US2292946A - Vapor cooling system - Google Patents

Description

Aug. 11, 1942. H. E. KARIG 2,292,945

VAPOR COOLiNG SYSTEM Filed Jan. 18, 1941 4 Sheets-Sheet l a l as HDIBEE Edmund Kariq mv NTOR A'ITORNEY Aug. 11, 1942. H. E. KARIG VAPOR COOLING SYSTEM Filgd Jan. 18, 1941. 4 Sheets-Sheet 2 Hnraca Edmund Kari INVENTOR ATTORNEY Aug. 11, 1942.

H. E. KARIG VAPOR COOLING SYSTEM Filed Jan. 18, 1941 4 Sheets-Sheet 5 Hnr'ana Edmund Kan lNV NTOR ATTORNEY Aug. 11, 1942. E. KARIG VAPOR COOLING SYSTEM Filed Jan. 18, 1941 4 Sheets-Sheet 4 .Aul

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ya: 2: Ll wu- Hnrana Edmund Kant ATTORNEY Patented Aug. 11, 1942 UNITED STATES PATENT OFFICE VAPOR COOLING SYSTEM Horace Edmund Karig, Rutherford, N. J.

Application January 18, 1941, Serial No. 374,979

17 Claims.

This invention relates to vapor cooling systems for internal combustion engines or other cooling systems where cooling temperatures desired are above the ambient air temperature or other cooling medium available.

An object of this invention is to provide uniformity of the cooling temperature in an engine cooling system, regardless of localized heating in that system.

Primarily the present invention is for the provision of a cooling system the fundamentals of which consist of evaporating a liquid in a sealed or closed system at any desired evaporation temperature by controlling the pressure corresponding to the desired temperature. The vapor evolved is then condensed in an auxiliary condenser cooled by air, water or other available cooling medium which is lower in temperature than the evaporation temperature.

An object of the present invention is to provide such a closed or sealed vapor cooling system, for airplane or other engines, which, will permit maintenance of a uniform cooling temperature for the engine regardless of variations in conditions to which the engine is subjected and providing considerable savings in weight over approved water or other liquid cooling systems wherein the liquid is not vaporized. These savings in weight are due, among other reasons, to the higher heat transfer rates of evaporating or condensing of liquids as compared to heating or cooling of liquids, and to higher mean effective temperature differences for evaporating and condensing systems as compared to heating or cooling of liquids. Therefore an effective system for providing the desired heat transfer will require less heat transfer surface in the condenser for the rejection of heat, as compared to a liquid cooling radiator.

A saving in weight is also effected because less weight of liquid or vapor is required, the improved cooling system being partially filled with vapor rather than being completely filled with liquid. Further, less circulation of liquid is required, as the heat removed by evaporating one pound of liquid is higher than that removed by raising the temperature of a liquid to any practical amount,

Depending upon the cooling temperatures and pressures desired in the cooling system, various fluids or coolants may be chosen to successfully operate in the system to provide low pressure during operation, that are non-explosive or noninflammable under any circumstances or conditions, and which have very low freezing points and negative co-efilcients of expansion if freezing does occur.

For aircraft engines or other internal combustion engines requiring coolant temperatures above 225 F. the present cooling system is particularly adaptable to use of a fluid technically known as tetrachlorethylene (CChzCCla) and known to the trade as Perchlorethylene. This liquid is a clear, colorless one with a high boiling point of approximately 249 F. at atmospheric pressure, is nonexplosive and non-inflammable, and is particularly adapted for use in a cooling system of the type embodied in the present invention and operating under the conditions met with in either military or commercial aviation. 1

Various fluids other than tetrachlorethylene may be used in the cooling system for operating above or below 225 F. at a pressure either above or below thesurrounding atmospheric pressure. Among such fluids are water, carbon tetrahcloride, ethylene dichloride, trichlorethylene, methylene chloride, monochlorobenzene or acetylene tetrachloride. Such fluids may be used as coolants when proper materials and inhibitors are used in the construction of the system, the choice depending upon the temperature and pressure range desired and the'conditions of service.

Another object of the present invention is to provide accurate temperature control of the cooling system, either automatically or manually, especially in aircraft cooling systems which are subject to wide changes in atmospheric pressure due to changes in altitude, and where wide changes in the cooling load occur due to increased or decreased engine power, it being desired to maintain a constant cooling temperature.

Another object of the present invention is to provide, in a closed or sealed cooling system, automatic means for removal of air or other noncondensible gases from such systems to prevent reduction of the heat transfer or operating efliciency of the system.

A further object of the invention is the provision of means for preventing the total disability of an engine in which it is embodied to operate for a continued period in case of leak or puncture in the cooling system, and especially for enabling military aircraft to continue in flight in case of puncture due to gun-fire or other cause.

The sealed cooling system of the present invention also lends itself to the use of two or more fluids, one of which, possessing a higher boiling point than the other, may circulate through the system as liquid without evaporating while the other fluid having the lower boiling point will provide the desired cooling by evaporation. By utilizing two fluids in the system, water may be used as the evaporating medium for removing heat from the-engine or cooling system by evaporation, and ethylene glycol, diethylene glycol, propolene glycol, triethylene glycol or an analogousfiuid, soluble in water, may be employed to prevent freezing of the water at low temperatures.

In applications where cooling temperatures lower than 212 F. are desired, when using water as the coolant, the present cooling system may be operated with a pressure therein below atmosphere to provide the necessary vaporization of the water at the desired operating pressure, by providing in the system suitable purge means for removing from the system any air or other noncondensible gases that may leak into the system, thereby permitting operation of the system to provide any desired cooling temperature through regulation of the pressure within the system.

Alcohol or other analogous liquids soluble in water and having a boiling point lower than that of water may be used as the coolant in association with the proper amount of water in the system, permitting operation of the system at predetermined pressures above the surrounding atmospheric pressure and allowing automatic purging of air and other non-condensible gases from the system without requiring the use of vacuum producing apparatus in the cooling system.

A still further object of the present invention is the provision for aircraft or other engines of a combined sealed vapor cooling system with an air cooling system, whereby the disadvantages of air cooling of engines will be overcome, uniformity of cooling temperature can be maintained through all parts of the engine, and considerable savings in size and weight of the condenser obtained.

Another object of the present invention is to provide, in a sealed vapor cooling system for internal combustion engines, means for controlling the circulation of the cooling medium through the condenser, whereby the pressure in the system may be controlled with corresponding control of the cooling temperature produced, and/or to provide thermal controlled pressure regulating means between the engine and the condenser for regulating the pressure in the cooling jacket of the engine providing corresponding control of the cooling temperature produced.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a vapor cooling system of the preferedform embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings a Figure 1 is a diagrammatic view, partly in section, of the improved cooling system.

Figure 2 is a vertical view in section, through a purge mechanism employed in the cooling system.

Figure 3 is a detail view in section, of a thermal actuated pressure controlling mechanism employed in the system.

Figure 4'is a detail view in section through a modified form of a pressure regulating thermal valve.

Figure 5 is a diagrammatic view, partly in section, of a modified form of the cooling system.

Figure 6 is a diagrammatic view, partly in section, of a modified form of the cooling system showing means for controlling the pressure in the system by control of the flow of cooling medium through the condenser.

Figure '7'is a diagrammatic view, partly in section, of a modified form of the cooling sys tem arranged to employ two liquids having different boiling points.

Figure 8 is a diagrammatic view of a modification of the system employing combined air and vapor cooling for the engine.

Referring more particularly to the-drawings, an internal combustion engine of any approved type, such as an aviation engine, is indicated at I, the cylinder or cylinders of which are surrounded by a cooling jacket 2, of ordinary approved construction. A surface condenser 3, of approved type, is connected in a closed system by means of suitable piping 4 and 5 with the cooling jacket 2 of-the engine I. The condenser 3 is of approved condenser construction of the surface type embodying a shell 6 and Ya plurality of tubes or passages 1 through which the cooling or condensing medium is circulated for condensing vapor in the condenser.

The entire system is sealed, to prevent leakage of air into the system or leakage of vapor therefrom. A liquid coolant of any approved type such as hereinabove referred to is placed in the system, the quantity of such liquid employed being only great enough to approximately fill the cooling jacket 2 of the engine l. The liquid coolant is taken from the lower portion of the condenser 3 through the pipe 4 by a circulating pump 8 and pumped into the cooling jacket 2, wherein it will be vaporized, dissipating the heat produced by the operation of the engine I to maintain the desired operating temperature of the engine, irrespective of the temperature of the surrounding atmosphere or the conditions under which the engine is operating. The vapor from the cooling jacket 2 passes through the pipe 5 and into the condenser 3, where it is condensed by the action of the cooling medium circulating through the tubes 1. The condensed coolant passes to the bottom of the condenser 3 and is again circulated through the cooling jacket for vaporization.

The condenser 3 has a pocket 9-therein, preferably at the top of the shell, for concentration and subsequent removal of air or other noncondensible gases from the system. The release or removal of the air or other non-condensible gases from the pocket 9, and consequently from the cooling system, is controlled by a pressure operated thermal controlled purge valve I, which latter is specifically illustrated in Figure 2 of the drawings and will be hereinafter more specifically described.

The desired temperature produced by the vaporization of the coolant is thermally controlled by regulation of the pressure in the cooling jacket, through the medium of a thermal controlled pressure actuated and regulating valve structure II. The valve structure II is shown in detailed section in Figure 3 of the drawings.

If conditions require it, that is; where' the cooling system is stationary, or if suflicient circulation of air is not occasioned by the movement of the vehicle to provide condensing action in the condenser 3, a fan, as shown at |2, may be provided for increasing the circulation of air through the condenser.

Referring specifically to the thermal controlled pressure actuated purging valve I9, this valve comprises a body I4, the interior of which is divided into an upper compartment l and a lower compartment It by means of a diaphragm H. The lower compartment |6, which is sealed against leakage, is connected through suitable piping or tubing |3 to a thermal bulb I9, which latter is placed within the interior of the condenser 3, as clearly shown in Figure 1 of the drawings. The thermal bulb I9 is of the usual approved type of thermal bulb, which maybe purchased upon the market, having therein a liquid which is subject to expansion and contraction on temperature variation, thus developing a pressure in the lower chamber |6 which cooperates with the spring 2| and diaphragm H to hold-the valve 22 seated against its valve seat 23, so long as the pressure within the upper chamber |5 is only equal to or below the pressure exerted upon the diaphragm I1 by the spring 2| and by the pressure developed by the thermal bulb IS. The upper chamber I6 is connected by suitable piping 24 to the purge pocket 9 in which the air and non-condensiblegases in the system collect. The valve 22 is connected to the diaphragm l1 for movement therewith and seats against the valve seat 23 formed in the outlet plug structure 25. The plug structure 25 is provided with a bore 26, which opens out through suitable openings 21, inwardly of the valve seat 23, into the chamber 25 which opens out to atmosphere through a suitable outlet opening 28. A spring seated valve 29 is interposed in the bore or passageway 26, and seats against a valve seat 30 therein, which is located between the valve seat 23 and the opening 28 to atmosphere. -When the pressure of air and/or other non-condens'ible gases in the purge pocket 9 and consequently in the upper chamber I5 rises above the predetermined pressure provided by the spring 2| and the pressure created by the thermal bulb IS, the

diaphragm will be depressed, opening the valve l9, which is acted upomby the temperature within the condenser 3, it will be seen that the bleeding ofi of the air and other non-condensible gases from the condenser, and consequently the pressure within the condenser, will be controlled by the temperature within the condenser.

As previously stated, the pressure within the coolingjacket 2 of the engine is regulated by the temperature therein, through the medium ofthe valve structure I shown in detail and in section in Figure 3 of the drawings. This valve mechanism comprises a valve disc 3|, which cooperates with a valve seat 32 formed in the piping connection 5 between the cooling jacket 2 and the condenser 3. The valve stem 33 is connected to the valve 3| and has its upper end connected to a disc 34, which latter is supported within the housing 35 by an expansible bellows 36, of approved type which may bepurchased upon the open market. The disc 34 is urged inwardly to compress the bellows 36 and seat the valve 3| condenser.

by means of a spring 31, the tension of which is regulated by an adjustable tension setting screw 36. The interior .of the bellows, or the space 40 between the inner and outer walls of the bellows, is sealed, and has communication through a suitable connection 4| with the interior of a thermal bulb 42, of approved construction. The thermal bulb 42 is placed within the cooling jacket 2 of the engine I so that the liquid within the bulb will be subjected to expansion and contraction by variations in the temperature produced within the cooling jacket 2.' The expansion and contraction of the liquid within the bulb 42 will cause a proportionate variation of the pressure in the chamber 49 of the bellows member 36. Thus the expansion and contraction of the bellows 36 with the consequent seating and unseating of the valve 3| will be controlled by the temperature within the cooling jacket 2. When the temperature rises within the cooling jacket, the valve 3| will be opened, permitting lowering of the pressure within the cooling jacket, and as the temperature within the cooling jacket 2 falls the valve 3| will be moved closer to or upon its valve seat 32, regulating the active orifice of communication between the cooling chamber or jacket 2 and the This regulates the pressure within the cooling jacket 2, which will in turn regulate the vaporization of the coolant therein and thereby regulate the temperature produced.

In Figure 4 of the drawings a simple, modified construction of the temperature actuated valve for controlling the pressure within the cooling jacket of the engine is illustrated. In this form an expansible bellows 44, of any approved type which may be purchased upon the open market, and which is susceptible to expansion and contraction by heat variations, is placed in the pipe connection 5' which leads from the engine to the condenser. idly connected either to the pipe 5' or to the shell of the engine I, while its outer end is connected to flexible valve elements 45, which are moved upon expansion and contraction of the bellows 44 to vary the size of the active orifice through which the vapor passes from the cooling jacket 2 into and through the pipe 5. Thus ,the pressure within the cooling jacket 2' will be controlled by the temperature produced therein.

In the form of the invention shown in Figure 1 of the drawings the condenser 3 and the engine l are arranged at such relative elevations or levels as to require a circulating pump 8, of any approved type, for maintaining delivery of the liquid coolant from the condenser 3 to the evaporating cooling jacket 2 of the engine However, in instances where it is possible to mount the condenser at a higher elevation than the cooling jacket of the engine, this circulating pump, with its entailed expense and weight, may be eliminated from, the system. Such an arrangement is illustrated diagrammatically in Figure 5 of the drawings.

In Figure 5 the engine I is placed at an elevation so that the highest point of the cooling jacket thereof is below the lowest point of the condenser 3, permitting the liquid coolant to flow through the pipe 4 into the cooling jacket 2 of the engine by gravity, while the vapor will flow through the pipe 5 from the top of the The bellows 44 has its inner end rigthe medium of the purge valve l", and the pressure and consequently the temperature produced in the cooling jacket 2* may be controlled by a thermal controlled valve structure of the type shown in either Figure 3 or Figure 4. a

In some instances it may be desirable to control the pressure in the system in accordance with the temperature produced in the cooling jacket by controlling the-flow of the cooling medium through the condenser, resulting in control of the pressure in the condenser and consequent control of the pressure in the system, which in turn controls vaporization of the coolant and the temperature produced.

In Figure 6 of the drawings a form of construction is shown for controlling the circulation of the cooling medium through the condenser. While this one form is illustrated and described herein, it is to be understood that any suitable type of mechanism or means for controlling the circulation of the cooling medium through the condenser may be provided without departing from the spirit of this invention, and

that such structure or structures are embraced within the invention in so far as they fall within the scope of the claims hereof.

In Figure 6 of the drawings the condenser 50 illustrated is of approved surface type construction, and the-cooling medium circulated therethrough is air. The coolant passes, as a liquid, from the condenser 50 to the cooling jacket 5| of the engine 52, while the vapor passes from the cooling jacket 5| back into the condenser 50, where itis condensed. The condenser 50 is purged by a purge valve 53 of the type shown in Figure 2 of the drawings, and hereinabove described. For controlling the pressure in the system and consequently the temperature produced therein, means are provided for controlling the circulation of the cooling medium through the condenser. This means is illustrated as a shutter structure 54 of approved type, including a plurality of pivotally mounted blades 55, which are moved either to open or closed position for controlling the quantity of air passing through the'tubes of the condenser. The shutter structure 54 is operated by means of a suitable operating rodf58 of approved construction, which rod is in turn operated through suitable mechanism by variations in temperature within the cooling jacket 5|; The mechanism for operating the rod 56 comprises a cylinder 51 in which a piston 58 is mounted for reciprocatory movement. The piston 58 is urged into shutter or damper operating movement in one direction by means of a spring 58, and in the opposite shutter operating direction by means of pressure fluid admitted to the cylinder 51', from any suitable source of pressure fluid (not shown), by means of a thermally controlled valve structure 60. The valve structure 60 is of any approved type which may be purchased upon the open market, and is operated by variations of pressure therein occasioned by temperature changes in the cooling jacket 5| of the engine 52 through the medium of a thermal bulb 6|, which is mounted in the cooling jacket 5| and connected to the valve 60 by suitable tubing 62. The thermal bulb 6| is of ,the same type as thermal bulb I9 hereinbefore described, and operates in the same manner. Thus, by means g 2,292,946 manner as in the form shown in Figure 1, throughv the condenser, regulation of the pressure therein,

and consequent regulation of the temperature produced in the cooling jacket 5|.

As referred to in the preamble to the specification, the present system lends itself readily to the use of two liquids, such liquids having different boiling points. The structure diagrammatically shown in Figure 7 of the drawings illustrates the system as applied for use of two such liquids. In this Figure 7 the engine 10 is provided with a cooling jacket H, which is connected by means of the pipe 12 to the condenser I3 so that the liquid vaporized in the cooling jacket II will pass, in vapor form, into the condenser 13, where it will be condensed and returned to the cooling jacket through the piping l4, employing a circulating pump 15, if such pump is necessary for maintaining the proper circulation. In this system illustrated a water-glycol solution, or water and another soluble liquid with a higher boiling point than water, is used as the coolant. A bleeder line 16 is connected from substantially a mid-point in the cooling jacket II where concentration of glycol in solution will be high, to the condenser 13. The bleeder line 16 will return a portion of the glycol back to the condenser 13, thereby increasing the glycol concentration in the water vapor being condensed in the condenser, increasing the glycol or non-freeze content of the liquid at the point or place where the liquid is at its lowest temperature. As in the other systems heretofore deof the temperature within the cooling jacket 5|,

scribed, this system shown in Figure '7 may be purged, and the pressure in the system regulated, in any of the manners and by any of the means described in connection with the other systems, already discussed.

It is desirable, particularly in aviation, to reduce the weight of the aircraft and its various parts as much as possible so as to increase the load carryin capacity of the craft. While provision of air cooled engines decreases the weight of the power plantto a greater degree than provision of a vapor phase cooled engine as described herein, straight air cooling of aircraft engines has many disadvantages, such as nonuniform cooling temperatures for all parts of the engine, complicated design problems, and localized overheating. In Figure 8 of the drawings a further modified form of the cooling system is illustrated combining air and vapor system cooling in such a way as to overcome the disadvantages of straight air cooling and to embody the numerous advantages of the vapor cooling system. By the combination of air and vapor cooling, uniformity of the cooling temperature and control of the temperature may be provided, with the elimination of localized overheating. Such combined structure will material reduce the weight of the vapor cooling system in that a smaller condenser and a smaller quantity of coolant will be required, since a considerable portion of the heat is removed directly through the radiating fins on the engine.

In this form illustrated in Figure 8, the engine is provided with radiating, air-cooled fins BI, and with a cooling jacket 82, so that part of the heat generated by operation of the engine will be dissipated to atmosphere through the fins 8|, thereby reducing the degree of heat transfer necessary through the vaporization of liquid in the cooling jacket -82. The vapor system employed in this modified form shown in Figure 8 may be'the same as any of those illustrated in the other figures and heretofore described, comprising a condenser 83, purged-by means of an densedand returned via piping 85 to the cooling jacket 82 for revaporization.

In the event that the sealed or closed vapor cooling system of any of the systems shown herein is punctured, by gun-fire or other causes, the system may be adjusted to maintain a pressure therein below atmosphere, preventing leakage of the coolant from the system and permitting the engine to operate for a continued period after the puncture.

From the foregoing description it will be apparent that the present system of cooling internal combustion engines has many advantages over conventional liquid cooling systems, one such advantage being the uniformity of cooling temperature throughout the system,regardless of localized heating or distribution of liquid in circulation, which advantage minimizes design problems in complicated engine structures and completely eliminates possibility of localized overheating. The heat transfer for evaporating or condensing liquids is higher than for cooling or heating liquids, which permits a considerable saving in heat transfer surfaces, especially in the condenser or radiator. Further saving in heat transfer surface is also possible due to higher mean effective temperature differences, as all of the condensing surfaces will be at the same condensing temperature. This is not the case in liquid cooling radiators, where the mean temperature varies because of the reduction of the liquid temperature as it passes through the radiator. As the latent heat of evaporation is considerably. higher than the possible heat removal by sensible heat of the liquid, only a fraction as much liquid circulation is required in a vapor cooling system of the type embodiedin the present invention as isrequired in conventional liquid cooling systems. This, combined with the saving in heat transfer surfaces, effects a considerable weight reduction of equipment, which is of particular advantage in aviation. Also, since the present system is a sealed or closed system, trouble and reduction of heat transfer efliciency due to scale or dirt clogging of the heat transfer surfaces is eliminated.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is: I

1. In a system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, and thermal controlled pressure actuated means for automatically purging said sealed cooling system of air and non-condensible gases.

2. In a vapor system for cooling internal combustion engines, the combination with an engine having acooling jacket; of a condenser connected in a sealed system with said jacket anda quantity of volatile coolant in said system" approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, and thermal controlled pressure actuated means for controlling the pressure in said cooling jacket to regulate the cooling temperature produced in the jacket.

3.;In a system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said. jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to bev vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, said condenser being of surface type having a cooling medium circulating therethrough for condensing the vapor, means for regulating the circulation of the cooling medium through the condenser for regulating the pressure in the system, and means operated by temperature produced in the cooling jacket for controlling operation of said circulating medium regulating means.

4. The method'of cooling an internal combustion engine where cooling temperatures are above the ambient air temperature which consists in circulating in a sealed cooling system a quantity of volatile coolant sufficient approximately only to fill the cooling jacket of the internal combustion engine, delivering the coolant in liquid form to the cooling jacket of the internal combustion engine, vaporizing the coolant in the cooling jacket, condensing the resultant vapor and returning the condensed coolant to the cooling jacket of the engine, and varying the pressure in the system by varying the flow of the cooling medium employed to condense the vapor whereby the vaporization temperature of the coolant may be varied as required.

5., The method of cooling an internal combustion engine where cooling temperatures are above the ambient air temperature which consists in circulating in a sealed cooling system a quantity of volatile coolant sufficient approximately only to fill the cooling jacket of the internal combustion engine, delivering the coolant in liquid form to the cooling jacket of the internal combustion engine, vaporizing the coolant in the cooling jacket, condensing the resultant vapor and returning the condensed coolant to the cooling jacket .of the engine, varying the pressure in the system by varying the flow of the cooling medium employed to condense the vapor whereby the vaporization temperature of the coolant may be varied as required, automatically purging the system of air and non-condensible gases, and

. controlling the purging of the system by tempergines which comprises circulating tetrachlorethylene in a sealed circuit including passing it through the cooling jacket of an internal combustion engine to cause vaporization of the tetrachlorethylene, condensing the resultant vapor, returning the condensate under pressure to the engine cooling jacket, and maintaining the cool- 9. In a vapor system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, and pressure actuated means operable only when the pressure of non-condensible gases in the system rises above the pressure corresponding to the condensing temperature of the coolant to purge the system of non-condensible gases.

10. In a vapor system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the coolingjacket in liquid form, pressure actuated means operable only when the pressure of non-condensible gases in the system rises above the pressure corresponding to the condensing temperature of the coolant to purge the system of non-condenslble gases, and means independent of said pressure actuated purging means for-automatically regulating the pressure within said sealed cooling system for regulating the temperature produced by the system.

11. In a vapor system for.cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a'quantity of volatile coolant in said system approxi mately equal in volume onlyto the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, a valve in the system between the condenser and the cooling jacket, tensioned means operable upon variances of temperature in the cooling jacket for operating said valve, and means for varying the tenslonvof said tensioned means for controlling the temperature produced in the system.

12. In a system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quanthe vapor, means for regulating the circulation of the cooling medium through the condenser for regulating the pressure in the system, saidcondenser provided with a pocket therein for the collection of air and non-condensible gases, pressure actuated means for permitting bleeding of air and non-condensiblegases from the pocket, and thermal means actuated by temperature in the sealed system for operating said pressure actuated means.

13. In a system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, said condenser being of the surface type embodying a plurality of passages for circulation therethrough of a cooling medium for condensing the vapor, means for regulating the circulation of collection of air and non-condensible gases, and

pressure actuated means operable only when the pressure of non-condensible gases in the system rises above the pressure corresponding to the condensing temperature of the coolant to purge the system of non-condensible gases.

14. The method of cooling an internal combustion engine where cooling temperatures are above the ambient air temperature which consists in circulating in a sealed cooling system a quantity of volatile coolant sufllcient approximately only to fill the cooling jacket of the internal combustion engine, delivering the coolant in liquid form to the cooling jacket of the internal combustion engine, vaporizing the coolant in the cooling jacket, cooling only the resultant vapor to condense it while retaining the nonvaporized volatile coolant in the cooling jacket of the engine, and returning the condensed coolant to the cooling jacket of the engine.

15. The method of cooling an internal combustion engine where cooling temperatures are above the ambient air temperature which consists in circulating in a sealed cooling system a quantity of volatile coolant sufllcient approximately only to fill the cooling jacket of the internal combustion engine, delivering the coolant in liquid-form to the cooling jacket of the internal combustion engine, vaporizing the coolant in the cooling jacket, cooling only the resultant vapor to condense it while retaining the nonvaporized volatile coolant in the cooling jacket of the engine, returning the condensed coolant to the cooling jacket of the engine, and purging the system of non-condensible gases only when bustion engine where cooling temperatures are above the ambient air temperature which consists in circulating in a sealed cooling system a a quantity of volatile coolant sufllcient approxi- 1 mately only to fill the cooling jacket of the intern-a1 combustion engine, delivering the coolant in liquid form to the cooling jacket of the internal combustion engine, vaporizing the coolant in thecooling jacket, cooling only the resultant vapor to condense it while retaining the nonvaporized volatile coolant in the cooling jacket of the engine, returning the condensed-coolant to the cooling jacket of the engine, purging the system of non-condensible gases only when the pressure of the non-condensible gases in the system rises above the pressure corresponding to the condensing temperature of the coolant, and varying the pressure in the system by varying the flow of the medium employed to condense the vapor whereby the vaporization temperature or the coolant may be varied as required.

17. In a vapor system for cooling internal combustion engines, the combination with an engine having a cooling jacket, of a condenser connected in a sealed system with said jacket and a quantity of volatile coolant in said system approximately equal in volume only to the capacity of the cooling jacket of the engine and adapted to be vaporized in the cooling jacket, said condenser condensing the vapor produced in the cooling jacket for return to the cooling jacket in liquid form, pressure actuated means operable only when the pressure of non-condensible gases in the system rises above the pressure corresponding to the condensing temperature of the coolant to purge the system of non-condensible gases, means independent of said pressure actuated purging means for automatically regulating the pressure within said sealed cooling system for regulating the temperature produced by the system, and means controlled by the temperature in the cooling jacket for regulating the circulation of the cooling medium through the condenser for regulating the pressure in the system.

HORACE EDMUND KARIG.

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