In many operations that involve handling powders, the powder is carried in a gas or liquid stream. Therefore, in order to extract the powder, it must be separated from these fluids, and this operation is called dust collection. Among these, the device that collects the dust with a filter like a vacuum cleaner is called a filtered dust collector (Bag filter).
Principle of the equipment
As shown in the structural diagram of the machine, an inlet for dust-containing air/gas is provided on the side of the housing, and the dust-containing air/gas flowing in from here reaches the outer surface of the filter inside the housing, where the powder/dust is collected on the outer surface of the filter, and only the filtered and cleaned air/gas passes through the filter and is exhausted from the exhaust port through the top plenum.
The filter is attached to the tubesheet inside the machine, and there are two types: a molded type and a sewn type that uses fittings (retainers) to hold the cylindrical shape.
The powder and dust collected on the outer surface of the filter are removed by the pulse jet backwash mechanism, fall into the hopper at the bottom of the housing, and are discharged out of the machine through the discharge machine (rotary valve, etc.).
Pulse-jet cleaning mechanism
The cleaning area is moved at predetermined intervals.
The pulse-jet cleaning mechanism efficiently and continuously removes powder and dust collected on the outer surface of the filter to eliminate clogging of the filter and ensure stable and continuous operation.
The mechanism of the pulse jet cleaning mechanism consists of a header pipe, diaphragm valve, pilot valve, blow tube, venturi, and timer (control panel) mounted on the top plenum.
Compressed air/gas (standard pressure: 0.4-0.7MPaG) supplied to the header pipe passes through the diaphragm valve and is ejected from the blow hole in the blow tube by the instantaneous action of the pilot valve. At this time, the Venturi effect causes the air and gas in the surrounding area to be entrained and injected all at once into the filter, causing the filter to vibrate violently and ensuring that the powder and dust adhering to the outer surface of the filter are removed.
In order to minimize fluctuations in the airflow through the dust collector, each filter is cleaned once every 1 to 3 minutes, and a cyclic system is adopted in which no more than 30% of all filters are cleaned at the same time.