Electric actuators bring programmable control to injection pumps and samplers

Natural Gas and power generation industries

Typical pneumatic injectors are single acting, positive displacement plunger-type pumps, powered by gas via a diaphragm. Speed control is accomplished by regulating the exhaust gas discharge flow. Volume is controlled by the speed of the pump and by the stroke length.

When used in the natural gas industry, these pneumatic devices release or bleed natural gas to the atmosphere and, consequently, are a major source of methane emissions. In addition, these pumps are limited when gas pressures get below 8 psi.

Electric actuators from Exlar are a perfect solution for replacing pneumatic actuators on pumps or sampling systems. The Tritex Actuator series offers a unique combination of high speed, performance and accuracy, in a compact, lightweight package. One of the main differences with the Exlar solution is how we convert the rotary motion of a motor to a linear force with use of a roller screw integrated with the motor.

The roller screw is extremely efficient, provides very precise positioning capabilities and life counts in the hundreds of millions of cycles. The design allows the motor to be wrapped directly onto the outer shell; rotating the roller screw up to the full RPM’s of the motor. This allows the linear movement to be as fast as 30 inches per second; perfect for high stroke needs on plunger pumps and sampling systems.

The Tritex is fully programmable for various speeds or strokes. Communication choices include Modbus RTU, Ethernet IP, analog and simple digital I/O. Diagnostic information can be communicated via SCADA. For simple applications, speed adjustment can be made with a simple port. No mechanical stroke limiters are needed.