Elevator safety knowledge science

Abstract:1. Will the passenger elevator fall from a height at a […]

1. Will the passenger elevator fall from a height at a high speed?

A normal elevator will not fall from a height at a high speed. There are two safety protection measures in the elevator design to prevent the elevator from falling at high speed: First, there are generally more than four wire ropes suspending the car, and the safety factor is 12 times, a single wire rope is enough to bear all the load; If it is broken, there is also a speed limiter safety gear device to prevent the elevator from falling at high speed. When the elevator is overspeeding downward, the speed limiter will trigger the safety gear action when the speed governor detects that the elevator is overspeeding, and the safety gear will tightly bite the car guide rail to stop the elevator. Just like the brake of a bicycle, the handbrake is the speed limiter, the wire rope of the speed limiter is the handbrake line, and the brake shoe is the safety gear.

In 1854, at the Crystal Palace Exhibition in New York, Eliza Graves Otis publicly displayed his safety lift. Standing on the platform of the elevator, he cut the cables in public, and the platform descended only a few inches before it came to a safe stop. This is the anti-fall effect of the speed limiter safety gear device. It is precisely by solving the problem of preventing elevators from falling from a high place at high speed that elevators are widely used as safe and secure equipment.

2. The elevator often fails to stop. Is the elevator still safe?

A variety of safety measures are adopted in the elevator design to eliminate the dangers of falling and topping: one is to monitor the status of each component of the equipment. Once the components do not work according to the design requirements, the elevator will stop running. For example, the device to prevent the elevator from falling; various safety switches that monitor whether the electrical and mechanical components work normally; the door locks of the landing doors and the door locks of the car doors to prevent people from falling; the other is to monitor the behavior of users, such as preventing the elevator from overloading device; light curtain protection device to prevent people from being caught in the car door, etc. If any safety protection device does not work properly, the elevator will stop. Although it will bring inconvenience to everyone's normal use of the elevator, it will prevent the danger caused by the elevator running with illness.

3. All the signal lights of the car buttons are suddenly turned off. Is there any danger when the elevator "falls" directly?

Which floor the elevator stops at is determined by the control system according to the position signal of the elevator. Sometimes the position signal of the elevator will be lost or disordered due to interference and other reasons. At this time, the elevator will return to the base station according to the preset program to regain the accurate position signal. (Sometimes up, depending on the location of the base station), the down speed is the normal running speed or lower than the normal running speed. In this case, some passengers will mistakenly think that the elevator is out of control. In fact, it is a fault self-recovery function of the elevator. There is no danger, please don't panic.

4. Will you suffocate if you stay in the car during a power outage?

The elevator car has ventilation holes leading to the hoistway, the hoistway has ventilation holes leading to the machine room, and the machine room has ventilation holes leading to the outside of the building, so there is no need to worry about suffocation if you stay in the car during a power outage. In many cases, the feeling of suffocation caused by passengers trapped in the car is caused by excessive tension. Therefore, if you are trapped, please do not panic too much, keep calm and wait patiently for rescue.

5. Do you know which positions are dangerous when riding an escalator?

One is the bottom edge of the handrail. Because the handrail is moving, if you put your fingers into the gap, it is easy to pinch your fingers and cause injury; the second is the gap between the steps and the skirt next to them. The skirt next to it is fixed, while the steps are in motion, there is a gap of about 4mm between them. Thin items such as children's shoes, shoelaces, and long skirts are easy to be caught, and the gap will become larger after being caught, causing injuries to the hands and feet; the third is the intersection of the pedals and steps at the entrance and exit. Here, the pedal is fixed, and there is a comb plate to prevent debris from entering the steps. Thin items such as children's shoes, shoelaces, and long skirts are easily caught between the comb plate and the steps. Therefore, pay special attention to this area when entering and exiting the entrance and exit of the escalator; the fourth is the intersection area between the escalator and the bottom beam or column of the building. If a passenger sticks their head or hand out of the escalator, when the escalator runs to this area, the passenger's head or hand may get caught at the triangular intersection of the escalator handrail and the building beam or column, causing serious injury.

6. Please pay attention to check the "inspection sign" when taking the elevator

The "inspection sign" should be posted in the elevator car, and the current date does not exceed the "next inspection date" in the sign. The regulations stipulate that every elevator needs to be inspected regularly every year. The safety performance of elevators that have undergone regular inspections meets the basic requirements of the state.

7. Why can't you take an overloaded elevator?

When the elevator car carries more than the rated load, the elevator will give an overload alarm and the elevator cannot start. Passengers who enter later should exit the car actively.

The rated load capacity is the main parameter of elevator design, and the elevator power, brake braking capacity, traction conditions, etc. are all directly related to the load capacity. In case of serious overload, the traction rope will slip on the traction sheave and cause the ladder to slip, or the brakes have insufficient braking capacity and the ladder will slip. The ladder slip is an extremely dangerous failure of the elevator, which may cause equipment damage or personal injury in serious cases.

The elevator mainly limits the load capacity of the elevator car by limiting the area of ​​the car and setting the overload protection device. The overload protection device is not a safety contact and a safety circuit, and its safety level is not high, so the possibility of failure cannot be ruled out. At this time, the load is mainly limited by the capacity of the elevator car. The area of ​​the elevator car is designed according to the area required for an ordinary adult to stand. The nameplate posted in the elevator car indicates the rated load capacity and number of people of the elevator. Do not force the passengers beyond the rear. In reality, an elevator with a rated load of 1000 kg and 13 passengers has happened, and the car has actually loaded 20 passengers. It happened that the overload protection device of the elevator did not work normally, and the overspeed protection device of the elevator terminal did not work. Finally, the car lost control and fell into the pit, causing many fractures or sprains.

8. Why is the elevator sometimes broken during operation after maintenance?

As a highly intelligent equipment, the quality of the whole machine design, component manufacturing, installation, and maintenance directly affects the reliable operation of the elevator. Elevator failures are not necessarily due to improper maintenance. High-quality preventive maintenance can effectively check the status of equipment-related components and eliminate hidden troubles, but it cannot solve all kinds of problems in all elevator quality links. There is no guarantee that the elevator will not fail at all.

9. What should I do if the home elevator is aging?

Elevator is a product with a high degree of mechatronics, including manufacturing quality, installation quality, maintenance quality, and use environment quality. The quality of each elevator has an impact on the use effect, failure rate and service life of the elevator. Although the elevator can meet the safety standards in the later period of its life cycle, the elevator's Reliability is greatly reduced, and failures occur frequently. Some elevators have increased energy consumption and high operating costs. At this time, it is necessary to evaluate the elevator. If the reliability of the elevator cannot be effectively improved after overhaul, it is necessary to consider reconstruction or replacement. The cost of overhaul, renovation and replacement is generally paid from the special maintenance fund of the property or shared by the elevator owner.

10. Why does the elevator that has passed the inspection still fail?

Answer: First, elevators are frequently used mechanical equipment, and there is the possibility of failure objectively; second, due to the limitation of social costs, inspection resources and other objective conditions, the state stipulates that the inspection of elevators must be carried out in strict accordance with the inspection items stipulated in the inspection rules. These items are limited in number (for example, the current regular inspection items for vertical elevators are 52 items), and they mainly reflect the requirements of safety performance, and involve less requirements in terms of reliability; third, the reliability of elevators is generally related to product cost and maintenance cost. Closely related, low-cost elevators generally have a higher failure rate. This is somewhat similar to the difference between a high-end car and a low-end car.

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