Tiny Roots.

Today, most neon shops use the regenerative style or “ring compressor” type of blower to supply air to their torches.  Depending upon the size, these may be relatively quiet–or roar like a jet engine.  They work well, have an output free of pulsations, and do not require oil.

In the past, however, the Roots blower was the standard type used.  In many older shops, you are still likely to see them.

The Roots type blower was developed in the mid to late 1800’s by Francis and Philander Roots.  They had decided to set up a mill in Connersville, Indiana and soon found that their water wheel was not powerful enough.  Philander then set to work on a new sort of water motor.  Unfortunately, it was made of wood and when wet the wood swelled and caused it to jam.  While studying the problem one of them spun the rotors causing a blast of air to blow the other brother’s hat off.  The concept was promptly redesigned to supply air for blast furnaces, mine ventilation, and other applications and a patent was granted in 1860.  Or at least that is the legend associated with the development of it.

By 1900, Daimler had patented a variation for use as an automotive engine supercharger.  Such blowers have since been employed in various forms for Diesel engines, top-fuel dragsters, and a myriad of other applications in both engines and industrial air and gas boosting needs.

The concept is simple enough:  A pair of lobed rotors in close proximity are rotated in opposite directions within a fitted housing.  As the lobes pass a port, they pull in some air and sweep it through the housing and to the output side.  Two, three, and even four lobed rotor designs have been used.  Some also have a screw like twist to the rotors to reduce some of the pulsation effects.  This is a positive displacement blower–each revolution moves a fixed volume of air.  Maximum pressure is usually up to a factor of 2 and efficiencies in larger units can approach 70%.  (often a larger unit turning a little slower for a given flow rate can be more efficient than a smaller one turning faster for the same flow and pressure conditions)

The Roots blower I have here is a small one.  Maybe not the tiniest they made, but likely close to it.  It is a vintage unit that was made just prior to the US entry into the war.  This one was obtained from my friend, Jack Hasley–a neon tubebender in Arlington, TX with over 40 years of experience.  He had gotten it from his mentor in the early 80’s but had not really had a use for it because it was too small to run the burners in his shop.  (It is small enough that I wonder if it was originally intended for use as a gas booster rather than a primary air blower.) An interesting design feature of this one is the use of external bearings with grease cups and an outboard gear case-most larger and newer ones had the gearbox and bearings integral with the rotor housing casting.

In any case, I have the perfect project for this.  I have, for quite some time, wanted to build a small portable neon plant.  Small as in tiny.  Tiny enough to have all of it mounted into a pair of roll-around carts and fit in a closet or trailer.  Perfect for doing tiny projects and demonstrations to introduce others to the magic of neon.

There are a lot of ways to go about such a project, some using larger and newer parts……..but ….well, that’s just not me I guess.  I am also a collector and historian of such things and wanted to create something functional but with vintage components.  …and I want these components to be visible to onlookers (as well as myself) because the tools and equipment of that era are well made and have a pleasing style.  This blower is a perfect size and correct vintage to run the set of tiny torches I found from the 1930’s.  It should all mount up into a small cart with a fold-out work surface for doing glass bending work.  I will then build a similar cart that holds a vintage vacuum pump, manifold, and small bombarding system.  All sized to be easily transported.

Why?  Why not?  It should have some practical application at shows and would certainly draw attention…but more than that it is just fun and it makes a workable living display of some of my vintage tools that are seldom seen today and which many have never heard of.