What is NLGI? Grease Consistency | NLGI consistency number | Hindi

Part-4: What is NLGI? Grease Consistency | एनएलजीआई ग्रेड का क्या मतलब है? ग्रीस और तेल
NLGI का पूर्ण रूप या पूरा नाम National Lubricating Grease Institute सबसे अधिक इस्तेमाल किया जा रहा है |
Consistency is a measurement of basic physical properties of grease indicating grease hardness, which can be adjusted by changing thickener content. Grease consistency has been classified by Japanese Industrial Standards (JIS) based on worked penetration measurements.
Lubrication contamination can cause machinery bearings to seize up as the grease thickens and eventually hardens. Lubrication contamination can degrade lubrication pumps and metering systems.
In Favor of Grease:
1. Grease has superior stop-start performance. When a machine is shut down, oil will drain back to sump but grease remains in the component where it is needed, lowering the risk of a dry start.
2. Worn seals and connectors can retain grease better than oil, which lowers the risk of lubricant starvation and leakage. This also reduces the risk of the lubricant staining or damage to the work product (food, newsprint, textile, etc.).
3. Surplus grease packed tightly around seals and connectors serves as a sealant, preventing the ingress of particles and water. Periodic regreasing can purge contaminants out and away from the working surfaces of the component.
4. Grease enables the use of solid additives such as graphite, zinc oxide or molybdenum disulfide. These additives would settle or become filtered if used in many oils.
In Favor of Oil:
5. Unlike grease, oil flows freely, enabling it to conduct and carry away unwanted heat (thermal convection). This keeps base oil viscosity stable and reduces the risk of heat-induced oxidation and additive depletion.
6. Unlike oil, the churning of grease in gears and bearings results in high energy-consumption losses and heat generation. Energy consumed by oil in a similar application may be only a fraction of that of grease.
7. Because oil doesn’t use thickeners there is no risk of incompatible thickeners clashing, causing changes in grease consistency and other problems.
8. Oil lubricants enable certain contaminants such as water and dirt to be briefly suspended and transported to filters, separators and settling zones. Grease suspends these types of contaminants permanently. In fact, some grease products will suspend 100 percent of their weight in water.
9. Oil volume in machine components can be precisely controlled using level gauges and sight glasses. Grease volume is nearly impossible to monitor and control. Over- and under-greasing are common causes of bearing failures.
10.Oil can be changed without dismantling machine hardware. Grease must be repacked periodically, which involves a considerable cost associated with labor, material and downtime.
11. Oil-lubricated machines are easier to sample for laboratory analysis of wear metals, contaminants and fluid properties. A representative sample of an in-service grease is nearly impossible to obtain.
12. Used oils can be safely handled and disposed of with minimal impact to the environment. Most grease-lubricated machines are total-loss systems, meaning there is no environmentally simple way to recover and dispose of degraded or contaminated products.
#NLGI #Greaseconsistency #Lubrication #Oil #Grease #Bearing #Bearinglubrication #bearingfail #fuctionoflubrication #Whylubrication #Bearinglife #cementpdm #effectofcontamination #bearing #OilVsGrease #EffectofContamination

[@NasirHussain-ih9qe]

Valuable information thanks

[@gkgaur44]

Superb technical explanation sir ..... Good video ..

[@srijansingh9834]

Sir please make a video on how to design or selection of dynamic seperator in VRM .