The Fischer Mess NK10400000010000 is a mission-critical safety low-liquid-level limiter belonging to the specialized NK10 Series engineered and manufactured by FISCHER Mess- und Regeltechnik GmbH (Germany) – a globally recognized benchmark in industrial pressure, level, and thermal system safety instrumentation. The device is purpose-built to provide fail-safe low-level limitation (Low Level Limiter / Level Cut-Out) to prevent dry firing, excessive thermal stresses, and catastrophic tube rupture across organic heat transfer plants (thermal oil heaters) and industrial boiler plants.

Unlike conventional flanged models, model NK10400000010000 features direct pipe butt-weld connection ends with an outer diameter of Ø 82.5 mm (Welding ends / Schweißenden Ø 82.5 mm). This welded configuration provides permanent leak-tight integrity, completely eliminating flanged gasket degradation while offering superior resistance against intense pipeline vibrations and cyclic thermal stresses. The limiter functions via an internal stainless steel float mechanism coupled with a heavy-duty, hermetically separated permanent magnetic transmission system: when the liquid level falls below the predetermined safety limit, the magnetic float triggers an instantaneous trip in the integrated potential-free microswitch contact, commanding the burner management system to execute an emergency safety shutdown. Because the magnetic transmission operates completely contact-free across a solid chamber wall, dynamic seals and packing glands are entirely absent, preventing any hazardous hot fluid leaks into the plant atmosphere. The unit holds full TÜV Type Approval certification conforming to DIN 4754 (safety requirements for heat transfer installations using organic heat transfer fluids) and complies with industrial boiler standards DIN EN 12952 / DIN EN 12953, delivering unmatched operational reliability for severe thermal processes.

• Manufacturer: FISCHER Mess- und Regeltechnik GmbH
• Brand Origin: Germany
• Full Order Code: NK10400000010000
• Product Classification: Industrial Level Limiter / Safety Low Level Cut-Out (NK10 Series)
• Safety Function: Low liquid level limitation with fail-safe interlock trip for industrial burners/heaters
• Standards & Safety Approvals:
  - TÜV Component Type-Tested according to DIN 4754 (Heat transfer installations operating with organic heat transfer fluids)
  - Compliant with industrial boiler safety standards DIN EN 12952 / DIN EN 12953 / DIN EN 12828
  - Functional Safety Suitability: Suitable for SIL (Safety Integrity Level) safety architectures
• Compatible Media: Thermal oil (organic heat transfer fluids, synthetic/mineral thermal fluids), hot water, steam boiler water, and high-temperature industrial process liquids
• Maximum Medium Temperature: Up to 350°C (optional executions up to 400°C)
• Maximum Operating Pressure: 10 bar (PN16 / PN25 structural pressure design rating)
• Mechanical Process Connection: Butt-weld pipe ends (Welding ends / Schweißenden) outer diameter Ø 82.5 mm
• Sensing Principle: Mechanical float mechanism with non-contact permanent magnetic coupling (glandless, leak-free design)
• Electrical Output: Integrated volt-free safety microswitch contact (SPDT changeover contact)
• Contact Electrical Rating: 250V AC, 2A / 24V DC
• Enclosure Protection Rating: IP65 according to EN 60529 (Total dust ingress prevention and water-jet resistance)
• Measuring Chamber & Body Materials: High-strength weldable boiler steel P250GH combined with Stainless Steel 1.4571 (AISI 316Ti)
• Float Construction: Monolithic sealed high-grade stainless steel float engineered for elevated pressure and temperature
• Ambient Operating Temperature at Terminal Enclosure: -20°C to +70°C
• Mounting Orientation: Vertical mounting on welded bypass chambers, expansion vessel balance lines, or thermal fluid piping
• Industrial Safety Applications: Industrial thermal fluid boilers and heaters, thermal oil expansion vessels, textile/wood/food industrial drying and heating plants, steam boilers, and industrial hot fluid circulation skids