Dear bikemaniac,

How about pneumatic conveying?

Why is the speed so important?

Have a nice day

Teus ■

Drop it under gravity ( v^2 = 2*g*h ) to get 20 m/s.

Use a high speed thrower belt to turn it 90 degrees onto your 20 m/s belt.

Job done! ■

Dear designer,

The particle density can be approx. 2x the bulk density = approx. 2000 kg/m3

A particle of size 1 mm (1000 micron) reaches a terminal velocity of approx. 5 m/sec.

A particle of size 4 mm (4000 micron) reaches a terminal velocity of approx. 10 m/sec.

Accelerating up to 20 m/sec cannot be achieved by gravity under atmospheric pressure.

Moreover, an open belt with a speed of 20 m/sec would cause the particle to be blown off the belt.

Dear Lucas,

Have you contacted: www.daltec-industrie.de

How about a very small, fast running, double belt conveyor?

Success

Teus ■

Originally Posted by Teus Tuinenburg

Dear designer,

The particle density can be approx. 2x the bulk density = approx. 2000 kg/m3

A particle of size 1 mm (1000 micron) reaches a terminal velocity of approx. 5 m/sec.

A particle of size 4 mm (4000 micron) reaches a terminal velocity of approx. 10 m/sec.

Accelerating up to 20 m/sec cannot be achieved by gravity under atmospheric pressure.

Moreover, an open belt with a speed of 20 m/sec would cause the particle to be blown off the belt.

15 - love to Teus ■

Originally Posted by bikemaniac

Hi,

I would like to ask the experts if the following is possible:

For an experimental prototype, we need to move a conveyed material at +20 m/s (twenty meters pr second or 4000 feet pr minute). The material should reach the conveyor from some sort of vertical silo or bin by means of gravity, a screw conveyor or by some other means. The main challenge is to accelerate the material from 0 m/s to 20 m/s within a very short distance.

What options are possible for such a challenge? I would think of a drag converter like this one would be interesting:

http://www.youtube.com/watch?v=8oJavTXN5Z0

What could you think of? Is it impossible?

Some data

Bulk density: 1000 kg/m3

Particle size: 1-4 mm

Moisture: 0%

Conveyed mass: Approx. 20 tonnes/hour. Remember this mass flow is VERY high due to the speed, but we only need a very small cross sectional area in the output mass flow.

Speed: 20 m/s

Overall length of conveyor system: Max 20 meters

Height of system: 5 meters

Power consumption: Unlimited

Wear: Wear problems are of no interest at the moment

Maximum operating time: 20 hours (it is a prototype)

Please ask if you need more info.

Thanks in advance, Lucas

Your mass flow is not that demanding lucas,

the pneumatic transfer of this material using

pressure gradients to transfer the material using

a positive displacement rotary lobe blower system

to generate the presssure gradient required.

Pneumatic transfer will work handily for what you

will need Lucas, as it will manage the demands

easily with a gate system-there is no need

to ponder this and reinvent the wheel. ■

I have seen a conveyor running at 1,000 ft/min carrying a low density material. The conveyor is fully enclosed and a fan pushes air in the conveying direction at the same speed as the belt. Terminal velocity problem solved as the material sees no relative speed to the air.

This material was flake like. If it is more granular, I wonder if this is still a problem because when you watch a slinger operate at around 4,000 ft/min, material does not stray once floe is established as it is following behind the piece in front. The same slipstream effect that racers try to take advantage of.

This belt used a concave acceleration belt at the feed point to use gravity & centripital acceleration to make the material grab the acceleration belt and gain speed without tumbling.

My biggest concern about a 20m/s belt would be the idlers. RPM would be high, likely requiring machining & balancing, and a special bearing design unless you were only running in short bursts. ■