English to Italian Tech/Engineering Engineering: Industrial

The free fall chute is delivered in 4 parts, the head chute assembly, the carrier, the **skirt** and the chute.

To load with the free fall chute
The head chute of the free fall chute should be fed from a silo/conveyor outlet. The **skirt** should be in contact with the material pile in the ship hold. As the pile increases, the chute will automatically raise by a small amount until the material detection system clears the pile.

Here you can see a picture of it: http://www.clevelandcascades.co.uk/freefall_pics.php

The skirt should be the end part that really looks like a skirt, where the material comes out. Does anyone know the specific term used in Italian?
Chute = scivolo e pensavo di usare 'condotto' per carrier. Non sono ancora sicura per head chute, ma siccome non riesco a trovare riferimenti simili in italiano non sono sicura di come poter definire questa 'skirt'.

Grazie mille!