Pressure relief - and emptying valve for injection molding, which is under air pressure signal containing flue as a function of the container, in operation of injection pressure differential

摘要

963,912. Forcing liquids by gaseous pressure. ROOT-LOWELL MANUFACTURING CO. Aug. 25, 1961 [Oct. 27, 1960; Feb. 17, 1961], No. 30794/61. Heading F1R. [Also in Divisions F2 and E2] A compression sprayer comprises a spray solution tank with an air pressure pump therein, a grommet for sealing the discharge tube projecting through an opening in the tank or a seal at the fill opening in the tank head, the seal or grommet being subjected to the air pressure in the tank. A dish-shaped head 17, Figs. 2 and 3, of a tank 10 has a fill opening 18 around which an annular locking clip 22 is secured at its flange 21 by bending over a flange 19 of the head 17. A member 26, pressfitted into a pump cylinder 29, has slots 30 with radial notches 31 into which fingers 36, with radial lips 37, may be guided against the action of a spring 51. Then, on clockwise rotation of the plunger shaft 33, the lips abut the underside of the member 26 and each finger 36 abuts one end of one slot 30, so that on further clockwise rotation the member 26 also rotates and thereby engages its upper and inclined surfaces 48 (see Fig. 10) with the undersides of the circumferentially spaced lips 24 on the locking clip 22. The member 26 is thereby screwed into the clip 22 until it abuts stops (not shown) at the ends of the lips 24 and projections 49 of the member 26 are forced against a seal 38 to effect sealing. Fig. 2 shows the pump assembly in the released position preparatory to removal. Increases in air pressure within the tank 10 further increase the sealing by the action of the pressure on the lips 44 and 45 of the seal 38. A grommet 53 is provided around a discharge tube 12 which is preferably flexible and leads to a metal or rigid tube 14 having an adjustable spray nozzle 15 and a manually operated control valve (not shown). The grommet 53 is shown resting on projections 57 in which position there is a passage between the interior of the tank 10 and the atmosphere. However, when a positive pressure exists in the tank, the grommet is forced upwardly to engage its tapered portion with the hole 54 and thereby seals off this passage. In addition, the pressure within the tank improves the sealing between the grommet and the pipe 12. The pressure in the tank 10 may be released by pushing the grommet 53 downwards on to its projections 57, thereby opening the passage to the atmosphere. Additionally, any liquid remaining in the tank 10 may be drained through this passage. An alternative form of grommet, Fig. 12, has serrations which engage substantially similar serrations 71 on the plastic discharge pipe 12a. Sealing is effected by engagement of a tapered portion 59 located below an annular recess 73 and by the action of the air pressure on a lip 75.