MODULE 5: Level Measurement And Control Flashcards
In all _________________ a sensing device element, or system interacts with material inside a container. A wide variety of physical principles are used to measure level.
LEVEL MEASUREMENT
Common types of level measurement: (5)
- sight
- pressure
- electric
- sonic
- radiation
Types of level measurements:(2)
- Direct level sensing
* Indirect level sensing
The actual level of the fluid is monitored
DIRECT LEVEL SENSING
The property of the liquid such as pressure and electrical characteristics is sensed to determine the liquid level.
Indirect level sensing
Types of direct level sensing:(3)
- sight glass or glass gauges
- displacer
- floats ( angular arm or pulley)
Two types of level gauges:(2)
- tubular
* flat
Works the same way as the manometer, that is, as the liquid vessel rises or falls the liquid in the glass tube will also rise or fall.
Tubular type
The gauges are made of ________,_________ or a combination of the two materials.
- glass
* plastic
The material from which the transparent tubes are made must be able to withstand the pressure in the vessel, and they are generally limited to _____psig at 400’F.
450
Operates on archimedes principle states that a body fully or partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced.
Displacer level gauges
Most direct method for measuring level
Floats (angular arm or pulley)
A tape is connected on one end and to counterweight on the other to keep the tape under constant tension.
Floats (angular arm or pulley)
The float motion makes the counterweight ride up and down a direct-reading gauge board.
Float
Is calibrated to indicate the liquid level in the tank.
Gauge board
