I think the notion of 'along' is unnecessary here, inasmuch as we are talking about a device that is inherently linear in nature. What IS important, however, is WHERE these agitators are located: i.e. at a place where the auger has no flights.

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Note added at 20 heures (2016-10-30 08:22:59 GMT)
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If by the use of 'along' (i.e. 'lengthwise') the source text was seeking to emphasize the axial (rather than radial) positioning of the agitators, then one could equally well say '... disposés dans le sens longitudinal...' or other equivalent wording to highlight that intention.

My point really is that I don't think 'along' here has the sense of 'all down the length of'.

English term (edited): are provided along ...

A similar phrase is contained in the following patent:

12. A separator according to claim 11 , in which the agitators are provided along a portion of the auger not having a flight.

A separator (2), such as a sludge compactor, comprising a perforated tubular screen (4,6), an inlet (8) for mixture to be separated opening into the interior of the screen (4,6), a solids outlet (10) situated at one end of the screen (4,6), and an auger (34) disposed within the tubular screen (4,6) for conveying solids retained by the screen (4,6) from the inlet (8) to the solids outlet (10), wherein at least one delivery device is provided for delivering washing fluid into the interior of the tubular screen (4,6).
:
In use, a sludge comprising a fluid and a solid is fed into the inlet 8. The sludge is conveyed by the auger 34 from the inlet 8 towards the solids outlet 10. As the sludge is conveyed along the screen 4, 6 the fluid flows through the perforations in the screen 4, 6 into the radially outer region of the separation chamber 12, 14. The fluid is then discharged from the outer region of the separation chamber 12, 14 through the fluids outlet 16. The solid particles which cannot pass through the screen 4, 6 are conveyed by the auger 34 along the cylindrical section 6 of the screen until they are obstructed by the retention cone 52.
:
According to a first aspect of the present invention there is provided a separator comprising a perforated tubular screen, an inlet for mixture to be separated opening into the interior of the screen, a solids outlet situated at one end of the screen, and an auger disposed within the tubular screen for conveying solids retained by the screen from the inlet to the solids outlet, the auger having a shaft provided with a flight, wherein delivery devices are provided at a surface of the shaft and are arranged in a spiral about the shaft for delivering washing fluid into the interior of the tubular screen.
:
The flight of the auger may be provided with slots or apertures to allow washing fluid to flow across the flight.
The auger may be provided with agitators. The agitators may be in the form of baffles or paddles which extend along a portion of the auger or in the form of pegs. The agitators may be provided along a portion of the auger not having a flight.
:
The auger 34 comprises two sections: a first section comprising a first shaft 36 and a first flight 40, and a second section comprising a second shaft 38 and a second flight 42.
https://encrypted.google.com/patents/EP2536574A1?cl=en&hl=de

L'invention concerne un séparateur (2), tel qu'un compacteur de boues, comprenant un tamis tubulaire perforé (4,6), une entrée (8) de mélange à séparer débouchant à l'intérieur du tamis (4,6), une sortie de solides (10) située à une extrémité du tamis (4,6) et une vis sans fin (34) disposée à l'intérieur du tamis tubulaire (4,6) destinée à transporter les solides retenus par le tamis (4,6) de l'entrée (8) vers la sortie de solides (10), au moins un dispositif de distribution étant utilisé pour distribuer un fluide de lavage à l'intérieur du tamis tubulaire (4,6).
https://encrypted.google.com/patents/EP2536574A1?cl=fr&hl=de

Pictures :

Fig. 1 sludge compactor separator: https://encrypted.google.com/patents/EP2536574A1?cl=fr&hl=de

The flights of the auger are shown on Fig. 2: https://patentimages.storage.googleapis.com/US20130036923A1/...

I deduct form these drawings that the flights are made of perforated tubes. The phrase can be rephrased by “, in which the agitators are provided along the unperforated tube part” or ““, in which the agitators are provided on the unperforated tube part”.

Considering the previously cited translation
A rideable area sky-blue in colour known as the "blue band" must be provided along the inside edge of the track.
comisariouci.net
Une bande de roulement de couleur bleu azur dite «côte d'azur» doit être aménagée tout le long du bord intérieur de la piste.
comisariouci.net
http://www.linguee.com/english-french/search?source=auto&que...

I propose the following French circumscriptions:

« Les agitateurs sont repartis toute la longueur d'une partie de la vis sans fin » ou « Les agitateurs sont aménagés sur une partie de la vis sans fin »