An annealing tower over-temperature automatic power reduction protection control system

Abstract

The application discloses an annealing tower over-temperature automatic power reduction protection control system and belongs to the technical field of grain processing equipment. The system comprises a redundant over-temperature detection unit and an over-temperature automatic power reduction protection control logic. The redundant over-temperature detection unit is composed of at least two temperature sensors independent of a main temperature control loop; the over-temperature automatic power reduction protection control logic is electrically connected with the redundant over-temperature detection unit and power switches of each heating device; when at least two temperature sensors simultaneously detect that the temperature in the tower exceeds a preset over-temperature threshold value, the power supply of the heating device is automatically cut off and the heat exhaust door is opened to forcibly ventilate and cool down, and the response time is less than or equal to 10 seconds. The system provides over-temperature safety protection independent of the main control system for the annealing tower and prevents material quality deterioration caused by temperature control failure.

Description

Technical Field

[0001] This invention belongs to the technical field of grain processing equipment, specifically relating to an over-temperature safety protection and control system for an annealing tower. Background Technology In the annealing process of grain flour, different varieties have different safe upper limits for temperature. Varieties containing gluten protein have strict temperature requirements for gluten protection, as gluten protein begins to undergo irreversible thermal denaturation at 54-56℃. Other varieties, such as corn starch, potato starch, and bean starch, will also experience irreversible quality degradation when their starch granule structure and active ingredients exceed their respective safe thresholds. The normal operating temperature of the annealing tower is usually very close to these safe thresholds. If the temperature control system malfunctions—such as heating relay sticking, temperature sensor drift, or main controller program freezing—the temperature inside the tower may surge from the set value to the dangerous range within minutes, leading to quality degradation or even scrapping of the entire batch of material. Traditional annealing towers typically rely on a main temperature control loop for over-temperature protection—when the main temperature sensor detects over-temperature, the main controller issues a power reduction command. However, this protection has a fatal flaw: it shares the same hardware as the root cause of temperature control failure. When the heating relay sticks and continues heating, the power reduction command issued by the main controller cannot be executed; when the main temperature sensor experiences positive drift, the temperature read by the main control system is lower than the actual temperature, and the over-temperature protection will not be triggered. Therefore, a redundant over-temperature protection device independent of the main control system is a necessary configuration to ensure the safety of the annealing process. Summary of the Invention Purpose of the invention An automatic over-temperature protection and control system for annealing towers, independent of the main temperature control loop, is provided. Technical solution This system comprises two parts: a redundant over-temperature detection unit and an automatic power reduction protection control logic for over-temperature protection. The redundant over-temperature detection unit consists of at least two temperature sensors independent of the main control loop. Upon confirmation of over-temperature by the redundant over-temperature detection unit, the protection control logic automatically cuts off the heating power and forces ventilation for cooling. The over-temperature threshold can be preset according to the thermosensitive characteristics of different materials; one preferred threshold is 54℃, specifically designed to protect the gluten activity of gluten-containing grain flour. Core Mechanism The redundant over-temperature detection unit's temperature sensors are installed and operate independently of the main temperature control loop, possessing independent power supply and signal transmission channels. Even if the main control system completely fails, the redundant over-temperature detection unit can still function normally. The protection control logic employs a "two-out-of-two" voting mechanism—over-temperature protection is only triggered when at least two independent temperature sensors simultaneously detect that the tower temperature exceeds a preset threshold, avoiding false triggering due to a single sensor failure. After triggering, the system automatically cuts off power to all heating devices while maintaining continuous operation of the circulating fan and opening the exhaust damper for forced ventilation and cooling. Hot air inside the tower is rapidly exhausted through the exhaust damper under the drive of the circulating fan, and the temperature drops back to a safe range within 30 seconds. After the over-temperature protection activates, the system enters a locked state, requiring on-site confirmation of fault resolution and manual reset by the operator to prevent automatic reset from causing the temperature to exceed the limit again. Beneficial effects (1) Redundant detection is independent of the main control circuit, eliminating the hidden danger of protection failure caused by main control failure. (2) The "two-out-of-two" voting mechanism prevents sensor false triggering. (3) Forced ventilation accelerates cooling after heating is cut off, and the safe temperature is restored within 30 seconds. (4) Manual reset lock prevents temperature fluctuations caused by repeated automatic restarts. (5) The over-temperature threshold can be flexibly preset to adapt to the safety temperature requirements of different varieties of grain powder. Detailed Implementation Example 1 Two independent thermocouple temperature sensors, separate from the main control circuit, are installed above the material layer inside the annealing tower, with independent power supply and signal transmission. The protection control logic sets the over-temperature threshold to 54℃, and the voting mechanism is "two out of two". The annealing tower is normally set to a temperature of 52℃. During one operation, the heating relay in the main control circuit malfunctioned, causing the heating device to continue heating at full power. Although the main control circuit issued a power reduction command, it could not be executed, and the temperature inside the tower began to rise. When both redundant sensors simultaneously detected a temperature exceeding 54℃, the protection control logic automatically cut off the power to the heating device within 3 seconds, while maintaining the operation of the circulating fan and opening the exhaust damper. The temperature inside the tower dropped below 52℃ within 25 seconds. After the operator checked and confirmed that the fault had been resolved, they manually reset the system, restoring normal operation. Comparative Example 1 (Reliant on main control circuit protection, failure) The redundant over-temperature detection unit was eliminated, and over-temperature protection relied solely on the main temperature control loop. After a heating relay sticking fault occurred, the main control loop issued a power reduction command but failed to execute it, allowing the temperature to continue rising to 62°C. Irreversible denaturation of the gluten protein occurred, rendering the entire batch of material unusable. This demonstrates that redundant protection independent of the main control loop is a necessary condition for ensuring annealing safety. Comparative Example 2 (Single sensor triggering, frequent false alarms) Only one independent temperature sensor was used, and the protection logic was "one-out-of-one". During operation, the sensor experienced instantaneous signal spikes due to electromagnetic interference, which falsely triggered the over-temperature protection, causing three interruptions to normal production. This proves that the "two-out-of-two" voting mechanism is a necessary design to prevent false triggering. Comparative Example 3 (Automatic Reset, Temperature Oscillation) After the over-temperature protection tripped, the system automatically reset and resumed heating. However, the heating device malfunction persisted, and the temperature rose again, triggering a secondary protection. This cycle repeated three times, causing the material to fluctuate between high and low temperatures, resulting in partial denaturation of the gluten protein. This demonstrates that manual reset and locking are necessary measures to prevent temperature fluctuations. Industrial applications This system is suitable for over-temperature safety protection in annealing towers, especially for annealing processes involving gluten-containing grain flour. The over-temperature threshold can be flexibly set according to the thermal sensitivity characteristics of different materials. Redundant temperature sensors need to be calibrated regularly to ensure independence and measurement accuracy. Troubleshooting records after over-temperature protection activation must be included in the production safety file.

Claims

1. An automatic power reduction protection control system for annealing tower overheating, characterized in that, include: a. Redundant over-temperature detection unit: consisting of at least two temperature sensors independent of the main temperature control loop, wherein the temperature sensors are installed above the material layer inside the annealing tower to monitor the air temperature inside the tower in real time; b. Over-temperature automatic power reduction protection control logic: It is electrically connected to the redundant over-temperature detection unit and the power switches of each heating device. When at least two temperature sensors detect that the temperature inside the tower exceeds the preset over-temperature threshold at the same time, it automatically cuts off the power supply of the heating device and opens the heat exhaust damper for forced ventilation and cooling. The response time is ≤10 seconds. After the over-temperature protection is activated, the operator must manually confirm the reset before heating can be restarted.

2. The system according to claim 1, characterized in that, The preset over-temperature threshold is 54°C, which is used to protect the gluten activity of gluten-containing cereal flour.

3. The system according to claim 1, characterized in that, The temperature sensor is a thermocouple or a Pt100 platinum resistance temperature sensor. The redundant over-temperature detection unit operates independently of the main temperature control loop and has its own power supply and signal transmission channel.

4. The system according to claim 1, characterized in that, The automatic power reduction protection control logic for over-temperature keeps the circulating fan running after the power to the heating device is cut off, so that the hot air in the tower is quickly discharged through the heat exhaust damper, and the temperature in the tower drops back to below the preset over-temperature threshold within 30 seconds.

5. An annealing tower employing the system described in any one of claims 1-4, characterized in that, No material quality deterioration events caused by overheating occurred during the continuous operation of the annealing tower.