The Lee Company has produced expansion plugs since 1948. Initially designed for aircraft manifolds, our plugs have since been utilized for hydraulic and pneumatic manifolds in dozens of other industries, including power generation. The machines that create power for entire states and cities have unique requirements, and any failures can plunge the grid into darkness. That’s why high-quality components from The Lee Company are so important.
Lee Plugs are a unique design. Unlike other designs that rely on threads, O-rings, or sealants, the Lee Plug forms a leak-tight metal-to-metal seal using the principle of controlled expansion. Each new shipment of plugs is manufactured under a benchmark quality management system and has exacting requirements for acceptance. As a result, we guarantee the best designs and the best quality products to serve an extremely demanding industry.
Our standard product offering usually contains a plug in the size and proof pressure that a customer needs. This includes evolved configurations of our original expansion plug with different material, installation, and retention options. With that said, we’re more than happy to create new designs on request. Each of our customers is unique – and they often need unique plugs. Over half of the work we perform at The Lee Company is customized to meet the needs of a specific application. So whether your solution is off-the-shelf or one-of-a-kind, you can rest assured knowing that Lee products always adhere to exacting standards for quality and performance.
The founding, flagship product from The Lee Company. It works like this: the cylindrical plug body contains a tapered hole partway through. First, the body is inserted into a properly reamed hole. Then a tapered pin is inserted into the plug itself, causing the plug to expand in a controlled manner. Lands and grooves on the side of the plug then bite into the sides of the hole, creating multiple metal-to-metal seals. See Installation Process Specification 203 (which applies to all Lee expansion plugs) for more information.
Lee Plugs are manufactured to exacting tolerances. Every process is precisely controlled. Each lot of pins and plugs undergoes rigorous inspection and acceptance testing to ensure peak performance where any failure could be catastrophic.
Standard Lee Plugs are available in multiple grades of aluminum, stainless steel, and Monel, plus titanium and MP35N. They can be purchased in diameters from 0.093 to 0.656 of an inch or metric sizes from 2.5 to 8.0 mm.
Lee R.F.O. Plugs are designed to seal holes in thin walls or fragile materials. Designed to be easily removable, these plugs do not require a support shoulder and the installation system ensures that no downward pressure is applied to the product.
Lee R.F.O. Plugs are available in aluminum and can be found in standard diameters ranging from 0.156 to 0.875 of an inch.
The Lee QIP was developed to provide a more straightforward method of handling and installing the smallest plug sizes. This is accomplished by pre-installing the pin into the plug. This pre-assembled component adapts more easily to automated installation. Despite their smaller size, these plugs experience no loss of strength, with proof pressures up to 12,000 psi.
The Lee QIP is available in aluminum and is offered in four standard sizes: 0.093, 0.125, 0.156, and 0.187 inch diameters.
Unlike other plugs in our product family, A.F.O. Plugs are both removable and reusable due to their threaded design, allowing technicians easy access to sealed passageways. Despite this, the A.F.O. Plug still seals up to 56,000 psi. Each plug features a floating seal that self-aligns, allowing for threaded holes that aren’t concentric with the through-hole. Lastly, the A.F.O. designation means no radial force is applied during installation, making this component suitable for thinner-walled housings. See Installation Process Specification P1013 (which applies to all A.F.O. Plugs) for more information.
A.F.O. Plugs are made from stainless steel and are available in standard diameters from 0.190 to 0.625 of an inch.
The Dual Sealing A.F.O. Plug comes with all the strength and ease of use offered by our regular A.F.O. Plugs, but with added safety features for use in hydraulic systems. The incorporation of an O-ring allows users to vent gas out of a side port or safely release trapped high-pressure gas. This enables the Dual Sealing A.F.O. Plug to be used for “fill and drain” applications. In addition, a newer higher pressure version of this product is available with backup rings rated to seal up to 15,000 psi when partially open.
The Dual Sealing A.F.O. Plug is available in stainless steel and can be purchased in diameters of 0.3125, 0.375, 0.500, and 0.750 of an inch.
Lee Cross Port Plugs are a plugging solution specifically engineered to seal cross port passageways. This configuration is a variant of the original Lee Plug® that set industry standards over 65 years ago. A smooth wall design combined with the field-proven controlled expansion principle creates a permanent, leak-proof seal without the need for O-rings or sealants. Installation is simple and reliable, and the plug requires no maintenance thereafter.
Lee Cross Port Plugs are ideal for isolating sections of a fluidic manifold. They are also used to plug deep passageways that are difficult to access with conventional sealing methods.
Lee Cross Port Plugs are constructed from 6Al-4V Titanium. They have been qualified for proof pressures over 20,000 psi and at temperatures up to 400°F. Configurations are available in 0.250, 0.281, and 0.343 inch diameters.
Partner with The Lee Company and get much more than just a supplier of top-quality fluid control products. Our reliable technical support team is available every step of the way to help you find solutions, maximize productivity, and drive efficiency across your operations. Check out these resources specific to the power generation industry.