Blocks for receiving a molten material, especially glass, and fiberizing installation provided with such blocks

A flow block, comprising:

• a flow block height;
• an upper face;
• a lower face;
• a longitudinal length, being of greater length;
• a lateral width, being of lesser length;
• a single cavity comprising a flow channel bounded by a wall;
• an inlet orifice, on the upper face, and an outlet orifice, on the lower face, at two opposed ends of the flow channel, respectively,
• wherein the upper face comprises a first lateral edge and a second lateral edge, a first longitudinal edge and a second longitudinal edge, a longitudinal mid-plane extending along the longitudinal length, bisecting the first and the second longitudinal edge, and a lateral mid-plane, perpendicular to the longitudinal length and bisecting the diameter of the inlet orifice along the longitudinal length, wherein the inlet orifice has an asymmetrical shape with respect to the lateral mid-plane and in that the inlet orifice comprises an upstream part and a downstream part opposite the upstream part with respect to the lateral mid-plane, the upstream part being wider than the downstream part.