Power required in roller chain conveyor

[Ivan Silva]

As the title says, I'm trying to evalute the amount of power needed in roller chain conveyor. I know there is engineering manuals regarding this calculation although it mostly aimed to grain/mining bucket conveyors but in my case it's not an grain it's biscuits and the manner the biscuits are transferred from the conveyor toward any other place doesn't follow the bucket conveyor manners. Besides it's I'm not interestedc in the formulas but in the physics behind it.

Contextualizing...

In the video below you can see the upper conveyor conveying biscuit just like my project intend to do. See timestamp from 1:14 to 1:21.

https://www.youtube.com/watch?v=znqSUwXYojY&t=26s

I'm first year engineering student and mechanical technician with some knowledge of physics and machine design, that's been said I think the calculation needed to evaluate the required power depends uppon the torque need to overcome the inertial momentum associated with sprocket gears, shaft, and any intermediary rollers when all this is accelerated by a given angular acceleration, the torque required to overcome the conveyor inertia (generated from chain mass, biscuit mass, friction between chain and its guides and the friction between biscuits and the stationary plate) as well as the angular velocity which the main shaft must rotate to accomplish the task and any safety factor or machine element performance factor.

Am I right? Is there anything else which needs to be taken into account?

 

[3DDave]

Almost all of the power goes into friction, in particular between the conveyor and the conveyor guides and supports. The amount for inertia isn't likely a large consideration except during startup.

If there is a large change in altitude for a large mass of product that might aid or resist depending on if it is downhill or uphill.

Welcome to the rewarding segment of engineering - adding up all the little contributions to get an estimate.

 

[JohnRBaker]

While I can't comment on your issue, it is interesting, that back in the 70's, I worked for the company that held the patent on using accordion-style vacuum cups to pick-up food products. If you picked-up a box or light bulb you were OK, but if you picked up any sort of food product, be it manufactured as in 'baked' like your 'biscuits' (AKA cookies), or something natural, like eggs, then you owed our company a royalty. Note that we manufactured bakery equipment including bread depanners (for taking a freshly baked loaf of bread out of a pan), and so we chose to use a moving belt of vacuum cups, which we developed to grip the top of the loaf without damaging it and thus was born the accordion-style vacuum cups, which we patented. The joke was that often we'd make more profit if a competitor sold a vacuum depanner then if we sold it, because they would have to pay us a royalty and when the customer had to replace one or more of those vacuum cups, because they would get damaged or worn-out, we'd get a cut of every one sold. Good business if you can get it (I'm sure the the patent has run out by now).

Here's what one of our bread depanners looked like:

And a close-up of the cups:

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Compositepro]

The conveyors in your video never start or stop. They run all the time, and the trays are stopped while the conveyor slides under them. Thus the power required is given by the weight on the conveyor, and the friction, and the speed.

 

[tygerdawg]

Many gearmotor manufacturer's Catalogs or Engineering Guides address how to size their units for applications like this. SEW-Eurodrive, Nord, Dodge, Bonfiglioli, others. Companies often offer some sort of sizing program. There is a PDF document on the internet named The Smart Motion Cheat Sheet that has many of the equations of motion for this.

In summary, a motor is sized for the power required to deliver the various torques, all summed together, to get Peak Torque:
[ul]
[li]accelerating & decelerating rotational inertias[/li]
[li]accelerating & decelerating masses in linear motion[/li]
[li]moving inertias and masses in steady state[/li]
[li]overcoming friction, bad attitude, phase of moon, insufficient whiskey, whatever it is that tends to impede motion[/li]
[/ul]

Peak Torque needed to get it all started from zero rotation. Or to change conveyor speeds. A lesser torque is required to keep it moving. But torque is cheap, so use plenty of it.

TygerDawg
Blue Technik LLC
Manufacturing Engineering Consulting

http://www.bluetechnik.com