The structure of the fire damper is mainly composed of a valve body and an actuator. The valve body is composed of a shell, a flange, a blade and a blade linkage mechanism. The actuator is composed of a shell, a blade adjustment mechanism, a clutch, a temperature fuse, etc. The actuator controls the rotation of the blade through a metal fusible sheet and a clutch mechanism.
When the temperature of the gas transported in the pipeline reaches the melting temperature of the fusible metal sheet, the fusible metal sheet melts, and the compression spring and the spring pin on the core shaft quickly lay down the clutch pad. At this time, the clutch and the blade adjusting mechanism are disconnected. As the valve body is equipped with two torsion springs, the blade is rotated by torsion. Thus, the actuator of the fire damper adopts the mechanical transmission principle and does not need electricity, gas and other energy, therefore, it can ensure that it can play a role in fire prevention under any circumstances. The on-off of the fire damper is in the open state when the system is deactivated and in normal operation according to the requirements of the system. For example, when the temperature of the conveying gas in the pipe is lower than the melting point of the fire damper of the selected metal fusible sheet, it is in the normal operation state and the valve is open. Only when the operation condition exceeds the normal use state, the valve is automatically closes to achieve the security.
An actuator for fire damper, comprising a base plate 1, a spindle 13, a ratchet 11, a large lever 8, a small lever 5, an electromagnet 7, and a fusible tube seat 16. The spindle 13 can rotate on the base plate 1, the spindle 13 is fixed with a ratchet 11, the large lever 8 is installed on the base plate 1 through a shaft 15, the small lever 5 is installed on the base plate 1 through a shaft 6, and a torsion spring 19 is installed on the shaft 6, the bump 10 is installed on the large lever 8, the electromagnet 7 is connected with the small lever 5 through the pin 18, the fusible rod 4 is installed in the fusible tube seat 16, one end of the reset tension spring hook 2 is stuck on the fusible rod 4, and the other end is hooked on the small lever 5, and the balance is maintained through the two reset tension springs 3. The ratchet 11 and the bump 10 are engaged with arc teeth, and the large lever 8 is L-shaped, one side is made of a boss 22, and the fire damper ratchet 11 is made with a protrusion 21 corresponding to the boss 22. The advantage of the utility model is that the ratchet and bump wear is small, the force angle is reasonable, and the valve with large torque can be controlled. The ratchet can push the lever to automatically reset.

Construction and installation points of smoke exhaust fire damper.
1. Fire damper can be interlocked with ventilator and exhaust fan.
2. The operating mechanism side of the valve should have a net space of not less than 200mm to facilitate maintenance.
3. Before installing the valve, it is necessary to check whether the operating mechanism of the valve is in good condition and whether the action is flexible and effective.
4. Fire dampers shall be installed in the air duct section close to the wall or floor slab. The fire dampers on both sides of the partition wall of the fire compartment shall not be more than 200mm from the wall surface. The pipes and their thermal insulation materials within 2.0m on both sides of the fire dampers shall be made of non-combustible materials.
5. Fire dampers should be set up separately to prevent pipe deformation from affecting its performance in case of fire.
6. The fuse piece of the fire damper should be installed on the side with greater fire risk.
According to the role of fire dampers can be divided into fire dampers, fire dampers and smoke fire dampers.

Fire damper shall be set on the return air-drying pipe of the air-conditioning system. Its functions are as follows:
a) Prevent the fire from spreading to other areas through the air duct.
B) Prevent the flue gas from spreading to other areas through the air duct.
c) Prevent the smoke exhaust fan or smoke exhaust equipment from being damaged by fire.
The working principle of the system is different, the principle of the type of fire valve is not the same, the main purpose is to prevent the spread of fire.

Fire dampers must be installed at the following locations:
a) Fire dampers are set on the air supply and return air pipes that pass through the fire zone, including the fire wall, partition wall of the fire zone and the air duct of the floor.
B) Ventilation of partition walls and floor slabs across the machine room, air supply and return air main pipes of the air conditioning machine room.
c) Air supply and return pipes at the partition wall and floor slab of the room with high fire risk.
d) The air duct passing through the deformation joint is on both sides of the deformation joint.
e) The vertical air duct is connected with the horizontal air duct of each layer.
Shandong Xingheng Environmental Technology Group Co., Ltd. is located in Luquantun Development Zone, Dezhou, Shandong Province, the hometown of glass fiber reinforced plastic in China. The company has three-level qualification for construction mechanical and electrical installation engineering, three-level qualification for environmental protection engineering, and safety production license. It is the first in the industry to pass ISO9001 quality management system certification, ISO14001 environmental management system certification, OHSAS18001 occupational health management system certification, an axial fan invention patent, a fan utility model patent, EIA, three at the same time waiting for complete procedures