Solid-state pressure transducers

Although there are a variety of pressure transducer types available, for most lespiiatory applications the newer solid-state pressure transducers offer the most attractive alternative. Variable-capacitance... 

Solid-state pressure transducer High([Pg.1960]

Pressure measurement force-balance and elastic element systems, and solid state pressure transducers. 

An alternative technique was to use a small volume liquid nitrogen trap installed between the Teflon membrane and the pressure transducer. At the temperature of liquid nitrogen, all of the possible gas components except H2 condense to a liquid or solid state. For the above experiment, a liquid N2 cold trap was installed in the H2 capillary line between the membrane and the transducer. The trap was evacuated, opened to the line, and cooled. The ratio of postcooling to precooling pressure was 0.92. Assuming ideal mixing of the gas species in the membrane, this... 

Lee DW, Cho Y-H (2009) A quaternary microfluidic multiplexer using dynamic control of pressure valves having different thresholds. In Proceedings international conference on solid-state sensors, actuators and microsystems. Transducers 09, Denver, CO, 21-25 June 2009, pp 433 36... 

The volumetric devices basically include a manometer and some calibrated volumes (introduction volume(s) and the solid sample cell). The temperature in every part is controlled. The adsorbate may be introduced continuously (flow method) or as successive doses (static method) from the introduction volume to the cell. Whatever the method, the number of moles adsorbed is obtained by a material balance and subsequent introduction of P-V-T data in a suitable gas-phase equation of state. The crucial variable to be measured is the pressure, from which this method may be called "manometric". The main problems to be considered are the assessment of the quality of the pressure transducer, and the volume calibrations. We will not consider here the devices with varying volumes (3). 

At the start of every measuring day, the measuring channel and the region of the force transducer were each thoroughly cleaned (the material, which was still solid and only slightly warm, was easier to remove than in the hot state). Then the cavity behind the pressure hole was Ailed with HD-PE, because this does not decompose even when exposed to temperature for long... 

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