Patents Assigned to Silkbell Limited
  • Patent number: 7140557
    Abstract: The invention provides an emitter tube for an irrigation system, the tube being of resiliently flexible material having a base inlet end adapted to be mounted and a free outlet end adapted to be unmounted, 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, further having a base section and an end section downstream from the base section when the end section is of greater flexibility than the base section.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: November 28, 2006
    Assignee: Silkbell Limited
    Inventor: Christoffel Theron
  • 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