The STONEL QX35CR05SRA QX35K02HDM QX35K05HDM series represents a premium family of flameproof limit switch boxes engineered for hazardous area valve position monitoring where safety, durability, and contact density are critical. STONEL, a globally respected brand in industrial automation, has designed these three models to serve a wide spectrum of applications ranging from corrosive offshore environments to general purpose refinery installations, all while carrying ATEX Ex db IIC T6 certification. This series is ideal for emergency shutdown valves, burner management systems, chemical reactor block valves, and pipeline isolation stations operating in Zone 1 and Zone 2 explosive atmospheres.

The STONEL QX35CR05SRA is a specialized flameproof limit switch box constructed entirely from 316L stainless steel with an electropolished finish, offering exceptional corrosion resistance for the harshest marine and chemical environments. This model contains five independent mechanical microswitches, each rated at 5A 250V AC with gold plated contacts for reliable low energy switching. The stainless steel enclosure is fully welded and rated IP66 and IP68, providing complete protection against salt spray, acidic vapors, continuous immersion, and high pressure washdowns. Five externally adjustable cam lobes allow independent setpoint configuration over 0 to 120 degrees of rotation without opening the flameproof cover. An integral 2 meter heavy duty cable exits the enclosure through a factory sealed stainless steel strain relief, eliminating field wiring and potential ingress points. The STONEL QX35CR05SRA includes a high visibility visual position indicator with a chemically inert polycarbonate dome, and operates from -40°C to +120°C. This model is the definitive choice for offshore platforms, marine loading arms, chlorine production facilities, and any installation where both flameproof safety and stainless steel corrosion resistance are mandatory.

For standard heavy duty applications requiring flameproof certification without the premium of stainless steel, the STONEL QX35K02HDM offers a die cast aluminum enclosure with a durable polyester powder coating. This model features two independent mechanical microswitches rated at 10A 250V AC, suitable for direct switching of solenoid valves, alarms, and PLC inputs. The housing is certified ATEX II 2 G Ex db IIC T6 and IECEx, with IP66 IP67 ingress protection. Two M20 cable entries are provided, and external cam adjustment allows quick stroke setting. A bright visual position indicator provides local status. The STONEL QX35K02HDM operates from -40°C to +85°C and is the economical workhorse for refineries, petrochemical plants, and gas compressor stations where dual contact feedback is sufficient.

When higher contact density is needed in a standard aluminum flameproof enclosure, the STONEL QX35K05HDM delivers five independent microswitches within the same rugged housing as the K02 model. Each of the five SPDT switches is rated at 6A 250V AC, providing five separate output channels for monitoring fully open, fully closed, and three intermediate positions, or for redundant signaling in safety loops. Five independently adjustable cam lobes allow precise setpoint tuning. The STONEL QX35K05HDM retains the same ATEX Ex db IIC T6 certification, IP66 IP67 rating, two M20 entries, and visual position indicator as its dual switch counterpart. This model is ideal for complex valve sequencing, partial stroke testing with position verification, and diagnostic applications requiring multiple feedback points from a single flameproof limit switch box.

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 QX35 series features external cam adjustment accessible via a sealed hex socket, allowing setup without compromising the flameproof integrity of the enclosure. Each unit is 100 percent functionally tested and pressure checked before shipment, and full ATEX, IECEx, and optional SIL documentation is provided. For plant engineers seeking a flameproof limit switch family that spans stainless steel multi contact, aluminum dual contact, and aluminum five contact configurations, the STONEL QX35CR05SRA QX35K02HDM QX35K05HDM series delivers certified safety, application matched contact density, and long term reliability. Choose STONEL for hazardous area valve feedback solutions that perform safely and dependably in the world’s toughest industrial environments.