Functional safety 'out of the box'

New standardized STO manifolds for new designs and retrofits increase installation safety in metallurgy, in presses and test benches according to ISO 13849, for example.

• Modular, standardized design reduces engineering and integration times.
• Energy-efficient operation with the latest high-flow logic valves.
• Closing times below 300 ms, maximized volume flow that can be decompressed.

With the new STO manifolds, Bosch Rexroth presents a pioneering turnkey solution for the efficient implementation of functional safety in hydraulic systems according to ISO 13849 up to the highest control category Cat 4 PLe. The manifolds can be used as a shut-off function for complete machines or for system components in all sectors. The standardized design with preferred components enables significant time savings compared to in-house development. Innovative components such as the new generation of LC2A logic valves maximize performance and increase energy efficiency. Depending on system pressure and oil viscosity, closing times of less than 300 ms can be achieved.

In hydraulically driven presses, test benches and metallurgical plants such as rollers or extrusion presses, functional safety according to the ISO 13849 Machine Safety Directive is an important aspect for both new designs and modernizations. The standard defines safety functions such as the safe torque off or safe disconnection of the hydraulic supply (Safe Torque Off, STO), the safe depressurization of pressurized lines (Safe De-Energizing, SDE) or the safe limitation of volume flow during commissioning(Safe Limited Speed, SLS).

With the new STO manifolds, machine manufacturers and system integrators can rely on a standardized solution to implement the hydraulic partial safety functions STO, SDE and SLS up to control category 4 with minimal time commitment. The time normally required for project planning, design, installation and especially safety assessment is significantly reduced. Detailed installation instructions and documentation also contribute to this.

The STO portfolio offers three basic variants for different requirements: The highest safety level enables a double position-controlled closure in series (STO) according to Cat 4 PLe. The integrated bypass can also be used to implement an SDE and SLS function in the same control category. If the SLS function is also used for precompression, impacts due to switching and pressure spikes can be reduced when opening the main valves. This has a positive effect on noise levels and component life.

The second variant offers the same range of functions for Cat 3 PLd, with bypass functions validated via an integrated pressure sensor. This eliminates the need for additional equipment with pressure sensors in the system. The third basic variant without bypass meets the requirements for a redundant shut-off function (STO) according to Cat 4 PLe.

The new hydraulic shut-off manifolds are suitable for both new systems and modernizations. In addition to mineral oil-based hydraulic fluids (HLP), hardly flammable fluids (HFC and HFDU) can also be used. The surface of the STO-Manifolds is galvanized for long-term corrosion protection.

With a nominal volume flow of up to 1500 l/min and a maximum operating pressure of 315 bar, STO-Manifolds achieve measured closing times of less than 300 ms under most operating conditions, depending on system pressure and oil viscosity.

Easy selection and ordering

The appropriate STO-Manifold variant can be easily determined and ordered with only four values: pressure, volume flow, achievable performance level (control category) and fluid. The standardized design with a uniform drilled base block significantly reduces delivery time.

STO-Manifolds are available in sizes 20 to 40, with sizes 32 and 40 achieving maximum performance and high energy efficiency thanks to the latest generation LC2A high-performance logic valves. All variants both provide a leak-free seal in the main line from P1 to P2. Bosch Rexroth also offers ctrlX CORE control units and ctrlX SAFETY safety solutions for the new STO-Manifold portfolio.