How does the Oven Mechanical Timer achieve temperature control?

The Oven Mechanical Timer achieves temperature and time control of the baking process through the synergy of precise mechanical structure and thermostat. Its core function is not to adjust the temperature directly, but to ensure that the oven maintains a stable thermal environment within the set time through the timing mechanism and the temperature control system. The following is an explanation of the working principle of the mechanical timer, the cooperation mode with the thermostat, the temperature control limitations and the key points of operation.
The mechanical timer consists of three parts: the power component, the release component and the timing trigger device. The power component adopts the spring energy storage design. When the user manually tightens the spring, the one-way mechanism ensures that the spring can only be tightened and cannot be relaxed in the reverse direction. The release component converts the rotational force of the spring into uniform motion through a multi-stage gear speed change system. Among them, the cooperation between the escapement wheel and the hairspring is particularly critical-the escapement claw periodically releases the gear to make the gear system rotate at a constant speed. This design draws on the principle of mechanical clocks to ensure timing accuracy. The timing trigger device is controlled by the gear transmission angle. When a specific gear rotates to a preset position, it triggers a mechanical or electrical signal to achieve automatic power-off or alarm function after the timing ends. For example, when the user sets the timer knob to the 30-minute scale, the spring tension drives the timing gear train through the gear set until the trigger mechanism acts to cut off the power supply.
As the core of oven temperature control, the thermostat forms a clear division of labor with the mechanical timer. The thermostat has a built-in bimetallic strip or thermistor sensor to monitor the oven cavity temperature in real time. When the actual temperature is lower than the set value, the thermostat closes the circuit and turns on the heating element; when the temperature reaches the threshold, the bimetallic strip cuts off the circuit due to thermal expansion and deformation, forming an "on-off" cycle control. The mechanical timer plays a timing role in this process: after the user presets the baking time, the timer starts to release the spring power, and the gear train runs at a constant speed until the trigger point. For example, when baking a cake, the thermostat maintains the cavity fluctuation within the range of 180℃±10℃, and the timer ensures that the heating process lasts for 40 minutes. The two work together to ensure the baking effect.
Mechanical timer temperature control has two core limitations: the first is the large temperature error. Ordinary mechanical thermostats have low sensitivity, and the temperature fluctuation range is usually ±15-20°C, which is difficult to meet the needs of precision baking; the second is the temperature control response lag. Due to reliance on mechanical triggering and bimetallic deformation, the thermostat responds slowly to temperature changes, and short-term over- or under-temperature phenomena may occur. In contrast, the electronic temperature control system uses PID algorithm and NTC thermistor to compress the temperature error to within ±3°C, and the response speed is increased several times. For example, when baking macarons, mechanical temperature control may cause uneven coloring of the sugar, while electronic temperature control can accurately maintain a constant temperature of 160°C.