Patents Assigned to Plassim Limited
  • Patent number: 4593857
    Abstract: A drip irrigation emitter is located in the wall (IV) of a flexible irrigation pipe. It contains a flow control chamber (15) which communicates with the pipe interior through a filter (II) and with the outside through an outlet passage (17) extending radially through the top portion (11). The chamber (15) is formed by two parallel side walls (20, 20'), a ribbed rear wall (22), and an arched front wall (21) which is incised along its center by a deep channel (23') merging with the arched portion (21) in the shape of two sloping banks (23"). The channel (23') merges at its upper end with the outlet passage (17). Control of the water outflow is made by a thin, rectangular and resilient plate (III) which fits and moves freely between the side walls and is pressed onto the arched front wall (21) by water pressure. Increasing pressure gradually urges the plate onto the banks (23") and into the channel (23'), thereby diminishing the throughflow cross-section and increasing flow resistance.
    Type: Grant
    Filed: November 6, 1984
    Date of Patent: June 10, 1986
    Assignee: Plassim Limited
    Inventor: Dan Raz