US2988898A - Cooling apparatus for liquid baths - Google Patents

Description

United States Patent Y 2,988,898 COGLING APPARATUS FOR LIQUID BATHS James C. Hessen, Riverdale, and Ralph S. Frost, Matteson, Ill., asslgnors, by mesne assignments, to Chemetron Corporation, Chicago, Ill., a corporation of Delaware l Filed Aug. 4, 1958, Ser. No. 752,938

5 Claims. (Cl. 62-168) This invention relates to apparatus for cooling a bath of alcohol, or the like, by injecting carbon dioxide into Vthe alcohol from a point located below its surface.

,The invention is concerned with systems wherein a fluid such as alcohol to be cooled is .placed in an insuv lated container within which the luidmay be exposed to low temperature and pressure carbon dioxide, usually as snow or a mixture of snow and vapor. In a cooling operation of this type, certain advantages accrue when `the carbon dioxide is injected into the fluid from beneath its surface. 'Ihis operation has the primary advantage that the discharge of carbon dioxide into the 'bath keeps the yluid stirred up to obtain a more uniform temperature. However, the bubbling and splashing of the iuid being cooled limits the rate at which carbon dioxide may be injected and therefore limits the rate of cooling which may take place. Further, the pipe or conduit through which the carbon :becomes cooled, thus tending to cause the carbon dioxide Within the conduit to solidify and clog the conduit.

The `primary object of the invention is to-provide a system for discharging carbon dioxide into a uid bath dioxide is discharged into the bath for cooling purposes which is so designed as to minimize the possibility of freezing up during use.

Another object of the invention is to providel a system for discharging carbon dioxide into a fluid bath for cooling purposes in which the rate of discharge of the carbon dioxide into the bath may be varied over a Ifairly wide a i range.

Still another object ofthe invention isato provide a system for dischargingcarbon dioxide'into a fluid bath yfor cooling purposes and in Awhich regulating apparatus ,for controlling the rate of ow of the-carbon dioxide in '"2' In Ithe accompanying drawingforming a part of this r v specification and in which 'likenumerals' are employed to ,designate like parts throughout the same',` f i A j yFIGURE l is a side elevational view, partially'in cross ,section `ot' a' system -;embodying`.thefpresent invention;

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An elongated conduit 18 of relatively small diameter projectsthrough the cover plate 14 and extends downwardly into the bath to terminate at an open discharge end 20 located well below the surface of the bath 12. The conduit 18 extends to an inlet end 22 which includes an orifice plate assembly 24. For reasons which will be developed, the inlet end 22 of the conduit 18 may be located at a point which is quite remote from the bath 4perature and its corresponding low vapor pressure. The

valve 26 may be controlled by suitable electrical connections to a thermostatically operated switch 30 which in turnis controlled by a temperature-sensitive element 32 which may be suspended within the bath 12.

As best seen in' FIG. l, the discharge end 20 of the conduit18 is bent upwardly and projects slightly within one end of an open-ended riser tube 34 located partially Within the bath 12. As suggested in FIG. l, the conduit 18 may be secured along the outer side of the tube 34, as by welding. The tube 34 projects upwardly from the discharge lend 20 of the conduit18 to an open upper end which is located well above the surface of the bath12,. Due to the fact that both the upper and lower ends of the tube 34 are completely open, the interior of the tube 34 is filled with bath liquid to a depth corresponding to'the surface of the liquid of the bath. An annular cap 36 is mounted upon and Vin spaced overlying relationshipA to the upper end of the tube 34. The Cap 36 may be `secured in position by a plurality of braces such at 38 which may be welded to the cap and to thewalls of the tube 34. j l

In FIG. 3, a longitudinal sectional view `of the orifice plateassembly 24 shows the same as including a coupling 40 having a bore 42 extending therethrough. The coupling40 is externally threaded at each end, the threads 44 being employed in securingthe coupling 40 Vtothe outlet of the valve 26. The opposite end of the coupling -40 is provided With a; conical surface I46 upon which is seatedan orifice plate 48 having a conical skirt 50'Which -is complementary to the surface'46 on the couplingV 40.

The plate 48 is provided with a' centrally located o'riiice 52 through which carbon dioxide is discharged from the bore 42 into the conduit 22. As shown in FIG. `3, the inlet end of the conduit 22 is ared as at 54 to snugly seat upon the conical skirt 50 of the orifice plate so that lFIGURE Z isfarcross sectional view of the apparatus i 'FIGURE 3 is a longitudinal sectional view of an orice plate assembly employed in theapparatus of `FIG. `l.

', In FIG."1, a typical system embodying theinventon is disclsedas including an insulated tank or container 10fwithii1lvvhich`isdisposed the bath of fluid-12,. such as alcohol. The constructionaldetails of the container 10 may vary widely, depending upon the particular applif catioaan'd hence its Structure will `iwi be described in detail other than to `state that it is suitably insulated to reduce the transfer of heat between the outside of the container and the bath 12. The container 10 is provided with a cover plate 14 which in the usual case is provided with an opening such as 16 to permit the escape of carbon dioxide vapor.

:the adjacent end of the coupling. l In operation, liquid carbon dioxide under low tempera- -lture and rpressure from the source 28 may be admitted the plate 48 and the conduit 22 are iirmly clamped to the couplingAl) by the nut S6 which is threaded upon to the bore 42 lbylthe opening of lthe valve .26.. `As stated above, the valve 26 may be suitably connected to the switch 30i to be opened and closed depending upon Athe temperature within the bath 12 as sensed by the element 32. Assuming that the valve 26 is open, the liquid carbon `dioxide is forced through the orifice 52 inthe plate48 and thence into thev interior of the conduitxl. Because of the relatively restricted size ofthe oriiice.,52, the carbon dioxide changes from a liquid state into a mixture of vapor and snow by virtue of its passage through the orice 52. This mixture is discharged from the end 20 of the conduit 18 into the interior of the riser tube 34 and thus into the bath 12. The riser tube 34 and the cap 36 prevent violent bubbling and splashing of the be varied 'within wide limits.

`11`ighrate of discharge of carbon dioxide into `the bath:

By regulating the size or diameter of the oriiice 52, the length of the conduit 18 between its dischargeend 20 andthe location Aof the orifice plate assemblywZtmay Previously, vit was thought 'tobe desirable to maintain the. pressurewithin the" conduit `18 at a 'value well above the triple point (sixty pounds per square inch gauge pressure) in order to'prevent the formation of carbon dioxidesnow within the conduit 18. Also, that the yorifice should be located at apoint quite close to the bath and the conduit 18 should b'e made large and straight "and without internal projections in order that the pressure existing` between the orifice and the discharge end of the Aconduit would be `maintained at substantially atmospheric pressure.

It has been determined that by regulating the size of the oriiice 52 so that the pressure ata point within the conduit 18 just downstream of the orifice, i.e. within, but adjacent to the inlet end 22, is maintained between tive pounds and sixty pounds per square inch gauge, the carbon dioxide within the conduit 18 will consist of a mixture of snow suspended in vapor. So long as the pressure adjacent the inlet end of they conduit 18 is maintained above five pounds per square inch gauge pressure, the carbon dioxide vapor within the conduit will Iflow at a velocity which is sufficient to keep the carbon dioxide snow in suspension and thus permit it to be carried along with the vapor and discharged into the bath 12. Should the pressure at the inlet end of the conduit 18 fall -below iive pounds per square inch gauge pressure, the velocity of How becomes too low for the snow to re- -main in suspension and it settles out and blocks the tube, especially at bends or irregularities.

In'one system, the conduit 18 consisted of a length of approximately twenty feet of copper tubing having a .30 inch inside diameter. Several loops and bends existed in the conduit. The source of supply 28 furnished liquid carbon dioxide at 2 F. to the valve 26 at approximately 300 pounds per square inch gauge pressure. In this system, it was found that successful operation could be achieved where the diameter of the orifice 52 ranged rbetween .021 inch and .042 inch.' An attempt to operate the system with an orifice of .07 inch was unsuccessful since the pressure just downstream of the orifice rose above the triple point and theA tube became clogged.

While we have described but one embodiment of our invention, it will be apparent to those skilled in the art that the disclosed embodiment may be modified. Therefore,'the foregoing description is to be considered exemplary rather than limiting and the true scope of our invention is that defined in thefollowing claims.

Having thus described the invention, we'claim:

ll. Means for cooling analcohol bath, or the like, by the injection of carbon dioxide at low temperature and pressure, comprising a conduit having its discharge end located below the surface of said bath and having its iniet end located at a point remote lfrom said bath, means for supplying liquid carbon dioxide under pressure to the `inlet end of said conduit, means responsive to changes in the temperature of the alcohol bath for varying the supply of the carbon dioxide to said conduit, and means mounted at the inlet end of said conduit providing a iiow restriction for transforming liquid carbon dioxide from said supply means into a mixture of snow suspended in vapor within said conduit, said flow restriction being of such size as to maintain a velocity of ow in the conduit suflicient to keep the snow in suspension until it reaches said discharge end.

2. Means for cooling an alcohol bath, or the like, by thefinjection of carbon dioxide at low temperature and pressure, comprising a conduit of relatively small internal diameter extending into the body of said bath with its discharge end located below the surface of said bath and with its inletend located at a point-remote yfrom said bath, means for supplying liquid carbon dioxide to the inletj end of said conduit, and means defining an orifice through which the carbon dioxide passesintosaid conduit, said orifice having a diameter selected to maintain the pressure adjacent said inlet end at a value of between 5 and 60 pounds per square inch `gauge pressure during normal ow of carbon dioxide through said conduit.

3.. 'Meansfor cooling an alcohol bath or the like by injecting carbon dioxide at low temperature and pressure, into; said bath comprising a conduit'of relatively small internal diameter having its discharge end located below the surface of said bath andhaving its inlet end located lat a point remote from said bath, means for `supplying liquid carbon dioxide to the inletend of said conduit, and iiow restriction means mounted in the inlet end of said conduit, said ow restriction having an efective` ilow area selected to maintain the pressure adjacent said inlet end at a value of between iive and sixty pounds per' square inch gauge pressure during normal ow of carbon dioxide through said conduit.

4. Means for cooling an alcohol bath, or the like, by the injection of carbon dioxide, comprising a conduit extending a substantial distance through the bath having an unobstructed discharge opening located within said bath andhaving an inlet opening located outside the bath, means for supplying liquid carbon dioxide under pressure to the inletl opening of said conduit, and ow restriction means positioned in the path of ow of the liquid carbon dioxide to said inlet opening for transforming the liquid carbon dioxide from said supply means into a mixture of snow suspended in vapor within said conduit, said ilow restriction means having an effective flow area selected to maintain the pressure adjacent said inlet opening at a value of between tive and sixty pounds per square inch gauge for maintaining a velocity of flow in the conduit which is sufficient to retain the snow in susvpension until it reaches said discharge opening.

transforming the liquid carbon dioxide from said supply lmeans into a mixture of snow suspended in vapor within said conduit, said restriction means so controlling the yforming of the snow and 'vapor mixture as to maintain a velocity of flow in the conduit sufficient to retain the snow in suspension until it reaches said discharge opening.

References Cited in the tile of this patent UNITED STATES PATENTS 552,481V Kreisler Dec. 31, 1895 2,081,287 Aldridge May 25, 1937 2,261,808v Morris Nov. 4, r1941 2,759,336 i seefeldt Aug. 21, 1956 FOREIGN PATENTS 92,429 Germany July 6, 1897

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