Sunday, November 15, 2015

High Temperature Blower II

                                                High Temp. & High Pressure Blower II

Further to the 2012 post "High Temperature Blower at Work"and 2011 post "High Pressure & High Temperature Industrial Blower";  LEQ (Les Entreprises Quénétic Lée.) has been working on an air bearing package that will deliver the same pressure and volume but at higher temperatures.

High temperatures create a hostile environment especially to an object that must turn at high speeds.  Materials must be carefully chosen so that they will maintain their strength and hardness at the elevated temperatures.  Thermal expansion creates problems as well because not only do different materials expand at different rates but various components operate at different temperatures.  That "constant" X 10-6 per °C can really bite you.

Common bearings can handle high temperatures and high speeds but rarely can they do both in the same application.  The high speeds (above 10,000 rpm) mean that the components have to be dynamically balanced plus tight tolerances have to be maintained.

The initial goal was to place the Blower in the coffee roasters where it should easily cope with the 250°C recirculated air.  Curiosity drove the project to higher and higher temperatures.  The current temperature ceiling will remain until a stainless steel housing is fabricated.

Earlier this week a blog reader  requested information on a blower capable of moving flue gases.  Unfortunately the 800°C flue gasses are 300° higher than we have been running the Blower, that temperature is beyond the capacity of the 6061 Blower Housing.  

There are some obvious applications for the Blower but it would be interesting to find out if it is able to solve or enhance some industrial processes.  Email your suggestions and requests.  Perhaps our development plans will coincide.

In the meantime we will continue to accumulate operating hours.

Friday, March 27, 2015

NXT Generation III Roaster

NXT Roasters Inc. is introducing its third generation advanced roasting system, which protects the purchaser’s investment, consumes the lowest possible energy, and exceed strictest air pollution standards Training time to roast is finished in days instead of months!  Its two-step roasted coffee bean cooling system provides outstanding repeatability of roast degree.

The System combines in a single unit:
  • A roasting and a heating chamber,
  • A chaff catcher,
  • Two afterburners,
  • Pneumatic conveyor to load green beans into roasting chamber, and transfer roasted beans to the packaging hopper

The NXT roaster is practically maintenance free, with threat of fire nonexistent!  Chaff from the air stream is separated prior air entering the heating chamber.  Roaster develops no tar deposits.


Batch capacity: 3 kg (green beans)
14.4 kg/Hr (roasted coffee beans)

Motor horsepower:
Main blower:                         2.2 kW
Pneumatic conveyor:             1.5 kW

Temperatures: Adjustable
Roasting: 235°C – 265°C

Main heater:                           10 kW
Smoke Eater:                         1.5 kW  
Power consumption:      6.0 kW / Hr.
Including Built-in Afterburners!

Cycle Times: 8 – 12 minutes

Dimensions: 50” x 36” x 80

Sunday, June 1, 2014

Improving a Working Device

Unlike a painting a machine can be tuned to new requirements without changing its fundamental reason of being.

An interesting book A Culture of Improvement: Technology and the Western Millennium written by Robert Friedel in 2007, reviews the invention and evolution of many technologies.  He certainly highlights that many factors determine the course of an idea and that it is not always the best idea that dominates.  In school,  history classes often gave the impression that there were technological leaps whereas this informed text demonstrates that more often than not inventors or the mechanically inclined stood on the shoulders of others, so to say.  Often people that leaped too far did not succeed for various reasons; people did not accept such a change, existing materials did not have the required properties, incompatibility  with existing technology, competitors sidetracked "message" etc.  In essence many aspects of a development have to be "done right" to assure success.

It is baffling that the author chooses to dismiss the work of Tesla while he lauds laboratory managers who were often credited with the inventions of employees.  Design of the distribution infrastructure of alternating current is only stated not credited.  Marconi's patent applications were turned down for years because of Tesla's existing patents.  His patent was only granted when well connected wealthy business people employed their power to influence.  It is not too different to where a federal government  concluded that the tomato is a vegetable that is subject to import regulations.
Meanwhile back in the present the challenge is to find an acceptable balance between the best technology and the price of implementing the solution.  To improve the efficiency and greatly reduce pollution the roasting air is recirculated after purging it of nearly all the smoke.  Sounds simple enough but the reality of working in a hostile environment is challenging.  

Fluidizing the bed of coffee beans is essential to the proper mixing and even distribution of heat.  In the upgrade shown on the right the Blower bearings have a lubrication system to improve the Mean Time Before Failure which usually happened too soon at roasting temperatures.

The continual cleaning of the recirculated air means that the roaster does not emit smoke during the hot weather roasting process.  A distinction is made regarding the weather because when it is cooler steam is vented during the bean cooling process.  Such a roaster can be used in higher density areas thanks to the built in pollution controls.

Of course the great smell of coffee is not to be wasted therefore we vent the air used to cool the coffee beans straight to the street to act as an olfactory business sign.

Sunday, February 23, 2014

Where to Next or is it NXT ? Suggestions?

It is time to refresh the blog but the subject matter is not "gelling".  We are working on upgrades but it would be premature to discuss a modification before they are introduced.  I am open to re-examining a blog or even attempting a new topic.  Send us an email about a topic.