Buying a used stainless steel reactor can be an excellent investment โ provided you know what to look for. This checklist, developed from years of trading in used industrial process equipment, will help you make informed decisions.
Documentation: What to Ask For
On the used equipment market, comprehensive original documentation is the exception rather than the rule. Many units that have been in service for decades have lost their technical files โ especially those decommissioned from legacy plants โ yet remain in excellent condition. The absence of documentation is not, by itself, a red flag; it simply means you'll need to compensate with a more thorough physical inspection.
When available, however, ask for: CE declaration of conformity, Pressure Equipment Directive (PED) test certificate, material certificates (EN 10204 3.1 or 3.2), as-built drawings, and maintenance history. Any document you can obtain will make commissioning at the new site significantly easier.
Available Documentation โ Checklist
- CE declaration of conformity (if present)
- PED test certificate (pressure vessels)
- Material certificates (EN 10204 3.1 / 3.2)
- As-built drawings or design data sheet
- Maintenance and inspection history
- Last hydrostatic test date
- Previous operating medium and temperature/pressure
If the reactor will process flammable or potentially explosive substances, or if it will be installed in a classified hazardous zone, it โ or the entire installation โ must comply with ATEX regulations. This requirement applies both to the vessel itself and to all associated equipment (motors, seals, instrumentation). Verify ATEX certification before purchase if this applies to your process.
External Inspection
The exterior of the reactor tells a lot about its history. Start with a general visual survey, then focus on the most critical areas.
External Inspection โ Checklist
- General shell condition: deformations, dents, impacts, cracks
- Weld seams: check for signs of repair welds or discolouration
- Heating/cooling jacket: check for leaks, corrosion, damaged connections
- Nozzles and flanges: condition, gasket faces, flange ratings
- Support legs and base frame: structural integrity
- Insulation (if present): condition, moisture ingress, gaps
- Identify the steel grade (visual markings, nameplate, or XRF test)
"On the jacket, check for signs of scale or deposits from old heating/cooling fluid โ these may indicate the circuit was never properly cleaned or drained."
Pay particular attention to the heating/cooling jacket: leaks here are often repaired in place and may not be visible to the naked eye. If possible, request a simple pressure test on the jacket circuit.
Internal Inspection
The interior of the vessel is where the most critical wear occurs. Always request access for an internal inspection โ if it is refused for no valid reason, treat this as a serious concern.
Internal Inspection โ Checklist
- General surface condition: corrosion, pitting, discolouration, erosion
- Weld seams: cracks, porosity, areas of weld repair
- Bottom head (dished end): signs of chemical stress from concentrated products
- Wall thickness measurement with ultrasonic gauge (key in corrosive service)
- Internal nozzle ends: condition of gasket seats
- Baffles (if present): fixings, deformation, corrosion
- Internal surface finish (Ra): relevant for hygienic or high-purity applications
Ultrasonic thickness measurement is the most important check on a used reactor. Values must be compared with the original design thickness. A residual wall thickness within the standard corrosion allowance (typically 1โ3 mm below nominal) may still be fully acceptable for continued service โ always compare with the design specifications.
Agitator and Seals
The agitator assembly is often the highest-wear component of a reactor. Assess it carefully.
Agitator and Seals โ Checklist
- Impeller condition: deformation, erosion, corrosion, missing blades
- Shaft straightness: a bent shaft is often not worth repairing
- Shaft runout: acceptable tolerance is a few millimetres on long shafts
- Gearbox/drive: oil leaks, unusual noise, gear wear
- Mechanical seal or stuffing box: condition, leakage, ease of replacement
- Coupling between motor and gearbox: condition, alignment
Mechanical seals have a finite service life and will likely need replacement. Factor this into the purchase price. For double mechanical seals or packed stuffing boxes, check whether spare parts are still available for the specific brand and model. Well-known brands (Burgmann, John Crane, Flowserve, Roten) generally have good parts availability.
The drive motor brand is secondary: any standard three-phase motor can be replaced independently if needed. What matters is the gearbox ratio and output speed in relation to your process requirements.
Key Questions to Ask the Seller
Beyond the physical inspection, the information the seller can provide is invaluable. Here are the most important questions:
Questions for the Seller
- What was the last product processed? At what temperature and pressure?
- Why is the equipment being decommissioned?
- What maintenance was performed in the last 3โ5 years?
- Were there any significant incidents or repairs?
- How long has the reactor been idle?
- Is the reactor available for a hydraulic test?
- Is it possible to inspect the equipment running (if still connected)?
"A seller who answers honestly โ including about defects โ is a far better counterparty than one who only tells you what you want to hear."
Logistics and Transport
Once you have decided to purchase, transport is the next major challenge โ especially for large vessels.
Pre-Transport Checklist
- Measure overall dimensions including all nozzles, legs, and agitator assembly
- Check the dismantling sequence (agitator, insulation, external piping)
- Verify whether special transport permits are required (oversized loads)
- Protect all flange faces with gaskets or plastic covers
- Secure the agitator shaft to prevent rotation and bearing damage in transit
- Consider internal cleaning before transport (especially after hazardous products)
During transport, the agitator shaft must be properly braced and locked. Movement of the shaft can damage mechanical seals and bearings โ components that are expensive to replace. Use wooden wedges or purpose-made transport brackets.
The Coprinox Approach: Transparency Over Cosmetics
At Coprinox, we sell used process equipment as-is, without refurbishment. This means you see the equipment exactly as it was at its last operating site โ no paint touch-ups, no polishing to hide wear, no concealed defects.
We believe this is the only honest approach for a professional buyer. Our role is to provide all available information and grant full access for inspection. The assessment of suitability for your specific application remains your responsibility โ and that of your technical team.
"We don't refurbish because we believe professional buyers deserve to see reality, not a cosmetically improved version of it."