Composition and methods for injection of sealants into air conditioning and refrigeration systems

Abstract

The use of sealants based on organosilanes for refrigeration and air conditioning systems is made possible by control of the rate of introduction and viscosity of the sealant mixture within certain ranges. An appropriate choice of organosilane sealant is made to allow effective sealing of small pinhole size leaks in the air conditioning or refrigeration system. The organosilane is then combined with a miscible lubricant at particular ratios to provide the proper mixture viscosity for injection into the refrigerant system to prevent bearing seizure. Specific orifice sizes are selected for an apparatus to ensure that the composition is injected at the flow rates required to prevent liquid slugging and subsequent compressor shutdown or failure. In addition, effective introduction of the mixture requires certain procedures be performed. Injection procedures are also described that prevent temporary or catastrophic equipment shutdown.

We claim: 
     
         1 . A method for injecting sealant comprising:
 injecting a sealant mixture comprising an organosilane sealant into a low pressure side of a charged air conditioning or refrigeration system having a compressor, high pressure side, and low pressure side, while running the charged air conditioning or refrigeration system, and while controlling a flow rate for injecting the sealant mixture into the system below a maximum flow rate of 6% per minute of total lubricant content of the charged air conditioning or refrigeration system.   
     
     
         2 . The method of  claim 1  wherein the viscosity of the mixture is not less than 7 CST when measured at 40° C. 
     
     
         3 . The method of claim I wherein the maximum flow rate is 6 cc/sec or less. 
     
     
         4 . The method of  claim 1 , wherein the organosilane is a monomer capable of forming a solid polymer with itself or other chosen organosilanes in the presence of moisture, and is stable in the absence of moisture, and does not substantially interfere with the normal operation of other contents of the system in selected quantities. 
     
     
         5 . The method of  claim 1 , wherein the mixture further comprises a lubricant. 
     
     
         6 . The method of  claim 5 , wherein the viscosity of the mixture is not less than 7 CST when measured at 40° C. 
     
     
         7 . The method of  claim 1 , further comprising, prior to injection, fluidly connecting a vessel containing the sealant mixture to the low-side. 
     
     
         8 . The method of  claim 7 , further comprising pressurizing the sealant mixture sufficiently above system low side operating pressure to cause the sealant mixture to enter the system from the vessel when the system is running. 
     
     
         9 . The method of  claim 7 , further comprising, after connection of the vessel and prior to injection, pressurizing the sealant mixture using system pressure of the system in a non-running state to pressurize the sealant mixture in the vessel sufficiently above system low side operating pressure to cause the sealant mixture to enter the system from the vessel when the system is running. 
     
     
         10 . The method of  claim 8 , further comprising allowing the sealant mixture to cool to near ambient temperature after the vessel is pressurized and while the vessel is fluidly connected to the system in the non-running state. 
     
     
         11 . The method of  claim 9  further comprising turning off the charged air conditioning or refrigeration system and allowing system pressure to equalize, and using the equalized system pressure for pressurizing the sealant mixture. 
     
     
         12 . The method of  claim 10  further comprising turning off the charged air conditioning or refrigeration system and allowing system pressure to equalize, and using the equalized system pressure for pressurizing the sealant mixture. 
     
     
         13 . The method of  claim 12 , wherein the sealant mixture has a viscosity above 7 cst. when measured at 40° C. 
     
     
         14 . The method of  claim 13 , wherein the maximum controlled rate is 6 cc/sec. 
     
     
         15 . The method of  claim 7 , wherein the step of connecting the vessel to the system comprises connecting a hose assembly between the vessel and a low pressure side service port of the system. 
     
     
         16 . The method of  claim 15 , comprising substantially evacuating the hose assembly prior to connection to the system. 
     
     
         17 . The method of  claim 1 , wherein injecting includes passing the mixture through a fixed diameter orifice prior to entering the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         18 . The method of  claim 1 , wherein injecting includes passing the mixture through a fixed diameter orifice between the vessel and the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         19 . The method of  claim 4 , wherein injecting includes passing the mixture through a fixed diameter orifice prior to entering the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         20 . The method of  claim 4 , wherein injecting includes passing the mixture through a fixed diameter orifice between the vessel and the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         21 . The method of  claim 6 , wherein injecting includes passing the mixture through a fixed diameter orifice prior to entering the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         22 . The method of  claim 6 , wherein injecting includes passing the mixture through a fixed diameter orifice between the vessel and the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         23 . The method of  claim 1  wherein injecting further comprises injecting the sealant mixture including a quantity of organosilane that reduces the final lubricant viscosity by no more than 10% once the organosilane has been distributed throughout the system. 
     
     
         24 . The method of  claim 23  wherein the viscosity of the mixture is not less than 7 CST when measured at 40° C. 
     
     
         25 . The method of  claim 24  wherein the maximum flow rate is 6 cc/sec or less. 
     
     
         26 . The method of  claim 25 , wherein the organosilane is a monomer capable of forming a solid polymer with itself or other chosen organosilanes in the presence of moisture, and is stable in the absence of moisture, and does not substantially interfere with the normal operation of other contents of the system in selected quantities. 
     
     
         27 . The method of  claim 26 , wherein the mixture further comprises a lubricant. 
     
     
         28 . The method of  claim 27 , further comprising, prior to injection, fluidly connecting a vessel containing the sealant mixture to the low-side. 
     
     
         29 . The method of  claim 28  further comprising pressurizing the sealant mixture sufficiently above system low side operating pressure to cause the sealant mixture to enter the system from the vessel when the system is running. 
     
     
         30 . The method of  claim 29 , further comprising, after connection of the vessel and prior to injection, pressurizing the sealant mixture using system pressure of the system in a non-running state to pressurize the sealant mixture in the vessel sufficiently above system low side operating pressure to cause the sealant mixture to enter the system from the vessel when the system is running. 
     
     
         31 . The method of  claim 30 , further comprising allowing the sealant mixture to cool to near ambient temperature after the vessel is pressurized and while the vessel is fluidly connected to the system in the non-running state. 
     
     
         32 . The method of  claim 31  further comprising turning off the charged air conditioning or refrigeration system and allowing system pressure to equalize, and using the equalized system pressure for pressurizing the sealant mixture. 
     
     
         33 . The method of  claim 32 , wherein the step of connecting the vessel to the system comprises connecting a hose assembly between the vessel and a low pressure side service port of the system. 
     
     
         34 . The method of  claim 33 , comprising substantially evacuating the hose assembly prior to connection to the system. 
     
     
         35 . The method of  claim 23 , wherein injecting includes passing the mixture through a fixed diameter orifice prior to entering the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         36 . The method of  claim 23  wherein injecting includes passing the mixture through a fixed diameter orifice between the vessel and the system, the orifice having an opening within a range of from 0.02-0.06 inches. 
     
     
         37 . The method of  claim 4  wherein injecting further comprises injecting the sealant mixture including a quantity of organosilane that reduces the final lubricant viscosity by no more than 10% once the organosilane has been distributed throughout the system. 
     
     
         38 . The method of  claim 6  wherein injecting further comprises injecting the sealant mixture including a quantity of organosilane that reduces the final lubricant viscosity by no more than 10% once the organosilane has been distributed throughout the system. 
     
     
         39 . A device for introducing sealant into a hermetically sealed charged air conditioning or refrigeration system, the device comprising:
 a sealed vessel comprising an organosilane mixture of an organosilane and a miscible material, the mixture having a viscosity above 7 cst. when measured at 40° C., the organosilane mixture comprising a quantity of organosilane that in combination with existing system contents reduces lubricant viscosity of the system by no more than 10%, and wherein, the organosilane is a monomer or oligomer capable of forming a solid polymer with itself or other chosen organosilanes in the presence of moisture, and is stable in the absence of moisture in the system, and does not substantially interfere with the normal operation of contents of the system in selected quantities.   
     
     
         40 . The device of  claim 39  further comprising a metering device for fluid connection with the sealed vessel, and for controlling fluid flow from the sealed vessel. 
     
     
         41 . The device of  claim 40  wherein the metering device is an orifice having an opening within a range of from 0.020-0.06 inches. 
     
     
         42 . The device of  claim 41  further comprising a fitting for sealed fluid connection to a low side port of the system, and wherein fluid flowing through the metering device also flows through the fitting. 
     
     
         43 . The device of  claim 39  further comprising a hose assembly with a first fitting for sealed fluid connection to a low side port of the system, and a sealed fluid connection to the sealed vessel. 
     
     
         44 . The device of  claim 43  further comprising a metering device for controlling fluid flow from the sealed vessel through the hose assembly. 
     
     
         45 . The device of  claim 44  wherein the fluid connection to the sealed vessel is a second fitting. 
     
     
         46 . The device of  claim 45  wherein the second fitting comprises a manually operable valve for providing fluid connection between the hose assembly and the sealed vessel. 
     
     
         47 . The device of  claim 46  wherein the second fitting further comprises a can-tapper for opening the sealed vessel. 
     
     
         48 . The device of  claim 47  wherein a filter is placed between the fitting connecting to the system and the metering device. 
     
     
         49 . The device of  claim 48  wherein the metering device is an orifice having an opening with a diameter of 0.06 inches or less.