System for supervising piping work

Abstract: A system of the invention for supervising piping work comprises a machine for performing piping work such as welding of pipes or tightening of pipe joints under predetermined conditions, check means for checking whether the piping work has been executed properly based on predetermined values of piping work conditions and actual piping work data, a host computer for accumulating the predetermined values of piping work conditions, the actual piping work data and the result of checking, and communication means for transmitting the predetermined values of piping work conditions, the actual piping work data and the result of checking.

Description: The present invention relates to a method of antomatically welding pipes. Machines for performing automatically welding of pipes under predetermined conditions, i.e., automatic welders, are conventionally used, for example, in semiconductor manufacturing plants. The piping work is performed at the actual site and completed at the site, and nothing whatever is known about a method of superposing the piping work including accumulation of data. The gastightness of the piping system is of extreme importance in semiconductor manufacturing plants wherein hazardous gases are used; a fault in the piping work could lead to an accident. However, after the piping work has been completed, no record is conventionally left as to what particular conditions are employed for the piping work of particular portions of the piping system, consequently entailing the problem that it is impossible to realize whether the piping work has been executed properly. AU-B 571 116 discloses a method of continuously measuring the machine profile of a weld on the internal surface of a welded tube. However, according to the prior art method the welding surfaces are only checked after the machining to produce a certain profile of the weld. Thus, the welding process cannot be influenced and accordingly this method also has the before mentioned disadvantages. An object of the present invention is to provide a piping work supervising system which is capable of precluding accidents in piping due to faulty piping work. This object is solved by the method of claim 1. The method of the invention checks during the welding process, whether the welding work has been executed properly, and accumulates the predetermined values of the welding work conditions, the actual welding working data and the results of checking. This precludes accidents in the piping due to fault in the welding work, further making it possible to pick up the main portions to be checked from among the portions of the piping worked on with reference to the actual welding work data when piping is to be inspected, and to inspect the main portions only, which are smaller in number than all the worked-on portions. The method also inquires, whether the electrode of the welder is to be replaced. If the welder is set at a free welding frequency of for example 50 times until the replacement of the electrode, the number of times is conducted following the replacement is automatically counted, and an alarm for the replacement of the electrode is given on completion of the 50 th welding operation. This eliminates unacceptable welds due to a fault in the electrode to improve the reliability of the welding operation. Preferably, the communication means is on a spread-spectrum communication system. This system is such that the signal, subjected to usual phase modulation, is then multiplied by a special spreading code at the transmitter side, and multiplied by the same spreading signal at the receiver side to retrieve the original signal. With this system, the signal is spread over a wider frequency range and therefore lower in electric power density, i.e., in electric power per unit frequency. Accordingly, the system has the advantage of being less affected by the noise of the work site. Preferably, a host computer is connected to the processor by a local area network (LAN) for accumulating the welding data and the result of checking. This system ensures a proper welding operation, consequently precluding accidents in the piping due to faulty welding. Furthermore, reference to the welding data and the result of checking accumulated in the host computer leads to facilitated supervision for the maintenance of the welded portions. It is desired that the host computer be connected to a plurality of terminal computers by a network. Any of the terminal computers then allows the work supervisor access to the welding record, while the supervisor can issue a command from the terminal computer to the data processor via the host computer when the work is to be interrupted or the work conditions are to be altered. Thus, the networked system enables the supervisor to recognize reliable execution of the welding operation at a location remote from the work site. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of piping work supervising system of the invention, i.e., a welding system; FIG. 2 is a time chart showing the welding conditions for a welder for use in the welding system; FIG. 3 is a block diagram showing a modification of the welding system; and FIG. 4 is a flow chart showing the main routine of checking portion of the welding system; Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a piping work supervising system of the invention for use as a pipe welding system. With reference to the drawing, the piping work supervising system for a pipe welding operation comprises an automatic welder 1 for piping, a welding data output device 2 for delivering predetermined values of welding conditions for the welder 1 and actual welding data, a welding data processor 3 for checking whether or not output values from the output unit 2 are proper and accumulating the welding data and the result of checking, and a host computer 4. The welder 1 is a known one (for example, MODEL 207 of Arc Machine Co.). The welder is set on a pipe at the joint portion thereof to be welded, and the switch is then turned on, whereupon the welder revolves around the pipe one turn to weld the pipe under the predetermined conditions. The welding conditions to be checked for judging whether a proper weld is formed include the welding time, welding current, welding voltage, speed of revolution and pressure of back-shielding gas during welding (pressure during welding). FIG. 2 shows an example of time chart of welding conditions. The welding conditions include a plurality of levels of short duration which are changed over from one to another. The chart shows that the welding current is 35 A for 0.1 second at level 1, 40 A for 0.5 second at level 2, 42 A for 0.5 second at level 3, 40 A for 0.5 second at level 4, 33 A for 0.4 second at level 5, 30 A for 0.3 second at level 6, and 20 A for 0.3 second at level 7, further showing that the speed of revolution is 30 r.p.m. for 2.0 seconds at level 1 through level 5, 26 r.p.m. at level 6 and 15 r.p.m. at level 7. The welding data output device 2 has a welder power supply incorporated therein, a printer output unit 5 for outputting the predetermined condition values as to the welding time, welding current and speed of revolution for each level as 8-bit parallel data, and a pen recorder output unit 6 for outputting the actual analog values of welding current, welding voltage and speed of revolution during welding. The welding data processor 3 comprises a parallel/serial converter 7 for converting the predetermined condition values delivered from the output device 2 in the form of 8-bit parallel data to serial data, an A/D converter 8 for converting the actual analog values delivered from the output device 2 to digital data, a check result output unit (I/O unit) 9 for checking whether the welding data is proper and delivering the result, a memory 10 for storing the predetermined values of the welding conditions, the actual welding data and the check result, a wireless LAN transmitter-receiver 11 for transferring data to and from the host computer 4 and a serial interface 12 for delivering welding data to the transmitter-receiver 11. The host computer 4 is connected to a plurality of terminal computers 13 by a network. The host computer 4 is also provided with a wireless LAN transmitter-receiver 14. The check result output unit 9 of the welding data processor 3 indicates the check result and actuates an alarm buzzer 15 when the weld is unacceptable. The memory 10 of the processor 3 temporarily stores data including the welding address, work executor's code, predetermined condition values, welding current, welding voltage, revolution speed, internal pressure during welding, welding date and time and check result. Such data is transmitted to the host computer 4 via the transmitter-receivers 11, 14 and stored in the computer 4. The wireless LAN transmitter-receivers 11, 14 exchange spread-spectrum wireless communications and can transfer data within the range of up to about 200 m even with use of a feeble current. Other system is of course usable for the transmitter-receivers 11, 14. A bar code 16 representing a welding address and executor's code is provided for the portion to be welded. These welding address and executor's code are read by a bar code scanner 17 and sent by a bar code reader 18 to the serial interface 12 of the welding data processor 3. The internal pressure of the welder 1 during welding is measured by a pressure sensor 19 and sent to the A/D converter 8 of the processor 3. Instead of providing the bar code 16, the welding address and the executor's code may be input to the processor 3 by the host computer 4. Since the host computer 4 is connected to the terminal computers 13 by a network, any of the terminal computers 13 allows the work supervisor access to the welding record, while the supervisor can issue a command from the terminal computer 13 to the welding data processor 3 via the host computer 4 when the work is to be discontinued in an emergency or the welding conditions are to be altered. Thus, the networked system enables the supervisor to recognize reliable execution of the welding operation at a location remote from the welding site. The parallel/serial convertor 7 and the A/D converter 8 of the welding data processor 3, which are intended to conform to the data output mode of the output device 2, can be modified or eliminated in conformity with the data output mode of the device 2. FIG. 3 shows such a modification. Throughout FIGS. 1 and 3 like parts are designated by like reference numerals and will not be described repeatedly. With reference to FIG. 3, a welding data output device 20 has incorporated therein a power supply for the welder 1. Predetermined condition values as to the welding time, welding current and speed of revolution at each level, and actual values of welding current, welding voltage and speed of revolution during welding are all delivered in the form of digital values through a digital interface 22. In corresponding relation with the device 20, a welding data processor 21 has a digital interface 23 in place of the parallel/serial converter 7 and the A/D converter 8. The digital values are transferred from the output device 20 to the processor 21 by serial and/or parallel signals. The main routine of the welding data processor 3 will be described next with reference to FIG. 4. The power supply is turned on (step 1), whereupon the system is initialized (step 2). The start key is then pressed (step 3), whereupon the welding address and executor's code are read from the bar code (step 4). Alternatively, the welding address and the executor's code may be input from the host computer in step 4. The address and the code are compared with the welding address and executer's code stored in the memory (step 5) and checked for a match (step 6). When they do not match the stored data, lack of the corresponding address is displayed on the check result output unit, and the result is output to the host computer, whereupon the sequence returns to step 3 (step 7). If a match is obtained in step 6, the predetermined condition values for each level delivered from the welder are read (step 8), and a welding start signal is output (step 9), whereby a welding operation is started. The actual values of welding current, welding voltage and revolution speed at each level delivered from the welder are read (step 10). These actual values of current, voltage and speed are compared with the respective predetermined condition values read in step 10 (step 11), and checked for matching (step 12). If the read values are found to match the predetermined values, the check result output unit displays "OK" (step 13). If otherwise, the check result output unit shows "BAD" (step 14). Regardless of the check result, the welding address, executor's code, welding date and time, welding data, predetermined welding condition values and check result are fed to the host computer (step 15). Step 10 through step 15 are repeated for every level of the welding conditions shown in FIG. 2, and an inquiry is made as to whether the welding condition checking for the final level has been completed (step 16). When the inquiry is answered in the affirmative, the sequence returns to step 3. In this way, the welding conditions are checked at every level to ensure a reliable welding operation. Step 12 also inquires whether the electrode of the welder is to be replaced. If the welder is set at a welding frequency of 50 times until the replacement of the electrode, the number of times the welding operation is conducted following the replacement is automatically counted, and an alarm for the replacement of the electrode is given on completion of the 50th welding operation. This eliminates unacceptable welds due to a fault in the electrode to improve the reliability of welding operation.

Claims: A method for automatically welding pipes, characterized by the steps of outputting predetermined values of welding conditions for the welder (1) and actual welding data by a welding data output device (2), checking whether output values from the welding data output device (2) are proper and temporarily accumulating the welding data and the results of checking by means of a welding data processor (3), wherein the welder (1) is set at a welding frequency of predetermined times until the replacement of an electrode of the welder (1), the number of times the welding operation is conducted following the replacement is automatically counted, and an alarm for the replacement of the electrode is given on completion of the last welding operation. A method according to claim 1, wherein data between a host computer (4) and the processor (3) are communicated by a spread-spectrum system. A method according to claims 1 or 2, wherein a host computer (4) is communicating with a plurality of terminal computers by a network.

Inventors: DOHI RYOSUKE, FUKUDA HIROYUKI, IDETA EIJI, MOROKOSHI HIROSHI, NOBUKAZU IKEDA, OHMI TADAHIRO, DOHI, RYOSUKE, FUKUDA, HIROYUKI, IDETA, EIJI, MOROKOSHI, HIROSHI, OHMI, TADAHIRO, DOHI, RYOSUKE, C/O FUJIKIN INCORPORATED, Fukuda, Hiroyuki, c/o FUJIKIN INCORPORATED, IDETA, EIJI, C/O FUJIKIN INCORPORATED, Morokoshi, Hiroshi, c/o FUJIKIN INCORPORATED, NOBUKAZU IKEDA, C/O FUJIKIN INCORPORATED
Applicants: FUJIKIN KK, OHMI TADAHIRO, FUJIKIN INCORPORATED, OHMI, TADAHIRO
Application year: 1997
Main classification: B23K31
IPC codes: F16L13, F16L1, B23K31