Water pipe

Abstract

An electric water pipe system comprises a water pipe device 2 and a base 110, wherein the device 2 is releasably mountable upon the base in use 110. The water pipe device 2 comprises: a heating chambe

Description

The present disclosure relates to a water pipe, particularly, but not limited to, an electronically controlled and / or electrically heated hookah-type device. Background of the invention A prior art hookah device is shown in WO 2015 / 172224. The device comprises an electronically heated chamber at an upper end thereof configured to receive a capsule comprising a smoking product. The user of the device inhales through a hose and draws air into the capsule. The air entrains a smoking product, which passes through a conduit into water tank provided at the lower end of the device. The smoking products passes through water into the tank, and through the hose to the user. The device thus acts in some ways akin to a conventional shisha pipe, although heating of the smoking product is electronically controlled instead of relying on conventional charcoal heating. Electrically-heated hookahs are particularly well suited to heating applications where it is not intended to burn the consumable product, but instead heat it to a controlled elevated temperature for emitting vapour to a user. As such devices of this kind can be used to deliver a variety of less harmful or therapeutic substances to the user than conventional hookahs. Another example of an electronic hookah device is disclosed in WO 2017 / 080545. The different configuration of the device in that example has the heating chamber at the bottom of the device and the water tank on top, with an electronics compartment having batteries therebetween. The hose extends from the top of the device so that when a user draws on the hose, air is drawn upwards from the heating chamber through the water tank. This arrangement is beneficial for a compact, e.g. portable, device but the positioning of the water tank atop the device means that the sealing of the device against water penetration is more onerous. A limited number of other examples of electronic hookah devices exist in the prior art. However this is a relatively new type of product and the majority of hookah devices in use still rely on charcoal / combustion-based heating. A common feature of electronic hookah devices in the prior art is that they have been developed to be simpler for the end user to achieve a reliable experience without having to prepare a hookah bowl themselves. As such, electronic hookah devices to-date have focussed mainly on the end user who may use the device at home or in a portable manner. There has been little focus on the development of electronic hookah devices for a bar or cafe environment. As such existing devices accommodate a single user or single session well but are less suited to use in a busy, public environment in which devices may be repeatedly used by one or a group of users at one time, or which may need to accommodate different users with different tastes / requirements in quick succession. In view of the above, there are practical challenges in designing an electrically-heated, capsule-based hookah so that it offers a convenient experience for adoption in multi-user environments. The present invention aims to overcome or ameliorate one or more of the above problems. Statement of Invention According to a first aspect, there is provided an electric water pipe system comprising a water pipe device having: a heating chamber arranged to receive a consumable product, the heating chamber having an air inlet and an electric heater for heating the consumable product; a liquid reservoir arranged to contain a coolant and having an air outlet leading to a mouthpiece; a gas pathway passing from the heating chamber into the liquid reservoir whereby a user can draw air in use through the water pipe device by suction using the mouthpiece; and, the water pipe system further comprising, a base for the water pipe whereby the water pipe is releasably mountable upon the base in use, the base comprising an electrical energy store and an electrical connector for powering the water pipe device when mounted upon the base. The electrical energy store typically comprises one or more battery. The electric energy store may be rechargeable. The electrical energy store may have a capacity / charge sufficient to power the water pipe device, e.g. the electric heater thereof, for in excess of 30 minutes, one hour, two hours, three hours, four hours, five hours or more. The water pipe system may comprise capsules of consumable material arranged to be received by the heating chamber. The capsule may comprise a pre-filled or pre-packed single use capsule, e.g. containing a predefined quantity of consumable product which may be suitable for a single usage session. The capsules of consumable material may have defined session duration for consumption of the consumable material. The session duration may be at least 30 minutes, 45 minutes, 60 minutes, 75 minutes or 90 minutes. The electric energy store may have a capacity sufficient to power the electric water pipe in use (i.e. to maintain an in-use temperature of the heating chamber) for a duration that is greater than the defined session time. At full charge, the energy store may be capable of powering the electric water pipe to heat the heating chamber for at least 1.5, 2, 3, 4, 5, 6, 7 or 8 times the session duration. The water pipe device may be mounted / seated upon the base, e.g. such that the weight of the water pipe device is borne / supported by the base. The water pipe may be loosely seated upon the base. The water pipe device may lift off the base without resistance or unlocking. The liquid reservoir of the water pipe device may be received by the base and / or may rest upon the base. The water pipe device may lift off the base when removed therefrom. The base may be shaped to receive the water pipe device or liquid reservoir. The base may have a concave or recessed upper surface to receive the device / reservoir. The base and reservoir may be correspondingly shaped. The base and / or water pipe device, e.g. the liquid reservoir, may have an alignment feature such as a male / female alignment feature. The base may comprise a projection and the device or reservoir may comprise a recess, or vice versa. The alignment feature may be central on the base, e.g. in the upper surface thereof. The water pipe device may be arranged such that the heating chamber is above the liquid reservoir. The gas pathway may pass though an internal void or compartment between the liquid reservoir and heating chamber. The compartment may define an internal void around the gas pathway. This may allow heat dissipation from the gas pathway, e.g. to help the gas pathway cool the gases at elevated temperature passing through it. The gas pathway may comprise a conduit or pipe, e.g. a down pipe. The system may be arranged such that the liquid reservoir sits upon the base and the heating chamber is spaced from the base by the liquid reservoir. In height order from top to bottom, the system may comprise the heating chamber, the liquid reservoir and the base. The base and water pipe device may be axially aligned, e.g. relative to a vertical or central axis of the system. The heating chamber and liquid reservoir may be axially aligned The base may comprise a housing or enclosure for the electrical energy store. The housing or enclosure for the electrical anergy store may be watertight or moisture impervious. The electrical energy store may be disposed within an internal cavity of the base. The base may comprise channels, e.g. in an upper surface or side wall thereof, for water management of accidental spills. The base may be rotatable. The base may comprise a lower / member and an upper member, wherein the upper member is rotatable relative to the lower member. The upper member may carry the electrical connector and / or electrical energy store. The base may comprise one or more wheel or bearing. The base, or a member thereof, may rotate about a substantially vertical axis upon the wheel / bearing. A plurality of wheels or bearing members may be disposed, e.g. angularly spaced, about a central / vertical axis. The base may comprise one or more indicator or interface. A status indicator may be provided. The indicator may take the form of one or more light. The indicator may be arranged as an array of lights. The indicator may extend along a rim or edge of the base. The indicator may extend in an annular direction around the base, e.g. around a recess arranged to receive the water pipe device or around a peripheral rim of the device. A battery or electrical charge status indicator may be provided on the base. A power status indicator may be provided, e.g. power delivery to the water pipe device. An active heating or temperature status indicator may be provided. A duration status indicator may be provided, e.g. to indicate a duration of use of the water pipe device or base, such as a session duration. The base may comprise one or more light arranged to shine into the liquid reservoir, or other transparent portion, of the water pipe device. The one or more light may comprise any of the optional features of the indicator defined above. Accordingly the light may be an indicator light and / or an illumination device for other purposes. The electrical connector may be provided on an upstanding and / or flexible arm of the base. The arm may extend upwardly and / or outwardly form the base. The electrical connector may be provided on the arm. The arm may extend upwardly from the base to bypass the liquid reservoir and connect to a connector on the water pipe device. The water pipe device and base may be in communication when in use. The electrical connector may comprise a data connection. There may be provided a controller on the water pipe device for controlling the electric heater. There may be a controller on the base for controlling a user interface / indicator and / or controlling power delivery to the water pipe device. The controller of the device may be in communication with the controller of the base or vice versa. A security handshake may be performed, e.g. such that the water pipe device will only be operative with a verified base or vice versa. Additionally or alternatively, the base may check one or more electrical parameter of a connection with a water pipe device and selectively supply power to the device based upon said check. The water pipe device may be devoid of an electrical energy store. The water pipe device may be inoperative when disconnected form the base. The heating chamber may be for heating and / or vaporising the consumable product in use. The device may comprise a closure. The closure may selectively close the heating chamber. The inlet may be provided on the closure. The closure may seal the heating chamber when closed, save for the inlet. A compartment may be provided between the heating chamber and the fluid container, e.g. an internal compartment of the housing. The compartment may be provided in a narrowing or neck region of the device, e.g. which may be narrower than the liquid reservoir and / or heating chamber portion. A further inlet or port may provide fluid communication between the compartment and the exterior (e.g. including the liquid reservoir) or the ambient environment. The inlet may comprise a grating, mesh or grille. The compartment may form a neck portion and / or electronics compartment of the housing. The conduit may extend through the compartment. A conduit may be provided between the heating chamber and fluid container. The conduit may comprise a tube or pipe. Air from the second inlet may be directed to provide cooling of one or more internal component. Air from the second inlet may directed over the conduit to provide cooling thereof. Air from the second inlet may directed into the conduit. The conduit may be arranged, with other components to aid the dissipation of heat from the vapour in the conduit. A wider conduit portion or widening in the air pathway may be provided. The widening may be adjacent / proximal the constriction. A tapered or stepped transition may be provided between the widening and the constriction or vice versa. According to a further aspect, there is provided the water pipe device of the first aspect having an electrical connector arranged for connection with the base, e.g. such that the water pipe device is devoid of an on-board power source and / or is only operable when mounted to the base. According to a further aspect, there is provided the base of the first aspect arranged to receive the water pipe device and power the device when mounted on the base. According to a further aspect, there is provided a method of using water pipe systems comprising: providing a plurality of water pipe devices each having: a heating chamber arranged to receive a consumable product, the heating chamber having an air inlet and an electric heater for heating the consumable product; a liquid reservoir arranged to contain a coolant and having an air outlet leading to a mouthpiece; a gas pathway passing from the heating chamber into the liquid reservoir whereby a user can draw air in use through the water pipe device by suction using the mouthpiece; providing a plurality of bases for the water pipe devices, each base comprising an electrical energy store and an electrical connector for powering the water pipe device when mounted upon the base; providing a consumable product in one water pipe device for a user and mounting said water pipe device to a base for use by the user. The water pipe device may be prepared for use separately from the base. The water pipe device may be simply removed / disconnected from the base at the end of a session. The water pipe device may be swapped and / or re-prepared for further use at the end of a session. Any optional or preferable features described in relation to any one aspect of the invention may be applied to any further aspect, wherever practicable. Detailed Description Practicable embodiments of the disclosure are described below in further detail, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a perspective view of a water pipe device; Figure 2 shows a side view of the water pipe device; Figure 3 shows a sectional side view of the water pipe device; Figure 4 shows a perspective view of a conduit of the water pipe device; Figure 5 shows a sectional view a transition portion on the conduit; Figure 6 shows a perspective view of a mouthpiece of the water pipe device; Figure 7 shows a perspective cross-sectional view of the mouthpiece; Figure 8 shows a perspective view of a tank lid assembly of the water pipe device; Figure 9 shows a sectional view of the tank lid assembly; Figure 10 shows a perspective view of a purge valve assembly; Figure 11 shows a sectional side view of a first air cooling system; Figure 12 shows a three-dimensional view of a base for the water pipe device; Figure 13 shows a three-dimensional view of the water pipe system with the water pipe device mounted on the base; Figure 14 shows an exploded view of the base. A water pipe device 2 is shown in figures 1 and 2. In general, the device 2 is configured to heat a consumable smoking or vapour-producing product to allow inhalation thereof by a user. The consumable product may comprise any suitable form as described in the art. The consumable product may comprise a tobacco-based product, for example, shisha. The water pipe device could thus be used as a hookah or shisha pipe. However a wide variety of consumable products are possible, including alternatives to tobacco and / or therapeutic products for delivery of vapour to the user. The consumable product is provided in a capsule 3. The capsule 3 is configured to be heated by the device 2. The capsule 3 comprises a pre-filled and sealed / closed capsule of consumable material. Accordingly multiple capsules 3 of differing types can be provided to offer the user alternative consumable materials in a prepacked or ‘pod’ format. A user can thus select the desired type of capsule for consumption and it can simply be placed / loaded into the device for use as will be described below. In the context of a bar or cafe, a menu of capsule types may thus be provided, from which consumers can select. The different types of capsule may comprise different ingredients (e.g. different flavours), different formulations (e.g. active ingredients, such as stimulants or relaxants). The capsules 3 may be prefilled and closed / sealed in a manner that has bee described in the prior art. Each capsule 3 typically has perforations 5, which allow air flow to / from the capsule when in use. The perforations may be covered / sealed during manufacture to retain the freshness of the capsule and then exposed for use at the appropriate time, e.g. by peeling a cover away from the perforations or using another mechanism. In other examples, the capsule could be perforated at the point of use, e.g. forming the perforations only at the point they are needed for use. The consumable product may comprise a tobacco-based product. The consumable product may comprise non-tobacco product. The consumable product may comprise cannabis, tea or other plant-based or synthetic material intended to bring about a desirable sensation or therapeutic effect for the user when vapour given off by the heated product is inhaled. The device 2 is portable but is typically used as a tabletop device. The device comprises a head portion 4. The head portion 4 is configured to contain the smoking product capsule in use. The device 2 typically receives the capsule on or within the head portion 4. The head portion 4 is provided at the upper end of the device in use. The head portion 4 comprises a disc or lenticular / convex shape, e.g. being wider than a neck portion of the device. The device 2 comprises a base portion 6. The base portion provides a reservoir, container or tank for a cooling liquid 8 (e.g. water). The base portion 6 is generally bulbous or rounded. The base portion 6 comprises a flat lower surface 10 to ensure the device 2 stays upright. The lower surface 10 may comprise grip members (e.g. rubber pads). The base portion 6 comprises a transparent material. This allows the user to ensure the water level is correct. The base 6 may comprise glass. The base 6 may comprise a transparent polymer, for example, one or more of: acrylic (PMMA); butyrate; polycarbonate; PET; or PETG. A neck portion 12 defines a housing / compartment region that connects the base 6 and the head 4 portions. The neck portion 12 tapers toward the head portion 4. The base portion 6 and neck portion 12 may comprise a pear or tear shape. The head portion 4 is wider than the neck 12 at the interface therebetween. The head portion 4 thus extends outwardly from the neck portion. The head portion 4 thus provides a flange or rim. The neck portion 12 provides a handle for the user. The head portion 4 and the neck portion 12 may be opaque. The neck portion 4 may comprise a grip or the like and could comprise a high-friction material (e.g. rubber etc) if desired. The neck portion 12 contains a compartment 12A (shown in figure 3), which will be described in detail later. The head portion 4 and neck 12 are detachable / separable from the base portion 6. The housed compartment 12A is therefore separable from the base 6. This allows access to the reservoir to add / remove cooling liquid therefrom. The neck portion 12 may be removably attached to the base 6 by a threaded connection, a bayonet connection, or similar connection means. The device 2 is generally circular in cross-section (i.e. in a top-down direction). However, it can be appreciated, the device may comprise any suitable cross-sectional shape, e.g. polygonal, elliptical or complex shape. The cross-sectional shape may vary along the axial length of the device 2. The device 2 comprises a thermally and / or electrically insulating material on its exterior, i.e. defining a housing for the internal components / structures. Typically the device 2 housing comprises a polymeric material. A hose 14 is connected to the device 2. The hose 14 is removably attached. This allows the hose 14 to be cleaned and / or detached for storage. The hose 14 is received with an aperture or socket 16 (shown in figure 2) in the neck portion 12. The hose 14 is therefore fluidly connected to the interior of the base 6, i.e. to the air space in the interior of the water tank. The hose 14 is mounted via an interference or friction fit. A hose connector 18 and / or the aperture / socket 16 may comprise a high-friction material (e.g. rubber). One or more seal may be provided at the interface between the hose end connector 18 and the aperture / socket 16. The connector 18 is tapered toward an end thereof. In other embodiments, the hose may be mounted to the device 2 via one or more of: a fastener; a latch; a screw thread; an indent / detent arrangement; a clamp or other suitable means. A releasable hose is provided in the embodiment shown but a permanently mounted hose could be used if desired. The hose 14 is flexible. The hose 14 may comprise a flexible polymer. The hose 14 comprises a mouthpiece 20. The mouthpiece 20 may be removable / detachable from the hose 14. The mouthpiece 20 may comprise a removable cover / mouth or the like (e.g. to improve hygiene between multiple users). The head 4 comprises a lid 22 to provide an opening thereto. This allows insertion of the capsule 3 containing the consumable product. The lid 22 is pivotably / hingedly attached to the device 2. The lid 22 is provided at the upper end of the device 2. The smoking product is therefore loaded into the upper end of the device in this example. The lid 22 comprises a round / circular shape. As shown in figure 3, a heater 24 is mounted within the device 2. The heater 24 is mounted within the electronics compartment 12 and / or head portion 4. The heater 24 is mounted about a chamber 26 configured to receive the capsule 3. The heater 24 heats the capsule, e.g. through the chamber wall, to vaporise or otherwise disperse one or more ingredient of consumable product in use. The walls of the heater 24 and / or chamber 26 are shaped to conform to the shape of the capsule 3, e.g. being tapered. The capsule thus forms a close fit with the heater in use. The chamber 26 comprises a concave shape. Typically, the chamber 26 is trapezoidal or frustoconical. The heater 24 encloses or surrounds the capsule in use. The lid 22 closes the heating chamber 26. The cavity / chamber is thus sealed / enclosed in use in the form of an oven. One or more heating element may be provided on, within and / or integral with the walls of the heating chamber 26. The heating chamber 26 comprises a thermally conductive material (e.g. metal). Typically, the heating means comprise a resistive element (i.e. heated by electrical current flowing therethrough). The resistive element may be formed directly on or be integral with the walls of the heating chamber. However, any suitable means may be used to heat the heating chamber 26 and / or capsule 3, for example, one or more of: inductive heating; microwave heating; infrared heating; convective heating (e.g. the heating element is spaced from the heating chamber wall); electronically controlled combustion heating (e.g. using gas or other fuel). As best seen in figure 1, the lid 22 comprises an air inlet 28 therein. The heating chamber 26 therefore comprises one or more air inlet 28 to allow air into the heating chamber 26. This air then mixes with the vaporised product in the heating chamber 26. The air inlet 28 allows air to pass through the lid 22 (i.e. the inlet 28 provides a channel through the lid 22). The air inlet 28 is provided in a central portion of the lid 22. The air inlet 28 is thus provided over the heating chamber 24 / capsule in use. The air inlet 28 may comprise a plurality of apertures or perforations. The air inlet 28 may comprise a grille or mesh to prevent debris entering the inlet 28. The heater 24 may be controlled by electronics (not shown) in the electronics compartment 12 (e.g. via a heater controller). The electronics may comprise a microcontroller / microprocessor; memory (volatile and / or non-volatile); and / or electrical regulation circuitry (e.g. power limiter and / or controller). The electronics compartment 12 comprises any suitable components to provide heating of the heater 24. The device 2 may comprise a communication interface. The communication interface may be wired and / or wireless. The wire interface may comprise a USB or Ethernet interface (e.g. USB port). The wireless interface may comprise an interface for communication via one or more of: Wi-Fi; Bluetooth; NFC; Infrared; cellular (e.g. GSM, 3G, 4G, 5G etc.). The device 2 may comprise any suitable antenna for wireless communication. A power switch 30 may be provided on the front / side of the device 2. The device 2 and / or the heater 24 may therefore be manually controlled (e.g. activated / deactivated). The switch may comprise a push switch or touch interface. However this feature is optional since an alternative arrangement may comprise a switch on a base device (to be described below). In such an arrangement, the power switch 30 may be replaced with an electrical connection to a base device. The device 2 comprise an optional indicator 32. The indicator comprises a light (e.g. an LED). The indicator 32 may indicate a power level to the heater 24 and / or the temperature thereof. The indicator 32 comprise a series of lights. Thus, the number of lights illuminated may be indicative of the power level / temperature of the heater 24. In some embodiments, the indicator 32 may comprise a display or the like. The display may be interactive (e.g. a touchscreen). The heating chamber 24 is operatively / fluidly connected to the water / cooling tank 6 via a conduit 34. The conduit 34 provides a pipe, tube or channel from the heating chamber interior to a coolant / water contained in the tank. The conduit 34 is generally sealed to / against the heating chamber 24 to prevent air leakage therefrom. The conduit 34 extends into the tank 6 to a depth proximal the base of the tank. The conduit 34 therefore extends into the cooling fluid within the tank in use. The conduit may comprise a one-way valve to prevent back flow into the heating chamber 24. The conduit 34 passes through the electronics compartment 12A in the neck 12. The conduit 34 therefore seals or segregates the heating chamber 24 and / or vapourised product from electronic compartment 12A to prevent contamination thereof. The electronics compartment comprises a cavity or hollow to accommodate the conduit 34. The cavity is fluidly isolated from the heating chamber 24 and / or the water container 6. The conduit 34 comprises a diffuser 36. The diffuser 36 is typically provided at an end 38 of the conduit 34. The diffuser may comprise a plurality of apertures, which in this example take the form of slots or cut-outs in the side wall of the conduit 34 The end 38 of the conduit 34 may be closed / sealed (i.e. such that all air pass through the diffuser). Alternatively, the end 38 of the conduit 34 may be open, in which case gas / vapour may exit the conduit through the end opening and the apertures in the side wall thereof. The end 38 may be narrowed or otherwise constricted in some examples. In use, air passes into the air inlet 28 and into the heating chamber 24. The air then entrains vaporised smoking product in the heating chamber 24. The air then passes into the conduit 34 and through the water / coolant in the tank 8. The air and / or vapour is cooled and / or filtered in the coolant. The air then bubbles up through the coolant and into the hose 20. Typically, air flow is provided by a negative pressure from the user (i.e. applied at the mouthpiece 20). Where a capsule is used, porous walls are provided on capsule to allow air to enter the capsule and / or to allow the vaporised product to escape therefrom. Porosity may be provided by apertures or perforations on one or more sides of the capsule. The apertures are typically less than 5mm in diameter. The conduit 34 is shown in isolation in figures 4 and 5. The conduit 34 comprises a first portion 34A. The first portion 34A is contained within the neck portion 12, i.e. passing through compartment 12A. The conduit 34 comprises a second portion 34B. The second portion 34B extends into the tank 6 and / or the cooling liquid when present. The second portion 34B therefore protrudes / depends from the housing of the neck portion and / or compartment 12A to its distal end 38. The portions 34A,B are fluidly connected via a connector assembly or mounting 40. The connector assembly 40 provides an airtight connection therebetween. A support structure 42 is configured to engage and support the conduit 34 and is described herein as a chassis since it provides common support for a number of components and / or sub-assemblies. The chassis 42 is configured to support the conduit 34 and / or electronics, batteries 35 etc within the neck portion 12 (see figures 8 and 9). This prevents any undesired lateral and / or vertical movement of the conduit 34 relative to other internal components or the housing. Referring back to figure 5, the chassis 42 comprises an aperture to receive the first conduit 34A. The aperture comprises a collar or sleeve 44 configured to surround the conduit 34A. The sleeve 44 forms a tight fit with the conduit 34A. The sleeve 44 comprises a gasket, screw thread 46 or other releasable sealing means. A flange 48 or rim is provided at the end of the sleeve 44. The flange 48 limits movement of the conduit 34A (i.e. provides a stop member). The chassis 42 and the first conduit 34A are received within a cavity 50, i.e. end opening, in the second conduit 34B. The chassis 42 is thus interposed between the first and second conduits 34A,B. This helps to secure both conduit portions. The second conduit 34B comprise a rim of flange 52. The flange 52 comprises a gasket or seal 54 configured to abut / seal against the chassis 42. The gasket / seal 54 is annular. Typically, the sleeve 44 is fully received within the cavity 50 such that the second conduit 34B abuts the chassis 42. The cavity 50 in the second conduit 34B decreases in cross-sectional area with distance away from the first conduit 34B. The cavity 50 thus comprises tapering internal side wall 56. The cavity 50 comprises a conical or funnel shape. The tapering / conical shape provides a constriction or narrowing. The cavity 50 comprise a greater cross-section area or width than the first conduit 34A at the interface therebetween. The cavity 50 thus provides a widening. A second cavity 58 is provided adjacent the tapering sides wall 56. The second cavity 58 comprise a reduced cross-sectional area relative to the first cavity 50 and the first conduit 34A. A third cavity 60 is provided adjacent the second cavity 58. The third cavity 60 comprises a reduced cross-sectional area relative to the second cavity 58 and the first conduit 34A. The second conduit 34B thus comprise a reduced effective cross-sectional area (i.e. inner diameter) than the first conduit 34A in the region beyond the first cavity 50. In the present embodiment, the transition between the second cavity 58 and the third cavity 60 is discontinuous. This provides a step 62 or like between the cavities 58,60. The increased width cavity 50; tapering walls 56 and / or the step 62 induce turbulent, vortical or otherwise nonlinear flow (see arrows in figure 5). The reduction in diameter of the conduit also accelerates the flow along the second conduit 34B relative to the first conduit 34A. In the present embodiment, the widening / constriction arrangement is provided at an end of second conduit 34B. This allows easy machining of the tapering / step structure. In some embodiments, the widening / constriction may be provided part way along the second conduit 34B (i.e. toward the end 38 of the conduit 34). In some embodiments, widening / constriction arrangement is provided on the first conduit 34A. The arrangement may be provided at an end or part way along the first conduit 34A. In some embodiments, the transition between the cavities 50,58,60 comprises a respective step arrangement. In some embodiments, the transition between the cavities 50,58,60 comprises a tapering arrangement. In some embodiment, a single transition may be provided (e.g. a single tapering or step). In some embodiments, a plurality of cavities may be provided, with a respective step / tapering transition provided therebetween. In the current example, the second conduit 34B has increased wall thickness compared to the first conduit 34A. The second conduit 34B thus has a greater mass of material making up the conduit at low temperature, i.e. cooled by the water in the tank 6. The acceleration and triggering of turbulence in the gas / vapour flow through the second conduit portion relative to the first conduit, as well as the diffuser arrangement as the gas / vapour enters the water has been found to provide both a good draw resistance for the user and concentration of vapor derived from the constricted flow rate through the heating chamber. The mouthpiece 20 shown in closer detail in figures 6 and 7. The mouthpiece 20 comprises mouth portion 64 configured to be receive on / within the user’s mouth. The mouth portion 64 may be shaped to accommodate the user’s lip(s). The mouthpiece 20 comprises a handle portion 66. The mouthpiece 20 is generally elongate (e.g. comprises a cylindrical shape) and extends upstream of the mouthpiece 64, e.g. adjacent the air inlet 68 such that the user can operate the air inlet whilst gripping the handle. The mouthpiece comprises an air inlet 68 to allow air from the ambient environment to enter the mouthpiece. The ambient air then mixes with the gas / vapour passing through the mouthpiece from the hookah pipe 2. This helps to increase airflow to the user and / or may provide cooling to the airflow. The effective cross-section of the air inlet 68 is variable to allow variation of the airflow into the mouthpiece from the inlet 68. This allows the user to selectively vary the total airflow through the mouthpiece. The air inlet 68 is provided in a collar / sleeve 70. The collar 70 is rotatable relative to the mouthpiece 20. The collar 70 is movable such that an inlet 68 is aligned with an aperture 72. The aperture 72 is formed with a conduit or channel 74 enclosing an internal cavity 76 in the mouthpiece. The e 70 thus movable such that an inlet 68 is fluidly connected to the cavity 76 provided within the mouthpiece. A plurality of inlets 68A,B,C are provided. Each of inlets 68A,B,C comprise different cross-sectional areas (e.g. diameters). Thus, the by rotating the collar 70, the user can align the desired inlet 68A,B,C over the internal aperture 72. Given the different cross-sectional areas of the inlets 68A,B,C, the effective inlet flowrate can be varied by the user, i.e. the rate at which ambient air is entrained into the flow to the mouthpiece when a user draws. Although three inlets 68A,B,C are provided in the present embodiment, it can be appreciated that as many inlets 68 can be provided as required, thus allowing finer / coarser adjustment of the inlet flowrate as required. The collar 70 may be rotatable such that none of the inlets 68 are aligned with the aperture 72 (i.e. to a “closed” position). The internal inlet 72 has a greater cross-sectional area than the inlets 68A.B.C, ensuring that the inlets 68A,B,C are limiting factor in the flowrate. The inner channel 74 and the collar 70 may be spaced by a spacer 78. The spacer 78 provides a sleeve or the like surrounding the channel 74. The spacer 78 comprises a cavity / aperture 80 to allow fluid communication between the aperture 72 and the inlet 68. The spacer 78 may comprise a low friction material to aid rotation of the sleeve 70. Indicia may be provided to indicate the position of the collar 70. The indicia may indicate the position of the aperture 72 and / or which inlet 68 is aligned therewith. The indicia may indicate a flowrate. The indicated flowrate may be arbitrary (e.g. “high”, “medium”, “low”). It can be appreciated that a similar arrangement can be provided by forming a plurality of different sized apertures 72 on the inner conduit 74. The sleeve 70 could comprise a single aperture 68 movable into position over the different sized apertures 72. In some embodiments, substantially the same function may be provided by a sliding arrangement. For example, a plurality of inlets 68 are provided on linearly movable carriage or slider. The slider is movable to align the desired inlet 68 with the inner aperture 72. The slider may be axially movable along the mouthpiece 20. In some embodiments, the size of the inlet 68 or the inner aperture 72 may be elongate and / or continuously variable. For example, the inlet 68 / aperture 72 may comprises a wedge or tapering shape. The sleeve / slider is therefore movable to allow continuous variation of the effective size of the aperture, i.e. to reveal a greater or smaller portion of the aperture to vary its effective flow area. In some embodiments, the inlet / valve may not be adjustable, thus allowing a fixed airflow therethrough. For example, a simple aperture or channel may be provided in the mouthpiece. The user may selectively vary the airflow therethrough by obscuring the inlet / valve with their finger, or a slider etc. Referring to figures 8-10, the device 2 may comprise a second air inlet arrangement 82, e.g. to allow ambient air to enter the water tank 6. The ambient air then mixes with the air within the tank 6 from the heating chamber 24. This helps to increase airflow to the user and / or may provide cooling to the airflow. The inlet 82 is provided within a lid arrangement 84. The lid 84 is configured to substantially seal the air tank 6. The lid 84 is formed integrally with the neck chassis 40. The lid 84 comprises a skirt 86. The skirt 86 is configured to surround an upstanding flange or lip 88 on the tank 6. The skirt 86 and flange 88 are releasably attached. This allows the user to empty / fill the tank 6. The skirt 86 and flange 88 are releasably attached via cooperating screw thread. However, it can be appreciated that any suitable mechanism may be used, for example, a bayonet arrangement, interference fit, latches, friction fit etc. The skirt 86 and / or lid 84 is configured to seal against the flange 88 to ensure water-tight connection therebetween. A purge valve assembly 90 is provided to allow purging of the air within the tank 6. For example, this may allow the user to remove stale air from the tank 6 in the direction of arrow A. The purge valve 90 comprise a diaphragm or cap 92. The diaphragm 92 is configured to abut against a seat 94. The diaphragm 92 may biased into engagement with the seat 94 (see figure 10) to ensure an effective seal therebetween. The bias may be provided by the resiliency of the valve. The valve seat 94 may form a plug or the like configured to received with the lid 84. In other embodiments, the valve assembly 90 may be integral with the lid 84. The valve assembly 90 provides unidirectional airflow. Air can therefore egress the tank via the valve 90, however, ingress is prevented when a user applies a negative pressure to the tank via the mouthpiece. The valve assembly 90 may comprise any suitable arrangement check valve, for example: a ball valve; swing valve; lift valve; duckbill; reed; or stop valve. The user ma purge the tank by applying positive pressure to the mouthpiece, i.e. by blowing instead of drawing. In use, when air pressure is increased within the tank 6, the diaphragm 92 is lifted or deforms away from the valve seat 94. The valve 92 therefore moves to an open position and air can egress the tank 6. Air then passes out through an outlet 96 provided in the housing of the neck portion 12. The outlet 96 comprises a grating or mesh to prevent contamination within the housing 12. In some embodiments the outlet 96 comprises a filter or the like. One or more secondary air inlet 98 is provided in the purge valve assembly 90. The inlet 98 allows air to ingress the tank 9. In the present embodiment, the air inlet 98 comprises a channel or aperture. The channel 98 is unobscured / open (i.e. no valve or the like is provided). The secondary air inlet 98 is therefore passive. The air inlet 98 is provided in the valve seat 94. A plurality of apertures are provided. The shape, number and / or size of the apertures is generally configured to prevent excessive flow of air therethrough. Instead, the secondary air inlet 98 is provided to reduce the resistance to airflow through the device when drawing at the mouthpiece. Also, in the interest of prolonging the duration over which a single capsule is consumed, it is desirable that a relatively low flow rate through the capsule is maintained. As such the constriction in the conduit and the tight seal with the capsule are beneficial features for capsule longevity and consistent smoking but produce an abnormally high resistance to draw, or low flow rate, experienced by the user. The consistent flow through the secondary air inlet 98 and / or user controlled inlet 68 allow for an improved experience by the user. In use, the user draws air through the mouthpiece, reducing the instantaneous pressure within the tank. As shown in figure 9, this draws air through the conduit 34 and the inlet 98 into the tank 6. Both the conduit air and the inlet air mix in the tank, and then pass into the hose 14. In some embodiments, airflow through the inlet 98 may be adjustable. An adjustment mechanism may be provided as described in relation to inlet 68. In some embodiments, the air flowing to the inlet 98 may be used to provide cooling for the device 2. Air may enter via the device via a second inlet 100. The air may then be direct around one or more components of the device 2 to provide cooling thereof. As shown in figure 11, the cooling air 102 may be directed over or onto the conduit 34. The device may comprise a secondary inlet 100 fluidly communicating with the conduit. The primary inlet 98 is provided in lid 90 the tank 6, as previously described. The second inlet 100 may be provided on the neck portion 12 or adjacent the head portion 4. The cooling air 102 may therefore flow along / around a length of the conduit 34. The cooling air 102 may help to cool the conduit 34. The neck / electronics compartment 12 may comprise a substantially open structure (i.e. provides a cavity). The cooling air 102 is therefore free to move within the compartment 12, thereby cooling any components therein. In other embodiments, a secondary inlet 100 is not provided and the air in the chamber 12A may be generally still / trapped e.g. in the form of a closed housing with a void or cavity therein. The cavity may be hermetically sealed to prevent any moisture ingress. In some embodiments, the conduit 34 comprises a heat sink and / or heat exchanger. The heat sink / exchanger may comprise any suitable form. The heat sink / exchanger may comprise fins or baffles. Referring back to Figure 3, a thermal break 106 is operatively provided between the heating chamber 24 (i.e. the outlet thereof 108) and the conduit 34. The thermal break prevents or limits heat transfer between the heating chamber 24 and the conduit 34. This may help to prevent the conduit 34 becoming excessively hot and / or the heating chamber 24 losing excessive thermal energy. This helps to thermally isolate the heating chamber 24 from the remainder of the device 2. The thermal break also helps ensure a significant temperature gradient between the heating chamber 24 and the conduit 34 so that the conduit can cool the gases / vapour passing therethrough in use. The thermal break 106 is provided at an end of the conduit adjacent the heating chamber 24. The thermal break 106 is thus provided at the interface between the heating chamber 24 and the conduit 34. Substantially the full length of the conduit 34 is therefore thermally isolated from the heating chamber 24. The thermal break 106 physically separates the conduit 34 and heating chamber 24, such that they form completely separate, divisible / discrete portions, whilst remaining in fluid communication. A portion of the conduit 34 and heating chamber 24 are received within the thermal break 106. The thermal break 106 thus surround a portion of the conduit 34 and the heating chamber 24 accordingly. The thermal break 106 is annular / cylindrical. The thermal break 106 may therefore provide a sleeve, pipe, tube or channel. In some embodiments, the thermal break 106 may comprise a relatively small axial length. The thermal break 106 may comprise a ring or the like. The thermal break 106 comprises a low thermal conductivity (i.e. thermally insulating) material. The material may comprise a polymer. The material may comprise heat resilient silicones or the like. The material may comprise an elastomer (e.g. rubber). The material may comprise a ceramic. The above-described water pipe device 2 is devoid of an on-board power source, e.g. a battery or the like. In some embodiments, the water pipe device 2 could have a small onboard energy store that is insufficient to power the device for a single usage session, e.g. of 30 mins or 60 mins. A small on board battery could be provided that is sufficient for only a few minutes e.g. 10 minutes, 5 mins or less, of power to the heater 24, e.g. to provide warning that operation of the device will shortly stop. Thus the device requires a power source to be provided for normal use of the water pipe device 2 as will be described below in relation to figures 12-14. In some examples, the water pipe device may have an auxiliary energy store onboard, e.g. in the form of one or more battery, which is of lower capacity than the primary energy source of the base. The auxiliary energy store, is used, may be less than a quarter or fifth of the energy store of the base. The power source for the water pipe device 2 is provided by way of a base 110, in this example provided as a free-standing base unit. The base provides a free standing power source that can power the water pipe device for multiple sessions, e.g. for an active usage duration of in excess of 300 minutes or 400 minutes. The current base arrangement is capable of powering the water pipe device for around 500 minutes when fully charged. This means it can be reliably charged ready for a full day of operation before recharging is required. The base energy store may provide at least 100Wh, 150Wh or 200Wh. The energy store in the base may comprise an array of cells, e.g. six, ten or twelve cells or more. 20700 or 21700 cells may be used for example. In the current example a 12x 21700, 216Wh configuration has been used. The base 110 comprises a housing 112 defining an enclosure in which electric / electronic components of the base can be provided. The base 110 is widest at its bottom surface and tapers towards an upper surface 114. The base / housing are bulbous in form, e.g. being round or circular in plan. The shape of the base approximates a hemisphere except that the upper portion thereof is truncated / recessed to receive the water pipe device 2. The base 110 has an upper rim 116 defining the perimeter of the recessed upper surface 114. The recessed upper surface is concave, e.g. in the form akin to a dish or bowl. In this example, the upper surface has a tapered side wall portion and a flat central portion. As such it corresponds to the shape of the lower portion of the liquid reservoir, e.g. as can be seen in figure 2 and 11. The bottom of the water pipe device 2 thus sits snugly within the upper surface 114 of the base 110 for use. As best seen in figure 3, the bottom of the water pipe device (i.e. the underside of the liquid reservoir 6) has a central recess or indentation 118. The upper surface 114 of the base as shown in figure 13 has a central protrusion 120, which corresponds with the underside of the water pipe device 2. This ensures the correct seating of the device 2 on the base 110, i.e. with the protrusion 120 located in the recess 118. The base comprises a first electrical connector 122 which is provided in the form of an upstanding arm. The connector 122 extends upwardly from the base from a location outside the rim 116. The connector arm is flexible or semi rigid such that it can be manipulated into the desired angular orientation above the upper surface 114. The connector 122 comprises a port 124 or male connector formation at its distal end. The upper surface 114 and side wall of the base 110 may be water proof, e.g. providing a water-tight enclosure for the components therein. Alternatively, the base housing may be splash proof or protected against a certain level of water ingress. The base 110 has a further electrical connector 126 spaced from the first connector 122, e.g. beneath it and / or towards the bottom of the base. The connector 126 may be used for charging the base for example. A power button 128 is also provided, e.g. on a common panel with the electrical connector 126. The base has illumination means. In this example a lighting ring / annulus 130 is provided adjacent the rim 116. The lighting ring 130 is slightly inside the rim 116 in this example. As series of lights, e.g. LED’s, extend around the lighting annuls. These can be used for ambient lighting, lighting of the reservoir 6 or device 2, and / or to provide one or more status indication to a user or operator. The illumination means are selectively or variably operable to provide feedback to a viewer, e.g. about the status of one or more operational parameters for the device. The lighting ring 130 in this example can be incrementally illuminated, e.g. in increments around the perimeter of the upper surface 114. As such, the extent of illumination around the annulus can convey information to a viewer. The extent of illumination in this example can be used to indicate the state of charge of the base. Additionally or alternatively, it could be used to indicate the remaining time, or elapsed time, of a usage session of the device. One or more further operational parameter could be indicated using illumination means, such as the temperature of the water pipe device heating chamber 26 and / or one or more other status, such as a fault, a lid open / closed status or an electrical connection status between the device 2 and base 110. In addition to, or instead of, the incremental lighting of the lighting ring 130, the illumination means may be illuminated in a plurality of colours or transient lighting patterns, e.g. flashing ripple effect, or similar. In some embodiments, a portion or colour of the lighting ring 130 may be used to provide feedback on one parameter or function, whereas another colour or portion of the ring 130 may be used to provide feedback on another parameter or function. Thus the illumination means provides a versatile but simple feedback system whilst also allowing for aesthetic lighting of the water pipe when in use. The lighting ring is arranged to align with the lower portion of the transparent reservoir 6 of the water pipe device 2 so that it can illuminate the reservoir and the liquid therein, e.g. as bubbles pass through the water during active use. The base may be described as a plinth or pedestal upon which the water pipe device sits as shown in figure 13. The base thus supports the weight of the water pipe device 2 when assembled for use. The base and water pipe device are commonly designed to be axially alignable about a central axis. The base may be rotatable as will be described below, i,e, such that the base can swivel with the water pipe thereon about the central axis, e.g. to make it easy for a user to access the mouthpiece, regardless of there orientation relative to the device 2. It can be seen that the electrical connector extends to the side of the reservoir 60 of the water pipe 2 when seated on the base. The connector 122 is of sufficient length to extend to the electronics compartment 12 of the device 2. The connector thus spans the height of the reservoir 6 or extends around the reservoir in order to provide an electrical connection to the electronics compartment. The connector 122 may be generally flat against the reservoir 6 when connected to the device. The connector 122 may be flat or belt-like in form. The device / compartment 12 is provided with a corresponding electrical connector formation 132, e.g. on its exterior. The connectors 122 and 132 may form a plug and socket type arrangement. A male connector formation may be inserted into a female connector formation. The connection once formed may be water impervious or water tight, e.g. to prevent ingress of water from the reservoir 6. A seal formation may be provided around the connecting formations. The connector 132 is hooded / enclosed as shown, e.g. such that the exposed connector formation is downward facing. A bespoke connector arrangement may be provided. The device as shown in figure 13 omits the hose 14 (see figure 1) but is otherwise ready for use with electrical power form the base being provided to the water pipe 2 when connected. Thus the heater of the water pipe draws power from the base in use. The system described above is particularly beneficial for water pipe devices that are intended to undergo heavy or varying use (e.g. between different users with different tastes). For example in a bar or cafe environment, a series of devices 2 and / or bases 110 can be kept. When a water pipe is ordered, the desired capsule 3 can be inserted in the device 2, which can them be presented to the user / customer on the base and connected up for use. Once a session has ended the water pipe can be simply removed and replaced with a different device on the base for further use e.g. by the same or a different customer / user. As such varying devices can be provided / changed simply and quickly to meet varying user requirement. The base has an onboard energy store that is sufficient for more than a single smoking session / capsule. The energy store is sufficient to power a plurality of usage sessions, e.g. the duration of which may be specified according to the capsule that has been inserted for consumption or else which may be manually set before the session starts. Thus is particularly useful for multi user sessions whereby the duration of the session is not limited by the device 2 but rather has a much greater capacity for extended use. The base may power two, three, four or more consecutive usage sessions before it requires recharging. As such the capacity of the energy store is significantly greater than could practically be provided on-board the device 2 without making it awkwardly cumbersome or heavy. The capsule may carry information about the duration of the usage session that is appropriate to consume the contents. This may be provided as a code on the capsule that can be read by the device 2 or an operator. As such the session duration can be set automatically by the device or manually by someone setting up the water pipe for use. The system described herein is beneficial in that it avoids the skill / time required to prepare conventional shisha pipes for smoking. Instead a simple, single-use, pre-filled capsule can be inserted into the device. The capsule can simply be ejected after use and reduces the cleaning time needed for conventional shisha pipe bowls. Furthermore the session may have a predetermined time or power consumption such that the session management is easier, e.g. with the base reporting when a session has expired or when the battery of the base is low. Turning now to figure 14 there is shown an exploded view of the base 110 unit. The base 110 comprises, in height / stacked order: - upper surface 114 having the lighting array 130 extending around its periphery; - housing 112 defining the side wall of the base. The housing has an aperture 134 to receive a panel 136 for mounting of the button 128 and connector 126; - an internal chassis member 138 for housing electrical components, and to the side of which the electrical connector 122 can be mounted; - energy store in the form of a battery 140 (e.g. having one or more cells) - control circuit 142 - annular support plate 144 mounted on a bearing ring 146 arranged for rotation about a central / vertical axis of the base; - base plate 148 supporting the bearing ring and having a track to constrain motion / rotation of the bearing ring. The support plate 144 and electrical components may be mounted within the housing 112 so that they form a common subassembly. This assembly forms a rotatable portion of the base that is carried on the bearing ring 146. Thus the rotatable portion of the base can swivel or rotate upon the base plate 146. Other forms of rotation mechanism e.g. with a spindle or stem, e.g. akin to a turntable, or other wheeled arrangements. The common mounting of the electrical components in the upper / rotating portion means that electrical connections do not need to be passed over the rotating interface but can instead rotate I unison with the water pipe device 2 in use. The starting and stopping of a usage session may be controlled by the controller in the water pipe device 2, e.g. as well as controlling the heating regulation for the heating chamber. This may be in communication with the controller 142 of the base. Additionally or alternatively, this could be controlled from the base. The base can output the remaining session duration, remaining battery charge, end of session and / or other parameters via the indicator so that an operator can readily appreciate whether the base needs to be changed, the water pipe session needs to be renewed, or the like, quickly and simply, e.g. whilst the device 2 is on the base. A simple, single connector 122 between the base and water pipe device allows easy setup, attachment, detachment and replacement of a water pipe for convenience. The base maty also provide for added security, i.e. such that the water pipe device can only be used with specified or identifiable devices. The base and / or device may carry an ID which may be communicated to the other of the base and device upon connection thereto. The heater of the device and / or battery of the base may only be operable for supply of electric power therebetween in the base / device is recognised. A digital / security handshake may be performed for use. Encryption can be used for secure verification. One of the base / device may comprise a log of approved ID’s such that it can match the ID of the connected base / device. 5 In additional / alternative embodiments, the base can sense the connection of a waterpipe device automatically, through either a mechanical means, resistance means or a capacitance means, and will not provide power through the connectors until a successful connection is sensed. Thus the base can monitor an electrical or mechanical parameter (e.g. in addition to or instead of a data communication) in order to establish a scenario in 10 which power can be supplied or denied.

Claims

1. An electric water pipe system comprising:a water pipe device having:a heating chamber arranged to receive a consumable product, the heating chamber having an air inlet and an electric heater for heating the consumable product;a liquid reservoir arranged to contain a coolant and having an air outlet leading to a mouthpiece;a gas pathway passing from the heating chamber into the liquid reservoir whereby a user can draw air in use through the water pipe device by suction using the mouthpiece; and, the water pipe system further comprising a base for the water pipe whereby the water pipe is releasably mountable upon the base in use, the base comprising an electrical energy store and an electrical connector for powering the water pipe device when mounted upon the base.

2. An electric water pipe system according to claim 1, wherein the electrical energy store is rechargeable and has a capacity sufficient to power the water pipe device during active use by a user for in excess of three hours, four hours, five hours or six hours.

3. An electric water pipe system according to claim 1 or 2, wherein the consumable product is provided in one or more pre-packed capsule of consumable material arranged to be received by the heating chamber.

4. An electric water pipe system according to claim 3, wherein the capsules are single use capsules containing a predefined portion of consumable material for a single usage session and have a predetermined session duration associated with the capsule.

5. An electric water pipe system according to claim 3 or 4, wherein the capsules carry session duration information, e.g. of at least 30 minutes, 45 minutes or 60 minutes.

6. An electric water pipe system according to any one of claims 3-6, wherein the electric energy store has a capacity sufficient to power the electric water pipe in use to consume a plurality of capsules.

7. An electric water pipe system according to any preceding claim, wherein the water pipe device is seated upon the base such that the base serves as a pedestal for the water pipe device and the weight of the water pipe device is supported by the base.

8. An electric water pipe system according to any preceding claim, wherein the liquid reservoir of the water pipe device is seated upon the base.

9. An electric water pipe system according to any preceding claim, wherein the base may be is recessed and profiled to receive the water pipe device with a close fit.

10. An electric water pipe system according to any preceding claim, wherein an upper surface of the base and the underside of the water pipe device comprise corresponding engagement or alignment formations.

11. An electric water pipe system according to any preceding claim, wherein the heating chamber is above the liquid reservoir of the water pipe device and the gas pathway extends through an internal compartment between the liquid reservoir and heating chamber, the gas pathway being surrounded by gas within the internal pathway.

12. An electric water pipe system according to any preceding claim, wherein the base is rotatable.

13. An electric water pipe system according to claim 12, wherein the base comprises a lower member and an upper member, wherein the upper member is rotatable relative to the lower member and the upper member comprises the electrical connector and / or electrical energy store.

14. An electric water pipe system according to any preceding claim, wherein the base comprises one or more indicator or interface for indicating a usage session duration, expiry of a usage session; and / or, a charge status of the energy store.

15. An electric water pipe system according to claim 12, wherein the one or more indicator comprises an annular display or light extending at least part way around the base.

16. An electric water pipe system according to any preceding claim, wherein the base comprises one or more light arranged to illuminate the liquid reservoir of the water pipe device in use.

17. An electric water pipe system according to claim 15 or 16, wherein the light is variably controllable to illuminate at different intensity or geometric size / shape and / or to illuminate with different colours or different transient patterns.

18. An electric water pipe system according to any preceding claim, wherein the electrical connector bypasses the liquid reservoir.

19. An electric water pipe system according to any preceding claim, wherein the electrical connector is provided on an upstanding and / or flexible arm of the base, which spans the height of the liquid reservoir to connect with an electrical connector on a housing of the water pipe device above the liquid reservoir.

20. An electric water pipe system according to any preceding claim, wherein the electrical connection comprises a data connection between a controller of the water pipe device and a controller of the base.

21. An electric water pipe system according to any preceding claim, wherein the base comprises a manual interface or button which selectively permits or denies power supply to the water pipe device.

22. An electric water pipe system according to any preceding claim, wherein the base can sense a successful connection of a waterpipe device automatically upon connection therewith and will not provide power through the electrical connector until a successful connection is sensed.

23. An electric water pipe system according to any preceding claim, wherein the water pipe device is devoid of an onboard electrical energy store or is devoid of an onboard electrical energy store capable of supplying power for a duration greater than or equal to a single usage session.

24. A base unit for use in the electric water pipe system of any preceding claim wherein the base unit comprises an upper surface arranged to removably receive a water pipe device in a seated position thereon and the base unit comprises a rechargeable energy store for powering the electric heater of the water pipe device via a releasable electrical connection therewith when the water pipe device is seated on the base unit.

25. An electric water pipe device for use in the electric water pipe system of any preceding claim wherein the electric water pipe comprises the electric heater but is devoidof a power source for powering the electric heater, and wherein the water pipe device comprises an electrical connector for connecting to the base such that the water pipe device is only operable when connected thereto.

26. A method of using water pipe systems comprising:providing a plurality of water pipe devices each having: a heating chamber arranged to receive a consumable product, the heating chamber having an air inlet and an electric heater for heating the consumable product; a liquid reservoir arranged to contain a coolant and having an air outlet leading to a mouthpiece; a gas pathway passing from the heating chamber into the liquid reservoir whereby a user can draw air in use through the water pipe device by suction using the mouthpiece;providing a plurality of bases for the water pipe devices, each base comprising an electrical energy store and an electrical connector for powering the water pipe device when mounted upon the base;providing a consumable product in one water pipe device for a user and mounting said water pipe device to a base for use by the user.

27. The method of claim 26, further comprising removing a water pipe device form its base and connecting a further water pipe device to said base to initiate a further usage session.

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