The ABNM actuator is a thermoelectric actuator for opening and closing valves in the fields of heating, ventilation and air conditioning systems (HVAC).
The actuator mechanism of the ABNM actuator uses a positive temperature coefficient (PTC) resistor heated wax element and a compression spring. The wax element is heated by applying the operating voltage and moves the integrated piston. The force generated by this movement is transferred to the piston, thus opening or closing the valve.
The closing force of the compression spring (100N actuating force) is matched to the closing force of the valves and keeps the valve closed when de-energized. When the control voltage is applied (0-10 V), the wax element is heated under electronic control. The actuator provides active regulation in a defined range between 0.5 V and 10 V.
In the range of 0 – 0.5 V, the actuator remains in a quiescent state in order to ignore ripple voltage occurring in long cables. The relation between control voltage and actuator travel is balanced by optical path measurement, allowing very accurate positioning. When the control voltage is outside of the active range, the valve is kept closed by the closing force of the compression spring.
Control is done by a 0-10 V signal, which is provided either by a room thermostat or, in most cases, by a central direct digital control (DDC) system. The actuator converts the 0-10 V signal into a proportional actuator travel, which can be either linear (ABNM LIN) or logarithmic (ABNM