Follow The Lee Company
Hand bleeding removes trapped air from hydraulic systems to restore performance. The drilled hole method utilizes a tiny opening in the housing to vent air, but too large of a hole can allow constant fluid loss. To solve this, The Lee Company developed an air bleed orifice with a precision flow and safety screen that vents air to the sump while restricting liquid flow, minimizing system losses. Remove air from your hydraulic system.
Pounds per square inch (psi) is a unit used to measure pressure. It can describe either absolute or gauge pressure, depending on the context. Read more about psi.
The resistance of liquid to flow is measured in Lohms. Lohms is a unit of measure which factors in pressure, flow rate, density, and viscosity to simplify hydraulic system design. Learn more about Lohm Laws.
There are four primary tests for pneumatic leakage: bubble test, pressure decay test, mass flow test, and helium leak test. To find a test that aligns with your specific needs, begin by defining the leakage requirements of your component or system. Understanding the best practices associated with common leakage testing methods will help further guide your selection. Learn what test works best for your pneumatic application.
Lohms provide a consistent way to measure flow resistance for a single orifice in both hydraulic and pneumatic systems. For more complex components with multiple flow paths or restrictions, the Lohm calculation remains a good estimate of performance but often correction factors are needed for exact results. Using components tested on the same fluid type as the system, liquid or gas, takes much of the error out of the correlation. Learn more about Lohm laws working with liquids.
A solenoid valve controls the flow of liquid or gas using an electric coil (the solenoid) and a valve. When voltage is applied, the coil generates a magnetic field that moves a ferromagnetic plunger, which shifts internal valve components to regulate flow, direction, or pressure. When the coil is de-energized, the magnetic field collapses and the valve returns to its original state. Find how solenoid valves can help your fluid application.
The Lee Company qualifies its standard designs with a rigorous series of tests to meet the needs of the Aerospace industry. The tests are guided by RTCA/DO-160G and many Military Standards including MIL-S-4040 G, MIL-STD-202 H, MIL-STD-810 H, and MIL-STD-461G. With space being our fastest growing market, on newer designs we are including tests to show they meet the requirements of the leading launch vehicles Payload User Guides. The qualification test reports for standards are available upon request. Explore our quality policies.
A solenoid valve can malfunction or fail due to improper installation, over-voltage, over-temperature, contamination, pressure fluctuations, or insufficient pressure or flow conditions — making system design critical. Discover common solenoid valve failures.
A miniature piloting solenoid valve is a compact component that utilizes an electrical signal to allow pressure to actuate a much larger mechanical valve upon command. Find your miniature piloting solenoid valve.
Medical devices use a variety of different miniature solenoid valves. Directional control valves manage flow direction of liquids or gases within a fluid system. Non-inert valves, often called control or pneumatic solenoid valves, typically include metal components in the fluid path. They are cost-effective and well-suited for directing air or mild gases. Dispensing valves are optimized for precision dispensing applications. Find a solenoid valve for your medical application.
Current flows through the coil of a solenoid-operated electrical switch when voltage is applied to the coil. An electromagnetic field forms as soon as the coil is energized. This actuates the plunger and enables electrical control of a mechanical switch. Discover more about solenoid valves and how they work.
We sell a variety of solenoid valves, with differing electrical connections depending on the product line and market they serve. Many of our health and science solenoid valves are sold with pin terminations, lead wires, or pin socket/locking end caps. We also sell accessories to ease prototyping, including standard lead wire connectors (which we do not manufacture ourselves). These off-the-shelf connectors are widely available from a variety of suppliers. Find a solenoid valve that fits your health and science application.
A pneumatic pressure relief valve protects systems from sudden pressure spikes by opening to release gas when the pressure exceeds a set point. When pressure returns to a specific set point, the relief valve closes. While metal to metal seals often work in hydraulic systems, these typically have elastomeric or polymeric seals for better performance with gas as medium. Learn more about pneumatic pressure relief valves for hydraulic applications.
A pressure relief valve works by opening at a set pressure allowing fluid to escape, relieving pressure, and preventing system damage. It reseats once pressure drops to a safe level. Discover critical characteristics about pressure relief valves.
A check valve is used to let gas or liquid flow in one direction while blocking flow in the opposite, protecting systems from backflow and maintaining efficient operation. Explore our check valves for space applications.
Yes, we offer check valves, pressure relief valves, single-orifice restrictors and safety screen filters for installation into plastic. We also offer them installed into various plastic fittings, including barb-to-barb unions, male-to-female luer adapters, and luer tee fittings. Find your check valve.
In a hydraulic schematic, a check valve is represented by a circle (the ball) resting in a V shape (the seat). Free flow is from the seat side to the ball side. Learn more about check valves for hydraulic applications.
We offer valves that can open at 300 mm Hg across a range of flow rates, materials, and installation styles. To recommend the best fit, we’ll need your target flow rate, installation material, and orientation. These details help us identify the most compact and compatible option for your application. Explore our check valves for your medical application.
A flow restrictor (or flow limiter) is any device that restricts or limits the flow of a fluid, generally a liquid or a gas. When fluid passes through an orifice, its pressure increases upstream of the orifice. As fluid is forced to converge and pass through the orifice, the velocity increases and the fluid pressure decreases. Discover our guide to selecting a flow restrictor.
For reliable installation, wax is applied to the pins of most Lee restrictors. Within our Gas Rated series, which includes our Gas Rated Visco Jet Multi-Orifice and Gas Rated Lee Jet Single-Orifice Restrictor, the pins are designed to be installed without the assistance of wax. For these restrictors, the pins are shipped wax-free. Check out our gas rated restrictors.
The flow fuse is designed to function as a normally open check valve. The pressure differential across the valve increases as the flow rate increases. Once this differential exceeds a specified value, a poppet shuts against the valve seat to stop the flow. Once the pressure differential decreases below the specified valve, the valve will reopen. Explore our shutoff valves.
We offer a range of 3/2-way solenoid valves, including latching options ideal for battery-powered devices. While our catalog may not list a standard valve with 25 LPM flow, we can customize a solution or combine multiple valves into a compact manifold with a single part number. Let us know your flow, pressure, and power needs to explore the best fit. Explore our selection of solenoid valves.
A miniature positive displacement pump is a compact, lightweight pump that uses mechanical parts like pistons, gears, or lobes to displace a known, fixed volume of fluid for each cycle or revolution. This results in a consistent flow rate that is relatively unaffected by system pressure changes. Find the miniature positive displacement pump that fits your application.
A shuttle valve connects one of two inputs to an output port, enabling control line selection, redundancy, or isolation. Valve types vary depending on application. The Lee Company offers spring-biased, detented, selective, inverse, and zero-leak shuttle valves, each designed for unique performance needs across a variety of hydraulic systems. Discover our zero-leak shuttle valves.
The Lee Company’s NACE-compliant high pressure check valves use a metal-to-metal seals and are hydraulically tested. Some leakage may occur when used with gas, and better than a specified leak rate cannot be guaranteed. Our Extreme Environment series check valves are also NACE-compliant and feature a polymeric seat. They offer a leak rate of zero nitrogen bubbles during a one-minute test at pressures ranging from 500 to 15,000 psid. Learn more about NACE compliant check valves.
A pressure relief valve is a direct-acting device, which means pressure acts directly upon the internal components of the valve. When pressure increases beyond the valve’s specified limit, the valve is forced open, allowing fluid to vent out of the pressurized area to another section of the system or to atmosphere. By allowing fluid to vent, the pressure relief valve prevents pressure from building up further which could damage or break other components within the system. Find your pressure relief valve.
Yes, our check valves can be used in high humidity environments. Depending on operating conditions, alternate materials such as a ceramic ball or 316L stainless steel should be used for enhanced corrosion resistance. Valves with elastomeric seats or seals can swell in humid environments, so it is important to review these application-specific details with a Lee Sales Engineer to address compatibility concerns. Find what check valve works for you.
The Lee Company does not manufacture adjustable relief valves. All of our components have spring pre-sets, eliminating time and energy needing to complete adjustments in-house. We do offer a variety of pressure relief valves with varying standard cracking pressures to fit your application needs. We can also offer custom cracking pressures for your specific application needs that are in between our standard cracking pressure range. The cracking pressure range of our pressure relief valves, without factoring in other performance requirements, go up to 4,000 psi. Find which pressure relief valve works for your application.
Yes, we offer check valves, pressure relief valves, single-orifice restrictors and safety screen filters for installation into plastic. We also offer these components installed into various plastic fittings, including barb-to-barb unions, male to female Luer adapters, and Luer Tee fittings. Find which check valve solution works best for your application.
Yes, we offer a wide range of pumps and valves designed to build fluid-handling systems. These components are suitable for moving fluids in well plates and other microfluidic applications and can accommodate volumes from nanoliters to milliliters. Find a pump that works best for your diagnostic application.
Although The Lee Company does not typically provide build-to-print services, we can supply custom components that often serve as suitable replacements for existing parts. We offer a complimentary initial evaluation and are available for on-site or virtual meetings to review your application and requirements. Check out our pumps.
Press-in relief valves are designed for plastics with high elongation, such as polypropylene or nylon. Rigid plastics like acrylic and polycarbonate may crack under installation stress. For these materials, parts should be heat-flowed into the hole or hole tolerances adjusted to reduce stress. We recommend providing hole size, material properties, and performance needs (e.g., flow rate, media, and temperature) so we can confirm suitability or suggest alternatives. Explore our press-in relief valve catalogue.
We offer a wide selection of components. While an exact one-to-one replacement for every part number may not always be available, we can often provide a close alternative or even customize a solution to meet your needs. To ensure you receive the best possible match, we recommend consulting with one of our sales engineers. They’ll review your specifications and guide you toward the most suitable option. Connect with one of our sales engineers.
The Lee Company is fully registered and can support International Traffic in Arms (ITAR) applications. Our aluminum plugs are generally not subject to ITAR unless specifically modified. We comply with all required Defense Federal Acquisition Regular Supplement (DFARS) regulations for subcontractors of commercial items. View our ITAR Registration Letter.
Yes, we can customize pressure relief valves for cracking pressures below 20 psi by modifying our standard designs. Nearly half of all projects we talk on require unique solutions, and we regularly tailor components to meet specific system requirements. View our portfolio of pressure relief valves for hydraulic applications.
Yes, we offer a pneumatically‑operated solenoid valve that can be customized for hydrogen applications. Lee plugs are available in standard sizes made from 316 stainless steel, generally considered acceptable for use with hydrogen. Our other catalog products can also be customized for use in hydrogen systems. View solenoid valve options for hydrogen applications.
Yes, we offer dispensing valves that can precisely control the injection of gas or liquid into various media. Contact a Lee Sales Engineer to discuss your specific application needs. View our dispensing valves.
Yes, we offer several solenoid valves optimized for either minimal dead volume (3-way valves) or zero dead volume (2-way valves). Contact a Lee Sales Engineer to discuss your specific application needs. Find the solenoid valve that works for your application.
Standard temperature ranges vary across product lines. For more information, please reference the product information tabs for our Xover® 2- & 3-Way Isolation Solenoid Valve, LFN Series 2-way Isolation Solenoid Valve, LFR Series 3-Way Isolation Solenoid Valve, LFV Series 2-Way Isolation Solenoid Valve, and LSP Series 2-Way Isolation Solenoid Valve. You can also explore our Technical Fluid Control Handbook for Health and Science Applications or contact a Lee Sales Engineer for personalized assistance.
Yes. The Lee Company offers miniature solenoid valves specifically engineered for precision fluid control in demanding environments, including low Earth orbit (LEO) and vacuum chambers. These valves provide accurate, repeatable metering of DI water and other fluids even under extreme conditions. Discover the right solenoid valve for your space application.
While The Lee Company does not specifically offer a temperature fusible link valve, we do manufacture flow-triggered and pilot-to-close shut off valves and pressure/thermal protection components. Each component is qualified for demanding aerospace environments and available in a miniature, lightweight format. Discover our portfolio of shutoff valves.
Yes, we offer compact, highly reliable pressure relief valves that can be integrated into industrial lubrication systems to enable controlled grease egress during servicing. Our extensive portfolio includes multiple configurations optimized for installation into metal housings — delivering low cracking pressures, fast opening, and stable flow. They are ideal for tightly sealed bearings and service ports. Find which pressure relief valve works best for your industrial application.
Yes, we offer compact thermal relief valves and low pressure relief solutions engineered for thermal management systems like EV battery coolant loops. Designed for installation into metal or plastic housings, these valves safely relieve and vent excess pressure caused by reactions or temperature swings – making them suitable for systems that vent to atmosphere or to the sump. Find which pressure relief valve works for you.
Yes, we offer valves designed so that the entire wetted flow path is a single tube. These internal pinch-tube valves are ideal for handling liquids containing soft particles, beads, cells, or other fragile biological materials and offer smooth, low-shear flow and zero dead volume. Their easily flushable fluid path supports laminar flow and minimizes unwanted mixing, making them well‑suited for flow cytometry, gene sequencing, spatial biology, microbioreactors, and analytical chemistry applications. Check out our Xover® 2- & 3-Way Isolation Solenoid Valve. Check out our LSP Series 2-Way Isolation Solenoid Valve.
Yes, we offer compact, 3/2-way, low‑power solenoid valves suitable for medical and life‑science devices, with flow capabilities approaching 25 L/min. Our HDI/LHD, LHL, and LHQ series of solenoid valves are engineered to be compact, reliable, and customizable for demanding medical applications where size, sound, and power consumption are critical.
Yes, we offer internal pinch-tube solenoid valve technology for use in medical and scientific instruments. The Xover® 2-& 3-Way Isolation Solenoid Valve is a pinch-tube-style valve engineered for chemically inert flow paths. It offers ultra low carryover volume, zero dead volume, and fast, reliable flow switching. Cross over to Xover solenoid valves.
The Lee Company offers a broad range of miniature, precision solenoid valves for medical devices, including control solenoid valves, dispensing solenoid valves, and isolation solenoid valves. Each is engineered to deliver reliable, long term performance within compact medical systems. Our control solenoid valves are available in 2-way and 3-way designs, with options such as magnetically latching models for ultra low power operation and quiet operation models ideal for bedside equipment. We also offer high speed dispensing valves for nanoliter-to-milliliter dosing and chemically-inert isolation valves, including the Xover® 2-& 3-Way Isolation Solenoid Valve. This valve delivers ultra low carryover and zero dead volume, making it an ideal choice for handling sensitive fluids. Explore our solenoid valves for medical applications.
Yes, we offer high quality pumps for medical applications, including miniature piezoelectric micropumps and fixed or variable volume positive displacement pumps engineered for precise, reliable control of small fluid and gas volumes. Each pump is 100% tested to ensure long term performance across medical applications such as compression therapy, blood pressure monitoring, microfluidics, patient simulators, and diagnostic instruments. Among these solutions, the Disc Pump stands out as a revolutionary micropump that delivers silent, vibration-free operation and highly accurate, ultra smooth flow control in a lightweight design suitable for portable and wearable devices. Discover which pump suits your medical application.
The Lee Company offers poppet-style pressure relief valves, which use a direct-acting poppet design to deliver fast opening, stable flow, and quiet operation. These pressure relief valves are available in 5.5 mm and 8 mm diameters with all stainless-steel construction. Each is 100% functionally tested to ensure performance. We also offer solenoid-actuated poppet-style control valves for use in a wide range of health and science applications. Our HDI® platform of miniature, direct-acting control solenoid valves are used to direct the flow of gases and mild liquids. Their low power, low leakage, and long cycle life provide high value at an economical price.
The Lee Company offers miniature pressure‑relief valves in highly compact 5.5 mm and 8 mm designs. These valves are engineered to open at precisely controlled low pressures and deliver stable, repeatable performance – making them ideal for medical systems that require dependable pressure control. Explore our pressure relief valves for medical applications.
The Lee Company offers a PRI®/Chek valve which combines a pressure relief valve and a check valve into one compact insert, preventing backflow while protecting systems from overpressure spikes. These are used in high pressure systems, allowing free flow in one direction but checking reverse flow, with options for integrated screens and various cracking pressures.
The Lee Company offers both safety pressure relief valves and upstream pressure regulating valves with cracking pressures in the 200-250 psig range. The compact 375 Momentum PRI® pressure relief valve has a .375″ diameter and a full open Lohm rate of 100 Lohms, allowing it to flow 3.4 GPM at 250 psid.
The Lee Company’s Solenoid Operated Pneumatic Isolation Valve is built to maintain a tight seal across a wide operating pressure range of 0–6500 psid. Backpressure limits depend on your application, but the valve’s full operating pressure rating applies in both directions, enabling it to tolerate substantial reverse differential pressure when closed. For systems that regularly apply backpressure from the control side, we recommend reviewing your exact operating conditions with a Lee Sales Engineer to ensure proper valve selection and long term performance. Connect with one of our experts.
Yes, we offer solenoid valves that are engineered for compatibility with specialized hydraulic fluids, including phosphate-ester-based fluids such as Skydrol®. Standard configurations are available that are functionally tested using Skydrol. Explore our solenoid valves for hydraulic applications.
Note: Skydrol® is a registered trademark of Solutia Inc.
Yes, we manufacture precision fluid control components widely used in defense and aerospace applications. Our products support mission critical systems including flight controls, utility actuation, landing gear, brakes, missile seekers, and munition deployment. Engineered for reliable performance, Lee products are field‑proven across aerospace and defense platforms worldwide. Discover more about Aerospace & Defense markets we serve.
Yes, The Lee Company is a leading innovator in miniature fluid control components for demanding oil and gas applications. Our sealing technologies are designed to protect critical systems under extreme conditions, helping customers maintain safety, performance, and uptime. We support the oil and gas sector with proven, field-tested components trusted in mission-critical operations across the globe. Explore our oil & gas fluid control component solutions.
Aluminum versions of the Lee Plug® are not recommended for use above 275°F because higher temperatures can affect material strength and long‑term sealing performance. The Lee Controlled Expansion Principle relies on the plug and housing maintaining proper mechanical integrity. Excessive heat may reduce aluminum’s yield strength and compromise retention or leak‑tightness. For applications requiring higher temperatures, we offer the Lee Plug in alternative materials such as stainless steel, Monel, MP35N, and titanium to ensure reliable performance across more demanding thermal environments. Learn more about The Principle of Lee Plug Performance.
The Lee Company offers a variety of miniature shut‑off valves – including bypass valves and flow fuses – engineered for aircraft fuel and hydraulic systems. These valves offer precise, reliable flow shutoff, lightweight construction, and compact designs ideal for aerospace environments. Bypass valves are hydraulically piloted to close when system pressure is lost. Flow fuses automatically shut off flow when it exceeds a specified limit and can also vent trapped air or vapor in fuel systems. These solutions support critical fuel distribution and shutdown safety across modern aerospace platforms. Explore which shut-off valves work best for your aerospace and defense application.
Always verify flow calculations by experiment.
*There are many parameters to consider when determining V-Factor. Click here for more information.
