Today, modern electronics and precision mechanics enable the miniaturization of many everyday and professional components. The Gerotor micro-pumps used in fluid transport are a successful example of this. Their simple, valveless construction allows compact dimensions for almost pulsation-free, easily adjustable output flow. Faulhaber's electronically commutated DC-Micromotors are ideally suited to drive these fluid handling machines. With their compact dimensions, they offer high power density and a wide speed range for excellent dynamics. As a result, flow rates can be precisely controlled, from the smallest volumes to constant maximum flows.
Precise delivery, high performance
There are many areas in which small quantities of liquid need to be precisely dosed. If long-term operation and seamless construction are also required, state-of-the-art technology is called for. Applications include the transport of crystallizable, light-sensitive or gas-emitting substances, as well as fuel cells, the transport of urea solution (AdBlue) for the denitrification of off-gases in diesel engines, and dialysis and analysis technology. The hermetically sealed pump head is driven by a robust rare-earth magnetic clutch, which prevents leakage on the drive side. In combination with the materials available, such as nickel-based carbide, stainless steels, ceramics based on aluminum or zirconium oxide, silicon carbide or plastics such as PTFE, PEEK and FKM, the pumps can be adapted to a wide range of substances, even aggressive ones. The pump, with a diameter of just 22 mm and a length of 69 mm for a supply voltage of 24 V, weighs approx. 100 g and can deliver 4.8 to 72 ml/min, at a discharge pressure of up to 5 bar. The gear rim design enables a viscosity range from 0.3 to 100 mPas. In this case, the pulsation is approx. 6% and the differential pressure is between 0 and 5 bar. The construction principle of cycloidal gears, which operates without valves, ensures low shear stresses during delivery.
Compact micromotors
The pump is driven by an electronically commutated DC motor with integrated Faulhaber speed controller. Its brushless construction increases drive life and reliability. A speed controller with the same diameter as the motor, mounted downstream of the motor, ensures speed regulation matched to the motor. In this way, the user can easily set the speed of rotation, via an analog input from 0 to 10 V. A digital input defines the direction of rotation. The digital frequency output provides a 15 mA output signal for further monitoring functions, with 6 pulses per rotation. The supply voltage for the drives is 12 or 24 VDC; in this case, the 22 mm motors have a power of approx. 9 W and a torque of up to 59.9 mNm. The speed controller is supplied with 5 to 28 VDC via a separate ribbon cable. The high efficiency of the motor (approx. 68%) and control electronics (over 95%) ensure long running times, even in battery-powered mobile devices. The robust stainless steel housing and wide operating temperature range (-40°C to +85°C) also enable outdoor use, for environmental measurements in the field. As micromotors have a considerable point overload capacity, they can easily overcome increased initial pump take-off torques (e.g. after night-time temperature drops and fluid viscosity rises).
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