Typically they offer accuracy in the region of ±1%, but one company has been quietly manufacturing its own unique design of metering pumps that raises the bar to completely new levels of accuracy and control.
As long ago as 1983, after years of research and development, Fuji Techno Industries, of Japan, launched a range of innovative Super Metering Pumps (SMPs) that significantly improve performance, with astonishing pumping accuracy of ±0.1% or less! Not only that, but because of their unique design, they produce no pulsations in the flow of liquid.
According to Andrew Fallows, managing director of Motor Technology, the UK based European agents for Fuji Techno, no other pump in the world is able to match the accuracy and performance of the SMP. According to Fallows, for those applications and processes that require this ultra-high level of accuracy and control, the SMPs are quite literally in a class of their own.
Fuji's Super Metering Pumps are made up of a pump head, an electric motor and a triple plunger system driven by a specially designed cam that controls the motion cycle of the plungers. The liquid being pumped enters and exits the pump head through suction and discharge valves, filling each of the three chambers with a precise volume of liquid as each piston, or plunger, withdraws on its suction stroke. The liquid is then discharged as each plunger re-enters its chamber.
The three plungers work in perfect equilibrium with each other. The timing of each plunger's suction and discharge cycle being precisely controlled by the cam, so that the total liquid discharged from the pump is highly accurate and constant with no pulsations in the flow.
The plungers are designed to make different motions in six stages within one revolution of the cam and in harmony with each other. For example, the first plunger starts its discharge stroke with the cam at 0 degrees, the second plunger starts at 120 degrees, and the third at 240. It is this unique operation that ensures constant flow with no pulsations.
Specially designed suction and discharge valves result in smooth movement of the check balls minimising wear to the valve seats. This ensures high accuracy is maintained over long periods of operation, and eliminates the possibility of the valves themselves causing pulsations or leakage.
Typical applications include pharmaceutical and chemical processing, urethane and other resins, chromatography, explosives, food processing, film, spraying and coating applications, cosmetics line mixing for liquids, feed for extruders and water treatment.