PRODUCT DATA SHEET HIGH PRESSURE 250 PILOT OPERATED CHEK® The Lee Company’s new High Pressure 250 Pilot Operated Chek is the latest addition to Lee’s line of miniature check valves. This valve acts like a normal check valve until pressure is applied to the pilot port, which then allows flow in the direction that would normally be blocked. This new valve is ideal for high pressure hydraulic applications with system pressures up to 5000 psi. The maximum restriction when piloted open is only 300 Lohms. The High Pressure 250 Pilot Operated Check is available in forward and reverse free flow configurations, and the metal components are constructed entirely of stainless steel for durability and long life. Nominal weight is just 7 grams. Each Chek is 100% tested and inspected to ensure reliable, consistent performance. ■ Designed for System Pressures up to 5000 psi ■ 300 Lohms max. when Piloted Open ■ Weighs only 7 grams ■ 100% Tested and Inspected ■ Endurance Tested to 500,000 Cycles ■ Two Compression Seal Materials ■ Fast Acting PIN xx- XX = .92 FORWARD/1.02 REVERSE INSTALLATION HOLE 1.47 MIN — 30 Valve performance on MIL-PRF-83282 at 85°F. 1 drop = 50 pL ^ CHECKED OR PIL0TED FLOW FREE FLOW See reverse side for Liquid Lohm Laws.

LOHM LAWS (liquids) Every engineer will be interested in our simple system of defining the fluid resistance of Lee hydraulic components. Just as the OHM is used in the electrical industry, we find that we can use a liquid OHM or "Lohm" to good advantage on all hydraulic computations. When using the Lohm system, you can forget about coefficients of discharge and dimensional tolerances on drilled holes. These factors are automatically compensated for in the Lohm calculations, and confirmed by testing each component to establish flow tolerances. The resistance to flow of any fluid control component...