Polymer & Rubber
Process Overview
Polymer & Rubber — Process Overview
Polymer and synthetic rubber plants handle toxic, volatile monomers, sticky polymer slurries and latex, and acidic crumb-rubber slurries, often in large agitated vessels with significant shaft run-out. Toxic monomers need dual pressurised seals; agitators need seals with their own bearing support.
Primary Processes Covered:
- Polymerisation: PVC, polystyrene and other suspension or emulsion polymerisation in agitated autoclaves.
- Monomer handling & stripping: monomer feed and residual monomer stripping.
- Synthetic rubber: SBR / NBR latex coagulation and crumb handling.
- Natural rubber latex processing (latex transfer and concentration).
What seal is used on polymerisation reactor agitators?
Polymerisation autoclave agitators are typically fitted with a double cartridge mechanical seal with an integral bearing assembly, which supports the long agitator shaft and keeps the faces aligned despite run-out. A compatible barrier liquid (API Plan 53A or 54) held at least 1.4 bar above vessel pressure keeps monomer and polymer away from the faces.
Root-Cause Failure Analysis — Field Example
Symptom: Stripper bottoms pump seal leaks; faces glued by polymer after a shutdown.
├── Diagnostic Evidence Required:
│ ├── Is polymer deposited between and around the faces?
│ ├── Did barrier pressure fall below seal-chamber pressure during vacuum operation?
│ ├── Was the pump left full of slurry during the stop?
└── Engineered Solution:
├── Fit a dual balanced cartridge on Plan 53A rated for vacuum and pressure.
├── Keep barrier pressure ≥ 1.4 bar above seal-chamber pressure at all times.
├── Flush the pump casing before extended stops.
Frequently Asked Questions
Why are dual pressurised seals used on VCM and styrene pumps?
Vinyl chloride and styrene are toxic and volatile. A dual pressurised seal (Plan 53A) keeps the inboard faces in clean barrier liquid at higher pressure than the process, so monomer cannot escape to atmosphere.
Which faces suit crumb rubber slurry?
Crumb rubber slurries are sticky and mildly abrasive. Tungsten carbide vs. silicon carbide faces, springs kept out of the product and a clean flush keep the faces clear.
Request a Seal Selection
Send your equipment type, make and model, shaft size, speed, fluid, temperature and pressure to info@gipfelengg.com or use our enquiry form. Related: chemical plants, pharmaceutical (agitator seals). Gipfel Engineering (ISO 9001:2015, NSIC-registered MSME, Mumbai) designs and manufactures mechanical seals, seal support systems and process pumps.
Equipment solutions: Reactors & GLR · Autoclaves · Mixers.
Equipment Duty & Mechanical Seal Selection Matrix
Typical values for selection guidance only. Final selection is made against the equipment data sheet, monomer list and vessel design conditions.
| Equipment duty | Fluid | Typical temp. | Typical pressure (bar) | Seal arrangement | Faces / elastomer | Piping plan |
|---|---|---|---|---|---|---|
| Polymerisation Autoclave Agitator | Monomer slurry with polymerising beads | 70–135°C | Full vacuum to vessel design pressure (verify seal rating) | Double cartridge seal with integral bearing assembly | SiC vs antimony-free carbon or SiC / FFKM or Aflas | API Plan 53A or 54 (compatible barrier ≥ 1.4 bar above vessel pressure) |
| Toxic Monomer Feed (VCM / styrene) | Liquefied volatile monomer | Ambient | 12–25 | Dual pressurised cartridge | Carbon vs SiC / FFKM | API Plan 53A (barrier ≥ 1.4 bar / 20 psi above seal-chamber pressure) |
| Stripper Column Bottoms | Polymer slurry / latex, sticky | 85–110°C | −0.8 to +4 | Dual balanced cartridge (vacuum duty) | SiC vs SiC / Aflas or FKM | API Plan 53A (barrier ≥ 1.4 bar above seal-chamber pressure) |
| Rubber Coagulation Agitator | SBR / NBR latex with dilute sulphuric acid | 60–80°C | Ambient to 2.5 | Top-entry agitator seal, alloy wetted parts | Tungsten carbide vs SiC / Aflas | Plan 32-type clean flush or quench, per vessel design |
| Crumb Rubber Slurry Transfer | Crumb rubber in acidic water | 60–80°C | 3.0–5.0 | Heavy slurry single cartridge, springs out of the product (catalogue ref. HS860) | Tungsten carbide vs SiC / Aflas | API Plan 32 (clean water flush) |
Reviewed by Gipfel Engineering’s technical team.
Technical Information Disclaimer
The information on this page, including process descriptions, flow diagrams, operating ranges, seal arrangements, materials and piping plans, is general technical guidance for information only. Values shown are typical industry ranges, not guaranteed ratings or specifications of any Gipfel Engineering product. Each application differs. Seal selection, material compatibility, installation and operation must be verified by qualified personnel against the specific equipment data sheet, process conditions, applicable codes and the pump manufacturer’s instructions. A binding recommendation is given only in a written quotation or technical offer from Gipfel Engineering.
References to standards (such as API 682, ISO 21049, ISO 3069, FDA 21 CFR 177.2600 and NACE MR0175 / ISO 15156) describe common industry practice. They do not mean that any product is certified, qualified or approved to that standard unless this is confirmed in writing for a specific order. Third-party company and product names, including “equivalent to” references, are used for identification only and remain the trademarks of their owners. No affiliation, endorsement or OEM approval is implied.
Compliance with safety, hazardous-area, environmental and statutory requirements at the user’s site remains the responsibility of the plant owner or operator. To the extent permitted by law, Gipfel Engineering accepts no liability for loss or damage arising from reliance on this general information without a confirmed written recommendation. Content may change without notice.