US2421258A - Control arrangement for refrigeration apparatus - Google Patents

Description

1947. M. B. GODDARD 2.421.258

CONTROL ARRANGEMENT FOR REFRIGERATION APPARATUS Filed Oct. 22, 1943 3 Shegts-Sheet l INVENTOR. fw, BY "MEL ATTORNEY.

y 1947' M. B. GODDARD 2,421,258

CONTROL ARRANGEMENT FOR REFRIGERATION APPARATUS Filed Oct. 22, 1943 3 Sheets-Sheet 2 FIG.2

INVENTOR. Ma a J BY a Ma ATTORNEY.

.FiG.3

May 27, 1947. M. B. GODDARD 2,421,258

7 CONTROL ARRANGEMENT FOR REFRIGERATION APPARATUS Filed Oct. 22, 1943 5 Sheets-Sheet 3 INV ENT OR.

ATTORNEY.

Patented ay 2?, 19d? CONTROL ARRANGERENT FOR REFRIG- ERATION APPARATUS Merrill B. Goddard, Chicago, 111., asslgnor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware- Application October 22, 1943, Serial No. 507,328

4 Claims. 1

This invention relates to the art of refrigeration and more particularly to an arrangement for improving the operation of thermal expansion valves.

Thermal expansion valves are often sluggish in action. If a thermal expansion valve closes due to lack of superheat, some time normally elapses before sufficient heat has been transmitted to the bulb to cause the valve to open; and during the interim the evaporators served by the valve will be starved of refrigerant and its ability to absorb heat at a desired rate considerably reduced.

The general object of the invention is to provide an arrangement for supplying a source of heat at a rapid rate and at a temperature within a desired range of difference with respect to the temperature of a suction line, to a thermal bulb attached to the suction line, so that an expansion valve controlled by the bulb will always remain in open condition.

A feature of the invention resides in the provision of a conduit arrangement for circulating air from a refrigerated space served by an evaporator coil over a thermal bulb attached in the usual manner to the suction line leading from the evaporator, the air being drawn into a fan section serving the coil.

Other features will be apparent from the following description of the invention to be read in connection with the accompanying drawings in which:

Fig. 1 is a diagrammatic illustration of a refrigerating system to which the invention has been applied.

Fig. 2 is a fragmentary diagrammatic view, in greater detail, of the conduit arrangementemployed for circulating air from a refrigerated space over the bulb serving the expansion valve of an evaporator, all elements of the conduit arrangement being positioned within the refrigerated space.

Fig. 3 is a sectional fragmentary view on th lines 33 of Fig. 2, and

Fig. 4 is a diagrammatic illustration similar to that of Fig. 2 except that the suction line and bulb attached thereto are positioned outside the refrigerated space.

Considering the drawings, similar designations referring to similar parts, numeral 5 designates a compressor, discharging refrigerant thru line b to condenser I, the liquefied refrigerant entering evaporator 8 thru expansion valve 9 controlled in the usual manner by thermal bulb 10 attached to suction line H thru' which the gaseous refrigerant is pulled to the compressor to complete the cycle.

The evaporator 8 is usually housed in a casin comprising a plurality of sections, one of which is a fan section, such as E3 of Fig. 2, wherein a fan, such as fan i2 of Fig. 1, usually of the centrifugal type, is positioned, and a coil section, such as It of Fig. 2, in which the evaporator a is located. Fan H of Fig. 1 is merely illustrative and intended to be a symbol representing any desired type of fan employed for circulating air over an evaporator coil. In the system of Figs. 1 and 2 the dash dot lines indicate an enclosure il within which the evaporator and associated fan apparatus are wholly positioned.

Considering the more detailed showing of Fig. 2, which in substance incorporates the same arrangement of expansion valve control embodied in the arrangement of Fig. 1, thermal bulb it is suitably attached by means of clamp It to make ood thermal contact with suction line i i. Jacket or sleeve is is positioned around the thermal bulb to provide an air conduit which is open at one end to the refrigerated space H. A second air conduit in the form of a tube or pipe id connects the other end of conduit it to fan section is subject to the suction of the fan. In Fig. 1

ous condition is pulled back to the compressor 2 a (not shown in Fig. 2) thru suction line H. Bulb it, in contact with suction line H, is not only subjected to the heat of conduction from line H. but is also subjected to the heat in the air circulated through conduits l6, 18. Since fan section i3 is below atmospheric pressure, a current of air from space I! is drawn over the bulb it at a considerable velocity. The air from space H is warmer than the refrigerant and therefore warmer than the thermal bulb II] when the suction gas is not superheated. Thus, bulb l0 absorbs heat from the air, especially whenever there is any appreciable lack of superheat, and the transfer rate will be relatively high due to the high air velocity over the bulb. Expansion valve 9 will therefore be prevented from closing for lack of superheat.

In Fig. 4, the arrangement differs from that of Fig. 2, in that suction line H is located outside refrigerated space ll. In this case, conduit 29 connects space ll to conduit l6 which, as in the arrangement of Fig. 2, is connected at the other end by conduit 58 to fan section l3. Insulating coating 23 provides heavy insulation for suction line ii, the conduit 16 surrounding the bulb and those portions of conduits l8 and 20 outside the refrigerated space. As a result, the tendency of the air circulated in contact with bulb i9 is to subject the bulb to an ambient temperature bearing substantially a constant relationship to the refrigerant temperature within narrow limits.

The arrows in Figs. 2 and 4 indicate the direction of how of refrigerant thru the coil section and of the air from space ll over the bulb.

Since variations in manner of application of the invention may suggest themselves to those skilled in the art, without departing from the principles involved, no limitation is intended with respect to the manner of achieving applicant's invention, except as prescribed in the appended claims.

claim:

3.. combination of, a coil section, a casing for said coil section, means including a superheat control expansion valve for admitting refrigerant to the coil section, a suction line connecting the coil section to a compressor, a thermal bulb all nod to and in thermal contact with said suction line, said bulb being operatively connected to said valve to cause said valve to function responsive to heat afiecting the bulb, a conduit surrounding the bulb, a conditioned space, a fan section positioned adjacent the coil section, means connecting said conduit to the fan section in such manner that air from the conditioned space will actively be circulated through said conduit, over the bulb and into the fan section.

2. In combination, a coil section, a fan secticn, said sections being located within a conditinned space, a superheat control expansion valve for controlling the admission of refrigerant to said coil section, a suction, line located outside said conditioned space and connected to said coil section, a thermal bulb in contact with said suction line, means connecting the bulb and valve to govern. the functioning of the valve in accordance with the heat afiecting the bulb, a conduit surrounding the bulb, a second conduit connecting said first conduit to the conditioned space, a third conduit connecting said first conduit to the far. section, all said conduits and suction 4 line being insulated so that air from the conditioned space will be actively circulated over the bulb at a temperature bearing substantially a constant relationship to the temperature of reirigerant in said coil section.

3, The combination of a heat exchanger, means including a superheat control expansion valve for admitting refrigerant to the heat exchanger, a suction line connecting the heat exchanger to a compressor, a thermal element disposed in thermalcontact with the suction line, said element being operatively connected to the valve to cause the valve to function responsive to heat afiecting the thermal element, a conduit surrounding the thermal element, a conditioned space, a member disposed adjacent the heat exchanger for passing air through the heat exchanger, and means connecting the conduit to said member in such manner that air from the conditioned space will actively be circulated through the conduit and over the thermal element.

4. In a device of the character described, the combination of a heat exchanger, fan means disposed adjacent said heat exchanger, said exchanger and said fan means being disposed within a conditioned space, a superheat control expansion valve for controlling the admission of the refrigerant to the heat exchanger, a suction line disposed outside the conditioned space and connected to the heat exchanger, 9. thermal element in contact with the suction line, means connecting the thermal element to said valve to govern the functioning of the valve in accordance with the heat affecting the thermal element, a conduit surrounding the thermal element, means connecting said conduit to the conditioned space, and means connecting said conduit to the fan means to pass air from the conditioned space through the conduit and over the thermal element.

MERRILL B. GODDARD.

I REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,319,005 Lum May 11, 1943 2,112,049 Roessler Mar. 22, 1938 2,222,236 Philipp Nov. 19, 1940 2,322,339 Beals June 2, 1943 2,242,334 Wile May. 20, 1941 2,230,905 Popky Feb. 4, 1941

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