Rubber expansion joints manufacture

The temperature ratings and application limits of certain rubbers used in the manufacture of rubber expansion joints are given in Table 7.1. 

In the manufacture of rubber expansion joints, material selection and formulation should be considered against the constructional characteristics required in the product. Rubbers, compounds, adhesives and solvents are all thoroughly checked for quality, to avoid possible layer separation or delamination of the layers while the joints are being built. 

When minimum movement capability is required, the arch is sometimes filled with soft rubber using a suitable adhesive. The maximum amount of movement (axial extension and compression, lateral deflection and angular rotation) that an expansion joint is capable of absorbing is called the rated movement. This rating depends on various factors, such as the size of the expansion joints, the thickness of the tube, arch or convolution, and the type and properties of rubber compound and fabric used in construction. Rated movements are established by manufacturers of expansion joints theoretically, or are based on actual load deflection curves of each size of joint. Rubber expansion joints are generally subjected to hydraulic and vacuum tests at 1.5 times the operating pressure. No internationally accepted standard technical specification for rubber expansion bellows is available, since they are mostly custom built to specific operational requirements. The Expansion Joint Manufacturers Association in New York has laid down standards for rubber expansion joints, which are called EJMA standards [2]. 

When bonding compounded rubber to fabric, for the manufacture of fabric reinforced expansion joints in the chemical plant piping systems, mechanical anchoring between cotton/Nylon/fibre and compounded rubber should be sufficient to ensure good adhesion. Synthetic fibres require treatment with chemical coatings to secure maximum adhesion and bond [8, 9]. 

Component Manufacturer. Designs and assembles systems that may include rubber parts (e.g., mechanical seals, expansion joints, valves). 

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