AU2012202798A1 - Device to regulate the moisture and temperature on the surface of a support element - Google Patents

Abstract

This invention concerns a moisture and temperature control device (1) on the surface of a support element (3) of the mattress or cushion type and near and in contact with the body (13) of an individual lying there, comprising a casing formed by at least two parts (11, 12) defining an interior chamber (13), said two parts consisting of a first part (11) intended to be placed on the side of said body of the individual, and a second part (12) intended to be placed on the side of said support element (3) of such mattress or cushion type, said first part being made of a material forming a barrier impermeable to air and to liquid water and permeable to water vapor, said second part being made of a material permeable to water vapor, said second part comprising at least one air injection port (4) and air evacuation means comprising perforated or porous areas permeable to air, preferably perforations (5), wherein said inner chamber (13) comprises capsules (4) of phase change materials) (PCM), whose lowest crystallization temperature is higher than 250C and the highest melting temperature is lower than 400 C, said capsules being integrated within and/or placed on the surface of an air-permeable support (2,3). Figure 1 5a 5 2b 32a 2a . 2a 2a 1 1a 112a 13 21 22 2b l lb 1le1 1lb 61, 5 12 13 FIG.3 77

Description

- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Hill-Rom Industries SA Actual Inventor: Laetitia Gazagnes Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: Device to regulate the moisture and temperature on the surface of a support element The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 74878AUP00 -2 DEVICE TO REGULATE THE MOISTURE AND TEMPERATURE ON THE SURFACE OF A SUPPORT ELEMENT FIELD OF THE INVENTION [0001] The present invention concerns the technical field of support devices such as mattresses or cushions to support the body of a person sitting or lying on the support device, and specifically devices such as support therapeutic mattresses to support the body of patients. [0002] The invention relates more particularly to a therapeutic mattress cover on which an individual may be lying under conditions of thermal comfort and optimal moisture control, the cover ensuring an optimal microclimate for the patient, the cover also ensuring a regulation of the microclimate under optimal temperature conditions for the patient. [0003] More specifically, this invention relates to devices and methods of regulation of the moisture and temperature on the surface of a support element such as a mattress or cushion in the vicinity and contact of the body of an individual lying on them. BACKGROUND TO THE INVENTION [0004] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. [0005] Moisture may originate from the body of the patient by the flowing of a bodily liquid such as sweat, or an external source of spilled liquid. It is desirable indeed to avoid the maceration of the liquid at the level of the soft tissues of the skin, whether it is external liquid or sweat, because this humidification causes maceration which favors the formation of bedsores and causes infectious points. [0006] We know methods and devices of this type, consisting of injecting air at the surface or towards the body of the individual, by implementing so-called "low-air-loss -3 bed" mattresses or cushions constituted of compartments filled with air under pressure. Thus, the body of the individual or the area between the body and the support element, i.e. the mattress, at the level where it can create moisture, is dried by the airflow sent in this direction. [0007] A primary problem of this known device is that it cannot be implemented independently of the support element, especially the mattress, and that the interruption of the air injection inside the mattress makes it useless. Another disadvantage of this low-air-loss mattress system is that it can lead to excessive drying of the body and requires compensation of water loss by a program of hydration of the individual. [0008] Dehumidification systems in the vicinity of a patient have been described, consisting of a cover comprising a casing interposed between the patient and the mattress, said casing comprising an upper layer and a lower layer defining a chamber in which air is circulated. In these systems, it is desired to dehumidify the outer surface of said upper layer on which said patient rests, at least in part by transfer of water vapor by molecular migration of water molecules through the upper layer of the cover permeable to water vapor. [0009] In US 5.882.349, the lower layer of the casing is impermeable to air and water vapor and air is injected where appropriate in only part of the internal volume of said casing by a plurality of injection ports, and is discharged through a plurality of perforations that may be arranged on the sides of the upper layer. This dehumidification system is relatively inefficient with an announced dehumidification of only 400 ml/24h. [0010] In US 5.926.884, a mattress cover of this type is described, in which the air is exclusively evacuated through perforations in the upper layer on the entire surface, and especially at the level of the zone covered by the patient, and the lower layer is permeable to water vapor. The casing so formed between the lower layer and the upper layer, both permeable to water vapor, is completed by an additional underlying layer that absorbs and disperses the water vapor that risks accumulating between the dehumidification device so formed and the mattress.

-4 [0011] In these dehumidification devices, by transfer of water vapor, the evacuation of the air, at least in part on the side of the patient lying on the device, has the risk of contamination of the casing by penetration of liquid or another contaminant from the outer surface of the upper layer on which the patient lies. Secondly, and most importantly, the yield in terms of dehumidification are either relatively small or are accompanied by dehydration of the patient resulting from excessive airflow sent close to the patient. [0012] EP 1.915.978 in the name of the applicant describes a new procedure and device for moisture regulation on the surface or in the vicinity of the body of an individual lying on a support element of the type of a mattress or cushion which do not present the above inconveniences and are more performing in terms of dehumidification yield. [0013] In particular, in EP 1.915.978, the device and method can be implemented independently of said support element and particularly on any type of air or foam mattress, or other, which offers all safety guarantees to the risks of contamination with a fluid coming from outside, and not requiring a concomitant hydration of the patient. [0014] The device in EP 1.915.978 provides an automated moisture control and not simply a device that allows only the continuous reduction of moisture like the devices of low air loss mattress of the prior art. [0015] More precisely, in EP 1.915.978 a moisture control device is provided on the surface of a support element of the mattress or cushion type, in the vicinity of the body of an individual lying there, including a casing formed by at least two parts linked between them on their peripheral edges, preferably sealed by welding, defining an interior chamber, said two parts consisting of a first part or top part, intended to be arranged on the side of said body of the individual, and a second part or lower part, intended to be arranged on the side of said support member of mattress or cushion type, said first part being constituted of a material forming an impermeable barrier to air and liquid water and permeable to water vapor, and said second part being made of a permeable material to water vapor, whereby said second part comprises at least one air injection port and air discharge means comprising air-permeable perforated or porous areas, preferably perforations.

-5 [0016] It is understood that said first part is not perforated and the air is exclusively evacuated through said second part wedged between said first part and said support element of the mattress or cushion type. [0017] In the case of a mattress disposed horizontally on a bed, said first part constitutes an upper part on which the body of the individual lies, and said second part constitutes a lower part applied on the mattress and arranged below said first part or upper part. [0018] A device as described in EP 1.915.978 provides a satisfactory control of moisture, particularly when used on therapeutic mattresses for patient care. However, it has a thermal efficiency limit because the measured curve of temperatures of the skin of the patient lying in bed on these devices increases with time and exceeds the critical comfort temperature of 35 0 C, beyond which the bedridden patient is in a state of risk of occurrence of decubitus ulcers in areas at risk of the body, such as the areas of the sacrum and heels for example. [0019] Another problem is that if the temperature of certain patients drops, especially with certain illnesses, below the lower limit temperature of 28*C, the patient's health is in danger. [0020] The purpose of this invention is therefore to provide a device and method that allows simultaneous monitoring of the patient's moisture in the contact area with the mattress on which he rests, on the one hand, and, on the other hand, controlling the temperature of the patient's skin in contact with the mattress, so that it does not exceed an upper limit of preferably 35 0 C, which is the limit of comfort temperature and does fall below a lower limit temperature, preferably 28 0 C, which is the lower limit of comfort temperature. The device according to the invention thus reduces the occurrence of pressure ulcers resulting from the combination of the excessive moisture and temperature mentioned above. [0021] There are known materials with phase change, hereinafter PCM materials, especially fabrics coated with microcapsules of PCM materials, hereinafter PCM fabrics (e.g. marketed by the companies Outlast Technology (USA) or Schoeller Textil (Switzerland). These fabrics are used in clothing to protect against excess heat by -6 absorbing heat when the body produces too much or releasing it when the body is cooled. As is known, the microcapsules of PCM materials can be integrated into the fabric and even within the constituent fibers of the fabric or coated on the surface of the fabric in a coating. This technology was originally developed for NASA to protect astronauts from major temperature fluctuations in space. [0022] The inventors have tried to implement such a PCM fabric juxtaposed over a humidity control device as described above. However, they observed that this provision seemingly obvious and optimal to reduce the temperature, affected not only the effectiveness of regulating the reduction of moisture in contact with the patient's body, but was also less effective in limiting the rise in patient's temperature at the areas of contact with the device according to the invention. SUMMARY OF THE INVENTION [0023] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. [0024] To this end, the inventors have discovered that, surprisingly, the optimal implementation of a PCM fabric in combination with a moisture and temperature control and regulation device required to implement the PCM fabric under specific conditions of exposure to an airflow, which conditions were not met in case of direct contact of the PCM fabric with the patient's body, placed between the patient and the moisture control device as described above. [0025] More precisely, this invention provides a moisture and temperature control device on the surface of the support element of the mattress or cushion type and in the vicinity of and in contact with the body of an individual lying there, including an casing formed by at least two parts preferably linked between the mat the level of their peripheral edges, preferably linked by welding, defining an internal chamber, said two parts consisting of a first part intended to be arranged on the side of said body of the individual, and a second part intended to be arranged on the side of said support member of mattress or cushion type, said first part being made of a material forming an air-impermeable barrier air and liquid water and permeable to water vapor, said second part being made of a material permeable to water vapor, said second part comprising -7 at least one air injection port and air discharge means comprising perforated or porous air-permeable areas, preferably perforations, characterized in that said interior chamber comprises capsules of phase change material(s) (PCM), whose lowest crystallization temperature is higher than 25C, preferably above 28*C and the highest melting temperature is lower than 40*C, preferably lower than 35*C, said capsules being integrated into and/or arranged on the surface of a support, preferably a support consisting of a woven or non-woven fibrous material, permeable to air. [0026] More particularly, the PCM microcapsules have a diameter of 5 Lm to 5 mm. [0027] It is understood that the PCM capsules are distributed in and/or at the surface of said air-permeable support at least in the contact areas of the body with the device according to the invention, so that at least said contact areas are regulated in moisture and temperature, namely the contact areas of the following body parts: head, the dorsal area, the sacrum and heels area, when a patient lies on top of a device according to the invention applied on a mattress. [0028] When the device according to the invention operates, the airflow circulates inside between the lower part and the upper part; the PCM capsules are initially in solid phase in normal temperature and pressure conditions (25"C, 1 atm). [0029] When the patient is in bed for a few minutes, the temperature of the surface of his skin will tend to increase due to heat accumulation. Thus, the skin temperature will increase and tend towards uncomfortable temperatures beyond 35*C; then the patient is in indirect contact with the PCM capsules whose temperature change phase is between 20 and 40*C, on contact, the PCM will change their state from solid to liquid if their temperature reaches the highest melting temperature defined above. Indeed, this phase change of the material requires energy, called "latent heat," carried by the heat generated by the patient, and uses the energy available, this excess heat created by the patient. The temperature of the patient's skin is going to stabilize in a comfort zone not exceeding the limit temperature defined above, because the excess heat is evacuated.

-8 [0030] Thanks to these PCM capsules in combination with an airflow inside said chamber, a temperature gradient is created between the patient and inside the device, resulting in a spontaneous transfer of heat from the patient to the interior of the device. [0031] Conversely, if the temperature of the patient's skin is reduced because of a disease and drops below the comfort zone (below 250C, preferably 280C), the PCM in indirect contact with the patient go back from liquid to solid state by releasing a latent heat; it will warm the patient to maintain him in the comfort temperature range above 25*C, preferably 28*C. [0032] A balance is thus created within the device and the surface of the patient's body: the skin temperature does not exceed 40*C, preferably 350C and stabilizes in a comfort zone between 25 and 40*C, preferably 28 and 350C. The patient's body temperature is also controlled, the temperature differences become very limited. [0033] On the other hand, when the patient lies down on the operating device, it creates high humidity in the upper part near the patient. Thus, a moisture gradient is created between the top of the upper layer and underneath this layer; water molecules in vapor phase will therefore pass through the upper layer, from the patient towards the inside of the device. Indeed, this upper part allows migration of water molecules in the vapor phase due to the chemical nature of the molecules of said upper part. Positive and negative charges alternate on the molecules of the top part and water vapor molecules may interact with the molecular chain, in particular the polyurethane of the upper part by hydrogen bonding, and thus move along this molecular chain. Thus, they go through the top part and find themselves inside the device. They are then driven away by the airflow. In the end, there is a reduction of moisture of the patient. [0034] The airflow within said chamber increases the efficiency of the PCM by absorbing part of the heat energy from the patient. On the other hand, the heat absorption by the PCM contributes to increased moisture decrease due to the reduction of the patient's perspiration. Consequently, there is a synergistic effect between the specific means of moisture reduction that are said first and second parts and airflow and the specific means of temperature control that are said PCM capsules.

-9 [0035] The combination of humidity regulation and temperature control with the device according to the invention thus significantly reduces the risk of pressure ulcers according to the purpose of the invention. [0036] Another advantage of the device according to the invention is the ability to regulate or control the temperature without having to implement a device for heating and/or cooling of the injected air and/or air to within said chamber, requiring a supply of energy to operate. [0037] As is known, the phase change materials can be organic materials such as fatty alcohols or fatty acids, glycols, or preferably paraffinic hydrocarbons or inorganic PCM, such as hydrated salts. And as is known, PCM capsules or microcapsules of 10 pLm to 5 mm have a hollow spherical polymeric wall which is 1 to 50 pm thick. [0038] More particularly, said capsules are microcapsules with diameters between 10 to 500 pm, preferably 25 to 100 pm, fixated, preferably at regular spaces, within and/or preferably on the upper surface of a so-called air-permeable support. [0039] Preferably, said PCM are paraffinic hydrocarbons having at least one chain in C-14, of which a first PCM whose phase change temperatures are between 250 and 30C, preferably alkane, and a second PCM whose phase change temperatures are between 30* and 35*C, preferably lycosane. [0040] Preferably, it comprises at least two PCM-type materials, of which a first PCM whose crystallization temperature is lower than that of the second PCM, comprised between 25* and 30 0 C, preferably between 28 0 and 30'C and a second PCM whose melting temperature is higher than the melting temperature of the first PCM and comprised between 30* and 40*C, preferably between 32* and 35*C. [0041] Still more particularly, said PCM microcapsules are applied above and/or within a so-called support constituting an intermediate layer permeable to air and to water vapor, forming a fabric referred to as 3D fabric or constituted of a nonwoven highly porous fibrous material, said intermediate layer being thicker than said first and second parts, preferably from 5 to 50 mm thick.

-10 [0042] Here we understand by 3D fabric known materials in three dimensions, unlike the current textiles that are woven in two dimensions (flat); therefore they have a certain thickness, corresponding to the weaving of the third dimension. These materials have high porosity by their constitution and are therefore permeable to air. Finally, as mentioned above, they provide a technical effect of mechanical protection of PCM microcapsules. [0043] This thick intermediate layer also favors the spacing of said first and second parts and facilitates air circulation inside the chamber and therefore its better diffusion and better evacuation of water vapor. This intermediate part included inside the chamber also has the effect of avoiding climate bridges between said first and second parts and allow for better airflow. [0044] More particularly, said thick intermediate part consists of a layer of a nonwoven fibrous material, preferably of polyester wadding, more preferably held in shape by a holding device, especially a net and/or a grid of matelasse-type seams. [0045] The thick intermediate layer has an absorbing effect favoring a better distribution and spread of moisture and therefore a better distribution of moisture in the interior of said chamber, moisture being thus more rapidly cleared by air injected inside said chamber and inducing a more efficient dehumidification. [0046] The inventors have discovered that this embodiment is particularly advantageous since said nonwoven fibrous material allows the microcapsules to sink without crashing under the weight of the patient's body, whereas in the absence of this layer of intermediate nonwoven fibrous material, after some time it is noticed that said microcapsules are crushed under the weight of the patient's body. [0047] More particularly, the device also comprises an intermediate sheet of nonwoven fibrous material, coated at least on its upper surface with said PCM microcapsules, said microcapsules having a diameter of 10 to 500 ptm, preferably 25 to 100 tm, and being dispersed at the rate of 105 to 107 microcapsules/cm 2 , preferably 106 to 5x10 6 microcapsules/cm 2 , said intermediate sheet being thinner than said first and second parts, preferably having a surface density of 100 to 200 g/cm 2

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- 11 [0048] More particularly, said interior chamber comprises a said intermediary sheet of thin nonwoven fibrous material, coated on at least its upper face with said PCM microcapsules, said intermediary sheet being secured over the upper surface of said thicker intermediary layer of a nonwoven fibrous material, permeable to air and to water vapor. [0049] According to other characteristics of the device: - the water vapor permeability of said second part is less than that of said first part, and - said evacuation means are said perforations, arranged with respect to said injection port(s) so as to be capable of creating an airflow entering said chamber through said injection port and evacuated from said chamber by said evacuation means, preferably said perforations, throughout the volume of said chamber, when said casing is inflated by air injected continuously pressurized by said injection port, so as to create an overpressure in said chamber, and - said second part is substantially airtight between said injection port and said porous or perforated areas permeable to air, the latter being arranged sufficiently far away from said injection port(s) for substantially the entire volume of said chamber to be crossed by circulating air between said injection port(s) and said porous or perforated areas. - said first part consists of a porous or perforated substrate non-impermeable to water and air, said substrate being coated on at least one side with a continuous layer of polymer, preferably polyurethane, not permeable to liquid water and air, and having molecular transfer properties of water vapor, et - said second part consists of a fabric coated on at least one of its faces with a layer of polymer, preferably polyurethane, having properties of molecular transfer to water vapor, preferably on the face facing the side within said chamber. [0050] For said first part, a or perforated porous substrate such as a fabric resulting from weaving fibers or threads has porosities or perforations not creating a barrier to the passage of water vapor transferred through the layer of polyurethane polymer. [0051] Polymers and textile materials of this type with transfer of water vapor are known to the man of the art and commercially available and used, particularly in the garment industry for their breathing quality and body disposal/regulation of sweating.

- 12 [0052] This property of molecular water vapor transfer of said polymers results from molecular affinity inducing attraction of water molecules on the molecular chains of the polymer, particularly polyurethane, comprising hydrophilic groups, said water molecules being able to go along the polymer chain and cross through the layer of said polymer. [0053] Advantageously, said second part consists of a fabric coated on at least one of its faces with a layer of polymer permeable to water vapor, i.e. having molecular transfer properties of water vapor, preferably on the side turned towards the interior of said chamber. [0054] In a preferred embodiment, said first and second parts are connected together on their peripheral edges by welding, directly with each other, or via a connecting strip coated with a polymer layer, the different polymer layers of said first and second parts and of said strip, where appropriate, being welded together by heat sealing or welding by irradiation, preferably high-frequency irradiation. [0055] In particular, the different polymer layers are of the same chemical nature, or of a chemical nature suitable to permit them to be welded together, which is the case of polyurethane polymers. [0056] Said two parts may be polymer-coated on both sides, and be sealed to one another directly. The two parts are preferably, for economic reasons, polymer-coated on one side only. And, if at least one of the faces of the two parts is not polymer coated, in particular if the first part is polymer-coated on its outer face and the second part on its inner face, the edge of one of the two parts can be folded on itself so as to have its face polymer-coated towards the inside of said chamber. [0057] In one embodiment, it is also possible to advantageously implement a peripheral connecting strip eventually folded on itself, providing the link by welding between the two said first and second parts, said strip being itself coated on one side at least with a layer of polymer which can be welded with the polymer layers of the two said first and second parts, the polymer layer of said strip being of the same impermeable nature to liquid water, air and water vapor as that of said second part.

-13 [0058] Advantageously, said fabrics constituting said first and second parts are fabrics that stretch in both longitudinal and transverse directions. Specifically, this feature allows improving the distribution of body weight, i.e. on its larger surface, and the fabric hugs the body shape and does not generate localized areas of excessive compression of the body that can generate vascular blockages and resulting diseases. [0059] Advantageously, said air evacuation perforations are arranged on the periphery of said second part. These peripheral areas do not coincide with the central area of the casing with which the body is normally in contact, but around it, thereby facilitating the evacuation of the air through said perforations. [0060] In a preferred embodiment, said second part is of substantially rectangular shape and the device comprises a single injection port near the middle of a longitudinal edge of said second part, said air evacuation perforations being disposed near the side edges and the longitudinal edge opposite to that of the injection port. [0061] Thus, the injection port is disposed relative to said evacuation perforations so as to make air circulate well throughout the inner chamber of the casing and drain out as quickly as possible the moisture transferred from the vicinity or the surface of the body towards the interior of said chamber. [0062] This invention also provides a method for controlling the temperature and moisture on the surface of a support element such as a mattress or cushion and in the vicinity and contact of the body of an individual lying there, using a device according to the invention, characterized in that it performs steps in which: 1) said casing is placed flat between said support element and said body of an individual, so that said first part is turned towards the body of the individual and said second part is turned towards said support element, and 2) air under pressure is injected into said chamber by said injection port at a pressure and at a rate such that said casing is inflated in overpressure despite the evacuation of air by said evacuation means, preferably by said perforations and the support of the body on said casing, said air overpressure inside the casing relative to the outside being sufficient to allow air circulation throughout the volume of said chamber.

- 14 [0063] It is understood that the air is injected at a pressure and at a rate such that the air within the chamber is in overpressure versus the air outside the room. [0064] By the properties of water vapor permeability of said first part, a transfer of water vapor takes place through said first part when a relative humidity gradient exists between the outer surface of said first part of the casing and the interior of said chamber, especially in case of maceration of a liquid or sweating of the body or close to the body between the body and said casing, which is accompanied by a dehumidification of the surface of said first part. When the humidity is equal on both sides of said first part, i.e. between the exterior and interior of said casing, there is no more relative humidity gradient and the transfer of water vapor stops automatically. But air circulation inside the casing allows driving the water vapor, evacuating it outside through said second part. This circulation promotes a decrease of the relative humidity within the casing and maintains the transfer of water vapor from outside the casing towards the inside of the casing where appropriate, as long as the moisture outside it is greater than relative air moisture within the casing and therefore than the moisture of the ambient air injected. The fact that moisture outside the surface of the casing is reduced until reaching the value of relative humidity of the ambient air injected, and the water vapor transfer is interrupted automatically at that time, avoids excessive dehydration of the skin tissues of said body. In addition, because of the permeability properties of the water vapor of said second part, the vapor transferred within said chamber can be evacuated to the outside in spite of the air circulation, which keeps and promotes the establishment of a high relative humidity gradient between the outside of said first part and the interior of said chamber. [0065] Finally, the fact that said second part is permeable to water vapor, and that the air is exclusively evacuated through said second part, provides a process of dehumidification exclusively by transfer of water vapor by molecular migration through the device, with a transfer rate of water vapor and thus dehumidification higher than in the prior art, without undue dampness below the device between said second part and the mattress, without risk of contamination by ingress of contamination or of liquid from the upper outer surface of said first part, since it is non-perforated, and finally, without requiring concomitant hydration treatment of the patient as is the case when air is evacuated from the upper layer towards the patient or close to him.

-15 [0066] Moreover, because according to this invention air is evacuated through said second part or bottom layer, the water vapor transferred to the underside of said second part or bottom layer does not accumulate between it and the mattress on which it is disposed, and is evaporated by the air evacuated, which is thus injected therein. [0067] As explained above, the addition of the PCM layer stabilizes the temperature of the skin (and therefore of the body) and consequently limits perspiration. On the other hand, there is a synergistic effect whose mechanism is not fully understood, in that the air circulation of the device surprisingly boosts the effectiveness of PCM microcapsules, resulting in a more efficient cooling than in the absence of air circulation. [0068] In a preferred embodiment of this invention, the water vapor permeability of said second part is less than that of said first part. [0069] This limited water vapor permeability of said second part avoids the accumulation of moisture between said second part and said support element and allows the evaporation of this moisture only by the airflow from said means of air evacuation in the absence of injection of additional air between said second part and said support element. [0070] Advantageously, said second part is substantially airtight between said injection port and said porous or perforated areas permeable to air, the latter being disposed sufficiently away from said injection port so that substantially the entire volume of said chamber is crossed by air flowing between said injection port and said porous or perforated areas. [0071] Advantageously, according to the invention, the ratio between the cumulative sections of the evacuation perforations and the injection ports section is selected so as to obtain a compromise between, on the one hand, the search for a airflow rate circulating through the high chamber and, on the other hand, a sufficient overpressure within the chamber. Indeed, the overpressure must be sufficient to ensure that the injected air circulates throughout the chamber volume, i.e. that the air is evenly distributed throughout the volume of the chamber. Otherwise there is a risk that the injected air is limited to travel within said chamber only between said injection port(s) - 16 and those of so-called localized perforated or porous areas corresponding to the passage of minimum pressure drop. [0072] However, we understand that the overpressure must be limited so as not to destabilize the individual's body resting on said casing. [0073] In practice, a pressure of at least 500 Pa provides a homogeneous air circulation in all directions and in particular in the area below or vis-a-vis the patient's body. [0074] On the other hand, the upper limit of airflow circulating in the chamber is related to the maximum rate of vacuum, i.e. the cumulative section of ports that can be tolerated by the material of said second part from a viewpoint of its mechanical strength. This rate should not exceed 10% in general. Furthermore, it is necessary to take into account that the positive effect of increased airflow on dehumidification performance is limited by the capacity of the water vapor transfer of said first and second layer piece. Beyond a certain airflow, the dehumidification performance is not improved. [0075] In practice, a flow rate of 20 to 50 1/min provides adequate dehumidification performance given the time of migration of water molecules for the transfer of water vapor through the polymer layers implemented as described below. [0076] More particularly, for an overpressure of 500 to 100OPa with an airflow rate of 20 to 50 1/min, the ratio of the sum of the sections of perforations or pores of said porous perforated or respectively discharge areas of air evacuation relative to the sum of the sections of the injection ports is at least 2, preferably 2 to 4. [0077] The evaporation of the surface water on the side of the patient is accompanied by a slight decrease of the temperature which promotes a reduction in sweat and, if necessary, offsets the increase in temperature resulting from the compression of the air injected. [0078] More particularly, the transfer of water vapor from said first part is at least 750, preferably 750 to 2000 g of water/m 2 /24h, further preferably approximately 1000 g -17 of water/m 2 /24h and the transfer of water vapor of the second part is less than 500 g of water/m 2 /24h, preferably 300 to 500 g of water/m 2 /24h. [0079] In a preferred embodiment of the method according to the invention, an overpressure of air is established within said chamber with respect to the exterior of the chamber, sufficient for air to circulate throughout the volume of said chamber and more particularly an overpressure of 500 to 1000 Pa is established, preferably about 750 Pa, with an airflow rate circulating in said chamber of at least 20 I/minute, preferably 30 to 50 1/min. [0080] Advantageously, the device according to the invention also comprises a device injecting compressed air supplying air to said casing by said injection port. [0081] Also advantageously, in the method according to the invention, air is injected between said second part and said support element, preferably from the same device injecting compressed air supplying said casing through said injection port. [0082] In a preferred embodiment, said support element consists of at least one inflatable compartment, filled with air, preferably connected to the same air injection device as the one supplying said casing. [0083] The air filling said chamber can thus be derived from the same air source as that inflating the mattress via a device guiding the air selectively, for example a solenoid device acting as switching device of a single air source. Said solenoid valve may be part of a module cooperating with the device according to the invention. [0084] Facilities for injecting air into an inflatable mattress have been described especially in applicant's patents EP 676.158, FR 2.751.743, FR 2.757.377, FR 2.757.378, FR 2.758.259, and FR 2.760.967. [0085] Advantageously, the device according to the invention may also include a remote control system, especially remote control, of said device injecting compressed air.

-18 [0086] More preferably, the device of the invention is incorporated into a protective cover of a said support element of mattress or cushion type, at least at the part of the cover that covers the part of the face of the support element on which at least part of the body of an individual is intended to rest. BRIEF DESCRIPTION OF THE DRAWINGS [0087] Other advantages and characteristics of this invention will become apparent from the detailed description which follows and Figures 1 to 6, in which: - Figure 1 shows a schematic longitudinal section of an inflated air mattress 13 covered with a protective cover incorporating the control device 1 according to this invention, on which a patient 14 rests, - Figure 2 shows a schematic view of four parts comprising a control device 1 according to the invention, - Figure 3 shows in cross section schematically a method of welding of the bottom part over the top part via a strip 6 forming the lateral rim 61, of a cover that ends with a closure/opening device with slide 62 and also forming a flap 63 for protecting a closing/opening device 62, - Figure 4 is a schematic representation of a fabric 2 incorporating evenly spaced microcapsules over the entire surface of the fabric 2, said fabric 2 being sewn by mattress stitching and a peripheral serging 2b over a thicker layer porous to air 3, - Figure 5 shows measurement curves of the temperature of the skin in *C under the patient lying on top of a device 1 according to the invention over a mattress 13, as a function of time (e) in seconds, [ where curve A represents an embodiment in which the device 1 comprises a PCM fabric 3 sewn over a layer of polyester wadding 2, the regulating device 1 being crossed by an airflow in the chamber 13, Oi where curve B corresponds to the same embodiment with PCM fabric 3 and airflow, but without layer of cellulose wadding 2 in the chamber 13. Oi curve C represents the same embodiment as the curve B but without the airflow, and 0 curve D represents the same embodiment as the curve A with airflow but without PCM fabric 3. - Figures 6A, 6B and 6C are perspective views (fig. 6A), in detail (fig. 68) and exploded (fig. 6C) of a second embodiment of a device 1 according to the invention, -19 that can be applied having a bottom piece 12, with a peripheral skirt 12-1, capable of covering the lateral edges of a mattress 13 on which the device 1 is applied as is, the top part 11, also comprising a peripheral skirt 11-1 thermo-welded to the upper peripheral edge of the bottom part 12. DETAILED DESCRIPTION [0088] Figures 1 to 3 show a control device according to the invention comprising a casing 1 made of two parts: an upper part or said first part 11 and a lower part or said second part 12, whose peripheral edges 1a and 1b are welded 1c together by means of a connecting strip 6 folded on itself, the weld lines 1 c following substantially a rectangular contour. [0089] The casing 1 of a control device according to this invention is incorporated into a protective cover 7 covering an air mattress 13. More particularly, the casing 1 forms the upper face of the protective cover, and a portion of the connecting strip 6 forms lateral edges 61 of the protective cover partly covering the sides of the mattress 13, said lower second part or said second part 12 being applied directly on the mattress 13. [0090] Said upper and lower parts are of substantially rectangular shape corresponding substantially to the dimensions of the mattress. The cover includes a device for closing/opening with peripheral zipper 62 along the lateral sides or edges of the cover covering the edge of the mattress, said closure/opening 62 allowing the separation of a lower part 71 of the cover and lateral edges 61 and the removal of the mattress from the cover. [0091] The top part or first part 11 consists of a polyester fabric coated on its upper extemal face with polyurethane polymer that has properties of transfer to water vapor. [0092] More specifically, these polyurethane polymers are comprised of molecular chains of polyurethane containing hydrophilic ester groups allowing to transfer water vapor by molecular migration of water molecules through physico-chemical interaction with said hydrophilic ester groups of said molecular chains.

- 20 [0093] Such fabrics coated on one side with polyurethane with transfer properties of water vapor are marketed under the brand Dartex*, particularly in the reference P510, with properties of water vapor transfer of about 1000 g of water/m 2 /24h (amount of water transferable through the coated fabric), and comprising a composition of 66% polyester and 34% polyurethane, and a grammage of 130 g/m 2 . [0094] The lower part or second part 12 consists of a polyamide-based nylon fabric coated on one face with a polyurethane coat permeable to water vapor, marketed by the company Dartex*, especially under reference P280, with a water vapor transfer rate of approximately 350 g of water/m 2 /24h, a composition of 47% polyamide and 53% polyurethane, and a grammage of 179 g/m 2 . [0095] The casing formed by the two lower and upper parts defines an internal chamber 13. Inside the chamber, a first intermediate part 2 is inserted, substantially occupying the entire volume of the chamber of substantially rectangular shape, consisting of a layer of a nonwoven material 21 of 5 to 10 mm thick, constituting a duvet based on cellulose wadding of 150 to 200 g/m 2 constituting an absorbent material permeable to air and water. One can use in particular a 3D fabric of AMES EUROPE reference Pro643/3. This interlayer has the dual property to divide and distribute the homogenized water vapor transferred inside the chamber from the outer surface of the upper part, and provide a spacer between the upper and lower parts to prevent contact between two parts, while also providing some mechanical protection of the PCM microcapsules described below. [0096] The first intermediate part of non-woven material 2 is covered with a plastic mesh 21 of tulle with polyester fibers type. A peripheral seam unites the layer of the intermediate part with said net, preferably in longitudinal and lateral grid seams, stabilizing the shape of the first intermediate part. [0097] A second intermediate part 3 consisting of a fabric, hereinafter referred to as "PCM fabric," is sewn on the upper face of the first intermediate part. The PCM fabric 3 is sewn in grid on the surface of the 3D fabric 2, so that it does not fold and does not move when one must package, for example, or wrap, bend and/or wrap the entire device for transport. The fabric PCM 3 consists of a layer of nonwoven polyester, coated with an acrylic coating containing microcapsules 4 of PCM. Said microcapsules -21 4 have a diameter 4 of approximately 40 pm. Said microcapsules consist of a spherical membrane wall of approximately 2 pm in thickness, including the PCM. The PCM fabric 3 includes more specifically about 3,000,000 microcapsules/cm 2 . The PCM included in the microcapsules is a mixture of paraffinic hydrocarbons, namely alkane and lycosane whose respective melting temperatures are approximately 28 and 33*C. [0098] This PCM fabric 3 is permeable to air and water and has a surface density (including with the PCM microcapsules) of 140 g/m 2 . [0099] A PCM fabric 3 of this type is marketed by Outlast Technology (USA) under the commercial reference 233 Outlast 901 greeley. PCM fabrics of this type are also marketed by Schoeller Textil (Switzerland). [0100] In one embodiment, air is injected so as to create an overpressure of about 750 Pa in the casing 1 with respect to outside air by establishing a balanced incoming airflow and outgoing airflow of 25 to 35 I/minute. To do this, the bottom part 12 includes an air injection port 5a in the center of approximately 9.5 mm and near a longitudinal edge of the bottom part 12, said air injection port consisting of a welded plastic connector. Perforations for air evacuation with a diameter of about 3 mm are regularly spaced 10 to 20 cm along the other three edges of the bottom part 12, i.e. the two transverse edges and the longitudinal edge opposite to that of the injection port. For a bed of about 2 m long and 90 cm wide, 48 perforations were thus made. The cumulative sections of the evacuation perforations 5 thus represent approximately double the section of the injection port 4. Thus, it compensates for losses of charge related to restrictions on the passage of air and maintains a balance between the incoming and outgoing airflow with this rate of 25-35 1/min and this overpressure of approximately 750 Pa of air in the chamber versus the outside. [0101] The air injection port 5a is supplied by a compressor 8 which also supplies the air mattress 13 by means of a solenoid valve 9 which serves as a switch controlled by a control device 10, either for the air supply 12 of mattress 13 or by the air supply 11 of the air injection port within said chamber, based on measurements of a mattress inflation pressure sensor in particular.

- 22 [0102] The control device according to the invention thus allows drying 500ml of water spread evenly over a cotton sheet with the dimensions of the mattress, i.e. about 2m 2 in 3.5 hours when said mattress is covered with a model simulating a patient's body in the presence of said first and second intermediate parts 2 and 3 and in 6 hours in the absence of said first intermediate part 2, tests have been performed in an ambient atmosphere of 40% relative humidity at ambient temperature of approximately 25 0 C. [0103] Figure 5 shows several measurement curves of the temperature of the skin under the patient 14 in contact on a mattress 13 equipped with a device for regulating the moisture and temperature 1 under the following conditions: - curve A = a device 1 comprising a PCM fabric 3 combined with a thick layer of porous cellulose wadding 2 with an airflow created as described above, - curve B = a same device 1 with a same PCM fabric 3, but in the absence of the thick layer 2 with the same airflow, - curve C = same device 1 as curve B, but without airflow, and - curve D = same device 1 as curve A, but without the PCM fabric 3 and with the same airflow. [0104] We see that only the curves A and B remain below 35 0 C over time, while for curves C and D the skin temperature exceeds 35*C after a few minutes. [0105] The comparison of curves A to D shows that: - the implementation of a PCM fabric 3 can effectively control the temperature in combination with air circulation and therefore means allowing for said airflow through said upper and lower layers in particular, and - even more so, the most important limitation of temperature (curve A) is obtained under conditions favoring the best airflow by the presence of a thick porous layer 2, and - in the absence of PCM fabric with airflow (curve D) or in the presence of PCM fabric without airflow (curve C), it is not possible to keep the temperature below 35*C. [0106] To achieve the curves A to D in figure 5, the ambient temperature was about 25*C. Comparative tests have shown that the control device according to the invention 1 allows drying 500 ml of water spread evenly over a cotton sheet as described above - 23 in about seven hours, when said mattress is covered by the body of a patient and the device 1 comprises only a second intermediate part 2, in ten hours when said second intermediate part 2 is combined with a PCM fabric 3. Tests were performed under the same conditions of ambient humidity and ambient temperature as described above. We deduce that the more rapid dehumidification with a PCM fabric 3 is probably due to reduced sweating of the patient's body. [0107] We see that, in the absence of PCM fabric 3, device 1 provides a moisture control but has limited thermal efficiency, because the measured temperature curve of the skin of a bedridden patient on the device increases with time and exceeds the critical comfort temperature of 35 0 C in the absence of PCM fabric 3. Therefore, beyond this temperature, the bedridden patient is in a dangerous state of occurrence of pressure ulcers in areas of the body at risk, such as the area of the sacrum and that of the heels for example. The PCM fabric implemented on a thick layer 2, in combination with an airflow, allows the skin temperature to remain within the comfort zone, between 28 and 35*C. [0108] This results from the fact that PCMs include a mixture of the following two PCMs: - a first PCM, whose lowest crystallization temperature is greater than 28*C, so that a portion of said microcapsules of said first PCM is in solid state at the temperature of 28*C and if the temperature in contact with the patient and the device 1 according to the invention falls below 28*C, said first PCM solidifies and releases heat, while - the second PCM has the highest melting temperature lower than 350C, namely about 33*C, so that if the temperature in contact with the patient and the device 1 rises above 35 0 C, said second PCM melts and absorbs heat. [0109] On the other hand, the comparative curves (B) and (D) in figure 5 show that the same PCM 3 fabric without the first intermediate part of polyester batting 2 (B) can still maintain the temperature of the skin under the patient below 350C provided that it is combined with an airflow. Indeed, in the absence of airflow in the presence of PCM fabric 3 but without polyester padding 2, the curve (D) exceeds 35 0 C. [0110] The phase change of the PCMs requires energy called "latent heat." We see that the combination of these two PCMs has the effect of limiting the temperature - 24 differences and tends to keep them in a narrow temperature range corresponding to a comfortable temperature. [0111] The combination of the PCM fabric 3 with an airflow (curve A) and even more so with a thick porous layer 2 (curve B), increases the effect of stabilizing the temperature below 35*C with respect to a same device without air and with PCM fabric 3 (curve C) and even more so when compared to the same device without PCM fabric 3 and with air (curve D). [0112] The presence of a PCM fabric 3 in combination with an airflow, while said airflow is promoted in the presence of a thick porous layer, helps regulate the patient's body temperature within a range of reduced temperature difference between 28 and 34.5 0 C. But, moreover, the combination of this combination [source sic] of PCM fabric 3 with an airflow and more so in combination with a thick porous layer 2, reduces even further the moisture rate in the upper layer in the vicinity of the patient, because temperature control allows avoiding, or in any case, greatly reducing the perspiration of the patient. [0113] In figure 1, the connection by welding of the lower parts 12 and upper part 11 is made through connecting strips 6. Specifically, a connecting strip 6 consisting of a fabric coated on one of its faces with a layer of polyurethane polymer and having the same properties of impermeability to air, water and water vapor [is] folded over itself to be welded to both the peripheral edge 1 a folded on itself of the top part 11 and on the peripheral edge lb of the lower part 12. (0114] The connecting strip 6 thus comprises 2 parts folded on each other, comprising since the welding 1c with the bottom part 1 2 a part forming a side flange 61 of the mattress 13 and ending with a zipper closing device 62 which opens to allow getting the mattress out of the cover 7. The side flange 61 covers the sides of the mattress 13. The other part of the strip extending from the weld 1 c with the top part 11 is a flap 63 covering said side flange 61 and the zipper closing device 62 so protected. [0115] Advantageously, said casing comprises a further opening/closing device with zipper, not shown, impermeable to air and water of the type of the devices used to -25 reversibly seal bags of food, thus permitting the opening of the casing and removing said first and second intermediate parts 2 and 3 for regular cleaning. [0116] Figures 6A, 6B, 6C show a second simplified embodiment, in which the control device 1 according to the invention acts as a protective cover of a mattress by applying directly to the underside of the second part 12 over the upper face of the mattress 13, the peripheral skirt 12-1 of the first part 12 coming to protect the vertical side edges of the mattress 13. [0117] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". [0118] Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (12)

1. Device for regulating the moisture and temperature (1) on the surface of a support element (3) of mattress or cushion type and adjacent and in contact with the body (13) of an individual lying there, comprising a casing formed by at least two parts (l1, 12) preferably connected together at their peripheral edges (1a, 1b), more preferably sealed by welding (1c), defining an interior chamber (13), said two parts consisting of a first part (11) intended to be placed on the side of said body of the individual, and a second part (12) intended to be placed on the side of said support element (3) of mattress or cushion type, said first part consisting of a material forming an impermeable barrier to air and liquid water and permeable to water vapor, said second part consisting of a material permeable to water vapor, said second part comprising at least one injection port (4) of air and means for air evacuation comprising porous or perforated areas permeable to air, preferably perforations (5), wherein said inner chamber (13) comprises capsules (4) of phase change material(s) (PCM), whose lowest crystallization temperature is above 25 0 C, preferably above 28*C and the highest melting temperature is less than 40 0 C, preferably less than 35 0 C, said capsules being integrated within and/or placed on the surface of a support, preferably a support consisting of a woven or non-woven fibrous material permeable to air (2,3).

2. Device according to claim 1, wherein said capsules are microcapsules with diameters of 10 to 500 rim, preferably 25 to 100 ptm, fixated, preferably regularly spaced, within and/or preferably on the upper surface of an air-permeable support (2,3).

3. Device according to claim 1 or 2, wherein it comprises at least two materials of the PCM type, of which a first PCM whose crystallization temperature is lower than that of the second PCM and between 250 and 30 0 C, preferably between 280 and 30 0 C and a second PCM whose melting temperature is higher than the melting temperature of the first PCM and ranging between 30* and 40 0 C, preferably between 320 and 35 0 C.

4. Device according to one of the claims 1 to 3, wherein said PCM microcapsules are applied above and/or within said support constituting an intermediate layer (2) permeable to air and water vapor, forming a fabric named 3D fabric or consisting of a fibrous non-woven very porous material, said intermediate -27 layer (2) being thicker than the first and second parts (11, 12), preferably 5 to 50 mm thick.

5. Device according to one of the claims 1 to 4, wherein it also includes an intermediate sheet (3) of fibrous nonwoven material, coated at least on its upper surface with said PCM microcapsules (4), which microcapsules have a diameter of 10 to 500 pam, preferably 25 to 100 pam, and are distributed at the rate of 10 5 to 107 microcapsules/cm 2 , preferably 106 to 5x10 6 microcapsules/cm 2 , said intermediate sheet (3) being thinner than said first and second parts (11, 12), preferably presenting a surface density of 100 to 200 g/cm 2 .

6. Device according to claims 4 and 5, wherein said interior chamber includes an intermediate sheet (3) made of thin fibrous nonwoven material (3), coated at least on its upper face with said PCM microcapsules, said intermediate sheet (3) being fixated above the upper surface of said intermediate layer (2) thicker, made of fibrous nonwoven material (3), permeable to air and to water vapor (2).

7. Device according to one of the preceding claims, wherein said PCMs are paraffinic hydrocarbons having at least one chain in C-14, of which a first PCM whose phase change temperatures are between 250 and 30 0 C, preferably the alkane, and a second PCM whose change phase temperatures are between 30* and 35*C, preferably the lycosane.

8. Device according to one of the claims 1 to 7, wherein: - the permeability to water vapor of said second part is lower than that of the first part, and - said evacuation means are said perforations (5), arranged with respect to said injection port(s) so as to be capable of creating a flow of air entering said chamber (13) by said injection port (5a) and evacuated from said chamber (13) by said evacuation means, preferably said perforations (5), throughout the volume of said chamber, when said casing is inflated by the air injected continuously pressurized through said injection port so as to create an overpressure in said chamber, and - said second part is substantially airtight between said injection port and said porous or permeable to air perforated areas, the latter being arranged far enough away from said injection port(s) so that substantially the entire volume of said chamber is - 28 crossed by the air circulating between said injection port(s) and said porous or perforated areas.

9. Device according to one of the claims 1 to 8, wherein: - said first part consists of a porous or perforated substrate, not impermeable to water and air, said substrate being coated on at least one face by a continuous polymer layer, preferably of the polyurethane type, impermeable to liquid water and air, and presenting molecular transfer properties of the water vapor, and - said second part consists of a fabric coated on at least one of its sides with a layer of polymer, preferably of the polyurethane type, having molecular transfer properties to the water vapor, preferably on the face facing the side within said chamber (13).

10. A method of regulating the temperature and moisture on the surface of a support element (3) of the mattress or cushion type and in the vicinity and in contact with the body of an individual (13) lying there, by means of a device according to one of the claims 1 to 9, wherein the following stages are performed: 1) we arrange said casing (1) flat between said support element (3) and said body of an individual (13), so that said first part (11) is turned towards the body of the individual and said second part (12) faces the side of said support element, and 2) air is injected under pressure into said chamber (13) through said injection port (5a) and at a pressure and at a rate such that said casing remains inflated in overpressure despite the evacuation of the air by said evacuation means, preferably said perforations (5) and support of the body on said casing, whereby said air pressure inside the casing relative to the outside is sufficient to permit air circulation throughout the volume of said chamber.

11. Device for regulating the moisture and temperature on the surface of a support element of mattress or cushion type and adjacent and in contact with the body of an individual lying there, said device substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.

12. A method of regulating the temperature and moisture on the surface of a support element of the mattress or cushion type and in the vicinity and in contact with - 29 the body of an individual lying there, said method substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.