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Join Date: Jul 2011
Posts: 3

# Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 6:37 AM

Hi,

I want to calculate the required capacity of lobe compressor to convey 2292 kg/hr green beans(coffee).

Specific density of beans=0.7,

Height to which it is conveyed = 19m

horizontal distance = 10m

Please let me know how to calculate the required capacity.

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#1

### Re: capacity of lobe compressor required to convey solid

07/29/2011 6:41 AM

It would be quicker to contact pneumatic conveying specialists directly rather than rely on CR4 readers. An internet search engine will find any number of potential equipment suppliers, who will quote their capacities in their budget quotations.

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#2

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 10:53 AM

2292 *9.8 *19= 426770 J/hr= 118 watt

1 hp would be a good starting point.

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#3

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 11:10 AM

For the second time this morning I get to say, "you should engage brain before typing."

The OP should take the advice of PWSlack. You should sit on your hands for awhile.

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Participant

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#4

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 2:23 PM

I want to know how much air flow rate should be provided by the compressor in m3/hr.

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#5

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 4:14 PM

I agree. Especially if the OP really wants to pump the beans 62.3 feet into the air.

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#6

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/29/2011 9:13 PM

For a small company in developing country, money and availability of technical expertise is always a constraint. The OP requirement is 2292kg/hr, so it is no where near those big silo system.

I think it is not a very difficult engineering problem , only require a bit of practical engineering approximation and experimentation, this is how you should go about doing it:

The force to move an object up an inclined path F=mg sin (angle of inclination),

The force due to air speed on a ball shape object F=1/2 * 1.22*V^2 *Cd*A; where Cd is coeff of drag (0.47 for ball shape); A is cross section area of bean.

From this equation, you get air speed v.

From bean flowrate Qb=2292 kg/hr=2292/700/3600=0.91 liter/sec, and given air speed v, you can find area occupied by bean flow, Ab; Ab=Qb/v.

Assume the bean flow will will occupy 30% of pipe area Ap, so you can find area of pipe, Ap= Ab/0.3.

So , the blower air flow rate Q=v*Ap

Watch out, above equation are in metric units.

Start with these approx values and adjust the RPM of the blower, flow rate is proportional to rpm. Motor power , from my earlier post 1 hp , perhaps to be on safe side, use 3 hp to give more room for adjustment.

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#7

### Re: Capacity of Lobe Compressor Required to Convey Solid

07/30/2011 12:45 AM

thanks a lot.

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