WO2003001105A1

WO2003001105A1 - Cable passage apparatus for pressure tanks

Info

Publication number: WO2003001105A1
Application number: PCT/EP2002/006257
Authority: WO
Inventors: Paride Saleri
Original assignee: OMB Saleri SpA
Current assignee: OMB Saleri SpA
Priority date: 2001-06-20
Filing date: 2002-06-07
Publication date: 2003-01-03
Anticipated expiration: 2003-12-20
Also published as: ITMI20011299A1; ITMI20011299A0

Abstract

A cable passage apparatus for pressure tanks particularly but not critically suited for tanks containing LPG which are installed on motor vehicles, comprising one or more conducting material reeds (20) alternated with an insulating material element (22), fixed to the internal face of an integral wall (12) of said tank in correspondence with a pass-through hole (18) obtained on the ring itself; said reeds and at least one part of the insulating material elements (22) are provided with a pass-through opening (24), (40) communicating with the hole (18) for the passing through of one or more electrical wires (34) outside the tank itself.

Description

Description of the patent application for industrial invention having title: "Cable passage apparatus for pressure tanks"

The present invention refers to a cable passage apparatus for pressure tanks.

More particularly, this invention refers to a cable passage apparatus for tanks containing fuel such as LPG that are generally but not exclusively installed on motor vehicles.

It is known that the installation of electrically powered signal and/or control devices is often required inside these tanks that must be connected through electric wires to external apparatuses.

For example, in case of LPG tanks for road transport, an electrically powered signal and/or control device is constituted by the level indicator.

The fluid pressure inside the tanks is high, in the range of many tens of bars; therefore it is very important to avoid any risk of leaks. The wire outlet area which absolutely needs a pass-through opening of the tank, is obviously a critical aspect from this point of view, therefore it implies the use of security devices causing difficulties in manufacturing and high total costs.

A solution for the manufacturing of a cable passage apparatus in a pressure tank requires the creation of a drilled bolt with a tapered thread that is screwed in the tank flange. Wires pass through the bolt hole for the electric connection of the device placed inside the tank and the hole itself is subsequently sealed with pyroceram. It is therefore a complex solution as a bolt with special features and an insulating material such as the pyroceram being able to maintain a suitable interface or contact with the bolt metal in order to ensure a perfect pressure tightness in all conditions of use characterized by pressure and/or temperature changes must be created. The different expansion of the two materials is an important problem that is generally solved by prestressing the pyroceram material. This prestressing, however, implies a critical tightening which is difficult to obtain, as it must be accurately calibrated also taking into consideration the mechanical properties of the pyroceram. Therefore, the total cost of the cable passage apparatus is high considering that, after the installation, an accurate sealing of the hole with specific materials is required. In order to avoid these problems, sometimes non-electrical devices such as mechanical movement devices operating through magnets are used. Such devices are placed inside and outside the tank with a non-magnetic separation wall. Also this solution shows, however, considerable drawbacks. The mechanical detection is not accurate. Moreover, the magnet placed inside the tank progressively collects the slags resulting from the metallic filing therein contained; therefore, as time goes by, the detection signal fades out until it disappears thus requiring the substitution of the device in order to restore the system functionality. The aim of the present invention is to solve the above- mentioned drawbacks.

More particularly, the aim of the present invention is the manufacturing of a cable passage apparatus for pressure tanks suitable for a quick and easy installation that does not require the sealing of the hole from which wires come out for the electric connection.

A further purpose of the invention is the manufacturing of a cable passage apparatus that can be easily obtained. A further purpose of the invention is to provide users with a cable passage apparatus for pressure tanks being able to ensure a high resistance and reliability level in time which is easily and cheaply manufactured. According to the present invention, this and other purposes resulting from the following description are obtained by a cable passage apparatus for pressure tanks which is particularly suitable for tanks containing LPG installed on motor vehicles comprising one or more reeds made of conducting material alternated with an insulating material element and fastened to the internal face of an integral wall flange of said tank in correspondence of a pass-through hole obtained on the ring itself, said reeds and at least a part of the insulating elements being provided with a pass-through opening communicating with the hole for the passage of one or more electric wires outside the tank.

Building and functional characteristics of the cable passage apparatus for pressure tanks of the present invention will be better understood from the following description, wherein reference is made to the figures of the enclosed drawings which represent a preferred and non-limitative embodiment wherein: Figure 1 is a schematic view of a transversal section of the cable passage apparatus of the present invention applied to a tank;

Figure 2 shows the schematic plan view of one of the components of the cable passage apparatus to which the electric wires are tied-up.

With reference to the above-mentioned figures, the cable passage apparatus for pressure tanks of the present invention is applied to the usual flange 10 that is tied-up to the wall 12 of a tank with bolts 14 and welding and the interposition of a gasket 16. The flange 10 is provided with a pass-through hole 18 preferably obtained in the central position so that the electric wires can pass through from inside to outside as described here below. The cable passage apparatus according to the present invention comprises one or more reeds 20 made of conducting material alternated with insulating strips 22 which are positioned and fastened in correspondence of said hole 18 on the internal face towards the tank of the flange 10.

Each reed 20 is made for example of copper, brass or other conducting material and it is advantageously formed by a disc-shaped element which is shown in detail in figure 2 and it is provided with a central opening 24. Said disc-shaped element, has a limited thickness which is, by way of example, comprised between 0.5 and 3 mm and it peripherally has at least an integral appendix 26, having for instance a quadrangular shape forming the bearing base of an end of the electrical wire 28. To this purpose, the appendix/appendixes 26 are provided with a clamping screw 30 for said end of the wire 28. In the preferred embodiment, appendixes 26 are in the number of three and they are placed at 120° along the disc-shaped element perimeter 12 and develop outward in a parallel way with respect to the opposite upper and lower faces of the same element. In the embodiment given by way of example shown in Figure 2, the central opening 24 has a substantially circular profile and at least an integral prolongation 32 which is directed to the centre that is similar to the mentioned appendixes 26 is obtained in it. Said prolongations 26 are preferably in the number of three and they are placed at 120° all along the perimeter of the opening 24 and they have a substantially quadrangular configuration. The appendixes 26 and the prolongations 32 are preferably obtained by shearing during the manufacturing of the reeds 20 in whole and they are aligned by twos between them on the same reeds 20 made of conducting material.

The extension of prolongations 32 towards the centre of the opening 24 is limited and it is about the half of the opening radius.

Prolongations 32 like appendixes 26 are the support for one end of the electrical wires marked with 34 in Figure 1 and, for this purpose, they are provided with a clamping screw 36 for said end.

Insulating material strips 22 are advantageously constituted by a disc-shaped element having a central pass-through hole 40 with an extension equal or higher than the one of the openings 24 of the reeds 20, as to which they don't have either appendixes 26 or prolongations 32.

A wire 28 which is directed inside the tank is connected to each reed 20 in correspondence of one of the clamping screws 30 which is placed on the relevant appendix 26 and, in correspondence of one of the clamping screws 36 which is placed on the relevant prolongation 32, a wire 34 which is directed outside the tank is connected According to the required number of wires 28 and 34, a higher or lower number of reeds 20 which are overlapped among them and alternated with an insulating material strip 22 is used. Said strips are made, for instance, of rubber, Vulcolan, PTFE or other suitable insulating material.

Figure 1 shows in a schematic way a solution of the cable passage apparatus according to the invention, which is applied to the flange 10 of a pressure tank and it is arranged, by way of non-limitative example, to connect two electric wires 28 to be directed inside the tank and three electric wires 34 to be directed outside the tank. In this embodiment, conducting material reeds 20 are three and the insulating material strips 22 are four. Reeds 20 and strips 22 are placed on the internal face of the flange 10 in correspondence of the pass-through hole 18 which is provided on it; particularly the openings 24 of reeds 20 and holes 40 of strips 22 are aligned with the vertical axis of said hole 18. A first insulating material strip 22 is placed in direct contact with said flange; then the three conducting material reeds 20 follow alternated with a strip 22. At the bottom, the last one is delimited by a further strip 22 which may not have the central hole 40. The set of reeds 20 and strips 22 which is thus formed is closed and consolidated by a bracket 42 provided with two or more holes for as many bolts 44 or the equivalent which are inserted in suitably threaded seats which are obtained on the lower face of the flange 10. Wires 34 starting from clamping screws 36 which must come out from the tank, find a suitable passing seat through the hole 18 of the mentioned flange.

Said hole 18 is subsequently, at least partly, filled in with the insulating material 48 such as rubber, Vulcolan, PTFE so that wires 34 coming out of the tank are kept in a fixed position thus avoiding a possible breaking. The partial filling of the hole 18 does not imply a difficult intervention as the insulating material put inside it does not have the sealing function of the strips 22. The sealing of the cable passage apparatus is obtained from the internal face of the tank and it increases in relation to the pressure increase taking place in the tank. As it can be seen from the above-mentioned description, the advantages of the present invention are clear. The cable passage apparatus for pressure tanks of the present invention ensures optimum fluid-proof features, it can be easily installed and its embodiment does not imply difficulties in manufacturing; moreover, the hole for the pass-through of the exit wires does not require particular sealing interventions thus greatly simplifying the installation.

The invention, as described above and here below claimed, has been therefore proposed by way of non- limitative example and it is understood that possible changes and variations will be clear to a technician skilled in the art according to the above mentioned description. With respect to what described and shown by way of example, conducting material reeds 20 and the insulating material strips 22, for example, can have a different configuration and can be grouped between them in a different number according to the quantity of wires 34 to be directed outside the tank through the hole 18. It is therefore understood that the present invention includes all the changes and variations falling within the spirit and the protective scope of the following claims.

Claims

1. A cable passage apparatus for pressure tanks particularly suited for tanks containing LPG which are installed on motor vehicles, characterized in that it comprises one or more conducting material reeds (20) alternated with an insulating material element (22), fixed to the internal face of an integral wall (12) flange (10) of said tank in correspondence with a pass-through hole (18) obtained on the flange itself; said reeds and at least one part of the insulating material elements (22) being provided with a pass-through opening (24; 40) communicating with the hole (18) for the passing through of one or more electrical wires (34) outside the tank itself.

2. The cable passage apparatus according to claim 1, characterized in that each reed (20) is constituted by a disc-shaped element provided with the pass-through opening (24) placed in a central position and, peripherally, with one or more integral appendixes (26) provided with a clamping screw (30) for the end of an electric wire (28) directed inside the tank.

3. The cable passage apparatus according to claim 1 or 2 characterized in that the central opening (24) of the reeds (20) has a substantially circular profile and, inside it, at least an integral prolongation (32) directed towards the centre with a clamping screw (36) for the end of one of said electric wires (34) is obtained.

4. The cable passage apparatus according to any of the above mentioned claims, characterized in that the insulating material element (22) is constituted by a discshaped element having the form of a strip provided with the pass-through opening (40) in the central position and with a prolongation which is equal or longer than the one of the openings (24) of the reeds (20).

5. The cable passage apparatus according to any of the above mentioned claims, characterized in that the ensemble of reeds (20) and insulating strips (22) alternated with the same reeds is consolidated by a bracket (42) fastened with bolts (44) to the internal face of said flange (10).

6. The cable passage apparatus according to any of the above mentioned claims, characterized in that the flange (10) is tied-up to the tank by bolts (14) and/or welding with the interposition of a gasket (16).

7. The cable passage apparatus according to any of the above mentioned claims, characterized in that the wires (34) connected to the reeds (20) by the clamping screws (30) coining out of the hole (18) of the flange (10) are immersed in the insulating material (48) which fills at least part of the hole itself (18).