The Lee Company offers a wide range of products specialized for the space industry, including PRI/Check valves that combine the function of a relief valve and check valve in series into one compact product. Additionally, almost all Lee products can be supplied in a variety of unions or adapters as line removable units.
Like all Lee products, these components are tested under a rigorous quality management system and designed for high reliability, allowing them to stand up against the pressures, temperatures, and environments that characterize spaceflight applications.
Over half of the products we offer are designed for the unique needs of a specific application. The products can be designed in custom envelopes and configurations with unique operating pressures, flow rates, materials, and more. Contact your local Lee sales engineer to discuss your specific needs.
Lee PRI®/Chek® Valves combine the function of a reverse flow pressure relief valve in parallel with the function of a check valve with free flow in the forward direction into one easily installed insert. The relief valve function features a rugged Tungsten Carbide ball and a 440C seat for durability and long life. The remaining components are constructed entirely of stainless steel. The valves are available in a range of relief flow cracking pressures for system pressures up to 5000 psi.
The 281 PRI/Chek Valves are available with or without integral safety screen filters. The unscreened version has a maximum restriction of 300 Lohms in the free flow direction and is available in nine different standard relief flow cracking pressures up to 3600 psid. The screened version has a maximum restriction of 550 Lohms in the free flow direction and is available in 15 different standard relief flow cracking pressures up to 5900 psid. The 375 PRI/Chek Valve has a maximum restriction of 220 Lohms in the free flow direction and is available in seven different standard relief flow cracking pressures up to 5400 psid.
Virtually every 0.187, 0.250, and 0.281 inch diameter Lee insert is offered already installed in appropriately sized flared, flareless, or dynamic beam seal unions. These unions are made of 304 stainless steel (code “J” in military standards) or 6AL-4V Titanium (code “T”). All Lee Unions have a unique hex wrench arrangement to distinguish them from simple unions and permanent external marking to identify the insert.
The configuration of these unions has been carefully chosen to accommodate most of the 0.187, 0.250, and 0.281 inch Lee inserts, and yet maintain both minimum envelope and weight. These units incorporate the high-root radius UNJF threads to minimize stress concentrations with Class 3A tolerances. All fitting-end dimensions are, except for the internal diameters, in general accordance with the appropriate AS4375E4 and E6, AS4395E04 and E06, and AS85720/1-04 and –06 specifications.
Every Lee Union with an insert installed is proof pressure tested; flared and flareless to 6000 psid, and dynamic beam seal to 16,000 psid. Maximum working differential pressure is a function of the particular Lee insert specified (refer to the appropriate insert section).
All of the standard cartridge 43 and 68 Series Visco Jets and standard Axial Visco Jets are also available built into unions with AS4395E04 flared ends. Different style or size ends are available on a special order basis.
Partner with The Lee Company and get much more than just a supplier of top-quality fluid control products. Our reliable technical support team is available every step of the way to help you find solutions, maximize productivity, and drive efficiency across your operations. Check out these resources specific to space industry applications to learn more.