US3122001A

US3122001A - Safety device for refrigeration system

Info

Publication number: US3122001A
Application number: US233004A
Authority: US
Inventors: Freeman L Pritchett; Billy L Miller
Original assignee: IAN F LOCKHART
Current assignee: IAN F LOCKHART
Priority date: 1962-10-25
Filing date: 1962-10-25
Publication date: 1964-02-25
Anticipated expiration: 1981-02-25

Description

25, 1964 F. PRITCHETT ETAL 3,122,001

SAFETY DEVICE FOR REFRIGERATION SYSTEM Filed Oct. 25, 1962 FIG. I

INVENTORS FREEMAN L. PRITCHETTG BY BILLY L MILLER fad/W 2 M United States Patent 3,122,001 SAFETY DEVICE FER REFREGERATION SYSTEM Freeman L. Pritchett, 3965 Steele St, and Billy L. Miller, 2933 Semrnes, both of Memphis, Tenn., assignors of one-third to Ian F. Lockhart, Evansville, Ind. Filed Oct. 25, 1962, Ser. No. 233,004 Claims. (Cl. 62126) This invention relates to a safety device in a refrigeration system. More particularly, the present invention relates to a safety device that is responsive to the presence of acid in the refrigerant of the refrigeration system.

The present invention is particularly useful with that type of refrigeration system which uses a so-called sealed compressor unit in which the coils of the compressor motor are exposed in a housing to the refrigerant and which housing also contains oil. In this type of refrigeration system, there has been the problem of burn-outs of the motor and deterioration of other parts due to the undesirable presence of acid in the refrigeration system. This acid is caused by the presence of water in the system, which combines with the refrigerant and the oil in the presence of heat to for-m hydrochloric and/ or hydrofluoric acids.

-'The present invention is directed towards overcoming the above mentioned and other problems in refrigeration systems.

Thus, one of the objects of the present invention is to provide a safety device which is responsive to acid in the refrigeration system so that the acid can be detected when in small amounts and before it can do any harm.

A further object is to provide such a safety device which will automatically shut off the compressor motor at the first indication of acid in the system.

A further object is to provide such a safety device which actuates an alarm to notify persons of the presence of acid in the refrigeration system.

A further object is to provide such a safety device that can easily be reset after it has been actuated so that the device is in condition to subsequently detect the presence of acid in the system.

A further object is to provide such a device that is simple in construction and economical to manufacture.

A further object is to provide such a device which is positive in action and highly efiective.

A further object is generally to improve the design and construction of safety devices in refrigeration systems.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of ,their accomplishment will be readily understood from the following specification upon reference to the accornpanying drawings, in which:

FIG. 1 is a schematic diagram of a refrigeration system employing the safety device of the present invention.

FIG. 2 is an enlarged plan view of the safety device of the present invention, with fragments of the inlet and outlet pipes being shown in connection therewith.

FIG. 3 is a further enlarged fragmentary sectional view taken as on the line IIII'II of FIG. 2.

FIG. 4 is a side elevational view, with parts broken away for purposes of illustration, of a typical sealed compressor in use in the type of refrigeration system with which the device of the present invention is particularly adapted to beused.

Referring now to the drawings in which the various parts are indicated by numerals, and referring first more particularly to FIGS. 1 and 4, the typical refrigeration system shown, with which the safety device 11 of the present invention is adapted to be used, comprises a unit 13 which includes an air-tight housing or casing 15 into the interior of which flows the gaseous refrigerant R through an inlet pipe 17. A typical type of refrigerant 3,122,001 Patented Feb. 25, 1964 used is so-called Refrigerant 12, which has the formula of COlgFz and which is generically known as dichlorodifluoromethane. It will be understood that other types of refrigerants may be used in a system such as this, but the present invention is particularly useful with the refrigerants which for-m an acid when water is pres ent. It will be understood that the primary reason for this type of sealed unit 13 is so that the refrigerant will cool the motor and so that the oil in small quantities will mix with the refrigerant and will lubricate the various parts of the system.

The coils 21 of the compressor motor 23 are mounted in the usual manner in casing 15 and, as stated, are exposed to the refrigerant R. The usual vertical shaft 25 is driven by motor 23, and the shaft, in turn, drives the usual pump 27. The gaseous refrigerant -R is drawn in by pump 27 through an inlet pipe 29, which is exposed to the interior of casing 15, and is exhausted through outlet pipe 31. It will be understood that the part shown as at 33 in FIG. 4 is an oil pump also driven by shaft 25 and which pumps the oil to the various parts in the usual manner. -It is believed that the above general description of the typical sealed unit 13 is deemed sufiicient since it is well-known to those skilled in the art and since it forms no part of the present invention.

From sealed unit 13 pipe 31 leads to the usual condenser 35, over which the usual fan 37 moves air so that the refrigerant R condenses back to a liquid and flows through pipe 39 to safety device 11, which will be described more in detail later in the specification. :From safety device 11, the refrigerant R flows through a pipe 41 to the usual dryer 43 from where the refrigerant flows through a pipe 45 to the usual expansion valve 47. Then, the refrigerant R flows from expansion valve 47 through a pipe 49 to the usual evaporator 51 which is disposed in the place to be cooled, a for example, in a place to be air-conditioned or refrigerated. From the evaporator 51, the refrigerant R flows through inlet pipe 17 into the interior of casing 15, as heretofore described. From the foregoing description it can be seen that acid in the system, that is, in the refrigerant R, can do tremendous damage since the various parts and particularly the coils 211 are exposed to this refrigerant. Thus, the acid will eat through the insulation on coils 21, which will cause the coils to short-circuit and the motor to burn out. In addition, it can be seen that the other parts in the casing 15 and throughout the system will be readily attacked by the acid.

Referring now more specifically to safety device 11, the safety device comprises an air-tight housing 53 which includes a base 55 and a removable electrically insulated top 57. Base 55 includes a bottom 59 and an integrally formed upstanding wall portion 61 around the periphery of bottom 59. An annular internally threaded recess 63 is provided in the upper end of wall portion 61, which recess establishes an annular shoulder 65 in wall portion 61. Top 57 is preferably disc-like in shape and rests on shoulder 65, with an annular washer 67 preferably being interposed between top 57 and shoulder 65. An annular externally threaded retaining ring 69, having slots 70 therein for engagement by a suitable tool for the turning thereof, is threadedly engaged in threaded recess 63 and screwed down on top of top 57 to hold the top tightly in place and seal the top to base 55. Thus, top 57 defines with the interior of base 55 an enclosure '71 which is sealed off from the atmosphere.

Inlet pipe 39 extends through a bore 73 in wall portion 61 and is sealed therein by suitable means, with the end of the pipe opening into enclosure 71. In a similar manner, outlet pipe 41 opens into sealed enclosure 71 and leads therefrom through a bore 75 in wall portion 61 where it is sealed therein by suitable means against leakage. From the foregoing it will be understood that the refrigerant R passes from pipe 39, through sealed enclosure 71, and out pipe 41.

A rigid rocker arm 77 is pivotally mounted intermediate its ends in enclosure 71 for pivot about a horizontal axis as at 79. The means for pi'votally mounting rocker arm 77 is by any suitable means, and preferably by a bracket 81 mounted on the lower surface of top 57 and depending therefrom where the rocker arm is suitably pivotally attached. Rocker arm 77 is pivotable between a first position, shown in solid lines in FIG. 3, and a second position, shown in broken lines in FIG. 3. Resilient means, as a tension spring 33, is attached at oneend to top 57 and attached adjacent the opposite end to the portion 85 of rocker arm 77 which is to one side, or to the right, of pivot axis 79. For purposes of clarity, portion 85 will be herein designated the first end 85 of rocker arm 77, and the portion or end to the left of pivot axis 79, as viewed in FIG. 3, will be designated second end 87. Spring 83, it will be understood, urges rocker 77 to pivot counterclockwise, as viewed in FIG. 3. In other words, spring 33 urges rocker arm 77 to pivot in a direction from said first position towards said second position.

A holding member (59 engages rocker arm 77 to normally hold the rocker arm in said first position against the force of spring 83. Holding member 89 preferably comprises a bolt 91 and an element 93 attached to the end of the bolt by suitable means, as an epoxy resin or other adhesive or attaching methods. Bolt 91 is threadedly engaged in a threaded bore 95 through top 57 with the head 97 of the bolt 91 being on the outside of top 57 and with the shank 1610f the bolt extending clownwardly through the threaded bore 95 and below the lower surface. of top 57 in such a position that the element 93 engages first end 85 of rocker arm 77 to hold the rocker arm in said first position. A washer 1&3 is preferably interposed between head 97 and top 57 in surrounding relationship to shank H51 so that the device is sealed against leakage. It should be noted that the size of element 93 is less than the diameter of bore 5 so that holding member 85 can fit down into the bore. Element 93 is preferably in the form of a solid cylinder so that the element is, in effect, an extension of shank ltll. Thus it will be understood that when it is desired to replace holding member 89, this can easily be done merely by unscrewing the used holding member and screwing in a new one. Also, it will be understood that, due to the threaded relationship of bolt 91 and threaded bore 95, vertical adjustrnent of the element 93 is made possible. Element 93 is formed of a material that is dissolvable by acids, such as hydrochloric and hydrofluoric acids, and the material is preferably Zinc, although other acid dissolvable materials such as aluminum or the like may be used without departing from the spirit and scope of the present invention.

A pair of

electrodes

105 and 107 respectively extend through bores 169 and 111 in top 57 and are sealed therein against leakage, with the electrodes extending above and below top 57 for a portion, as best seen in FIG. 3. Electrode 105 is positioned so that it serves as a contact for rocker arm 77 and is in electrical contact with the rocker arm when the rocker arm is in said first position. The distal end of second end 87 is preferably enlarged, as shown in FIG. 3, where the actual electrical contact is made. Electrode 107 is electrically connected to rocker arm 77 by means of a flexible conductor 113 that is attached at one end to electrode M7 by suitable means, as soldering or the like, and attached adjacent the other end to first end 35 of the rocker arm, as by soldering or the like. The length of conductor 113 is such that the rocker arm 77 is free to pivot between said first and second positions without any restraint by the flexible conductor. It will be understood from the foregoing that a switch 115 is thus established by electrodes 165, 107, flexible conductor 113, and rocker arm 77. Switch 115 is preferably disposed in the electrical system of the refrigeration system in such a manner that the switch is in series with the compressor motor 23 and fan 37. Thus, the supply leads 117, 119 lead from the source of electricity, such as that indicated at 121, and switch is interposed in series in lead 119, as by means of the

leads

123, 125. Compressor motor 23 is connected across supply leads 117, 119 beyond the switch 115, as by means of

leads

127, 129, and fan 37 is connected in parallel with compressor motor 23 across the supply leads, as by means of

leads

131, 133. From the foregoing it will be understood that as long as switch 115 is closed, that is, when rocker arm 77 is in said first position, compressor motor 23 and fan 37 are energized, but that when the switch is opened, that is,- when the rocker arm moves away from the first position, the electrical circuit is broken and compressor motor 23 and fan 37 will stop running. Also, it will be understood that the above described opening of switch 115 will occur when acid gets into the system, which acid will dissolve the element 93, whereupon there will be nothing holding rocker arm 77 in said first position, and it will pivot to said second position.

A third electrode extends through a bore 137 in top 57 and is sealed therein against leakage, with the electrode extending above the top for a portion and depending therebelow where the lower end of the electrode is preferably J-shaped so that it extends underneath rocker arm 77 and thence upwardly to its point of termination, in position to be contacted by the rocker arm when in said second position. Thus, a switch 1455 is established by

electrodes

107, 135, flexible conductor 113, and rocker arm 77; which electrode 135, flexible conductor 113, and

rocker arm 77 are also common parts of the other switch I Suitable indicating means, such as a bell 151, is responsive to closing of switch 149, and this circuit is preferably connected as follows: A lead 153 extends from electrode 135 to bell 151, and another lead 155 also extends from the bell to a source of electricity, as a battery 157. A lead 159 extends from battery 157 to electrode 107. In other words, switch 149 is in series with battery 157 and bell 151 so that when rocker arm 77 moves to said second position, the circuit is completed through the bell for the ringing thereof to warn persons that there is acid in the system. It should be noted that, if desired, the switch 115 and its related wiring may be omitted, as for example, in cases where it is desired not to shut down the equipment but only to warn persons by the indicating means 151 that corrective action should be taken.

From the foregoing description it will be understood that the safety device 11 of the present invention provides a very effective automatic means for preventing any damage to a refrigeration system, of the type heretofore described, when any moisture gets into the system and is converted to acids. Also, from the foregoing description it can be seen that the holding member 89 can easily be replaced when a new one is needed, and, if desired, a complete assembly of the rocker arm 77, top 57, and the related parts can be easily replaced since the parts are all mounted as an assembled unit on top 57.

Although the invention has been described and illustrated with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of this invention as hereinafter claimed.

We claim:

1. In a refrigeration system, a safety device comprising means providing an enclosure through which the refrigerant in said system flows, a homogeneous and rigid element in said enclosure dissolvable in acids, means supporting said element in at least one fixed position in said enclosure, and indicating means including a movable member contacted by said element and normally held in a first p sition by said element, said indicating means he- 2) ing responsive to movement of said member from said first position upon dissolution of said element to indicate that acid is present in said system.

2. In a refrigeration system of the type having a compressor motor provided with an eiectrical circuit for the operation thereof, a safety device comprising means providing an enclosure through which the refrigerant in said system flows, a homogeneous and rigid element in said enclosure dissolvable in acids, and means supporting said element in at least one fixed position in said enclosure, and means including a movable member contacted by said element and normally held in a first position by said element, said last mentioned means being connected into said electrical circuit and responsive to movement of said member from said first position upon dissolution of said element to indicate that acid is present in said system.

3. A safety device for use in a refrigeration system, said device comprising a housing providing a sealed enclosure therein; said housing including -a base, a removable top mounted on said base, and retaining means holding said top on said base; means attached to said housing and communicated with said enclosure for introducing the refrigerant into said enclosure, a rocker arm pivotally mounted in said enclosure for pivot between a first position and a second position, resilient means attached to said rocker arm urging said rocker arm to pivot in a direction from said first position towards said second position, a first electrode sealingly extending through said top into said enclosure in position to be contacted by said rocker arm when in said first position, a second electrode sealingly extending through said top into said enclosure, flexible conductor means connecting said second electrode and said rocker arm, and holding means engaging said rocker arm for normally holding said rocker arm in said first position against the force of said resilient means, said holding means including means responsive to an acid to release said rocker arm from said first position.

4. A safety device for use in a refrigeration system, said device comprising a housing providing a sealed enclosure, said housing having an internally threaded bore extending from the exterior of said housing to said enclosure, a bolt having a head on the exterior of said housing and a shank threadedly extending through said bore, an element attached to said bolt to provide an extension thereof in said enclosure, said element being no larger than said shank whereby said element is removable through said bore, a switch in said housing, means coupled to said switch for urging said switch towards the actuation thereof, said element engaging said switch for normally holding said switch against the actuation thereof, said element being responsive to an acid in said enclosure to release said switch for the actuation thereof.

5. In a refrigeration system of the type having oil therein and including piping through which a refrigerant flows in contact with said oil and a compressor motor provided with an electrical circuit for the operation thereof, a safety device comprising means providing a sealed enclosure interposed in said piping in such a manner that the refrigerant flows through said enclosure, a rocker arm pivotally mounted in said enclosure for pivot between a first position and a second position, resilient means attached to said rocker arm urging said rocker arm to pivot in a direction from said first position towards said second position, holding means engaging said rocker arm for normally holding said rocker arm in said first position against the force of said resilient means, said holding means including an element exposed to the refrigerant in said enclosure, said element being formed of a material that is dissolvable by acids such as hydrochloric and hydrofluoric acids whereby when acids such as hydrochloric and hydrofluoric acids are present in said system said element dissolves which releases said rocker arm and permits said rocker arm to pivot to said second position under the influence of said resilient means, means in said electric circuit of said motor responsive to movement of said rocker arm away from said first position to shut off said motor.

6. In a refrigeration system of the type having oil therein and including piping through which a refrigerant flows in contact with said oil and a compressor motor provided with an electrical circuit for the operation thereof, a safety device comprising means providing a sealed enclosure interposed in said piping in such a manner that the refrigerant flows through said enclosure, a rocker arm pivotally mounted in said enclosure for pivot between a first position and a second position, resilient means attached to said rocker arm urging said rocker arm to pivot in a direction from said first position towards said second position, holding means engaging said rocker arm for normally holding said rocker arm in said first position against the force of said resilient means, said holding means including an element exposed to the refrigerant in said enclosure, said element being formed of a material that is dissolvable by acids such as hydrochloric and hydrofluoric acids whereby when acids such as hydrochioric and hydrofluoric acids are present in said system said element dissolves which releases said rocker arm and permits said rocker arm to pivot to said second position under the influence of said resilient means, means in said electric circuit of said motor responsive to movement of said rocker arm away from said first position to shut off said motor, and means responsive to movement of said rocker arm into said second position to indicate when said rocker arm is in said second position.

7. The apparatus according to claim 6 in which said element is composed of zinc.

8. The apparatus according to claim 6 in which said element is composed of aluminum.

9. The apparatus according to claim 6 in which said element is composed of tin.

10. in a refrigeration system, a safety device comprising means providing an enclosure through which the refrigerant in said system flows, a homogeneous and rigid element in said enclosure dissolvable in acids, a spring actuated switch, said element engaging said switch for holding said switch against the actuation thereof, said element being responsive to an acid in said enclosure to release said switch for the actuation thereof.

References Qited in the le of this patent UNITED STATES PATENTS Marsh Mar. 21, 1961