Hydraulic quick-release couplings (QRC) are critical components of any hydraulic system. They let you connect and disconnect lines quickly — without losing working fluid or letting air into the circuit.
What QRC are and how they work
A coupling consists of a male plug and a female socket, each fitted with a check valve. When connected, the valves open and fluid flows; when disconnected, they close automatically, sealing both halves. This enables fast tool changes on construction, agricultural and industrial equipment.
Main lock types
- ISO A (poppet): the most common standard for agricultural machinery; easy to connect thanks to the conical valve.
- Flat Face (ISO 16028): flat-face couplings that minimise oil spillage and keep dirt out — ideal for construction equipment.
- Threaded: screw-to-connect couplings for high impulse pressure and vibration, used in heavy machinery.
- Multi-connectors: connect several lines at once for quick attachment changes.
Never connect couplings of different standards (for example ISO A with Flat Face) even if the diameters seem to match — it will damage the seals and can rupture the system under pressure.
Coupling type comparison
| Type | Standard | Max pressure (bar) | Main use |
|---|---|---|---|
| Poppet (conical) | ISO 7241-1 A | 250–350 | Agriculture, light industry |
| Flat face | ISO 16028 | 350–500 | Construction, quarry excavators |
| Threaded (reinforced) | DIN 3852 (varies) | 450–700+ | Breakers, heavy presses |
| Multi-connectors | Custom | 250–350 | Loaders, harvesters |
How to choose the right coupling
Consider five parameters: working pressure, flow rate (l/min), fluid type, ambient conditions, and seal material (NBR, Viton, EPDM) for the temperature range. Match the connection standard to your existing equipment first, then confirm the thread and body size.
Where to buy in Ukraine
HYDROTECH supplies ISO A, Flat Face, threaded couplings and multi-connectors across Ukraine, with engineer selection by application. Send your machine type and required pressure and our team will recommend the exact part and analogue.