The breakthrough in the effective and economic development ofvane seals, for Busak+Shamban, came about through a pioneeringdevelopment of an innovative method for stamping sintered Turcon®PTFE plates. This process replaced high-cost milling, previouslyrequired to achieve the rectangular seals with razor-sharp edges,essential to achieving sealing integrity within rotary actuatorapplications.
Rotary vane actuators have an increasing diversity of use withincontemporary engineering design including the control of aircraftwings flaps, anti-roll suspension systems on high-performancepremium cars, and now, within a new generation of machine tools,such as multi-directional tube bending equipment. (See picture)
The majority of actuators are designed with one or two vanes butversions are available with three or more vanes. In a two vanerotary actuator, the piston, which operates within linear hydrauliccylinders, is replaced by a rotor with two vanes attached. Whenfluid pressure is applied to two of the four working chambers, theactuator turns, necessitating perfect sealing to prevent leakageacross the chambers. This type of seal is called a 'vane seal'.
Effective sealing is a challenge, as the shape to be sealed isrectangular and the four corners of the rectangular seals must berazor-sharp. In the event of there not being a perfectly sealedsurface, sealing integrity may be compromised as liquid could leakfrom one working space to another. It was thought the onlyeffective method of producing these sharp edged rectangular sealswas through a high-cost milling process.
Stainless steel tube bending for marine and architecturalfittings, a typical new machine tool application using rotary vaneactuators with vane seals.
An alternative concept proposed to reduce production costs andincrease yield was to stamp sintered PTFE plates to the shape ofthe seal. Following attempts to achieve this by one of Europe’sleading stamping companies, Busak+Shamban turned to their ownproduction facility in Denmark, where vane seals with razor sharpedges were successfully produced using Busak+Shamban proprietaryTurcon® PTFE material. By utilising this high performance material,sealing integrity was ensured at both room temperature andextremes, ranging from –40°C to well above +100°C, and at pressureexceeding 150 bar.
This latest manufacturing advances are providing distinct costand performance benefits to customers and extending the potentialapplications for rotary vane actuators in many areas ofindustry.