Greetings, thanks for reading any advice is greatly appreciated.

We're working on 2 hydros for a train station (new construction), eastbound and westbound.

Westbound lift has a noticable vibration on startup, no vibration going down.

Eastbound lift is running smoothly.

The only difference between the two elevators is the length of the hydraulic piping. Eastbound is around 20' and Westbound is around 65'.

Could the length of the pipe be the cause of the vibration?

Thanks
-Dennis

Could be air in the lines,plugged intake on the power unit,if its telescopic a piston could be hung up,most likely not the length in oil line unless its not secured

Could be pipe run length, but vibrates only in the up.

Isolation around feedline that penetrates floor or walls;
How does the motor/pump sound in the machine room?
Isolation at the piston to car? Isolation coupling in the feedline and a muffler?
Jammed feedline connection transmitting that harmonic pump vibe?

Is the ride spongy at all? Bouncing at slowdown points or final stops?

I notice they are belt drive. I had a bad sheave on a belt drive once that was out of balance. Replaced the sheave and it was gone. Try pulling the valves after starting the unit up, think low oil test, and see if vibration still exists with no oil going through the lines. If it's still there you have isolated it to the machine room at the very least.

Well, I suppose the OP is still working on his unit issue. It’ll be nice to hear what the outcome was.

Hello everybody,

I'm sorry for not responding, I was sent to a different location.

But I'm back and we are currently doing an inspection on said elevator.

The inspector noted the vibration problem, it has to be fixed.

Everybody, thank you for your responses, they will all be taken into consideration while we try to fix the problem.

I will keep you updated. Thanks again


Here are some more details:
Jack is not telescopic
Air was drained
Line is not isolated
Motor in machine room sounds perfectly fine
Isolation coupling yes, muffler no
Ride is not spongy/bouncy
I checked the belt, everything looks perfect
We did low oil test, no change

Noticed you said no muffler. I would start there.

My mistake, the muffler was preinstalled by Canton.

We opened the drop ceiling and checked the pipe for vibration, there was none. The problem isn't with the length of line.

Thanks for getting back Dennis,

Seems you’ve eliminated several possibilities, and NO PIPE VIBRATION. Did you check for piston to car isolation? Could it be the jack packing, or is down direction smooth in all transitions?
Poster “lowoil” suggested a clog at the pump intake...all ok there?

Are the mufflers the air up kind? You must air these up as it make a HUGE difference. Also you must air them up with no pressure on the system so manual lower the cars on the spring first.

Hello,

Here's an update.

There is piston to car isolation, it's unlikely that the problem is with the jack.

No vibration from motor room and it's a new installation, clog doesn't seem likely.

The mufflers are not the air up kind.

Somebody from my shop who specializes in hydros came to take a look and the solution was to install a second muffler. But an MTA inspector came and shut that down, he said the long island railroad doesnt want any extra parts on a new build.

I'll keep you posted
Thanks again for the replies

I would think that there is air in the jack. did you try bleeding it in the pit at the jack head?

One other thing to try is to salve the piston with that green goop to eliminate the packing.

Does this unit have slide guides and are the rails tight at the bottom landing? Does it have a soft start and is the valve picking before the motor is up to speed? Have you tried adding Cat oil additive?

Bummer about the muffler thing, but you’d never know it was the solution till you tried. Swap out the pump (even if it sounds ok) since the vibration is only in the up, nothing to loose there, and at least “you’re not adding parts”.

I’m anxious to hear the fix on this one.

....I had a unit that did the same thing after we changed packing tried adjust the valve the problem was in the tank unit after the pump and motor assembly was changed out..no more vibration...rides smooth..

I see you have a dry pump on this installation. It may seem like a simple thing but I've seen belts that are not tight enough feel like vibration in the car. The belts skip at a high rate and cause the pump to pulse. Did you confirm the belts are nice and tight?

S

And they have to be tighter then Banjo strings.

Hey everyone,

Quick update: We were approved to install the second muffler, it's the air up kind this time. Fingers crossed.

Hi Dennis,

I don't know if you've worked with those mufflers before, but it might be hard to get it up to pressure in the air bladder, most air compressors don't build enough pressure. If you have access to a tank of nitrogen it is the easiest way to do it.

S