Gas negative pressure valve

A gas negative pressure valve, comprising a valve body (1) and a valve cover (2), wherein

• a gas inlet and a gas outlet (3) are disposed on the valve body (1), and a gas inlet joint (4) is connected in the gas inlet;
• a drive lever (5) is disposed inside the valve body (1), and a diaphragm assembly is disposed between the valve body (1) and the valve cover (2) and above the drive lever (5);
• a first end of the drive lever (5) is connected to a lower end of the diaphragm assembly, and a second end of the drive lever (5) is connected with a sealing gasket (6) for blocking an inner end of the gas inlet joint;
• the second end of the drive lever (5) is hinged on a sidewall of the valve body (1);
• a reset spring (7) is disposed between the drive lever (5) and a bottom of an inner chamber of the valve body (1), wherein
• the inner chamber of the valve body (1) has a guide passage (8) connected to the gas inlet;
• the second end of the drive lever (5) is connected with a guide shaft (9);
• a lower end of the guide shaft (9) is cooperated slidably in the guide passage (8);
• the guide shaft (9) and the drive lever (5) are configured to swing relative to each other along a longitudinal direction of the drive lever (5);
• a gas-through passage is between an outer wall of the guide shaft (9) and an inner wall of the guide passage (8);
• the sealing gasket (6) is detachably connected to the lower end of the guide shaft (9);
• a mounting shaft (22) is disposed at the second end of the drive lever (5);
• the mounting shaft (22) extends along a width direction of the second end of the drive lever (5);
• a mounting block (23) is disposed at an upper end of the guide shaft (9);
• a horizontally-opening mounting fitting groove (24) is disposed on a sidewall of the mounting block (23);
• and
• the mounting shaft (22) is fitted into the mounting fitting groove (24).