1. Pressure Instruments
Pressure Gauges: These devices measure the pressure in a system and display the value on a dial or digital screen. Common types include Bourdon tube, diaphragm, and digital pressure gauges.
Pressure Gauges
Pressure Transmitters: Used to convert pressure into an analog or digital signal, which can be used for remote monitoring and control.
Pressure Transmitters
2. Temperature Instruments
Thermocouples: A type of temperature sensor made from two different metals that generate a voltage proportional to temperature.
RTDs (Resistance Temperature Detectors): Sensors that measure temperature by correlating the resistance of the conductor with temperature.
Thermocouples
3. Flow Instruments
Flow Meters: Devices that measure the flow rate of liquids or gases. Types include turbine flow meters, magnetic flow meters, and ultrasonic flow meters.
Flow Switches: Used to detect the flow rate and send a signal to other devices to control the flow.
4. Level Instruments
Level Transmitters: Provide continuous level measurement by using technologies like ultrasonic, radar, or capacitive sensors.
Float Switches: Devices that use a float to detect the level of the fluid and activate a switch at certain height levels.
5. Control Valves
Ball Valves: Simple valve with a rotating ball to control flow. Suitable for on/off control.
Butterfly Valves: Features a disk rotating on a diametrical axis inside a pipe, also used for regulating flow.
6. Analytical Instruments
pH Meters: Used for measuring the pH level of liquids.
Conductivity Meters: Measure the electrical conductivity in a solution, often used in water quality testing.
7. Recording and Display Instruments
Chart Recorders: Devices that record various process conditions against time on a paper chart.
Digital Displays: Used to show measurements digitally for easy monitoring.
8. Switches and Relays
Pressure Switches: Activated by a change in pressure.
Temperature Switches: Trigger based on temperature changes.
9. Safety Instruments
Gas Detectors: Devices used to detect the presence of gases in an area, often used as part of a safety system.
Safety Valves: Designed to open to relieve excess pressure and prevent explosion.
10. Analog Instruments
Provide output in a continuous form, usually as needle movements on a dial. Analog instruments are often valued for their precision and simplicity.
Example: Analog voltmeter.
11. Digital Instruments
Provide numerical output on a digital display, offering high accuracy and the ease of direct reading.
Example: Digital multimeter.
12. Passive Instruments
Require external power to operate because they do not generate output on their own.
Example: Strain gauge which requires an external power source for its operation.
13. Active Instruments
Generate output signals on their own, often using internal power sources or the energy of the measured property.
Example: A thermocouple that generates a voltage in response to temperature differences.
14. Deflection Instruments
Indicate a measurement by the movement of a pointer across a scale in response to changes in the physical condition being monitored.
Example: Ammeter using a moving coil to indicate current flow.
15. Null Instruments
Balance a known against an unknown value to achieve a zero or null condition. They are used for high-precision measurements.
Example: Wheatstone bridge for precise measurement of electrical resistance.
