Scraper failure
Scraper failure
(OP)
Hi to everybody,
I would like to know if anybody can make any guess on the root cause failure of the following metal screaper seal on a hydraulic cylinder.
Thanks
I would like to know if anybody can make any guess on the root cause failure of the following metal screaper seal on a hydraulic cylinder.
Thanks





RE: Scraper failure
Bent rod.
Ice.
Ted
RE: Scraper failure
Can you tell me what is your idea behind ice as possible cause?
I will exclude pressure, while I still keep bent rod as
possible cause.
Thanks
RE: Scraper failure
Ted
RE: Scraper failure
RE: Scraper failure
Put a pressure gage in the rod end. Make sure it has a damper, and a full scale range at least twice the nominal system pressure.
Mike Halloran
Pembroke Pines, FL, USA
RE: Scraper failure
I will exlude pressure becasue that seal is just a scraper whose function is to keep dirt away from the main seal.
The failure accured after few weeks of the machine installation, and the load condition were below average.
As first level of analysis I will say that the scraper at some point was sticked to the rod surface and was pulled out from it's sit.
Thanks
RE: Scraper failure
Why do you suppose it stuck to the rod?
Or was it not properly installed and the resulting low pressfit pressure could not resist normal rod drag force?
Ted
RE: Scraper failure
RE: Scraper failure
RE: Scraper failure
After reading this post, I can give more ideas (considering the correct installation of the scraper):
Regarding ice. By the way, it's due to know where is working this cylinder. The scraper user, following the sketch (and beware, because, the housing is on the wrong side)this scraper is to be used when several mud, or ice can be expected.
Considering that this scraper is a 2 piece scraper, and both of them is just press fitted, it's very easy that, in case of ice formed close to the rubber part, it takes off on the first stroke.
Regarding pressure. Yes, by the way a scraper is not intended to withstand pressure (althougth lately many manufacturers are using double-scrapers as function of U-lip seal, and a scraper, but I think this is not the case here). As told before, the scraper here is a 2 piece encased wiper (being 1 of them made in rubber, and the other in metal), so, in case of just a minimal pressure received, it wouldn't seal, but neither it will damage the rubber-part of the scraper, unless the pressure is too high, so you need to check the closer seals.
http://www.hidromar.es
RE: Scraper failure
RE: Scraper failure
RE: Scraper failure
Would you like to explain further?
The scraper used is made of two part a metal housing and a rubber part. You can read the code in the sketch I provided (trelleborg brand).
Since I'm not the manufacturer of the cylinder by only the end user, I'm now wondering if they have installed a scraper different from what they have specified (altough to my eyes it looks correct).
Thanks
RE: Scraper failure
RE: Scraper failure
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Scraper failure
Yaa..true, it look like is installed backward.
But I can't get when you say "wiping lip was compressed against the bottom of the step"
Would you like to explain it further?
Thanks
Regads
RE: Scraper failure
Ed Danzer
www.danzcoinc.com
www.dehyds.com