ECL low-pitched characteristic of the viscosity change at temperatures from 0 up to 80 centigrade degree is necessary for preservation of ECL lubricating ability in a range of SPS working temperatures. At low temperatures ECL should have sufficient fluidity to ensure a normal work of ECL circulating system. At heats the sufficient viscosity of ECL should be kept, that is necessary for creation of the effective hydro-dynamical wedge in the bearing. The physical and electrochemical properties of some ECL are submitted in tables 1, 2.
As we see from tab. 1. the physical properties various ECL strongly differ. It's appreciable that some are heavier than water, others have density near to density of water. It is possible to view an ECL behaviour in water by the results of special "ecological" experiment. The ability of ECL to sink, to form a film on a surface of water, to be dissolved was estimated. The results of this experiment also are rather various. So, the drop of liquid from the test No.1, was fallen in 200 mm height jar filled by cold fresh water from 100 mm height, has sunk and during movement downwards was dissolved only partially, by appearing basically at the bottom.
That most, but in artificial sea water has given other result. The drop of the test No.1 has came to the top and has spread by a thin film on a surface of water. ECL No.1 was completely dissolved in a plenty of water at a stirring. The washing off ECL No.1 from hands by cold water requires the certain efforts.
The drops from the test ECL No.3 have sunk both in sea and in fresh water, thus were completely dissolved not reaching to the bottom of jar. A stirring was not required.
The tests 4 and 5 are completely dissolved on a surface of water.
The researches results of a corrosion aggression of various ECL are submitted in tab.2. The qualitative analysis of the given data testifies to the following. All considered ECL are electrolytes. In themselves they chemically are neutral in relation to the carbon steel, since have alkaline reaction. However they can be or not to be agressive in relation to the carbon steel depending on them mineralization, and also from presence / absence of the dissolved oxygen. The simple check of the ECL corrosion aggression by a method of immersing of steel samples to a long time has shown, that all of them for 2 years of supervision have not caused corrosion damages.
Results of research of various ECL viscosity, given in tab. 1., are of special interest. These researches were fulfilled with using the express - technique. The time of the efflux of a some volume of ECL, having various temperature, through a capillary of the given size under an action of gravitational forces was fixed. The graphic image of the experiment results shown on a fig.3 is represented as demonstrative.
ECL No.1 has the complicated characteristic. At low temperatures (from 0 up to 20 degrees) liquid is too much viscous, there can be problems of an its circulate through the propeller shaft bearings. At high temperatures its viscosity sharply falls and comes nearer to viscosity of water, that also is undesirable.
ECL No.3 most full corresponds with "ideal SPS", however it is necessary to mean, that the research and development in ECL area only begin also choice of the final decision will ahead more.
The various antifriction materials wear resistance under lubricating by various ECL was not investigated. However it is possible to assert, that babbits in this case will work with the not best result, since they are rather sensitive to lubricating conditions. At the same time all unmetal antifriction materials will work better, since the viscosity of named ECL is higher, than a water viscosity. The task consists in choosing such antifriction material, which would have the minimal wear, would not swell in concrete ECL, would minimally react to change of temperature on a friction surface and would capable to take up rather high loadings. The level of the Russian and foreign achievements in antifriction materials area is such. that the necessary material for needs of "ideal SPS" can be quite found.
The problem of reliability of seal located between propeller and propeller shaft stands a little independently among considered. Nevertheless it is extremely important from the point of view of SPS reliability as a whole. For "Ideal SPS" the absolute reliable motionless seal with radial straining of a rubber gasket can be used. The similar seal has well recommended of itself on many vessels.
Thus idea of the "Ideal SPS" creation is quite real. Practically all requirements to such complex can be fulfilled.
What is necessary for the "Ideal SPS" project realization?. Technically it can be carried out in three steps:
- a development of the "Ideal SPS" typical project;
- a fulfilling of an experimental researches program with using of the large-scale SPS model stand;
- realization of a wide operational check.
The Register is going to fixedly look on works for the "Ideal SPS" creation and to render the essential help to the enterprises and experts. The positive results of researches and development will be used for updating of the Register Rules and will be recommended for an inclusion in the IACS Unified requirements.
