Hydraulic Steering Systems; Assembly - Vetus EHPD12R Instrucciones De Instalación

Hydraulic steering systems

An hydraulic steering system basically consists of one or more
pumps as well as a cylinder.
If the steering system contains only one Electro-Hydraulic
Pump (EHP), then it is not necessary to install a (double) check
valve.
The EHP type 'R' is already equipped with a built-in check valve.
See diagram '1' *.
In the case of an hydraulic steering system with 2 or 3 pumps,
on the other hand, a (double) check valve definitely needs to be
installed - both to be able to automatically switch over from one
steering pump to the other, and to be able to prevent the
unused steering pump from following. For details please see
diagram no. '2' and '3'.
Separate check valves
All Vetus EHP's feature a built-in check valve and it is therefore
not necessary to install a separate check valve, see diagrams
'1', '2' and '3'.
There is no need to install separate check valves between the
steering pumps and the cylinder if the (manual) steering pumps
are already equipped with a (built-in) check valve. For details
please see diagram no. '4'.
Relief valve
The EHP already possesses a relief valve to protect the steering
system from damage in the case of a (temporarily) excessive
rudder moment (exceeding the maximum for which the steering
system was originally designed).
By-pass valve
A by-pass valve is necessary if emergency rudder steering is
desired.
When the by-pass valve is open there is no pressure so that the
oil can flow from one side of the piston to the other and the
hydraulic system no longer blocks the emergency (rudder)
steering.
N.B. A by-pass valve can only be used when the cylinders are
balanced.
If emergency steering is desired install a by-pass valve which is
geared to the size of the cylinder; see diagram '5'.
* Individual circuit diagrams are found in the 'Hydraulic dia-
grams' on pages 38-40.
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2.0205

Assembly

Setup of the electrohydraulic pump
The room in which the EHP is to be set up must be dry and well
ventilated. Make sure that the EHP is positioned as closely as
possible to the cylinder.
In selecting a suitable location, consider the possible noise and
vibration caused by the EHP .
The EHP can be placed on flexible engine mountings.
1 Cylinder connections
2 Connection for the compensating line
3 Maximum oil level
4 Filler neck
The filler neck respectively the connection for the compensating
line * must always be located on top; i. e., at the highest point.
* If the installation consists only of a cylinder with an EHP , the
EHP must be equipped with a filler neck and a breather.
If the installation features one or more steering pumps, all oil
reservoirs must be interconnected via a compensating line.
The highest steering pump must be equipped with a filler
neck with a breather. The other pumps must exhibit a filler
neck without an opening.
Assembly of a double check valve
Install a (double) check valve as closely as possible to the steer-
ing cylinder. Make sure that the pipe sections between the
check valve and the cylinder, which are continuously pressur-
ized, are as short as possible.
Install the (double) check valve on an absolutely level surface.
Before installing the steering pump and the cylinder, consult the
instructions for the manual control unit.
Fittings
Never use teflon tape to seal off the screw connections. Liquid
sealants should be applied with great care. Sealants entering
the hydraulic system may cause malfunction.
Electro-Hydraulic Pumps EHPD and EHPE