No one can from the information provided.

The calculations need details of the line, size, length, number of bends, gas pressure available, etc.

If you can give that information you may get some assistance.

You quote a figure of 55 cum/mm, what is this? Is it the gas flow which could be in cum/min? ■

The equipment is rated as having a duty of 55m3/min at a static pressure of 500mm wg. The duct has two 90 degree bends and two 45 degree bends, the ducting diameter is 304mm and the powder is conveyed a distance of 10m from ground level to a height of4.4m. I hope this information will enable you to provide me with an answer to the possible throughput of 300kg of recycled PVC powder per hour.

Regards

Nigel ■

55 cum/min in a 304 dia duct gives a fairly low velocity, only about 12 m/sec and in this size duct, with 300 kg/hr you have more of a dust extraction system than a conveying system.

It is likely that your fan isn't up to the job of conveying in that size line.

I assume that you have always had this problem and or it is a new system, it isn't that the fan or filter performance has deteriorated with time is it?

Assuming that is the case, rather than relying on theoretical calculations in this case, I would suggest:

1) Measure the empty empty line pressure

2) gradually increase your conveying rate until you start to see system problems. At that point measure the pressure and conveying rate.

3) The pressure and fan curve will allow you to calculate the minimum velocity that you need for your particular system.

4) The difference between the empty line and conveying pressures and the maximum conveying rate achieved will allow you to calculate the effect of conveying rate on pressure and the expected additional pressure at 300 kg/hr. Assuming pressure to be proportional to rate should be adequate here.

5) 3) and 4) above will allow you to specify the duty of the fan / air moving device you need, with a suitable safety margin of course.

6) If you can't find an air mover to do the required duty, you may be better taking out the fan and ductwork and considering a more typical conveying system with higher velocities, smaller conveying lines and a higher differential pressure exhauster. ■

Thanks for your help guys much appreciated

Nigel ■