Maintenance-free, self-aligning spherical bearings are used which require no lubrication. The bearings are mounted on glands which are packed with ceramic fibre and annular gaskets to create a labyrinth. This minimises process gas egress and helps to insulate the bearings from potentially high temperature process gases. Where chemically corrosive gases are involved additional shaft seals can be filled, beneath the bearings, in materials such as Viton or PTFE (whichever best suits the process gas constituents).
Shut-off dampers generally incorporate a single seal ring which consists of a solid steel ledge in its simplest form. More sophisticated seal options are available, where process conditions allow. These include rubber ‘P’-section or ceramic fibre ‘P’-section compression seals, stainless steel flexible seals and rubber wiper seals. For more information on seal options and seal selection criteria can be found here. Theoretically estimated sealing efficiencies typically range from 99% to 99.9% on CSA, depending the damper size and seal type.
For some shut-off damper applications, where the frequency of operation is low, manual operation is often the best option as it is the most cost-effective. If powered operation is necessary, pneumatic activation is usually the most cost effective. It also lends itself well to fail-safe operation on loss of either pneumatic air supply or loss of control signal. Where a pneumatic air supply is not available, we can fit electric actuators or hydraulic cylinders instead.
In the case of hydraulic actuation, the customer ordinarily provides the pressurised oil supply, but we are also able to quote for a hydraulic power pack to power one, or multiple dampers.
For more info on actuation options click here.
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