초록

A control circuit (56) for responding to infrared light from a target region and operating an electric valve (54) in response is disposed at a protected location remote from the target region. It detects the presence of objects by means of light conducted to it by a fiber-optic cable (32).

대표청구항 ▼

[ What is claimed is:] [1.] An automatic flow-control system comprising:A) a conduit, having an inlet and an outlet, for conducting to its outlet fluid received at its inlet;B) an electrically operated valve interposed in the fluid conduit and operable by application of control signals thereto betwe

[ What is claimed is:] [1.] An automatic flow-control system comprising:A) a conduit, having an inlet and an outlet, for conducting to its outlet fluid received at its inlet;B) an electrically operated valve interposed in the fluid conduit and operable by application of control signals thereto between an open state, in which it permits fluid flow from the conduit inlet to the conduit outlet, and a closed state, in which it prevents fluid flow from the conduit inlet to the conduit outlet;C) a variable optical-radiation source for generating optical radiation and shining it into a target region, the optical-radiation source being responsive to control signals applied thereto to vary the intensity of the optical radiation that it generates;D) a sensor circuit for detecting optical radiation reflected by objects in the target region and for applying control signals to the electric valve to control fluid flow therethrough in response to at least one predetemined characteristic of the sensed optical radiation; andE) control circuitry responsive to the sensor circuit for applying control signals to the optical-radiation source to cause it to generate optical radiation whose intensity results in a predetermined level of optical radiation received by the sensor circuit.