Safety device used in an escalator
Escalator safety is most important part of the system for the safety of passanger and machine most of escalator contains these common safety device.
What are the safety devices for escalators?
Escalators are equipped with various safety devices to ensure the safety of passengers and to prevent accidents. An escalator is more unsafe than an elevator because an escalator has more accident happened. Here's a point-wise detailed description of some of the common safety devices used in escalators:-
Located on both sides of the escalator steps, skirt brushes prevent clothing, shoes, or other objects from getting caught between the moving steps and the sidewall. They act as a barrier to keep passengers' belongings and clothing clear of the moving parts.
Yellow or contrasting-colored demarcation lines are often painted on the steps, marking the safe standing area for passengers. These lines indicate where passengers should stand to maintain a safe distance from the comb plates and side skirts.
Comb Impact Switches:-
The comb plate is located at the bottom and top of the escalator and comb placed on comb plate. It helps guide passengers onto and off the moving steps. Comb impact switches are sensitive to pressure and can detect obstructions or excessive load at the entrance and exit. If an obstruction is detected, the escalator stops moving.
Comb light & truss light:-
Comb light & truss light in an escalator also counted as safety device. Comb light found in top and bottom side of escalator at both side of comb plate it ensure proper illumination for passenger in case of building light not working properly.
Emergency Stop Button:-
Typically found at the top and bottom of the escalator and sometimes on the center, an emergency stop button allows passengers, maintenance personnel, or security staff to stop the escalator in the event of an emergency.
Safety Sensors and Detectors:-
Various sensors and detectors monitor the escalator's operation. These sensors can detect issues such as abnormal speed, motor overloads, 3 phase monitor and overheating, which can trigger an emergency stop. These task normally done in main controller of escalator where PCBs or drive installed.
Handrail Speed Monitoring:-
To ensure that the handrails move at the same speed as the steps, speed monitoring devices are installed. If the handrail moves too quickly or slowly, it can indicate a problem with the escalator's operation.
Motor Speed Monitoring:-
Motor speed monitor by speed governor for stop the escalator in over speed or under speed condition. Motor speed sensor are installed on motor for calculating speed.
Missing Step Monitoring:-
Missing step sensor is a safety device installed in escalator for counting steps if it detect a missing step it stop escalator immediately. Its normally metal detector type sensor.
Handrail Inlet Guard:-
Handrail inlet guard also a safety device installed at both top & bottom side of escalator handrail it contain rubber or brush with safety switch for stopping foreign object enter in balustrade with moving handrail.
Step Chain Safety Device:-
Step chain safety device stop the escalator if the step chain break or stretches beyond set limit. It is installed in bottom pit of escalator at both side under step chain tension spring.
Drive Chain Safety:-
Drive chain safety device stop the escalator in case of broken or loose drive chain. It is installed in top pit of an escalator.
Platform Open switch:-
Floor plate or platform open switch stop the escalator when the floor plate or pit are open. It is installed in both pit.
Step Level Device:-
Step level safety device are found on top and bottom side where horizontal step available, it stop escalator when it find horizontal level of steps missing.
Anti static brush & roller:-
Anti static brush and anti static roller are installed in escalator for discharging static charge of handrail belt and steps.
Broken Step Device:-
Broken step or step sag device found in truss at top and bottom side, it is a rod of metal connected with switch when step broken or step chain roller broken it detect and stop escalator.
Step upthrust is a safety device used in escalator at curve of escalator it operate when step jump on curve. installed under jumping track check step roller running condition.
Safety balustrades are vertical panels on both sides of the escalator. They provide a barrier between passengers and the moving parts. If the balustrade is pressed, it can trigger an emergency stop.
Most escalators are equipped with safety brakes or Auxiliary break that engage in case of a malfunction, drive chain breaking, travelling direction change due to overload, power failure or overspeed condition. These brakes can quickly bring the escalator to a halt to prevent accidents.
Safety Skirt Guard Sensors:-
Sensors or switches in the skirt guard area can detect any objects or debris that might become lodged in the gap between the skirt guard and the steps. If an obstruction is detected, the escalator stops.
Handrail Infrared Sensors:-
Infrared sensors can detect the presence of hands on the handrail. If a passenger's hand is detected, it ensures that the handrail continues to move at a safe speed and doesn't suddenly speed up or slow down.
Water level monitor:-
Water level sensor used in outdoor escalator and installed in pit, in case of rain when water enter in pit float switch or water level sensor detect water and stop escalator.
Emergency Power Shutdown:-
In the event of a power failure or other emergency, escalators are often equipped with a backup power source that allows for a controlled stop and safe evacuation of passengers. In case of power failure if escalator are overload by passenger that time auxiliary break lock the sprocket and stop slipping escalator.
These safety devices are essential for the smooth and secure operation of escalators. Regular maintenance and safety inspections are crucial to ensure that these devices function correctly and that escalators remain safe for passengers.