Patent Application
20060260706
The present invention relates to a flexible hose for conveying fuels.
The invention also relates to the method for making the subject flexible hose.
More specifically, the field of the invention is that of flexible hoses (usually made of rubber) used for conveying fuels such as gasoline, Diesel oils and so on, for example for fueling boats, motor vehicles and for heating applications and the like.
As is known, said prior flexible hoses are conventionally made of a polymeric material, in particular based on nitrilic compounds: however, said prior hoses have a comparatively high permeability to liquid phase vapors from the fuel liquid conveyed in the flexible hose.
Tests performed on samples of a flexible hose of the above mentioned type have shown an average fuel gas permeability corresponding to 300 g/m2/day, as measured by the USA measurement test method SAE J 1527, “Marine Fuel Hoses”
On the other hand, future requirements will require a drastic lowering of the above mentioned value, even to a small limit of 5-15 g/m2/day.
Thus, the main object of the present invention is to provide such a flexible hose which has a very small permeability for the fuel gases evolved by the fuels conveyed thereby.
Another object of the present invention is to provide such a flexible hose for conveying fuels, and a method for making it, which are adapted to meet very severe permeability limits as imposed by recent enforcing rules in this field.
According to one aspect of the present invention, the above mentioned objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a flexible hose and method for making it according to claims 1 and 8, respectively.
Further preferred embodiments of the invention are disclosed in the remaining claims.
With respect to prior flexible hoses for conveying fuels, the inventive flexible hose provides the advantage that it drastically lowers the gas leakages through its wall, thereby meeting very severe limits as enforced by recent law requirements.
The above mentioned and other objects, characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred embodiment of the flexible hose according to the invention, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where:
The flexible hose shown in
Said flexible hose 1 comprises:
The polyamide material forming said layer 3 is preferably nylon 6, nylon 6,6 or nylon 12.
Said layer 3, in particular, is applied by a winding or extruding method on the rubber layer 2, by performing a preliminary adhesive process, or even a thermal process, the function of which is to affix or attach the layer 3 both to the bottom rubber layer 2 and to the top layer 4.
In the modified embodiment shown in
The reinforcement cloth or fabric material layer 5 and 8 could be wound directly onto one another, without an intermediate rubber layer 7.
In the modified embodiment shown in
The metal coil 9, in particular, is in turn embedded in a rubber layer 10, thereon are then applied, in succession, the reinforcement cloth or fabric material 8 and the rubber cover 6.
Alternately, the cloth or fabric material 8 can be also directly arranged under the metal coil 9 and, accordingly, directly contacting the fabric material 5.
The thicknesses of the above mentioned layer can be selected among a lot of suitable thicknesses or gauges, depending on the flexible tube size and design data.
To demonstrate the efficiency of the inventive flexible tube against fuel vapor leakages, in particular through the wall of said flexible hose, the flexible hose or tube 1 of
In this test, three hose lengths of 300 mm each have been coupled to a tank filled by a C-type test liquid.
The sample under test, i.e. the hose and tak, has been weighted with an accuracy of 0.01 g and the original weight has been recovered each 24 h. the permeability degree has been calculated as the weight loss of the sample.
In this test analysis procedure, the greatest permeability level found on the samples in a time period of 15 days at 23° C. was less then 5 g/m2/day (1.58 g/m2/day, as the better result).
The invention, as above disclosed, is susceptible to several modifications and variations, all of which will come within the scope of the accompanying claims.
Thus, for example, the subject flexible hoses could be provided with additional coatings, or with different material covers, with a different order of the layers and, optionally, also with further polyamide additional layers.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2005A 000941 | May 2005 | IT | national |
