Abstract: The unit includes a sensor means (20) positioned in the collection chamber to undergo activation when the water level reaches a predetermined maximum value; there is also provided an electrically operated withdrawal device (30) connected to the vehicle electrical system, to withdraw the water separated within the collection chamber through the bleed outlet, or to close the outlet; a microprocessor (40) is also provided, connected to the sensor (20) and to the switch (50) of the vehicle electrical power system, to electrically power the withdrawal device (30) when the sensor (20) is activated and the ignition key is in a first activation position (I).

Abstract: An automatic bleed unit for a fuel filter used particularly in diesel engines includes a filter chamber 5 for accumulating water present in the fuel. Sensors 220, 230 and associated floats 24, 25 are provided for determining the level of water in the chamber. Upon reaching a predetermined level, a microprocessor activates a withdrawal device 7 to drain water from the chamber. The device is only activated when the vehicle engine is at rest and the ignition key is in first switch position that makes the relevant electrical system live. A system that verifies the compatibility between the withdrawal device casing 70 and a base part 20 of the sensing system can also be included.

Abstract: A process for manufacturing a filter medium includes preparing a pH 3-5 aqueous suspension of cellulose fibers in a pulper or beater with a concentration of between 3% and 5%. A pH 2.8-3.8 aqueous suspension of glass fibers is prepared in a pulper or beater with a fiber concentration of between 0.5% and 1.2%. A first pulp consisting exclusively of cellulose fibers is prepared, to which a moisture-resistant resin is added. A second pulp is prepared consisting of cellulose fibers and glass fibers in proportions of between 30% and 70%, to which a moisture-resistant resin is added. Two superposed layers of the pulps are formed by methods used in paper manufacture. The two layers are collected on a layer of material able to absorb water. The two superposed layers of pulp are pressed to a pressure of between 0.1 and 1 kg/cm.sup.2. The resultant sheet is dried to a moisture content of 1%. The dried material is impregnated with a 50 wt % solution of acrylic latex, and dried again.