US2244904A - Refrigeration system - Google Patents

Description

June 10, 1941. H. A. B. BROWN REFRIGERATION SYSTEM Filed May 1, 1939 2 Sheets-Sheet 1 INVENTOR Harry ,4. B. Era wn ATTORNEYS June 1941- H. A. 5. BROWN REFRIGERATION SYSTEM 2 Sheets-Sheet 2 Filed y 1. 1939 INVENTOR Harry 4.15. Eran n 4 ATTORNEYS Patented June 10, 1941 UNITED STATES. PATENT OFFICE 2,244,904 asrameas'non srs'rsu m .4. a. Brown, sill Calif. Application my 1,1939, Serial No. 271.052

' 4 Claims. (cl. lie-91.5)

This invention relates to a refrigeration system which uses a fluid refrigerant and in which the motive power for actuating the flow of the refrigerant to the point or points where evolving is tozbe effected by transfer of heat to the refrigerant, is independent of mechanical or electrical power. Another object is an improved, economical system of refrigeration in which the refrigerant, such as ethyl chloride, or other fluid having a relatively low freezing point is moved in a closed circuit including a heat exchange coil or the like, and is cooled before movement into such coil by solid CO2, or dry ice, with the motive power for causing the movement being supplied by CO: gas pressure resulting from sublimation of the dry ice caused, principally, by the transfer of heat units from the refrigerant to the dry ice during movement of the refrigerant in apparatus, certain elements being shown in elevation.

Fig. 3 is an enlarged elevational view of one of the elements of the'portion illustrated in Figi 2.

Fig. 4 is a sectional view along the line 4-4 of Fig. 3.

Fig. 5 is a sectional view along the line 5-4 of Fig. 3.

Fig. 6 is a sectional view along the line 6-4 of Fig. 3.

fig; '1 is a sectional view along line 1-1 of Fig. Sis a diagrammatic view of a modified form of the invention;

In detail. referring to Fig. 1, I show anair tight tank I, containing dry ice 2, which tank is provided with an inner bottom 3 and an outer "bottom I, thus forming a double bottom with a space I between said inner'and outer bottoms with an inlet conduit t opening into said space at one point and an cutlet conduit 1 communieating at one end with said space at another point, the inlet and outlet openings into said space being preferably at opposite sides of the tank so that a liquid entering the space from the inlet opening will pass over. substantially the full area of space and out through the outlet.

The inlet and outlet conduits with the space 6 thusvirtually constitute one continuous conduit for a liquid refrigerant having a low freesing point, such as ethyl chloride, Freon, sodium chloride, and the like. and the heat unit in the refrigerant flowing from the inlet to the outlet between the bottoms 4, I, will-be readily absorbed by the dry ice in container i. The walls of container I are, of course, preferably heat insulated in the usual manner, and a closure I is provided for filling the container with dry ice, and a pressure relief valve I is also provided for preventing dangerous pressure in the container by reason of the CO: gas.

Conduit I leads to a conventional cooling or heat exchange coll ll positioned in the area to be cooled. If in a car or compartment, the coil is preferably at the top of the same,\ or-said cooling coil may obviously be placed wherever a cooling result is desired.

A continuation ll of the cooling coil opens into a closed tank or receptacle 12 at the upper end of the latter, and a pipe It opens into the bottom of said tank, the opening being preferably covered by a screen |4.

The pipe ll extends downwardly from tank l2 and is' provided witha check valve II, and a manually operated cut-off valve IO, and continues past the cut-off valve and through a cover Il (Fig. 2) into the upper portion of a container It. The continuation from the cut-off valve into the container ll may be provided with the conventional union for disconnecting the portion extending into said receptacle from the conduit it to facilitate removal of cover II from the con- 'tainer.

' cylindrical sided, hollow, open-ended, valve memher I. disposed co-axially with the casing and rotatable therein about its axis. The cylindrical wall of casing II is formed with a pair of ports 2i, 22 (Figs. 3 to 5) and a pipe 23 extends between port 2| and a pointin one of the walls of tank I, preferably somewhere above the bottom of said tank, while an exhaust pipe 24 communicates between port 22 and the atmosphere.

The ports 2|, 22 are at points in longitudinal alignment in direction axially of the axis of the casing, and valve II is also ported at 2|, 22, which ports 2|, 22' are similar in size to ports 20, 2| and are positioned so that port 2! will register with port 2| in one position of the valve,

of one end of easing ll. pin ll projecting radially thereof and into an valve, but upon rotating the valve a predetermined distance about its axis. the port 22' therein will register with port I! and ports 2| will move out of registration with port It to close port 2i by the wall of said valve adjacent said port ii. The movement of valve II is an cillating one, rather than full rotation of the valve, so that about a quarter of a turn of the valve in opposite directions will bring ports 2|, it into registration at one end of the movement and ports 22, 22' will be in r tlstration at the other end of said movement, but ports 2|, II, and 2 2, 22' will not be in registration at one time, aswill hereinafter be described.

In pipe 23 isa check valve 25, and between check valve 25 and tank i is a thermostatically controlled valve 2', which latter valve is actuated by a conventional thermostatic device 11 pomtioned adjacent the cooling coil II or in the area to be cooled.

From the foregoing, it is seen that when ports 2!, II are in registration, and valve 28 is open. communication is established between container it and tank I.

For convenience in removal of cover i'i with the valve assembly connected thereto, a conventional union may be in the section of pipe 23 between check valve 2! and the cover.

The conduit 8 has a check valve 2| therein and said conduit communicates between the space i between bottoms 3, 4 of the tank I and the bottom of container it, said check valve 2! permitting flow of liquid from. container ll to space i, but preventing back flow.

Referring to Figs. 2 to 6, thevalve assembly within the container It includes the valve casing it and valve ll with ports 2|, 2i, 2!, 21', as already described. The rotation of valve is is effected by a rotary shaft 2! in axial alignment with the central axis of the valve, one end I! of which shaft projects within an extension 30 of valve I! that projects outwardly The end 28' carries arciiate slot 3! extending clrcumferentially in said extension 30. i v

sum is alsocarries a disk is at a point spaced outwardly of the extension SI of the valve.

which disk is free for rotation on shaft 20, and.

carries an arm 84 extending radially outwardly therefrom, the outer end of said arm having a hollow ball float member secured thereto.

The disk 33 is formed with a recess 3| opening outwardly at a point around the periph thereof (Figs. 3, 6) in which recess one end of a pin 31 is received. The pin 31 extendsaxially of shaft II and is secured at its opposite end -to the outer end of a short arm 89, theinner end of said arm being secured on the end of shaft ll that is remote from valve ll. The pin 31 extends through said arm to project outwardly therefrom at the side thereof opposite disk 83, as at ll (Figs. 3, 6), and a tension coil spring is secured at one of its ends to end it of the pin. the opposite end of the spring being secured to cover II in any suitable manner at a point. it directly over the axis of shaft 29 and in a plane perpendiculartotheplaneofcover il. l

. Between arm a annals: a, and between 33 and valve II are bearings 42 rotatably supporting the shaft '28 and suspending the shaft from the cover. The bearing adjacent arm I! projects at its outer end, laterally (relative to the shaft 29), a. suflicient distance to be engaged by the portion of pin I'ithat extends from arm ll to recess 38 when the shaft is rotated in one direction, thus forming a stop against further rotation of the pin in said one direction, and when the shaft is rotated in the opposed'direction the outer end of the bearing likewise forms a stop -agalnst furtherrotation in said other direction.

The action of spring ll during such rotation is to yleldably resist the rotation in one direction or the other until the arm It moves across the central axis of the shaft, and thereafter the spring tends to forceably rotate the shaft during the remaining movement. Thearmllthatcarriestheballiloatllalso carries a disk valve 43 on its upper side, which disk valve is adapted to closely seat over theend of pipe I: that extends through the cover i'l into container it when the container is substantially filled with liquid and the ball float is in its hi hest position (Fig. 2).

When the container I8 is fllled, and ball float ii is in the position illustrated in Fig. 2, the valve I! is in a position in which ports II, it are in registration, and in which 00: gas from tank i can flow into container it, provided the thermostatic valve 20 is open. Also, in this position, no liquid can flow into container II from the tank if, since valve 41 closes the pipe it against such flow. However, upon lowering of the level of liquid in container it, the ball float 3! will fall, causing rotation of shaft 29 and also rotation of the disk 38, through the one end wall ofthe recess in disk as being in engagement with the pin 31. The slot 32 in extension 30 of the valve it extends circumferentially thereof and pin Ii that extendsinto said slot wil be moved from one end of the slot to the other as the shaft 2! revolves under the influence of the descendin ball float. When pin 31 is moved across the axis of shaft 2!, the pin 31 will be moved into engagement with the said other end of slot 32 and then spring ll will react to quickly rotate the shaft around a sufllcient distance to quickly rotate the valve M from position with ports 2|, ii in registration with each other and to close port 2|. Upon liquid flowing into container ll through pipe ii, the ball float will rise. and the valve assembly will be restored to the position indicated in the drawings.

From the description thereof thus far, it is.-

seen that the cooling coil and its extension ll,

'the tank l2, conduit ll, container l8, coiidllit C,

fAlso considering that the liquid refrigerant sub.-

stantially fills the closed circuit as described to the level of the top of tank i2,.it will be obvious that there will be a gap in such circuit that includes part or all of the'coolingcoil il, or at least some of the circuit above the level of liquid insaidtankii.

In operation, with; the circuit fliled to wa tent described above, and with dry ice in the container i, it is obvious that a C02 gas pressure in container 1 will be built up, the sublimation of.v the dry ice to produce said gas being more or less controlled by the temperature of the liquid refrigerant in space I between the bottoms 3, 4. Upon a predetermined risein temperature in the area to be cooled, the thermostat device 21 will open valve 20 permitting the CO: gas to flow into container ll, thus buiidingup a, pressure over the liquid in said containerflland forcing the cooled refrigerant in space 5 into the cooling coil time'asthe gas gamete II. was checkva iv'ell inpipe it closes against ports 22, 22' are in register, when the gas in container I! will be exhausted and the liquid from tank I! will flow into container I8 causing the float "to rise and thereby actuate valve I! to rotate the latter back to a position placing ports 2|, ii in register and closing port 22. This action will be repeated as long as the thermostatic valve 2! is held open by the thermostat. In actual practice. the system will operate sat isfactorily at very low gas pressure. particularly where care is taken in the installation to keep the upwardly extending length of conduit I rela-- tively short. The application of gas pressure in container it direct to the body of the refrigerant. rather than by indirect transmittal of power to mechanical means. such as pistons, diaphragms, etc., eliminates the complications that are common to such means, and also enables cire culation of the liquid refrigerant under less gas pressure than is required where such means may be employed. With the use of such lowered pressure, objectionable carbonization of the liquid refrigerant isavoided, and the gas that is discharged from the system, other than may be discharged in the event of actuation of the pressure relief valve, is only that amount used periodically after each movement of the liquid refrigerant from container II to the cooling coil- Another advantage in my invention is the almost complete elimination of mechanical parts that might cause a failure in operation, which is a particularly important feature in cars, and

'the like, where servicing facilities arelimited,

but where a failure of operation would result in' heavy losses in products requiring a low temperature for preservation thereof.

Heretofore. efforts towards accomplishing the desired results of this invention have involved the use of motors. mechanical pumps. diaphragms, pistons or the like, and also attempts have been mad to cause movement of secondary liquid refrigerant by CO: gas by causing the gas to bubble through a column of such refrigerant for agitating the liquid to thepoint where it will be caused to overflow from the column on irregular splashes. This latter method is objectionable due to its low cooling efliciency and to the fact that carbonization of the liquid occurs to an undesirable degree and to the fact that the escape of gas is practically continuous, thus making for high operating costs.

In Fig. 8, I show, diagrammatically. a modified form of the invention, in which the liquid refrigerant is passed directly into the dry ice container, so that the latter forms part of the closed circuit for the liquid. No double bottom is used. The outlet conduit 1' from the bottom of tank I'- has a check valve 44 therein, which conduit leads to cooling coil II, and from It a con.. tinuation II thereof, extends directly into the top cf container II, which latter contains the valve elements identically as described with reference to the preferred form of the invention, except that valve 43 or the equivalent thereof, is omitted. From the foregoing, it is seen that the tank I! as shown in Fig. 1, is omitted.

From the container I' the gas inlet pipe 23' communicates between the upper portion of tank exhaust pipes 24' also communicates with said valveinthesamemannerasshowninl'ig. l and described in Piss. 8 to 'I. The outlet conduit i from the bottom of tank II communicates between tank I! and the bottom end of container I' at a point iustrabove the bottom of the container I, check valve 4! being,-in said pipe. In conduit I Just in advance of ,the cooling coil II, I provide a thermostatically actuated valve 28' adapted to be actuated by a thermostat device 21' for opening the line I to flow of liquid into the cooling coil upon a rise in temperature at device 21'.

In operation. assuming the liquid is all in the bottom of container I, and valve 10' is open. The gas in container I is not free to pass into container II through conduit 23', since port II is closed, hence the pressure on the liquid in container I' will force the same through conduit 1' into the cooling c011 II and from thence into container II, filling the container and causing the float therein to rise until float actuated valves are moved to close exhaust it and to open conduit 23' to flow of gas into container II, thus equalizing the gas pressure on the liquid in container II and in container I, thereby permitting the liquid in container II toflow by gravity into container I. This results in the float in container II falling and opening the exhaust port in container I8 and closing port II thereby restoring the elements to the position above described at the commencement of the operation. This cycle is then repeated as long as valve 28' is open, but is discontinued during the period when valve 2' is closed.

The dry ice 2' in the above container I is supported on a pan or tray 40 supported above the bottom of the container. as by legs 41 or in any.

I in the bottom of the container I, even when all of the refrigerant is therein, is preferably below the upper edges of the side of said pan II, and in operation the level is preferably always in a plane somewhere above the level of the bottom of the pan so as to maintain a constant heat transfer relationship between the dry ice and the liquid through the walls of the pan. Since the sides of the pan are spaced at one or more points or at all points thercaround from the side walls of the container, the gas pressure developed in the pan is always effective on the surface of the liquid refrigerant in the container I. In describing the pan walls as spaced from the sides of the container I to admit the gas pressure directly into the liquid refrigerant. it is to be understood that perforations may be provided in the pan sides or in a flange connecting between the upper edges of the pan sides and walls of the container, without invention, since the basic idea is to permit gas pressure in the container to be effective on the surface of the liquid refrigerant I and the valve mechanism in container II, and 76 in said container.

The advantage of the above construction is apparent when it is considered that in using a double bottom, the metal of the inner bottom must be very heavy to withstand the gas pressure, thus reducing the rate of transfer of heat from the liquid refrigerant to the dry ice. But it iatobeunderstoodthatthedeviceoflisJismtended for relatively low gas pressure to avoid objectionable carhonization of the liquid refrigerant, while the device oi Fig. 1 may be usedfor higher gas pressure.

'Ihe' pan is preferably imperforate below the maximum level of the liquid refrigerant in con-- tamer I, but may be made perforate if it is found desirable to obtain a lower temperature in the liquid refrigerant.

Having described my invention, I claim: 1. In a refrigeration system, a primary refrigerant composing a body of solid 60:, a container iniwhich said body is enclosed fitted with a hollow bottom having one of its vwalls disposed in heat exchange relationship with the said CO: and supporting the solid CO: thereon, an inlet and an outlet to the space between the walls forming said hollow bottom, a cooling coil. a first cohduit leading from said outlet to one end of said cooling coil and a second conduit leadin from the opposite end of said cooling coil to said inlet, said second conduit including a circulating control chamber, a gas pressure line communicating between said chamber and said container for conducting CO2 gas resulting from evaporavalve in said chamber arranged and adapted to .002, and supportlngthe cm co: th'ereon,- an F Y inlet and an outlet to the spacebetween the walls tion of said solid 00: to said chamber, a float valve in said chamber arranged and adapted to control the flow of said liquid through the chamber toward said inlet, and means including the 'gas pressure in said gas pressure line and the liquid in said chamber arranged and adapted to actuate said float valve for closing and opening said second conduit to flow of liquid to said inlet.

2. In a refrigerating system, a primary refrigerant comprising a body ofsolid CO2. a double walled container in which said body is enclosed including a passageway defined by the double walls of said container, one of which walls is disposed in direct heat exchange relationship with said body of CO1 for cooling, said passage way having an inlet and an outletior the liquid refrigerant. a closed conduit connecting the inlet and outlet, said conduit including a cooling coil and a circulating control chamber and a gas pressure line connecting said container with said chamber for conducting CO: gas from the container to the chamber, a rotary float-actuated said inlet? forming said hollow bottom, a cooiingcoii, a first I I conduit leading from said outlet to one end of said cooling coil and a second conduitincludinga storage tank for said liquid refrigerant. a cirj cuiating air tight chamber, a gaspressure line connecting said chamber with said container, a

rotary snap-acting valve in said chamber adapted to owillate for alternately connecting said chamber to the said gas pressure line and to the atmosphere at opposite ends of its oscillatory V movement, a float connected with said valve. and means including the gas pressure in said gas pressure line and the liquid in said chamber and said float arranged and adapted to actuate said valve for closing, and opening said'second condult to flow of liquid to said inlet.

4. In a refrigerating system, a primary refrigerant comprising a solid body 0! CO2, a container in which said body is enclosed including a passageway through the container with an inlet and an outlet thereto for the liquid refrigerant, a cooling coil, 9. first conduit leading from said outlet to one end of said cooling coil and a second conduit leading (mm the opposite end of said cooling coil to said inlet, including two chambers only. a gas pressure line communicating between one of said chambers and said container, a float valve in one of said chambers, and means including said liquid refrigerantand gas pressure in said gas pres-mire line foralternately opening said valve to said gas pressure line and to the atmosphere to cause ilow of the refrigerant to HARRYAQEBROWNQ, I

Images