Common Questions

As a market leader in speciality lubricants, maintenance and corrosion protection products, OKS is committed to promoting a better understanding of solutions to address the needs of industry. This section, where our experts provide the answers to your questions, is meant as an interactive forum to help promote this understanding.

If you have any questions mail us at contact@oks-india.com

Speciality Lubricants

Q.   In our hot air circulation fans, we have a problem of the grease melting very frequently. Could you please suggest a suitable grease from your range?
A.   In the bearings of the hot air circulaton fans, you can use our synthetic grease, which has an organic polymer as thickener and synthetic oil. This grease can operate up to 180“C and would help in solving this problem.

Q.   What are the advantages of using synthetic compressor oils?
A.   Synthetic compressor oils have the following advantages:

1. They provide long term lubrication. From our experience, we find that they provide at least 5 to 6 times the life of a mineral oil.
2. They offer energy savings. World over, it is found that synthetic oils save at least 2% energy in compressors.
3. There is less expenditure on spare parts. Also, life of the valves and other parts increase considerably.

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Open Gear Lubricants

Q.   Why is Priming lubricant used in gear drives ?
A.   The purpose of the priming lubricant is to fill the surface asperities with the thick film and provide rather uniform contact surface when the gears are initially rotated. It gives an indication of contact depth, gear misalignment like contact pattern variation over the gear circumference etc.
It also protects against corrosion as the virgin surface has the tendency to react with the atmosphere readily.

Q.   How to determine the quantity of priming lubricant required ?
A.   Priming lubricant consumption can be calculated from the following empirical formula:
Q = Quantity of lube required in kg
X = 2 to 2.5 Range (Safety Factor)
q (min) = (g/sq.cm), Specific qty required (experience value)
b = Tooth width (cm)
m = Module in cm
Zra = No of teeth on gear, Zri = No of teeth on pinion
Y = No of pinions
Q in Kg = 2. X. q (min). b. m. (Zra+Y.Zri)/1000

Q.   How is Priming lubricant to be applied ?
A.   When new gear drive is assembled, both contact and non-contact surfaces should be dabbed with the priming lubricant. By experience the hand application (covered with surgical glove) is the best method. Care is to be exercised that there is no air entrapment with in the grease layer.

Q.   What is Running-in process ?
A.   The definition broadly is "intentionally caused initial wear or surface rectification on machine parts put into service".
When new gear surfaces are meshing, the surface asperities will come into contact and are torn at the micro level. The running-in lubricant has some chemical additives, which react with the surface asperities at the micro level and remove the same thus providing a smoother surface. Running-in process achieves most favourable surface structure.

Q.   Why is Running-in carried out ?
A.   Running-in is a pre-requisite for new gears in meshing and for operated gears in some specific cases like realignment, surface refurbishment, changing of pinion mounted bearings etc.
Further, running-in is required for some specific instances like cement mill bearings replacement and any major job done for shell repair etc.

Q.   How to use Running-in lubricant and what is the quantity of lubricant to be used?
A.   While running-in process in ON, the spray system should be allowed to spray maximum quantity of lubricant with out any settings. This will hasten the running-in process by rapidly removing (Washing-off) the surface asperities.

The quantity required for complete running-in process will depend on several factors like,
1. The initial surface contact (i.e. roughness level of contact surfaces).
2. Profile errors on the tooth surface.
3. The machine should be running continuously. The start and stop will delay the process.

Experience shows that, the minimum quantity required would be 1 barrel for single pinion drive and 2 barrels for double-pinion drive.
Steps:
1. Charge the mill with 50% of ball charge (in case of mills) and continue the operation till 60% of load contact area is achieved.
2. Increase the charge by 25% and continue the operation, till 80-85% of load contact area is achieved.
3. After achieving 85% contact area, drive can be released for 100% loading.
Any compromise with the above procedure will lead to premature surface fatigue, which will in turn lead to surface damage. Experience shows that with a little longer running-in process, the life of the gear drive will be longer and the transmission efficiency will be good.
A properly run-in gear drive with effective lubrication along the tooth flank and with good load carrying contact will have 97% transmission efficiency.

Q.   When should we use a Service lubricant?
A.   Once the running-in process is completed with 90-95% load carrying area, the operation should be switched over to service lubricant.

Q.   What is the quantity of Service lubricant to be used?
A.   1. Initially when change over is made from Running-in to service lubricant, allow the gear drive to run with maximum quantity for 48 hours.
2. Note down the temperature profile across the tooth flank surface during the above period.
3. Reduce the consumption by 1kg and monitor for 48 hours. Monitor the tooth flank temperature.
4. Continue the above step till we reach stable tooth flank temperature beyond which any reduction in quantity would raise the tooth flank temperature and damages the surface structure.

However, the quantity of service lubricant required could be calculated from the following empirical formula, which serves as a guideline for settings:
Q (in gm/hour) = 8000*N*W*f*S/10000
Where Q = quantity required in gm/hour
8000 = Empirical value (By experience)
N = No. of Pinions
F = Grease factor (0.38 for Service lubricant)
S = Safety factor (1.2-2.5 based on gear condition)

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