Fire door release switch automatic control principle
Fire door release switch (refer to model ZDK 905) panel, external dimensions 150mmX150mm × 50mm, similar to the 86 series switch panel, usually mounted on the wall or homemade bracket, about 5 m from the ground height. The practice is similar to that of a normal wall switch, except that the dedicated junction box must be pre-embedded because the fire door release switch is subject to the impact and pull-out force of the door leaf. There is a groove on the release switch panel, and a corresponding metal small handle is mounted on the corresponding fire door leaf. The small handle is usually embedded in the groove of the fire door release switch and is buckled, and the fire door release switch pulls the fire door leaf to make the door at Normally open state. There is a chain pull bolt on the fire door release switch. Some products are a button. Pull or press to manually release the metal small handle (the door can also be forced to pull in the emergency situation). The fire door leaf door relies on the door closer spring force and sequencer to open the door. Close tight. The fire door release switch keeps the holding force of the stacked small handles adjustable within 10 to 50 kg.
The fire door release switch is usually operated by electromagnetic. The power supply can be directly taken from the DC24V DC external control power supply of the linkage module. The working current is less than 0.3A, the energization time is less than 0.5s, and the coil circuit is automatically cut off after the fire door is released. Since the fire door is generally linked by the smoke detector and the probability of closing multiple fire doors is small, the impact on the DC external control power supply is small. When there are many fire doors being controlled, the external control power supply should increase the capacity.
The fire door release switch adopts five wires (three feedback signal wires of two coil wires), and a normally open and a normally open contact reflects the working state of the fire door.
Another kind of fire door release switch adopts temperature control, and uses memory alloy as temperature control component. When the ambient temperature reaches 70 °C, the temperature control component action blocking member is disengaged, and the fire door will be closed under the action of the door closer elastic force. The principle is similar to that of a fire damper; there is also a composite product called a dual-control fire door release switch (reference model: ZDK-902).
The fire door release switch described above is not energized under normal conditions, and is only energized instantaneously when interlocked; in addition, the fire door release switch must be connected to the fire-fighting power supply under normal conditions, and the fire door is warmed by the electromagnet suction. Usually consume electricity. The fire alarm linkage module releases the fire door by cutting off the electromagnet power supply, and can also be manually controlled and has a feedback signal function.
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Label: Fire door release switch automatic control principle
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