IL127466A - Weldable housing for fuel tank - Google Patents

Abstract

A fitting's housing (10) for fixedly attaching to a vehicle's fuel tank (38) made of a fuel-vapor impermeable polymeric material, the fuel tank formed with an opening (40) defining boundaries of a duct communicating between the interior and the exterior of the fuel tank, the housing formed with a circumferential connecting portion (16) exceeding the boundaries of the duct, and an outlet port (24) being in flow communication with a portion (18) of the casing extending into the fuel tank; the fitting's housing characterized in that it comprises a casing formed of a core element made of a fuel-vapor impermeable material and being entirely coated by a layer (14) of heat-weldable material suitable for heat-welding to an external surface of the fuel tank; wherein after heat-welding said circumferential connecting portion to the exterior of the fuel tank, a corresponding circumferential connecting portion of the core element is exposed to engage the external surface of the fuel tank. 1419 כ" ג בסיון התשס" א - June 14, 2001

Description

127466/2 i ιϋ jim ni.iri )ϊΐ>ίίΐ ΟΝΛ» Weldable Fitting for fuel tank Raviv Precision Injection Molding n^ltfia 0>i7»H» a»o7ba ts sitt a>_n The inventor: Moshe Erman ^ ^ :Ν^ C.112485 FITTING HOUSING FOR FUEL TANK FIELD OF THE INVENTION The present invention is in the field of fittings for use in vehicle fuel tanks. More specifically the invention is concerned with an improved fitting housing for attaching to a fuel tank and in particular, the invention is directed to a vapor impermeable connection between the fuel tank and the fitting housing.

BACKGROUND OF THE INVENTION A vehicle's fuel tank is typically fitted with several fittings for different pipes or valves, e.g. a roll- over valve, a fuel shut-off valve, a control valve, etc. Modern fuel tanks are made of fuel-vapor impermeable polymeric materials or are treated to become impermeable to fuel vapor by means such as lamination of suitable layers of material or by fluorination, as known per se.

The term "fitting" as used herein in the specification and claims denotes any type of housing for constructing a connection between the fuel tank and an accessory such as, for example, a valve, a tube fitting, etc.

However, fuel valves and pipes and their fittings are attached to the fuel tank by means of housings which are typically heat welded (by the so-called "hot plate process ") to the fuel tank and are not made of fuel-vapor impermeable materials, giving rise to vaporization of fuel through the housing, which is both environmental and safety hazardous.

Owing to evergrowing environmental control requirements, some new international standards now require that also the connection zone of the fitting housing with the fuel tank should be impermeable to fuel vapor.

U.S. Patent No. 5,404,907 discloses, by one of its embodiments, a weldable vapor vent valve formed separately from the valve's body, the housing being made of a heat weldable material and having one or more weld flanges. The valve is attached to the housing during manufacturing in a process so called "over-molding".

U.S. Patent No. 5,139,043 is directed to a weldable vapor vent valve which in one of its embodiments discloses a valve body made of a first polymeric material and an outer connecting means made of a second polymeric material suitable for heat welding to the fuel tank. According to this embodiment, first the valve body is formed by injection molding and then the connecting means is molded over the valve body by the so called over-molding process.

U.S. Patent No. 5,443,098 discloses a chemical additive which is added during the over-molding process and thus provides improved engagement between the components of the valve housing. Other arrangements provide a plurality of ribs between the valve body and the connecting member for improving the sealing relation therebetween.

It is an object of the present invention to provide a new and improved fitting for fixedly attaching to a fuel tank which ensures fuel-vapor impermeability as well as low cost manufacturing. In particular the invention provides such an improved fuel valve housing.

SUMMARY OF THE INVENTION According to the present invention there is provided a vapor valve housing for fixedly attaching to a vehicle's fuel tank made of a fuel- vapor impermeable, polymeric material, the fuel tank formed with an opening defining boundaries of a passageway communicating between the interior and the exterior of the fuel tank; the fittings housing characterized in that: it comprises a casing formed of a core element made of a fuel-vapor impermeable material and being entirely coated by a layer of heat-weldable material suitable for heat-welding to an external surface of the fuel tank; the casing being formed with a circumferential connecting skirt-like portion exceeding the boundaries of the passage-way, and an outlet port being in flow communication with an internal portion of the fitting extending into the fuel tank; wherein after heat-welding said circumferential connecting skirt-like portion to the exterior of the fuel tank, a skirt-like portion of the core element is exposed to engage the external surface of the fuel tank.

According to one specific and preferred embodiment, the fitting is a housing of a vapor valve wherein the casing further comprises a valve receiving portion extending into the interior of the fuel tank and where said outlet portion is in flow communication with the valve receiving portion.

Typically, the valve receiving portion comprises connecting members for attaching thereto a valve member. Such connecting members may be for example a snap-engagement arrangement, screw threading, etc. Alternatively, the housing of the valve member may constitute an integral portion extending from the valve receiving portion of the casing.

Typically, the thickness of the heat-weldable material, at the region of the connecting portion is in the range of between 0.5 to 4 mm. and the heat weldable material is typically polyethylene. The core element is typically made of a material selected from groups of materials such as polyamides, polyesters and polyacetal.

By one preferred embodiment, the connecting portion is a flange having an annular shape. By another embodiment of the invention, the casing _ 4 - 1227466/2 is formed with a reinforcing flange, coaxially disposed with respect to said circumferential connecting portion and has a bottom edge flush with a bottom edge of the circumferential connecting portion. The reinforcing flange is formed out of the heat-weldable material and may have an insert which is an integral part of the core member, or not.

By another aspect of the present invention there is provided a vapor valve casing, wherein after heat-welding a bottom edge of said circumferential connecting portion to an exterior surface of the fuel tank, the core element is exposed to engage an external surface of the tank.

In accordance with the second aspect of the invention there is provided a vapor valve housing wherein the valve receiving portin extends below into the interior of the fuel tank.

In accordance with either the first or the second of the invention's aspects, the casing is molded in a sandwich-type molding process.

BRIEF DESCRIPTION OF THE DRAWINGS For better understanding, the invention will now be described, in a non limiting manner, with reference to the accompanying drawings, in which: Fig. 1A is a cross-sectional view of a casing of a valve housing in accordance with the present invention, prior to attaching to the fuel tank; Fig. IB is a cross-sectional view of the casing of Fig. 1A after attaching to the fuel tank; Fig. 1C is a cross-sectional view of a valve housing assembly attached to a fuel tank after assessing a valve housing, in accordance with the present invention; Fig. 2 illustrates a cross-sectional view of a second embodiment of a fuel-valve housing in accordance with the present invention; Figs. 3A and 3B are cross-sectional views of still other embodiments of fuel-valve housings in accordance with the present invention; and - 5 - 1227466/2 Figs. 4A to 4C are cross-sectional views of further embodiments of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS In Figures 1A to 1C, three consecutive steps of attaching a valve assembly to a fuel tank are shown. In Fig. 1A, a fitting casing generally designated 10 is formed of a core element 12 made of a fuel- vapor impermeable material such as, for example polyamide, nylon, polyacetyl, etc. Entirely coating the core element 12 there is an enveloping layer 14 made of a heat weldable material, typically polyethylene.

The casing 10 is formed with a circumferential connecting portion 16 and a valve receiving portion 18 defining an outlet opening 20 of a fuel fluid duct 22 terminating at an outlet nozzle 24. In the present example, outlet nozzle 24 is formed of the heat weldable material with no core member. However, by another embodiment, the core element 12 may extend to the very end of the outlet nozzle 24.

Valve receiving portion 18 is fitted with some snap engaging projections 28 inwardly projecting and adapted for snap engagement with a valve housing 34 (see Fig. 1C).

It should be appreciated that any type of valve may be used in conjunction with the casing disclosed. Such valves may be, for example, roll-over valves (ROV), shut-off valves (over filling interdiction valves OFI), control valves, shut-off vales, etc.

The thickness of the enveloping material 14 at the zone of the circumferential connecting portion 16 is designated by d and the thickness is typically about 1 ½ - 2 mm. although this size may change, depending on several parameters and may be also in the range of between about 0.5 to 4 mm. - 6 - 1227466/2 A section of fuel tank 38 is shown, having a valve opening 40 and being made of a heat weldable material, as known in the art. It is noted that the circumferential connecting portion 16 of casing 10 is of greater diameter than of the opening 40.

Connecting the casing 10 to the fuel tank 38 is carried out by heat welding of the connecting portion 16. Upon applying heat, the heat weldable material at the zone of the connecting portion 16 melts and adheres to the external surface of fuel tank 38 whereby it becomes attached thereto, reinforced by welded material designated 42, exposing a bottom surface of core element 14 which in the attached position is in tight surface engagement with the external surface of fuel tank 38.

It will thus be appreciated, as seen in Fig. IB, that the above arrangement provides ftiel-vapor impermeable connection between the casing and the fuel tank.

In Fig. 1C, a valve housing 34 has been connected to the valve receiving portion 18 of casing 10, the valve having an outlet extending opposite opening 20 of fuel fluid duct 22. Such a housing is suitable for accommodating any of a variety of valves, as known in the art.

Turning now to Fig. 2, there is shown a fitting 50 which differs from the embodiment of Figs. 1A to 1C in that the valve receiving portion 52 constitutes an integral housing for a valve (not shown), the components of which are assembled into the portion 52 and retained thereto by a variety of means, as known per se.

In the embodiment of Fig. 3A, the fitting 60 is fitted with a circumferential connecting portion 62 as in the previous embodiments and an additional, reinforcing connecting member 64 of similar construction as of connecting member 62, i.e. formed with a core element 66 and an enveloping coating member 68. - 7 - 1227466/2 The position shown in Fig. 3A illustrates the casing 60 after attaching to a fuel tank 70 by heat welding as explained hereinabove with reference to Figs. 1A to 1C. Other components of the casing are essentially similar to those of the previous embodiment.

Turning now to the embodiment of Fig. 3B, there is shown yet another embodiment of a fitting 80 in which contrary to the embodiment of Fig. 3A, the reinforcing connecting member 84 does not comprise a core element but is entirely made of a heat weldable material. However, as seen in this figure, upon applying heat and welding the casing 80 to tank 86, circumferential welding material 88 and 89 accumulates around the reinforcing connecting member 84 and connecting member 86, respectively, to ensure firm connection to the fuel tank 86, while providing fuel-vapor impermeability at the zone of connecting member 90.

The embodiments illustrated in Figs. 4A-4C illustrate fittings for purposes other than for connecting a valve to a fuel tank. However, it is to be noted that the construction and method of application of the fitting to the fuel tank are similar. It is noted that all the embodiments of Figs. 4 to 4B are made in the same manner as explained above, i.e. a core element of a non-impermeable material and an enveloping layer made of a heat weldable material.

In Fig. 4A there is a fitting 100 suitable for connecting a pipe (not shown) to the fuel tank (not shown). The fitting 100 comprises a flange portion 102 for connecting to the fuel tank as explained in connection with the embodiment of Fig. 1 A, and a pipe connecting portion 104 for connecting to a pipe as known per se.

Fig. 4B is also a pipe connecting fitting 110 and is similar to the embodiment of Fig. 4A and comprises an additional, downwardly extending tubular portion 112 extending into a fuel tank (not shown) for reinforcing the attachment to the fuel tank. - 8 - 1227466/2 Fig. 4C is a pipe connecting fitting 118 suitable for connecting a pipe of a significant larger diameter than those of Figs. 4A and 4B, e.g. a fuel filling pipe. The fitting comprises a top tubular extending portion 120 and a co-axial downwardly extending portion 122 for projecting into a fuel tank (not shown), both extending from a connecting flange portion 124.

While preferred embodiments have been shown and described, it is to be understood that it is not intended thereby to limit the disclosure, but rather it is intended to cover all modifications and arrangements falling within the spirit and scope of the invention, as defined in the appended claims.

Claims (14)

- 9 - 1227466/2 CLAIMS:

1. A fitting's housing for fixedly attaching to a vehicle's fuel tank made of a fuel-vapor impermeable polymeric material, the fuel tank formed with an opening defining boundaries of a duct communicating between the interior and the exterior of the fuel tank, the housing formed with a circumferential connecting portion exceeding the boundaries of the duct, and an outlet port being in flow communication with a portion of the casing extending into the fuel tank; the fitting's housing characterized in that it comprises a casing formed of a core element made of a fuel-vapor impermeable material and being entirely coated by a layer of heat-weldable material suitable for heat-welding to an external surface of the fuel tank; wherein after heat-welding said circumferential connecting portion to the exterior of the fuel tank, a corresponding circumferential connecting portion of the core element is exposed to engage the external surface of the fuel tank.

2. A fitting's housing according to Claim 1, wherein the fitting is a housing of a vapor valve and wherein the said outlet portion is in flow communication with a valve receiving portion integral with the casing.

3. A fitting's housing according to Claim 2, wherein the valve receiving portion comprises connecting members for attaching thereto a valve member.

4. A fitting's housing according to Claim 3, wherein the valve member is connected to the valve receiving portion by a snap-engagement arrangement.

5. A fitting's housing according to Claim 2, wherein a housing of the valve member constitutes an integral portion extending from the valve receiving portion. - 10 - 1227466/2

6. A fitting's housing according to Claim 1, wherein the thickness of the heat-weldable material at the region of the connecting portion is in the range of between 0.5-4 mm.

7. A fitting's housing according to Claim 1, wherein the connecting 5 portion has an annular shape.

8. A fitting's housing according to Claim 1, wherein the casing is formed with a reinforcing flange coaxially disposed with respect to said circumferential connecting portion and having a bottom edge flush with a bottom edge of the circumferential connecting portion, the reinforcing io flange being made of a heat-weldable material.

9. A fitting's housing according to Claim 2, wherein the valve is a roll-over type valve.

10. A fitting's housing according to Claim 2, wherein the valve receiving portion extends bellow into the interior of the fuel tank. 15

11. A fitting's housing for fixedly attaching to a vehicle's fuel tank, the housing comprising; a casing formed of a core element made of a fuel-vapor impermeable material and being entirely coated with a layer of heat-weldable material suitable for heat-welding to an external surface of the fuel tank; 0 a circumferential connecting portion exceeding boundaries of an opening formed in the fuel tank; a valve receiving portion; and an outlet port being in flow communication with the valve receiving portion. 5

12. A fitting's housing according to Claim 11, wherein after heat- welding a bottom edge of said circumferential connecting portion to an exterior surface of the fuel tank, the core element is exposed to engage said external surface. - 11 -

13. A fitting's housing according to Claim 12, wherein the valve 5 receiving portion extends bellow a bottom edge of the connecting portion.

14. A fitting's housing according to Claims 1 or 12, wherein the casing is molded in a sandwich-type molding process. 1 12485-8-SPC- (00004)-DD/be- 18/02/01