Servicing AD Sites Across the UK

AD Digester & Stirrer Parts & Repair

Reliable mechanical mixing is fundamental to anaerobic digester performance, directly influencing solids suspension, temperature uniformity, biological stability, and overall biogas yield. At Fletch Engineering Services, we specialise in the repair, manufacture and refurbishment of digester and stirrer components for AD plants across the UK.

Fast response guaranteed

Specialist Engineering & Component Supply for AD Plants

Anaerobic digesters present a uniquely demanding operating environment combining abrasive feedstocks, high torque transmission, cyclic loading, and exposure to corrosive gases including hydrogen sulphide.

When components wear or fail, it can reduce efficiency, increase maintenance demands, and lead to unplanned downtime. Our team is on hand to restore performance quickly and keep your systems running efficiently.

We manufacture replacement and OEM-equivalent components, including:

Main drive shafts and extension shafts

Mixing blades, paddles, and impellers

Bearing housings and support assemblies

Custom-machined and fabricated assemblies

Whether replicating existing parts or improving designs for increased longevity, all components are manufactured to precise tolerances using materials suited to demanding operating environments.

Supporting Continuous Operation

We understand that digester and stirrer performance is critical to overall plant output. From one-off emergency repairs to ongoing support, our team works efficiently to minimise downtime and maintain operational continuity.

Precision. Reliability. Performance.

Our Promise

By delivering dependable repair, refurbishment, and replacement solutions, we help ensure consistent performance and long-term reliability across your AD plant. Every component is assessed against original specifications and, where beneficial, we implement design improvements to address known wear points or operational weaknesses.

Designed for Performance & Longevity

Our engineering approach focuses on:

Maintaining mechanical integrity and fatigue resistance

Minimising vibration through precise concentricity and balance

Extending component lifespan in high-wear, corrosive environments

Supporting long-term dimensional stability in continuous use

All components are inspected for quality and fit, ensuring reliable integration into existing equipment.

What our clients say

Fletch Engineering turned around a critical shaft repair in days. Quality was perfect and fitted as needed. Kept our AD plant running with minimal disruption. Highly reliable team.

We required precision parts and needed them delivered fast. Everything matched OEM spec exactly. Have to say, solid workmanship and the Fletch team are very easy to deal with. They are now our go-to service providers.

Professional and knowledgeable team who managed to produce custom parts from old components with no drawings. Highly impressed with both the fit and finish, excellent company to deal with!

Built Around Speed and Reliability

Quick Turnarounds

We focus on rapid turnaround for both manufactured components and repair work. Our workshop facilities allow for detailed inspection and structured refurbishment, helping to minimise disruption and return your plant to full operation as quickly as possible.

Extensive Knowledge Across Our Team

Our team has extensive hands-on experience supporting AD plant operators across the UK. We understand the operational challenges your equipment faces every day, from abrasive feedstocks and corrosive digestate to the pressures of continuous 24/7 processing.

Solutions Focused

Every plant and every component presents its own challenges. Where a straightforward replacement is required, we deliver it efficiently. Where a component has failed due to a design or material weakness, we assess the cause and manufacture the replacement to an improved specification, reducing the likelihood of recurrence.

Complete our enquiry form and our team will be in touch

Frequently asked questions

What processes are involved in digester stirrer repair?

Our repair process typically includes shaft straightening and run-out correction, structural weld repair, blade rebuilds and reinforcement, bearing seat and journal restoration, and replacement of worn wear strips and protective elements. Each component is assessed against original specifications before work begins.

How are replacement components manufactured?

All components are produced to precise tolerances using appropriate grades of carbon steel, alloy steel, or stainless steel depending on application requirements. Where required, we incorporate full penetration weld procedures, hardening, dynamic balancing of rotating assemblies, hard-facing and wear-resistant coatings, and journal surface machining.