The present invention relates to an airlock chamber for locating between passageways, the airlock chamber being adapted to house at least one vehicle.

The passageways define low-pressure regions and they may be substantially- evacuated of air. The passageways may form part of a high-speed transport system such as the Hyperloop system proposed by Elon Musk. The Hyperloop system comprises airtight tubes which are substantially-evacuated. Pressurised passenger or cargo vehicles, preferably in the form of capsules or pods, are designed to travel at high speeds through the tubes. By way of example, the pressurised vehicles may ride on an air cushion driven by linear induction motors and air compressors. The vehicles may be guided on rails when they slow down to approach and dock at a station.

The present inventors have addressed the problem of how to dock the vehicles for unloading and reloading. This is not straightforward since the passageways are maintained at low pressure and the vehicles are maintained at normal air pressure and are therefore pressurised with respect to the passageways. Also, the external environment, such as a station, where the vehicles are docked, is generally at normal air pressure (atmospheric pressure) and is therefore pressurised with respect to the passageways.

With a view to solving this problem, the inventors have devised the airlock chamber of the present invention. The present invention seeks to provide an airlock chamber for locating between low-pressure passageways and being adapted to house one or more vehicles at a station.

According to the present invention, there is provided an airlock chamber for locating between passageways, its interior being adapted to house one or more vehicles, the airlock chamber comprising at least one sealable doorway to provide access to the interior of the chamber via a side of the chamber; wherein the airlock chamber is elongate and the or each doorway provides access to the interior of the chamber along at least a portion of a longitudinally-extending side of the chamber; wherein the or each doorway is sealable with one or more arcuate doors; wherein the or each door is openable by rotation about the longitudinal axis of the airlock chamber; and wherein each of both ends of the chamber is provided with a sealable opening for permitting passage of a vehicle between the airlock chamber and an adjacent passageway.

The doorway is sealable with one or more doors, being openable barrier means. The airlock chamber has a longitudinal direction along the travelling direction of the vehicle. Access to the interior of the chamber is via a longitudinally-extending side of the chamber.

The airlock chamber is preferably generally cylindrical in shape. In geometry, the side of a cylinder is the surface area extending between its ends. According to the following description of the present invention, the airlock chamber is described as having two sides, even when it is generally cylindrical in shape. In the case of the airlock chamber having a generally cylindrical or similar shape, the two sides are those opposing regions of the surface area of the shape which are positioned to allow access to the interior of the chamber (even if access in fact happens only on one side of the chamber): for example, they may be the regions of the shape located adjacent to a surface (eg a platform) provided for passengers or cargo to embark and disembark a vehicle housed in the airlock chamber. According to the present invention, there is also provided an elongate airlock chamber for locating between passageways, its interior being adapted to house one or more vehicles, the airlock chamber comprising a first end, a second end, two sides and at least one sealable doorway to provide access to the interior of the chamber, the doorway or doorways being located between the first and second ends and providing access to the interior of the chamber via one or both sides of the chamber; wherein the or each doorway is sealable with one or more arcuate doors; wherein the or each door is openable by rotation about the longitudinal axis of the airlock chamber; and wherein each end is provided with a sealable opening for permitting passage of a vehicle between the airlock chamber and an adjacent passageway.

The airlock chamber is preferably adapted to accommodate a single vehicle, although it may be adapted to accommodate more than one vehicle at the same time. The vehicle may comprise one or more coaches and/or containers; for example it may be a train or a train-like vehicle.

Preferably the airlock chamber is adapted to closely accommodate a vehicle housed therein, such that the vehicle closely fits inside the airlock chamber. This is to provide a relatively small void between the external surface of the vehicle and the internal surface of the airlock chamber. The advantages of this close fit are explained with respect to the method of the invention, set out below.

In one embodiment, at least 75%, preferably at least 80%, more preferably at least 85% and most preferably at least 90% , of the interior volume of the chamber is adapted to be occupied by the external volume of the vehicle (or vehicles) housed therein. In other words, assuming an airlock chamber empty of any vehicle has an internal volume of 100%, when the vehicle (or vehicles) is fully enclosed in the airlock chamber, the remaining space (or void) in the interior volume of the chamber is reduced to 25% or less, preferably 20% or less, more preferably 15% or less, and most preferably 10% of less, compared with the initial, empty volume. In one embodiment, 85% to 95%, of the internal volume of the chamber is adapted to be occupied by the external volume of the vehicle or vehicles housed therein.

The airlock chamber seeks to define a variable-pressure region for locating between passageways defining low-pressure regions. These passageways may be substantially-evacuated of air (ie kept at vacuum or near-vacuum conditions). The passageways adjacent to the airlock chamber preferably have substantially equal air pressures therein.

A region of the outer surface of the chamber that comprises the doorway or a plurality of doorways preferably extends along at least half, and more preferably along at least two-thirds, of the length of the longitudinally-extending side of the chamber. As a result, the portion of the longitudinally-extending side of the chamber for providing access to the interior of the chamber (or the portion of each longitudinally-extending side of the chamber, if applicable) preferably extends along at least half, and more preferably along at least two-thirds, of the length of the longitudinally-extending side of the chamber.

One or more sealable doorways are provided along one or both sides of the chamber for accessing the interior of the chamber. Each doorway is sealable using one or more doors, being openable barrier means. The airlock chamber is elongate and the or each doorway provides access to the interior of the chamber along at least a portion of one or both longitudinally-extending sides of the chamber. The region of the outer surface of the chamber comprising the doorway or the plurality of doorways preferably extends along at least half, and more preferably along at least two-thirds, the length of one or both sides of the chamber (ie in the longitudinal direction). This enables access to a corresponding length of the docked vehicle and also enables rapid air flow between the internal space in the airlock chamber and the environment external to the airlock chamber. This external environment is that on the externa l side of the door(s) and is distinct from the environment in the adjacent passageways. I n one embodiment, the region of the outer surface of the chamber comprising the doorway or a plurality of doorways provides access to the interior of the chamber along substantially the length of the chamber along one or both longitudinally-extending sides of the chamber.

A plurality of the doors may seal one common doorway. Alternatively, the or each single door may seal a single doorway. When a doorway or a plurality of doorways is provided on each of both sides of the chamber to access the interior thereof, they provide access along opposite sides of the chamber. The door or doors for sealing the doorway(s) may be opaque or transparent or semi-opaque. In one embodiment they are glass doors which are sufficiently transparent to view a vehicle housed therein.

In a preferred embodiment, the airlock chamber is generally cylindrical in shape. For example, the chamber has sides and a roof section that are arcuate in cross-section such that the overall visual impression of the airlock chamber is of a cylindrical shape. The floor section of the chamber may also be arcuate in cross-section or it may be

substantially planar in a horizontal orientation (for example). At least one side of the chamber may be substantially defined by a door or by a plurality of doors sealing the doorway(s): the door or doors are arcuate and they, at least in part, may provide the external surface of the airlock chamber with a cylindrical appearance. It is optional whether the airlock chamber has a distinct roof section since the two sides of the chamber may meet at the uppermost point of the airlock chamber. Also, one or more doors, preferably arranged adjacent to one another along the length of the airlock chamber, may define substantially the whole outer surface of the chamber (excluding the floor section of the chamber) along at least half, and more preferably along at least two-thirds, of the length of one or both sides of the chamber (in the longitudinal direction): ie there are no separate roof and side sections: the door or doors may be curved to provide the preferred cylindrical shape of the airlock chamber.

It is important that when the door or doors are closed (ie the or each doorway is sealed), the airlock chamber is substantially airtight. The or each door may be provided with seals to prevent airflow into and out of the airlock chamber. For example, one or both of longitudinally-extending edges of the door may be provided with a seal. The edges of the door extending in the width direction of the door may also be provided with seals.

When the airlock chamber is closed (ie the door or doors are closed), a

longitudinally-extending edge of the or each door may meet and seal with the floor section of the chamber or with a surface (eg a platform) provided adjacent to the floor section of the chamber.

In one embodiment, an indented region or a channel is provided to accommodate a longitudinally-extending edge of the door. This region or channel may be provided in the floor section of the chamber or in a surface provided adjacent to the floor section of the chamber.

The or each door may be adapted to open by moving in at least an initial direction which is perpendicular to the plane defined by a horizontal floor (if any) of the chamber (this direction may be perpendicular to the plane defined by a horizontal floor of a vehicle housed in the chamber).

The door or doors may be arranged to open by moving upwards, in a direction which is away from the floor section of the chamber.

When the airlock chamber comprises a doorway or a plurality of doorways on opposing sides of the chamber, the arcuate door or doors for sealing the doorway are openable by rotation about the longitudinal axis of the airlock chamber, the door(s) on each side preferably rotating in an upwards direction, being a direction which is away from the floor section of the chamber. In the case where the airlock chamber comprises the or each doorway on opposing sides of the chamber, the arcuate door or doors for sealing the doorway(s) may subtend an angle of 65 to 110 degrees, preferably 70 to 90 degrees and more preferably about 80 degrees, from the central point of the cross-section of the airlock chamber, the cross- section being taken along a plane perpendicular to the longitudinal axis of the airlock chamber. When the airlock chamber is substantially cylindrical in shape, this central point is the centre of the circle defined by the airlock chamber in cross-section.

When the airlock chamber comprises a doorway or a plurality of doorways only on one side of the chamber, the arcuate door or doors for sealing the doorway(s) may subtend an angle of 240 to 290 degrees, preferably 250 to 270 degrees, from the central point of the cross-section of the airlock chamber, the cross-section being taken along a plane perpendicular to the longitudinal axis of the airlock chamber. When the airlock chamber is substantially cylindrical in shape, this central point is the centre of the circle defined by the airlock chamber in cross-section.

The or each door may be openable by rotation about the longitudinal axis of a substantially cylindrically-shaped airlock chamber. In one embodiment, the or each door has a C-shape in cross-section, the cross- section being taken along a plane perpendicular to the longitudinal direction (longitudinal axis) of the airlock chamber. The or each door therefore has a C-shaped profile.

The door or doors may be in the form of a rotating drum. Accordingly, when the airlock chamber is closed, both longitudinally-extending edges of the door(s) may meet and seal with the floor section of the chamber or with a surface (eg a platform) provided adjacent to the floor section of the chamber.

When the door or doors have a C-shaped profile, they may define substantially the whole visible outer surface of the airlock chamber (ie there are no separate roof and side sections) along at least half, and more preferably along at least two-thirds, the length of one or both sides of the chamber. The visible outer surface may exclude the floor section of the chamber. Preferably the airlock chamber is provided with one or more large doorways: by way of example, the doorways are sealed with door or doors having a C-shaped profile. As a result of the large doorways, the doors of a vehicle housed in the airlock chamber may have doors similar to those used in aeroplanes: such doors open outwardly and therefore maximise the internal volume of the vehicle. By providing large doorways to the airlock chamber, the vehicle doors can be opened without being obstructed by door frames and other support structures. The use of the C-shaped doors therefore helps to keep the volume of the void between the external surface of the vehicle and the internal surface of the chamber to a minimum. The airlock chamber may be accessed on one side only and the or each door may rotate away from the access side of the chamber, thereby allowing access to a docked vehicle. The leading edge of the door during the rotation movement may be

accommodated on the non-access side of the chamber: for example, the door may rotate into, and its leading edge be housed in, a correspondingly-shaped channel provided in the floor section of the chamber or provided in a surface (eg a platform) provided adjacent to the floor section of the chamber.

In another embodiment, the doorway or a plurality of doorways provide access along opposite sides of the chamber. In this respect, at least one door is provided on a first side of the chamber and at least one door is provided on a second, opposite side of the chamber. The doors on the opposite sides may each be adapted to be moved either upwards or downwards with respect to the floor section of the airlock chamber. For example, the doors may be rotated in an upwards direction for housing in a roof section of the airlock chamber. Alternatively they may each be rotated in a downwards direction to be housed in a correspondingly-shaped channel provided in the floor section of the chamber or provided in a surface (eg a platform) provided adjacent to the floor section of the chamber. In another embodiment, the door on one side may be moved in an upwards direction and the door on the other side may be moved in a downwards direction with respect to the floor of the airlock chamber.

In one embodiment it is envisaged that each airlock chamber is provided with three or four arcuate doors extending along the length of the airlock chamber to provide access along only one side of the chamber: these doors may all seal one common doorway or they may each seal an individual doorway. However there is no particular limit to the number of doors or doorways provided. Also, one or more doors may be provided along each side of the airlock chamber.

The door(s) may be locked in an open and/or a closed position using an

electromagnetic mechanism. Each door may be provided with one or more steel or other metal inserts to allow the doors to be locked using the electromagnetic mechanism.

The two ends of the airlock chamber (ie the first end and the second end) are, generally-speaking, opposite one another. However, these ends may not be directly oppositely one another in a linear sense (although this is a preferred arrangement). For example, the ends may be offset from one another, or the airlock chamber may have a curvature along its length such that the ends are opposite one another in a non-linear sense.

Each end is preferably sealable with a gate to provide a substantially airtight seal.

The cross-sectional shape of the airlock chamber, as viewed in a plane

perpendicular to the longitudinal direction (longitudinal axis) of the chamber, is preferably circular. However, the floor section and/or the roof section (if any) may be planar, thereby defining one or more chords of the circle and meaning that one or more segments may be absent from the generally circular shape. It is envisaged that the airlock chamber may have other cross-sectional shapes: for example, it may have a substantially oval, substantially square or substantially rectangular cross-sectional shape.

The floor section of the airlock chamber is the bottom section of the chamber. It is preferably provided with a support structure for the vehicle(s). In one embodiment it is provided with rails for guiding the vehicles, in the manner of a railway track, for example. The floor section of the chamber may also be provided with other substructures and electrical installations necessary for the operation of the airlock chamber.

One or more structural members may extend around and/or form at least part of the outer surface of the chamber to support the doors. These structural members are preferably arranged in a plane which is perpendicular to the longitudinal direction

(longitudinal axis) of the chamber. In one embodiment, the airlock chamber may be provided with one or more structural members to support the doors using interstitial rails or other door support means. Each structural member may be provided with means to support, and preferably to seal, the edges of the doors adjacent thereto (these may be side edges of the doors extending in the width direction of the doors when the doors have a length direction which extends in the longitudinal direction of the chamber). The structural members may be provided with cavities to house structures and installations for operating the airlock chamber. The structural members may support rails for guiding vehicles, particularly in the floor section of the chamber.

In one embodiment, a generally-cylindrical airlock chamber may be provided with one or more structural rings or arcs which extend around at least part of the

circumference of the chamber to support the doors.

The present invention provides a method for using the airlock chamber of the invention, wherein the airlock chamber is connected to an entry passageway at or adjacent to its first end and is connected to an exit passageway at or adjacent to its second end. The entry passageway and the exit passageway are for a vehicle to enter or exit the airlock chamber. The passageways may be tubular and co-axial.

The method of the present invention comprises: a) sealing the doorway or doorways of the airlock chamber and unsealing at least the opening of the first end; wherein the air pressure in the closed airlock chamber is substantially equalized with the air pressure in the adjacent entry passageway; b) receiving a vehicle or vehicles from the entry passageway and housing the vehicle or vehicles in the closed airlock chamber ; c) sealing the opening of the first end of the airlock chamber and, if unsealed, sealing the opening of the second end of the airlock chamber; d) unsealing the doorway or doorways of the airlock chamber; wherein the air pressure in the open airlock chamber is substantially equalized with the air pressure of the

environment external to the airlock chamber (the external environment not including the entry and exit passageways); e) sealing the doorway or doorways of the airlock chamber and unsealing at least the opening of the second end of the airlock chamber ; wherein the air pressure in the closed airlock chamber is substantially equalized with the air pressure in the adjacent exit passageway; and f) moving the vehicle or vehicles from the airlock chamber into the exit passageway.

The air pressure in the entry passageway is preferably substantially equal to the air pressure in the exit passageway.

When no vehicle is housed in the airlock chamber, the opening of the first end is open and/or the opening of the second end is open. In this way the air pressure in the airlock chamber is in equilibrium with the air pressure in the respective adjacent passageways. Given the small internal volume of the airlock chamber relative to the volume of the adjacent passageways, and given the relatively low air pressures involved, there is no need, in a preferred embodiment, to provide a pumping system to achieve this equalization of air pressures. As a result, sealing the doorway or doorways of the airlock chamber and unsealing at least the opening of the first end allows substantial equalization of the air pressure in the closed airlock chamber with the air pressure in the adjacent entry passageway (and in the adjacent exit passageway if the opening of the second end is also unsealed).

A vehicle travelling through a transport system approaches and enters the airlock chamber in its entirety. The opening of the first end is sealed as is the opening of the second end (if not already sealed).

The vehicle preferably substantially fills the airlock chamber. Since the vehicle has entered the airlock from a low-pressure passageway, the air pressure in the space between the external surface of the vehicle and the internal surface of the airlock chamber is relatively low and below atmospheric pressure (it is at substantially the same air pressure as the low-pressure passageway).

Preferably, the volume of the space between the external surface of the vehicle and the internal surface of the airlock chamber is designed to be as small as possible. Since the volume of this space is small, and preferably minimal, the air pressure of the space between the external surface of the vehicle and the internal surface of the airlock chamber rapidly equalizes with the air pressure of the external environment. I n a preferred embodiment, there is no need to provide separate means for substantially equalizing the air pressure in the closed airlock chamber with the air pressure of the external environment, which is generally at atmospheric pressure. As a result, unsealing the doorway or doorways of the airlock chamber allows substantial equalization of the air pressure in the open airlock chamber with the air pressure of the environment external to the airlock chamber. The interior air pressure of the vehicle is generally maintained at substantially atmospheric pressure. Once the door of the airlock chamber is open, the door or doors of the vehicle can be opened for docking purposes. For example, passengers and/or cargo can leave and enter the vehicle. Therefore, between steps (d) and (e) above, passengers or cargo can enter and exit the vehicle via the doors of the vehicle, these doors being substantially airtight.

When a vehicle is ready to depart from the airlock chamber into the exit passageway, the doors of the vehicle are closed to maintain an internal pressurised environment (ie the interior of the vehicle will be at atmospheric pressure). The door or doors of the airlock chamber are then closed, thereby sealing the doorway or doorways. At this point the pressure of the air in the space between the external surface of the vehicle and the internal surface of the airlock chamber is substantially at atmospheric pressure.

It is envisaged that filtering means may be associated with the sealable openings of the ends of the airlock chamber. The filtering means may be present to filter out dust and other debris from the air present in the airlock chamber once it has been exposed to the external environment. The filtering means aims to prevent dust and other debris entering and contaminating the adjacent passageways.

In this respect, the following steps may be taken when unsealing the opening of the first or second end of the airlock chamber after the airlock chamber has been exposed to the external environment. In step (e) of the above method, for example, a valve with a filter is opened until the air pressure in the closed airlock chamber is substantially equalized with the air pressure in at least the adjacent exit passageway; the opening of at least the second end of the airlock chamber is then unsealed to allow the vehicle to depart the chamber. A valve with a filter may be associated with each sealable opening of the chamber: each valve may be associated with a means for sealing each opening of the chamber; for example, each opening may be sealable with a gate provided with the valve. When the vehicle is ready to depart, the opening of the second end of the airlock chamber is unsealed and, optionally, the opening at the first end of the airlock chamber is unsealed. The pressured air in the airlock chamber (but not in the vehicle) rapidly vents into the adjacent passageway or passageways either through the unsealed opening(s) or through the valve with a filter associated therewith. There is no need, in a preferred embodiment, to provide separate pumping means for equalizing the air pressure in the airlock chamber with the air pressure in the adjacent passageway(s). Instead, sealing the doorway or doorways of the airlock chamber and venting the air inside the chamber by unsealing at least the opening of the second end of the airlock chamber or using an associated valve allows substantial equalization of the air pressure in the closed airlock chamber with the air pressure in the adjacent exit passageway (and in the adjacent entry passageway if the opening of the first end is also unsealed).

Once the opening in the second end of the airlock chamber is open, the vehicle is able to exit the airlock chamber through the second end and into the exit passageway and beyond.

The present invention also provides a series of airlock chambers, each being located between entry and exit passageways. The airlock chambers may or may not be arranged in parallel and may or may not be interconnected.

One or more airlock chambers may be provided at a station concourse. The station concourse may comprise at least one airlock chamber having a passenger platform arranged adjacent thereto. If a series of airlock chambers are provided, a common passenger platform may be located between adjacent airlock chambers.

A plurality of distinct entry and exit passageways may be provided at the same station concourse, each pair of entry and exit passageways being connected to an airlock chamber of the present invention. The direction of travel of the vehicle defines the entry passageway and the exit passageway since the direction of travel through the airlock chamber may change.

In one embodiment it is envisaged that a transport system has a main passageway (primary passageway) connecting destinations (stations) on the system. The primary passageway may branch into a plurality of secondary passageways for the purpose of docking vehicles at a station concourse. The entry and exit passageways of the present invention may be secondary passageways branching from the primary passageway. The airlock chamber of the present invention is used to equalize pressure between a low-pressure region and a high-pressure region. The low-pressure region is that defined by the passageways adjacent to the airlock chamber (which passageways are preferably substantially-evacuated of air) and may include a large volume of connected passageways (eg a primary passageway and secondary branches thereof). In one example, the low- pressure region has a pressure of about lOkpa. The high-pressure region is that outside of the passageways and the airlock chamber (ie on the external side of the sealable doorway(s) of the airlock chamber) and is likely to be at atmospheric pressure, for example about lOOkpa. The entry and exit passageways are generally large chambers which are preferably kept at vacuum or near-vacuum conditions. This may be achieved by continuous pumping in order to compensate for general leakage losses in the transport system. This pumping system is preferably not additionally used to carry out the specific air pressure

equalization steps set out in the above method, since it is preferred that these steps occur naturally when the relevant openings (and/or their associated valves) are unsealed. The station concourse is also a large chamber, generally provided at atmospheric pressure.

The sealable doorway(s) of the airlock chamber, together with the sealable openings of the gateways provided at each end of the chamber and any valves associated with the openings, are preferably adapted to provide a pressure equalization mechanism for the airlock chamber.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:

Figure la is a perspective view of an empty airlock chamber according to a first embodiment with a closed door;

Figure lb is a perspective view of an empty airlock chamber according to the first embodiment with an open door;

Figure 2 is a perspective view of an airlock chamber according to a second embodiment with an open door and housing a vehicle;

Figure 3a is a cross-sectional view of an empty airlock chamber according to the second embodiment with the door closed;

Figure 3b is a cross-sectional view of an airlock chamber according to the second embodiment with the door open and housing a vehicle with its doors open;

Figure 4 is a perspective view of an empty airlock chamber according to a third embodiment with closed doors;

Figure 5 is a perspective view of an airlock chamber according to the third embodiment with open doors and housing a vehicle;

Figure 6a is a cross-sectional view of an empty airlock chamber according to the third embodiment with the doors closed;

Figure 6b is a cross-sectional view of an airlock chamber according to the third embodiment with the doors open and housing a vehicle with its doors open; and

Figures 7a to 7i are plan views of an airlock chamber showing a method of using the airlock chamber.

Referring to the Figures, an elongate, cylindrically-shaped airlock chamber 2 has a first end 4 and an opposite second end 6. The first end 4 is provided with an opening 8 and the second end 6 is provided with an opening 10. Each opening is sealable with a gate 12 as shown in Figure la (but omitted from Figures lb to 8 for clarity). Each end operates as a gateway into an adjacent passageway.

First end 4 is connected to an entry passageway 14 and second end 6 is connected to an exit passageway 16 (see Figures 7a to 7i).

The airlock chamber has a door 18 which provides access to the interior of the chamber via a doorway.

A platform 20 is arranged adjacent one or both sides of the airlock chamber. The platform is shown to be in approximately the same plane as a horizontal floor 24, which represents the floor of a vehicle to be housed in the airlock chamber.

In the first embodiment, shown in Figures la and lb, a door 18 is substantially C- shaped in cross-section and has a drum-shaped configuration. The door seals a doorway and extends along a sufficient length of the side of the chamber to provide access to the door or doors of a vehicle housed therein.

In this embodiment, the door extends along the length of the chamber but not along its whole length (which is shown by dashed lines in Figure la but omitted from Figure lb for clarity). The door preferably forms the external visible surface of the airlock chamber along at least half, and more preferably along at least two-thirds, the length of the chamber. However, other door configurations are envisaged including the provision of a plurality of adjacent doors extending along at least part of the length of the airlock chamber on one or both sides thereof. Such a configuration is shown in Figures 2, 4 and 7 relating to the second, third and fourth embodiments respectively (which are described in more detail below). Referring to Figures la and lb, the platform 20 is arranged adjacent one or both sides of the airlock chamber and the longitudinally-extending edges of the door meet and seal with the platform surface on either side of the vehicle housed therein when the door is closed. The longitudinally-extending edges of the door may be provided with seals.

The C-shaped door rotates away from the platform about the longitudinal axis of the airlock chamber, as shown in Figure lb, to expose a side of a vehicle housed therein and to allow access to the vehicle. When in its open position, the door prevents access to the other side of the vehicle.

The leading edge of the door is therefore adapted to rotate around the

longitudinal axis of the chamber to open the door (as shown by the arrows in Figure lb). To close the door, the trailing edge of the door rotates back around the longitudinal axis of the chamber.

When the door is open, its leading edge and the region of the door adjacent thereto are housed in a correspondingly-shaped channel 26 provided in the floor section of the chamber or provided in a surface (eg a platform) provided adjacent to the floor section of the chamber.

Referring to Figure 2, in a second embodiment of the invention, each door is C- shaped in accordance with the first embodiment. Structural rings 30 extend around the circumference of the chamber to support the doors using interstitial rails or other door support means. Each structural ring is provided with means to seal the side edges of the doors adjacent thereto, these side edges being supported by the structural ring. In this embodiment, three C-shaped doors are shown, supported by a pair of structural rings 30. The doors each have a length direction which extends in the longitudinal direction of the chamber; the side edges of the doors extend in the width direction of the doors. In Figure 2, a vehicle (train) is housed in the airlock chamber. Since the doors of the airlock chamber are open, the doors 28 of the vehicle are visible. Upon opening these doors, passengers can disembark from the vehicle. The series of three doors of the second embodiment extend along the length of the chamber but not along its whole length (which is shown by dashed lines); it is sufficient in this embodiment that the doors extend along a sufficient length of the side wall of the chamber to provide access to the vehicle doors. In this embodiment, the region of the outer surface of the chamber comprising the series of doors (and doorways) extends along more than two-thirds of the length of the side of the chamber.

Figures 3a and 3b are cross-sectional views of the airlock chamber of the second embodiment. In Figure 3a, the C-shaped doors are closed. It can be seen that the longitudinally-extending edges of each door meet and seal with the longitudinally- extending ends of the channel 26. Also, rails 32 for guiding a vehicle are provided in the floor section of the chamber.

Rails 32 may be mounted on the structural rings 30. The structural rings preferably allow structures such as rail supports and substructures of the vehicles to be mounted on the rings, using cavities within the rings, each ring being located adjacent to one or more doors of the airlock chamber.

Figures 3a and 3b show a counter bearing 40 to allow sealing of the longitudinally- extending edges of the doors. Sealing may be achieved using an electromagnet pressing the door into a sealing material. Such counter bearings may also be used in the other embodiments of the invention.

In Figure 3b, the C-shaped doors are open and the leading edge of the door and the region adjacent thereto have retracted into the channel 26 by rotating about the longitudinal axis of the chamber. A vehicle is housed in the chamber and its doors are open on the access side of the chamber. As marked by the arrow shown, passengers or cargo are able to enter or exit the vehicle. In Figure 3b, a base section 42 of the vehicle 22 is mounted on the rails 32.

In the first and second embodiments, where the airlock chamber comprises a doorway or a plurality of doorways only on one side of the chamber, the arcuate door or doors for sealing the doorway(s) may subtend an angle of 240 to 290 degrees, preferably 250 to 270 degrees, from the central point of the cross-section of the airlock chamber, the cross-section being taken along a plane perpendicular to the longitudinal axis of the airlock chamber. Since the airlock chamber is substantially cylindrical in shape, this central point is the centre of the circle defined by the airlock chamber in cross-section.

In the third embodiment, with reference to Figures 4 and 5, a plurality of doorways provides access along opposite sides of the chamber. In this respect, four doorways, each sealed by an arcuate door, are provided on a first side of the chamber and four doorways, each sealed by an arcuate door, are provided on a second, opposite side of the chamber.

Structural rings 30 extend around at least part of the circumference of the chamber to support the doors using interstitial rails or other door support means. In this embodiment, each side of the chamber has four arcuate doors 18, supported by three structural rings 30.

The doors on the opposite sides of the chamber are adapted to be moved upwards with respect to the floor section of the airlock chamber. Referring to Figures 4, 5 and 6, the doors are rotated in an upwards direction into a roof section 34 of the airlock chamber. Alternatively they may each be rotated in a downwards direction to be housed in a correspondingly-shaped channel provided in the floor section of the chamber or provided in a surface (eg a platform) provided adjacent to the floor section of the chamber. In Figure 5, a vehicle (train) is housed in the airlock chamber. The doors 28 of the vehicle face a doorway of the chamber. Since the doors 18 of the airlock chamber are open, the doors 28 of the vehicle are visible. Upon opening these doors, passengers can disembark from the vehicle.

The doors of the third embodiment extend along the length of the chamber but not along its whole length (which is shown by dashed lines in Figure 5 but is omitted from Figure 4 for clarity); it is sufficient in this embodiment that the doors extend along a sufficient length of the side wall of the chamber to provide access to the vehicle doors. In this embodiment, the region of the outer surface of the chamber comprising the series of doors (and doorways) extends along more than two-thirds of the length of the side of the chamber.

Figures 6a and 6b are cross-sectional views of the airlock chamber of the third embodiment. Referring to these Figures and to Figures 4 and 5, it can be seen that the longitudinally-extending lower (trailing) of the doors in the doorways meet and seal with the platform edges 36 on both sides of the vehicle when the airlock is closed.

In this embodiment, each platform edge 36, where it meets the floor section of the chamber, is provided with a longitudinal channel for accommodating the longitudinally- extending lower (trailing) edge of the door in a closed, sealed position. Alternatively, an indented region or channel may be formed in the floor section of the airlock chamber to accommodate the longitudinally-extending lower (trailing) edge of the door in a closed, sealed position.

Referring to Figures 6a and 6b, rails 32 for guiding a vehicle are provided in the floor section of the chamber.

In Figure 6b, the arcuate doors are open and have retracted into the roof section 34 of the chamber by rotating about the longitudinal axis of the chamber. A vehicle, with a roof 38, is housed in the chamber on top of the rails and its doors are open on both sides of the chamber. As marked by the arrows shown, passengers or cargo are able to enter or exit the vehicle along both of its sides. Figure 6b shows the base section 42 of the vehicle mounted on the rails 32.

In the third embodiment, where the airlock chamber comprises doorways on opposing sides of the chamber, the arcuate doors for sealing the doorways may subtend an angle of 65 to 110 degrees, preferably 70 to 90 degrees and more preferably about 80 degrees, from the central point of the cross-section of the airlock chamber, the cross- section being taken along a plane perpendicular to the longitudinal axis of the airlock chamber. Since the airlock chamber is substantially cylindrical in shape, this central point is the centre of the circle defined by the airlock chamber in cross-section.

The doors in all of the embodiments are arcuate. In one embodiment the doors of the airlock chamber are curved (for example, they have an extruded C-shape) and are made of glass or another transparent material. In one example, each door is a glass pane which is 24mm thick and is curved with a 1.5m radius. The doors may be manufactured in 10m sections: for example each door may be 2.2m wide and 10m long (eg in the third embodiment of the invention). Each door may be supported by and sealed along interstitial rails. Each door may be provided with steel (or other metal) inserts for electromagnetic locking in both the open and closed positions of the door.

Figures 7a to 7i illustrate schematically the method of the invention using the airlock chamber of any of the embodiments of the present invention. The airlock chamber has separation marks to indicate that the precise length of the chamber is not essential: it can be of any length.

Although a single door 18 is described in relation to Figure 7, the door allowing access along one side of the chamber, a plurality of doors 18 may be used instead. Also, one or more doors may be provided on each side of the chamber. The invention is not limited to the number of doorways or doors. An embodiment is envisaged where a single doorway is provided along each opposing side of the chamber, the doorway being sealable with one or more doors. Figure 7a shows an empty airlock chamber with the doorway of the chamber closed and sealed with door 18 and with the opening 8 unsealed (the gate of the first end of the chamber is open); a vehicle 22 is approaching from the entry passageway 14.

Opening 10 of the second end, adjacent the exit passageway 16, is sealed with gate 12. Figure 7b shows the vehicle 22 housed in the airlock chamber with the door 18 of the airlock chamber closed (the doorway is sealed).

Figure 7c shows the vehicle housed in the airlock chamber with the door 18 closed and with both end gates 12 closed, thereby sealing the airlock chamber.

The external volume of the vehicle fills approximately 85% to 95% of the interior volume of the airlock chamber, in this example. The air pressure in the remaining unoccupied space in the airlock chamber is approximately equal to that in the adjacent substantially-evacuated passageways which may have an air pressure of lOkpa.

Figure 7d shows the end gates 12 shut and the door 18 open (the doorway is unsealed). The opening of the doorway means that the interior of the airlock chamber is in fluid communication with the external environment. The large surface area of the door, and the corresponding aperture (doorway) created in the side of the chamber, means that air rapidly moves between the external environment and the internal environment of the airlock chamber (as shown by the arrows), such that the air pressure in the small space between the external surface of the vehicle and the internal surface of the airlock chamber rapidly reaches atmospheric pressure (ie there is rapid equalization of air pressure between the internal environment of the airlock chamber and the atmospheric pressure of the platform environment). Figure 7e shows the door 18 of the airlock chamber open and also the door or doors of the vehicle open, thereby allowing movement passengers or goods between the interior of the vehicle and the platform (as represented by the arrows shown).

Figure 7f shows the vehicle doors shut and sealed after emptying and/or loading of the vehicle. The vehicle is substantially airtight such that the atmospheric pressure inside the vehicle is maintained during its movement through the transport system.

Figure 7g shows the door 18 of the airlock chamber closed and sealed. The unoccupied internal space of the airlock chamber is at atmospheric pressure. However it may also contain dust and debris from the external environment.

The following steps may therefore be taken when unsealing the opening of the first or second end of the airlock chamber after the airlock chamber has been exposed to the external environment, using a valve with a filter associated with each end opening of the chamber. In this respect, each gate 12 may be provided with a valve having a filter.

First, the valve with a filter is opened until the air pressure in the closed airlock chamber is substantially equalized with the air pressure in the adjacent exit and/or entry passageway; then, the opening of at least the second end of the airlock chamber is unsealed to allow the vehicle to depart the chamber.

Figure 7h shows opening 10 in the second end 6 unsealed (the gate of the second end of the chamber is open); air within the unoccupied space in the airlock chamber has vented, either through a valve or by opening the gate, into the adjacent exit passageway 16. This equalizes the pressure between the airlock chamber and the exit passageway.

Figure 7i shows the vehicle 22 departing the airlock chamber through opening 10 of the second end 6 into the exit passageway 16. The vacated airlock chamber is then ready to receive the next vehicle therein from the entry passageway 14 for docking purposes.

The airlock chamber may be used in a station environment for the loading and unloading of passengers and/or cargo.

In one embodiment, each airlock chamber is tubular and closely accommodates a vehicle to be docked at the station platform. The close fit between the vehicle and the chamber minimises the volume of the space between the external surface of the vehicle and the internal surface of the chamber and thus minimises the amount of air which needs to be introduced or evacuated when the airlock chamber is in use. This in turn minimises the time taken to perform the pressurisation and depressurisation cycles when using the airlock chamber, without needing to provide a separate pumping system. This assists in providing a short dwell time of the vehicle in the airlock chamber and contributes to the aim of achieving swift docking for high volume usage of the system; for example, it maximises passenger capacity in the transport system for which the airlock system is used.

The preferred elongate shape of the airlock chamber enables the chamber to be opened along a substantial length of the chamber on one or both sides thereof. In view of the close fit between the vehicle and the airlock chamber, a relatively small amount of air rushes from the station platform area into the space between the vehicle and the chamber, thereby pressuring the chamber. This enables the vehicle doors to be readily opened for passengers or cargo, for example, to enter and exit the vehicle.

Similarly, when the vehicle is ready to leave the station and the vehicle doors are closed, the doors of the airlock chamber are closed to leave a relatively small volume between the external surface of the vehicle and the internal surface of the chamber. When gate 12 (or its associated valve with a filter) is opened into the exit passageway the small amount of air in this space is vented into the passageway, depressurising the airlock chamber.

The volume of the space between the external surface of the vehicle and the internal surface of the chamber is relatively small and preferably negligible in comparison to the volumes of the adjacent passageways and of the station environment. Thus, the venting process of the space, when both pressurising and depressurising the airlock, has little impact on the pressures of the external (station) environment and of the adjacent passageways.

This has the advantage of minimising the time required to achieve pressure equalization, and both minimises and simplifies the equipment required; for example, no mechanical pumping of air is required into or out of the airlock chamber. It also minimises the vehicle dwell time at the station which is a key parameter in sizing the station and therefore the overall cost of the docking system.