Hallite® unitized pistons

Hallite® unitized pistons

The Hallite 720 is a completely self-contained piston, bearing, and seal-in-one assembly that solves difficult assembly problems and can be a cost-effective alternative to the traditional piston assembly which has a separately fitted seal and bearing(s). The Hallite 720 improves stability and has smaller extrusion gaps that extend the life of the piston seal. Moulding the bearing material over the outer diameter gives an extremely tight fit between the piston and the cylinder bore. The piston diameter is tightly controlled which reduces the tolerance build up and results in increased performance. The Hallite 720 unitized piston is constructed using four components:

• High strength steel body

• Non-metallic bearing

• Rubber energiser

• Filled PTFE seal ring for inch sizes

• Polyurethane seal ring for metric sizes

The steel piston body is machined to exact dimensions. The non-metallic bearing material is moulded to the piston using a special proprietary process. It is then machined to the final precise outer diameter dimension to suit the cylinder bore and the seal is fitted. It is supplied ready to be attached to the piston rod for use in a cylinder. In many cases the Hallite 720 is also supplied with an internal static sealing O-ring to provide a positive seal between the piston and the rod. Those marked with an asterisk in the part number range on the following pages do not have this internal seal. The materials used in the standard unitised piston are selected to handle a broad range of application parameters.

The piston housing is machined to exact dimensions. The non-metallic bearing is cast onto the piston using a special process. It is then machined to the final accurate OD size and the seal is installed. It is delivered ready to use in the cylinder.

Hallite's exclusive Type 720 Unitised Piston is produced today in a wide range of sizes, bearing and seal materials and is available from stock in numerous standard metric and inch sizes.