Transducers, pressure

The experimental activity was carried out on a cylindrical pressure vessel whose capacity is 50 litres and made from steel 3 mm thick. Fig. 2 shows the layout of the pressure vessel considered. The pressure vessel was connected to an oil hydraulics apparatus providing a cyclical pressure change of arbitrary amplitude and frequency (fig.3). Furthermore the vessel was equipped with a pressure transducer and some rosetta strain gauges to measure the stresses on the shell and heads. A layout of the rosetta strain gauges locations is shown in fig.4. 

Standard commercial iastmmentation and control devices are used ia fluorine systems. Pressure is measured usiag Bourdon-type gauges or pressure transducers. Stainless steel or Monel constmction is recommended for parts ia contact with fluoriae. Standard thermocouples are used for all fluorine temperature-measuriag equipment, such as the stainless-steel shielded type, iaserted through a threaded compression fitting welded iato the line. For high temperature service, nickel-shielded thermocouples should be used. 

Linear-Variable-Differential-Transformer and Reluctive Pressure Transducers. In ahnear-vatiable-differential-transformer (LVDT) pressure transducer, the pressure to be measured is fed to a Bourdon tube or diaphragm. The motion of this element is transferred to the... 

Fig. 6. Impact of field bus on wiring costs, where A/D and D/A correspond to analogue-to-digital and digital-to-analogue converters, respectively LCU = local control unit and I/P = current-to-pressure transducer, (a) DCS without remote terminal rooms (b) DCS with remote terminal rooms and...

G = current-to-pressure transducer(I/P) H = actuator and I = final control element. Some devices combine A, B, and C, and (--) represents the line... 

Another type of rotational viscometer is the hehcal-screw rheometer (176). This iastmment is basically a screw-type metering pump that does not pump. The measure of force is the pressure difference resulting from the rotational motion. It is possible to use a bank of pressure transducers of different sensitivities to measure viscosity over a wide range. The iastmment can be used for high temperature rheometry and to foUow polymerkation, shear and heat degradation, and other developments. 

Strain-gauge pressure transducers are manufactured in many forms for measuring gauge, absolute, and differential pressures and vacuum. Full-scale ranges from 25.4 mm of water to 10,134 MPa are available. Strain gauges bonded direc tly to a diaphragm pressure-sensitive element usually have an extremely fast response time and are suitable for high-frequency dynamic-pressure measurements. 

Piezoelectric Transducers Certain ciystals produce a potential difference between their surfaces when stressed in appropriate directions. Piezoelectric pressure transducers generate a potential difference proportional to a pressure-generated stress. Because of the extremely high electrical impedance of piezoelectric crystals at low frequency, these transducers are usually not suitable for measurement of static process pressures. 

The use of dynamic pressure transducer in the combustor section, especially in the Low NOx Combustors ensures that each combustor can is burning evenly. This is achieved by controlling the flow in each combustor can till the spectrums obtained from each combustor can match. This technique has been used and found to be very effective and ensures smooth operation of the turbine. 

The use of dynamic pressure transducers gives early warning of problems in the compressor. The very high pressure in most of the advanced gas turbines cause these compressors to have a very narrow operating range between surge and choke. Thus, these units are very susceptible to dirt and... 

Combustor-shell pressure transducer line drain solenoid valve energized. 

Implementation of advanced performance degradation models, necessitate the inclusion of advanced instrumentation and sensors such as pyrometers for monitoring hot section components, dynamic pressure transducers for detection of surge and other flow instabilities such as combustion especially in the new dry low NO combustors. To fully round out a condition monitoring system the use of expert systems in determining fault and life cycle of various components is a necessity. 

At each of the measurement locations, pressure probes may be attached to a harness, and these probes will direct the air flow to external pressure transducers for measurement while serving as a sheath for the appropriate thermocouple at that location (each thermocouple will be seated inside a pressure probe). 

The measured head h it) is obtained from the pressure transducer... 

SAMPLE PRESSURE TRANSDUCER. VESSEL PRESSURE TRANSDUCER CONNECTIONS FOR INJECTION... 

Secondly, the pressure drop, P, in the above expression is the pressure drop due to shear flow along the die. If a pressure transducer is used to record the... 

The second, mechanical and electrical manometers, require more frequent calibration. Changes in the elastic properties of the pressure transducer, wearing in mechanical parts, and electronic circuitry drift influence the properties of the instruments, giving rise to repeated calibration. 

P. G. Dargie, S. T. Hughes. A thick-film capacitive differential pressure transducer. Measurement Science and Technology, 5, 1994, pp. 1216-1220. 

Elsworth et al. (1983) report experiments performed in an open-topped channel 52 m long x 5 m high whose width was variable from 1 to 3 m. Experiments were performed with propane, both premixed as vapor and after a realistic spill of liquid within the channel. In some of the premixed combustion tests, baffles 1-2 m high were inserted into the bottom of the channel. Ignition of the propane-air mixtures revealed typical flame speeds of 4 m/s for the spill tests, and maximum flame speeds of 12.3 m/s in the premixed combustion tests. Pressure transducers recorded strong oscillations, but no quasi-static ovetpressure. 

Most high-performance liquid chromatography (HPLC) pumps can be used in HOPC. The back pressure rating should be at least several thousand pounds per square inch (a few hundred kg/cm ). A type of pump that does not allow bypassing the pressure transducer or a pulse damper, if it is installed, must not be used. The dead volume should be as small as possible. Pumps with a single plunger are better than those with two plungers. 

Figure 4-250. Surface pressure transducers location for pump noise elimination.

Signal pressure transducer (SPT) at mud pump records wave phase at stad. 

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