Air circuit breakers are adjustable for instantaneous, short time and/or real time delay operation. These are divided into three basic types that include molded case circuit breakers, low-voltage power circuit breakers and medium voltage breakers. They are equipped with heavy-duty contacts, arc quenchers and an operating mechanism, which may be either manual or automatic. These use air as a medium to extinguish an arc. These are available in continuous current ratings from 15 amperes to 4000 amperes and voltage upto 600 volts. These breakers are suitable for lighting and power circuits as well as motor starting and running services.

Air classifier - Double cone type is used to centrifugal separate the coarse particles. The airflow of air classifier conveys the material from below between the external and internal envelope and subsequently reaches the upper part of the separator. The air while passing through the blades of air classifier, which are regulated, from the outside of the separator assumes a rotary motion and enters the central cone. With the centrifugal effect in air classifier the coarse particles [the heavier ones] are accumulated on the bottom of central cone and are then conveyed through a suitable pipe. These are used for a wide range of applications in paints, dye stuff, hydrated lime, clays, pigments, insecticides, and pesticides.

Air classifier - Whizzer type is a compact and dust tight machine for fine classification of various powdered materials. It is used to separate dry materials into different particle size fractions by their size, mass or shape. It is also used to modify a particle size distribution, remove the fines fraction of a material or the over size or coarse particles of a material or create two grades of material.

Modern air classifiers are used to separate the protein fraction from the starch granules of ground cereals and legumes, based on difference of size, shape, and density. The basic elements in an air classifier consist of a rotating plate and air circulation fan, installed in a special chamber. The basic forces acting on the particles in the air classifier are the centrifugal, the gravity and the drag force. The air sucked by the fan, removes the fine particles from the plates and separates them from the coarse particles. The selection of an air classifier for a particular application is dependent primarily on the separation efficiency required and the money and facility space that can be committed. The least expensive equipment is a vertical column that requires a minimum of space. The zigzag air classifier is taller than the vertical column unit and has internal veins that add to the cost. The horizontal air classifier can process materials having larger particle size than a zigzag unit; however it requires more amount of floor space.

Air cleaning systems are designed to reduce contaminant levels after contaminants become airborne. It can be designed to control PM (dust), gas-phase contaminants or both. A minimal level of air cleaning is used in most building to protect mechanical equipment from soiling. Separate air cleaning systems are commonly used with radiant heating systems. The general type of technologies used in air cleaners include mechanical filters, electronic air cleaners, and hybrid filters for the capture of particles, plus gas phase filters to control odors.