The expander is a machine that has the function of improving the quality of pellets while making it easier to process. Combines temperature and pressure in the raw material passage phase to give the mixture the best nutritional value. La Meccanica expanders are very versatile machines that increase the gelatinization of starches and improve the granulation of even the most difficult raw materials.

  • — Expander is an extruder-like device that combines temperature and pressure to process raw materials and produce a pulverized product with improved nutritional value compared to traditional feed.

    — The expander is equipped with:

    • • power transmission
    • • loading hopper
    • • independent drive section with adjustable flat die
    • • multi-cutting mechanism with variable speed of knives that grind the material into a homogeneous crumb

    — The main drive has a hydraulic connection with built-in overload and V-belt transmission;

    - Powerful pressing auger is made of several sections on one shaft, increasing cutting;

    - The die device can be hydraulically disconnected from the machine for easy access;

    - The opening of the die is hydraulically controlled and allows the operator to increase or decrease the compression / cutting and extrusion / shaping of the final product at a distance;

    — adjustable blade speed with an independent drive to determine the size of the crumb and ensure a uniform product size;

    — With the help of the expander length, it is possible to increase the flow under high pressure. This is possible thanks to many special nozzles.

    - Numerous injector places allow you to increase the flow pressure and add additional liquids along the entire length of the expander;

    — automatic control allows the operator to set parameters and the system can be configured according to them;

    - flexibility due to the number of injection points and short start-up times allow the system to stop and start without problems;


Expander type total length screw diameter screw speed shaft length productivity t/h transmission kW
STHT 230 4120 230 300 1300 5-12 110-132
STHT 305 6700 305 230 1500 12-20 160-200
STHT 305 compact 3900 305 230 850 12-20 160-200
STHT 350 7405 350 209 2376 24-30 250-315


The rollers are adjusted by a hydraulic piston driven by a hydraulic device located outside the machine and controlled from the control panel.

The position of the rollers is calculated by means of an angular potentiometer mounted behind the rollers (inside the main shaft). The potentiometer signals the angular position of the roller pins. By operating the entire system from the control panel, the distance between the rollers and the die can be calculated using the signal transmitted by the potentiometer.

At the electronic panel, the operator chooses the roller position. The panel pressurizes the hydraulic circuit and moves the piston until the rollers reach the desired position.

From the electrical panel, the operator determines the position of the rollers by applying pressure to the hydraulic system and moving the piston until the rollers reach the desired position. Once the desired position has been reached, the system is locked and held in position by two valves.

The maximum pressure reached by the hydraulic system is 250 bar, and the required pressure for moving the piston and adjusting the rollers is 150 bar.

The adjustment is done quite quickly: you can move the rollers closer or further away from the matrix by 7-8 mm, in each direction in about 15 seconds.

For more information, watch the following video: Automatic Rollers Adjustment (WAP System)

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The device allows replacing the matrix in 10-20 minutes, depending on its size. The system includes a tapered stainless steel ring that is closed and held in place by Belleville disc springs.

This ring locks the die in place. The matrix is released by pressure on the hydraulic system, which pushes the springs to release the elastic ring.

For more information, watch the following video: Rapid Block System

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The system consists of a hand pump and a piston, which are needed to dismantle the die.

The piston is installed between the rotor and the reinforcement flange so as to push the die out of its seat.


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This system includes a high viscosity grease pump.

It is equipped with blades to break up possible air bubbles. The system is connected to the press via a rotary distributor connected directly to the main shaft.

Lubrication is controlled by an electrical panel that is included in the delivery. The panel allows you to measure the required amount of grease using two timers to regulate the time for applying grease and pause.


The pump has the following characteristics:

● the flow is adjustable from 2.9 to 17 cc / min.

● motor 0.185 kW, 400V, 50Hz

● steel tank for 10 kg

● filter

● pressure relief valve

● pressure gauge

● indicator of minimum lubricant level

● progressive dispenser for distributing grease at two points

● inductive PNP sensor for cycle monitoring

● control valves for 1/8 outlet