FR2535454A1 - DEVICE INDICATING THE LEVEL OF A DIELECTRIC FLUID IN A RESERVOIR - Google Patents

Abstract

THE DEVICE 1 INCLUDES A FLOAT 14 WITH AN ELECTRICAL CONTACT 15, 16 WHICH MOVES ALONG A TUBULAR SLIDE 11 ON WHICH A RESISTANT WIRE 13 IS WOUND. THE SLIDE IS CONSISTED OF A METAL TUBE 11 COATED WITH A LAYER. HIGH MOLECULAR WEIGHT POLYAMIDE MATERIAL, THE THICKNESS OF WHICH IS APPROXIMATELY EQUAL TO THE DIAMETER OF THE RESISTANT WIRE 13. APPLICATION TO TANKS OF MOTOR VEHICLES.

Description

1

  The present invention relates to an indi-

  dielectric fluid level sensor in a tank, and more particularly, fuel level in a vehicle tank, this device consisting of a float with a sliding contact which operates in a

  junction with a wound-resistant wire in the form of solenol-

  from around the float slide, the latter

  generally consisting of a tube in which the car-

  burant is sucked out of the tank.

  In the indicators of the prior art to which the present invention refers, the tube on which the resistant wire is wound is either of plastic material or metal covered with plastic material.

  device has the following significant defect when it is

  at very low operating temperatures, for example below -10 C, ie under such conditions, the contraction of the plastic material is not

  exactly compensated by the contraction of the resistant thread.

  Therefore, the turns of the wire can slide along

  of the support element "which results in a function

  imprecise sliding contact on the float.

  In addition, when the temperature is restored and therefore the resistant wire returns to its support member, there is no guarantee that the position of the contact

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  sliding on the resistant wire corresponds precisely to the level of the fluid in the tank, because the mutual arrangement of the turns of the wire may no longer correspond to the initial setting, the present invention relates to a device

  indicator of the level of a dielectric fluid in a

  the type already described, but not presenting the

disadvantages mentioned above.

  According to the present invention, an indi-

  the level of a dielectric fluid in a tank

  includes a float with an electrical contact, the

  being displaced by the thrust exerted by the fluid, and a slide for the float, the slide presenting

  a resistant wire wound in the form of a solenoid

  turn of its outer surface along which the

  electrical tact slides during operation and is characterized in that the slide consists of a metal tube coated with at least one layer of thermoplastic polyamide material having a very high molecular weight, whose thickness is substantially identical to the

diameter of the resistant wire.

  The present invention will be well understood in the

  reading of the following description made in connection with

  the accompanying drawings in which: Figure 1 is a sectional elevational view of a level indicator according to the present invention;

  FIG. 2 is a sectional view, on a large scale,

  the, taken along the line II-II of Figure 1.

  In FIG. 1, the reference 1 represents a device

  measuring the level of a dielectric fluid,

  fuel in a tank (not shown).

  felt) more particularly a vehicle tank.

  With regard to this reservoir, the figure actually represents a portion of an upper panel 2 having a through hole 3 through which the device 1

  is inserted into the reservoir, The: general characteristics

  1 are essentially known and this device comprises a flanged lid 4 which rests on

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  the tank panel 2 being separated therefrom by a gasket 5 The lid 4 comprises laminated electric terminals 6, 7, 8 and two pipes 9, 10 whose head 9 acts as an intake pipe for extracting by suction the fuel tank, while the second agat in recirculation pipe The pipe 9 is axially connected to a tube 1 I which, outside

  suction of the fluid to remove it from the reservoir.

  see, also acts in support of a resistant wire 13

  rolled in the form of a solenoid over practically the entire length of the tube 11.

  slide for a tubular float 14 mounted inside the

  with a pair of diametrically opposed sliders, 16 connected by their end to an annular component 17 which, via a conductive wire 18 wound in the form of a

  a cylindrical spring around the tube 11, is connected to the sheet

  The lower end of the tube 11 comprises an annular cap 20 through which a hole 21 and provided with a circular filter 22 between the cap 20 and the float 14, the tube 11 is surrounded by a spring 12 to balance the weight of the float 14 when it rests on the lid 20 Finally, the device

  1 comprises a cylindrical tube 19, preferably made of sheet metal,

  which is force-fitted into the cover 4 to enclose the tube 11 and the float 14,

  According to the present invention, the tube 11 is in

  coated with two layers of insulating material 23, 24 The layer 23 has a few thousandths of a millimeter thick

  and is in direct contact with the outer surface of the

  be 11 The coating material must have some essential properties, for example, it must allow electrical insulation, have good mechanical resistance to high temperatures and be a good basis for

  support for layer 24, all these properties are

  in an epoxy resin paint, on the other hand an upward layer 24 is made of a high molecular weight polyamide coating, such as

  the so-called "R Tlsan" material (registered trademark of "polyamide 11").

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  4, The thickness of the layer 24 is slightly greater than the diameter of the resistant wire 131 for example, if the diameter of the wire is 0.2 mm, the thickness of the layer 24 may, by

  for example, be 0.3 mnm As the material used to

  stagger the layer 24 is a thermoplastic material having a high degree of elasticity, the resistant wire 13, after

  winding is subjected to a pre-established pull of

  re to form splines, as shown in 25 in the

  FIG. 2, in the coating 24 and thus avoid any displacement.

  In addition, the thermoplastic properties of the polyamide layer 24 can also be exploited to fix each end 26 of the wire 13 on this layer. In this case, the end of the wire 13 is fixed by feeding the wire into the wire. electric current so that there is sufficient heating of the end to melt the corresponding surface of the polyamide and thus bind the end 26 to the layer 24, numerous tests have shown that the device

  1 is no longer influenced by sudden changes in temperature

  In fact, the layer 24 is thin enough so that there is adjustment of its expansion on the tube 11 by

  following temperature variations, which is essen-

  Likewise, the turns of the wire 13 can not slide longitudinally.

  which confers greater reliability on the device 1 Cepen-

  This is also due to the special material used to form layer 24, ie polyamide 11, and its elastic (flexibility) and chemical properties (resistance to a wide range of acids and alkalis). and

  all types of hydrocarbons) Finally, the thermal properties

  The plastics of the polyamide 11 also allow easy and fast attachment of the opposing ends 26 of the eye 13 to the layer 24. The present invention is not limited to the embodiments which have to be described.

  is, on the contrary, a source of change and variability

  which will appear to the man of the art For example, one

  Layer 23 can be dispensed with because its main function is

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  is to avoid electrical contact between

  26 of the wire 13 and the metal tube 11,

  Native to the layer 23, the Quche 24 could be made slightly thicker, or a different system could be used to fix the ends 26 of the resistant wire 13, 6.

2535454-

Claims (7)

  1 Device for indicating the level of a dielectric fluid in a tank, this device comprising a float (14) with an electrical contact (15, 16), the float being displaced by the thrust exerted by the fluid   of, and a slide for the float, the slide   carrying a resistant thread (13) wound in the form of   north around its outer surface along which   the electrical contact (15, 16) slides during operation   characterized in that the slide is   formed by a metal tube (11) coated with at least one layer (24) of thermoplastic material of weight polyamide   high molecular weight, the thickness of which is substantially identical   to the diameter of the resistant wire (13).   2 Device according to claim 1, characterized   in that the resistant wire (13) is closely   rolled around the surface of the slideway so as to form grooves (25) on the surface of the layer (24) of polyamide material as a result of the flexibility of this layer (24).   3 Device according to claim 1 or 2, characterized in that the layer of polyamide material (24)   a few tenths of a millimeter thick.   Device according to claim 3, characterized in that   in that the diameter of the resistant wire (13) is included between 0.1 and 0.3 mm.   Device according to any one of the preceding claims, characterized in that the material   made of polyamide resists hydrocarbons -   6 Device according to any one of the   previous indications, characterized in that the material   polyamide is polyamide 4 and 11 "deposited RILSAN).   7 v Device according to any one of the   previous indications, in that the extremities   -cposés (16 of the ziezistant yarn (C 13 are embedded in the neck)   (24) of the thermoplastic material at the opposite ends from the metal tube (11},   8 Device according to any one of the   previous indicationscharacterized in that a fine   che (23) of hooking material is placed between the tu-   metal (11) and the layer (24) of polyamide material   Device according to claim 2, characterized in that the anchoring material is an epoxy resin. Device according to claim 8 or 9,   characterized in that the layer (23) of hooking material   ge is a few thousandths of a millimeter thick.