Patent Publication Number: US-10780962-B2

Title: Ventilation system

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     The present application is a U.S. national stage application under 35 U.S.C. § 371 of PCT Application No. KT/IB2016/056773, filed Nov. 10, 2016. The disclosure of the aforementioned priority application is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a system for emergency ventilation of an underwater environment, a method for the emergency ventilation of an underwater environment and a capsule for the emergency ventilation of an underwater environment. 
     This invention also relates to the use of the system and/or the capsule for an emergency recovery intervention of underwater environment. 
     Context of the Invention 
     In the deep diving systems sector, when it is necessary to recover a damaged underwater environment (for example a submarine and/or a welding habitat), a rescue vessel (or a platform) is usually used equipped with a large compressed air storage system. The underwater environment is connected to two ducts, one is for transferring the pressurized air from this storage system to the underwater environment, and the other to bring the exhaust air back to the surface. The air that is pushed must be with high pressure, since it has to reach the underwater environment and come back to surface (to facilitate this air movement, there are some pumps at the end of the second duct). 
     The recovery activities as described above, have certain disadvantages including: the necessity to have huge and expensive devices to direct the pressurized air and (most of all) to recovery and allow air to escape in surface; and a relevant pressure increase inside the underwater environment with some health risks for the operators inside the underwater environment and the necessity to keep them in a decompression chamber in way to reduce embolism risks, once they are recovered. 
     The aim of the present invention is to provide an emergency ventilation system of an underwater environment, a method for the emergency ventilation of an underwater environment and a capsule for the emergency ventilation of an underwater environment and a use of the system and/or of the capsule for an emergency recovery, which make it possible to overcome, at least partially, the inconvenience of this type of activity and is at the same time cost-effective and easy to realize. 
     SUMMARY 
     According to the present invention, an emergency ventilation system for an underwater environment, a method for the emergency ventilation of an underwater environment, a capsule for the emergency ventilation of an underwater environment and a use of the system and/or the capsule for an emergency recovery is provided, as recited in the independent claims below, and, preferably, in any one of the claims depending directly or indirectly on the aforementioned independent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE PICTURES 
       The invention is hereinafter described with reference to the accompanying drawings, which describe a non-limiting embodiment, wherein: 
         FIG. 1  is a lateral and schematic view of a system according to this invention; and 
         FIG. 2  is a lateral and schematic view, where some internal details of a part of the system shown in  FIG. 1  are depicted. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1, 1  indicates a system for the emergency ventilation of an underwater environment  2  (dry) as a whole. According to some non-limiting examples, the underwater environment  2  is a submarine and/or a welding habitat. 
     The system  1  comprises a supply device  3  for providing a gas containing oxygen, in particular air; a capsule  4  adapted to be immersed in water (in particular, to a depth of at least 60 meters—below the surface  5 ); a duct  6  to fluidically connect the power supply device  3  to the capsule  4  so that the capsule  4  uploads the gas coming from the supply device  3 . 
     Advantageously but not necessarily, the capsule  4  is adapted to be immersed in water to a depth of at least 100 meters (below the surface  5  of water). 
     The system  1  comprises also a duct  7  to fluidically connect the capsule  4  to the underwater environment  2  so as to allow the passage of gas from the capsule  4  to the underwater environment  2  itself; a duct  8  to fluidically connect the underwater environment  2  to the capsule  4  so that it allows the passage of the gas from the underwater environment  2  to the capsule  4 ; and one compressor  9  for the exhaust of the gas arrived inside the capsule  4  through the duct  8  from the underwater environment  2  into the water at a depth of at least 60 meters (under the surface  5  of the water itself). In particular, the compressor  9  is adapted to unload the gas inside water at a depth of at least 100 meters (under the surface  5  of the water itself). The compressor  9  is fluidically connected to duct  8 . 
     In particular, the capsule  4  includes the compressor  9 . 
     More precisely, the duct  6  is extended from the supplying device  3  to the capsule  4 ; the duct  7  and  8  protrude from capsule  4  and are arranged to bond at the underwater environment  2 . 
     Advantageously but not necessarily, the supplying device  3  is suitable to be (and during the use is) placed outside of the water in an environment substantially dry. 
     According to some not limiting embodiments, the supplying device  3  is designed to supply gas to the capsule  4  at a pressure that is higher than atmospheric pressure (for example, at a pressure up to 3 bar). 
     Advantageously but not necessarily, the system  1  (more precisely, the capsule  4 ) comprises an adjustment device  10  to adjust the pressure of the gas that is supplied to the underwater environment  2 . More particularly, the adjustment device  10  is designed to adjust the pressure of the gas inside the duct  7 , so that the gas reaches the underwater environment  2  at a pressure that is lower than a first given pressure (in some cases of 3 bar absolute—corresponding to 30 5  Pa). More precisely, the adjustment device  10  is suitable to adjust the pressure of the gas inside the duct  7 , so that the gas reaches the underwater environment  2  at a pressure that is lower than a first given pressure of 2 bar—corresponding to 205 Pa. 
     In particular, higher-pressure levels, up to 6 bar, may be necessary to maintain the ventilation flow whenever pressure increases take place due to failures inside the underwater environment  2 . 
     According to some embodiments, the adjustment device  10  comprises (is) a valve (in some cases a ball valve) and/or a membrane mechanism. Due to the adjustment device  10  the risk of excessive pressure increase inside the underwater environment  2  is reduced. Advantageously but not necessarily, the system  1  (more precisely, the capsule  4 ) comprises a control unit  11 . 
     In some cases, the control unit  11  is designed to adjust the operation of at least one between the supplying device  3  and compressor  9  (and/or the heat exchanger  9 ′), so as to keep the concentration of the carbon dioxide (and/or other specific gases) and/or oxygen (and/or the temperature) (and/or the ventilation) inside the underwater environment  2  within a given interval (to allow the air inside the underwater environment  2  to be breathable for the operators located inside it). 
     For example, where an oxygen concentration which may be considered too low is detected, the control unit  11  will operate the supplying device  3  and the compressor  9  in such a way to increase the air flow (coming from the surface) through the capsule  4 . 
     In some cases, the system  1  comprises a sensor  12  for the detection of the carbon dioxide and/or oxygen concentration inside the gas coming from the underwater environment  2  (particularly, through the duct  8 ). 
     In addition, or alternatively, the system  1  comprises a connection  13  for a detection system, which is arranged in the underwater environment  2  and is designed to detect the concentration of carbon dioxide (and/or of other specific gases) and/or oxygen (and/or temperature) in the underwater environment  2  itself. In particular, the control unit  11  is connected to the sensor  12  and/or to the connection  13  and is adapted to adjust the actuation of at least one of the power supply device  3  and the compressor  9  (and/or the heat exchanger  9 ′) according to what is detected by the sensor  12  and/or by the detection system (of the underwater environment  2 ), respectively. 
     Advantageously but not necessarily, the system  1  (in particular, the capsule  4 ) includes a heat exchanger  9  in order to heat the gases to be fed in the underwater environment  2  through the duct  7 . In particular, the heat exchanger  9 ′ is connected to the compressor  9  so that the heat produced by the compressor  9  itself can be used. 
     According to some non-limiting embodiments, the system  1  (in particular, the capsule  4 ) comprises an adjusting device  14  to allow the passage of gas from the underwater environment  2  to the compressor  9  through the duct  8  when the pressure in the duct  8  is higher than a reference pressure (in particular, 1 bar absolute, more particularly, not more than 1 bar in addition to the original pressure of the underwater environment  2 ). More precisely, the adjusting device  14  comprises (is) a valve (in some cases a ball valve) and/or a diaphragm mechanism. Thanks to the adjusting device  14  it reduces the risk that the pressure inside the underwater environment  2  decreases excessively. 
     According to some non-limiting embodiments, the system  1  (in particular, the capsule  4 ) comprises a tank  15  for fluidically connecting the duct  8  and the compressor  9 . In particular, the duct  8  goes from the reservoir  15  to the underwater environment  2 . 
     More precisely, the tank  15  fluidically connects (is located between) the adjusting device  14  and the compressor  9 . 
     Advantageously but not necessarily, the control unit  11  is adapted to activate the compressor  9  so as to maintain the pressure inside the tank  15  in a given range, in particular compatible with the performance of the compressor  9  (more specifically, from 1 bar to 2 bar absolute). In particular, the capsule  4  comprises a pressure sensor  16  for measuring the pressure inside the tank  15 . More particularly, the control unit  11  activates the compressor  9  as a function what is detected by the pressure sensor  16 . 
     In some cases (such as the one illustrated in  FIG. 2 ), a valve (ball valve) is located between the sensor  16  and the tank  15 . 
     Typically but not necessarily, the system  1  includes a vessel or a platform  17 , on which the power supply device  3  is located. In particular, the power supply device  3  comprises a pump (and a tank/gas storage) which enables the gas (air) to be pushed from above the water surface  5  to the capsule  4 . 
     According to some non-limiting embodiments, the system  1  also includes an electrical connection  18  for supplying electrical energy to the capsule  4  (and its components) from outside (in particular, from the platform  17 ). More precisely, the electrical connection  18  is adapted to supply the control unit  11 , the compressor  9  and the sensors  12  and  16 . 
     Advantageously but not necessarily, the system  1  also comprises a link  19  to allow the transfer of information between the boat or platform  17  and the control unit  11 . 
     According to some non-limiting embodiments, the system  1  comprises a ballast  20 , which, in particular, maintains the capsule  4  at the required depth (maintaining its own stability in water). 
     Advantageously but not necessarily, system  1  includes an auxiliary umbilical cable  21 , which is adapted to bear the weight of the capsule  4  (and possibly also the ballast  20 ) in the air and the related dynamic loads during the launching. In particular, the electrical connection  18 , the link  19  and in the duct  6  are part of or connected to (inserted into) the umbilical cable  21 . More particularly, the umbilical cable  21  connects the vessel or platform  17  to the capsule  4 . 
     According to some non-limiting embodiments, the system  1  also includes a launch and recovery unit  22 , which is suitable for moving (for example, bring it in water and/or lift it) the capsule  4  by acting on the umbilical cable  21 . 
     According to some non-limiting embodiments, the capsule  4  includes an exhaust outlet  23 , adapted to allow the exit of the gas (exhausted) in the water from the capsule  4 . The compressor  9  is designed to convey the gas through the exhaust outlet  23 . 
     Advantageously but not necessarily, a one-way valve  24  (to prevent water coming from the exhaust outlet  23  reaches the compressor  9 ) is located between the exhaust outlet  23  and the compressor  9 . According to some non-limiting embodiments, the capsule  4  comprises a filter  25  also, which is located between the duct  8  (more specifically, the adjusting device  10 ; even more precisely, the tank  15 ) and the compressor  9 . The filter  25  helps to improve the mechanical protection of the compressor  9 . 
     According to some non-limiting embodiments, the capsule  4  also comprises a vacuum breaker valve  26 , which is located downstream of the underwater environment  2  in order to avoid creating an excessive depression in the underwater environment  2  itself. In particular, the vacuum breaker valve  26  is located between the duct  8  and the compressor  9 . 
     Advantageously but not necessarily, a one-way valve  27  which allows the passage of gas only from the duct  6  to the capsule  4  and not vice versa is also provided. More precisely, the one-way valve  27  is placed between the duct  6  and the adjusting device  10 . 
     In particular, the capsule  4  comprises a casing  28  (typically of metal), which is resistant to the external pressure at high depth and encloses the various further components of the capsule  4 , for example: the adjustment devices  10  and  14 , the unit control  11 , the sensors  12  and  16  and the tank  15  (and, possibly, the one-way valves  24  and  27 , the vacuum breaker valve  26  and the filter  25 ). 
     According to some embodiments not illustrated and not limitative, the capsule  4  can be composed of two or more separate groups each one provided with its own casing  28 . 
     In some cases, in order to improve maintenance activities, a vent  29  is also provided to allow the correct emptying of the tank  15 . In particular, a valve (ball valve) is located between the tank  15  and the vent  29 . 
     In operation, after the launch from the surface, the capsule  4  reaches the depth required (in particular, a depth similar to the underwater environment depth  2  where it operates). 
     At this point, the capsule  4  (more precisely, the ducts  7  and  8 —and potentially the connection  13 ) is connected to the underwater environment  2 , for example by means of a ROV, through an underwater environment  2  emergency connection  30 . 
     At this point, the power supply device  3  and the compressor  9  are actuated to allow the supply of gas (fresh air) from above the surface  5  to the capsule  4  and from the capsule  4  to the underwater environment  2 , and the gas (exhaust air) from the underwater environment  2  to the compressor  9  and from the compressor  9  to the water (through the exhaust outlet  23 ). 
     Please note that the system  1  in accordance with the present invention has considerable advantages over known systems. Among these, we emphasize that the system  1  according to the present invention is relatively simple and cost-effective (especially because it does not require any equipment to transfer and vent the exhaust air to the surface) and less harmful and dangerous for the health of the operators present in the underwater environment  2  (you can keep relatively low pressures within the underwater environment  2 ). 
     In particular, in accordance with an additional aspect of this invention, a method for the emergency ventilation of an underwater environment  2  (dry) is provided with a system as described above, and comprising: a first supplying step, during which the gas is fed from the supply device  3  to the capsule  4  immersed in water at a pressure higher than the atmospheric pressure; a second supplying step, during which the gas is conveyed from the capsule  4  immersed in water to the underwater environment  2  through the duct  7 ; a recovery step, which is at least partly subsequent to the second supplying step and during which the gas is brought from the underwater environment  2  to the capsule  4  immersed in the water through the duct  8 ; and a draining step, which is at least partially after the recovery step and during which the gas coming from the underwater environment  2  and arriving to the capsule  4 , which is immersed in the water, is discharged into the water. 
     Advantageously but not necessarily, during the first and the second supplying steps, the recovery step and the draining step, the capsule  4  is maintained immersed in water at a distance of at most 40 meters from the underwater environment  2 . 
     Typically, the underwater environment  2  is at a depth of 60 (in particular, from 100) to 700 meters (from the surface  5 ). 
     According to some non-limiting embodiments, during the supply step, the gas pressure coming from the supply device  3  is maintained within a given range in the area of the capsule  4 , in particular proportional to the depth of intervention (more particularly between 2 bar absolute and a higher value due to the increase in pressure that makes it possible to overcome the pressure losses of the flow line, according to the depth of intervention—70 bar absolute for example). 
     According to some non-limiting embodiments, the method also comprises a pressure regulation step, during which, in the area of the capsule  4 , the gas pressure (from the capsule  4  itself) towards the underwater environment  2  is maintained (flow rate) within a given range. 
     In particular, during the regulation step, the gas pressure (coming from the supplying device  3 ) is reduced. 
     According to some non-limiting embodiments (in other words), during the second supply step, the gas is conveyed from the capsule  4 , which is immersed in water, to the underwater environment  2  at a pressure within the given range. 
     In particular, the pressure of the gas conveyed from the capsule  4  to the underwater environment  2  during the second supply step is less than the pressure of the gas supplied to the capsule  4  during the first supply step. 
     In particular, the given range is from 1 bar absolute to 3 bar absolute (more particularly, to 2 bar). 
     In particular, in accordance with further aspect of this invention, a capsule  4  as described above is provided. 
     In accordance with a further aspect of this invention, a use of the system  1  and/or of the capsule  4  for a emergency recovery intervention of an underwater environment  2  is provided (such an underwater environment  2  is as described above). In particular, the use provides to follow a method as described above.