Abstract:
The present invention generally an apparatus and a method for filling tanks with acetylene gas. The invention includes filling a first tank to a first level, thereafter filling a second tank while continuing to fill the first tank. The invention further includes restricting the flow of gas to the second tank while continuing to fill the first tank. The invention also includes a first and a second transportable source of compressed acetylene.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional of U.S. patent application Ser. No. 10/641,204, filed Aug. 14, 2003, which claims benefit of U.S. Provisional Patent Application Ser. No. 60/404,028, filed Aug. 16, 2002, both of which are herein incorporated by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method and an apparatus for supplying compressed gas to a point of use. More particularly, the invention relates to an acetylene distribution system that fills a transportable source of gas that can be located at a worksite, used and then removed and replaced by another transportable source. 
   2. Description of the Related Art 
   Compressed fuel gases, especially gases such as acetylene, are well known and widely used in construction and manufacturing. Typically, acetylene is mixed with oxygen at a point of use to provide a combustible mixture. Because of its volatility, acetylene must be carefully handled before and during use. Conventionally, acetylene is provided at a point of use in a cylinder that can be delivered and then removed and refilled. 
   In addition to simple welding operations requiring a single cylinder, there are many operations that make use of large amounts of acetylene, making the use of a single cylinder at a time impractical. In these instances, several cylinders can be used in combination with a manifold to provide a constant source of acetylene to an operation. In one prior art arrangement, cylinders are delivered to the worksite connected together with a manifold and, with the use of equipment to regulate pressure, used to provide regulated acetylene to an operation. More recently, cylinders have been arranged on a trailer and then used at a site while remaining on the trailer. This approach eliminates the unloading and reloading of the cylinders at the point of use, and consequently makes it easier to replace empty cylinders with filled cylinders. 
   Typically, the trailer is taken to an acetylene supply plant to fill the cylinders with acetylene. The acetylene plant consists of a trailer filling system that connects to the manifold on the trailer to facilitate the filling of the cylinders. In a conventional filling system, multiple trailers are filled simultaneously. However, due to the chemical characteristics of acetylene, the filling process slows down as trailers get close to being filled. Specifically, acetylene cylinders accept gas at a progressively lower rate due to exothermic heat buildup increasing partial pressures of the acetylene/solvent mix within the cylinder. Therefore, in conventional filling systems, the typical approach is to fill trailers in parallel and then let them cool, often overnight, and subsequently finish the filling process the following morning. Thereafter, a few cylinders are removed from the trailer, weighed, and the total weight for the trailer is extrapolated. This intermittent filling procedure is non-conducive to acetylene suppliers that typically make and supply acetylene on a continuous round-the-clock basis. 
   After the cylinders are filled with acetylene, the trailer transports the acetylene to a worksite requiring acetylene gas. Pressure regulating equipment is connected to the trailer to discharge the acetylene from the cylinders. The pressure regulating equipment is typically secured in one location, thereby limiting the supply of acetylene to one specific area of the worksite. Therefore, if acetylene is required at another location, the acetylene gas is transported through an extensive piping arrangement. The use of pipes to transport acetylene to a new location on a worksite can be very costly and creates delays due to piping construction time along with safety concerns due to the volatility of acetylene. 
   There is a need, therefore, for a method to safely and economically fill acetylene into cylinders on a trailer. There is a further need to safely and economically transport acetylene to a worksite. There is yet a further need for a transportable acetylene distribution apparatus that provides a simple and flexible way to provide and use large volumes of compressed acetylene at a worksite. 
   SUMMARY OF THE INVENTION 
   The present invention generally relates to an apparatus and a method for filling tanks with acetylene gas. In one aspect, a method for filling tanks with acetylene gas is proved. The method includes filling a first tank to a first level, thereafter filling a second tank while continuing to fill the first tank. The method further includes restricting the flow of gas to the second tank while continuing to fill the first tank. The method also includes a first and a second transportable source of compressed acetylene. 
   In another aspect, a transportable acetylene distribution apparatus is provided. The acetylene distribution apparatus includes a piping system to act as a fluid conduit for the distribution of acetylene and at least one valve connected to the piping system, whereby the at least one valve controls the flow of acetylene. The acetylene distribution apparatus further includes at least one pressure regulating member connected to the piping system and at least one connector attached to the piping system. The acetylene distribution apparatus also includes a platform, whereby the piping system is disposed on the platform. 
   In yet another aspect, a method for filling cylinders on a trailer system with acetylene gas is provided. The method includes transporting acetylene gas to a trailer fill plant and compressing the acetylene gas by a plurality of compressors. The method also includes moving the compressed acetylene gas through the compressed gas supply line into the piping arrangement. The method further includes placing each trailer assembly into an individual fill bay and subsequently filling the cylinders on the trailer assemblies with acetylene gas. 

   
     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, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. 
     It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
       FIG. 1  illustrates a plan view of a trailer fill plant of an acetylene distribution system. 
       FIG. 2  illustrates a back view of a trailer assembly in accordance with the present invention. 
       FIG. 3  illustrates a top view of the trailer assembly as shown in FIG.  2 . 
       FIG. 4  illustrates a front view of one embodiment of a skid-mounted gas regulating apparatus in accordance with the present invention. 
       FIG. 5  illustrates another embodiment of a gas regulating apparatus in accordance with this present invention. 
       FIG. 6  illustrates unloading of acetylene from a trailer assembly through the skid-mounted apparatus. 
       FIG. 7  illustrates the steps in the acetylene distribution system. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention relates to an acetylene distribution system for safely filling, transporting, and providing acetylene gas to a worksite. The acetylene distribution system includes a trailer filling system  10 , one embodiment of which is shown in a plan view in FIG.  1 . The trailer filling system  10  is controlled by a motor control center  55 . Typically, the motor control center  55  is monitored by an offsite supervisory control and data acquisition system. 
   Generally, low-pressure acetylene enters into the trailer fill plant  10  through a gas pipeline  15 . The amount of acetylene that flows through the pipeline  15 . is measured on a metallic device. Additionally, a flash arrestor  25  is placed on the gas pipeline  15  as a safety device to stop an acetylene flash. Thereafter, the acetylene from the gas pipeline  15  enters into a plurality of compressor input lines  35  to transport the acetylene into several compressors  45  housed in a compressor building  30 . The acetylene typically enters the compressors  45  at 6-8 PSIG and is subsequently compressed to about 360 PSIG. Next, the compressed acetylene exits the compressor building  30  through a plurality of compressor output lines  40 . Thereafter, the compressed acetylene flows into a compressed gas pipeline  50 . 
   As shown in  FIG. 1 , the compressed gas pipeline  50  is connected to a fill building  60 . The fill building  60  comprises of a plurality of fill bays  65 , each of which is sized to accommodate a trailer assembly  100 . Each fill bay  65  includes a scale  70  and a computer  80  to monitor the acetylene entering the bay  65 . The computer  80  is configured to receive signals from the scale  70  to monitor the amount of acetylene entering the fill bay  65 . Additionally, the fill bays  65  are interconnected with each other through an acetylene supply pipe and control valve system  85 . The supply pipe and control valve system  85  are connected to the compressed gas pipeline  50 , thereby enabling compressed acetylene to enter each individual fill bay  65 . The supply pipe and control valve system  85  may be constructed and arranged in a cascading manner to allow flow controlling to each fill bay  65 . 
   The trailer filling system  10  is designed to safely and efficiently fill cylinders on the trailer assembly  100  with acetylene. Typically, each of the fill bays  65  contains the trailer assembly  100  in some stage of the filling process. As the trailer assembly  100  becomes full, the trailer assembly  100  is removed and replaced with an empty trailer assembly  100 . After an empty trailer assembly  100  enters the fill bay  65 , the operator inputs data, such as trailer origination and trailer identification, into the computer  80  and connects the empty trailer assembly  100  to the acetylene supply pipe in the fill bay  65 . Thereafter, the empty trailer assembly  100  is automatically placed into the fill queue as the last one to be filled. 
   The control valve system  85  receives a predefined constant flow rate from the gas pipeline  50  and subsequently distributes the gas to the plurality of fill bays  65 . The control valve system  85  controls the amount of acetylene entering each bay  65  by monitoring the weight of the trailer assembly  100  during the filling process. The control valve system  85  operates in a flow control manner to allow the trailer assembly  100  with the greatest amount of acetylene to receive the largest flow of acetylene from the compressed gas pipeline  50 . As the trailer assembly  100  becomes close to being filled with acetylene, the trailer assembly  100  will accept acetylene at a progressively lower rate due to exothermic heat buildup in each cylinder and rising overall partial pressures of the acetylene/acetone mix. Therefore, as one trailer assembly  100  begins to take less acetylene gas, the next trailer assembly  100  begins to receive more, thereby permitting the total volume through the trailer filling system  10  to remain constant. In this respect, control valve system  85  forces or base loads the acetylene into the trailer assembly  100  with the largest amount of acetylene and swing loads the remaining molecules into the less full trailer assemblies  100 . The scale  70  sends periodic signals to the computer  80 , thereby monitoring the weight of each trailer assembly  100  during the filling process to determine when the trailer assembly  100  is full of acetylene. Thereafter, the full trailer assembly  100  is taken off the supply pipe and the next trailer assembly  100  in line becomes based loaded with acetylene with no change in the overall flow rate of the trailer filling system  10 . 
   The acetylene distribution system further includes a transportable source of compressed acetylene. In one embodiment, the transportable source of compressed acetylene is the trailer assembly  100 . It should be understood that this invention is not limited to this embodiment, but rather the transportable source of compressed acetylene can be ship-based, truck mounted, railcar mounted, or modular for container transportation. 
     FIG. 2  illustrates a back view of the trailer assembly  100  in accordance with the present invention. In the embodiment shown, the trailer assembly  100  includes a trailer  150  and a coupling (not shown) for attaching to a motorized vehicle. In one embodiment, the trailer  150  comprises a bed frame  290  to act as a support member and a plurality of wheels  295  for movement of the trailer assembly  100 . The trailer assembly  100  further includes a connector  105  to connect the trailer assembly  100  directly to a point of use or to a pressure-regulating device (not shown). Attached to the connector  105  is a gauge  110  to indicate the pressure of the acetylene in the trailer assembly  100 . A manual valve  115  is located above the connector  105  to control the flow of acetylene exiting the trailer assembly  100 . 
   As shown in  FIG. 2 , a safety control valve  120  is located at the upper end of the manual valve  115 . The safety control valve  120  works in conjunction with a safety control feed line  175  to provide an automatic shutdown during unsafe conditions. Typically, a hose (not shown) is connected between a pressure regulating apparatus (not shown) and the safety control feed line  175  on the trailer assembly  100 . The safety control feed line  175  acts as an indication device to signal the safety control valve  120  about an unsafe condition that requires the shut down of the unloading process. For example, if the trailer assembly  100  pulls away from the pressure regulating apparatus during the unloading process, the hose will disengage from the safety control feed line  175  causing the safety control valve  120  to close, thereby shutting down the unloading process. In this manner, the safety control valve  120  controls the “breakaway” flow, thereby ensuring the safety of the unloading process of the acetylene distribution system. 
   The trailer assembly  100  further includes a strainer  125  disposed at the upper end of the safety control valve  120 . The strainer  125  acts as a filtering means to prevent any contaminants in the trailer assembly  100  from entering valves  115 ,  120 . A manifold system  130  is connected to the strainer  125 . The manifold system  130  includes a plurality of pipes and acts as a distribution conduit for the acetylene. The manifold system  130  interconnects a plurality of cylinders  135  that house acetylene under pressure. The cylinders  135  are constructed and arranged to hold a predetermined quantity of compressed acetylene. At the upper end of each cylinder  135  is a cylinder valve  140  to control the flow of acetylene entering and exiting the cylinder  135 . Attached to the upper end of each cylinder valve  140  is a high-pressure tubular loop (pigtail)  145  that acts as a fluid conduit between the cylinder  135  and the manifold system  130 . The tubular loop  145  is constructed to be a flexible connection between the cylinder  135  and the manifold system  130 , thereby minimizing the possibility of tubing failure during transport of the compressed acetylene. 
     FIG. 3  illustrates a top view of the trailer assembly  100  as shown in FIG.  2 . The trailer  150  is constructed and arranged to handle the plurality of cylinders  135  of compressed acetylene for transport from one point to another in a safe and efficient manner. Transportation regulations govern the weight of a trailer system. The trailer  150  of this embodiment is constructed without the standard center beams, thereby reducing the weight of the trailer  150  and allowing a larger quantity of cylinders  135  to be transported within weight regulations. In the embodiment shown, the trailer  150  is constructed of sidewall structural support members  170  that form a truss which replaces the center beams and distributes the weight of the cylinders  135  over the center axis portion of the trailer  150 . As further shown, a plurality of support members  155  are connected to the sidewall support members  170  and the bed frame  290  to aid in the distribution of the load. Additionally, the length of the trailer  150  may be constructed to allow the maximum quantity of cylinders  135  to be transported within transportation regulations. 
   As shown, the cylinders  135  are nested in a plurality of sections  160  (illustratively shown) and a plurality of rows  165  (illustratively shown). Each section  160  is arranged to maximize the quantity of cylinders  135  within a predetermined space and to distribute the weight of the cylinders  135  over the outside edges of the trailer  150 . The sections  160  are divided by the plurality support members  155  to secure the cylinders  135  within the section  160  during transport. In addition, the sidewall support members  170  on the outer edges and walkway members  180  form the rows  165 . The members  170 ,  180  secure the cylinders  135  within the row  165  during transport. As further depicted, a walkway  285  is located along the center of the bed frame  290  to ensure easy access to cylinders  135 . 
   The acetylene distribution system further includes transportable gas regulating apparatus  200  to regulate the acetylene during the unloading process from the trailer assembly  100 .  FIG. 4  illustrates a front view of one embodiment of the skid-mounted gas regulating apparatus  200  in accordance with the present invention. The apparatus  200  is used to reduce the pressure of the acetylene and act as a conduit between the trailer assembly  100  and the point of use on the worksite. The apparatus  200  includes a platform  205  to provide support for the components of the apparatus  200 . The platform  205  also permits the apparatus  200  to be moved as a complete unit from one point to another. A plurality of lugs  210  is connected to the platform  200  to aid in the movement of the apparatus  200 . Typically, chains with hooks are connected to the lugs  210  allowing the apparatus  200  to be lifted by mechanical equipment and moved from one point to another. In this respect, the transportable gas regulating apparatus  200  is a portable regulating device for the acetylene distribution system. 
   As illustrated in  FIG. 4 , the apparatus  200  includes a ball valve  235  and a gate valve (not shown). A pressure switch  230  and a regulator  215  are located at the front portion of the apparatus  200 . As shown, an arm  220  is disposed near the regulator  215 . The arm  220  is extendable to connect to the trailer assembly  100  during the unloading process. As further shown, a plurality of interconnected pipes  265  are used to transport the acetylene throughout the apparatus  200 . The pipes  265  connect to a header  245  and a flash arrestor  280  as shown. All the components are securely fastened to the platform  205 , thereby allowing the apparatus  200  to act as one transportable unit. 
   In another embodiment, the trailer assembly  100  can be connected directly to the point of use through a regulator (not shown). In this embodiment, the apparatus  200  is not required to unload the acetylene gas. This embodiment is useful when the point of use requires only a single unit of compressed acetylene. 
     FIG. 5  illustrates another embodiment of a transportable gas regulating apparatus  300  in accordance with this present invention. The transportable gas regulating apparatus  300  contains similar components as the transportable gas regulating apparatus  200  shown in FIG.  4 . In a similar manner to the apparatus  200 , the apparatus  300  is used to reduce the pressure of the acetylene and act as a conduit between the trailer assembly  100  and the point of use. However, the principle difference between apparatus  200  and apparatus  300  is that apparatus  300  is permanently mounted on a trailer  305 . The trailer  305  permits the apparatus  300  to be transported down the highway and throughout the worksite by a truck (not shown), thereby increasing mobility of the apparatus  300 . 
   In operation, the trailer assembly  100  is brought to a predetermined location to fill the cylinders  135  as discussed in FIG.  1 . In the preferred embodiment, the transportable source of compressed acetylene is the trailer assembly  100  as illustrated in  FIGS. 2 and 3 . After the cylinders  135  are filled with compressed acetylene, the trailer assembly  100  is taken to a point of use at the worksite. The point of use can be a manufacturing process, a reservoir for storage, a point of consumption, gas transport infrastructure, or any other location that requires compressed acetylene. In the preferred embodiment, the transportable gas regulating apparatus  200  or the trailer mounted apparatus  300  is located at a predetermined location at the worksite to act as a fluid conduit between the trailer assembly  100  and the point of use. The apparatus  200 ,  300  is connected at one end to the point of use and the other end to the connector  105  on the trailer assembly  100 . 
   In one embodiment shown in  FIG. 6 , the acetylene is unloaded from the trailer assembly  100  through the skid-mounted apparatus  200 . The skid-mounted apparatus  200  may unload up to three trailer assemblies  100  simultaneously. For clarity purposes,  FIG. 6  illustrates the unloading of two trailer assemblies  100 . However, it should be noted in other embodiments any number of trailer assemblies  100  could be unloaded simultaneously. Generally, the arm  220  is attached to the connector  105  on the trailer assembly  100 . As shown on  FIG. 2 , the valve  115  is used to control the amount of acetylene output from the trailer assembly  100 . To start the movement of acetylene, valve  115  is opened allowing acetylene to flow from the individual cylinders  135  through the valve  140  and the pigtail  145  into the manifold  130 . The manifold system  130  fluidly connects the cylinders  135  together and directs the acetylene toward the valve  115 . The acetylene passes through the strainer  125  removing any contaminants from the trailer assembly  100  and subsequently exits out the connector  105  into the apparatus  200 . The gauge  110  indicates the pressure of acetylene exiting the trailer assembly  100 . As the acetylene flows through the various components of the apparatus  200 , the pressure of the acetylene is reduced to an acceptable pressure for the point of use. The supply of acetylene exiting the trailer assembly  100  is self-regulating, wherein the need at the point of use determines the quantity of acetylene exiting the trailer assembly  100 . 
   Referring back to  FIG. 6 , the low-pressure acetylene subsequently exits out the transportable gas regulating apparatus  200  through a pipe  240  that is connected to the header  245 . The pipe  240  directs the low-pressure acetylene to the point of use. In the event of an acetylene fire during the unloading process, a deluge system may provide high-pressure water to quench the fire. The deluge system includes a deluge gate valve  225 , a deluge riser  275 , deluge header  250 , and a connection flange  270  at the upper end of the apparatus  200 . 
     FIG. 7  illustrates the steps in the acetylene distribution system. As illustrated, the acetylene gas is compressed and placed in a gas pipeline. Thereafter the gas in the pipeline enters the filling system. The filling system controls the amount of acetylene gas entering each trailer assembly. During the fill process, the cylinders on the trailer assembly are filled with acetylene. The weight of the acetylene entering the cylinders is monitored through a computer and scale arrangement. The computer is configured to receive a signal from the scale when the cylinders on the trailer assembly are full of acetylene. Thereafter, the full trailer assembly is removed and replaced with an empty trailer assembly. Subsequently, the full trailer assembly is transported to the point of use. Next, the trailer assembly is connected to a transportable gas regulating apparatus. At this point, the acetylene gas in the trailer assembly is discharged through the transportable gas regulating apparatus to the point of use. 
   While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.