Table of Contents
Lifts Explanation
These are the system used for vertical movement inside a building and comprises of one or more cars (sheet metal boxes with sliding doors), suspended during a structural ‘sling’ of metals channels, that will be moved up and down the storey’s of the building by some driving and controlling mechanism.In an easy installation, the lift shaft is of concrete or masonry forming the part of service core. And desirably the motor room is directly above the shaft.
Safely overruns are kept above the highest landing level and within the basement pit.
The counterweight balances the car weight and ensures that the hoist rope’s friction grips the also this reduces motor power consumption.
The motor caliber is employed to beat friction, acceleration, inertia and therefore the unbalanced load during lifting.
Hence the compensating cables are there to offset the load of the hoist cables, transferring to the counterweight side because the car rises, keeping the load on the sheaves balanced.
Slower lifts maybe driven by an AC motor but variable voltage DC motors provides a better, smoother performance for high speed lifts.
A lift motor room has following features
✓ A concrete machine base incorporating a vibration isolating cork slab to separate it’s upper and lower parts.
✓ Motor and brake equipment bolted to the upper, vibration-isolated, concrete slab.
✓ Flexible armored electric cable connection to the motor.
✓ The lift motor main isolator switch close to the plant room door.
✓ An access hatch into the lift shaft.
✓ the electric control panel
✓ A lifting beam built into the structure.
✓ Adequate artificial illumination
✓ Natural ventilation
✓ 13 an influence point
✓ Locked door
✓ Light colored walls and ceilings
The size, location and number of cars are selected pertaining following factors
Building size and type
Passenger lifts are provided for building of over 3 storeys, or less if wheelchair movement is required.
And the least standard of service is 1 lift for every 4 storeys and with a maximum walking distance of 45m between workstation and lift lobby.
The peak assertion lift service is assessed from the building size, shape, height and population. Up to 25% of the population would require transportation during a 5min peak period.
Fulfillment the peak travel times will be minimized by arranging the lift lobbies during a cul-de sac of, say, two lift doors on either side of a walkway, instead of during a line of 4 doors along one wall.
Car’s capacity
The lift’s carrying capacity is decided by the demand at peak times. And 2 lifts of 680 kg carrying capacity (10 people) provide a beller service than one 1360 kg, 20 person lift.
And the broad single lift will run only partly loaded during the main part of the day with a resulting decrease in efficiency and increased running cost.
But additional cost of capital for 2 lifts should be lower than the benefits of using it.
Car speed
It’s determined by travel distance and standard of service. that do and not standard slop at the of service. Buildings having quite 10 storeys may have high-speed lift that don’t stop at the first 10 storeys.
Car speed for various travel distances will be listed as
Floor Carspeed m/s
4 0.75
9 2
15 3
more 15 5-7
Car speed is chosen in order that the driving motor are often run at full speed for much of the running time to maximise the efficiency of power consumption.
And the all-up speed of performances is decided by the acceleration time, braking time, maximum speed of door opening, degree of advanced door opening; floor-leveling accuracy required; switch timing and variation of car performance with car load.
Control Mechanism
The automated system should function in an upward collecting and downward collection mode, computer controls are wont to optimize the overall performance of the installation by causing the closest car to prevent , and to reduce electricity consumption.
Classification of Lift
1. Passenger Lift
✓ The minimum size of lift cars shall be 13 persons (1400 mm widex 1600 mm deep car platform) for all passenger lifts no matter travel distance and number of floors served.
The lifts are to have provision for protective blankets altogether lift cars to safeguard their finishes.
Lift car finishes shall be or similar to the subsequent .
6wl Timex ‘licido’ on 6mm minimum backing with folds to side walls and lower half rear wall.
Remark that the lift car must have an outer shell. Backing timber or equiponderant of a minimum of 6mm then the car finishes applied to the limber lift car finishes must not be the metal lift car shell or attached on to the shell.
✓ Bump rails (bump rails shall be installed on each side and rear wall, hard wood timber estapol finish 150 mmx20 mm thick) just under the handrails and again 50 mm above the lift car floor.
✓ Aluminums framed laminated silver mirror to offset portions of side walls only indirectly opposite one another .
✓ Fixed white colored lamented lift car selling
✓ 38 mm dia. s/steel handrail security attached to side and rear wall.
✓ Lift car lighting, LED.
✓ car door and car front, finished stainless-steel
2. Good Lift
✓ Goods lifts shall have similar finishes with bump rails (bump rails shall be installed on each side and rear wall, and again 50mm above the lift car floor, hard wood umber estapol finish 300x20mm thick) and possible omission of the car mirrors.
✓ Goods lifts are to own appropriate finishes for the intended use as a minimum they have to be durable and simply cleaned.
✓ Goods lifts are to be sized and have features as needed for their particular applications and dosage. See section on Hazardous Goods Operation.
✓ Specialist good lifts for chemicals, animals; etc may require special finishes that has to be co-ordinate with the Project Manager Designer and user .