Diaphragm gauges

Eveiy effort should be made to eliminate direct (Bourdon-type) pressure gauges. Diaphragm pressure gauges constructed of appropriate corrosion-resistant materials are preferred. Flow limiters should be used to limit flow in case of loss of integrity... 

Electrolysis of fused sodium hydroxide has heen achieved successfully with a Castner cell. The Castner cell was used in commercial production prior to introduction of Downs cell. The cell is operated at a bath temperature 320 10°C, at 9.0 0.5 amp current and a voltage of 4.3 to 5.0 V. The cathode current density is about 10.9 kA/m2. The cell consists of a copper cathode and a nickel anode and a cylindrical iron-gauge diaphragm placed between the electrodes. The cell reactions are as follows ... 

Bourdon vacuum gauge Diaphragm vacuum gauge... 

Methods of measuring underwater shock waves by crusher gauges, diaphragm gauges piezoelectric gauges are thoroughly described by Cole (Ref 3) in Chapter 7. Cook (Ref 7) describes the use of a 16- to 64-frame/sec camera to measure the free surface vel produced by a shock wave at the surface, and the determination of the underwater pressure-distance curve for TNT... 

Fig. 11. Diaphragm-box systems, open and closed types, used where pressure gauges cannot be located at the minimum tank level.

Pressure. Most pressure measurements are based on the concept of translating the process pressure into a physical movement of a diaphragm, bellows, or a Bourdon element. For electronic transmission, these basic elements are coupled with an electronic device for transforming a physical movement associated with the element into an electronic signal proportional to the process pressure, eg, a strain gauge or a linear differential variable transformer (LDVT). 

Gauges. Because there is no way to measure and/or distinguish molecular vacuum environment except in terms of its use, readings related to gas-phase concentration ate provided by diaphragm, McCleod, thermocouple, Pitani gauges, and hot and cold cathode ionization gauges (manometers). 

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. 

A diaphragm gauge depends for its indication on the deflection of a diaphragm, usually metalhc, when subjected to a difference of pressure between the two faces. These gauges are available for the same... 

Bourdon and diaphragm gauges that show both pressure and vacuum indications on the same dial are called compound gauges. 

Conditions of Use Bourdon tubes shoula not be exposed to temperatures over about 65°C (about 150°F) unless the tubes are specifically designed for such operation. When the pressure of a hotter fluid is to be measured, some type of hquid seal should be used to keep the hot fluid from the tube. In using either a Bourdon or a diaphragm gauge to measure gas pressure, if the gauge is below the... 

For measuring pressures of corrosive fluids, slurries, and similar process fluids which may foul Bourdon tubes, a cfiemical gauge, consisting of a Bourdon gauge equipped with an appropriate flexible diaphragm to seal off the process fluid, may be used. The combined volume of the tube and the connection between the diaphragm and the tube is filled with an inert liquid. These gauges are availabTe commercially. 

Rgure 8-31. Multiple diaphragm flexible element coupling with a strain gauge type torque meter. Courted ofZum Industrie Inc., Mechanical Drives DMsforii... 

C, diaphragm pressure gauge, measured range 30-70°C, Ambrose et al. 1976)... 

---