Level Instrumentation

1
Level Instrumentation

• Understanding Instrumentation Technology

2
Level instrumentation

• Introduction
• Transmitters
• Switches
• Controller and displays
• Putting it all together

3
What is Level Instrumentation?

• The control of a liquid in a container
• The ability to control a device (pump, valve or
  alarm)
• The ability to monitor the amount of liquid in s
  tank or vessel

4
Factors to consider?

• Maximum and minimum temperature
• Real and design.
• Maximum and minimum pressure
• Real and design
• Tank geometry, including installation ports
• Process chemicals
• Tank construction

5
What do We Really Want to Do?

• Know when tank is empty
• Know when tank is full
• Know how much is in the tank
• Activate an alarm
• Control a pump
• Control a valve

6
High and/or Low Alarm

• To know when either a high or low level is
  reached
• Used to turn off a pump or valve to prevent a
  tank from over flowing or running dry
• Used to activate an alarm (light or horn) when
  tank is either full or empty

7
Automatic Empty

• To automatically empty and tank or vessel
• Always requires two-points
• Where empty starts
• Where empty stops
• Typically uses a pump or valve to empty liquid
• Sump is the most common application

8
Leak Detection

• To know when a tank, vessel or pipe is leaking
  liquid
• Liquid could be hazardous, expensive or both
• Secondary containment is Ideal location for a
  level switch to detect leaks
• Secondary containment can also be a pipe or sump

9
Automatic Fill

• To automatically fill a tank or vessel
• Always requires two-points
• Where fill starts
• Where fill stops
• Typically uses a pump or valve to fill tank or
  liquid
• Bulk storage or day tanks are the most common
  applications

10
Inventory Control

• To know the amount of liquid in a tank or vessel
• Typical output is
• Current (420 mA)
• Voltage ( 05 VDC or 010 VDC)
• Output can be used to indicate level in height
  (inches, feet, etc.) or volume (gallons, etc.)
• Output connects to display, PLC, SCADA, DCS, etc

11
5 Basic Level Applications

• High and/or low alarm
• Leak detection
• Automatically fill a tank
• Automatically empty a tank
• Inventory control
• Any of these can be combined for
  multiple-functions

12
Conclusion of Training