Puristusnuttia

Puristusnuttia is the Finnish term for the compression nut, a hexagonal fastener used in combination with a compression sleeve (olive) and a fitting body to form a sealed piping connection. It is a common component in plumbing, hydraulic, and gas systems where soldering or welding is undesirable or impractical.

Construction and function

A compression nut works with a ferrule and a pipe to create a seal. When the nut is tightened, it pulls the fitting body toward the ferrule, causing the ferrule to deform around the pipe and press it against the seating surface inside the fitting. This metal-to-metal contact provides both a grip and a leak-tight seal. The nut is designed for wrench use and is usually made of brass, steel, stainless steel, or plastic. Sizes and thread types vary, with metric and imperial standards (such as BSP or NPT) used depending on region and application.

Materials and compatibility

Common materials for puristusnuttia include brass and stainless steel, chosen for corrosion resistance and durability. The corresponding compression sleeve and fittings must be compatible in material to avoid galvanic corrosion. Puristusnuttia come in a range of sizes to fit various pipe diameters, from small residential lines to larger industrial systems. Proper matching of nut, ferrule, pipe, and fitting is essential for a reliable seal.

Installation considerations

During installation, the nut and ferrule are positioned over the pipe before insertion into the fitting. After the pipe is seated, the ferrule is pressed onto the pipe, and the nut is tightened to the recommended torque. Reusing ferrules or nuts is generally not advised, and overtightening can damage components or the pipe. Regular inspection for leaks helps ensure long-term performance.