System Operation - Holmatro DPU 31 PC Manual De Instrucciones

4.4 Fuel
DANGER
Petrol is extremely combustible and explosive in certain circumstances:
• Only refill in well-ventilated areas.
• Smoking is forbidden.
• Close the fuel tank properly to prevent leaking.
• Remove leaked fuel.
CAUTION
Do not use dirty fuel and make sure no dirt, dust or water enters the fuel tank to prevent
damage to the engine.
• Remove the fuel filler cap (Fig. 2/1).
• Add fuel to the maximum level according to the indicator (Fig. 2/8).
• Install the fuel filler cap on the fuel tank and tighten it firmly.
• Start and stop the pump following the instructions (Refer to section 5.4).
5 Operation
5.1

System operation

5.1.1 General
A system is an assembly of a hydraulic pump, hose(s), and one or more tools.
The hydraulic pump is driven by an internal combustion engine, electric motor, pneumatically or by hand
or foot power. This pump displaces hydraulic oil and is capable of building up pressure. The hose is for
transporting the hydraulic oil between the pump and the tool.
The tool has a hydraulic cylinder containing a piston that can move axially. If the cylinder is pumped full
from the bottom, pressure builds up beneath the piston so that it is pushed to the outside. If the cylinder
is pumped full from the top, the piston is forced back into the cylinder.
The direction of the movement of the cylinder is determined by a control valve, the so-called deadman's
handle. This deadman's handle can be turned to the left or the right, thus determining the direction the
piston moves. In the neutral position no pressure is built up in the cylinder and the oil flows back to the
pump without pressure. If the deadman's handle is released, it returns automatically to the neutral
position and the piston immediately stops moving.
In tools like cutters, spreaders and combi tools the axial movement of the piston starts a mechanism
that makes a cutting or spreading movement.
The hose is the piece of equipment that connects the pump to the tool, thus creating a closed system.
5.1.2 CORE™ couplers
The hydraulic hose of the CORE™ system is a single hose, that combines a high pressure supply hose
inside a low pressure return hose. The female coupler has a unique function: after disconnection it
connects the supply and the return lines internally. This means you can connect and disconnect tools
without interrupting the oil supply to the hose.
DPU 31 PC 916.000.116_004
EN
33