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Pyrovalves (also known as pyrotechnic valves) have long been a staple in defense systems, particularly in missile and munition launcher applications.
Traditional pyrovalves come with notable drawbacks: they’re single-use, generate shock and debris, and require complex qualification and handling procedures. Modern defense programs are shifting toward safer and more cost-effective alternatives.
Exploring alternatives to your current pyrovalve? This article shares best practices to help guide your design: what to use instead, how to make the switch, and who can help you navigate the transition to ensure mission success.
Think of a pyrovalve like a fuse: simple in design and trusted in a variety of industries.
But that simplicity comes at a cost. Pyrovalves are one-time-use devices that rely on explosives, making them tricky to integrate and test. Despite their reputation for reliability, pyrovalves often introduce a range of engineering and operational challenges.
Here are some of the most common hurdles they present:
Pyrovalves have been a reliable choice for years. As engineering demands evolve and systems become more complex, there’s increasing interest in solutions that offer enhanced safety, adaptability, and reduced risk.
Modern valve technologies are designed to support these goals, providing new opportunities for performance and innovation.
Passive and non-passive valve solutions deliver enhanced operational performance, addressing key limitations of legacy pyrovalve designs. Together, these options expand design flexibility and improve system performance within a variety of critical defense applications.
Designed to meet long-duration storage and harsh environmental requirements, passive valves offer a compliant, low-risk alternative to pyrotechnic systems. They require no electrical input for actuation, instead relying on environmental triggers like pressure, temperature, or flow. Common examples of passive solutions include burst discs, thermal relief valves, and pressure-activated valves like check valves and pressure relief valves that are suitable for both hydraulic and pneumatic applications.
Passive valves are a dependable solution for missile systems, particularly in environments where submerged components must remain operational after long periods of storage. Their ability to maintain exceptionally tight leakage control and deliver flawless performance upon activation passive valves ideal for high stakes, mission-critical applications.
One good example of how passive valves can be used to replace pyrovalves is in small turbine-powered missiles. These systems typically rely on pyrovalves to keep the fuel tank sealed until the engine is called for operation. The pyrovalve sits at the fuel pump outlet, just before the turbojet engine, and stays shut during long-term storage (sometimes in excess of 20 years). Instead of using electronics or explosives, a passive valve can do the same job by simply using pressure from the pump to open up when needed. It’s a cleaner, simpler setup – and since there’s no electrical or pyrotechnic components involved, you don’t have to worry about EMI.
Our passive latching valves feature very tight leakage performance and an optional latching mechanism. Once triggered, the valve remains open until manually reset, which can be easily achieved using a gauge pin to override the latch. Unlike pyrovalves, Lee passive valves can be tested repeatedly before deployment, offering significant advantages in reliability and maintainability.
Non-passive valves require electrical input and are ideal when more precise control is needed. These valves operate using pressure supplied by a charged bottle, compressor, or pump and are commonly found in systems where accuracy and responsiveness are critical.
Typical examples include:
Non-passive valves are frequently used in high pressure munition launchers, providing dependable control over gas discharge. Their value is especially evident in aerospace and defense systems, where performance, reliability, and control are paramount. These environments often demand features such as zero leakage, fast response times, and low power consumption.
We offer a range of non-passive valve solutions, including solenoid valves engineered for both pneumatic and hydraulic applications. Lee latching solenoid valves contain magnets that hold the solenoid open after a single pulse and remain latched open throughout the mission (eliminating the need for continuous power draw).
An early application for our solenoids was replacing pyrovalves in missile launcher systems (also known as bomb or ejector racks). The zero-leak design and fast response time of our solenoid valve made it possible to precisely control missile release using high pressure nitrogen. Since then, Lee solenoids valves have been adopted into a wide range of tube, rotary, and rail launcher applications across land, air, and sea platforms. Today, they’re used to reliably launch everything from missiles to sonobuoys, torpedoes, drones, and decoys, supporting defense systems around the world.
The right choice depends on your specific application and mission needs. Focus on lifecycle costs and maintainability. Passive systems are simple, reliable, and built to handle tough environments without needing power. Non-passive systems give you more control and flexibility, but they do require electrical input and a bit more infrastructure.
When you’re weighing options to replace your pyrovalve, make sure to consider:
Now that we’ve looked at how passive and non-passive valves compare, it’s worth seeing how both stack up against traditional pyrovalves. The chart below breaks down key factors like reliability, activation speed, testing options, and qualification requirements to help inform your choice.
| Metric | Pyrovalve | Lee Passive and Non-Passive Valves |
| Reliability | High (but single-use) | High (with reusability and diagnostics) |
| Activation speed | Milliseconds | Comparable for electromechanical valves |
| Shock/debris | High | Low to none |
| Testing | Destructive, single-use, no ATP | Non-destructive, repeatable, ATP |
| Qualification | More challenging to qualify | Easier to qualify |
| Cost | High carrying costs. More expensive over time, since each valve is used only once. | Low carrying costs. More cost-effective in the long run because each valve can be re-used. |
A complete drop-in replacement for a pyrovalve is rarely possible. In most cases, only a partial redesign may be required (especially when transitioning to non-passive systems that involve electrical control or feedback). Success depends on how closely the alternative solution matches the pyrovalve’s form factor and function. A full redesign may be necessary if the system architecture must evolve to support new safety, control, or redundancy features.
A smart strategy to prove out the change is to test components individually before fully integrating them into your system. Look for fluid control supplier partners who can support you throughout the transition process, provide replacement analysis, or match standard pyrovalve fitting connections and fluidic interfaces.
While our solutions differ in envelope and form factor, they’re often smaller than pyrovalves. They can be configured with similar interface connections to pyrovalves, including AS fitting ends or tube stub connections for ease of integration. A mechanical latching valve can be configured into a cartridge insert installed directly into manifolds to offer additional savings on space and weight. We also provide modeling and diagnostic support — helping to optimize performance and streamline the transition. Risk is minimal because the internal details of each valve derive from our field-proven, time-tested COTS components.
Replacing your pyrovalve isn’t just about swapping components — it’s about partnering with experts who understand the complexities of defense systems and the critical role fluid control plays in mission success.
Are you confident your current fluid control supplier can meet the evolving demands of your application?
The Lee Company has been a trusted supplier for the defense industry for decades, with over 20 years of experience replacing pyrovalves in high stakes applications — from high pressure munition launchers and small turbojet engine fuel systems to bleed air systems for fuel tank pressurization and inerting. Our deep understanding of qualification standards and program success requirements ensures our solutions meet the rigorous demands of modern defense platforms.
Unlike pyrovalves, Lee components:
Our components deliver critical space and weight savings while reducing risk and optimizing performance. With tens of thousands of parts in service, we’ve helped countless customers make the switch with our passive and non-passive valves.
Are you ready to replace your pyrovalve? Contact a Lee Sales Engineer today to explore how our proven solutions can help improve the reliability, testability, and performance of your system.
Always verify flow calculations by experiment.
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