Solenoid valves - there's one for every occasion
Kelly Booth, solenoid valve specialist at Bürkert UK, looks at the various different valve types and their suitability to diverse applications.
Solenoid valves perform an essential task in the control of fluids and gases and the basic design has been refined over the years to allow them to be utilised in a wider range of applications. Modern fluid control systems present a number of challenges that require the correct design of solenoid to achieve a reliable and efficient control process.
On the face of it, selecting a solenoid valve appears to be a simple enough decision, however, making the right choice requires an in-depth knowledge of the process under control as well as expertise in the materials and designs available. With such a vast range of applications, it is important to match the correct design to each situation.
The first and most obvious characteristic of a solenoid valve is to determine whether it is direct acting or pilot operated. With a direct acting solenoid valve, the action of the solenoid plunger directly opens or closes the orifice. This type of solenoid is required when there is no line pressure to maintain the valve in the desired position.
A normally closed (NC) version will use a spring to keep the valve closed until the solenoid is energised and the coil will lift the plunger against the spring force to open the valve. Conversely, a normally open (NO) design uses the spring to keep the valve open allowing the media to flow until the solenoid is energised.
In the pilot operated design, there is a pilot and bleed orifice that uses line pressure to operate the main valve. When the solenoid is energised, the coil opens the pilot orifice and relieves pressure from the top of the valve piston or diaphragm to the outlet side of the valve. This results in an unbalanced pressure, lifting the piston or diaphragm off the main orifice. 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, which together with spring assistance, closes the valve. Pilot operated solenoid valves require a minimum pressure differential across the valve to keep them open or closed and therefore they can only operate with a suitable upstream pressure differential and do not operate at zero pressure. Pilot operated solenoid valves can provide high flow rates at high pressures with lower power consumption.
The armature design should be carefully considered with relation to the media that is being controlled. Pivoted armatures allow the use of a media separating diaphragm which enables the valve to be used in applications involving corrosive, contaminated or aggressive fluids. This style of valve can be easily mounted in a manifold and, unlike the plunger type, the 3/2-way version has all three ports in the same plane.
An alternative design is the rocker armature which is often used in microfluidic applications where small dead volumes and flush-ability are of prime importance. The compact design, combined with the small and efficient coil, enhance the suitability for aggressive or ultra-pure media. These attributes also make the design suitable as a pilot for pneumatic control valves in both hazardous and non-hazardous areas.
The flipper design uses a vertical armature that moves a flexible sealing system between two opposing seats. Bürkert has developed this principle for microfluidics with the possibility of using a valve that is only 4.5mm wide. Again the compact design and encapsulated sealing make this type of solenoid valve suitable for applications involving both aggressive and ultra-pure media.
Selecting the most appropriate solenoid design for an application will ensure the most efficient process control; choosing the correct materials for the various components will ensure reliable service. Bürkert has considerable experience and expertise in testing and specifying both metallic and synthetic materials for solenoid components.
Based on the chemical composition and temperature of the media to be controlled, application engineers can provide the most suitable design of solenoid valve for any application. A wide range of materials can be used for the various seals and diaphragms within the valve and making use of the available advice can deliver the most cost effective solution. These include PVC-HT, PP/PE, PA, PTFE, PVDF, PPS and PEEK, depending on the acidity, alkalinity or temperature of the medium.
Many applications involve complicating factors such as high pressure, explosive atmospheres or special regulatory requirements. Bürkert aims to simplify the task of specifying solenoid valves for all applications, even those with special requirements. With designs capable of operating up to 250 bar it is still possible to select the most appropriate sealing material.
For applications involving potentially explosive atmospheres safety is of the utmost importance and therefore a number of solenoid valve designs are available with a range of certifications including ATEX. With over 25 years of experience in designing and manufacturing fluid control components for hazardous areas, Bürkert also participates in the various standards committees in order to keep up to date on the latest developments.
The solenoid valve remains an essential component of most fluid control systems and as such it needs to be properly specified if it is to deliver reliable and efficient service. Design and application engineers are always looking to improve existing designs and incorporate the latest technology for the benefit of the end user. Whether designing a new system or simply replacing an existing component, making use of the considerable expertise and experience available today is a sensible option.
Other News from Burkert Fluid Control Systems

Latest news about Hydraulic components
- Eaton launches cost-competitive Winner PTFE hoses for demanding applications
- Flexicon extends its liquid-tight conduit system range with UL and CSA certification
- Helping OEMs bring new machine features to market
- Eaton launches a new Multiplate system enabling faster and simpler connectivity for Flat Face Series Quick Disconnect Couplings
- Moog Modular Electrohydrostatic Actuation System (EAS) combines the best of two worlds
- Particle contamination monitor performs test procedure in under 90 seconds
- Bonomi UK launches new website and digital catalogue
- Eaton’s new CMT mobile valve section increases design flexibility
- Very high speed solenoid valves increase semiconductor production output
- Engineering Expertise from Eaton Hydraulics UK keeps the blades turning
- Dispense pumps meet the growing fluidic challenges of evolving medical-IVD instruments
- Elesa launches new FH modular coolant hose system
- Air bleed orifice improves efficiencies in hydraulic systems
- Essentra Components produces free guide to hydraulic hose protection
- Hycrocam hydraulic bolt tensioners remove uncertainty from couplings
- Bürkert solenoid valve tackles dezincification and water hammer
- Thermoplastic hydraulic hoses and fittings designed to work together, enabling safe and effective fluid conveyance
- 5 facts about hydraulics that may surprise you
- Money saving fallacy of hose re-ending
- Miniature solenoid valve offers high flow and low leakage
- Moog and Voith to form strategic partnership
- Charting the right course to efficiency in the marine industry
- Greater flexibility for high pressure applications
- Hydraulic handbook is packed with useful data
- Filtermist to demonstrate how it helps workers ‘Go Home Healthy’
- Elesa level monitoring accessories and labelling provision simplify hydraulic systems
- VHS appointed Bosch Rexroth integrator
- Absorbing water from hydroscopic oils
- Eaton Hydraulics invests in state-of-the-art training facility
- Solenoid valve key to brake innovation
- Stauff demonstrates innovations in hydraulic components and accessories at Fluid Power & Systems 2018
- Hose selection is critical to minimising fire risk
- Latching solenoid valve saves energy
- VHS Hydraulic Components acquires Nielson Hydraulics
- Hose combines high pressure with long cycle life
- Hydraulics will run and run with proper servicing
- Plugs are designed to seal cross port passageways
- Lee Products publishes 9th edition of EFS handbook
- A match made in heaven
- Bosch Rexroth Hydraulics Roadshow is hailed a huge success
- New ATEX hydraulic accessories from Elesa
- Elesa breather caps and level indicators hit the mark for Sarum Hydraulics
- Best practice is vital in hydraulic fluid selection
- In-line wash flow safety screens take filtration to a higher level
- How to control hydraulic flow rates more efficiently
- Staying safe with hydraulic hoses
- Bespoke test rig installation completed
- Lee restrictors keep the electricity on
- Miniature inert solenoid pumps offer flexibility
- Gas charging test kit product range
- The risks of outdated separators
- Controllers for precision hydraulic motion
- The importance of security in today’s connected world
- Manufacturer keeps UK hydraulics industry alive in Singapore
- Tom Parker introduces the FasTest range
- Pressure Hydraulics Cork recognised as Ireland’s first Bosch Rexroth Authorised Training Centre
- Liquid cooling for enclosures
- Slots versus holes improve flow through safety screens
- Ultra-compact, energy-efficient solenoid valves save space and reduce weight
- Brammer announces new partnership
- Hydraulic Components catalogue
- Hydraulic hose assembly
- Reliable tube connection system for extreme conditions
- The show goes on for RSC thanks to hydraulic cylinders
- Trio of success caps off growth year for hydraulics specialist
- Top ten tips – oil analysis
- Vestas choose Bosch Rexroth for hydraulic power unit
- Connectors: clean break, flat face or double shut off?
- Report highlights maintenance failings in UK manufacturing
- The hydraulic fluid 'laboratory in a suitcase'
- Ultra-miniature solenoid valves save space and use less energy
- Robust, lightweight PEEK safety screens
- Strainers provide coarse level filtration without pressure drop
- Big savings in oil filtration for aerospace
- Investment to meet growing demand
- Failure to conduct oil checks a "major cause" of hydraulic failure
- New connector for sterile processes
- Miniature inert solenoid valve protects sensitive fluids
- Miniature, chemically inert stepper dispense pump
- Strainers provide coarse level filtration without pressure drop
- Liquid cooling for enclosures
- Industry 4.0 - concepts and practical solutions
- Miniature medical grade check valve ideal for plastic manifolds
- BFPA and BCAS form UK Motion Control Alliance
- A 'hands-on' opportunity in Telford
- Miniature servo actuators bring high power density to Formula 1
- Stauff UK and GR Motosport unveil Connect Academy
- High pressure flow restrictors for critical applications
- Moog delivers tyre coupled simulation system to Mazda
- Neilson Hydraulics goes back to new with Bosch Rexroth
- Piedrafita selects Moog for fatigue test system
- Bosch Rexroth launches oil analysis service to reduce machine downtime
- Oil contamination identified as a major cause of machinery failure
- Miniature burst plugs provide over-pressure protection
- New gear pump design offers near silent forklift operation
- Eaton's low-temperature hydraulic hose serves mining and construction
- Hydraulics
- Bosch Rexroth opens new service and training centre in Wakefield
- Accurate positioning and adjustment of equipment
- Tom Parker brings new range to the UK market
- Precision microhydraulic components solve critical problems of size and weight
- Miniature electro-fluidic systems from Lee Products
- Bosch Rexroth gives legs to walking robot
- A short guide to selecting quick release fluid connectors
- Bosch Rexroth expands into filtration market
- Electro fluid systems guide
- New EFS handbook published by Lee Products
- UK sales and service partner for Sauer Danfoss
- NACE compliant safety screens for extreme applications
- Ultra-fine safety screens are robust
- Fluid Control
- Safe fluid power
- Bright future ahead as Bosch Rexroth breaks ground in Wakefield
- Configure hydraulic solutions
- Inert solenoid pump sets new standards of design flexibility
- Gas springs operate in conjunction with electro-hydraulic lifting system
- The business benefits of upgrading hydraulic systems
- Equipment for use in hazardous areas
- The essential companion throughout hydraulics and pneumatics industries
- Hydraulics for subsea operations
- Bosch Rexroth completes Hägglunds Acquisition
- Safety holds the key to improved business performance
- Compact piston type open circuit pumps
- Hydraulics distribution
- Independent, highly dynamic linear axis
- Multiple pumps with reduced overall length
- Eaton's hydraulics help free the Chilean miners
- Dampers key in support vessel safety system
- Fluid connectors
- Keeping your fluids clean
- Atomising nozzles deliver precise spray pattern
- Parker plays crucial role in military projects
- Hydroscopic breathers boost performance
- New hydraulic power packs
- Going with the flow on green energy
- Oil level indicators in brass and stainless steel
- Replacement filters enhance profitability
- Edbro success in tilt test trials
- Parker distributor BSP Hydraulics expands into marine sector
- Fluid control catalogue highlights Burkert's wide range
- Micro nozzles for delicate washdown applications
- Compact, light valve for high pressure charging
- Hydraulics and electronics combine in stored energy management system
- New handbook for hydraulic and pneumatic components
- An engineering guide to miniature fluid control components
- Connector approved to key hydraulic standard
- Couplings for medical applications
- BFPA hosts major standards meeting
- Microfluidics
- Miniature orifice saves weight and space
- Hydraulic Fluids
- High speed solenoid valves for micro dispensing
- Highly accurate screened orifice for medical applications
- Leak-free plugs handle high pressures
- Lightweight valves ideal for OEM flow switching
- Miniature solenoid valve sets new standards
- High pressure cartridge screens block rogue contaminants
- Micro inert valve needs less space and uses less power
- Micro-dispense nozzles for optimum system flexibility
- Miniature check valve for harsh duty applications
- Miniature insert orifice saves weight and space
- Miniature pumps help make a smaller machine, better
- Miniature relief valve ensures zero leakage
- Miniature shuttle valve ideal for hydraulic isolation
- Power generation Chek valves are field serviceable
- VHS solenoid valve manifold ideal for flow injection tasks
- Zero leak check valves suit critical flow control systems
- Control two circuits from just one hydraulic source
- End caps protect and isolate
- Rugged safety screens handle twice the pressure
- Cleaner, faster, smarter, safer drum connections
- Innovative connectors simplify seal test line construction
- Steel cam couplings offer quick release
- Cylinders designed to boost productivity
- New 90 litre bi-directional poppet valves
- Logic element combines flexibility with performance
- New premises for Hydrastore marks expansion
- When is a repair not a real repair
- Reducing the hazards of analysis
- Hydraulic power for innovative milking systems
- Parker brings particle analysis out of the lab
- Pump design offers big benefits in stationary hydraulic applications
- Helping to minimise environmental damage
- Hydraulics performs in the leisure industry
- That sinking feeling - with complete digital accuracy
- Two-stage breather cap
- High performance filters
- How to capitalise from your component breakdowns
- Bosch Rexroth lands its biggest ever order
- Parker Hannifin launches its cylinder repair service
- Taking sides on suction and return filtration
- Hydraulic rams and block cylinders
- Needle type flow control valves
- Absolutely leak-free larger couplings
- High pressure plug for venting applications
- Compact valve protects in the event of sudden failure
- Leak-free connections speed endoscope reprocessing
- Bosch Rexroth takes electrohydraulics to the next level
- Valves meet needs for higher flow rates
- The smallest solenoid valve in the world
- Couplings make fluid transfer simple and safe
- Proportional flow control valve
- Hydraulics power two Iraqi bascule bridges
- Multi-function screw-in valve