Patents by Inventor Lourens A. V. Hiemstra

Lourens A. V. Hiemstra 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: 4915312
    Abstract: A sprinkling device for liquids comprises an emitter tube 18 of resiliently flexible material having a mounted inlet end 24.1 and an unmounted outlet end 24.2, the arrangement being such that, with liquid flowing at a sufficient rate through the emitter tube, hydraulic forces exerted by the flowing liquid on the tube cause the outlet end continuously to move about. The emitter tube is mounted on a fitting 16 which has a flow passage 34 therethrough which leads into the emitter tube, the flow passage having, at its inlet end, a pair of grooves 36 which lead tangentially into the flow passage. These tangentially arranged grooves impart a swirling motion to water entering the emitter tube. A pop-up sprinkler is also disclosed in which the emitter tube is mounted on a plunger which is displaceable in a barrel, the emitter tube protruding through an opening at the end of the barrel.
    Type: Grant
    Filed: July 29, 1988
    Date of Patent: April 10, 1990
    Assignee: Silkbell Ltd.
    Inventor: Lourens A. V. Hiemstra
  • Patent number: 4856552
    Abstract: A flow regulating device comprises a chamber forming element covered by a tube of elastomeric material, which together form a flow passage leading from an inlet port to an outlet port. The flow passage forms a first flow chamber which is partly defined by the elastomeric tube and which is configured such that flow of fluid through the chamber causes inward deflection of the tube and thus constricts the flow cross section of the first flow chamber. The flow passage further forms a second flow chamber downstream of the first flow chamber, the second flow chamber being partly defined by the elastomeric tube, and the configuration being such that flow of fluid through the second flow chamber causes the tube to deflect inwardly and thus constrict the flow cross section of the second flow chamber. In one embodiment the arrangement is such that vortex flow is induced in each of the flow chambers.
    Type: Grant
    Filed: November 10, 1987
    Date of Patent: August 15, 1989
    Assignee: Silkbell Limited
    Inventor: Lourens A. V. Hiemstra