[Q&A Question 285] 2017.10.13

Use isolation media, remove the flange, replace the gasket, tighten the flange, and put it into use.

1. Open the bypass valve, close the inlet valve of the valve to be replaced, close the outlet valve, and hang a shutdown warning sign. Open the vent valve to release pressure until the pressure indicated by the gauge reaches zero. 2. Measure the flange dimensions with a ruler, use a compass to draw two concentric circles on the asbestos board with diameters equal to those of the flange’s inner and outer surfaces, and cut out the gasket with scissors. 3. Compare the newly manufactured gasket with the flange to check if they fit together. 4. Loosen the flange bolts: loosen the eight bolts on each side of the valve’s flanges, and then remove six bolts from each side (three on each side). Leave one bolt with its nut still in place on each flange to prevent the valve from falling. Remove the valve, and also take out the remaining two bolts. 5. Remove the old gasket, use a scraper to clean the flange surfaces, and ensure both flange surfaces are clean. 6. Align the valve in place, align the six bolts on each side of the valve (three on each side), and leave a gap. 7. Apply butter to the new gasket, use a crowbar to lift the flange, and install the new gasket. Install the remaining flange bolts on the fitting, tighten them diagonally using a wrench, and wipe them clean. 8. Close the drain valve, slightly open the upstream valve, and check for any leaks. Once no leaks are detected, open the downstream valve as well as the upstream valve, close the bypass valve, and hang up a warning sign indicating that the system is in operation. 9. Fill in the records, pack up the tools, and clean up the site.

1. Open the bypass valve, close the inlet valve of the valve to be replaced, close the outlet valve, and hang a shutdown warning sign. Open the vent valve to release pressure until the pressure indicated by the gauge reaches zero. 2. Measure the flange dimensions with a ruler, use a compass to draw two concentric circles on the asbestos board with diameters equal to those of the flange’s inner and outer surfaces, and cut out the gasket with scissors. 3. Compare the newly manufactured gasket with the flange to check if they fit together. 4. Loosen the flange bolts: loosen the eight bolts on each side of the valve’s flanges, and then remove six bolts from each side (three on each side). Leave one bolt with its nut still in place on each flange to prevent the valve from falling. Remove the valve, and also take out the remaining two bolts. 5. Remove the old gasket, use a scraper to clean the flange surfaces, and ensure both flange surfaces are clean. 6. Align the valve in place, align the six bolts on each side of the valve (three on each side), and leave a gap. 7. Apply butter to the new gasket, use a crowbar to lift the flange, and install the new gasket. Install the remaining flange bolts on the fitting, tighten them diagonally using a wrench, and wipe them clean. 8. Close the drain valve, slightly open the upstream valve, and check for any leaks. Once no leaks are detected, open the downstream valve as well as the upstream valve, close the bypass valve, and hang up a warning sign indicating that the system is in operation. 9. Fill in the records, pack up the tools, and clean up the site.

1. Reverse the process and vent: Check the process, switch it to the correct mode, open the vent valve, and release all pressure from the pipeline. 2. Remove the flange bolts: Loosen the flange bolts and use a crowbar to lift the flange so that the liquid inside the pipeline can flow into the drain bucket. Remove only the bolts that are facing you; do not remove all of them to avoid misalignment. 3. Remove the old gasket: Use a crowbar to pry open the flange and take out the old asbestos gasket, then clean the flange surface with a putty knife ； The waterline needs to be clean. 4. Making the gasket: Use a ruler to pass through the center of the flange, measure the outer diameter of the flange as well as the distance from the outer edge of the flange to the outer edge of the waterline step, and calculate the outer diameter of the gasket (the inner diameter is determined based on the valve specifications). Use a compass and scissors to create the flange gasket; the gasket should have a handle that is slightly longer than the maximum outer diameter of the flange. 5. Install the new gasket: Apply butter to both sides of the new gasket, place it inside the flange, ensuring it is centered without any deviation, and adjust it using the handle provided. 6. Tighten bolts: Tighten the bolts evenly in a diagonal pattern, ensuring that the gaps around the flange are roughly consistent. 7. Pressure testing procedure: Close the vent, slowly open the valve to conduct pressure testing; once no leaks are detected, open the valve fully to resume normal operation. 8. Clean up the site: collect tools, clean the area, and fill out the relevant documents.

Close the valves at both ends of the flange, drain the material from the pipe section (be careful to take precautions regarding flammable, explosive, or corrosive materials), and replace the gaskets

①The material, type, and dimensions of the gasket must meet the requirements； ②After removing the bolts, check that the flange sealing surface is free of defects; the sealing surface must be cleaned thoroughly ； ③The bolt should pass through 1/2 of the flange screw hole, or as much as will fit the gasket ； ④Place the gasket inside the flange surface ； ⑤The two flanges must be on the same center line ； ⑥Tighten the bolts on the diagonal, with 1.5 cm of protrusion at each end of the bolts ； ⑦Check that the gaps around the flange surface are all of equal size.

Before replacing the flange gasket, the pipeline section containing the gasket to be replaced must be isolated, and pressure must be released from that section.

Use isolation media, remove the flange, replace the gasket, tighten the flange, and put it into use.

1. The material, type, and dimensions of the gasket must meet the requirements； 2. After removing the bolts, check that the flange sealing surface is free of defects; the sealing surface must be cleaned thoroughly ； 3. The bolt should pass through 1/2 of the flange screw hole, or as far as the gasket will fit ； 4. Place the gasket inside the flange surface ； 5. The two flanges must be on the same center line ； 6. Tighten the bolts on the diagonal; it is advisable for the ends of the bolts to protrude by 1.5 cm ； 7. Check that the gaps around the flange surface are all of equal size.

1 1. Prepare the tools and manufacture new flange gaskets that meet the specifications. 2 Reverse the process to vent and relieve pressure. First, close the upper and lower valves, then open the vent valve. 3. Unscrew the flange screws and remove the old flange gasket. 4. Clean the flange surfaces thoroughly. 5. Install a new flange gasket, making sure it is aligned properly. 6. Tighten the screws in a diagonal pattern, ensuring they are even and properly compressed. 7. Reset the pipeline valves. 8. Clean up the site and collect tools and equipment