Pressure gauge, electronic

The indicator element measures the signal from the weighing element, and converts it into a readable form. It may be any of several different types, eg, the graduated beam of Figure 3, a Bourdon tube pressure gauge, or a numeric display device. Today (ca 1997), with the increase in automation, the indicator element may not display the weight but may instead transmit it electronically to a controller. 

Aneroid gauge, electronic An aneroid gauge with the advantage of being able to integrate the velocity pressure directly into velocity. 

Figure 2.16 Electronic pressure gauge to follow/control the pressure in sapphire NMR tubes. The small dead volume allows the pressure in the tube to be measured precisely and also allows the pressure variation to be monitored with time.

A schematic diagram, Figure 6, shows a typical underwater test configuration and oscilloscope record used to determine shock wave impulse. The pressure vs. time is displayed both at fast and slow scope speeds and the impulse vs. time at the faster scope speed. The impulse vs. time is electronically integrated from the pressure vs. time signal from the pressure gauge. 

Figure 16-3. Principle of a tensiometric set-up for monitoring in-situ solid state reactions [J. Janek (1992)]. 1) Gas pressure gauge, 2) gas supply, 3) vacuum pump, 4) registration electronics, 5) furnace.

Electronic manometers provide a convenient method of pressure measurement in a tensimeter, and the general arrangement may be very simple (Fig. 9.3). The one problem which must be anticipated is long-term zero pressure drift, which can be encountered with an electronic pressure gauge. Drift is minimized by maintaining a constant temperature on the pressure transducer and by avoiding mechanical vibration at the transducer. 

It consists of millions of embedded electronic measuring devices thermostats, pressure gauges, pollution detectors, cameras, microphones, glucose sensors, EKGs, electroencephalographs. These will probe and monitor cities and endangered species, the atmosphere, our ships, highways and fleets of trucks, our conversations, our bodies - even our dreams, (citation from [41])... 

Spring balances are still used in certain research investigations when adsorption equilibration is very slow, e.g. for the study of hysteresis phenomena. For this purpose, it is advisable to replace the mercury manometer by a modem pressure gauge. However, in recent years spring balances have been largely superseded by electronic microbalances. The essential features of an electronic, null adsorption microbalance are indicated in Figure 3.11. 

The continuous enzyme membrane reactor (CMR). (1) Temperature-controlled water-bath (2) Feed tanig (3) Stirrer motor for feed tank (4) Feed pump (5) Feed inlet line to the reaction vessel (6) Reaction vessel (7) Magnetic stirring table (8) Prefilter (9) Recycle pum (10) Flowmeter (11) Membrane inlet pressure gauge (12) Hollow fiber membrane cartridge (13) Membrane outlet pressure gaug (1 Pressure adjusbneut valve (15) Retentate recycle line (16) Air bath environment (17) Pemieate (product) line (18) Permeate collection vessel (19) Electronic balance... 

Figure 5.2.1. Simplified diagram of a Py-GC system (not to scale). The pyrolyser is schematized as a heated filament type. A piece of a deactivated fused silica line is passed through the injection port of the GC and goes directly into the pyrolyser. This piece of fused silica is connected to the column, which is put in the GC oven. The pneumatic system consists of (1) a mass flow controller, (2) an electronic flow sensor, (3) a solenoid valve, (4) a backpressure regulator, (5) a pressure gauge, and (6) septum purge controller. The connection (7) is closed when working in Py-GC mode, and connection (8) is open. (Connection (7) is open when the system works as a GC only.) Connection (9) is closed and connection (10) is open when the GC works in splitless mode (purge off). Connection (10) is closed and connection (9) is open when the GC works in split mode (purge on). No details on the GC oven or on the detector are given.

Simple pressure gauges and or electronic pressure gauges can be included in the system for monitoring as well as solenoid switches with transmitters to turn gas flow on and off, change flow rates, and/or just simply read pressure. If you use any electronic switch or monitor it must... 

Electronic pressure gauge. (From Baukal, C. E., Industrial Combustion Pollution and Control, New York Marcel Dekker, 2004.)... 

Examples include insulin syringes, blood pressure gauges, most diagnostic reagents, adult incontinent products, electric heating pads, clinical electronic thermometers, powered wheel chairs, infusion pumps, and surgical drapes. 

The problem of determining the pressure of neutral gas in the source, especially at relatively low pressures, was for some time considerably more difficult. Before satisfactory low-pressure gauges were available, the source pressure was determined as follows The repeller was biased negatively to the source in order to collect all of the ions formed. Argon or neon, of known ionization cross section, was admitted to the source under conditions of molecular flow through the leak and the total positive ion current collected on the repeller was recorded as a function of reservoir pressure while maintaining a constant, known current of electrons. Under these conditions. 

Figure 5.11 I Schematic diagram of an ionization gauge. Electrons emitted from the hot filament collide with gas molecules and knock an electron free. The resulting cations are collected at the center of the gauge, and the current they produce is a measure of the gas pressure.

The hydrostatic pressure results from the weights of the continuous and dispersed phase and can, thus, serve as a measure for the particle mass or volume concentration. In the context of analytical sedimentation, it was already utilised by Ostwald and Hahn (1922), who quantified the rate of sedimentation of flocculated suspensions by means of a hydrostatic pressure gauge. More recent papers report on the manometric determination of the hydrostatic pressure in analytical cuvettes centrifuges with electronic pressure transmitters (Bickert 1997 Beiser 2005). In contrast to the detection systems portrayed above, these manometer centrifuges do not measure a local particle concentration, but the total mass of all particles that are suspended above the point of measurement. The cumulative function of the volume weighted size distribution (gsfxstokes)) can be, thus, computed liom the time derivative of the hydrostatic pressure. In that regard, the manometric detection shows similarity to the sedimentation balance. 

Pressure can be measured by means of manometers which show the pressure in terms of the different levels of a liquid in a U-tube, by mechanical pressure gauges which record the differential effect of pressure forces on the inside and outside surfaces of a coiled tube, and electronic devices which measure the change of electrical characteristic of an element with pressure. 

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