Howden compressor failure

[Surveyor Paul]

We have had a failure of a new Howden oil injected compressor after only 15 hours of running. The scrolls are bent and have touched the casing towards the outside. I have been advsied that this type of failure is due to liquid carry over or excessive oil. Has anyone seen this type of failure before and what could cause it?

[Josip]

Hi, Surveyor Paul :)


We have had a failure of a new Howden oil injected compressor after only 15 hours of running. The scrolls are bent and have touched the casing towards the outside. I have been advsied that this type of failure is due to liquid carry over or excessive oil. Has anyone seen this type of failure before and what could cause it?

welcome to RE forums ... we have one forum New to RE http://www.refrigeration-engineer.com/forums/forumdisplay.php?f=72 (http://www.refrigeration-engineer.com/forums/forumdisplay.php?f=72)where you can tell us more about yourself, of course if you want to....


... sorry about your loss, but back to your question...


yes, back in 1992 in Libya I saw one broken Stal vertical screw after few hours, but due to incompetent operator (override oil pressure safety switch instead to replace clogged oil filters) :rolleyes: we had to replace complete compressor...

this type of failure can be due to liquid carry over or excessive oil, but I do not believe that can happen within one moment at least I have never ever heard something like that:confused:

.... i.e. compressor was running for many hours and there were some other indicators not recognized by anyone or compressor was working without surveying what mean that safety instruments were setup wrong or override ...

... otherwise you can see some changes of pressure, temperature, but the most powerful indicator is a strange (scary) noise coming from compressor and it must be stopped immediately and checked ...


.... was that a new compressor?

.... start up done by Howden representative or by your commissioning/start up engineer or by someone else??

I believe some other RE members will come with some other opinion, but I believe with some other questions too...

Best regards, Josip :)

[Surveyor Paul]

Thanks, It was a new compressor replacing an identical unit in a factory system. The compressor was installed and commisioned by a local service technician and then operated by factroy staff. The compressor had been running in parallel with an identical unit supplying 3 tunnel freezers and 2 plate freezers. The plate freezers were shut down, the other compressor shut down and the new compressor was left running. Two of the blast freezers came down to temperature with the final one some way to go. Within an hour of shutting down the other compressor, the new compresor failed.

[RANGER1]

Howden are probably most reliable screws compressors ever built .

If high level cut outs and all safeties work then its a mystery .

Usually it would be a long rotor machine that rotors flex and damage rotors and housing , due to liquid slug while machine was running .

I don't know for sure but all machines would be tested before despatch from Howden factory .

What will you do next ?

[Magoo]

Sounds like you have fixed the result and not addressed the actual problem. Howdens would have to be the most bullet proof screws around. So if a rotor is bent then it has receieved a large chunk of liquid, and of course you cannot compress liquids, hence bent rotor.

[la461]

Is the oil injection valve through the super feed port or the factory port? What size is you compressor? We lost a MK4/WRVT/255 rebuild in 45 minutes due to the oil manifold valve on a Vilter package delayed opening and no pre-lube oil got to the thrust bearings causing catastrophic bearing failure. It also damaged the inlet mains allowing the rotors to move radially rubbing the rotor housing. Pre-lube can cause the compressor to have too much oil in the rotors at start-up cause thrust bearing to be stressed cracking the bearing cage and allowing the balls to gang up. If it was liquid the compressor should have been a ball of ice. If the compressor was warm it is an oil issue.

[PaulZ]

Hi Paul
As Ranger 1 and Magoo have said Howden screws are pretty bullet proof. I have had them pull liquid over in small amounts with no adverse effects as long as it is not for long periods. I was once told they could handle about 30% liquid but have never seen it.
It seem odd that you had one blast running and within an hour of the other compressor shutting down this one failed.
Did you notice if in that hour any of the other rooms come on?
If it has bent the rotors I would be pretty sure it's a massive liquid slug.
do some investigating and let us know what you find.
PaulZ

[dvtruc]

Hi all,

If it happened at starting, it may be oil problem, but normally it locked rotors and caused motor overloaded. If failure was at compressor running, liquid overflow was high possibility - means lack of low superheat protection in compressor controls.

Truc