US2791107A - Manifold construction for heat exchange systems - Google Patents

Description

y 1957 H. MALKOFF ET AL 2,791,107

7 MANIFOLD CONSTRUCTION FOR HEAT EXCHANGE SYSTEMS Filed Oct. 26. 1950 INVENTORS.

United States Patent U is MANIFOLD CONSTRUCTION FOR HEAT EXCHANGE SYSTEMS Hyman Malkoff and Israel Kramer, Trenton, N. J., as-

signors to Kramer Trenton Company, Trenton, N. J., a corporation of New Jersey Application October 26, 1950, Serial No. 192,228

2 Claims. (Cl. 62-129) This invention relates to heat exchange systems or apparatus and, more particularly, to manifold construction for distributing refrigerant fluid to the several conduits or passes of an evaporator or the like; and has for an object to provide such a construction in which the distribution of the fluid is balanced so that each conduit or pass receives substantially the desired effective percentage thereof regardless of the position of the several conduits with respect to the inlet and outlet of the manifold or with respect to the side of the evaporator toward which the air current from the evaporator fan, or the like, moves.

Another object is to provide such a construction in which the distribution of refrigerant fluid to the several conduits or passes of the evaporator is so regulated that the conduit or pass nearest to the side of the evaporator toward which the current from the usual air circulating fan moves receives a larger amount of refrigerant than the other conduits or passes, which latter receive reduced amounts progressively according to their distance from the said side of the evaporator.

Another object is to provide such a construction which is adapted for embodiment in a refrigerating system without disturbing to any substantial extent the usual positioning and relative arrangement of the several elements or complicating the structure.

Another object is to provide such a construction which is adapted for effective functioning in connection with an heat exchange unit, such as an evaporator, that is fitted with two or any greater number of conduits or passes.

A further object is to provide certain improvements in the form, construction and arrangement of the several parts, whereby the above named and other objects inherent in the invention may be effectively attained.

Practical embodiments of the invention are represented in the accompanying drawing in which:

Fig. 1 represents a side elevation of the evaporator of a refrigerating apparatus, including the manifold construction of this invention;

Fig. 2 represents a section taken in the plane of the line 11-11 of Fig. 1, looking in the direction of the arrows;

Fig. 3 represents a view similar to Fig. 1, but showing a modified form of the invention; and

Fig. 4 represents a modification in which the manifold inlet is at the opposite end as compared with Fig. 1, and the distributors are arranged as in Fig. 3.

Heat exchange systems or apparatus commonly include units, such as the evaporator of refrigeration apparatus, to which a refrigerant in fluid form is conducted under pressure from a compressor and condenser, with or without a receiver, through an expansion valve, for the purpose of enabling the evaporator to perform its chilling or freezing function. In many systems or arrangements, the evaporator comprises a plurality of tubular conduits or passes which have their inlets and outlets Patented May 7, 1957 connected with manifolds. The manifold connected with the inlets of the conduits or passes usually has its own inlet at one end thereof and its side provided with openings or ports for making connection or communication with the inlet ends of the evaporator conduits or passes. Consequently, the refrigerant fluid enters the manifold while traveling in a direction substantially at right angles to the evaporator conduits or passes. We have found that the refrigerant fluid thus entering an end of the manifold under pressure fails to be evenly distributed to the several conduits or passes of the evaporator. There is a definite tendency for the fluid to travel or move in greater amount toward the closed end of the manifold opposite its inlet, with the result that the conduit or pass of the evaporator nearest the closed end of the manifold receives a greater amount of fluid than is received by the other conduits or passes. This effect or result is graduated so that the conduit or pass furthest from the inlet of the manifold receives the greatest amount of the fluid, the conduit or pass that is next distant from the manifold inlet receives the next greatest amount, and so on, with the conduit or pass closest the manifold inlet receiving the smallest amount. This gives rise to a condition in which only part of the evaporator operates at full efliciency, the conduits or passes which receive lower amounts of refrigerant fluid being handicapped or starved by lack thereof so that their effectiveness is diminished. A smaller undesirable condition arises when the fluid refrigerant is fed from the end of a manifold, rather than from its side, to a pair or greater number of the evaporator conduits or passes, from which latter the fluid enters a manifold for distribtuion to an additional pair or greater number of return conduits or passes,

This condition is aggravated by the fact that the usual fan which circulates air through the evaporator is commonly positioned at the side of the evaporator adjacent the manifold inlet and necessarily applies the greatest heat load to the conduit or pass of the evaporator that is nearest the fan, and progressively less load to the conduits or passes as they are spaced further and further from the fan; the result being that the conduits or passes needing the greatest amount of refrigerant to function efliciently receive progressively the least. The principle of this condition is not changed if the fan is positioned at the opposite side of the evaporator and draws air therethrough, because the greatest heat load is still applied to the conduit or pass nearest to the side of the evaporator toward which the air current moves and progressively less to the other conduits or passes.

The present invention is designed to eliminate the undesirable condition above described by insuring that each conduit or pass of the evaporator receives the refrigerant fluid in an amount commensurate with its heat load needs, so that its inner surface may be constantly wet with liquid refrigerant while the refrigerant emitted therefrom is in vapor form and at a slight super heat temperature of, for example, five to eight degrees Fahrenheit; this highly desirable result being obtained without the use of uniquely sized orifices, resistances or restrictors, but by utilizing the distribution of the energy of the motion of the refrigerant fluid within the manifold.

Turning now to the form of the invention shown in Fig. 1, an evaporator of any well known or approved form is denoted generally by 1 and it includes four individual conduits or passes marked 2, 3, 4, 5, which, as is usual,

take a sinuous form, as illustrated in Fig. 2. The outlets.

suction pipe 11 which leads to the intake of a compressor,

' 3 Or. the like, (not shown). The parts just described may be of conventional form and arrangement and they will not be further herein described as they constitute no part of the present invention.

The evaporator is also provided with a supply manifold 12, having an inlet 13 into which the refrigerant supply pipe 14 leads from the usual expansion valve that is in communication with the usual condenser or receiver. In one side of this manifold are formed four openings or ports into which are fitted four distributors which consist of tubes 15, 16, 17, 18, the other ends of the said distributors being connected with the conduits or passes 2, 3, 4, 5, respectively.

It will be observed that distributor 18, which is connected to manifold 12 at a point nearest to its inlet 13, leadsto conduit or pass 5, which is most distant of all the passes from said inlet 13; that distributor 17, which is next nearest to inlet 13, leads to conduit or pass 4, which is next distant from inlet 13; and that distributors 16 and 15, which are progressively further from inlet 13, lead to conduits or passes 3 and 2, which are progressively nearer to inlet 13.

The end of manifold 12 opposite to inlet 13 is closed so that refrigerant fluid entering the manifold through said inlet under pressure is forced into all the said conduits or passes 2, 3, 4, 5, in the operation of the refrigerating system or apparatus in which the evaporator 1 is used, as is well understood in this art.

As hereinabove explained, when the refrigerant is projected into the manifold 12 through its inlet 13, the greater amount of the fluid travels to and toward the closed end of the said manifold, with the ensuing disadvantage hereinabove explained arising in the case of previous manifold constructions in which the conduits or passes of the evaporator are connected seriatim with the manifold at points progressively further from the manifold inlet. However, the structure just described embodying the present invention is so arranged that the refrigerant which collects in greatest amount near the closed end of the manifold 12 is conducted through distributor 15 backwardly to conduit or pass 2, which is positioned nearest to the manifold inlet 13; that the distributor 16, which is next to distributor 15, conducts the refrigerant backwardly to conduit or pass 3; while distributor 17 conducts the refrigerant to conduit or pass 4; and distributor 18 conducts the re frigerant to conduit or pass 5. In other words, the connection between manifold 12 and the conduits or passes of the evaporator is such that the openings or ports in the side of the. manifold communicate in opposite sequence with the said conduits or passes according to their spacing from the manifold inlet, with the result that the fluid refrigerant contentof the manifold 12 is distributed to the conduits or passes of the evaporator in such a way that a greater amount of the refrigerant is supplied to each of the individual conduits or passes of the evaporator as their connections with the manifold are progressively nearer its inlet. This co-functions with the effect of the usual fan 19, which drives air through the evaporator, because the air current from'the fan is at its highest temperature when impinging upon conduit or pass 2, and is of progressively lower temperature as it reaches conduits 3, 4 and 5; so that the conduitsor passes bearing the greater heat loads are adequately fed with refrigerant while those bearing the lesser loads are not over fed, and the evaporator thus performs with increased efliciency and lack of evaporation or excessive evaporation are at least materially curtailed. As heretofore mentioned, the principle and effect are the same if the fan be placed at the opposite side of the evaporator and be rotated so as to draw an air current therethrough.

The total result of the foregoing is that the four individual conduits or passes of the evaporator will have refrigerant fluid distributed thereto in unequal amounts so related that all the said conduits or passes will function to satisfy with substantially equal effect the unequal heat loads applied thereto by the air current which becomes progressively cooler as it traverses the evaporator.

As indicated in the description of the figures of the drawing, Fig. 4 shows a modification in which a refrigerant supply pipe 20 connects with an inlet 21 at the end of the manifold 12 opposite to the inlet 13 shown in Figure l and hereinabove described. When inlet 21 is used, inlet 13 is, of course, omitted. With this form of manifold inlet it is not necessary to arrange the refrigerant distributors as shown in Fig. 1, because the fluid is injected into the manifold 12 in a direction opposite to the flow of the air current, and the greater amounts of refrigerant are automatically supplied to the distributors as they are positioned progressively nearer to the side of the evaporator toward which the air current moves. Hence, in this case the evaporator conduits or passes 2, 3, 4, 5, may be directly connected to the manifold in a sequence corresponding to the sequence of the said conduits or passes themselves. It should, however, be pointed out that design and/ or installation restrictions very often forbid the use of this arrangement for supplying the refrigerant through a pipe and inlet such as 20, 21; so that the distributor arrangement shown in Fig. 1 using the supply pipe and inlet 13, 14, is an important practical advance.

The modified form of the invention shown in Fig. 3 illustrates the invention as applied to a different type of distributor in which the refrigerant supply line, denoted by 22, consists of a tube, or the like, which is fitted at its end near the evaporator with a pair of distributors 23, 24, that communicate directly with conduits accumulate at the left hand end of manifold 29, as indicated by the arrow, and it will be observed that distributors 30, 31, are connected to conduits or passes 32, 33, in a sequence opposite to the direction of flow of the air current through the evaporator as denoted by the arrow and inscription, so that refrigerant is supplied to the said conduits in the desired unequal amounts for functioning in accordance with the principle of this invention.

in all forms of the invention the effect of the air current from the fan is substantially the same in that the air progressively decreases in temperature as it impinges upon the conduits or passes of the evaporator as they are spaced progressively more distant from the side of the evaporator toward which the air moves; and the advantageous functional effect or result of the invention may be summarized or epitomized by saying that it causes each conduit or pass of the evaporator tofunction with full, though unequal, effect in lowering the temperature of the air within the refrigerating chamber, or the like, in which the evaporator is positioned. It may be added that the distributors may be extensions of the conduits or passes themselves or be separate parts connected therewith.

We desire it to be understood that various changes may be resorted to in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, and hence we do not intend to be limited to the details herein shown or described except as they may be included in the claims or be required disclosures of the prior art.

' What we claim is:

l. A heat exchange unit, such as a refrigerant evaporator, comprising, a plurality of refrigerant conduits arranged in side by side relationship, means for passing an air current toand through said unit in contact with the outer surfaces of said conduits and in such a direction that 5 it impinges upon said conduits seriatim, a manifold for supplying refrigerant fluid to the interior of said conduits positioned so as to lie across the inlet ends thereof, means connected to the end of the manifold toward which the air current moves for feeding refrigerant thereto, the opposite end of the manifold being closed and a side of the manifold being provided with a series of openings extending between the two ends thereof, said openings being connected with the conduits in the reverse order of position of the openings and conduits,

2. A heat exchange unit, such as a refrigerant evaporator, comprising, a plurality of sinuous refrigerant conduits arranged in spaced substantially parallel planes, means for passing an air current to and through said unit in contact with the outer surfaces of said conduits and moving in a direction substantially normal to the plane thereof, an elongated manifold for supplying refrigerant to the interior of said conduits lying across their inlet ends in a direction substantially normal to the planes of the conduits, means for feeding refrigerant to the end of the manifold toward which the air current moves, the other end of the manifold being closed and the side of 6 the manifold being provided with a longitudinal series of openings, the opening nearest the closed end of the manifold being connected with the inlet of the conduit nearest the side of the unit toward which the air current moves, and the opening nearest the end of the manifold to which refrigerant is fed being connected with the inlet of the conduit that is furthest from the side of the unit toward which the air current moves.

References Cited in the file of this patent UNITED STATES PATENTS 2,041,443 Sundbac'h -May 19, 1936 2,054,404 Askin Sept. 15, 1 936 2,158,792 Erbach -a May 16, 1939 2,163,591 Deverall June 29, 1939 2,165,004 Peters July 4, 1939 2,171,407 Shrode Aug. 29, 1939 2,249,856 Rufi July 22, 1941 2,288,003 Kleucker June 30, 1942 FOREIGN PATENTS 452,765 Great Britain Aug. 17, 1936

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