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Gage

Help from someone preferably experienced in Vacuum Furnaces, more specifically Consarc.

Now to the point, right now at work we have an issue with a Furnace, I've managed to work out (after hours of wasted time leak detecting) that what is happening is at the pumps there is an Electronic Vacuum Gauge (more importantly a Vacuum Gauge meant for another Furnace however one of the Engineers swapped it over). This Gauge is not reading the correct pressure and is therefore sending the 'wrong' information to the PLC which automates the Mechanical Blower, currently the lowest the Gauge reads the Furnace reaching is 4.4 x 10^+2mbar, the PLC needs to read 1.2 x 10^-1mbar to kick in the Mechanical blower. Now I know for a fact that the Furnace is well below that 4.4 x 10^+2mbar because the liquid-filled pressure gauge which is definitely working correctly is reading it's minimum (-1) which means it's below 9.9 x 10^-1.

The problem I have is that the engineer in my maintenance department...the expert on all things to do with our factory, and the man who switched these gauges, is on his holidays and is sick of being 'abused' and called in from his holidays so he's in a huff really and won't accept our calls and so on. I'm only his apprentice however it would seem I understand a lot more about the problem than the rest of the maintenance team currently here, I've tried explaining but they simply don't understand...or don't trust my verdict because of my experience and won't do anything about it, so the boss is going crazy because of lost production time and what not. My question to you guys is: There's a 'trip' on the Gauge where you can alter it manually with a terminal, should I alter it to read the correct pressure/at least read below 1.2 x 10^-1mbar. And also just to confirm with myself, does my theory sound viable? :hippy:
 
I would consult a professional calibration service company in this case. It might cost you a hundred quid to het the gauge calibrated but it is done correctly and documented and verified. You need special equipment anyway to undertake calibration. Don't be tempted to "tweak" the plc software or so. If something bad happens you are liable for it.
 
The Engineer who is on his holidays is qualified to perform an extremely broad range of calibrations on thermocouples and instrumentation. There is no need to contact a calibration service and spend more money that way. Lost production time is slowed through using a different furnace, luckily the work at the minute is not atomosphere specific, literally all we need is for the PLC to read the right pressure to kick in the blower. He's back on Tuesday I was just seeing if I could do anything to get the furnace back up and running. The tweak I would be making is not to the PLC it is to the instrument which the PLC reads, the Gauge, the Gauge itself is not particularly sensitive as it is relatively cheap compared to more sensitive gauges.
 
He may be qualified but he's not there. Get the original sent off to the manufacturers or someone like Dowding & Mills.
 
The boss won't allow it, it's not the way he sees things. He sees spent money a lot clearer than lost money.
 
Safe to say he's not the most loved man in the factory. Runs every machine in to the ground with his ways. Keeps us busy though I suppose and also keeps my Apprenticeship fresh haha. Always learning something.
 
"Runs every machine in to the ground... " + "... I suppose and also keeps my Apprenticeship... "

Oh dear... that's your gaffer you're publicly slating... who's been good enough to give you a start in life.

As Tony said, your man aint there, and from what you've said - he's on holiday - tough. Get the right instrumentation on or fixed.

Good luck!
 
Slating and thanking :sick:. But thanks for all the advice boys. Can't get the right gauge on since it he tweaked that one for the furnace he switched it to. Suppose it's a waiting game now.

Cheers
 
Your gauge needs its calibration checking using some sort of pressure calibration unit like a Druck, its needs the zero/span setting correctly. If there isnt anyone in house who can do this your best bet is to get it sent off to be calibrated as others have suggested.
 
The Engineer who is on his holidays is qualified to perform an extremely broad range of calibrations on thermocouples and instrumentation. .

Sorry, i wonder that he has changed an item that is obviously different in set up and he fails to test it afterwards.
Anyway, i read it that it is a pressure switch that you are talking about if you can adjust it with a terminal driver? does it provide a simple on/off to the PLC or is it an analogue signal, i suspect the former, is it wired accross the N/O or N/C terminals & what should it be? Is the old gauge still about to check what the setting was, or are the scales different, too many questions remain.
Then think of what the consequences are if your wrong to adjust, the guy who changed it didnt.
Its just as well to buy the right item for the job instead of mucking about with odd parts from here and there, its ok your gaffer running things on a shoe string but its at the cost of production.
 
Problem is now solved, turns out that the pump had actually quite simply smashed itself to bits inside after having its old dirty oil switched for some beautiful clean stuff it just couldnt handle running smoothly. Main fella knew it straight away, I have a lot to learn! And Malc he did test it and calibrate it for the machine and it was and is still working correctly. I suppose I have been doing some slightly radical thinking!
 
at least its sorted m8, nothing wrong with being inquisitive and challenging things, thats what makes us better. thanks for the feedback
 
Problem is now solved, turns out that the pump had actually quite simply smashed itself to bits inside after having its old dirty oil switched for some beautiful clean stuff it just couldnt handle running smoothly. Main fella knew it straight away, I have a lot to learn! And Malc he did test it and calibrate it for the machine and it was and is still working correctly. I suppose I have been doing some slightly radical thinking!

You do have a lot to learn like we all do but it's great to see your enthusiasm kicking in.

Ill give you a little advice though, no doubt your boss does want everything running etc and there's always a way around things to get them moving in an emergency situation but be aware that if the poo hits the fan your boss will NOT back you in anyway, I'll guarantee it as I,along with no doubt many others on here have had to do this and experienced it when things go wrong and I don't mean injured but machinery breaking etc, your then the "w4nk3r" that frigged the plc rather than the "hero" that saved production.

And remember in industry what's a favour today is practice tommorow.



Second piece of advice?


Its ALWAYS mechanical!!!!!!
 
You said the gauge fitted to the furnace was showing -1 maybe this gauges calibration should be checked as it did not agree with the PLC/transducer.

Depending on the increments on this gauge of course, if divided into 200mb sections that wouldn't be accurate enough to tell.
 

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Need help concerning Vacuum Gauge Calibration
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