differentieeldruktransmitter

A differentieel druktransmitter, often shortened to DP transmitter, is an instrument used to measure the pressure difference between two points in a process. This measured pressure difference is then converted into an electrical signal, typically a 4-20 mA current or a digital output, which can be interpreted by a control system or display. DP transmitters are crucial in various industrial applications for determining flow rates, liquid levels, and pressure drops across equipment.

The core of a DP transmitter usually consists of a sensing diaphragm. When a pressure difference exists across this diaphragm, it deflects. This deflection is then sensed by a transducer, which could be capacitive, piezoresistive, or strain gauge-based. The transducer converts the physical displacement of the diaphragm into a measurable electrical signal. The transmitter circuitry then amplifies, linearizes, and conditions this signal before outputting it.

Common applications include measuring the flow of liquids or gases through a differential pressure flow element like an orifice plate, venturi tube, or flow nozzle. The pressure taps are located upstream and downstream of the flow element, and the resulting pressure difference is proportional to the square of the flow rate. For level measurement in open or closed tanks, DP transmitters can be used by measuring the hydrostatic pressure exerted by the liquid column. They are also employed to monitor filter status, detect blockages in pipelines, and control pump speeds based on pressure differentials.