Nitrogen gas blower

Abstract

The present invention provides a nitrogen gas blowing device that efficiently blows nitrogen gas into the interior of refrigerant pipes when joining them by brazing, welding, or other joining methods. [Solution] The device comprises a main body 2 for supplying and stopping nitrogen gas into the first refrigerant pipe 51 or the second refrigerant pipe 53; a main body side operating means 21, one end of which is electrically connected to the operating circuit of the main body 2 and the other end of which is electrically connected to the building structure 40, the first refrigerant pipe 51, and the second refrigerant pipe 53; and a welding side hand operating means 22, which is electrically connected to the building structure 40 and the other end of which can be electrically connected to the first refrigerant pipe 51 or the second refrigerant pipe 53 at the welded joint of the first refrigerant pipe 51 and the second refrigerant pipe 53.

Description

Technical Field

[0001] The present invention relates to a nitrogen gas blowing device used for refrigerant pipe construction of buildings, and particularly to a nitrogen gas blowing device capable of performing opening and closing operations of a nitrogen gas cylinder at the joint of the refrigerant pipe.

Background Art

[0002] When installing air conditioning equipment in multi-story buildings such as steel frame structures, reinforced concrete structures, and steel frame reinforced concrete structures, construction work for installing an outdoor unit on the rooftop part of the building body, etc., construction work for installing an indoor unit on the ceiling part of each floor of the building body, etc., and refrigerant pipe construction for installing refrigerant pipes connecting between the outdoor unit and the indoor unit on the ceiling part of the building body of each floor are carried out.

[0003] In refrigerant pipe construction, for example, a plurality of support fittings are attached at predetermined intervals to the ceiling part of the building body, and two refrigerant pipes are supported by these support fittings so as to span the entire width of the ceiling part. One end of both refrigerant pipes is connected to the outdoor unit side, and the other end is connected to the indoor unit side.

[0004] As the refrigerant pipe, for example, standard copper pipes such as general copper pipes (JIS H3300 phosphorus-deoxidized copper seamless pipes) and coated copper pipes for refrigerants (Japan Copper Center standard JCDA0009) are used.

[0005] To install this type of copper pipe on the ceiling part of the building body and make it function as a refrigerant pipe, for example, two copper pipes with different diameters are prepared, the thinner copper pipe is used as the high-pressure side pipe, and the thicker copper pipe is used as the low-pressure side pipe, and they are supported by a plurality of support fittings so as to span the entire width of the ceiling part of the building body.

[0006] In this case, in order to match the dimensions of the installation location of the copper pipe, it is necessary to perform an operation of joining the ends of a plurality of copper pipes together by brazing, welding or other joining means to form a predetermined dimension.

[0007] To join the ends of copper pipes by brazing, one end of one copper pipe is enlarged using a special tool, the other end of the copper pipe is inserted into the enlarged end of the first copper pipe, and the outer surface between the ends of both copper pipes is preheated by heating it circumferentially with a torch. Then, the brazing material is melted and poured into the joint between the ends of the two copper pipes, joining the ends of the two copper pipes via the brazing material.

[0008] In this process, nitrogen gas is continuously flowed from one end of one copper pipe to the other end of the other copper pipe, replacing the air inside both copper pipes during the joining process (nitrogen gas blowing). This prevents the formation of an oxide film on the inner surface of the joint between the two adjacent copper pipes.

[0009] An invention relating to a method for joining copper pipes of this type is described in Patent Document 1. In the joining method described in Patent Document 1, when two copper pipes are joined to each other by brazing, an enlarged diameter section is provided at the end of one copper pipe, an opening that penetrates from the inside to the outside is provided at the end of the other copper pipe to be inserted into the enlarged diameter section, the end of the other copper pipe is inserted into the enlarged diameter section of the end of the first copper pipe to a position where the opening is not blocked, and a nitrogen gas cylinder is opened to fill the inside of the joint between the two copper pipes with nitrogen gas to create a non-oxidizing atmosphere.

[0010] Next, the end of the other copper pipe is inserted into the widened end of the first copper pipe as far as it will go to close the opening. With the valves of the oxygen cylinder and acetylene cylinder opened, oxygen gas and acetylene gas are ejected from the nozzles and burned, preheating the joint between the two copper pipes in a circumferential direction, and melting the brazing material and pouring it into the joint between the two copper pipes. This allows the ends of the two copper pipes to be joined via the brazing material.

[0011] Patent Document 2 describes an invention relating to an inert gas supply device for welding work. The device described in Patent Document 2 comprises a master unit of the inert gas supply device and a slave unit (corresponding to the manual control line of the present invention) that transmits to the master unit through the metal pipe to be welded.

[0012] In this configuration, a cylinder is connected to the connection port of the master unit via a pressure-resistant hose, the gas outlet is connected to one end of the metal pipe to be welded via a gas blow hose, the receiving terminal of the master unit is connected to the metal pipe to be welded, and the transmitting terminal of the slave unit is connected to the metal pipe to be welded.

[0013] Then, when the blow-start switch on the sub-unit is turned on, the sub-unit's circuit emits an open signal for the electromagnetic valve, and this signal is sent to the main unit's circuit through the metal pipe, causing the electromagnetic valve to open and inert gas to be supplied from the cylinder into the metal pipe.

[0014] Furthermore, by performing welding work on the joints of the metal pipes in this state, it is possible to prevent the formation of an oxide film on the inner surface of the metal pipes.

[0015] Furthermore, when welding is complete, turning on the blow-stop switch causes the slave unit's circuit to emit a closing signal for the electromagnetic valve. This signal is sent through the metal pipe to the master unit's circuit, closing the electromagnetic valve and stopping the supply of inert gas into the metal pipe. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] Japanese Patent Publication No. 2020-139629 [Patent Document 2] Japanese Patent Application Publication No. 5-337649 [Overview of the project] [Problems that the invention aims to solve]

[0017] By the way, in the joining method described in Patent Document 1, when there are multiple joints in the copper pipe, the worker has to return to the location where the nitrogen gas cylinder is installed each time the joint changes, and open, close, or adjust the flow rate of the nitrogen gas cylinder valve. Therefore, if the nitrogen gas cylinder is installed at a distance, opening and closing the valve of the nitrogen gas cylinder becomes very time-consuming and the work efficiency is poor.

[0018] Furthermore, the apparatus described in Patent Document 2 allows the opening and closing of the inert gas cylinder to be performed remotely using a master unit and a slave unit. Therefore, the worker does not need to return to the location where the cylinder is installed each time the welding site changes, and the work efficiency problems described in Patent Document 1 do not occur.

[0019] However, since the main unit is connected to the metal pipe to be welded via a gas blow hose, the main unit's receiving terminal is connected to the metal pipe to be welded, and the sub-unit's transmitting terminal is connected to the metal pipe to be welded, and the sub-unit is operated to open and close the electromagnetic valve, supplying and stopping the supply of inert gas from the gas cylinder via the gas blow hose, if there are multiple metal pipe systems, the gas blow hose, receiving terminal and transmitting terminal must be set up on each metal pipe system, which reduces work efficiency.

[0020] This invention has been made in view of the above-mentioned conventional problems, and aims to provide a nitrogen gas blowing device that can supply nitrogen gas from a nitrogen gas cylinder to the joint of a copper pipe during refrigerant piping work for air conditioning equipment, thereby enabling efficient copper pipe joining work. [Means for solving the problem]

[0021] To solve the above-mentioned problems, this invention employs the following means. In other words, the first invention is a nitrogen gas blow device that supplies nitrogen gas into the interior of a first refrigerant pipe or a second refrigerant pipe when extending the refrigerant pipe by joining means such as brazing or welding during construction work to install refrigerant pipes in the ceiling portion of the structural frame of a steel frame, reinforced concrete, or steel-reinforced concrete building, and is characterized by comprising: a device body for supplying and stopping the supply of nitrogen gas into the interior of the first refrigerant pipe or the second refrigerant pipe; a device body-side operating means having one end electrically connected to the operating circuit of the device body and the other end electrically connected to the structural frame, the first refrigerant pipe, and the second refrigerant pipe; and a welding-side hand operating means at the welding point of the first refrigerant pipe and the second refrigerant pipe, having one end of a hand operating wire electrically connected to the structural frame and the other end electrically connectable to the first refrigerant pipe or the second refrigerant pipe.

[0022] According to the nitrogen gas blowing device of the present invention, by electrically connecting the hand-operated wire of the welding-side hand-operated means to the building body and electrically connecting or disconnecting one end to the first refrigerant piping or the second refrigerant piping, nitrogen gas can be supplied to or stopped from the first refrigerant piping or the second refrigerant piping via the operation circuit of the device body. In this case, since the connection or disconnection of the welding-side hand-operated means to the first refrigerant piping or the second refrigerant piping only needs to be performed at the welding points of the first refrigerant piping and the second refrigerant piping, when there are multiple joints between the first and second refrigerant piping, the operator does not need to return to the position of the device body to supply or stop the nitrogen gas after each joint operation, thus enabling efficient nitrogen gas blowing operations.

[0023] The second invention is a nitrogen gas blow device as described in the first invention, wherein the device body comprises a first solenoid valve for supplying and stopping nitrogen gas to the first refrigerant piping, a second solenoid valve for supplying and stopping nitrogen gas to the second refrigerant piping, and an operating circuit for opening and closing the first and second solenoid valves, and the operating means on the device body side and the welding side handheld operating means are provided between the operating circuit and the frame, the first refrigerant piping, and the second refrigerant piping.

[0024] According to the nitrogen gas blowing device of the present invention, by electrically connecting one end of the welding-side hand operation means to the housing and the other end to the first refrigerant pipe or the second refrigerant pipe, or by disconnecting the connection, the opening and closing operations of the first solenoid valve and the second solenoid valve are performed via the operation circuit of the device main body, and nitrogen gas is supplied to or the supply of nitrogen gas is stopped to the first refrigerant pipe or the second refrigerant pipe via the first solenoid valve and the second solenoid valve.

[0025] Therefore, when there are a plurality of joint locations of the first refrigerant pipe and the second refrigerant pipe, each time the start and end of the joint operation at one location are performed, it is not necessary for the operator to return to the position of the device main body to perform the operations of supplying and stopping nitrogen gas, so the nitrogen gas blowing operation can be performed efficiently.

[0026] Also, when starting the joint operation of the second refrigerant pipe after the joint operation of the first refrigerant pipe is completed, the operator only needs to remove the welding-side hand operation means from the first refrigerant pipe, reconnect it to the second refrigerant pipe, and switch from the first solenoid valve to the second solenoid valve, so the time and labor required for the setup of operation switching can be significantly reduced, and the operation efficiency can be significantly improved.

[0027] Moreover, the third invention is the nitrogen gas blowing device described in the second invention, wherein the device main body side operation means includes a first operation wire having one end electrically connected to the plus side of the operation circuit and the other end electrically connected to the first refrigerant pipe, a second operation wire having one end electrically connected to the plus side of the operation circuit and the other end electrically connected to the second refrigerant pipe, and a third operation wire having one end electrically connected to the minus side of the operation circuit and the other end electrically connected to the housing, and the welding-side hand operation means includes a hand operation wire having one end electrically connected to the housing and the other end electrically connectable to the first refrigerant pipe or the second refrigerant pipe.

[0028] According to the nitrogen gas blowing device of the present invention, by connecting one end of the hand-operated wire of the welding-side hand-operated means to the building structure and connecting the other end to the first refrigerant piping or the second refrigerant piping, or disconnecting the connection, the connection between the positive and negative sides of the operating circuit of the main body of the device can be closed or opened, thereby controlling the opening and closing operations of the first solenoid valve and the second solenoid valve. As a result, the opening and closing of the solenoid valve can be performed at the welding site, and nitrogen gas blowing work can be performed efficiently.

[0029] Furthermore, the fourth invention is characterized in that, in the nitrogen gas blowing device of the third invention, clips are provided at both ends of the first operating wire, the second operating wire, and the third operating wire, and clips are provided at both ends of the hand-operated operating wire.

[0030] According to the nitrogen gas blow device of the present invention, the first control line, second control line, third control line, and hand control line can be easily connected to the main body, the first refrigerant piping, and the second refrigerant piping via clips.

[0031] Furthermore, the fifth invention is a nitrogen gas blower described in any one of the first to fourth inventions, characterized in that a DC 6V voltage is applied to the operating circuit of the main body of the device.

[0032] According to the nitrogen gas blowing device of this invention, since DC 6V is used as the operating power supply, the risk of electric shock to workers at the site where refrigerant piping is joined can be made extremely low, and the safety of the workers can be ensured.

[0033] Furthermore, the sixth invention is a nitrogen gas blowing device according to the second invention, characterized in that the operating circuit of the device body incorporates a circuit that allows setting the operating time of the first solenoid valve and the second solenoid valve, and selecting between manual and automatic operation.

[0034] According to the nitrogen gas blowing device of this invention, it is possible to set the operating time and switch between automatic and manual operation, so that nitrogen gas is not used more than necessary, and joining work can be performed with the minimum amount of nitrogen gas required, thereby eliminating waste of nitrogen gas. [Effects of the Invention]

[0035] As described above, with the nitrogen gas blow device of the invention, by electrically connecting one end of the welding-side hand-operated means to the building body and electrically connecting or disconnecting the other end to the first refrigerant piping or the second refrigerant piping, nitrogen gas can be supplied to or stopped from the first refrigerant piping or the second refrigerant piping via the operating circuit of the device body. In this case, at the welding points of the first and second refrigerant pipes, the operator only needs to connect and disconnect the welding-side hand-operated means to the first or second refrigerant pipe. Therefore, when there are multiple joints between the first and second refrigerant pipes, the operator does not need to return to the main unit of the device to supply and stop the nitrogen gas after each joint, thus enabling efficient nitrogen gas blowing operations.

[0036] Furthermore, if the joining work for the second refrigerant piping is to begin after the joining work for the first refrigerant piping has been completed, the connection of the welding-side hand-operated means to the first refrigerant piping can be disconnected and reconnected to the second refrigerant piping. This significantly reduces the time and effort required for switching between tasks, and greatly improves work efficiency.

[0037] Furthermore, by connecting one end of the hand-operated wire of the welding-side hand-operated means to the building structure and the other end to the first refrigerant piping or the second refrigerant piping, or by disconnecting the connection, the positive and negative sides of the control circuit of the main unit of the device can be opened or closed, thereby controlling the opening and closing operations of the first and second solenoid valves. This allows the opening and closing of the solenoid valves to be performed at the welding site, enabling efficient nitrogen gas blowing operations.

[0038] Furthermore, since the first control line, second control line, third control line, and hand control line can be easily connected to the frame, first refrigerant piping, and second refrigerant piping via clips, nitrogen gas blowing operations can be performed efficiently.

[0039] Furthermore, since it uses DC 6V as the operating power supply, the risk of electric shock to workers at sites where refrigerant piping is being joined can be made extremely low, thus ensuring worker safety.

[0040] Furthermore, since the operating time can be set and the system can be switched between automatic and manual modes, operators can choose between automatic and manual operation according to their skill level. This prevents the use of more nitrogen gas than necessary, allowing the joining process to be performed with the minimum required amount of nitrogen gas, thus eliminating waste. [Brief explanation of the drawing]

[0041] The drawings illustrate specific embodiments of the present invention relating to this disclosure, including not only essential components of the invention but also optional and preferred embodiments. [Figure 1] This is an explanatory diagram showing one implementation of the nitrogen gas blowing device according to the present invention, and more particularly an explanatory diagram showing an example of its application to refrigerant piping work in a building. [Figure 2] This is an enlarged view of the joint in Figure 1. [Figure 3] This is a system diagram of the main unit of the device. [Modes for carrying out the invention]

[0042] As shown in Figure 1, the nitrogen gas blow device 1 of the present invention is applicable when installing air conditioning equipment in buildings such as steel-framed, reinforced concrete, and steel-reinforced concrete structures, and in this embodiment, it is applied when installing air conditioning equipment in a two-story steel-framed building.

[0043] When installing air conditioning equipment in a steel-framed building, for example, as shown in Figures 1 and 2, the work involves installing an outdoor unit 55 on the rooftop of the building's structure 40, installing indoor units (not shown) on the ceilings of each floor of the structure 40, and installing refrigerant piping 50 connecting the outdoor and indoor units on the ceilings of the structure 40 on each floor.

[0044] In refrigerant piping work, first, multiple support brackets 41 are placed at predetermined intervals across the entire width of the ceiling portion of the building's structure 40 (in this embodiment, the ceiling portion of the first floor), and each support bracket 41 is fixed to a metal part such as a beam in the ceiling portion of the structure 40 by welding or other means, or fixed to a deck plate with a grip anchor. Furthermore, the metal parts of the structural frame 40, such as beams and columns, are assumed to be in contact with the ground.

[0045] Next, using general copper pipes or coated copper pipes for refrigerants (general copper pipes in this embodiment), two refrigerant piping systems 50, a first refrigerant piping system 51 and a second refrigerant piping system 53, are constructed using these copper pipes 52, and both pipes 51 and 53 are supported by support brackets 41 on the ceiling portion of the building structure 40.

[0046] Furthermore, in order to extend the first refrigerant pipe 51 and the second refrigerant pipe 53 to the outdoor unit 55 on the rooftop floor, the refrigerant pipes 51 and 53 are installed vertically along the walls of the first and second floors, and these refrigerant pipes 51 and 53 are bent at the rooftop and extended along the floor surface of the rooftop floor to the location of the outdoor unit 55. These refrigerant pipes 51 and 53 are supported by support brackets 41 or the like on metal parts such as columns on the first and second floors and deck plates on the rooftop. In the case of deck plates, grip anchors are used.

[0047] In the ceiling section, multiple copper pipes 52 are sequentially joined together by joining means such as brazing or welding (brazing in this embodiment) to form a predetermined size, and the copper pipes 52 are spread across the installation locations in the ceiling section. Specifically, the first copper pipe 52a is placed on the base end side of the installation location, and the other end (joining side) of this first copper pipe 52a is expanded in diameter using a special tool.

[0048] Next, the second copper pipe 52b is positioned on the other end of the first copper pipe 52a, one end of the second copper pipe 52b is inserted inside the enlarged diameter section at the other end of the first copper pipe 52a, and the joining process begins by brazing the joint portion of both copper pipes 52a and 52b together with their axes aligned.

[0049] At this time, nitrogen gas is supplied from the nitrogen gas cylinder 45 into the interior of the first copper pipe 52a through one end opening of the first copper pipe 52a and discharged from the other end opening of the second copper pipe 52b, filling the inner surface of both copper pipes 52a and 52b, including the joint portion, with nitrogen gas. This replaces the air inside both copper pipes 52a and 52b with nitrogen gas, performing a blow operation to prevent the formation of an oxide film on the inner surface of the joint portion.

[0050] Then, in this state, oxygen gas and acetylene gas are supplied to the torch and burned to preheat the outer circumference of the joint between the two copper pipes 52a and 52b in the circumferential direction, melt the brazing material and pour it into the joint. Then, by cooling the joint by appropriate means, the ends of the two copper pipes 52a and 52b are joined. By performing this operation continuously on multiple copper pipes 52, a first refrigerant piping 51 and a second refrigerant piping 53 consisting of multiple refrigerant copper pipes 50 of a predetermined length can be constructed in the ceiling portion of the building structure 40.

[0051] Although a detailed explanation will be omitted, by performing the same work on the walls of the first floor, the walls of the second floor, and the floor surface of the rooftop, the first refrigerant piping 51 and the second refrigerant piping 53 can also be constructed in those areas.

[0052] The nitrogen gas blow device 1 of this embodiment is applied to the brazing joint work of the copper pipe 52 as described above. As shown in Figures 1 to 3, the nitrogen gas blow device 1 of this embodiment comprises a device body 2 that controls the supply of nitrogen gas from a nitrogen gas cylinder 45 to the inside of the refrigerant piping 50 (first refrigerant piping 51 and second refrigerant piping 53), and a device body-side operating means 21 and a welding-side hand-operated means 22 for operating the device body 2.

[0053] As shown in Figure 3, the main body of the device 2 includes a box-shaped operation box 3 with an openable and closable lid. This operation box 3 is equipped with components such as power supply from a circuit breaker 19 to which AC100V is input on the primary side, solenoid valves 5 and 8 that open and close when the power supply is stopped, and an operation circuit 23 that controls the opening and closing operations of the solenoid valves 5 and 8.

[0054] The control circuit 23 consists of components such as a timer that controls the operating time of the solenoid valves 5 and 8, a relay, and a changeover switch that switches between manual and automatic operation of the solenoid valves 5 and 8.

[0055] The solenoid valves 5 and 8 comprise a first solenoid valve 5 that supplies and stops nitrogen gas to the first refrigerant pipe 51 of the refrigerant piping 50, and a second solenoid valve 8 that supplies and stops nitrogen gas to the second refrigerant pipe 53. In this embodiment, two-port solenoid valves are used for the first solenoid valve 5 and the second solenoid valve 8, and they are installed in parallel inside the control box 3. Furthermore, instead of using two-port solenoid valves 5 and 8, three-port solenoid valves may be used.

[0056] The side of the control box 3 is provided with a nitrogen gas inlet 11 that penetrates both the inside and outside, a first nitrogen gas outlet 12 that penetrates both the inside and outside, a second nitrogen gas outlet 13 that penetrates both the inside and outside, an AC power socket that penetrates both the inside and outside, and a DC power socket that penetrates both the inside and outside.

[0057] The AC power socket is connected to the commercial power supply (AC100V) via a cable and is also connected to the primary side of the circuit breaker 19 in the control box 3. The DC power socket is connected to the device body side control means 21, which will be described later.

[0058] As shown in Figure 3, a nitrogen gas cylinder 45 is connected to the nitrogen gas inlet 11 via a first pressure-resistant hose 15 from the outside of the operation box 3. In this case, a one-touch joint plug is attached to the nitrogen gas inlet 11, and the first pressure-resistant hose 15 can be detachably attached to the nitrogen gas inlet 11 by fitting the one-touch joint socket attached to the end of the first pressure-resistant hose 15 into this plug.

[0059] One end of the second pressure-resistant hose 16 is connected to the first nitrogen gas outlet 12 from the outside of the control box 3, and the other end of the second pressure-resistant hose 16 is extended into the first refrigerant pipe 51 of the refrigerant pipe 50. In this case, a one-touch joint socket is attached to the first nitrogen gas outlet 12, and the second pressure-resistant hose 16 can be detachably attached to the first nitrogen gas outlet 12 by fitting the one-touch joint plug attached to one end of the second pressure-resistant hose 16 into this socket. The first nitrogen gas outlet 12 is connected to the outlet 7 of the first solenoid valve 5 inside the control box 3.

[0060] One end of the third pressure-resistant hose 17 is connected to the second nitrogen gas outlet 13 from the outside of the control box 3, and the other end of the third pressure-resistant hose 17 is extended into the interior of the second refrigerant piping 53. In this case, a one-touch joint socket is attached to the second nitrogen gas outlet 13, and the third pressure-resistant hose 17 can be detachably attached to the second nitrogen gas outlet 13 by fitting the plug attached to one end of the third pressure-resistant hose 17 into this socket. The second nitrogen gas outlet 13 is connected to the outlet 10 of the second solenoid valve 8 inside the control box 3.

[0061] Furthermore, the first pressure-resistant hose 15, the second pressure-resistant hose 16, and the third pressure-resistant hose 17 are pressure-resistant hoses designed for nitrogen gas.

[0062] As shown in Figure 3, a bifurcated branch pipe 14 is provided between the inlet 6 of the first solenoid valve 5 and the inlet 9 of the second solenoid valve 8 inside the control box 3 and the nitrogen gas inlet 11, which divides the flow path into two systems. The base end 14a of this branch pipe 14 is connected to the nitrogen gas inlet 11, one branch end 14b is connected to the inlet 6 of the first solenoid valve 5, and the other branch end 14c is connected to the inlet 9 of the second solenoid valve 8.

[0063] The first solenoid valve 5 and the second solenoid valve 8 are of the AC100V type, and the opening or closing operation of the first solenoid valve 5 and the second solenoid valve 8 is performed when power is supplied to or stopped from the breaker 19 side.

[0064] The control circuit 23 is configured to receive a DC 6V voltage, which controls the operation of the first solenoid valve 5 and the second solenoid valve 8.

[0065] The control of the operation of the first solenoid valve 5 and the second solenoid valve 8 includes controlling the ON / OFF state of both solenoid valves 5 and 8, controlling the operating time of both solenoid valves 5 and 8 (controlling the nitrogen gas blowing time), and controlling the manual and automatic switching of both solenoid valves 5 and 8 (controlling manual and automatic blowing of nitrogen gas).

[0066] As shown in Figure 1, the device body operating means 21 consists of three cables: a first operating line 25, a second operating line 26, and a third operating line 27, with one end of each operating line 25, 26, and 27 connected to a DC power socket via a plug. The first control line 25 and the second control line 26 are connected to the positive side of the control circuit 23, and the third control line 27 is connected to the negative side of the control circuit 23.

[0067] The other ends of the first control wire 25 and the second control wire 26 are connected to the first refrigerant pipe 51 or the second refrigerant pipe 53 of the refrigerant piping 50, respectively, and the other end of the third control wire 27 is connected to the support bracket 41 of the building structure 40. By connecting the other end of the third control wire 27 to the support bracket 41 of the building structure 40, the negative side of the control circuit 23 is grounded via the third control wire 27 and the support bracket 41.

[0068] Clips 30, 31, and 32 made of conductive material are attached to the other end of the first control wire 25, the other end of the second control wire 26, and the other end of the third control wire 27, respectively. These clips 30, 31, and 32 allow the other ends of the first control wire 25, the other end of the second control wire 26, and the other end of the third control wire 27 to be detachably attached to the first refrigerant pipe 51, the second refrigerant pipe 53, and the support bracket 41, respectively.

[0069] For the control wires 25, 26, and 27, for example, a 3-core VCTF cable (red, white, black) is used. In this embodiment, the white wire is connected to the support bracket 41 as the third control wire 27, the red wire is connected to the first refrigerant pipe 51 as the first control wire 25, and the black wire is connected to the second refrigerant pipe 53 as the second control wire 26.

[0070] As shown in Figures 1 and 2, the welding-side manual operating means 22 has a manual operating wire 33, which is made by attaching clips 34 and 35 to both ends of a single cable.

[0071] As shown in Figures 1 and 2, the clip 34 at one end of the manual control wire 33 of the welding-side manual control means 22 is connected to the support fitting 41, and the clip 35 at the other end is connected to the first refrigerant pipe 51, thereby closing the connection between the positive and negative terminals of the control circuit 23.

[0072] Furthermore, by removing clip 35 from the first refrigerant pipe 51 and connecting clip 36 to the second refrigerant pipe 53, the connection between the positive and negative terminals of the control circuit 23 is closed.

[0073] Next, the procedure for using the nitrogen gas blower 1 of this embodiment, configured as described above, will be explained with reference to Figures 1 to 3.

[0074] First, as shown in Figures 1 and 2, the first copper pipe 52a that will become the first refrigerant pipe 51 and the first copper pipe 52a that will become the second refrigerant pipe 53 are supported by support brackets 41 on the ceiling portion of the building structure 40. In this case, the other end of each first copper pipe 52a is enlarged in diameter using a special tool.

[0075] Next, the second copper pipe 52b of the first refrigerant piping 51 and the second copper pipe 52b of the second refrigerant piping 53 are positioned with support brackets 41 so that one end of each is facing the other end of the first copper pipe 52a, and each second copper pipe 52b is inserted inside the enlarged portion of each first copper pipe 52a.

[0076] In this case, the nitrogen gas cylinder 45 and the nitrogen gas blow device 1 of this embodiment are pre-installed on the first floor surface of the building structure 40.

[0077] Next, the gas supply port 46 of the nitrogen gas cylinder 45 is connected to the plug (point A in Figure 1) of the nitrogen gas inlet 11 of the device body 2 via the socket of the first pressure-resistant hose 15, one end of the second pressure-resistant hose 16 is connected to the socket of the first nitrogen gas outlet 12 of the device body 2 via the plug, and one end of the third pressure-resistant hose 17 is connected to the socket of the second nitrogen gas outlet 13 via the plug.

[0078] Next, the second pressure-resistant hose 16 is extended to one end of the first copper pipe 52a of the first refrigerant piping 51, and the other end of the second pressure-resistant hose 16 is inserted into the opening at one end of the first copper pipe 52a (point B in Figure 1). Also, the third pressure-resistant hose 17 is extended to one end of the first copper pipe 52a of the second refrigerant piping 53, and the other end of the third pressure-resistant hose 17 is inserted into the opening at one end of the first copper pipe 52a (point C in Figure 1).

[0079] Next, the other end of the first control wire 25 of the main body of the device 2 is connected to the first refrigerant pipe 51 (point D in Figure 1) via a clip 30, the other end of the second control wire 26 is connected to the second refrigerant pipe 53 (point E in Figure 1) via a clip 31, and the other end of the third control wire 27 is connected to the support bracket 41 of the frame 40 (point F in Figure 1) via a clip 32.

[0080] Next, the circuit breaker 19 on the main unit 2 is turned ON to enable AC100V power supply to the first solenoid valve 5 and the second solenoid valve 8. Then, the manual / automatic selector switch is operated to select manual or automatic operation, and the timer is operated to set the nitrogen gas blowing time.

[0081] Next, the clip 34 at one end of the hand control wire 33 of the welding-side hand control means 22 is connected to the support fitting 41 (point G in Figure 1), and the clip 35 at the other end is connected to the first refrigerant pipe 51 (point H in Figure 1).

[0082] As a result, the connection between the positive and negative sides of the control circuit 23 of the main unit 2 of the device is closed via the hand control wire 33, causing the first solenoid valve 5 to open. Nitrogen gas is then supplied from the nitrogen gas cylinder 45 to the inside of the first copper pipe 52a of the first refrigerant piping 51 via the first pressure-resistant hose 15, branch pipe 14, first solenoid valve 5, and second pressure-resistant hose 16. This nitrogen gas is then discharged from the other end of the second copper pipe 52b through the inside of the first copper pipe 52a and the second copper pipe 52b, filling both copper pipes 52a and 52b with nitrogen gas. This initiates the nitrogen gas blowing operation, which replaces the air inside both copper pipes 52a and 52b with nitrogen gas.

[0083] Then, while maintaining this state, oxygen gas and acetylene gas are supplied to the torch and burned to preheat the outer circumference of the joint between the two copper pipes 52a and 52b in the circumferential direction, melting the brazing material and pouring it into the joint between the two copper pipes 52a and 52b. The ends of the two copper pipes 52a and 52b are then joined by cooling the joint by appropriate means. By performing this operation continuously on multiple copper pipes 52, a first refrigerant piping 51 of a predetermined length consisting of multiple copper pipes 52 is constructed in the ceiling portion of the building structure 40.

[0084] Then, by removing the clip 35 of the control wire 33 from the first refrigerant pipe 51, the power supply to the first solenoid valve 5 is stopped, closing the first solenoid valve 5 and stopping the supply of nitrogen gas from the nitrogen gas cylinder 45 to the first refrigerant pipe 51.

[0085] Next, connect the clip 36 of the control cable 33 to the second refrigerant pipe 53 (point J in Figure 1).

[0086] As a result, the connection between the positive and negative sides of the operating circuit 23 of the main body of the device 2 is closed via the clip 34, causing the second solenoid valve 8 to open. Nitrogen gas is then supplied from the nitrogen gas cylinder 45 to the inside of the first copper pipe 52a of the second refrigerant piping 53 via the first pressure-resistant hose 15, branch pipe 14, second solenoid valve 8, and third pressure-resistant hose 17. This nitrogen gas is then discharged from the other end of the second copper pipe 52b through the inside of the first copper pipe 52a and the second copper pipe 52b, filling both copper pipes 52a and 52b with nitrogen gas. This initiates the nitrogen gas blowing operation, which replaces the air inside both copper pipes 52a and 52b with nitrogen gas.

[0087] Then, while maintaining this state, oxygen gas and acetylene gas are supplied to the torch and burned to preheat the outer circumference of the joint between the two copper pipes 52a and 52b in the circumferential direction, melting the brazing material and pouring it into the joint between the two copper pipes 52a and 52b. The ends of the two copper pipes 52a and 52b are then joined by cooling the joint by appropriate means. By performing this operation continuously on multiple copper pipes 52, a second refrigerant piping 53 of a predetermined length consisting of multiple copper pipes 52 is constructed in the ceiling portion of the building structure 40.

[0088] Then, by removing the clip 36 of the control wire 33 from the second refrigerant pipe 53, the power supply to the second solenoid valve 8 is stopped, closing the second solenoid valve 8 and stopping the supply of nitrogen gas from the nitrogen gas cylinder 45 to the second refrigerant pipe 53.

[0089] In the nitrogen gas blowing device 1 of this embodiment, configured as described above, nitrogen gas can be supplied from the nitrogen gas cylinder 45 to the first refrigerant pipe 51 via the first solenoid valve 5 by connecting the clip 34 at one end of the control wire 33 to the support bracket 41 and the clip 35 at the other end to the first refrigerant pipe 51. Furthermore, nitrogen gas can be supplied from the nitrogen gas cylinder 45 to the second refrigerant pipe 53 via the second solenoid valve 8 by detaching the clip 34 of the control wire 33 from the first refrigerant pipe 51 and connecting the clip 36 to the second refrigerant pipe 53. Therefore, it is not necessary for the operator to return to the position of the device body 2 each time the connection point changes to supply and stop the supply of nitrogen gas, allowing for efficient nitrogen gas blowing operations and significantly increasing the efficiency of the refrigerant pipe 50 connection work.

[0090] Furthermore, when the joining of the copper pipe 52 of the first refrigerant pipe 51 and the joining of the copper pipe 52 of the second refrigerant pipe 53 are performed independently, the supply and stopping of nitrogen gas from the nitrogen cylinder 45 to the first refrigerant pipe 51 and the supply and stopping of nitrogen gas to the second refrigerant pipe 53 can be controlled simply by connecting and disconnecting the clip 35 of the hand control wire 33 to the first refrigerant pipe 51 and the clip 36 to the second refrigerant pipe 53. This significantly reduces the time and effort required to change the setup when moving from the joining of the first refrigerant pipe 51 to the joining of the second refrigerant pipe 53, thereby greatly increasing work efficiency.

[0091] Furthermore, since the operating times of the first solenoid valve 5 and the second solenoid valve 8 can be set by a timer, nitrogen gas will not be blown into the copper pipe 52 of the first refrigerant pipe 51 or the copper pipe 52 of the second refrigerant pipe 53 more than necessary, thereby reducing nitrogen gas consumption.

[0092] Furthermore, a switch allows for automatic and manual operation of the first solenoid valve 5 and the second solenoid valve 8, enabling the worker to perform the joining work under conditions that are convenient for them, thus accommodating various workers with different skill levels.

[0093] Furthermore, since it uses DC 6V as the operating power supply, the risk of electric shock to workers at the site where the refrigerant piping 50 is joined can be made extremely low, thus ensuring the safety of the workers.

[0094] Furthermore, since it is not necessary to return to the location of the nitrogen gas cylinder 45 and operate the main unit 2 to supply or stop the supply of nitrogen gas from the nitrogen gas cylinder 45, the installation location of the nitrogen gas cylinder 45 is not restricted, and it can be applied to various sites with different conditions.

[0095] Furthermore, since blowing operations can be performed individually on the first refrigerant piping 51 and the second refrigerant piping 53, various configurations can be adopted depending on the condition of the installation location of the refrigerant piping 50, such as performing work on the second refrigerant piping 53 after the work on the first refrigerant piping 51 is completed, or performing work on the first refrigerant piping 51 and the second refrigerant piping 53 simultaneously, thereby increasing versatility.

[0096] Furthermore, even when the connection points are spread over a wide area, there is no need to extend the hand control cable 33. The operator can simply hold the hand control cable 33 by hand and move to the connection point, thus enabling work on multiple connection points and expanding the work range.

[0097] In the above explanation, the third operating wire 27 of the device body side operating means 21 is connected via clip 32 to the support fitting 41 which is electrically connected to the metal parts of the frame 40 such as beams and columns, and the hand operating wire 33 of the welding side hand operating means 22 is connected via clip 34. However, if the columns, beams, etc. are embedded inside concrete, an anchor can be driven into the concrete to electrically connect the anchor to the column, beam, etc. inside the concrete, and the third operating wire 27 can be connected to this anchor via clip 32, and the hand operating wire 33 can be connected via clip 34.

[0098] Furthermore, in this embodiment, the nitrogen gas blowing device 1 of the present invention was applied to the blowing of nitrogen gas into the refrigerant piping 50, but the nitrogen gas blowing device 1 of the present invention may also be applied to the blowing of other inert gases, and the same effects will be obtained in that case as well. [Explanation of symbols]

[0099] 1. Nitrogen gas blowing device 2. Main unit of the device 3. Control Box 5. First solenoid valve 6 Inlet 7 Outlet 8. Second solenoid valve 9 Inlet 10 Outlet 11. Nitrogen gas inlet 12. First Nitrogen Gas Outlet 13. Second Nitrogen Gas Outlet 14 Branch pipes 14a proximal end 14b Branch End 14c branch end 15. First pressure-resistant hose 16. Second pressure-resistant hose 17. Third pressure-resistant hose 19. Circuit breaker 21 Device main unit side operation means 22 Welding-side manual operating means 23 Operation circuit 25 1st operation line 26 2nd operation line 27 3rd operation line 30 clips 31 clips 32 clips 33. Handheld control lines 34 clips 35 clips 36 clips 40 skeleton 41 Support bracket 45 Nitrogen gas cylinders 46 Gas supply port 50 Refrigerant piping 51. First refrigerant piping 52 Copper tube 52a First copper pipe 52b Second copper pipe 53 Second refrigerant piping 55 Outdoor unit

Claims

1. In construction work to install refrigerant piping in the ceiling portion of the structural frame of a steel-frame, reinforced concrete, or steel-reinforced concrete building, when extending the first or second refrigerant piping by joining means such as brazing or welding, a nitrogen gas blow device is provided to supply nitrogen gas to the inside of the first or second refrigerant piping. A nitrogen gas blowing device characterized by comprising: a device body for supplying and stopping nitrogen gas into the first refrigerant piping or the second refrigerant piping; a device body-side operating means, one end of which is electrically connected to the operating circuit of the device body and the other end of which is electrically connected to the building frame, the first refrigerant piping, and the second refrigerant piping; and a welding-side operating means, at the welded joint of the first refrigerant piping and the second refrigerant piping, with one end of a hand-operated wire electrically connected to the building frame and the other end of which is electrically connectable to the first refrigerant piping or the second refrigerant piping.

2. The main body of the apparatus comprises a first solenoid valve for supplying and stopping nitrogen gas to the first refrigerant piping, a second solenoid valve for supplying and stopping nitrogen gas to the second refrigerant piping, and the operating circuit for opening and closing the first and second solenoid valves. The nitrogen gas blow apparatus according to claim 1, characterized in that the operating means on the apparatus body side and the welding side hand-operated means are provided between the operating circuit and the chassis, the first refrigerant piping, and the second refrigerant piping.

3. The operating means on the main body of the device comprises a first operating wire, one end of which is electrically connected to the positive side of the operating circuit and the other end of which is electrically connected to the first refrigerant piping; a second operating wire, one end of which is electrically connected to the positive side of the operating circuit and the other end of which is electrically connected to the second refrigerant piping; and a third operating wire, one end of which is electrically connected to the negative side of the operating circuit and the other end of which is electrically connected to the building body. The nitrogen gas blow apparatus according to claim 2, characterized in that the welding-side manual operating means comprises a manual operating wire, one end of which is electrically connected to the building structure and the other end of which is electrically connected to the first refrigerant piping or the second refrigerant piping.

4. The nitrogen gas blow apparatus according to claim 3, characterized in that clips are provided at both ends of the first operating wire, the second operating wire, and the third operating wire, and clips are provided at both ends of the hand-operated operating wire.

5. The nitrogen gas blow apparatus according to any one of claims 1 to 4, characterized in that a DC 6V voltage is applied to the operating circuit of the apparatus body.

6. The nitrogen gas blowing apparatus according to claim 2, characterized in that the operating circuit of the main body of the apparatus incorporates a circuit that allows setting the operating time of the first solenoid valve and the second solenoid valve, and selecting between manual and automatic operation.

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