Ofelft Family/Hypressure Jenny Invention

Whiskey stills and the birth of an industry!


A family of Pioneers in


Steam Engineering




Ofeldt’s Still:   “It was sometime in 1926 when Frank W. Ofeldt II, an employee of a western Pennsylvania producer of gas-fired water heaters and boilers, made his breakthrough. Ofeldt was busy piddling in his home’s garage, perfecting his design of a portable whiskey still for a local moonshiner, when he noticed an unusual phenomenon.”


“The Hypressure Jenny was the first Steam Cleaner ever made – first in the world! It was invented by Mr. Frank W. Ofeldt, II in 1927. He immediately joined Homestead Valve Manufacturing Co. in Coraopolis Pennsylvania, and later became Chief Engineer of the Hypressure Jenny Division.


“But Hypressure Jenny’s background dates back through three generations, to the invention in 1885 of the first gasoline-propelled motor-boat by F. W. Ofeldt. I, grandfather of the present Frank W. Ofeldt. This first motor-boat, or “Naphtha-Launch” as it was then called, was driven by a gasoline vapor generator similar in construction to the generator used in Hypressure Jenny for generating a cleaning spray.”






“In the 1880s Frank Ofeldt invented a small engine powered by a petroleum by-product called naphtha, which proved to be a very useful means of water transport when attached to 16 or 18-foot launches. For a while, these naphtha launches flourished on the Adirondack lakes, transporting passengers and freight between camps, hotels and settlements.” 


From the article published on Friday, December 24, 2010 by Anthony F. Hall, “Boating Before Gasoline: Kenneth Durant and the Naptha Launch.






Do you know of other Inventors or Inventions that came out of Moon Township like the Ofelts or Hypressure Steam Cleaner?


Be sure to let us know, so that we can document our history for future generations!


Check out this website to see early uses of the Jenny Steam Cleaner, including the cleaning of the Statue of Liberty!




The Ofeldt Family


Frank W. Ofeldt II, was a resident on Moon Township about 1927.  In that year he invented the Hypressure  Jenny, which was the first steam cleaner ever made.


He immediately joined Homestead Valve Manufacturing in Coraopolis and later became Chief Engineer of the Hypressure Jenny Division.  Today the cleaning Jenny is still produced by Jenny Products, Inc., in Somerset, Pa.


The Ofeldt family had an interesting history in steam products.  By the 1880’s, steam engines were well established for steam launches and larger boats.  However, steam explosions, normally with disastrous results, caused a law to be written that any marine vessel with a steam engine must have an engineer on board.  This law made steam power impractical for small launches.


Frank W. Ofeldt I, the grandfather of our Moon resident,  built the first United States  “Naptha-Launch” boat to get around this requirement. He used naphtha rather than water to generate vapor.


Naphtha, a petroleum distillate (think of a crude gasoline) had a much lower vaporization pressure, so was assumed to be safer.  And records indicate it probably was.


Many Naptha-Launches were produced in Brooklyn.  They were a pleasure craft for the well-to-do, averaging about 24 feet in length.


Their selling slogan:  “Every Man his Own Engineer”  was cleverly worded because of the law.


The Naptha engine preceded the internal combustion engine.  In 1899, Ernest F. Ofeldt fitted one of his Naptha engines to a carriage. The water tank carried 15 gallons, the fuel tank 5 gallons and it could go 20 miles.


The second Ofeldt car was a surrey with a fringe on top.  As Ernest Ofeldt explained much later,   “We wanted to have a car look as much like a horse drawn vehicle so that it didn’t scare the horses.”


In the picture are A.W. Ofeldt and  F.W. Ofeldt in the front seat in a  New York City parade.


Thanks to:   John Kennedy, Moon historian and past Jenny operator