Patent Application
20170217739
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource.
Offshore drilling platforms often include hoisting systems for raising and lowering equipment. In some instances, these hoisting systems take the form of cranes used to load and unload equipment from an offshore platform. Of course, cranes and other hoisting systems can be used onshore as well. Cranes often include hoisting lines that are spooled from drums, reeved over sheaves in upper blocks at fixed locations in booms of the cranes (e.g., at the ends of the booms), and are connected to loads via lower, traveling blocks (or hook assemblies) at the ends of the hoisting lines. When raising connected loads with cranes, care is taken to avoid contact between the upper and lower blocks. Such contact, which is referred to as two-blocking, can interfere with crane operation and lead to failure of a hoisting line or disconnection of the suspended load from the hoisting line. Various anti-two-block sensing devices have been used on cranes to help avoid two-blocking.
Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
At least some embodiments of the present disclosure generally relate to anti-two-block safety systems intended to warn or stop hoisting or crane motion that would cause a two-block condition between a traveling hook block and an upper block of a crane. In certain embodiments, an anti-two-block sensing device includes a chandelier that can be hung below an upper block of a crane and can receive the hoisting line. The sensing device in at least one embodiment includes a trigger assembly for detecting an actuator coupled to the hoisting line and raised into contact with the trigger assembly. In one embodiment, the sensing device has a low-maintenance design devoid of seals, springs, lubricants, and precision sliding components. A sensing cap having proximity sensors or other detectors can be mounted on the chandelier for detecting the approach of the lower block toward the upper block and triggering alerts or preventive measures to avoid two-blocking.
Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter.
These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Specific embodiments of the present disclosure are described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components.
Turning now to the present figures, a hoisting system 10 is illustrated in
The depicted crane 12 is a knuckle-jib crane having a boom with a main beam 16 connected to a second beam 18. The illustrated system 10 includes a hoisting line 20 reeled out from a rotatable drum 22 on the crane 12. The hoisting line 20 is reeved through sheaves 24 and 26, and a hook assembly 28 with a hook 30 on the end of the hoisting line 20 is used to connect the hoisting line 20 to a load (e.g., supplies or equipment to be lifted by the crane 12). Once connected, the hoisting line 20 can be reeled in or reeled out from the drum 22 to raise or lower the load. Any suitable hoisting line 20 could be used with the hoisting system 10, such as a wire rope, a fiber rope, or a metal cable.
The hoisting system 10 includes an anti-two-block sensing device 32 intended to detect when the hook 30 (or other moving component coupled to the hoisting line 20) reaches a predetermined distance from the boom tip of the crane 12. In the presently depicted embodiment, the anti-two-block sensing device 32 is suspended from the end of the boom of the crane 12 via chains 34, although the sensing device 32 could instead be suspended with cables or in some other suitable manner. The hoisting line 20 extends downwardly from the end of the boom through the sensing device 32 to the hook assembly 28. An actuator 36 (e.g., a strike plate) is coupled to the hoisting line 20 for engaging a trigger of the sensing device 32, as discussed in greater detail below. In some hoisting systems, the hoisting line 20 will move through the sensing device 32; in others, the hoisting line 20 in the sensing device 32 will remain stationary, while the actuator 36 is a traveling block or other component that will move relative to the sensing device 32. Although the use of the sensing device 32 with a jib crane is generally depicted in
The anti-two-block sensing device 32 is illustrated in greater detail in
The main body 42 (which may also be referred to as a chandelier) can be suspended from a crane via lifting eyes 64. The trigger device 44 is coupled to the main body 42 via links that allow the trigger device 44 to freely move between a resting position, as shown in
The anti-two-block sensing device 32 includes one or more detectors for identifying movement of the trigger device 44. More particularly, in at least some embodiments the sensing device 32 includes a proximity sensor for detecting movement of a link caused by movement of the trigger device 44 toward the main body 42 (e.g., when driven upwardly by the actuator 36). If the sensing device 32 includes a cap 46 mounted on the main body 42, the proximity sensor or other detector can be installed in the cap 46 (e.g., as detector 128 of
Two of the heads 56 are shown in
In at least some embodiments, the detectors continuously (or continually) sense the targets 60 during normal hoisting operations (e.g., while moving the hoisting line 20 through the sensing device 32) until the trigger device 44 is moved through contact with the actuator 36, which causes lifting of the targets 60 as described above. Further, in this arrangement improper adjustment (or malfunctioning) of the detectors can be indicated by the inability of the detectors to “see” the targets 60 during normal conditions (i.e., in which the trigger device 44 has not been actuated). This is in contrast to other possible arrangements in which the detectors are used to detect movement of objects into the detection zone of the sensors upon actuation of the trigger device 44.
Any suitable detectors could be used for sensing the presence or absence of the targets 60. In at least some instances, the detectors are provided as solid-state, non-contact sensing devices. Further, in certain embodiments the detectors are provided as inductive proximity sensors that detect metal targets 60. Other proximity sensors (e.g., acoustic, capacitive, or infrared sensors), or other forms of detectors, could be used in additional embodiments. And while two detectors are described above for detecting the targets 60 shown in
As noted above, the depicted anti-two-block sensing device 32 includes lifting eyes 64 for connecting the sensing device 32 in a hoisting system (e.g., suspended from the boom of the crane 12 via the chains 34). Although other embodiments may differ, the sensing device 32 in
It will be appreciated that the ability to transversely install the plates 70, 72, 90, and 92 about the hoisting line 20 enables the main body 42 and the trigger device 44 to be installed on an assembled hoisting line system (e.g., without disconnecting the hoisting line 20 from the hook assembly 28 and threading the hoisting line through each of the plates). Although no individual plate of the main body 42 and the trigger device 44 fully surrounds the hoisting line 20 (due to their slots), once positioned about the hoisting line 20 the plates may be aligned and fastened together so that their slots are offset from one another such that the plates cooperate to fully encircle the hoisting line 20. More particularly, the slots 76 and 82 are rotationally offset from one another such that the plates 70 and 72 of the main body 42 cooperate to fully surround the hoisting line 20. Similarly, the slots 96 and 102 are offset from one another so the plates 90 and 92 of the trigger device 44 also cooperate to fully surround the hoisting line 20. Further, as shown in
In contrast to some previous anti-two-block sensing devices, in at least some embodiments of the present disclosure the sensing device 32 is devoid of seals, springs, and sliding surfaces (e.g., precision plungers) requiring periodic lubrication. Further by not using lubricants or seals, the sensing device 32 of at least some embodiments is a low-maintenance (or effectively a no-maintenance) device in that it does not require manual intervention to lubricate sliding surfaces or routinely replace parts. It can also be assembled over an intact hoisting line and still have full circumferential contact with the wire rope. Further, the operation of the sensing of the targets 60 is insensitive to the weight of the linkages suspending the trigger device 44 from the chandelier 42 in at least some embodiments.
As noted above, the anti-two-block sensing device 32 of some embodiments includes a cap 46 coupled to the main body 42. In one embodiment generally depicted in
The half-shells 110 of the cap 46 are shown assembled about the hoisting line 20 in
In some instances, the detectors 128 include proximity sensors used to detect targets 60 moved through actuation of the trigger device 44, as described above. In other embodiments, however, the detectors 128 are also or instead used to sense one or more components (which may also be referred to as targets) provided on the hoisting line itself. For example, such components (e.g., a metallic material or radio-frequency identification tags) can be embedded in a sleeve 142 positioned about the hoisting line 20 as generally shown in
As depicted in
An example of a hoisting control system 152 is generally depicted in
In still other embodiments, the targets sensed by the detectors 128 (or 154) are radio-frequency identification (RFID) tags positioned along the hoisting line 20. One example of such an embodiment is depicted in
The length of the sleeve 142 can be varied between different implementations. For instance, the length can vary depending on the speed or rate of travel of the hoisting line 20. In one embodiment, the sleeve 142 is placed around the hoisting line 20 extending upward from a location starting at the actuator 36 (e.g., a strike plate) located at the top of a hook ball/weight, as generally depicted in
It is noted that a controller 156 for implementing various functionality described herein (e.g., slowing or stopping hoisting in response to signals from anti-two-block sensing device 32) can be provided in any suitable form. In at least some embodiments, such a controller 156 is provided in the form of a processor-based system, an example of which is illustrated in
While the aspects of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
