REGULATING LIFT AND ESCALATOR SAFETY IN HONG KONG
Kim Ching Cheung, Yiu Hung Pang, Chun Fai Lai and Graham Lui
Electrical and Mechanical Services Department, HKSAR Government HKSAR
Quality and safe lift and escalator services are vital for a densely populated city dominated by high-rise buildings as in Hong Kong. The Electrical and Mechanical Services Department (“EMSD”) of the HKSAR Government is responsible for regulating the safety of lifts and escalators in Hong Kong by enforcing the Lifts and Escalators Ordinance through various means, such as conducting risk-based audit inspections, carrying out prosecution and disciplinary proceedings, implementing codes of practice as well as the registration of contractors, engineers and workers. EMSD has also rolled out various initiatives to facilitate the sustainable development of the lift and escalator trade, including maintenance price survey for lifts, performance ratings of registered contractors, collaboration with the trade and training institutes to recruit new blood etc. In addition, EMSD promotes lift and escalator safety to the public via diversified publicity and education programs. This paper will examine the ways on how EMSD plays its role as “Facilitator” and “Promoter” in addition to its traditional role as a “Regulator” on regulation of lift and escalator safety in Hong Kong, and the outcomes of its efforts.
HISTORY OF THE SAFETY GEAR
LECS UK LTD / University of Northampton United Kingdom
The safety gear is regarded as the last line of defence in the relatively safe world of lifts. Industry contemporaries recall Elisha Otis declaring “All safe” after cutting the ropes on a platform upon which he was standing and the safety gear preventing his uncontrolled descent. The design of safety gears has moved on significantly from an original proposal to place a bag of feathers in the lift pit to designs that now arrest uncontrolled movement in ascent. This paper is a developing research project which will look at UK patents and standards and tracks the development of the safety gear from the embryonic days of lift installations to the present day.
DUAL RATED SPEEDS ESCALATOR WITH AUTOMATIC SWITCHING FUNCTION IN RAPID TRANSIT STATIONS
Kong Cheong Gan, Linfan Cai, Sek Cheong Cheah, Hadi Wijaya and Melvyn Thong
Land Transport Authority of Singapore, Singapore
Rapid transit system is the main mode of public transport in Singapore. The escalators at rapid transit stations are usually utilized heavily to bring in and discharge large amount of passengers efficiently and safely. Currently, all escalators are designed and operated at the rated speed of 0.75m/s to meet the high travel demands during morning and evening peak.
In recent years, due to the ageing population in Singapore, our statistics have revealed that increasing escalator incidents in rapid transit stations are associated with elderly passengers due to their reduced reaction time and poor understanding of proper use of escalators. Surveys conducted have also shown that elderly passengers are more comfortable with the slower speed escalators. In order to accommodate the elderly passengers during off-peak hours while the high throughput (primary rated speed of 0.75m/s) is not required, a secondary rated speed of 0.50m/s is incorporated to operate the escalators during off-peak hours. Conventionally, switching between 2 rated speeds can be done either manually through key switch or automatically when no passengers on escalators are detected at pre-set timing. Leveraging on new technology, smooth and gradual acceleration and deceleration of escalator are achievable with more precise digital control for automatic switching safely while the passengers are still riding on the escalator.
The purpose of this paper is to present the concept and philosophy behind the approach and share the design, implementation, technical challenges and results for the development of the first in the world automatic seamless switching between primary and secondary rated speeds with the passengers riding on the escalator based on a scheduled timetable.
SYSTEMS ENGINEERING APPROACH: POSTGRADUATE PROGRAMME BRIDGING THE GAP BETWEEN THE THEORY AND INDUSTRIAL PRACTICE IN LIFT (ELEVATOR) ENGINEERING
Stefan Kaczmarczyk and Rory Smith
University of Northampton United Kingdom
The paper provides a comprehensive introduction to, and an appraisal of, a postgraduate Lift Engineering programme. The programme is based on Systems Engineering approach and has been designed to transfer the underpinning knowledge required for effective advanced engineering design, research and management in the lift (elevator) making and allied industries. The provision evolved from the distance learning provision which was originally developed following the introduction of the first edition of the European standard EN 81-1:1977. Some parts of the programme have been modified appropriately to reflect other national codes such as ASME/ANSI A17.1. The programme comprises the Masters - level course. The research degree programme offers then an opportunity for successful candidates to study towards PhD / MPhil. A technical case study is discussed to illustrate how research-informed learning aids the solution of complex Lift Engineering design problems. The analysis demonstrates how practice, learning and research are integrated into the programme.
THE DYNAMIC INTERACTIONS IN HIGH-RISE VERTICAL TRANSPORTATION SYSTEMS
University of Northampton United Kingdom
High speed and high capacity vertical transportation (VT) installations in the modern built environment service buildings of nearly 1000 m tall. Tall buildings are susceptible to large sway motions when subjected to wind loading or earthquake excitations. The low frequency sway motions cause resonance interactions in lift car/ counterweight suspension system, compensating ropes and overspeed governor ropes. This leads to poor ride quality and a high level of dynamic stresses which may result in damage to the installation. This paper presents the systems engineering approach to predict and quantify transient and steady-state resonant vibrations taking place in high-rise lift applications The results and conclusions presented in the paper demonstrate that a good understanding of the dynamic behaviour of VT systems is essential for developing design strategies that minimize the effects of adverse dynamic interaction so that the lift installation will operate without compromising the structural integrity and safety standards.
STUDY ON TRIBOLOGY PERFORMANCE OF SHORT CARBON FIBRE REINFORCED BRAKING MATERIAL FOR ULTRA-HIGH SPEED ELEVATOR
Yinge Li1, Xi Shi1 and Simo Makimallila2
1Shanghai Jiao Tong University China, 2KONE Finland
As a crucial brake component of the elevator, the braking performance of the safety gear is extremely important for the safety and reliability of the elevator. In this paper, an elevator safety gear braking testing rig was established based on disc brake model in principles of energy equivalent and speed equivalent to simulate the actual ultra-high speed braking working condition. Also friction wear properties of short carbon fiber reinforced material PC70 for high-speed elevator were investigated. Note that the braking pressure and the braking initial speed are controlled between 15Mpa to 30Mpa and 3m/s to 14m/s respectively in the experiment to provide ultra-high speed. The dependence of the friction coefficient on the p-v value was minutely studied, which is a transcendence compared to the previous research method under single working condition, letting the friction characteristics of the material under the corresponding working conditions be shown more completely. Besides, SEM analysis of wear scar were done to investigate the wear condition of braking materials under different working conditions. In general, this paper studied the tribology performance and the wear mechanism of ultra-high speed elevator, and explored the main failure modes and mechanisms of braking materials under different working and external conditions.
LIFT PLANNING FOR HIGH-RISE BUILDINGS
Peters Research Ltd UK
This paper provides an overview of the different ways of providing lift service to high rise buildings. In general, taller building need a greater proportion of core space to accommodate the lifts. To reduce core space, often the first option considered is to divide the lifts into two or more zones. Double deck lifts, with two cabs serving adjacent floors at the same time, provide greater handing capacity per shaft. Solutions with two independently roped cars per shaft achieve a similar handling capacity boost, but with added flexibility. For super high-rise buildings, shuttle lifts expressing people to sky lobbies offer further savings in core space. Planned rope-less lifts solutions promise significantly more handling capacity per shaft, freeing mega high-rise buildings of the limits imposed by roped lifts. Often the solution chosen will adopt more than one strategy and technology. The pros and cons of different approaches are discussed, together with a core space analysis of alternative solutions for example buildings.
PEOPLE FLOW ANALYSIS IN ELEVATOR MODERNISATION
Marja-Liisa Siikonen1 and Janne Sorsa2
1KONE Corporation Finland, 2KONE Industrial Finland
The modernization and retrofitting of elevators in a large building has its unique challenges. Current trends in offices, such as flexible working times and workplaces, overpopulated office floors and increased communication requirements, can trigger the need for modernization, which aims at keeping the building competitive. In a typical case, heavy queuing and long waiting times occur during morning up-peak traffic. One solution to such a situation is to modernize conventional collective control to destination control. The requirements of an elevator modernization vary case by case according to the building type, the condition of equipment, complexity and the data available from the existing installation. This article describes four levels of people flow analysis according to the involvement needed to acquire data and to perform the analysis. The first level incorporates a comparison of the existing and the new control system by simulating them with default traffic assumptions. This level provides a rough estimate of improvements gained by changing the control system. The next step is to measure the performance times of the equipment. The analysis based on the realistic performance will more accurately project the performance of a new equipment. In the third level analysis, vertical people flow is recorded, for example, by an elevator monitoring system or a passenger counting method. In addition to the current people flow data, extensive site surveys further increase the accuracy and widen the analysis. Horizontal people flow can be used to analyze passenger walking routes and to propose, for example, the location of transportation devices or improved guidance. This article describes the methods behind the different levels of analysis and their benefits to customers, and can be used as a handbook for choosing the proper level for a particular modernization project.
ROBOTS, A NEW CLASS OF PASSENGER
The University of Northampton United States
Lifts are increasingly being called upon to transport robots between floors in multi story buildings. The robots that are presently available place special demands on lifts and these demands affect traffic handling. The special demands are explained and the impact of these demands on waiting time and transit time are reviewed using simulation.
EXPERIMENTAL INVESTIGATION OF FRICTION AND SLIP AT THE TRACTION INTERFACE OF ROPE AND SHEAVE
Xiaolong Ma and Shi Xi
Shanghai Jiao Tong University China
In an elevator hoisting system it is crucial to ensure an appropriate adherence between the traction sheave and the hoisting ropes. However, little experimental work has addressed rope and traction drive interaction, thus it is not well understood and need further study. In this paper, an exclusive testing rig was built to experimentally investigate the friction and slip at elevator traction interface under different traction conditions. The effect of pre-tension of rope is also discussed which indicates that the full slip occurs earlier and is greater under smaller pre-tension force. The experimental results indicated that slipping occurs at both ends of contact arc first, and then expands to the middle region gradually until the full slip along the sheave occurs. In addition, the full slip occurs earlier under lower rope pre-tension. Meanwhile, by setting similar boundary and loading conditions as in the experiments, the finite-element analysis (FEA) was performed. The simulation results agree with the experiments very well but reveal more details about traction behavior. Finally, the distributions of contact pressure and rope tension along the wrap angle are utilized to indicate the slip condition during traction.
LONGITUDINAL COUPLED VIBRATION OF PARALLEL HOISTING SYSTEM WITH TENSION BALANCE DEVICES
Cao Guohua, Wang Lei and Yan Lu
China University of Mining and Technology China
In long-distance traction system, multiple parallel ropes are connected to conveyance through a set of termination device to achieve lifting process. Due to external excitations coming from different wear level and manufacturing error of rope grooves on friction pulley, or rope slipping, each rope length is distinct and accordingly resulting in different rope tension. Therefore, tension balance device is applied as the termination device to reduce the tension differences. In order to describe the dynamic behavior, rope sockets of the tension balance device are simplified into a lumped mass at the end of each rope, and longitudinal vibration model of parallel hoisting system with tension balance device is built. Both the normal and unsteady working conditions of tension balance device are considered. To deal with the complex constraints between ropes and hoisting conveyance, Lagrange multipliers are used, and the equations are numerically solved. The characteristics of longitudinal vibration frequency are depicted and the dynamic behaviors are revealed, which are essential for optimizing parallel hoisting system with the tension balance device. That will minimize the effects of external excitations and improve the security of the system.
STRESS ANALYSIS OF CRANE BEAM SYSTEM FOR LARGE TONNAGE ELEVATOR
Xiaomei Jiang Changshu1,Lanzhong Guo1 and Haijun Du2
1Changshu Institute of Technology, Jiangsu Key Laboratory of Elevator Intelligent Safety China
2Dongnan Elevator Co., Ltd. China
With the development of social economy and industry, people's demands for automation, batch production and high efficiency become higher which also stimulate the development of elevator industry. Some kinds of elevators have higher requirements for carrying capacity and safety, so the large tonnage elevator came into being in large manufacture factories. The distance between the supporting points of the crane beam stays wider. During the elevator's operation, the deformation and the stress of the crane beam are larger, so a reasonable crane beam structure system is needed. Design of large tonnage elevator is beyond the conventional standard of professional design, normally has to meet some special requirements according to the requirements of customers. In this paper, the layout and the stress analysis of the crane beam system for traction machine of large tonnage elevator, as well as the corresponding finite element analysis of important load-bearing parts were performed and the checks also carried on, finally the design and material selection of the crane beam system are determined and practically applied.
DYNAMIC BEHAVIOR OF TRACTION SYSTEM WITH TENSION AT THE PULLEY OF COMPENSATING ROPE
Lei Wang and Guohua Cao
China University of Mining and Technology China
With high capacity and low cost, the traction system is used in various lifting fields. Caused by the effect of hoisting and compensation rope with time varying, the natural frequency of the system is varying moderately during the period of operation. With the increasing of the lifting speed, the extrinsic motivation may cause resonance interactions in lifting system because of the intersection between the excitation and the natural frequency of the system. The dynamic model of the traction system with compensating rope is established based on Lagrange equations. The compensating rope is tensioned by a pulley with external force working on it. The characteristics of the natural frequency and the resonance response can be obtained through different tensioning methods, which can provide reference for the design of long distance and high speed hoisting system.
THE STUDY OF HOISTING SYSTEM FOR VERTICAL SHAFT CONSTRUCTION WITHOUT THE PROTECTION OF GUIDED-CABLE
Naige Wang, Guohua Cao and Yan Lu
School of Mechatronic Engineering, China University of Mining and Technology China
The sinking bucket, known as the hoisting conveyance of the system, is used to transport the waste pile, water, mine diggers and sinking equipment. In the case of construction shaft when it through the sinking platform, the bucket segregated from guided carriage and descends or increases for free without the protection of guided-cable. The abnormal condition is a common phenomenon during mine vertical shaft. The hoisting rope is a flexible wire with a low damping, so it is easy to cause oscillating resonance. This study is concerned with the theoretical modelling and simulation verification of the oscillating resonance of sinking bucket and hoisting rope. A large transient amplitude and steady state oscillations of the payload may occur inherently which is dangerous. It will threaten the safety of the miner diggers' lives and delay the process of construction of vertical shaft. Thus, the research on the dynamic characteristics of the sinking bucket without the protection of guided-cable are necessary.
COUPLED VIBRATION OF ROPE-GUIDED HOISTING SYSTEM UNDER MULTI-BOUNDARY CONTRAINTS
Yan Lu China and Cao Guohua
University of Mining and Technology China
In addition to being used as hoisting ropes, wire ropes are also used as guiding rails to provide guidance for hoisting conveyances in many Chinese hoisting systems of more than 1000m shaft and outdoor long-distance lifting systems. Different from high-frequency vibration of the system with rigid rails, rope-guided system vibrations are characterized by lower-frequency vibrations and greater amplitudes. Little researches are publicized for rope-guided system, especially under the constraint of multiple rope guides. More complicated dynamic characteristics will appear due to the mutual restraint between hoisting conveyance and each rope guide, which are important for safety and stability of working conveyances.
Therefore, modeling for coupled vibration of time-varying hoisting system with four rope guides is presented by energy method in this paper and the system vibration equation is established with Lagrange multiplier method. The analysis presented in the paper demonstrates how tension and density differences between rope guides and the hoisting rope eccentricity affect the amplitude of lateral and torsional coupling vibration as well as the position of torsion center. These characteristics provide guidelines for the design of double conveyances hoisting system to prevent conveyances collision and lay a foundation for future research.