What is a Strip Heater?

A strip heater is a device which is mounted on a surface and used to heat the surface or air (gasses).

Application of Omegalux® Strip Heaters

OMEGALUX® strip heaters are used principally for convection-type air heating and clamp-on installations. When selecting strip heaters for either, two important factors must be considered:

• The proper sheath material for resisting any rusting and oxidising inherent in the process or environment and for withstanding the sheath temperature required. Standard sheath materials are rust resisting iron, chrome steel and Incoloy (NS Series only). Stainless steel and Monel sheaths are available at an additional charge. Maximum work and sheath temperatures are below.
• The watt density of the element, or watts per square inch of heated area. This should be low for heating asphalt, molasses and other thick substances with low heat transferability; it can be higher for heating air, metals and other heat conducting materials. (See curves for determining allowable watt densities).

Selection of Strip Heaters for Air Heating

Select maximum desired operating air temperature on (D) Choose either chrome steel sheath or rust-resisting iron sheath (points E) on basis of operating conditions Draw straight line through points (D) and (E) to reading on (F) giving maximum allowable watts per square inch Select desired length heater with equivalent watt density or less

Selection of Strip Heaters for Clamp-On Applications

Select maximum desired work temperature on (A) Choose either chrome steel sheath or rust-resisting iron sheath (points B) on basis of operating conditions Draw straight line through points (A) and (B) to reading on (C) giving maximum allowable watts per square inch Select desired length heater with equivalent watt density or less

Selection of Watt Density for Finned Strips

Select a maximum desired air temperature on A Choose sheath material to suit operating conditions Select minimum anticipated air velocity on B. Note: Natural circulation is equal to one foot per second Draw straight line through the points selected on A and B-read C for allowable watt density Select required length heater with equivalent watt density or less

When high operating temperatures are needed, watt density must be limited in order not to exceed the maximum sheath temperature. Watt density is given in the "How To Order" table for each strip heater. In general, a viscous material with low thermal conductivity requires a low watt density. High watt densities can be used with thinner liquids and with materials of high thermal conductivity. Premature loss of the element due to excessive temperature may result if the material's heat-take-away ability is low. Also, the material may be charred, carbonised or its chemical makeup altered by overheating.

Standard Strip Heaters

The HCS Series stainless steel strip heaters provide clean, dependable heat with sheath temperatures up to 649°C (1200°F) and watt densities up to 40 W per square inch. Because of the seamless stainless steel sheath, these ceramic-insulated strip heaters are dimensionally stable in milled slots.

Finned Strip Heaters

High-quality, coiled nickel-chrome resistor wire is uniformly spaced over the width and length of the finned strip element, then embedded in high-grade refractory material which both insulates the wire and transfers heat rapidly. The refractory is then compressed to rock hardness and maximum density under tremendous hydraulic pressure to improve heat transfer from coil to sheath. Elements are oven baked at high temperatures to semi-vitrify and mature the refractory. Sheath material is either rust-resisting iron or chrome steel. Fins of aluminised steel are provided to improve that transfer to the air. Elements are individually replaceable.

Seamless Incoloy Sheath Strip Heaters

Strip-heater advantages for higher temperature applications are offered by NS series. The heater design, materials and construction give long life for given power densities. The Incoloy sheath encloses nickel chromium resistance wire embedded in a densely compacted refractory material selected for dielectric insulation value and good heat conduction to the sheath. The small cross-section is often an advantage where space is a factor.

Wide Strip Heaters

The OMEGALUX® WS series strip heater features 2 terminals placed at a right angle on one end. A standard width of 2 1/2" makes them ideal for most strip heater applications.

Ring Strip Heaters

The ring strip heaters are easy to install. The flat circular shape are ideal products for heating tank bottoms, lead melting pots, dies, platens, hotplates, incubators and many other applications.