The present disclosure concerns the field of lighter systems, in particular lighters for usage with liquefied gas or a mixture of liquid and gas.
Portable combustion products, such as lighters, are commonly designed having a container to store a flammable material, that will be ignited to produce a flame. The flammable material is generally a liquefied petroleum gas (LPG), that is filled under pressure in the container of the lighter through a filling valve of the lighter. During release of the LPG from the container through a release device, in particular an exit valve arranged in the lighter, the gas expands and is mixed with the direct surrounding air. The mixture of gas with the oxygen contained in the surrounding air is ignited at the exit valve of the lighter to produce a flame.
The object of the present disclosure is to provide a lighter and a container for containing liquefied gas or a mixture of a liquid and gas with improved safety.
The present disclosure relates to a lighter as defined in claims 1 and 12. The dependent claims depict advantageous embodiments of the present disclosure.
According to the present disclosure, a container, especially for a lighter and preferably arranged in the lighter, suitable for containing a liquefied gas or a mixture of a liquid and a gas comprises a compressible member which is arranged in the container or a dividing element dividing the container volume into a first volume containing the liquefied gas or the mixture of liquid and gas and into a second separate volume. The compressible member and the dividing element are impermeable to gases and liquids.
In this document, a lighter can be defined as being a portable combustion product and/or a flame producing assembly. Such products and/or assemblies are generally designed to produce a flame out of the combustion of a flammable material, when ignited by an ignition device, that can be integrated to the lighter. The flammable material can be stored within the portable combustion product and/or flame producing assembly, for example in a container comprised within or at the housing of the lighter. The flammable material used in lighters can be liquefied gas, for example liquefied hydrocarbon of the n-butane, isobutane, propane type or a mixture of these gases commonly named liquefied petroleum gas (LPG). The portable combustion products and/or flame producing assemblies are widely used for igniting a variety of combustible materials and items such as cigarettes, candles, flammable gas (e.g., in gas stoves), fireplaces, and many others. Portable combustion products and/or flame producing assemblies can be commercially available in different forms and sizes.
Liquefied gas or a mixture of a liquid and a gas, in particular LPG, has the property to transform gas at least partially into liquid at certain pressure, which allows the gas to be stored in large quantities in a container, mainly in liquid phase, but also partially in gaseous phase (or gaseous sky), both in thermodynamic equilibrium. In filled condition, a typical pressure within the container at 23° C. is 250 kPa (above the ambient pressure surrounding the container). The liquid fraction of the liquefied gas can expand with temperature increase, this in proportions directly related to the cubic expansion coefficient of the liquefied gas. A risk situation can occur if an increase of the ambient temperature results in an increased pressure within the container (compared to the ambient pressure surrounding the container) associated without sufficient expansion space within the container. An increased pressure results in the risk that the container gets over pressurized and thus, may burst with possible rapid combustion of the gas into a fireball (“boiling liquid expanding vapor explosion”). This risk is particularly problematic in case of lighters having a refillable container. If the user overfills the container with liquefied gas, the volume for the gaseous phase is very small such that an increased temperature results in a higher internal pressure compared to the situation in which the container is initially filled with less liquefied gas. Non-refillable containers may also be subjected to this risk, but the problem is solved by the producer itself by controlling the filling level during factory filling.
With the present disclosure, risk of overfilling of the container with liquefied gas or a mixture of liquid and gas can be avoided or reduced, because part of the container volume is occupied by a compressible member. If the ambient temperature increases after initial filling of the container, the pressure in the container also increases. At the same time, the compressible member is compressed due to the increased pressure, providing an increased volume occupied by the liquefied gas. Accordingly, the pressure within the container is lower at an increased ambient temperature compared to a container having no compressible member. Therefore, the risk that the container may burst is reduced with the present disclosure.
According to further optional aspects of the disclosure, such a lighter may incorporate one or several of the following features:
In addition or alternatively, the volume containing the liquefied gas may be a first volume and the volume delimited by the outer shape of the compressible member may be a second separate volume. Preferably, both the second volume occupied by the compressible member may be gas- and fluid-tight with respect to the first volume.
In addition or alternatively, the total volume of the container constituted by the first and the second volume may be constant at a given ambient pressure (in particular at 1 atm) and a given ambient temperature (in particular at 23° C.).
In addition or alternatively, the second volume may be reduced by expanding the first volume.
In addition or alternatively, the compression state of the compressible member may depend on the amount of the liquefied gas or the mixture of liquid and gas contained in the first volume.
The division of the total container volume in two separate and variable volumes may allow the first volume to increase and the second volume to decrease as a consequence of thermal expansion of the liquefied gas, and vice versa if the liquefied gas is cooled down. In particular, the compressible member may compensate the expansion of the first volume within the container. One advantage of such a compressible member is that it can at least partially absorb the pressure that would have been applied by the liquefied gas on the inner walls of the container.
According to a further optional aspect of the disclosure, the compressible member may be compressed from an uncompressed state in which the pressure in the container is identical to the ambient pressure, to a first compressed state when the container is filled with a pre-set maximum amount of liquefied gas or of the mixture of liquid and gas.
At ambient temperature and ambient pressure, the compressible member may be in a relaxed, uncompressed state. When liquefied gas is filled in the container, the compressible member may be subjected to the vapour pressure of the gas, which may result in a first compression state of the member. The maximum amount of liquefied gas that can be filled in the container may be limited by the compressible member at a certain filling pressure to avoid a possible burst of the lighter due to an increased temperature after the filling of the lighter/container.
At constant temperature, the first and the second volumes may be constant, and the compressible member may only be compressed to an extend according to the pressure exerted by the first volume on the second volume. For this purpose, the compressible member may be dimensioned taking into consideration the characteristics of the filling process, especially the temperature at filling, and of the liquefied gas used. Once the first compressed state of the member is reached, further filling of the first volume may no longer be possible without temperature change.
In addition or alternatively, the first compressed state of the compressible member may be achieved when the container is filled with an amount of liquefied gas or of the mixture of liquid and gas at a pressure of 250 kPa above the ambient pressure.
In addition or alternatively, the compressible member could be further compressed from the first compressed state to at least a second compressed state when the pressure in the container is increased by an expansion of the liquefied gas or the mixture of liquid and gas caused in particular by an increased temperature, in particular 60° or 90° C., compared to the temperature, in particular 23° C., which was present during the initial filling of the container with the pre-set maximum amount of liquefied gas or of the mixture of liquid and gas.
In some usage or storage conditions, the temperature of the lighter may increase, which may result in a partial evaporation of the liquid phase into the gaseous phase, accompanied by a pressure increase within the first volume. Consequently, the second volume may be further compressed.
The lighter of the present disclosure may further incorporate following optional aspects.
In addition or alternatively, the compressible member may occupy at least 10% of the total volume of the container when the pressure in the container is identical to the ambient pressure surrounding the lighter, in particular at least 20%, more particular at least 30%.
In addition or alternatively, the compressible member may occupy not more than 20% of the total volume of the container when the pressure in the container is 250 kPa higher than the ambient pressure surrounding the lighter, in particular not more than 15%, more particular not more than 10%.
In addition or alternatively, the compressible member may occupy not more than 10% of the total volume of the container when the pressure in the container is 1700 kPa higher than the ambient pressure surrounding the lighter, in particular not more than 8%, more particular not more than 5%.
In addition or alternatively, the compressible member may be made of a polymer, in particular polyurethane or butadiene-acrylonitrile copolymer.
In addition or alternatively, the material of the compressible member may be porous and may comprise closed cells.
The features described are not limited to the first aspect of the disclosure but may apply, where applicable, to any other aspect of the disclosure.
According to another aspect of the present disclosure, a dividing element dividing the container volume into a first volume containing the liquefied gas or the mixture of liquid and gas and into a second separate volume, in a gas- and fluid-tight manner, may be used instead of or in addition to a compressible member. If the pressure within the first volume increases (in particular due to an increased ambient temperature), the dividing element may move or change its shape in order to increase the first volume and to decrease the second volume at the same time.
According to further optional aspects of the disclosure, such a lighter may incorporate one or several of the following features.
In addition or alternatively, the dividing element may be a membrane or a flexible element.
In addition or alternatively, the total container volume comprising the first volume and the second volume may be constant at a given ambient pressure and a given ambient temperature.
In addition or alternatively, the second separate volume could be reduced by expanding the first volume.
In addition or alternatively, the compression state of the second separate volume may depend on the amount of the liquefied gas or the mixture of liquid and gas contained in the first volume.
In addition or alternatively, the second separate volume may be compressed from an uncompressed state in which the pressure in the container is identical to the ambient pressure, to a first compressed state when the container is filled with a pre-set maximum amount of liquefied gas or of the mixture of liquid and gas.
In addition or alternatively, the first compressed state of the second separate volume may be achieved when the container is filled with an amount of liquefied gas or of the mixture of liquid and gas at a pressure of 250 kPa above the ambient pressure.
In addition or alternatively, the second separate volume could be further compressed from the first compressed state to at least a second compressed state when the pressure in the container is increased by an expansion of the liquefied gas or the mixture of liquid and gas caused in particular by an increased temperature, in particular 60° or 90° C., compared to the temperature, in particular 23° C., which was present during the initial filling of the container with the pre-set maximum amount of liquefied gas or of the mixture of liquid and gas.
In addition or alternatively, the second separate volume may occupy at least 10% of the total volume of the container when the pressure in the container is identical to the ambient pressure surrounding the lighter, in particular at least 20%, more particular at least 30%.
In addition or alternatively, the second separate volume may occupy not more than 20% of the total volume of the container when the pressure in the container is 250 kPa higher than the ambient pressure surrounding the lighter, in particular not more than 15%, more particular not more than 10%.
In addition or alternatively, the second separate volume may occupy not more than 10% of the total volume of the container when the pressure in the container is 1700 kPa higher than the ambient pressure surrounding the lighter, in particular not more than 8%, more particular not more than 5%.
Although any of the previous embodiments may be used in relation with any standard lighter system, some optional features of a liquefied gas and lighter may be outlined.
In addition or alternatively, the liquefied gas of the mixture of liquid and gas may have a vapour pressure at 23° C. that is equal or greater than 104 kPa.
In addition or alternatively, the total container volume may be in the range of 2 to 200 cm3, in particular in the range of 3 to 100 cm3, more particular in the range of 3 to 20 cm3.
In addition or alternatively, the container could be refilled with liquefied gas or a mixture of liquid and gas.
In addition or alternatively, the lighter may comprise a first valve device for refilling the container.
In addition or alternatively, the lighter further may comprise a second valve device for withdrawing gas from the container.
In addition or alternatively, the lighter further may comprise an igniting device for igniting the gas exiting the container through the second valve.
According to another aspect of the disclosure, the container is suitable for containing a liquefied gas or a mixture of a liquid and a gas, wherein a compressible member is arranged in the container or wherein a dividing element divides the container volume into a first volume containing the liquefied gas or the mixture of liquid and gas and into a second separate volume.
The liquefied gas which may be used for the present disclosure can be for example liquefied hydrocarbon of the n-butane, isobutane, propane type or a mixture of these gases commonly named liquefied petroleum gas (LPG).
Additional details and features of the disclosure are described in reference to the following figures in which
Embodiments of the lighters and containers according to the disclosure will be described in reference to the figures as follows.
In
In
The size and material characteristics of the compressible member may be chosen in a way that, the compressible member occupies not less than 15% (in some other examples not more than 10%) of the total volume of the container 1 at 23° C. (v0/V0=15%) at a certain filling pressure, e.g. at 250 KPa (above the ambient pressure). As consequence, the filling volume of the first volume 2 does not exceed 85% under these conditions. Therefore, the compressible member limits the maximum amount of liquefied gas within the container during filling, wherein the first volume 2 can further expand after filing due to an increased temperature by further compressing the compressible member.
Any increase of temperature in the environment, for example to 60° C. or 90° C., leads to a temperature increase of the liquefied gas in the container 1, resulting in a pressure increase of the gaseous phase of the liquefied gas. In the case where the liquid occupies exactly the entire free volume of the reservoir, the compressible element will compress by a value proportional to the increase in volume of the liquid according to its coefficient of cubic expansion. Therefore, the pressure exerted on the compressible member also increases and can for example reach 1700 kPa above the ambient pressure or more, which leads the second volume 3 of the compressible member to reduce even more (
In the practical case of a lighter with an internal volume Vo=10 cm3 filled with isobutane and where the liquid occupies exactly the entire free volume of the container, the rate of crushing vi/vf would be 7 at 1700 kPa and 90° C.
The compression property of the member permits to balance the pressure increase between the first volume 2 and the second volume 3 at constant total volume of the container 1 instead of having the container 1 itself expand and possibly even burst. For portable products such as torches, lighters or utility lighters, the liquefied gas used can be for example liquefied hydrocarbon of the n-butane, isobutane, propane type or a mixture of these gases commonly named liquefied petroleum gas (LPG).
One risk using LPG is that if the initial liquid level is too high (above 85% of the volume fraction at 23° C.), thermal expansion can cause the gas phase to disappear (the container is then in “full hydraulic state”), and the internal pressure can increase very quickly at the slightest increase in environment temperature. This can cause the container to burst as a result of excessive pressurization of the inner walls of the container. An explosion, also called a “boiling liquid expanding vapor explosion” (BLEVE) could even occur in the worst case. This situation is caused by the complete destruction of the pressurized container containing a liquid, whose temperature is much higher than its boiling point at atmospheric pressure with dramatic consequences following the expansion of the gas sky, the sudden vaporization of the liquid, the possible rapid combustion into a fireball and the dispersion of the container fragments.
In
In
In
This embodiment presents a combination of the previously disclosed first and second embodiments, comprising simultaneously a dividing element 51 and a compressible member 54.
The volume proportions disclosed above also apply for the embodiment of
Any other characteristic disclosed for the previous embodiments may apply to the embodiment of
Although the present disclosure has been described above and is defined in the attached claims, it should be understood that the disclosure may alternatively be defined in accordance with the following embodiments:
Number | Date | Country | Kind |
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20315283.0 | May 2020 | EP | regional |
This application is a National Stage Application of International Application No. PCT/EP2021/063885, filed on May 25, 2021, now published as WO2021239725 and which claims priority from European Application No. 20315283.0, filed on May 29, 2020, the entire contents of which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2021/063885 | 5/25/2021 | WO |