| 摘要 |
933,706. Spray-producers. SPEE-FLO MANUFACTURING CORPORATION. Feb. 23, 1961 [March 1, 1960], No. 6735/61. Class 69 (3). An airless spray gun which hydraulically atomizes paint and other liquids has a passage 14 supplied with paint under pressure via a swivel coupling 21 and strainer 19, and when a valve stem 27 is retracted by a trigger 35 the paint flows through a bore 25 and issues from a restricted orifice 43, Fig. 2. The paint flows from the orifice 43 as a jet which is submerged in the paint filling the space between that orifice and the inlet of a coaxial bore 50 in a spray tip 46. Paint enters the spray tip 46 at a considerably lower pressure and considerably higher velocity than those subsisting in the bore 25 and is such that the pressure drop and consequent acceleration through the nozzle opening 61 are not great enough to produce an appreciable " vena contracta," and the spray spreads uniformly away from the nozzle opening. The latter is located in a boss 55, and is formed by a transverse tapered slot 59 which cuts across the spherically-shaped end of the bore 50 to provide an oval-shaped outlet 61 having its long dimension equal to the diameter of the bore 50 and a short dimension equal to the minimum width of the tapered slot 59. A spray of fan-shaped cross-section is thereby provided. In the embodiment of Fig. 6 the restricted orifice 143 is located in a separate plate 170; in Fig. 7 the restricted orifice 243 is located in a part 271 protruding from a disc 270 and engaging within the nozzle tip 246. In the modification of Fig. 8 a restricted orifice is not provided, and the paint issues as a submerged jet from a bore 341, and the pressure therein is restricted to atmosphere by removing excess paint via passages 373, 375 and hose 376 which is connected to the input of a pump. The spray tips such as 37, Fig. 1, of the guns described may be replaced by others with orifices 43 of different sizes. |
