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Flow Restrictors

Flow Restrictors for Aerospace & Defense

The Benchmark Restrictor in the Aircraft Industry

Precision flow restrictors from The Lee Company have become an industry standard for manufacturers around the world. Flow restrictors are found in critical applications throughout an aircraft. This includes metering fuel to the engine, lube oil to gears and bearings, controlling the speed of actuators used for flight controls, deploying landing gear and utilities, or snubbing pressure pulses.

The Lee Company offers both single and multi-orifice restrictors to meet the needs of any application. Multi-orifice configurations may offer increased resistance to contamination and decrease the potential for erosion caused by cavitation. Lee Jets, Bender Jets, and Visco Jets are all 100% tested for bi-directional flow with tight tolerances, and come with an integral safety screen for added protection against debris and contamination. They are all constructed of stainless steel, capable of high operating pressures, and utilize the Lee expansion pin locking ends for easy installation and retention.

All products from The Lee Company are designed to be extraordinarily lightweight, but with strength far exceeding their size. Manufacturers will discover an extraordinarily resilient product that demonstrates exceptional performance in any environment. For more information, download our eBook, An Engineer’s Guide to Selecting a Flow Restrictor.

Lastly, The Lee Company has developed a simple system of defining fluid resistance of flow restrictors and other components. Based on Bernoulli’s equation, it allows you to calculate performance without needing to factor in coefficients of discharge and dimensional tolerances. It also allows the user to calculate the total effect of multiple restrictions in series or parallel. To learn more, visit the Lohm Laws page under our Engineering Tools section.

Lee Jet® Single-Orifice Restrictors

Although the Lee Jet® is the simplest restrictor in our product line, it’s also one of the most proven and reliable restrictors ever developed. Most notably used in the 1960s to supply oxygen to astronauts on the first moonwalk, it’s been integrated into almost every aircraft design since.

Standard Lee Jets are available in 53 Lohm ratings, ranging from 800 to 30,000 Lohms, calibrated within tolerance as low as +/- 2%. Lee High Watt and Lee Kilowatt Jets are intended for low Lohm (high flow) applications starting at 90 Lohms. High-pressure configurations are available for operating pressures up to 5000 psi.

Lee Bender Jet Multi-Orifice Restrictors

As the name suggests, Lee Bender Jets use multiple offset orifices in series. Each additional restriction causes an increased reduction in flow. This produces an effect that results in an increased minimum passage size for a given Lohm rate. The valve’s components are protected with two integral safety screens for bi-directional flow and are available calibrated to a ±5% tolerance in the range of 125 to 9500 Lohms.

Lee Visco Jet® Multi-Orifice Restrictors

The Lee Visco Jet® is one of our most unique innovations. It creates a highly complex fluid passage with a series of individual spin chambers and orifices. This provides an increase in flow passage as great as 25 times that of a corresponding (same Lohm rate) single-stage restrictor, with a corresponding reduction in velocity.

Visco technology offers multiple benefits, including increased resistance to contamination and reduced erosion. Its design prevents cavitation and creates a degree of viscosity compensation. To learn more about how Lee Visco Jet technology works, watch this short video.

Visco Jets are available in flow rates up to 313,000 Lohms in a 0.187 inch diameter cartridge and up to 2.2 million Lohms in a 0.43-inch diameter cartridge. There is no other product available that can provide this level of restriction with such a large minimum passage in such a tiny package.

Lee Axial Visco Jet® Multi-Orifice Restrictors

An evolution of the Bender Jet concept, Lee Axial Visco Jets don’t just bend but spin the fluid in alternating directions to create a more tortuous flow path. The result is a larger passage size than Bender Jets for a given Lohm rate, but a smaller passage size compared to Visco Jets. Increased resistance to contamination makes multi-orifice restrictors useful in systems that tend to have dirtier fluids, such as lubrication and fuel systems. Lee Axial Visco Jets are available in models ranging from 600 to 11,000 Lohms.

Support & Resources

Support & Resources from a Team that Speaks Your Language

The Lee Company has over 70 years of experience solving the aerospace and defense industry’s toughest tough fluid control problems. Explore our resources to learn more about the solutions we offer that can help you reduce costs while optimizing the performance of your aircraft or defense system. Check out these aerospace and defense-specific resources to learn more about what we offer.