The product
External cage switches – Technology
A permanent magnet is attached to a pivoted switch actuator. As the float/displacer rises following the liquid level, it raises the attraction sleeve into the field of the magnet, which then snaps against the non-magnetic enclosing tube, actuating the switch. The enclosing tube provides a static pressure boundary between the switch mechanism and the process. On a falling level, the float/displacer deactivates the switch.
Features
- Carbon steel float chambers
- Stainless steel float and trim
- Service pressures up to 900 psig (62 bar)
- Process temperatures to +1000 °F (+540 °C)
- Specific gravity ratings as low as 0.34
- Chamber internals accessible via flange top
- Single or multiple switch mechanisms
- 1″, 1½”, or 2″ tank connections available in either NPT, socket weld, flanged side/side or flanged side/bottom constructionOptions
- Dry contact, hermetically sealed and pneumatic switch mechanisms
- Choice of switch enclosure
- Interface level
- Custom materials of construction available upon request
- Customized levels and mounting dimensions
- Vent and drain connections
- High temperature insulation
- Extreme temperature modificationsOperating principle
The buoyancy force of a process liquid on the float causes the float to ride on the liquid surface. The movement of the float with the liquid level moves an attraction sleeve into the field of the switch magnet, pulling the magnet toward the sleeve and actuating the switch.
Approvals
| ATEX | Ex d, Ex ia |
| CCOE | Ex d |
| CSA | XP |
| FM | XP |
| EAC (GOST) | Ex d, Ex ia |
| IEC | Ex d, Ex ia |
| Inmetro | Ex d |
| Korea | Ex d |
| NEPSI | Ex d |
| SIL | SIL 2 (1oo1) |
Other approvals are available.
Consult factory for more details.
