External cage level switches remain one of the most reliable level detection technologies available to process industries. These liquid level switches must perform in a wide range of level control applications, from basic to challenging or even hazardous. In fact, many external cage level switches must comply with the standards set out by industry authorities, such as NACE and ASME, to fulfill safety requirements pertaining to oil and gas processors, power generation plants and other sectors.
When specifying level measurement instrumentation, it’s important to recognize that its design and manufacture should fully support the needs of your critical applications. The float chamber in external cage level switch devices is built to meet specific industry ratings, making its construction an excellent indicator of the quality and reliability of the overall unit. Here are several hallmarks of design integrity of the float chamber.
- Magnetic Attraction Sleeve: no magnet in process to attract ferrous particles
- Spiral Wound Head Flange and E-Tube Gaskets: Suitable for high pressures, high temperatures and steam service
- All Stainless Steel Trim Parts: Corrosion resistant
- Overall Designed for High Pressure: Suitable for the toughest conditions
- Bolting Per ANSI B16.5
- ASME Section IX Welding: Performed by qualified welders to qualified procedures, documented and traceable
- Weld Examination Per ASME B31.1/B31.3: Visually inspected, radiography and liquid penetrant testing as required, documented and traceable
- Welded Float and Stem Assembly: Provides durability
- Hydrostatic Tested at 1.5 Times Rated Pressure, Including Float: Verify pressure boundary with safety margin
- Full Penetration Chamber and Branch Welds: High strength weld
- Integrally Reinforced Forged Branch Outlet (Bonney-Forge style) Couplings: Allows full penetration welds
- Low SG Floats and Displacers: Suitable for most applications
- ASTM Listed Pressure Boundary Parts Procured with Certificate of Conformance: ASME compliance
- Designed With Allowable Stresses Per ASME B31.1/B31.3
- Flanges ANSI B16.5 Compliant
- Welds and HAZ Hardness Tested: Ensures hardness levels compliant with NACE standards
- Post Weld Heat Treatment of All Welded Carbon Steel Components: Ensures hardness levels meet NACE requirements
- Solution Annealing of Stainless Steel Parts as Required: Ensures hardness levels meet NACE requirements
Magnetrol® manufactures an extensive offering of vertical and horizontal float and displacer switch and transmitter devices that represent the industry standards for highly reliable, highly repeatable performance. Unlike some competitive float chambers constructed “to the intent” of ASME standards, MAGNETROL chambers are designed to ASME B31.1, ASME B31.3, NACE MR0175 and MR0103 standards, meeting the toughest industry specifications. Quality engineering benchmarks have resulted in decades of maintenance-free performance from MAGNETROL liquid level switches – some of which have been in the field for as long as 50 years.
For more information about NACE and ASME specifications and float chamber construction, download the MAGNETROL Float Chamber Design Guide.