Liftoff is one of the most sensitive stages of spaceflight. Thrust vectoring systems make thousands of tiny automatic adjustments in order to create what looks, to the outside observer, like a clean arc from the landing pad into the upper atmosphere. During the first few critical minutes from launch to stage separation, it’s important to rely on lightweight and reliable components that have been tested across hundreds of launches and decades of manned and unmanned spaceflight.
The Lee Company makes four kinds of flow metering valves which are commonly used in spacecraft hydraulic systems. This range of valves provides additional functionality for applications when a basic flow restrictor is not enough.
Lee Restrictor Cheks combine the function of a restrictor in series with a check valve into one miniature package. This provides considerable size and weight savings with no loss in performance. Lee directional flow controls provide metered flow in one direction and free flow in the opposite direction. Dual metering flow controls offer different metered flow rates in each direction. By contrast, Lee Floserts – while still incredibly small and lightweight – provide a constant flow over a wide range of differential pressures by incorporating both fixed and variable metering orifices.
In short, Lee flow metering valves generally combine the function of two components in a single package, but they can provide functionality that’s greater than the sum of the combined parts. As with all Lee valves, these robust products offer precise performance in miniature, lightweight envelopes. They are available in a variety of sizes and configurations to meet the specific needs of an application. This makes them ideal for pressurization, propulsion, purge systems, and thrust vector control.
The Lee Restrictor Chek® is a miniature 0.187 inch diameter valve that provides metered flow in one direction and no flow in the other direction. These components are functionally equivalent to a check valve in series with a flow restrictor. Combining these two products in a single package equates to significant savings in size, weight, and cost. The components are available standard in metered Lohm rates from 1000 – 10,000 Lohms, with an integral safety screen to protect the orifice.
Lee directional flow controls provide metered flow in one direction and free flow in the opposite direction. Occasionally referred to as one-way restrictors, these components are functionally equivalent to a check valve in parallel with a flow restrictor. They are available in four diameters (ranging from 0.87 to 0.500 of an inch) with metered Lohm rates from 40 up to 20,000 and rated for 3000, 5000 and 8000 psi systems. Again, these flow controls allow manufacturers to achieve multidimensional savings by combining two components into one compact package.
The Lee Company’s dual metering flow control valves are two-way restrictors that allow a designer to specify a different metered flow rate in each direction. These valves are ideal for high-pressure hydraulic applications with system pressures up to 5000 psi. They feature all stainless steel construction for durability and long life and are available in 0.187 and 0.281 inch diameter models. Each Lee Dual Metering Flow Control is 100% tested in both flow directions to ensure reliable, consistent performance.
Because each direction can be specified differently, our dual metering flow controls can achieve a nearly infinite combination of metered flow rates. As such, all of these components are supplied as custom items to meet the specific needs of an application.
For advanced applications, aircraft and defense manufacturers may wish to consider Lee Floserts. This is a pressure compensated flow control – in other words, the flow will remain constant across a wide range of differential pressures. A variable metering orifice automatically adjusts by sensing the flow rate in terms of differential pressure across a fixed orifice. Metered flow rates from 0.01 GPM up to 5 GPM are available. Floserts are available with the Lee locking end for installation in diameters from 0.250 to 0.500 as well as a 0.687 inch threaded configuration. High-pressure versions for operating pressures up to 5000 psi are available.
Learn which of our Lee flow metering valves will work best for your spaceflight application. Start by checking out the resources below.