Контекст:

The vacuum trays of the belt filter consist on the upper side of perforated, removable wedge-wire screen, sloping side walls and a duct system connected with the filtrate collection pipes on the bottom side.
All filtrate drain pipes from various filtration zones discharge into this collection pipe from which the desired individual filtrates are drained separately by way of blank flange separations.
The vacuum valves are connected with the vacuum station via vacuum proof pipes or hoses supplied by others. The filtrate collection tube is mounted to the belt filter frame or housing.

Большое спасибо :))

ИМХО

filtrate drain pipes - трубы слива фильтрата

filtrate collection tube - труба коллектора фильтрата

(все имхо)