SMC Designs Latest Valves for Pneumatic Control System Operations

June 23, 2021 by Seth Price

SMC recently released their latest VP546E/VP746E valves with added pneumatic control capabilities.

These new valves have three ports and two positions (3/2) and are designed for pneumatic control systems.


The Pneumatic Valves

Each component has a residual pressure release valve that can provide a “soft startup” for a pneumatic control system instead of blasting it with high-pressure air and all of the associated wear and tear. Valves are actuated electrically and use standard 24 V DC power.


VP546E in a typical installation downstream from a filter regulator. Image courtesy of SMC USA


In terms of pneumatic valves, these valves are either opened or closed (2 position) but have three ports (entrance, exit, and residual pressure relief). A pneumatic schematic shows the soft startup part of the valve as the main valve body plus a throttle to limit the flow. Built into this valve body is also a check valve to prevent backflow, should the inlet side lose pressure.


The Soft Start-up Function

The “soft startup” function is safer and much more gentle on hardware than traditional pneumatic valves. It allows the air pressure to slowly rise rather than quickly jump from “off” to “on.” 


Schematic representation of the VP546E/VP746E valves. Image courtesy of SMC USA


This is safer because the pressure gradually increases, meaning a loose or leaky hose does not flop around or blast dust into the air immediately. With the slower startup, there will be less noise generated, which may add to the safety and comfort of the system. It can also extend the lifetime of hardware downstream by not slamming other pneumatic devices with a high-pressure blast of air at startup but will instead increase pressure. 


The VP546E and VP746E

The primary difference between the two base models, the VP546E and VP746E, is their flow rates. The VP546E can handle 7.5 C (or dm^3/(s*bar), and the VP746E can handle 12.6 C. The VP746E can handle a little more pressure as well;1 MPa (145 psi) compared to 0.7 MPa (102 psi) on the VP546E valves. 

Once the appropriate flow rate has been chosen, the engineer can choose from various options, including which electrical connector is included, whether there is an included safety limiter switch, whether there is a manual override, and several others. Optional silencers can be installed as well.


The pressure increase through a pneumatic control system when using the “soft startup” feature available with these valves. Image used courtesy of SMC USA


These valves can be connected in series with other pneumatic devices, such as Filter Regulator Lubricator (FRL) units. At the very minimum, valves should have a filter upstream to remove any particles, water, or compressor oil from the air stream before it reaches the valve. 

SMC has been specializing in automation equipment for over 50 years. In particular, SMC develops hydraulic, pneumatic, and vacuum control systems used in robotics and manufacturing. SMC is a global organization, with subsidiaries in 53 countries.