Electromagnetic valve actuation

Local electromagnetic and pneumatic components, damper, and valve actuators... 

On-board electrical systems Electromagnetic valve control, catalysts preheating, brake actuators, and steering... 

Figure 1 Component description for Automated Bench top EZE Seal Reactor (1) two way shut-off valve, (2) DC actuated electromagnetic valve, (3) pressure transducer, (4) pressure regulator, (5) ballast tank, (6) autoclave, (7) - substrate injection reservoir. 

In 2000, Unger et al. first used an elastic material (PDMS) and standard soft lithography processes to demonstrate a pneumatic pump with a three-membrane-actuator layout controlled by three external electromagnetic valves (EMV)> respectively [1]. Multilayer soft lithography to fabricate the pump and typical microchannel size was... 

Professor M F Fox (De Montfort University, UK). Could the presenter comment on the possibility of removing the valve train and instead using electromagnetically actuated valves Has any consideration been given to lubricated cam-less valve actuators ... 

Solenoid actuators are used on small valves and employ an electromagnet to move the stem which allows the valve to either be fully open or fully closed. 

An additional advantage of the integrated circuit technology is the ability to integrate the various components, such as the transducer, reactor, valve, pump etc., within the electronic system, forming refined flow-analysis systems on silicon wafers. Several approaches, such as electrostatic, electromagnetic, piezoelectric, thermopneumatic and thermoelectric can be employed for force transduction in the microvalves, these are also applicable to micropumps. Based on these approaches, two versions of micropumps have been developed. These are connected in parallel the first pump (dual pump) is activated with periodic two-phase voltage, while the second pump (the buffer pump) is driven by two piezoelectric actuators. Microsensors of two kinds are described below a thermopile based- and a thermistor based microbiosensor. 

Figure 10.2-5 Schematic diagram of a dynamic still. In this figure, 1 is the boiling flask, 2 is a vacuum jacket so there is no heat loss from the equilibrium chamber, 3 is a device that forces the boiling vapor-liquid mixture into the equilibrium cell 4, items 5 are condensers to insure that no vapor is lost, items 6 are injection ports so that composition changes can be made, 7 is a thermometer port for the bath, items 8 and lO are valves used to divert liquid to the sampling vials (9) for analysis and actuated by electromagnets (13), 11 is the thermometer well for the equilibrium chamber, and 12 is a very accurate platinum resistance thermometer to measure the temperature in the equilibrium cell.

Column heads of semi-technical plants are made up of separate condenser and reflux units. The valves are operated mechanically and, more commonly, electro-magnetically. Their operation is similar to that in laboratory column heads (Figs. 306, 247). The valves are controlled automatically by means of electromagnets, electromotors or pneumatic drives (Fig. 248). For the automatic division of liquid, however, the swinging funnel is chiefly used (Fig. 142) which is actuated by an electromagnet placed outside the column wall. With the magnet switched on the distillate is taken off laterally. 

For some applications the simultaneous incorporation of two actuation principles in a hybrid way can be of interest. An example for this is the combined use of electromagnetic and electrostatic forces in a microvalve [311]. The electromagnetic force is applied for generating large displacements in opening or closing the valve, whereas the electrostatic force can keep the valve in its closed position with very little power consumption. Similarly, the... 

The steam generator safety valves are pilot operated by the steam pressure The opening of the safety vaKe can be manually operated from the main control room by means of two electromagnets installed on the pilots These electromagnets are also automatically de-actuated by a high pressure signal Only one impulse line common to the two pilots is going to the safety valve The two safety valves are "safe close position" type, in the event that the impulse line fails, the valve will be kept closed and non-operable... 

A microfabricated valve with a sample loop, actuated by an electromagnet, is used in some portable GC instruments (7). Usually these instruments use a microfabricated thermal conductivity detector and a microbore column. The use of this approach, however, is limited, since the volume of injected vapor can be changed only by changing the volume of the sample loop. 

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