Explosion-proof Smoke Fire Alarm Sensor ALF-FB/684F

I. Overview

       ALF-FB/684F explosion-proof smoke and fire detector is a non-coding switch type (relay output) detector, which can be used with fire alarm controllers of any manufacturer at home and abroad.

      When the on-site smoke concentration exceeds the set threshold, the indicator light of the detector is always on and an alarm signal is sent to the controller. Only after the system is reset or temporarily power-off and power-on again, the indicator light resumes flashing (patrol inspection) state.

2. Features

       The detector adopts a new type of scattering technology and imported photoelectric devices to improve the stability and consistency of the sensor, and adopts a unique labyrinth design, which has good anti-insect, dust-proof, and anti-interference performance of external light. Novel structure, beautiful appearance, stable and reliable performance, strong moisture resistance.

       The detector has been equipped with a HADS safety barrier. The safety barrier adopts resistive and transistor dual electronic switch circuit, which has fast start and control speed and can be automatically restored.

3. Technical characteristics

1. Explosion-proof form: intrinsically safe-flameproof composite type

2. Explosion-proof mark: Exd (ib) IIBT6

3. Ambient temperature: -10℃~+55℃

4. Relative humidity: ≤95% (non-condensing)

5. Atmospheric pressure: 80~110KPa

6. Working voltage: DC24 V±4V

7. Quiescent current: ≤120uA

8. Alarm current: 10mA≤I≤30Ma

9. Response threshold: 0.10dB/m~0.27 dB/m

10. Alarm reset: instantaneous power failure (10s Min, DC2.5V Max)

11. Power-on time: ≤10s

12. The highest wind speed: 7.6m/s (1500fpm)

13. Alarm confirmation light: red, flashing periodically during normal monitoring, and always on when alarming.

14. Safety barrier parameters: Ui=28VDC; Ii=60mA

15. Protection area: When the height of the space is 6m~12mm, the protection area of a detector is 80m for the general protection site. When the height of the space is less than 6m, the protection area is 60m.

16. Dimensions: 170×120×93 mm

17.Installation size: 104 mm

18.Weight: 1.55kg

4. Structural features and working principle

图1    探测器外形示意图

5. Working principle

       The detector uses the principle of infrared scattering to detect fire. The circuit mainly consists of an infrared transmitting part and a receiving part. The transmitting tube and the receiving tube are placed in an optical dark room. The optical dark room can shield external stray light interference, but does not affect the entry of smoke and dust. In a smokeless state, only weak infrared light is received. When smoke and dust enter, the received light signal is enhanced due to the scattering effect. When the smoke and dust reach a certain concentration, an alarm signal can be output. In order to reduce interference and reduce power consumption, the transmitting circuit adopts intermittent operation, which can increase the service life of the transmitting tube.

       The alarm output signal adopts the switch quantity (relay passive contact) mode, which can be used with fire alarm controllers of any manufacturer at home and abroad.

Five, test

After opening the box, the user should immediately perform a performance inspection on the product. The inspection process is as follows:

Connect the DC24V power supply to the power side of the test wire (red and black, no polarity), the detector enters the inspection state, at this time, the indicator light is flashing; use a multimeter (electrical blocking) to test the passive contact wire (green) It is a normally closed contact, and the yellow is a normally open contact). At this time, the normally open contact should show infinite resistance, and the normally closed contact should be closed.

Remove the dust cover, blow smoke into the detector, the detector will output an alarm signal, at this time, the indicator light is always on; use a multimeter (electric barrier) to test the passive contact wire, and the resistance should be zero at this time. Indicates that the passive contact is closed. The product is qualified.

If the product fails the above-mentioned inspection, please do not open the explosion-proof housing, and you should contact us immediately to discuss a solution.

Warning: The six wires connected to the factory are used to test the product. When the product is connected to the system, the test wires should be removed and connected with a cable with an outer diameter of about 8mm, otherwise the detector will lose its explosion-proof performance.

6. Installation and wiring

    1. Installation method

       According to the site situation, use M6 expansion screws to fix the explosion-proof enclosure on the ceiling through the detector fixing claws. The cable entry device adopts a pressure-sealed rubber ring structure, the cable outer diameter is about 8mm, and the explosion-proof cable inlet is M22×1.5 internal thread. The schematic diagram of the detector installation is shown in Figure 2.

    2. Wiring:

       Loosen the fixing screws of the detector shell, open the explosion-proof cavity, remove the test wire, and use a cable with a diameter of about 8mm as the system wire.

       Connect the DC24V power cord in series from one side of the wire inlet and connect it to the input terminal D of the circuit board (no polarity); K is a normally open passive contact, and B is a normally closed passive contact.

See Figure 3 for wiring diagram.

图2   探测器安装示意图

图3   接线端子图

D D is 24v power supply

G K is normally open passive contact output

B G is normally closed passive contact output

Note: During the installation process, do not remove the dust cover to prevent dust from entering and affecting the accuracy of the detector. The dust cover should be removed when the system is running normally.

Seven, common faults and maintenance

       In the event of a fault, first check whether the external wiring is correct and whether the fastening screws are loose. If it is normal, then open the shell to observe whether the circuit board has any abnormalities such as false soldering or burning.

During the use of the detector, the possible malfunctions and solutions are summarized as follows:

1. No patrol inspection. Check whether the power supply voltage meets the requirements.

2. No alarm Check the transmitting tube, receiving tube, amplifying circuit, etc.

3. False alarm Check whether the maze is too dirty.

8. Maintenance

1. The detector should be installed before commissioning, and should be properly kept before installation; and corresponding dust-proof, moisture-proof and anti-corrosion measures should be taken.

2. The detector should be dust-proof, and the dust-proof cover must be taken off after the project is officially put into use.

3. The detector is cleaned at least once a year to ensure the normal operation of the system.

4. If the detector is found to have frequent false alarms in the engineering, the maze should be cleaned, and the maze can be replaced if necessary.

Steps to clean the maze:

a) First, pinch both sides of the labyrinth body and gently shake it to pull it out.

b) Clamp an alcohol cotton ball with tweezers to carefully clean the inner cavity of the labyrinth, taking care not to leave cotton wool in the labyrinth.

c) Install the maze body.

5. After the detector is cleaned, reinstall the detector, and then perform the test.

6. A simulated fire alarm test should be carried out every six months to test whether the detector is working properly.

Nine, matters needing attention

1. The dust cover must be taken off after the project is officially put into use. Please keep the dust cover for future use.

2. The dust cover can effectively restrict dust from entering the detector, but it is impossible to completely prevent the floating dust particles in the air from entering the detector. Therefore, it is recommended to remove the detector before civil construction, decoration or other dust-generating activities begin, but the relevant management department must be notified.

3. During maintenance, care should be taken to avoid damage to the detector.

4. There should be no shelter within 0.5m around the detector.

5. The horizontal distance between the detector and the air supply hole of the air conditioner should not be less than 1.5m.

6. The horizontal distance from the detector to the wall and beam side should not be less than 0.5m.

7. When the detector is installed on the ceiling of the inner walkway with a width less than 3m, it should be arranged in the center. The installation distance of the detector should not exceed 15m, and the distance between the detector and the end wall should not be greater than half of the installation distance of the detector.

8. The detector should be installed horizontally. If it must be installed at an angle, the inclination angle should not be greater than 45°.

9. The base of the detector should be installed firmly, and its wire connection must be reliable.

10. The confirmation light of the detector should face the main entrance that is convenient for personnel to observe.

11. It is strictly forbidden to conduct live disassembly in flammable and explosive places.

12. Do not damage the explosion-proof surface during installation and keep it clean. The fastening screws of the explosion-proof surface should be tightened evenly. Be careful not to include wires or other foreign objects on the explosion-proof surface.