CASE STUDY
Design and Construction of 4 ATEX-Certified
Hydraulic Power Units for Industrial Silo Slide Gates
APPLICATION GOAL
Sector and Function
The power units were developed to operate slide gates (knife gate valves) on industrial silos located in zones classified as potentially explosive.
Customer Requirements
The main requirement was the exclusive use of IECEx/ATEX-certified electrical components to ensure maximum operational safety in hazardous environments.
DESIGN AND COMPONENTS
Key Components Selected
– AISI-316 stainless steel tank, corrosion-resistant and compliant with standards for aggressive environments.
– C5M-coated steel enclosure with doors and panels, designed for enhanced protection in marine or highly corrosive environments.
– Fixed-displacement gear pump, for reliable flow delivery.
– 24VDC ON/OFF valve, for simple yet effective control.
– ISO 6020/2 cylinders with overcenter valves, ensuring safety and holding capability during gate movement.
System Performance
– Operating pressure: 100 bar
– Flow rate: Fixed
– Circuit type: Standard open loop
Thermal Management and Filtration
– High-capacity heat exchanger, specifically designed for hot climates with ambient temperatures up to 48 °C.
INNOVATION AND CUSTOMIZATION
Tailored Solutions
– Compact footprint, defined in collaboration with the client to fit the available installation space.
– Customized labeling, to simplify installation and maintenance procedures.
Challenges and Solutions
Component selection required special attention:
– Siemens/Innomotics special electric motors, for IECEx compliance.
– ATOS solenoid valves, a leading brand in components for classified areas.
Distinctive Features Compared to a Standard Power Unit
– Use of IECEx-certified electrical components
– AISI-316 tank with protective coating for extreme environmental conditions
– IECEx-marked AISI-316 junction box
CONTROL, MAINTENANCE & SAFETY
Sensors and Monitoring Devices
– 2 IECEx level switches
– 1 IECEx PT100 probe (4-20 mA), for temperature monitoring
Diagnostics and Accessibility
– While no digital predictive systems are implemented, the installed sensors provide essential monitoring data.
– All units are designed with easy access to main components, such as filter cartridges, to simplify routine maintenance.
Regulatory Compliance
– The power units are classified as “partly completed machinery” under the Machinery Directive 2006/42/EC, with incorporation declaration (Annex II1B).
– Design and construction in accordance with UNI EN ISO 4413, the reference standard for hydraulic systems and components.
– Electrical components are selected in compliance with IECEx certification, an internationally recognized voluntary standard for use in hazardous areas.
CONCLUSION
This project—entirely managed, designed, and delivered by Fluid System—represents a successful integration of explosion-proof safety requirements, customized engineering, and reliable technical solutions. The four ATEX-certified hydraulic power units provide an effective response to both environmental and regulatory challenges in the industry, while maintaining high standards of quality and reliability.
