The following factors are important in making the right commercial and technical choice:

– Valve actuation

• solenoid
• pressure
• proportional
• motorised

– Number of ways

• 2/2 Valve
• 3/2 Valve

– Switching function

• normally closed (NC)
• normally open (NO)

– Connection size

• flow rate
• kv (flow coefficient) value
• Type of connection
• threaded
• flanged
• weld ends

– Working pressure

• upstream of valve
• downstream of valve
• differential pressure
• vacuum

– Process fluid

• neutral to aggressive
• gas to liquid
• filtered to contaminated

– Fluid temperature

• range from – to + °C

– Ambient temperature

• range from – to + °C
• ambient atmosphere

– Solenoid power supply

• voltage
• current
• frequency

– Protection classification

• IP
• EEx

– Control fluid supply

• control fluid
• control pressure
• temperature of control fluid from – to + °C
• ambient temperature from – to + °C

– Accessories and options

– Safety requirements

• TÜV approval/test certificates
• specific certifications

Reference : Norgren