Troubleshooting of the gas separation valve of the

2022-09-22
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Troubleshooting of the air separation valve of Heidelberg four machine automatic paper feeder

a second-hand Heidelberg four-color offset press in our factory once suffered from insufficient suction of the automatic paper feeder and the paper suction of the paper feeder did not export. The top three markets were Hong Kong, China, the United States and Vietnam respectively. At that time, the production task was very urgent, so it was not removed in time for inspection and maintenance. For this reason, it was operated for a period of time, and finally there was the fault that the air distributing valve failed and the suction nozzle could not breathe. Therefore, the on-site emergency repair first removed the gas distributing valve for inspection. After the valve body was disassembled, it was found that a 30mm long section of the outer circular surface of the valve body (valve body diameter 42mm, cast copper material) was seriously ground and "burned", and there were grooves on the worn surface. In this case, either replace the valve body or repair the damaged surface so that the valve body can normally match with the valve sleeve

because there are no spare parts, I decided to adopt repair welding first. If copper brazing is used for repair, the workpiece may deform during heating brazing. If tin welding is used for repair, it will not deform. It is easy to operate, but the hardness cannot be the same as that of copper. However, as an on-site emergency treatment, it can be used. For this reason, I first choose to repair with solder. Rosin is used as the flux for tin welding (better than solder paste), and 150W electric iron is used to heat it. After reaching the limit temperature, the welding can be started. After welding the tin layer, it should be higher than the original cylindrical size, and then clamp the repaired valve body on the lathe to finish turning and sanding the welding layer to make it reach the normal size. The treatment of the valve sleeve is just to clamp the valve sleeve on the lathe and sand the damaged part with 0 # emery cloth. In this way, the repair process is completed in a short time, and the machine is reinstalled for operation. The performance is normal and meets the use requirements. It shows that this method is feasible

in addition to the above treatment is feasible, there are also wear treatments like the above. If conditions permit, they can also be repaired by adhesive coating technology. Adhesive coating technology has the advantages of convenient operation, wide applicability, good combination of coating and matrix, fast repair speed, good quality and low cost. The adhesive used for bonding includes wear-resistant agent, filler, emergency repair agent that provides reliable data support in terms of safety performance, etc. the adhesive is generally similar to mud, and is divided into two components a and B. when using, mix and mix the two groups A and B according to the specified proportion before coating (the coated surface should be cleaned with acetone before coating), and turn after curing to restore to the original size. The hardness of this kind of adhesive after curing is almost the same as that of copper. Imported adhesives such as the Belzona series of the United States and domestic ones with ts111 brand are of good quality. Available for peer selection

Guangdong printing, 2004, issue 5, author: Chen Jinru

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