What are the common safety interlock devices for fixed pressure vessels?

The commonly used safety interlock protection devices for stationary pressure vessels are mainly the following: 1. **Safety valve**: It automatically opens to release pressure when the pressure inside the vessel exceeds the set value, thereby preventing overpressure. 2. **Pressure gauge**: Displays the pressure inside the container in real time, facilitating monitoring. 3. **Blowout disc (explosion vent)**: It ruptures to release pressure when overpressure occurs, and is typically used in situations where safety valves are not suitable. 4. **Level gauge**: Monitors the liquid level in the container to prevent dangers caused by it being too high or too low. 5. **Thermometer or temperature sensor**: Monitors temperature to prevent pressure changes caused by abnormal temperatures. 6. **Emergency shut-off device**: Quickly stops the flow of the medium in and out in case of leaks, overpressure, or other abnormalities. 7. **Interlock control system**: It is usually connected to sensors for pressure, temperature, liquid level, etc., to automatically trigger actions such as stopping the pump and closing valves. 8. **Overflow protection device**: Prevents shocks or hazards caused by excessive flow rates of the medium. These devices work together to ensure that pressure vessels operate within safe limits and prevent accidents. The specific configuration must be determined based on the container’s purpose, the characteristics of the medium, and regulatory requirements. .

The safety interlock device for pressure vessels is simply a safety interlock device; there’s nothing more to it. The purpose is to prevent misoperations; anything that meets the requirements for safety interlock devices specified in the design documents can be considered a safety interlock device. Generally, it is a combination of multiple devices. Technical specification requirement: (1) The system shall start operating at increased pressure only when the quick-opening door reaches the predetermined closed position ； (2) The quick-opening door can be opened only after the internal pressure of the pressure vessel has been completely released. Pressure vessels equipped with safety interlock devices are known as quick-opening pressure vessels, and a R1 certificate is required to operate them. There are various ways to implement such safety interlocks; typical devices include sterilizers and autoclaves. Existing sterilizers are generally controlled by a main board and are equipped with limit switches, pressure sensors, and solenoid valves, and autoclaves work in a similar manner. To meet the technical specifications, the safety interlock devices used by different manufacturers vary greatly, and it is difficult to explain them in words. According to Article (1) of the technical specifications, control is generally achieved through limit switches; without these switches in the correct position, the circuit cannot be connected and the equipment cannot be started. However, limit switches are prone to damage, and their accuracy declines in harsh environments, thus posing safety risks. Control can also be achieved via latches, which are used in autoclaves – quick-release blind flanges are usually of this type. But this method does not allow for control of pressure increase, and strictly speaking, it does not meet the requirements of the technical specifications ； According to Article (2) of the technical specifications, control is generally carried out via the main board; there is a pressure-controlled locking mechanism that remains in the locked position at all times. The latch of the quick-release blind flange is held in place by the internal pressure, keeping it locked as long as there is pressure present. The most crucial factor in determining whether safety interlock devices can ensure safety is whether operators check their compliance in accordance with laws and regulations. This is especially true for equipment used in harsh environments such as autoclaves and vulcanization tanks, which require regular inspections by operators. If the personnel lack the necessary professional knowledge, no matter how good the interlock devices are, they cannot guarantee safety.