Vetus MTC30 Instructions D'installation page 10

Dual Non-return Valve
If a separate dual non-return valve is fitted this must be as close
to the steering cylinder as possible; the pressurised tubing
between the non-return valve and the cylinder remains under
pressure and should be made as short as possible.
Mount the duai non-return valve on an absolutely flat surface.
Connections marked 'P'
are for the steering pump;
connections marked 'C' are
for the cylinder.
Oil Expansion Tank
A part of the hand steering pump serves as an oil expansion
tank. The expansion capacity required depends upon the
amount of oil in the whole steering system and the expected
maximum and minimum ambient temperatures.
If the capacity is insufficient, oil wlil escape out of the breather
hole in the top pump filler cap.
Therefore, install an extra oil expansion tank when:
- the steering system consists of hand two steering pumps
and an electro-hydraulic pump;
- the total length of the tubes system is very large;
- large temperature differences can be expected during oper-
ation;
- if you expect considerable movement during operation, it is
recommended that an extra oil expansion tank be fitted.
Furthermore, an extra oil expansion tank simplifies filling the
system and checking the oil level.
Fit the oil expansion tank above the top steering pump.
Block the breather hole in the top steering pump filler cap.
Connect the oil expansion tank to the topmost steering pump
connector tube using a hose and hose pillar.
N.B. This part of the steering system is virtually pressure-free
(the pressure depends upon the height of the fluid column
between expansion tank and steering pump).
The Vetus oil expansion tank has a breather, when another
make of tank is used, ensure that an air breather is fitted.
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Connections
Never use Teflon tape for sealing the screw connections; liquid
sealants must be used with great care, sealant in the hydraulic
system will create problems.
Steering Pump:
Tube connections to the cylinder are already fitted. When a bal-
ance tube has to be fitted, the connectors (G 1/4) must be
assembled with aluminium or copper sealing washers.
Cylinder:
The tube connections to the steering pumps are already fitted;
a liquid sealant is used. When the connectors are refitted the old
sealant must be removed and new iiquid sealant applied care-
fully.
Non-return Valve:
Assemble the parts in
the non-return valve
using copper or alu-
minium sealing rings.
Hose and Tube Installation
The hydraulic steering components are connected with nylon
tubes (MTC30 only!), nylon hoses or copper or steel tubes for
the other models.
Hydraulic system with double controls, both pumps without
built-in non-return valve:
Connect the tubes from both pumps with the cylinder via the
separate dual non-return valve.
See diagrams 'C1' and 'D1'.
Always keep the connecting tubes as short as possible in order
to restrict the internal resistance.
Hydraulic system with double controls, both pumps with built-
in non-return valves:
Connect the tubes from both pumps with the cylinder via T-
pieces.
See diagrams 'C2' and 'D2'.
Always keep the connecting tubes as short as possible since
they are under pressure and this restricts the internal resist-
ance.
It is recommended that the horizontal tubes be fitted at an angle
of about 3 cm per metre / 3/8 in per ft (pump side higher than
cylinder side) to ensure satisfactory bleeding.
Install the tubes or hoses in such a way that the risk of external
damage and corrosion (for metal tubes) or the effects of chem-
icals and high temperature (nylon hose or tube) is reduced to
the minimum.
Hoses or tubes which pass through a partition must be protect-
ed with bulkhead sleeves, or bulkhead connectors.
Bends must be completely free of kinks; a kink in the tubing
restricts the free flow of hydraulic oil.
Hydraulic Steering Systems 30 - 175 kgm