What valve opens if working pressure exceeds a predetermined maximum value?

The valve that opens if the working pressure exceeds a predetermined maximum value is a pressure relief valve. This type of valve is designed specifically to protect systems from overpressure conditions. When the pressure in the system rises above a set threshold, the pressure relief valve opens to allow excess pressure to escape, thereby preventing potential damage to the equipment or devices connected to the system.

A pressure relief valve is crucial for safety and operational integrity. It helps maintain safe operating conditions by diverting excess pressure away from sensitive components. The valve typically resets itself once the pressure returns to acceptable levels, ensuring ongoing protection.

In contrast, a safety valve also operates under similar conditions but may function at a specific discharge rate or is designed for a specific service (e.g., steam). While both serve safety purposes, the terminology can differ depending on the system's application.

Regulating valves, on the other hand, are designed to maintain a desired flow or pressure level within a system rather than opening purely as a function of exceeding maximum pressure. Control valves (such as solenoid or motor-operated valves) are used to regulate the flow of fluids based on feedback from the system conditions and do not operate on maximum pressure thresholds.