Many technological processes will be involved in the production of a qualified rubber expansion joint, generally the process formanufacturing of rubber expansion joint can be concluded into several steps: rubber material preparation→rubber sheet extrusion→cutting and splicing→moulding→vulcanization→inspection→assemble →pressure testing→package→storage. Let me tell you more details about rubber expansion joints manufacturing process.
Lanphan staffs working in the factory, manufacturing a DN2.8m rubber expansion joint
Rubber material preparation and rubber sheet extrusion: this is one of the most important process for rubber expansion joint manufacturing, rubber ingredient must be accurate, rubber mixing process must in according with regulations. For the rubber sheet extrusion of rubber expansion joint manufacturing, the rubber sheet must have no bubbles and smooth in surface, thickness should be uniformed.
Cutting and splicing: according to the structure requirement of rubber sphere, the fabric should be cut in 45°-50°.
Moulding: moulding process: inner rubber layer→first fabric layer→second fabric layer→n layer→medium rubber layer→n layer→last fabric layer→reinforcing spool of straight pipe→turn over rubber edge→outer rubber layer.
Vulcanization: vulcanization is the key factor that determines the quality of a rubber expansion joint. Henan Lanphan has the largest vulcanizing tank in Asia: 5m*12m, right time, temperature, pressure is very important for the manufacturing of rubber expansion joint.
Surface inspection: four items should be checked on inner rubber layer and outer rubber layer. The items should not exist on the inner rubber layer, but for outer rubber layer, we should in according with following standards:
1.Bubbles. Area should not exceed 100 square millimeter, two flaw distance no less than 50mm.
2.Scar and impurity: depth should not exceed 0.5mm, no more than 2 places.
3.External damage: depth should not exceed 0.5mm, area should not exceed 100 square millimeter, no more than 2 places.
4.Crack, spongy and holes: not allowed on the outer rubber layer.
Assemble: after surface inspection, workers assemble flanges to the rubber expansion joint.
Quality inspection: quality inspection includes hydraulic test, resistance to vacuum, displacement of the performance, rubber physical properties, thickness and the strength and other quality test.
Package: Lanphan rubber expansion joint is covered with plastic thin film, then packaged in cartoon box or wooden cases for shipping.
Storage: please avoid strong sunshine, rain and snow, scratch, and away from heat source at least 1m, temperature between -5℃-30℃.