Elevator safety precautions

With the development of the city, high-rise buildings are a way for the city to solve the shortage of land resources, and high-rise buildings have become the protagonist of urban architecture. According to relevant national regulations, buildings with more than 8 floors need to be equipped with elevators. In recent years, elevator safety accidents have occurred frequently, which is very worrying. Here are some tips for elevator security.

1. Elevator monitoring and wiring related skills

From the perspective of integrated wiring, the wiring of the elevator monitoring system becomes particularly important. The wiring methods of the elevator monitoring system network cable are mainly as follows:

(1) The location of the video cable out of the elevator shaft: the ideal choice should be in the middle of the well, because the length of the accompanying video cable in the well is only about a little more than half of the depth of the well, the shortest, and the naturally introduced interference is also minimal; but engineering Such qualifying requirements can only be obtained based on circumstances, and actual projects may not be allowed.

(2) In the past, when the principle was not understood, most of the outlet positions were to go with other accompanying cables and walk out from the top or bottom of the cable well. In this case, considering that only half of the cable is moving, and the other half is only a fixed extension connection, not moving, we call this part "the fixed cable"; this provides a possibility: the half of the moving cable It can only be bundled with other accompanying cables; the other half of the fixed cable can choose to be routed separately from the accompanying cable. The video cable should be closely attached to the vertical wall of the well in the elevator shaft, and this part of the cable should be passed through the metal tube. Or take a metal slot to shield the influence of interference on this part of the cable, which is more effective.

(3) When bundling the video cables of the accompanying moving part with other accompanying cables, the designer should fully understand the structure and distribution of the other accompanying cables. When bundling, the video cables should be kept away from cables with high current and high frequency, and close to low current and low frequency Cable bundling; here, even the choice of 1 cm may have to be fought, because the effect of interference is at least inversely proportional to the square of the distance.

(4) The "ground" of the video signal, such as the metal casing of the camera, the casing of the NC head, and the outer conductor of the coaxial cable, must be insulated from the elevator car, guide rails, etc., which must be paid special attention when installing the camera. The power supply of the camera should be preferably centralized DC power supply, followed by the choice of car lighting power, not power power. For power supply, control and other monitoring cables, use shielded cables as much as possible to prevent the leakage of interference signals.

(5) The video cable from the elevator shaft exit to the control center should go through a metal pipe or a metal slot to shield the influence of environmental interference along the way on this part of the cable, and pay attention to this part of the shielding and the shielding in the elevator shaft. connection.

It is understood that the video signal line should be laid from the monitoring center to the pre-reserved video interface of the elevator machine room. The video signal line from the elevator machine room to the elevator car should be wired by a professional elevator manufacturer (one by one when laying the accompanying cable) , Professional elevator construction units reserve video interfaces in the elevator machine room (the same principle of power supply). If you need to install a floor display, you need to coordinate a professional unit to reserve 220V power in the elevator car.

2. Selection skills of elevator surveillance cameras

(1) Selection of elevator monitoring cameras

Installing surveillance cameras in elevators is an effective way to enhance elevator safety. On the one hand, it is to supervise the behavior of people in the elevator. On the other hand, when an accident occurs, the safety of people in the elevator can be observed in time. According to the operating environment of the elevator, the cameras installed in the elevator are mainly domed cameras.

When most elevators are not in use, the fluorescent lamp in the car is in an energy-saving off state. If you need to monitor the cabinet for 24 hours, you can choose the infrared hemisphere camera, otherwise you can choose the ordinary hemisphere camera (when someone enters the elevator car) When the lamp will automatically turn on). Because the elevator car is very short, it is inevitable that people will destroy the equipment at will. At this time, the user can choose an explosion-proof hemisphere camera.

(2) Special requirements for anti-signal interference of elevator cameras

It is worth noting that the motor outside the elevator will cause great signal interference to the monitoring video signal, so there are special requirements for the elevator camera in this regard.

First of all, from the choice of equipment, engineering companies and users should try to choose mature equipment on the market and hemispherical cameras with strong anti-interference capabilities for elevators. At the same time, use special cables for elevators when wiring, taking care not to damage the cables. As far as the power consumption of the camera is concerned, use the monitoring power supply interface reserved by the elevator as much as possible to prevent the occurrence of accidental leakage accidents; while the interference problem cannot be solved in the normal mode, anti-interference measures can be considered in the transmission line.

At present, most elevator monitoring systems are built using the analog signal cable transmission mode. The connection is displayed on the display platform of the monitoring room. As for the display position, there is no special requirement. It is displayed in a conspicuous and easy-to-view position according to user needs. That's it. Due to the small elevator space and crowded people, once an accident occurs, it is difficult to rescue. Then, when installing the surveillance camera, you should pay more attention to the strict operation process and installation specifications; do not connect and pull unrelated cables randomly, and the interface of the line should meet the specifications. Can not be arbitrarily connected; the quality of the products used should be as reliable as possible (such as: cameras, transformers, cables, etc.), and relevant test reports and certificates are required. In this way, we can reduce the occurrence of various accidents.

In addition, the longer the video line, the greater the possibility that the existing clutter signal interferes with the video, and the quality of the video signal transmission will decrease; in some large industrial areas, where centralized monitoring is required, this analog signal transmission System will be useless. At this time, engineering companies and users can use the digital signal transmission mode to reduce signal interference and simplify wiring, or use wireless transmission to avoid the cumbersome construction wiring.