A pressure transmitter is a mechanical device that converts the expansion force of a liquid or gas sample into an electrical output. The pressure transmitters work by opening and closing passageways for gases and liquids in response to changes in temperature, atmospheric pressure, or other external factors.
Virtually any system with pipes, valves, fittings, or pumps can be improved with a properly placed sensor. Piezoelectric transducers use pressure transmitters in many industrial applications such as automotive steering-column sensors and oxygen monitoring systems (affectionately known as “Oxycon”)
What is a pressure transmitter?
A pressure transmitter converts the pressure of liquids or gases into electrical signals using a transducer. The sensors consist of a surface area sensitive to pressure made of materials such as steel or silicon.
Pressure measurement is expressed in Pascals or Newtons per square meter or in pounds per square inch. Pressure transmitters measure absolute, gauge, or differential pressures and are widely used in gas, petrochemical, laboratory, and pharmaceutical industries.
They measure pressure using a pressure sensor, a measurement circuit, and a process connection. Pressure transmitters are commonly used in offshore drilling, oil exploration, onshore petrochemical, gas, chemical facilities, laboratories, and the maritime sector.
Pressure measurement units
Pressure is typically measured in terms of force per unit surface area and is expressed as the value required to stop the expansion of a liquid, gas, or vapor. The most common units used to quantify pressure include Pascals (Pa) or individual Newtons per square meter (1 N/m²) as well as pounds per square inch (psi).
Pressure transmitter types
Pressure transmitters are designed to measure absolute, gauge, or differential pressures. Absolute pressure is the vacuum pressure considered to be 0 psi, while gauge pressure is the total pressure minus atmospheric pressure. On the other hand, differential pressure is the difference in pressure between two points.
Difference between pressure sensors, transducers, and transmitters
While these terms are often used interchangeably, there are some differences between pressure sensors, transducers, and transmitters. Generally, a pressure sensor provides a millivolt output signal, a transducer has an amplified voltage output, and a transmitter offers a 4-20mA output signal. A pressure transducer converts one form of energy into another, while a pressure transmitter converts the electrical signal from the sensor into a larger electrical signal for transmission to other systems.
Pressure transmitters provide a way to test internal fluid pressure accurately. Because they are related to fluid pressure and not to ambient pressure, they are more reliable than other types of pressure measurement. Also, because the transmission line is made of glass, it dissipates heat efficiently, thus making it suitable for the size of low-temperature fluids such as refrigerants.
Pressure transmitters also come with electronic circuits that allow them to be remotely controlled by external circuits. This will enable you to program the unit so that your alarm system will go off when one particular event occurs, or your faucet will turn on when you leave the house. This, of course, makes it ideal for use in burglar alarms, baby monitors, and other security devices.
An absolute pressure transmitter measures the pressure at which a fluid bubble through a nozzle or a point in the pipe and is used on liquids or gases. The transmitter can be used to measure either absolute pressure or maximum working pressure. Total Pressure (AP) transmitters are useful when ambient air pressure is not constant, such as in air conditioning, heating, and water supply systems.
They are also used to measure elevated pressures. Their output is related to standard atmospheric pressure; thus, it does not require calibration at each ambient temperature or velocity change. Its production depends only on absolute pressures and temperatures that are being measured.
A gauge pressure transmitter measures the pressure at which a fluid is traveling through the pipe at a certain point in the line and measures it at that specific point. The transmitter is designed to measure any gas or liquid pressure at a particular point in the line and can be used to measure forces from atmospheric to as high as 200 kPa (1.6 MPa).
Unlike absolute pressure transmitters, gauge measurements are not precise enough for use in critical strain gauges. Its output varies depending upon changes in outside air conditions such as temperature and humidity. In some cases, when measured by each gauge, there is no exact relation between air pressure and liquid or gas flow rate.
Differential pressure is the difference in pressure (or differential pressure). Pressure The distributed force acting vertically on a unit area.
Difference between a pressure sensor, pressure transducer, and pressure transmitter
Generally, a pressure sensor is typically a millivolt output signal, a transducer has an amplified voltage output, and a transmitter offers a 4-20mA output signal.
Use a pressure transducer before a pressure transmitter. A pressure transducer overwrites one form of energy into another form of energy. For example, suppose a pressure transducer converts Celsius to analog energy (mV).
On the other hand, a pressure transmitter overwrites the electrical signal provided by the sensor with a larger electrical signal. For example, the millivolts (mV) from the sensor are converted by the transmitter and transmitted as a voltage or mA. Typically, this more significant electrical signal lies between 1-5 volts or 4-20 milliamperes. Transmitters send the output of your process, liquid or gas process, to your computer.
How does a pressure transmitter work?
Although there are many types of pressure transmitters, they work in almost the same way. Pressure transmitters measure pressure and convert it into an analog electrical signal. In general, pressure transmitters consist of three main components:
- The pressure sensor
- The measurement circuit
- Process connection
The installation of a pressure transmitter measurement system consists of three components:
- The pressure guide tube
- Central measuring diaphragm
- Isolation diaphragm (with silicone oil)
During the operation of the pressure transmitter, the pressure of the medium is transmitted to the central measuring diaphragm, where it is measured. The pressure difference deforms the sheet between these parts. When this deformation is measured, the magnitude of the pressure difference can be measured. This measured pressure difference is converted into an analog electronic symbol that can now be sensed.
The purpose of the pressure transmitter
Pressure transmitters are commonly used in a wide range of industrial applications. Offshore drilling and oil exploration typically use pressure transducers to measure the difference in values between the inside and outside pressure-sensitive equipment. Different parameters must be maintained to ensure the drilling and gathering process is carried out to ethical and efficient standards. This is also true for onshore petrochemical, gas, and chemical facilities. As a result, pressure transmitters significantly reduce maintenance costs.
Pressure transmitters are suitable for many situations, as they can be connected to other systems, such as electrical circuits. Many industries use pressure-sensitive transport and storage equipment to maintain optimal product conditions, which must be accurately monitored to ensure safe delivery and final application.