Hotter, bigger, better

by Emily Wilson
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Revolutionary advances in feed technology don’t come around that often, but when they do, they tend to debut at Victam. At the Victam Europe show in the Netherlands this past November, there were some introductions but no real surprises. There were certainly some interesting modifications to existing models and a tendency for manufacturers to link machines together to come up with new processes or applications.

The emphasis was on meeting the new standards of hygiene, traceability and minimum environmental impact required in feed processing as a link in the food chain, with most innovations being in process control and feed safety, in particular in heat treatments.

There was also a trend toward larger capacity machines.

The growing interest in aquatic feeds was evident in the number of machines aimed at this market, particularly vacuum coaters but also fine-grinding hammermills and extrusion systems.


Higher capacity was the notable influence on Sprout Matador’s new equipment line. The company has launched a new generation of gear-driven pellet mills, with capacities up to a massive 100 tph, making its claim to be the highest capacity of any pellet mill in the world hard to dispute. The company has also launched a vacuum coater with an effective batch size of up to 3,000 liters and a high-capacity hammer mill for fine grinding.

The new Sprout Matador EX1250 extruder was designed with the fish and pet food industries in mind and offers capacity of 15 to 20 tph. It is fully automated with a new PLC-based process system for control of loss-in-weight system, feed screw, conditioner, extruder, knife, expansion control unit and additives, as well as steam addition in the conditioner and extruder.

Optional features include links between plant PLC, dryer and coater, ensuring traceability. The extruder also has the option of using the new ECS (expansion control system). This innovative tool controls product expansion and density by controlling the die plate exit pressure.

Falling into both the "heat treatment" and the "bigger" categories is Extru-Tech’s Maxxim series extrusion systems, which are so new that the company didn’t even have a model available at the show. The new line of enhanced single screw cooking extruders provide dramatically increased throughput and higher operational speeds, which with a larger drive motor makes this range capable of 20% to 30% production rate increases over previous models with the same barrel diameter.

Extru-Tech’s inline drive system has been re-engineered to handle up to 600 hp compared with 350 hp on previous models. In addition, many ongoing improvements have been made to the barrel design, including changes to the screw profiles and the ribbing design in the sleeves.

Other improvements include a screw support assembly that eliminates metal-to-metal wear. This assembly also allows for thermal expansion, which occurs as the screws are heated up to operating temperature. Other features include improved die design and replaceable die faces for lower operational costs.

Wenger has made a major departure from its focus on single-screw technology with the introduction of the C2TX. This new machine is a conical, co-rotating twin-screw extruder that generates compression continuously throughout the barrel.

The intermeshing co-rotating conical screws have a unique profile, which knead the recipe as the product moves through the extruder barrel. This screw/barrel profile, on which patents are pending, eliminates the requirement of expensive, multiple, and complex extruder screw and barrel components that in conventional twin screw extruders will typically include reverse flight or cut flight screws, multiple shear lock zones and extended L/D configurations for achieving the desired product characteristics.

The C2TX produces the complete range of extruded products including petfoods, aquatic feeds, and foods for human consumption. Finished product characteristics are easily controlled by adjusting product temperature and moisture of raw ingredients, adjusting screw speed (500 to 1200 rpm) to increase or decrease shear rate, and by increasing or decreasing extrusion pressure in a range of 7 to 140 bar (100 to 2000 psi), through an adjustable back-pressure/by-pass valve and die. Finished product density prior to coating may be controlled from 32 to 500 g/l (2 to 32 lb/cu. ft.). Extrusion moisture levels of 10% to 40% are readily achieved with this extruder.

The extruder is available in three sizes from 300 to 1200 kW, with a screw free-volume of 8.1 to 32.4 liters. The smallest C2TX extruder has an effective capacity range of 1,000 to 8,000 kg/hr; the largest, 4,000 to 32,000 kg/hr.

Amandus Kahl’s latest offering is its Eco-processor. A configuration of existing equipment, with some modification to a conditioner, provides ecolological benefits in terms of energy saving and emission control.

In this system, product is preconditioned by adding steam, water, and other liquids in the Eco-processor. The feed is then exposed to hydrothermal pressure treatment by means of an annular gap expander.

Unlike in pelleting, when expandate is produced by means of conditioning with steam using an annular gap expander, flash evaporation takes place. The hot vapors from the expander outlet and the front area of the cooler are collected and blown into the eco-processor in which the feed was preconditioned. Thus, the feed is preheated and moistened by the waste heat from the process resulting in a reduced requirement for more steam.

The CO2 emission is also reduced, as less oil is required for the generation of steam. At the same time, odorous substances contained in the exhaust air are absorbed. Due to the partial recycling of the cooler exhaust air, there is also a reduction of the dust loading.

Using the process waste heat (vapors) from the expander and the inlet area of the cooler for the conditioning of the feed in the eco-processor prior to the expander, the product temperature is increased from 20°C to 40°C (*t 20°C) without addition of steam. This temperature increase normally requires 2% (20 kg/t feed) of steam. In other words, about 1.2 kg of fuel oil/t feed is saved, which would be necessary to generate this steam quantity.

Correspondingly, the CO2 and SO2 emissions are reduced. Compared to pelleting, the expansion requires approximately 5 kWh/t less electrical energy. This means a reduction of emissions in the power plant. The reduced emission of odors is especially important where plants are situated in close proximity to residential areas.

The company claims the system offers 50% heat recovery, 80% reduction of odor emissions, and halves both CO2 and dust emissions.

The star of Buhler’s new product launch is a batch system for the thermal sanitization of feed meal. The system makes full use of recirculated air.

Mash accounts for a full 50% of European feed production and thermal treatments are well established. What Buhler has done is take what has been a continuous process and develop a three-step batch system, which it claims is qualitatively superior as it strictly respects "first in-first out" principles.

The process, with outputs ranging from five to 30 tonnes per hour, can be divided into three stages: sanitization, cooling or drying/cooling and homogenization, as well as mixing with liquid or dry, heat-sensitive additives.

In the first stage, the feed meal is heated with steam in a hydrothermal mixer and sanitized to a level determined by the temperature, moisture and short dwell time. In this operation, the salmonella and other pathogenic germs are destroyed. Due to the effects of the steam, the product moisture increases to 15% to 17%, which helps destroy pathogens such as salmonella and mycotoxins.

Condensation-free and low-residue cooling and/or drying using micro-filtered process air take place in the second stage. This ensures high sanitation and prevents recontamination of the sanitized meal.

An optimal removal of heat takes place on the fluid bed where the process air fluidizes the product and the large surface area of the meal reduces the cooling time to less than half the time that would be necessary for pellets. This optimal removal of heat means a great deal of moisture is removed through the process air. Corresponding air quantities and temperatures prevent condensation that would otherwise cause microbial germination in the cooling system.

In the final stage, the entire product batch is homogeneously mixed and precisely measured heat sensitive dry or liquid additives may be added.

According to Buhler, the advantages of the batch system are the integrated cleaning and sterilization cycles that make it possible to process different formulations one immediately after the other and outstanding flow characteristics that significantly reduce dust and improve water solubility.

These characteristics ensure that automatic feeding systems will function smoothly and that they will be emptied more completely. The same holds true, for example, for discharge of the products from feed bins.

Forberg’s heat treatment system is a two-stage process that utilizes the company’s core competence in mixing technology. It comprises a conditioner/mixer and a dryer/cooler/mixer.

In the first step, the conditioner/mixer is charged with a single ingredient or multiple ingredients that are first mixed with Forberg’s high-speed mixing process. Steam is then injected and the product maintained at the appropriate moisture level, temperature and dwell time to destroy pathogens. Non-sterile liquids, such as molasses may also be added for treatment here.

The conditioner/ mixer discharges directly into the dryer/cooler/mixer and can immediately begin to process the next batch. In the dryer/cooler/mixer, warm and then ambient air is introduced until the product achieves the desired temperature and moisture content. Heat labile liquid or dry additives can then be mixed in.

Process air is either filtered prior to discharge or recirculated in a closed-loop system after cooling. Capacities available for the Forberg Heat Treatment System range from 2 to 60 tph.

With aquafeed in mind, Forberg has also updated its vacuum coater. This third generation machine based on the Forberg mixing principle is equipped with one combined charge and discharge valve on top of the machine and without any bottom doors. This modification solves the leakage problem that has been apparent in a number of vacuum coaters.

Products are charged through the butterfly valve, the valve is then closed and the air evacuated. Liquids can then be sprayed under vacuum and the pressure equalized so that the liquid is drawn into the product. The machine is rotated 180 degrees for discharge through the butterfly valve. Typical cycle time is 3 to 5 minutes. Capacities are available from 2.5 to 7,000 liters.


The ability to control, track, document and reproduce the processing parameters throughout the feed manufacturing process has never been greater. Not only does it create greater efficiency but provides the security and documentation required for the full traceability now required from the feed industry.

Format International launched three new products that will greatly assist in product quality control. Notable is its multi-level optimization package that formulates multiple sub-components both within products and when they are shared across products.

Today’s advanced recipes may contain many sub-components or kibbles, each of which carry its own specification in terms of "claims" and other characteristics. The attributes of the complete product are also defined in terms of nutrition, moisture, ingredients and many other parameters. The challenge is to specify and to optimize the whole product simultaneously with all its sub-components.

Format’s Integra-Mix is designed to optimize products containing other recipes as sub-components. The product, which won the show’s Innovation Award in the "Nutrition" category, optimizes the sub-component recipe based on its inclusion in one or more final products and provides recipe management utilities for multi-level products.

The software facilitates the design and construction of the master product and its hierarchy of sub-components.  It provides easy-to-use tools that display the component levels and allow the recipe designer to fine-tune constraints and attributes at any level of the product.

Format also launched Bio-Security, a software package that performs quality assurance checks on formulae prior to their implementation for manufacturing. It reports on formulae that fail one or more security checks, according to user-defined rules and tolerances.

Bio-Security also assesses the variability of feed recipes and analyzes the risks that feeds will fall outside permitted tolerances and traps unusual or unacceptable constraint costs, reports them as exceptions and ensures that critical or essential ingredients are present and that prohibited ones are absent.

To meet the requirements of full traceability of formulation data, the company has developed the Tracer module, which will store the complete set of data used to create any given formula. As well as the actual formulae, their corresponding specifications and the raw materials used, associated data such as product labels/tags and Bio-Security templates may also be stored.

Van Aarsen launched three new process control systems at Victam: Press Manager, for control of either a single pellet mill or a complete pelleting line; Mill Manager, for complete mill or processing line control; and Moisture Manager, for monitoring the moisture content of the product throughout the process.

Press Manager controls either single or multiple complete pelleting lines or a single press, and can work with any brand of equipment. The PC-based system can operate fully automatically or manually.

In manual mode, each machine can be started up individually by pop-up window. Process parameters can be tracked and recipe data include meal bin selection, pellet mill load, meal density and crumbler/sieve selection. Non-standard options available include hydraulic roller adjustment, fat-spray at the die, automatic lubrication control, conditioning and liquid addition systems, day program recipes and moisture control

Press Manager can be integrated into the company’s new overall mill control program, Mill Manager, an open configuration PC-based system with full color graphics showing accurate and up-to-date plant flows. The program is fully modular and divided into sections for intake, dosing, grinding/mixing, Press Manager and bulk/finished storage.

Van Aarsen also launched a microwave-based moisture measurement device. Different types of sensors are available for different applications such as raw material intake, in the mixer, in the pelleting process or in bulk outloading. The company claims that optimizing the moisture within the process increases profitability by 3%.

Norvidan also launched a PLC-based complete plant control system, which is an example of grouping together existing products. The NPCS incorporates Norvidan’s on-line system for pellet quality testing that allows real time adjustment to pellet quality while documenting quality during production, their established TOPS system for optimization and documentation of the pelletting process and NIMS continuous moisture content measurement system. This system measures moisture in raw material, ground and pelleted products throughout the production process.            WG