Commercial and industrial hot air tunnel dryers, used for shrink wrapping and drying, rely on precise temperature control. This control is achieved with a combination of double bulb and capillary thermostat switches and snap disc thermostat switches. These components work together to maintain optimal temperatures and ensure safety. Below, we explore how these switches function and their technical specifications. For detailed information, click the diagram on the right.
Typically, systems use part numbers P/N 351-253890 (double bulb and capillary thermostat) and P/N 351-254243. For more on monitoring temperature in hot air tunnels or using tunnel dryer switches, continue reading.
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Double Bulb and Capillary Thermostat Switch
The Double Bulb Thermostat Switch controls heating elements by sensing both temperature and current draw. As the temperature reaches the set point, the switch shuts off the heating elements to prevent overheating and reactivates them once the temperature drops, ensuring consistent operation.
- Temperature Sensing: The primary bulb monitors the tunnel temperature. When the temperature reaches the maximum set point, the fluid in the capillary tube expands, creating pressure that triggers the switch to shut off the heating elements.
- Safety Mechanism: A secondary bulb monitors current draw, which generates heat. If the current draw becomes too high, the capillary switch activates to shut down the heaters, preventing overheating.
- Temperature Range: Our capillary thermostat switches operate between 0°-700°F, with a maximum ambient temperature of 250°F. These thermostats can be manually or automatically reset to address temperature malfunctions. They come with fixed or adjustable temperatures.
Technical Specs:
- Operating Temperature: 0°-700°F
- Max Ambient Temperature: 250°F
- Reset Options: Manual and automatic
- Temperature Settings: Fixed or adjustable
For more information about our capillary thermostat switches, visit the product page.
Snap Disc Thermostat Switch
Snap disc thermostat switches provide additional safety by sensing high temperatures in the airstream. Calibrated to the system’s maximum temperature, they shut down the heating elements to prevent critical events. These switches can be manually reset, requiring human intervention, or automatically reset based on a pre-determined temperature.
- High-Temperature Detection: Placed in the airstream, the snap disc thermostat detects when temperatures exceed safe operating limits.
- Safety Shutdown: The switch opens the circuit, cutting power to the heating elements to prevent hazards.
- Reset Mechanisms: Configured for either manual or automatic reset based on system requirements.
Technical Specs:
- Operating Temperature Range: -50°F to 450°F
- Switch Types: 1/2″ or 3/4″ bi-metal snap disc styles or digital switching solutions
- Customization: Various temperature settings, tolerances, differentials, terminals, and mounting options
For more information on our standard snap disc thermostat options, click here to visit the Senasys website.
Double bulb and capillary thermostat switches, along with snap disc thermostat switches, are essential for maintaining precise temperature control and safety in commercial and industrial hot air tunnel dryers. Understanding their operation and technical specifications is needed for selecting the right components.