Solenoid valve function

Normally Closed when de-energised :
solenoid valve opens when the coil is energised.

Normally Open when de-energised :
solenoid valve closes when the coil is energised.
2 way :
1 inlet + 1 outlet
open / closed « on & off »
de-energised energised
universal :
1 inlet + 1 outlet + 1exit
2 inlets + 1 outlet mixing
1 inlet + 2 outlets distribute

Operating and construction principles

  • 1. Solenoid

    It affects the electromagnetic strength, the overall design and the external tightness of the valve.


      the coil of the solenoid is mounted around a sealed tube in which slides a magnetic core. This core pulls/pushes the main plug/piston or pilot-plug of the valve. it is therefore "immerged" in the passing fluid. This design ensures external tightness. However, the valve must be mounted in an up right position. the coil is either protected by a metal cover or moulded in resin.


      The coil is incorporated in a fixed frame of laminated steel plates. When energised, the mobile magnetic core (of the same material as the frame) pulls/pushes the valve spindle and with it the main plug/piston or the pilot plug. This design requires an external dynamic sealing (stuffing box seal). This solenoid valve design always closes by spring return for safer tightness. It can be fitted to accept balanced plug. Laminated electromagnets may have double winding coil to reduce power consumption when holding.


      CA AC: 12, 24, 48, 110, 230, 380 V - 50 (& 60) Hz
      CC DC: 12, 24, 48, 72, 110, 125, 220 V
      : Atex II 2G / D – EExd IIC T2→T6 & II 2G EEx m II T4
      : Directive ATEX 94/4/CE
      Power consumption : Consumption at the rated voltage and a coil temperature of + 20°C, expressed in Volt-Ampere (VA) for AC voltages, and in Watt (W), for DC voltages.
      Operating factor : Percentage of time the solenoid may remain energised (most coils 100%).
      Insulation class : Maximum permissible temperature at the hottest point of the coil when energised, with an ambient temperature of + 35°C: Y/90°C, A/105°C, E/120°C, B/130°C, F/155°C, H180°C.
      Enclosure IP : guaranteed level of pro­tection - against solid, liquids or mechanical impacts – of the electromagnetic circuit by its enclosures (housing, cover, moulding etc.).

  • 2. Opening/closing principles

    Inlet pressure, difference between inlet/outlet pressures and the orifice of the valve are the main parameters to determine a best suitable opening/closing principle.


      The solenoid core is mechanically connected to the valve disc and directly opens or closes the orifice, dependent upon energisation or de-energisation of the solenoid. Operation is not dependent upon line pres­sure or rate of flow, and the valve will operate from zero to its maximum rated pressure.


      This valve is equipped with a pilot and (smaller) bleed orifice, and utilises the line pressure for operation. When the sole­noid is energised, the pilot orifice is opened and releases pressure from the top of the valve piston or diaphragm to the outlet of the valve. This results in an unbalanced pressure ­which forces the line pressure to lift the piston or diaphragm off the main orifice, thereby opening the valve. When the solenoid is de-energised, the pilot orifice is closed and full line pressure is applied to the top of the piston or dia­phragm through the bleed orifice, thereby providing a sealing force for tight closure.


      Hung type diaphragm or piston which is mechanically held open by the core and operates from zero to the maximum pressure rating.

  • 3. Solenoid valve with balanced plug

    Only on solenoid valves equipped with laminated electromagnet. The plug is balanced to avoid that its movement is countered by the surrounding fluid pres­sure. Different types of cons­truction can secure this ba­lance

    Simple balance on inlet pressure
    (seat diam. = diam.
    of the plug stem)

    Double guide/balance with an extended plug stem
    (seat diameter
    = the diameter of the plug stem
    = stem extension diameter )

    Double guide/balance
    with an extended plug stem and a balancing chamber on the inlet

Body, internals & seal materials


Brass 2,0402 Cu Zn39 Pb3 F37 (Zu) not suitable for aggressive medium
Cast Iron 0.6025 GG – 25 (FT-25) or flanged valve up to PN16 & neutral fluid
Sph. Gr .Cast Iron 0.7043 GGG – 40.3 (GS) for flanged valve up to PN25
Cast Steel 1.0619 GS - C 25 or flanged valve up to PN40, high temp. & neutral fluid
Red Brass 2,1096 Cu Sn Zn Pb7 where brass is not good enough
Stainless Steel AISI 316 Ti G-X7 Cr Ni Mo Ti 18 (10) fluids
Stainless Steel AISI 304 X 5 Cr Ni 18 9 for aggressive fluids
Stainless Steel AISI 430 F X 1 2 Cr Mo S 1 7 for plunger material
Aluminium 3.2162.05 AL Si 8 Cu 3 for neutral fluids and PN 16 body


Acrynitril – Butadiene – Rubber -10°C - +80°C Standard elastomer material for neutral fluids like air, water and oil.
Ethylen – Propylen ­ - Rubber -20°C - +130°C Elastomer for caustic solutions, acids of lower concentration, water, hot water and steam. Not resistant with oil and grease.
Fluor – Rubber -20°C - +180°C Resistant elastomer for high temperature, acids, bases, gasoline (petrol) and oils (synthetic oils). Not suitable with steam and hot water.
H-NBR -20°C - +150°C Elastomer for acids of lower concentration, oils and salt water.
Polytetrafluor – Ethylene (Teflon) -200°C - +200°C Non elastic thermoplastic material suitable for cryogenic and high temperatures.
Teca Peak -200°C - +300°C Similar to PTFE however more resistant to higher pressures and temperatures.


cylindrical or tapered
« mm Ø int. / mm Ø ext. »
« DN » PN10/PN16, PN 25 & PN 40 > PN40 NF, DIN, ASA, ANSI, etc.
Ø orifice
Diameter Nominal passage au siege « mm »
1/8" 5/10 /.
1/4" 8/13 /.
3/8" 12/17 /.
1/2" 15/21 DN 15 15 mm
3/4" 20/27 DN 20 20 mm
1" 26/34 DN 25 25 mm
1" 1/4 33/42 DN 32 32 mm
1" 1/2 40/49 DN 40 40 mm
2" 50/60 DN 50 50 mm
2" 1/2 66/76 DN 65 65 mm
3" 80/90 DN 80 80 mm
3" 1/2 90/102 DN 90 90 mm
4" 102/114 DN 100 100 mm
5" 127/140 DN 125 125 mm
6" 152/165 DN 150 150 mm
8" 203/219 DN 200 200 mm
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