| 摘要 |
1,207,866. Pressure indicator for filter. PUROLATOR Inc. 11 Jan, 1968, No. 1553/68. Heading BID. [Also in Division GIL] In a differential fluid pressure indicator, such as for indicating when a filter needs replacing, the upstream side of the fluid flow to the filter is connected to a high pressure port and the downstream side to a low pressure port 3 and the arrangement is such that any predetermined pressure increase due to increased resistance to fluid flow by the filter causes a piston 5 to move against a spring 9 to cause a magnet 10 carried by the piston 5 to repulse a magnet 11, on the other side of a fluid tight wall 8, to move a button 7 rapidly to a projected signalling position in which the button 7 is held by a cap 19 of magnetic material A disc 22 of magnetic material snaps the button 7 to its non signaling position when the button 7 is depressed. Bimetallic strips may be provided to prevent movement of the button 7 when the fluid is cold. |
