BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, more particular description of the invention, briefly summarized above, may be had by reference to embodiments thereof which are illustrated in the appended drawings.
FIG. 1 is a schematic diagram in partial section with a position indication system of this invention installed on a BOP ram tail rod.
FIG. 2 is a detail schematic diagram is partial section of a dual light source configuration of this invention.
FIG. 3 is a schematic diagram of an audible indicator for this invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
FIG. 1 depicts a position indication system 10 mounted in functional arrangement with a BOP ram element 12. It should be understood that a complementary ram element (not shown) is positioned opposite the element 12 for actuation into the bore of a BOP. The element primarily comprises a ram 14 coupled to a rod 16, which is moved back and forth by a piston 18 under hydraulic pressure. An open port 20 provides hydraulic fluid under pressure to move the piston 18 (and therefore the ram 14) to the left, opening the ram. A close port 22 provides hydraulic fluid under pressure for the opposite motion, moving the piston to the right to shut the ram.
The piston 18 is retained within a cylinder 24, which is closed off at one end by an end cap 26 and at the other end by an end cap 28. The rod 16 penetrates the end cap 26 and is sealed with O-rings 30. Also, a tail rod 32 is coupled to and extends from the piston 18, so that the tail rod 32 moves reciprocally with the piston. The tail rod 32 penetrates the end cap 28 and is sealed with an O-ring 34.
The tail rod extends into a tail rod housing 36, which is long enough to accommodate the tail rod when the ram 14 is fully withdrawn, as illustrated in FIG. 1. At least one self-powered light 38 is installed on the tail rod 32 so that its light is selectively directed. At least one light receiver 40 is installed within the housing 36 so that, when the ram 14 is in a selected position, the light receiver 40 is positioned directly opposite the self-powered light 38. An optical fiber or fiber optic cable 42 carries the light received by the light receiver 40 from the light 38 to an optical-to-electrical converter 44. The optical-to-electrical converter 44 develops an electrical signal, which is transmitted over an electrical conductor 46 into a control panel 48.
The control panel 48 preferably includes at least one indicator light 50. With the arrangement illustrated in FIG. 1, with the ram 14 in the open position as shown, the self-powered light source 38 is positioned directly opposite the light receiver 40 and the light 50 will therefore be illuminated. Notice that no electrical power is required in the vicinity of the BOP, since the optical fiber 42 carries the light signal from the self-powered light 38 to a location remote from the ram element 12.
As previously described, the position indicator of this invention preferably includes at least one self-powered light source 38 and at least one light receiver 40. However, in a preferred embodiment, a second light receiver 40′ is provided. In this way, the light source 38 is positioned opposite the light receiver 40 when the ram is at full stroke in the open position, and opposite the light receiver 40′ when the ram is at full stroke in the closed position. In this preferred embodiment, the light receiver 40′ is coupled to an optical fiber 42′, which conducts light to an optical-to-electrical converter 44′. The optical to electrical converter 44′ develops an electrical signal, which is conducted over an electrical conductor 46′ to the control panel 48 to illuminate a light indicator 50′.
Preferably, the indicator light 50 is a different color than the indicator light 50′, so that an operator at the control panel 48 can easily determine by the color of the indicator light whether the BOP is open or shut. However, there are occasions when the operator needs to know that the BOP is between the open and shut positions. In this event, yet another light receiver 40″ is provided. The light receiver 40″ preferably extends from the vicinity close to the receiver 40 to the vicinity close to the receiver 40′. The light receiver 40″ receives light energy from the light 38 whenever the ram leaves the open position and before is reaches the closed position. An optical fiber or fiber optic cable 42″ conducts the light thus received to an optical-to-electrical converter 44″ which develops an electrical signal which is conducted over an electrical conductor 46″ to the control panel 48. This electrical signal illuminates an indicator light 50″, which is preferably of a color to indicate an unsafe condition, for example red.
Referring now to FIG. 2, a dual source configuration of this invention is depicted. In normal circumstances, a single self-powered light source is adequate since the ram of the BOP provides sufficient stroke length to move the light source from one light receiver to another light receiver. However, if the stroke is very small (i.e. small coil tubing applications, etc.), there may be insufficient lateral movement of the light source to adequately discriminate open from shut positions. In this event, for a small stroke S (FIG. 2), a second, self-powered light source 38 is provided. That way, the light source 38 of positioned next to the light receiver 40 if the ram is in the full open position, while a source 38′ is positioned next to a light receiver 40′ if the ram is in the shut position, with the tail rod moving only the distance S.
FIG. 2 also depicts additional details of the configuration of the self-powered light sources 38 and 38′. The light is preferably somewhat collumated by a light collar 62. An energy source, such as a tritium wand 64 emits decay energy which is received by a flourescing lens 60, which develops the light energy for transmission over the appropriate optical fiber 42, 42′, or 42″. This feature of the invention directs light directly onto the receiver, and not out into the tailrod housing where it may be received by another receiver as noise.
Finally, FIG. 3 illustrates an additional feature of the invention is it relates to an audible indicator, in place of or preferably in addition to the light indicators previously described. Each of the electrical conductors 46, 46′, and 46″ provide an input into a control module 70 which includes central processing unit 72. The CPA 72 interprets the electrical signals over the input lines as digital signals. A light input from the receiver 40, and no input from the other receiver(s), is interpreted as indicating that the ram is shut, and an audible signal, including a voice generation signal, is provided by the CPU that that the ram is shut. Similarly, a light signal received by the receiver 40′ (and no other signals) indicates that the ram is shut, and an audible signal, such as a tone or a voice signal, indicates such by a speaker 74. If the ram is in an intermediate position for longer than a predetermined period of time, indicating an unsafe condition for the ram, a different signal is generated by the CPU, including an alarm signal or a voice signal telling the operator of the condition.
The principles, preferred embodiment, and mode of operation of the present invention have been described in the foregoing specification. This invention is not to be construed as limited to the particular forms disclosed, since these are regarded as illustrative rather than restrictive. Moreover, variations and changes may be made by those skilled in the art without departing from the spirit of the invention.
Patent Application
20080040070
