Car Thermostat rubber valve

Core Functions

1. Temperature Regulation
   • Automatically adjust valve opening based on medium temperature changes to control fluid circulation paths (e.g., large circulation vs. small circulation), maintaining stable system temperatures.
   • Example: In automotive engine thermostats, rubber valves close the main circulation channel at low temperatures, allowing coolant to circulate only within the engine (small circulation) for heating. When the set temperature is reached, the rubber expands or deforms to open the main channel, engaging the radiator for large-circulation cooling.
2. Sealing and Buffering
   • The elastic sealing surface of rubber closely fits the valve seat to prevent leakage. It also buffers mechanical impacts during opening/closing, reducing wear and noise.
3. Fluid Corrosion Resistance
   • Resistant to ethylene glycol, additives in coolant, and chemical substances in industrial media, ensuring long-term use without corrosion or swelling.

Typical Structure and Working Principle

Structural Components

• Rubber Valve Disc/Diaphragm: The core actuating component, driven by temperature-sensitive materials (e.g., paraffin temperature-sensing elements in rubber diaphragms) or directly utilizing the thermal expansion/contraction properties of rubber.
• Metal Skeleton: Provides structural support to prevent excessive rubber deformation (some designs include springs for auxiliary reset).
• Valve Seat/Housing: Usually made of metal or engineering plastic, forming a sealing interface with rubber components.

Working Principle

1. Heat-Driven Type (Common in Automotive Thermostats)
   • A temperature-sensing element (e.g., paraffin pellet) expands with rising temperature, pushing the rubber diaphragm or valve disc against spring force to gradually open the main valve and increase fluid flow.
   • When the temperature drops, the rubber resets elastically or the spring force drives the valve to close, reducing flow.
2. Shape Memory Type (For Special Industrial Scenarios)
   • Uses shape memory rubber materials that trigger deformation at preset temperature thresholds to achieve automatic valve opening/closing (e.g., high-temperature emergency shut-off valves).