BSTW Safety Temperature Monitor, BTB/BSTB Safety Temperature Limiter16 A fail-safe

Certificates

  PTB 03 ATEX 1180
 DNV E-10452
  NEPSI GYJ11.1605
 GOST R POCC DE.ME92.B02734
 No. 903
 GOSPROMNADZOR 11-02-0015-2012

Ex protection type

 II 2G Ex ed IIC T6, T5
 II 2D tD A21 IP65 T 80 °C, T 95 °C

Ambient temperature

-20 °C standard
-40 °C/-55 °C on request
Max. sensor temperature: up to +345 °C
see datasheet

Description

The 16 A Ex temperature monitor BSTW/temperature limiter BTB/BSTB are change-over controllers housed in an Ex e certified polyester enclosure.

Heaters, fans, motors and other equipment are energised and de-energised by means of this thermostat when specific temperature ranges are exceeded. These devices can also be used to control the temperature in air or on various surfaces. The fail-safe temperature limiter BTB and the fail-safe temperature limiter BSTB are produced with restart lockout, resetting (reopening) is only possible at the device.

Function

Any change in temperature at the sensor bulb causes a change in the volume of fluid in the measuring system, which in turn results in a movement of the diaphragm membrane. This membrane is connected to a mechanical device that activates a microswitch. If the temperature at the sensor bulb exceeds the pre-set value, terminals 1 and 4 are opened.

The BTB and BSTB devices ?lock-out? permanently if the set temperature is exceeded. After a temperature decrease of about 9 % below the set value, both BTB and BSTB can be re-set manually. If there is a rupture or break in the sensor tube (leakage), then the switch remains permanently open (fail-safe). If the temperature falls below the minimum setting, the autocontrol opens the circuit but closes again on temperature rise.