CANDLE Filter Design: Operate Without Moving Parts

Steri CANDLE Filters Have No Moving Parts
The Steri CANDLE filter design is meant to operate without any moving components. The few seals that are needed are static and not subject to wear. This increases the operational reliability and reduces maintenance requirements and costs dramatically. Due to its simplicity, the CANDLE filter serves a wide variety of applications.

Anatomy of a Steri CANDLE Filter
The CANDLE filter element is cylindrical in shape and can be installed in a single tube or arranged in a group inside of a larger vessel. In either case the individual CANDLE filter elements are connected to headers in a series and/or parallel arrangement. This arrangement is determined by Steri’s engineering team during the design phase based on the process results required. The headers are then connected to the main manifold though valves. Filtration and back-washing are controlled by these valves. Operation of the valves allows flow control in the CANDLE filter elements to optimize cake formation. Valve operation makes it possible for fine filtration and backwashing to be cycled from header to header.

Why CANDLE Filters?
Most filters rely, to varying extents, on the solids collected on the filter surface to achieve maximum effectiveness, essentially using the solids themselves to trap more incoming solids. But, as the cake builds on the filter surface, the distance that the fluid must travel through the cake increases which increases pressure and lowers the flow rate. In the CANDLE filter, solids are removed from the slurry as the fluid passes through the filter media from outside. So as the cake grows on the outside of the cylindrical CANDLE filter surface, the surface area also increases. This means that the cake thickness grows more slowly than it would on a flat-faced filter, and results in a more linear change in pressure and flow rate.