SST and QST Split Sheath Insertion Heaters
|The SST and QST Split Sheath Insertion Heaters are designed especially for platen, die or mold heating applications where the holes are poorly drilled or worn through age. Independent expansion of each section of the SST and QST when energized, creates intimate contact with the wall of the hole. SST Insertion Heaters have a single split along the length. The two sections expand in opposite directions. Conductive heat transfer is excellent. The QST, or Quad, has additional sections that expand in four directions. Surface contact is superior to any available insertion heater. The simple internal design of the SST and QST generates a uniform linear temperature profile. Perhaps the most outstanding feature is how easy the SST and QST Split Sheath Insertion Heaters are removed from the hole for replacement or other servicing requirements. As the temperature cools, the sections contract, allowing the SST and QST to slip from the hole without difficulty. In platens and presses utilizing long, conventional cartridge heaters, Ogden’s split sheath design can reduce down-time and maintenance costs. Where repair or redrilling of the hole is not practical, the SST and QST offer outstanding performance.|
|Split Sheath design
Improved conductive heat transfer
Easily inserted and removed from long holes
Incoloy Sheath for long life at extreme temperatures
Compacted to maximum density for excellent element to sheath heat transfer and dielectric strength
|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).
|TerminationsFig. 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 BigChief.
|TerminationsFig. AS Stainless Steel Armor Cable Lead Protection
Armor cable is the best protection against abrasion or other damage to lead wires. A straight transition adapter with 12″ stainless steel armor cable and 14″ lead wires is standard. Specify longer length.Fig. DS Right Angle Stainless Steel Armor Cable Lead Protection
Figure DS shows an SST Insertion Heater with right angle stainless steel armor cable protected leads. Figure DS is for use where spacing is limited and for wiring convenience. 12″ cable and 14″ overall length leads are standard. Specify longer length.Fig. FS Flexible Stainless Steel Braided Leads
Figure FS flexible stainless steel braid protects leads from sharp edges. The braided sleeving is virtually as flexible as non-protected leads. 12″ stainles steel braid with 14″ leads are standard. Specify longer length.Fig. GS Right Angle Flexible Stainless Steel Braided Leads
Figure GS right angle flexible stainless steel braid protects lead wires from abrasion and are full length flexible at a right angle orientation for installations with limited spacing. 12″ stainless steel braid with 14″ leads are standard. Specify longer length.
* QST (QUAD) N/A in 3/8″ Diameter
|TOLERANCES AND LIMITATIONS|
|Nominal Sheath Diamter||3/8″||1/2″||5/8″||11/16″||3/4″||1″|
|Actual Sheath Diameter (±.003″)||.370″||.495″||.620″||.682″||.745″||.995″|
|Minimum Sheath Length||5″||5″||5″||5″||5″||5″|
|Maximum Sheath Length – SST||72″||120″||120″||120″||120″||120″|
|Maximum Sheath Length – QST||N/A||60″||60″||60″||60″||N/A|
|Minimum Ohms/inch of EHL||SST||.278||.308||.296||.296||.350||.350|
|Maximum Ohms/inch of EHL||SST||11||21||21||21||26||26|
|Wattage||+5% – 10%|
|Sheath Length||+3% up to 20″; ±2% over 20″|
Available Metric Diameters:
10mm, 12mm, 12.5mm, 14.5mm, 16mm, 18mm, 20mmFit = maximum inside diameter of hole minus minimum O.D. of sheath
Example: a 3/8″ heater in a .375″ ±.001″ reamed hole would have a .007 fit .376 – .367 = .009Check the required temperature against the watt density and fit indicated on the graph above.