosing said entrapping material and said inner tubular member, said radiation shield and said entrapping material being spaced from said outer tubular member to aid in solidifying and preventing re-evaporation of said solidified gas by keeping said solidified gas from contact with said outer tubular member.
2. The apparatus of claim 1 wherein said entrapping material is glass wool.
3; The apparatus of claim shield is aluminum foil.
4. The apparatus as set forth in claim `1 including rectangular spacers carried by said inner tubular member and secured to the outer surface of said inner tubular member for support therein of said innertubular member.
S. Apparatus as in claim 1 wherein said outer tubular member is provided with a delivery end section:
(a) a coupling carried on said delivery end section for attachment thereof to a receiving tank; and
(b) said inner tubular member provided with a delivery end section extending through said coupling and protruding into said receiving tank.
6. Apparatus as in claim 5 wherein said inner tubular member includes:
(a) an intermediate discontinuous section including a pair of portions in axial alignment, one portion thereof provided with an end disposed adjacent one end of said receiving end section; and
(b) sealing means secured on said adjacent ends and disposed to inhibit cryogenic flow into said chamber.
7. Apparatus as in claim 6:-including a'flexible tube having annular corrugations disposed around said portions and extending over the space between said portions to permit expansion and contraction of said portions.
8. Apparatus as in claim 6 wherein said sealing means includes: v
(ci) a collar mounted on said oneadjacent end of said portion and partially enclosing said one end of said receiving end section; and
(b) a piston ring carried on said one .end of said receiving end section for engagementwith said collar to inhibit said cryogenic flow into said chamber.
`1 wherein said radiation References Cited in the le of this patent UNITED STATES PATENTS OTHER REFERENCES Cryogenics, vol. 1,'March 1961. Article by Kropschot on pages 171-176 relied on.