EXPANSION JOINT PRODUCTION
A STEP-BY-STEP GUIDE MR-11w

1. Rubber compounds are comprised of polymers, reinforcing fillers, antioxidants, antiozonants, etc. Each ingredient is meticulously weighed to assure uniformity.

2. Each rubber batch is carefully mixed for a specific time at controlled temperatures in our automatic mixer.

3. The mixed composite is discharged in clumps which are then transferred to a mill to create a more workable material.

4. The cure is added to the rubber on a powerful 60 inch mill, which completes the mixing before the material is cut into rough sheets and prepared for the calender.

5. The calender process is the most critical phase of fabric preparation.

6. Large steel rollers force rubber into the nylon, polyester or Kevlar tire cord reinforcement or into smooth rubber sheets. Thickness tolerances are maintained to thousandths of and inch.

7. Milled rubber may also pass through an extruder that discharges uncured rubber strips in geometric shapes. These strips are used to smooth transition contours in arches and flanges and as fillers.

8. The bias cutter allows the technician to cut fabrics at precise angles specified by engineering to control swell, elongation and burst in designated products.

9. Every product design specifies materials to be used in each layer. Here, flange reinforcement is stamped to size on a "clicker" press.

1. Expansion joint arches are formed over removable rubber inserts. If arches are very small or oversized, we use plaster arch forms that can be broken out after the expansion joint is cured.

2. When the expansion joint nears completion, the exterior sheath is pulled up to form the cover on the back of the flange.

3. Before the steel flange forms can be bolted or clamped in position, the perimeter is carefully trimmed.

4. Products are formed on a mandrel. Its shape fits the inside contour of the product. Concentric reducers are built with the small and large diameters on opposite ends, joined by a cone shaped transition section.

5. Steel hoops are locked into the base of the arch by back wrapping the reinforcing fabric.

6. To prevent swelling, large diameter expansion joints are generally reinforced with high-tensile wire or steel hoops. This process requires precise application of both wire and uncured rubber fillers.

7. Cover application is the final stage of reducer body building.

8. Building eccentric reducers becomes more difficult because the mandrel rotates off center. This varies the working distance between the product and the assembler, and requires exceptional coordination.

9. Once assembled, products are cured in large pressurized steam chambers called autoclaves. To prevent rubber from expanding and changing shape, the entire carcass is wrapped with layers of strong nylon tape.

10. When the nylon body wrap is finished, the steel mold plates that form the rubber flanges are bolted in place to retain the flanges during the curing process.

11. Hose construction is simpler when there's no arch to build over. Generally, sections are longer and require more layer of longitudinal reinforcement to minimize elongation.

12. Virtually every pressure and suction hose is wire reinforced to prevent swelling or collapse.

1. Although every assembly follows similar procedures, the complexity of each job varies with its shape, size and pressure requirements. Shown here are 96 inch diameter joints under construction.

2. Like other manufacturers, we build each product with uncured rubber. Unlike other manufacturers, we vulcanize every finished piece in our customized autoclaves. Pressurized steam curing is far superior to baking, and we can accommodate pieces up to 18 feet in diameter.

3. Our manufacturing facility is self-sufficient. This enables us t turn orders around quickly and economically. Our heavy equipment includes oxyacetylene and plasma burning tables; iron workers, punch and drill presses; automatic band saws and welding equipment. We manufacture our own tooling, steel backup rings, reinforcing hoops and control rod assemblies.

4. Our radial drill presses can drill holes as large as three inches in diameter. Here, backup rings are tacked together in stacks to assure that drilling is uniform.

5. Every flange hole is located and marked with steel templates, and then drilled straight and clean with hollow drill cutters.

6. During final inspection, all rubber parts are trimmed, cleaned and painted. Finally, ductile iron or steel backup rings are attached to the flanges and checked for hole alignment.

7. Hydro testing is another phase and all products undergo one final quality control evaluation before shipment. Once approved, large expansion joints are packed securely in wood spool crates for added protection on their journey.