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How Caltex Technical Services returned Hitachi EX2500 excavators back to their working best

How Caltex Technical Services returned Hitachi EX2500 excavators back to their working best

If your business involves heavy industry or mining operations, you’ll understand the significant losses that can occur as a result of equipment failure, especially if your essential machinery is operating under harsh conditions and dealing with heavy loads.

A magnetite mine in the Northern Territory recently engaged Caltex Technical Services to investigate issues affecting their 3 Hitachi EX2500 excavators using Caltex Clarity Synthetic Oil.

With the machines being operated at a high utilisation in ambient temperatures often exceeding 40°C, the excavators were experiencing high levels of varnish formation, causing hydraulic pump and hose failures.

Melissa Quinn and Terry Phillips from the Caltex Technical Services and Mining teams were sent to the site to investigate the cause of the breakdowns.

After a discussion with the client and following a detailed investigation, the Caltex team discovered the problems were due to a combination of issues.

1. The root cause was a combination of the high ambient and operating temperatures and the lack of sufficient resonance time for the fluid to ‘rest’ and the lack of fluid cooling. This also led to varnish forming due to the accelerated breakdown of the fluid.

2. Deposits forming on the hydraulic cooling system decreased its efficiency and accelerated the varnish formation.

3. A reaction between the varnish and high operating temperatures was significantly reducing the life expectancy of the hydraulic hoses.

4. The excavators were frequently operating under heavy loads and with high fluid speed. 

5. The above issues also contributed to electrostatic discharge within the oil, which led to further fluid degradation.
The Caltex solution.

The team conducted laboratory testing to identify the early stages of varnish forming.

A 12 month cycle of the hydraulic cooler exchange on the excavators was then recommended and implemented.

Anti-static filters were installed in the hydraulic fluid return to reduce the electrostatic discharge in the oil.

By-pass filters 3µm /2000 Beta were also installed.

Securing a positive outcome and genuine results.

After the Caltex team analysed the excavators then implemented their recommended changes, a range of genuine operational improvements and benefits were realised.

Hydraulic oil temperatures now operate at 80° - 85°C, a reduction of 15° - 20°C.  

The hose life and oil life has now been extended.

There has also been a reduction in the thermal degradation of the hydraulic oil. This has resulted in there has no further lost production caused by the excavators derating.

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