Cartridge Valves and 2-Way Logic Element Selection
2-way cartridge valves, often called logic elements, switch large flow rates in a small envelope with low pressure drop. The right area ratio, nominal size and control cover decide switching behaviour and sealing. This guide walks through the key selection criteria step by step.
View hydraulic valvesWhat is a 2-way logic valve and when does it pay off?
A 2-way cartridge valve is essentially a spring-loaded seat poppet in a standardised cavity to ISO 7368. It opens or blocks flow between ports A and B; the control pressure in the cover (port X) keeps the poppet closed. Because the seat seals leak-free and the poppet frees up large cross sections, these valves suit high flow rates where spool valves would create too much pressure drop.
- Large flow rates from around 300 l/min with low pressure drop.
- Leak-free blocking, key for holding functions and presses.
- Fast switching thanks to short poppet travel.
- Flexible as a directional, pressure or check function via the control cover.
Which area ratio do I need?
The area ratio is the ratio of the control area in the cover to the effective seat area at A. A 1:1 ratio makes the valve purely flow-dependent, while 1:1.6 or 1:2 provides a safe closing force even at high pressure on B. For pure blocking and check functions pick a large area ratio, for fast directional valves a smaller one.
How do I size nominal size, cover and flow rate?
The nominal size follows from the maximum flow rate and the allowable flow velocity in the seat. Chosen too small, high pressure drop and heating result; chosen too large, the block becomes costly and slow. The control cover sets the function: with a pilot valve, orifice or shuttle valve the same cartridge valve can act as a directional, pressure or flow control valve.
Pick the nominal size from the maximum flow and pressure-drop curve.
To the valve overviewFrequently asked questions
When is a cartridge valve better than a spool valve?
At high flow rates from around 300 l/min and when leak-free blocking is needed. The seat poppet frees up large cross sections with low pressure drop and seals permanently, while a spool always has a small clearance leakage.
What does the area ratio mean on a logic valve?
It is the ratio of the control area in the cover to the seat area at port A. 1:1 makes the valve purely flow-dependent, 1:2 creates a high closing force and suits blocking and holding functions under load pressure.
Can one cartridge valve cover several functions?
Yes. Through the control cover and pilot stage the same 2-way element can act as a directional, pressure or flow control valve. This saves space, because one control block combines many functions in standardised cavities.
Find the right 2-way logic valve
Our hydraulics specialists help with area ratio, nominal size and control cover for your manifold block.
Standardised selection
Cavities and sizes to ISO 7368.
High flow rates
Nominal size matched to your circuit's flow.
Leak-free blocking
Seat poppet for safe holding and load functions.
Expert advice
Hydraulics specialists support your sizing.