Bearing materials in the Marine & Pumps sectors

Historically, systems based first on wood, then on bronze, followed by rubber and finally on polyurethane and epoxy resin have been used. All these materials can be roughly divided into two categories: the hard materials, such as bronze and epoxy resin, and the soft ones, such as rubber and polyurethane.

We have decided to develop and introduce two products on the market based on PU, thus expanding the range of materials available to customers in the soft material category. These are ZEDEX^® Dirty Water & ZEDEX^® Blue Water.

In addition we have introduced ZX-100K^® in the naval sector in order to close the existing gap between hard and soft categories.

It is know that in the mixed friction range, friction and wear are around 100 to 1000 times more intense than those in the hydrodinamic range.

Our development approach aimed to reduce the transition speed as much as possible, as it contributes in an essential way to achieving the objectives of friction and wear. In fact: the lower the transition speed, the lower the frictional heat and the wear amount per unit of time.

This allowed us to develop alternative materials to those common on the market, creating added value for the customer and the environment.

At the moment there are 2 materials, that have been developed specifically for naval & hydraulic engineering:
ZEDEX^® Blue Water
ZEDEX^® Dirty Water

While ZX-100K has discovered, in the second decade of the 2000s, a new youth in the naval sector which until then was very conservative and therefore reluctant to use new materials.

ZEDEX^® Blue Water combined with water supply type “hydrostatic light” opens new horizons!

ZEDEX^® Blue Water is successfully used as water-lubricated-grease-free carrier rudder bearings since 2015.

ZEDEX^® Blue Water has been specifically developed for the naval engineering and consents an ecological solution, given that the bearing with water lubrication runs basically wear-free under the loads used with oil lubrication. The characteristics of ZEDEX® Blue Water allow to use it both in hydrodynamic and also in mixed friction conditions.

At the moment, it can be manufactured approx. up to 2000mm outer diameter and the approx. max casting weight is 80kg. The material has already been approved in all major classification societies by one of our OEM customers.

Key features

• The preferred type for mix friction
• Water contact up to 60°C
• Average load capacity
• Low friction coefficient in environments with few abrasive particles
• Low wear coefficient in environments with few abrasive particles
• Available as cast semi-finished product or as bushings according to the customer’s drawing/our standard
• Reduces maintenance
• Easy to install

ZEDEX^® Dirty Water has been specifically developed for applications combined with the presence of many abrasive particles (> 30%) and hydrodynamic conditions.

ZEDEX^® Dirty Water is our latest development in the soft products sector and thanks to its two materials composition, it allows to have a stable material for the outer shell and a balanced-hardness/E-modulus-ratio-material for the inner bearing.

These characteristics of ZEDEX^® Dirty Water allow to reduce the overall thickness of the bush walls, to create a thicker than normal hydrodynamic film and to use it only in hydrodynamic conditions. To minimize the risk of overheating, we recommend designing ZEDEX^® Dirty Water bushings with “cooling grooves” in the upper half.

At the moment, it can be manufactured approx. up to 2000mm outer diameter and the approx. max casting weight is 80kg.

Key features

• The preferred type for water lubrication
• Water contact up to 60°C
• Low load capacity
• Hydrodynamic film needed
• Very low wear coefficient in environments with many abrasive particles
• Available as cast semi-finished product or as bushings according to the customer’s drawing/our standard with or without axial grooves
• Reduces maintenance
• Easy to install

ZX-100K^® closes the existing gap between hard and soft material categories and combines the advantages of both groups.

ZX-100K^® is successfully used as water-lubricated-grease-free carrier neck & flap rudder bearings, or either as pintle bushings or for winches or other deck equipment.

ZX-100K^® fits very well in the naval engineering sector since its characteristics offer excellent reliability and its composition grants a high load capacity material allowing higher radial and axial surface pressures than standard-feature bronze. Furthermore, the material allows having an extremely resistant bearing with zero maintenance, practically without wear and above all, an ecological solution since no lubrication is necessary.

It is engineered as staves bearing for dimensions greater than 380mm, conceding an easy installation in refits and new ships. The material has already been approved in all major classification societies by one of our OEM customers.

Key features

• The preferred type for dry running
• Water contact up to 80°C
• High load capacity
• Very low friction coefficient in the environment with few abrasive particles
• Very low wear coefficient in the environment with few abrasive particles
• Available as extruded semi-finished product or as bushings according to the customer’s drawing/our standard
• Reduces maintenance
• Easy to install

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