Duplomatic PST4 PSP6 Pressure Switch | PST4/21N-K1/K | Petroleum Industry

The Duplomatic PST & PSP Series from LIC Hydraulic is a premier line of High-Precision Piston-Type Pressure Switches, specifically engineered for the rigorous demands of the Petroleum and Heavy Industrial sectors. Models like the PST4/21N-K1/K provide the critical electrical feedback required to monitor system pressure points with extreme accuracy. Whether integrated into a drilling rig control system or a factory HPU, these switches ensure operational safety and process consistency. We provide 100% drop-in replacements that match original Duplomatic specifications for pressure ranges, electrical ratings, and mechanical mounting.

Technical Highlights

• Pressure Ranges: From $6\text{ bar}$ up to $400\text{ bar}$ across different frame sizes (PST2, PST3, PST4, PST5).

• Repeatability: $\leq 1\%$ of the set point.

• Electrical Connection: DIN 43650 standard connector (K1).

• Durability: Tested for over 1 million cycles in high-vibration environments.

Core Advantages

• Exceptional Precision in Harsh Zones: The PST series features a precision-lapped piston design that minimizes hysteresis, allowing for rapid and repeatable switching even in the presence of rapid pressure fluctuations common in oilfield hydraulics.

• Rugged Construction: Built with a high-strength aluminum or steel housing, the switch is resistant to environmental corrosion and mechanical impact, making it the “gold standard” for offshore and mining equipment.

• User-Friendly Adjustment: The “K” type adjustment allows for fine-tuning of the pressure set-point under load, while the protective cap prevents accidental setting changes due to debris or unauthorized tampering.

• Versatile Switching Logic: Equipped with SPDT (Single Pole Double Throw) microswitches, the PST4 can be wired as either normally open or normally closed, providing maximum flexibility for electrical engineers.

Expert Maintenance Tips

• Setting the Hysteresis: Be aware that mechanical pressure switches have a fixed differential (hysteresis). Always set your target pressure slightly above the required “reset” pressure to avoid rapid cycling or “chattering” of the switch.

• Mounting Orientation: For the best longevity in vibrating environments (like oil rigs), mount the switch vertically. This prevents excessive lateral wear on the piston and ensures consistent spring tension.

• Seal Compatibility: The standard “N” (Buna-N) seals are ideal for most mineral oils. If using water-glycol or fire-resistant fluids common in refinery safety systems, consider specifying Viton (V) seals for chemical resistance.