n1.  The storage capacity of the hydraulic oil tank should be appropriate, as shown in Table 2-1 , the hydraulic oil tank

        The capacity should be more than 3 times the LPM value of the hydraulic pump output .

n2.  There is a partition between the oil suction pipe and the oil return pipe.

n3.  Select the oil inlet of appropriate size, and the oil inlet must be equipped with a hole cover and a filter.

n4. In  order to facilitate cleaning, the hydraulic oil tank is provided with side panels of appropriate size . 

n5. An  oil drain is installed at the bottom.

n6.  Install a hydraulic filter on the suction side of the hydraulic pump, the installation position must be more than 500mm away from the bottom of the tank .

n7. The  air vent must be equipped with an air filter to prevent dirt from falling into it.

n8.  Install a thermometer and oil level gauge, so that the operator can easily monitor the oil temperature and oil level.

n9. If  necessary, a cooler must be installed to cool the oil temperature.

n10. The  fuel tank must have sufficient strength to reduce vibration and deformation.

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[Technical Questions and Answers] Construction and Design of Hydraulic Oil Tanks for Construction Machinery

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n1. It  should have proper lubricity, no adverse effects on metal materials or oil seals, etc. At the same time, it must have the ability to prevent oil leakage of oil seals.

n2. In  order to effectively transmit power, the hydraulic oil should be incompressible, and at the same time, it should maintain good fluidity under low temperature and high pressure.

n3.  The change of hydraulic oil viscosity to temperature is small (VI value is high).

n4.  Long-term use is not prone to physical and chemical changes.

n5. It can  prevent rust or corrosion of machine parts.

n6.  Has good heat dissipation capacity.

n7.  Can quickly separate moisture, air, dust, dirt, etc.

n8.  High ignition point.

n9.  Not toxic.

( 1 )  Viscosity and viscosity coefficient

n1. Viscosity: The viscosity of the hydraulic oil will affect the power transmission and lubrication effect of the hydraulic device. Using the hydraulic oil with improper viscosity will cause the parts to wear quickly, the mechanical efficiency is low, the pressure loss is large, the volumetric efficiency is small, the oil leakage is large Bad consequences, so it is very important to choose the correct viscosity hydraulic oil.

    Viscosity is generally divided into two types: absolute viscosity coefficient and dynamic viscosity coefficient. The unit of absolute viscosity coefficient is poise (Poise )The unit of dynamic viscosity coefficient is  Stokes  . 　

n2.  Viscosity index  (VI) P 377 TOP     

           Is the viscosity index refers to a hydraulic oil temperature changes per unit, they produce changes in the relative viscosity ratio of values . Viscosity index is based on US Gulf crude oil with VI = 0 and Penn wax-based crude oil with VI = 100 . The VI value for general use is preferably above 90, such as when used at low temperatures , the VI value must be increased to between 130 and 225 .