Fire protection device, oxygen therapy instrument and ventilation treatment system

A fire protection device, wherein the fire protection device comprises a housing, a valve body, a torsion spring, and a meltable member;

• a fluid passage is provided in the housing, the fluid passage is provided with a first opening and a second opening, and the first opening and the second opening are used for communicating with a pipeline of an oxygen therapy instrument or a patient end, respectively;
• the valve body is located in the fluid passage and is rotatably connected to the housing;
• the valve body is provided with an accommodating cavity, and the fluid passage and the accommodating cavity are two spaces independent from each other;
• the torsion spring is embedded in the accommodating cavity so as to drive the relative rotation of the valve body and the housing;
• the meltable member is disposed on an inner wall of the fluid passage;
• when the meltable member is in a non-molten state, the meltable member supports the valve body to be in a first position, and both the first opening and the second opening are in an open state;
• and
• when the meltable member is in a molten state, the torsion spring drives the valve body to rotate to a second position, and at least one of the first opening and the second opening is in a closed state.