Thermal gradients exist along the length and around the circumference of standard sheathed cartridge heaters. These temperature differentials can cause increased camber, resulting in the heater's seizing or binding in the holes. Removal is often difficult and damage to the interior walls of the hole can occur. The uniform temperature profile of the SST and QST allow the separate sections to evenly expand and contract. Removal is easy.

Conductive heat transfer by cartridge heaters in oversized holes is restricted to where surface contact exists. Sheath expansion is limited (A).

Expansion of the SST Split Sheath Heaters when energized is significant, improving heat transfer (B). Diameters are nominally .005" undersized for maximum expansion in standard applications with a fit of .005" - .007". Where an inconsistently drilled or worn hole creates larger fit considerations, the SST Split Sheath Heater offers exceptional performance (C).

The QST, or Quad's effect is similar to the SST with the exception that there are four separate sections (D). Conductive heat transfer is superior to any available insertion heater (E).

 
Terminations

Fig. XS Flexible Leads
Figure XS shows both an SST and QST with standard flexible lead wires for temperatures to 850°F/450°C. 12" length is standard. Specify longer length.

Fig. YS Screw Terminals
Figure YS shows an SST and QST with standard 8-32 x 1" welded nickel plated steel studs. Easy terminal connections are made using lugs, leads or bus bar. Stainless steel, and other thread sizes or lengths are available. Consult Ogden.