Pressure Gauges
In various industrial applications, pressure gauges are used to measure the pressures of gases and liquids and to show how hard those substances are pushing against the walls of a container. They come in different types, including differential pressure gauges, which are used to measure how much pressure is lost between two points in a system, and the digital pressure gauges, which give accurate, easy-to-read readings in real time. HVAC and boiler gauges measure both the temperature and water pressure in boilers.
Pressure gauges made of stainless steel are tough and can withstand corrosion. This makes them appropriate for the kinds of environments and processes that are unkind to equipment, such as those involving chemicals and other aggressive fluids that can attack metal under certain conditions. Liquid-filled gauges are also good candidates for these processes, especially if they might vibrate or pulse. The fluid inside the gauge (usually glycerin or silicone) dampens the needle's movement, allowing it to settle at a more stable reading than if the needle were to dance around in the unfilled gauge.
FAQs
What are the measuring ranges of pressure gauges and what is the accuracy and reliability?
The measuring ranges of pressure gauges typically span from vacuum pressures to over 10,000 psi, with accuracy varying from ±0.1% to ±2% of the full scale, depending on the gauge type and application, ensuring reliable performance in monitoring system pressures.
Instrumentation: Elements & Transmitters
2 pieces of hardware used in modern day instrumentation: measuring elements and transmitters.
Measuring Elements
Measuring elements are the part of the device that performs the measurement. For example, the measuring element of a pressure transducer is the part that is actually lowered into a tank that will take a pressure measurement. The measuring element of a flow meter is the part that actually measures the flow and an RTD or thermocouple takes the temperature measurement.
Transmitters
Transmitters collect information from measuring elements and sends the information to where it is needed. The transmitter interfaces with the measuring element and interprets the information. It then sends that information to a PLC, RTU or some other type of control unit. In many cases, the transmitter has the ability to communicate the information via multiple communication protocols. This may be necessary when the measuring element does not send the same type of signal that is needed by the controller. For example, it may be necessary to convert a temperature reading from a thermocouple to a 420 milliamp signal that can be received by a local PLC.