US2836965A

US2836965A - Heat exchangers for vaporizing liquid refrigerant

Info

Publication number: US2836965A
Application number: US492435A
Authority: US
Inventors: Herman W Kleist
Original assignee: Dole Refrigerating Co
Current assignee: Dole Refrigerating Co
Priority date: 1955-03-07
Filing date: 1955-03-07
Publication date: 1958-06-03
Anticipated expiration: 1975-06-03

Description

H. W. KLEIST HEAT EXCHANGERS FOR VAPORIZING LIQUID REFRIGERANT June 3, 1958 Filed March 7, 1955 United States Patent HEAT EXCHANGERS FOR VAPORIZING LIQUID REFRIGERANT Herman W. Kleist, Hollywood, Ill., assigner to Dole Refrigerating Company, Chicago, lll., a corporation of Illinois Application lvlarch 7, 1955, Serial No. 492,435

7 Claims. (Cl. 62.-3)

My invention relates to an improvement in refrigerating means, and has for one purpose to provide improved means for controlling the iiow of volatile refrigerant from or to a compressor.

Another purpose is to provide means for controlling the temperature of the refrigerant as supplied to the condenser from the compressor.

Another purpose is to provide control means for controlling the flow of refrigerant from the compressor to the condenser and receiver which render valving or restriction of ow unnecessary.

Another purpose is to provide means effective to compensate for variation in outside ambient temperature, when a flow of volatile refrigerant is subjected to such variations.

Other purposes will appear from time to time in the course of the specification and claims.

The present application is a continuation-in-part of my copending application Serial No. 443,759, filed in the United States Patent Office on July 16, 1954, now Patent No. 2,775,683 of Dec. 2, 1956, for Heat Exchangers for Vaporizing Liquid Refrigeran I illustrate my invention more or less diagrammatically in the accompanying drawings wherein:

Figure l is a diagrammatic illustration of an embodiment of my invention;

Figure 2 is an axial section through a heat exchanger indicated in Figure l; and

Figure 3 is a section on the slide 3--3 of Figure 2.

Like parts are indicated by like symbols throughout the specication and drawings.

Referring to the drawings, 1 generally indicates a compressor in a refrigerating cycle in which, for example, a volatile refrigerant is employed. 2 indicates a suction return pipe extending from any suitable evaporator or evaporators, not herein shown, to the suction or inlet side of the compressor 1. 3 indicates any suitable condenser connected by a pipe 4 to any suitable receiver 5. 6 indicates a duct or pipe from the discharge or pressure side of the compressor 1 to the intake of the condenser 3. A indicates a heat exchange unit in the pipe 6 which will later be described in detail. 7 indicates a delivery pipe extending to any suitable evaporator or evaporators, not shown.

It will be understood that, as an example of my invention, I have illustrated part of a conventional refrigerating cycle in which a volatile refrigerant is delivered as a hot gas from the pressure side of a compressor, such as the compressor 1, is condensed to a hot liquid, still under pressure, in any suitable condensing means, such as my condenser 3, and is thereafter delivered, under pressure, as a liquid, along any suitable delivery line to whatever evaporating means are employed. The volatile refrigerant is evaporated in the evaporator in response to a drop in pressure, which may be obtained in any suitable way, or by any suitable means, not herein shown and not of itself forming part of my invention. I illustrate my invention as applied to the problem of controlling the temperature of a volatile refrigerant as it is delivered by a compressor to a condenser and receiver. Where the refrigerator, or any part of the refrigerating cycle, is subjected to outside, unheated air, the variations in the outside or ambient temperature create problems. For example, the minimum outdoors ambient temperature in parts of the United States may vary as much as F. or more from the maximuml outside ambient temperature. Such a iluctuation of temperature, or even a smaller liuctuation, creates problems affecting the flow of the hot gas from the compressor to the condenser. In the past, attempts have been made to control the resultant pressure iluctuations by valving or restricting the flow of hot gas from the compressor to the condenser. Any such valving or restricting presents practical problems, and has disadvantages into which I need not go in detail.

By my invention, I maintain regulation of ow by keeping the refrigerant at a generally constant temperature,l

regardless of changes in ambient temperature. I may do this by maintaining adequate heat exchange means in the line of ow of the refrigerant from the compressor to the condenser and by thermostatically controlling such means. As an example of such means I illustrate the unit A in Figure 1, which is shown in greater detail in Figures 2 and 3. In the form shown in Figure 2, I illustrate a heat exchange casing, in the form of an outer shell or cylinder Titi, having

end closures

11 and 12. The duct 6 delivers refrigerant, as at 6a, through the end 11 of the cylinder 1t), and the refrigerant is constrained to a tortuous and extended path, for example, by the spiral or helical vane 13. Refrigerant, after passing through the elongated passage thus formed, escapes, as at 6b, and ows toward the condenser.

While l do not wish to limit myself to any specic heat exchange means, except so far as I limit myself by specic limitations in my claims, I illustrate in Figure 2 an inner axial passage or pipe 14 which extends through the center of the helix 13 and which contains any suitable 'resistance heater 15 connected by suitable conductive connections 15a and 15b to any suitable source of commerical current. The heater 15 may be controlled in its operation by any suitable heat responsive control means 16, shown in Figure 2 as extending into any suitable pipe 16a extending through the end 11 of the cylinder and through several of the bends of the helix. .Thus the operation of the heater 15 may be controlled by a suitable heat responsive element, which, in turn, responds to the temperature of the refrigerant adjacent its entry into the tortuous passage. formed by the helix 13. Any suitable outside layer of insulation may be employed, as at 17.

It will be realized that, whereas, I have described and illustrated a practical and operative device, nevertheless many changes may be made 'in the size, shape, number and disposition of parts without departing from the spirit of my invention. -I therefore wish my description and drawings to be `taken as in a broad sense illustrative or diagrammatic. For example, whereas I iind the hea-t exchange unit shown to be highly advantageous, I may obtain my result `by other heat exchange means. What is essential is that I provide means for heating the refrigerant, when necessary, as it is delivered from the compressor to the condenser. By controlling this heating elect in relation to or in response to variations in ambient temperature, `I maintain Ian adequate uniformity of pressure conditions, and render `it unnecessary to valve or lto restrict the flow Vof 'the refrigerant to the condenser and to the receiver. Whereas the nature and position of the Vresistance 16 is `adequate and practical, it will be realized that 'I may employ heat responsive means subjected to the movement of the refrigerant at any point bient temperature, I may, if I Wish, employ heat respon-V sive means directly subjected to variation inV outside ambient temperature. YIn'na broad sense,H my `invention contemplates varying l:the heat deliveryl in'relation to or in director indirectresponse t-o changes-in outside ambient` temperature. Looking at the problem from `a somewhat different angle, I may say that the function ofthehat exchanger A in theY circuit, as shown in Figurel", is rather' to' prevent heatl'oss than to add heat, or

to'sfu'perheat. The problem 'solved by my invention is not thatof`at`fecting'jcondenser pressure but, rather, that of preventingvariatons in ambient 'temperature from yale'cting condenser pressure.V heat' exchanger A, con'- trolledi'n response to variations in `ambient temperature, adds temperaturewlien necessary to prevent an' unfavorable drop inicondense'r pressure. Whereas I have illustrated my invention as applied to control lthe flow of refrigerant from the discharge side of the compressorV Vto the condenser, it will be understood that I may employ Vmy invention atk other points, where necessary, in the passes from compressor tocondenser, in controlled relan tion to Variations of 'such ambient temperature.

2. The method of maintaining predetermined gas pressure in a refrigerating circuit, which includes heating the refrigerant, 'as it passes from compressor to condenser,

and varying `such heat input to the refrigerant, in response.

. 4 sure discharge pipe extending `from the compressor to the condenser, a pipe extending from ythe condenser to the evaporator and a return pipe extending from the evaporator to the suction side ofthe compressor, Iand'V means for maintaining the temperature of the hot Agas delivered from the compressor to the -condenser within a predetermined range, including heating means, and means `for maintaining said heating means in he'at exchange relationship with the 'hot gas flowing from the compressor tothe condenser. I

5. The structure of claim 4 characterized by and including `a lcontrol element responsive to vthe temperature of hot gas.

6. The structure of claim 4 characterized by `and including a tortuous passagermeans through which the hot gas Hows on its way yfrom the compressor to vthe condenser, heating means eective to deliver heat -to the gas as i-t ows through the tortuous passage means, and heatresponsive means for controlling the operation of the heating means, said heating-responsive means being adapted to respond `to the temperatureof the hot gasV owing through the tortuous passage.v

7. A method of operating `a mechanical refrigerating clrcurt including Ia compressor, la condenser and anevaporator, in surroundings subjected to substantial variationsV in `ambient temperature which includes sensing ambient `temperature and supplying heat when needed, in controlled response to lsaid sensing, tothe refrigerant Yas it passes from compressor to condenser, effec-tive to maintain a substantially uniform condenser pressure, `and thereby preventing undesired condenser pressure drops which might otherwise he caused by undue reduction ofY the ambient `temperature to Which the refrigerating sys-V tem is subjected. f

References Cited in the le of this patent UNITED STATES PATENTS La Porte June 16, 1953:V