Focus 7 - March 2002

HIGH TEMPERATURE BYPASS

When the process temperature is above 750°C the flame is self sustained and flame safeguard systems can introduce undesired shutdown with consequent long cooling and startup period.
A good solution is to bypass flame safeguard when the temperature is above 750°C, following the prescriptions of EuroNorms:

EN746-2:1997
5.2.6.3 HIGH TEMPERATURE EQUIPMENT

Flame supervision, either by means of a flame safeguard or by the operator, shall be provided during the start-up period when the processing chamber wall temperature is below 750 ° C.
Any flame safeguard shall comply with the requirements of 5.2.6.1.
Flame safeguards shall not be substituted by operator supervision unless the operator is capable of taking immediate corrective actions during the heat-up phase. The length of this heat-up phase shall be specified in the instruction handbook.
If the design and construction of the plant is such that, in the event of flame failure, the temperate of the processing chamber walls is likely to fall below 750 °C within 1 h, then an acoustical and visual alarm shall be fitted.

Bcr.1 is the easiest way to implement high temperature bypass for Burner Control Units Quad. An external signal supplied by temperature controller handles the bypass request. The plausibility of the request is controlled by Bcr.1 to avoid unattended operations.
This low profile, unexpensive piggyback board can be used in systems with remote control (either old TRAX or TraxBus) or with traditional wiring control.

- Flame bypass input from external temperature controller
- Flame bypass output (single wire to probe input)
- Thermostat input with configurable behaviour:
   > burner start/stop
   > burner pause (forcing prepurge)
- Aux relay output with configurable behaviour:
   > burner running
   > burner lockout
- Old Trax interface available

If you prefer not to receive FocusNews in the future, please send a blank email to :
Stop NewsLetter FOCUS .