Pressure Relief Valves

Lee Pressure Relief Valves are specifically designed to be the smallest valves available for safety relief applications. The smallest is only 3/16" in diameter and just over 1/2" long, and weighs only 1.5 grams. Seven different types are available, offering a wide range of cracking pressures and flow rates.

Lee PRI (Pressure Relief Insert)

Lee PRI Logo

These 0.187”, 0.250” and 0.281” diameter relief valves are constructed entirely of stainless steel and are available screened and unscreened. Built-in damping assures quiet operation. Cracking pressures for the 187 PRI range from 20 - 100 psid, and for the 250 and 281 PRI from 80-3600 psid

Momentum PRI

These 0.375” and 0.500” diameter relief valves use the patented “momentum free” design concept, which compensates for momentum forces that upset the normal force balance of a direct acting valve. These momentum forces are produced by localized pressure gradients resulting from velocity changes within the valve. These valves offer both linear and stable operation with minimal hysteresis. Both valves are available with cracking pressures from 50-500 psid.

Zero-Leak PRI

This 0.281” diameter valve is ideal for thermal relief and low flow hydraulic pressure relief applications where zero leakage is needed. Available cracking pressures range from 800 to 4700 psid.

High Pressure PRI

These 0.281” and 0.375” diameter relief valves are designed for applications where operating pressures and pressure spikes are too severe for conventional relief valves. Such conditions can lead to instability, erosion and structural damage of conventional relief valves. Both valves are available in a range of cracking pressures for system pressures up to 5,000 psi. .

High-Q PRI

The High-Q PRI pressure relief valve, sometimes referred to as an LRU (Line Removable Unit), is designed for applications that require both a high relief pressure and a high flow rate in a compact package. The valve is capable of relief pressures up to 5,400 psid and flow rates over 19 GPM. The valve uses a side inlet flow path to minimize the installation boss size and weight.