Viewpoint: hydraulic pump performance is not only down to certification

Pumps for hydraulic applications are typically highly specialised towards certain applications and environments, a reality that must be noted by the MRO (maintenance, repair, operations) professional.

While a pump may achieve certain certifications – such as those outlined by DNV GL, Lloyds and API – that can guarantee a level of competency, how does this actually translate to specifying a replacement for a particular application?

A primary consideration when assessing certifications is to realise that they simply represent a bare minimum.

The first step to specifying a reliable replacement hydraulic pump is to pick a specialist with pedigree

The certification for a particular industry or environment will denote that a product could be used in a certain application, but will offer no guarantees as to its continued performance in that chosen environment.

The first step to specifying a reliable replacement hydraulic pump is to pick a specialist with pedigree.

Hydraulic pumps are utilised in a wide range of industries from subsea to mobile vehicles, so selecting a manufacturer that has a proven track record in multiple industries is a good start.

Even in the same industry, operational demands vary widely, so defining a suitable product with characteristics suited to the system is paramount to ensuring reliability. This may increase initial purchase costs, but is nothing in comparison to repeated periods of downtime.

Choosing a supplier that combines design, manufacturing and testing facilities in-house ensures increased consistency of production, reduced lead times and a more cost effective approach – which transmits savings to the purchaser.

Testing time

Specifying from a manufacturer who employs rigorous product testing policies can ensure that a selected product will display the utmost reliability.

A fully tested product, tailored to your application, will provide greater durability and performance than a product that is simply certified.

The implementation of new material technologies has enabled the latest designs to offer durability when operating with low lubricity fluids, a situation usually encountered in the offshore or marine sectors.

Utilising equally hardened, specialised alloy surfaces that run opposed to each other, for example from the valve plate to cylinder barrel or the steel shoes to swash block, can increase durability in operation.

Similar technologies include the use of hydro-dynamic bearings in hydraulic pumps, which also serve to enhance durability.

The cylinder barrel runs on a thin film of fluid instead of using rolling contact bearings.

The question to ask as an MRO professional is ‘does this pump display the features to tackle the demands of my specific application?’

This lack of contact between moving parts ensures almost infinite bearing life, while also eliminating a potential source of contamination of the hydraulic fluid.

The simplicity of design approach ensures increased reliability and a reduced number of parts that can possibly fail, which is ideal for a maintenance team.

Innovative design features, such as a pressure lubricated swash block, can offer pumps that are perfectly adapted to very demanding applications.

This design provides constant lubrication to the saddle bearings for high pressure and high-cycling applications.

Specifying an adequate replacement pump is therefore not simply signposted by certifications for suitability in differing industries.

The question to ask as an MRO professional is ‘does this pump display the features to tackle the demands of my specific application?’

The first point of reference should, therefore, always be a trusted manufacturer or expert.

By following this strategy you can minimise not only downtime, but also maintenance and ownership costs, when specifying a replacement hydraulic pump.

• David Atkinson is service centre manager at Oilgear