How does Pressure Transmitters work?
A pressure transmitter, or pressure transducer, is a transducer that changes pressure into an analog electrical signal. While there are numerous types of pressure transmitters, the strain-gauge base transducer serves as the most popular. As such, first we will outline strain-gauge base transducers, as well as other common types, three major pressure references, and primary pressure signal outputs.
Strain-Gauge Base Transmitters
In this transducer, conversion is possible through the physical deformation of strain gauges that are bonded into the transducer’s diaphragm and wired into a Wheatstone bridge arrangement. The pressure employed on the transducer delivers a diaphragm deflection which imposes strain on the gauges, generating an electrical resistance change proportional to the pressure. Strain-gauge base transducers are composed of a force collector like an elastic diaphragm and a transduction component that employs a dependent resistive, inductive, or capacitive method to generate an electrical signal. Meanwhile, they utilize the strain gauges to measure the force operating on them.
Generally, the strain gauges can handle deformation, and this deformation produces a variation in voltage. Keep in mind that the pressure measurement is determined by the degree of variation detected in the voltage. As they apply capacitance or piezoelectric sensors instead of strain gauges, strain-gauge base transducers are considered exceptional devices. More than that, they are preferred for their range, work environment, and accuracy.
Static Pressure Transmitters
Static pressure transmitters, on the other hand, estimate the pressure of a stagnant fluid and serve as primary pressure monitoring tools. When a fluid places pressure on the transducer, the strain gauge begins to deform. The resulting variations of voltage correspond with the strength of the pressure. As soon as the pressure discharges, the strain gauge turns to its original configuration.
Piezoresistive Strain Gauge Pressure Transmitters
Conventional piezoresistive strain gauge pressure transmitters utilize strain gauges secured to a flexible diaphragm so that any variation in pressure generates a small deformation, or strain, in the integrity of the diaphragm. This alters the strain gauges’ resistance which presents a suitable conversion of the pressure measurement as an electrical signal.
Capacitance Pressure Transmitters
A variable capacitance pressure transmitter has a diaphragm and an additional electrode affixed to an unpressurized surface with a clearance between the diaphragm and the electrode. The pressure variations either extend or narrow the clearance which alters the capacitance to produce a signal.
Pressure References
There are three general pressure references for measuring pressure. However, there are other types, such as sealed or vacuum gauge, all of which can be categorized into three major classes: absolute, gauge, and differential pressure.
- Absolute Pressure measures the pressure relative to a complete vacuum and makes absolute zero a point of reference. A barometric pressure transducer serves as one example.
- Gauge Pressure measures the pressure relative to atmospheric pressure like a tire pressure sensor would.
- Differential Pressure measures the difference between two pressures on each side of the sensor, with a liquid pressure transducer being the most common example.
Primary Pressure Signal Outputs
A pressure transducer produces an electrical output signal that is similar to the pressure affixed to an electrical source and a pressure source. Typically, this signal is in the form of current, voltage, or frequency.
- Digital pressure transducers produce a digital signal and usually express their location, log data, calibration information, and more.
- Millivolt output pressure sensors produce an output that is proportional to the pressure transducer input excitation or power directly. These devices can handle harsh operational settings, have a compact design, and are better suited for short distance applications.
- Voltage pressure transmitters produce output signals in the 0-5dc or 0-10Vdc range and present a higher output when compared to a millivolt transducer due to their integral signal condition. Since they have higher level outputs, they are not sensitive to noise, making them ideal for noisy industrial environments.
Conclusion
Aviation Gamut is a leading distributor of a wide array of transmitter types like adapter transducers, bearing wheel transducers, sensor accessories, strain gauge hubs, electrode assembly battery components, electrical transformers, circuit breakers, and so much more. With over 2 billion options on our database, customers can easily fulfill their operational requirements. Submit a Request for Quote (RFQ) form today or contact us directly; we are available 24/7x365!
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