After some information about taking oil samples from gearbox's that have to be shut down before gaining access.
We have approx 30 gearbox's that currently have no Condition monitoring(ticking timebombs).
Gearbox's hold anywhere from 5 litres to 100 lites.
Viscosity is either 220 or 320 cst.
Reason equipment HAS to be shut down is for safety reasons all gearbox's are behind safety guards, it takes approx 30min to 1hr to isolate and gain access to the equipment.
I realise that the contaminants will start to seperate from the oil once shut down.
But at what time after shutting down is it a waste of time and money to take the sample?
(some people are going to ask how long is a peice of string?)

I wouldnt worry about it. According to Stokes Law, the larger particles will fall down faster than the smaller, and due to the oils high viscosity (and increasing viscosity while oil cools down)I would guess you have several hours (without doing the math) before your 4-10 micron particles will settle.

Yes, No worries. the 'cold' oil will hold the smaller particles in suspension.

Install a remote sampling system.

Why not plan to fit the gearboxes with quick connect couplings (suction and return) piped up to outside the guards the next time they are down. When a periodic sample is required then you hook up a portable pump without a filter or bypass the filter on your filter cart and circulate the oil thru the pump for several minutes before sampling the equipment while it is running. This would give you a much more representive sample of the oil circulating in your gearboxes. If the unit requires the oil to be cleaned up then you already have a point to attach your filter cart.

Check out this website Striker, it may have the answer your looking for.
http://www.schematicapproach.com/products-fluidsampling-pitottubes.shtml

I am the Australian distributor for Schematic Approach and have access to their entire range of sampling ports. We are currently going through a similar situation to the one you described at Santos in central Australia (Reason equipment HAS to be shut down is for safety reasons all gearbox's are behind safety guards, it takes approx 30min to 1hr to isolate and gain access to the equipment.) and have found the sampling ports as a way around it.

More than happy to help if I can.
admin@lubemate.com.au

Striker,

When you say all gearboxes are guarded is it the rotating shaft that is actually guarded and not the gearbox? If this is the case, you can add a oil/filler/breather replacement cap that has an oil sampling port manufactured into the cap. Then you can take the samples on the "fly" safely. If interested just send me an email and I will respond with a product I have had success with.

Jim

Jim;
The whole drive system is guarded. The gearbox is approx 300mm inside the guarding.
Currently there no access to check oil levels on the run.
Safety is paramount here, but they have also gone overboard with the safety in some areas.