| 摘要 |
<p>Method and apparatus for detecting and obtaining information about (particularly locating) an event. i.e. a change in a variable, for example an increase in the concentration of a fluid as a result of a leak, a change in the physical position of a movable member such as a valve, a change in temperature, or a change in pressure. In a preferred embodiment, three conductors follow an elongate path. One of them (called the locating member (11)) comprises a plurality of spaced-apart resistors (111) separated by low resistance intermediate components (112), so that the locating member has known impedance characteristics along its length. The second conductor (12) is connected to one end of the locating member, but is otherwise insulated from the locating member. When the event occurs, connection is made between the locating member (11) and the second conductor (12) at one or more of a plurality of available connection points, each of which lies between a pair of resistors. With the aid of the third conductor (16), a current of known size is passed through, and the voltage drop is measured between, the connection point and one end of the locating member. The location of the event can then be calculated.</p> |
