As touched upon earlier, the pump-to-orifice pressure is the dictating force when generating fine emulsions and
dispersions and is determined by either the flow rate generated by the pump or the size of the orifice through which
the material flows. The intensity of the mixing or dispersion that occurs within the Sonolator is a direct function of
the pump-to-orifice pressure. The cavitation levels achieved will vary directly
with the pressure; the blade-to-orifice
adjustment and the back pressure tuning valve are used to enhance cavitation. A low pump-to-orifice pressure will
thus generate low cavitation levels, and a high pump-to-orifice pressure will create higher levels. Every product has
a specific pressure at which it is most effectively homogenized, and once that pressure is determined, efforts should
be made to insure that that specific pressure is maintained while generating product. For production units, that
pressure is pre-determined either through lab tests conducted at Sonic or from research performed on a Sonic rental
unit at the customer's plant. Given the desired production rates and the predetermined pressure, Sonic calculates
the orifice area which yields the desired pressure at the desired flow rate.
Orifice Calculation:
The relationship between orifice area, pressure, and flow is expressed with the formula:
QA= 30 P
where: Q = Gallons per minute throughput of a water-like material, at the
desired pressure (PSI) as approximated from pump curves.
A = The area of the orifice, in square inches, as
marked on the face of the orifice.
P = Desired pump-to-orifice pressure, in PSI.
30 or K = Viscosity and pump slip constant
Converting this equation allows one to calculate the required orifice area given the flow and the pressure:
AQ P= /30
Generally, the pressure at which a production system operates does not need to be altered. If, however, a company
needs to change the operating pressure, uses a Sonic lab unit, or is running various products that are emulsified or
dispersed at different pressures,
The Pump-to-Orifice Pressure May Be Varied Two Ways:
(A) The speed of the pump may be adjusted on some units which utilize the variable speed drive arrangement.
Accelerating the pump speed will increase the pressure.
(B) A new orifice with a different area may be installed. The area of the orifice directly determines pump-to-orifice
pressure when the speed of the pump and the viscosity of the liquid are maintained constant. Orifices with smaller
areas will generate higher pressures.
Warning!
: Do not alter the pressure by toggling either the back pressure tuning valve or the blade-to-orifice
distance. When the pump speed or orifice is changed, the Sonolator may need to be re-tuned.
Troubleshooting Pressure Problems
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