Complex sentence: The kerosene vapour is then forced under pressure through the descending tube (D) to the vapour nozzle (E); here it sprays through a jet in the middle of the burner, where it mixes with air and burns in a sootless blue flame.
Split into simpler sentences: The kerosene vapour is then forced under pressure through the descending tube (D) to the vapour nozzle (E). The vapourized kerosene gas sprays through a jet in the middle of the burner, where it mixes with air and burns in a sootless blue flame.