Whether in the automotive, food & packaging, machine tool or general automation sectors, pneumatic applications with compressed air preparation are used throughout the industry where the operating pressure of a system must be vented for safety reasons. To guarantee employees a particularly high level of protection, SMC has developed the new VP546/746 series safety venting valve, which complies with a safety component in accordance with Machinery Directive 2006/42/EC Article 2c. Thus, the compact and modular 3/2-way solenoid valve prevents unexpected start-up of machines.
When using compressed air applications across sectors, it is not only necessary to ensure high productivity, efficiency and process reliability, but also to always keep the protection of employees in mind. For this purpose, engineers resort to safety valves that ensure safe venting of the system. With the VP546/746 series, automation specialist SMC now offers a modular 3/2-way solenoid valve that not only provides a high level of safety. In addition, the solution impresses with its compact design, modular construction for combination with SMC's AC-D series service units, an integrated check valve for the pilot air, and is optionally available as a single (single-channel) or redundant (dual-channel) system. In addition, the valve can be optionally equipped with a soft-start function as well as an external silencer. Engineers are thus provided with a comprehensive solution to make their pneumatic applications safe - without compromising efficiency and productivity.
Relieving pressure safely
Although safety functions can be implemented with standard components, the effort and risk of not complying with harmonized standards is out of proportion to the benefits. Machine designers therefore benefit from components that have been designed with this in mind. This also applies to the VP546/746 series safety relief valve from SMC. On the one hand, it enables the partial safety function "Safe De-energization" (SDE) and on the other hand the "Prevention of Unexpected Start-up" (PUS). Overall, it meets all four requirements of Article 2c of the Machinery Directive 2006/42/EC.
The integrated check valve compensates for pilot air pressure drops caused by pressure fluctuations on the input side. The operating pressure range of the internal pilot air is between 0.25 and 0.7 MPa - for the external pilot air it is between 0.05 and 0.7 MPa. Thanks to the diagnosis of the valve spool position by safety limit switches, deviations between the input signal and the position of the valve spool are detected. This not only creates more safety, but also saves costs and reduces effort.
A variety of safety limit switches are available from manufacturers OMRON and Rockwell Automation, allowing for versatile and flexible design. The VP546/746 series safety vent valve in two sizes is also available in two different versions: Firstly, as a single-channel valve for category 2 and a maximum achievable performance level d, and secondly, as a dual-channel valve for the highest category 4 and a maximum achievable performance level e (according to EN ISO 13849). The high B10d value of max. 10 million cycles ensures a long service life - and thus has a positive effect on costs.
Easy installation and additional safety
The VP546/746 series has a modular design, both as a single and as a redundant system, and can be easily combined with SMC's AC-D maintenance unit (filter, regulator, lubricator). Assembly and disassembly are quick, which also reduces the maintenance effort. The modular connection to a combined maintenance unit (FRL) does not require any additional hosing. In addition, the block design also reduces space requirements, ensures a uniform and attractive design, and is dust-tight and protected against moisture (protection class IP65).
If users opt for an additional soft-start function, the operating pressure range of the external pilot air is between 0.25 and 0.7 MPa. The function creates additional safety by ensuring a gentle pressure build-up, thereby protecting downstream machine components from abrupt pressure build-up. On the one hand, this prevents accidents caused by rapid and uncontrolled movements and, on the other, it reduces wear on downstream components. As a further option, a vent connection with external silencer can be fitted, which achieves a low sound pressure level and quiet venting noises. The occupational safety of employees is thus increased even without additional hearing protection.