GB864241A - An injector assembly for injecting a liquid fertilizer into an irrigation system - Google Patents

Abstract

864,241. Mixing liquids in flow. FUNK, L. D. June 28, 1957, No. 20550/57. Class 86 [Also in Group XXVIII] An apparatus for injecting liquid fertilizer from a pipe 18, Fig. 3, into water flowing through an irrigation conduit 10, 12, Fig. 1, comprises a variable capacity reciprocating pump 16 driven at constant speed by an electric motor 22 through a gear in a casing 148, a crank arm 150, a connecting rod 146, a crank arm 142, a vertically adjustable crank shaft 138, a crank lever 136, a plate 132 pivoted on a slide block 126 and a rod 40, and a piston 178 in a device 14 operable by the flow of water automatically to vary the stroke of the pump 16 and also control the actuation of the motor 22. As shown in Fig. 4, the piston 178 slidable in a perforated cylindrical partition 163 within an enlarged portion 161 of the device 14, the partition 163 being substantially the same diameter as the conduits 10, 12 and the perforations 167 being arranged in a spiral. The piston rod 176 is connected to a lug 186 having arms 188, 190 slidable in guide slots 182, and the lug is pivotably connected at 192, Fig. 3, to an adjusting member 140 slidable in a fixture 160 and pivotally secured at its upper end to the crank shaft 138. The piston 178 will thus adopt a position dependent on the rate of flow of water through the conduits 10, 12 and will vary the vertical positioning of the shaft 138. The crank arm 136 is slidable between rollers 134 on the plate 132 which is pivotal on a pin securing the block 126 to the rod 40 so that the effective length of the arm 136 is varied by the piston 178 and consequently the stroke of the rod 40 is also varied. The rod 40 constitutes one piston rod of the pump 16, the other piston rod 42 being operable by the rod 40 through an adjustable cross-head 48, 50, 52, 54 of which the cross-arms 52, 54 are secured to the rods 40, 42 by set screws 58. Referring to Fig. 11 the pump 16 comprises opposed pump cylinders 32, 34 connected respectively by passages 64, 66, with transverse bores 60, 62. The bottoms of the bores 60, 62 are connected by passages 92, 94 with the liquid fertilizer supply pipe 18 whilst the tops of the bores are connected by passages 74, 76 to a nipple 72 connected by a pipe 20, Fig. 3, to the conduit 12. Each bore has a lower intake valve sleeve 80 with an intake valve 86 seated by a spring 88 and the sleeve 80 connects by a port 110 with an upper discharge valve sleeve 100 the discharge valve 106 of which is seated by a spring 108. If for example the rod 40, Fig. 11, moves to the right its piston 44 will expel liquid from the cylinder 32 through the left-hand discharge valve 106, passage 74, nipple 72 and pipe 20 to the conduit 12. At this time the piston 46 of the rod 42 also moves to the right and fertiliser liquid is drawn in from the pipe 18, passage 94 and right-hand intake valve 86. During this time the left-hand intake valve 86 and the right-hand discharge valve are seated. When the pistons 46, 44 move to the left, the liquid is drawn through the passage 92 and discharged through the passage 76, the left-hand discharge valve and the right-hand intake valve then being seated. The arm 190 on the piston rod 176 operates a switch 24 to start the electric motor 22 when the water flow exceeds a predetermined rate. In order to ensure that the rate of injection is positively reduced as the rate of flow of water decreases, the top of the member 140 engages a plunger 210 slidable in a cylinder 202 connected by a pipe 216 with that side of the device 14 connected to the conduit 10. Since the diameter of the plunger 210 is smaller than that of the piston 178 the latter can easily overcome the downward pressure on the plunger 210 when the piston moves upwardly. However when the water flow drops below a predetermined value the plunger 202 will produce a constant downward force to restore the member 140 to its lowered position and stop the motor.