Manifold coil heaters

Tubular manifolds. An example of a tubular manifold is a design in which the flow channel is in a tube. The tube is heated by coil heaters in ceramic insulation and is set in a hole in a plate transferring the external load (see Figure 4.63). The low mass of the tubular manifold and its insulation by air gaps means the plate temperature is relatively low. Because of the very small temperature fluctuations, this manifold is recommended for the injection of plastics that are difficult to process, LCP, PA 66, PBT, PC, PEEK, PET, PSU, PVC with glass fibre, etc. 

The heaters used for external heating of plate manifolds are of the cartridge or tubular resistance type operating on 230 V AC current. Tubular manifolds are heated by 230 V coil heaters or low-voltage 24 V or 5 V, heaters. 

Coil heaters used to heat tubular manifolds are shown in Figure 4.63. 

As shown in Figure 1, an SFA system consists of five basic components sample changer, peristaltic pump, analytical manifold, detector, and data output system. The manifold contains the mixing coils, dial-yzer, heater, and other components through which sample and reagents are pumped and where sample clean-up and reaction takes place. The data output... 

In contrast to other heaters, there is a single coil inside the tube, and the positive and negative wires are located on opposite sides of the heater. This design largely eliminates the possibility of insulation breakdown. The cold ends of the heater, some 50 mm in length, are not heated and should be situated outside the manifold. One operational fault that occurs is that these ends get broken when care is not exercised in servicing. The thermal density of a tubular heater is about 15 W/cm. ... 

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