Patent Application
20090134995
The present invention relates generally to enclosures for working environments, and more particularly relates to a system and methodology for avoiding unsafe conditions in and around such enclosures.
There are various settings in which it is necessary or desirable to provide a barrier between a particular working environment and the area surrounding it. Such settings are typically industrial in nature, and a prominent example of such is found on oil and gas drilling facilities, such as offshore platforms, production facilities and the like, in which industrial activities of various sorts regularly occurs in close proximity to areas in which the activity would be considered dangerous, or in which the environment in general is not suited to performing certain activities.
In the case of offshore drilling platforms, it is very common for welding operations to be performed. Welding, of course, involves the generation of extremely high temperatures, flames and/or electrical arcs, sparks and fragments of materials being sprayed in uncontrolled directions. It is obviously not advisable or desirable for such activities to be performed in close proximity to hydrocarbon liquids and gases, which for the most part are highly combustible.
In recognition of these concerns, there has been proposed in the prior art the concept of an enclosure intended to surround a working area and isolate the working area from potentially hazardous external conditions in close proximity to the working area. Examples of such enclosures are proposed, for example, in U.S. Pat. No. 7,193,501 to Albarado et al. entitled “Enclosure System Allowing for Hot Work Within the Vicinity of Flammable and Combustible Material;” in related U.S. Pat. No. 7,091,848 to Albarado, entitled “Enclosure System for Hot Work Within the Vicinity of Flammable or Combustible Material;” in U.S. Pat. No. 6,783,054 to Pregeant, Jr. et al., entitled “System for Controllably Conducting Welding Operations Adjacent Flammable Materials and Method of Welding Adjacent Flammable Materials;” and in related U.S. Pat. Nos. 5,101,604 and 5,018,321 to Wardlaw, III, each being entitled “Subterranean Well Welding Habitat.” Each of the foregoing U.S. Patents are hereby incorporated by reference herein in their respective entireties.
While such work area enclosure systems are known, especially in the oil and gas industry, many implementations do not take into account the potential for the activities or conditions inside the enclosure creating hazardous conditions, such as, for example, if an enclosure contained dangerous concentrations of volatile and/or injurious gases and the like. Such conditions are to be carefully avoided to ensure the safety of persons both inside and outside the working area enclosure.
To address these concerns, there have further been proposed in the art various means for ensuring the safety of persons both within and outside of a workspace enclosure. For example, there has been proposed the provision of sensing devices adapted to signal the presence of combustible or otherwise hazardous conditions within the enclosure. The aforementioned Pregeant, Jr. et al. '054 patent (“Pregeant”), for one, appears to disclose a welding enclosure having one or more sensors for detection of some potentially hazardous condition(s), and for controlling the operations of the welding apparatus in response to signals from the sensor(s).
Notwithstanding the apparent safety benefits arising from the Pregeant disclosure and others in the prior art, there are certain perceived disadvantages to the system proposed in the prior art that make such systems and methods less than optimal in certain respects, and it is believed that there remains an ongoing need for improvements in prior workspace enclosures and the control and safety systems associated with those enclosures.
In view of the foregoing, the present invention is directed to a workspace enclosure system including an emergency shut-off mechanism. In one embodiment, the emergency shut-off mechanism comprises an emergency shut-off panel disposed within the workspace enclosure itself. The shut-off mechanism includes solenoid controlled valves for regulating the delivery of welding gases to welding equipment in the enclosure, as well as electrical switching mechanisms for regulating the delivery of welding current from a welding machine disposed outside the enclosure.
In accordance with one aspect of the invention, by disposing the emergency shut-off mechanism within the workspace enclosure, the need to take precautions concerning potential combustion outside of the enclosure due to the activation of solenoid valves or welding current switching circuitry is advantageously eliminated.
In accordance with another aspect of the invention, canisters containing the welding gases can be coupled directly to the emergency shut-off mechanism without the need for equipping the canisters with the necessary valves to control the delivery of welding gases. This means that the system may be implemented with a wider variety of welding equipment without the need for special retrofitting or modification to the welding equipment.
In accordance with another aspect of the invention, an air intake/sensor unit is coupled via a substantially closed air-handling system to the intake of a blower providing air to the interior of the enclosure to maintain a positive pressure therein. Due to the closed nature of the air flow system, it can be assured that any air or gas entering the enclosure will be subjected to analysis by one or more sensors in the intake/sensor unit. That is, no un-analyzed air can be sent into the enclosure.
In one embodiment, the intake/sensor unit is configured with a baffle structure for creating eddy currents within the unit, thereby maximizing the exposure of air passing through the unit to the internal sensor(s).
The foregoing and other features and aspects of the present invention will be best appreciated by reference to a detailed description of the specific embodiments of the invention, when read in conjunction with the accompanying drawings, wherein:
a is an isometric view, and
In the disclosure that follows, in the interest of clarity, not all features of actual implementations are described. It will of course be appreciated that in the development of any such actual implementation, as in any such project, numerous engineering and technical decisions must be made to achieve the developers' specific goals and subgoals (e.g., compliance with system and technical constraints), which will vary from one implementation to another. Moreover, attention will necessarily be paid to proper engineering practices for the environment in question. It will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the relevant fields.
Referring to
As will be apparent to those of ordinary skill in the art, system 10 is adapted for use both with gas-based (e.g., oxy-acetylene) welding/cutting equipment and with electricity-based (e.g. arc-welding) equipment. (Presently, oxy-acetylene equipment predominates the general class of gas-based welding/cutting equipment, and although the term oxy-acetylene is used throughout this disclosure, it will be apparent to those of ordinary skill in the art that the invention is applicable to any type of gas-based system. Similarly, the term arc-welding is used herein as a general term for any form of electricity-based welding systems, such as are well-known in the art.) System 10 as shown in
Thus,
As is further shown in
Welding machine 24 is also coupled to controller 22 by means of power lines 30, upon which the welding current is carried for performance of a welding operation using electrodes 18.
A plurality of gas supply canisters 32-1 . . . 32-n are coupled to controller via hoses having valves 34-1 . . . 34-n which are also solenoid-type valves controlled by controller 22 to permit welding/cutting gases (e.g., oxygen and acetylene) to be supplied to welding torch 20.
As will be known to those of ordinary skill in the art, it is desirable to maintain a positive pressure within enclosure 12, i.e., to ensure that the air pressure within enclosure 12 is some degree greater than the outside air pressure. Among other things, this avoids the build-up of potentially combustible gases within enclosure 12, thereby providing users within the enclosure a measure of safety.
To accomplish this, and in accordance with the prior art, a blower 36 is coupled to enclosure 12 to intake external air 38 and continuously blow the intake are into housing 12.
Optionally, the enclosure 12 may further include an output blower (not shown in
In accordance with one conventional implementation, there is provided one or more sensors 40 at the intake of blower 36 for detecting the presence of unwanted gases in the air 38 in the vicinity of the blower intake, in order to avoid introducing such gases into the enclosure 12.
In accordance with conventional practice, system 10 further includes at least one, and usually a plurality of sensors 42 disposed within enclosure 12 for detecting the presence of undesirable gases, or undesirable concentrations of gases, and/or other undesirable conditions within enclosure 12 that would pose a danger to workers in the enclosure. The outputs from sensors 42 are electrical signals that are coupled to controller 22.
With continued reference to
In the operation of system 10, controller 22 receives sensor signals from the various sensors in system 10, and in the event that any undesirable conditions are detected by one or more sensors, controller 22 can immediately shut down the welding/cutting operation by disconnecting or deactivating various components. For example, controller 22 is coupled to valves 34-1 . . . 34-n and is capable of shutting of delivery of welding gases to the torch 20 in enclosure 12. Furthermore, controller 22 can operate to decouple the entire system from its power source 50.
Preferably, controller 22 is also interfaced with a platform shutdown signal 52 such that system 10 can be responsive to platform-wide emergencies or other circumstances in which it is critical to disable all operating equipment on the platform.
Referring now to
In a preferred embodiment, the workspace enclosure's flexible (e.g., fabric) walls expand to suit the available space on the platform and isolate a welding area, safely containing the heat-source by maintaining a positive air-pressure within. The size of any given enclosure can be customized due to the modular nature of the enclosure's components. The positive-pressure system works in the same way as that of the accommodation block on an off-shore platform by creating a virtual air-lock within the enclosure and is maintained by means of continuous air-flow input and extraction, as is known in the art. A ratio on the order of 2:1 input to extraction has been found to be sufficient to ensure that the enclosure is inflated at all times and that the air inside is always clean and free of outside contaminants.
In one embodiment, the enclosure's floor and walls are manufactured from a light-weight, heat-resistant fabric which confines sparks and splatters. Custom-built sleeves adapted to slip easily over pipes and around beams to create a seal are preferably provided.
The enclosure is adapted to be installed around or over a workspace area to be secured and inflated using a blower which applies an air-input of between 700 and 1200 CFM and a positive pressure of between 10 and 20 Pascals. Optionally, an additional exhaust blower provides positive pressure and constant air circulation inside the welding chamber. Such blowers are available as air or electrically-driven units and can be located away from the enclosure itself. In one embodiment, workspace enclosure 102 may be assembled within and held upright by means of an external scaffolding structure or the like, or may have certain key portions of the enclosure tied or otherwise secured to existing structures in the workspace environment.
The flexible and modular nature of an enclosure structure in accordance with the present invention is that a workspace enclosure can be more readily established in areas with uneven floors or other surfaces than would a completely rigid (e.g., plywood or the like) enclosures.
In another variant of the invention, a modular portion of the fabric comprising the enclosure is replaced with a rigid access panel (e.g., an access panel including a frame and a securable door capable of being opened by persons both within and without the enclosure.) promoting ease of entry and exit into and from the enclosure 102. The modular nature of enclosure 102 in the preferred embodiment easily lends itself to such an option, as would be appreciated by those of ordinary skill in the art.
Enclosure 102 defines an enclosed workspace 104 containing electricity-based welding electrodes 106 and/or a gas-based welding/cutting torch 108, as described above with reference to
In accordance with one aspect of the invention, in the embodiment of
It is to be noted that in prior art systems, such as that described with reference to
As shown in
As shown in
As in the prior art, such as described with reference to
In accordance with one aspect of the invention, the intake of blower 126 is coupled either directly or via ductwork 132 or any other substantially closed means of containing and directing the flow of gases to the output of an intake sensor module 134 which is adapted to steer incoming air 136 past an intake sensor 138 as the air 136 is drawn in due to the suction force of blower 126.
With reference to
It is believed that the arrangement of blower 126 and intake/sensor module 134 offers advantages over the prior art, such as the prior art described herein with reference to
With continued reference to
As would be appreciated by those of ordinary skill in the art, elimination of the need for a dedicated inert gas canister has the advantage of simplifying the system as a whole, reducing the number of components making up the system and hence reducing not only the costs of creating and operating the system, but also the amount of space occupied by the system as a whole. It is widely understood that in environments such as drilling platforms and the like, all space is at a premium, and any reduction in the size of operating equipment is considered highly desirable.
In
As described herein, the presently preferred embodiment of the invention is believed to offer several significant advantages over prior art systems. These advantages may not be immediately evident even to those of ordinary skill in the art, but they include, without limitation:
Although specific embodiments and variants of the invention have been described herein in some detail, it is to be understood that this has been done solely for the purposes of illustrating various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention, as defined in the claims. It is contemplated and to be understood that various substitutions, alterations, and/or modifications, including such implementation variants and options as may have been specifically noted or suggested herein, may be made to the disclosed embodiment of the invention without departing from the spirit or scope of the invention.
