Patents by Inventor Hans Dieter Grasshoff

Hans Dieter Grasshoff 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).

  • Liquid composition and its use as magneto-rheological liquid
    Patent number: 6245253
    Abstract: There are provided fluid compositions with particulate solid materials dispersed therein which are characterized by exceptionally low settling tendencies of the dispersed particles. Such compositions containing particulate ferromagnetic solids are useful as magnetorheological fluids.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: June 12, 2001
    Assignee: RWE-DEA Aktiengesellschaft fuer Mineraloel und Chemie
    Inventors: Hans-Dieter Grasshoff, Dietrich Pirck
  • Synthetic ester lubricants for refrigerator systems
    Patent number: 5830833
    Abstract: Lubricants for refrigeration equipment operating with fluorocarbons as refrigerants are produced by esterification of at least one neopolyol type polyhydric alcohol with an acid component comprising 60 to 80 mol percent n-pentanoic acid, from about 40 to about 10 mol percent of at least one straight chain C.sub.6 to C.sub.10 monocarboxylic acid and from about 0 to about 30 mol percent C.sub.6 to C.sub.10 branched chain monocarboxylic acid. The resulting esters are suitable for use without lubricating oil additives.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: November 3, 1998
    Assignee: RWE-DEA Aktiengesellschaft fur Mineraloel und Chemie and Texaco Deutschland GmbH
    Inventors: Hans Dieter Grasshoff, Vladislav Synek, Harald Kohnz
  • Homogeneous electroviscous fluids using aluminum compounds
    Patent number: 5800731
    Abstract: Homogeneous, electro-viscous fluids are provided which contain aluminum soaps based on products obtained by reacting one or more mono- or polycarboxylic acid(s) or the anhydrides or semi-esters thereof with reactive aluminum compounds, such as aluminum alcoholates. The aforesaid fluids manifest high electro-rheological effect and are completely homogeneous, and do not require a dispersant.
    Type: Grant
    Filed: June 11, 1996
    Date of Patent: September 1, 1998
    Assignee: RWE-DEA Aktiengesellschaft fur Mineraloel und Chemie
    Inventors: Dietrich Pirck, Hans-Dieter Grasshoff, Harald Kohnz, Peter Finmans, Tobias Carstensen, Dieter Jakubik, Wilfried Weber, Dieter Winkler
  • Non-polluting shock absorber and level controller fluids
    Patent number: 5474714
    Abstract: The present invention relates to hydraulic fluids which are particularly intended for shock absorption and level controlling applications in vehicles. Hydraulic fluids are provided which substantially consist of esterification products of monosaturated fatty acids and 2-alkyl-1-alkanols. The claimed fluids comply with the requirements made on industrial hydraulic media and are particularly outstanding by their good biodegradability.
    Type: Grant
    Filed: July 22, 1994
    Date of Patent: December 12, 1995
    Assignee: RWE-DEA Aktiengesellschaft fur Mineraloel und Chemie
    Inventors: Dietrich Pirck, Hans-Dieter Grasshoff
  • Biodegradable grease composition
    Patent number: 4115282
    Abstract: A biodegradable lubricating grease composition is provided comprising an emulsion of vegetable-derived gel, water and a lubricant from the class of natural oils and fats.
    Type: Grant
    Filed: November 24, 1976
    Date of Patent: September 19, 1978
    Assignee: Deutsche Texaco Aktiengesellschaft
    Inventor: Hans Dieter Grasshoff
  • Lithium soap lubricating grease
    Patent number: 3988248
    Abstract: A grease which has improved stability at high temperature is provided by incorporating in an otherwise conventional grease a lithium soap of a hydroxy-stearic acid and an alkali borate. The grease is made by adding lithium tetraborate directly to a mixture comprising a lithium soap of a hydroxy-fatty acid and lubricating oil wherein the resulting mixture has from about 5 to 20 percent by weight of the lithium soap and from about 0.1 to 3 percent by weight of lithium tetraborate.
    Type: Grant
    Filed: March 17, 1975
    Date of Patent: October 26, 1976
    Assignee: Deutsche Texaco Aktiengesellschaft
    Inventor: Hans Dieter Grasshoff