External Cage Level Switch
Liquids stored in tanks or vessels need to be monitored for level in a multitude of industrial, agricultural, and energy applications. An external cage level switch is an appropriate tool for measuring liquid levels for many of these settings. It is important to understand what an external cage level switch is, how it works, the many applications, and how to choose the best one. If you are looking to gain more information about external cage level switches, read this guide.
What is an external cage level switch?
The primary purpose of a level switch is to determine if and when a media reaches a specific level. Once the media reaches the level, a signal is sent from the switch to another device like a display, actuator, or pump. An external cage level switch tracks level changes in liquids. An external cage level switch consists of carbon steel float chambers, stainless steel float and trim, a magnet, a pivoting switch actuator, a displacer, an attraction sleeve, a switch, and an enclosing tube.
Some external cage level switches have a single switch mechanism, and others have multiple switch mechanisms. External cage level switches can be customized with the following options:
- Hermetically sealed or pneumatic switch mechanisms
- Different types of switch enclosures
- Different types of interface levels
- Customized construction materials
- Customized levels and mounting dimensions
- Vent and drain connections
- Insulation for high temperature environments
- Modifications for extreme temperature conditions
How does an external cage level switch work?
Within an external cage level switch, a permanent magnet attaches to a pivoted switch actuator. As the liquid level changes, the float or displacer rises in response. The rising of the float or displacer raises the attraction sleeve into the zone of the magnet. The attraction sleeve snaps against the non-magnetic enclosing tube to activate the switch.
Applications of an External Cage Level Switch
An external cage level switch can be used in a variety of applications, including:
Chemical
- Catalysis vessels
- Chemical reactors
- Deionization tanks
- Neutralization
- Surge drums
- Heat Recovery Steam Generator (HRSG) for power/utilities
- Scrubber vessels
- Ammonia storage
Crude Oil
- Crude desalting
- Production fluid storage
- Process and field storage tanks
- Wellstream separation
Natural Gas
- Flare knock-out drum
- Gas dehydration
Nuclear Power
- Containment and drainage sumps
- Liquid waste storage
- Spent fuel pools
- Emergency coolant tanks
- Scram discharge volume tanks
- Turbine steam generators
- Scram discharge volume tanks
Petroleum Refining
- Catalysis vessels
- Crude desalting
- Coking operations
Power Generation
- Boiler blowdown tanks
- Condensate receiver tanks
- Deionization tanks
- HRSGs
- Condensate drip legs
- Condensate storage
- Flash tanks
- Preflash drums
- Feedwater heaters
- Ammonia storage
Pulp and Paper
- Black, green, and white liquor
- Condensate receiver tanks
How to Choose the Best External Cage Level Switch
TechStar is your manufacturing representative for instrumentation, automation, and analytical products, service and training. We stock a full range of external cage switches to meet your instrumentation needs. Let’s take a look at a few different types of external cage level switches and how to choose the right one for your use application.
Side-Mounted Level Switches
Flanged external cage type level switches are completely self-contained units designed for side mounting to a tank or vessel with threaded, socket weld, or flanged pipe connections.
Refrigerant Level Switches
J52 refrigerant level switches are float actuated units designed for use on liquids with 0.60 specific gravity and higher.
High-Pressure Liquid Level Switches
High-pressure liquid level switches are displacer actuated units, utilizing a single switch mechanism for level alarm or control functions. These units are designed for service pressures up to 5000 psig and liquids with specific gravities of 0.40 and higher.
High-Pressure, High-Temperature Liquid Level Switches
B40 liquid level switches are external cage type level switches that have float-actuated control specifically designed and constructed for high-pressure, high-temperature service conditions such as boilers.
Boiler and Water Column Liquid Level Switches
Models C24/C25 boiler and water column liquid level switches are single- or multi-switch units that offer versatility and reliability in a variety of applications.
Float Actuated Liquid Level Switches
Series 3 float-actuated level switches are designed to provide critical alarm set points in clean liquid applications. They meet ASME B31.1 or ASME B31.3 requirements.
Self-Contained External Cage Liquid Level Switches
Series B73 and 75 external cage type level switches are completely self-contained units designed for side mounting to a tank or vessel with threaded, socket weld, or flanged pipe connections. These float-actuated controls have proven their reliability in process control for decades.
To acquire one of these external cage level switches, visit TechStar today.