Patent GB-787774-A (GB)
Title: Improvements relating to immersion apparatus
IPC: B06B1/18
Filed: 1955-10-19
Abstract: 787,774. Compressed-air engines; valve gear. MAGNUS CHEMICAL CO., Ltd. (Magnus Chemical Co., Inc.). Oct. 19, 1955, No. 29837/55. Classes 122 (2) and 122 (3). A compressed air motor for actuating immersion apparatus of the kind in which articles to be treated, for example metallic elements requiring cleansing, pickling, &c., are supported by a carrier reciprocated in a liquid, comprises a piston 2 connected to the carrier and reciprocable in a verticallydisposed cylinder 5 having a lower port 4 and an upper port 5, and control means for alternately admitting compressed air to and venting it from the lower port, the control means being actuated to the position in which the lower port is vented by compressed air supplied through the upper port. The ports 4 and 5 are respectively connected to ports 10 and 17 in a housing 6 for a spool valve 7 urged to its upper position by a spring 16. The housing has also an inlet port 12 connected by a line 13 to a source A of compressed air, an exhaust port 15 connected to atmosphere and an end port 18 connected to a three-way valve 21 by which the lower end of the housing may be either vented or connected to the source A through a line 22. In the position shown in Fig. 1, air admitted to the cylinder 3 below the piston lifts the latter until it over-runs the port 5. Compressed air then passes through the line 19 and port 17 and forces the valve 7 down to its lower position, thereby closing inlet port 12 and opening exhaust port 15 to vent the underside of the piston which then descends due to gravity. When the piston uncovers port 5 the space above the valve 7 is vented, via the cylinder, and the valve is returned to its original position by the spring 16 to recommence the cycle. If the three-way valve 21 is turned to its alternative position, the underside of the valve 7 is subjected to the air pressure and uncovering of the port 5 by the piston in its upward movement no longer reverses the valve 7 so that the piston continues to rise until positively arrested by a stop 27. In a modification, Fig. 4 (not shown), the port 18 is open to atmosphere and the valve 21 is arranged in the line 19 so that the port 17 may be connected either to the port 5, when the piston reciprocates as described for Fig. 1, or vented to atmosphere, when the piston moves continuously upward until arrested by the stop 27. In another modification, Fig. 7, the upper port 65 is connected to the line 79 by parallel pipes 83 and 85 having therein a check-valve 84 and a shut-off valve 86 respectively. A third port 87, above port 65, is also connected to line 79 via a line 88 and check valve 89. With the valve 86 open and the valve 81 in the position shown, the operation is the same as that described for Fig. 1 since pressure air in the line 85 cannot escape through line 88 due to the valve 89 closing and the piston reciprocates between positions a little above and below the port 65. If the valve 86 is closed, however, there is no escape of pressure air to line 79 when the piston, during its upward movement, over-runs port 65 and the piston continues to rise until it uncovers port 87 when air passing through valve 89, and port 77 forces the valve 67 down to thereby vent the space below the piston 62 and allow it to descend. When the piston uncovers port 87 the pressure in line 79 closes valve 89 and the piston continues to descend until it over-runs port 65 and the space above valve 67 is vented through valve 84. The valve 67 is then reversed by the spring 76 and the cycle recommences, the piston reciprocating between a point just below port 65 to a point 90 just above port 87. In a further modification, Fig. 8 (not shown), the valve 89 may be by-passed by a line arranged in parallel with the line 88 and provided with a stop valve which when open, and with valve 86 closed, causes the piston to reciprocate through a relatively short stroke above and below port 87. In a still further modification variation of stroke is afforded by providing two ports in the cylinder between the ports 65 and 87, each such intermediate ports being connected to line 79 by lines incorporating a stop-valve and a check-valve.