| 摘要 |
A method and device for determining the end point for drying in a stream of flowing fluid which method utilizes a reduction in pressure to effect a bypass of fluid flow through a humidity sensor with return of the sample to the main fluid stream. The method is accomplished by placing a first conduit member with the orifice in a nonconfronting manner with respect to the flow and a second conduit member also in the main channel and spaced from the first conduit. A pressure differential is effected between the orifices so as to effect flow through the first orifice to the sensing device and out through the second orifice. In a preferred manner, a pressure differential is effected by utilizing a larger orifice for the second conduit and positioning both orifices opposite the stream flow. A preferred apparatus for effecting the method utilizes a tubular or pipe member for the first conduit which has a curved portion to present an orifice opposite the flow of fluid. A second conduit similar in shape to the first conduit but larger in diameter, is also curved and positioned with an opening facing downstream of the fluid flow and spaced from the first orifice. The opposing ends of the tubular members are connected to a sensing device such as a humidity sensor which preferably is connected to a signal processor which can be utilized to operate a switch or other control equipment such as regulating a drying oven.
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