A CONTAINER OR A TANK

Abstract: The invention relates to a rigid container, such as a tank, cistern, or other open or closed vessel, which is intended particularly, but not exclusively, for storing, heating or sustaining the temperature of a fluid, and wherein embodies electrical resistance wires or filaments which can be connected to a current source via electrods. A significant feature of the invention is that a) the container comprises a layer of material which is electrically conductive and has the commercial designation Semicon CT 6011:70; and in that b) the layer of electrically conductive material has applied externally thereon a layer of good-insulating, fire-resistant material having the commercial designation Isofiber Struktur.

Description: A CONTAINER OR A TANK The present invention relates to a rigid container, such as a tank, cistern or other open or closed vessel, which is made of synthetic material and is intended for storing, heating, and sustaining the temperature of a fluid, and which incorporates electrical resistance wires or filaments which can be connected to a source of electric current via elec¬ trodes. Under certain conditions, a container of the aforedescribed kind would be universally useful and able to replace many kinds of metal or synthetic-material containers at present used for varying purposes. Containers made of synthetic materials have not been used widely for fluids which require a constant, temporary or variable supply of heat, inter alia, because of the risk that the material will become electrically conductive; because of the possible risk of fire or explosion caused, inter alia, by static electricity, when the vessel contains inflammable liquids; and because it has not been possible hitherto to solve satisfactorily the problem of electrically insulating the container. One example of known metal containers is found in the diesel-oil tanks of diesel-driven motor vehicles. It is well known that the viscosity of diesle oil changes at low temperatures. Consequently, so-called K-diesel is introduced as an additive for the purpose of maintaining the viscosity of the diesel oil at desired values to the greatest possible extent, so that said oil can be used satisfactorily as fuel for diesel engines. This mixture of diesel oil and K-diesel, however, exhibits at least two drawbacks, namely that the additive is only effective at temperatures down to about -18 C, and that it is extremely difficult to extinguish the flames of a diesel oil and K-diesel mixture should the mixture ignite. This additive also increases the price of the fuel overall, Another drawback resides in corrosion, which can give rise to fuel leakage with subsequent fire risk and environmental contamination. In this case, a container made of synthetic material could fully replace vehicle fuel tanks, not only tanks for diesel oil but also tanks for petrol or other liquid fuels. Containers intended for use in other fields, or even metal tanks and cisterns, could be replaced with containers made of synthetic materials, provided that the technical problems can be solved. The basic concept of the invention is to provide a container of the kind described in the preamble which can be used universally, even for inflammable liquids. The aforesaid object is achieved with a container constructed in accordance with the following claim 1. A container constructed in this way can be used as a container for the windscreen washing liquid of an automotive vehicle, thereby eliminating the need to use special-duty washing liquid agents. The necessary sypply of heat to the container can be effected through the agency, e.g., of the vehicle battery, which serves as the current source. The inventive container can also replace the fuel tank of a diesel-engine vehicle or the storage tanks for diesel or other oils. Because the base material from which the container is made is electrically conductive but will not generate static electricity, the heat required can be supplied by transfoππing down the mains voltage, or from a vehicle battery. In both of the aforegiven examples, the insulating layer comprises a material known as ISOFIBER STRUCTURE, which originated in Norway and is retailed by Svelvik Fiber A/S, Norway, and which constitutes an essential part of the invention, since this layer practically excludes the possibility of heat leaking to the surroundings, thereby ensuring that the smallest amount of current possible is taken from the power source. When the container is used as a vehicle fuel tank, the outer surface of the insulating layer is conveniently coated with a further material, e.g. PVC, capable of forming a first protection means against, for instance, the impact gravel or the like from the road surface. The electrical resistance wires or filaments encapsulated in the base material Semicon CT 6011:70, which is retailed through " Asea Compound, Stockholm, Sweden, are dimensioned commensurately with the size of the container and the estimated energy requirement for heating and temperature-sustaining purposes. It will be understood by those skilled in this art that the problem of controlling the voltage suplly automatically can be solved in many ways not disclosed in this document and not forming part of the present invention. Washing machine drums, tumbler-dryer drums and tanks for water heaters are all examples of containers in which metallic material has hitherto been used but in which a container constructed in accordance with the invention would provide a good substitute. In this case, a three-phase alternating current is generally used, and to eliminate the risk of such machines becoming electrically conductive, the inner surfaces of the base material, i.e. Semicon CT 6011:70, should be coated with an electrically insulating but heat-permeable ® layer r for example TEFLON 5 Other fields include systems for storing, e.g., syrup, which readiXy thickens at low temperatures. Vehicles intended for transporting large volumes of mutually different fluids which require the temperature thereof to be maintained within given limits- can be equipped with containers constructed in accordance LO " with the inventive principles. The layer of insulating material .applied externally on the container material, mainly the material sold under the designation Isofiber Struktur and sold, inter alia, Svelvik L5 Fiber- A/S, Svelvik, Norway, is fireproof and can also be exposed externally to flames without risk to the contents of container, even should these contents be inflammable. The insulating material is, furthermore, a very effectibe insula¬ ting material, thereby enabling heat lossed from the container 20 to be kept at negligible levels, which guarantees that the amount of current consumed for heating and heat-sustaining purposes can be maintained at an optimally low level. The material is also resistant, e.g., to attack by mold. 25. A container which is manufactured in accordance with the invention will need practically no maintenance, with the exception of those faults which possibly occur in the current source. 30 Irrespective of the kind of current suplly sustem used, it will be understood that all monitoring devices can be readily mounted in a small, separate control box. No control devices, monitor¬ ing devices or heating devices are mounted inside the container, thereby enabling the container to be produced in a technically 3.5 simple manner. The single figure of the accompanying drawing is a longitudi¬ nal sectioned view of an exemplifying embodiment of a tank constructed in accordance with the invention, namely a fuel tank for a diesel-driven motor vehicle. When seen from outside, the container, or tank, comprises, for instance, a PVC-layer 10, inwardly of which there is applied an insulating layer 11, designated "Isofiber Struktur", the thickness of which will vary in dependence on the use for which the container is intended. Finally, there is applied on the inner surfaces of the layer 11 a further layer of material 12, designated Semicon CT 6011:70, which is an electrically conductive material and which encapsulates fully protected resistance wires or filaments, thus having properties which are known per se. The container material 12 is connected via electrodes to a current source (not shown) in a manner well known to the skilled person, said current source either being a conventio- nal mains supply, optionally transformed to a lower voltage level, or having the form of at least one conventional 12 volt battery. Although the inventive container is of simple construction, it affords a surprising technical effect within, inter alia, the aforesaid fields. Compared with container types known hitherto, the manufacturing costs are significantly lower. Although the materials utilized in producing the composite container structure are each known per se, it is not believed, or known, that, the concept of combining these 'two materials for the purpose of achieving the aforedescribed unique results have been previously realized.

Claims: CLAIMS 1. A rigid container, such as a tank, cistern, or other open or closed vessel, which is intended particularly, but not- -5 exclusively for storing, heating., and sustaning the temperature of a fluid, and which embodies electrical resistance wires or filaments which can be connected to a current source via electrodes, characterized in that a) the container comprises a layer of material which is 0 electrically conductive and has the commercial designation Semicon CT 6011:70; and in that b) this layer of material has provided externally thereon a layer of well insulating, fire resistant material commer¬ cially designated Isofiber. Struktur. 5 2. A container according to claim 1, characterized in that the outer surface of the insulating material layer has provided thereon a layer, for instance, of PVC-material which forms the outer layer or skin of the container. 0 3. A container according to claim 1, characterized in that the container is intended to store temperature-sensitive fluid, such as oil, petrol, syrup or the like, whose proper¬ ties, are impaired at low or very low temperatures. 5 4. A container according to claim 1, characterized in that a ® thin layer of synthetic material, e.g., Teflon is applied on the inner surfaces of the container. 0

Inventors: NILSSON LEIF, NILSSON, LEIF
Applicants: NILSSON LEIF, NILSSON, LEIF
Application year: 1988
Main classification: H05B3
IPC codes: F24H1, H05B3