Safe disconnection of torque or safe disconnection from the energy supply.
Implementing functional safety according to ISO 13849 is one of the biggest challenges in mechanical engineering. Especially in hydraulics, complex safety assessments, custom designs, and elaborate validations often lead to long project durations and high costs. Therefore, solutions are needed that radically simplify the process without compromising safety. This is precisely where the new Safe Torque Off (STO) Manifolds STOM from Bosch Rexroth come in – a groundbreaking, standardized solution.
STO Manifolds (STOM) are the out-of-the-box solution for efficient implementation of machine safety in hydraulics. How do these standard components enable safety at the highest level without driving up engineering effort? Four questions, four clear answers.
Can functional safety in hydraulics be implemented quickly, easily, and reliably?
Of course. With our Safe Torque Off (STO) Manifolds STOM.
These manifolds eliminate the complexity normally associated with complying with functional safety requirements according to ISO 13849. Instead of investing in time-consuming, custom engineering, complex assessments, and expensive validations, you simply select a suitable variant from our standardized portfolio.
The STOM series offers:
- Pre-configured and pre-validated safety functions up to the highest safety level Cat 4 PLe – certified by the DGUV (external testing body for machine safety).
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Easy selection based on four parameters:
pressure, flow rate, safety level, and required functions. - Comprehensive documentation including validation calculations and installation instructions.
The decisive advantage:
The immense effort for project planning, design, assembly, and safety assessment is drastically reduced. Users report a significant reduction in safety engineering time compared to custom designs.
Is it possible to integrate important safety functions like STO, SDE, and SLS into one block?
Absolutely. The STOM Manifold was developed to combine the three central hydraulic safety functions in a single, compact component:
- Safe Torque Off (STO): A two-channel, position-monitored shut-off ensures the safe disconnection from the hydraulic power supply and a leak-free shutdown of entire machine areas or systems in less than 300 ms.
- Safe Decompression (SDE): After shutdown, the downstream pressure is controllably relieved. Dual bypass valves ensure accelerated decompression.
- Safe Limited Speed (SLS): The same bypass circuit can be used for pre-compression. This minimizes switching shocks when opening the main valves, which increases component life, reduces noise, and enables safe setup operation.
This high function integration reduces the need for external components and piping, which increases the clarity and reliability of the overall system.
Do the manifolds guarantee maximum plant safety even under high pressures?
Definitely. The STOM solutions are designed to ensure fast and safe shutdowns even under demanding operating conditions.
In most operating states, measured closing times of less than 300 ms are achieved. A practical test, for example, demonstrated a closing time of less than 250 ms at 75 bar system pressure. The higher the system pressure, the faster the control block closes.
These fast reaction times are crucial to minimize hazards in an emergency and maximize plant safety. Reliability is based on proven Bosch Rexroth valve technology, optimized for the requirements of functional safety. A galvanized surface also ensures long-lasting corrosion protection.
Can the effort for commissioning, maintenance, and spare parts management over the entire life cycle of a machine be minimized with the STOM solution?
Indeed. Through consistent standardization. Selection is simply done via a material number from the datasheet.
Since all nominal sizes use identical electrical control, commissioning and spare parts management are significantly simplified.
Compatibility with mineral oils (HLP) and flame-resistant fluids (HFC, HFDU) also enables flexible retrofitting in existing systems. From design to installation and operation to maintenance – the STOM manifolds reduce complexity and life cycle costs, minimize production interruptions, and thus increase productivity.
Comparison: STOM vs. Custom Development
| STO Manifolds (STOM) | Custom design, engineering, and implementation of the hydraulic solution |
|
|---|---|---|
| Engineering Effort | Minimal through standard selection | Very high, custom design |
| Safety Assessment | Pre-engineered & pre-validated | Complex, time-consuming, high risk |
| Time to Commissioning | Significantly shortened | Months of development & validation time |
| Function Integration | STO, SDE, SLS in one block | Mostly separate components & piping |
| Project Risk & Costs | Low due to tested standard solution | High due to complexity and individual validation |
The STO Manifolds STOM make the implementation of functional safety in hydraulic systems simpler, faster, and more reliable. They combine the highest safety requirements with the efficiency of an out-of-the-box solution. As a standardized, pre-validated component, the STOM blocks reduce engineering effort, accelerate commissioning, and create planning certainty over the entire life cycle. Typical Bosch Rexroth.
Technical Documentation
For simple project execution, comprehensive documentation and an operating manual are available.
The selection of the appropriate STOM variant is straightforward using the material number from the data sheet.
Want to rethink functional safety?
Absolutely! Contact our sales department now.
Glossar
STO (Safe Torque Off)
SDE (Safe Decompression)
Safe and controlled depressurization of system parts.
SLS (Safe Limited Speed)
Safe limitation of speed, often used for setup operation.
ISO 13849
The guiding standard for the functional safety of safety-related parts of control systems.
Cat 4 PLe
The highest control category (Category 4) and the highest Performance Level (PL e) within the ISO 13849 standard, which describes the lowest probability of failure.