Wandfluh has completely reworked its range of NG10 spool valves and has launched a new portfolio of high-performance products onto the market. They feature an optimized cast body, which has improved performance-to-weight ratio, ΔP values, and maximum flow.
Direct-operated valves
1. Wandfluh’s WDMFA10 solenoid spool valve.
2. WVPFA10 proportional spool valve.
3. WVBFA10 pilot-operated explosion protection valve.
The range is based on a cast body design, which is used both for direct-operated and pilot-operated valves. All valves in the range are capable of system pressures to 350 bar and some can operate at levels to 420 bar.
The direct-operated version can control 160 lpm and with a very low ΔP. To reduce pressure shocks in sensitive systems, a soft shifting spool valve has been developed. By adjusting damping orifices, the valves can be individually optimized for an application. If a very sensitive flow control volume is a key design element, then a proportional spool valve would be an appropriate choice. These proportional valves with very low hysteresis can control the volume flow up to 100 lpm by means of flow simulation during design, and flow optimization. Flow forces in the valve can be kept low which has a positive effect on the flow rate in the upper pressure range.
Great emphasis was placed on the symmetrical design of the valve. As a result, valves in both operating directions have the same characteristics. Various electronic control devices are adapted to solenoids to allow for highly precise operation. Precise control is achieved through a superimposed dither signal and a pulse width modulation (PWM) power amplifier. Closed control circuits can also be developed which are integrated through fieldbus interfaces with machine control systems.
Pilot-operated valves
The cast body of the compact version of the pilot-operated valves is pilot operated by a compact NG4 spool valve. This greatly reduces installation space and enables lower solenoid power to be utilized.
With the switching valves, the power of the solenoids is reduced from about 30 W (NG6) to 20 W. The maximum switching capacity increases to 160 lpm with a low ΔP. At less than 4 kg of weight, the pilot-operated spool valve is one of the lightest valves on the market. It is even lighter than the direct-operated NG10 valves.
The pilot-operated proportional valve is fitted with an NG4-Mini pressure control valve, which is also one of the most compact valves on the market. The pilot control builds up to 40 bar to control the main valve up to 200 lpm. With all the Wandfluh pilot-operated valves, users can decide whether they want to use the control pressure externally or internally from inside the valve.
Custom designs
The valves are fitted with exchangeable slip-on coils. In addition, the solenoid coils are available with different types of connectors, electrical power and surface treatments. All the products are available in a range of special variations, for explosion protection, increased corrosion protection, switching position monitoring, or low-temperature applications.
The pilot control of the explosion-proof version is based on NG4-Mini Valve technology, which is available in the standard range of switching valves. This modular system gives the entire NG10 range optimum flexibility, with the same high performance data as valves without explosion protection.
Explosion protection valves are often used in applications with low ambient temperatures. This means that versions of the NG10 explosion protection valves can be built for temperatures as low as –40° C.
The new NG10 range also includes explosion protection proportional functions. This high-performance valve can be used in applications with large flow volumes and high operating pressures in market applications such as industrial, marine, mobile, forestry, energy, and oil and gas that must be precisely controlled.
The new generation of NG10 spool valves guarantees maximum flexibility and high performance in a compact package.
Wandfluh of America Inc.
wandfluh-us.com
Filed Under: Fluid Power World Magazine Articles, Valves & Manifolds
