Kobelt 7012 Series, Owner'S Operation, Installation & Maintenance Manual

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Helm pump-7012 Kobelt Manufacturing Co. Ltd.
Rev A MNL-7012 6 of 32
3 A
BOUT
H
ELM
P
UMP
3.1 P
RODUCT
D
ESCRIPTION
Kobelt Manufacturing produces different Helm Pumps, all of which are made from bronze
and stainless steel, except for the thrust and roller bearings and, of course, hardened and
ground pistons. These Helm Pumps can be installed in any location on the vessel because of
their durable materials and watertight construction.
The Helm Pumps incorporate lock valves, filler plugs and interconnecting plugs for multi
station applications. A front mounting plate is available (optional) for all pumps, where the
pump is mounted behind the console face. The following Kobelt Hydraulic Pumps are based
on the same design and are of the VARIABLE DELIVERY TYPE.
The delivery of these pumps is fully adjustable, with easy-to-alter output flow as simple as
turning an external adjusting screw on the pumps’ front face with a standard screwdriver.
Figure 1: Product Overview Diagram
These pumps have been extremely well received by the industry, because of their variable
displacement capability, which allows the operator to select the number of turns from
hardover to hardover, without installing a different pump. For manual hydraulic systems,
under normal conditions, the load on the steering wheel rim should not exceed 36 ft. lbs. (16
kg), and generally the hydraulic system pressure should not exceed 650 psi (45 bar). For
electro-hydraulic systems on emergency-driven hydraulic pumps, the steering angle that must
be maintained manually, in case the power fails, is only 15
ᵒ to either side. At 15 ᵒ the rudder
torque is easily controlled with a helm pump and the helmsman will have no problem
maintaining the steering. One must remember that producing 12 cubic inches per turn at 600
to 1000 PSI requires a tremendous amount of human effort, and it is not practical to expect a
person to produce this kind of pressure and volume continuously.