Filter candle is the candle shape replaceable filter element used in candle filter. Filter candle is often long and thin, with connecter to ease the installation.

Candle filter

Candle Filter scheme from Steri

Candle filter is a type of pressure filter operating in certain process circles, which may include precoating, filtration, backwash and cake discharge. The pressure vessel, inlet & outlet, filter candles and discharge mechanism are the main components of the candle filter.

The fluid ( liquid or gas) are often filled in from top of the vessel, and the filtrate outgoing from the top, as well. The bottom of the candle filter can be silo / cone shape or flat depending on the discharge phase and function.

Filter candle

Filter candle is the main filtration element in the candle filter. There are various filter candle types due to the design and application of the candle filter.

Sintered wire mesh filter candle in a wooden box

Sintered wire mesh filter candle

Sintered wire mesh filter candle is well performed in liquid filtration application with property of high permeability and high flow rate. The multi-layer structure gives the sintered mesh filter candle enough strength while reducing weight than other solutions. The layers can be chosen and aligned with various combination, thus provide versatile solutions for a wide range of applications. The filter rating of the sintered mesh filter candle is often in micron range, limited by rating of the wire cloth itself.

Sintered metal fiber filter candle with perforated metal tube and thread connector

Sintered metal fiber filter candle

Sintered metal fiber filter candle can be whether cylindrical or pleated type. Cylindrical type metal fiber filter is often used in gas filtration. It outperforms the filter bags as it cleanable, reusable and high-temperature resistant.

Pleated type metal fiber filter candle is widely used in high viscosity fluid filtration, like polymer melt, plastic recycling. The metal fiber filter candle have large filtration area and can be cleaned by backwashing and outline cleaning methods like chemical cleaning and combustion decomposing.  The filter candle is often reinforced with perforated metal tube inside and outside to ensure higher pressure resistance.

Pleated wire mesh filter candle

Pleated wire mesh filter candle

Pleated wire mesh filter candle has more filtration area than cylindrical type filter. It provides larger dirty holding capability and ensures high flow rate with longer washing interval. Wire mesh type, layer, structure can be customized to provide various micron rating and pressure handling options. Pleated mesh filter candle can be used in steam and other high temperature gas filtration.

Wedge wire filter candle

Wedge wire filter candle

Wedge wire filter candle has simple structure, high flow rate and non-clogging property. Wedge wire filter candle can be used in high flow rate and less contaminated filtration application, such as water filtration. Media filter is also an popular usage of the wedge wire filter. The wedge wire filter candle is immersed into the filter media, such as diatomaceous earth / kieselguhr, sand and gravel. The wedge wire stops the filter media while lets the filtrate passing through.

Sintered metal powder filter candle

Sintered metal powder filter candle

The sintered metal powder filter candle is robust in structure and can withstand higher temperature and pressure. Due to porous structure and filter cake effect, it can constrain solid particles much smaller than 1 micron in gas filtration application. If made by special alloys like Inconel, Titanium, Hastelloy,etc, the sintered metal filter can work in extreme high temperature and severe corrosive condition.

Perforated metal synthetic filter candle support

Synthetic fiber filter candle

This type is often a filter bag/ sock wrapping on a metal perforated tube filter candle inner support core. The cake accumulated on the filter media can be released by pulse or shocking, as there is flexibility on the filter bag.