How many different types of protection are there for elevators?

In the actual operation of the elevator, the designers have designed a variety of safety devices and adopted a variety of safety measures to eliminate these unsafe factors. As long as the elevator is used correctly and regularly maintained and inspected, there will be no safety accidents, so as to ensure that the elevator is a perfect transportation equipment.

Safety protection before the elevator is running

1. Grounding

The metal shells of all electrical equipment on the elevator are well grounded, and their grounding resistance values ​​are greater than 4W. The protective grounding system of the elevator is good, and the insulation strength of the electrical equipment is tested during installation. Therefore, the elevator equipment is safe to use electricity, and it is not easy to get electric shock or leakage.

2. Traction rope

The traction rope bears the entire hanging weight of the elevator, and its quality is directly related to the safety during operation. The characteristics of the traction rope are high strength and good flexibility. In addition, the number of steel wire ropes for passenger elevators and medical elevators is not less than 4, the static load safety factor is not less than 12, and the tensile strength of the rope head combination is not less than the tensile strength of the steel wire rope. Therefore, high-quality traction ropes ensure the safety of elevator operation.

3. Brake

When the elevator is not running, the car can stay in its original position steadily without sliding up and down. As long as the traction wheel does not rotate, the car will not move. The brake ensures the safety of the elevator before operation, and it plays an even more important role during operation and when an accident occurs.

4. Overload device of the car

In order to enable the elevator to operate normally within the designed load range, an overload device is set on the car. Generally, when the load reaches 110% of the rated load, the elevator overload protection device takes effect, the overload buzzer sounds, the car door cannot be closed, and the elevator will automatically cut off the control circuit, making the elevator unable to start.

Safety protection that works during elevator operation

1. Hall door and car door

To start the elevator, one of the important conditions is that all hall doors and car doors must be closed. As long as one door is not closed, the elevator cannot start. This is because mechanical and electrical interlocking devices are installed on each door. If the door is not closed, the circuit will not work and the elevator cannot start. To start the elevator, in addition to the car door and hall door being closed, the car top safety window switch, safety clamp switch, pit bottom switch, upper and lower limit switches, etc. must be in normal state before it can be started.

2. Overload test

Before the completion of the elevator, the elevator has been overloaded. This test ensures the normal operation of the elevator in the future.

Safety protection that works when an accident occurs during elevator operation 1. Separation of lighting circuits and power circuits When the elevator fails, in order to stop the elevator from running, the power supply must be cut off, but at this time, only the power supply is cut off to make the elevator unable to run, and at the same time, it must be ensured that the lighting, ventilation, and alarm devices in the car have electricity to avoid darkness in the car and inability to communicate with the outside world after the elevator loses power, causing fear and panic in passengers. 2. Car top safety window and safety window switch There is a safety window that opens outward on the top of the car. Its function is to be used for emergency and maintenance when an accident occurs in the elevator. People can evacuate the car from this window. In addition, when the safety window is opened, the safety window switch located at the window will be activated, which can also cut off the control circuit and make the elevator unable to start. There is also an exhaust fan on the top of the car, leaving a passage for air in and out, so that people in the car will not feel stuffy.

3.Buffer When all the above safety devices fail (this possibility is very rare), the elevator car or counterweight rushes straight into the pit of the shaft, and the last safety device, the buffer, is used to ensure the safety of the elevator. When the car or counterweight presses on the buffer, the buffer is compressed and deformed, causing the car or counterweight to rebound. After rebounding several times, the car or counterweight is buffered and finally stops.