US2262234A

US2262234A - Multitemperature refrigerating system

Info

Publication number: US2262234A
Application number: US388041A
Authority: US
Inventors: Anthony F Hoesel
Original assignee: Peerless of America Inc
Current assignee: Peerless of America Inc
Priority date: 1941-04-11
Filing date: 1941-04-11
Publication date: 1941-11-11
Anticipated expiration: 1958-11-11

Description

Nov. 11, 1941. A. F. HOESEL 2,262,234

MULTITEMPERATURE REFRIGERATING SYSTEM Filed April 11, 1941 s Sheets-Sheet 2 Fig.5 4.2;

Nov. 11, 1941. A. F. HOESEL 2,262,234.

MULTITEMPERATURE REFRIGERATING SYSTEM Filed April 11, 1941 3 Sheets-Sheet 3 I U! 2 g .5

.s I 1 w E c 22 F: LE

a I EL 2 B I [0 O m In Q In N N w-l w-l Lbs Per SQ. In VacuunJ lnchesHq.

Suction Line Cause Press.

lnvento l of Fig. 1.,

UNITED :STATES PATENT OFFICE MULTITEMPERATURE REFRIGERATIN SYSTEM Anthony F. Hoesel, Chicago, Ill., assignor to Peerless of America, Incorporated, Chicago, 111.,

acorporation of Illinois Application April 11, 1941, Serial No. 38 8,041

4 Claims.

The present. invention relates to refrigerating systems-in which severalcooling units are employed to maintainvarious temperature levels in I the respective compartments in which such cooling units are located.

Since these cooling units have a circulation of a volatile refrigerant, by means of a common compressor evacuating refrigerant vapor therefrom and furthermore since the pressure, of the volatile refrigerant, is proportional to it's temperature the present invention contemplates closing the vapor outlet of the higher temperature cooling units whenever they have reached their desired temperature as reflected by the pressure of the volatile refrigerant.

Previous multi-temperatu're refrigerating systems were controlled by means of thermostatically operated solenoid Valves, snap action suction line control valves or mere pressure throttling valves. All of such systems had the common defect that the higher temperature cooling units might cut. into the circuit long before the lowest temperature cooling unit arrived at its desired low temperature. In such cases it is impossible to maintain the low-temperatures desired since the volatile refrigerant pressure, in the low temperature units, would be much less than the volatile refrigerant pressure in the higher temperature cooling units, I

An object of the present invention is to provide an improved multi-temperature refrigerating system in. which thevarious cooling units will cut out of the refrigerant circuit as their various desired temperatures are reached.

Another object 'of the invention is to provide animproved multi-temperature refrigerating system in which the higher temperature cooling units cannot cut into the refrigerant circuit until the demands of the lowest temperature cooling unit is satisfied. a A further object of the invention is to provide Fig. 5'is a diagrammatic view of a multi-temperature refrigerating system embodying the invention.

Fig. 6 is a chart showing the operating charsuch as Fig. 4, embodying the invention.

In the drawings:

In Figs. 1 and 2, the suction line out off valve 1 comprises a casing 8 having an inlet 9 and an outlet l0 between which is disposed a valve I I having asmall leak orifice 2. Th valve ll engages-a seat 13, in the-casing 8, under the urgement of the diaphragm H which is pressed downwardly by means of the diaphragm spring; I5. The pressure of the refrigerant, at the outlet I0, tends to press the diaphragm l4 upwardly,

acteristics of a typical multi-temperature system I against the forc of the spring l5, and the valve spring I6 tends to move the valve H upwardly and open the full passage between the inlet 9 and outlet I U. o

A cover 11, screw threaded to the casing 8, at l8, clamps the diaphragm l4 thereto and serves as an abutment for the non-rising stem adjusting screw IS, the upper end of which projects through a new type of refrigerantsuction linelcut off lower temperature cooling units.

the bore 20 of the cover I'I.

The cover I! has two slots 2! loosely engaging the lugs 22 of the spring seat 23 which is threade dly engaged by the adjusting screw 19, whereby turning of the adjusting screw l9 results in lengthening or shortening of the diaphragm spring I5 and consequently decreasing and increasing respectively the amount of spring pressure exerted upon the diaphragm Hi.

The adjusting screw 19 has a central bore 24 inwhich a feeler pin 25 loosely plays. In the fabrication of this cut off valve], I engage the valve II with its seat l3 and then make the feeler-pin 25 of such length that it is even with the top 26 of the adjusting screw 18, which, being between the inlet 34 and the outlet .35 opens the Fig. 4 is an elevational view, partly in section.

of a suction line pressure operated starting and stopping switch,

valve 36 which .is' pressed against its seat 31 by means of the spring 38; Whenever the-pressure, at the outlet 35, equals or exceeds the pressure at the'inlet 34, the-valve 36. stays'closed thereby preventing a reversal of the fluid flow.

In Fig. 4, the suction line pressure operated starting and stopping'switch '44, which hereinafter for purposes of brevity will be termed pressurestat, comprises a casing 45 in which is mounted a bellows 46,.havlnga capillary tube 41,,

which contacts a lever arm 48 pivoted at 49..

An adjusting screw 50, threadedly engaging the casing 45, presses upon a spring support 5| serv- 5 ing as one abutment oi the spring 52, whose other end presses down upon the lever. arm 48. In consequence the adjustment, of the adjusting {screw 50, serves to vary the pressure necessary,

Within the bellows 45, in order to move the lever.

a stationary'contact 55 to whichjs connected an electrical conduit 56. The movement of the lever arm 48, under the influence of the pressure within the bellows 45, makes and breaks an electrical circuit between the contacts53 and 55, a rising pressure tending to. make the electrical circuit and vice versa.

. -In Fig. 5, themulti-temperature refrigerating system comprisesthe refrigerated compartments 65, 51 and 58in which are placed the cooling units '69, I0 and II' respectively, which have

suction lines

18, 13 and. 14 respectively connected to a common suction line'15 from which refrigerant vapor is evacuated by means of the compressor 15 driven by the electric motor 11 under thecontrol of the pressurestat 44 which makes and breaks the electrical circuit responsive to the pressure conditions within the suction line 15- to which the capillary tube 41 is connected as shown.

The compressor I5 compresses the refrigerant vapor into the-condenser [8 in which it surrenders heat and becomes liquified. The liquidrefrigerant leaves the condenser 18 by means of the liquid conduit 19 from which supply conduits 80, 8| and-82 serve to feed the

thermal expansion valves

83, 84 and 85, which in turn feed refrigerant liquid to their respective cooling units responsive to superheat conditions, of the refrigerant vapor, at the points to which their re- '

spective temperature feelerbulbs

85, 81 and 88 are clamped as shown.

Since thermal expansion valves are well known and so universally used throughout. the art,-it will sufiice to state that they tend to feed retity and at such rate of flow that. the vapor, leaving such cooling unit, will have some definite de gree of superheat- As the compartment temperatures drop, the thermal expansion valves necessarily decrease the rate of refrigerant feed to the cooling units, consequently the refrigerant pressures, withinthe coolingunits, also correspondingly drops.

The outlet, of the cooling unit 59, connects to a .cut. ofi valve 7 which in turn connects to the suction line 12. n

The outlet, of the cooling unit 10, connects to a cut off valv I which in turn connects to the suction line 13in which is mounted a check valve 33.

The outlet, of the cooling unit H, connects tothe suction line :14 in which is mounted a check valve 33. n 1

We shall assume that the refrigerant used is methyl chloride, that compartment 55 shall be 33 F. with a 10 F. temperature of the cooling unit 59, that compartment 51 shall be 5, F. with a -10 F. temperature of the cooling unit 10,

that compartment 58 shall be 2 F. with a -20 F. temperature of the cooling unit. ll.

Assuming the systemat rest and the vapor 7 shall be explained later.

pressure building .up in'the suction line 15, as The suction cut off valves 1 are assumed to be open. The pressurestat 44 is adjusted to make contact, and establish thev current flow to the motor 11, whenever the pressure increases to 24 1bsl'- per square inch gauge, which, for methyl chloride, is equivalent to a temperature of 35 The compressor l5,now starts up and evacuates vapor from the suction line 15. At this time the refrigerant pressure, within the suction line 15,

isgenerated solely within the cooling unit 59. I

Referring to the chart, Fig. 6,. indicates the starting point at D, which is 24 lbs. pressure. The line D toE indicates that the pressure,.within the cooling unit 69. over a period of approximately 10 minutes elapsed compressor running time, drops to 8 lbs, giving a temperature of 10 F. to the cooling unit 59. The particular cut oii valve 1 is now adiustedto close all at 8 lbs. pressure. A

At this time the pressure, within the cooling unit I0, is approximately 4 lbs. and the suction line 15 readily evacuates to this value as indicated by the line E to F at which time the check valve 33 allows a flow therethrough. The line F to G indicates that the pressure, within the cooling unit 10, drops to 0 lb. gauge,'during an elapsed compressor running time of approximately 9 minutes, which gives a -1 0 F. temperature to the cooling unit 10. The respective cut off valve 1 is now adjusted to close ofi at 0 lb. gauge pressure. i

' At this time the pressure,"within the cooling unit II, is 1'. vacuum to which the suction line readily evacuate s as indicated by the line G to H.

'The check valve 33, serving the cooling unit II,

now opens, and the pressure, within the cooling unit 'Il, drops to 5" vacuum during 7 minutes operating time of the compressor, as indicated by line H to A. At this point the temperature, of the cooling unit I l, is down to -'-20 F. and the pressurestat 44 is now adjusted to break the elec-- upon only one unit at a time, the various units frigerant liquid, to a cooling unit, in such quancutting out of circuit progressively.

During the compressor operation, upon the 59. -This same condition also exists with the particular cut oil valve I, connected to the cooling unit- It, whenever the compressor is operatingupon the cooling unit-II.-

\ This leakage is relatively unimportant from the standpoint of seriously aflecting the. compressor capacity when operating upon the lowest ten'iperature unit 'Il.

When the compressor closes down, both of the I cut of! valves 1 are leaking into the suction line 15, as indicated by lines A to B. At. point Bthe cut on valvel, connected to cooling unit 10, opens wide. At some point, intermediate between B and C, the pressure, within the suction line 15, equals the pressure in the cooling unit Hi and then its associated check valve 33 closes and prevents a reverse pressure-flow into the cooling within the suction line I5, takes a big jump to 2,262,234 approximately 22 lbs. pressure During a lapse of approximately 7 minutes the pressure, within the cooling unit 69 and the suction line 15, reaches a value of 24 lbs., due to the temperature increase of the cooling unit 69, and the pressurestat 44 again starts the ,compressor, and the previously explained operating cycle, as indicated by line D to A, recurs.

While the above description relates to a particularsystem operated under particular condi tions of compartment and cooling unit temperatures and with a particular refrigerant; it will be readily evident, .to those versed in the art, that many variations may be employed without 1 departing from the spirit and scope of the invention, which is to be limited only to the hereto appended claims.

I claim: 4

1. In a multi-temperature refrigerating system comprising a plurality of compartments to.be

the cooling unit in the compartment of highest temperature and controlled to stop upon some certain low suction pressure developed'during the I operation of said compressor upon the cooling unit in the compartment of lowest temperature,

- the combination of automatic valve means, at the outlets of the higher temperature cooling units,

responsive to lowering suction pressure, during the operation of said compressor, to progressive 1y check the outlet flow of first the highest temperature cooling unit, second the next highest temperature cooling unit and so on in a temperature descending scale.

2. In a multi-temperature refrigerating sys- -tem comprising a plurality of compartments to be maintained at certain temperatures by means of the circulation of a volatile refrigerant, be-

tween the inlet and outlet of cooling units disposed in said compartments, responsive to a single refrigerant compressor means controlled to start uponsome certain high suction pressure 1 generated by the cooling unit in the compartment of highest temperature and controlled to stop upon some certain low suction pressure de-,

veloped during the operation of said compressor upon the cooling unit in the compartment of low- 1 est temperature, the combination of automatic valve means, at the outletsfof the higher temperature cooling units, responsive to lowering suction pressure, during the operation of said compressor, to progressively check the outlet flow of first the highest tem rature cooling unit,

second the next highesttemperature cooling unit and so on in a temperature descending scale, said automatic valve means substantially but not.

wholly restricting all flow therethrough when in closed position.

3. In a multi-temperature refrigerating systein comprising a plurality of compartments to be maintained at certain temperatures by means oi. the circulation of a volatile refrigerant, between the inlet and outlet of cooling units disposed in said compartments, responsive to a single refrigerant compressor means controlled to start upon some certain high suction pressure generated by the cooling unit in the compartment of highest temperature and controlled to stop upon some certain low suction pressure developed during the operation of said compressor upon the cooling unit in the compartment of lowest temperature, the combination of automatic valve means, at the outlets of the higher temperature cooling units, responsive to lowering suction pressure, during the operation of said compressor, to progressively check the outlet flow of first the highest temperature cooling unit, second the next highest temperature cooling unit and so on in a temperature descending scale, said automatic valve means substantially but not wholly restricting all flowtherethrough when in closed position, and check valves in the outlets of the lower temperature cooling unit 4. In a multi-temperature refrigerating systern comprising a plurality of compartments to be maintained at certain temperatures by means of the circulation of a' volatile refrigerant, between the inlet and outlet of cooling units disposed in said compartments, responsive to a single refrigerant compressor means controlled to start upon some certain high suction pressure generated by the cooling unit in the compartment of highest temperature and controlled to stop upon some certain low suction pressure developed during the operation of said compressor upon the cooling unit in the compartment of lowest temperature, the combination of automatic valve means, at the outlets of the higher temperature cooling units, responsive to lowering suction pressure, during the operation of said compressor, to progressively check the outlet flow of first the highest temperature cooling unit, second the next highest temperature cooling unit and so on in a temperature descending scale, said automatic valve means substantially but not wholly restricting all flow therethrough when in closed position, and check valves in the outlets of the lower temperature cooling units, and said cooling units being fed, ,with refrigerant fluid,

by means of superheat controlled expansion valves.

ANTHONY F. HOESEL.