Sealing and Insulation in Rubber and Tyre Manufacturing

Rubber and tyre manufacturing combines high-temperature steam, heavy mechanical loads and a product that is itself an elastomer. The sealing and insulation requirements are driven by the curing process: press platens and autoclaves cycle hot continuously, and every cycle is an opportunity to lose heat or leak steam.

The curing press is the centre of the problem

Vulcanising presses and autoclaves hold heat and pressure for each cure, then open. That cycling is harder on materials than steady-state running — seals relax and recover repeatedly, insulation is heated and cooled, and bolt loads work loose. A joint that holds perfectly at constant temperature can weep as soon as it starts cycling.

The economic point is that heat lost from a press is paid for on every cycle, not once. Platen edges, steam headers feeding the presses, and the pipework between them are usually where the recoverable loss sits, and they are often the least insulated parts because they are awkward to lag around.

Steam system sealing

Press steam service is the main gasket and packing duty. On steam valves and pumps, graphite packing with Inconel wire handles the temperature and the cycling well — the graphite conducts heat away from the shaft and the wire reinforcement holds the ring together under repeated load changes.

For flanged joints on steam headers, non-asbestos jointing sheet is the standard. Use the thinnest grade that will conform to the flange faces and re-torque after the first heat cycle — on cycling service this is not optional, and skipping it accounts for most of the weeping joints found on press steam lines. The bolt torque and sequence guide covers the method.

Insulating presses and headers

Glass wool covers steam headers and distribution pipework. Around the presses themselves, where space is tight and the shape is irregular, rope and tape lagging works better than bulk material — pack it into the gaps rather than bridging over them. The lagging guide covers technique, and the heat loss calculator will quantify what an uninsulated header costs per month.

Mills, mixers and the mechanical side

Internal mixers, two-roll mills and extruders bring a different problem: heavy loads, cooling water circuits and carbon black dust. Pump glands on cooling circuits are straightforward duty, but the dust is abrasive and works into seals from outside. Check shaft condition at every repack rather than fitting progressively harder packing, which scores the shaft further.

Keeping compound clean

Carbon black and compounding dust migrate through a plant and contaminate light-coloured compound. PVC strip curtains separate mixing areas from finishing and storage while leaving forklift and trolley access open, and they help hold temperature in conditioned areas. The strip curtain calculator sizes a doorway.

Release and heat-resistant surfaces

Where uncured compound must not stick — transfer surfaces, liners, heat-sealing work — PTFE coated fibreglass fabric provides a release surface that tolerates the temperature. For heat shielding around presses and hot lines, the coated fabric comparison covers which coating suits which duty.

What we would ask before quoting

• Press and autoclave operating temperature and pressure, and cycle frequency.
• Which steam lines and headers are currently uninsulated or poorly lagged.
• Pump and valve shaft and stuffing box dimensions on steam and cooling circuits.
• Flange sizes and current gasket grades on press steam service.
• Shutdown windows, since press work is rarely possible during production.

Tell us which presses are costing you most in fuel or downtime and we will start there rather than quoting the whole plant.