Blue M Friction Aire® industrial safety ovens provide a controlled heat source without heating elements, which eliminates atmospheric explosions and ignitions when working with hazardous Class 1, Group D materials. Class 1 atmospheres contain flammable vapors, and Group D materials include many solvents commonly used in finishing applications, such as lacquers and paints.
Typical Industrial Safety Oven Operating Characteristics
Models HS-1002, HS-1202 and HS-3802
Temperature range: +20°C above ambient to +150°C (302°F)
Typical air temperature uniformity at +100°C: 0.5°C
Run-up time: (no load) to +150°C: 120 minutes
Cool downtime: (no load) to +50°C: 30 minutes
Control accuracy: 0.5°C
Drift: (over 24-hour period)
at +50°C: 1.0°C
at +100°C: 0.75°C
at +150°C: 0.50°C
UL Listed
Average velocity: (adjustable)
Maximum: 400/FPM
Minimum: 100/FPM
Model HS-362
Temperature range: +20°C above ambient to +150°C (302°F)
Typical air temperature uniformity at +100°C: 0.5°C
Typical air temperature uniformity at +150°C: 1.0°C
Run-up time: (no load) to +150°C: 60 minutes
Cool downtime: (no load) to +50°C: 30 minutes
Control accuracy: 0.5°C
Not UL Listed
Drift: (over 24-hour period)
at +50°C: 1.0°C
at +100°C: 0.75°C
at +150°C: 0.50°C
Average velocity: (adjustable)
Maximum: 500/FPM
Minimum: 200/FPM
Models HS-1004, HS-1204 and HS-3804
Temperature range: +20°C above ambient to +260°C (500°F)
Typical air temperature uniformity at +100°C: 0.5°C
Typical air temperature uniformity at +200°C: 1.0°C
Run-up time: (no load) to +260°C: 140 minutes
Cool downtime: (no load) to +50°C: 30 minutes
Control accuracy: 0.5°C
Not UL Listed
Drift: (over 24-hour period)
at +50°C: 1.0°C
at +100°C: 0.75°C
at +150°C: 0.50°C
at +200°C: 0.50°C
Average velocity: (adjustable)
Maximum: 500/FPM
Minimum: 250/FPM
Three models have been listed by Underwriter's Laboratories for operation in Class 1, Group D hazardous locations. They are ideally suited for the testing and processing of hazardous materials, paints, solvents and lacquers. There are no heating elements in the chamber and no inherent hot spots to create potential danger. Tests show that load temperature follows closely behind chamber temperature. If the application calls for the processing of hazardous materials over extended periods, the load temperature and chamber temperature will be practically equal all of the time. When chamber and load reach complete equilibrium they will remain so indefinitely until the temperature is deliberately changed. Even if spillage of flammables inside the chamber occurs, danger is minimized since any surface the liquid encounters is only as hot as the interior environment.
This industrial safety oven is U.L. listed for Class I Group D operation and is the first and only industrial safety oven to have this listing.
How it Works
The ovens regulate temperature inside the chamber of the industrial safety oven by using a high velocity airflow system to generate heat, not a centralized heating element. The absence of a heating element eliminates an ignition source when working with atmospheres containing flammable vapors. A blower moves the air around the chamber to create turbulence and friction, which creates an even heat.
The temperature can be set using one of Blue M's standard control systems. A temperature-sensitive bellows regulates how much ambient air enters the blower. As the temperature rises to the setpoint, the bellows expand to open the control gate. Sharp temperature curve-off and temperature stabilization occurs as more air enters the system.
The by-pass damper can be set to a horizontal position restrict the air flow through the blower to minimize the amount of heat generated for control at lower temperatures. When the by-pass damper is set to a vertical position, the air circulates a maximum velocity for maximum heat.
While the system requires a large amount of air volume to generate heat, most of the air passes through a by-pass chamber that surrounds the work chamber. A small percentage of air passes through the inner chamber.
Uniform Temperature
Because the Friction-Aire uses airflow to heat the oven, the temperature remains constant. The chamber temperature matches the oven's air temperature, thereby eliminating temperature stratification and hot spots.
Natural Temperature Interlock
If the air circulation stops for any reason, such as a blower failure, the temperature inherently drops. No dangerous temperature runaway conditions exist.
Because the industrial safety ovens lack a heating element, no timed purged cycle is necessary at start-up to clear the high vapor concentration. A high vapor level initially occurs due to the rapid evaporation of the liquid, and could ignite in ovens that use a heating element.
Built in Over Temperature Protection
A self-powered and self-sensing bellows system provides non-electrical over temperature protection. If the main control fails, the bellows will lock the exhaust vent open to quickly drop the temperature.
After the over temperature protection trips, the vent must be manually closed before operations can continue.
Fast Cool Down Rates
Typically, an empty oven will drop from 150°C to 50°C in 30 minutes.
Cost-Effective
The Friction Aire's design requires less maintenance and service because there are fewer components.