Refrigeration mechanical diagnostic protection and control device

Abstract

In vapor compression refrigeration systems a mechanism and method are provided for protecting a compressor from failures related to lack of superheat, loss of lubricating oil and other system malfunctions. Also provided is a mean of monitoring system conditions and providing service personnel with a quick manner of diagnosing problems.

1 . A cooling system including a compressor, a condenser having a fan motor and a heat exchange coil, and an evaporator with refrigerant flowing through the system, an outside ambient temperature sensor for determining outside ambient temperature, and a device for constantly calculating sub-cooling of the refrigerant and determining when the sub-cooling is below a predetermined level at a given ambient temperature, and generating a signal representative of the determined sub-cooling.  
   
   
       2 . A cooling system as in  claim 1  including cooling means for lowering the temperature of the refrigerant when the determined sub-cooling is below the predetermined level.  
   
   
       3 . A cooling system as in  claim 2  wherein the cooling means is water spray onto the heat exchange coil of the condenser.  
   
   
       4 . A cooling system as in  claim 2  wherein the cooling means is an air flow onto the heat exchange coil of the condenser.  
   
   
       5 . A cooling system as in  claim 1  including a fan limiting device constructed and arranged to cycle the condenser fan motor at ambient temperatures below a predetermined level to thereby maintain a substantially constant pressure on the refrigerant flowing through the cooling system.  
   
   
       6 . A cooling system as in  claim 5  wherein the predetermined temperature level is within the range of 60° to 70° F.  
   
   
       7 . A cooling system as in  claim 5  including a device for determining pressure of the refrigerant flowing through the cooling system and for deenergizing the compressor when the refrigerant pressure drops below a predetermined level.  
   
   
       8 . A cooling system as in  claim 7  wherein the device for deenergizing the compressor when the refrigerant drops below a predetermined level also deenergizes the compressor when the refrigerant pressure is above a predetermined level.  
   
   
       9 . A cooling system as in  claim 8  including a display of refrigerant temperature and pressure.  
   
   
       10 . A cooling system as in  claim 7  including a device for determining superheat of the refrigerant and for deenergizing the compressor when the superheat drops below a predetermined level.  
   
   
       11 . A cooling system as in  claim 10  including display means for indicating a low superheat warning within a range slightly above the predetermined level below which the compressor is deenergized.  
   
   
       12 . A cooling system as in  claim 11  including a display for indicating satisfactory superheat, superheat warning and superheat failure.  
   
   
       13 . A cooling system including a compressor, a condenser having a fan motor and an exvaporator with refrigerant flowing through the system, an outside ambient temperature sensor for determining outside ambient temperature, and a fan limiting device constructed and arranged to cycle the condenser fan motor at ambient temperatures below a predetermined temperature level to thereby maintain a substantially constant pressure on the refrigerant flowing through the cooling system.  
   
   
       14 . A cooling system as in  claim 13  wherein the predetermined temperature level is within the range of 60° to 70° F.  
   
   
       15 . A cooling system as in  claim 13  including a device to determine pressure of the refrigerant flowing through the cooling system and to deenergize the compressor when the refrigerant pressure drops below a predetermined level.