Topic 6 Elevators and Escalators - PDF

Hijjawi Faculty for Engineering Technology Department of Architectural Engineering First Semester 2024/2025 Electrical and Mechanical Systems AE 475 Dr. Muna M. Alibrahim  Topic 6 Elevators and Escalators Escalators and elevators have had...

Hijjawi Faculty for Engineering Technology Department of Architectural Engineering First Semester 2024/2025 Electrical and Mechanical Systems AE 475 Dr. Muna M. Alibrahim  Topic 6 Elevators and Escalators Escalators and elevators have had a tremendous impact on contemporary design and architecture. Escalators and elevators have transformed the way people travel up and down in buildings. Today, traveling through a building using an escalator or an elevator has become second nature.  Circulation elements in buildings Corridors Portals (e.g. entrance, door, gate) Physical or Architectural elements Stairways Ramps Elevators Escalators Mechanical or Engineering elements Moving walkways  Elevators Elevators are mechanical lifts that provide vertical transportation for people and goods within a building. They operate through the use of an electric motor, which drives a system of traction cables and counterweights. When the motor runs, it pulls the elevator up, and when it stops, gravity takes hold, and the elevator goes down. Elevators come in different types, including passenger elevators, freight elevators, hydraulic elevators, home elevators, hospital elevators, and many more. Each type is designed to meet specific user needs. For instance, passenger elevators are used in office buildings, apartments, and hotels, while hospital elevators are designed to transport patients on stretchers and wheelchairs. Overall, elevators are a safe and convenient way to transport people and goods within a building. What is the difference between lift and elevator? The differences between lift and elevator are: 1- The terms “lift” and “elevator” are often used interchangeably, but there is a slight difference between the two. A lift is a general term for any device that moves people or goods vertically. An elevator is a specific type of lift that is powered by electricity. 2- Elevator is an American term, and lift is a British term.  Two major elevator designs Push Vs Pull Pull = Traction Push = Hydraulic There are two major elevator designs in use today: 1. Hydraulic elevators. 2. Traction roped elevators. 1 Hydraulic Elevators Hydraulic elevator systems lift a car using a hydraulic piston mounted inside a cylinder and driven by pressurized oil through a pump and valve system. The cylinder is connected to a fluid- pumping system. The hydraulic system has three parts: A tank (the fluid reservoir) A pump, powered by an electric motor A valve between the cylinder and the reservoir. The pump forces fluid from the tank into a pipe leading to the cylinder. When the valve is opened, the pressurized fluid will take the path of least resistance and return to the fluid reservoir. But when the valve is closed, the pressurized fluid has nowhere to go except into the cylinder. As the fluid collects in the cylinder, it pushes the piston up, lifting the elevator car. When the car approaches the correct floor, the control system sends a signal to the electric motor to gradually shut off the pump. With the pump off, there is no more fluid flowing into the cylinder, but the fluid that is already in the cylinder cannot escape (it can't flow backward through the pump, and the valve is still closed). The piston rests on the fluid, and the car stays where it is. To lower the car, the elevator control system sends a signal to the valve. The valve is operated electrically by a basic solenoid switch. When the solenoid opens the valve, the fluid that has collected in the cylinder can flow out into the fluid reservoir. The weight of the car and the cargo pushes down on the piston, which drives the fluid into the reservoir. The car gradually descends. To stop the car at a lower floor, the control system closes the valve again. Thus the system only uses power through the motor for upward movement and gravitational force for downward movement. Hydraulic Elevators 2 Traction Elevators The most popular & efficient elevator design is the roped elevator. In roped elevators, the car is raised and lowered by traction steel ropes. The ropes are attached to the elevator car, and looped around a sheave. A sheave is just a pulley with grooves around the circumference. The sheave grips the hoist ropes, so when you rotate the sheave, the ropes move too. The sheave is connected to an electric motor through a gear box. When the motor turns one way, the sheave raises the elevator; when the motor turns the other way, the sheave lowers the elevator. In gearless elevators, the motor is directly connected to the sheave and movement is controlled very precisely by movements of the motor. Typically, the sheave, the motor and the control system are all housed in a machine room above the elevator shaft. The purpose of this balance is to conserve energy. With equal loads on each side of the sheave, it only takes a little bit of force to tip the balance one way or the other. Basically, the motor only has to overcome friction -- the weight on the other side does most of the work. To put it another way, the balance maintains a near constant potential energy level in the system as a whole. Using up the potential energy in the elevator car (letting it descend to the ground) builds up the potential energy in the weight (the weight rises to the top of the shaft). The same thing happens in reverse when the elevator goes up. The system is just like a see-saw that has an equally heavy kid on each end. Both the elevator car and the counterweight ride on guide rails along the sides of the elevator shaft. The rails keep the car and counterweight from swaying back and forth, and they also work with the safety system to stop the car in an emergency. Roped elevators are much more versatile than hydraulic elevators, as well as more efficient. Traction Elevators  Escalators Escalators are the necessary “moving stairs” that carry people up and down between levels of a building. They are designed in a way where the stairs move in a cycle on a pair of tracks. The escalator consists of a motor-driven chain that moves the steps up and down. It’s interesting to note that escalators are power guzzlers as they have to operate continuously while elevators save electricity by consuming only when in operation. Types of escalators include parallel, crisscross, spiral, and inclined. These types of escalators have different functionalities and designs depending on where they are used. 1- Parallel escalators are designed for wider spaces such as malls and airports. 2- Spiral escalators are perfect for smaller spaces 3- Inclined escalators are ideal for outdoor spaces where most people are walking or standing. Advantages of using escalators: 1- Escalators are perfect for malls, metro and railway stations as they can carry more than 20 people at one time. 2- Patients and luggage cannot travel on escalators. 3- Escalators don’t require a specific machine room to control the system of escalator, while elevators require a specific machine room to control the elevator. Crisscross/ Parallel escalators Multiple Parallel Escalator Criss-Cross Escalator Single Parallel Escalator Continuous Linear Escalator SPIRAL ESCALATORS INCLINED ESCALATORS The component of Escalator Comparison between Elevator and Escalator Elevator and Escalator are integral parts of modern-day architecture. They are used to move people and goods vertically inside buildings. However, there are some vital differences between elevator escalator, and below we address them in depth. 1- Functionality 2- Design 3- Usage 4- Energy Consumption  Elevator Escalator Enclosed cabins that transport people and Consist of a motor-driven chain fixed on an Functionality goods up and down between levels of a individual track that cycles on a pair of tracks, building. They work on the principle of carrying people up or down the building counterweights and traction cables 1- Come with endless designs, including 1- Designed as diagonal stairs with an incline, Design cab size, door operation, and fixtures. and their structure is exposed, making them Depending on the intended use easier to access and operate. 2- Elevator can hold a maximum of 10-15 2- More than 20 people at one time people at once 1- Used in multi-story buildings like 1- Common in public spaces such as railway Usage apartments, banks, and offices stations, malls, airports 2- Offer privacy in terms of being in an 2- Offer open exposure to the surrounding enclosed cabin environment 1- Elevators consume less power 1- Escalator has to operate continuously, compared to the escalators. An elevator’s which accounts for higher energy Energy electricity consumption is only during its consumption operation 2- Do not have an emergency power backup Consumption 2- Having an emergency power backup  Elevator and Escalator Maintenance Maintenance is a crucial aspect of ensuring that lift and escalator continue to operate at their best, and it’s essential that this be carried out regularly. Proper maintenance ensures not only the safety but also the durability of the elevator and escalator, which is critical, considering the number of people using them each day. There are different types of maintenance required for lift and escalator: 1- Preventive maintenance is carried out to prevent breakdowns. 2- corrective maintenance is done after a failure has occurred. 3- Routine maintenance is necessary to ensure that the equipment is always in good working order. Frequency of maintenance depends on the usage of the elevator and escalator. High traffic areas require more routine maintenance than low traffic areas. A routine maintenance schedule should include regular checks of the electrical and mechanical equipment, cleaning, and lubrication.  Advantages of using elevators over stairs and escalators  Elevators provide convenience and accessibility, especially for individuals with mobility challenges or heavy luggage. They can transport more people at once than stairs or escalators, increasing efficiency in high-rise buildings.  Elevators eliminate the physical effort required to climb stairs, making them suitable for people of all ages and physical abilities. What are the safety considerations associated with elevators, escalators, and stairs? All are equipped with safety features to ensure the well-being of users: Elevators have various safety mechanisms, such as door sensors, emergency stop buttons, and backup power systems, to prevent accidents and ensure passenger safety. Escalators have safety features like handrails, comb plates to prevent entrapment, and sensors to detect obstructions and automatically stop the escalator. Stairs should be designed with proper handrails, non-slip surfaces, and adequate lighting to minimize the risk of falls or accidents.