Dust Collector Design: Air Flow, Static Pressure and Power Fan

Dust Collector Design: Air Flow, Static Pressure and Power Fan - Dust collector is a dust suction or smoke causing air pollution from industrial processes such as melting material, welding, screening the flour, material falling from conveyor to another conveyor and several other processes important applications. In the dust collector, a dirty air filter will separate dust and air. Dust will enter the shelter, while the air out of the plant so that it can cope with air pollution. (If you want to know more about definitions, functions, principles and any types of dust collector, read more: What is a dust collector)

Dust collector can clean the air of many sources of dust and smoke, by performing right calculations will be known air flow needed to suck the dust. In this article I will explain how to design of dust collector system, especially on the calculation of static pressure and air flow required so that can know the power fan of dust collector. As for the other part calculation, I will describe in the next article.

Calculation of Air Flow for Dust Collector Design

Air flow is the volume of air necessary for sucking the dust in the suction area. We must decide a suction area before calculate the air flow. Suction area is the spherical zone which can reach air suction. The outer end of the ball is an area with a minimum speed of the air to suck the dust. Over the suction zone, the greater the volume of air flow necessary. We must put a suction area in place that has the greatest potential for dust presence. If the source of the dust is in a remote part of the intake would be more effective if we divide it into several sections.

Air flow in the suction area can be calculated by the formula:

Note:

Q_i      = Air Flow of Suction Area (m3/hour) 

V_min   = Air Speed Minimum m/s) 

A       = Wide of Suction Area (m2)

d        = Diameter of Suction Area (m)

Value of the air speed least for sucking the dust is depending on the type of dust, the dust density and size of dust particles.

If the dust collector is used to suck the dust at a certain point in the suction zone, the air flow of the dust collector is the sum of the air flow in each suction area.

Note:

Q_t   = Total air flow of Dust collector 

Q₁   = Air Flow in first area

Q₂   = Air Flow in second area

etc.

Calculation of Static Pressure for Dust Collector Design

Static pressure is a loss due to the air flow pressure pickup area to exit the dust collector system. The pressure loss can occur in the suction, pipe duct, elbow and cyclone. Calculation of static pressure refers to duct size.
If the duct is used in the form of a tube, the diameter of ducting pipe can be determined by the formula:

Note:

d     = Ducting pipe diameter (m)

Q_i    = Air Flow of Suction Area (m3/hour) 

v     = Air Speed in the duct (m/s)

Duct in the adjacent suction area must be combined in order to be more effective, as indicated below:

Size of conduit ducts 1 and 2 are calculated using the above formula with sufficient air flow of each suction area. Regarding the size of the tubes 3 is calculated by the formula:

Duct size to the inlet of the dust collector is calculated by the formula:

Static pressure of the dust collector is a number of static pressure at any point of the possible loss of pressure calculated with the following formula:

Static pressure in the suction area or free entrance

Static pressure in the straight duct

Static pressure in the elbow duct

Static pressure in the cyclone, its value determined is 800 Pa.

Note:

ΔP = Static Pressure (Pa)

v     = Air velocity (m/s)

λ     = Duct friction

l      = Pipe length (m)

d     = Pipe diameter (m)

γ     = Air density (kg/m2)

g     = Gravity (m/s2)

Calculation of Power Fan for Dust Collector Design

Calculation of power fan can use the following formula:

Note:

P     = Power Fan (kW)

Q    = Total Air Flow of Dust collector 

ΔP  = Static pressure (Pa)

η     = Motor efficiency

If a fan using a standard factory specifications, then you only need to give the data of air flow and static pressure for fan supplier and they will decide its fan.

That is a description about the Dust Collector Design: Air Flow, Static Pressure and Power Fan. If you find misconceptions in this post, please give correction in the comment box.