ASG Measurement & Control Group

Measurement & Control Group

Customised Laboratory Instrumentation, Data Acquisition Systems, Design Capabilities

Godbert - Greenwald Furnace

• Hazard Screening Test Apparatus
• Complete with Temperature Controller & Trip Facility
• Automatic Air Charging System for Powder Injection
• Remote Control facility for Discharging the Air Reservoir

Description of the Godbert-Greenwald Furnace:

The furnace comprises of a heated Silica tube capable of reaching temperatures of 1000 DegC. Built-in control, trip and sample thermocouples are used to measure the internal temperature of the Silica tube. A sample powder injection module is close coupled to the furnace inlet and is mounted via the furnace sidewall assembly, for compactness. The bottom of the furnace is open to atmosphere allowing combustion products to vent into the fume cupboard. A stainless steel mirror is placed at a suitable angle and underneath the furnace to allow visual monitoring of the sample as it enters the heated Silica tube. The furnace, stand and associated support assemblies are manufactured from stainless steel, whilst the sample powder injection  module is manufactured from Brass.

Air Input Assembly

In order to inject the sample powder into the heated tube assembly a reservoir is pressurised via a regulated air line and then vented into the powder injection module. This pulse of air carries the sample powder into the heated Silica tube.

The air input assembly comprises of an air reservoir complete with inlet / outlet valves and pressure gauge. This assembly can be assembled and customised for your installation as required.

CONTROL / MONITORING INSTRUMENTATION

Control instrumentation for the Godbert Greenwald furnace has been split into three modules, Temperature control / Air Reservoir Control, Heater Power Control and Remote Control Trigger.

Temperature Control / Air Reservoir Control

This module is responsible for setting and controlling the Silica Tube internal wall temperature. It also monitors over temperatures and automatically removes power from the heating elements of the Silica Tube if over temperatures are detected. The inside wall of the Silica Tube is also monitored, hence, the surface temperature of the tube is known. Eurotherm controllers and indicators are used for all control and display functions.

Air Reservoir Control

Manual control over the air inlet and outlet valves to charge and discharge the air reservoir can be carried out via this instrument. A timer function has also been employed to give greater control over the open time of the reservoir discharge valve, therefore allowing the valve to fully open or partially open to discharge the air reservoir.

Power Control Module

The power control module comprises of a mains transformer and solid-state relay, specifically for control of the Silica Tube heating elements. This module can be mounted locally to the furnace as required.

Remote Control Trigger Module

This module allows the operator to open the reservoir outlet valve whilst looking for an event inside the Silica Tube via the furnace mirror. A push button located on the remote trigger module is used to open the air reservoir outlet valve. Addition features located on the remote module allow the operator to manually charge the air reservoir and to adopt a semi-automatic mode where the air reservoir is charged with air after each venting.