GB2406902A - Cooling and ventilation arrangement for an underground transit system - Google Patents

Abstract

A cooling system for an underground transit system utilises liquid oxygen as the medium in a heat exchanger 3 with unwanted oxygen vented to atmosphere, so as to provide cool oxygen enriched air. The cooled air may be stored under pressure in a pressurised air storage tank 1 for distribution at a pressurised service head 12 where it may be mixed with another gas by means of a servo or computer controlled mixer valve 13. The pressurised oxygen enriched air may be made available at air delivery units that are statically mounted along the length of a transit tunnel. The air delivery units being controlled by a statically mounted computer or dynamically mounted infrared signal sources (16, figure 2/2) upon trains. The air is delivered directly to the carriages of trains via receiver units (15, figure 2/2) when the receiver units (15, figure 2/2) are aligned with corresponding tunnel mounted air delivery units. The receiver units (15, figure 2/2) may feature filters and fan and baffle arrangements (17, figure 2/2) to redirect air flow. There may be 300 air delivery units per kilometre of track. Air may be delivered to train carriages when the train is stationary or moving. Within train carriages there may be provided sensors for monitoring the climate, these may include an oxygen sensor (18, figure 2/1) and a temperature and humidity sensor (19, figure 2/1). The energy used to bring about the transition of liquid oxygen to its gaseous state may be put to use.

Description

Magic Bullet Enriched Air Delivery This invention relates to the provision

of fresh air within the framework of an Underground Transit System, comprising of lrains or other motorised forms of transport, fixed installations such as Stations, Tunnels and Plant Rooms.

When trains, (or other forms of transport), travel underground it is essential to provide fresh air to the passengers. The lack of an adequate supply of fresh air is exacerbated in hot weather. Traditionally, trains have relied on the "Piston Effect" whereby the trains themselves create a partial vacuum as they travel along a tunnel, thereby inducing a draught in their wake.

Where the tunnels are particularly long and tortuous, such as in an Underground Transit System, the sources of air draught are provided by forced draught fans, (ED fans or "Blowers"), located at strategic points along the trajectory of the tunnel, and forcing air into the tunnel.

This system breaks down when there are an insufficient number of the fans or if the whole tunnel is populated by more and more trains. Any train that has stopped, clearly, not only does not induce a draught but it also acts as a cork.

This invention comprises a system of inter-connecting components installed in Two Locations. The first location is defined as the Static Location and comprises Plant Rooms, Stations, Platforms and Tunnels. The second location is defined as the Dynamic Location and comprises Rolling Stock, Buses, Trams and other forms of motorised transport.

The essence of the invention is for the Static Locations to provide fresh air and in particular fresh air enriched with Oxygen to the Dynamic Locations. My invention circumvents the shortcomings of the existing system by delivering fresh air or fresh Oxygenated Enriched Air to the train anywhere the train has stopped, and it does so using a fraction of the air required to dose the entire tunnel system.

Accordingly, In the context of an Underground Transit System this invention uses liquid Oxygen as a base material to provide Oxygen enrichment of safe breathable air directly inject-able into a train in addition to providing a means of cooling the resultant injected enriched air mass.

The enriched air to be injected is available to the train when it lines up close and adjacent to a Delivery unit. After alignment the train sends a signal to the Delivery Unit to inform it to commence injection of the enriched air. The train informs the Delivery Unit the flow-rate and duration of the injection it requires. There would probably be two injection points for each tube carriage, (or "Saloon"). All injection points are independently controlled according to the needs of the section of the Saloon that they serve. Infra-Red communication devices would be used because their communications are very localised and are unlikely to "cross-talk" with other Delivery Units not in their immediate vicinity.

A preferred embodiment of this invention will now be described with reference to the accompanying drawings in which: Figure 1 shows the extent of the invention comprised in the Static Location Figure 2 shows the extent of the invention comprised in the Dynamic Location With reference to Figure 1 the Static Location innovation comprises a source of fresh air stored in a Pressurised Air Storage Tank, (1) (for example such as scuba/diving gear tanks but much larger). An essential feature of this tank is that the air stored in this air tank shall have been compressed by an Air Compressor (2) from an air mass previously cooled by a Heat Exchanger (3) which energy extraction, (from the air), shall have been transferred to taking liquid Oxygen, contained within the Heat Exchanger's Primary Circuit, from its liquid state to a gaseous state and to about 5 C 30 C. The output of the liquid Oxygen input is now gas and that is passed through a Non-Return Valve (4) to be stored in a Low Pressure Oxygen Holding Tank (5).

The output of the Oxygen Holding Tank is fed via a Non-Return Valve (6) to a Compressor (7) which either feeds its output via a Non-Return Valve (8) to an Oxygen Service Head (9) or to a Pressurised Tank (10), similar to that of the compressed air. In that event the output of this Oxygen Pressurised Tank is then fed via a Non-Return Valve (8a) to the aforementioned Oxygen Service Head.

Similarly, the output of the Pressurised Air Storage Tank is also fed via a Non- Return Valve (11) to an Air Service Head (12).

We now have two service heads one filled with pressured air and the other with pressurised Oxygen.

These service heads are now take-off points for one or more Servo Mixer Valves (13), (controlled proportionally with feedback by an electronic system under the overall control of a Computer System).

The output of these Servo Mixer Valves are nowAir enriched with Oxygen at the Service head Pressures - both Oxygen and Air Service head having been maintained at equal pressures- (less any pressure drop occurring over the mixing valve). The pressurised output is directed in pipes to one or more Enriched Air Delivery Units (14). This Delivery Unit comprises an Electronic Microcontroller System, a Servo Flow and Pressure Regulator Valve, an Infra-Red Receiver and Transmitter, (Trans- receiver), and an Electrically Actuated Output Air Nozzle which operates in two modes, self cleaning and direct output.

The Microcontroller System controls the Air Nozzle actuation mode and the Servo Flow and Pressure Regulator Valve. It does so on the basis of signals it receives from the Infra-Red, (Transreceiver), Detector or from the Station's SCADA, (Supervisory, Control And Data Acquisition), system. In the event of a conflict the station's SCADA prevails.

The pressurised output from the Servo Mixer Valves can be fed to one or more of the previously mentioned Delivery Units "in parallel". When it is no longer possible for all connected Delivery Units to deliver a specified flow and pressure then another pipe run shall be installed to deliver another batch of Delivery Units. Alternatively, the Delivery Units shall be supplied on a "Ring System" similar to the manner in which Electrical power points are wired, where larger capacity mixers are used at the Service Heads.

In the case of the pressurised output being fed to Delivery Units located within a tunnel where there can be up to 300 such units per kilometre of track an important aspect of this Application is the disclosure of the fact, in the context of this invention, that at any given time probably not more than 10% of the Delivery Units will actually be in use. Although the pressurised enriched air feed supplies all 300 or more units, (i.e. the units are armed with pressurised enriched air), the air feed will only need to cope with, ("service in anger"), 10% of the supplied units, (in the case of 1 kilometre of track), being in actual use and that those 10% of units would be those units located immediately adjacent to a train stopped in the tunnel.

Another important aspect of this Application is the clear disclosure, in the context of this invention, that considerable energy is required to take Oxygen from its liquid form (-183 C) to around 5"C, when the Latent Heat of Vaporisation of Oxygen is taken into account. This input energy will be extracted from the air mass drawn in from the atmosphere and circulated around the Oxygen Heat Exchanger Sleeve before being collected for compression and storage in the Air Pressure Tank. The compressed air in this tank will, therefore, have been cooled below atmosphere temperature and when it is passed on to the Delivery Units and injected out at the nozzles it will be cooled air, relative to the prevailing atmospheric temperature.

Yet another important aspect of this Application is the clear disclosure, in the context of this invention, that the Microcontroller located in the Delivery Unit obtains its instruction on how to control the nozzle primarily from the Infra-Red Receiving Unit which in turn has been told what to communicate by the Microcontroller onboard the train, even though these instructions may ultimately be over-ridden if the Delivery Unit's Microcontroller receives countermanding or conflicting orders from the Station's SCADA system.

Figure 2/1 shows the General arrangement of the components within the train. With reference to Figure 2/2 the Dynamic Location aspect of this invention comprises a Receiver Port (15), installed and located in such a manner that it is best placed to receive air emanating from the Static Delivery Nozzles. (Delivery Units). This Receiver Port is electrically actuated so that it may be opened or shut. In the context of an underground train, for example, this port would be located on the side of the train. Located adjacent to the port is an Infra-Red Transmitter (16) (although it can also receive signals so in reality it is a Transreceiving Infra-Red Unit). Located immediately after the receiver port, which may containing a particle filter, would be an Electric Fan (17), which accepts an axial input of air and re-directs this air in a radial pattern. Ducts and direction vanes can then be provided to deflect and distribute the air flow evenly inside the train carriage. Within the train carriage would be found 3 Sensors, (and their Instruments), and these are an Oxygen Sensor (18), a Temperature Sensor, and a Humidity Sensor. Figure 2/1 shows a combined Temperature & Humidity Sensor (19). These sensors would report to their respective instruments. The instruments would each provide an output to an onboard Microcontroller Unit (20). This Microcontroller Unit would also be connected to the aforementioned Infra-Red Transmitter (Trans- receiver Infra-Red Unit).

Again in the context of a tube train there would be Receiving Ports/Motors on both sides of the train just as there are doors, on both sides of the train. Just as with the train doors the 'duty' of these ports would be varied, according to which side of the train the platform is.

The combined Static and Dynamic aspects of this invention is disclosed in the following manner: (An example of my invention) Liquid Oxygen is stored in a Plant Room away from the immediate vicinity of trains and passengers. In a second Plant Room closer to trains and passengers are located those items of Plant previously described and detailed and also depicted in figure 1.

Liquid Oxygen arriving from its Storage Plant is subject to a controlled entry at the Main Isolation Valve.

From this Isolation Valve onwards the liquid Oxygen enters a "Vaporiser" which is actually a Heat Exchanger. This Heat Exchanger obtains, (extracts), energy from a circulatory air mass that has been obtained from the atmosphere. The Oxygen exiting the Heat Exchanger is now in vapour form and is stored in a Low Pressure Tank. The Oxygen is now taken from this tank and compressed, the now compressed Oxygen may be stored in a High Pressure Tank, (optionally), or directly in the Oxygen Distribution Head, (Oxygen Service Head). From this Oxygen Distribution Head the Oxygen is fed to a Servo Mixer Valve. Meanwhile, the air mass which has been circulating around the Heat Exchanger sleeve chamber is extracted and compressed.

The output of this compressed air is stored in a Pressurised Holding Tank. This holding tank is connected to the Air Distribution Head. From this Air Distribution Head, (Air Service Head) the air is fed to the other leg of the Servo Mixer Valve previously mentioned. This feed arrangement may be repeated several times. A Computer controls the mixer and thus the proportion of Oxygen to be mixed with the air. (Both Oxygen and Air Distribution Heads are maintained at equal pressure). The output of the Servo Mixer Valve is taken via a pipe to feed one of several Delivery Units located on the far wall facing the platform. After the train enters the station it stops so that the Delivery Units are aligned, (roughly), with the Receiving Ports mounted on the train. Each carriage of the train opens its 2 Receiving Ports and turns on its Fan Motors. The train's Microcontroller sends an Infra-Red coded signal which informs the Microcontroller located inside the delivery unit by how much to open the Servo Valve and for how long to keep the nozzle open. The train Microcontroller will send such an Infra-Red signal only after it has received information about the air Oxygen mixture content of the enriched air at the Delivery Unit. The train's Microcontroller will have worked out how much enriched air it will require on the basis of its onboard Instruments and Sensors. If the Air/Oxygen mixture is inadequate for its needs the train will send, (via its Infra-Red link), a message to the Station's Computer to take action and inform the next station on the train's route to increase the air's enrichment. After the train had received its quota of enriched air it will shut down its Fans and close the Receiver Ports.

Should the train have to stop in the tunnel the driver will be reminded by his onboard computer inch the train forward, at most by 7.5 metros, (approximately), to align the Receiver Ports of his train with the Delivery Units in the tunnel. The train driver will then send a general signal to all the onboard Microcontrollers, (1 in each carriage), to let them know that they can receive air and on which side of their carriage to open their ports, (although this also may be automated). The Microcontroller(s) then orders the Tunnel Delivery Units to deliver enriched air.

So far I have addressed the two cases where the train has stopped at a Station and somewhere in the Tunnel. However there is the possibility where it may be required to feed enriched air to the train while it is on the move in the I unnel. In such a situation it would be possible to combine a third nozzle mode. This mode could be a "fan- shaped" air direction, (say 60 on either side of the normal). As the train travels within the tunnel sensors would detect the train and command only those Delivery Units adjacent to the train to inject out air in a "fan" configuration. Providing the air blast was sufficiently high then a large proportion of the ejected air would be absorbed by the passing train.

Claims (1)

1. - ,,,i, - ne;

   Claim I A cooling system for mass transit underground systems that utilises liquid oxygen as an indirect heat energy absorber by means of a heat exchanger interacting with normal air.

   Unwanted oxygen gas is vented to the atmosphere.

   Claim 2 A cooling system for mass transit underground systems that utilises liquid nitrogen as an indirect heat energy absorber by means of a heat exchanger interacting with normal air. Unwanted nitrogen gas is vented to the atmosphere.

   Claim 3 A cooling system as claimed in Claim I or 2 or Claims I and 2 whereby the cooled normal air is stored under pressure after suitable compression.

   Claim 4 A cooling system for mass transit underground systems whereby normal air cooled by whichever manner is stored under pressure after suitable compression.

   Claim 5 A cooling system where the stored and cooled normal air as claimed in Claim 3 or 4 is made available (for forward use) at a pressurised service head for mixing with another gas by means of a servo or computer controlled mixer valve.

   Claim 6 A cooling system as claimed in Claim S where the other gas is oxygen which is stored and made available (for forward use) at a pressurised oxygen service head and held at equal pressure to the cooled normal air pressurised service head and where the maximum possible (but variable) mixing ratio for the mixer valve is 10:1 where 10 is the air content and I is the oxygen content. The output cooled air from this mixer can therefore have an enriched oxygen content or no enriched oxygen at all (normal air) depending on the mixing valve setting.

   Claim 7 A cooling system as claimed in Claim 4 or 6 where the pressurised (enriched) and cooled output air is made available to air delivery (or dispensing) units mounted in static (track-side) positions along the track and platforms of the trains and whose air outputs are controlled by a track-side computer or by dynamically located (train mounted) infrared control signal sources. Claim

   A cooling system as claimed in Claim 7 where the said air delivery units can have a population density of up to 1 unit per 3 metres of track or platform length.

   Claim 9 A cooling system as claimed in Claim 8 where not more than 15% (or the number of units contained within the equivalent length of a train or transportation unit) of the air delivery units (for a given track/platform and in the service of any one train or transportation unit) are in use at any one time.

   Claim 10 A cooling system as claimed in Claim 9 where only the delivery units adjacent to a moving or stopped train (or transportation unit) are enabled for operation. (In the case of the moving train one can imagine the metaphor oJ'a surfer "riding a wave" off'the coast of'Hawaii where the "wave " in our case is a cushion of'cool air outputting from the delivery units adjacent to the train. i.e. As it moves along a train will receive cooled (enriched) air only from adjacent static delivery units with the delivery units not in the immediate vicinity of'the train shutting down as soon as the train passes try).

   Claimer A cooling system as claimed in Claim I or 2 where primarily the considerable energy required to bring about the transition of liquid oxygen (or nitrogen) to its gaseous state (latent heat of vapourisation) is put to use.

   Claim12 A cooling system as claimed in Claim 7 where the delivery unit output nozzle settings (determining quantity and geometry of air flow) are generated by instruction from the received infrared signals.

   Claiml3 A cooling system as claimed in Claim 7 where the train (transportation unit) are fitted with cooled air receiver units which are capable of receiving filtering and redirecting air flow (axial-to-radial fans and baffles) from the static delivery units.