With the right kind of air flow and some tubes to carry the material, you can send freshly milled flour whizzing across the building without exposing it to the air or paying an employee to push a cart back and forth. This technique is known as pneumatic conveying, and centrifugal blowers work best for producing the displacement needed for a strong vacuum suction. Pick the right blower for your conveying system from a supplier like Compressor-Pump & Service, Inc. with these five important tips.
Look for a Closed Interior
Contaminated flour is impossible to clean and sell when the particles absorb lubricating oils from the blower or get mixed up with dust from the mill. Stick with blowers featuring completely sealed interiors to keep grease and dust out of the stream of clean flour. Trying to use a blower built for industrial purposes could ruin thousands of dollars worth of stock before you discover the contamination problem.
The same seals that keep oil out of the flour prevent the particles from creating friction in the motor too. Of course, the rest of the conveying tubes, valves, and feeders need airtight seals too or you'll end up with dust coming in along the way.
Try Backwards Blades
While all centrifugal blowers spin blades to create the air pressure you need for moving flour, the shape and arrangement of the blades affect the amount of pressure produced and the energy required to create it. Pneumatic conveying is already an energy intensive way of transporting materials, so choosing a blower with the wrong type of fan inside it could leave you spending more than necessary on electricity. Look for blades that curve backwards against the rotation of the fan to create as much pressure as possible in your ducts while using as little electricity as possible.
Cool the Flour
Freshly milled flours are full of nutritious oils from the wheat kernel. These oils start breaking down quickly due to light exposure, but excessive heat also leads to rancid oils and a bad tasting flour product. Keep the flour cool as it travels through a pneumatic system by
- Increasing the air to particle ratio so that the flour is separated immediately after milling, allowing for rapid cool down
- Cooling air before it enters the blower to control temperature throughout the pipes
- Investing in blowers designed for lean phase transfer, in which each particle moves separately instead of staying clumped together.
With careful adjustments, you can start transferring the flour for conditioning and packaging immediately out of the mill without another step to cool it separately. This greatly speeds up the entire milling process.
While a noisy and vibrating blower may not affect the flour, it still bothers your workers who have to listen to it for hours on end. Excessive vibration also puts stress on the pipes connected to the blower, increasing the chances of a break that leaves the entire mill covered in loose flour. Look for a blower with vibration dampening features like
- Permanently sealed bearings, which also reduce maintenance
- Thick rubber pads, perfect for absorbing the vibrations
- Direct drive motors, which connect directly to the fan with no gears or belts to start squealing after a few years of use.
Pick Programmable Logic Controllers
Finally, consider more sophisticated controls for the blower if you want the pneumatic conveying system to run without attention while your staff is off duty. Basic centrifugal blowers simply run constantly unless manually switched off. Integrated programmable logic controllers allow the blower to increase or decrease its own pressure and velocity in response to changes in temperature, humidity, or flour input. This prevents clumping and ensures even product quality no matter when the flour is milled.