High Temperature Blower - Streamlined Inlet

This is another picture of the back of the High Temperature Blower which better shows the Inlet Flange.  In this version the Inlet is attached from inside of the case.   We are currently fabricating an updated version which will be fastened from the outside.

We are working on moulded ceramic insulation but those efforts are not yet worthy of a picture.  To date we have used Cerawool Blanket, ceramic hardboard, and aluminized high temperature fiberglass.  The process is tedious because of the numerous cuts (not all on the insulation) and the challenge to fitting the material to such a "curvy" object.

The unit pictured below has been working 8 hours at 250°C  nearly everyday.  The version, not using the Curved Inlet, is nearly two years old but is used more lightly, though at the same temperature.  A third unit has been used for testing purposes but will soon be used on a nearly daily basis.

A new Inlet Flex Connector has been fabricated and it will soon be tested.  The aim is keep the sound level as low as possible.  We have had a measure of success in accomplishing that.  Last week CBC Radio aired an interview that was done just in front of the working Roastaire.   Obviously more improvements will be implemented to make the work area as pleasant as possible.

High Pressure Hot Air Blower - Add-ons

We have been reworking the Blower Inlet to improve the air flow and to make the design more compact.  The picture does not show that the Air Inlet has a circular flange but upcoming pictures will better demonstrate those features.

The Air Inlet can be rotated in 45° increments to accommodate various applications.

                                          

The Impeller is balanced to better than G.4 standard which is often referred to as gyroscopic level.  The Blower in our application is nevertheless mounted on 2" Rubber Mounts while the Inlet and Outlet are equipped with Flex Pipe to reduce the transmission of vibration from the turning components.  The Flex Pipe photo, above, is the Outlet Connector.  It is rather short due to a constrained space available. Where more space is available a longer Flex Connector can be supplied to add flexibility in the connection to off angle sources or destinations.

Previous attempts to use rolled Flexible Exhaust Pipe resulted in leakage especially at the flange connection.

The Blower output was higher than the expected requirement therefore we were able to reduce the Blower speed to approximately 12,500 rpm.  It is an approximate number due to memory rather than ability to measure accurately.  This modification significantly reduced the background noise generated within the workspace.  The vacuum pulling capacity is still fulfilling the requirements.

Roaster Carbon Calculations

The good people at Fresh Cup used the U.S. EPA Carbon Calculator to compare the Roastaire Carbon Footprint with that of a gas roaster.   

A 100 lbs.  of roasted coffee = 1 car off the road for 16 days  

This is how our roasting method impacts the environment. The energy ratio is  2 light bulbs versus the drum roasters 48 light bulbs.  Gas is a cheaper form of energy therefore in dollar terms the approximate heating cost of a gas fired roaster with afterburner is 16¢ per pound vs. the 2.5¢ for the recirculating Roastaire.


Evidently the Roastaire is way more environmentally friendly and cheaper to operate.  


The 100 lbs. of roasted beans represents about 3 hours of roasting, depending on the degree of roast.  Think of the savings to the environment and to the owner.  


It's time for a cup of freshly roasted coffee and a read about selling carbon credits.

High Pressure & High Temperature Industrial Blower

The suggested applications required either high temperature or high pressure but not both.  Googling the terms "high pressure" "high temperature" Blower brings up every type of air mover imaginable.  The designations are quite "loosey goosey" and often stretched so that it will accommodate the particular product being offered for sale.


I expected that this blower rated at 250°C would be at the bottom end of high temperature blowers but no - some units were given the same designation yet could only operate at temperatures that were 100°C lower.  


Some units had operational ceilings that were twice as high as what this one was tested at but their "high pressure" turned out to be .3 psi or 2,070 pascals which implies that it turns relatively slowly.  Low speeds are attainable with off the shelf bearings.  Therefore, it is not a niche that is of interest.


The version pictured is currently on the test bench where it is subjected to high temperature moist air.  Previous tests of off the shelf blowers demonstrated bearing corrosion in less than 100 hours.  It is possible that had it been a continuous test the bearings would have survived longer but running tests that lasted a few hours compromised the bearings too soon.


We are currently using the blower to fluidize and roast beans (coffee and others).  The pressure output of over 1 psi ( 6,894 pascals ) at 250°C  could certainly fluidize denser materials at a lesser depth.  At these temperatures the blower could be the heart of a monstrous pop corn pumper.  With continual introduction of kernels the output will compete with Vesuvius.  Such a machine would have to be brought to corn country Taber for testing.  


A recycled hot air requirement is fundamental to this niche, otherwise it is more efficient to heat the air after the blower i.e. an air knife.  Now, if a high temperature air knife was in a closed system nearly every blower in the marketplace would be inappropriate.


Hot air accelerated drying in an industrial setting would require a moisture extraction process but if it is a recirculated hot air application this is a custom application.  


Have a freshly roasted coffee and think of another application for the unit.