Ammonia refrigeration compressor and transfer pump lubricating oil based on alkylated naphthalenes

Abstract

A lubricant composition comprising an alkylated naphthalene component and a mineral oil component and which is essentially free of ammonia reactive components is described. In certain examples, the lubricant composition is food grade. The lubricant compositions are particularly well suited for use in ammonia refrigeration compressors and ammonia refrigerant transfer pumps. The mineral oil has no more than about 60 percent of paraffinic compounds by weight of the mineral oil. When used to lubricate ammonia refrigeration compressors, the lubricant composition has an ISO VG of 46 to 100. When used to lubricate ammonia refrigerant transfer pumps, the lubricant composition has an ISO VG of 22 to 46.

What is claimed is: 
     
         1 . A method of lubricating an ammonia refrigeration compressor or ammonia refrigerant transfer pump having a lubricant circuit and a refrigerant circuit, the method comprising:
 charging the refrigerant circuit with ammonia;   charging the lubricant circuit with a lubricant composition that comprises an alkylated naphthalene component.   
     
     
         2 . The method of  claim 1 , wherein the alkylated naphthalene component is at least about 25 percent by weight of the lubricant composition. 
     
     
         3 . The method of  claim 1 , wherein the lubricant composition further comprises a mineral oil component. 
     
     
         4 . The method of  claim 3 , wherein the mineral oil is no more than about 75 percent by weight of the lubricant composition. 
     
     
         5 . The method of  claim 3 , wherein the mineral oil component comprises no more than about 60 percent of paraffinic compounds by weight of the mineral oil component. 
     
     
         6 . The method of  claim 1 , wherein the lubricant composition is essentially free of ammonia reactive compounds. 
     
     
         7 . The method of  claim 1 , wherein the lubricant composition has an ISO VG of no more than about 100. 
     
     
         8 . The method of  claim 1 , wherein the lubricant composition further comprises:
 an effective amount of at least one antioxidant;   an effective amount of at least one corrosion inhibitor; and   an effective amount of at least one antifoam agent.   
     
     
         9 . The method of  claim 1 , wherein the lubricant composition further comprises:
 about 0.25 percent to 0.50 percent of at least one aromatic amine antioxidant by weight of the lubricant composition;   about 0.25 percent to 0.50 percent of at least one phenolic antioxidant by weight of the lubricant composition;   about 0.05 percent to 0.10 percent of at least one corrosion inhibitor by weight of the lubricant composition; and   about 200 parts per million (ppm) of at least one polymeric antifoam additive by weight of the lubricant composition.   
     
     
         10 . The method of  claim 1 , wherein the lubricant composition is food-grade. 
     
     
         11 . The method of  claim 1 , wherein the lubricant composition further comprises a food-grade, white mineral oil having an aromatic compound content of less than about one percent by weight of the white mineral oil. 
     
     
         12 . The method of  claim 1 , wherein the lubricant composition consists essentially of:
 at least about 25 percent of the alkylated naphthalene component by weight of the lubricant composition;   at least about 20 percent of a mineral oil component by weight of the lubricant composition, wherein the mineral oil component has a paraffin content of no more than about 60 percent by weight of the mineral oil component;   an additive package consisting essentially of an effective amount of at least one antioxidant, an effective amount of at least one corrosion inhibitor, and an effective amount of at least one anti-foam agent, wherein the lubricant composition has a kinematic viscosity of no more than about 100 centistokes at 40° C.   
     
     
         13 . A lubricant composition, comprising:
 at least about 25 percent of an alkylated naphthalene component by weight of the lubricant composition; and   at least about five percent of a mineral oil component by weight of the lubricant composition, wherein the lubricant composition is essentially free of ammonia reactive components.   
     
     
         14 . The lubricant composition of  claim 13 , wherein the alkylated naphthalene component is about 45 percent by weight of the lubricant composition and the mineral oil component is about 55 percent by weight of the lubricant composition. 
     
     
         15 . The lubricant composition of  claim 13 , wherein the mineral oil component includes no more than about 60 percent of paraffinic compounds by weight of the mineral oil component. 
     
     
         16 . The lubricant composition of  claim 13 , wherein the lubricant composition has an ISO VG of no more than about 100. 
     
     
         17 . The lubricant composition of  claim 13 , consisting essentially of the alkylated naphthalene component, the mineral oil component, and an additive package, wherein the additive package consists essentially of an effective amount of at least one antioxidant, an effective amount of at least one corrosion inhibitor, and an effective amount of at least one anti-foam agent. 
     
     
         18 . The lubricant composition of  claim 13 , further comprising:
 about 0.25 percent to 0.50 percent weight percent of at least one aromatic amine antioxidant by weight of the lubricant composition;   about 0.25 percent to 0.50 percent weight percent of at least one phenolic antioxidant by weight of the lubricant composition;   about 0.05 percent to 0.10 percent weight percent of at least one corrosion inhibitor by weight of the lubricant composition; and   about 200 parts per million (ppm) of a polymeric antifoam additive by weight of the lubricant composition.   
     
     
         19 . The lubricant composition of  claim 13 , wherein the lubricant composition is food grade, and the mineral oil component is a food-grade, white mineral oil with an aromatic compound content of not more than about one percent by weight of the mineral oil. 
     
     
         20 . The lubricant composition of  claim 13 , wherein the alkylated naphthalene component is about 45 percent by weight of the lubricant composition, the mineral oil component is about 55 percent by weight of the lubricant composition, the mineral oil component includes no more than about 60 percent of paraffinic compounds by weight of the mineral oil component and less than about one percent of aromatic compounds by weight of the mineral oil component, the lubricant composition has an ISO VG of no more than 100 and includes an additive package that consists essentially of an effective amount of at least one antioxidant, an effective amount of at least one corrosion inhibitor, and an effective amount of at least one anti-foam agent.