Flow Control, Flow Control December 2017

application As depicted in Figure 3 singleand multiseal systems can be arranged Seeding In a seeding application the unitized piston provided a customer with two upgrade opportunities 1 reduction of the overall length of the piston to gain cylinder stroke length and 2 ability to use a less complicated and less expensive piston seal to pass internal ports in the cylinder A piston design was proposed that reduced overall length while maintaining the existing bearing protection The pistons tight fit to the cylinder bore protected the seal from contamination and extrusion when crossing internal ports Finally the pistons unique design features helped control fluid flow into the internal ports a problem the customer was unable to address until the unitized piston became an option Ultra high speeds A customer application required a sealing process that would be used in a repeatable fashion at ultrahigh speeds 20 feet second Using a custom sealing system and an extremely tight fit to the cylinder bore the required speed and durability were achieved The tight fitting bore combined with the design teams system approach to addressing the issue allowed the seals to survive at high speeds and multiple uses with no visible damage or performance depletion Repeatability was especially important because the equipment was used in an environment in which repair and rebuilding were not feasible FC Table 1 Standard metric and inch sizes available for a unitized piston Authors note This article describes the T720 unitized piston which was introduced to the market by Hallite Examples of how the product is being used by Hallite customers are featured Ryan Webster is director of engineering for Hallite where he manages the companys seal design and development activities His previous positions at Hallite include engineering group leader lead engineer for OEM customers and senior applications engineer Webster is a graduate of Lawrence Technological University Contact him at rwebster@ hallite us www flowcontrolnetwork com December 2017 29