Close Menu
Industries | Space | Products | Flow Restrictors

Flow Restrictors

Restrictors for Space

To the Moon and Beyond with Lee Restrictors

Lee flow restrictors have a storied history in spaceflight. When Neil Armstrong first walked on the moon in 1969, a screened restrictor – designed and manufactured by The Lee Company – metered the flow of oxygen between his spacesuit and his backpack. Since then, Lee restrictors have served in spaceflight applications around the solar system – and we hope to return our products to the moon’s surface in the near future.

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. Our Lee Visco Jets are available in Lohm rates up to 2.2 million (an equivalent orifice of 0.0006 inch) with a minimum passage of 0.005 inch in an envelope less than 0.6 inch long. These are often integrated into line mount fittings to control flow ratio in electrical propulsion. For more information, download our Tech Talk on selecting restrictors for space applications.

Lee Jets, Bender Jets, and Visco Jets are all 100% tested for bi-directional flow with tight tolerances. They come with an integral safety screen for added protection against debris and contamination. They feature all stainless steel construction and a high operating pressure capability.

All products from The Lee Company are designed to be extraordinarily lightweight, but with strength far exceeding their size. When restrictors are combined with bi-directional safety screens that prevent clogging and wear, manufacturers will discover an extraordinarily resilient product that demonstrates exceptional performance in any environment.

Over half of the products Lee supplies are designed for the unique needs of a specific application. Flow restrictors can be designed in custom envelopes such as line mount fittings, with unique flow rates or flow tolerances, constructed of special materials, and more.

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 a 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. 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 and Resources

Support and Resources from a Team that Speaks Your Language

To learn more about how to choose the right Lee restrictor for your space application and maximize its performance in the long-run, check out the resources below.