Rolling diaphragm delights Wichita

A custom engineered rolling diaphragm is helping Wichita Clutch to achieve enhanced performance in a recently developed actuator option for its ModEvo tension control brake.

A custom engineered rolling diaphragm, designed and manufactured by the Bedford based seals specialist Ceetak, is helping Wichita Clutch to achieve enhanced performance in a recently developed actuator option for its ModEvo tension control brake.

The Ceetak rolling diaphragm is manufactured from a flourosilicone material, with Nomex reinforcement for additional strength and optimal temperature resistance.

It ensures that Wichita can achieve high torque ratings with its ModEvo actuator option, that would not be possible with more traditional rolling-diaphragm designs.

Wichita manufactures a wide range of pneumatic and hydraulic clutches, brakes, tension control systems and ancillary equipment for a variety of industries.

The ModEvo tension control brake is a modular unit, designed specifically for print and converting unwind tension applications.

Three actuator options are available with the ModEvo, covering clamping forces of 100, 60% or 25% - featuring Ceetak's rolling element diaphragm.

The ModEvo tension control brake was developed by Wichita in direct response to market requirements for a system that could provide the appropriate braking force, but also had the sensitivity to cope with paper or film web changes of varying thickness.

Wichita's more conventional braking systems, which use pistons to provide the braking force, were less able to offer the required sensitivity so Ian Hakon, Engineering Manager at Wichita, decided to incorporate rolling diaphragms into the actuator option on the modular ModEvo.

Wichita quickly dismissed the conventional "top hat" rolling diaphragm design, as the size necessary to meet performance requirements was too large for the desired application envelope.

In essence, Wichita required a rolling diaphragm seal that was compact enough to fit within the actuator design, could withstand temperatures up to 200øC, provided a wide ranging stroke capability and could respond quickly and accurately to pressure changes despite demanding operating temperatures.

Ceetak was able to provide a solution that met all the design parameters set by Wichita, including size - through the incorporation of a special internal bead that optimises space for increased stroke capacity.

"We had looked at other rolling diaphragm suppliers, but they were only able to offer us standard products that didn't meet our high performance requirements", explains Ian Hakon.

"Ceetak was able to offer us an effective solution with its custom engineering service, working closely with us to develop a diaphragm that met our exacting requirements".

"As a result of this added value service and the excellent performance of the Ceetak diaphragm in the field, we are now looking at incorporating similar Ceetak diaphragms into other pneumatic products in our range where sensitivity is also required".

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