The invention concerns a device for supplying air and operating means to a vessel located at a great depth and a device for balancing a vessel in water, e.g. a salvage dock, barge, submarine, pump stations, subsea devices etc.
The ascent and descent of a vessel at great depths entails major problems with regard to air supply. Due to the considerable difference in pressure between the surface and the depth concerned, it will be necessary to bring along large quantities of air. When manoeuvering a vessel in water it can be difficult to achieve a stable descent and ascent, due, amongst other factors, to possible bias, erratic air supply, etc.
Thus it is desirable to provide a device for balancing and positioning of vessels in water which, e.g., are biased and to provide a device for further transport of air down to the depth concerned.
The object of the invention is therefore to provide a device for supply of air and operating means to a vessel, wherein the device enables the air supply to be replenished, thus avoiding the transport of large quantities of air on board the vessel. A further object, especially during the employment of such a method, is to provide a device for balancing, submerging and positioning of such a vessel in water.
The object of the present invention is achieved by a device according to claim 1. A special object of the device is obtained when a compressed air supply is provided which is connected to a service tank with an overpressure chamber. Further features are obtained by means of the sub-claims.
The invention will now be described in more detail by means of an embodiment which is illustrated by means of the drawing. The drawing comprises the following:
Fig. 1 of the drawing shows a pump station 1 with a ballast chamber 2. Through the pump station 1 there are passed means 3, e.g. connection elements for cables or air input 16. The pump station 1 comprises an electrical compressor 4, which is controlled by an adjustable pressure sensor 8 which maintains a desired exit pressure 12, e.g. at 500m, of approximately 55 bar, i.e. at overpressure. There are further provided propulsion means 5, 9, e.g. electrical motors for, amongst other things, operation of the compressor 4 and cooling devices 13, 14. A pressure controller 6 is connected to the compressor 4 for pressure control and the adjustable pressure sensor 8 is further connected to the pressure controller 6. For manoeuvering, the pump station 1 is equipped with hydraulically driven propellers 17, operated by a hydraulic pump 7 which is connected to an oil cooler 14. Inside the pump station 1 there is provided an overpressure chamber 11 with a two-way valve 10. The pump station 1 is further equipped with an air cooler 13 and control means in the form of a control centre 15 with transmitting and receiving devices 18.
Fig. 2 illustrates a compressed air supply in the form of an air storage bottle 19 with a pressure-actuated bottom 20 consisting of an orifice 21 for pressure equalization with a grid 22 and a first end cap 23 which is threaded on the air storage bottle 19. At the other end there is provided a second end cap 24 with an air inlet 25. Inside the air storage bottle 19 there is provided a moveable bottom 20, with packing rings 26, which can be moved between the first end cap 23 and an end stop 27.
Fig. 3 illustrates an example of the use of pump stations 1 between a surface vessel and a vessel in water. These pump stations are provided spaced at a specified distance apart, e.g. 500 metres.
Fig. 4 illustrates the device for balancing a vessel in water consisting of a compressed air supply 29, e.g. according to fig. 2, or air supply from the surface 39, possibly via pump stations 1, connected to a service tank 30 with an overpressure chamber 31, where between the pressure chamber 31 and the service tank 30 there is provided a two-way valve 32. There is further provided a compressor 33 between the compressed air supply 29 or surface air 39 and the service tank 30. Buoyancy tank(s) 28 with overpressure sensors 34 are connected to the device. These are designed to control the pressure difference between an internal pressure in the buoyancy tank(s) 28 and an ambient water pressure. The compressor 33 is provided in such a manner that it maintains the pressure in the service tank 30. In the buoyancy tank 28 there is provided a bottom valve 35 which is opened during both ascent and descent and the pressure sensor 34 also controls a pressure relief valve 36 during ascent. The pressure sensor 34 reads and determines the pressure difference between the buoyancy tanks 28 and an ambient water pressure. The pressure difference can be adjusted continuously in order to achieve the desiired rate of descent or ascent. Furthermore pressure sensors 34 are installed at the same height on all the buoyancy tanks to enable the vessel to be trimmed in the desired or a horizontal position. Water-sensitive equipment such as electrical motors, cameras, relays and contacts, etc. are installed in the overpressure chamber 31 with an automatic control, by means of the two-way valve 32, of a predetermined overpressure regardless of depth. There are further provided air supply valves 37, which are connected to the air supply from the surface or the pump station, on both sides of the service tank 30, and check valves 38 are provided between the air supply 29 and the service tank 30. During descent and ascent the compressor 33 will automatically upgrade the air supply 29 and keep the volume of air in the air supply 29 constant in relation to the ambient water pressure.
The method for supply of air and operating means to a vessel which is located at a great depth is implemented by providing one or more pump stations at suitable distances between the surface and the vessel. The pump station(s) 1 with, e.g., an eliptical shape, comprises an electrically operated compressor 4, which is controlled by the adjustable pressure sensor 8 which keeps the exit pressure 12 at approximately 55 bar overpressure. The pump station 1 is equipped as an overpressure chamber, and is controlled by the two-way valve 10 and maintains a predetermined overpressure in relation to the ambient pressure. For manoeuvering, the pump station 1 is equipped with hydraulically operated propellers 17. These are operated by an electrically-driven hydraulic pump 7, which is cooled by an oil cooler 13. The overpressure chamber 11 is equipped with an air cooler 12. For positioning, the pump station 1 is equipped with a control centre 15 and signal transmitter and receiver 18. The compressed air supply constitutes a reserve supply in the event of faults in the air supply from the surface or the pump station.
The pressure supply is not limited to the air storage bottle embodiment. It will also be possible to employ other forms of compressed air supply. Conversely, it will also be possible to employ the air storage bottle embodiment in other connections, such as a gas supply.
A device, e.g. in the form of a salvage dock, can control the nearest pump station, which in turn controls the next, an so on up to the surface. The positioning system will be capable of positioning both the salvage dock and pump stations in a vertical position over the salvage object. A salvage dock which can be used in connection with the invention is described in Norwegian patent application no. 92 1774.
The device according to the invention can be equipped with automatically controlled ascent, if any faults should arise in the signals from the surface. It can also be remotely controlled from the surface or from a mini-submarine.