Patents by Inventor John C. Tolfa

John C. Tolfa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8778859
    Abstract: Polymeric additives are disclosed for compressor lubricants which can reduce the tendency of the lubricant to become entrained in compressed gases and be carried forward as fine dispersed droplets in compressed gas systems such as compressed air, natural gas, and compression refrigeration systems.
    Type: Grant
    Filed: October 1, 2003
    Date of Patent: July 15, 2014
    Assignee: The Lubrizol Corporation
    Inventors: Thomas E. Rajewski, Kenneth C. Lilje, John C. Tolfa
  • Patent number: 6677284
    Abstract: A problem with refrigeration systems using ammonia as the refrigerant and hydrocarbon lubricants is that the seals/gaskets of the systems have a tendency to harden and shrink. This can cause leakage of the refrigerant and eventually require disassembly of the equipment and replacement of the seals. The addition of a small amount polyether having an aromatic fragment of 6-18 carbon atoms or an aliphatic fragment of 10-22 carbon atoms can soften the seals and partially re-swell the seals solving the leakage problem and avoiding expensive maintenance costs. Alternatively a polyether of 1,2-butylene oxide which is more oil soluble than most other polyethers with a smaller Z group e.g. derived from alkanols of 1 to 9 carbon would be effective at reducing hardening and shrinkage.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: January 13, 2004
    Assignee: The Lubrizol Corporation
    Inventors: Thomas Rajewski, John C. Tolfa, Hsinheng Li
  • Publication number: 20030104951
    Abstract: A problem with refrigeration systems using ammonia as the refrigerant and hydrocarbon lubricants is that the seals/gaskets of the systems have a tendency to harden and shrink. This can cause leakage of the refrigerant and eventually require disassembly of the equipment and replacement of the seals. The addition of a small amount polyether having an aromatic fragment of 6-18 carbon atoms or an aliphatic fragment of 10-22 carbon atoms can soften the seals and partially re-swell the seals solving the leakage problem and avoiding expensive maintenance costs. Alternatively a polyether of 1,2-butylene oxide which is more oil soluble than most other polyethers with a smaller Z group e.g. derived from alkanols of 1 to 9 carbon would be effective at reducing hardening and shrinkage.
    Type: Application
    Filed: August 29, 2002
    Publication date: June 5, 2003
    Inventors: Thomas Rajewski, John C Tolfa, Hsinheng Li
  • Patent number: 6267907
    Abstract: A lubricant-refrigerant composition for a compression refrigeration system is disclosed which comprises (A) carbon dioxide refrigerant, and (B) a lubricant of an aliphatic naphthalene. A supplemental lubricant comprising at least one alkyl benzene, a hydrocarbon, a polyalkylene glycol, a polyol ester or a polyvinyl ether may also be present. Additionally, a performance additive comprising an alkoxylated alcohol or phenol, an alkoxylated glycol, an alkyl phenol or a phosphorus compound may also be present.
    Type: Grant
    Filed: June 3, 1999
    Date of Patent: July 31, 2001
    Assignee: The Lubrizol Corporation
    Inventors: John C. Tolfa, Thomas E. Rajewski
  • Patent number: 6127324
    Abstract: The present invention relates to a lubricating basestock comprising a blend of (A) at least one polyalkylene glycol and (B) at least one alkyl aromatic. Additives, such as antioxidants, corrosion inhibitors, and metal deactivators, can be added to the lubricating basestock. In one embodiment, the lubricating composition is free of naphthol. The blend can also be used in combination with a variety of oils of lubricating viscosity, with or without additives therein. According to the present invention, the lubricating composition exhibits excellent oxidation and thermal stability, demulsibility, and hydrolytic stability. The lubricating composition is particularly useful as a positive displacement compressor lubricant.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: October 3, 2000
    Assignee: The Lubrizol Corporation
    Inventors: John C. Tolfa, Kenneth C. Lilje