Haircare appliance

Abstract

A haircare appliance 101 comprising a porous member 102 for retaining liquid and electrical circuitry configured to cause an electrical current to flow through the porous member such that liquid retai

Description

BACKGROUND Haircare appliances are generally used to treat or style hair, and some haircare appliances may treat or style hair by heating liquid. SUMMARY A first aspect of the present disclosure provides a haircare appliance comprising: a porous member for retaining liquid; and electrical circuitry configured to, when electrically connected to an electrical power supply, cause an electrical current to flow through the porous member such that liquid retained by the porous member is heated. Providing the circuitry configured to, when electrically connected to an electrical power supply, cause an electrical current to flow through the porous member such that liquid retained by the porous member is heated may cause the porous member to perform Joule heating (otherwise referred to as Ohmic heating or resistive heating) and conduct heat to liquid retained by the porous member, thus heating the liquid. The liquid may be heated to generate a vapour. This may facilitate more energy efficient and / or faster heating of liquid by the haircare appliance than, e.g., other haircare appliances wherein heat is conducted from a heating element to a porous member which retains liquid. The porous member may be for retaining water, and the electrical circuitry may be configured to, when electrically connected to the electrical power supply, cause the electrical current to flow through the porous member such that water retained by the porous member is heated to generate steam. This may facilitate the haircare appliance being usable for the treatment or styling of hair using steam. The electrical circuitry may be configured to cause the electrical current to be alternating. This may facilitate less electrolytic corrosion, gas generation, electrochemistry, electrolysis, and / or electrolytic erosion to occur at the porous member and / or liquid when the haircare appliance is in use compared to the electrical current being direct current. The electrical circuitry may be configured to cause the electrical current to be alternating with a frequency no less than one kilo Hertz (kHz). This may cause a skin depth of the electrical current through the porous member to be less than with the electrical current being direct current or alternating with a frequency less than one kHz. Thus, Joule heating due to the electrical current through the porous member when in use will occur, on average, closer to a surface of the porous member compared to with the frequency less than one kHz. Thus, facilitating improved energy efficiency of heating of the liquid retained at the surface of the porous member by the haircare appliance when in use compared to with the frequency less than one kHz. The electrical circuitry may be configured to cause the electrical current to have a root mean square voltage of no more than 20 Volts. This may avoid or reduce a need for electrical insulation between the porous member and the user. The electrical circuitry may be configured to cause the electrical current to alternate sinusoidally. This may improve the electromagnetic compatibility of the haircare appliance compared to other waveforms. A porosity of the porous member may be one of: from 10% to 80%; from 20% to 50%; from 30% to 40%; or from 40% to 50%. This may facilitate the porous member to, when in use, retain more liquid than other porous members with a lesser porosity. A density of the porous member may be no more than: 20 kilograms per metre cubed (kg-m-3); 50 kilograms per metre cubed; 100 kilograms per metre cubed; or 200 kilograms per metre cubed. This may cause a thermal mass (herein in Joules per Kelvin, J-K1) of the porous member to be less than porous members of greater density. The thermal mass being less may facilitate improved energy efficiency of heating of the liquid retained in the porous member by the haircare appliance when in use as less energy is required to increase the temperature of the porous member compared to porous members with greater thermal mass. A thickness of the porous member may be from 20 micrometres to 3 millimetres. The thickness being no more than 3 millimetres may cause the thermal mass the porous member to be less than porous members of greater thickness. The thermal mass being less may facilitate improved energy efficiency of heating of the liquid retained in the porous member by the haircare appliance when in use as less energy is required to increase the temperature of the porous member compared to porous members with greater thermal mass. The thickness being no less than 20 micrometres may simplify manufacture of the porous member compared to porous members of lesser thickness. A permeability of the porous member may be no less than: 1010 metres squared, 10'9 metres squared, 10'8 metres squared; or 10'7 metres squared. Permeability herein refers to liquid permeability. This may facilitate a greater flow rate of liquid through the porous member and thus heating of a greater volume of liquid compared to porous members with lesser permeabilities. A specific heat capacity of the porous member may be no more than: 1500 Joules per kilogram per Kelvin (J-kg-1-K-1), 1000 Joules per kilogram per Kelvin, or 500 Joules per kilogram per Kelvin. This may facilitate improved energy efficiency of heating of the liquid retained in the porous member by the haircare appliance when in use as less energy is required to increase the temperature of the porous member compared to porous members with a greater specific heat capacity. The porous member may be substantially resistant to deformation at no less than 373 Kelvin. This may facilitate the porous member to not deform with the liquid at 373 Kelvin or more. The porous member may comprise foam. This may facilitate the porous member having a desirable porosity, e.g., as described above, compared to the porous member comprising a different structure. The porous member may comprise metal foam. This may facilitate the porous member having a desirable porosity and electrical conductivity, e.g., as described above, compared to the porous member comprising a different structure and not comprising metal. The porous member may comprise stainless steel foam. This may facilitate the porous member having a desirable porosity and electrical conductivity, e.g., as described above, compared to the porous member comprising a different structure and not comprising stainless steel. The porous member may comprise electrically conductive textile. This may facilitate the porous member having a desirable porosity and electrical conductivity, e.g., as described above, compared to the porous member comprising different material. The porous member may comprise conductive micro-fibre. This may facilitate the porous member having a desirable porosity, e.g., as described above, compared to the porous member comprising a different structure. The porous member may comprise an electrical conductor. For example, the porous member may comprise at least one of: carbon fibre, carbon, copper, stainless steel, and a composite material. The porous member may comprise a woven mat comprising at least one of carbon fibre, stainless steel, or nylon. The porous member may comprise a composite of at least one of: electrically conductive fibres, electrically insulating fibres, or foam. Each of these may facilitate the porous member having a desirable electrical conductivity, e.g., as described above, compared to the porous member comprising different material. The porous member may comprise at least one of: a textile, a woven sock, a foam, a mat, a mesh, and a random mesh. This may facilitate the porous member having a desirable porosity, e.g., as described above, compared to the porous member comprising a different structure. The haircare appliance may comprise: a first electrode in electrical contact with the porous member; and a second electrode in electrical contact with the porous member, wherein the electrical circuitry is configured to supply the electrical current to the porous member by the first electrode and the second electrode. This may facilitate more efficient transfer of the electrical current from the electrical circuitry to the porous member than other arrangements. The porous member may be between the first electrode and the second electrode. This may facilitate the electrical current to flow through the porous member between the first electrode and the second electrode, e.g., causing heating of liquid retained by the porous member between the first electrode and the second electrode. The first electrode may be in contact with a first part of a surface of the porous member, and the second electrode may be in contact with a second part of the surface of the porous member, wherein the first part is different to the second part. This may facilitate the electrical current to flow along the surface of the porous member between the first part and the second part, e.g., within the skin depth from the surface, which may facilitate the heating of liquid retained by the porous member at the surface between the first part and the second part. The first electrode may comprise a first tube; the second electrode may comprise a second tube; the porous member may comprise a third tube between the first tube and the second tube; and the third tube may be in contact with an exterior surface of the first tube and an interior surface of the second tube. By utilising such tubes, at least part of the haircare appliance may be generally tubular in form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls or straights, by wrapping hair around the haircare appliance with the haircare appliance generally tubular in form. Further, this may facilitate even heating of liquid retained by the porous member. The third tube may be tapered. By utilising such a tapered tube, at least part of the haircare appliance may be generally of tapered tube form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls of a chosen diameter, by wrapping hair around the tapered tube form of the haircare appliance with the chosen diameter. An external diameter of the first tube, second tube and / or third tube may be from 8 millimetres to 80 millimetres. This may facilitate a user of the haircare appliance styling long or short hair, or allow the user to achieve a desired diameter of hair curls. The electrical circuitry may comprise: an electrical converter configured to, when connected to the electrical power supply, supply the electrical current. The electrical converter may facilitate the electrical current having desirable characteristics, such as at least one of: a voltage no more than 20 Volts, and a frequency no less than 1 kHz. The electrical power supply may be electrical mains. This may facilitate more electrical power to be supplied to the porous member and / or longer power delivery to the porous member than, e.g., a battery. The electrical power supply may comprise a battery. This may facilitate the electrical power supply to be integrated into the haircare appliance and thus facilitate use of the haircare appliance without need for other electrical power supplies, such as electrical mains. The electrical power supply may comprise a battery and electrical mains. This may facilitate more electrical power to be supplied to the porous member and / or longer power delivery than, e.g., another electrical power supply not comprising electrical mains. Further this may facilitate the battery being smaller and / or having less mass than, e.g., another electrical power supply not comprising a battery. Further, the battery may facilitate use of the haircare appliance without need for use of electrical mains. The electrical circuitry may comprise an induction coil, configured so that an induction electrical current through the induction coil induces the electrical current to flow through the porous member. This may facilitate galvanic isolation of the porous member from the electrical circuitry. The induction coil may be a helix, but other configurations of the induction coil are also envisaged. The induction coil may comprise at least one of: a plurality of coils, and a Halbach array. This may facilitate configuration of a shape of a magnetic field generated by the induction coil when the induction current flow through the induction coil, e.g., to reduce the magnetic field on a side of the induction coil. The induction coil may comprise a first helix, and the porous member may comprise a tube and / or a second helix. The tube and / or the second helix may be within the first helix. The first helix may be within the tube and / or the second helix. By utilising such a tube and helices, at least part of the haircare appliance may be generally tubular in form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls or straights, by wrapping hair around the haircare appliance with the haircare appliance generally tubular in form. Further, this may facilitate even heating of liquid retained by the porous member compared to other forms of the induction coil and / or porous member. The tube, first helix, and / or second helix may be tapered. By utilising such a tapered tube and / or helices, at least part of the haircare appliance may be generally of tapered tube form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls of a chosen diameter, by wrapping hair around the tapered tube form of the haircare appliance with the chosen diameter. A separation of the porous member from the induction coil may be from 0 millimetres to 30 millimetres. The separation being from 0 millimetres to no more than 30 millimetres may facilitate efficient induction compared to greater separations. A length of the induction coil may be from 60% to 140% of a length of the porous member. This may facilitate more efficient induction compared to greater or lesser lengths of the induction coil. An external diameter of the tube, first helix, and / or second helix may be from 15 millimetres to 45 millimetres. This may facilitate a user of the haircare appliance styling long or short hair, or allow the user to achieve a desired diameter of hair curls. The haircare appliance may comprise an electrical device configured so that the induction electrical current induces a further electrical current in the electrical device. This may facilitate the electrical device to be electrically powered by the induction coil rather than, e.g., requiring a dedicated power supply. The electrical device may be releasably attachable to a main unit of the haircare appliance. This may enable a further functionality (that of the electrical device) to be removably added to the haircare appliance. The electrical circuitry may comprise: an induction coil, configured so that an induction electrical current through the induction coil induces a receiver electrical current through a receiver coil; and a receiver converter configured to convert at least part of the receiver electrical current to the electrical current and supply the electrical current to the porous member. This may facilitate galvanic isolation of the porous member from the electrical circuitry. The induction coil may comprise a first helix; the receiver coil may comprise a second helix; and the porous member may comprise a tube and / or a third helix. The second helix may be within the first helix. The first helix may be within the second helix. By utilising such a tube and / or helices, at least part of the haircare appliance may be generally tubular in form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls or waves, by wrapping hair around the haircare appliance with the haircare appliance generally tubular in form. Further, the porous member comprising a tube and / or a third helix may facilitate even heating of liquid retained by the porous member compared to other forms. The tube, first helix, second helix, and / or third helix may be tapered. By utilising such a tapered tube and / or helices, at least part of the haircare appliance may be generally of tapered tube form. This may facilitate a user of the haircare appliance styling hair, e.g., into curls of a chosen diameter, by wrapping hair around the tapered tube form of the haircare appliance with the chosen diameter. A separation of the induction coil from the receiver coil may be from 0 millimetres to 30 millimetres. The separation being from 0 millimetres to no more than 3 millimetres may facilitate efficient induction compared to greater separations. A length of the induction coil may be from 60% to 140% of a length of the receiver coil. This may facilitate more efficient induction compared to greater or lesser lengths of the induction coil. An external diameter of the tube, first helix, second helix, and / or third helix may be from 8 millimetres to 80 millimetres. This may facilitate a user of the haircare appliance styling long or short hair, or allow the user to achieve a desired diameter of hair curls. The haircare appliance may comprise an electrical device, wherein the receiver converter is configured to convert at least part of the receiver electrical current to a further electrical current and supply the further electrical current to the electrical device. This may facilitate the electrical device to be electrically powered by the receiver converter rather than, e.g., requiring a dedicated power supply. The electrical circuitry may comprise an electrical converter configured to, when electrically connected to the electrical power supply, supply the induction electrical current to the induction coil. This may facilitate the induction electrical current to be different to an electrical current supplied by the electrical power supply, for example, a different frequency. The electrical converter may comprise a fixed-frequency resonant bus converter. This may facilitate modification of the frequency of the electrical current supplied by the electrical power supply so that the induction electrical current has a desired frequency. The haircare appliance may comprise a barrier configured to: electrically insulate a user of the haircare appliance from the electrical circuitry when the haircare appliance is in use; and inhibit water from contacting the electrical circuitry when the haircare appliance is in use. The electrical circuitry may comprise a galvanic isolator. This may reduce the risk of electrical shock of a user of the haircare appliance. The haircare appliance may comprise an insulator configured to electrically insulate a user of the haircare appliance from the porous member when the haircare appliance is in use. This may reduce the risk of electrical shock of a user of the haircare appliance. The haircare appliance may comprise a barrel, and the porous member may be within the barrel. This may facilitate a user of the haircare appliance styling hair, e.g., into curls or straights, by wrapping hair around the barrel. The porous member may comprise first perforations for air to flow through, and the barrel may comprise second perforations for air to flow through. This may facilitate the haircare appliance to emit, through the first perforations and the second perforations, an airflow when in use, e.g., allowing the haircare appliance to be used to emit the airflow for haircare. The first perforations may be at least one of: arranged substantially evenly along a length of the porous member; arranged in a plurality of substantially evenly distributed longitudinal rows along the length of the porous member; and arranged in a plurality of substantially evenly distributed circumferential rows around a circumference of the porous member. This may facilitate the haircare appliance to emit, evenly along the length and / or circumference of the porous member, through the first perforations and the second perforations, an airflow when in use. The first perforations may be at least one of: arranged substantially evenly along from 40% to 90% of a length of the porous member; arranged in a plurality of substantially evenly distributed longitudinal rows along from 40% to 90% of the length of the porous member; and arranged in a plurality of substantially evenly distributed circumferential rows around from 40% to 90% of a circumference of the porous member. This may facilitate the haircare appliance to emit, substantially evenly along from 40% to 90% of the length and / or from 40% to 90% of the circumference of the porous member, through the first perforations and the second perforations, an airflow when in use. The second perforations may be at least one of: arranged substantially evenly along a length of the barrel; arranged in a plurality of substantially evenly distributed longitudinal rows along the length of the barrel; and arranged in a plurality of substantially evenly distributed circumferential rows around a circumference of the barrel. This may facilitate the haircare appliance to emit, substantially evenly along the length of the barrel, through the first perforations and the second perforations, an airflow when in use. The second perforations may be at least one of: arranged substantially evenly along from 40% to 90% of a length of the barrel; arranged in a plurality of substantially evenly distributed longitudinal rows along from 40% to 90% of the length of the barrel; and arranged in a plurality of substantially evenly distributed circumferential rows around from 40% to 90% of a circumference of the barrel. This may facilitate the haircare appliance to emit, substantially evenly along from 40% to 90% of the length and / or from 40% to 90% of the circumference of the barrel, through the first perforations and the second perforations, an airflow when in use. The haircare appliance may comprise an airflow inlet, and an airflow generator, wherein the airflow generator is: fluidly connected to the airflow inlet, the first perforations, and the second perforations; and configured to draw an airflow in through the airflow inlet, and emit the airflow through the first perforations, and out of the second perforations. This may facilitate the haircare appliance to emit, out of the second perforations, the airflow when in use. The barrel may be tapered along the length of the barrel, from an upstream end of the barrel to a downstream end of the barrel. This may facilitate, with an airflow through the inside of the barrel and through the second perforations along a length of the barrel, a pressure within the upstream end of the barrel to be substantially equal to a pressure within the downstream end of the barrel, thus facilitating the haircare appliance to emit, evenly along the length of the barrel and through the second perforations, the airflow when in use. Further, this may facilitate a user of the haircare appliance styling hair, e.g., into curls of a chosen diameter, by wrapping hair around the tapered barrel with the chosen diameter. An external diameter of the barrel may be from 8 millimetres to 80 millimetres. This may facilitate a user of the haircare appliance styling long or short hair, or allow the user to achieve a desired diameter of hair curls. An interior of the barrel may be an airflow conduit fluidly connected to the airflow generator, the first perforations, and the second perforations. This may facilitate the airflow generator being fluidly connected to the first perforations, and the second perforations of the barrel. The haircare appliance may comprise an outlet for depositing water on the porous member. This may facilitate the generation of steam by the porous member, thus providing an additional function of the haircare appliance for haircare. The haircare appliance may comprise a plurality of outlets for depositing water on the porous member, wherein the plurality of outlets are at least one of: arranged substantially evenly along a length of the porous member; arranged in a plurality of substantially evenly distributed longitudinal rows along the length of the porous member; and arranged in a plurality of substantially evenly distributed circumferential rows around a circumference of the porous member. This may facilitate the porous member to generate steam evenly along the length of the porous member and / or the circumference of the porous member. The haircare appliance may comprise a plurality of outlets for depositing water on the porous member, wherein the plurality of outlets are at least one of: arranged substantially evenly along from 40% to 90% of a length of the porous member; arranged in a plurality of substantially evenly distributed longitudinal rows along from 40% to 90% of the length of the porous member; and arranged in a plurality of substantially evenly distributed circumferential rows around from 40% to 90% of a circumference of the porous member. This may facilitate the porous member to generate steam substantially evenly along from 40% to 90% of the length of the porous member and / or from 40% to 90% of the circumference of the porous member. The haircare appliance may comprise a main unit, and an attachment releasably attachable to the main unit, wherein the attachment comprises the porous member. This may enable the functionality of the porous member to be selectively provided to the haircare appliance, and may, for example, enable such functionality to be retrofitted to existing haircare appliances having a main unit. The attachment may comprise a first electrical connector, and the main unit may comprise a second electrical connector, wherein the first and second electrical connectors are configured to, with the attachment attached to the main unit, be electrically connected. This may facilitate the attachment being electrically connected to the main unit when attached to the main unit which, e.g., may facilitate electrical grounding of the attachment via the main unit, and / or supply of electrical power from the main unit to the attachment when the haircare appliance is in use. A second aspect of the present disclosure provides a haircare appliance attachment, wherein: the haircare appliance attachment is releasably attachable to a main unit of a haircare appliance; the haircare appliance attachment comprises a porous member for retaining liquid; and an electrical current flowing through the porous member causes liquid retained by the porous member to be heated. The haircare appliance attachment releasably attaching to the main unit may enable the functionality of the porous member to be selectively provided to the haircare appliance, and may, for example, enable such functionality to be retrofitted to existing haircare appliances having a main unit. The haircare appliance attachment may comprise: a first electrode in electrical contact with the porous member; and a second electrode in electrical contact with the porous member, wherein, with the attachment attached to the main unit, the first electrode and the second electrode are configured to receive the electrical current from electrical circuitry of the main unit, and supply the electrical current through the porous member. This may facilitate more efficient transfer of the electrical current from the electrical circuitry to the porous member than other arrangements. The haircare appliance attachment may be configured to, with the attachment attached to the main unit, have the electrical current induced in the porous member by an induction coil of the main unit. This may facilitate galvanic isolation of the porous member from the main unit. A third aspect of the present disclosure provides an appliance comprising: a porous member for retaining liquid; and electrical circuitry configured to, when electrically connected to an electrical power supply, cause an electrical current to flow through the porous member such that liquid retained by the porous member is heated. The appliance may be a thermal comfort device, a heating device, an air conditioner, a haircare appliance, and a humidifier, or a fan. The appliance may comprise a main unit, and an attachment releasably attachable to the main unit, wherein the attachment comprises the porous member. This may enable the functionality of the porous member to be selectively provided to the appliance, and may, for example, enable such functionality to be retrofitted to existing appliances having a main unit. A fourth aspect of the present disclosure provides an attachment for an appliance, wherein: the attachment is releasably attachable to a main unit of the appliance; the attachment comprises a porous member for retaining liquid; and an electrical current flowing through the porous member causes liquid retained by the porous member to be heated. The attachment releasably attaching to the main unit may enable the functionality of the porous member to be selectively provided to the appliance, and may, for example, enable such functionality to be retrofitted to existing appliances having a main unit. Optional features of aspects of the present disclosure may be equally applied to other aspects of the present disclosure, where appropriate. Brief Description of the Drawings Figure 1 schematically shows a cross-section of a haircare appliance of a first example; Figure 2 schematically shows a porous member, a first electrode, and a second electrode of the haircare appliance of Figure 1; Figure 3 schematically shows a partially exploded view of the porous member, the first electrode, and the second electrode of the haircare appliance of Figure 1; Figure 4 schematically shows a cross-section of a haircare appliance of a second example; Figure 5 schematically shows a porous member and an induction coil of the haircare appliance of Figure 4; Figure 6 schematically shows the porous member and the induction coil of the haircare appliance of Figure 4 with the porous member shown as transparent; Figure 7 schematically shows a cross-section of a haircare appliance of a third example; and Figure 8 schematically shows a porous member, an induction coil, and a receiver coil of the haircare appliance of Figure 7. Detailed Description of the Invention Figures 1 to 3 show a first example haircare appliance 101. The first example haircare appliance 101 has a main unit 130, an electrical converter 128, and an attachment 160. The main unit 130 includes airflow inlets 164, a motor drive 144, a heater drive 162, a motor 146, an impeller 156, an airflow outlet 166, and a first electrical connector 172. The main unit 130 has a generally hollow tubular housing formed of plastic. The motor drive 144, the heater drive 162, the motor 146, the impeller 156, and the first electrical connector 172 are within the tubular housing. In the first example, the airflow inlets 164 are each circular perforations of 1 millimetre in diameter in a side wall of the tubular housing of the main unit 130. The airflow inlets 164 are in evenly distributed longitudinal rows along a part of a length of the side wall and in evenly distributed circumferential rows around a circumference of the side wall. In other examples, the airflow inlets may be of other shapes and / or sizes. For example, the airflow inlets may comprise square perforations, oval perforations and / or rectangular perforations. The perforations may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. Further, in other examples the airflow inlets may not be evenly distributed along part of the length of the side wall and / or may not be evenly distributed along the circumference of the side wall. The motor drive 144 includes an inverter, is operable to control a speed of the motor 146, and is electrically connected to the motor 146. The heater drive 162 includes an inverter, is electrically connected to the first electrical connector 172, and is operable to provide an alternating electrical current to the attachment 160, as will be described in further detail hereinafter. The motor 146 is attached to the impeller 156 and is operable to rotate the impeller 156. The impeller 156 operable to generate an airflow from the airflow inlets 164 to the airflow outlet 166. The first electrical connector 172 is releasably connected to a second electrical connector 170 of the attachment 160 and is operable to provide an electrical connection between the main unit 130 and the attachment 160. The first electrical connector 172 is electrically connected to the heater drive 162. The airflow outlet 166 is defined by circular perforations of 2 millimetres in diameter. The circular perforations are at an end of the tubular housing of the main unit 130. In other examples, the airflow outlet may be defined by perforations having other shapes and / or sizes. For example, the airflow outlet may defined by square perforations, oval perforations, and / or rectangular perforations. In further examples, the perforations may be no more than 1 millimetre in diameter, be no more than 0.5 millimetres in diameter, and / or be no more than 0.2 millimetres in diameter. The main unit 130 is electrically connected to the electrical converter 128 by a first electrical cable 138. The first electrical cable 138 delivers electrical power to the motor drive 144 and the heater drive 162. The first electrical cable 138 is not shielded; in other examples the first electrical cable is shielded. The electrical converter 128 includes an inverter 132, a first rectifier 133, a transformer 134, a second rectifier 136, and has a body made of plastic. The inverter 132, the transformer 134, the first rectifier 133 and the second rectifier 136 are within the body of the electrical converter 128. A second electrical cable 158 is electrically connected to the electrical converter 128 and to electrical mains. The first rectifier 133 is electrically connected to the second electrical cable 158 and the inverter 132. The inverter 132 is electrically and the transformer 134. The transformer 134 is electrically connected to the inverter 132 and the second rectifier 136. The second rectifier 136 is electrically connected to the main unit 130 by the first electrical cable 138. The second electrical cable 158 is shielded; in other examples the second electrical cable is not shielded. It will be appreciated that the inverter 132, the transformer 134, the first rectifier 133, and the second rectifier 136 can be considered to be electrical circuitry in the context described herein. The transformer 134 acts to galvanically isolate the main body 130 of the haircare appliance 101 from electrical mains. The attachment 160 includes a first electrode 108, a second electrode 110, a porous member 102, airflow outlets 168, and the second electrical connector 170. The attachment 160 has aplastic housing that defines a first hollow barrel. The attachment 160 is releasably attached to the main unit 130 by corresponding magnetic connectors (not shown for sake of clarity). The first electrode 108, the second electrode 110, the porous member 102, and the second electrical connector 170 are within the plastic housing. In other examples, the housing may not be made of plastic, but another electrically insulating material. The first electrode 108 is a first tube with a circular cross-section, an external diameter of 30 millimetres, and a thickness of 2 millimetres. In other examples, the external diameter may be from 8 millimetres to 80 millimetres and / or the thickness may be from 20 micrometres to 3 millimetres. The first electrode 108 is made of gold and is electrically conductive. In other examples, the first electrode may be made of any other electrically conductive material; for example, copper, indium tin oxide, or carbon. The first electrode 108 has perforations 114 that are in substantially evenly distributed longitudinal rows along a length of the first electrode 108 and in substantially evenly distributed circumferential rows around a circumference of the first electrode 108. In other examples, the perforations of the first electrode may have other shapes and / or sizes. For example, the perforations may be square perforations, oval perforations, and / or rectangular perforations. In further examples, the perforations may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. Further, in other examples, the perforations of the first electrode may not be evenly distributed along the length of the first electrode and / or may not be evenly distributed along the circumference of the first electrode. The second electrode 110 is a second tube with an external diameter of 35 millimetres and a thickness of 2 millimetres. In other examples, the external diameter may be from 8 millimetres to 80 millimetres and / or the thickness may be from 20 micrometres to 3 millimetres. The second electrode 110 is made of gold and is electrically conductive. In other examples, the second electrode may be made of any other electrically conductive material, for example, copper, indium tin oxide, or carbon. The second electrode 110 has perforations 116 that are in substantially evenly distributed longitudinal rows along a length of the second electrode 110 and in substantially evenly distributed circumferential rows around a circumference of the second electrode 110. In other examples, the perforations of the second electrode may have other shapes and / or sizes. For example, the perforations may be square perforations, oval perforations, and / or rectangular perforations. In further examples, the perforations may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. Further, in other examples, the perforations of the second electrode may not be evenly distributed along the length of the second electrode and / or may not be evenly distributed along the circumference of the second electrode. The porous member 102 is a third tube with an external diameter of 33 millimetres and a thickness of 3 millimetres. In other examples, the external diameter may be from 8 millimetres to 80 millimetres. The porous member 102 has perforations 112 in substantially evenly distributed longitudinal rows along a length of the porous member 102 and in substantially evenly distributed circumferential rows around a circumference of the porous member 102. The perforations 112 are each circular and 3 millimetres in diameter. In other examples, the perforations of the porous member may have other shapes and / or sizes. For example, the perforations may be square perforations, oval perforations, and / or rectangular perforations. In further examples, the perforations may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. Further, in other examples, perforations of the porous member may not be in evenly distributed longitudinal rows along the length of the porous member and / or may not be in evenly distributed circumferential rows around the circumference of the porous member. The porous member 102 is configured to retain a liquid which is applied to it. In this example, the liquid is water, but in other examples, other liquids may be applied. The porous member 102 is stainless steel foam with a porosity of 50%; a density of 50 kilograms per metre cubed, permeability of 10'8 metres squared, a specific heat capacity of 1000 Joules per kilogram per Kelvin; a mass of 0.01 kilograms, a thermal mass of 10 Joules per Kelvin, an electrical conductivity at 293 Kelvin of 1000000 Siemens per metre, and an electrical resistivity at 293 Kelvin of 0.000001 Ohm metres. The porous member 102 is between the first electrode 108 and the second electrode 110. The porous member is resistant to deformation at 373 Kelvin. In other examples, the porous member may comprise any other electrically conductive material(s). For example, the porous member may comprise at least one of: electrically conductive textile, electrically conductive micro-fibre, carbon fibre, carbon, copper, stainless steel, a composite material. The airflow outlets 168 comprise circular perforations of 2 millimetres in diameter in a side wall of the housing of the attachment 160. In other examples, the airflow outlets may comprise perforations having other shapes and / or sizes. For example, the airflow outlets may be square perforations, oval perforations, rectangular perforations. In further examples, the perforations may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. The airflow outlets 168 are in substantially evenly distributed longitudinal rows along a part of a length of the side wall of the housing of the attachment 160 and in substantially evenly distributed circumferential rows around a circumference of the side wall of the housing of the attachment 160. In other examples, the airflow outlets may not be in evenly distributed longitudinal rows along the part of the length of the side wall and / or may not be in evenly distributed circumferential rows around the circumference of the side wall. The second electrical connector 170 is releasably connected to the first electrical connector 172 of the main unit 130 and is operable to provide the electrical connection between the main unit 130 and the attachment 160. The second electrical connector 170 is electrically connected to the first electrode 108 and the second electrode 110. When the attachment is fully assembled, an exterior surface of the first electrode 108 is in contact with an interior surface of the porous member 102 and is in electrical contact with the porous member 102. The perforations 114 of the first electrode 108 are aligned with the perforations 112 of porous member 102. The second electrode 110 is in contact with an exterior surface of the porous member 102 and is in electrical contact with the porous member 102. The perforations 116 of the second electrode 110 are aligned with the perforations 112 of porous member 102. With the haircare appliance 101 in use, the attachment 160 is attached to the main unit 130 such that the first 172 and second 170 electrical connectors are electrically connected to one another. The pores of the porous member 102 retain water applied to the porous member 102. The water may be applied to the porous member 102 by a user of the haircare appliance 101, through the airflow outlets 168. Electrical power is supplied to the electrical converter 128 from electrical mains via the second electrical cable 158. The first rectifier 133, the inverter 132, the transformer 134, and the second rectifier 136, within the electrical converter 128 then convert the supplied electrical power, which is AC by virtue of being delivered from the electrical mains, into DC electrical power having a voltage of 30 Volts. The DC electrical power is supplied to both the heater drive 162 and the motor drive 144. The inverter of the heater drive 162 converts the DC electrical power into AC electrical power that has a sinusoidal form and a frequency of 60 kHz. In other examples, the frequency may be no less than 1 kHz. The AC electrical power is supplied to the porous member 102 via the second electrical connector 170, the first electrical connector 172, the first electrode 108, and the second electrode 110. This causes an alternating electrical current to flow through and between the first electrode 108, the porous member 102, and the second electrode 110. The alternating electrical current flowing through the porous member 102 causes the porous member 102 to increase in temperature due to Joule heating. Heat is then transferred from the porous member 102 to the water retained in the pores of the porous member 102, thus heating the water and generating steam. The generated steam is then emitted from the haircare appliance 101 through the airflow outlets 168. The user of the haircare appliance 101 can then use the generated steam for haircare and / or hairstyling, for example with the user wrapping their hair around the barrel defined by the housing of the attachment 160. Heating the porous member 102 which retains liquid may facilitate more energy efficient and / or faster heating of the liquid by the first example haircare appliance 101 than, e.g., other haircare appliances wherein heat is conducted from a heating element to a porous member retaining liquid. The motor drive 144 takes the DC electrical power received from the electrical converter 128, and, via the inverter motor drive 144, drives the motor 146, thus rotating the impeller 156, and thus generating an airflow. The airflow is drawn into the main unit 130 through the airflow inlets 164. The airflow then flows through the main unit 130 and through the airflow outlet 166 into the attachment 160. The airflow then flows through the attachment 160 and out of the airflow outlets 168. The airflow flows from the interior of the first electrode 108, through the perforations 114 of the first electrode 108, the perforations 114 of the porous member 102, and the perforations 116 of the second electrode 110, and out of the airflow outlets 268. In other examples, the teachings of the first example can be equally applied to a haircare appliance having the main unit and the attachment integrally formed together as a single unit. Some such examples do not include the first electrical connector and the second electrical connector, the heater drive is electrically connected to the first electrode and the second electrode. In other examples, the teachings of the first example can be equally applied to a haircare appliance having the main unit and the electrical converter integrally formed together as a single unit. Although the first example is described as having a motor, an impeller, and a motor drive, it will be appreciated that the teachings of the first example can be equally applied to a haircare appliance not having any of these features. A second example haircare appliance 201 is now described with reference to Figures 4 to 6. The second example haircare appliance 201 has an attachment 260 and a main unit 230. The main unit 230 includes airflow inlets 264, a motor drive 244, electrical circuitry 280, a motor 246, an impeller 256, an airflow outlet 266, and a first electrical connector 272. The main unit 230 has a generally hollow tubular housing formed of plastic. The motor drive 244, the electrical circuitry 262, the motor 246, the impeller 256, and the first electrical connector 272 are within the tubular housing. The airflow inlets 264 are each circular perforations in a side wall of the tubular housing of the main unit 230. The airflow inlets 264 are in substantially evenly distributed longitudinal rows along a part of a length of the side wall of the tubular housing of the main unit 230 and in substantially evenly distributed circumferential rows around a circumference of the side wall of the tubular housing of the main unit 230. The motor drive 244 includes a rectifier and an inverter. The motor drive 244 is operable to control a speed of the motor 246 and is electrically connected to the motor 246. The electrical circuitry 280 includes a rectifier, an inverter, and a transformer. The electrical circuitry 280 is electrically connected to the first electrical connector 272 and is operable to provide an alternating electrical current to the attachment 260, as will be described in further detail hereinafter. The transformer is operable to galvanically isolate the electrical mains from the attachment 260. The motor 246 is attached to the impeller 256 and is operable to rotate the impeller 256. The impeller 256 is operable to generate an airflow from the airflow inlets 264 to the airflow outlet 266. The first electrical connector 272 is releasably connected to a second electrical connector 270 of the attachment 260 and is operable to provide an electrical connection between the main unit 230 and the attachment 260. The first electrical connector 272 is electrically connected to the electrical circuitry 280. The airflow outlet 266 is defined by circular perforations. The circular perforations are at an end of the tubular housing of the main unit 230. The main unit 230 is electrically connected to electrical mains by an electrical cable 258. The electrical cable 258 delivers electrical power to the motor drive 244 and the electrical circuitry 280. The attachment 260 includes an induction coil 218, a porous member 202, airflow outlets 268, and the second electrical connector 270. The attachment 260 has a plastic housing that defines a first hollow barrel. The attachment 260 is releasably attached to the main unit 230 by corresponding magnetic connectors (not shown for sake of clarity). The porous member 202, the induction coil 218, and the first electrical connector 270 are within the plastic housing. The porous member 202 is a woven layer of electrically conductive textile and is tubular with a circular cross-section. The induction coil 218 is a copper helix. Other configurations of the induction coil are envisaged, in other examples, the induction coil may comprise at least one of: a plurality of coils, and a Halbach array. Further, in other examples, the induction coil may be made of other materials, such as brass, nickel, steel, and / or aluminium. A length of the induction coil 218 is the same as a length of the porous member 202. The induction coil 218 is within the porous member 202. A first end of the copper helix and a second end of the copper helix are each separately electrically connected to the heater drive (via the first electrical connector 272 and the second electrical connector 270). The induction coil 218 is operable to induce an electrical current through the porous member 202 with an induction electrical current flowing through the induction coil 218. The airflow outlets 268 are each circular perforations in a side wall of the housing of the attachment 260. The airflow outlets 268 are in evenly distributed longitudinal rows along a part of a length of the side wall of the housing of the attachment 260 and in evenly distributed circumferential rows around a circumference of the side wall of the housing of the attachment 260. The second electrical connector 270 is releasably connected to the first electrical connector 272 of the main unit 230 and is operable to provide the electrical connection between the main unit 230 and the attachment 260. The second electrical connector 270 is electrically connected to the first end of the copper helix and the second end of the copper helix. With the haircare appliance 201 in use, the attachment 260 is attached to the main unit 230 such that the first 272 and second 270 electrical connectors are electrically connected to one another. The pores of the porous member 202 retain water applied to the porous member 202 by a user of the haircare appliance 201 through the airflow outlets 268. Electrical power is supplied to the main unit 230 from electrical mains via the electrical cable 258. The electrical power is supplied to both the electrical circuitry 280 and the heater drive 244. The electrical circuitry 280 then converts the electrical power, which is AC by virtue of having come from the electrical mains, to AC electrical power with a root mean square Voltage value of approximately 2 Volts and a frequency of 100 kHz. In other examples, the root mean square Voltage value may be 2 Volts, 15 Volts, no more than 15 Volts, no more than 10 Volts, or no more than 4 Volts. Further, in other examples the frequency may be no less than 1 kHz. The AC electrical power is supplied to the induction coil 218 via the second electrical connector 270 and the first electrical connector 272. The AC electrical power through the induction coil 218 induces an alternating electrical current to flow through the porous member 202. The alternating electrical current flowing through the porous member 202 causes the porous member 202 to increase in temperature due to Joule heating. Heat is then transferred from the porous member 202 to the water retained in the pores of the porous member 202, thus heating the water and generating steam. The generated steam is then emitted from the haircare appliance 201 through the airflow outlets 268. The user of the haircare appliance 201 can then use the generated steam for haircare and / or hairstyling. In a similar manner to the first example haircare appliance 101, the second example haircare appliance 201 facilitates direct heating of the porous member 202. Furthermore, by using the induction coil 218, galvanic isolation of the porous member 202 from the mains power supply may be achieved without needing to use a transformer. The motor drive 244 takes the electrical power received from the electrical mains and, via the rectifier and the inverter that each form part of the motor drive 244, drives the motor 246, thus rotating the impeller, and thus generating an airflow. The airflow is drawn into the main unit 230 through the airflow inlets 264. The airflow then flows through the main unit 230 and through the airflow outlet 266 into the attachment 260. The airflow then flows through the attachment 260 and out of the airflow outlets 268. Other electrical and / or airflow configurations are envisaged. In other examples, the teachings of the second examples can be equally applied to a haircare appliance having the main unit and the attachment integrally formed together as a single unit. Such examples may not include the magnetic connectors, the first electrical connector, and the second electrical connector; further, the electrical circuitry is electrically connected to the induction coil. A third example haircare appliance 301 is now described with reference to Figures 7 and 8. The third example haircare appliance 301 has a main unit 330, a porous member 302, an induction coil 318, a receiver coil 319, a water tank 322, a motor drive 344, a motor 346, an impeller 356, airflow inlets 364, airflow outlets 368, and electrical circuitry 380. The main unit 330 includes the porous member 302, the induction coil 318, the receiver coil 319, the water tank 322, the motor drive 344, the motor 346, the impeller 356, the airflow inlets 364, the airflow outlets 368, and the electrical circuitry 380. The main unit 330 has a generally hollow tubular housing formed of plastic. The porous member 302, the induction coil 318, the receiver coil 319, the water tank 322, the motor drive 344, the motor 346, the impeller 356, and the electrical circuitry 380 are within the tubular housing. The porous member 302 is an electrically-conductive micro-fibre and is tubular with a circular cross-section. In other examples, the porous member is made of at least one of microfibre, foam, mesh, and composite structures. In other examples, the porous member may have other cross-sections, e.g., oval. The induction coil 318 is a first copper helix. In other examples, the induction coil may comprise at least one of: a plurality of coils, and a Halbach array. Further, in other examples, the induction coil may be made of other materials, such as: brass, nickel, steel, and / or aluminium. A length of the induction coil 318 is greater than a length of the porous member 302. The first part of the induction coil 318 is within the porous member 302 and a second part of the induction coil 318 is within the receiver coil 319. A first end of the first copper helix and a second end of the first copper helix are each separately electrically connected to the electrical circuitry 280. The induction coil 318 is operable to induce a first electrical current through the porous member 302 and a second electrical current through the receiver coil 319. The receiver coil 319 is a second copper helix. A length of the receiver coil 219 is less than the length of the induction coil 318. A first end and a second end of the second copper helix are each separately electrically connected to the motor drive 344. The water tank 322 includes a plastic container, a water pump in the plastic container, and three outlets. The three outlets are circular apertures in a side of the water tank 322 and each have a diameter of 2 millimetres. The water tank 322 is operable to deposit water stored in the plastic container on the porous member through the three outlets. In other examples, the water tank may have greater than three or fewer than three apertures in the side of the water tank. In other examples, each of the apertures may have other shapes and / or sizes. For example, the apertures may be square apertures, oval apertures, and / or rectangular apertures. In other examples, the apertures may be no more than 1 millimetre in diameter, no more than 0.5 millimetres in diameter, and / or no more than 0.2 millimetres in diameter. The motor drive 344 includes a rectifier and an inverter. The motor drive 344 is operable to control a speed of the motor 346 and is electrically connected to the motor 346. The motor 346 is attached to the impeller 356 and is operable to rotate the impeller 356. In other examples, the impeller may be built into the motor. The impeller 356 is operable to generate an airflow from the airflow inlets 364 to the airflow outlet 366. The airflow inlets 364 are each circular perforations of in a side wall of the tubular housing of the main unit 330. The airflow inlets 364 are in evenly distributed longitudinal rows along a first part of a length of the side wall of the tubular housing of the main unit 330 and in evenly distributed circumferential rows around a circumference of the side wall of the tubular housing of the main unit 330. The airflow outlets 368 are each circular perforations in the side wall of the tubular housing of the main unit 330. The airflow outlets 368 are in evenly distributed longitudinal rows along a second part of a length of the side wall of the tubular housing of the main unit 330 and in evenly distributed circumferential rows around a circumference of the side wall of the tubular housing of the main unit 330. The electrical circuitry 380 includes a rectifier and an inverter. The electrical circuitry 380 is electrically connected to the induction coil 318 and is operable to provide an alternating electrical current to the induction coil, as will be described in further detail hereinafter. The main unit 330 is electrically connected to electrical mains by an electrical cable 358. The electrical cable 358 delivers electrical power to the motor drive 344 and the electrical circuitry 380. With the haircare appliance 301 in use and with the plastic container containing water, the water pump pumps the water from the plastic container out of the outlets of the water tank 322 thus depositing the water on the porous member 302. The water is retained within pores of the porous member 302. The volume of water retained within the pores of the porous member is, for example, 1 millilitre or no more than 1 millilitre. Electrical power is supplied to the main unit 330 from electrical mains via the electrical cable 358. The electrical power is supplied to the electrical circuitry 380. The electrical circuitry 380 then converts the electrical power, which is AC by virtue of having come from the electrical mains, to AC electrical power with a Voltage value of 5 Volts. In other examples, the Voltage value is approximately 5 Volts. The AC electrical power is supplied to the induction coil 318. The AC electrical power through the induction coil 318 induces a first alternating electrical current to flow through the porous member 302 and a second alternating electrical current to flow through the receiver coil 319. The first alternating electrical current flowing through the porous member 302 causes the porous member 302 to increase in temperature due to Joule heating. Heat is then conducted from the porous member 302 to the water retained in the pores of the porous member 302, thus heating the water and generating steam. The generated steam is then emitted from the haircare appliance 301 through the airflow outlets 368. The user of the haircare appliance 301 can then use the generated steam for haircare and / or hairstyling. The receiver coil 319 takes the second electrical current and supplies it to the motor drive 344. The motor drive 344 takes the second electrical current received from the receiver coil 319, and, via the rectifier and the inverter that both form part of the motor drive 344, and drives the motor 346, thus rotating the impeller 356, and thus generating an airflow. The airflow is drawn into the main unit 330 through the airflow inlets 364. The airflow then flows through the main unit 330 and out of the airflow outlets 368. It will also be appreciated that in some examples, the haircare appliance has a barrier within a housing of the main unit. The barrier is a layer of electrical insulator and, e.g., encapsulates the heater drive, the motor, and the motor drive. The barrier electrically isolates the motor drive the motor, and the heater drive from the user of the haircare appliance, the liquid, and the gas. Further, it will also be appreciated that in some examples, the haircare appliance includes a receiver coil electrically connected to the porous member. With the haircare appliance of such examples in use, the AC electrical power through the induction coil induces an AC electrical current to flow through the receiver coil. The alternating electrical current flowing through the receiver coil is supplied to the porous member and causes the porous member to increase in temperature due to Joule heating. In some such examples the receiver coil and the induction coil galvanically isolate the main unit from the electrical mains. In each of the examples described above, a porous member is heated, and this may facilitate more energy efficient and / or faster heating of liquid by the haircare appliance than, e.g., other haircare appliances wherein heat is conducted from a heating element to a porous member retaining liquid. It will be appreciated that parameters of the porous member, such as the porosity and thickness, may vary in practice. It will also be appreciated that in other examples, the electrical current flowing through the porous member when the haircare appliance is in use may have different parameters. In some examples, the electrical current flowing through the porous member has at least one of a frequency greater than 1 kHz, and a Voltage of no more than 20 Volts. In other examples, a size, for example a diameter, of a barrel of the haircare appliance and / or attachment may be varied. Further, in other examples, a shape of the barrel may be varied, e.g., elliptical, four-leaf clover, and / or three sub-barrels. It will further be appreciated that a location of various electrical components, whether in the main body of the haircare appliance, or in a separate housing located proximal to a plug of the haircare appliance, may be varied as desired. Furthermore, embodiments in which a battery is utilised as a power source, instead of mains power, are also envisaged. Although examples are described that utilise attachments, it will be appreciated that the teachings of such examples can be equally applied to main units that define integrally formed barrels. Equally, it will be appreciated that the teachings of examples that utilise main units with integrally formed barrels can be used in examples that utilise attachments. Although examples are described as having a motor, an impeller, and a motor drive, it will be appreciated that the teachings of such examples can be equally applied to a haircare appliance not having any of these features. Although examples are described as having means for applying liquid and / or water to the porous member, it will be appreciated that other means for applying liquid and / or water to the porous member are envisaged, e.g., by capillary action. Whilst examples and embodiments have thus far been described, these are illustrative only and various modifications may be made without departing from the scope of the invention as defined by the claims.

Claims

1. A haircare appliance comprising:a porous member for retaining liquid; andelectrical circuitry configured to, when electrically connected to an electrical power supply, cause an electrical current to flow through the porous member such that liquid retained by the porous member is heated.

2. The haircare appliance of claim 1, wherein the porous member is for retaining water, and the electrical circuitry is configured to, when electrically connected to the electrical power supply, cause the electrical current to flow through the porous member such that water retained by the porous member is heated to generate steam.

3. The haircare appliance of claim 1 or claim 2, wherein the electrical circuitry is configured to cause the electrical current to at least one of:be alternating;be alternating with a frequency no less than one kilo Hertz; and have a root mean square voltage of no more than 15 Volts RMS.

4. The haircare appliance of any preceding claim, wherein the porous member comprises at least one of: metal foam, stainless steel foam, composite material, and electrically conductive textile.

5. The haircare appliance of any preceding claim, comprising:a first electrode in electrical contact with the porous member; and a second electrode in electrical contact with the porous member, wherein the electrical circuitry is configured to supply the electrical current to flow through the porous member by the first electrode and the second electrode.

6. The haircare appliance of claim 5, wherein:the first electrode comprises a first tube;the second electrode comprises a second tube;the porous member comprises a third tube between the first tube and the second tube; andthe third tube is in contact with an exterior surface of the first tube and an interior surface of the second tube.

7. The haircare appliance of any of claims 1 to 4, wherein the electrical circuitry comprisesan induction coil, configured so that an induction electrical current through the induction coil induces the electrical current.

8. The haircare appliance of claim 7, comprising an electrical device configured so that the induction electrical current induces a further electrical current in the electrical device.

9. The haircare appliance of any of claims 1 to 6, wherein the electrical circuitry comprises:an induction coil, configured so that an induction electrical current through the induction coil induces a receiver electrical current through a receiver coil; anda receiver converter configured to convert at least part of the receiver electrical current to the electrical current and supply the electrical current to the porous member.

10. The haircare appliance of claim 9, comprising an electrical device, wherein the receiver converter is configured to convert at least part of the receiver electrical current to a further electrical current and supply the further electrical current to the electrical device.

11. The haircare appliance of any preceding claim, comprising a barrier configured to: electrically insulate a user of the haircare appliance from the electrical circuitry when the haircare appliance is in use; andinhibit liquid from contacting the electrical circuitry when the haircare appliance is in use.

12. The haircare appliance of any preceding claim, wherein the electrical circuitry comprises a galvanic isolator.

13. The haircare appliance of any preceding claim, comprising an insulator configured to electrically insulate a user of the haircare appliance from the porous member when the haircare appliance is in use.

14. The haircare appliance of any preceding claim, comprising a barrel, wherein the porous member is within the barrel.

15. The haircare appliance of claim 14, wherein the porous member comprises first perforations for air to flow through, and the barrel comprises second perforations for air to flow through.

16. The haircare appliance of claim 15, wherein the first perforations are at least one of: arranged in a plurality of substantially evenly distributed longitudinal rows along a length of the porous member; andarranged in a plurality of substantially evenly distributed circumferential rows around a circumference of the porous member.

17. The haircare appliance of claim 15 or claim 16, wherein the second perforations are at least one of:arranged in a plurality of substantially evenly distributed longitudinal rows along a length of the barrel; andarranged in a plurality of substantially evenly distributed circumferential rows around a circumference of the barrel.

18. The haircare appliance of any of claims 15 to 17, comprising an airflow inlet, and an airflow generator, wherein the airflow generator is:fluidly connected to the airflow inlet, the first perforations, and the second perforations; andconfigured to draw an airflow in through the airflow inlet, and emit the airflow through the first perforations, and out of the second perforations.

19. The haircare appliance of any of claims 14 to 18, wherein the barrel is tapered along the length of the barrel from an upstream end of the barrel to a downstream end of the barrel.

20. The haircare appliance of any preceding claim, comprising a main unit, and an attachment releasably attachable to the main unit, wherein the attachment comprises the porous member.

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