Solenoid Valves

Latching Solenoid Valve.

Latching or Bi-stable solenoid valves are typically available from a wide range of body materials such as Plastic, Brass and Stainless Steel and a range of port connection sizes from 1/8", 1/4",3/8",1/2",3/4",1",11/4",11/2" and 2" BSP or NPT thread or even with flanged end connections such as PN16RF or ANSI150Lb. Latching valves are found and used to suit most media applications including air, vacuum, water, steam, diesel fuel, petrol, oil and even slightly aggressive media such as pure or de-mineralised RO water and slightly acid or alkali liquid or gas media.

How do latching solenoid valves work.

Latching or bi-stable 2/2 way solenoid valves require only a short electrical power pulse to change the solenoid state from open to closed or visa versa. Unlike standard 2 way solenoid valves that require a continued electrical supply to change the valve state.

Typically a latching solenoid valve also known as a bi-stable solenoid valve will have a semi permanent magnet within the solenoid armature or core tube. A short millisecond electrical power pulse of either 6vdc, 12vdc or 24vdc depending on the choice solenoid coil (direct current only) will activate the semi permanent magnet keeping the valve in the open position allowing the flow of media. By reversing the polarity of the electrical signal (i.e. if terminal 1 was positive and terminal 2 negative simply swap terminal 1 to negative and terminal 2 to positive) this in turn will remove the magnetic charge from the semi permanent magnet allowing the solenoid valve to close and remain closes stopping the flow of media.

What types of latching solenoid valves are available?

There are two main types of bistable solenoid valve, direct acting or pressure / servo pressure assisted.

A direct acting or assisted lift latching solenoid valve does not require any guaranteed pressure differential to operate (i.e. pressure difference between inlet and outlet port), making them ideally suited to low pressure, gravity feed, vacuum and closed loop pipe systems. Keep in mind larger solenoid valves typically 1/2" upwards will probably have pressure limitations and small miniature solenoid valves under 1/2" will have probably have flow limitations. 

A pressure or servo assisted piston or diaphragm latching solenoid valve utilises the pressure differential (pressure difference across the solenoid valve) via an internal pilot circuit to control the position of the main sealing diaphragm or piston making them ideally suited for high flow, high pressure and open to atmosphere applications. Keeping mind this solenoid valve design relies on a guaranteed pressure difference typically more than 0.5 bar for the valve to function correctly.

How do I choose the correct latching solenoid valve?

Choosing the correct bi-stable solenoid valve is of paramount importance and all rests on the application in hand and all working parameters. you need to know:

1. Pressure:

The maximum and minimum pressures i.e. 0 to 3 bar, 0 to 10 bar, 0.5 to 10 bar, 0.5 to 25 bar, other measurements such as kilogram force per square centimetre, Kpm etc. are normally acceptable as these can be converted.

2. Flow rate

What flow rate is required for your application ideally in litres per minute, but other measurements such as cubic meters an hour etc. will suffice as these can be converted.

3. Pipe size

What port size you require or pipe size either 1/8", 1/4",3/8",1/2",3/4",1",11/4",11/2" and 2" for thread or DN10,DN15,DN20,DN25,DN32,DN40 or DN50 flange.

4. Connection type

What connection type you require such as BSP, NPT or Flange PN16, ANSI150Lb, JIS10K etc.

5. Media type

What is the media being controlled through your solenoid valve i.e. air, water, vacuum, oil, diesel etc., this will provide which compatible body and seal materials can be used.

6. Temperature

What is the maximum and minimum ambient AND media temperature expected for the application. This provides additional information for the seal and body material and insulation class of coil to be used.

7. Voltage and power supply:

What is the control voltage required, typically this is limited to 6 volt, 12 volt and 24 volt DC only, AC cannot be used as this is an oscillating current. Additionally the limitations of the power supply measured in Amps or Watts as power supplied from a transformer will be much greater than power available from a battery and solenoid coils are available with a range of power consumptions depending on size, pressure and operation from 2.2 watts through to 18.5 watts or more.

See below the more common ranges of 2-way solenoid actuated latching brass, stainless and plastic bistable valves including direct acting / assisted lift and pressure assisted diaphragm and piston bi-stable valves.

Read more about 6 to 24 volt bi stable / latching valves here...

Latching solenoid valve for mains water 

Plastic latching solenoid valve for mains water.

1/4" BSP male 3115BB-6vdc

1/4" BSP female 3105BB-6vdc

3/8" BSP male 4115BB-6vdc

3/8" BSP female 4105bb-6vdc

1/2" BSP male 5115bb-6vdc

3/4" BSP male 6115bb-6vdc

15mm push fit 1175bb-6vdc

Pressure: 0.2 to 10 bar

Voltage: 6vdc up to 9vdc up to 12v

Media: water

Common applications: Urinal flushing systems, vending machines, water appliances.

bi stable plastic solenoid valve

Delrin (POM) plastic latching solenoid valve

Port: 3/8,1/2,3/4,1,11/4 or 11/2 BSP or NPT thread

Orifice: 15mm,15mm,20mm,25mm,35mm or 35mm

Seals: NBR, Silicone, EPDM, FKM, FFKM

Pressure: 0.5 to 10 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, RO + pure water, slight acid or alkali

Options: Silver Shading Ring

Common applications are salt water systems, desalination plants, water treatment, hygienic cleaning machines

miniature latching solenoid valve

Brass latching solenoid valve high pressure

Port: 1/8 or 1/4" BSP or NPT thread

Orifice: 1.2mm,1.6mm,2mm,3mm,4mm or 5mm

Seals: NBR, Silicone, EPDM, FKM, PTFE, FFKM

Pressure: 0 to 42 bar

Voltage: 12v or 24vdc

Media: air, water, light oil,vacuum, fuel

Typical options: Manual Over Ride, Silver Shading Ring

latching solenoid valve miniature

Brass latching solenoid valve direct acting

Port: 1/8,1/4,3/8 or 1/2" BSP or NPT thread

Orifice: 3mm,4mm,5mm,6mm or 8mm

Seals: NBR, Silicone, EPDM, FKM, PTFE, FFKM

Pressure: 0 to 3.5 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel

Typical options: Manual Over Ride, Silver Shading Ring

 

latching solenoid valve brass zero rated

Brass latching solenoid valve zero rated

Port: 3/8,1/2,3/4,1,11/4,11/2 or 2" BSP or NPT thread or flange

Orifice: 15mm,20mm,25mm,35mm,35mm or 50mm

Seals: NBR, Silicone, EPDM, FKM, FFKM

Pressure: 0 to 3.5 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel

Typical options: Manual Over Ride, Silver Shading Ring

 

latching solenoid valve stainless miniature

316 stainless steel latching direct acting solenoid valve high pressure

Port: 1/8 or 1/4" BSP or NPT thread

Orifice: 1.2mm,1.6mm,2mm,3mm,4mm or 5mm

Seals: NBR, Silicone, EPDM, FKM, PTFE, FFKM

Pressure: 0 to 42 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel, RO + pure water, slight acid or alkali

Typical options: Manual Over Ride, Silver Shading Ring

 

latching stainless mini solenoid valve

316 stainless steel latching direct acting solenoid valve

Port: 1/8,1/4,3/8 or 1/2" BSP or NPT thread

Orifice: 3mm,4mm,5mm,6mm or 8mm

Seals: NBR, Silicone, EPDM, FKM, PTFE, FFKM

Pressure: 0 to 3.5 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel, RO or pure water, slight acid or alkali

Typical options: Manual Over Ride, Silver Shading Ring

 

latching stainless solenoid valve

316 stainless steel latching solenoid valve zero rated

Port: 3/8,1/2,3/4,1,11/4,11/2 or 2" BSP or NPT thread or flange

Orifice: 15mm,20mm,25mm,35mm,35mm or 50mm

Seals: NBR, Silicone, EPDM, FKM, FFKM

Pressure: 0 to 3.5 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel, RO + pure water, slight acid or alkali

Typical options: Manual Over Ride, Silver Shading Ring

latching solenoid valve for steam mini series

Brass latching steam high temperature solenoid valve

Port: 1/8,1/4" or 3/8" BSP or NPT thread

Orifice: 3mm,3mm or 4mm

Seals: PTFE

Pressure: 0 to 4.9 bar

Voltage: 12vdc or 24vdc

Media: air, water, light oil, vacuum, fuel, steam

Common options: Manual Over Ride, Silver Shading Ring

latching steam solenoid valve piston series

Brass latching steam pilot operated solenoid valve high pressure

Port: 3/8,1/2", 3/4",1",11/4",11/2" or 2" BSP or NPT thread or flange

Orifice: 15mm,15mm,20mm,25mm,35mm,35mm or 50mm

Seals: PTFE

Pressure: 0.5 to 12 bar steam 20 bar air/water

Voltage: 12vdc or 24vdc

Media: air, water, light oil, fuel, steam

Common options: Manual Over Ride, Silver Shading Ring

high pressure latching solenoid valve

Brass latching extreme high pressure solenoid valve

Port: 1/8 or 1/4" BSP or NPT thread

Orifice: 0.7mm or smaller

Seals: PTFE with NBR, FKM or EPDM

Pressure: 0 to 300 bar steam 20 bar air/water

Voltage: 12vdc or 24vdc

Media: carbon dioxide, Inergen fire fighting systems gases.

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