Cracking Pressure

on . Posted in Fluid Dynamics

Cracking pressure is the minimum pressure required to open or "crack" a pressure relief valve, safety valve, or pressure regulating valve.  These valves are designed to release excess pressure from a system to prevent overpressurization, which could lead to equipment failure, leaks, or even catastrophic events.  Cracking pressure is important for valves because it determines the point at which they start to open and allow fluid to flow out of the system, relieving the pressure.  Once the cracking pressure is reached, the valve starts to lift or open, allowing the pressurized fluid to escape until the pressure decreases below a certain level, at which point the valve closes again.

For pressure relief valves and safety valves, the cracking pressure is typically set at a level slightly above the normal operating pressure of the system.  This ensures that the valve remains closed during normal operation but opens when pressure rises above safe levels.  The cracking pressure is a key factor in determining the overall performance and safety of pressure relief systems, especially in industries where pressure vessels or piping systems are involved, such as petrochemical, pharmaceutical, and manufacturing industries.

In pressure regulating valves, the cracking pressure is the pressure at which the valve starts to allow fluid to flow to maintain a constant pressure downstream.  These valves are often used to ensure that certain parts of a system are supplied with fluid at a consistent pressure, regardless of fluctuations in the supply pressure.

P D Logo 1

Tags: Pressure Valve