This innovation can largely reduce the formation of lacquering and therefore increases the running times of pumps by four to 10 times, the company claimed.
Common measures such as the regular cleaning of the pump element are very time-consuming and far from ideal over the long run.
Lacquering is partly attributable to an incompatibility between fuel and lubricating oil – especially due to the low TBN of the engine oil. The TBN value describes the size of the so-called alkaline reserve of a engine oil. With its basic property, this serves to neutralise the fuel’s harmful acids.
Due to the capillary effect – reinforced by the additional stroke movement of the plunger – the lubricating oil rises up on the plunger and mixes with the fuel. This results in lacquering in the barrel, as well as in the grooves. The clearance between plunger and barrel is reduced, which ultimately leads to plunger sticking.
Other influencing factors are -
* The mixture incompatibility of different fuels (eg between HFO and MDO: MDO and MGO).
* Fuel temperatures of over 150 deg C in the pump element.
* Switching too quickly between the fuels.
* Contamination with metal traces.
* The admixture of lubricating oils to HFO.
The common measures by which the operator can reduce the formation of lacquering are often time-consuming or not effective enough. This includes moving the control rack with the engine switched off, the elaborate cleaning of the pump elements and the adherence to the permissible fuel viscosities and temperatures as per the OEM provision.
With the new anti-sticking pump elements, it is possible to significantly reduce the formation of lacquering and therefore sustainably lower the risk of plunger sticking. To achieve this, L’Orange optimised the pump elements in terms of geometry, surface coating and scraper ring.
Lubricating oil and fuel are separated, which eliminates the main cause of the formation of lacquering. The scraper ring serves as protection if lacquering occurs in spite of the separation between lubrication oil and fuel. It effectively scrapes the lacquering off the barrel therefore preventing any increase in the lacquering layer in the barrel.
The new special coating and the microgrooves do not allow the lacquering to even develop on the plunger.
L’Orange claimed that the anti-sticking pump elements have several advantages:
* Less lacquering mean longer service intervals and reduced service costs.
* The hydraulic properties of the new anti-sticking pump elements correspond exactly to those of the previous series pumps.
* The new L’Orange anti-sticking pump elements have already been used successfully in various applications. They are currently available for the following systems: 16/24 IMO II, 21/31 IMO I, 21/31 IMO II and 32/40 CD IMO I, II.