S. Berliner, III's sbiii.com Pall HIPS Page keywords = HIPS Hyper Intense Proximal Scanning Ultrasonic Filter Element Cleaner Pall Corporation Aircraft Porous Media filtration medium Trinity Micro Rigimesh bubble point PSS differential pressure Cavitron Lipari Ranch Model Dutka Hydra-Tec Heat Systems AC-2858-1

Updated:   21 May 2014; 08:00  ET
[Page created 23 May 2011 but first posted 30 Apr 2012;

    original AT&T Worldnet Website begun 30 May 1996.]
URL:  http://sbiii.com/pallhips.html

S. Berliner, III
Consultant in Ultrasonic Processing
"changing materials with high-intensity sound"

[consultation is on a fee basis]

Technical and Historical Writer, Oral Historian
Popularizer of Science and Technology
Rail, Auto, Air, Ordnance, and Model Enthusiast
Light-weight Linguist, Lay Minister, and Putative Philosopher

note-rt - The vast bulk of my massive Web presence (over 485 pages) had been hosted by AT&T's WorldNet service since 30 May 1996; they dropped WorldNet effective 31 Mar 2010 and I have been scrambling to transfer everything.  Everything's saved but all the links have to be changed, mostly by hand.  See my sbiii.com Transfer Page for any updates on this tedious process.

S. Berliner, III's


Pall HIPS Page

{preliminary release}



[Hyper Intense Proximal Scanning Ultrasonic Filter Element Cleaner]

note-rt   DISCLAIMER - This private page is intended solely to relate the history of a particular device developed and manufactured (originally) by Pall Corporation and is not to be taken in any way to represent an official page or site of that business entity.

Once upon a time, long, long ago (during World War II to be a wee bit more exact), a young Canadian-born chemist from Montréal, Dr. David B(oris). Pall by name, developed a sintered (sinter-bonded) powdered stainless steel filter medium for the Manhattan Project to help separate U235 from U238.  It offered several notable advantages over paper or cloth filters.  First and foremost, it could withstand very high temperatures.  In addition, it could withstand very high differential pressures, especially when backed by a heavy mesh supporting structure.  It also could have quite small pore size and could hold that pore size fairly consistently.

Sintering entails laying down an ultrafine stainless powder in an inert atmosphere, raising its temperature to just under the melting point of the stainless steel (around 2,550-2,64 °F/1,400-1,450°C), at which temperature the surface molecules are excited just enough for adjoining particles to melt together without the particles (spheres) losing their shape.  Thus, the voids between the spheres are mantained essentially open and a porous yet rigid material results.  This, then, provides an amazing fluid filtration medium.  Further, the material could be cleaned and reused almost indefinitely.

In 1946, after the war, Dr.Pall formed a company to market his development, Micro Metallic Corporation, and trademarked the material as PSS™ Porous Stainless Steel.

The downside of PSS was that the pore size was not quite as uniform as might have been desired and there was always the possibility, no matter how slight, that particles on the downstream surface might be dislodged and pass into the very product or machinery the filter was supposed to protect.

Accordingly, ca. 1955, Dr. Pall had the brilliant idea of sintering woven stainless steel wire mesh instead of powder {more to follow}.

In 1957, the company was renamed Pall Corporation, with Micro Metallic becoming a subsidiary, one of the Pall Filtration Companies.  About this time, the new sintered mesh was trademarked as RIGIMESH® sintered wire mesh and almost instantly became a big hit with the airline industry and then the military.  Well, it's great to have ultrafine reusable filters but you need a reliable way to clean them; dunking and sloshing in detergent or solvent might be fine for automobile filters but they just would't do for fine stainless reusables.  Ultrasonic cleaners (baths) were just the ticket but they didn't have the intensity to dislodge particulates embedded in the mesh at high pressures.  Accordingly, Pall turned to a manufacturer of high-intensity ultrasonic probes, Cavitron Corporation in nearby Long Island City; Cavitron was becoming famous for its dental prophylaxis unit (later made by Dentsply) and the Cavitron-Kelman phæcoemulsifier for removing cataracts.  Under the able ægis of design engineer Charles Lipari, Cavitron came up with a machine that combined Pall's requirements for the functions of a high-intensity cleaner, a pore-size determinator, and a flow capacity tester.  Pall's alter ego was brilliant engineer Robert I. (Bob) Gross, assisted by yours truly.  The project later was handled by Lab Director Erwin Kirnbauer and lastly devolved solely to me, whereupon I developed a completely redesigned model which was built by Pall (subcontracted to Sey Dutka's Hydra-Tec), with a simplified design of probe/transducer and solid state generator from Cavitron.

Named (mercifully briefly) the HIPSUFEC (Hyper Intense Proximal Scanning Ultrasonic Filter Element Cleaner - really!), it quickly became known as the HIPS™ Ultrasonic Filter Element Cleaner.  Airlines were the major customer, followed by the U. S. military (USAF and USN for aircraft and USN for submarines).

Cleaning was accomplished by placing a wetted filter element longitudinally under a ½" x 2½" (12.7mm x 63.5mm) blade oscillating at 20KHz (20,000 cycles/second) at a peak-to-peak (double) amplitude of 0.0014" (36μm).  Most aerospace filter elements were of corrugated (pleated) form and the high amplitude served to drive cavitational energy deep into the corrugations.  Cleaning fluid was driven outward (backwashing) through the mesh, "blowing" the contaminants off the medium and into the tank from whence it was captured in disposable ultrafine filters.  The filter element was rotated by hand to get full coverage and larger elements were also translated longitudinally (again manually).

After cleaning, a brief cleaning was done with flow in the normal direction to wash any contaminants out/off of the downstream face and the maximum pore size determination was done by a Bubble Point Test to assure reusability.

The blade/tool/horn was driven by a magnetostrictive stack of nickel laminations, very reliable and powerful but also very inefficient, generating a lot of heat and requiring (in its first incarnation) a dual air- and water-cooling system.  Output was monitored by an ingenious arrangement whereby a nickel pin was brazed into the back end of the blade (horn) and its elongation and contraction as the blade oscillated was sensed by a magnetic coil surrounding the pin.

PHOTOS   restored (10 Mar 2014}:

[All photos and diagrams from 1969 and 1970 Pall literature.]

Here is the original model HIPS, AC-2858-1, with a tube-type power supply and a water-jacketed convertor (transducer):

This is my elaborate systems schematic (replete with a radio tube!), redrawn professionally back then for publication.

This transducer schematic shows the dual cooling provisions - outer annulus "A" is air cooled, forced by the big blower,
while inner annulus "B" is water cooled.  Also shown is the amplitude pickup coil and pin.

A general view of the working area, with the ingenious mechanical amplitude meter mounted in front of and
under the blade.

If I recall aright [and it's been 53 years!], the grinning gentleman is/was James (Jimmy) Lodato, trying manfully not to burst out laughing (the tank is empty for photography!).
He's holding an AC-930E-11 hydraulic filter element from the Lockheed L-188 Electra/P-3 Orion aircaft.

In this view, the filter element mounted is the big AR-1256E-311, which was the main fuel filter for the Electra/Orion.  The bubble point line is draped across the counter and the dull-looking (anodized aluminum) adaptors are for bubble point testing.  The bright, shiny stainless adaptors are for cleaning and flow testing and you can see the differential pressure probes mounted axially in the center of them.

In this detail shot, you can see the ingenious mechanical amplitude meter mounted in front of and under the blade and, through the access port above that, the sensing coil on the back surface of the blade, with the nickel sensing pin barely showing through it's upper end.  At lower left is the open end of a cleaning adaptor with it's axially-mounted differential pressure probe.

So, not only did we have a big electric fan blowing air in a hydrocarbon-laden atmosphere, we also had high-voltage input power to the transducer coil in a water bath!

Filter elements with longer media than the 2½" (63.5mm) width of the blade had to be slid axially in and out on the adaptor (mandrel) to assure full coverage.

For our next trick (my version), we (courtesy of Cavitron) switched to a solid-state power supply (generator) and an air-cooled transducer (no more water);  We also redesigned the unit to have a longer tank with the transducer assembly mounted on a sliding track so the blade could be traversed along the surface of a long filter element.

Although the control panel layout had to be drastically revised, that second model, AC-2858-1X, was largely otherwise unchanged but we at Pall built it ourselves (subcontracted to Sey Dutka's Hydra-Tec firm), with only the electronics and the transducer assembly coming from Cavitron:

HIPS-AC2858-1X HIPS-AC2858-1Xa

A third model was built in very limited numbers; it was dubbed the Ranch Model because it was "L" shaped, with an elongated tank at right angles to the console, allowing cleaning and testing of even-longer fluid filter elements (I don't seem to have pictures or specifications for that version).

Esso VARSOL™ (varnish solvent) is/was better known as Mineral Spirits and we bought it by the 55-gallon (208l) drum from Mattiace Petrochemicals, also in Glen Cove.  I all-too-well remember the last small purchase we made; I went over with a gallon jug and the young man who filled it must have dumped another gallon onto the ground in the process.  Many years later, Mattiace was cited for pollution and their lot was condemned as a brownfield.

[An odd aside - Charlie Lipari left Cavitron to form his own firm, Electromation Components Corporation (EMC), making ultrasonic devices for general sale and electonic controls (for Pall).  Not coincidentally, I left Pall Corporation to work with him.  At that juncture, EMC was bought by Radiation Applications, Inc. (RAI).  After the sale, RAI's pencil-pushers decided in their great wisdom that EMC wasn't making enough profit and I was directed to double my prices; the market wouldn't bear the increase and that was that for my big career move!  A few years later, Pall Corp. bought RAI and Charlie became the head honcho of Pall-RAI and a VP of Pall!]

There was briefly a "third generation" HIPS machine, which I built many years later (ca. 1980?) at Heat Systems for some foreign airlines with Sey Dutka's Hydra-Tec but utilizing "my own" piezo-electric transducer and generator from Heat Systems' SONICATOR processor, driving a titanium ½" x 2½" (12.7mm x 63.5mm) horn (blade).


  What happens to all this when I DIE or (heaven forfend!) lose interest?  See LEGACY.


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