Principle

Filter

A dust laden gas flow through the filter from outside to inside and the powder is collected at the outer surface of the filter. Gas passing through the filter becomes the “cleaned” gas and the collected powder is discharged to outside though the discharge outlet. Usually cylindrical felt fabric filter is used, however, space saving type, pleated elements (K type) has a larger filter area per unit and can be utilized well. In case of felt filters, metal retainers are inserted inside to hold the cylindrical shape. Filter material is selected depending on the type of powder, gas temperature, and gas composition.

Blow-off mechanism

Consists of a header pipe where compressed air is stored, diaphragm valves which blow-off the air in the header pipe in very short time, pilot solenoid valve which exhaust a little amount of air to activate the diaphragm valves and blow tubes through which compressed air is discharged to the filters. Suitable cleaning cycle specification is decided depending on total filter area and the pressure of the compressed air.

Housing

A top plenum which holds the blow-off part, a tube sheet which holds filters and separates clean and dirty sides, a straight body part which contains the filters, and a hopper part where powder is collected and conveyed to a discharge. Material is selected depending on the application of the powder, gas temperature and gas composition. Usually general purpose rolled steel (SS400) or stainless steel is used as construction material.

Timer

It contains the circuit board, which controls the pilot solenoid valves and sets the on/off time. Options can be selected such as display of pressure drop across the filter, differential pressure control mechanism, which activates pulse-jet when the pressure drop reaches the predetermined pressure, or differential pressure signal transmitter.

Discharging

During operation there is a differential pressure between inside and outside of the bag filter, the internal collected powder should be discharged while correctly air-locked. A rotary valve is a typical discharge device, it has a revolving rotor, which has discharge pockets. By minimizing the clearance between the rotor and the casing gas flow leakage is minimized.

Features

Applications

• Nuisance venting
• Exhaust gas from incinerators
• Exhaust gas from boilers
• Venting from entire sheds
• Oxygen production plant
• Exhaust gas from zinc plating work shop
• Exhaust gas from metal melting pot
• Exhaust gas Powder painting booth
• Exhaust gas from diesel electric generation
• Product collection from pulverizers
• Product collection from classifiers
• Product collection from dryers

Specifications

Fig.3 Dimensions of SP

Other information

Option

Pleated Filter

Pleated filter stocking has more than twice filtering area than the ordinary felt filter. This makes smaller installation space than conventional bag-house. Easier mounting of filters in bag-house than the conventional technology.

Discharge

RV-20K

A rotary valve driven by motor with reduction gear. Required power is small compared to the capacity. Assembling and disassembling is easy. Rotor capacity is 7 liter/rev.

RV-20IND, RV-30IND

A rotary valve driven via. chain by motor with reduction gear. Two models are available, RV-20IND with 7liter/rev. rotor and RV-30IND with 28liter/rev. rotor.

HUV type discharger

The HUV Type (Horizontal Unloading Valve) discharger is mounted at the bottom of the bag filter. It scrapes off the powder accumulated on the bottom of the bag filter by vanes and sends it to the discharge outlet. Usually a rotary valve is used to ensure an air-lock is maintained. It is used for materials, which tend to form bridges or in the case where there is height limitation.