Heater clam shell

SWING VALVE 11.CLAM SHELL HEATER 12.OPTICAL PYROMETER... 

Fig. 12.9 Clam shell heater used for the product transfer lines from the DieMate manifold to the front of the board.

A uniform bead is required for the formation of a strong butt weld. The two ends of the plastic tubing are cut back to obtain square ends. The pipe ends are faced together by a device such as the one shown in Fig. 7.16 which allows the application of a measured axial force to the tubes. A heated plate or a clam shell heater can be used to heat the ends of the tubes. An important step is to thoroughly clean and wipe the ends of the tubes with acetone or another solvent. 

When using certain gases, it is desirable to maintain them at a set temperature for reasons related to the process and for safety. To do this, there are a number of different types of chillers and heaters. Circulating temperature controllers, use a temperature controlled liquid that is circulated through clam shell t)q)e jackets or coils placed around the cylinder. This type of system can have the actual control unit in a remote location and can easily be used in areas classified as hazardous. Another t5q)e controls the temperature of the air that is circulated through the cabinet. The air either transfers to or absorbs heat from the cylinder. Also available to heat cylinders are electrical resistance t5q)e devices. Some of these electrical devices cannot be installed into areas classified as hazardous. 

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