US 3298192 A
Description (OCR text may contain errors)
R. D. MORGAN Jan. 17, 1967 CONTROL APPARATUS WITH TIMING MEANS FOR REFRIGERATION SYSTEMS FIG. I
ROBERT D. MORGAN. BYz/ JWM ATTORNEY.
United States Patent M ware Filed July 1, 1965, Ser. No. 468,837 9 Claims. (Cl. 62158) This invention relates to a refrigeration system, and more particularly, to a control arrangement for the compressor of the refrigeration system.
Refrigeration systems usually incorporate one or more protective devices, each effective at a certain malfunction in the system or the system compressor to render the compressor inoperative. Typical protective devices are, for example, an overtemp-erature sensor for the compressor motor windings, system pressure measuring devices, devices for sensing adequate compressor oil pressure, etc. On stoppage of the system compressor, whether as a result of a malfunction or, more commonly, the satisfaction of demand on the system, it is desirable that immediate restarting of the compressor be precluded.
In refrigeration systems which incorporate a control to prevent immediate restarting of the system compressor or compressors after stoppage thereof, where the compressor stoppage is due to a prevailing system or compressor malfunction, the compressor or compressors are nevertheless restarted, subject to the control imposed delay, indefinitely until the operator becomes cognizant of the system malfunction or the compressor becomes totally inoperative This situation is of particular concern in commercial systems where the system is apt to be left unattended for prolonged periods of time.
It is a principal object of the present invention to provide a new and improved control arrangement for refrigeration system compressors.
It is a further object of the present invention to provide a control arrangement effective to limit the number of compressor restarts that may be made within a predetermined period of time.
It is an object of the present invention to provide, in conjunction with a control for delaying restart of a compressor for a timed interval subsequent to each deenergization thereof, an apparatus effective to render the restarting control inoperative following a predetermined number of compressor restarts within a given period of time.
It is an object of the present invention to provide an apparatus which counts each deenergization of a refrigeration system compressor, effective, following a preset number of compressor deenergizations in a given period of time, to prevent further operation of the compressor.
It is a further object of the present invention to provide, in an apparatus for limiting the number. of compressor restarts in a given period of time to a predetermined number, means for automatically resetting the apparatus following the successful operation of the compressor.
The invention relates to a refrigeration system comprising in combination, a compressor, control means operable upon demand to energize the compressor; condition sensing means operable upon the occurrence of a predetermined malfunction to deenergize the compressor; timing means for preventing ree-nergization of the compress-or by the control means for a timed interval following each deenergization thereof; and means responding to a predetermined number of compressor deenergizations in the timed interval to render the control means inoperative. '4
Other objects and advantages will be apparent from the ensuing description and the accompanying drawings in which:
FIGURE 1 is a schematic representation of a refrigeration system incorporating the compressor control arrangement of the present invention;
FIGURE 2 is a wiring diagram of the compressor control arrangement of the present invention; and
FIGURE 3 is a perspective view illustrating the cycle counting mechanism embodied in the control arrangement shown in FIGURES 1 and 2.
Referring to FIGURE 1 of the drawings, there is shown a refrigeration system incorporating the control arrangement of the invention. The system includes an outdoor heat exchange coil or condenser 2 connected by means of line 3 with the discharge side of a suitable refrigerant compression mechanism, for example, a reciprocating type compressor 4. The gaseous refrigerant from compressor 4 flowing through outdoor coil 2 is condensed by ambient air from outdoor fan 5. Liquid refrigerant from coil 2 flows through line 6, thermal expansion valve 8, and line 9 to indoor coil or evaporator 10. It is understood that other suitable expansion devices, as a capillary tube, may be employed in place of expansion valve 8.
Liquid refrigerant in indoor coil 10 is vaporized by the stream of air from indoor fan 12, the cooled air being thereafter passed to the area being conditioned by suitable means (not shown). Vaporous refrigerant from coil 10 flows through line 13 to compressor 4. I
Referring to FIGURE 2 of the drawings, drive motor 16 of compressor 4 is connected through contactor 19 across leads L L Leads L L are connected to a suitable source of alternating current power (not shown). It is understood that a polyphase source of electrical power may be employed if the circuit is suitably modified.
Indoor fan motor 23 is connected by switch 25 across leads L L Outdoor fan motor 22 is connected by control relay switch 41 across leads L L Control relay 26 is series connected with temperature responsive switch 27 across leads L L Switch 27 responds to temperature conditions of the area being cooled.
Timer relay 48 is series connected by timer relay switch 49, system low pressure switch 40, system high pressure switch 44- and control relay switch 41 across leads L L Timer switch 32, when in the solid line position of the drawings, establishes a circuit bypassing timer relay switch 49.
Switches 44, 40 are arranged to sense refrigerant pressure conditions in discharge and suction lines 3, 13, respectively. Switch 44 deenergizes the compressor at a predetermined high refrigerant pressure in line 3 while switch 4% deenergizes the compressor at a predetermined low refrigerant pressure in line 13. Other suitable protective devices, for example, a compressor motor winding temperature sensor, a compressor oil pressure sensor, etc., may be employed with or in substitution of system low and high pressure responsive switches 40, 44, respectively.
Compressor contactor coil 53 is connected in parallel with timer relay 48 through timer switch 32 and lockout switch 60. Cycle timer is connected in parallel with coil 53. Timer 75 controls lockout switch 60, as will be more apparent hereinafter. Lockout switch 60, when moved to the dotted line position of the drawings, closes contact 60' to complete an energizing circuit to signal light 63.
Timer switch 61, when in the solid line position of the drawings, connects timer 35 through system low and high pressure switches 40, 44, respectively, and control relay switch 41 across leads L L Timer switch 61, when moved to the dotted line position, closes contact 61' to place timer 35 in series with timer relay switch 62 across leads L L Timer relay switch 62 is opened by relay 48 upon energization thereof. Timer 35 controls the positions of timer switches 32, 61, as will be more apparent hereinafter.
Referring to FIGURE 3 of the drawings, shaft 74 of disc-like counter 76 is rotatably positioned for movement on a suitable support member 77. Cooperating slot and pin means 78, 79, respectively, limit rotational displacement of counter 76. Counter 76 is provided with a plurality of cylindrical protrusions 80, 81 at spaced intervals circumjacent the circumference thereof. Disc-like drive members 82, 83, operatively arranged adjacent counter 76, have suitable projections 82', 83, respectively, engageable with protrusions 80, 81, respectively, of counter 76 to drive counter 76 in either a clockwise or counterclockwise direction. Drive member 82, driven in a counterclockwise direction by timer 35, moves counter 76 in the direction of the solid line arrow of FIGURE 3 of the drawings. Drive member 83, driven by timer 75 in a clockwise direction, moves counter 76 in the direction shown by the dotted line arrow of FIGURE 3.
Projection 83 of drive member 83 is preferably resilient to prevent jamming or overloading of timer 75 when counter 76 is fully reset. Projection 83 may, for example, be formed from spring steel. As will be more apparent hereinafter, timer '75 is energized concurrently with compressor drive motor 16. During that period, drive member 83, through the inter-engagement of projection 83' with protrusions 81, resets counter 76 to bring pin 79 into abutment with end 78 of slot 78. Since further counterclockwise movement of counter 76 is prevented by slot and pin means 78, 79, resilient projection 83 bends or deforms upon engagement with protrusion 81 and rotation of drive member 83 continues unabated without overload of timer 75. Additionally, the resiliency of projection 83' prevents jamming of the apparatus should drive member projections 82', 83 both simultaneously engage counter 76.
The outer periphery of counter 76 is provided with a plurality of spaced recesses or notches 94 therein. Recesses 94 cooperate with resilient finger 95, fixedly secured to support member 77, to releasably retain counter 76 in each of the several positions defined by each of recesses 94 with finger 95.
Arm 89 of normally closed locking switch 68 is held by suitable bias means (not shown) in contact with the periphery of counter 76. Upon movement of switch arm 89 in recess 84 of counter 76, switch 60 is opened to interrupt the power supply to contactor coil 53 and compressor drive motor 16.
Switch 60 is preferably provided with a resetting control, such as knob 92, necessitating that switch 60 and counter 76 be manually reset prior to any resumption of the compressor operation. Knob 92, drivingly secured to mounting shaft 74, permits manual resetting movement of counter 76 in a counterclockwise direction against the bias of resilient finger 95. Signal light 63 gives visible indication when locking switch 60 is opened.
Timers 35, 75 preferably operate at the same speed. Each revolution of timers 35, 75 moves, by means of drive members 82, 83 respectively, counter 76 a distance equaling the space between the axes of adjacent protrusions 80. The direction of movement of counter 76 may be either clockwise or counterclockwise.
With the several switches of the control circuit diagram in the position shown in FIGURE 2 of the drawings, the refrigeration system is ready to start on a demand for cooling. On a predetermined demand for cooling of the area being conditioned, switch 27 closes to energize control relay 26. Relay 26 closes control relay switches 25 and 41. Switch 25 completes an energizing circuit to the indoor fan motor 23. Switch 41 completes an energizing circuit to outdoor fan motor 22.
Additionally, closure of switch 41 completes a circuit from lead L through system low and high pressure switches 40, 44 respectively, and timer switch 32 to lead 1 L to energize timer relay 48. Timer relay 48 closes timer relay switch 49 to complete the bypass circuit of timer switch 32. A second circuit is completed through control relay switch 41, switches 40, 44 and timer switch 61 to energize timer 35.
Timer 35, after a short interval, moves timer switch 32 to close contact 32' to complete energizing circuits to contactor coil 53 and timer 75. Contactor coil 53 closes contact 19 to complete an energizing circuit to compressor motor 16.
At the expiration of a predetermined timed interval timer 35 moves timer switch 61 to open contact 61" and close contact 61. Since switch 62 is open, timer 35 is deenergized. Drive member 82 of timer 35 is in the position shown in FIGURE 3 of the drawings.
Assuming that energization of the compressor drive motor 16 is maintained for a relatively long period of time, drive member 83 of timer 75 moves, through the interengagement of projection 83 with protrusion 81, counter 76 in a counerclockwise direction shown by the dotted line arrow of FIGURE 3 to bring pin 79 into abutment with end 78' of slot 78. Further movement of counter 76 in a clockwise direction by member 83 is prevented by pin and slot means 78, 79.
Upon satisfaction of the cooling demand imposed upon the system, switch 27 opens to interrupt the energizing circuit to control relay 26 thereby opening switches 25 and 41. Switches 25, 41, when opened, interrupt the energizing circuits to indoor and outdoor fan motors 23, 22, respectively. Switch 41 additionally interrupts the energizing circuit to contactor coil 53 and contact 19 opens to deenergize compressor drive motor 16.
The circuit to timer relay 48 is interrupted. Timer relay 48 opens switch 49 and closes switch 62. Switch 62 completes an energizing circuit through timer switch 61 to timer 35. Following the expiration of a determined timed interval, for example, five minutes, timer 35 moves switch 32 to open contact 32' and close contact 32". Timer 35 is then deenergized.
Drive member 82, operably connected to timer 35, moves, through the interaction of projection 82' with an adjacent counter protrusion 80, counter 76 through one position in a clockwise direction. Counter 76 is now in the solid line position shown in FIGURE 3 of the drawings. The system is now ready to restart upon closure of switch 27.
If, during system operation, one of the switches 40, 44 opens in response to a malfunction as, for example, the opening of switch 44 at a predetermined high system pressure condition, the energizing circuits to contactor coil 53 and timer relay 48 are interrupted and the compressor drive motor 16 is deenergized. Switch 62 closes to energize timer 35. Timer 75 is deenergized. Drive member 82 of timer 35 moves counter 76 in a clockwise direction through one position.
At the close of the determined timed interval, timer 35 moves switch 32 to open contact 32' and close c011- tact 32". The compressor drive motor 16 is restarted in the manner described heretofore.
If, on restarting of compressor drive motor 16, switch 44 reopens, compressor drive motor 16 is again deenergized. Drive member 82 of timer 35 moves counter 76 an additional position in a clockwise direction. Followa ing the occurrence of a preset number of compressor motor deenergizations, switch arm 89 drops into recess 84 of counter 76 to open locking switch 60. Switch 60 opens contact 60 to interrupt the power supply to the compressor contactor coil 53 and closes contact 60" to complete a circuit to signal light 63. To restart the system, the knob 92 must be manually operated to reset counter 76.
It is understood that during each interval in which compressor drive motor 16 is energized, timer 75 is similarly energized. Depending upon the length of time compressor drive motor 16 is energized, drive member 83 of timer 75 may effect movement of counter 76 in a counterclockwise direction in opposition to the movement imparted to counter 76 by drive member 82 of timer 35. Where, however, a sustained malfunction prevails, the period of energization of compressor drive motor 16 is so short that movement of counter 76 by timer 75 is without appreciable effect upon the time required to actuate locking switch 60 and totally deenergize the system.
While I have described and illustrated a preferred embodiment of my invention, it will be understood that my invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.
1. In a refrigeration system including a compressor, the combination of control means operable upon a demand to energize said compressor; condition sensing means operable upon the occurrence of a predetermined malfunction to deenergize said compressor; timing means for preventing reenergization of said compressor by said control means for a timed interval following each deenergization thereof; and means for counting the number of compressor deenergizations responding to a predetermined number of compressor deenergizations for said timed interval to render said control means inoperative.
2. The refrigeration system according to claim 1 in which said counting means includes a member movable in one direction through a preset distance at each deenergization of said compressor, and means adapted to reset said counting means following energization of said compressor, said reset means being arranged to move said counting means member in an opposite direction through said preset distance following energization of said compressor for said timed interval.
3. The refrigeration system according to claim 2 including drive means engageable with said counting means member to move said counting means member in said one direction, said drive means being drivingly secured to said timing means.
4. The refrigeration system according to claim 3 in which said reset means includes a second timing means, and one-way drive means between said counting means member and said second timing means effective upon operation of said second timing means to move said counting means member in said opposite direction.
5. The refrigeration system according to claim 3 in which said counting means includes a switch effective when actuated to prevent energization of said compressor,
said switch including an actuating arm operatively disposed adjacent said counting means member, predetermined movement of said counting means member moving said switch arm to actuate said switch.
6. The refrigeration system according to claim 4 including means for energizing said second timing means in response to energization of said compressor.
7. In a refrigeration system including a compressor the combination of, means controlling energization of said compressor in response to refrigeration system demand; condition sensing means operable upon the occurrence of a predetermined malfunction to deenergize said compressor; means responding to a predetermined number of compressor deenergizations to render said control means inoperative and prevent energization of said compressor including a lockout switch effective when actuated to render said control means inoperable and a switch operator movable in one direction through a predetermined incremental distance at each deenergization of said compressor, said switch operator being adapted to actuate said lockout switch upon movement through a preset number of said incremental distances; resetting means operable upon energization of said compressor for a timed interval to move said switch operator in an opposite direction through said incremental distance; and means adapted following predetermined movement of said switch operator in said opposite direction to render said resetting means inoperable.
8. The refrigeration system according to claim 7 including first timing means adapted to prevent reenergization of said compressor for a predetermined time following each deenergization thereof, said first timing means including a drive member engageable with said switch operator, said drive member being adapted upon operation of said first timing means to move said switch operator in said one direction through said predetermined incremental distance.
9. The refrigeration system according to claim 8 in which said resetting means includes second timing means having a drive member engageable with said switch operator adapted upon operation of said second timing means to move said switch operator in said opposite direction.
References Cited by the Examiner UNITED STATES PATENTS 3,053,057 9/1962 McGrath 62158 3,054,271 9/1962 McGrath 62158 3,135,908 6/1964 Harris.
MEYER PERLIN, Primary Examiner.