A Lesson In Trommel Throughput

How to Increase Trommel Throughput Without Buying a Bigger Machine

For many operators, increasing production often leads to one question: Do we need a bigger trommel?

While investing in larger equipment can increase capacity, it’s not always the most cost-effective solution. In our experience, many trommel operators are not getting the maximum performance from their existing machine due to a handful of common operational factors.

At CRJ Services, we work with operators across the UK to maximise the performance of screening equipment, including operators who hire or buy Pronar trommels, hire Doppstadt trommels, and invest in Kentek trommel screens. Regardless of the machine manufacturer, the same operational principles apply when it comes to achieving maximum throughput and product quality. Small adjustments can often deliver substantial improvements in throughput, product quality, and operating costs.

Here are five areas that can have a major impact on trommel performance.

1. Optimise Drum Speed

The rotational speed of the trommel drum plays a critical role in how effectively material is screened.

If the drum is rotating too slowly, material may not turn over sufficiently, reducing the chances of fines finding the screen apertures. Conversely, if the drum is running too quickly, material can be carried around the drum by centrifugal force, reducing screening efficiency and increasing carryover.

Finding the optimum drum speed depends on several factors, including:

• Material type
• Moisture content
• Screen aperture size
• Feed volume

Many modern trommels allow operators to adjust drum speed, but these settings are often left unchanged for long periods. Regularly reviewing performance and making adjustments based on material conditions can significantly improve throughput.

Key Tip:

Monitor the material flow through the drum. If material appears to be “riding” the drum rather than tumbling, the speed may need adjusting.

2. Maintain Consistent Feed Rates

One of the most common causes of reduced trommel performance is inconsistent feeding.

When material is loaded in large surges, the screening area becomes overloaded. Material sits on top of itself, reducing the opportunity for fines to reach the screen surface and increasing contamination in the final product.

A consistent feed allows the trommel to utilise its entire screening area more effectively.

Benefits of consistent feeding include:

• Higher throughput
• Improved product quality
• Reduced machine wear
• Lower fuel consumption

Key Tip:

Aim for a steady, controlled feed rather than loading the hopper as quickly as possible. Consistency generally delivers better results than volume.

3. Understand the Impact of Material Moisture

Moisture content can dramatically affect trommel performance.

Wet and sticky materials tend to clump together, making it more difficult for fines to separate. Screen apertures can become blinded, reducing effective screening area and slowing production.

This is particularly common when processing:

• Compost
• Green waste
• Soil
• Biomass materials

During wetter periods, operators may need to adjust their processing strategy to maintain performance.

Possible solutions include:

• Reducing feed rates
• Adjusting drum speed
• Using appropriate cleaning systems
• Changing screen configurations
• Pre-processing material where possible

Key Tip:

If throughput suddenly drops after rainfall, check for screen blockage before assuming there is a mechanical issue.

4. Select the Right Screen Apertures

Screen selection is often overlooked, yet it can be one of the biggest factors influencing trommel performance.

Using apertures that are too small can restrict throughput, while oversized apertures may compromise product quality and increase contamination.

The ideal screen configuration will depend on:

• Material type
• Desired product specification
• Moisture content
• Required throughput

Different materials often require different drum configurations throughout the year.

For example:

• Compost producers may prioritise product quality.
• Biomass operators may focus on throughput.
• Soil processors may require a balance between both.

Key Tip:

Review your screen setup regularly. A screen configuration that worked perfectly six months ago may not be optimal for current material conditions.

5. Improve Loader Operation

We frequently see customers operating both hired Doppstadt trommels and Pronar trommel screens achieve noticeable productivity improvements simply by adjusting loading techniques and maintaining a more consistent feed rate. The operator feeding the trommel can have a surprisingly large impact on performance.

Poor loading practices can create bottlenecks, overload the hopper, and reduce overall screening efficiency.

Common issues include:

• Overfeeding the machine
• Loading unevenly across the hopper
• Introducing oversized material
• Feeding large surges rather than maintaining a steady flow

Well-trained operators understand how the trommel performs and adjust their loading technique accordingly.

Key Tip:

Encourage operators to focus on maintaining a consistent material flow rather than simply keeping the hopper full at all times.

Small Changes Can Deliver Big Results

Increasing trommel throughput doesn’t always require a larger machine.

By focusing on drum speed, feed consistency, moisture management, screen selection, and loading practices, operators can often unlock significant improvements from their existing equipment.

In many cases, the difference between an average-performing trommel and a high-performing trommel comes down to setup, maintenance, and operator technique rather than machine size.

Could Your Operators Be the Key to Higher Throughput?

Even the best trommel will struggle to reach its full potential without the right operating techniques. Factors such as feed consistency, material presentation, machine setup, and daily maintenance all have a significant impact on productivity.

CRJ offers operator training designed to help teams maximise machine performance, improve product quality, reduce wear, and operate more safely. Combined with our expertise in servicing, repairs, and machinery support, we can help you get the very best from your equipment.

To find out more about trommel operator training or machine optimisation, contact the CRJ team today.