The self cleaning viscous air filter or oil bath filters is particularly suitable in many industrial applications to filter large air volumes with high dust concentrations.

The advantages of viscous air filter are:
• Constant high cleaning efficiency and pressure drop
• Minimum maintenance
• Low working cost
• Easy installation

Construction
The automatic viscous air filter manufactured by Filtrotecnica Italiana is completely made of pressed and bent steel sheet. The component parts are electrowelded and painted. The totally metallic filtering media consists of special overlapping panels to form filtering curtain at front and rear of the filter. The panels are made of die – stamped carbon steel or corten steel and can be inserted in a single way (codeS) or double way (code D). The panels are suspended on two lateral heavy duty endless chains with specially designed links which permit both the panel assembling and the filtering wall rotation. In the upper part of the filter are located the mechanisms for the rotation of the whole filtering curtain. The movement is given by on electric gearmotor that is front mounted in order to permit the mechanical connection of several units and to make checking and service operations easier. In the lower part are located the sprockets for rotation of the filtering curtain besides the reservoir of the viscous filtering oil. If an external oil clarifier is required the reservoir is equipped with the necessary hydraulic fittings. Our technical office is able to dimension the system to solve the problem of your plant.

Principle of operation
The air filtration is achieved by the special louvres die – stamped on panels, forming the filtering curtain, that give direction changes to the air flow and then lap the viscous surfaces coated with the adhesive oil. The filter utilizes the viscous impingement principle of air filtration. A drive motor actuated by a timer is rotating the curtain with intermittent operation: a rotating time and a stopping time. This intermittent rotation improves the self cleaning action of the panels, that happens by single immersion in the adhesive oil bath, and renews the oil film with the recover of the oil excess, before the panels are crossed again by the air stream. The dust removed from the air by the curtain and washed from the panels settle to the bottom of reservoir as sludge that can be normally removed by a hand – scraper or, on request, through an automatic oil cleaner. Some oil is lost each time the sludge is removed and a small supply of oil can be necessary to maintain the proper level to allow the complete panels submersion in the oil bath.

Accessories
On request the filter can be equipped with an automatic external oil cleaner that permits to separate the viscous filtering oil impurities.

Installation
The automatic viscous air filter is completely erected and thoroughly tested directly in the Filtrotecnica Italiana factory, it is designed for vertical installation and with one only direction of air flow . The erection is very easy: arrange in advance a level floor, set – up the sections and bolting them together and to the plenum or to the filter housing with perimetric flanges considering that, front and rear of filter, a free space of at least 900 mm is desirable for servicing operation. At the end connect the control box to the electric driving motor and to the electrical supply.