Troubleshooting

Shear parameters is a topic with great potential depth. No doubt can affect the product with an example of a basic formula being over sheared where the mallard reaction has occurred which might change palatability for some pets. This is where the flexibility in the process might be an area of review.

The possibility exists to make a very wide range of products on the same extruder set up but are sacrifices being made? Capacity mainly as easily cooked formulas usually can be produced at maximum rates. These extruders would have a barrel designed to move material forward, a restriction zone about ¾ of the way through with a straight rib head and double flight screw. With shearlock diameter adjustments, variable speed main drive and an adjustable flow control restriction right behind the die you have the basis of many production machines. These would be able to produce many of the 12 to 15 percent fat level products and lower. Depending on meat moisture levels some can be added and handled. When you push the meat levels then a more aggressive, disruptive, barrel design is needed both twin and single screw designs. Lobe locks installed to totally or partially pump or push backwards, cut flight screws of various designs and combinations thereof all designed to increase cook are available. Twin screws have an advantage from the start with their more positive pumping designs regarding fat and meat additions. Due to the interacting screws rotating in unison and usually a longer L/D, length/diameter, increased flow restriction sites can be set up. This would allow elevated meat and fat additions. It is not easy to do if you are doing this screw barrel design while trying to keep capacity at a maximum with flexibility. Restricting the flexibility to a range makes it easier to achieve with repeatability. Frictional cook or cooking with shear has limits when meat inclusion elevates past reviewed technology. Thermal cooking systems exist to go to the next level by extrusion with elevated steam injection or thermal plate heat exchanger style technology. With planning of schedule to reduce numbers of extruder barrel changes you greatly reduce downtime over the year while covering a wide range of products. These elevated meat and fat and other exotic formulas are greatly enhanced by system computer control for correctness and maximum productivity. Keeping extruder wear data slaved to the operational records exacting information for running conditions can be predicted and controlled over a time period.

Previously on Troubleshooting...

1. Density

An examination of product density and its relationship with moisture levels, heating, cooling feeder screw rate and automation.

2. Non-uniform and rough appearance

A guide to understanding the science involved in improving the art of making products of all the same size.

3. Extrusion dies

This article takes a look at aspects of the process including high, medium and low shear as well the adjustments required when producing feed for small mammals.

4. Dryers

The dryer is without a doubt one of the machines in the system which greatly impacts the bottom line.

5. The Extruder Barrel - Part 1

Forming extruders are used for some select products – thus this part of the discussion centres on single and twin designs.

6. Cook in the Extruder Barrel – part 2

As discussed last month, the extruder barrel has a number of functions, but the main goal is to finalise the cook, yield the desired shape with the density target.

7. Coating

The coating process has a few areas of importance, with this edition of ‘Troubleshooting’ exploring the most important of these.

8. Expanded cat food

Dry expanded cat food production is similar to dog food production, but there are some differences, with this edition exploring a choice selection of these.

9. Extrusion during operation

This month we discuss steam input into the conditioner. During the water addition process, the steam is usually in the two-bar range.

Innovations this month

March 2023

This month’s Production Showcase section features equipment and ingredients that will help in the production of petfood, taking you right from the recipe book, right up until until your product is ready to leave your factory door.

If you would like your product or service to appear on this page in a future edition of International Petfood magazine, then please contact us at editorial@perendale.co.uk

Continuous Coaters by Ottevanger

The Ottevanger Continuous Coaters are perfectly suitable for adding and mixing liquids, evenly on pellets and/or extrudates. By dosing the liquids through a spray box, the product and liquids are slowly mixed together. The trough of the coater itself is executed in stainless or mild steel, with 50 mm thick insulated jacket. The heat tracing stimulates the absorption of the liquid and avoids contamination of the trough. The coater is equipped with hinged inspection hatches over the full length of the mixing trough, which allows easy access. Apart from oil and/or fat, also vitamins, enzymes etcetera can be added in small quantities. Dosing systems for these products are available upon request.

It has numerous features including Low power consumption, large doors enabling easy inspection/cleaning, rigid construction and variable heating system with insulated jacket and also has a low rate of wear. https://www.ottevanger.com/en/products/coating/continuouscoaters/