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Tycho
24-02-2006, 11:25 PM
This is something that happened to me a few years back...

Thought I'd share.

Copy of mail sent to friends abroad:

I've just had the scariest closest call I have ever had during my nine years in this job... we were to cut two pipes on a plate freezer (a plate freezer is used to freeze fish into nice 20kg blocks (44 pounds), a freezer has three pipes with various valves, non return and overflow and shut off valves, that regulates the freezing and the defrost. The chief engineer onboard said he had evacuated the freezers and sucked all the ***** back to the liquidtank (liquid tank = a tank that by law is required to hold all the ***** in the plant) and that all the freezers were empty. we had alot of work to do onboard and the pipework on the freezers were kinda inbetween work, my co worker, who were "supervising" this job said we were to change a piece of the liquid and hotgas line (he really meant to say hotgas return valve line), he was welding pipes for a oilcooler, so I went to depressurize the freezer, checked all valves needed, shut of everything in the line we were to work on and sent the last 14 psi overboard through a hose, the chief engineer said he had had shut of all valves, but sometimes they have small internal leaks and 14 psi can be justified to that.
so, the pressure was gone and my co-worker crawls behind the freezer, puts the grinder to a 2 inch pipe and goes at it, I usually make a small hole first to make really really sure the pipe is empty, but he just tore at it, when he is almost through the pipe it blows apart *BOOOOOMWHOOOOOOOOOOOOOOOOOOOOOOOOSH* the grinder disc shatters, I freeze in place like a deer caught in headlights, I want to run, cause I know this is bad bad stuff, but he was behind a freezer, it took him five minutes to get there and I aint going nowhere till I know he is on his way to safety...
He crawls over the freezer (something I thought impossible) grinder spooling down in his hand... He lands on the deck and we both make a run for fresh air, ***** gas (not liquid thank god) rushing out of the 2 inch pipe at 100 psi... We run towards the exit stairs and once close to fresh air, we have a short, 5 sec max, mental check on all the valves and I burst out "Main return valve!!" (the engineer had shut off the return valve on each freezer instead of the main return one, and we were working on pipes connected to the main line), I pull out my trusty 14"... (adjustable spanner that is you dirty dirty minds :)) and run back down into the factory to the main return valve... my 14 inch is to small to get the valve cap off so I run back into the workshop, pick up a pipe wrench and back to the valve, get the cap off, out comes the spanner, I spot my co-worker as he runs up the stairs to fresh air... I'm working that valve spindle as a madman and manages maybe 5 complete turns on it when my brain kicks in again... up until this time I had been in a almost total "panic" to close the valve before it was unbreathable on the factory deck... Thinking I had plenty of time as ***** is heavier than air and I thought it would take some time to fill the whole factory with gas, I start to feel my heart beating at an extreme rate, I see "stars" and then my brain kicks back in, holy crap, hypoxia! I run through the factory towards the stairs up to fresh air, when I get up, my ears are ringing for some strage reason, all sounds are muted, my co-worker tells me that he was about to go back down to get me, I give him a weak smile and tell him I'm ok. The valve is still not closed and we confer and conclude that we should go down in turns of thirty seconds each.
So my co-worker goes back down but reemerges after ten seconds (he's a smoker and probably has less lung capacity), he huffs and puffs and tell me he managed two turns on the valve. I think to my self "f*ck this, at this rate we'll never get the damn valve closed" I tell him to get ready and I take a few deep breaths before I run back down and start working on the valve... man does it take alot of turns to close it... I'm turning and turning on that damn valve trying to close it, then I notice that my toes start tingling, a few seconds later my knees are shaking and my heart is working at an even more unbelievable rate than the first time, my hearing is close to gone again, and my vision is fading doing the scooby doo scene change effect (without the music tho :)) and the air or whatever it is I'm breathing starts tasting kinda sweet...

the valve is closed

I run/stagger to the ladder and pull myself up to the deck, I meet my co worker on his way down the ladder, we both enter the sweet sweet fresh air... might not have been fresh, but it's the best thing I have ever felt, My co-worker said I looked like a robot when I stumbled out the door and he was on his way down to drag my body out of there (his words, not mine :))... Luckily we both escaped without harm, but it's by far the worst and scariest episode I have ever had.

Usually I am very very bent up on double checking the valves before doing any pipe work, and I have never found anything wrong... until this time where we were short on time and had (for once) a competent chief engineer).


From now on, I will trust myself and myself alone when it comes to valves :)



I hope you all read through this and dont do the mistake I did... dont ever trust anyone with your life like this, if you are doing work that might affect yourself if it's not properly prepared, always double check. And last but not least, it's better to lose $50.000 in ***** then to lose your life.
we have an escape kit with 30 minutes of fresh air at our workshop, but we were to stressed out to think of driving the ten minutes to our workshop to get it... guess the boyscouts hat it right when they said "be prepared"

chillin out
24-02-2006, 11:50 PM
That was a close call mate, good to hear a happy ending though.

I heard a similar story once but is was with ammonia and both guys died.

Chillin

US Iceman
25-02-2006, 12:21 AM
One afternoon we were working on an ammonia system used to cool calcium chloride for soil freezing. The screw compressor was shut off and the oil filter housings were depressurized to change the oil filters.

Everything was going fine until my co-worker came into the trailer. Oh, I forgot to mention this system was inside of an enclosed 40 ft. semi-trailer.

There was about 12 inches of clearance between anything in this trailer. The motor starter, control system, receiver, condenser, chiller, and screw compressor were all inside. Not much room to work.

Back to the story...

Someones shirt got caught on a 1/4 turn ball valve. Anyone want to guess which valve it was?

The valve happened to be the one I closed to isolate the oil filter housing. Within seconds I found myself trapped in this trailer with 100 psig ammonia vapor hitting me in the chest. The guy who opened the valve accidentally froze in surprise.

I had to hit him to get him to move and then we both tried to work our way through the 12" clearances until out of the trailer.

Lesson of the story... Always lockout valves during service. And never let anyone stand in your way to safety!

Sometime I'll tell you the story about the 4" hose that burst with -20F calcium chloride in it.:eek:

If I was a cat I would be down to 7 lives. The first one was my mistake not for locking out the valve. The second was pure accident. Wrong place at the wrong time.

Want to guess how hard calcium chloride will make your clothes?

Andy
25-02-2006, 10:27 AM
Hi Tyco/Iceman.
I so far have lived a charmed life, the only near one was whilst changing a single relief valve that had been fitted to a receiver (r22) pumped it out, and recovered all but 4 psig of the gas. I started to screw off the relief, after protests from my co-worker, it will be fine a said, as the relief valve came to the end of it's treads, blew out of my hand and went straight over the top of the evaporative condenser beside me.

Had I been bending over the valve, it would have killed me. The receiver had some liquid in it, the pressure was rising all the time I was un-screwing the valve, it blew the valve in the air like a rocket.:o

Should have pulled the pressure down into a vacumn and bored a vent hole in one on the nozzles on the receiver.

Won't be doing that one again:D

Also remember the burning pain in my nuts after going in to isolate an ammonia leak on a high level gantry, no BA on site, just a mask:(
Half way up the 30' ladder the ammonia started to come thru the mask, options were to go down into the cloud of ammonia below me or to hold my breath and keep going, reached the top of the ladder and ran down the gantry, pulled of the mask, lucky for me there was breathable air up there.:D

Won't be doing that again, no BA set no Chemical suit and no back up.

Probably only saved a few bottles of gas anyway as I had to add 3000kg to make up the loss, 1/4" hot gas pilot line to the suction solinoide had been leaking all weekend.

Kind Regards. Andy:)

chillin out
25-02-2006, 10:27 AM
Want to guess how hard calcium chloride will make your clothes?
Hope you didn`t spray it anywhere else!!!!! LOL

Theres pills you can take for that at your time of life...

Chillin:) :)

phil68
25-02-2006, 01:47 PM
Was the stopping the escape of the ***** really worth risking your life for? OK, if it was going to endanger other poeple's lives then maybe the heroism was called for. But to stop the escape of ***** for purely monetary reasons I would've let it escape & let the engineer who made the mistake take the rap. This may sound harsh but hopefully then he wouldn't make the same mistake again.

US Iceman
25-02-2006, 03:29 PM
Also remember the burning pain in my nuts after going in to isolate an ammonia leak :o

Hi Andy. One form of first aid I found that works very well for this problem is the same ointment that is used for diaper rash on babies.

It is rather humbling, but it is much better than spending days in agony.


Hope you didn`t spray it anywhere else!!!!!

We were absolutely soaked. The spray went about 40 feet sideways. Of course, this happened to be where we were at!


There's pills you can take for that at your time of life...

I suspected someone would have some comments like this. This should also give you some time to think about this yourself.:p

aawood1
25-02-2006, 07:29 PM
Hi Andy/ US Iceman. I was called back to work one night for an Ammonia leak in a 4" Hot gas defrost pipe line to a Gryo freezer. It turned out that the shift engineer on at the time had found the leak as he had been sitting on the pipe line at the time. He spent the next 20 min. washing his nuts in the sump of a old Halls cooling tower. He did get me one day on a RS mag valve change on the coldstore, He said he had pumped it down and shut all the valves, It was at -15" vac. untill some switched the defrost on and the hot gas started to come from the poilot line made it a bit hot around the nuts and eyes. So from that day on I do all my own pump downs and check any thing that any engineer tells me he has done.

US Iceman
25-02-2006, 11:13 PM
...check any thing that any engineer tells me he has done.

Very good advice. Never believe anyone who say they took care of it. If you are working on it, check it yourself.

Had a similar problem on a 600 volt system. Someone says the breaker is turned off. It wasn't. I have not believed anyone since. I think the water behind my ears and beginning experience made this a very important lesson.

Tycho
27-02-2006, 12:00 AM
Phil68: Nope, wasnt worth it :) but, I didnt think it would get that bad that fast, and when it indeed did, adrenaline did all the thinking I guess...


will never do it again to, and as aawood1 said, from now on I always check and double check the valves, even if I was the one who closed them :)



ah, ammonia... dontcha just love it :)

was changing a refrig pump on one of our plants (spray cooler, RSW http://www.pbase.com/kimmo98/image/49607773.jpg )
if you look at the picture, you can barely see the pump, under the cooler to the left.

No pressure, all valves closed.

I was standing with a leg on each side of the pumps suction line and tilted the pump away from me :) needless to say, the small amount of gas still left in the pump and pipes rose straight up to the place where it was most painfull...

tangled up between pipes there was nothing to do but get the pump out, then me, then a short run to wash the equipment in the nearest sink :D

wambat
27-02-2006, 01:14 AM
Speaking of close calls, I was changing out a defective seal on a 5H60 Carrier compresor which was connected to a 100 HP double ended motor with a 5H 40 Carrier on the other end. This unit was close to a cement wall which was about 1/2 meter away. I was alone in the room, in the pent house whan another mechanic walked in to see if I needed any help. I said no, and I was just in the process of turning the coupling and shaft over to tighten the other bolts on this Thomas coupling, I picked up my socket wrenches and was starting to tighten the bolts when.... Yes you guessed it! the motor started and both wrenches flew out of my hands. Would you believe that both mised me:eek:
As I am one who believes in God, I believe the force was with me at that moment. If any of you are familier with a Thomas coupling you know that they can be quity large and they have many disks and bolts to provide flexibility so whan you turn the motor shaft over you usually put your fingers in between the spaces and turn the shaft over that way. What happened was the other mechanic went in the motor control panel room and decided he was going to protect me by turning off the the main circuit breaker ...instead he turned in on. Needless to say he didn't come out of that room until I went to see what the hell he did that for:confused:
He was shaking and had tears in his eyes, actually he was in more shock then I was. I NEVER GOT MAD AT HIM as I knew it was my bad because I didn't lock out or tag the breaker. I was just glad to be alive with both hands and arms intact. :D I believe I learned a lesson that day and always tagged and locked out the equipment. I do have other close but that was the worse.

US Iceman
27-02-2006, 01:30 AM
Hi wambat,

As your story points out this is a very good reason for not wearing neck ties in an engine room. I have seen this too many times.

As anyone who has had a close call can attest to, you do things differently the second time.

US Iceman
27-02-2006, 01:32 AM
...then a short run to wash the equipment in the nearest sink

Do you have to have personnel safety showers in the engine rooms in Norway?

wambat
27-02-2006, 01:43 AM
Hi wambat,

As your story points out this is a very good reason for not wearing neck ties in an engine room. I have seen this too many times.

As anyone who has had a close call can attest to, you do things differently the second time.

I have never known a Refer Mechanic who wore a neck tie but I knew some Steamfitters who did.:D :D :D
As I often worked with steam fitters we were always picking on each other.

Tycho
27-02-2006, 07:02 AM
Do you have to have personnel safety showers in the engine rooms in Norway?


yup, safety showers outside every door leading in to the refrigeration machinery room, if it's ammonia... most ships throw in a sink with warm and cold water taps at one of the entrypoints

nh3wizard
01-03-2006, 07:51 PM
Glad to hear everyone was safe, I never trust anyone, always double check it myself.

Frosty
01-03-2006, 10:37 PM
Gent's some people say UK health and safety laws are strangling business - I say, I would rather work to procedures, method statements etc than have to face the awefullness of telling one of my workers wifes/children that there father has been killed in a tragic accident! We've all been there, I took a risk many years ago, I decided to shim down a cold room, high-level ceiling onto a lower level, I used the suction line and a purling to navigate my way down. The purling gave way and I landed back first across a horizontal suction line!! All around me were 12mm cooler support rods - I could have been well and truly 'speared' Think about it...risk assessments and method statements are there for a reason!! PS, I still suffered cracked vertabrae and broken ribs...but I live to tell the story. Be careful, it's a dangerous industry.

Andy
02-03-2006, 08:21 AM
ah, ammonia... dontcha just love it :)

was changing a refrig pump on one of our plants (spray cooler, RSW http://www.pbase.com/kimmo98/image/49607773.jpg )
if you look at the picture, you can barely see the pump, under the cooler to the left.

:D

Tyco,
nice piece of kit you have there. What type of compressor, it looks familar, but I can't put a name on it.


Kind Regards. Andy:)

Andy
02-03-2006, 08:29 AM
Hi :)

It seems that the industrial refrigeration industry has more potential to kill and injure that other branches of the family.

All those who have posted are competent experienced engineers and yet all have a story of danger to tell.

I suppose we could all change to A/C or Commercial refrigeration, health and safety might be a bit better, but it would be a bit of a no brainer:D

Kind Regards. Andy:)

frank
02-03-2006, 02:05 PM
The purling gave way and I landed back first across a horizontal suction line!!

Hi Frosty mate :)

Looks like you've always had a weight problem then eh? :D :D

Tycho
02-03-2006, 03:59 PM
Tyco,
nice piece of kit you have there. What type of compressor, it looks familar, but I can't put a name on it.


Kind Regards. Andy:)


It's a Howden XRW 204 :)

and just noticed I said the pump was on the left, my bad, the pump is to the right :)

nice units indeed :) this one is a 950Kw unit charged with ammonia...

Wanna make a quess on the size of the ammonia charge?

Andy
02-03-2006, 06:40 PM
Tyco
I have worked on HOWDEN wrv and the xrv. Would this be a replacement for an XRV. The xrv was a great effecient compressor with roller bearings which has a habit of wearing out quickly and wrecking the compressor.

Refrigerant charge at a guess 300kg, charges are getting smaller every year.;)

If it is any old design you could have 800kg in there:eek:

Kind Regards Andy:)

Tycho
02-03-2006, 09:10 PM
Not sure what you mean by "replacement for an XRW" but I'll go ahead and make a guess :)
This is the original XRW 204 we installed approx 2 years ago, still havent reached it's hours so it hasnt been serviced (other than a shaft seal change)

we've been using the XRW range for 5+ years with no problems other than the odd shaftseal leak (mostly the last two years as howden probably changed manufacturer, tho they denied it :)).

before that we have used the WRV range almost exclusively, only the odd bitzer on some smaller plants.

around new years I recomissioned a trawler with two WRV 163's with close to 200.000 hours under their belt:eek:


and last, on the ammonia charge... :) didnt think you would be that close.. the charge is around 150-250 kg, depending on the size of the chiller.
the ammonia is sprayed over the tubes and the charge only fills up the "udder" (least thats what we call it, the part that sticks out below the chiller)


Cheer

Tycho

Mark C
03-03-2006, 04:23 PM
ah, ammonia... dontcha just love it :)


Yes, At least I know its in the atmosphere!

Andy
03-03-2006, 08:09 PM
Not sure what you mean by "replacement for an XRW"

and last, on the ammonia charge... :) didnt think you would be that close.. the charge is around 150-250 kg, depending on the size of the chiller.
the ammonia is sprayed over the tubes and the charge only fills up the "udder" (least thats what we call it, the part that sticks out below the chiller)


Cheer

Tycho

Howden introduced a roller bearing compressor, XRV 204, Star refrigeration fitted a few, they all blew up, no oil pumps used and very little in the way of oil in the system. Star blamed Howden, Howden blamed Star.
I would say the truth lay between, Stars oil system was not good enough, too much carryover in the separator and too little oil in reserve, until the oil came back. Also Howden farmed out the casing casting to the Kiloskier Electric Company in India, maybe not the best thing to do with a prototype compressor, apparently they switched the casing manufacture to the UK and a lot of the problems stopped. Star never use XRV compressors;)

If your compressor has roller bearings in it and a spring to return the slide, it is a re-badged XRV;)

Better to inspect the slide and the bearing tolerances once a year, if you kit the slide and change the bearings when they are just about to go out of tolerance, the compressor will be fine for as long as the WRV range.

WRV 163 compressors are very popular over here too:D
good compressor, very easy to work on:)

On the shaft seals, it is probably the orings failing, the standard orings are not suitable for most refrigeration oils (especially PAO oil), Howden keep quiet about that unless you push them on it:confused:
You can ask to have other types of orings, special order, but not very expensive.

Spray chillers are the dogs nuts:D Whitt make the most popular in the UK, very cold water off temperatures, without the risk of freezing.

Kind Regards. Andy:)

Tycho
03-03-2006, 09:55 PM
Howden introduced a roller bearing compressor, XRV 204, Star refrigeration fitted a few, they all blew up, no oil pumps used and very little in the way of oil in the system. Star blamed Howden, Howden blamed Star.
I would say the truth lay between, Stars oil system was not good enough, too much carryover in the separator and too little oil in reserve, until the oil came back. Also Howden farmed out the casing casting to the Kiloskier Electric Company in India, maybe not the best thing to do with a prototype compressor, apparently they switched the casing manufacture to the UK and a lot of the problems stopped. Star never use XRV compressors

We dont use oil pumps on our XRW units, only on the WRV units, tho the oilseperator holds 80 - 180 liter of oil depending on compressor size. We've never had a XRW breakdown to date *knock on wood* only a few 127's serviced on the hours.


If your compressor has roller bearings in it and a spring to return the slide, it is a re-badged XRV

Doesnt all XRW's? the XRW cap slide is open to the rotors on one side, using the spring to decrease cap.
the WRV on the other hand has a sealed cap chamber, using oilpressure both to increase and decrease cap.


Better to inspect the slide and the bearing tolerances once a year, if you kit the slide and change the bearings when they are just about to go out of tolerance, the compressor will be fine for as long as the WRV range.

we've been running them on hours, but then again, we also use inverters :) at start up we take them to 1800 rpm, then we increase the cap slide to 100% then we regulate the speed from there :)

WRV 163 compressors are very popular over here too:D
good compressor, very easy to work on:)

and to think the WRV range is the Howden "Rolls Royce" :D with all those bearings you would think the XRW was the top of the line , not the simple WRV :)


On the shaft seals, it is probably the orings failing, the standard orings are not suitable for most refrigeration oils (especially PAO oil), Howden keep quiet about that unless you push them on it:confused:
You can ask to have other types of orings, special order, but not very expensive.


Hmmm... ya dont say... *rubs chin thoughtfully*
we've always thought it was the carbon rings that gave way... thanks for the heads up :)


Spray chillers are the dogs nuts:D Whitt make the most popular in the UK, very cold water off temperatures, without the risk of freezing.

indeed, we take the seawater down to -1.7C

Andy
04-03-2006, 09:28 AM
We dont use oil pumps on our XRW units, only on the WRV units, tho the oilseperator holds 80 - 180 liter of oil depending on compressor size. We've never had a XRW breakdown to date *knock on wood* only a few 127's serviced on the hours.

Stars units only held 40 litres of oil and that was on a 204

we've been running them on hours, but then again, we also use inverters :) at start up we take them to 1800 rpm, then we increase the cap slide to 100% then we regulate the speed from there :)

We are trying a WRV163 on inverter drive, aparently minimum speed in around 1500rpm


indeed, we take the seawater down to -1.7C




At least we now know where the XRV went, it was re-developed into the XRW, should be very effecient, the XRV was.

Kind Regards. Andy:)

aawood1
04-03-2006, 07:42 PM
Hi Andy,
We now have 3 WRV 255 on the site I look after they have all been fitted onto Grasso MS 1034 base units. We still use the Grasso oil seprator and oil pump with about 255 lts of oil. The only fault that was left for me was when one of them stoped it sucked the oil out of the seprator below the oil level switch cut out. What I came up with was to fit a 22mm pipe back into the 8" main suction line with a EVRA 15 valve that opened when the compressor stoped. This has worked well now for about 2 years. After all that I still like the old Grasso MS compressor units just fun trying to get some of the parts from Grenco (O sorry I should say GEA ). I had some fun with the shaft seal's on the howdens found out it was the "O" rings and they said it was a supply fault to them at the time.
Regards Arthur

Andy
05-03-2006, 10:03 AM
Hi Arthur:)
WRV 255 would be a decent size, I have overhauled a WRV321, but it was only running at 1500RPM on a 3300 volt motor, so it had no more capacity than a WRV255.

The Grassos you mentioned, are they the mono screws:confused: I have to say I have never even seen one never mind worked on one.

We would buy our Grasso spares off Grasso Products (Grasso UK), We are an agent for Grasso, but I think anyone can buy off Grasso UK:)

On the oil scavenge pipe, the Halls screws have this fitted, with an optical sensor to check if they are drained out. How does the oil get in the suction line:confused: or is the solinoide just equalizing pressure to allow the oil to flow from the separator section to the oil tank.

Nice to see units this size being retrofitted, some real engineering, instead of a new unit being bought in from some part of the world that pays $5 a day:D


Kind Regards. Andy:)

aawood1
05-03-2006, 07:46 PM
Hi Andy,
Yes they are the old Grasso Mono screws. When I started on this site we had 6 MS 1034 units working as boosters ( low side) and 2 MS 1030 units working on high side with 2 RC 11 9 cylinder compressors converted to work on the high side. Only two of the MS 1034 units on this plant have been changed over the over one is on a stand alone plant that works a Frigo Gryo 92 freezer. We still have two new Grasso MS 1030 units in the stores at this time, the last one I fitted was 9 years ago. The 22mm pipe was taken from the compressor by-pass line so it lowerd the pressure in the oil separtator more that the compressor unit and stoped the oil filling the compressor. My avator is the input shaft and gland of a MS 1030 that I serviced this year when the motor whent Bang at a 187 KVA (a good Bang) all 780 KG in weight. The Grasso MS looks the same as the halls unit but the loading gear is on top of the compressor. I Will see if I can work out how to add some photos of then so you can see what they look like.
Regards Arthur.

Andy
06-03-2006, 09:01 PM
Hi Arthur:)

Photos would be great:)

Unusual plant, I can only think of one site with these fitted, having said that I have never seen them. Must be the solinoide passing the oil into the compressor, or the discharge into the separator working as a dip pipe.:)

Kind Regards. Andy:)

aawood1
07-03-2006, 07:25 PM
Hi Andy, What was happening was the oil was sucked from the separtator into the compressor head via the oil pump. The Grasso has a 40mm by-pass line from the separtator to the under side of the non-return valve, With a PML that opens when the compressor stops to unload the discharge pressure into the suction of the head.
If you let me have a post address I can send a CD with some photos of the ammonia plant/compressors and a small one that I look after with two Frigo Mini gyros and two Grasso K110 units one 9 cylinder and one 6 cylinder.
How would you like a Grasso instruction manual for the MSU 10E (Works address will do)
There is not alot one can do the the MS 1030/1034 units, Just oil and filters, Gland service ( I still take them apart and lap then on the face plate and fit new "O" rings.) Have had one apart and fitted a new loading gear ring and the drive coupling for it under the motor.
regards Arthur.

Andy
07-03-2006, 09:05 PM
Hi Arthur:)

Yes please send me the photos, (we will get then on the web some way or other) the manual I might have, I have just found the design Data and the sales glossy on the MS 10. The capacity control is via a rotary ring, with a slot cut in it and the main rotor is made of an aluminium alloy, now this is not just a Halls Screw copy, like all the others out there.

Andy Dunwoody
Cross Refrigeration
Hamiltonsbawn Rd Ind Est
Armagh.
BT60 1HW

Kind Regards. Andy:)

Tycho
07-03-2006, 09:07 PM
Hi Andy, What was happening was the oil was sucked from the separtator into the compressor head via the oil pump. The Grasso has a 40mm by-pass line from the separtator to the under side of the non-return valve, With a PML that opens when the compressor stops to unload the discharge pressure into the suction of the head.



The pipe is connectet to the separator above the oil level, yes? so that when the compressor stops, this ensures both that the compressor doesnt counter rotate and equalizes the pressure, without the oil being pushed back up into the compressor.

am I correct?

Frosty
07-03-2006, 10:17 PM
Ya cheeky ******* Frankie...lol I'll let u in on somethin, I normally do those kind of things when I've got my ACME jet pack on!!!!!! I just forgot it that day - hee hee

aawood1
08-03-2006, 04:54 PM
Hi Andy, The CD is in the post now. Have seen the Halls Mono screw all striped out back in 1989 in Dartford at the factory when on a Halls training course. If I can remember the Halls fitted a special plastic to the star tooth the Grasso did not have this. About 12 years a go we tryed to get the rear bearing from SKF but they said it was a special made for Grasso. So we had to change the unit over as it had 0.65 mm of play side to side and could not get the radial/ axial alignment of the drive to less than 0.15 mm. and start to cut the rotor up.
Regards Arthur

Andy
08-03-2006, 10:28 PM
Cheers Arthur:)

What were the star wheels made off:confused:

Kind Regards Andy:)

US Iceman
09-03-2006, 02:46 PM
We are getting off topic a little bit here, but I will add some information about the star wheels. On this side of the pond we call them gate rotors.

The gate rotors are made of a proprietary plastic developed by Phillips and Vilter. It looks like a carbon fiber composite material. The plastic comes in large sheets which are cut out in the general shape and then the edges are machined on a special milling machine.

Andy
16-03-2006, 08:57 PM
We are getting off topic a little bit here, but I will add some information about the star wheels. On this side of the pond we call them gate rotors.

The gate rotors are made of a proprietary plastic developed by Phillips and Vilter. It looks like a carbon fiber composite material. The plastic comes in large sheets which are cut out in the general shape and then the edges are machined on a special milling machine.

Hallplas is what Halls call this, black with fibre running thru it. Gate rotors are what Dakin call it in their mono screws.

Kind Regards. Andy:)

aawood1
16-03-2006, 09:28 PM
Hi Andy, Did you get the CD and manual in the post ok. Grasso did offer a 3 year return on each unit for service but they stoped it befor we could use it as the ones we have where built in 1983 to 1984. They did not like any liquid in the return gas so we fitted a slop pot at the low end of the suction header with 3 heaters. I think we will have to fit a new Howden some time soon as one of the MS 1034 units is hot on a star wheel bearing on one side. That's if we are still working on this site, Should be looking for a new job !!!.
All the best,
Arthur

Andy
16-03-2006, 10:20 PM
Arthur,
I did get it, some nice compressors, usual but nice, also the manual:)

What part of the world are you in, you shouldn,t have much problem getting a job at Industrial Fridge, I can point you to a few people if you want:)

Kind Regards. Andy:)

Andy
16-03-2006, 10:24 PM
Arthur,
I looked at you profile, there would be plenty of job openings in your part of the world:)

Kind Regards. Andy:)

aawood1
17-03-2006, 07:33 PM
Hi Andy,
Yes please if you can point me to some people in Industrial Fridge.
Thanks Arthur.