Imagine a complex forestry machine, a modern workshop press, or a production line that requires controlling five or six different actuators. If you use standard monoblock directional control valves for this, you'll quickly end up with a powerful, heavy "spider" with dozens of connectors, tees, and meters of tangled hoses. Add to that leaks and trying to find a fault in this chaos... A nightmare, right?
That's why industry and advanced machine manufacturers have been using a completely different solution for years: CETOP standard subplate mounted valves.
BRhydraulic experts have taken a closer look at the most popular size on the market, which is CETOP 03 (also known as NG6). Find out why engineers love this system, what its "magic" is all about, and why it's worth investing in for your next project.
1. What exactly is the CETOP 03 (NG6) standard?
Unlike ordinary directional control valves, where hoses are screwed directly into the spool body, subplate mounted valves do not have threaded connection ports on the side. Instead, they have a perfectly flat, ground bottom with holes, around which small seals (O-rings) are located.
CETOP (from Comité Européen des Transmissions Oléohydrauliques et Pneumatiques) is a European standard that dictates the exact spacing of mounting holes and oil channels on the bottom of the valve for manufacturers. The designation 03 (or according to ISO standard: NG6 – Nominal Size 6) means that the internal diameter of the main flow channels is approximately 6 mm.
Valves of this size are ideal for systems with flow rates from 40 to 80 liters per minute and operating pressures reaching up to 315-350 bar.
2. The biggest advantage? Complete independence from the manufacturer!
If a coil burns out or a spool jams in a classic directional control valve, you often have to buy exactly the same model from the same manufacturer, otherwise, the threads or screw hole spacing will not fit. Replacement involves unscrewing all working hoses, which guarantees oil spillage.
In the CETOP system, this problem does not exist. The standardized mounting interface means that valves are 100% interchangeable. If a Rexroth, Vickers, or Parker valve breaks down in the middle of the night, and you have a replacement from any other company in NG6 size on the shelf – you simply unscrew four hex screws on top, remove the broken valve, place the new one, and tighten it. You don't unscrew a single hydraulic hose! The base and piping remain untouched. This is a huge time saver during breakdowns.
3. Stackable design: Building a system like Lego blocks
Another powerful advantage of the CETOP system is the so-called "sandwich" (stackable) mounting. All supplies (P, T) and outputs to actuators (A, B) are located in a steel or aluminum base plate (connection plate). However, you don't have to immediately place the directional control valve on this plate.
You can place sandwich valves between them, creating a functional stack. Want to reduce pressure only on one section? Add a modular pressure reducing valve. Want the actuator to lower slower? Add a flow control valve. Want to protect the actuator from uncontrolled lowering? Add a pilot-operated check valve. On top of this "sandwich," you place the directional control valve.
You screw the whole thing together with long screws, creating a compact, sealed, and hose-free multi-functional block.
4. When is it worth choosing CETOP instead of a regular valve?
NG6 subplate mounted valves are a high-end solution. It is definitely worth using them when:
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You are building a complex machine (e.g., a robotic arm, multi-stage press, CNC machine), where precision, leak-free operation, and compactness are priorities.
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You need many modular functions (check valves, throttles, pressure reducers on individual sections).
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You care about machine uptime – in production facilities, quickly replacing a valve without disconnecting hoses can save thousands of zlotys in downtime.
Summary
The CETOP standard is the language spoken by the best fluid power engineers worldwide. Switching to subplate mounted valves initially requires purchasing appropriate base plates, but it pays off with incredible order in the system, safety, and reliability.
At BRhydraulic, you can complete your entire hydraulic stack. Check out our full offer of NG6 (CETOP 03) subplate mounted directional control valves, and if you need help designing a block for your machine – contact our experts!
