Patent Application
20190234822
Releasing/replacing components of high pressure fluid systems without de-pressurizing or shutting down the system under pressure can be challenging. It will be appreciated that such systems may be costly to shut-down and present safety hazards whenever replacing the components under pressure. With respect to the latter, a pin-hole or fluid-stream under high-pressure, e.g., twenty-thousand (20,000) psi, can quickly become a fluid knife capable of inflicting serious operator injury.
In some instances, systems and methods for pressure measurement, whether being performed on-shore or in sub-sea applications, include devices which include a pressure measuring sensor. Such sensors can require at least two access ports to allow a counteracting pressure to be introduced for installation/calibration and retrieval of the plug/sensor. As mentioned in the preceding paragraph, additional access ports can createan opportunity for a hazardous condition. Commonly-owned U.S. Patent Publication 2014/0298914 describes a retrievable pressure sensor for in-situ measurement of pressure in a process fluid and is hereby incorporated herein by reference in its entirety.
In practice, the use of valves has proven to be difficult in some circumstances inasmuch as, when left in an open position for a prolonged period, the valves can be subject to being fouled by the process fluid. A risk is, therefore, imposed by a potentially faulty valve, i.e., an inoperable valve, when it is finally employed for the replacement of a pressure sensor, i.e., some 10-15 years later. Moreover, when such valves are eventually used, it can be difficult to avoid discharge of the process fluid into the environment. It will be appreciated that such discharge may require costly environmental clean-up of the surrounding water supply or soil.
The subject matter disclosed herein relates to a device facilitating the release and replacement of valves in high pressure fluid systems and, more particularly, to an access/retrieval plug configured for in-situ measurement of pressure in a process fluid.
For example, it may be beneficial for a sensor retrieval system to facilitate the removal and replacement of a component, e.g., a pressure sensor, disposed in a high pressure fluid environment which does not render the component inoperable and/or require a suspension in production/process when opening the pipe or conduit to its surrounding environment. The sensor retrieval system may meet safety requirements, which may be strict.
The system comprises a retrieval plug having a first end portion disposed within a first cavity of a process-fluid conduit, and a second end disposed within a second cavity of a blind flange fitting. The first cavity is exposed to the pressure environment of the process fluid and the retrieval plug is configured to transfer an indicated pressure from the first to the second end portion. A cap is disposed between the blind flange and the second end portion of the retrieval plug. Furthermore, the cap is configured to transfer the indicated pressure to a pressure measurement sensor disposed remotely of the retrieval plug.
A method is also provided for protecting an operator from a high pressure waterjet discharge by encapsulating an access/retrieval plug within a cavity of a blind flange. The method comprising the steps of: communicating an indicated pressure of a process fluid through a retrieval plug, and communicating the indicated pressure to a remote sensor. The above embodiments are exemplary only. Other embodiments are within the scope of the disclosed subject matter.
So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the disclosed subject matter encompasses other embodiments as well. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views.
The disclosure describes a system and method for use in connection with fluids under pressure which may be contained within a high pressure fluid conduit. Such fluids can create a hazardous condition for operators assigned to repair and replace internal components as may be required during routine maintenance or when a condition calls for maintenance attention. The system produces an interface or connection within a cavity of the fitting which facilitates pressure measurement across the interface while allowing an operator to safely disconnect or decouple the fitting from the fluid conduit. A pair of opposed diaphragms produce the interface wherein the displacement of one diaphragm may be communicated to the other diaphragm so as to allow a remote pressure sensor to measure the fluid pressure.
More specifically, the disclosure describes transferring information, e.g., pressure information, across a plug which provides access to the process fluid in a high pressure system. The system may employ a series of transfer tubes and a modified access plug to transfer information to a remote sensor. The remote sensor may be repaired and replaced without the need to open the high-pressure system to atmosphere and/or to expose an operator to the hazards associated with repair and replacement. Furthermore, the system can employ a redundant series of sealing interfaces, which may improve system safety and prevent contamination/leakage. Finally, the simplified system can minimize the opportunity for flaws in the repair of internal components.
An exemplary embodiment of the disclosure is described in the context of a high-pressure well-head for an oil drilling platform, although the teachings described herein are equally applicable to other systems, including any high pressure fluid system having a requirement for periodic repair and/or replacement of a sensor, valve or other component. Pressure can be communicated across various interfaces such as across diaphragms, through one or more transfer tubes, or across a compliant interface. This is not communicated as an actual pressure value, but rather, as a physical/tangible/measureable displacement indicative of a pressure value. Ultimately, pressure may be detected or measured by a sensor measurement device 80. In some instances, the sensor measurement device 80 may be located remotely or outside of the blind flange 28.
In the described embodiment, a first end portion 30 of the access/retrieval plug 22 is disposed within a cavity 32 of the conduit wall 18 which provides access to process fluid 16, and to the internal pressure thereof, through an access port 34. When pressurized, the range of operating pressures will be between atmospheric to about twenty-thousand psi (14.7 to 20000 psi). A second end portion 36 of the access/retrieval plug 22 is received within the cavity 26 of the blind flange or fitting 28. A gasket 40 may be disposed within first and second annular grooves 42a, 42b of the conduit wall 18 and the blind flange 28, respectively, to produce a first sealing interface 44 (see
While the access/retrieval plug 22 is used principally to facilitate the removal and replacement of valves within the high-pressure fluid environment, the access/retrieval plug 22 can facilitate the access, repair, replacement, retrieval and installation of virtually any component used in such environments. Accordingly, the following description uses the terms “access” “retrieval” and “removal” interchangeably as modifiers for the plug 22. As mentioned in the preceding paragraph, the first end portion 30 is disposed within the first cavity 32 of the conduit wall 18 while the second end portion 36 is disposed within a second cavity 38 of the blind flange fitting 28. In
Similarly, and referring to
The spring-biased cap 24 can be disposed over the second end portion 36 of the access/retrieval plug 22 and within the second cavity 38 of the blind flange 28. Moreover, the spring-biased cap 24 is configured to: (i) transfer the indicated pressure PI to a remote sensor 80 (see
In the described embodiment, the coil spring 68 (illustrated in
Similar to the face surfaces of the access/retrieval plug 22, the spring-biased cap 24 may also form a concave surface 72 bounded by a third metal diaphragm 70 which, together, define a third defined volume or reservoir 74. The third diaphragm 70 is laterally aligned, and/or contiguous with, the second diaphragm 60 such that an axial displacement of the second diaphragm 60 can be communicated to the third diaphragm 70. The concave surface 72 is surrounded by a first annular abutment surface 46a disposed radially outward of the concave surface 72. The first annular abutment surface 46a forms a first half of the second sealing interface 46 while a second annular abutment surface 46b, disposed radially outboard of the concave surface 62, forms a second half of the second sealing interface 46. In the described embodiment, the first and second annular abutment surfaces 46a, 46b may form any geometric shape, e.g., planar, converging, diverging, conical, concave and convex surfaces, etc. In the described embodiment, the abutment surfaces 46a, 46b, are orthogonal to a pressure vector V produced by the process fluid 16.
The coil spring 68, therefore, produces a counteracting force vector F which equilibrates the pressure vector V induced by the process fluid 16. While the forces and pressures exerted along the mating interface 46b can be high, i.e., pressure across the second and third diaphragms 60, 70, the coil spring 68 functions to seat the cap 24 against plug 22 such that the pressure within the second diaphragm 60 is contained by the third diaphragm 70. It will be appreciated that the second diaphragm 60 is influenced, sometimes directly, by the pressure induced by the process fluid 16 which is transferred to the second diaphragm 60 via the first diaphragm 50 and lower/first transfer tube 48a. As such, a propensity exists for the second diaphragm 60 to rupture should a counteracting force be removed, such as that provided by the spring-biased cap 24 It is also for this reason that the interface 46b that the interface 46 is fully encapsulated within the protective, bell-shaped, enclosure or cavities 26, 32 of the conduit 18 and blind flange 28, respectively.
In the described embodiment, the upper transfer tube 48b comprises a series of transfer tubes 48b-1, 48b-2, and 48b-3 from the third reservoir 74 to the remote sensor 80. More specifically, a first portion 48b-1 of the upper transfer tube 48b is disposed in the cap 24, a second portion 48b-2 of the tube 48b is disposed in the blind flange 28, and/or a third portion 48b-3 is disposed between the first and second portions 48b-1, 48b-2. The third portion 48b-3 may comprise a compliant tubing, connecting the first and second transfer tubes 48b-1, 48b-2 to accommodate a small degree of axial and/or lateral displacement of the spring-biased cap 24. In the described embodiment, the flexible tubing 48b-3 is disposed internally of the cylindrical volume or central void 76 of the coil spring 68, however, this may simply be a convenient location for the flexible tubing 48b-3.
In the described embodiment, the diaphragms 50, 60, 70 are configured to communicate information regarding the high pressure process fluids from the first diaphragm 50 to the pressure sensor 80. In some instances, in development of the hot swappable pressure sensing system, it was discovered that the system can be most reliable when employing relatively small components and volumes to minimize the pressures acting on the various components. In the described embodiment, the diaphragms 50, 60, 70 each have a diameter dimension which is less than about two inches (2.0″) and, in some instances, less than about one and one half inches (1.50″). Furthermore, the upper and lower transfer/capillary tubes 48a, 48b are less than about one millimeter in diameter. Once again, these dimensions may be standard and are not be deemed limiting when considering the breath of the claimed invention.
The first reservoir 54, transfer tube 48a, and second reservoir 64 may contain an incompressible fluid which is conductive or non-conductive (i.e., a dielectric fluid). While nearly any incompressible fluid may fill the access/retrieval plug 22, in some embodiments, a liquid metal fluid may be best suited to fill the retrieval plug 22. That is, while fluids such as water and oil may be employed, these fluids are, at least to some small degree, compressible under the extremely high pressures of the process fluid 16. Accordingly, metallic fluids which exhibit improved properties, i.e., nearly incompressible even at pressures greater than 5,000 psi, may be best-suited in some instances to fill the transfer tube and reservoirs 48a, 50, 60 of the access/retrieval plug 22. In the described embodiment, liquid metals from the group consisting of: bromine, mercury, cesium, francium, gallium and rubidium may exhibit such favorable properties. It should also be appreciated that the foregoing elements may be mixed with compatible alloys to improve the incompressible properties of the fluid.
While the incompressible fluid which fills the release plug 22 (i.e., the first and second volumes 54, 64 and lower transfer tube 48a) may be a liquid metal, the incompressible fluid filling the spring-biased cap 24 (i.e., the upper transfer tube 48b, and the third volume 74) can comprise a non-conductive, dielectric material. This property may be desirable in some embodiments to prevent a voltage or current from adversely affecting the remote pressure sensor 80. Therefore, the incompressible fluid which is best-suited to fill the upper transfer tube 48b and the third reservoir 74 can be a conventional non-conductive silicone oil. As a consequence, the system 20 may employ two incompressible fluids, i.e., a metallic fluid filling the access/retrieval plug 22 and a non-metallic, non-conductive, dielectric fluid filling the spring-biased cap 24.
In operation, and referring collectively to
The diaphragms 50, 60, 70, and transfer tubes 48a, 48b provide a fully enclosed system for measuring the high pressure environment of a contemporary oil drilling platform. The remote location of the measurement sensor 80 can facilitate ease of repair/replacement while also allowing access for other purposes. The spring-biased cap 24 produces a sealing interface 46a between the second and third diaphragms 60, 70, or between the spring-biased cap 24 and the second end 36 of the access/retrieval plug 22. The coil spring 68 provides the requisite force, i.e., the product of the process fluid pressure multiplied by the diaphragm area (V×A=F×A, where V is the force vector induced by the process fluid 16, F is the force vector induced by the coil spring 68, and A is the affected area of diaphragm 60 acting on diaphragm 70), to counteract the separation force along the second sealing interface 46b.
The foregoing, therefore, also can also describe a method which facilitates the repair and replacement of consumable components in a high pressure oil distribution system 20. The method comprises the steps of: communicating an indicated pressure PI of a process fluid through a retrieval plug 22 and communicating the indicated pressure 22 to a remote sensor 80. In some embodiments, one of the principle safety advantages can be achieved by producing a primary sealing interface 44 and a redundant sealing interface 46. These steps can include mounting the cap 24 within the blind flange fitting 28 such that a mating interface 46 is produced between the retrieval plug 22 and the mounting cap 24, and encapsulating or placing the mating interface 46 within a protective cavity 36 produced by the blind flange/fitting 28.
To ensure that the system 20 of the present invention is safe in some or all operational modes, a first step in its disassembly is the separation and/or disengagement of the mating interface 46. More specifically, and referring again to
Prior to disengaging the blind flange 28 from the conduit 18, it can be necessary to disengage the mating interface 46 to prevent damage, i.e. rupture of the second mating diaphragm 60, to various system components. To ensure that the plug 22 may be removed without damage, there may be a need to include a means for varying the volume of the incompressible fluid filling the cap 24, i.e., the third reservoir 74 and the transfer tube 48b. This may be achieved by adding fixed quantities of fluid to the reservoir 74 during or immediately prior to disassembly of the blind flange 28 and the access plug 22. The means for introducing or removing fluid from the reservoir 74 is illustrated and described in greater detail in Seeberg et al. U.S. Patent Publication 2014/0373635 entitled “Retrievable Sensor and Method” and is herein incorporated by reference in its entirety.
The access/retrieval plug 22 arrangement, therefore, can reduce: (i) the risk of environmental contamination during replacement of the sensor 80, (ii) hazardous emissions such as exposure to hydrogen sulfide, (iii) the requirement for PPM and/or, (iv) the requirement for expensive tools and equipment, e.g., double block and bleed valves.
To the extent that the claims recite the phrase “at least one of” in reference to a plurality of elements, this is intended to mean at least one or more of the listed elements, and is not limited to at least one of each element. For example, “at least one of an element A, element B, and element C,” is intended to indicate element A alone, or element B alone, or element C alone, or any combination thereof “At least one of element A, element B, and element C” is not intended to be limited to at least one of an element A, at least one of an element B, and at least one of an element C.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
This application is a Non-Provisional patent application and claims the benefit and priority of U.S. Provisional Patent Application No. 62/405,497, filed on Oct. 7, 2016. The entire content and disclosure of such application are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US17/55500 | 10/6/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62405497 | Oct 2016 | US |
