Electric operator

Transesterification. There has been renewed interest in the transesterification process for preparation of polycarbonate because of the desire to transition technology to environmentally friendly processes. The transesterification process utilizes no solvent during polymerization, producing neat polymer direcdy and thus chlorinated solvents may be entirely eliminated. General Electric operates a polycarbonate plant in Chiba, Japan which produces BPA polycarbonate via this melt process. 

Magnetic motor starters are similar in function to manual starters except that thev are solenoid-operated, Thev are available up to 3730 kW (5()()0 hp). One of the main advantages is the convenience of electrical operation. Start-stop push buttons can be located anywhere, lien automatic or remote operation is needed, magnetic starters are essential. 

Electrical interlocking scheme when the interrupters are also electrically operated... 

Small interrupters and MCCBs particularly may be electrically operated through a solenoid valve. 

Figure 13.45 Control scheme for two electrically operated sources of supplies...

Figure 13.47 Control scheme for three electrically operated sources of supplies and two bus couplers...

Control of the compressor is achieved by engaging the required number of cylinders. In. say. a 16-cylinder compressor if we engage only four cylinders, the compressor will run at 25 7r capacity, and if w c engage eight cylinders, the compressor will run at. 5()C< capacity. Electrically operated solenoid valves are provided for capacity control. Energy can be conserved by using static controls, as discussed in Section 6.15. 

These may be used to feed the solenoid or the motor of an interrupting device (such as an electrically operated breaker), indicating lights and circuits, auxiliary contactors or relays, electrical or electronic timers, hooters or buzzers, and all such auxiliary components and devices mounted on a controlgear or a switchgear assembly requiring a specified control voltage. 

Fig. 10-5 Protection measure by separation of electrical operational equipment that is connected to the cathodically protected object via the housing, with an FI protection circuit leakage current circuit breaker (see Ref. 14) Tj and isolating transformers (see Ref. 15).

Fire and smoke damper. A device used to isolate one area of a building from fire or smoke in another, or one part of a duct run from fire or smoke in another. The device is mechanically or electrically operated in case of fire. 

Siemens constructed the first electric railway shown at the Berlin Trade Fair of 1879 and the first electrically-operated lift m 1880, and the first electric trams began operating in Berlin in 1881. Siemens received many honors for his work an 1860 hon-oraiy doctorate from the University of Berlin, an 1873 membership m the Royal Academy of Science, and an 1888 knighthood from Emperor Friedrich III. Siemens died m Berlin, Charlotteiiburg, on December 6, 1892. 

The performance of the unit involves the gas characteristics, analysis, velocity, flow rate, dust or liquid particle size and analysis, resistixdty and required final particle efficiency of removal. Some particle materials of high electrical resistivity prevent proper electrical operation. 

Assessments should be made for electrically operated process equipment that may require an essential power supply in the event of a main failure. 

The number and quality of the safety shut-off valves required is specified in the relevant Standards and Codes of Practice. These are usually electrically operated valves conforming to class 1 or class 2 as defined in BS 5963, Specification for electrically-operated automatic gas shutoff valves (1981). This specifies forward pressures and reverse pressures that the valve must withstand in the closed position together with closing times. 

Valves other than electrically operated (e.g. pneumatically operated ball valves) are equally acceptable if the pressure and closing time requirements of BS 5963 are met. 

Figure 23.12 Diagram of electrically operated automatic steam stop valve (with permission of Hopkinsons Valves Ltd, Huddersfield, UK)...

Many operations involving solutions of reagents require the thorough mixing of two or more reactants, and apparatus suitable for this purpose ranges from a simple glass stirring rod to electrically operated stirrers. 

The demand for electrically operated tools or devices that can be handled independently of stationary power sources led to a variety of different battery systems which are chosen depending on the field of application. In the case of rare usage, e.g., for household electric torches or for long-term applications with low current consumption, such as watches or heart pacemakers, primary cells (zinc-carbon, alkaline-manganese or lithium-iodide cells) are chosen. For many applications such as starter batteries in cars, only rechargeable battery systems, e.g., lead accumulators, are reasonable with regard to costs and the environment. 

The manifold also receives and mixes solvents from each of the programmed valves. The valves are electrically operated and programmed to open and close for different periods of time by adjusting the frequency and wave form of the supply. Thus, a predetermined amount of each solvent is allowed to flow into the manifold. The valves can be driven by oscillators contained in a separate electronic programmer or if the chromatograph is computer controlled, the controlling waveform and frequency can be provided directly from the computer. 

Masks are available with battery-powered filter packs which supply filtered air to a facepiece from a haversack filter unit. Another type comprises a protective helmet incorporating an electrically operated fan and filter unit complete with face vizor and provision for ear muffs. 

Where floor drainage channels are necessary they should be open if possible, shallow and easy to clean. Connections to drains should be outside areas where sensitive products are being manufactured and, where possible, drains should be avoided in areas where aseptic operations are being carried out. If this cannot be avoided, they must be fitted with effective traps, preferably with electrically operated heat-sterilizing devices. 

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