Machinery's Handbook, 31st Edition
FLUID CONDITIONING AND STABILIZATION
2795
Kinematic Viscosities
Saybolt Viscosities
Grade Systems
cSt 40°C
cSt 100°C ISO
SUS 210°F
SUS 100°F
SAE Engine Oil
SAE Gear Oil
AGMA
40
4000 3000 2500 2000 1900 1500 1250 1000
200 150 125 100
40 460 320 220 150 100
8 7 6 5 4 3 2 1
40 30 20 16 10 9 8 7 6 5 4
100 150 200 250 300 350 400 500 600
140
50 40 30
90
90 80 70 60 55 50 45 40
800 600 500 400 300 250 200 150 100
85W
10 15 20 30 40 50 60 80
68 46 32 22 15 10
80W
20
75W
10W 5W
90 70 55
Viscosities can be related horizontally
Fig. 7. Hydraulic Fluid Viscosity Chart The viscosity/temperature relationships are based on 95 VI oils and are usable only for mono grade engine oils, gear oils and other 95 VI oils. Crankcase oils and gear oils are based on 100°C viscosity. The “W” grades are classified mono grade engine oils, gear oils and other 95 VI oils. ISO oils and AGMA grades are based on 40°C viscosity.
of sensitive components, and accumulators are used to stabilize the fluid pressure and act as reservoirs. In some cases, cooling must be provided, either passively or actively. Strainers and Filters: Despite being closed systems, hydraulic circuits can become con taminated with particles due to component wear and incoming fluid contaminants. Filters are generally installed after a pump. Installation in the suction line, while more protective, would cause pressure loss in the suction line and jeopardize pump efficiency. An addi tional coarse strainer that creates very little pressure drop is often placed in the suction line to protect the pump. The pressure drop induced by a commercial filter is normally provided by the manufacturer. Hydraulic filters must be capable of handling the pressures and temperatures encoun tered in the system. Chemical compatibility of the filter membrane, body, and seals must also be considered. The filter must be rated for the maximum system flow rate and must be able to handle the viscosity of fluid used in the system. The allowable particle size that can pass through the filter will determine the membrane type. Hydraulic filters are available as in-line, in-tank, and other configurations. Regular maintenance will be required, so filters must be chosen and installed to facilitate membrane replacement.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online