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Six hydraulic lines on the attachment – do you really have to couple each one separately?
As long as the attachment stays on the machine, six individual hydraulic lines are no great issue. It becomes interesting the moment the attachment has to be changed on a regular basis.
Disconnect six lines. Pick up the next attachment. Assign the correct ports again. Reconnect six couplings. With every attachment change the same sequence starts over – and each time it carries the possibility of mixing up a line.
This is exactly where a Faster multi-coupler comes in. Several hydraulic connections are combined into one common interface between machine and attachment. Instead of operating every coupling individually, the intended hydraulic lines are connected together – in a fixed assignment, with the hydraulic circuits remaining separate.
Six couplings become one coupling operation
The principle is simple at first. The multi-coupler consists of a fixed half on the machine and a loose half on the attachment. Inside them sit several individual coupling elements, each in its own fixed position.
When both halves are joined, the respective couplings meet exactly where they belong. At the next attachment change there is no need to work out which hose goes to which port. The assignment is part of the design, no longer part of the work.
With four, six or more hydraulic lines in particular, what starts as a convenience turns into a clearly defined interface between machine and attachment.
The multi-coupler does not connect the hydraulic circuits to one another. Six lines do not become one shared hydraulic circuit. Every line keeps its own function. What is combined is solely the coupling operation.
Six lines do not mean six times the same hydraulics
Suppose an attachment has six hydraulic lines. The obvious thought is to simply pick a multi-coupler with six matching ports.
For a sound selection that is not enough.
One hydraulic circuit may require a high flow rate, while another only supplies a smaller hydraulic function. In addition there may be a drain line. Depending on the application, electrical plug connections can also be integrated into the coupling unit.
That is why every single port is considered according to its actual task: what flow rate passes through it, what operating pressure it has to withstand, and which nominal size and port thread follow from that. Six ports mean six separate design decisions.
Why an undersized port costs performance
Every coupling sits directly in the flow path of the hydraulic oil. The oil has to pass through the cross-sections and valves inside the coupling.
If the nominal size is chosen too small in relation to the required flow rate, the pressure drop across the coupling rises. The hydraulic pump has to overcome this additional resistance. Part of the hydraulic power is lost in the process and converted into heat – the oil gets warmer, the function on the attachment gets slower.
The number of available coupling positions therefore says nothing about whether the multi-coupler is hydraulically sized correctly. What matters is the flow rate actually required through each individual port.
Parked does not automatically mean depressurised
The attachment was uncoupled cleanly. A few hours later it suddenly becomes hard to connect. One possible reason is residual pressure in a disconnected hydraulic line.
If hydraulic oil is trapped in a line and the parked equipment warms up, for example through direct sunlight, pressure can build up. At the next coupling operation this residual pressure has to be taken into account.
Not every Faster multi-coupler is automatically designed for coupling under residual pressure. Whether residual pressure is permissible, and under which conditions, depends on the particular series and version. That is exactly what needs to be clarified before the selection – not afterwards.
Out on the machine, dirt comes into play
On the data sheet a hydraulic coupling is clean. On a construction machine, a tractor or a forestry machine, reality looks different.
Dust, soil and other contamination often sit exactly where the coupling has to take place during an attachment change. Many Faster multi-couplers therefore use flat-face couplings. The flat coupling faces can simply be wiped clean before connecting.
That matters for a hydraulic system. Dirt removed before coupling does not enter the system, and therefore does not reach valves, pump and filters. At the same time, flat-face couplings keep oil spillage during connection and disconnection to a minimum.
Technically correct and still not a fit on the machine
Flow rate fits. Operating pressure fits. Port threads fit. The number of hydraulic lines is right as well.
And yet the multi-coupler can be impractical on the machine, or impossible to use at all.
In the end the coupling also has to fit mechanically into the existing installation situation. Where does the fixed half sit? How are the hydraulic hoses routed? Is there enough space for actuation? Can moving components collide with the multi-coupler or the hose lines? Points like these decide whether a solution that works on paper also works on the machine.
Which details do we need for a sound selection?
The selection should not start with a particular Faster series. It makes more sense to look first at the machine, the attachment and the existing hydraulic circuits. These eight details are enough for us to build the design properly:
Only once it is known what the individual hydraulic circuits actually require can the right size, coupling elements and version of the multi-coupler be determined.
Does every machine need a multi-coupler because of this?
No. That is part of a sensible selection too – and we say so to a customer even when the smaller solution is the right one.
If a machine has two hydraulic lines and the attachment is changed only rarely, individual hydraulic couplings can be perfectly sufficient.
The more lines there are, and the more often different attachments are swapped, the more attractive a fixed multi-coupler interface becomes. The benefit does not come from a multi-coupler being technically more elaborate. The benefit comes when the solution matches the actual application.
At first glance, a Faster multi-coupler answers a simple question: how can several hydraulic lines be connected at the same time?
In practice there is more to it. Between machine and attachment, a clean, repeatable and hydraulically suitable interface has to be created.
For that, flow rate, operating pressure, nominal size, port thread, residual pressure and installation situation all have to match. Only then do several individual hydraulic couplings become a properly designed multi-coupler solution. That design work is exactly what we do – including special versions when the machine calls for them.
This is why selecting a multi-coupler does not start at the coupling plate. It starts with the hydraulics of the machine.