Chemical Metering Pump Controls

Aquflow hydraulic metering pump

Aquflow pumps are as easy to control as they are to install and run. Since a metering pump is a positive displacement pump you can control the flow capacity by adjusting the stroke’s length and/or speed.

Stroke Length

By adjusting the stroke length, you are controlling the displacement volume per stroke. This can be achieved either manually or automatically through the following options:

 Aquflow stroke length adjuster controls the displacement volume per stroke


Our standard hydraulic diaphragm metering pump’s volume (capacity)  can be adjusted from 100% down to 10% by changing the stroke length without compromising the accuracy. Our pumps are factory set at 100% of the maximum pump capacity and can be adjusted by turning the manual knob to the preferred percentage. The stroke length of AquFlow pumps can be adjusted while the pump is running. This makes achieving the exact amount of flow very easy and accurate.


Aquflow’s Electronic Capacity Control Adjuster (ECCATM) permits the automatic control of pump capacity by changing the stroke length. Replacing the standard manual micrometer knob and mounting directly on the pump, the ECCA uses miniaturized, state-of-art electronic technology built around an AC synchronous motor. This permits precise actuator travel, without hunting or overshoot.


AquFlow’s Pneumatic Capacity Control (PACOTM) permits the automatic adjustment of pump capacity. Replacing the standard manual micrometer knob and mounting directly on the pump. the PACO permits remote capacity adjustment from a manual loading station and/or a response to an instrument air signal from a process controller.

Stroke Speed

Based on our customer’s requirements, we provide the option of controlling the stroke’s speed by utilizing a Variable Frequency Drive (VFD) for an AC motor and a Variable Speed Drive (SCR) for a DC motor to achieve a lower flow rate.

Variable Frequency Drive

The HydroDriveTM AC Variable Frequency Drive is a variable speed control in a NEMA 4X (IP-65) washdown, watertight enclosure. It is designed to operate 208-230 Volt 3-Phase AC induction motors through 3.6 Amps RMS. The sine wave coded Pulse Width Modulated (PWM) output operates at a frequency of 16Hz which provides high torque and efficiency at a low noise level.

Variable Speed Drive

Specifically designed for use with metering pumps, the Nikkiso HydroDriveTM DC SCR Variable Speed Drive is a NEMA 4X (IP-65) variable speed motor control for shunt wound or permanent magnet motors. Its rugged, die cast aluminum housing is protected with an acrylic coating for the ultimate in corrosion resistance, making it suitable for application requiring washdown, watertight integrity. All switches are sealed with rubber boots  and the manual speed adjustment potentiometer incorporates a shaft seal.

Dual Axis Pump Control

By combining both stroke length and speed we get control and fine resolution. Use either the manual or automative stroke length adjuster with the VFD to control pump speed.