Particulate Contamination

 

Particulate contamination in fluids can be caused by a number of factors:-

 

External Ingress

  • Open tanks/reservoirs
  • Ports left open when servicing
  • Quick connect couplings
  • Worn seals (Cylinders and motors)

 

Component Wear

 

Poor housekeeping

  • Not filtering new/replacement fluid
  • Poor maintenance procedures
  • Not changing out dirty/clogged traditional filters

 

The levels of particulate contamination in a fluid reduces the ability for a fluid to lubricate thereby greatly adding to the wear

and failure of components.

Contamination is the major contributory factor to unexpected component failure and system inefficiency.

 

Component recommended max acceptable ISO Code 

 

  • Flow Control Valves                        20/18/15
  • Gear Pumps/Motors                       19/17/14
  • Diesel Injectors                                18/16/13
  • High Pressure Pumps/Motors      18/16/13
  • Proportional Hydraulics                 17/15/12
  • Servo Valves                                      16/14/11

 

The traditional method to achieve these cleanliness levels is hot oil flushing of a system, while flushing is essential for new systems,

unfortunately on mature system’s this method only allows for a snapshot cleanliness of the system, as soon as the flushing system

is disconnected contamination is immediately reintroduced.

Flushing also does not overcome or address the normal ingress of contamination to a system.

 

How Particulate Contamination is Classified

When fluid analysis is undertaken, the contamination level  is predominantly classified as a three number ISO code eg, 17/15/12.

There are also alternative contamination classes which have historically been used such as NAS and SAE, the equivalent codes can

be seen on this comparison table.

As such ISO 14/12/09 is equivalent to NAS 3 and SAE 0 and so on

 

ISO/NAS/SAE Comparrison Table
ISO/DIS 4406 NAS 1638 SAE 749
13/11/08 2
14/12/09 3 0
15/13/10 4 1
16/14/11 5 2
17/15/12 6 3
18/16/13 7 4
19/17/14 8 5
20/18/15 9 6
21/19/16 10
22/20/17 11
23/21/18 12

 

Did You Know

If you run a pump  (60 litres per minute) at ISO Code 20/18/15 for 8 hours a day you will pass around 46kg of particulate

through your system in a year, if you reduce the ISO code to 19/17/14 this would reduce to around 23Kg a 50% reduction

 

The ISO Code numbers refer to ranges depicting the number of particles ‘larger than’ 4 micron, 6 micron and 14 micron per 1mL respectively.

Obviously, as 6 micron and 14 micron particles are both larger than 4 micron, those particles are all also present in the first number. The second number

only shows particles larger than 6 micron. The last number only shows particles larger than 14 micron.

 

ISO 4406 Code 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Number of Particles per mL More Than 40,000 30,000 20,000 10,000 5,000 2,500 1,300 640 320 160 80 40 21 10 5 2.5 1.3 0.64 0.32 0.6 0.08 0.04 0.02 0.01 0.005
Up to and Including 80,000 60,000 40,000 20,000 10,000 5,000 2,500 1,300 640 320 160 80 40 20 10 5 2.5 1.3 0.7 0.3 0.2 0.1 0.04 0.02 0.01

 

The above table also provides a clear picture of the percentage reduction in particulates by improving the ISO code by a single code, i.e.

improving from an ISO code of 21 to 20 can reflect up to a 50% reduction in particulate.

Maintaining a clean system provides you with equipment reliability and lower maintenance costs, by the use of the innovative Delta Xero unit

configured to maintain fluid cleanliness is the way forward.

 

Please get in touch with Micron Eagle to assess your requirements