Self-purging liquid filter unveiled
03/01/2002
The inventor of Tang and the Selectric ball aims to make his mark in contamination control
Mark A. DeSorbo
LAS VEGAS—A walk inside Alvin A. Snaper's head would most likely reveal the secrets behind the IBM Selectric typewriter ball, the NASA Apollo Photo-Pack and Tang, among other things.
In fact, the Selectric ball, the NASA photo pack and the orange-flavored drink are just three inventions the 72-year-old has on a curriculum vitae of more than 600 patents for developments he's conceived for such clients as The Gillette Co. (Boston), Boeing Aircraft Corp. (Chicago) and General Motors Corp. (Flint, MI).
"I'm a crackpot inventor," Snaper says, with a dry wit. "I get into a lot of different technologies."
Contamination control is the next market ready to welcome one of Snaper's inventions; a self-purging, in-line filter for liquid streams like cleanroom de-ionized water systems.
"The device is not much bigger than the process pipe, and it is more compact than conventional filters and you don't have to shut the process down to replace a filter," he adds.
Outfitted inside a process pipe, the ceramic filter extends across the flow area and acts as an ultrasonic transducer, which vibrates and dislodges particles from the surface of the filter, Snaper explains.
 Alvin A. Snaper |
"Vibrations are five-millionths of an inch, and that creates tremendous pressures," he adds.
According to the patent, which was granted to Snaper in June 2001, a rib attached to the inside wall of the process pipe provides a laminar swirl to the outer boundary of the liquid stream so that a part of the swirl sweeps across the filter surface. A sump valve opens into the pipe upstream from the front of the filter. It opens periodically, while the filter is triggered to remove particle-laden liquid and discharge it into a sump.
"By using fluidic principals, we create at the surface of the filter a laminar flow which will sweep the particle-rich surface," Snaper says. "Normally, a ceramic filter is taken out of the unit, and then taken to another room where it is put into an ultrasonic solution. The ceramic sub-micron filter is also the ultrasonic transducer, and that makes it compact, less expensive and more reliable."
In addition, pores in the filter retain particles of specific sizes, and should there be a drop in fluid pressure caused by clogged pores, the power supply and sump valve are triggered, causing the filter to purge.
"I like to call it an active, intelligent, self-monitoring filter because it is sensitive to pressure drops, which can indicate that the filter might be clogged and the pores need to be cleaned," Snaper says, adding that particulate matter removed in a cleaning cycle goes into a closed system that can be removed in a cleanroom without contaminating the environment.
The filter, he says, can fit numerous applications, from water to solvents to fluids. Liquid viscosity, Snaper explains, is not important as long as there is ample power to push it through. That means the device can be used in cleanrooms as a pre-filter for DI water, process chemicals or coolants. "It can also be used to flush the particles from etches in the etching process," Snaper says.
Originally, the filter was designed three years ago for the Navy to filter diesel fuels in its ships. Although he did not get the Navy contract, Snaper followed through with the invention and obtained the patent.
"I do not necessarily know the ideal applications for these inventions," Snaper adds.
"Normally, when people hear my developments, they will know their business well enough to know how my inventions can work for them."
His underlying goal, however, is to outpace Thomas Edison, who patented more than 1,000 inventions, including the phonograph and the light bulb, says friend and partner Dr. Stanley Moulden, a member of the New York Academy of Sciences and recognized as a world community leader who has been recognized by Queen Elizabeth II as a world community leader.
"He is probably one of the most prolific inventors in the United States," says Moulden, an entrepreneur who founded Newton College in Lima, Peru. "His goal is to overtake the number of patents that Edison has. Snaper wants to out do him. He is a brilliant man, an inter-disciplinarian, who is very intuitive. We've been partners for more than 20 years, and he does not suffer at all from tunnel vision."
Snaper, however, is forever modest. He describes his discovery of the powdered orange drink, Tang, as almost a fluke.
As a chemist for General Foods in the 1950s, he was charged with coming up with a better way of disposing pulp and peels left over from orange juice processing.
"It used to be sewage, but I made it into a powdered orange drink that they fed to astronauts," Snaper says. "I analyzed it and found the necessary carotenes to make the powder."
Tang indeed soared in popularity throughout the world. "Now there's lemon-and cherry-flavored Tang. I have a collection," Snaper says, adding that there's a mix flavored with the sweet turnip-shaped jicama root vegetable. "They called me years later wondering how they could get more pulp and peels. I told them to grow more oranges."
Some of Snaper's other inventions include an implantable pedia-cardia heart pump; ultrasonic product lines for Aerojet-General Corp. (Sacremento); a coating process for razor blades using precious metals for Gillette; electrostatic painting and process for automobile components, General Motors Corp. and photo resist formulation for printed circuit manufacturing, McGraw Colorgraphic Co. (Columbus, OH).
Lately, his work centers on battery concepts that are expected to make electric automobiles more practical.
Snaper's Power Technology Inc. (Las Vegas), the company exploring new stored power methods, is made up of a team of a chemist, scientist and retired engineers in their 70s and 80s. Their creation is a foam structure that Snaper believes will take a standard lead-acid battery, reduce the lead content by 90 percent, and make it twice as powerful, half the size, environmentally-friendly and cost-effective.
"I'm having a lot of fun," Snaper adds, "so I don't call it work."