Patent Publication Number: US-2018031005-A1

Title: Engineered tissue substitute system

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to a device, system and method for subsea piston accumulators utilized with blowout preventers in oil and gas well operations. More particularly, the present invention provides an improved bladder having a dispersion tube to ensure the hydraulic fluid stored in the bladder is communicated into the seawater chamber of the subsea piston accumulators as desired. 
     2. Description of the Prior Art 
     As known in the art, a blowout preventer is a large, specialized valve or similar mechanical device, usually installed redundantly in stacks, used to seal, control and monitor oil and gas wells. Blowout preventers were developed to cope with extreme erratic pressures and uncontrolled flow, often referred to as a formation kick, emanating from a well reservoir during drilling. Kicks can lead to a potentially catastrophic event known as a blowout. In addition to controlling the downhole pressure occurring in the drilled hole and the flow of oil and gas, blowout preventers are intended to prevent tubing such as drill pipe and well casing, tools and drilling fluid from being blown out of the wellbore when a blowout threatens. 
     A typical subsea deep-water blowout preventer system includes hydraulic accumulators module that maintains the hydraulic fluid pressures needed to actuate valves on the blow out preventer. A subsea accumulator stores hydraulic fluid under pressure and must release the hydraulic fluid on demand to provide fast closure of the preventers and for cycling all critical components. The fluid to be pressurized is typically an oil-based product or a water based product with added lubricity and corrosion protection. Accumulators with a piston typically have a piston sliding up and down a seal bore to separate the fluid from the gas. 
     It is also known that a depth compensated piston accumulator must maintain a constant working fluid pressure in the working fluid chamber at any depth. At the surface, the nitrogen chamber is charged to a specific pressure, which exerts a force on top of the piston, which in turn pressurizes the working hydraulic fluid on the other side of the piston. As the accumulator is lowered deeper into the ocean, the ambient seawater pressure squeezes the hydraulic fluid in the bladder to the same pressure. This seawater pressure from the bladder is exerted on top of the piston in the seawater chamber. Essentially, all of the pressure force that is lost from the nitrogen due to the increased water pressure in very deep water is regained by directing that ambient pressure to the seawater chamber. 
     Furthermore, when the working fluid chamber is full with the working fluid, the seawater chamber hydraulic fluid is stored in the bladder. In this situation, the bladder is completely full. When the working fluid is expelled from the working fluid chamber, the seawater chamber is filled with the hydraulic fluid from the bladder. It is desirable that the seawater chamber fill completely, which is a function dependent on the bladder performance. 
     The bladder must communicate fluid to the seawater chamber as needed as well as receive fluid from the seawater chamber. A known problem is ensuring that the hydraulic fluid is able to get into the seawater chamber from the bladder. As the piston moves and the volume in the seawater chamber increases, the fluid from the bladder is sucked into the seawater chamber. If fluid is not transferred, a vacuum will be pulled into the chamber and the depth compensation function will fail. 
     It is known that bladders are typically made for a nylon material and also provided with a liner. It is also known in the prior art devices for the liner to collapse inside the bladder when fluid is being sucked into the seawater chamber. This may impede the flow of the fluid and prevent the accumulator from working properly and or as efficiently. 
     Thus, there is a need for an apparatus, process and or system that provides a functioning bladder system for use with a subsea piston accumulator. It is desirable to fill these needs with reliable technology that are affordable and attractive to accumulator operations associated with blow out preventers. The above discussed limitations in the prior art is not exhaustive. The current invention provides an inexpensive, time saving, more reliable apparatus, method and system bladder functionality where the prior art fails. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing disadvantages inherent in the known types of bladders utilized with piston accumulators now present in the prior art, the present invention provides a new and improved apparatus, system and method of use that provides better bladder performance. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved bladder for use with subsea piston accumulators for blow out preventers, which has all the advantages of the prior art devices and none of the disadvantages. 
     It is, therefore, contemplated that the present invention is an apparatus, system and method for improved bladder for use with subsea piston accumulators having a dispersion tube to ensure that hydraulic fluid stored in the bladder is sucked into the seawater chamber of the accumulator. The tube is ported allowing fluid to constantly be supplied to the chamber regardless of the fluid depth in the bladder. The invention also contemplates a special foot allowing the accumulator and bladder to be shipped in a horizontal position preventing the bladder and dispersion tube from being damaged and may further include a bladder cradle to distribute the weight of the fluid in the bladder reducing the stress on the fitting where the bladder foot is installed. 
     There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
     Therefore, it is an object of the present invention to provide a new and improved piston accumulator bladder apparatus, system and method for use in subsea piston accumulators that provides fluid as desired to the accumulator seawater chamber. 
     Furthermore, an object of the present invention is to provide a new and improved piston accumulator bladder apparatus, system and method, which allows for transmitting fluids utilizing a ported dispersion tube to allow fluid to constantly be supplied to the chamber regardless of the fluid depth in the bladder. 
     Another object of the present invention is to provide a new and improved piston accumulator bladder apparatus, system and method, which may include a special foot allowing the accumulator and bladder to be shipped in a horizontal position preventing the bladder and dispersion tube from being damaged and a bladder cradle designed to distribute the weight of the fluid in the bladder reducing the stress on the fitting where the bladder foot is installed. 
     It is a further object of the present invention to provide a new and improved piston accumulator bladder apparatus, system and method, which is of a durable and reliable construction and may be utilized in numerous types of piston accumulators. 
     An even further object of the present invention is to provide a new and improved piston accumulator bladder apparatus, system and method, which is susceptible to a low cost of installation and labor, which accordingly is then susceptible to low prices of sale to the consuming industry, thereby making such a system economically available to those in the field. 
     Still another object of the present invention is to provide a new and improved piston accumulator bladder apparatus, system and method, which provides all of the advantages of the prior art while simultaneously overcoming some of the disadvantages normally associated therewith. 
     These, together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages, and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE PICTORIAL ILLUSTRATIONS, GRAPHS, DRAWINGS, AND APPENDICES 
       The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed pictorial illustrations, graphs, drawings and appendices. 
         FIG. 1  is a general cross section illustration of a subsea piston accumulator and bladder system of a preferred embodiment in accordance with the invention. 
         FIG. 2  is a general cross section illustration of a bladder of a preferred embodiment in accordance with the invention. 
         FIG. 3  is a general cross section partial illustration of a lower portion of a bladder of a preferred embodiment in accordance with the invention. 
         FIG. 4  is a general cross section illustration of a dispersion tube of a preferred embodiment in accordance with the invention. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring to the illustrations, drawings, and pictures, and to  FIG. 1  in particular, reference character  10  generally designates a new and improved bladder for use with a piston accumulator apparatus, system and method of using same constructed in accordance with the present invention. Invention  10  is generally used in oil and gas well operations such as but not limited to blow out preventers and may be utilized in other operations not associated with oil and gas drilling operations. For purposes of convenience, the reference numeral  10  may generally be utilized for the indication of the invention, portion of the invention, preferred embodiments of the invention and so on. It is also to be understood that invention  10  should not be considered limited to an improved bladder and the term bladder should not be considered to limit the invention to such. Invention  10  may also include a new and improved accumulator apparatus, system and method as well as new and improved blowout preventer apparatus, system and method. 
     Bladder  20  may include a top  30 , a length  40 , a bottom  50 , an interior  60 , an exterior  70 , and outlet  80  for communicating fluid to subsea piston accumulator  90 . Bladder  20  may be made from nylon but is not limited to such. It is understood that bladder  20  may be elastomeric and or somewhat elastomeric to compress and expand depending on ambient subsea water pressure. Bladder  20  may include a liner  100  such as but not limited to plastic. Liner  100  generally lines the interior  60  of bladder  20 . 
     Invention  10  may include a dispersion tube  110  having a top  120 , a length  130 , a bottom  140 , an interior and or inner diameter  150 , an exterior and or outer diameter  160 , and so forth. Tube  110  may be made of stainless but is not limited to same. Length  130  may be 16 feet, interior diameter  150  may be about 1 inch, and outer diameter  160  may be an inch. It is understood that lengths, sizes, shapes and so forth may be larger and or smaller and the current invention  10  should not be considered limited to the illustrations and examples. Tube  110  may not necessarily be a round tube configuration and may be square, triangular and so forth. Tube  110  may include holes  170 , which may be drilled out and relatively small such as a ¼ inch but is to be understood that larger size, configuration and arrangement is contemplated. 
     Invention  10  dispersion tube  110  generally provides a structure wherein bladder  20  and or liner  100  may have a passageway for fluid to travel the length of bladder  20  even if part of liner  100  and bladder  20  collapse and impedes fluid flow when fluid is being moved to accumulator  90 . 
     Invention  10  contemplates generally fixing tube  110  inside bladder  20  liner  100  wherein top  120  of tube  110  is fixed at top  30  of bladder  20  and in communication  75  with outlet  80 . Communication  75  may be a hose, line, conduit and so forth as known in the art. Furthermore, tube  110  bottom  140  may be fixed at bladder  20  bottom  50 . In a preferred construction,  110  may be threaded at top  120  for securing to outlet  80 . Bottom  140  of tube  110  may be fixed by sliding in a foot  180 , which may be a larger diameter tube fixed by a bladder cradle  190 . It is understood that numerous other embodiments are contemplated to generally secure tube  110 . In a preferred construction, invention  10  may utilize cradle  190 , which may be fixed at bottom  50  of bladder  20  for supporting tube  110  during transportation and movement in general. 
     Accumulator  90  is known in the art and may include a nitrogen chamber  200 , working fluid chamber  210 , working fluid port  220 , seawater chamber  230 , seawater port  240 , a vacuum chamber  250 , and so forth. Conduit  260  may be between bladder  20  and seawater port  240  for communicating fluid  270  back and forth from bladder  20  to seawater chamber  230 . 
     It is therefore contemplated that the current invention may be a subsea piston accumulator and bladder system comprising: a subsea piston accumulator having a seawater port for selectively communicating liquid into and out of said subsea piston accumulator; a bladder having an interior and an aperture for communicating said liquid into and out said interior of said bladder; a liner disposed in said interior of said bladder, said liner having an interior adapted to hold said fluid and wherein said liner has an aperture for communicating said fluid into and out of said interior of said liner; and a dispersion tube a disposed in said liner, said dispersion tube having a first end with an aperture for communicating said fluid into and out of said dispersion tube, a length, a second end, and a plurality of apertures on said length adapted to communicate said liquid into and out of said dispersion tube and into and out of said interior of said liner. 
     It is also contemplated that the current invention may be a subsea piston accumulator and bladder system comprising wherein said second end of said dispersion tube is removably attached to said interior of said bladder via a cradle mounted to said interior of said bladder; wherein said cradle includes a foot adapted to allow said second end of said dispersion tube to slide into said foot; wherein said first end of said dispersion tube is fixed to said interior of said bladder; and wherein said second end of said dispersion tube is rounded. 
     Changes may be made in the combinations, operations, and arrangements of the various parts and elements described herein without departing from the spirit and scope of the invention. Furthermore, names, titles, headings and general division of the aforementioned are provided for convenience and therefore, should not be considered limiting.