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NF551H402 551H402 ASCO 551 Series 1/4 Inch Pilot Operated Aluminium Body Solenoid Valve

1. Port size: 1/4 inch
2. Material: Aluminum
  • NF551H402 551H402
  • ASCO

1. Product Name: NF551H402 551H402 ASCO 551 Series 1/4 Inch Pilot Operated Aluminium Body Solenoid Valve

2. Samples

You can send a sample to customize the products, we have many engineers can help it; If you want a product of mine, but you are not sure if it's what you want, so you can ask for a sample from me, it will be free.

3. Drawing


prefix option plage
A B C D E weight
monostable 5/2 bistable - 5/3
SC BP 125 174 107.7 22.5 86.5 0.86 1.37

4. Product show



• The monostable spool valves in conformity with IEC 61508 Standard (2010 route 2H version) have TÜV (551 series) and EXIDA (551-553 series) certified with integrity levels: SIL 2 for HFT = 0 / SIL 3 for HFT = 1

• The spool valves have threaded port connections and "NAMUR" style interface

• The same spool valve can be adapted for 3/2 NC or 5/2 function for controlling double-acting and single-acting actuators

• All the exhaust ports of this spool valve are connectable, providing better environmental protection, particularly recommended for sensitive areas such as clean rooms, and applications in the pharmaceutical and food processing sectors

• The valve offers environmental protection against the ingress of liquids, dusts or any other foreign matter (environmentally-protected construction)

• Can be externally piloted (external air pilot supply) to convert valve to zero minimum operation by flipping a gasket

• The solenoid valves satisfy all relevant EU Directives


Differential pressure   2 - 10,4 bar [1 bar = 100 kPa]

Flow (Qv at 6 bar)      1/4 = 700 l/min (ANR)

                                 1/2 = 3000 l/min

fluids                         air, inert gas, filtered

temperature range     - 25°C to + 60°C

seal materials             NBR (nitrile) + PUR (polyurethane)


Ensure that the compatibility of the fluids in contact with the materials is verified

Body                                  Aluminium, black anodized

End cover (spring)              Glass-filled PA

Interface plates                  Glass-filled PA

Spool valve internal parts    Zamak, stainless steel, (POM), aluminium

Pilot internal parts              Refer to specific solenoid catalogue pages

Pilot end covers                  Aluminium

Core tube                           Stainless steel

Core and plugnut               Stainless steel

Core spring                         Stainless steel

Seals                                   NBR

Top disc                              PA

Disc holder                          POM

Cartridge (low power)          Welded, packless AISI 430

Seat                                     Brass

Seat insert                           POM

Shading coil                        Copper

Rider rings (low power)        PTFE (NF/WSNF solenoids only


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