US2289879A - Heat transfer system - Google Patents

Description

July 14, 1942. M. E. FIENE HEATTRANSFER SYSTEM Filed Dec. 20, 1940 inwaeamauaa Inventor" Marcus El. Fiene,

b-y is Attorney.

ing and condensing elements having improved lensing columns i2 with open air circulation between the vaporizing and condensing elements. nation of heat from the radiator to the surr temperature condition constant. I v v It is a further inject of my invention to pronormal to the radiator and to return condensate "lating the flow ohheat from a source toa dlssllo a separate conduit may he provided for convalves, bailles or the like, and which may be radiator.

. tion will becomevapparent as the following de-- 20 with ive St m from so rc n t Shown- The or the like. The amount of heat supplied to the as shown, o a sis in i ri u ion. f t e v p r facesQ Variation in the amount of circulating as heat transfer fluid in circulation in afluid cirervoir or receptacle and a condensate trap which cated in the bottom W l fo radiator Ill. The

arcane ms mausrnn srsrniu Marcus E, Fiona, Caldwell, is. a2, m it to Gen-- raikEiectrie Company, a corporation oif'New or Application December to, rein, No. errors 9 I won. car- 2 My invention relates to the transfer of heat. medium, the temperature of which is to be conparticulariy by vaporization and condensation I trolled, confined within space indicated by the of fluid. dotted lines ii, The radiator it may he formed It is an object of my invention to provide a of suitably pressed metal plates welded together heat music: system comprising fluid vaporizs to form a series of interconnected vapor conmeans for controlling the rate of heat transfer passages i3 therebetween to facilitate the dissi- It is number object of my invention to pro-- rounding unedium. A vaporizer i4 is located bevide an improved system for controlling the 10 low theradiator i0 and is connected thereto by transfer of heat to maintain a predetermined means of a conduit to which functions to conpating body without any moving parts such as u ting the vapor from the vaporizer t the readily controlled by a thermostatic mechanism. The vaporizeris heated by suitable means which Further objects and advantages 01 my invenmay ees llus rat d. a steam nine it sup ied scription proceeds, and the features of novelty steam pipe It extends th sh th V p riz r in out with particularity in the claims annexed t clined slightly to assist in the return of the steam and forming a part of this specincation.- v condensate to the source of suppl h usual Briefly. in carrying out the present invenas air vent i1 is provided to assist in eliminating tion in its preferred form, a circulating heat the noncondensable gases from the steam sys-i transfer system having a fluid vaporizing surtem. Preferably the vaporizer is covered with face and a condensing surface in fiuid circulata uitable nsula n o eas n ma e ial t o ing relation is connectedto receive heat from prevent undue loss of heat therefromto the a suitable source such as a steam supply main so surroun'm ii m midis also i y in lined,

dcindenslng' surface is varied by varying the condensate over the heat transfer surface of the amount of heat transfer fluid circulating be- Vaporizerheat transfer fluid, and consequently the rate cult comprising the interconnected vaporizer I4 device which eflects an exchange of h t t 40 receptacle to is connected by means of a siphon I is located in the path of thecondensate returntt m wall of the radiator III is preferably ining from the condensing surface to the vaporizer. (lined 80 that s e, n ing to the My invention 111 be better understood from. 45 vaporizer M. will readily flow int the trap 2| Fig. 1 is a magi-ammati'c representation trap 28 so that condensate collecting in the trap embodiment of my invention and Fig. 2 is a-modwill flow into the receptacle by ravity. ification of the arrangement shown in Fig. 1. 60 To cause the condensate to return from the For the purpose of illustrating a specific em receptacle 20 to the trap 2| and the vapo ze bodiment or my invention Ihave shown in Fig. I a hermostatically controlled heating device 1 of the drawing a thermostatically controlled is locatedin heat exchange relation with the vapor heat transfer system comprising a confluid in leg 22a of the siphon tube for effecting denser or radiator it for supplying heat to a o a thermo-siphon pumping action In the illus- 22a upwardly into overflows into the conduit i and passes down- H and the radiator pumped upwardly the contacts of the trated embodiment of my invention the heating device comprises an-electrical heater 26 energized from a suitable source such as the secondary winding 29 of a step-down transformer 30. A block of heat conducting material 21 may be mounted on the siphon leg 22a for concentrating the flow of heat from the heater 26 to the siphon leg. The energization of the heater 26 is controlled by the contacts 3| of a thermostat 32 located in the space H. When the heater 26 is energized it locally heats the fluid in leg 22a of the siphon 22 causing partial vaporization thereof so that the density of the fluid in leg 22a is less than that in the other siphon leg 22b whereby a differential of hydrostatic pressure is produced which forces the fluid in leg the trap 2| from which it wardly to the vaporizer I4. This thermo-siphon pumping-or percolating action produced by the heater 26 is very similar to the action of a percolating coffee pot.

To permit the free flow of condensate into and out of the chamber 20 through the siphon tube 22 a pressure equalizing venting tube 24 is provided which connects the upper portion of re'ceptacle 20 to the radiator ID. The tube 24 acts to equalize the vapor pressures in the receptacle and the fluid circuit comprising the interconnected vaporizer and radiator.

The vapor condensing radiator II), the vaporthe condensate izer H, the interconnecting conduit l5, the venting pipe 21, the receptacle 2|] and the siphon tube 22 are preferably all joined together and hermetically sealed by welding or brazing so that a closed vapor tight heat transfer system is obtained. This entire system is then evacuated of substantially all non-condensable gases through a suitable evacuating connection 25. Thereafter a predetermined charge of suitable vaporizable liquid such as water, alcohol or the like, is introduced into the closed system. The amount of this liqu d charge is such as to insure that the entire effective heat transfer surface of the vaporizer may be effectively wetted under maximum heat transfer conditions.

In operation, let heat transfer fluid 23 is collected in the receptacle and the siphon tube 22. as illustrated in the drawing, with n the enclosure in the open position. Since there transfer fluid circulating between the vaporizer III the rate of heat transfer therebetween will be substantially zero. If now the temperature of the medium within the enclosure falls below a predetermined value, which is determined by the setting of the thermostat 32, the contacts 3| close, the electric heater. is energized and condensate is forcedupwardly' in me leg 22a by thermo-siphon action into the condensate trapv 2 I the radiator l0 where it condenses giving up its latent heat of vaporization; The condensed heat transfer fluid then immediately returns to the vaporizer, the trap 2| being rendered ineffective since it is filled with condensate which is being from the receptacle. While thermostat-32 remain closed it be assumed that all of the that the temperature of the, medium II is at the desired value, and that the contacts 3| of the thermostat 32 are is no heat After thecondensate trap has become filled, the condensate spills over. into i more and more heat transfer fluid is pumped from the receptacle 28 into the system where it continuously circulates between the vaporizer and condenser. Thus the heat supplied by the radiator ||I- to the medium within the space H gradually increases until the temperature of the space reaches the predetermined value at which the thermostat contacts open causing deenergization of the electric heater 26 and a cessation of the thermo-siphon pumping action. The heat transfer fluid in circulation between the condenser and the vaporizer then gradually collects in the trap 2| and is returned to the receptacle 20 by gravity causing the heat supplied by the radiator to gradually decrease. This action continues until all of has been returned to receptacle 2|! or until the thermostat contacts close to restart the heat increasing cycle. Thus it will be apparent that the amount of heat transfer fluid in circulation between the vaporizer and condenser, and consequently'the rate heat is supplied by the radiator, is either increased or decreased depending on the position. of the thermostat contacts with the result that the average heat supplied by the radiator is automatically varied to maintain the temperature of the medium in space H constant.

In Fig. 2 of the drawing I have shown a modification -in which the transfer fluid by gravity and by thermo-siphon action between the condensate trap 2| and the receptacle 20 are the reverse of the arrangement illustrated in Fig. 1. In this modification the receptacle 20 is located slightly above the condensate trap 2| so that the heat transfer fluid will flow from the receptacle to the trap by gravity. In order to cause the heat transfer fluid to return from the condensate thermostatically controlled electric heater 26 is located in heat exchange relation with the leg 22b of the siphon 22.

In operation when the temperature of the medium within the enclosure H is above a predetermined value'the contacts 3| of the thermostat 32 are closed, asshown, and the heat transfer fluid is pumped by thermo-siphon action from the trap 2| to the receptacle 2|!v to decrease the rate of heat transfer between the vaporizer and the condenser. However, when the temperature of the medium within the space falls below the predetermined value the contacts 3| open deenergizing heater 26 and permitting the heat transfer fluid toflow by gravity from the receptacle 20 to the trap2| whereby the amount of heat transfer fluid in circulation and the rate between the vaporizer and condenser is increased. It will-be seen from the above description of my invention, a vapor heat transfer system has been provided which is entirely free from moving control elements such as valves, baiiles etc. This is an important advantage in a sealed and evacuated system since moving control elements wear qand generally require seals or pack -i of some sort which are apt to leak and destroy the vacuum in the system thus rendering it inoperable.

Furthermore, my control system is very economical to operate since only a very small amount of energy is required to operate the thermo-siphon pumping apparatus, the liquid head against which the pump operates being very small. 'Another control energy saving feature is the fact the thermo-siphon pumping apparatus the amount of heat transbetween the condenser and acts only to change fer fluid circulating.

directions of flow of'heat trap to the receptacle, the

of heat transferv vaporizer as distinguished from systems in which all of the circulating heat transfer'fluid passes through the pumping apparatus to complete the vaporizing and condensing cycle. 1

While I have shown and described particular ed vaporizer and condenser by alternate evaporation and condensation of said fluid, a condensate accumulating receptacle, means for effecting an exchange of heatvtransfer fluid between said receptacle and said circuitto vary the rate of heat transfer between said condenser and said vaporizer,-said means comprising a condensate trap located in path of condensate retuming from said condenser t said vaporizer, said trap being effective to divert heat transfer fluid .from said circuit when fluid collected in said trap is withdrawn and effective to add fluid to said circuit when fluid supplied to said trap overflows, a siphon tube having one leg connected to the lower portion of said receptacle and the other leg connected to said condensate trap, said receptacle being located below said tra and-vented to said circuit so that heat transfer fluid collecting in said trap will flow intosaid receptacle through said siphon tube by gravity; and means for local- 1y heating the fluid in the'leg of the siphon tube that is connected to said trap for causing heat transfer fluid to return from said receptacle to said trap by thermo-siphon action.

2. In a vapor heat transfer system of the type in which .heat transfer fluid is circulated in a closed fluid circuit comprising aninterconnected vaporizer and condenser by alternate evapora-' tion and condensation of said fluid, a condensate accumulating "receptacle, -means comprising a pump for effecting an exchange of heat transfer fluid between said circuit and said receptacle to change the amount of heat transfer fluid in cir- 'culation and the rate of heat transfer between said vaporizer and said condenser, andmeans for controlling said pump to vary said rate of heat transfer.

3. In a vapor heat transfer system of the type in which a heat transfer fluid is circulated in a closed circuit comprising an interconnected vaporizer and condenser by alternate evaporation and condensation of said fluid, a condensate ac-" cumulating receptacle, a conduit interconnecting said receptacle and said circuit, means for diverting heat transfer fluid from said circuit through desire to secure by accumulating receptacle, mean for effecting an exchange of heat transfer fluid between said receptacle and said circuit to vary the rate of heat transfer between said condenser and said vaporizer, said means comprising a condensate trap located in the path of condensate returning from said condenser to said vaporizer, said trap being effective to divert heat transfer fluid from said circuit when fluid collected in said trap i withdrawn and effective to add fluid to saidcircuit when fluid supplied to said trap overflows, a pump forpumplng heat transfer fluid in one direction through a conduit interconnecting said trap and said receptacle, said receptacle and said I conduit being located relative to said trap so that fluid flows in the opposite direction through said conduit by gravity when said pump is not in operation, and means for controlling the operation of said pump whereby an exchange of heat transfer fluid in either direction between said circuit and said receptacle may be effected.

transfer'fluid in either direction between saidsaid conduit'into saidreceptacle to decrease the amount of fluid'circulating between said condenser and said vaporizer, pumping means for returning the fluid from said receptacle to said circuit through said conduit to increase the fluid circulated between said condenser and vaporizer,

and means for controlling said pumping means whereby the amount of fluid circulating and the rate of heat transfer between said condenser and said vaporizer may be varied.

4. In a vapor heat transfer system of the type in which heattransfer fluid is circulated in a closed fluid circuit comprising an interconnected 5. In a vapor heat transfer system of thetype in which heat transfer fluid is circulated in a closed fluid circuit, comprising an interconnected vaporizer and condenser by alternate evaporation and condensation, of said fluid, a'condensate accumulating receptacle, means for effecting an exchange of heat transfer fluid between said receptacleand said circuit to vary the rate of heat transfer between said condenser and said vaporizer, said means comprising a condensate trap located in the path of condensate returning from said condenser to said vaporizer,

said trap being .eifective to divert heat transfer fluid from said circuit when fluid collected in said trap is withdrawn and eifectiveto add fluid to said circuit when fluid supplied to said trap overflows, a siphon tube having one leg connected to said receptacle and the other leg connected to saidtrap, venting means interconnecting said receptacle and said circuit for equalizing the vapor pressures therebetween, said receptacle and said tube being located relative to said trap so that fluid flows through said tube in one direction by gravity, means for locally heating the fluid in one of the legs ofsaid tube to cause fluid to flowthrough said tube in the opposite direction by thermo-siphon action, and means for controlling said heating means whereby an exchange of heat circuit and said receptacle may be effected.

6. In a system for transferring heat from a heat source to a medium the temperature of which is to be controlled by a vapor heat transfer means of the type in which heat transfer fluid is circulated in a closed fluid circuit comprising an interconnected vaporizer and condenser by alternate evaporation and condensation of said fluid, a condensate accumulating receptacle,

means comprising a pump for effecting an exchange of heat transfer fluid between'said circuit and said receptacle to change the amount of heat transfer fluid in circulation and the rate of heat transfer between said vaporizer and said condenser, and meansresponsive to the temperature of said medium to vary said rate of heat transfer.

7. In a system for transferring heat from a heat source to a medium the temperature of which is to be controlled by vapor heat transfer means of the type in which heat transfer fluid is circulated in a closed fluid circuit comprising an interconnected vaporizer and condenser by L if a vaporizer and condenser by alternate evapora tion and condensation of said fluid, a condensate for controlling said pump lected in said trap is heating the fluid 4 alternate evaporation and condensation of said fluid, a, condensate accumulating receptacle, a condensate trap located in the path of condensate returning from said condenser to said vaporizer, said trap being effective to divert heat transfer fluid from said circuit when fluid colwithdrawn and efiective to add fluid to said circuit when fluid supplied to said trap overflows, a siphon tube having one leg connected to said receptacle and the other leg connected to said trap, venting means interconnecting said receptacle and said circuit for equalizing the vapor pressures therebetween, said said tube being located relative that fluid flows through said tube in one direction by gravity, means for locally in one of the legs of said tube flow through said tube in the receptacle and to said trap so to cause fluid to opposite direction by thermo-siphon action, and

means for controlling said heating means to vary the amount of and the rate of heat transfer between said condenser and said vaporizer in accordance with the temperature of said medium.

8. In a vapor heat transfer system of the type heat transfer fluid in circulation in which heat transfer fluid is circulated in a closed fluid circuit comprising an interconnected vaporizer and condenser by alternate evaporization and condensation of said fluid, a condensate accumulating receptacle, a siphon tube interconnecting said receptacle and said circuit, and

means for applying heat to one of the legs of said siphon tube to .efiect an exchange of heat transfer ,fluid between said receptacle and said circuit by thermo-siphon action.

9. In a vapor heat transfer system, a vaporizer, a condenser, means for circulating heat transfer fluid in a closed fluid circuit' including said vaporizer and said condenser, a condensate accu mulating receptacle, means for effecting an exchange of heat transfer fluid between-said re-- ceptacle and said circuit to change the amount of heat transfer fluid circulating between said vaporizer and said condenser, said last-mentioned means comprising a siphon tube interconnecting said receptacle and said circuit, and a heater located in heat exchange relation with one of the legs of said siphon tube for effecting a thermo-siphon action.

- MARCUS E; FIENE.

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