Introduction

The DS-104/EX piston pressure switch is a precision device designed for use in explosive atmospheres (Zone 1), compliant with ATEX Directive 2014/34/EU. Manufactured by HYDROPA, it is recognized across Europe for its reliability, broad application range, and durable precision. The device is certified with ATEX marking II 2G IIC T6, suitable for ambient temperatures from -20°C to +70°C.

Functionality

The pressure switch operates on a piston-spring principle. When pressure is below the setpoint, the microswitch is activated. As pressure increases, the piston compresses a spring until the set pressure is reached, releasing the microswitch and triggering an electrical signal. The switching pressure is adjustable via a rotary element: turning counterclockwise lowers the switching pressure, clockwise increases it. A locking screw secures the adjustment, and a mechanical stop prevents over-rotation of the spring.

Technical Specifications

• Switching Pressure Ranges: Various ranges from 5 to 350 bar depending on piston diameter (4 mm or 5 mm).
• Repeatability: Deviation less than 1% depending on application.
• Operating Temperature: -20°C to +70°C.
• Fluid Compatibility: Mineral oil.
• Switch Element: BARTEC miniature microswitch type 07-2501.
• Electrical Ratings: Up to 250 V AC/DC, 5 A resistive and inductive load.
• Protection Class: IP65 according to DIN 60529.
• Housing: Painted aluminum.
• Connection: G ¼ internal thread, 4 m cable length.
• Max Pressure: Up to 500 bar with standard seals, up to 600 bar with special seals.
• Viscosity Range: 10 to 800 mm²/s.
• Switching Path: Approximately 0.5 mm, minimizing wear.

Durability and Usage Recommendations

The lifespan depends on pressure extremes, switching frequency, hydraulic vibrations, and electrical load. Installation must avoid harmful vibrations; using damping materials can significantly extend service life. HYDROPA offers tailored solutions based on extensive experience with materials and manufacturing tolerances.

Connection and Ordering Information

The device is available in various configurations for pipeline or control panel installation, with options for adjustment knobs (including lockable versions), housing materials (brass), and special low-friction seals. Pressure ranges and maximum pressures vary by model. Factory preset switching points are available, with options for rising or falling pressure activation. Grounding must be ensured separately, typically via the pipeline.

Hysteresis and Switching Differential Pressure

Two seal types affect hysteresis:

• Standard Seal: Hysteresis of approximately 7-12% of the set pressure at 60-70% of max switching pressure. Example: At 100 bar setpoint, hysteresis is about 8-15 bar.
• Low-Friction Special Seal (SS version): Hysteresis reduced to 3-6%. Example: At 200 bar setpoint, hysteresis is about 12 bar.

Hysteresis values depend on temperature, fluid viscosity, and piston diameter.

Dimensions and Mechanical Details

Detailed device dimensions are provided for different model variants, including versions with scale-adjustable knobs and lockable adjustment. The scale is for orientation only; precise pressure setting requires a manometer.

Safety and Certification

The DS-104/EX is equipped with a BARTEC microswitch certified under EPS 14 ATEX 1689 X. The device consists of non-electrical and electrical parts, with documentation filed according to ATEX Directive 2014/34/EU. Installation must be performed by qualified electricians following national and international electrical standards (DIN EN 50178, SELV, PELV). Power must be disconnected before wiring.

Manufacturer Information

HYDROPA Hydraulische Erzeugnisse GmbH & Cie. KG
Därmannsbusch 4, D-58456 Witten, Germany
Phone: +49 2302 70 12 0
Fax: +49 2302 70 12 47
Email: [email protected]
Website: www.hydropa.de