29 replies to this topic

[highspeedquad]

Is it possible to change the capacity of a lift either higher or lower besides speeding up the lift and adding carriers (is possible). I was just wondering because there are some six-packs that have capacities of 3000 pph and those that have 3600 pph and if it would be possible to boost the capacity for lifts with a current capacity lower than the design capacity.

[edmontonguy]

Capacity Depends on Chair spacing intervals. The only way i know to decrease that interval is by adding chairs or speeding up the lift.

[Zage]

Well, speed is the main factor in lift capacities(I think) but for a higher download capacity, adding more sheaves gets the job done. And I think increasing the speed in the terminal(if it is possible) that would do it. John or Cameron can confirm or deny.

[Allan]

If the lift is designed for a higher capacity and only needs carriers added to do so, then yes, it's possible. Inreasing the speed will change the capacity, but not to the degree of adding carriers, as most people run the lift at its design speed. However, those six-packs you mention, their design capacity may only be 3000 pph. A lift's capacity is determined by a number of things, such as (but not limited to): length, sheave/tower loading, tension force, speed, number of carriers, number of people on a carrier, motor HP, etc.

[highspeedquad]

So some lifts may be able to increase capacity but some may not? Like the Super Bee at Copper, it has a capacity of 2900 pph. They would not be able to upgrade it if it was only designed with a capacity of 2900 pph?

Also, if both the intervals were 6 seconds, why would one lift have more and the other have less capacity? It doesn't make sense. Does it have to do with the spacing on the line and the speed?

This post has been edited by highspeedquad: 23 February 2005 - 03:16 PM

[Allan]

That's right, if the lift's design capacity is 2900 pph, then that's it (without re-engineering, if it's even possible). If two lifts have 6s intervals, then yes it's a carrier spacing & line speed thing. If one lift runs at 2.5 m/s and has 15m carrier spacing, while another runs at 3.0 m/s and has 20m spacing - then the intervals would both be about 6 seconds.

[highspeedquad]

So if someone wanted to change the capacity of the lift that was at design capacity then they might have to bring in people who could do that and work on some of the mechanics in the terminals?

What about fixed grips? Are you stuck at the design capacity no matter what?

[Allan]

It depends, it usually isn't feasible, as it could require adding towers, changing sheave assemblies, a new counterweight, or changing the specs on the hydraulic tensioning units. The prime & auxiliary movers may need to be replaced for a higher horsepower units, the gearbox may need to be changed for the higher HP coming into it, the service brake for the additional loads - the list goes on and on. Same goes for Fixed grips. HS lifts would need their cadencing parameters changed, the zone switches would have to be modified to allow for more carriers in a given zone. As well as all the stuff I mentioned above.

[highspeedquad]

So pretty much it would take a lot more effort than its worth. I guess its only easily possible if you aren't running it at it's design capacity. Otherwise, you're out of luck.

[Allan]

Exactly If you just have to add carriers, then it's easy!

[liftmech]

B-lift could run a higher capacityif 1) we added more carriers 2)changed the speed of parts of the tyre banks 3) upgraded the drive, electric motors, and aux engines. The Flyer could be done simply by adding more carriers and speeding up the chains to decrease the spacing. Both lifts would have to have their brake adjusted. I have my brakes set to 'initial capacity' but there's a section in the manual stating the 'final'capacity, which is 2800 as opposed to the current 2400.

Loading interval is directly related to line speed. A fixed-grip operating at 500 FPM and with 50' chair spacing will have a six-second load interval. A detachable running at 1000 FPM and with 100' spacing will also have a six-second load interval. If you have a five-second interval, then you end up moving every chair forward 16.667 feet. That would allow you to add 44 carriers on a lift the size of the Flyer, which has 203 carriers.

[Duck]

An easy way to think of it:

Time the interval between chairs. To get a higher capacity your interval has to be less. You can decrease that interval by a ) adding chairs or b ) speeding up the rope.

Ultimately the defining factor on capacity is interval and capacity per carrier.

This is why a compact coaster running all 3 trains on a busy day, at 12 passengers per train, can have the same capacity as say, a big B+M hyper running just 1 train on a slow day, that holds 36 passengers.

(and all the B+M hypers have 3, 36 passenger trains. ;))

A fixed grip chairlift can have the exact same capacity as a detachable, if the time interval between chairs is the same. Assuming the rope speed is significantly faster on the detachable, though, the spacing (pitch) on the ropeway would be greater. But of course the travel time to the top will be much reduced on the detachable because of the higher rope speed.

-Iain

This post has been edited by Duck: 24 February 2005 - 05:55 AM

[highspeedquad]

Liftmech, are you saying that the Super Bee is not rinnung at design capacity, or would you have to do some reengineering?

[liftmech]

That's not what I said; I merely stated what we'd have to do if we wanted to increase capacity. It is currently running at design capacity; remember it replaced two doubles so anything is a step up. The lift rarely gets a line and when it does it's because someone fell on the top ramp and the lift had to stop. Once it gets going again it 'kills the maze' quickly.
I did say that the Flyer is not running at final capacity, but we're not going to take it to that point because it would never run well with 44 extra carriers. There are enough beginners crashing and burning on the ramp as it is

[Zage]

Here is a way to increase the capacity of a lift, ad a conveyor to the loading area.

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[highspeedquad]

But what would happen when you got to the top station? If you recalibrate it to a chair every 5 seconds then there might still be a chair in you way at the top.

[edmontonguy]

Under the bullwheel unloading will eliminate this problem. Usually due to the fact that after the chair is unloaded it immediatly goes around the bullwheel and back down the lift. Several quads i've been on are so good at this that if you're on the inside of the chair you have to be careful the chair doesn't whack you in the back of the head.

[WBSKI]

How did some of the old Yan HSQ's achieve such a high hourly capacity (2800) when they were runing at half the speed of a normal HSQ (only 500fpm)?

[Duck]

Closer chair spacing distance to acheive a similar time-interval between chairs, probably. If you've got a 4-wide chair every 6 seconds, it doesn't matter how fast the line speed is going, you're going to have the same capacity.

-Iain

[highspeedquad]

The only thing was that they would get up a little slower, but the same number of people would still get up.