Abstract:
The method apply charge of air to the cargo hold space of the underwater transportation ship or submarine, the pressure hull of cargo hold can be replaced by non-pressure type to achieve lower cost to transport dry cargo and solve strength/seal problems raised by cutting large hatch under water. By adopting the method, various new types of air-charge cargo submarine (ACS) and underwater construction can be designed. The dive depth of ACS is not large. The pressure and volume of the charged air are limited. Therefore the problems of safety, equipment and technology can be easily solved.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    There is no one or more prior filed copending nonprovisional applications. There is no similar U.S. patent was founded in searching of U.S. patent since 1974 to November 2001.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    There is no any federally sponsored research or development in this invention.  
         REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX  
         [0003]    It is not applicable in this case  
         BACKGROUND OF THE INVENTION  
         [0004]    In the late World War II, Germany used submarine transport military cargo due to the blockage from US and UK, and started designing underwater cargo ship for dry cargoes.  
           [0005]    After the War, many western countries have done lots of research and design about underwater transportation with nuclear power, including underwater oil tanker, mine and sand ship and dry cargo ship with loading of 20˜50 thousand ton. Some people in military field are interested in this kind design, and suppose the freeze won&#39;t make difference to underwater transportation. Some voyage can be shortened greatly if go through arctic pole sea area; While in war, hidden transportation can be achieved to make sure of smooth traffic route. Besides, high speed underwater oil tanker with nuclear power has greater advantages, compare with normal oil tanker with same speed and loading in storm.  
           [0006]    Another advantage of underwater oil tanker is: The hold is full of liquid oil which can&#39;t be compressed, therefore internal and external pressure the hold received can keep same in any depth under water, so the hold can be changed to non-pressure type. Its loading can increase by 30% compare with pressure hold with the same tonnage. There is no need of lift equipment while loading and unloading liquid oil. It is easy to open a small hole for vessel in modern submarine structure technology. So far, there is no any real underwater dry cargo transportation ship in the world.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0007]    The method apply air charge to the cargo hold space of the underwater transportation ship, so as to withstand the external water pressure, and to change the pressure direction of hold hull from external to internal. Therefore it is possible to avoid the hull instability under external pressure so that the pressure hull of cargo hold can be replaced by non-pressure type to solve the strength and seal problems raised by cutting large hatch under water. Meanwhile this method is efficient in reducing hull weight and increasing payload so as to solve the problems of the loading of large size military equipments and cargoes under-water and the cost of transportation.  
           [0008]    By adopting the method, various new types of air-charge cargo submarine (ACS) can be designed, such as carriers loading tanks, missiles, aircraft, diver, torpedo, dry cargoes, bulk cargoes, containers, and miner layer, supplier for submarine and oil/gas drilling vessels and warehouse etc.  
           [0009]    The dive depth of ACS is not large. The pressure and volume of the charged air are limited. Therefore the problems of safety, equipment and technology can be easily solved. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     Principle and Trait of ACS  
       [0010]    Charging the ACS hold With air to keep the same internal and external pressure or small pressure difference on hold under water. To balance internal air pressure with external water pressure, just like internal oil can support external water for underwater oil tanker. Here we name it as Air Supporting Pressure Principle (ASPP). Due to the application of ASPP, ACS has some traits as follows:  
         [0011]    1) The large size hull of ASC can be changed to light and thin non-pressure hull like that of underwater oil tanker. This way can reduce greatly the weight of the hull. Because the compressed air is dry and has hardly any weight, it only occupy all the spare space after loading cargoes, so the payload coefficient increase greatly.  
         [0012]    2) Due to the same internal and external pressure, hull of hold can be changed from pressure-resistant double hull to nonpressure-resistant single hull. Therefore it&#39;s possible to open large hatch and load large size cargo and military equipment. Because large hatch can be opened at the ASC bottom without getting water in, so some of special diver or submarine mother-ship, minelayer and exploration ship which will not be disturbed by storm can be designed.  
         [0013]    3) The hold has same internal and external pressure, or internal pressure is larger than external pressure, this way can avoid instability while the hull sustain external pressure, especially for thin-hull hold with large span. Therefore the hull strength can be improved.  
         [0014]    4) After air charging the hold, the energy can be reserved in the hold and can greatly slow down the coming water if the hold is damaged. While the damage occur at the hull bottom, the water can&#39;t enter no matter how the damage is. The anti-leak membrane can be used to prevent air leak in the damage of other parts where the internal air pressure is larger than external water pressure in the hold.  
       The Air-charge Method and Equipment of ACS  
       [0015]    The hold body of ACS is a kind of hull of steel or metal structure with interlayer of anti-leak membrane. The air-charged pressure depends on the depth of dive. The needed air pressure increase with the depth increasing, therefore can bring trouble to equipment and safety. It doesn&#39;t make sense if the depth is too small. There is need of selecting a suitable depth. The air-charge methods can be classified as follows:  
         [0016]    1) Air-charge Once on Water Surface (AOWS)  
         [0017]    Charging air after closing the hold with cargo while ACS is on the sea surface. Air can be offered with air compressor and high pressure air cylinder. The air pressure should be as large as the water pressure according to the supposed dive depth. The internal air pressure keep same while sailing. The difference of internal and external pressure made from the depth change can be supported by the hull. The internal pressure have to be supported by hull while ACS is on the sea surface. This method is simple and can make ACS up and down easily within regulated depth. But it&#39;s only for small depth range, in general, the ideal depth range is 25-50 m. According to this design, dive depth of 40 m is enough for normal ACS to avoid disturbance from sea surface, and can make sure of hidden transportation, and easily to sustain 5 atm internal pressure for a steel structural hold hull. In this case only  4  additional atm needs to be charged to the hold for 40 m depth. The pressure is smaller to that in car tyre so people can enter the hold without breath mask under this pressure. The oxygen pressure is low so it&#39;s easy to prevent air from burning. The hull has certain ability of resisting external pressure (such as 4 atm ), so the depth can be over 40 m ( will be 80 m ). For normal ACS, 40 m is the suitable depth with the most simple air-charge method of AOWS.  
         [0018]    2) Gradually Air-charge Under Water (GAUW)  
         [0019]    With the increase of dive depth, gradually charging air on ACS. The method is only for large depth and large hatch.  
         [0020]    3) Mix-air-charge (MA)  
         [0021]    Charging air on the water surface with certain amount. Gradually charging air under water with the increase of dive depth. For AOWS, the most simple method is offering air with air compressor and high pressure air cylinder on shore. Air-charge valve need to be installed on every hold a hull and directly charge air into the hold through pipe. While charging air in hold, there is a need to install high-pressure air source in hold such as high air-pressure cylinder. Because the pressure in high air-pressure cylinder can reach 200˜300 atm, for hold without high air-charge pressure, the amount of air cylinders is limited with small space and weight, so it&#39;s easy to install air cylinders in the hold. To keep the suitable air pressure in hold, the control of charging air and taking air out needs to be adjusted automatically by external pressure sensor in tie hold. Air-Compressed system is one of the important systems for modern submarine, its function is mainly for blowing water hold and supporting damaged hold. The air-charge equipment and technology that ACS needs have been solved.  
       The Structure, Power Equipment and General Layout of ACS  
       [0022]    1) Structure:  
         [0023]    Steel and metal structure is applied to whole hull of ACS. Pressure structure can be for habitation, power and control Add hold where always keep  1  atm for crew living and working. Non-pressure resistant structure can be for air-charge cargo hold and water hold. The hold takes most volume of the cargo ship loading and takes larger space with the increasing loading. Therefore the advantage coming from air-charge is larger. It was reported underwater nuclear power oil tanker with non-pressure resistant hold could have increased loading of 30% while the production cost reduce by 50%, comparing with underwater oil tanker with pressure hold in same tonnage. The hull weight is smaller than ship with same loading on water surface. Non-pressure resistant structure with ASPP in the design can have the same advantage.  
         [0024]    2) Power:  
         [0025]    Two types of power can be applied: diesel engine-electrical power and nuclear power. ACS with diesel engine-electrical power have to be charged electricity on sea surface, so the dive depth should not be large. Therefore charged air pressure is not large. The hold hull support internal pressure while it&#39;s on sea surface and can be up and down within the designed depth. For ACS with nuclear power, there is no depth limitation.  
         [0026]    3) General Layout:  
         [0027]    As to general layout of ACS, the non-pressure structure hull include the cargo hold, hold alleyway and water ballast cabin, they occupy the most part of the ACS. The rest cabins, such as personnel, power, control, transition cabins and personnel alleyway should all be 1 atm pressure cabins with pressure resistant structure, they usually in the back part of the ACS except the command cabin. Personnel alleyway for connect with the command cabin, living, power and control cabins. Observation window facing cargo hold and transition cabin are in the alleyway for monitoring and check-up, transition cabin pressure can be changed for crew in and out of the cargo hold. Some important pipe, communication and electricity line are also in the alleyway for check-up and service. The hold gate can be on the ship head or bottom of the ACS, especially right for loading large size equipment, such as tank, vessel, missile, aircraft, diver, torpedo, mine and other equipment etc.  
       The Safety of Air-charge Hold  
       [0028]    1) Safely Charging Air, Exhaust Air Out and Preventing Air from Leaking  
         [0029]    While charging air on sea surface, there is need of preventing air from leaking. While gradually charging air under water, there is need of charging air to hold with automatic sensor control valve for adding pressure, or exhaust air out of hold to reduce pressure. For over water depth of 100 meters, oxygen pressure can increase due to the charge of compressed air. There is need of charging non-oxygen gas to prevent cargo hold from burning, usually charging non-oxygen air, nitrogen or CO 2 . This time, personnel have to wear mask while being in cargo hold.  
         [0030]    Normal deflation is before unloading. The most simple method is to exhaust air out of hold under water or on sea surface. Normal deflation needs to be controlled to prevent deflation from taking place outside of the exhaust valve. Otherwise the non-controlled air can cause personnel hurt and equipment damage with certain energy.  
         [0031]    ACS permits no air leak under water. Otherwise can reduce the hull strength on the part of leak and cause accident. On the other hand, that can lose concealment while in war. Underwater leak usually take place at some joining gaps and little hole while internal pressure is larger than external pressure, namely sailing in small depth. Leak can be prevented with interlayer of anti-leak membrane on the internal wall of cargo hold and cargo gate, the membrane function is just like that of inner tyre of car.  
         [0032]    2) Monitor System  
         [0033]    Usually the crew live and work in normal pressure (1 atm) cabin instead of being in cargo hold with high pressure, monitor system has to be installed in normal cabin for monitoring accident caused from burning, water leak and air leak in cargo hold. The monitor system consists of watching window, sensor meters, stakeout TV system and communication/command system.  
         [0034]    3) Prevent Burning  
         [0035]    For cargo hold with compressed air, there is need of charging air of 4 additional atm while sailing at the depth of 40 meters. At this point oxygen pressure is lower than 1 atm. Though this oxygen pressure don&#39;t cause burn easily, safety rules of pressure cabin can be stipulated for the air-charge hold. For the cargo which can burn easily, steps should be taken to prevent burning. There are needs of certain types and amount of fire extinguisher in and out of the cargo hold. If charging non-oxygen air in the cargo hold, the problem of burn can be solved.  
         [0036]    4) Requirement of Cargo  
         [0037]    All cargoes have to be able to sustain the external air charge pressure. That is out of question for normal dry and bulk cargo. Those industry and military equipment without pressure-resisting test before need to be tested and taken steps for those parts, such as adding pressure hull for non-pressure meter, charging liquid or full filling the fuel box of engine.  
       Safety of the Crew  
       [0038]    The crew live in normal pressure (1 atm) cabin in voyage and only enter cargo hold while accident happen. Therefore personnel will face problems in high pressure. Dive medical safety in high pressure can be involved. Therefore the crew have to take dive and dive medical training to easily operate in high pressure and decompression according to rules while getting out. Transition cabin is between normal pressure cabin and cargo hold for personnel. Normal people can enter high pressure environment at increase rate of 4 atm per minute so personnel can enter high pressure hold rapidly from cabin of 1 atm.  
         [0039]    Charging air with additional 4 atm in cargo hold while ACS is in depth of 40 meters the crew can stay 24 safety hours taking directly normal breath. The time is enough for personnel to stay in cargo and deal with trouble.  
         [0040]    Personnel have to be decompressed after getting out of cargo hold due to staying in high pressure for a while to prevent decompression disease and lung damage. The decompression takes place in transition cabin. The decompression time depends on pressure, time length of staying in high pressure and gas kind in cargo hold. It usually takes 10˜20 minutes to check and deal with the trouble, so it only takes several minutes for decompression with rapid decompression method. Decompression have to be carried out strictly according rules and plan stipulated in advance. Therefore personnel can be easily decompressed and have safety guarantee.  
         [0041]    Air pressure can be over 7 atm in cargo hold while the dive depth is over 60 meters. Personnel can&#39;t breathe the compression air and have to wear breath mask with helium-oxygen or nitrogen-oxygen. The decompression time have to last long. Currently human can take breath in helium oxygen with 61 atm, which is equal to water pressure of 600 meter. Therefore personnel can have big possibility to operate in high pressure environment.