SL Blocktherm

SL Blocktherm is a self-limiting conduction block, which is designed for attachment directly to the manifold, measuring equipment, control valve and similar devices installed in potentially explosive atmospheres. The block heats the device by conduction.

1. Use

The self-limiting conductive heating block is designed to be mounted directly on a valve assembly, a measuring device, a control valve, and similar devices installed in a potentially explosive atmosphere. The block heats the device by conduction. It is the easiest, safest and most economical way for frost protection or temperature maintenance.

2. Advantages

• Energy savings
• Self-limiting
• No fusable link
• No limiter
• Requires little space
• Adjusts automatically to the voltage

3. Description

SL Blocktherm is a metallic heating block. PTC the cartridge radiates the heat that is transferred by the heating body directly to the connected device.
Explosion protection heater is equipped with a ground terminal.

4. Design

Conduction heaters require less power than convection heaters because the conductive thermal properties of the metal are much better than air. The graph below shows the heat output at different block temperatures.

5. Technical parameters

All INTERTEC explosion-proof heaters can be delivered according to American NEC standards (CSA/NRTL/FM/UL) and are available also in cheaper safe area design.

 6. Options

 Ordering example: SL BLOCKTHERM DKA T3 AM

7. Temperature class restrictions

PTC-part (Ppositive Ttemperature Ccoefficient) increases electrical resistance with increasing temperature. High resistance means low power. The heating power is very low at high temperatures and therefore the maximum temperature of the specified temperature cannot be exceeded. The PTB certification requires that the ambient temperature coefficient of the enclosure cannot be less than K = 0.5 W / K. All INTERTEC protective cabinets meet this requirement.

8. Supply voltage

In addition to the above property, the PTC part acts as a varistor. It controls its resistance depending on the supply voltage. Rated Supply voltage can be from 110 V to 265 V for the same heater. Power output can be up to 15% higher than the chart shows.

9. Wiring diagram

Supply cable Silflex-EWKF 3x1,0 mm2, 1m long. Other lengths upon request (at extra cost).

10. Dimensions

11. Installation

The SL Blocktherm heating block conveys the heat through conduction. It must be mounted on a flat surface of the heat conducting material (e.g., metal). One screw is required for mounting.

Example: The MINITHERM DBA T4, which is attached to the Fisher Rosemount 3051H transmitter via an adapter, provides frost protection of the transmitter, manifold and impulse piping installed in the INTERTEC protective cabinet. External temperature is -25°C, SL Blocktherm DKA T3 can be installed up to -45°C.