PFA heaters are designed specifically for use as direct electric heaters in plants and tanks where space is at a premium and high heating capacities and excellent resistance to aggressive process liquids are required. The very good chemical resistance of the heating cable is achieved by the use of a special sheath made of FEP or PFA. The surface power density is only 1 W/cm2.
The PFA sheath should be selected for particularly critical operating conditions in extremely aggressive process liquids (such as mixed-acid chrome electrolyte) and for very high liquid temperatures (max. 100°C). The wide range of different shapes and designs provides simple solutions to even difficult installa- tion problems. Small dimensions, combined with relatively high heating powers, permit space-saving installation. The use of high-quality materials guarantees a long operat-ing lifetime with optimum reliability and thus ensures problemfree op-eration of the plant.
Construction
These heaters consist of a metal heating wire in a FEP / PFA sheath, wound on a flexible PTFE or PVDF support frame. The mounting ele- ments and the spacers which prevent direct contact between the windings of the heating cable and between the windings and the tank, are also made of PTFE or PVDF. The mechanical strength can be improved by mount- ing the heater in a steel frame with PTFE / PVDF sheath (Model A) or in a robust PP / PVDF frame (Models E / F).
A protective plate made of PTFE or PVDF (Models Q / R) protects the heater against mechanical damage.
The unheated connection cable leaving the heater is also sheathed in as far as the connection sleeve and is secured in a PP expandable braided sleeving. This part of the heater can be immersed in the process liquid and carries markings for the minimum and maximum im- mersion depth. Even in applications with extreme level variations, the liquid level must remain within this range! From the PTFE connection sleeve (degree of protection IP 64 to EN 60529), a PTFE connection cable leads to the switchgear cabinet.
The connection sleeve may not be immersed in the liquid, nor may it be directly exposed to vapours.
Specifications
| Heater | Patented PreciseHeater® Coil |
|---|---|
| Wetted Surfaces | PTFE/PFA |
| Sizes | 1.0kW to 30kW (Dependent on Customer Voltage) |
| Voltages | 110VAC to 600VAC 1 or 3ph (Dependent on Wattage) |
| Temperature | 200°C (392°F) |
| Temperature Accuracy | ±0.1°C (Contingent on Customer's Facilitation) |
| Efficiency | >99 % |
| MTBF | 10.29 years |
Dimensions
| Model | kW | Height | Benefits |
|---|---|---|---|
| Grid | 1-6 kW* | 3/4 in | Low Profile Design |
| Frame | 1-30 kW | 1-1/2 in | Low Profile Design for Higher kW's |
| Fence | 1-10 kW | Variable | Heater on side of tank leaving center of tank open |
