Technical Analysis of Lifts - Coursework Example

Title Page -Running header: Technical Report on Lifts Student’s Name: Instructor’s Name: Course Code: Date of Submission: Technical Report on Lifts Introduction A lift or an elevator is a vertical vehicle that efficiently transport or moves people or goods between building floors. They are usually powered by motors that are electrically driven. These motors drive counterweight systems and traction cables. They are also used to pump hydraulic fluid that is used to raise a cylindrical piston. Elevators are legally required in all multi-storey buildings; this is especially where ramps for wheelchairs are impractical. Lifts began to be used a long time ago as chain hoists or simple rope. It was in the form of a platform that was pushed or pulled by mechanical means. This compares to modern lifts that have a cab or cage mounted on a platform. Lift drive mechanisms, initially used water, and steam hydraulic powered pistons. This report will describe how lifts work and give various examples as well as parameters involved in lifts. Lift history starts all the way from early 1160s. Manually operated elevators were used to lift goods in manufacturing plants and warehouses. A German Engineer Konrad Kyser was one of the oldest engineers to design an elevator in 1405. An elevator with screw lifting mechanism was created by Ivan Kulibin in 1793. On March 1857, first Otis passenger elevator was put in New York City at 488 Broadway. It included elevator shaft in its design. In 1880, Werner Von Siemens designed first electrical elevator. Its speed and safety were enhanced by Frank Sprague. A method that permitted doors of elevators to close and open safely was patented by J. W. Meaker in 1894. By 1882, there was a well established technology on hydraulic power lifts. The main reason that led to use and invention of lifts was to raise and lower loads to various floors. Table of Contents Title Page 1 Introduction 2 Table of Contents 3 Main Body 4 Working of a lift 4 Lift Parameters or Data 9 Requirements to Put a Lift in a Building 10 Graphics of a lift 10 Types of lifts-Advantages & disadvantages 12 Environmental impacts of a lift 14 Skyscrapers and lifts 15 Conclusion 15 Bibliography 17 Main Body Working of a lift According to Great Britain, Department of Trade and Industry, Standards and Technical Regulations Directorate (2000), working of a lift is not a complex process. When someone steps or gets into a lift car, the two doors closes. The current is supplied to the motor making the brake to release making the car to move. Elevator car is usually inside the lift shaft or vertical passageway. Inside the vertical passageway are hoisting cables that are attached at the top of the car. The cables are connected to an electric motor through a sheave or pulley at the top most part of the shaft. They are motors at the top that are connected to the car, these moves or lifts the car up and down using pulley system. The car has modular rail system where the car moves on. The rail system acts as a guide to the car as it moves vertically up. Lifts have electric motor that rotates making the cables and chains to move hence lifting the car. On the other end of cable is a heavy weight of steel called counterweight. The counterweight goes down when car moves up. When the car moves down, the counterweight moves up. Counterweight is mainly to reduce the power required to operate elevator to minimum in a motor. Weight of counterweight is usually equivalent to approximately half the maximum load of passengers and the weight of the car. Therefore, when elevator operates, it requires power to raise the load of extra people in the lift car. The rest of the load is then balanced by counterweight. There are two chains acts as connector between the car and the counterweight. Counterweight increases the forces that are ascending while decreasing acceleration forces that are descending, this eventually reduces amount of required motor power. Use of counter weight helps in reducing power amounts used. It is more convincing way of assisting the car to move up and down. Car, pulley and counterweights are the main elements to the working of a lift. The movement of the car is enabled by the pulley system and counterweights. The pulley is connected to the motor at the top of the channel. The pulley is connected to the car through the cables or chains. The counterweights are also connected to the car through the cables. The counterweight is at the bottom of the channel. The pulley moves the car up as the chains and cables winds themselves in the pulley. The movement and rotation of the motor and the pulley system is enabled by the control system in the lift system and control switches inside the car. This movement is also facilitated by counterweight that adds extra force enabling the car move up without motor applying much power; it increases the forces that are ascending. As the car moves down, the chains unwind themselves in the pulley system. This enables the car to move down with counterweights decreasing acceleration forces that are descending. The counterweight moves up as the car moves down. Lift has several controls that enables to the lift to move up and down. When the car starts moving up, the control system ensures the lift stops at the required floor. This is through sending of a signal that makes the floor selector magnet assembly to stop at the required floor. The selector magnet assembly is a set of magnets and control system. It is connected is such a way that, it makes the car stop at the selected floor. Other controls include 115 and 230 volt auxiliary disconnects that also assist the movement of the car along the rails. When the car reaches the required floor, the control stops the car through the magnet assembly. A motor armature that is short-circuited makes the car stop as it reaches the correct floor through circuit contacts. This is through the contactor circuit that is broken using floor selector that de-energizes all coils at once making the car stop at one time. Circuit contacts assist and ensure the lifts stop at the right position or floor. According to How-stuff-works Inc. (2004), braking system in a lift has routine braking system and other emergency braking system. It has a safety as shown in below diagram making them cramp on steel rails notches stopping it. A graphical appearance of a lift mechanism for braking system The speed upon which the car moves is controlled by use of speed frequency controlled variable machine, this has a counter weighted chain drive. For the car to start moving, the controls send signals to various control areas. This starts the movement or the stopping of the car. A graphical appearance of a lift mechanism for electrical driven lift The lift below is a hydraulic system. It uses hydraulic fluid instead of electric. It has no magnet system for stopping the lift; instead it utilizes the hydraulic mechanism for stopping and moving. It has counterweights like the electrical lift. It has controls that send signals of various operations required. A graphical appearance of a lift mechanism for hydraulic driven lift Lift Parameters or Data Lifts are usually driven by two systems. They include hydraulic drive and electric traction drive. In determining which of the two is suitable, they are several factors that need to be taken into consideration. Some of these factors include height of the building, frequency of use, number of floors, number of people to be transported and desired waiting times for passengers. According to Great Britain, Department of Trade and Industry, Standards and Technical Regulations Directorate (2000), there are several parameters that are used when designing and installing lifts. A passenger elevator is designed in order to move people from one floor to another in a building. The capacity of a passenger elevator is usually related to floor space that is available. Passenger elevators are manufactured in ranging capacities ranging from 450Kg or 1000 pounds to 2700 Kg or 6000 pounds. They have an increment of 230 kg or 500 lb. in buildings that have eight floors or less, they may be either electrical or hydraulic. The passenger elevator can go up to a speed of 1m/sec (200ft/min) in case of hydraulic one. Hydraulic passenger elevators reach a speed of up to 500 feet/ minute. Electrical elevators begin at 2.5 m/s (500ft/min) to a maximum of 10m/s (2000ft/min). Freight elevators are large and have the capability of carrying 2300 to 4500kg; they are designed to carry heavy loads. A lift should have a landing space that is unobstructed; it should be at least 1500mm by 1500mm. The doors should give a clear opening width of 900mm; the minimum should be 800mm. Height, width, and length should at least be 2300mm, 2000mm and 1400mm respectively. Lift should also be designed in such a way that, landing controls should not be less than 900mm or more than 1200mm from floor level. Car controls should not be less than 900mm or more than 1200mm from floor level. Requirements to Put a Lift in a Building Fred & Roger (2009) maintain that, it is essential for builders to take into consideration the building regulation. It is also important to take into consideration the requirements of placing a lift in a building. Any building being constructed should have adequate space of putting a lift. Another very vital requirement in any building is to take into consideration the needs of a physically disabled people. The lift should take the safety issue into consideration. It is supposed to be easily reachable to everybody in spite of physical condition. Lift should have accessible switches and clear signals identifying all the parameters of where about. Graphics of a lift Some of the controls used inside the car When one gets into a lift, one presses the switch depending on which floor he is going. There are usually placed near the doors where they are accessible. Other switches include bell button, door opening switches among others. There are also signals indicating the direction of movement and exact position it is in. Typical elevator at the door This is the main door of the car, it usually of a sliding type. There are also switches of opening the doors. Others are signals that indicate the place where the lift is, they also show the direction which the lift is moving. Modern lift-it is usually referred to as observation elevator; it is usually used in very tall building with many floors. This has glass on the side which provides a clear view of the outside. Types of lifts-Advantages & disadvantages Davis (2005) argues that there are two main types of lift drive system that are available. They include hydraulic and electrical drive. Every type has disadvantages and advantages related with it. Electric traction lifts can be categorized into machine room-less (MRL) lift. The driver motor is usually mounted within shaft; other controls are placed near door housing. This eliminates the need of having a separate room. This type of lift has car dimensions flexibility; it utilizes to maximum the shaft in carrying volumes that are large. Another electric traction lift is one with machine room (MR). It is located either on top, bottom or on one side of the lift shaft. Geared traction systems are mainly used where applications have high rated loads as well as lower speeds. Electrical traction lifts supply or gives high output; they perform highly. They do not require frequent maintenance like adjustments or lubrication. Variable frequency controllers give acceleration that is smooth with good braking system. This improves passengers comfort as well as precise car leveling at floor. Another main advantage of electric powered elevators is that, electricity is universally available in many buildings. Electrical elevators have a simple cable and pulley system; this makes them to have no limit in terms of height. They can rise up to any level in any building. They also move at a very high speed of up to 153m/min (500 feet/ min). Some modern elevators have motors that make them move at a speed of up to 610m/min (2000feet/min). They have a quality ride than the hydraulic ones. They use no oil like the case of hydraulic lifts. However, electrical lifts use a lot of power in their operation. Hydraulic lifts use the principle of pressure transfer from one cylinder to another. It uses pistons and cylinder in its operation. Hydraulic lift is advantageous because the force can be multiplied from low forces to generation of high forces. This can eventually lift heavy loads or people in the car. They are applied where heavy loads are being lifted. The machine room location is relatively flexible; it can be any distance of up to 15 meters away. However, they are several disadvantages associated with hydraulic lifts. Hydraulic lifts do not reach high floors like in the case of electrical lifts. In order to make them reach high floors, one has to incorporate longer pistons and cylinders. This means that, since the piston has to go all the way to the bottom, then the cylinder housing has to be buried below the building. It has to be as the same length as the height as the building itself. Hydraulic lifts are inefficient. Raising a car elevator, several stories use a lot of energy. Nonetheless, there is no where to store this potential energy. This energy is used to push fluid back to the reservoir. Therefore, when raising it again, the system has to generate energy again. A lot of repairs are needed due to hydraulic system. Hydraulic oil need to be replaced after sometimes, this will avoid failure at any moment. They usually move at a low speed compared to electrical ones. Other categories of elevators are freight elevators, vehicle elevators, passenger elevators and boat elevators. Others are residential elevators, limited application elevator, paternoster, scissor lift and rack and pinion lift. These may either fall in electrical or hydraulic type of lift. Vehicle elevators are used in buildings with limited space so as to move cars to parking lots. Geared hydraulic chains are usually used to generate platform lift; this lifts the cars to the required height. Freight elevators are used to lift goods. They are electrical type of elevators; this is due to high power needed and high energy efficient of hydraulic elevators. They are designed to lift very heavy loads. Passenger elevator is the most familiar category of elevator. Its main purpose is to move people from one floor of a building to the other. Aircraft elevators are used to carry aircraft between hanger deck and flight deck for repairs. They are usually designed for higher capacity than other elevators. They can handle up to a capacity of 90000kg (200000pounds) of aircraft and equipment. Residential lifts are less complex and costly compared to full commercial elevators. They are used for home suiting. Limited application elevator is an unusual passenger lift; it is usually used infrequently. Dumbwaiter is a small elevator used to carry food and not passengers. They link rooms with kitchen when they are at different floors. Other type of elevator is a double deck elevator. Its manufacturing is such a way that it has two elevator cars. One is attached on top of another, hence passengers on two consecutive floors, can access at the same instance. It is beneficial since it increases the capacity of passengers on lift. Double Deck elevator at C.D. Howe Building in Ontario, Canada Environmental impacts of a lift The waste that comes from disposing old lifts are hazardous and of great concern. All lift manufacturing companies should adhere to the environmental regulation act. This is to ensure that no hazardous waste materials are disposed to the environment after its disposal. Skyscrapers and lifts According to Emporis.com (2009), one of the tallest skyscrapers in the world is Taipei 101 in Taiwan. Its lifts are fastest in the world. They rise up to 1080 meters per minute. It has double deck elevators. They also have emergency braking system. Conclusion Lifts have small rooms referred as cars where people get into and move in it. The cars move through a channel referred as lift shaft or vertical passageway. The vertical passageway has hoisting cables attached at the top of the car. These cables are connected to an electric motor at the top most part of the shaft. They move or lift the car up and down using pulley system. Lifts have a Counterweight system, this is mainly used to reduce the power required to operate elevator to minimum in a motor. Two chains connect the car and the counterweight. The floor selector magnet assembly is used to stop the car at the required floor through the use of signals and a motor armature that is short circuited. Lifts are usually driven by two systems that include hydraulic drive and electric traction drive. They are several factors that need to be taken into consideration when deciding the type of lift to use, they include height of the building, frequency of use, number of floors, and number of people. All buildings should have adequate space of putting a lift while taking into consideration the needs of a physically disabled people. Lifts are broadly classified as hydraulic and electrical driven. However, they are other categories depending on size. They include freight elevators, vehicle elevators, passenger elevators and boat elevators. Lifts impose a threat to the environment. This is due to hazardous waste materials are disposed to the environment after its disposal. The tallest lifts are found in a sky scraper called Taipei 101 in Taiwan. Lifts are of great significance in helping the society or people to get into the top of the building. There is the need to modernize lift installation so as to ensure reliability and effectiveness. In order to minimize maintenance cost, unreliable components due to age and use should be replaced. It is important to use the lift according to its intended purpose it was manufactured for. Lifts vary in size and even intended purpose leading to a variety of lifts that are in use today. Lifts have evolved for many years up to now when there are modern ones that more effective in their use. Lifts should be used for the intended purpose it was manufactured for to avoid the accident and failure as a result of misuse. Bibliography Davis, L 2005, Lifts and escalators. Building sustainable design, United Business Media, Viewed 25 March 2010, Emporis.com 2009, Taipei 101, Emporis, Viewed 25 March 2010, Fred, HK & Roger, GJ 2009, Building Services Handbook: Incorporating Current Building & Construction Regulations, 3rd edn, Butterworth-Heinemann: Michigan. Great Britain. Department of Trade and Industry. Standards and Technical Regulations Directorate, 2000, Lifts: UK approved bodies…as at 30 September 2000, 2nd edn, DTI, Michigan. How-stuff-works Inc. 2004. What if cable broke when you were on an elevator? 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Car, pulley and counterweights are the main elements to the working of a lift. The movement of the car is enabled by the pulley system and counterweights. The pulley is connected to the motor at the top of the channel. The pulley is connected to the car through the cables or chains. The counterweights are also connected to the car through the cables. The counterweight is at the bottom of the channel. The pulley moves the car up as the chains and cables winds themselves in the pulley. The movement and rotation of the motor and the pulley system is enabled by the control system in the lift system and control switches inside the car.

This movement is also facilitated by counterweight that adds extra force enabling the car move up without motor applying much power; it increases the forces that are ascending. As the car moves down, the chains unwind themselves in the pulley system. This enables the car to move down with counterweights decreasing acceleration forces that are descending. The counterweight moves up as the car moves down. Lift has several controls that enables to the lift to move up and down. When the car starts moving up, the control system ensures the lift stops at the required floor.

This is through sending of a signal that makes the floor selector magnet assembly to stop at the required floor. The selector magnet assembly is a set of magnets and control system. It is connected is such a way that, it makes the car stop at the selected floor. Other controls include 115 and 230 volt auxiliary disconnects that also assist the movement of the car along the rails. When the car reaches the required floor, the control stops the car through the magnet assembly. A motor armature that is short-circuited makes the car stop as it reaches the correct floor through circuit contacts.

This is through the contactor circuit that is broken using floor selector that de-energizes all coils at once making the car stop at one time. Circuit contacts assist and ensure the lifts stop at the right position or floor. According to How-stuff-works Inc. (2004), braking system in a lift has routine braking system and other emergency braking system. It has a safety as shown in below diagram making them cramp on steel rails notches stopping it. A graphical appearance of a lift mechanism for braking system The speed upon which the car moves is controlled by use of speed frequency controlled variable machine, this has a counter weighted chain drive.

For the car to start moving, the controls send signals to various control areas. This starts the movement or the stopping of the car. A graphical appearance of a lift mechanism for electrical driven lift The lift below is a hydraulic system. It uses hydraulic fluid instead of electric. It has no magnet system for stopping the lift; instead it utilizes the hydraulic mechanism for stopping and moving. It has counterweights like the electrical lift. It has controls that send signals of various operations required.

A graphical appearance of a lift mechanism for hydraulic driven lift Lift Parameters or Data Lifts are usually driven by two systems. They include hydraulic drive and electric traction drive. In determining which of the two is suitable, they are several factors that need to be taken into consideration. Some of these factors include height of the building, frequency of use, number of floors, number of people to be transported and desired waiting times for passengers. According to Great Britain, Department of Trade and Industry, Standards and Technical Regulations Directorate (2000), there are several parameters that are used when designing and installing lifts.

A passenger elevator is designed in order to move people from one floor to another in a building. The capacity of a passenger elevator is usually related to floor space that is available. Passenger elevators are manufactured in ranging capacities ranging from 450Kg or 1000 pounds to 2700 Kg or 6000 pounds.

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