One-Piece Band Construction
One-piece heaters provide the most heated surface area but can only be used where the entire heater can be slipped over the end of the barrel. One-piece heaters have built-in, full-width clamping bars.
Two-Piece Band Construction
Two-piece construction satisfies the need for a heater that can be placed anywhere along the machine barrel and is recommended for larger diameter heaters. The two-piece construction style also provides dual voltage capability as heater halves may be wired together either in series or parallel. Two-piece heaters are rated at full voltage and 1/2 the total wattage for each half.
One-Piece Expandable Band Construction
The expandable construction style allows the heater to be opened up and placed anywhere along the machine barrel, as well as minimizes the unheated area as compared to a two-piece heater.
With two heater circuits in a common case, this heater naturally lends itself to a dual voltage system. Expandable heaters are rated for each circuit at full voltage and one half of the total wattage.
Partial Coverage Band with Built-In Brackets (2 Piece)
Partial coverage band heaters are required when an obstruction on the barrel would interfere with a full coverage band.
The preferred method of construction is the 2-piece Band Heater with Built-In Brackets. The heater is bolted down to the cylinder at the ends and the built-in low thermal expansion strap pulls the heater tightly against the cylinder being heated. The standard center of hole to the edge of heater dimension is 1/4″.
Partial Coverage Band with Separate Strap (1 Piece)
The alternate method of partial coverage construction is the 1-piece Band Heater with a separate 2-piece strap.
The 2-piece strap itself is bolted at the padded ends, allowing the heater to float between the pads as illustrated below. When tightening the strap, it will pull the heater against the cylinder being heated.
The standard center of hole to edge of heater dimension is 1/4″.