Reactors high-frequency

Thermal CVD requires high temperature, generally from 800 to 2000°C, which can be generated by resistance heating, high-frequency induction, radiant heating, hot plate heating, or any combination of these. Thermal CVD can be divided into two basic systems known as hot-wall reactor and cold-wall reactor (these can be either horizontal or vertical). 

The simulated FBAC consists of an acrylic main reactor (0.5m-H x 0.5m-W x l.Om-L), an air distributor system, particles feeding system including a feed hopper, a discharging sampler, a bag filter for capture of the elutriated fine particles and, pressure and flow rate measurement systems (Fig. 1). The air distributor system has ten air headers. An individual air header is connected with 5 air nozzles and can regulate the airflow rate. The opening ratio of the distributor is 2.1% and each nozzle has four holes for uniform air supply. To measure the pressure fluctuation at an individual air header, high frequency pressure transmitters were mounted at the approach and the exit headers of the FBAC. 

Del Campo FJ, Coles BA, Marken F et al (1999) High-frequency sonoelectrochemical process mass transport, thermal and surface effects induced by cavitation in a 500 kHz reactor. Ultrason Sonochem 6 189-197... 

Figure 3.7 High-frequency part reactor temperature = 350 K.

With respect to the re-deposition of a coating on the first wall, the obvious advantage is the compatibility with Tokamak operation since it requires a minimum of auxiliary equipment and modification, particularly if a continuous, high frequency discharge is used. The power requirements for such an approach appear to be acceptable134. An rf heating system, if incorporated into the reactor design (e. g. 

Current commercial plasma-enhanced CVD reactors operate with only two physical concepts. In one case, we have the inductively-excited discharge in a tube, which is used for plasma ashing of resist. The other is the parallel plate arrangement using high-frequency RF power to create a low-pressure glow discharge, where the wafers to be coated sit on one of the electrodes. 

Finally, we will consider PECVD silicon oxynitrides, and their unique characteristics. When oxygen is added to a PECVD nitride film, there are indications that it may improve its crack resistance as a final passivation layer.13 Also, there may be advantages in terms of its electrical characteristics as an interlayer dielectric. Therefore, the nature of films grown when N20 is added to a SiH4, NH3 and He gas mixture in a high frequency (13.56 MHz), cold-wall, parallel-plate reactor have been studied. 

The vibrating fluidized bed is useful for processing particles that are difficult to fluidize because of stickiness, wide polydispersity, agglomerating tendency, large size, and extreme friability. High-frequency (10-100 Hz) and small-amplitude (1-10 mm) vibrations imparted to relatively shallow beds of particulate solids have been found to facilitate fluidization of difficult-to-fluidize solids. The use of such a fluidized bed for the chemical reactor has been evaluated by Mazumdar (1984). The detailed transport characteristics of a vibrating fluidized bed were recently outlined by Endesz et al. (1989). 

The measurement of pg requires a pressure transducer system that is not influenced by the electric power used for the plasma polymerization, particularly when a high-frequency radio frequeny power is employed. Some pressure transducers that give pressure readouts independent of the nature of a gas are ideally suited for plasma polymerization. Some electronic gauges the readout of which depends on the nature of the gas (e.g., thermal conductivity) do not provide accurate readings of Pg because in most cases the composition the gas mixture in the LCVD reactor is unknown and there is no way to calibrate the meter for an unknown gas mixture. 

The presentation of the result in the frequency domain offers an additional advantage. The reactor behaviour modelled (Comb. Chamber (,i) can be directly compared with the behaviour calculated (Comb. Chamberc t,). The calculated frequency response of the reactor is the ratio of Che measured output and input spectra. This comparison is not possible in the time domain due to the measurement noise at high frequencies. This noise is amplified by the compensation of the measurement dynamics and thus no useful presentation of data is possible in the time domain. 

A screw conveyor takes the comminuted raw material into a coaxial cylindrical chamber. On the left-hand side, this chamber features a reciprocating annular piston actuated hydraulically at a frequency of 120 strokes per minute to form a plug of compressed raw material serving as a pressure lock between the ambient atmosphere and the hydrolysis reactor. Due to its high frequency of operation, this feeder is likened to a machine gun. On the right-hand side, the chamber features a choke applying an adjustable pressure on the plug of raw material, and... 

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