The World Of Positive Displacement Blowers  
 A Few Facts, Memories, and a Lot Of Nostalgia

 By: Mark W. Royston
La Mirada, California 1999

It Began in 1859

The positive displacement blower was first invented around the middle of the 19th century.  For those who are fastidious about exact dates, they are referred to a historical monument at the city limits of Connersville, Indiana, the home of the Roots Brothers.

As was related to me by others, the machine was first invented as a more efficient water wheel.  Made of wood, it was put in the millstream and as the water flowed through it, the rotors turned and power was generated for milling from the output shaft.  It worked well except for a minor flaw; the wood would swell up and ruin the clearances and the mill would stop.  The unit would be taken out of service and dried out, shrinking the parts to their original dimensions.

In an effort to speed up the drying, as soon as the rotors would turn, a power source could be connected to the output shaft and the rotors spun.  Someone noticed that such an arrangement would move a quantity of air and the use as an air blower was begun.  Over the years the liquid pump version has persisted and today there are versions of the positive displacement liquid pumps in operation.  They are used mainly as transfer pumps to handle large volumes of liquids at moderate pressures.  In their simplest form they could be considered as a “two tooth” gear pump.

First Blower Application

The first air application was as cupola blowers.  While the pressure requirements were low compared to today’s needs, the positive displacement blower’s ability to supply a constant volume of air over a varying pressure range made it ideal for the purpose.  Another early and interesting application was as an air source for player pianos and large organs.  As time went on the positive displacement blower gained a good foothold in industrial applications, replacing the centrifugal blower on its high end and the compressor on its low end.

The engineering of applications was simple.  While the horsepower requirements of other air moving or compressing devices varied with the inlet pressure, temperature, or gas density, they did not with the positive displacement blower.  The horsepower was a function of the displacement volume times the differential pressure.  While variations in these conditions might change the volumetric efficiency of the blower, the horsepower formula didn’t change.  As time went on, this would make the positive displacement blower ideal for certain applications.

By 1930 there were three blower companies in existence in Connersville, Indiana: The Roots Blower Company, The Connersville Blower Company and the Wilburham-Green Blower Company.  In a rash of consolidation rare in those days, they decided to quit fighting for business and join each other.  For a period the amalgamated mess was known as the Roots Connersville Wilburham Green Blower Company.  After a period, it became, as it is known today, the Roots Connersville Blower Company.

How Sutorbilt Came About

The merging of the three companies was responsible for the formation of another.  As one might guess, sales were made through Manufacturer’s Representatives and there was one for each company in most major cities.  Now that they were one, there was need for only one representative.  The merged companies made a move in the Los Angeles area that would haunt them from that day forward.   One of the representatives let go was the W.F. Sutor Company.  William “Bill” Sutor was a well liked representative in Southern California that handled such varied lines as Dongan Electric, and Atlas Car and Manufacturing Co. The positive displacement blower business was a growing one as the chemical and petroleum plants began to make the L.A Basin and the High Desert a good outlet for blowers.

One of the employees, Robert S. Clark, was a Naval Academy graduate, Class of ’26. He had retired from the peacetime Navy and was engineering and selling for Mr. Sutor.  Later he would become the owner as Mr. Sutor suffered from Parkinson’s Disease.

Original Equipment Manufacturers (OEM) were rare but there was one in Pomona, the Brodex Company.  They manufactured a line of paving machines that needed to burn crude oil to generate the necessary heat to process the asphalt.  Every machine made needed a small positive displacement blower to atomize the oil.  While the size was small it did represent a predictable volume.

W.F. Sutor Company also had a machine shop.  They were in the business of “re-grooving” flat belt pulleys to the recently invented “V-Belt” drives.   They also fabricated and machined oil well pumping jacks.  While the machine shop was not large, it was capable of machining castings of an item, such as, say, a blower.

First Sutorbilt Blower Sale

Brodex was approached with an idea.  If W.F. Sutor were to manufacture a blower, would you buy it?  The answer was, “yes, if it works.”  Thus W.F. Sutor was in the positive displacement blower business.  Now 1930 was not the time to be in any business, let alone a new manufacturing business.  Two things saved them, the Repeal of Prohibition and World War II.

When Prohibition was repealed most breweries were in a sad state of disarray.  When they were rebuilt, modernization led them to adopt a new method of grain handling.  Out of Europe came the pneumatic conveying method of material transfer.  While it was not as efficient as mechanical methods, such as drag chains, and bucket elevators (Remember, the front end loader hadn’t been invented.), pneumatic conveying allowed the source or pickup point to vary (using a vacuum pickup) and the discharge points to be switched by the use of pipeline diverter valves.  A messy operation became a clean one.

Other applications became evident and shortly many pneumatic conveying applications became evident.  While Roots controlled the larger, more status minded companies, Sutor became quick on its feet and learned the application engineering necessary to recommend blowers to the pneumatic conveying industry.  In the thirties only a few companies were in the pneumatic conveying business.  Most had backed into it because of other uses for their products.  

The largest of these pneumatic conveying companies was the Fuller Company, in Catasauqua, PA.  Colonel Fuller was the majority stockholder of the Allentown Portland Cement Company.  The cement industry needed a company to engineer products that would meet the challenges of the abrasive environment of its manufacture.  He created the Fuller Engineering Company for that purpose.  By the thirties, it was well entrenched in the art of pneumatic conveying in the cement industry.  The cement conveying varied from the grain handling in its pressure requirements.  Since cement was abrasive, the method of introducing it into the conveying line varied from that of the grain handling systems.  One of the breakthroughs came from the invention of the Fuller-Kenyon Pump.  This device used a screw to push the cement into the conveying line where it would be carried away by the air stream.  Since the air also wanted to take the path of least resistance, a method had to be found to keep the air from escaping back through the product input.  The Fuller-Kenyon Pump solved this by varying the flight of the screw, so that the first part of the flight wanted to handle more than the later parts.  This compressed the cement into the barrel of the pump and created its own seal.

Cement could be conveyed at lower velocities than other products and because of its finely divided particles, it would take on the semblance of a liquid, as it was pushed through the pipeline.  (Today, this would be known as dense phase conveying, while the handling of products with larger particles would become known as dilute conveying.)  The cement was carried for long distances and a compressor was needed to provide the air power.  Pressures were up to 30-35 psig and well beyond the capabilities of a positive displacement blower.  Reciprocating compressors were available, but were normally used in higher-pressure applications.  (Such as plant air supplies.)  The search for a compressor to match the Fuller Kenyon Pump led Fuller to France and the rotary compressor.  As it was manufactured in France, it used thin steel blades to separate the rotating cavities as the eccentricity of the rotor from the cylinder compressed the air as it rotated.

Most of the dams that were built as public works projects in the thirties had Fuller-Kenyon pumps that would transfer cement for miles from the cement source to the dam site.   (Other products for the cement industry were a part of Fuller, but it is the pneumatic conveying that matches it with the positive displacement blower industry.)  

W.F. Sutor gave their blower the name of Sutorbilt.  Early advertising slogans were “Sutorbilt is well built” and “Go there for air.”  As their manufacturing increased, the attention to the Representative business fell off.  They added to their product line, items that were needed to complete a pneumatic conveying system.  (If the conveying companies wouldn’t buy this new fangled blower, then Sutor would build complete systems.)  By the end of the thirties, Sutor was the authority on the handling of the more nasty products such  as cotton seed, (both linted and de-linted) cottonseed meal, cottonseed hulls, wheat and grains.  They also built large portable systems that were used to unload Copra (dried coconut meat) from ship holds.  Many of these operated in the ports of Los Angeles and San Francisco as well as at such manufacturing plants as Proctor and Gamble in Ivorydale, Ohio.  Each of these products had characteristics that made them difficult to handle, but Sutor endured and fought them through.

World War II

When World War II started, all manufacturers of positive displacement blowers were called to the war industry.  The need was for vapor compressors.  Each detachment of soldiers and each ship needed dependable fresh water to carry on the war. The solution was a “water still” and the most popular one was one that created fresh water using a partial vacuum to reduce the boiling point of the liquid.  The water was heated and a vacuum created by the “vapor compressor” pulled off the steam, which was then condensed into fresh water.   This process was called the Kleinschmidt cycle and  the vapor compressor was a modification of the positive displacement blower.  Outboard bearings and stuffing boxes were used to isolate the bearings from the steam.  The materials of construction were bronze or Naval Brass.  Besides Roots and Sutorbilt, General Motors came in as a supplier as they had developed a line of positive displacement blowers used to supercharge large engines.  Vapor compressor sizes were tailored to match the needs of the “still” manufacturer.  Thus odd ball sizes and gear diameters were common. 

War’s end found Sutorbilt with a lot of bronze on hand.  Parts were going through and all of a sudden the orders stopped.  The government called a halt to the orders, paid them for work done and they could do with the vapor compressors as they wanted. A lot of these bronze beauties found their way into industry, with no thought of the difficulty to match them to standard sizes as replacements were needed.  Actually the war surplus “stills” created a new industry, that of “mountain quality” fresh water.  Companies sprang up who purchased the war surplus “stills” and water which never saw the mountains was distilled and sold as mountain water.  Minerals could be added, salt content controlled and water could be produced to specifications not attainable from the melting snow and footprints of men who trod the mountains.   

Two companies continued to produce these stills, one in New Orleans and one in Waukesha, Wisconsin.  Later offshore drilling rigs and other remote exploration sites continued the demand for the water stills.

Vacuum to Increase Oil Production

Somewhere in the thirties and forties the “well vac” came into existence.  The Los Angeles basin was filled with oil under the ground.  Southern California areas such as Signal Hill, Santa Fe Springs, Tonner Canyon, Coyote Hills, South  Main Street and the West Side were pumping oil at an expanding rate.  As some of the wells were depleted, it was found that pulling a vacuum on the casing could increase the output.  A positive displacement blower was just the answer.  In addition, a salesman worth his weight would be remiss in not mentioning to the adjacent oil site that his neighbor had installed a well vac and its influence might, just might, extend beyond his boundaries and pull up a few barrels of his neighbors oil.  Thus a steady sale of well vacs was assured.

Fuller Company One of the First Pneumatic Conveying Companies

In 1949, the Fuller Company bought a company in Cleveland known as the Draco Corp.  (Dust Arresting and Conveying Company)  This is mentioned only because they had a line of inferior airlocks.  (An “inferior” airlock was one manufactured by someone other than the Fuller Company.)  Later on when Fuller bought Sutorbilt, the Sutorbilt line of Airlocks was discontinued, as Fuller had no need for two lines of “inferior” airlocks.  (If one would take a real close look at early editions of the airlocks made by Wm. W. Meyer and Sons, one would note the sameness of their design and dimensions to the Sutorbilt airlock as theirs was placed on the market shortly after the ones at Sutorbilt were discontinued.)  

By the early fifties, the Sutorbilt machine tools were getting tired.  Impeller contours were still ground by hand to matching sets.  There were three or four persons who did nothing but grind impellers.  By this time Mr. Clark owned the large majority of the  business  as Bill Sutor had left the business in 1946.  

The blower industry was never at a loss for new applications.  Well before my time in the late forties an inventor came into town from Minnesota.  He had invented an “Isomagic” ice machine that he could sell to every bar.  Imagine, ice cubes at your demand, pure and clear.  The clear part was the significant word.  Everyone knows that each commercial icehouse uses an aerator to bubble the air through the ice as it freezes to insure clarity.  Lots of positive displacement blowers were sold for this purpose.  Our Minnesota friend had a patent on the process and needed a lightweight blower to solve his aeration problems.  Since the pressures were light a new series blower with aluminum parts and a 2- inch gear diameter was designed and produced. Some 250 unusable model 2520 aluminum blowers began to gather dust on the shelves as the venture failed.  Since the aluminum parts limit severely the pressures at which a blower  can operate, there they sat, a monument to the “Isomagic” venture.   

The Uranium Craze

The Cold War came to the rescue.  The search for Uranium created a craze, not heard of since the ‘49ers poured across  “Californee” searching for gold.  The deserts of California, Arizona, Nevada and Utah crawled with uranium miners searching for that elusive element that until a few years ago was described in the dictionary as “a useless metal, not found in the U.S.”  Geiger counters were at the ready as a mass movement not seen since the “gold rush” days of the unemployed of the Great Depression made its way across the deserts.  Once a find was made, the  claim could be staked and then “proved.”  The proving was the tricky part.  A core sample needed to be taken and given to the assayer.  How to get the core sample was the problem.  The typical core sampling was done with a wet method.  There was no water on the desert and thus the need for a dry recovery method.  

Enter the scene a gentleman from the remote Simi Valley.  Reese Houston was his name although we promptly rechristened him “Sam”  (The name “Sam” stuck until finally he changed his legally.)   Sam had an idea.  A two man pack operation that would carry the core driller and the core remover.  All powered by a chain saw engine.  Not a bad idea.  He had the core driller working well. All that was left was a small lightweight vacuum to suck out the cuttings.  Lightweight struck a chord.  Why not try the Isomagic blower that only weighed 12 pounds.  After all there was no way he could use up 250 blowers.  We magnanimously loaned him a test blower and off he went.  Well, what do you know?  The damn thing worked.  It worked so well that he used up all 250 of the nice lightweight blowers and was asking for more.

Since I was the one who had come up with the bright idea to use the Isomagic blower, the plaudits turned to boos as production wanted nothing to do with any more lightweight aluminum blowers.  It fell to me to tell Sam that the blower on his backpack now weighed 32 pounds rather than 12, and to add a double Whammy, we wanted more money for the insult.  Sam was finally mollified, although it took a number of trips to that remote Simi Valley that, to that time, showed no signs of development and the only road in was a narrow two-lane highway through the Western town of Corriganville.  (Remember Wrong Way Corrigan?)  The Houston Tool Company went on to use a lot of blowers including some large ones that were used to suck up the cuttings after A-bomb tests in Jackass Flats, Nevada.  Finally the Uranium craze died down and Sam rode off quietly in the West.  Actually he didn’t go too quietly as he was helped along by his creditors.

The Cold War and Bomb Shelters

As was, and is, typical of the blower applications, one rises, another falls and you remember with nostalgia the “good old” applications.  I can’t leave the Cold War without talking about bomb shelters.  When it was obvious that we were going to be bombed back into the stone age, it was decided that the positive displacement blower industry would be the first to crank out the stone age machinery.   What does every bomb shelter need?  An air source!  What doesn’t every bomb shelter have after the big one? Electricity!  If you need air but don’t have power, that only leaves one answer, a hand operated blower.  Both Roots and Sutorbilt rushed one into production, with  Roots being a bit smarter than Sutorbilt.  They thinned down the gears, opened the clearances and put in thin oil.  Both had a crank handle and a speed up drive that brought the little monster to a performing speed.  You’ve heard the phrase, “Only the strong survive.”  Well, that would have been true with the hand operated Sutorbilt blower turner.  The power that would have been needed to keep that blower turning would have taxed the strength of a Charles Atlas  (To keep the comparisons in line with the date.)

Off both companies went to the trade shows that were replete with all kinds of survival gear.  Both showed off their new product and luxuriated in the sweet nothings of, “You’ll need 40 acres just for the parking as everyone  in the country will need one of these  babies.”  Of course, Sutorbilt had to send a larger crew to the show, as they took turns keeping that life saver up to speed, while they cursed the designer that settled on standard industrial parts and clearances, while all the time keeping potential customers from trying to turn it themselves.  

What was good for the world, Peace, prevailed and the bomb shelter business bombed and this was also good for the blower industry, as the funeral dirge for the bomb shelters was heard before 250 of those little, never to be sold, energy burners were placed on the shelves.   

Blower Designs

A little bit about blower designs.  Early blower designs had sleeve bearings.  This was an acceptable bearing surface, but since sleeve bearings wear, the impeller assemblies would drop and contact the lower case.  Cases for larger blowers, for the most part, were made in multiple pieces.  They would be rough machined and then machined as a set.  Final assembly called for two half cases connected with top and bottom plates.  While the machining was labor intensive, the assembly allowed for precise tolerances to be set.  This made for very efficient blowers that were later hard to duplicate as more precise machining methods and faster assembly requirements called for opening the clearances.

Up until 1956, maximum blower speeds were very slow, somewhere in the 1600 Feet Per Minute gear speed.  If requirements dictated higher speeds (such was needed in the Aerospace Ground Support Business), dynamically balanced impellers were added and maybe a thrust bearing. While small blowers had “spur” gears, larger blowers had “Herringbone gears.”  If a thrust assembly was required, a spur gear unit had two internal thrust bearings, while Herringbone units only called for one.  Many larger units had up to eight bearings which included four main bearings, double outboard bearings, located in the gear case on the outboard side of the gears, a single outboard bearing outside the drive sheave, and the ubiquitous thrust bearing.

Just listen to the instructions for setting the thrust bearing.  “Turn blower on and operate at normal speed.  Using a wrench, turn the adjusting screw on the thrust bearing clockwise.  Continue until the blower ‘hesitates.’ Turn back one full turn and lock the setting.”   I don’t know about you, but I was never about to turn a thrust bearing set screw until the impellers ran into the head plate.  (I would leave that to some pro like Johnny Salser, the main service man for the company.)  

How Blower Series Got Their Names

The naming of blower series didn’t use a lot of imagination.  The small blowers made by Roots were called the “AF” series.  That, of course, stood for “anti-friction,” as in “ball or roller bearings,” compared to the older design of sleeve bearings.  The large sizes were still a sleeve-bearing machine called “RCDH,” for “Roots Connersville” and a corruption of “Heavy Duty.”  When Roots came out with their larger roller bearing machine, it was called the RCR series.  The same Roots Connersville applied and the second “R” stood for “roller bearings.”  Clever, Huh!    The actual size of the Roots blower was an indication of the gear diameter and the impeller length, in inches.  Thus a 45AF was a unit with a 4-inch gear diameter and a 5-inch case length.  This naming of sizes went from their smallest to their largest, except for the two smallest gear diameters.  The 2 ” gear diameter was just “2” and the 3 “ gear diameter was “3.”  

Sutorbilt, generally followed the same naming of sizes in the larger units but deviated in the smaller sizes (Two through eight inch gear diameter) by having a number to indicate gear diameter and a letter to indicate low “L”, medium-“M”, or High-“H” pressure ratings.    Actually it was not unusual to make the units in “odd-ball” case lengths to fit a specific requirement.  From an engineering standpoint, naming the blowers by gear diameter and impeller (or case) length was good, because if one knew the gear diameter and case length of a blower, the displacement could easily be calculated and its performance laid bare.  Sutorbilt named their smaller blowers the “California Series” to add that Sunny California mystique, as they tried to capture a part of the Eastern market.

Sutorbilt Corporation Sold to The Fuller Company

In late1955, Mr. Clark sold the business to the Fuller Company, who were in turn owned by General American Transportation (The GATX you see on railroad tank cars).   While the marriage might be easily accepted as a good match between Fuller and Sutorbilt, because of Fuller’s need for positive displacement blowers in pneumatic conveying, what in the world is the connection between rail cars and the Fuller Company.  

Well, it all turned about a product called the “Airslide.”  Fuller Company had patented an item whose generic name was an “air activated gravity conveyor.”  Actually their patent didn’t cover the entire concept, but the porosity of the belting upon which the product slid.  It had been discovered that certain products, such as cement, would easily aerate and if you poured cement in on one end and pushed air up through the belting (another use for a positive displacement blower), the fluidized mixture would flow, like water, down a minimum slope.  Cement plants throughout the country rushed to put in this new method of transferring cement through their plants.   

After World War II, there was a move to modernize the method of transferring cement by bulk.  Fuller Company and GATX started a joint venture to design a railroad car that could haul a large payload and be automatically discharged at its destination.  The result was the Airslide railroad car.  Before it was through, in the late forties, General American bought out Fuller Company.   Later on, the Airslide car became the staple for handling bulk flour and other products as well.  (The bulk truck is another story.)   

Blower Quality Is Improved

The work to improve the quality of the blower continued.  The first operation that needed attention was the impeller profile.  The old and expensive method of grinding the contours was to be discontinued and replaced by a pure machining operation.  Cutting tools would machine one side of each impeller in a single cut.  There were many engineering meetings to determine the best profile for the impeller and finally a “modified involute” was chosen.  This was the easiest to machine and allowed the throat of the impeller to remain un-machined because by the time the impeller tip had entered the throat of the mating impeller, it had begun to seal in the other face of the impeller.  While this design simplified manufacturing, it did lead to some broken shafts and other damage in those applications where there was an inordinate amount of liquid in the air or gas stream.  (If your curiosity is aroused as to why this happens, this design makes for a changing of the volume in the throat area as the impeller rotates through its circle.  If there is a solid amount of water present, its incompressibility can lead to major damage to the blower.)

The Move Toward Increased Speeds

About this time in 1956 and 1957, there was a horsepower race that began in the blower industry.  To this time, the blowers were operating at low pressures and low speeds.  Roots came out with a blower design that was called the RAS (Roots-Air-Segmented impeller) and RGS (Roots-Gas-Segmented impeller).  These blowers ran at the unheard speeds of 3000+ FPM gear speed.  

Actually “unheard of” is a poor choice of words.  The old pleasant “chug-chug” of a blower operating was replaced by a scream that could be heard throughout the user’s plant and into backyards two miles away.  The blower became a low frequency noise generator and the only ones smiling were silencer companies such as Burgess Manning and Universal Silencer.  Combine this with the new government agency called OSHA and there was a rush to find the best type of silencer to do the best silencing.  The best design turned out to be a combination chamber-acoustic type that used the chambers to reduce the pulsation and the acoustic material to reduce the noise coming off of the silencer itself.   

Sutorbilt designed a matching blower for gear diameters of 10” and larger, calling it the 3200 series (named for the maximum gear speed of the unit.)  The smaller blowers in the California Series came in two varieties; one at the old series speed and one at a higher gear speed with dynamically balanced impellers and a small drive shaft mounted thrust bearing. (This high-speed version became known as the California Series “B”.) The thrust bearing was of doubtful value as it limited the space available for the drive pulley.  Some dimensional changes were made but kept to a minimum, so that replacements of old blowers could be easily done.  

An Unusual Application
One of the OEM applications that took a modified 5L was the laundry press blower.  A company in Utah had designed a faster and improved laundry press that used a positive displacement blower to draw off the hot steam and cool the shirt.  The result was a quicker process and a better-looking shirt.  Five to ten 5LS blowers made their way to Salt Lake City each week.  (The “S” on a model always indicated something special and the need to look at the original manufacturing card for that serial number.)  

The Growth of Bulk Flour Handling

One of the major industries that took flight in the fifties was the bulk flour milling and distributing.  Until that time milling companies sacked off their products into 100-pound sacks and the sacked flour was then shipped off to the bakery or consumer.  It was found that flour was one of easiest products to convey through a pneumatic conveying system and a new industry was begun.  Companies specializing in flour handling sprang up in the Mid-West from Minneapolis to Kansas City.  Since Mr. Clark and Bob Schneider were busy with their old customers and sales routes (which would take them to such industrial metropolises as Lake Louise and Banff), the servicing of these new customers fell on the shoulders of yours truly.  A typical trip would be to Minneapolis, Kansas City, Salina and Wichita.  A lot of life long friends were made as companies such as Flo-Tronics, Semco, Superior Separator, Salina Manufacturing, and Shick Tubeveyor came into being.  (It is well remembered a conversation in a coffee shop in Kansas City, Kansas with Bill Ungashick that maybe helped to convince him that he should quit as chief engineer of Crissey Company and start the highly successful Shick Tubeveyor .)

Some of the first bulk flour trucks ran out of Salina, Kansas under the name of “Econoflo”.  The actual owner of the company was Gooch Feed Mills, an extremely large milling operation owned by the Vanieer Family.  Their chief engineer and general manager was a gentleman named John Landis and he appreciated someone coming all the way to Salina from California so much that he purchased nothing but Sutorbilt blowers.   Not only that but he would place his orders with no one but Royston personally.  A cell phone would have come in handy in those days, as a lot of time was spent out of the office.

The beauty of it all was the education received.  As the pneumatic conveying engineering went from the “I hope it works,” to “I think it will work,” to “I’m damned sure it will work,” Royston was absorbing all he could.  Add to this the work in the dirty cotton gins and oil mills that was shoved off to the junior member and it wasn’t long before the knowledge of pneumatic conveying in the company was beginning to default to this same junior member.

Aircraft Ground Support Equipment

Other applications were found in the Ground Support equipment for both the military air bases and commercial airports.  During the late forties and early fifties it was an industry that would support a salesman to cover those applications.  There was pressure test equipment that would check out the airplanes piping systems for leaks.  There were ground air conditioners that would supply refrigerated air to keep the electronic equipment aboard cool (replacing the ram air that was introduced when the plane was in flight.)  Many of the jets required a large airflow at pressures in the 15-18 PSIG to start their engines.  One of the first jet starters was supplied by Sutorbilt and consisted of a double staged unit with blowers in the 12-14 inch gear diameter.  The unit was on wheels and it almost dwarfed the airplane it was starting. 

The largest application for positive displacement blowers in the Aerospace field had to be the ground air conditioner.  The specifications called for 100 pounds per minute airflow at an outlet pressure of 3 PSIG at the end of the hose.  Add to the package a 25-30 ton refrigeration air compressor, condensers, evaporators, portability and such and you have a somewhat sophisticated package.  Many thousand of these units were built, but the first production order for thirteen units, was built by Sutorbilt in late 1954.  The blower was an 8L running at its normal speed to put out around 1250 CFM.  The refrigeration compressor was a brand new designed York  “Vee” series.  Why do I know so much about these units?  I was the service man who ended up at the Douglas Aircraft plant in Tulsa Oklahoma when they didn’t work.  That was the longest three weeks I spent in my life.  I was  sent off by Mr. Clark with the instructions that the units needed a little adjustment.  A screwdriver and a quarter inch drill should be enough tools to take care of the project.  Might take two or three days. 

When I was met in the lobby by the chief maintenance manager and the vice president of manufacturing, somehow I sensed there was something more amiss than a few adjustments.  Somehow the damages received in shipment (created by the failure to properly tie down the units on the transporter) paled into insignificance as they got to the main point.  The damn things just didn’t perform.  The air was supposed to be at around 33-34 degrees  leaving the hose and entering the airplane.  The actual performing temperature was around 45-50 degrees.  Quite a difference.   Knowing nothing about refrigeration and at that time little about blowers (I think I had been on the job at Sutorbilt less than six months), as soon as I  could get out of the line of fire, a call to Mr. Clark was made and it was explained that he had obviously made a mistake.  Not only did they need the most capable person in the plant but they wanted to talk to a corporate officer as the mention of a lawsuit came up in every other sentence.  This was my first indication that Mr. Clark was a “sandbagger” of the first degree.  He knew what the problems were.  He just didn’t want me to know until I was in the fire up to my elbows.  He admonished me with, “If you want me to have some calling cards printed that says ‘vice-president’, I’ll do it and send them to you.  Meanwhile get back at it and take care of the problem.” 

Somewhere in the back of my mind was the remnant of marine engineering courses and psychometric charts.  A trip to the library in the evening brought me up to speed so that I could at least follow along in the conversation.  After some calculations were made the light dawned.  There were two conditions to be met; one called the “design” conditions and the other called the “overload” conditions.  We had tested at the overload conditions and assumed that if the units met that, we would have the design conditions “cold turkey,” so to speak.   Turns out the design conditions were much harder to meet, with the overload conditions put in just to insure that the units would physically function at the tarmac temperatures that existed in that tropical climate known as Tulsa, Oklahoma.  It took about three weeks before it was able to get the units to operate somewhere near specifications.  Refrigeration suction pressures were adjusted  to get the most out of the system.  Speeds of components were fine-tuned and finally Douglas Tulsa bought them off.  I was able to go home after a three week on the job training in refrigeration systems.

These were the last complete units built for this service by Sutorbilt.  After that they were content to vie for the bare blower business and let others more skilled in the refrigeration end, build the complete package.  Just about this time a third blower company was showing signs of being a competitor.  A Company that came to be known as the Mehiele-Dexter Company (Later to be known simply as MD Blowers) started competing for the aerospace business.  They built a blower that had three lobes instead of two.  While this cut down on the displacement of a given size, the thicker throat allowed them to operate at much higher speeds with the resulting smaller overall size.  Their price was right and those jobs were bought on price. Sutorbilt competed with them successfully in the early days but finally gave up the declining aerospace market to them.  This was helped along by the decision of the new owner, Fuller, to standardize on product lines and to build no special blowers.  The aerospace market was rife with specials and it wasn’t unusual to see blowers with shafts extended through the gear case to drive hydraulic pumps.  Special flanges to match the standard motor NEMA “C” faces were common.

Bulk Cement Trucks

MD Blowers weren’t taken seriously as a competitor until they tried to make inroads into the growing pneumatic bulk truck market.  Bulk feed trucks had started in the East and represented a good market for blowers.  A company called Sprout Waldron expanded their feed milling equipment by producing a bulk feed truck that would deliver feed from the miller to the farmer using the feed.  The trucks would blow the meal into small storage silos located at specified points around the farm.  Sutorbilt had adapted a model 7H for this application.  (They added an aluminum gear case as a token weight saver.)  Sprout Waldron would issue orders in the hundreds of blowers and they and the Middle Pennsylvania Sutorbilt Representative, were very happy with the arrangement.

When the bulk cement trucks started to appear, there were a myriad of designs.  Sutorbilt continued to offer the 7H blower, ala “Sprout Waldron”, for this new industry as well.  One of the considerations given to the truck size was weight.  One of the major haulers out of Wisconsin didn’t even carry a spare tire.  (Hell, the driver had to call an expert to change it anyway.)

The evolution of the design for a bulk cement truck is worth noting.  Fuller Company and Fruehauf Trailers went together to design a bulk cement truck.  After all, the Airslide railroad car was the standard in the industry.  Fruehauf sent an engineer to live at Fuller and while one supplied the pneumatic conveying expertise, the other would make the entire product roadworthy.  As they slaved away, there was another Fuller engineer who came up with an idea for a small-containerized product to hold and convey drilling mud to the burgeoning  off-shore drilling rig market.  This little jewel was called an “Airslide Pump” and when he took it to the powers that be at Fuller, they patted him on his head and said that it showed promise and that they would put it in the catalog.

Along came a fellow from Baton Rouge by the name of Tom Nix who just happened to see this design for the Airslide Pump.  Delta Tank, Tom Nix’s company was in the business of supplying equipment to the off shore drilling rigs as well as manufacturing low pressure propane trailers.  Stopping just long enough at Fuller Corporate to get a license to build portable and stationary Airslide Pumps, he returned to Baton Rouge with an idea.   He took one of his liquid propane trailers and welded an Airslide section in the bottom.  The Airslide Pump part of the design allowed the aeration air coming up through the belting to be collected and become the source for the conveying air.  The system was designed to operate under 15 PSIG to keep the trailer from being considered as a pressure vessel.  The secondary asset to this design was that a positive displacement blower  could operate up to that pressure.  In a two week period, Tom Nix introduced  to the cement world a brand new design of a bulk cement truck and the first order was for 150 trucks to this same Wisconsin Trucker that disdained the carrying of a spare tire so that weight could be saved.

Meanwhile, Sutorbilt, who had been supplying blowers to Delta Tank for their off shore drilling equipment, now found another application.  Every one of these trailers needed a blower.  Let’s trot out the 7H and make that a standard.  That baby weighed in at 435 pounds and after all, it had an aluminum gear case.  What more could a customer want?  A bit more it turned out.  Get rid of the spare tire.  Who wants to haul around a 435-pound dead weight that is only used for a half-hour or so at the destination to unload the cement.  Standing over to one side was MD Blowers, waving their arms and saying our product only weighs 285 pounds.  Where Roots created the speed race a few years before, MD started the weight reduction craze.  Before it was through, Sutorbilt built a new series blower (the 88 Series) that had lots of aluminum, very thin head plates and a whole lot of maintenance problems.

The Series 3000

Another series that came into being in the late 1950’s was the series 3000.  This was a group of blowers limited to one gear diameter, eight inch.  The need for this was created by the way Roots had designed their series.  Their small series was limited to a maximum of a seven-inch gear.  Eight inch and larger were built on the larger series design.  Sutorbilt’s small blower series went through eight-inch gear diameter.  Since the smaller series operated on a different set of design parameters, their eight large blowers would out perform the Sutorbilt eight-inch small blower design.  Sutorbilt’s answer was to add a new series to the line that would almost perform to the design capabilities of the large blowers.  (3000 FPM gear speed versus 3200 FPM gear speed.)  This proved to be a very popular machine as it was easier to build than the large units.  (It had no force feed lube pump and the timing gears were secured by the use of a set of “grip rings”.  This made for easy timing at the factory level but was a bit disconcerting to the non-pro out in the field.)

Pacific Pneumatics

Pacific Pneumatics started on a true shoestring.  Operating out of the house, it was a one- man sales force and a bedroom was designated as an office.  A couple of extra lines were brought in and telephones hung from the wall within easy reach. Principals were not easy to locate as they all had a certain reticence about signing on with a true unknown.  Finally enough signed on to make it a respectable list and we were off and running.  Before the year was out, we had Sutorbilt for the San Joaquin Valley and the Imperial Valley.  That pretty well covered the cotton seed industry except for one mill in Vernon.  Propellair Fans and Universal Silencer were the first to sign on, followed by Fuller Compressors, Lehigh Fans and Peterson Filters in ensuing years. 

From the beginning, fabrication played a part of the operation.  Sutorbilt had for many years fabricated anything to which they could tie a positive displacement blower.  Once they decided to concentrate on blowers only, they wanted to shift the fabrication of those special items to someone else, while selling the blower that would be the heart of the package.  The first Pacific Pneumatic sale was such an animal.  An inquiry came in for an oil tool sump cleanout unit from Hughes Aircraft.  They needed one just like one Sutorbilt had fabricated some years ago.  Sutorbilt even donated the shop drawings.  A local fabricator, Holzinger Bros. Sheet Metal, was found and the bid was made.  It was during this time that the use of a name rather than that of an individual was appreciated.  The purchasing agent, in his best buying pose, wanted to know how much we could cut the price to get an immediate order.  It took all the courage possible to stand pat and say, “I just sell these things, I don’t set the price.”  The buyer sighed and fished out a Purchase Order and Pacific Pneumatics had its first sale.    

Learning New Terms in the Rep Business

Moving from the world of positive displacement blowers into one where fans and compressors were involved meant learning new concepts and markets.  The business was built around the PD blowers but now things like “velocity pressures” and “static pressures” crept into the conversation as new customers and contacts were made for Propellair Fans.  Propellair was a division of Robbins and Meyers and manufactured a line of industrial ventilation equipment that included wall fans, powered roof ventilators and space heaters.  It was interesting to see how companies like Robbins and Meyers diversified in the “Olden Days.”  Robbins and Meyers was a manufacturer of electric motors.  Manufacturers of other products most often needed a motor to drive their equipment.  Many of these companies operated on short capital and needed generous credit terms to continue to operate.  It was a policy of Robbins and Meyers to give very generous terms to their customers.  This cemented relations that insured the continuance of that customer.  In many cases the cementing turned to concrete as the company, unable to pay their bills to R. & M., ended up being owned by them.  Thus Robbins and Meyers grew and prospered and insured that their line of specialty motors had built in customers.

Carpet Cleaning

It was about this time that a new application was appearing on the horizon.  Floor coverings were changing.  In the past the floors were mostly hardwood and the soft coverings were small to large rugs.  When the rugs needed cleaning they were picked up by a cleaner and hauled to a location where they would be scrubbed and vacuumed and then hung and stretched to dry.  Many of these rug-cleaning companies also cleaned and refurbished upholstered furniture.  In some of the more wealthy neighborhoods there was something new being put down on the floor, something called wall-to-wall carpeting.  In Southern California, there was a concentration of these homes in the areas serving Hollywood.  In 1947, a company called Truman Doyle, who had a large rug and upholstery cleaning business, saw a new application coming, that of cleaning carpeting.  They envisioned a company with a fleet of trucks that would travel and clean carpets on site.  They came to Sutorbilt looking for a blower to build into a lightweight portable cleaner.  The finished product was something called a “V2" rocket, named after a missile of World War II, and which was enclosed in surplus airplane parts, giving it a somewhat futuristic look.  The unit directed the flow of air entrained liquid into an area covered by a clear plexi-glass enclosure and their motto was “See the dirt boil out.”  They built a number of these units but did not take it outside of their own company’s use.  

By 1963 the business had grown to where the “office in a bedroom” would no longer suffice and an industrial location was found in Santa Fe Springs

Packaging of Blowers

Fabrication of packages was now a larger part of the business.  The company had sort of backed into the business by the policies of Sutorbilt.  They had gone on a standardization binge which included the packaging of blowers.  There were some 35-40 sizes of small blowers using motors up to 50 HP.  In their efforts to reduce the number of assembly sizes it was decided to build only three size bases. One such unit was sold to a local customer.  When it was delivered, he called and asked that someone come out.  Pointing to a base that took up a large area and on which was mounted a small 2L and a 1 HP motor, he wanted to know who was going to pay his rent on the excess area covered by the large base.  In an effort to mollify the customer it was decided to return the unit to Pacific Pneumatics and repackage it into a more space saving arrangement.  Thus a business began that was to become a major part of their operation.  Once again, Holzinger Bros. Sheet Metal came to the rescue and did the repackaging.  As time went on, the packaging was done in-house as Pacific Pneumatics grew into a full packaging and fabricating facility. 

Sutorbilt blowers formed the heart of Pacific Pneumatics for most of its early life.  As the fabrication of what was to be called “Engineered Products” increased, more blowers were bought outright rather than sold directly to the user with the billing by the factory. As the OEM business for carpet cleaner blowers increased there was a move to have sufficient stock for their needs.  Thus it was deemed proper to have Sutorbilt supply Pacific Pneumatics with consigned stock.  While this was going on Pacific Pneumatics moved locations twice, both within a few hundred yards of the first location on Marquardt in Santa Fe Springs.  To hold the stock of blowers, large welded steel racks were built and the offices expanded to hold the growing force of office and sales persons. 

The Powder Pump

In the early sixties, work was done with Great Lakes Carbon Company and Gorman Rupp Company to develop a better method of conveying diatomaceous earth.  Great Lakes Carbon was one of the truly great privately owned companies.  Their method of doing business not only extended to customer satisfaction, but to the protection as well.  If your bid to them was low by any large percent, they would call you and let you check your prices before they gave you an order.  Their headquarters was in Chicago and they were owned by the Skakel family.  (One of the more prominent names out of that family was Ethel Kennedy.)  They had diatomaceous earth plants at Walteria and Lompoc in California and a perlite plant near Soccoro, New Mexico.  All these plants had trouble handling these very abrasive but very light weight products.     

  It was found that a diaphragm operated liquid pump could pump these products if modified and if the product was aerated.  Gorman Rupp had the diaphragm pumps; Pacific Pneumatics had the aeration knowledge; Great Lakes Carbon had the product to be conveyed.  A number of designs were tested and one was found to be satisfactory.  Now came a dilemma for the other companies.  Gorman Rupp was only interested in building a product that had a volume production possibility.  This application was interesting but not one that was going to built in volume.  Great Lakes Carbon was not interested in the machinery business.  Thus it defaulted to Pacific Pneumatics to build the package out of components supplied in part by Gorman Rupp and to customers mostly supplied by Great Lakes Carbon. (During this time the Mining, Mineral and Pigments Division was spun off and sold to General Refractories and became known as Grefco and any further references will be to Grefco.)  The Walteria plant at the bottom of the Palos Verde Hills was closed as the earth was more valuable as real estate than as a filter aid.  I believe the Real Estate people call it, location, location, location.

As time went on the customer relations engineer at Grefco (In the early days was Howard Baker) would visit a customer and tell them they needed a powder pump manufactured by Pacific Pneumatics.  The price was so and so; call them with an order. We would ship the unit; Howard Baker would trouble shoot the installation and this product was a profitable though somewhat limited in its sales.  (Somewhere along the line someone noticed the “PP” connection of “Pacific Pneumatics” and “Powder Pumps” and this naming of products continued through “Pore Poly” and “Posit Pulse” Filters.

The Powder Pump was used in many other applications but always had some maintenance problems associated with the learning of how it operated.  Other companies offered their air driven diaphragm pumps to the industry, but with out any guarantees of performance.  Their price was so attractive that the customer would buy, hoping that the pump could be used in some liquid application if it didn’t pump the powder.  Thus Pacific Pneumatics was limited to those customers who wanted an engineered product.  Over the years, the units have been supplied in limited quantities over the world. 

In Summary

We will leave this story of the positive displacement blowers in the late 1970’s, as this is a story of some of the early days of the positive displacement blower industry as seen through the eyes of one Mark Royston.  Some of it is factual, a large part fancy.  It can be a testimony to the fact that the Roystons have seen a lot of positive displacement blowers sail down the river of industrial progress and that some of this knowledge is being transferred into this Web Site.  Don’t read it for fact, read it for enjoyment.


 By: Mark W. Royston
La Mirada, California

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