US2008255A - Counter flow air conditioner - Google Patents

Description

July 16, 1935. L. u. LARKIN 2,008,255

COUNTER FLOW AIR CONDITIONER Filed Nov. 1e, 193s 2 sheets-sheet 1 ,/f C. MTP DVA H Mnjnwqldww@ A@ @N S Q. mm Q@ s @Mfma'gsfmwm drm c LA July 16, 1935. L, u. L ARKIN COUNTER FLOW AIR CONDITIONER Filed Nov. 16, 1935 2 Sheets-Sheet 2 w mi LESTER LAreK/N 5f www? Patented July 16, 1935 PATENT oFFlcE COUNTER FLOW CONDITIONER Lester U. Larkin, Atlanta, Ga., assignor to Larkin Refrigerating Corporation, Atlanta, Ga., a corporation of Georgia Application November 16, 1933, Serial No. 698,291

2 Claims'.

This invention relates generally to Ventilating air cooling systems; and, more particularly tov cooling systems adapted for use in the form of small compact highly efcient units for cooling air in refrigerated display counters or cases, market refrigerators, cold storage rooms, and the rooms of residences, oice buildings, etc.

In residence and office cooling it is ordinarily desirable to decrease the humidity of the air as it passes through the conditioner; since, a decrease in humidity results in a greater rate of evaporation of perspiration in the persons subjected to the conditioned air. In this case, the cooling unit is comparatively small, and the temperature difference is likewise comparatively small, since comfortable living conditions never require the air to be lowered anywhere near the freezing point. In other Words, a small cooling unit circulating hot humid air will decrease the humidity thereof.

On the other hand, a comparatively large unit used for refrigeration purposes in a cooler or cold storage room may cause an increase in relative humidity, since the conditioned air is usually brought down to temperatures around the freez-A ing point. This refrigeration, obviously, causes shrinkage of the air originally in the cooler, and with a consequent suction of outside air, and its moisture content, into the cooler to compensate for this shrinkage. This results in an increase in relative humidity of the air in the cooler. This means that decrease or increase in humidity of a compartment or room will depend upon the size of the cooling unit as compared with the 35 size of said compartment or room, and with the drop in temperature which the unit is designed to effect.

The main object of the invention, therefore, is

to provide an air conditioning unit which is 40 highly efficient in operation, and in which the relative humidity of the air conditioned may be considerably increased by the cooling operation of the unit, or may be decreased where this is found necessary or desirable.

Other objects of the invention will become apparent as the detailed description thereof proceeds.

In the drawings:

Figure 1 is a top plan view of an air conditioning unit embodying the present invention, part of the casing being removed to illustrate details of construction;

Figure 2 is a vertical section taken on the line 2 2 of Figure 1; A

Figure 3 is a top plan View, similar to Figure 1, showing a modified form of the invention; and

Figure 4 is a vertical section taken on the line 4 4 of Figure 3.

In Figures 1 and 2 of the drawings, the unit is shown as comprising a base plate I, extended 5 rearwardly to form a support 2 for a motor 3 having its rotor shaft 4 extending in opposite directions from the motor casing. On each side of the motor there are arranged the blower casings 5 and 6 constructed to communicate at their upper ends with the conduit I forming part of an air cooling casing designated generally by the numeral 8.

The casing 8 comprises the base plate I, side walls 9 and I0, a top II and partitions I2 and l5 I3 extending across the casing parallel to the base plate I and dividing the casing into three conduits 1, I4 and I5. The conduits 'I, I4 and I5 are substantially equal in size, and are dimensioned so that each conduit can accommodate at least two grids of a cooling coil formed of piping having an outlet I 6 at the Warm air inlet of the conduit l. The top II is connected to the partition I3, at the exit end of the casing 8, by a semi-cylindrical casing Il; and the base plate I is likewise connected by a semi-cylindrical plate I8 to the motor end of the partition I2. By this arrangement, the conduits l, I4 and I5 form a continuous counterlow duct for conducting air from the air inlet I9 of the unit to the air outlet 20 thereof.

As will be apparent from the drawings, the piping forming the upper grid in the conduit 'I extends from the refrigerant outlet or suction connection I6 to the exit end of the casing 8. At this exit end, a bend 2I connects the upper grid 22 to the lower grid-23 in the conduit l. The lower grid 23 at the inlet end of the casing 8 is connected by a bend 24, which extends through the partition I2, to the upper grid 25 in the condnit I4. At the exit end of the casing 8, which is also the inlet end of the conduit I4, the upper grid 25 is connected by a bend 25 to the lower grid 2'I in the aforesaid conduit I4.

At the inlet end of the casing 8, the grid 21 is connected by a bend 28, passing through the partition I 3, with the grid 29 in the upper part of the conduit I5. The grid 29, at the exit end of the casing 8 and of the conduit I5, is connected by a bend 30 to the lowermost grid 3I, which, at the inlet end of the casing 8, is connected to the inlet end 32 of the entire coil system contained within the several conduits 1, I4 and I5.

It will be noted from the foregoing disclosure thatv the Warm air forced into the conduit 'I by the blowers contacts with the warmest part of the cooling coils. 'Ihis construction and mode of operation enables the refrigerant to absorb the greatest number of heat units possible for lt to contain at temperatures prevailing at the exit or suction end thereof. In this respect, the present cooling unit operates directly opposite to the Acooling devices of the prior art.V In other words,

the warm air contacts the warmest part of the coil; and the cold or conditioned air emerges from the coldest end of the unit.

This arrangement and mode of operation have the effect -of reducing or practically eliminating condensation. It is obvious that the nearer the temperature of the coil to that of the air impinging thereon, the less will be the condensation. This effect continues throughout the entire length of the conduits from inlet to exit. In other words, the decrease in temperature of the air being conducted through the air ducts of the unit is effected gradually and not in sharp steps as would be the case if the warm air were forced initially against the coldest part of the coil system to emerge at the warm end thereof. v

The grids of each compartment are traversed by aseries of fins 33, preferably of aluminum, and extending perpendicularly to the convolutions of the grids in each compartment. These ns are preferably constructed and arranged on the grids substantially as disclosed in the United States patent to Larkin, No, 1,776,235, September 16, 1930; and each extends substantially the entire length of the conduit ln which it is arranged.

As disclosed in the aforesaid Larkin patent, the coils provided with these vertical flns are highly eicient and reduce the temperatures of air passing therethrough with great rapidity. Moreover, the temperature differential between the coils and the air conditioned thereby is so smallthat to bring the air down to any desired temperature, it is only necessary to maintain the refrigerant inlet end of the coil at about one de.

gree below that of the air as it emerges from the exit end of the unit.

It must be distinctly understood that this invention is not to be considered as in anyway limited to the number of air conduits arranged vin the casing, or to the number of grids of cooling coils which may be arranged in-each conduit. It must also be understoodthat the invention is not to be considered as vlimited to-the use of any particular number of cooling grids in each conduit. It is desirable, of course, that the coldest end of the coils shall be at the exit end of the casing. This result could obviously be obtained by using three grids zigzagged in the conduit I5. However, the nal result is not substantially affected by using thetwo grids as shown in conduit I5, and which, therefore, require the cold inlet end of the coil system to be positioned at the warm air end of the unit. In the ideal system, however, the cold inlet of the cooling coils should be located at the cooled air exit.

In the modification shown in Figures 3 and 4, the blower mechanism and casing are substantially the same as the blower mechanism, and casing shown in Figures land 2; and the corresponding parts thereof are designated by the ranged with a motor at the bottom of the counter so as to expel cold air out o-f the top of the unit toward the center of the refrigerator in which case it may be convenient to use a duct extending from the outlet of the unit along the top of the counter case. The unit may also be disposed with the motor and fans below the tori of the counter to expel the cold air toward the center ofthe case and along the bottom thereof. In other words, the operation of the invention disclosed herein is not in any way dependent upon its being arranged in any particular position in any refrigerator or compartment.

While not shown nor described in this application, it is to be understood that the unit will be provided with the usual adjustable thermostatic controls to regulate the operation of the refrigerant coils and the temperature of the air conditioned by the unit. These thermQstatic switches and valves controlled thereby are very well known in this art; and form no essential part of the present invention.

It is thought that the invention and numerous` of its attendant advantages will be understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts Without departing from the spirit or scope of my invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for therpurpose of illustrating my invention.

What I claim is:

1. An air conditioner comprising: a casing having a series of superposed conduits extending lengthwise therethrough, means for connecting the adjacent ends of said conduits in series to provide a continuous circuitous air duct through all of said conduits, meansfo'r forcing air through said duct, means extending transversely of each conduit for cooling the air during its passage mounted in saidcasing and having grid branches extending substantially across each of said conduits, and cooling fins extending lengthwise of each conduit and Vin heat conducting contact n across said branches. y

LESTER U. LARKIN.

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