Initial Startup Checks
Check the accuracy of design and installation of hydraulic station:
● Make the distance between inlet and outlet as long as possible.
● The pipe orifice of inlet and outlet should be slope and the section eagle should be greater than or equal to 45°，in order to increase passage section ,slower velocity, recommend velocity in inlet is between 0.5m/s and 1.9m/s. and in outlet is below 6m/s.
● Confirm the oil ports are below the oil level in fuel tank in the worst-case scenario (example: all of hydraulic cylinder pistons are extending to the extreme position),
● Specifications of the air filter should be threes greater than the maximum return flow.
● Set the release valve for exhaust on oil returning pipe; and you can also slightly loosen the joint of pumps outlet to vent until there are no bubbles in the oil spill, then you can tighten the joint to produce the same effect.
Notice: This method is suitable for low pressure and you should make sure the pressure will not rise.
Initial start:
● Check the accuracy of the location of oil ports.
● Pumps should vent well when injecting oil.
● Inching running the pumps for a few seconds, and you should loosen the relief valve on the outlet to reach the minimum pressure.
● Do not drive the pumps in a high speed and pressure before the check is over.
Shaft&Coupling
Coupling&spline hole
● The spline hole of the coupling should be floating and automatically be in center, so as to reducing wear, and the slope deviation of two spline shaft is less than or equal to±0.05/25.4mm(deviation of dial indicator)
● Spline hole must be lubricated by molybdenum disulfide lithium-based grease or other similar grease.
● Coupling demand heat treatment to reach the hardness of 29~45HRC.
● The specification of spline hole should meet the one-level standards in SAE-J498b(1971) ,as the coordination is flat root and lateral teeth.
Flat spline shaft
● T7, T67 and T6 series vane pumps provide a high strength key, hence you must use it when installing or changing the pumps , or you can use a new key whose hardness is 27~34HRC and edge angle is 0.8~1*45° to avoid the circular angle in the key slot when it' necessary to change keys。
The load of shaft
● The construction of requirement of flat spline shaft is the same to the spline shaft's.
This series products is only allowed to bear transmission load, do not apply radial and axial load.
Hydraulic Fluid
Classification Of Hydraulic Fluid
HF-0、HF-2 : anti-wear hydraulic oil
HF-1 : common hydraulic oil
HF-3 : water in oil emulsion
HF-4 : water-glycol hydraulic fluid
HF-5 : synthetic hydraulic fluid
Recommended hydraulic Oil
We recommend anti-wear hydraulic oil for all the highest rated working parameter and performance parameter are based on the test using the anti-wear hydraulic.
Other Hydraulic Oil
When using other hydraulic oil, you should lower the Max. rated operating parameters of pumps. in some situations, you have to raise the min. pressure of the inlet, and you can see related sections for details.
Viscosity
Uppermost Viscosity (cold start mode、low speed and pressure)…………………………………860cSt
Uppermost Viscosity (full speed and high pressure)……………...……………..………………108cSt
Best viscosity（longest working time）…………………………………………………………30cSt
Minimum viscosity （full speed and high pressure，for HF-1、HF-3、HF-4、HF-5）………18cSt
Minimum viscosity（full speed and high pressure，for HF-0、HF-2）…………………………18cSt
Viscosity Index
The lowest index: 90V.L. high index can extent operating temperature range but it can also shorten the life of working liquid.
Operating Temperature
the operating temperature mainly depends on viscosity ,also it's related to seal material, and for standard seals , its range is from -30 ℃ to 90 ℃ 。
Max. Temperature
● HF-0、HF-1、HF-2….………………………………………………..………+100 ℃
● HF-3、HF-4.…………………………………………………………………..+50 ℃
● HF-5……………………………………………………………………………+70 ℃
● Biodegradable hydraulic oil (organic grease and rapeseed oil-based grease)…+100 ℃
Min. liquid temperature (also depends on Max. viscosity)
● HF-0、HF-1、HF-2、 HF-5………………………………………………….-18 ℃
● HF-3、HF-4……………………………………………………………………+10 ℃
● Biodegradable hydraulic oil(organic grease and rapeseed oil-based grease)…..-20 ℃
Operating temperature and Viscosity
Operating temperature depends on the viscosity, variety of working liquid and property of pumps.
Usually ,we used the most suitable viscosity. And when the hydraulic pumps cold start, drive it in conditions of low speed and low pressure to heat up the liquid to a suitable temperature, then operate it under full power.
Cleanliness of working fluid
Solid contamination level of oil is required to be lower than level 8 in NAS1618 (or ISO 18/14) and you can use the filter whose filtrate precision is 25 μm(orβ 100 ≥100)
Solid contamination level should meet the need of Min. suction pressure. Recommended filter screen 100 mesh （149μm），and you'd better enlarge the filter size or remove filter when the system demand cold start or using fire resistant oil.
Water pollution of working fluid
Mineral oil-based grease……………………………………………………...….0.1%
Synthetic hydraulic fluid crank case oil and biodegradable hydraulic fluid….….0.05%
The system demand dehydration when moisture content is too high.
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Yongling Hydraulic