Patent Description:
In steelmaking and continuous casting processes, a ladle is used for receiving, refining and transporting molten steel. A purging plug is provided at a bottom of the ladle and is connected to an argon gas utility line. During the steelmaking process, argon gas may be supplied from the utility line to the purging plug, and hence a bubbling process of molten steel may be performed. In this bubbling process, it may be possible to stir the molten steel, adjust its components, float its inclusions, and control its temperature.

On the other hand, when the bubbling process of molten steel is completed, the purging plug is separated from the argon gas utility line, and the ladle is conveyed to the next process. At this time, the molten steel in the ladle penetrates into the purging plug and solidifies. Therefore, conventionally, a gas pipe having a detachable structure was installed on a trolley for carrying the ladle, and gas was supplied to the purging plug via the gas pipe while the ladle was being conveyed.

However, in such conventional structure, there is a problem in that argon gas is excessively supplied to the purging plug because argon gas is supplied under the same pressure as the pressure in the bubbling process from the argon gas utility line even during the movement of the trolley. And there is a problem in that it is difficult to supply argon gas to the purging plug after lifting the ladle from the trolley.

The technology underlying the present invention is published in the following patent documents.

The present invention provides an apparatus and method for processing a melt which is capable of effectively preventing the penetration of a melt into an injection unit over a long period of time.

According to an embodiment of the present invention, an apparatus for processing a melt includes a container unit having an inner space to receive a melt; an injection unit mounted on a lower portion of the container unit to inject gas into the melt in the container unit; a storage unit mounted on the container unit and filled with gas; a supply unit installed in the container unit to connect the injection unit and the storage unit and having a pressure regulator for regulating a supply pressure of the gas and a flow regulator for regulating a supply flow rate of the gas under the adjusted supply pressure, and a weight adjustment unit mounted on an outer surface of the container unit at a position opposite to the storage unit in a horizontal direction with the container unit interposed therebetween, wherein the weight adjustment unit is installed to be at least partially movable in a horizontal direction along an outer surface of the container unit to adjust the center of gravity, the weight adjustment unit includes: a holding bar; a weight; an actuator controlled by a control unit and configured to move the holding bar depending on an amount of gas filled in the storage unit; a guide rail; and wherein the position of the weight is adjusted in a front-rear direction depending on the movement of the holding bar.

The supply unit may include a pipe extending along an outer surface of the container unit and connecting the injection unit and the storage unit; and a safety valve mounted on the pipe, wherein the pressure regulator may be mounted on the pipe between the safety valve and the injection unit, and the flow regulator may be mounted on the pipe between the pressure regulator and the injection unit.

The supply unit may include a first blocking valve mounted on the pipe between the safety valve and the pressure regulator; a discharge valve mounted on the pipe between the first blocking valve and the safety valve; and a second blocking valve mounted on the pipe between the pressure regulator and the flow regulator.

A plurality of storage units may be provided, and a part of the pipe may be branched into a plurality of sub-pipes, and each of sub-pipes may be connected to each storage unit.

The storage unit may include a replaceable pressure container connected to the pipe and filled with gas; a partially openable protective container mounted on an outer surface of the container unit to receive the pressure container; an anti-shattering plate formed to cover an upper surface of the protective container; and a holding plate protruding from an inner surface of the protective container and being in contact with the pressure container.

The pressure container may have a convex upper portion, a plurality of holding plates may be provided, and at least one holding plate may be in contact with the convex upper portion of the pressure container to restrict the vertical movement of the pressure container.

The rest of the holding plates may be in contact with a side surface of the pressure container to restrict the horizontal movement of the pressure container.

According to an embodiment of the present invention, a method for processing a melt includes the steps of providing a container unit that is movable together with a storage unit filled with gas; conveying the container unit containing the melt from a first position to a second position; supplying gas to an injection unit mounted on a lower portion of the container unit to inject the gas into the melt in the container unit; adjusting a supply pressure of the gas supplied to the injection unit; adjusting a supply flow rate of the gas under the adjusted supply pressure; preventing the center of gravity of the container unit from being biased by applying a weight to a side opposite to the storage unit about the container unit; and moving the action point of the weight toward the storage unit depending on an amount of gas consumed using a weight adjustment unit, wherein the weight adjustment unit is mounted on an outer surface of the container unit at a position opposite to the storage unit in a horizontal direction with the container unit interposed therebetween, and wherein the weight adjustment unit is installed to be at least partially movable in a horizontal direction along an outer surface of the container unit to adjust the center of gravity, , wherein while the providing of the container unit, the conveying of the container unit, the supplying of the gas, the adjusting of the supply pressure of the gas, and the adjusting of the supply flow rate of the gas are performed, a weight is used to apply a weight to a side opposite to the storage unit about the container unit so that the center of gravity of the container unit is prevented from being biased, and an actuator controlled by a control unit is used to move an action point, to which the weight is applied, depending on an amount of gas consumed in the storage unit.

Adjusting the pressure may include reducing the supply pressure to a reference pressure that is lower than an internal pressure of the utility line in at least one of the first and second positions and higher than the melt pressure.

Adjusting the pressure may include reducing the supply pressure to a reference pressure that is lower than a filling pressure of the storage unit and higher than the melt pressure.

Adjusting the flow rate may include increasing or decreasing the supply flow rate such that the gas follows a preset reference flow rate while maintaining the supply pressure.

The melt may include at least one of molten steel and slag.

According to the foregoing embodiments of the present invention, by using the storage unit separated from the utility line, gas can be supplied to the injection unit under a desired pressure and flow rate over a long time. In addition, when the pressure of the storage unit is lowered by consuming gas filled in the storage unit, the supply pressure and the supply flow rate of gas may be maintained at a desired reference value by using the pressure regulator and the flow regulator. In this manner, by first adjusting the supply pressure of gas and then adjusting the supply flow rate of gas under the adjusted pressure, the supply pressure and the supply flow rate of gas may be stably maintained over a long time. Thus, while the container unit repeats the entire process cycle of steelmaking and continuous casting processes several times, it is possible to effectively prevent the melt from penetrating into the spraying unit directly exposed to the melt over a long time. As a result, the service life of the gas injection unit may be increased, and the container unit may be smoothly operated, thereby improving the productivity of the steelmaking and continuous casting processes.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments disclosed below and will be implemented in a variety of different forms. Only the embodiments of the present invention are provided to complete the disclosure of the present invention and to completely inform those of ordinary skill in the art the scope of the invention. The drawings may be exaggerated to explain the embodiments of the present invention, and like reference numerals in the drawings refer to the same elements.

An apparatus and method for processing a melt according to the present invention may be applied to various melt processing processes in various industrial fields. Hereinafter, the present invention will be described in detail with respect to a ladle which is used for receiving, refining, and transporting molten steel in steelmaking and continuous casting processes of steel industry.

<FIG> is a schematic view showing an apparatus for processing a melt according to an embodiment of the present invention, and <FIG> are a plan view showing upper and lower portions of a container unit according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, an apparatus for processing a melt according to an embodiment of the present invention will be described in detail.

According to an embodiment of the present invention, an apparatus for processing a melt includes a container unit <NUM> having an inner space to receive a melt M; an injection unit <NUM> mounted on a lower portion of the container unit <NUM> to inject gas into the melt M in the container unit <NUM>; a storage unit <NUM> mounted on the container unit <NUM> and filled with gas; and a supply unit <NUM> installed in the container unit <NUM> to connect the injection unit <NUM> and the storage unit <NUM> and having a pressure regulator <NUM> for regulating the supply pressure of the gas and a flow regulator <NUM> for regulating the supply flow rate of the gas under the adjusted supply pressure.

The melt M may include at least one of molten steel and molten slag, but is not limited to. Also, the gas may include an inert gas such as argon, but is not limited to.

The container unit <NUM> may receive the melt M therein. The container unit <NUM> may be used for receiving, refining, and transporting molten steel in steelmaking and continuous casting processes, and may be used for receiving and transporting slag. The container unit <NUM> may include a container body <NUM>, a protrusion member <NUM>, a locking member <NUM>, a support member <NUM>, and a discharge member <NUM>.

The container body <NUM> may have a cylindrical shape, for example. The container body <NUM> may have an inner space and an openable upper portion. The melt M may be received in the inner space of the container body <NUM>. The container body <NUM> may have a bottom plate and a side wall. The bottom plate may be any shape, for example a disk shape and may extend in a horizontal direction. In this case, the horizontal direction may include a left-right direction and a front-rear direction. The side wall may be a hollow cylindrical shape and may extend in a vertical direction. In addition, the side wall may be mounted around an upper surface edge of the bottom plate. The shape and structure of the container body <NUM> are not limited thereto; the container body <NUM> may have various shape and structure.

The protrusion member <NUM> may protrude from an outer circumferential surface of the side wall of the container body <NUM> and may extend along the perimeter of the outer circumferential surface. A pair of locking members <NUM> may be provided to be spaced apart from each other in a horizontal direction and may be mounted on both upper sides of the side wall of the container body <NUM>. Also, the locking member <NUM> may be coupled to a main winding hook (not shown) of a crane (not shown). The container unit <NUM> may be supported and lifted on the main winding hook by the locking member <NUM>. On the other hand, a tilting arm (not shown) may be provided on a lower surface of the bottom plate of the container body <NUM> and may be coupled to a slave winding hook (not shown) of the crane. The container unit <NUM> may be tilted by pulling the tilting arm upward with the slave winding hook.

A plurality of support members <NUM> may be provided to be spaced apart from each other in a horizontal direction and may be mounted on a lower surface edge of the bottom plate of the container body <NUM>. When the container body <NUM> is seated on a trolley (not shown) and a ladle turret (not shown), a desired separation space can be obtained beneath the bottom plate of the container body <NUM> by the support member <NUM>. The discharge member <NUM> may be mounted on an upper end of the side wall of the container body <NUM> between the pair of locking members <NUM>. The discharge member <NUM> and the tilting arm may be spaced apart from each other in a front-rear direction. The discharge member <NUM> may be positioned in front of the locking members <NUM>. The discharge member <NUM> may be provided with a discharge passage in a concave shape on an upper surface thereof. The discharge passage may extend in the front-rear direction. When the container unit <NUM> is tilted, the melt M may be discharged to the front of the container body <NUM> through the discharge passage. That is, the term front may refer to a direction in which the melt M is discharged from the container unit <NUM>.

<FIG> is a side view of the apparatus for processing a melt according to an embodiment of the present invention, <FIG> is a rear view of the apparatus for processing a melt according to an embodiment of the present invention, and <FIG> is a conceptual diagram for explaining a supply unit according to an embodiment of the present invention.

Now, an injection unit, a storage unit, and a supply unit of an apparatus for processing a melt according to an embodiment of the present invention will be described with reference to <FIG>.

Referring to <FIG>, the injection unit <NUM> may be mounted on a lower portion of the container body <NUM> to inject gas into the container body <NUM>. For example, the injection unit <NUM> may be mounted through the bottom plate of the container body <NUM> in a vertical direction. In addition, the injection unit <NUM> may have an upper surface exposed inside the container body <NUM>. The injection unit <NUM> may include a porous refractory material. The injection unit <NUM> may be referred to as a purging plug or a bottom plug, for example. Also, the injection unit <NUM> may be referred to as a nozzle or a bottom blowing nozzle. The injection unit <NUM> may be connected to the storage unit <NUM> via the supply unit <NUM>, and gas filled in the storage unit <NUM> may be supplied to the injection unit <NUM>. The gas may be injected into the melt M in the container unit <NUM> from the injection unit <NUM>. When the container unit <NUM> is used for refining the melt M, a relatively large amount of gas may be supplied to the injection unit <NUM>. When the container unit <NUM> is used for receiving and transporting the melt M, a relatively small amount of gas may be supplied to the injection unit <NUM>. A large amount of gas supplied to the injection unit <NUM> may bubble molten steel in the melt M. A small amount of gas supplied to the injection unit <NUM> serves to prevent the melt M from penetrating into the injection unit <NUM>, so that it is suitable for clean bubbling that does not occur naked molten metal on an upper surface of the melt M. The supply of gas is performed by the storage unit <NUM> and the supply unit <NUM>, and the operation of the supply unit <NUM> may be controlled by a controller (not shown).

The storage unit <NUM> may be supported by the container unit <NUM>. The storage unit <NUM> may move together with the container unit <NUM>. The storage unit <NUM> serves to continuously, for example constantly supply gas to the injection unit <NUM> while the container unit <NUM> repeats the entire process cycle of steelmaking and continuous casting processes several times. That is, the storage unit <NUM> serves to continuously supply gas to the injection unit <NUM> and prevent the melt M from penetrating into the injection unit <NUM> while the container unit <NUM> repeatedly performs a series of processes including converter steel tapping, bubbling, secondary refining, continuous casting, and slag exclusion. To this end, the storage unit <NUM> may be configured to store a sufficient amount of gas and to stably supply the stored gas to the injection unit <NUM> over a long time. Also, the storage unit <NUM> may be configured to safely protect the stored gas from a high temperature of the melt M and shattering matters. The storage unit <NUM> may include a protective container <NUM>, a pressure container <NUM>, an anti-shattering plate <NUM>, and a holding plate <NUM>.

Referring to <FIG> and <FIG>, the protective container <NUM> may be spaced apart from the discharge member <NUM> in a front-rear direction. The protective container <NUM> may be spaced apart from the rear of the discharge member <NUM>. In addition, the locking member <NUM> may be positioned between the protective container <NUM> and the discharge member <NUM>. The protective container <NUM> may be formed, for example in a cylindrical shape with an empty interior to receive the pressure container <NUM>. However, the protective container <NUM> may have various shapes depending on the shape of the pressure container <NUM>. The pressure container <NUM> may also have various shapes as long as it does not interfere with surrounding equipment such as cranes and hooks. The protective container <NUM> may be formed to be larger than the pressure container <NUM> such that at least a portion of its inner surface may be spaced apart from the pressure container <NUM>. The protective container <NUM> may be mounted on an outer surface of the container unit <NUM>.

That is, the protective container <NUM> may be mounted on at least one of the side wall and the protrusion member <NUM> of the container body <NUM>. Specifically, the protective container <NUM> may be mounted on the protrusion member <NUM> to be spaced rearward from the side wall of the container body <NUM>. The protective container <NUM> may be mounted on the side wall of the container body <NUM> between the protrusion members <NUM> in a vertical direction. The protective container <NUM> serves to protect the pressure container <NUM> from a high temperature of the melt M and shattering.

The protective container <NUM> may be partially opened and closed to facilitate the receiving of the pressure container <NUM>. To this end, the protective container <NUM> may have a plurality of detachable protective bodies. That is, the protective container <NUM> may be formed from separable first and second protective bodies <NUM> and <NUM>. Each of the protective bodies <NUM> and <NUM> may have a shape in which a cylinder is cut in half in a vertical direction. Thus, one complete cylindrical shape can be obtained by combining these protective bodies <NUM> and <NUM>. As the protective bodies <NUM> and <NUM> have a cylindrical shape, a structural interference between the protective bodies <NUM> and <NUM> and surrounding equipment can be minimized or prevented.

The protective bodies <NUM> and <NUM> may be arranged in a front-rear direction, any one of the protective bodies may be mounted on the container unit <NUM>. Specifically, the second protection body <NUM> may be mounted on the protrusion member <NUM>, and the first protection body <NUM> may be rotatably mounted on one side of the second protection body <NUM> in a left-right direction. In addition, the second protective body <NUM> may be mounted on the side wall of the container body <NUM> between the protrusion members <NUM>, and the first protective body <NUM> may be rotatably mounted on one side of the second protective body <NUM> in a left-right direction. Alternatively, the first protective body <NUM> may be mounted on the protrusion member <NUM> or the container body <NUM>, and the second protection body <NUM> may be rotatably mounted on the first protection body <NUM>.

The first protective body <NUM> may be rotate the other side thereof about one side in a left-right direction to open and close the interior of the protective container <NUM>. The other side of the first protection body <NUM> in the left-right direction may be provided with a desired fastening member (not shown) to couple the first protection body <NUM> to the second protection body <NUM>. The fastening member may have various structures to facilitate the opening and closing of the protective container <NUM>.

The pressure container <NUM> may be connected to a pipe <NUM> of the supply unit <NUM> and may be filled with high pressure gas. The pressure container <NUM> may be replaceable. Here, the term replaceable pressure container <NUM> means that the gas-consumed pressure vessel <NUM> may be replaced with a new pressure container <NUM> filled with high pressure gas <NUM> when gas filled in the pressure container <NUM> was consumed by a predetermined amount.

The pressure container <NUM> may be formed in a cylindrical shape that extends in a vertical direction and has a desired diameter in a horizontal direction. However, the pressure container <NUM> may have various extension directions and shapes. The pressure container <NUM> may be housed in the protective container <NUM>. The pressure container <NUM> may be filled with high pressure gas. Here, the term high pressure may refer to a pressure higher than the pressure of the utility line as described below. The pressure container <NUM> may also be referred to as a gas storage container.

The pressure container <NUM> may be separated from a utility line provided in at least one of steelmaking and continuous casting facilities and may be independently used. That is, the pressure container <NUM> may be a component arranged separately from the utility line. The pressure container <NUM> may be filled with gas by using a separate filling means (not shown) under a pressure higher than the pressure inside the utility line. The supply pressure of gas supplied from the pressure container <NUM> through the supply unit <NUM> to the injection unit <NUM> may be lower than the pressure of the utility line. Here, the term pressure of the utility line may refer to a supply pressure of gas flowing inside the utility line.

The pressure container <NUM> may have the capacity of about <NUM>. However, the capacity of the pressure container <NUM> may vary depending on the size of the container body <NUM>, the total time during which a series of processes including converter steel tapping, bubbling, secondary refining, continuous casting and slag exclusion are performed, and the like. The gas filling pressure of the pressure container <NUM> may be <NUM> to <NUM> times, preferably <NUM> to <NUM> times higher than the gas supply pressure of the utility line. That is, the gas filling pressure of the pressure container <NUM> may be, for example in the range of <NUM> to <NUM> bar. Here, the term filling pressure means a pressure of gas supplied to the pressure container <NUM> when gas is filled in the pressure container <NUM>. When the pressure container <NUM> is fully filled with gas, the pressure inside the pressure container <NUM> may be equal to the filling pressure. That is, the term filling pressure means the gas pressure of the pressure container <NUM> at the time when the filling of the pressure container <NUM> is completed. The gas pressure inside the pressure container <NUM> during the operation of the pressure container <NUM> is referred to as an internal pressure. The filling pressure of the pressure container <NUM> may be significantly higher than about <NUM> bar which is the gas supply pressure of the utility line provided in steelmaking and continuous casting facilities. Thus, the relatively high gas filling pressure of the pressure container <NUM> allows for a large amount of gas to be filled into the pressure container <NUM>.

The internal pressure endured by the pressure container <NUM> may be higher than the filling pressure of the pressure container <NUM>. Hence, when the pressure container <NUM> is filled with gas under the pressure of <NUM> bar, for example, the pressure container <NUM> may be stably used. Even when the pressure container <NUM> is exposed to high temperature radiant heat temporarily or for a long time and the temperature of the pressure container <NUM> is increased, the pressure container <NUM> may stably accommodate the volume expansion of gas due to the increased temperature. In this case, the internal pressure endured by the pressure container <NUM> may be referred to as, for example a maximum internal pressure or an acceptable pressure of the pressure container <NUM>.

The pressure container <NUM> may be housed in the protective container <NUM> in a state that gas is filled under the filling pressure of <NUM> to <NUM> bar, and may be connected to the pipe <NUM> of the supply unit <NUM> inside the protective container <NUM>. The pressure container <NUM> may supply gas to the injection unit <NUM> via the pipe <NUM>. In this case, the supply pressure and flow rate of gas from the pressure container <NUM> to the injection unit <NUM> may be sequentially controlled by the pressure regulator <NUM> and the flow regulator <NUM> of the supply unit <NUM>. When the pressure of gas filled in the pressure container <NUM>, that is, the internal pressure of the pressure container <NUM> is close to the supply pressure of gas supplied to the injection unit <NUM>, the pressure container <NUM> may be replaced with a new pressure container <NUM> having gas filled under the filling pressure of <NUM> to <NUM> bar, and the new pressure container <NUM> may be housed in the protective container <NUM>.

The anti-shattering plate <NUM> may be formed to cover an upper surface of the protective container <NUM>. Thus, high-temperature radiant heat and shattering matters generated by the melt M in the container body <NUM> may be blocked by the anti-shattering plate <NUM> before the protective container <NUM> is contaminated. The pressure container <NUM> may be primarily protected from heat and shattering matters by the anti-shattering plate <NUM>, and secondarily protected by the protective container <NUM>. As such, the storage unit <NUM> may safely and doubly protect the pressure container <NUM> using the anti-shattering plate <NUM> and the protective container <NUM>.

For example, while the container unit <NUM> performs a series of processes from converter steel tapping to continuous casting and slag exclusion, the melt M may be discharged several times from the container unit <NUM>. During these processes, a strong splash is generated and attached to the container unit <NUM>, resulting in forming a fagot. The anti-shattering plate <NUM> may block the splash from reaching the protective container <NUM> from an upper side of the protective container <NUM> and may prevent the fagot from being attached to the protective container <NUM>.

The anti-shattering plate <NUM> may be detachable. It may also be replaced earlier than the protective container <NUM>. That is, the entire storage unit <NUM> can be maintained in a clean state without replacing the entire storage unit <NUM>, only replacing the anti-shattering plate <NUM> as needed.

The holding plate <NUM> serves to stably support the pressure container <NUM> in the protective container <NUM>. That is, in order to suppress or prevent heat transfer from the protective container <NUM> to the pressure container <NUM>, the inner side and upper surfaces of the protective container <NUM> are spaced apart from the outer side and upper surfaces of the pressure container <NUM>. At this time, the holding plate <NUM> in contact with the pressure container <NUM> may hold the pressure container <NUM> in the protection container <NUM>. For example, the holding plate <NUM> may be formed in a ring shape such that an inner circumferential surface may be in contact with the pressure vessel <NUM> and an outer circumferential surface may be supported on an inner side surface of the protective container <NUM>. In this case, the holding plate <NUM> may be formed of a plurality of separate members, for example two separate members wherein some may be supported on the first protection body <NUM> and the rest may be supported on the second protection body <NUM>. When the first protection body <NUM> is coupled to the second protection body <NUM>, said two separate members may be coupled to form one holding plate <NUM>.

The holding plate <NUM> may protrude from an inner surface such as an inner side surface of the protective container <NUM> and may be in contact with an outer surface such as an outer side surface and the outer upper surface of the pressure container <NUM>. The pressure container <NUM> may have an upper portion convex upward. Thus, an outer upper surface of the pressure container <NUM> may be formed to be convex upward. A plurality of holding plates <NUM> may be provided, and at least one holding plate, for example the first holding plate <NUM> may be in contact with the convex upper portion, that is, the outer upper surface of the pressure container <NUM> to restrict the vertical movement of the pressure container. As described above, the first holding plate <NUM> may be formed of two separate members wherein one may be supported on the first protection body <NUM> and the other may be supported on the second protection body <NUM>.

Meanwhile, the remainder holding plates excluding the first holding plate <NUM> among the plurality of holding plates <NUM> is referred to as the second holding plate <NUM>. The number of the second holding plate <NUM> may be at least one. The second holding plate <NUM> may be spaced apart from a lower side of the first holding plate <NUM> to be in contact with an inner side surface of the pressure container <NUM>, thereby restricting the horizontal movement of the pressure container <NUM>. The second holding plate <NUM> may also be formed of two separate members wherein one may be supported on the first protection body <NUM> and the other may be supported on the second protection body <NUM>.

The holding plate <NUM> allows a separation space to be formed and maintained between the protective container <NUM> and the pressure container <NUM>, and hence the pressure container <NUM> may be stably held in the protective container <NUM>.

For example, the container unit <NUM> may be tilted from an upright state to <NUM> to <NUM>° during slag exclusion. At this time, the holding plate <NUM> may prevent the pressure container <NUM> from moving in left-right and vertical directions inside the protective container <NUM>. Thus, the pressure container <NUM> may be prevented from being damaged by colliding with the protection container <NUM>.

The storage unit <NUM> may include a pipe installation hole <NUM> and a blowhole <NUM>. The pipe installation hole <NUM> may be formed to pass through an upper or lower portion of the first protection body <NUM>. Also, the pipe <NUM> of the supply unit <NUM> may be disposed to pass through the pipe installation hole <NUM>.

The blowhole <NUM> may be formed to pass through a lower or upper portion of the first protection body <NUM>. Air may be introduced from the outside of the protective container <NUM> to the inside through the blowhole <NUM>. The number of the blowhole <NUM> may be at least one. Also, a blower (not shown) may be provided around the blowhole <NUM> for forced inflow of air. The blower may be supported by the protective container <NUM>.

The protective container <NUM> may be provided with at least one of a heat blocking member and a cooling channel (both not shown) on the inner surface thereof. In this case, the separation space formed between the protective container <NUM> and the pressure container <NUM> may be used as an installation space for at least one of the heat blocking member and the cooling channel.

The heat blocking member may include a refractory heat insulating material having a heat shielding function even at a temperature of about <NUM> or higher. The heat blocking member may be manufactured by melting and fiberizing a refractory material including silica and alumina, followed by forming or weaving the resulting substance into a desired shape. Such heat blocking member may be referred to as, for example Cerakwool. The heat blocking member may be formed to encase at least one of the inner surface of the protective container <NUM> and the outer surface of the pressure container <NUM>. Thus, radiant heat transferred from the melt M in the container unit <NUM> to the protective container <NUM> may be slowly transferred to the pressure container <NUM>, or such heat transfer may be blocked. The heat blocking member may suppress or prevent an increase in the temperature of the pressure container <NUM>, thereby suppressing or preventing an increase in the internal pressure of the pressure container <NUM>.

Also, the cooling channel may be installed between the protective container <NUM> and the pressure container <NUM> to be at least partially in contact with or exposed to the pressure container <NUM>. The cooling channel may be connected to the blowhole <NUM> or a utility line (not shown) for supplying a refrigerant. Alternatively, the separation space between the protective container <NUM> and the pressure container <NUM> may be used as a cooling channel as it is. It is possible to suppress or prevent an increase in the temperature of the pressure container <NUM> by the air or refrigerant supplied to the cooling channel. As a result, an increase in the internal pressure of the pressure container <NUM> may be suppressed or prevented.

A plurality of storage units <NUM> may be provided at the rear of the container body <NUM>. For example, two storage units <NUM> may be provided to be spaced apart from each other in a left-right direction, and may be supported by the protrusion member <NUM> at the rear of the locking member <NUM>, or on the side wall of the container body <NUM> between the protrusion members <NUM>. However, the number of the storage unit <NUM> may vary. The plurality of storage units <NUM> allows gas to be supplied to the injection unit <NUM> over a long time, and hence the integrity of the injection unit <NUM> can be maintained over a long time. The integrity may be determined depending on the degree of penetration of the melt M into the injection unit <NUM>. That is, the integrity may be considered to be maintained in a state that the melt M does not penetrate into the injection unit <NUM> or a state that a small amount of the melt M penetrates the injection unit <NUM> enough to operate the injection unit <NUM> smoothly.

As such, by using the plurality of storage units <NUM>, for example, even while the container unit <NUM> waits for a long time after slag exclusion, the integrity of the injection unit <NUM> may be maintained. Alternatively, a single storage unit <NUM> may be provided at the rear of the container body <NUM>.

Referring to <FIG> and <FIG>, it is shown the supply unit <NUM> extending along an outer surface of the container unit <NUM>. The supply unit <NUM> may include a pipe <NUM> with an end being connected to the injection unit <NUM> and the other end being connected to the storage unit <NUM>, a safety valve <NUM> mounted on the other end of the pipe <NUM>, a pressure regulator <NUM> mounted on the pipe <NUM> between the safety valve <NUM> and the injection unit <NUM>, and a pressure regulator <NUM>, and a flow regulator <NUM> mounted on the pipe <NUM> between the pressure regulator <NUM> and the injection unit <NUM>. A part of the pipe <NUM> may be branched into a plurality of sub-pipes 410a, and each of sub-pipes 410a may be connected to each storage unit <NUM>. Specifically, the other end of the pipe <NUM> may be branched into a plurality of sub-pipes 410a. Also, the plurality of sub-pipes 410a may be respectively connected to the plurality of storage units <NUM> on a one-to-one basis.

The pipe <NUM> may have one end extending along a lower surface of the bottom plate of the container body <NUM> to connect the injection unit <NUM> and the storage unit <NUM>, and may be connected to a lower portion of the injection unit <NUM>. Each of sub-pipes 410a formed at the other end of the pipe <NUM> may be installed to pass through the protective container <NUM>, and may be connected to the pressure container <NUM>.

On the other hand, when a single storage unit <NUM> is provided, the other end of the pipe <NUM> may not be branched. That is, the other end of the pipe <NUM> may be installed to pass through the protective container <NUM> and may be directly connected to the pressure container <NUM>.

A connection pipe may extend along a side wall of the container body <NUM> to connect one end of the pipe <NUM> and the other end. The pressure regulator <NUM> and the flow regulator <NUM> may be respectively mounted on the connection pipe.

The safety valve <NUM> may be mounted on the pipe <NUM>. Specifically, the safety valve <NUM> may be mounted on the sub-pipes 410a at the outside of the protective container <NUM>. The safety valve <NUM> may automatically be opened to discharge gas to the outside when the internal pressure of the pressure container <NUM> increase to a desired pressure that is smaller than the internal pressure endured by the pressure container <NUM>, that is, an acceptable pressure. The safety valve <NUM> may be blocked after a desired amount of gas is discharged over a period of time. When a single storage unit <NUM> is used, the safety valve <NUM> may be mounted on the other end of the pipe <NUM> at the outside of the protective container <NUM>.

The pressure regulator <NUM> may be located upstream the flow regulator <NUM> in a direction of gas flow from the pressure container <NUM> to the injection unit <NUM>. The flow regulator <NUM> may be located downstream the pressure regulator <NUM> in the direction of gas flow. Here, the term upstream means a region over which gas relatively first passes, and the term downstream means a region over which the gas relatively later passes.

The pressure regulator <NUM> may include a pressure reducing valve. The pressure regulator <NUM> may constantly maintain an output pressure at a desired pressure smaller than an input pressure. The input pressure refers to a gas pressure input to the pressure regulator <NUM> which is led from the pressure container <NUM> to the pipe <NUM>. The output pressure refers to a gas pressure output to the inside of the pipe <NUM> which passes through the pressure regulator <NUM>. The output pressure may be the supply pressure of gas from the pressure container <NUM> to the injection unit <NUM>.

The pressure regulator <NUM> may maintain constantly the output pressure even when the pressure decreases due to a decrease in the gas filling capacity of the pressure container <NUM>. For example, the input pressure may be greater than <NUM> bar and less than or equal to <NUM> bar, and the output pressure may be <NUM> bar. The output pressure may be determined by the height of the melt such as molten steel. A constant amount of gas may be stably supplied to the injection unit <NUM> by the pressure regulator <NUM>.

Meanwhile, when the pressure is adjusted by the pressure regulator <NUM>, the flow rate of gas is rapidly changed. In addition, it is difficult to control the supply flow rate of gas when gas is supplied to the injection unit <NUM> while maintaining the adjusted supply pressure of gas. The flow regulator <NUM> is mounted downstream the pressure regulator <NUM> to adjust the flow rate of gas under the adjusted pressure to a desired supply flow rate. That is, the flow regulator <NUM> may adjust the supply flow rate of gas supplied to the injection unit <NUM>. In this manner, even when the internal pressure of gas in the storage unit <NUM> is reduced, the flow rate of gas supplied to the injection unit <NUM> may be stably maintained.

The flow regulator <NUM> may receive the pressure-adjusted gas passing through the pressure regulator <NUM>, adjust its flow rate to a desired supply flow rate, and output it to the inside of the pipe <NUM>. Thus, gas may be supplied to the injection unit <NUM> at a constant supply pressure and flow rate.

Even if the pressure-adjusted gas passing through the pressure regulator <NUM> is supplied to the flow regulator <NUM> at an irregular flow rate as the internal pressure of the pressure container <NUM> is lowered, the flow rate may be adjusted at a desired supply flow rate, for example of about <NUM>/min by passing through the flow regulator <NUM>. Thus, gas may be supplied from the flow regulator <NUM> to the injection unit <NUM> at the flow rate of <NUM>/min under the pressure of <NUM> bar. The flow regulator <NUM> may include various types of flow meters capable of automatically adjusting a flow rate while constantly maintaining the gas pressure as an isostatic pressure.

The pressure regulator <NUM> and flow regulator <NUM> may be controlled by a control unit (not shown). They may be mechanically operated under the control of the control unit to sequentially adjust the supply pressure and flow rate of gas. In addition, the pressure regulator <NUM> and flow regulator <NUM> may adjust the magnitude of preset supply pressure and flow rate under the control of the control unit. That is, if it is desired to reduce the supply pressure as needed, the control unit may control the pressure regulator <NUM> to reduce the outlet pressure of the pressure regulator <NUM>. If it is desired to reduce the supply flow rate as needed, the control unit may control the flow regulator <NUM> to reduce the outlet flow rate of the flow regulator <NUM>.

For example, when the height of the melt M is lowered, the pressure of the melt M, for example iron static pressure is lowered, so a pressure applied to the injection unit <NUM> by the melt M is also reduced, resulting in reducing the supply pressure. When the temperature of the melt M is changed, the properties such as fluidity and viscosity of the melt M are also changed, and the supply flow rate may be correspondingly changed.

The supply unit <NUM> may not be connected to the utility lines used in the steelmaking and continuous casting processes. That is, during the entire process using the container unit <NUM>, it is sufficient if only the gas filled in the storage unit <NUM> is supplied to the injection unit <NUM> to prevent clogging of the injection unit <NUM>.

<FIG> is a front view of the apparatus for processing a melt according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the apparatus for processing a melt according to an embodiment of the present invention further includes a weight adjustment unit <NUM>. The weight adjustment unit <NUM> may be mounted on an outer surface of the container unit <NUM> at a position opposite to the storage unit <NUM> in a front-rear direction with the container unit <NUM> interposed therebetween. The weight adjustment unit <NUM> may prevent the eccentricity of the center of gravity of the container unit <NUM> by the storage unit <NUM>. The weight adjustment unit <NUM> may extend in a vertical direction, and may include a holding bar <NUM> supported by the protrusion member <NUM> and a weight <NUM>. The weight <NUM> may be formed to be curved along a shape of an outer circumferential surface of the container body <NUM>, be seated on an upper surface of the protrusion member <NUM>, and be fitted to the holding bar <NUM>. The weight adjustment unit <NUM> may be located in front of the container body <NUM>. The weight adjustment unit <NUM> may adjust the number of weights <NUM> to position the center of gravity of the container body <NUM> between a pair of locking members <NUM>. Thus, even if the storage unit <NUM> is large and a large amount of gas is filled in the storage unit <NUM>, the center of gravity of the container unit <NUM> may not be biased toward the storage unit <NUM>.

A plurality of holding bars <NUM> may be provided. The plurality of holding bars <NUM> may be spaced apart from each other in at least one direction of a left-right and vertical directions. Each of upper and lower ends of the holding bar may be fitted respectively to surfaces facing each other of the protrusion member <NUM> arranged in the vertical direction.

The weight <NUM> may be a member of a bow shape and may have an area that may be seated on the upper surface of the protrusion member <NUM>. A plurality of weights <NUM> may be stacked on the top of each other. In this case, irregularities and adhesive members may be provided on upper and lower surfaces of the weight <NUM>. Thus, when the plurality of weights <NUM> are stacked on the top of each other, they may be coupled to each other to prevent movement. The weight <NUM> may have a fitting groove (h) formed on its side. The holding bar <NUM> may be fitted into the fitting groove (h). The fitting groove (h) may be formed on a front side of the weight <NUM>. Thereby, the weight <NUM> may be stably protected between the container body <NUM> and the holding bar <NUM>. Here, term front side refers to a side toward the front of the container body <NUM>. The rear side may be a side facing the container body <NUM>.

According to the foregoing embodiment of the present invention, even if the pressure of gas filled in the pressure container <NUM>, for example the internal pressure of the pressure container <NUM> is varied, the gas may be stably supplied to the injection unit <NUM> at constant supply pressure and flow rate over a long time. In addition, the exposure of the pressure container <NUM> to radiant heat from the melt M can be minimized. As a result, it is possible to suppress or prevent the penetration of the melt M into the injection unit <NUM> over a long time.

<FIG> and <FIG> are conceptual views showing a supply unit according to a first modified embodiment of the present invention. Specifically, <FIG> is a conceptual diagram illustrating a connection structure of a supply unit according to the first modified embodiment of the present invention when a plurality of storage units, for example two storage units are used, and <FIG> is a conceptual diagram showing a connection structure of a supply unit according to the first modified embodiment of the present invention when a single storage unit is used.

Referring to <FIG>, according to the first modified embodiment of the present invention, the supply unit <NUM> may include a first blocking valve <NUM> mounted on the pipe <NUM> between the safety valve <NUM> and the pressure regulator <NUM>, a discharge valve <NUM> mounted on the pipe <NUM> between the first blocking valve <NUM> and the safety valve <NUM>, and a second blocking valve <NUM> mounted on the pipe <NUM> between the pressure regulator <NUM> and the flow regulator <NUM>.

The first blocking valve <NUM> may include a manual needle valve. The first blocking valve <NUM> may manually block a gas supply from the storage unit <NUM> to the supply unit <NUM> when the container unit <NUM> is not operated. The discharge valve <NUM> may include a manual ball valve. When the container unit <NUM> starts to operate again, the discharge valve <NUM> may discharge high-pressure gas accumulated in the pipe <NUM> between the first blocking valve <NUM> and the storage unit <NUM> to reduce pressure between the first blocking valve <NUM> and the storage unit <NUM>. Thereby, the pressure regulator <NUM> may be protected from damage when the container unit <NUM> is operated again. The discharge valve <NUM> may discharge high pressure gas to a ventilation line L. The second blocking valve <NUM> may include a manual needle valve, and may be used to block a gas flow between the pressure regulator <NUM> and the flow regulator <NUM> as needed.

The supply unit <NUM> may further include a pressure gauge <NUM> mounted on the pipe <NUM> downstream the flow regulator <NUM> and a switching valve <NUM> mounted on the pipe <NUM> between the pressure gauge <NUM> and the injection unit <NUM>.

The pressure gauge <NUM> may measure the pressure of gas output from the flow regulator <NUM>. The measurement result from the pressure gauge <NUM> is transmitted to the control unit. When an actual pressure measured by the pressure gauge <NUM> is different from an output pressure set in the pressure regulator <NUM>, the control unit may promptly notify a user of such situation.

The switching valve <NUM> may be a three-way valve, for example. The switching valve <NUM> may be selectively detached from the utility line U. When the switching valve <NUM> is mounted on the utility line U, the switching valve <NUM> may block a gas flow from the flow regulator <NUM> to the injection unit <NUM> and open a gas flow from the utility line U to the injection unit <NUM>. When the switching valve <NUM> is disconnected from the utility line U, the switching valve <NUM> may open the gas flow from the flow regulator <NUM> to the injection unit <NUM>.

<FIG> is a schematic diagram showing a weight adjustment unit according to a second modified embodiment of the present invention.

Referring to <FIG> and <FIG>, according to the second modified embodiment of the present invention, the weight adjusting unit <NUM> is installed to be at least partially movable in a horizontal direction along an outer surface of the container unit such that the center of gravity of the container unit <NUM> may be adjusted depending on a change in weight by the consumption of gas in the storage unit <NUM>. To this end, the weight adjustment unit <NUM> includes a holding bar <NUM>, a weight <NUM>, an actuator <NUM>, and a guide rail <NUM>.

The holding bar <NUM> may extend in a vertical direction in front of the container body <NUM>. A plurality of holding bars <NUM> may be provided to be spaced apart from each other in a left-right direction, and may be disposed between the protrusion members <NUM>. Also, a plurality of weights <NUM> may be provided. The plurality of weights <NUM> may be arranged in the left-right direction, and may be stacked on the top of each other. A left group of weights <NUM> and a right group of weights <NUM> may be fitted into different holding bars <NUM>.

The actuator <NUM> may be adjusted in length in the left-right direction, be supported on an outer surface of the container body <NUM>, and be connected to the holding bar <NUM> on a one-to-one basis. The guide rail <NUM> may be respectively formed on surfaces facing each other in the protrusion members <NUM> arranged in a vertical direction and extend in a circumferential direction of the container body <NUM> along the protrusion members <NUM>. Each of upper and lower ends of the holding bar <NUM> may be mounted on the guide rail <NUM>.

The actuator <NUM> is controlled by the control unit. The actuator <NUM> may move the holding bars <NUM> toward the front of the container body <NUM> so that they get closer to each other when an amount of gas filled in the storage unit <NUM> is relatively large. To the contrary, when the gas amount is relatively small, the actuator <NUM> may pull the holding bars <NUM> toward the locking members <NUM> so that they move away from each other in a left-right direction. A position of the weight <NUM> is adjusted in a front-rear direction depending on the movement of the holding bars <NUM>, thereby adjusting the center of gravity.

Hereinafter, a method for processing a melt according to an embodiment of the present invention will be described in detail with reference to <FIG>.

According to an embodiment of the present invention, a method for processing a melt includes the steps of providing a container unit <NUM> that is movable together with a storage unit <NUM> filled with gas; conveying the container unit <NUM> containing the melt M from a first position to a second position; supplying gas to an injection unit <NUM> mounted on a lower portion of the container unit <NUM> to inject the gas into the melt M in the container unit <NUM>; adjusting the supply pressure of gas supplied to the injection unit <NUM>; and adjusting the supply flow rate of gas under the adjusted supply pressure.

First, the storage unit <NUM> filled with gas and the container unit <NUM> which are movable together are provided. The storage unit <NUM> may be in a state that gas is filled under the pressure of about <NUM> to <NUM> bar. However, a filling pressure may have any pressure range which is higher or lower than the above-mentioned pressure. At this time, the container unit <NUM> may contain the melt M. The melt M may be at least one of molten steel and slag.

Then, the container unit <NUM> containing the melt M is conveyed from the first position to the second position. The first position may be a place where the container unit <NUM> is currently located, and the second position may be a predetermined place where the container unit <NUM> is to be moved. For example, when the container unit <NUM> transports molten steel for which converter steel taping has been completed to a subsequent process, a place where a converter process facility is located may be the first position, and a place where a subsequent process facility for subsequent processes such as a bubbling, secondary refining, or continuous casting process is located may be the second position.

During the foregoing processes, gas is supplied to the injection unit <NUM> such that the gas may be injected into the melt M in the container unit <NUM>. Specifically, gas filled in the storage unit <NUM> may be supplied to the injection unit <NUM> using the supply unit <NUM>. At this time, when an amount of gas filled in the storage unit <NUM> is reduced, the flow rate and pressure of gas supplied to the injection unit <NUM> may be irregularly varied. As a result, a molten metal surface of the melt M becomes unstable, so that the quality may be deteriorated. To prevent such situation, during said process, the supply pressure of gas supplied to the injection unit <NUM> is adjusted and subsequently the supply flow rate of gas under the adjusted pressure is also adjusted.

In this context, the reason for first adjusting the gas supply pressure is as follows; after adjusting the pressure of gas, typically the flow rate of gas is significantly fluctuated. So, to supply gas to the injection unit <NUM> at a stable flow rate, the pressure of gas is first adjusted by the pressure regulator <NUM> and then the flow rate of gas is adjusted by the flow regulator <NUM> and the gas is supplied to the injection unit <NUM>.

The step of adjusting the pressure may include reducing the supply pressure to a reference pressure that is lower than the filling pressure of the storage unit <NUM> and higher than the pressure of the melt M. Alternatively, the step of adjusting the pressure may include reducing the supply pressure to a reference pressure that is lower than the internal pressure of the utility line in at least one of the first position and the second position and higher than the pressure of the melt M. The pressure of the melt may be a pressure at the bottom of the melt, that is, a pressure applied to an upper surface of the bottom plate of the container unit <NUM> by the melt.

At this time, the pressure of the melt M may be a pressure which is applied to the injection unit <NUM> by the melt M, for example an iron static pressure. The reference pressure may be a desired pressure at which the gas may be injected into the melt M via the injection unit <NUM> while preventing the melt M from entering the injection unit <NUM>. Alternatively, the reference pressure may be a desired pressure which prevents naked molten metal surface from being formed on a molten metal surface of molten steel when the melt M contains molten steel and slag.

As such, since gas is supplied to the injection unit <NUM> under the supply pressure reduced to the reference pressure, a small amount of gas may be used. Also, it is possible to prevent the melt M from entering the injection unit <NUM> and to prevent naked molten metal from being formed on a molten metal surface of the melt M. The reference pressure may be about <NUM> bar. For example, the reference pressure may be <NUM> times lower than the supply pressure of the utility line as described above.

Meanwhile, as a height of the melt m increases, the pressure of the melt M, for example an iron static pressure is also increased, so the supply pressure must be correspondingly increased. For example, when the density of the melt is <NUM>/m3, if a height of the melt m increases by about <NUM>, the supply pressure must be increased by about <NUM> bar. Thereby, even if a height of the melt m is altered, it is possible to supply gas under an appropriate pressure to the injection unit <NUM>. As such, the reference pressure may be determined depending on a height of the melt M in the container unit <NUM>.

Then, the supply flow rate of the pressure-adjusted gas is adjusted. Specifically, the supply flow rate may be increased or decreased to follow a preset reference flow rate while maintaining a constant level of the supply pressure. Thereby, even if the flow rate of gas is irregularly varied in the pressure regulator <NUM>, the gas may be supplied to the injection unit <NUM> at a constant supply flow rate by adjusting the flow rate by the flow regulator <NUM>. The reference flow rate may be a flow rate which may not cause naked molten metal on a molten metal surface of the melt M or a flow rate which may prevent a rapid stirring of the melt M. However, the reference flow rate may be defined in various ways.

When the foregoing processes are performed, it is possible to prevent a high temperature from being transferred from the container unit <NUM> to the pressure container <NUM> of the storage unit <NUM> by using the protective container <NUM> and the anti-shattering plate <NUM>. It is also possible to prevent shattering matters generated from the melt M from contaminating the pressure container <NUM>.

Also, when the foregoing processes are performed, if the internal pressure of the storage unit <NUM> is rapidly increased exceeding a specific pressure due to a temperature increase in the storage unit <NUM>, the supply pressure of gas led from the pressure container <NUM> to the pressure regulator <NUM> is rapidly increased. In this case, a part of the pipe <NUM> through which gas flows, for example sub-pipes 410a may be opened using the safety valve <NUM> of the supply unit <NUM> to reduce the pressure of gas supplied to pressure regulator <NUM>. Thereby, it is possible to prevent damage to the pressure regulator <NUM> and to prevent fluctuations in the supply pressure. Here, said specific pressure may be any pressure in a pressure range that is higher than the filling pressure of the storage unit <NUM> and lower than an acceptable pressure which is an internal pressure endured by the pressure container <NUM> of the storage unit <NUM>.

While supplying gas to the injection unit <NUM> under the adjusted supply pressure and flow rate, the steps of preventing a temperature from being transferred to the pressure container <NUM>, preventing the pressure container <NUM> from being contaminated and preventing the supply pressure from being fluctuated may be optionally performed. For example, when gas is supplied to the injection unit <NUM> with the supply pressure and flow rate adjusted, at least one of these steps may be performed.

In addition, when the foregoing processes are performed, it is possible to prevent the center of gravity of the container unit <NUM> from being biased by applying a weight to the container unit <NUM> using the weight adjustment unit <NUM> from a side opposite to the storage unit <NUM> about the container unit <NUM>. In this manner, depending on an amount of gas consumed in the storage unit <NUM>, an action point to which a weight is applied by the weight adjustment unit <NUM> is moved toward the storage unit <NUM> to stably maintain the center of gravity.

As such, even if the internal pressure of the pressure container <NUM> of the storage unit <NUM> is altered, since gas is supplied to the injection unit <NUM> under a constant flow rate and pressure over a long time, it is possible to prevent the melt M from penetrating into the injection unit <NUM> and to prevent the injection unit from being damaged.

Claim 1:
An apparatus for processing a melt including:
a container unit (<NUM>) having an inner space to receive a melt;
an injection unit (<NUM>) mounted on a lower portion of the container unit (<NUM>) to inject gas into the melt in the container unit (<NUM>);
a storage unit (<NUM>) mounted on the container unit (<NUM>) and filled with gas;
a supply unit (<NUM>) installed in the container unit (<NUM>) to connect the injection unit (<NUM>) and the storage unit (<NUM>) and having a pressure regulator (<NUM>) for regulating a supply pressure of the gas and a flow regulator (<NUM>) for regulating a supply flow rate of the gas under the adjusted supply pressure; and
a weight adjustment unit mounted on an outer surface of the container unit (<NUM>) at a position opposite to the storage unit (<NUM>) in a horizontal direction with the container unit (<NUM>) interposed therebetween,
wherein the weight adjustment unit is installed to be at least partially movable in a horizontal direction along an outer surface of the container unit (<NUM>) to adjust the center of gravity,
the weight adjustment unit (<NUM>) includes:
a holding bar (<NUM>);
a weight (<NUM>);
an actuator (<NUM>) controlled by a control unit and configured to move the holding bar (<NUM>) depending on an amount of gas filled in the storage unit (<NUM>);
a guide rail (<NUM>); and
wherein the position of the weight (<NUM>) is adjusted in a front-rear direction depending on the movement of the holding bar (<NUM>).