| 摘要 |
1,142,766. Filter. MARVEL ENG. CO. 21 March, 1967 [21 March, 1966], No. 13287/67. Heading B1D. A filter assembly in which filter flow to and from filter element 12 is shut off by bypass spool valve means 30 when a certain pressure differential is caused by clogging of the filter element 12 comprises a fluid inlet 17, fluid outlet 19, communicating with filter chamber A, valve means 30 mounted for movement from a position (Fig. 4) enabling the said communication into a position (Fig. 3) wherein portions of the valve means close communication of the inlet and outlet passages 17, 19 with the filter chamber A in response to a pressure differential between the passages 17, 19 caused by contamination of filter element 12, the valve means 30 including a portion 61 (Fig. 3) opening direct communication of the inlet and outlet portions when the valve means is in the position of Fig. 3. In operation normal fluid flow (Fig. 4) is via inlet 17, passages 54 and 14, chamber A, filter element 12, passages 11, 57 and outlet 19. When a pressure differential is caused between passages 17, 54 and passages 19, 57 by clogging of the filter element 12, piston 34 and valve portion 41 will be pressed against the action of spring 40 and move to the right allowing fluid in passage 54 to flow through passage 46 and 44a to force the whole valve means 30 to the right to the position shown in Fig. 3. This closes passages 14 and 11 substantially sealing off filter 12 but allows direct flow from inlet 17 via passage 61 to outlet 19. Filter element 12 can now be removed for cleaning after separating housing portion 3 from head 2. On reassembly, normal filtration can be effected by applying finger pressure to rod portion 38 to move the valve means 30 to the left. The movement of valve means 30 and rod portion 38 to the right when the filter element 12 is clogged may actuate electrical switch elements to shut down operation of the filter and actuate visual or audible signals in addition to the signal given by the position of coloured indicia 49, 39 attached to the valve means 30. |
