GOOD VIBRATION
The MVT et MVTX series are designed for one precise use : driving a screen. They are the most powerful machines in the foot-mounted catalogue, up to 77.8 kN, with a three-part frame and a typically horizontal mounting.
The whole family runs in 4 poles at 1,500 rpm. The choice is therefore not about speed, but about force and about whether an ATEX certification is needed.
At equivalent reference, both versions deliver exactly the same force, on the same frame size and for the same weight. The difference lies entirely in the enclosure and in the certification, not in the performance.
| MVT | MVTX | |
|---|---|---|
| Use | Industrial screening outside classified areas | Screening in potentially explosive atmospheres |
| Certification | None | ATEX II 2 G Ex d IIB 105 °C Gb II 2 D Ex tb IIIC T105 °C Db IECEx, cULus, EAC |
| Permitted zones | — | 1, 2, 21 et 22 |
| Terminal box | Large fixed connections | Thickened cover, sealing by flameproof gasket |
| Thermal protection | On request | Bimetallic 130 °C as standard |
| Mechanical performance | 33.8 to 77.8 kN | Identical — 33.8 to 77.8 kN |
| References | 4 | 4 |
The MVTX is characterised by increased thickness and gaskets intended to prevent an explosion arising inside the machine from spreading to the surroundings. The certificates are DEMKO 12 ATEX 1103487X et IECEx UL 11.0043X, supplemented by the cULus E129825 approval (Class I Groups CD, Class II Groups EFG, class T4 at 135 °C) and EAC certification.
A screen is not sized like a hopper. On a hopper, the aim is to release material from a wall. On a screen, a permanent movement of a whole box is maintained, with an amplitude that directly governs separation efficiency : too low, and the product does not stratify and the mesh blinds ; too high, and the product bounces instead of advancing and grains pass over the mesh without meeting it.
It is the only criterion that cannot be put right afterwards. If the screen is installed in a classified gas or dust area, the MVTX is required, and the choice is then made within the four certified references. Outside classified areas, the MVT gives the same performance without the additional cost of certification.
Centrifugal force describes what the machine pushes ; it is the static moment that decides the amplitude obtained on a given box. The Italvibras catalogue defines the working moment as twice the static moment. On this family it ranges from 1,369 to 3,147 kgmm — a ratio of more than two between the smallest and the largest reference, at the same speed.
In practice, two screens of the same mass fitted with the 15/3500 and the 15/7900 will not simply behave 'more or less strongly' : they will work at different amplitudes, and therefore with different particle-size cuts. Sizing starts from the total mass set in vibration and from the amplitude targeted — that is the point on which we support you.
The eccentric weights are adjusted continuously, as a percentage of maximum, with hand tools. That is precisely what allows the screen's behaviour to be refined once the installation is in service, when the actual product turns out to differ from the specification. Choosing a reference slightly above the calculated need and turning it down is always more comfortable than being stuck at 100 %.
These machines weigh from 169 to 285 kg and measure from 1.13 to 1.48 m long. The bearing flange is designed to transmit the load evenly to the frame, but it is indeed the screen structure that takes the force. Mounting is typically horizontal, and the overall size must be checked before choosing the frame : moving from the 15/5000 to the 15/7900 adds nearly 35 cm of overall width.
Note : the Italvibras catalogue does not publish the electrical data of the MVT 15/7900-S08 — power, current and starting ratio do not appear there. We obtain them from Italvibras on request ; we prefer to show nothing rather than an approximate value.
Give us the mass of the box, the amplitude targeted and the zone classification : we will point you to the right reference and pass on the data the catalogue does not publish.
Request a quoteData from the Italvibras general catalogue 2019, pages 62 to 65. Audimat Automation, official Italvibras distributor.
Neighbouring families and useful resources to refine your choice.