Vacuum oiling line

Vacuum coating system: a nutritional enrichment for pellet and extruded feeds.

The vacuum oiling lines for cold extruded feeds are used to enhance the nutritional characteristic adding oil and other additives.

These lines are applied in the field of extruded feeds for:

  • Fish farming
  • Pets


The vacuum mixer was conceived to integrate liquid ingredients (i.e., oil and melt fat) directly in the extruded product as soon as it has gone through the drying process. The liquid absorption is guaranteed on a product with diameter ranging from 2 to 18 mm. with maximum humidity up to 8%.
The percentages of liquid ingredients that can be added to the product range from 8 to 20% and the top amount of achievable vacuum is -20mBar.

Dried product

Air evacuation


Liquid absorption

Final product





The line is made up of:

One or two mixers ( dipending on productive capacity reqiuired ) with rotating shaft and adjustable adjustable blades installed on load cells and butterfly valves to vacuum seal both incoming and outgoing.
Each mixer is equipped with a spraying line composed each by a series of nozzles of oil or fat.The mixer can be easily inspected through two doors . The engine power of each mixer is 18.5 kW The Vacuum line comprises a lobe pump with 11 kW motor The line further comprises one or more dosage units of the liquid in which each of two containers in series constructed of AISI 304 steel .
the first container is mounted on load cells for weighing the liquid to be sprayed .
The process is automated with a control panel equipped with a video touch screen


Liquid addition process

Load hopper #1 till it reaches the pre-set weight; once this weight is reached, the bypass deviates towards hopper #2. The first batch of product is discharged in the mixer by the opening of the hopper’s shutter; at the same time, the mixer’s valve is opened. Once the pre-set weight is reached (and detected by the load binb on the mixer) the shutter closes and immediately afterwards the mixer’s valve shuts as well. The amount of liquid to be sprayed is weighed and then the liquid is injected in the mixer. The “vacuum pump” creates the vacuum in the mixer up to the pre-set level. The vacuum is detected by a pressure transducer.Then the product is mixed for the pre-set time; after that, the air pressure is restored by the opening of valves .At the end of the process, the discharge door and the discharge valve open up; now the mixer is ready for a second batch. The length of the process depends on the settings: it may vary from 6 to 10 minutes.The weight of the batch may vary from 300 to 1500 Kg.
Optional units: Electrical cycle control panel with PLC options of humanmachine interface and program processed by our company.