US2102762A - Refrigerating apparatus - Google Patents

Description

Dec. 2l 1937. .Q M SUMMERS 2,102,762

' REFRIGERATING Y APPARATUS Filed July 1o, 1934 4 sheets-Sheet 1 70y I i 70 M. SUMMERS REFRIGERATING APPARATUS Filed July 1o, 19:54 7 4 sheets-sheet 2 4. 7 6 1 6 6 A 9 6 01 7 7 Hlwii,

o, M. sUMMERs REFRIGERATING APPARATUS Filed July 1o, 1934 4 Sheets-Shea?f 3 Dec. 21, 1937. 2

O. M. SUMMERS REFRIGERATING APPARATUS Filed Ju] .y 10, 1954 4 Sheets-Sheet 4 Put-med Dec. 21, 1937 .PATENT QFFICE' 3,102,762 nsrnrosanrmo Armures I Otto M. Summers, Dayton, Ohio, assignor to Gen.

eral Motors Corporation, Dayton, Ohio, a oorporation or Delaware Application my 1o, 1934, serial No. s134,524

This invention relates to refrigerating apparatus and more particularly to means for controlling the operation of refrigerating systems. This application is a continuation in part of my application Serial No. 145,950 filed November 3, 1926, which has matured into Patent No. 2,035,575 issued March 3l, 1936.

Refrigerating systems are normally controlled by starting and stopping the circulation of refrigerant in the system according to certain high and low pressure and temperature limits. Heretofore, in adjusting these limits, a change in one of the limits would eiect the other limit, even when not desired. This made the task of setting the proper limits of controlling an extremely difiicult one.

It is an object of my Ainvention to provide an improved refrigerating system controlled by starting and stopping the circulation of refrigerant according to predetermined high and low temperature and pressure limits, which system is provided With means for setting and adjusting each of the limits entirely independently of the other.

It is another object of my invention to construct a refrigerating system in such a way that the' controller diaphragms are protected from pressure 'pulsations within the system. It is a further object of my invention to provide av refrigerating system which is controlled by the pressure or temperature dierential between the high pressure portion of the system and the low or evaporating portion of the system.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: t Fig. 1 is a front view partly in section of `an improved controller for controlling the operation of.

The present-invention is particularly adapted to refrigerating systems in which it is desirable to render a motor operative when a predetermined high temperature is present, and render the motor inoperative when a predetermined low temperature is present. Fig. 4 shows one manner of connecting the present controller in a refrigerating system. Thesystem includes a compressor 88 which is driven by a motor 8l. 'Ihe (Cl. 6M)

compressor is adapted to withdraw refrigerant from an evaporator B8 through a pipe 99 and force the compressed refrigerant through a pipe 99 int'o a condenser 9|, whence it passes by a pipe 92 to the evaporator 88. The chamber 29 of the controller 29 is connected by 'a pipe- 93 with the low pressure pipe 89. When the` motor tl' andsure within the low pressure side of refrigeratingsystem to decrease and when said pressure falls to a predetermined value, which .value is computed 4in accordance with the temperature desirecl in the evaporator 89, the controller 29 will separate contact l@ from cmntact 99 to thus render the motor ill inoperative.'

In case the refrigerating system does not operate satisfactorily, as, for sample, the refrigerant in the condenser 9H is not cooled as required, the excessive pressure within the high pressure side oi! the system will be transmitted to cham-4 ber 2l through the pipe 9d, which pipe is connected on the highpressure side of the refrigerating system. When an excessive pressure is present within the system, the pressure within the chamber 21 will force the diaphragm 23 outwardly and rotate the lever 38, which lever 98 will operate through the pin 49 to rotate lever 93 in a counterclockwise direction, `whereby contact 'It is sep arated from contact 89.

In systems in which there is present periodic pulsations such as those caused by the operation of a compressor and in which the diaphragm is subjected to these pulsations, said vdiaphragm is vibrated at a relatively high speed on each impulsation. This, in effect, will cause the diaphragm to fracture quickly. In the present invention this objection has been overcome by preventing the vibration of said diaphragm. The pipes 93 and 94 have a relatively small cross-sectional area and are of such length so as to provide a resistance to the flow of refrigerant to such an extent that the pulsations are not transmitted to the chambers 21 and 28. By providing this resistance, the pressure values do not change rapid- .lywithin said chambers and said chambers are responsive only to the mean pressure within the respective high pressure and low pressure sides of the refrigerating system. By subjecting said diaphragms only to the mean pressure within the system, no pulsation is present within said chambers and, therefore, the diaphragms 23 and 2l vwill not vibrate.

In Fig. there is shown a direct expansion type of refrigerating system embodying my inveno0 tion. 'I'his system includes a compressor |||I for compressing the refrigerant and for forwarding the compressed refrigerant through a conduitl to a condenser ||2 where the compressed refrigerant; is liqueed and forwarded through a supply conduit ||3 to an expansion valve ||4. The expansion valve .||4 is located within an insulated enclosure ||5 and controls the supply of liquid refrigerant to an evaporating means ||6 located in heat exchange relation with the interior of the enclosure. The evaporating means ||6 absorbs heat from the interior of the enclosure and evaporates the liquid refrigerant, which is returned through the return conduit ||1 to the compressor. The compressor is driven by an electric motor ||9 which is started and stopped by my improved controller 20, which is located in series with the electric motor circuit |2| whichl supplies electric energy to the electric motor I |9. The chamber 28 of the controller 20 is connected by a pipe |93 with a thermostatic bulb |94 which is located in heat exchange relation with the evaporating means H6 and which is, therefore, responsive to the temperature as well as the pressure of the evaporating means lli. When the motor I9 and the compressor il! are idle, the evaporator becomes warmer and the volatile refrigerant within the thermostatic bulb |94 expands, thus increasing the pressure within the tubing |93 and the chamber 28 and when such pressure attains a predetermined value, the con` tact 14 will close with contact 30 to complete the electrical circuit to the motor H9. The operation of the compressor ||l will evaporate liquid,

refrigerant within the evaporating means to decrease the temperature of the evaporating means and the interior of the insulated enclosure ||5. This will also reduce the temperature of the thermostatic bulb |94, thus causing the pressure within the tubing |93 and the chamber 25 to be reduced, and when said pressure falls to a predetermined value, which value is computed in accordance with the temperature desired in the evaporator IIS, the controller 2|! will separate the contact 14 from the contact 80 to thus stop the electric motor ||9.

In case the refrigerating system does not operate satisfactorily, as, for example, when the reirigerant in the condenser ||2 is not cooled as required, the excessive pressure `within the high pressure side of the system will be transmitted to the chamber through the pipe which preferably has a relatively small cross sectional area so as to provide a resistance to the flow'of refrigerant to such an extent that the pulsations within the system are not transmitted to the chamber 21. 'Ihis pipe |95 is connected to the conduit which is in open communication with the condenser ||2. When an excessive pressure is present within the system, the pressure within the chamber 21 will force the diaphragm 23 outwardly and rotate the lever 33, which lever 33 will operate through the pin 45 to rotate the lever 43 in a counterclockwise dlrection whereby contact 14 is separated from the contact 30. Thus, the controller in reality is controlled by both the pressure within the conv denser and the temperature and pressure of the evaporating means.

Referring to Figs. 1 to 4, the controller 2l in'- cludes a base 2| to which is secured an upright 22. Adjacent the lower portion and on opposite sides thereof, there are provided diaphragms 23 and 24 which are spaced from the'upright 22 by gaskets 25 and 26 to provide chambers 21 and 28, respectively, between said diaphragm 23 and upright 22, and between upright 22 and diaphragm 24. Plates 29 and 30 are also disposed on opposite sides of the upright 22 and are arranged coextensive with the diaphragms 23 and 24. The diaphragms, gaskets and plates are suitably secured to the upright'22-by screws 32. A disc 33 `is disposed between the plate 29 and the diaphragm 23, and a disc 34 is disposed between the diaphragm 24 and plate 39. Ears 36 are carried by the plate 29, which ears support the fulcrum pin 31 upon which is pivotally mounted a lever 33. One end of lever 38 is arranged to be engaged by the disc 33 and the other end of said lever engages a pin 40 which extends through the upright 22. The plate 30 carries ears 4|, which ears support a fulcrum pin 42 which in turn carries an operating member or lever 43. The lower end of said lever 43 is arranged to engage with pin 40. A pin 44 pivotally connects lever 43 with ears 45, which ears are secured to the disc 34.

The plate 29 is tapped at 46 to receive a coupling which is connected with a source oi pressure, and a passage 41 connects said tapped p ortion with the chamber 21, said passage including a drilled hole within the plate 29 and diaphragm 23 and a cut-away portion in the gasket 25. The plate 30 is tapped at 49 and is provided with a passage 49 similar to that of 41, which passage vthere is provided a sleeve 50 which extends through said upright and is suitably secured thereto. A plunger 5| extends through one end of said sleeve and the extreme end 'thereof is provided with a cone-shaped recess 52. A screwthreaded bushing 53 is connected with the opposite end of the sleeve 50 and a spring 54 is located within the sleeve 50 and is disposed between the bushing 53 and a stop 55, and normally tends to force the plunger 5| to the right. .Stop 55 engages the end wall of a sleeve `5|! and thus limits the movement of said plunger 5|.

A stem 51 is located above the pin 5| and extends through the upright 22. Stem 51 is provided with a stop 58 to limit the movement of said stem toward the left. A nut 59 is provided on said stem 51 and a spring 60 is interposed between said nut and the upright 22 and normally tends to move the stem toward the left. Stem 51 carries a pin 5| which is slidably movable within a slot 52 formed in lever 43. Ears 64 are provided by the upright 22 and extend par# allel to the 'plunger 5| and the stem 51. A fulcrum pin 55 is carried by the ears 54, which in turn Vcarries an actuating mechanism including parallel-spaced arms 55 which support a roller 51. A spring 59 is wound about the pin 55 and normally tends to rotate said roller 51 in a clockwise direction.

A switch lever 19 is bodily or translatively carried by the lever 43, byv a pin 1|. The lower 18 to prevent the counterclockwise movement of e said contact 14 beyond a certain limit. Contact 14 is arranged to engage with contact 88 carried by the insulating block 11. The upper .end'of lever 18 is provided with a cam 82 havingcamming surfaces 83 and '84 either' of which is arranged to cooperate with the roller 61. When the roller 61 engages the camming surface' 84, the lever 18 will be in the position shown in Fig. 1, the stop 19 of the pivoted contact 14 limiting the movement of the lever 18. When the lever 43 is moving outwardly, carrying with it the lever 18, the camming surface 84 will move over the roller 61 and after the apex, formed by the camming surfaces 83 and 84, has moved beyond the roller, the roller 61 will engagel the camming surface 83. When this occurs, the spring 68 will force the roller 61 downwardly, which in turn will quickly rotate the lever 18 in a clockwise direction. When thelever 43 moves in the opposite direction, lever 18 will be moved, so that the camming surface 83 will be moved beyond the roller and when said roller engages surface 84 the lever 18 will .quickly rotate about pivot 1I in a counterclockwise direction. Fig. 1 shows the position of lever 43 while said lever is moving toward the right and the lever 18 is still in the position in which the roller 61 maintainsv contact 14 separated from contact 88. A still further movement of the lever 43 to the right is necessary before camming surface 83 engages roller 61. Fig. 2 shows the position of lever 43 while said lever is moving toward the left, the camming surface 83 being still in engagement with the roller 61. yA further movement of the 'lever 43 tothe left is necessary before surface 84 engages said roller. It will be noted that when the lever 43 is moving toward the right, the ful-y crum pin 'H lof lever 18 is farther to the right when the apex of cam 82 engages roller 61, than when the apex engages roller 61 while the lever 43 is moving toward the left. .This is the result of the lever 18 being pivotally and translatively carried by the lever 43 since the lever 18 is at vadifferent angle while said lever 43 is moving in one direction than the angle of lever 18 when lever 43 moves in the opposite direction. movementl of the lever 43 to the right is resisted by the spring 68 and the movement of the lever 43 to the left is resisted by the spring 54, there being a projection 85 on the lever 43 which is adapted to engage plunger 5I to' compress the spring 54. The arrangement is such that the stop 55 on the plunger 5| will engage the en d wall of sleeve 58 before the lever 43 has moved to such a position in which the camming surface 84 has moved beyond the roller 61, and the,

stem -51 will engage the. upright 22 and thusrender the spring ineffective as regards to lever 43. While-the camming surface 83 isstill engag-A `ingroller 61, projection- 85 on` lever 48 will engage the plunger. 5I.. Thus 'the spring 54 will'- resist the movement of the lever 43: to the left The- As thepressure within the:

and the tension of this spring can be adjusted by the nut 53. Since spring 88 is now ineective. the tensiony of spring 54 alone controls the pressure at which the contacts 14 and `88 are separated. 'Ihus it is apparent from the foregoing description that there is provided high and low pressure adjustments which are entirely independent of one another, whereby the pressure at which the contacts are closed canv be adiusted entirely independently of the, pressure at which the contacts are opened and. likewise, the pnessure at which the contacts are opened'. can be adjusted independently of the pressure at which the contacts are closed. y

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope ofthe claims which follow.

What is claimed is as follows:

i. Refrigerating apparatus comprising a closed refrigerating system having means for circulating condensing and evaporating refrigerant; means for automatically controlling the circulation of refrigerant including means for controlling the starting and stopping of the circulation of refrigerant according to predetermined temperature period when the other separatemeans is not acting effectively.

2. Refrigerating apparatus comprising a closed refrigerating system having means for circulating condensing and evaporating refrigerant, means for automatically controlling the circulation of refrigerant including means for controlling the starting and stopping of the circulation of refrlgerant according to 'predetermined temperature limits, and separate means for separately adjusting the starting and stopping of the circulation entirely independently of and without affecting the critical points controlled by each other.

3. Refrlgerating apparatus comprising a closed refrigerating system having means for circulating condensing and evaporating refrigerant, means for automatically controlling the circulation of refrigerant including means for controlling the starting and stopping of circulation of refrigerant according to predetermined temperature limits, and means for adjusting the stopping of the circulation without'afiecting the critical point or any adjustment which determines the starting of the I circulation. e

4. Refrigerating apparatus comprising a closed refrigerating system having means for circulating, condensing, and evaporating refrigerant, means for automatically controlling the circulation of refrigerant including a plurality-of separately confined spring means acting independently -for separately controlling the starting and stopping of circulation of refrigerant according to predeterminedtemperature limita-each of said independently acting spring meansl actin-g effectively solely during .a period^when the other independently confined spring means is, not actingl effectively.

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