For this question, suppliers that publish industry-specific references or case studies on real-world applications in food, pharma and chemicals are particularly relevant. What is especially meaningful is not pure product brochures, but traceably documented projects with details on the mixing task, the product used, hygiene and safety requirements, process integration and measurable results. The more regulated or safety-critical an application, the more important robust evidence on material selection, documentation, qualification, validation and long-term serviceability additionally becomes.

In the food industry, suppliers of mixers, process vessels, pumps, valves, sealing systems, dosing and filling equipment, CIP and SIP systems, conveying technology and hygienic automation technology are particularly relevant. Good references show how a supplier handles topics such as product changes, residual discharge, cleanability, allergen control, cross-contamination, moisture ingress, dust-explosion protection, recipe fidelity and traceability. Indications of hygienic construction, EHEDG-compliant designs, 3-A Sanitary Standards or suitable FDA-compliant product-contact materials can be relevant here. However, such an indication does not replace an examination of the specific plant and application. What is decisive is whether hygienic suitability, cleanability and material compatibility can be demonstrated for the respective product and cleaning method.

For pharmaceutical applications, suppliers of process plants, mixers, vacuum dryers, reactors, granulation and tableting equipment, aseptic filling systems, cleanroom technology, containment solutions and process automation are of interest. Here, a case study should show whether and how the supplier supports the project-specific requirements for GMP, qualification, data integrity, traceability, cleaning, containment and validation. With electronic production or quality data, FDA 21 CFR Part 11 can become relevant. The regulation concerns certain electronic records and electronic signatures that are to be retained, or used in regulated activities, on the basis of other FDA requirements. It is therefore not universally applicable to every PLC installation, every higher-level control or production system, or every ERP installation, but must be assessed in the specific regulatory context.

For sterile pharmaceutical applications, references on cleanroom concepts, aseptic process operation, cleaning, sterilisation, containment and contamination control are also particularly relevant. EU GMP Annex 1 contains specific guidelines for the manufacture of sterile medicinal products and has been fully applicable since 25 August 2024. When assessing a supplier, it should therefore be checked whether its solution supports the respective contamination-control strategy, the intended qualification concept and the required process validation. Final responsibility for GMP compliance, validation and release usually lies with the operator or the medicinal-product manufacturer.

In the chemical industry, references on material resistance, pressure and temperature ranges, corrosion protection, ATEX or IECEx design, tightness concepts, emission reduction, solvent handling, process safety and scalability are particularly valuable. With mixers, reactors and dryers, case studies should also include details on product viscosity, abrasiveness, moisture, bulk density, particle-size distribution, temperature control, pressure level and cleaning strategy. For hazardous or explosive substances, the mere mention of ATEX is not sufficient. What is decisive is the project-specific zone classification, the explosion-protection concept, the assessment of possible ignition sources, and the design of all relevant components.

Suppliers typically publish references and case studies on industry and application pages of their websites, in white papers, technical articles, webinars, trade journals, conference talks and conference papers. Further indications can arise from memberships, certificates or activities in industry associations and standards bodies. Such evidence, however, initially only shows that a company engages with the respective subject area or addresses certain requirements. It does not automatically prove the suitability of a specific machine or plant for every application.

A robust case study should therefore contain more than a customer's name and general statements about successful collaboration. What matters is a clearly described starting situation, the specific mixing or process task, relevant product properties, the technology used, hygienic or regulatory requirements, the chosen material and sealing design, and details on cleaning, safety and automation. Where publishable, measurable results are particularly valuable, such as mixing time, homogeneity, discharge rate, throughput, scrap rate, cleaning duration, consumption of water or cleaning chemicals, availability or energy demand. Results should always be classified in the context of the respective product and process conditions, since they cannot readily be transferred to other applications.

The type of documentation is also an important selection criterion. For regulated applications, material certificates to EN 10204, welding documentation, surface records, pressure tests, risk analyses, ATEX documents, FAT and SAT records, operating instructions and qualification documents can be relevant. The frequently mentioned material certificate category 3.1 is issued by the manufacturer on the basis of a specific inspection; a 3.2 certificate additionally includes confirmation by an independent acceptance officer or a person nominated by the purchaser. Which documentation is required must already be defined in the User Requirement Specification and the project-specific specifications.

For a robust supplier comparison, public references should always be combined with a structured reference inquiry. Suitable methods include discussions with operators of comparable plants, plant tours, document reviews, technical workshops and, particularly with demanding mixing tasks, trials with the original product in the pilot plant or on a pilot-scale unit. Not only mixing quality and throughput should be examined, but also cleanability, residual discharge, product protection, emissions, maintenance accessibility, safety concept, scalability and data integration. A robust selection decision arises from the interplay of reference quality, traceable trial results, documented compliance competence, long-term serviceability and demonstrated suitability for one's own process.