Abstract: The present invention concerns a glass fibre manufacturing plant comprising a forehearth forming a passage for conveying molten glass and defined by a first and second opposite longitudinal walls, wherein each longitudinal wall is made of a refractory masonry comprising a cavity of width, Wc, and height, H1c, formed by a floor defined by a base wall, by lateral walls defined by two spacer bricks and by a ceiling defined by a lintel resting on each of the two spacer bricks, and further comprising a support block (20) comprising a hot cuboid portion of width, w, and height, h, wherein w<Wc, and h<H1c, said hot cuboid portion being reversibly inserted in the cavity, thus defining a gap surrounding the hot cuboid portion of the support block when positioned in the cavity, said gap being filled with a resilient material (29), said forehearth being characterized in that, the masonry comprises a spacing element hindering the thermal expansion of the two spacer bricks, such that the distance, Wc, between said t

Abstract: The present invention concerns a glass fibre manufacturing plant comprising a forehearth (31) comprising a longitudinal wall provided with at least one burner assembly comprising: (A) a burner block (20) made of a refractory material and comprising a through-passage and comprising a hot surface (20H) forming a portion of the longitudinal wall (31 L); and (B) a burner sub-assembly comprising: (a) an oxy-burner (1) comprising a downstream end ending at a free end of the downstream end, wherein a cross-sectional area of said downstream end of the oxy-burner body decreases towards the free end of the downstream end; characterized in that, the burner sub-assembly further comprises: (b) a cooling unit (3) comprising: ?a cooling plate (5) comprising an aperture which geometry matches the geometry of the downstream end of the oxy-burner which is inserted in said aperture to form a thermal contact therewith; •a cooling channel (3C) defined by walls and comprising an inlet (3U) and an outlet (3D) for circulating a refr