In college I never thought I’d someday get involved with homogenizers, never-mind a homogenizer called a Sonolator! Sure, I figured valves, pumps, flow meters, etc. This was standard fare for process engineering after all. Homogenizers are a bit trickier and less well known. Wikipedia defines them as such:
A homogenizer is a piece of laboratory or industrial equipment used for the homogenization of various types of material, such as tissue, plant, food, soil, and many others.” Homogenization being any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout. This is achieved by turning one of the liquids into a state consisting of extremely small particles distributed uniformly throughout the other liquid.
In 1991 I left college and moved outside Stratford, CT to work at Sonic Corp, a small manufacturing and engineering firm specializing in customized homogenization systems. Their flagship product was the Sonolator Homogenizer, an in-line, ultrasonic, high-pressure device that was coupled to a PD pump to emulsify and disperse a variety of fluids. The higher ups within the small company explained that it was modeled after a century-old device known as a Pohlman Liquid Whistle. This device, and others, were featured in an article by a Charles O. Morris who had presented to the wood industry various means of processing paper pulp slurries. The main thrust of the article was that ultrasonic energy generated by Liquid Whistles, as well as various piezoelectric probes, serves to emulsify, homogenize and disperse all manner of liquids. Here’s what Morris says about liquids and ultrasonic energy:
The Pohlman Whistle could generate this ultrasonic energy by directing a liquid stream at high velocity over a blade-like reed set in the liquid path. Pressure oscillations and cavitation are formed creating violent disruptions within the liquid which break down particle sizes. This is an early illustration of the Pohlman Whistle device:
Folks here at Sonic also spoke of an Eric Cottell, a British inventor who had taken this Pohlman concept and patented a device he would long-windedly refer to as an “apparatus for the mechanical production of acoustic vibrations for use in emulsification, dispersion or like processes.” Here’s an image of Cottell’s 1952 invention:
It might be hard to discern, but you can see that fluid enters from the left, funnels down to a narrow slit, then projects out at high velocity into the knife-like blade (item 11). This device was actually attached to the end of a hose and placed within a process fluid tank and recirculated by means of a pump.
At the time, these single-feed systems were used for dispersing fumed silica into resin or processing silicone emulsions. Dow Corning and DuPont standardized on the Sonolator in the 70’s for processing many of their emulsions in the silicone and textile businesses.
In its modern day rendering, the Sonolator (see movie) uses the same basic principles of ultrasonic energy and cavitation to mix, emulsify and disperse. High flow versions can achieve 100-150 GPM at pressures to 500 PSI, 1,000 PSI and 5,000 PSI.
The Sonolator itself features a specially machined Orifice that is removable and replaceable. The knife-like Blade is prominently featured still but is no longer designed to vibrate. Modern theory now suggests that the oscillations of the fluid passing over the Blade and the cavitation that is generated is more effective than trying to generate ultrasonic energy waves by vibrating the Blade within the liquid stream. This makes sense given that the chamber where the Blade resides is not fully flooded due to the high velocity of the liquid stream at that point.
Modern advancements in pump technology have allowed us to couple the Sonolator to a variety of PD pumps and fabricate in-line systems where recirculation is not required. Sonic Corp has grown along the way as well adapting the ability to conceive, design, 3D model and fabricate complete Sonolator homogenizing systems. We’ve developed the only true high-pressure, multiple-feed homogenizer systems available from a single source. We do this by using several different PD pumps with mass flow meters and metering these streams into the Sonolator inlet. You can meter hot oil phases with ambient water phases and create an instant emulsion via the Sonolator’s high-pressure ultrasonic energy chamber. Here’s a fully integrated system:
The Sonolator is buried in there as the heart and soul of a complete system that meters various streams and homogenizes on a continuous basis. Moving from large, bulky batch tanks to this streamline process saves considerable time, money and resources.
The Sonolator as you see has come a long way from it’s first inception at the turn of the century as a Pohlman Whistle. Thanks to the inventiveness of Eric Cottell and others, including myself, here at Sonic who have modified the theme over numerous decades, the Sonolator Homogenizer is doing well. We still find after years of research that the Orifice-Blade method of generating pressure, cavitation and ultrasonic energy is superior to conventional homogenizer valves that use spring loaded impact valves.
As for me, I’m comfortable in my new role as the sole owner of this unique technology. I continue to be intrigued by the various forces at work that seem to make the Sonolator work so well. We continue to explore ways to enhance the ultrasonic energy and cavitation within the Sonolator by modifying Orifice geometry and Blade design.