GB1602095A - Air conditioning apparatus in surface vehicles - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO AIR CONDITIONING APPARATUS IN SURFACE VEHICLES (71) We, BRITISH AEROSPACE PUBLIC LIMITED COMPANY, a British Company organised under British Aerospace (Nominated Company) order 1980 and British Aerospace (Appointed Day) Order 1980, of 100 Pall Mall, London, SWIY 5HR do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to air conditioning apparatus in surface vehicles.

In large enclosures such as buildings, ships and railway trains, where space is available and where weight is relatively unimportant, it is common practice to use piant having its own power source and the most common type is that in which a gas such as Freon (Registered Trade Mark) is pumped around a system, including a heat exchanger, similar to that of a refrigerator and the air is then blown through the heat exchanger to cool it.

An alternative system, used in aircraft powered by gas turbine engines which have an ample reserve of power and a compressor as part of each power unit, is to take a tapping of compressed air from a gas turbine compressor, pass it through a heat exchanger to remove heat and then allow it to expand with further loss of heat.

It has recently become recognised that such latter systems can advantageously be employed for armoured fighting vehicles, whereby the crew are enabled to make more effective use of the vehicle. For existing vehicles a known system designed and produced by Plessey Aerospace and Hawker Siddeley Dynamics Limited takes the form of an integral lightweight gas turbine-driven power pack providing a supply of conditioned air and also electrical power. Such a power pack can be fitted to a vehicle and form part of its equipment or it can be used externally to provide air and electrical power to a group of vehicles in "harbour" In such known systems the conditioned air supplied from the compressor cools the vehicle cockpit and is then discharged overboard.

According to the present invention, there is provided air-conditioning apparatus in a surface vehicle comprising an airrecirculating system including a two-stage compressor, a heat exchanger cooled in use by a flow of atmospheric air from outside the vehicle, and an expansion machine driving the second stage of the compressor, the first compressor stage being dnven. by an external power input, the recirculating air being drawn from the vehicle compartment to be air-conditioned, compressed in the two compressor stages, cooled after compressiop in the heat exchanger and then being expanded and further cooled in the expansion machine before being returned to the vehicle compartment, the recirculating system further including molecular biological and chemical filter means for purifying the recirculated air.

The invention thus makes more effective use of power by recycling the air through the system, the excess heat from the system being removed by a heat exchanger cooled by air external to the air-conditioning system.

The noxious or harmful substances are removed from the recycled air by employing a molecular biological and chemical filter means to destroy or remove such substances before the air re-enters the vehicle compartment.

Because the power requirement of the system is reduced it can be smaller than hitherto, thereby making it easier to instal and reducing manufacturing and operating costs.

One embodiment of the invention will now be described by way of example and with reference to the accompanying drawing, which is a diagrammatic representation of an air conditioning system in an armoured fighting vehicle.

In the system shown in the drawing, a power source at 1, which may be either a self-contained power unit or a shaft driven from a main engine of the vehicle, is coupled to drive a compressor 2. Air entering the compressor 2 from the vehicle cockpit 3 is compressed and fed to a second stage compressor 4 from where it passes through a heat exchanger 5 that is cooled by a flow of external atmospheric air which is induced by a fan 9. The temperature of the compressed air is thereby reduced, and this air then serves to drive a turbine 6 to which the compressor 4 is mechanically coupled.

The air leaving the turbine 6 at relatively low temperature then passes through a water extractor 7 and molecular biological and chemical filter means 8 after which it returns to the vehicle cockpit 3.

To provide adjustment of flow whereby the system is made flexible, a 2-way valve 10 is provided in the compressed air duct between the first and second stage compressor 2, 4, which valve allows air in excess of requirements to be off-loaded. For adjusting the temperature of the vehicle cockpit, a temperature control valve 11 is provided which is situated in a bypass in parallel with the heat exchanger 5 so that it regulates the proportion of the compressed air flow that passes through the heat exchanger.

WHAT WE CLAIM IS:- 1. Air-conditioning apparatus in a surface vehicle comprising an air-recirculating system including a two-stage compressor, a heat exchanger cooled in use by a flow of atmospheric air from outside the vehicle, and an expansion machine driving the second stage of the compressor, the first compressor stage being driven by an external power input, the recirculating air being drawn from the vehicle compartment to be air-conditioned, compressed in the two compressor stages, cooled after compression in the heat exchanger and then being expanded and further cooled in the expansion machine before being returned to the vehicle compartment, the recirculating system further including molecular biological and chemical filter means for purifying the recirculated air.

2. Apparatus according to claim 1, wherein an air-exhausting valve is provided between the two compressor stages which valve is adjustable for exhausting a variable proportion of the compressed air delivered by the first stage.

3. Apparatus according to claim 1 or claim 2, wherein the heat exchanger has a bypass and a temperature control valve is situated in the bypass and is adjustable to vary the proportion of the compressed air that passes through the heat exchanger.

4. Apparatus according to any one of the preceding claims, wherein the air exhausting from the expansion machine is passed through a water separator in addition to the biological and chemical filter means before being returned to the vehicle compartment.

5. An air conditioning apparatus in an armoured fighting vehicle, substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. with reference to the accompanying drawing, which is a diagrammatic representation of an air conditioning system in an armoured fighting vehicle. In the system shown in the drawing, a power source at 1, which may be either a self-contained power unit or a shaft driven from a main engine of the vehicle, is coupled to drive a compressor 2. Air entering the compressor 2 from the vehicle cockpit 3 is compressed and fed to a second stage compressor 4 from where it passes through a heat exchanger 5 that is cooled by a flow of external atmospheric air which is induced by a fan 9. The temperature of the compressed air is thereby reduced, and this air then serves to drive a turbine 6 to which the compressor 4 is mechanically coupled. The air leaving the turbine 6 at relatively low temperature then passes through a water extractor 7 and molecular biological and chemical filter means 8 after which it returns to the vehicle cockpit 3. To provide adjustment of flow whereby the system is made flexible, a 2-way valve 10 is provided in the compressed air duct between the first and second stage compressor 2, 4, which valve allows air in excess of requirements to be off-loaded. For adjusting the temperature of the vehicle cockpit, a temperature control valve 11 is provided which is situated in a bypass in parallel with the heat exchanger 5 so that it regulates the proportion of the compressed air flow that passes through the heat exchanger. WHAT WE CLAIM IS:-

1. Air-conditioning apparatus in a surface vehicle comprising an air-recirculating system including a two-stage compressor, a heat exchanger cooled in use by a flow of atmospheric air from outside the vehicle, and an expansion machine driving the second stage of the compressor, the first compressor stage being driven by an external power input, the recirculating air being drawn from the vehicle compartment to be air-conditioned, compressed in the two compressor stages, cooled after compression in the heat exchanger and then being expanded and further cooled in the expansion machine before being returned to the vehicle compartment, the recirculating system further including molecular biological and chemical filter means for purifying the recirculated air.

2. Apparatus according to claim 1, wherein an air-exhausting valve is provided between the two compressor stages which valve is adjustable for exhausting a variable proportion of the compressed air delivered by the first stage.

3. Apparatus according to claim 1 or claim 2, wherein the heat exchanger has a bypass and a temperature control valve is situated in the bypass and is adjustable to vary the proportion of the compressed air that passes through the heat exchanger.

4. Apparatus according to any one of the preceding claims, wherein the air exhausting from the expansion machine is passed through a water separator in addition to the biological and chemical filter means before being returned to the vehicle compartment.

5. An air conditioning apparatus in an armoured fighting vehicle, substantially as hereinbefore described with reference to the accompanying drawing.