Stemco Bulb & Capillary Thermostats provide precise, mechanical temperature control for electric sterilizers used in mushroom cultivation, food processing, and sanitation. Built with a liquid expansion sensing system and SPDT switching, these thermostats deliver reliable performance during long heat cycles in high-moisture, high-temperature environments.
If you’re an OEM or equipment builder looking for thermostats for electric sterilizers, contact us to discuss available models, temperature ranges, and mounting options.
How Our Thermostats Control Sterilizer Temperature
Each thermostat includes a liquid-filled sensing bulb, capillary tube, and a diaphragm-operated SPDT snap switch. The sensing bulb is installed inside the sterilizer chamber, usually near the heater or airflow path. As temperature rises, the liquid inside the bulb expands and pushes pressure through the capillary tube. This pressure moves the diaphragm, which actuates the switch to interrupt power to the heater once the setpoint is reached. When the temperature falls, the switch resets, allowing the next cycle to begin.
This mechanical method offers consistent temperature regulation without the need for digital sensors, software, or electronics that may degrade in high-humidity environments.
358 Series Thermostats for Electric Sterilizers
The 358 Series is a compact bulb & capillary thermostat designed specifically for electric sterilizer applications. It features a space-saving rear terminal layout and multiple standard mounting patterns to fit a variety of control enclosures.
Key features of the 358 Series:
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SPDT snap-action switch for ON/OFF heating control
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Available in fixed or adjustable temperature models
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Temperature ranges up to 600°F
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Mounting hole centers: 1.75″, 1.312″, or 28mm
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Copper, nickel-plated copper, or stainless-steel sensing bulbs
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Custom capillary tube lengths for remote sensing
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Tight differentials and close tolerances for precise chamber control
The 358 Series supports sterilizers that require stable temperature regulation across long cycles, frequent usage, and exposure to steam or condensation.
Applications for Thermostats in Electric Sterilization Equipment
Stemco Bulb & Capillary Thermostats are commonly installed in:
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Mushroom sterilizers for grain spawn and substrate preparation
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Electric food sterilizers used for jar, lid, and tool sanitation
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Steam sterilizers for small-scale food prep or processing
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Farm or off-grid sterilizer systems where mechanical controls are preferred
These thermostats support accurate temperature control over time. Their mechanical design is proven to perform in enclosed chambers without failure from heat, moisture, or cycling stress.
Designed for OEM Integration
Stemco thermostats are built for OEM integration into electric sterilizers. The SPDT contact arrangement offers dependable single-stage heater control. Adjustable or fixed setpoints are available to suit different sterilization requirements. Flexible capillary lengths, bulb materials, and mounting styles make it easy to adapt to your sterilizer design.
