液压机械低温启动注意事项

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Instructions on the Use of Hydrostatic
( M0 Q' t; f% u( W8 f+ @Drives at Low Temperatures
! d+ h9 n5 M' `4 `( }3 ^6 x/ KLimit conditions for axial piston units
Minimum storage temperature ___________________ - 50 C
1 w# P0 r: }6 \0 H1 qWarm-up phase at low load ________________ as from -40C
Operation under load _____________________ as from -25C
( v, N( W( @! F& T& kGeneral
• For applications at temperatures lower than -25C, we recommend
" M+ n) P9 ?0 a' j0 q! \+ Pthat the shaft seal be made of perbunan or PTFE1). However, in the
case of perbunan, please note that the maximum operating
6 D5 Y8 |6 m; q9 m+ W$ ktemperature is reduced to 90C
( |, h: E# X8 K. }• Moisture in the environment of the axial piston unit must be
' G9 s( V9 P& I: _6 n7 c3 qprevented, because any moisture on the shaft seal can cause the
: F2 J9 ]- m( C/ b( `- H* Aseal lip to freeze on the shaft while the machine is at standstill.
. @6 g1 y# z" v9 l) L& EThen, on starting, the possibility of seal destruction cannot be
/ o3 [; W+ O! g* x8 d! _6 ^4 feliminated.
$ w; p& |" J1 W  b+ h• Viscosity must be maintained within the limits specified in the
' D# [6 q% W9 I% b& [technical data of the axial piston machine by selecting a suitable
6 s  b& Q5 v, c4 chydraulic medium for the entire operating period, both in winter
8 I7 s/ V" G* s* K8 K. tand in the hotter summer temperatures.
- o& n" k6 V! N3 }5 ]The limiting values for viscosity are as follows:
min = 5 mm2/s
short term at a max. permissible temp. of tmax = 115C/90C.
% l7 \5 n9 g8 u! J1 p; b' ]Please note that the maximum temperature of 115C for the
8 T! x: Q4 b5 u& P( ^" y4 l" v( w) shydraulic medium (90C for perbunan) must never be exceeded,
even in specific locations, e.g. the bearing area.
max = 1600 mm2/s
9 C- a) Z" W4 ]/ Gshort term on cold start (n≤1000 rpm, tmin = -40C).
8 z' N' j, ^& h7 ?9 @• Particular attention must be paid to the starting viscosity.
For pumps in open circuit, there is also an acute danger of cavitation
& z; s/ M$ d* U' S5 _: o3 uwhen starting with highly viscous (“gelled”) media in the intake
/ T& X& }" W' C& ]% ^; ~1 Mline, because this type of pump usually starts with the maximum
swivel angle.
• When installing new components, these components must first be
filled at higher temperatures, so that sufficient lubrication is ensured
; x; q* ]8 A# s. X; G$ f' ]in all zones.
• Measures for filters, cylinders, gears etc. must be agreed with the
manufacturers.
Specifications for electronic systems
6 b# \$ K& B. d• Control units, amplifiers, sensors, transducers and solenoids:
Minimum storage temperature ___________________ - 50C
Installation and full operation _____________ as from -40C
• Devices with displays (unless otherwise specified)
Minimum storage temperature ___________________ - 20C
Installation and full operation _____________ as from -20C
% G8 f* u9 ~  p0 ?: c$ L5 ]In the case of switching- and proportional solenoids, possible
$ b2 @9 T+ G2 e  M- cincreases in hysteresis or increased switching times must be
expected due to increasing viscosity of the hydraulic medium at
' z6 l: U5 z' h: C* |/ ylower temperatures.
RE 90 300-03-B/11.01
( w8 S. [: s8 ^1 w( @Warm-up instructions
• Warm up all components to at least -40C.
" Q, A9 {/ b( n• Start the drive engine.
! x( C# [7 R0 B• Warm-up phase for open hydraulic systems
6 t3 c) A! T, @. k0 O3 L; J- The pump starts up with the diesel engine and must be operated
' I$ L  D, q8 c' _4 x9 Ifor at least 10 minutes at the engine idling speed in order to
# e$ H: A4 W+ Iensure self-lubrication.
* f+ p6 M2 K( t5 L! U- The pump must be in low-pressure circulation mode
(max. 50 bar and max. 50% oil flow).
- Generate a circulating pressure of approx. 50 bar at the pump by
a separate pressure make up valve. This operating condition must
+ r; S) C; c+ d) o( L& @  ^be maintained until the system reaches a temperature of -25C.
0 J4 \( T; n# rThe speed of the diesel engine must not be increased during this
; H6 v& F) \' o0 T. b# @period.
- Then slowly operate all system functions several times at low load
in order to warm up the entire system as uniformly as possible.
! g, u5 c* M4 g6 [7 a  U7 nDuring this period, the tank temperature must be monitored, since
it will drop due to the cold hydraulic medium returning to the
3 N/ k" L$ Y7 r" x$ N& ]tank.
7 J- l+ E0 V' K0 `$ X# Y• Warm-up phase for closed hydraulic systems
( n. q3 ]: o, M3 N6 g+ a% R* n- Set the pumps to neutral position without oil flow.
# o3 u3 @# p2 i7 K/ H6 x$ ]- The pump starts up with the diesel engine and must be operated
for at least 10 minutes at engine idling speed.
/ l+ C- Z( @/ ^6 b6 t) w4 V4 s$ u3 E! D- Then slowly swivel the pump outwards. All system functions must
be operated slowly several times at low load until the entire system
reaches a temperature of -25C.
' k, V9 d; ?3 ?3 U* |• Continuous flushing is necessary in all components in order to
6 g3 [" t7 s0 z2 g% Zprevent temperature shocks. The temperature difference between
4 M% k) D' s4 n, wthe hydraulic medium and individual components must not exceed
20C.
7 R5 e- b5 o- Y  Y- z. C3 M• The hydrostatic motors must be flushed transversely via the flushing
# q! |- ~. w) w1 ?; Q: L: ?9 ~(U) and leakage oil ports (T). During this process, the permissible
  V7 {7 a, g9 ?5 _+ T& z8 Ohousing pressures must be monitored. Flushing should remain active
during operation in order to ensure that motors operated only
occasionally are maintained at operating temperature.
• Our axial piston units can be operated under full load as from a
circuit temperature of -25C in the system.