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ASCO - Electrical controlled NAMUR valve

  • Multi-function 3/2-5/2
  • Environmental protection
  • Coil service life - 30,000 operating hours
  • For temperatures down to -25 °C

Product description

Valve according to NAMUR standard for mounting on, among other things, pneumatic rotary attachments. The same valve has 3/2 or 5/2 function depending on which of the two provided intermediate plates is used.

There are many different versions of series 551. It can be provided with most voltage variants, with ATEX approved coil for explosive environments and with a low power pilot valve. In addition to aluminium, housing is available in SS316 steel or brass for low temperatures, - 40 °C. All electrically and air operated valves with aluminium housing have environmental protection as standard. This means that all the internal parts are totally sealed against fluids, dust, corrosive substances etc. that may be present in the direct surroundings.

Even the exhaust from the return chamber is led to the exhaust ports via an internal channel. For further protection, the pilot exhaust can also be led away to prevent contamination entering in this way. The environmental protection makes the 551 series suitable for both dirty environments and clean rooms. The electrical enclosure protection for all models is IP65.

Part numbers

Parts Price Flow factor / flow coefficient Function 1 Function 2 Type of valve
12,5 3/2 Electric, NAMUR Electrically controlled
5/3 Electric, NAMUR, Closed center position
5/3 Vented central position, Electric, NAMUR



Technical data

Connection G1/4
Differential pressure max 10 bar
Differential pressure min 2 bar
Flow factor / flow coefficient 12,5
Flow max 860 l/min
Function 1 3/2
Function 2 Electric, NAMUR
IP class IP65
Material of body Anodised aluminum
Temperature operational max 60 °C
Temperature operational min -25 °C
Type of valve Electrically controlled
Voltage AC 24 V


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