About Us:


In 1990, Charles Ekstam began research that led to the development of the first and only Fuel Air Separation System for diesel engines.  On March 15, 1993, the first system was sold. It was trademarked Fuel Preporator®.


Over the course of the next 20+ years, the Fuel Preporator® as well as the company, went through several iterations. Fuel Preporator® models have been developed for virtually every diesel engine application, including:



                Commercial Trucking

•       Excavation & Mining




                Pick-Up Trucks


In 2002, the AirDog® trademark was coined for the pick-up truck system. With the intense popularity of the trademark, it is now used on all of PureFlow's Fuel Air Separation Systems. The Raptor® trademark followed shortly thereafter for the pick-up truck fuel pump line. 


Additionally, the new 4G-HD Industrial Pump product line will fall under the umbrella of the AirDog® trademark.

In the fall of 2009, W.A.P. of Shelbyville, Indiana, entered into a non-exclusive Manufacturing and Sales Agreement with PureFlow® Technologies and an Intellectual Property License Agreement with Charles Ekstam, the Inventor. W.A.P. formed PureFlow AirDog®, Inc., and now manufactures and markets the AirDog® and Raptor® product line for pick-up trucks under the corporate name of PureFlow AirDog®.


Fast-forward to present day, and PureFlow® Technologies, Inc., in their 33,500 square foot manufacturing facility and employing a strong network of strategic partners, produces the highest-quality product line of fuel air separation systems and fuel pumps, shipping to distributors and dealers throughout the United States and beyond!




   CANADA                 UNITED STATES OF AMERICA                     MEXICO 

2,108,391             5,355,860; 5,746,184; 6,729,310                270409


 NEW ZEALAND        ITAL Y           AUSTRALIA          CHINA               ECUADOR

       532356          1362177       2008212010     1061420         PL 10-2021


Additional Foreign Patents Issued and Pending! 


PureFlow® Technologies, Inc.

5508 Business 50 West

Jefferson City, MO 65109

Toll Free:1.877.GO DIESEL


Direct: 1.573.635.0555

Fax:     1.573.635.0778



Hours of Operation


8:00 AM-4:30 PM

Saturday & Sunday



8 PG AirDog Commercial Brochure 2013.pdf
Adobe Acrobat document [1.0 MB]
12 PG AirDog Marine Brochure 2012 with [...]
Adobe Acrobat document [1.3 MB]


How Does Air Become Entrained In Diesel Fuel?


As in all liquids, air becomes entrained in diesel fuel from sloshing and agitation! Air can be on the surface of the fuel in the form of foam or it can be in the bulk fluid in the form of tiny bubbles. Entrained Air is an issue of an "in use" engine in operating equipment!


What is Pump Cavitation?


Pump cavitation, simply put, is the pump not having enough pressure flow, or "Net Positive Pressure Head" of fuel coming into the inlet to completely fill the vacuum chamber of the pump.


Diesel fuel, as is true with all petroleum base liquids, will give off vapor when subjected to a vacuum. The amount of vapor depends upon the level of vacuum and temperature.


How Does Fuel Filter "Restriction" Effect Cavitation?

In the diesel engine industry, "fuel filter restriction" is a term that refers to the vacuum level at the inlet to the transfer or lift pump. It is measured in inches of mercury (in hg).


As the filter plugs with use, it further restricts the flow and increases the vacuum level in the pump.


The amount of vapor produced depends upon the level of vacuum.


What Else Increases Cavitation and Vapor? 


As the fuel levels in the tank(s) goes down as the fuel is burned, the "Dry Suction Lift" increases. This reduces the flow, increasing the vacuum.  


Operating at higher altitudes, where atmospheric pressure is less, reduces the fuel flow and increases vacuum. For example, at Denver,  atmospheric pressure  is about 17% less than at sea level and at Eisenhower Tunnel, it is approximately 32% less. Having less pressure to drive the fuel from the tank to the transfer pump, reduces the flow and increases the vacuum levels.


Higher fuel temperatures cause more vapor to form than cooler fuel under the same vacuum!