Check valves are proven components that allow media to flow in only one direction and prevent backflow in the opposite direction — similar to diodes in electrical applications. For years, the engineers at Bucher Hydraulics based in Dachau, Germany, have continuously optimized this unobtrusive component, which is often concealed inside hydraulic blocks.
For instance, the company’s RKVG and RKVE ball check valve series have shown their durability and usefulness in tough applications involving construction and agricultural machinery, as well as in countless industrial settings.
Bucher Hydraulics has now added valves in sizes 04 to 16 and thread sizes G1/8” to G3/4” in a shortened design to complement its range. According to the firm’s engineers, it’s in response to shrinking installation spaces in modern machines and systems.
Shorter and compatible
The new, compact ball check valves, the RKVE-KB and RKVG-KB series (KB = compact design), are between 2 and 3 mm shorter than standard versions and are an excellent solution for the space savings increasingly requested by customers. (The letters E and G indicate the flow direction, with E variants blocking flow in the screw-in direction and G variants blocking flow in the opposite direction.)
The valves fit market-standard cavities with 118° tip angle (REG-O5-E/REG-05-G). This means that valves from previous series and from other manufacturers can usually be replaced without difficulty.
Regardless of flow direction, only one tool is required for installation, reducing tooling costs. Both new KB variants offer a maximum operating pressure of 350 bar. The RKVE-KB valves open at a pressure of 0.2 bar and allow flow rates of up to 210 l/min. The RKVG-KB variant with the opposite flow direction is available with an opening pressure of 0.2 bar and a maximum flow rate of 170 l/min.
Prices for the short-design valves match that of standard designs and are on par with that of competing products, according to company officials. However, their quality and design ensure lower total cost of ownership — typically a much more significant expense for most users. The valves’ high reliability over long periods considerably reduces repair and maintenance requirements and expensive downtime.
Customized adaptations can easily be provided, thanks to Bucher’s Dachau Global Competence Center for check valves. In-house development and production ensure a high level of expertise in all aspects of these components. In addition to the standard product series available in stock, the company also provides special solutions for non-standard industrial and mobile applications, which are developed in close cooperation with customers.
A modular system ensures quick development of these products at marketable/economical prices. The product range covers screw-in and slip-in check valves, including the new short series, as well as surface-mounted check valves in SAE design. Application-oriented system solutions in which several check valves are integrated into one block for use in power units, municipal vehicles, and agricultural and construction machinery are also available. The Bavaria-based experts provide customer support right through to commissioning and joint tuning of the machine.
Another milestone in check-valve development for the Competence Center involves RKVE-VD valve series (VD = improved flow). The engineering team revamped previous check-valve designs to increase flow rates up to 50% compared to the standard version, all while maintaining the same pressure differential. This not only saves energy, but in many cases it also enables the use of smaller nominal valve sizes. At the same time, it lowers costs and requires less installation space. The valve body and seat are press-fitted together and, like the ball, are hardened. All valves are endurance-tested.
Instead of the typical soft seal, the new Bucher ball check valves use a metal cutting lip. This makes the valves suitable for use across a much wider temperature range. Plus, without sensitive sealing materials, the valves can handle a greater variety of media, such as gas or air. Stainless-steel valves are available for applications with media that cause rust. In general, the Bucher Hydraulics ball check valve is particularly insensitive to contamination — which is especially beneficial for mobile and agricultural machines. Even in the standard design, the valve seat, ball, and body are hardened.
In addition, all RKV valves are particularly energy efficient. As a member of the Blue Competence sustainability initiative of the mechanical and plant engineering industry, this has been a top priority for Bucher Hydraulics for many years. Only products that meet specific environmental criteria qualify for the “ECOdraulics” Bucher label. The ball check valve series, which features a low ΔP loss while providing high flow rates, measure up.