The STONEL QX33K05HDM QX35CK02SDM QX35CK05HDM series comprises three high performance heavy duty limit switch boxes engineered to deliver multiple independent contact outputs for critical valve position monitoring in demanding industrial environments. STONEL, a globally recognized brand in valve automation accessories, has designed these models to address applications ranging from high density feedback requirements to safety instrumented functions and explosion proof installations. This series is ideal for oil and gas pipelines, chemical reactor isolation valves, turbine inlet control systems, mining slurry circuits, and any process requiring robust, multi channel valve status confirmation.

The STONEL QX33K05HDM is a heavy duty limit switch box featuring five independent mechanical microswitches within a compact die cast aluminum enclosure. This high density configuration provides five SPDT contact outputs, enabling operators to monitor fully open, fully closed, and three intermediate positions simultaneously. Each microswitch is rated at 10A 250V AC with silver alloy contacts for reliable switching of solenoids, pilot lights, and PLC inputs. The enclosure is powder coated for corrosion resistance and rated IP66 and IP67, offering complete dust protection and resistance to temporary immersion. Five externally adjustable cam lobes allow independent setpoint tuning over 0 to 120 degrees of rotation without removing the cover. A high visibility visual position indicator with 360 degree readability confirms valve status from any direction. Two M20 cable entries are provided, and operating temperature ranges from -40°C to +85°C. The STONEL QX33K05HDM is the preferred choice for complex valve sequencing, partial stroke testing, and diagnostic applications where five independent feedback signals are required from a single compact unit.

For safety instrumented systems requiring documented reliability, the STONEL QX35CK02SDM offers a flameproof enclosure with two SIL capable microswitches. This model carries ATEX II 2 G Ex db IIC T6 certification for Zone 1 and Zone 2 hazardous areas, and the microswitches are selected and tested per IEC 61508 for SIL 2 capability. Each unit receives a unique serial number and comes with a certificate of conformance including mean time to failure data. The STONEL QX35CK02SDM features a heavy duty aluminum housing with a 2 meter factory sealed cable instead of traditional cable entries, eliminating field wiring and potential ingress points. The two SPDT switches are rated at 6A 250V AC and include gold plated contacts for low energy switching reliability. An external cam adjustment mechanism and a bright visual position indicator complete the package. Operating temperature spans -40°C to +80°C, and the enclosure is rated IP66 and IP67. This STONEL model is specifically designed for emergency shutdown valves, high integrity pressure protection systems, and burner management applications requiring certified SIL performance in hazardous areas.

When both high contact density and flameproof certification are needed, the STONEL QX35CK05HDM delivers five independent microswitches within an ATEX Ex db IIC T6 certified aluminum enclosure. This model combines the multi contact capability of the QX33 series with the hazardous area approval of the QX35 platform. Five mechanical snap action switches each rated at 6A 250V AC provide five SPDT outputs for open, closed, and three intermediate positions or alarm contacts. The enclosure is factory sealed with a 2 meter heavy duty cable, similar to the SDM version, ensuring a completely sealed system. Five individually adjustable cam lobes allow precise setpoint configuration. An external visual indicator with high contrast colors and IP66 IP67 protection ensures reliable operation in outdoor and hazardous locations. The STONEL QX35CK05HDM is the ultimate solution for complex valve feedback requirements in petrochemical refineries, offshore platforms, and gas compressor stations where both multiple signals and explosion proof safety are mandatory.

All three STONEL models share NAMUR VDI VDE 3845 mounting interfaces with standard drive shaft adapters for 9mm, 11mm, and 14mm square or double D actuator stems. The die cast aluminum construction of the QX33 and QX35 series provides excellent mechanical impact resistance and heat dissipation. External cam adjustment eliminates the need to open the enclosure for setup, preserving the flameproof seal in certified models. Each unit undergoes full functional testing before shipment, and optional SIL documentation or extended cable lengths are available upon request. For plant engineers seeking a family of heavy duty limit switches that scales from five contact general purpose to two contact SIL certified and five contact flameproof, the STONEL QX33K05HDM QX35CK02SDM QX35CK05HDM series delivers application specific reliability backed by STONEL global engineering support. Trust STONEL for multi contact valve position feedback that performs safely and dependably in the harshest process environments.