| 摘要 |
A filter includes a cylindrical filter element which is arranged to normally have fluid passed therethrough. A linear bypass valve opens in response to a predetermined pressure drop through the filter element and operates an indicator when the valve is opened. A spring within the filter element holds the valve closed at other times. A second spring opens the valve when the filter element or the spring or both are omitted, thus causing the indicator to be shifted in the same manner as when the pressure drop across the element is too high. A compressor for the second spring holds it under stress by contact with the element, making the action of the bypass valve and the indicator independent of the second spring when the pressure drop through the element becomes excessive. |
