Split-type range hood having optimal configuration of smoke-collecting case

A split-type range hood having an optimal configuration, comprising:

• a housing including an upper wall, a lower wall, and an intake port, wherein the intake port is fluidly connected to the upper wall and the lower wall;
• and
• a smoke-collecting case covering on the intake port and protruding above the upper wall, wherein the smoke-collecting case includes an outer box and a covering lid, the outer box is fixed to a periphery of the intake port, and the covering lid is fixedly connected to a top portion of the outer box;
• wherein the covering lid has an outlet port, the outlet port fluidly connects the smoke-collecting case to the intake port of the housing, a height of the smoke-collecting case is between 1 cm and 10 cm, so that a fume can pass through the smoke-collecting case to be exhausted outside from the outlet port of the covering lid;
• wherein the intake port is in a shape of a rectangle, the outer box has four box plates each in a shape of a rectangular tube, and the outlet port is in a shape of a round hole, wherein a ratio of an area of the outlet port to an area of the intake port is 0.24:1, and a height of the outer box is 7 cm.