Patent Publication Number: US-2022217963-A1

Title: Removable assembly for a diffusing apparatus

Description:
TECHNICAL FIELD 
     The invention relates to the field of diffusing apparatus intended to diffuse a substance in the vapor state into the surrounding air, the substance being a liquid including at least one substance selected from semiochemical molecules, pheromones, allomones, kairomones, synomones and fragrances of natural or synthetic origin. In particular, the invention relates to a removable assembly that can be used in a diffusing apparatus of this kind. 
     Technological Background 
     [Compounds such as semiochemical molecules, pheromones, allomones, kairomones, synomones and fragrances of natural or synthetic origin may be used in numerous applications. In agrochemical applications semiochemical substances are for example used to drive off or to control populations of marauding animals. 
     US-A-20180000977A1 describes an evaporator apparatus for extending the range and the efficacy of the odors. The apparatus includes a removable container containing an odor. 
     U.S. Pat. No. 2,140,516 describes an electric vapor generator generating water vapor in an instantaneous manner, the vapor being able to contain a medication or a fumigant.] 
     SUMMARY 
     Some aspects of the invention stem from the idea of proposing a removable assembly for a diffusing apparatus, the diffusing apparatus being intended to diffuse a substance in the vapor state into the surrounding air, enabling low energy consumption to assure a long period of autonomy. 
     Some aspects of the invention stem from the idea of proposing a removable assembly for a diffusing apparatus that regulates a distributed substance flow rate through a porous body by simple temperature control. 
     Some aspects of the invention stem from the idea of proposing a removable assembly for a diffusing apparatus particularly adapted to use a substance of high value with a high accuracy and without loss of substance. 
     In the context of a costly substance, the substance comprising a pheromone, for example, taking liquid form at ambient temperature, wastage thereof must be avoided. Thus in this situation it is wished to feed to an evaporation surface of a porous distributor member a quantity of liquid sufficiently small for the flow to occur without formation of droplets. 
     The flow of the liquid through a porous body is governed when cold by Jurin&#39;s law and when hot by Darcy&#39;s law. 
     Darcy&#39;s law states: 
         Q=KA (Δ H )/ L,  
 
     where Q is the volume flow rate, K is the hydraulic conductivity, A is the area of the section under study of the porous body, ΔH is the piezometric height difference upstream and downstream of the porous body sample and L is the length of the porous body sample. The hydraulic conductivity is calculated using the formula: 
     
       
      
       K=kρg/μ,  
      
     
     where k is the inherent permeability of the porous body, ρ is the mass per unit volume of the liquid substance, g is the acceleration due to gravity and μ is the viscosity of the liquid substance. 
     Jurin&#39;s law corresponds to the formula: 
         h =(2γ cos(θ))/( rρg ),
 
     where h is the height of the liquid, γ is the surface tension of the liquid, θ is the angle of contact between the liquid and the wall of the microchannels, ρ is the mass per unit volume of the liquid, r is the radius of the microchannels and g is the gravity constant. 
     “Removable assembly” will designate an assembly including in particular consumable elements, in particular the liquid substance to be diffused, and able to be moved, inserted or withdrawn in one piece from a diffusing apparatus, as opposed to a fixed part of the diffusing apparatus that includes in particular members with a longer service life. 
     A removable assembly of this kind for a diffusing apparatus may be designed in various manners, on the basis of a container for storing the liquid substance and integrating with the latter a greater or lesser number of elements of the diffuser apparatus, in particular elements the function of which is to distribute the liquid substance outside of the storage container and/or elements the function of which is to generate and/or to direct a flow of air intended to evaporate the liquid substance. The choice to integrate an element of the diffusing apparatus in the removable part rather than in the fixed part may be based on a number of considerations. A first consideration is the mechanical integration of the element with the storage container, for example with the objective of limiting the overall size of the apparatus or the production cost. For example, the integration into the removable assembly of certain elements that cooperate to generate or to guide the flow of air may serve that objective. A second consideration is the functional relation between the element and the liquid substance to be distributed, for example with the objective of favoring the compatibility of the diffusing apparatus with a plurality of different substances with no risk of pollution or in other words with no undesirable mixing. For example, the integration into the removable assembly of certain elements that cooperate to convey the liquid substance may serve that objective. 
     In accordance with one embodiment the present invention proposes a removable assembly for a diffusing apparatus, the diffusing apparatus being intended to diffuse a substance in the vapor state into the surrounding air, the removable assembly including a storage container including an orifice and containing a liquid substance. 
     A removable assembly of this kind may be designed to diffuse various substances. 
     In accordance with one embodiment, said liquid substance includes at least one substance selected from semiochemical molecules, pheromones, allomones, kairomones, synomones and fragrances of natural or synthetic origin. 
     In accordance with one embodiment, the substance is a solution containing at least one sexual or other pheromone, an allomone, a synomone or a kairomone intended to provoke a positive or negative response in relation to the target species, the behavioral result of which may be sexual confusion, confusion of another kind, sexual attraction, attraction of another kind, repulsion of any kind, in arthropods, including arachnids, or including hexapods, including in particular insects, including harmful insects. 
     In accordance with one embodiment, the substance is a solution containing at least one pheromone or a sexual pheromone, an allomone, a synonome or a kairomone intended to provoke a positive or negative response in relation to the target species, the behavioral result of which may in particular be soothing, relaxation, pleasure or intimidation in mammal and bird classes. 
     In accordance with one embodiment, the substance includes a solvent chosen from isopropyl myristate, dipropylene glycol, dipropylene glycol monomethyl ether and an isoparaffinic hydrocarbon, for example isoparaffin L or P or N or V. 
     In accordance with one embodiment, the substance is a solution including at least one substance from the group formed by odoriferous agents used on humans or animals, semiochemical substances, cosmetic agents, essential oils, fragrances and phytosanitary and agricultural agents. 
     In accordance with one embodiment, the odoriferous agents usable on animals are chosen from fatty acids or the esterified form of said fatty acids such as methyl oleate, methyl palmitate, dimethyl azelate and dimethyl pimelate. 
     In accordance with one embodiment, the liquid substance has a viscosity greater than 1 cPa·s at 25° C., for example greater than 8 cPa·s at 25° C., and less than 1 cPa·s at 60° C. 
     In accordance with one embodiment, the substance has a boiling point between 30° C. and 400° C. at atmospheric pressure. 
     In accordance with one embodiment, said storage container further contains an internal cellular retention member impregnated with said liquid substance. 
     In accordance with one embodiment the cellular retention member includes a material chosen from felt, for example wool felt, and melamine foam. 
     In accordance with one embodiment, a plurality of cellular retaining members in contact are disposed in the storage container. 
     In accordance with embodiments, the cellular retention members may have different stiffnesses and/or different hardnesses and/or different densities. 
     In accordance with one embodiment, said inner cellular retaining member is accommodated at least in a mouth zone of said storage container adjacent to the orifice, said cellular retaining member being set back from said orifice. 
     In accordance with one embodiment, the cellular retaining member covers the complete section of the mouth zone adjacent to the orifice of the storage container. 
     Thanks to a cellular retaining member of the above kind, the liquid substance can be reliably retained in the container by capillarity without risk of uncontrolled flow provided that the storage container is not connected to the distributor member in the form of a porous body. 
     In accordance with one embodiment, a plurality of internal cellular retention members are disposed in said storage container, a first inner cellular retaining member situated in said mouth zone of said storage container being stiffer than a second inner cellular retaining member disposed at a distance from the mouth zone. 
     In accordance with one embodiment, a means for retaining said inner cellular retaining member is situated in said container and extends from an end of said storage container opposite said orifice to secure said cellular retaining member in order to retain it in place in said mouth zone. 
     In accordance with one embodiment, the means for retaining the inner cellular retaining member includes a rod fixed to the end of said storage container opposite said orifice. For example, a solid rod with a cruciform end, said end being in contact with the cellular retaining member. 
     In accordance with one embodiment, the storage container includes a retaining lip arranged around the orifice and projecting inward. The internal perimeter of the retaining lip therefore has an opening with smaller dimensions than the orifice. Those dimensions make it possible to contain the inner cellular retaining member set back in the storage container. 
     The removable assembly may include one or more elements that cooperate to distribute the liquid substance outside of the storage container. In accordance with one embodiment, said removable assembly includes a distributor member in the form of a porous body having an evaporation surface situated externally of said storage container to evaporate the substance into the surrounding air. In other words, the porous body comprises pores that constitute microchannels opening onto the evaporation surface. 
     “Microchannel” will denote a canalization the cross section of which has an area between 10 −4  and 10 6  μm 2 . In accordance with one embodiment, said pores have a diameter between 0.01 and 10 μm. 
     In accordance with one embodiment the hollow body includes a wood, textile, ceramic or polymer wick. 
     In accordance with one embodiment, the porous body has a cylinder shape. 
     In accordance with one embodiment, the porous body has a porosity in an interior part of the hollow body lower than a porosity in an exterior part of the hollow body surrounding the interior part. This makes it possible to control the flow rate of the flow in the porous body with the low porosity and to increase exchanges with the air with the high surface porosity. 
     A distributor member of this kind may be connected to the orifice of the container in various ways, either directly or indirectly. 
     In accordance with one embodiment, a connection between the storage container and its associated distributor member is provided by means of piping. 
     In accordance with one embodiment suitable for a diffusing apparatus the fixed part of which includes the distributor member, said distributor member includes a hollow needle configured to pierce a film and/or to move a membrane forming a valve of said storage container and to convey the substance contained in the storage container to the evaporation surface, said film or said membrane being situated at the outlet of said orifice and being intended to be perforated. 
     In accordance with one embodiment, the needle is disposed at one of the ends of the porous body. A needle of this kind may also be employed in combination with a “self-healing” perforatable stopper housed in the orifice of the storage container, that is to say a mass of elastic material that elastically closes the perforation produced by the needle so that no flow occurs after the withdrawal of the latter. 
     In accordance with one embodiment, said film is made of elastomer or a metal film. 
     In accordance with one embodiment, said distributor member is positioned at the outlet of said orifice and the porous body is assembled in sealed manner to the container and has an end portion engaged in the orifice so as to come into contact with said cellular retaining member. 
     Thanks to the above features, the distribution of the liquid substance between the container and the evaporation surface may be produced by direct contact of the porous body with the retaining member, that contact generating capillary tension. 
     In accordance with one embodiment, the end portion includes a lug arranged on an upper part of said porous body and extending along a longitudinal axis of the porous body and configured to receive the substance through contact with the cellular retaining member. 
     In accordance with one embodiment, said removable assembly includes at least one heating member enabling heating of said porous body and an electric contact associated with the heating member and intended to make an electric connection with a fixed part of the diffusing apparatus. 
     In accordance with embodiments, the removable assembly or the fixed part includes at least one temperature sensor measuring the temperature of the distributor member and/or the temperature of the flow of air. In accordance with one embodiment the distributor member is equipped with a temperature sensor, for example at the level of a free end. 
     The temperature sensor may for example be an expansion thermometer or a thermistor. 
     In accordance with one embodiment the heating member and the storage container are disposed on respective opposite sides of the distributor member in the removable assembly. 
     In accordance with one embodiment, the heating member is placed directly on a surface of the porous body. 
     In accordance with one embodiment, the porous body includes at least one recess accommodating at least a part of the heating member. 
     In accordance with one embodiment, the heating member is configured to regulate a flow rate of the substance through the distributor member by modifying a viscosity of the substance without reaching the boiling point of the substance. 
     In accordance with one embodiment, a setpoint temperature is defined as a function of the substance. 
     The flow of the liquid substance may be controlled in various ways. The porous distributor member in particular enables implementation of control of the flow of the liquid substance that is based essentially on the temperature of the porous body. 
     To that end, it is wished that at ambient temperature, without heating the porous distributor member, the hydraulic conductivity K be too low for a flow to occur, that is to say that the situation is a so-called “capillary” situation. 
     When hot, on the other hand, it is desirable that the flow be sufficient to produce a spreading of the liquid substance over the exterior surface of the porous body, which forms the evaporation surface, and that the liquid adhere to that surface. The layer of liquid adhering to the surface modifies the piezometric height difference ΔH and therefore leads to cutting the flow rate of the flow because the hydraulic conductivity K has reached a maximum value. In other words the hot flow, that is to say the flow at the temperature imposed by the heating member, is produced only to the degree that the layer of liquid adhering to the surface is concealed by evaporation and no droplets are detached from the surface of the porous body. 
     The more important parameters are therefore the viscosity of the fluid, its surface tension and the temperature of the porous body. 
     In one embodiment, cos θ is positive, that is to say the substance wets the distributor member, which is for example made of ceramic, the mass per unit volume of the liquid is between 0.6 and 1 g/cm 3 , and the radius of the microchannels is between 5 nm and 1 μm. 
     When cold, that is to say at an ambient temperature below a temperature threshold, the area of the evaporatable liquid is therefore very small: it is the sum of the sections of the microchannels opening onto the evaporation surface. It is therefore possible to obtain a state in which the liquid substance is set back in the hollow body with no possibility of flow. In this state the evaporation when cold depends on the volatility of the liquid and may be substantially zero if that volatility is sufficiently low. The temperature threshold depends on the physical properties of the hollow body (porosity, section of the pores), the physical properties of the liquid (viscosity, surface tension), and motive forces liable to generate a flow (gravity, pressure). 
     The reduction of the dynamic viscosity of the substance by the heat furnished by a heating member enables a fluid to circulate in the distributor member in accordance with Darcy&#39;s law and then to spread on the surface of said distributor member. With no input of heat, the flow is fixed because the sum of the adhesions in the distributor member follows Jurin&#39;s law. In other words, flow is allowed through the distributor member when hot, because of the dynamic viscosity reduction induced by the rising temperature, but retained at the surface by the force of adhesion between the fluid and the surface of the distributor member, as a consequence of the wettability of the fluid on the evaporation surface. At room temperature the force of adhesion between the fluid and the surface of the microchannels in the hollow body is such that the liquid remains confined in the distributor member. 
     During flow, more energy is required to form a droplet that will be detached than to maintain the liquid substance in the distributor member and the storage container. This implies two conditions: 
     1. the dynamic viscosity of the substance must be not be too low within the temperature range that can be reached with the aid of the heating member, and
 
2. the liquid leaving the storage container must be in equilibrium with atmospheric pressure, which can be brought about in a number of ways. For example, the part of the storage container with no liquid is depressurized. Alternatively this equilibrium is assured by a pressure management system of the part with no liquid.
 
     In accordance with one embodiment, said substance has a viscosity varying as a function of temperature, said viscosity and the surface tension of the liquid substance being such that the acceleration due to gravity is exerted from the orifice in the direction of the porous body, said substance being unable to flow through said porous body at an ambient temperature less than a first temperature, the first temperature being greater than 0° C., and said substance being able to flow through said hollow body at a second temperature higher than said first temperature. 
     The first temperature may be fixed in various ranges. If the diffusing apparatus is intended to be used outdoors, the first temperature will in particular be chosen as a function of local climate data. In accordance with embodiments, the first temperature is for example between 1° C. and 50° C., or between 5° C. and 40° C., or between 10° C. and 35° C., or between 15° C. and 25° C. 
     The removable assembly may include elements that cooperate to generate and/or to direct a flow of air intended to evaporate the liquid substance. In accordance with one embodiment, said removable assembly includes an air flow guide situated at the periphery of said orifice. 
     In accordance with one embodiment, said air flow guide is intended to guide a flow of air in a direction tangential to the evaporation surface or to the intended location of the evaporation surface and said removable assembly includes sealing elements for producing sealed connections between the container and said flow guide and between the flow guide and said porous body. 
     In accordance with one embodiment, the removable assembly includes a tubular chute extending around the porous body or the location intended for the porous body, said vein enabling the flow of air to be guided over said porous body. 
     In accordance with one embodiment, said storage container has an elongate shape in an axial direction, said orifice being situated at an axial end of the storage container, the evaporation surface of said porous body being parallel to the axial direction, said flow guide including a plurality of fins parallel to the axial direction and disposed around said container. 
     In accordance with one embodiment, said removable assembly comprises all or part of an air mixer chamber, said air mixer chamber extending all around said container. In one embodiment the removable assembly comprises an upper wall of the air mixer chamber, the upper wall extending all around the storage container. 
     According to one embodiment, said air mixer chamber includes an opening enabling connection to a ventilator. 
     In accordance with one embodiment, said air mixer chamber includes a fan and an electric connector, said fan being positioned in such a manner as to generate a flow of air in said air mixer chamber, said electric connector being intended to be associated with an electrical connector in a fixed part of the diffusion device to power the fan. For example the air flow rate of the fan may be between 0.2 and 60 m 3 /h. 
     In accordance with one embodiment, said flow guide features a plurality of channels opening onto the mixer chamber and oriented in a direction tangential to the evaporation surface or to the intended location of the evaporation surface. 
     In accordance with one embodiment, said removable assembly includes a flange projecting around the storage container and adapted to cover an opening in a fixed part of the diffusing apparatus, said opening being intended for the insertion of said removable assembly in the fixed part of the diffusing apparatus. 
     In accordance with one embodiment, the removable assembly includes an air flow rate regulator member configured to control the fan in order to regulate a flow rate of air in said aeration chamber and/or said air flow guide. 
     The storage container may be produced in various ways. 
     In accordance with one embodiment, said storage container includes a pressurization vent establishing communication between the interior space of the storage container and the surrounding air. 
     In accordance with one embodiment, the removable assembly includes an outer storage container and an inner storage container accommodated in the exterior container, said inner storage container being connected to the distributor member via the orifice and including a vent connected to the atmosphere at an end opposite the orifice, a communication opening between the outer storage container and the inner storage container being provided in the mouth zone in the vicinity of the orifice, the outer storage container having no opening other than the communication opening. One or more cellular retaining members is or are preferably disposed in the inner storage container and/or the outer storage container. 
     In accordance with one embodiment suitable for a diffusing apparatus the fixed part of which includes the distributor member, the removable assembly includes a stopper, said stopper being disposed to close said orifice in sealed manner during transportation of said removable assembly. For example, when the apparatus is not being used, that is to say before the container has been connected to the distributor member or after it has been disconnected from the distributor member, a storage container of this kind may be provided with a stopper arranged on the drain orifice. 
     In accordance with one embodiment the removable assembly includes a seal arranged around the orifice in such a manner as to establish a sealed connection between the storage container and the distributor member. 
     In accordance with one embodiment, the removable assembly includes a mechanical retaining means enabling stabilization of the removable assembly in said fixed part of the diffusing apparatus. For example, the removable assembly is mounted in said fixed part of said diffusing apparatus by screwing or clipping. 
     In accordance with one embodiment, the storage container has no opening other than the orifice, said storage container containing, as well as the liquid substance, a gas phase occupying at least 20% of the volume of the storage container. 
     In accordance with one embodiment, the removable assembly comprises a mechanical polarization means to facilitate the insertion of the removable assembly in its operating position into the fixed part of the diffusing apparatus. 
     In accordance with one embodiment, said porous body is configured to establish a thermal junction with heating elements of the diffusing apparatus. 
     In accordance with one embodiment, said removable assembly is arranged as a contact junction between the cellular retaining member and the distributor member during its insertion into the fixed part of the diffusion device. 
     In accordance with one embodiment, the orifice of the container connected to the distributor member is oriented downward, that is to say in the direction of the acceleration due to gravity, when the apparatus is in its position of use. 
     The present invention also has for object a diffusion apparatus including said removable assembly according to any of the above embodiments and a fixed part including a casing that defines a housing in which said removable assembly is inserted in a functioning position enabling diffusion of the substance in the vapor state into the surrounding air. 
     In accordance with embodiments, said fixed part includes an external casing and essentially all the elements of the diffusing apparatus that have not been integrated into the removable assembly, namely, separately or in combination and in a non-exhaustive manner: a flow guide, a chute, a mixer chamber or chamber part, a fan, a distributor member, a heating member, a communication module, a control device, for example in the form of an electronic card, a fixing means for fixing the removable assembly in the housing, for example by clipping or screwing it. 
     A lid of the casing may be integrated into the fixed part or the removable assembly, for example in the form of a flange attached to the storage container. 
     In accordance with embodiments, the fixed part or said removable assembly includes at least one electronic regulator element configured to regulate the heating member. 
     In accordance with one embodiment, the electronic regulator element includes at least one electronic card and at least one electric resistor electrically energized by the electronic card. The electric resistor may be disposed on said electronic card or remote therefrom. 
     In accordance with one embodiment, the electronic regulator element is configured to control the heating member as a function of a setpoint temperature in the distributor member. 
     In accordance with one embodiment, the removable assembly comprises a means for identifying the substance stored in the container, for example a digital and electromagnetic means such as a radio frequency identification (RFID) chip or an analog means such as a barcode or other marking. 
     In accordance with one embodiment, the electronic regulator element is connected to a detector disposed in the fixed part and configured to detect a marking at the level of the storage container indicating the substance contained in the container and the control device determined as a function of said marking, at least one operating parameter of the device selected from the setpoint temperature, an air flow rate and time indications defining a stop/go cycle. Such time indications include for example cycle start dates, cycle end dates, cycle durations, inter-cycle duration, etc. 
     In accordance with one embodiment, the electronic regulator element includes a memory storing a table of values associating substances with setpoint temperatures. 
     In accordance with one embodiment, the fixed part further includes a communication module to provide wired or wireless communication with a data server, for example in order to modify the table of values or to update the regulation program. 
     In accordance with one embodiment, the fixed part includes housings to receive a plurality of storage containers each containing a liquid substance. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention will be better understood and other aims, details, features and advantages thereof will become more clearly apparent in the course of the following description of particular embodiments of the invention given by way of nonlimiting illustration only with reference to the appended drawings. 
         FIG. 1  represents an exploded view of a diffusing apparatus that can be produced in the form of a fixed part of a removable assembly. 
         FIG. 2  represents an exploded view in section of the diffusing apparatus from  FIG. 1 . 
         FIG. 3  represents a storage container in accordance with a first embodiment. 
         FIG. 4  represents a storage container in accordance with a second embodiment. 
         FIG. 5  represents a storage container in accordance with a third embodiment having a double storage container. 
         FIG. 6  is a perspective view that represents a storage container including a stopper in accordance with one embodiment. 
         FIG. 7  represents a distributor member with heating members in accordance with one embodiment. 
         FIG. 8  represents a removable assembly including a storage container and an air flow guide in accordance with one embodiment. 
         FIG. 9  is a perspective view that represents a removable assembly including a storage container, an air flow guide and a distributor member in accordance with one embodiment. 
         FIG. 10  is a view in section that represents a removable assembly including a storage container, the air flow guide and the chute in accordance with one embodiment. 
         FIG. 11  is a cutaway perspective view that represents a removable assembly including a storage container, an air mixer chamber, an air flow guide, a chute and a distributor member in accordance with one embodiment. 
         FIG. 12  is a perspective view that represents a removable assembly including a storage container, an air mixer chamber, a fan, an air flow guide and a chute in accordance with one embodiment. 
         FIG. 13  is a view in section that represents a removable assembly in accordance with one embodiment including a storage container, a distributor member, sealing elements and a chute. 
         FIG. 14  is a partial view to a larger scale of the removable assembly from  FIG. 9  in section taken along the line XIV-XIV. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a diffusing apparatus intended to diffuse a substance in the vapor state into the surrounding air will now be described. 
       FIGS. 1 and 2  illustrate a diffusing apparatus  1  constituted of elements represented here in an exploded perspective view. A cylindrical storage container  10 ,  110 ,  210  contains the liquid substance. The storage container  10 ,  110 ,  210  includes a cylindrical hollow body  17  closed at its upper end by a fluid-tight end-piece  11  that carries a holding tab  13  in its upper part. A lower part of the cylindrical hollow body  17  includes an orifice  12 . The orifice enables communication of the liquid substance to the exterior of the storage container  10 ,  110 ,  210 . The diffusing apparatus  1  includes an air guide part  40 . The air guide part  40  includes a flow guide  41  associated with a chute  42  intended to be arranged around the orifice  12  of the storage container  10 . An air mixer chamber  60  is intended to be positioned around the storage container  10 ,  110 ,  210  and to be in communication with the flow guide  41 . The mixer chamber  60  may extend over all or part of the height of the storage container  10 ,  110 ,  210 . A porous body  30  includes a lug  31  projecting from its upper face and is intended to penetrate the orifice  12  or to be connected thereto by a pipe that is not represented. 
     The lower part of the porous body  30  includes a heating element  32  enabling heating of the porous body  30  and an electric connector  33  intended to be connected to an electronic card  85  arranged in the casing  80 . In the position of use the electric connector  33  is connected to the electronic card  85  and/or to an energy source  86  and enables supply of electric current and/or control signals. The control signals may be generated by the electronic card  85 , for example by use of a control program defining a stop/start cycle of the heating element  32 , start of cycle dates, end of cycle dates or cycle durations. The energy supply may take various forms such as a battery, a connection to an external electrical mains supply and/or a solar panel. 
     The casing  80  includes a lid  82  including hinges  83 , a bottom piece  81  including an opening to the exterior environment and a fixing part  84 . The lid  82  may be pivoted between a closed position and an open position, which enables replacement of the storage container  10 ,  110 ,  210  when the latter has been emptied of its substance to be diffused. In the closed position the lid  82  can also come to press on the holding tongue  13  in order to retain the storage container  10 ,  110 ,  210  in the casing  80  in a stable manner. 
     In accordance with one embodiment the diffusing apparatus  1  is produced in two parts: a removable part including at least the storage container  10 ,  110 ,  210  alone or in combination with other elements, as explained hereinafter, and a fixed part including at least the casing  80  intended to receive the removable part. 
     The storage container  10  may be produced in various ways. 
       FIG. 3  illustrates a storage container  10  that includes a cylindrical hollow body  17  including an upper part closed by a fluid-tight tip  11  and a lower part including an orifice  12  and a retaining lip  19  arranged around the orifice  12 . The fluid-tight tip  11  enables the storage container  10  to be sealed after filling it. The orifice  12  enables the substance contained in the storage container  10  to flow to the porous body  30 . 
     In accordance with an embodiment represented in  FIG. 4  the storage container  110  contains two blocks of retaining foam. A first foam  111  is arranged in the mouth zone of the storage container  110  set back from the orifice  12  and a second foam  112  is situated in the storage container  110  in contact with the first foam  111 . A rod  121  extends into the container from the fluid-tight tip  120 . The rod  121  has a cruciform cross section for example. The rod  121  holds the retaining foams in position. The rod  121  exerts a pressure to maintain the second foam  112  in contact with the first foam  111 , thereby making it possible to retain the first foam  111  in the mouth zone of the storage container  110 . The first foam  111  is set back from the orifice to reduce the risks of accidental contact with exterior elements, which contact could lead to pollution, damage or waste of the liquid substance intended to be diffused. A retaining lip  19  is arranged around the orifice  12 . The retaining lip  19  reduces the size of the orifice  12  and enables retention of the cellular retaining member  111  set back from the orifice  12 . 
       FIG. 5  illustrates a storage container  210  in accordance with another embodiment. The storage container  210  includes an outer storage container  211  that is totally closed if it is not at its end in contact with an inner storage container  212 . The inner storage container  211  is surmounted by a vent  213  at its upper end. The vent  213  enables balancing of pressure between the air outside and inside the inner storage container  212 . The inner storage container  212  contains a cellular retention member, for example a sponge or a cellular foam, that is intended to come into contact with the porous body (not represented here) through the orifice  12 . A retaining lip  19  is arranged around the orifice  12  and enables retention of the cellular retaining member  111  set back from the orifice  12 . Thus as each drop flows to the porous body the pressure in the inner storage container  212  is balanced via its vent  213  and leads to a drop in level. By communicating via the junction  214  between the two storage containers, the outer storage container  211  refills the inner storage container  212 , but the depressurization of the outer storage container  211  then increases in the part of the storage container where there is no or no longer any liquid. Thus the inner storage container  212  is balanced with the depressurization of the outer storage container  211 . The inner storage container  212  is nevertheless always able to exit this equilibrium state thanks to its vent  213  and the traction produced by the porous body of the distributor member (not represented here). For the flow to be able to occur normally, when placing the storage container  210  in the fixed part of the diffusing apparatus, the outer storage container  211  is completely filled with the substance. 
       FIG. 5  also shows that a flange  90  may be arranged projecting around the storage container  210  and adapted to cover an opening of a fixed part of the diffusing apparatus during its insertion. In this case, the fixed part of the diffusing apparatus does not necessarily include a lid. The flange  90  can be positioned at will anywhere on the length of the container  210 . 
     The fixed part may contain all or part of a mixer chamber, as sketched at  88 . In accordance with one embodiment, the flange  90  constitutes the upper wall of the mixer chamber  88  to close the latter when the removable assembly is inserted in the operating position. Alternatively, the upper wall  90  could be rigidly connected to the fixed part rather than the removable assembly. In this case, the storage container  210  comes to close the mixer chamber  88  on being inserted into a central opening in the upper wall  90  the diameter of which is equal to the outside diameter of the storage container  210 . 
     Referring to  FIG. 6 , the opening  12  of the storage container  10 ,  110 ,  210  is equipped with a stopper  50  in order to prevent the liquid substance contained in the storage container  10 ,  110 ,  210  flowing out when the storage container is not being used and/or when it is being transported. This stopper  50  includes a ring  51  supporting an O-ring. The stopper  50  may be fixed on by screwing it on or by clipping it on for example. The use of a stopper facilitates the transportation of the container  10 ,  110 ,  210  and makes it possible to avoid potentially costly losses of substances. The sealed stopper enables losses of substance to be avoided even in the event of dropping, an impact or other disturbance. 
       FIG. 7  represents an embodiment of the porous body  30 . The porous body  30  includes a main part  300  that has a cylindrical shape surmounted by a lug  301 . That lug enables the substance to be conveyed toward the main part  300  of the porous body  30 . On the side of the porous body  30  opposite that carrying the lug  301  two recesses  302  are formed in order for each to receive a heating element  132  and/or a temperature sensor. The heating elements  132  are electric resistors supplied with power by an electric circuit  185 . The temperature sensor may be a thermistor. The peripheral surface of the main part  300  forms an evaporation surface  39  onto which open microchannels formed by the porosity of the porous body  30 . 
     The porous body  30  may be integrated into the removable assembly with the container  110  or  210 . In this case, the lug  301  will be inserted in the orifice  12  to compress the cellular retaining member situated in the mouth zone of the storage container  110 ,  210 . The porous body  30  may equally well have a uniform or non-uniform porosity. The open porosity is preferably 25% in the core and 45% at the surface. This will then be a porous body in which the open porosity, that is to say the volume of the pores per unit volume of the porous body, increases from the core toward the evaporation surface, this structure favors greater spreading over the entirety of the surface of the porous body from the outlet of the pores and strengthens the mechanical integrity of the porous core with a more dense core. 
     The  FIG. 8  embodiment illustrates a removable assembly  800  including a storage container  10 ,  110 ,  210  and an air flow guide  41  situated at the periphery of the orifice  12 . The air flow guide  41  is intended to guide a flow of air in a particular direction. This removable assembly  800  is intended to be mounted in the first part of the diffusing apparatus including in particular an airflow generator and a distributor member. The air flow generated by the air flow generator in the direction of the air flow guide  41  will then be guided in the direction of the distributor member of the fixed part of the diffusing apparatus. 
       FIG. 9  illustrates an embodiment of a removable assembly  900  that includes in addition to the elements from  FIG. 8  a porous body  130  connected to the orifice  12 . The porous body  130  is intended to be connected to heating elements situated in the fixed part of the diffusing apparatus. The diffusion of the substance may be regulated by controlling the temperature of the porous body  130  using one or more heating members integrated into the fixed part of the diffusing apparatus. The air flow guide  41  includes a plurality of parallel fins  43  delimiting channels  44  enabling the flow of air to be guided in the direction of the porous body  130 . 
     The  FIG. 10  embodiment represents a removable assembly  1000  comprising a storage container  10 ,  110 ,  210  associated with an air flow guide  41  situated at the periphery of the orifice  12  and a tubular chute  42  fixed to the air flow guide  41 . The chute  42  is a body of revolution the interior space  45  of which has a convergent and then divergent section. The smallest section is located approximately at the level of the half-length of the porous body  30 . An upper rim  46  of the chute  42  comes to be attached around the flow guide  41 , for example by clipping it on. The chute  42  enables the flow of air to be guided over the porous body  30 , favoring evaporation of the substance in the required direction, namely toward the bottom of the casing  80 . In this embodiment the porous body and the air flow generator may be situated in the fixed part of the diffusing apparatus. 
       FIG. 11  and  FIG. 12  illustrate a removable assembly  1100  including a container  10 ,  110 ,  210 , an air mixer chamber  60  arranged around the storage container  10 ,  110 ,  210 , an air flow guide  41  including a plurality of fins  43 , and a chute  42 . The fins  43  are parallel to the axial direction and disposed around said storage container  10 ,  110 ,  210 . The air mixer chamber  60  may include a fan  61 . 
     The porous body  30  carries an electric heating element  32 . An electrical junction  33  enables connection of the electric heating element  32  to a power supply circuit situated in the fixed part of the diffusing apparatus. 
     In operation, the electric heating element  32  will cause heating of the porous body  30 , reduction of the viscosity of the liquid substance and consequently flow of the liquid substance from the mouth of the storage container in the direction of the distributor member. The liquid therefore rises to the top of the pores of the porous body  30  by capillarity, which together constitute the evaporation surface that is therefore situated at the periphery of the porous body  30 . 
     When a flow of air penetrates the air mixer chamber  60  it is then directed via the air flow guide  41  and the chute  42  tangentially onto the evaporation surface  39  to cause evaporation of the substance on the surface and its transportation in the vapor state in the direction of the flow of air. 
     The capillary force is caused by the nature of the surface, which is made up of channels or pores sufficiently narrow to generate capillary traction. The capillary traction and retention force must enable the liquid to rise to the top of the pores of the evaporation surface  39 ; however, this must occur without allowing uncontrolled spreading over the evaporation surface  39  by forces due to the gravity field (terrestrial attraction and hydrostatic pressure of the liquid column potentially present) or static attraction forces generated by interactions between the solution and the rest of the surface of the porous body  30 . 
     This capillary traction exists only by renewal of the final volume block (the cylindrical liquid section at the top of the pore). This volume is renewed by evaporation and is governed by the equilibrium of the concentrations of liquid and gas molecules at the liquid and gas interface in accordance with a parameter specific to each solution and depending mainly on temperature (at atmospheric pressure), namely the saturated vapor pressure. Increasing the temperature of the solution to be evaporated leads to an increase in the saturated vapor pressure, and therefore movement of the equilibrium of the liquid and gas molecule concentrations at the interface toward the gas molecules: evaporation continues until equilibrium is established again. If the gas phase is mobile, equilibrium is never achieved and evaporation continues until the liquid phase is exhausted. The more mobile the gas phase (the faster molecules tend to be evacuated to the gas phase), the faster the evaporation. 
     In the position of use the fan  61  remains connected by electronic junction to the electronic card  85  and an electric energy generator  86 . The fan  61  generates a flow of air in the mixer chamber  60  in a direction perpendicular to the fins  43  of the flow guide. The flow of air is disturbed and undergoes a change of direction at the fins  43  of the flow guide  60  and penetrates the chute  42 , after which the flow of air is directed toward the porous body  30  including the heating element  32 . As explained above, heating the porous body  30  is going to decrease the viscosity of the substance and with the flow of air this will enable evaporation of the substance into the exterior environment. In a variant of this embodiment, the fan  61  is mounted in the fixed part of the diffusing apparatus and there is an orifice in the mixer chamber  60  enabling integration of the fan  61  when the removable assembly is mounted in the fixed part of the diffusing apparatus. 
       FIG. 13  represents a removable assembly  1300  including a container  10 ,  110 ,  210 , a flow guide  41  and a chute  42  situated all around the porous body. The flow guide  41  and the chute  42  may be formed in one piece. A double seal is provided between the container  10 ,  110 ,  210 , the chute  42  and the porous body  30 . A sealing element  70  is situated between the container  10 ,  110 ,  210  and the chute  42  and a sealing element  71  is situated between the chute  42  and the porous body  30 . The porous body  30  includes two recesses  402  each shaped to receive a heating element  132  and/or a temperature sensor. In this embodiment, in the position of use the two recesses of the removable assembly come to nest with two heating elements  132  of the fixed part of the diffusing apparatus. 
       FIG. 14  illustrates a section of the removable assembly  900  including a storage container  110 , an air flow guide  41  and a porous body  30 . The porous body  30  is inserted in the orifice  12  of the container  110  until it comes to compress the cellular retaining member  111 , then forming a contact junction. The flow guide  41  is arranged around the storage container  110  at the level of the junction between the storage container  110  and the porous body  30 . An O-ring  72  is fitted at the level of the junction between the storage container  110  and the porous body  30 . Another seal  47  may be accommodated in a groove  48  in the flow guide  41 . In the position of use the seals make it possible to constrain the liquid to flow in the direction of the porous body  30  without any associated substance leak. The seals may be single, double, radial and/or compressive, for example. 
     Although the invention has been described in connection with particular embodiments it is obvious that it is in no way limited to them and that it encompasses all technical equivalents of the means described and combinations thereof if the latter fall within the scope of the invention. 
     The use of the verb “include” or “comprise” and conjugate forms thereof does not exclude the presence of elements or steps other than those stated in the claim. 
     In the claims, any reference sign between parentheses should not be interpreted as a limitation of the claim. 
     EXAMPLES 
     A number of embodiments of the diffusing apparatus  1  have been constructed and tested. 
     Experiment 1 
     The active molecule used is (7E,9Z)-Dodeca-7,9-dienylacetate having a flash point of 137° C., a mass per unit volume (at 20° C.) of 0.903 g/cm3, a viscosity of 8 mPa·s at 23° C. and a saturated vapor pressure of 0.15 Pa at 15° C. 
     The composition studied comprises:
         99.5% by weight of (7E,9Z)-Dodeca-7,9-dienylacetate, and   0.5% by weight of BHT (butylated hydroxytoluene).       

     This compound is known under the product name Rak® 2 New and will be used in the storage container for this experiment. 
     Three systems were studied: 
     The porous body is a sintered alumina ceramic wick having a pore size of 100 nm and a uniform porosity of 40%. 
     System 1: 
     The evaporation area of the wick is 7.9 cm 2 , the wick has a diameter of 2.3 cm (centimeters) and a height of 1.2 cm. The mean velocity of the flow of air around the surface is 0.2 m/s. The outside temperature is 25° C. 
     System 2: 
     The evaporation area of the wick is 15.5 cm 2 , the wick has a diameter of 2.6 cm (centimeters) and a height of 1.9 cm. The mean velocity of the flow of air around the surface is 0.45 m/s. The outside temperature is 25° C. 
     System 3: 
     The evaporation area of the wick is 22.8 cm 2 , the wick has a diameter of 2.8 cm (centimeters) and a height of 2.6 cm. The mean velocity of the flow of air around the surface is 0.50 m/s. The outside temperature is 25° C. 
     
       
         
           
               
               
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 Control temperature 
                 Ambient 
                 52° C. 
                 58° C. 
               
               
                   
                   
               
               
                   
                 RAK 2 evaporation 
                 0 
                 1.9 
                 3.8 
               
               
                   
                 (mg/h) on System 1 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 System 
                 System 1 
                 System 2 
                 System 3 
               
               
                   
                   
               
               
                   
                 Evaporation area 
                 7.9 
                 15.5 
                 22.8 
               
               
                   
                 (cm 2 ) 
               
               
                   
                 RAK 2 evaporation 
                 3.8 
                 8.9 
                 12.2 
               
               
                   
                 (mg/h) at 58° C. 
               
               
                   
                 Non-evaporation 
                 33 
                 33 
                 33 
               
               
                   
                 threshold 
               
               
                   
                 temperature ° C. 
               
               
                   
                   
               
            
           
         
       
     
     The measurements are conducted in accordance with a relative mass loss protocol of the system, considering (by visual observation) that any loss of mass arises from evaporation followed by expulsion of the molecules out of the system. 
     Experiment 2 
     The molecule used is isopropyl myristate having a flash point of 160° C., a mass per unit volume of 0.855 g/cm3 at 20° C., a dynamic viscosity of 5.58 mPa·s at 20° C. and a saturated vapor pressure of 100 Pa at 20° C. 
     System 1: 
     The evaporation area of the wick is 7.9 cm 2 , the wick has a diameter of 2.3 cm (centimeters) and a height of 1.2 cm. The mean velocity of the flow of air around the surface is 0.2 m/s. The outside temperature is 25° C. 
     System 2: 
     The evaporation area of the wick is 15.5 cm 2 , the wick has a diameter of 2.6 cm (centimeters) and a height of 1.9 cm. The mean velocity of the flow of air around the surface is 0.2 m/s. The outside temperature is 25° C. 
     System 3: 
     The evaporation area of the wick is 15.5 cm 2 , the wick has a diameter of 2.6 cm (centimeters) and a height of 1.9 cm. The mean velocity of the flow of air around the surface is 0.45 m/s. The outside temperature is 25° C. 
     
       
         
           
               
               
               
               
               
             
               
                   
               
             
            
               
                 Control temperature 
                 Ambient 
                 50° C. 
                 60° C. 
                 70° C. 
               
               
                   
               
               
                 Isopropyl myristate 
                 0 
                 8.9 
                 23.1 
                 45.5 
               
               
                 evaporation (mg/h) 
               
               
                 on System 1 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 System 
                 System 1 
                 System 2 
                 System 3 
               
               
                   
                   
               
               
                   
                 Evaporation area 
                 7.9 
                 15.5 
                 15.5 
               
               
                   
                 (cm2) 
               
               
                   
                 Isopropyl myristate 
                 19.5 
                 21.1 
                 44.4 
               
               
                   
                 evaporation (mg/h) 
               
               
                   
                 at 55° C. 
               
               
                   
                 Non-evaporation 
                 36 
                 36 
                 36 
               
               
                   
                 threshold 
               
               
                   
                 temperature ° C. 
               
               
                   
                   
               
            
           
         
       
     
     The measurements are conducted in accordance with a relative mass loss protocol of the system, considering (by visual observation) that any loss of mass arises from evaporation followed by expulsion of the molecules out of the system.