Premium quality hydraulic mineral
oil fluids are recommended, like H-LP oils to DIN 51524, part2.
The viscosity range should be 25 to 50 mm²/s (cSt) at 50º C.
Operating temperatures –10 to +70ºC. For other fluids such as
phosphoric acid esters or for other operating conditions consult
YEOSHE for assistance.
NBR (Nitrile) seals are used
for operation with hydraulic fluids based on mineral oil. For
synthetic fluids, as perhaps phosphoric acid esters,
Fluorocarbon seals are required. Consult YEOSHE for assistance.
For maximum pump and system
component functionability and life, the system should be
protected from contamination by effective filtration.
Fluid cleanliness should be in accordance with ISO
classification ISO 4406. The quality of filter elements should
be in accordance with ISO standards.
Minimum requirement for filtration rate ×(mm):
General hydraulic systems for satisfactory operation:
Class 19/15, to ISO 4406
X=25μm (β25≧75) to ISO 4572
Hydraulic systems with maximized component life and
Class 16/13, to ISO 4406
X=10μm (β10≧75) to ISO 4572
It is recommended to use return
line or pressure filters. YEOSHE Filter Division offers a wide
range of these filters for all common applications and mounting
styles. The use of suction filters should be avoided, especially
with fast response pumps.Bypass filtration is a good choice for
best filter efficiency.
Installation and mounting
Horizontal mounting:Outlet port
side or top. Inlet port side or bottom, drain port always
Vertical mounting: Shaft pointing upwards.
Install pump and suction line
in such a way that the maximum inlet vacuum never exceeds 0.8
bar absolute. The inlet line should be as short and as straight
as possible. A short suction line cut to 45º is recommended when
the pump is mounted inside the reservoir, to improve the inlet
conditions. All connections to be leak-free, as air in the
suction line will cause cavitations, noise, and damage to the
Shaft rotation and alignment
Pump and motor shafts must be
aligned within 0.25mm T. I. R. maximum. A floating coupling must
be used. Bellhousings and couplings can be ordered at
manufacturers listed in this catalogue. Please follow the
coupling manufacturer’s installation instructions. Consult
YEOSHE for assistance on radial load type drives.
Prior to start up, the pump
case must be filled with hydraulic fluid (use case drain port).
Initial start up should be at zero pressure with an open circuit
to enable the pump to prime. Pressure should only be increased
once the pump has been fully primed.
Attention: Check motor rotation direction.
Operating noise of pumps
The normal operating noise of a pump and consequently the
operating noise of the entire hydraulic system is largely
determined by where and how the pump is mounted and how it is
connected to the down stream hydraulic system. Also size, style
and installation of the hydraulic tubing have a major influence
on the overall noise emitted by a hydraulic system.
Noise reduction measures
Flexible elements help to
prevent pump body vibration being transmitted to other
construction elements, where possible amplification may occur.
Such elements can be:
Bell housing with elastic dampening flange with vulcanized
(1) Floating and flexible
(2) Damping rails
(3) or silent blocks for mounting the electric motor or the foot
(4) Flexible tube connections (compensators) or hoses on inlet,
outlet and drain port of the pump.
(5) Exclusive use of gas tight tube fittings for inlet
connections to avoid ingression of air causing cavitations and
The drain line must lead
directly to the reservoir without restriction. The drain line
must not be connected to any other return line. The end of the
drain line must be below the lowest fluid level in the reservoir
and as far away as possible from the pump inlet line. This
ensures that the pump does not empty itself when not in
operation and that hot aireated oil will not be recirculated.
For the same reason, when the pump is mounted inside the
reservoir, the drain line should be arranged in such a way that
a siphon is created. This ensures that the pump is always filled
with fluid. The drain pressure must not exceed 1 bar. Drain line
length should not exceed 2 meters. Minimum diameter should be
selected according to the port size and a straight low pressure
fitting with maximized bore should be used.