US2534334A - Cold treating method and apparatus - Google Patents

Description

De. 19, 195o P, M, AHLSTRAND 2,534,334

COLD TREATING METHOD AND APPARATUS Filed June 30, 1945 INVENTOR PHILLlP M. AHLSTRAND l BY ATTORNEY Patented Dec. 19, 1950 COLD TREATING METHOD AND APPARATUS Phillip M. Ahlstrand, Kenmore, N. Y., assignor to The Linde Air Products Company, a corporation of Ohiol Application June 30, 1945, Serial No. 602,462

17 Claims. (Cl. 62-1) This invention relates to the art of refrigerating or cooling metal parts and other articles, particularly to facilitate the fitting and permanent assembly of such parts within recesses in other machine elements. This invention is an improvement on the cold treating machine disclosed in application Serial No. 539,760, filed June 10, 1944 by Edward L. McCandless. George W. Patch, Jr., and Phillip M. Ahlstrand, which has now eventuated into Patent #2,487,821, dated November 15, 1949, for Method of and Apparatus for Cooling and Dispensing Objects and relates particularly. to a method and means for diluting the spent cooling medium before it is discharged into the atmosphere and for preventing frosting of exposed portions of cooling and dispensing equipment embodying the principles disclosed in said application.

In operating cold treating apparatus which utilizes a moisture-free highly volatile liquefied gas,

. such as liquid oxygen or liquid nitrogen, as the medium for cooling metal articles by indirect heat exchange with a body of the liquefied gas and by direct contact with a vaporized portion of said body of gas, the discharge of the spent vaporized gas directly into the atmosphere adjacent the apparatus produces an undesirable or hazardous concentration of the gas about the operator. Also, an undesirable accumulation of frost occurs on the cold exposed metal portions of the cooling chambers or tubes and the discharge chute which are exposed to the moisture in the atmosphere adjacent the inlets and outlets where the metal articles are inserted and removed.

Therefore, the principal objects of this invention are: to provide a method and means to overcome the above-mentioned objectionable features of prior cold treating equipment; to provide a method and means for effectively eliminating the frosting of exposed portions of such equipment; and to provide a simple and effective method and means for diluting the spent vaporized gas before it is discharged into the atmosphere adjacent the machine, and for utilizing such diluted spent gas to prevent frosting adjacent an inlet of the cold treating machine. The above and other objects and the novel features of the invention will become apparent from the following description considered with the accompanying drawings. In the drawings,

Fig. 1 is a central vertical sectional view of a cold treating apparatus embodying this invention; a

Fig. 2 is a front elevational view of a. part of the apparatus shown in Fig. 1; and

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 1.

According to the invention, the vaporized cooling medium, after it has been used to cool the metal parts to be treated, passes into a suitable chamber where it is diluted with air, after which the gas-air mixture is discharged into the atmosphere and against exposed inlet portions of the cold treating machine, to prevent frosting of said portions and also to avoid an undesirable concentration of the cooling gas adjacent the machine. The air used to dilute the spent vaporized gas may be at room temperature or may be heated above room temperature, and such air may first be passed over a part or parts in thermallyconductive relation with exposed outlet portions of the machine, to prevent frosting of such outlet portions. The relatively warm air preferably is used and mixed with the vaporized gas in such proportion that the diluted vapor will be brought to or slightly above atmospheric temperature and is diluted to such an extent that no hazard attends its discharge into the ambient atmosphere.

As illustrated in the drawings, a cold treating machine embodying this invention may include one or more tubes T of thermally-conductive metal, to provide chambers Within which the metal articles P are refrigerated While being confined out of contact with the atmosphere. The refrigerant or cooling medium preferably is a body L of highly volatile liquefied gas having a low-boiling point, such as liquid oxygen or liquid nitrogen, confined in a container G which is provided with a filling pipe F to partly flll the container with liquid gas and leave a space V above the liquidlevel to contain the vaporized gas. A considerable portion of each tube T extends through the liquid L; anda vertical passage or pipe Il! conducts cold vaporized gas from the space V through the liquid L into each tube T adjacent the discharge end of the latter. By heat transfer from the parts P and by heat leakage into the container G, the liquid L is gradually vaporized and the gas in the space V is maintained at suiiicient pressure to force cold vaporized gas through the pipe I0 into the tube T and then lengthwise of the tube T in a countercurrent direction relatively to the direction of advance of the articles P, to directly contact and cool the latter while they are being indirectly cooled by heat transfer therefrom through the thermallyconductive wall of the tube T that is in contact with the liquid gas L. The parts P eventually and before removal from the tube T, are cooled to near the temperature of the liquid-L.

Near its front or inlet end, each tube T communicates with a mixing and diluting chamber E through a pipe II provided with suitable means, such as a ap valve I2, to prevent return flow of diluted gas from the chamber E. Air, for diluting and warming the spent vaporized gas, is supplied to the chamber E through a conduit K connected to the discharge outlet of a blower R having an air inlet S and driven by an electric motor M. The air entering the inlet S may be at room temperature but, if desired, an electric heater W may be provided to increase the temperature of the diluting air.

The metal articles P to be cold treated are inserted one at a time through the exposed inlet portion of the tube T which normally is closed by a pivoted automatically-closing closure A. 'I'he insertion of an article P serves to push and advance those articles already within the tube T and pushes an article at the outlet end of the tube into a recess I3 in a pivoted trap-door or transfer device D operable to transfer the I article to a downwardly and forwardly inclined metal delivery chute C.

The trap-door D may be operated by any suitable mechanism. As shown, an arm vI4 is rigidly connected at one end to the trap-door and is pivoted at its 4other end to a rod I5 which extends through a tube I6 to the front end of the machine where it is provided with a handle I1, whereby the operator may press the rod I rearwardly and rock the device D to release a cold treated article into the chute C. A spring I8, connected to the arm I4 and to the chute C, automatically restores the transfer device D to a position to register its recess I3 with" the outlet of the tube T to receive another article P. The device D carries a projection or closure I9 which closes the outlet end of the tube T during the transfer of an article, to reduce ow of vaporized gas into the delivery chute. A casing 20 gastightly encloses the transfer device D and, in cooperation with the tube T and the chute C, pro vides a gas-tight chamber for the articles from the inlet to the outlet of the machine. Also, the trap-door D serves to inhibit frosting of the articles in the machine by substantially preventing air circulation through the article chamber, thereby delivering the treated articles in a cold dry condition.

A housing H, packed with heat insulation I, encloses the liquid container G, the chamber E, the casing 20, the major portions of the tubes T and the chute C, and members associated therewith, to inhibit heat leakage to the cold treating liquid and the chambers associated therewith.

As shown, the inlet ends of the tubes T project outside the front of the housing H, and the outlet end of the chute C projects outside of the housing into a receptacle or tray X open to the atmosphere and into which the cold treated articles are delivered by opening the pivoted automaticallyclosing closure B. Moisture in the atmosphere normally condenses as frost on these exposed cold passage portions of the tubes T and the chute C and their closures. In order to prevent such frosting on the inlet ends of tubes T the relatively warm diluted gas from the mixing chamber E is discharged against such inlet ends. For this purpose, a hood or deflector N is mounted on the housing H above the exposed tube ends and its interior communicates through one or more passages 2I with the chamber E. The warm diluted gas thus is discharged into the atmosphere through the lower open side of the hood and directly against the inlet ends of the tubes T and their closures to inhibit frost condensation on these parts. Frosting adjacent the outlet end of the chute C is effectively prevented by forming the air conduit K so as to provide a chamber 22 therein and extending around the chute adjacent its outlet, whereby the relatively warm air ilowing through the conduit will warm the exposed outlet end of the chute and its closure.

The motor M and the blower R with its air inlet may be mounted in a compartment 23 open to the atmosphere through holes 24 and located below the partition 25 which supports the liquid container G, its associated elements and the thermal insulation I. The cold treating machine disclosed herein may be equipped with safety devices, liquid drain pipes, a liquid level indicating means, and other auxiliary devices, as shown in the above-mentioned application Serial No. 539,760. Moreover, a single chute C may be used to deliver the treated articles from the several cooling tubes T, or an individual delivery chute may be provided for each tube. Also, the feature of diluting the spent cooling gas may be employed independently of the frost-eliminating feature; and a current of room air or warm air only may be utilized to eliminate frosting at the inlet or the outlet, or at both inlet and outlet.

From the foregoing it will be evident that the operator located at the front of the machine may open the closure A and insert articles one at a time into the tube T; may release a cold-treated article into the chute C by pressing the handle I'I inwardly; and may withdraw the treated article from the chute by opening the closure B. The cold treated article may then be placed into the recess of the machine element to which it is to be secured, there warming to room temperature and expanding against the wall of the recess to provide a tight and permanent joint between the article and the machine element.

The herein-disclosed cold treating machine illustrates but one embodiment of this invention, the novel principles of which may be utilized in other types of cold treating machines, particularly those which employ a low-boiling point, liquefied gas and a vaporized portion thereof as a cooling medium.

What is claimed is: f'

1. A method which includes cooling a metal article to prepare it for assembly in a recess in a cooperating member, such method comprising placing said article in a cooling chamber normally closed to exclude atmospheric moisture and consequent deposition of frost on said article; passing through said chamber, and directly into contact with said article, a cold gas produced by vaporizing a liquefied gas selected from the group consisting of liquid oxygen and liquid nitrogen; after said cold gas leaves said chamber and before it is discharged into the atmosphere, diluting such cold gas with air at room temperature; and thereafter discharging such diluted gas into the atmosphere.

2. Apparatus for cooling an article comprising, in combination, an article chamber for enclosing an article to be cooled; means for subjecting an article in said chamber tothe cooling eiect of a gaseous cooling medium; a mixing charnber adapted to receive such cooling medium after the latter has been used to cool said article; and means for supplying air to said mixing chamber to dilute the cooling medium therein before itis discharged from said apparatus.

3. Apparatus for cooling an articlecomprising,

in combination, an article chamber to enclose said article; means for supplying a cooling gas to said article chamber to cool an article therein; a mixing chamber communicating with said article chamber to receive gas therefrom; means for supplying air heated above the temperature of the atmosphere to said mixing chamber to dilute the gas in the latter; and means for discharg- .g

ing diluted cooling gas from said mixing chamber into the atmosphere.

4. Apparatus for cooling an article comprising, in combination, an article chamber of thermallyconductive material adapted to enclose an article and thermally insulated except an yarticle passage cle inlet portion thereof and an article outlet portion thereof exposed to the atmosphere; means for cooling said chamber and an article therein to a temperature at which atmospheric moisture tends to deposit as frost on such exposed portions; and means operable to warm both the exposed inlet portion and the exposed outlet portion of said chamber to inhibit frost deposition on such portions.

6. Apparatus for cooling an article comprising, in combination, an article chamber adapted to enclose an article and having an article passage portion thereof exposed to the atmosphere; means for subjecting said chamber and an article therein to the cooling eect of a gaseous cooling medium; a mixing chamber adapted to receive said cooling medium after the latter has been used to cool said article; means for supplying air to said mixing chamber to dilute the cooling medium therein; and means for discharging the diluted cooling medium from said mixing chamber against such exposed passage portion of said article chamber.

'means for conducting vaporized gas from said gas space into said article chamber; a mixing chamber communicating with said article chamber to receive vaporized gas after the latter has been used to cool said article; means for supplying air to said mixing chamber to dilute the vaporized gas in the latter; and means for discharging diluted vaporized gas from said mixing chamber into the atmosphere and against the article inlet portion of said article c hamber.

8. Apparatus for cooling an article, as claimed in claim 7, wherein said article chamber also has an article outlet portion, and such air supply means includes a conduit constructed and arranged to conduct such diluting air into heat exchange relationwith saidy outlet portion to inhibit frost deposition on the latter.

9. Apparatus for cooling metal articles to condition them for assembly in recesses of metal members, such apparatus comprising, in combination, a container adapted to hold a. body of liquefied gas selected from the group consisting of liquid oxygen and liquid nitrogen, said container providing a'y gas space to hold vaporized gas above a liquid level in said container; an article chamber having a part extending into a body of liquid when in said container and having an article inlet portion exposed to the atmosphere, said article chamber also having an article outlet portion exposed to the atmosphere and located below said inlet portion; a conduit connecting said gas space to the interior of said article chamber, to conduit vaporized gas into said chamber; a mixing chamber; means connecting said article chamber to said mixing chamber at a point between said inlet portion and said conduit, to conduit vaporized gas into said mixing chamber; means for supplying air to said mixing chamber to dilute vaporized gas in the latter, such air-supplying means including a pipe opening into said mixing chamber and having a portion constructed and arranged to conduct air into heat exchange relation with said article outlet portion to inhibit frost deposition on the latter; a housing enclosing said liquid container and said article chamber except the exposed inlet and outlet portions of the latter; passage means extending outside said housing for discharging diluted gas from said mixing chamber; and deflecting means outside said housing and adjacent said passage means, for deecting discharged diluted gas against said exposed inlet portion to inhibit frost deposition on the latter.

10. The method which comprises contacting an article with a vaporized refrigerant, subsequently diluting the vaporized/refrigerant with a gas at a different temperature, and before such dilution heating at least one of said gas and said refrigerant.

1l. Apparatus for cooling an article comprisinga container for avaporizable liquid refrigerant and vaporized refrigerant above the level of such liquid refrigerant, a chamber in which vaporized refrigerant is brought in contact with said article, and a passage extending to a substantial extent through the liquid refrigerant and down which the vaporized refrigerant moves from above the level of said liquid refrigerant in said container to said chamber remote from the end portion of said chamber through which said article enters said chamber.

l2. In a cold treating apparatus, in combination, a container for both a vaporizable liquid refrigerant and a vaporized portion of such liquid; a thermally-insulated housing enclosing said container; a thermally-conductive tube adapted to confine the work therein and extending from adjacent said container into the atmosphere outside said housing; means for conducting vaporized refrigerant from said container into said tube and into contact with such work, whereby such work is cooled and such outside portion of said tube is cooled to a temperature that tends to cause frost deposition thereon; and means extending through said housing for applying a warming medium to said tube adjacent such outside portion thereof 'to inhibit frost deposition on said outside portion.

13. In a cold treating apparatus, as claimed in claim 12, said means for applying a warming medium adjacent such outside portion of said tube including a blower for discharging adjacent such outside portion a gas adapted to inhibit such frost deposition.

14. In a cold treating apparatus, in combination, a container for both a. vaporizable liquid refrigerant and a vaporized portion of such liquid; a thermally-insulated housing enclosing said container; a thermally-conductive tube adapted to confine the work therein and extending from adjacent said container into the atmosphere outside said housing; means for conducting vaporized refrigerant from said container into said tube and into contact with such work, whereby such work is cooled and such outside portion of said tube is cooled to a temperature that tends to cause frost deposition thereon; and means for applying a warming medium to said tube adjacent such outside portion thereof but within the apparatus to inhibit frost deposition on said outside portion, said means for applying a warming medium adjacent such outside portion of said tube including a blower for discharging adjacent such outside portion a gas adapted to inhibit such frost deposition.

15. A method of reducing thetendency to frost deposition on a thermally conductive article passage projecting from a refrigerating apparatus which comprises heating a portion of air to above the temperature of the atmosphere and Warming the projecting article passage by passing said heated air portion across it when mixed with cold gas from within said apparatus, said warming o1' the article passage by heated air passing across it occurring both outside and inside or said apparatus.

16. A refrigerating apparatus having a thermally conductive passage projecting out of said apparatus and through which an article may be moved in cooling the same, means for supplying cold gas to said passage, a heater, means for passing air from outside the apparatus through said heater, and across said passage within said apparatus in discharging vsaid heated -air from said apparatus.

17. Apparatus according to claim 16 in which a second passage is provided for cold gas from within said iirst passage and leading to a mixing chamber wherein the heated air and cold i gas may be mixed before their discharge.

PHILLIP M. AHLSTRAND.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 753,045 Cooper Feb. 23, 1904 1,371,546 Bollman Mar. 15, 1921 1,978,204 Hurt oct. 23, 1934 2,309,007 Parsons Jan. 19, 1943 2,399,679 Jackson May 7, 1946 2,487,821 McCandless Nov. 15, 1949

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