Calculating screw conveyor flowrate 2

[mmcreleng]

Hi

I have a screw conveyor, but no idea of the flow it can provide.

Please assist with a formula for calculating flow rate.

Cheers

 

[nnjunger]

There are charts available, but we need to know the loading that you desire, the size of the screw conveyor, the pitch of the screw conveyor. Then the charts will give capacity of cubic feet per hour per rpm. You can then use this up to a "maximum economical speed". Martin, Conveyors Inc, and I am sure others all provide these charts. Hope this helps.

 

[mmcreleng]

Hi

Thanks for the suggestion. Had a look at these tables before posting. I have the screw already (& it isn't a standard size) - just need to calculate what volume flow it can deliver.

Thanks for the post

 

[nnjunger]

The only thing I have been able to do at that point is plot out the various sizes on a graph, and then pick a point on the curve. Interpolation would probably get you close enough for determining a production rate as well.

 

[RLJ]

Calculating screw conveyor flow is not extremely difficult, but it does take some figuring. The following works for solid materials. Liquids or sludges are another story all together.

First, determine your materials density Kg/Cu-M or Lbs/Cu-Ft. You want this to be consistent if possible. The following formulations can certainly be used with a varying denisty but it means that if you are looking for a consistent output you may need to vary the RPM of the screw.

Next do some simple math. Looking straight down the conveyor flights, subtract the area of the shaft from the area of the flight using it's OD. There are styles of flights that do not use a center shaft. In that case simply disregard its mathmatical removal. Multiply this area by the pitch distance and you have determined the 100% volume displacement per revolution of your screw conveyor. You obviously may or may not want to consider 100% volume.

Finally, if it is an existing unit determine the RPM. If it is a new design then you can select the RPM.

With all of this data you can create some simple equations to determine your flow rate.

We use this process all of the time and it tests-out in the field.

I suggest creating a simple excel spread sheet that can accept these variables and off you go.

Drive selection, trough styles, feed and discharge chutes are each a whole story to themselves.

Martin Sprocket is a good source for more of this information.

Go get 'em!

RLJ s-)

 

[670225]

I am looking for a handbook, references or someone who has the knowledge to calculate shaftless spiral conveyors horizontal up to vertical the flow + the needed horsepower for various products - urgent