Results 51 to 100 of 169
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23-07-2013, 12:52 PM #51
Re: saturated conditions in a receiver tank PROVE ME WRONG
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23-07-2013, 01:52 PM #52
Re: saturated conditions in a receiver tank PROVE ME WRONG
Question mad man when replacing an old r12 system with the409a and you have a non adjustsble txv why do u only charge the system tby looking at sightglass and only fill it t o say 60-70% full what is the reason for this and if u don't and fill it completly what will happen and why
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23-07-2013, 07:49 PM #53
Re: saturated conditions in a receiver tank PROVE ME WRONG
The algorithms were pioneered by R.Stewart, S. Penoncello, and R. Jacobson about 35 years ago. I briefly worked for them as an undergrad assistant, processing some of the data. The algorithms are available in peer reviewed publications. As for who designed the computer, I'm not sure why that would be significant.
YOUR QUOTE…..
The study of thermodynamics involves years of learning basic rules, followed by more years of learning that the rules don't apply to the real world. Most of us never reach the second stage.
PICK UP YOUR TOOLS investigate theory and cross refrence that to the real world…
THE ONLY DIFFERENCE IS I WORK 80 HOURS A WEEK UNDER THE PUMP…….
Back to lurking in the shadows...........Last edited by frank; 23-07-2013 at 09:31 PM.
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23-07-2013, 08:01 PM #54
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23-07-2013, 08:41 PM #55
Re: saturated conditions in a receiver tank PROVE ME WRONG
Engineering manager for a chemical batch plant in the southern USA. I am trying to bring our refrigeration work in-house so we don't have to rely on contractors, the nearest of which is an hour away. We have a technician with HVAC experience but his methods are a little out of date. Much has changed so we are learning it together.
Last edited by frank; 23-07-2013 at 09:32 PM.
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23-07-2013, 09:03 PM #56
Re: saturated conditions in a receiver tank PROVE ME WRONG
not to bad a description.
The question on the sheet of metal was a trick question, as you know.
The temp on each side of the metal will be different and each side will not be the same as either air temp.
The same with your measuring methods, therefore you can not support your arguments your data is flawed.
There is a saying "shyte in -shyte out" because your raw data is shyte, then so is your assumptions.
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23-07-2013, 09:09 PM #57
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23-07-2013, 10:54 PM #58
Re: saturated conditions in a receiver tank PROVE ME WRONG
so you are an engineer
you know exactly how I txv works from a textbook but when applied in a real world sit uation you can't even realize that a permanent set valve will usually operate at 4-7k and 409a has a large temp glide from memory about 6-7 k
and if the piece of metal you're talking about was thin enough and sat in that condition for a long time it would eventually becomes 30 degrees and then the air above it Would start to rise in temperature too how does energy flow always to a lower energy source remember high thermal conductivity value of metal as well
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24-07-2013, 12:14 AM #59
Re: saturated conditions in a receiver tank PROVE ME WRONG
and to add to this the air is static the metal would become 30 degress (conduction heat transfer) the cold air would not be cooling it down, cold does go to hot,it would be simply sitting above a metal which is heating up very slowly.
keep adding a bit of water on top of the 20 degress side of the sheet and yeah id agree as the liquid would evaporate removing heat in the process so the energy would be consumed by the phase change
and my methods might be flawed in that instance but dont u worry im going to insulate the receiver next time insulate the whole liquid line install schroudour cores above and below the sglass remove drier cores and strainer and somehow come up with an idea on how to get a sensor into the system i found wireless sensors which were 5mm x5mm 1.5mm but the cost $4000 a pop so ill find another way...
oh yeah my digital gauges are awesome much quicker and more accurate then old compound gauges and if ur face plate is out a mm or two you are getting wrong readings anyways i zer my gauges out every time i use them.,...
want to play a game? question for question see who wins the old bull or the young buck
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24-07-2013, 12:17 AM #60
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24-07-2013, 01:05 AM #61
Re: saturated conditions in a receiver tank PROVE ME WRONG
yeah tell the customer to buy a new evap coil oversize it 30% to lower humidity levels, show him how much stock can go in his room....
if he says no
clean evap coil and fan blades, install door/fan switch with big red light so he nos the doors been left open.
clean condensor, check stariner on txv for blockages and correct size if orifice is removable, turn fans off and check txv is able to shut down as it senses liquid at bulb (with no load) clean the bulb location insualte bulb,change drier, perform efficiency test
perform heat load on rooom price him up and new systemLast edited by frank; 24-07-2013 at 06:19 AM.
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24-07-2013, 09:31 AM #62
Re: saturated conditions in a receiver tank PROVE ME WRONG
Oh you are so clever, glide what is that? mmmmmmmmmm. I am sure somebody has already used that term in this thread.
How can the piece of metal become the same temp as one side but not the other, surely as the metal absorbs energy from one side it must also displace energy on the other. So you not quite as smart as you think you are.
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24-07-2013, 09:34 AM #63
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24-07-2013, 09:42 AM #64
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24-07-2013, 10:01 AM #65
Re: saturated conditions in a receiver tank PROVE ME WRONG
True lower ktd sst closer to air on with oversized coil
Had just worked 15 hours
And yeah once the piece of metal displaces heat it is heating up and once it contains the same among of Energy as the air below it ,it starts to heat air above the metal ie it will be 30 the air above would not get to 30 degrees but it would go higher then 20 after a period of time
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24-07-2013, 11:15 AM #66
Re: saturated conditions in a receiver tank PROVE ME WRONG
As there will be minor temp diff as the pipe has a moving fluid inside it its not static like the air you talk of and what ill do smart man is install a sglass o n a stub for a freezer which has a subcooler fitted already so the lines are normally insulated and it is subcooled 20 k and just measure the temp of the outside pipe
Question Mr engineer why did the supermarket have the freezer liquid line ran through a subcooler when there is very low vertical lift in pipe and the pipe run is fairly short ie not 100 meters of pipe run
Let's see if you can apply book smarts to this ill give I a hint.....
Cash
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24-07-2013, 11:47 AM #67
Re: saturated conditions in a receiver tank PROVE ME WRONG
ha ha ha,
If you only knew??? Was not so rude, you could learn something????
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24-07-2013, 11:54 AM #68
Re: saturated conditions in a receiver tank PROVE ME WRONG
you are not the only one who has done 15hrs, apart from setting up all the mechanical, the electro mechainal, electro controls, I also have to write the software program and program the operator interface.
I also use digital gauges, and various temp sensors. But understand that a refrig system is very rarely in a truely steady state, so measurements need to be averaged, not single snap shot in time, and understand where flaws lie with test procedures.
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24-07-2013, 12:25 PM #69
Re: saturated conditions in a receiver tank PROVE ME WRONG
So the answer is Mr setup man
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24-07-2013, 12:25 PM #70
Re: saturated conditions in a receiver tank PROVE ME WRONG
Wrong! you first fix the biggest issue! them not closing the doors! till the box is able to run at design temp all readings are meaningles! and rarely ever will the txv be of issue if the plant was commisioned with due diligence!
Once the box is aproprietly sealed only then do we spend time looking further into the plant, how ever I have told them a good cleaning of the evap would be wise. and a better laged suction line would sofen the blow on their wallet.Now in Redvers Sask.
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24-07-2013, 12:39 PM #71
Re: saturated conditions in a receiver tank PROVE ME WRONG
Why would I waste my time and the customers time and money with all this useles non sense? Non of it is called for!
Better thing to ask your self, with you knowing no details why do pray tell would you even sujest it! Assumption is the mother of all **** ups! untill they get the door fixed and the room sealed again any thing we do on the plant will only hurt in the mean time, other then cleaning the evap and walking away.Now in Redvers Sask.
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24-07-2013, 02:02 PM #72
Re: saturated conditions in a receiver tank PROVE ME WRONG
Besides adding fan switch and alarm light and perhaps a buzzer or fan curtin you can't control them leaving the door open can y ou its always been left open the y aint stopping any time soon and if you did everything I said to do the unit wouldn't be in that state to begin with .no plant room is commisioned perfectly people are lazy just like the way you sound customers are idiotsthey will leave it open the next day when someelse starts there shift and unless you personally no every person who has ever welded a pipe on that unit AMD you are sure they run nitro through it then there is always s h i t in the strainer doors get left open haha mate that coil would have been cleaned drains unblocked txv set correctly after I let the unit get back to temp that is, you are just giving excuses as to why you didn't want to get dirty its a cop out and if the unit is for a leg room what sst is the system running at cause over here in Australia our keg rooms run at 7-10 deg C air temp
Get suppose u could incorporate a pelter some where into the job though LOL
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24-07-2013, 02:46 PM #73
Re: saturated conditions in a receiver tank PROVE ME WRONG
I bet u didn't clean it though
Can u answer my last question to mad man
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24-07-2013, 08:48 PM #74
Re: saturated conditions in a receiver tank PROVE ME WRONG
There are many reasons,
on a supermarket the liquid sub cooling cooling is normally done by the medium temp rack or even an economizer, which in simple terms have a lower compression ratio to that of the freezer.
Plus sub cooling reduces the required mass flow, to the evap to meet a specific duty, which can also reduce the the size of the piping between the the cabinets and the rack.
By the way, you can call me mad fridgie, or Mr mad, but until you show some respect to the you can not call me "mad",
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24-07-2013, 09:20 PM #75
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24-07-2013, 09:50 PM #76
Re: saturated conditions in a receiver tank PROVE ME WRONG
close but no cigar mate....
reduce the pipe size did you even consider my clue.....
CASH.....
supermarkets dont care about mass flow rates all they care about is saving cash....
so im sure in saying that you can figure out what they save by reducing the LIQUID line size...
haha you said pipe... you make me laugh after a hard night at work
so how after years of you setting up all the mechanical, the electro mechainal, electro controls, also writing the software program and programing the operator interface could you not realise that....
and im only 27 and by they way ill tell u a funny story about how i came to no why we charge the sglass to 70% for r12 to 409a retrofit....
as a third year apprentice my boss offered me a pay rise if icould tell him why we charge it to 70% at the time i had never used a PC so googling it didnt come to mind...
so after asking all the tradesman at the company maybe 10 blokes all of which said we cant tell you,((turns out they didnt know anyways, only 2 blokes did) i started ring engineers at wholesalers i rang kirby and spoke to a very smart man who seemed to know everything about the different types of refrigerants how they boil there makeup and i thought to myself (as a 18year old) alright Im getting a payrise.....
so he told me about spefic bheat capacity of 409a and a load of other non sense but it wasnt untill my question of...
so do you use the sglass to charge the system????
and he said "sglass" with a puzzled sound in his voice and i said yeah sglass do you fill it, and his response was....
NO I USE A GAUGE MANIFOLD SET......
and i said no do you look at the sglass and fill it when charging a 409a system,
his response was priceless
whats a sight glass he said.........
i laughed and said ill have to call you back mate then told all the tradesmans what he said..
from that point onwards i realized the difference between a fridge mechanic and a refrigeration/HVAC engineer (also had a good laugh) personally im trying to become both and being a young pup as you so elegantly put it ive got plently of time to do it........Last edited by frank; 24-07-2013 at 10:38 PM.
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24-07-2013, 10:04 PM #77
Re: saturated conditions in a receiver tank PROVE ME WRONG
OH YEAH explain this Mr Mad...
why do we even bother factoring in "heat of transmission load" when performing a full system heat load for a new install, it must be pointless, better yet why use polystrofam its too expensive,we could just use a pieces of sheet metal as the heat would never penertrate the sheet metal all the way through we could save alot of money hey,
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24-07-2013, 10:14 PM #78
Re: saturated conditions in a receiver tank PROVE ME WRONG
one more thing this is for you and big pony
no one has resopded to the little jpg of info i posted which clearly decribes what the state of the refrigerant is in a receiver have they....
nor have any of you replyed to my statement of how stupid u all sound for saying a PT CHART is pointless, hey anyone.....
nor has anyone replyed to me stating the temp on a probe will match the saturated temp of the fluid in the middel of the coil have they
wonder why that is mad man you were very quick to reply to me about being oh so wrong about the humidity control and big pony about how i no nothing of this job and how i could
any one got answers or even a come back
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24-07-2013, 10:56 PM #79
Re: saturated conditions in a receiver tank PROVE ME WRONG
Read what I wrote, compression ratio. Do you know what this is!
It is not the change in liquid line but suction line.
I have not seen R12 for close to 20 years, so why would i even consider it. Was in not me who introduced glide in to the equation, so I think your assumptions are wrong. as per normal.
at 27 years old you are a slow learner then.
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24-07-2013, 11:00 PM #80
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24-07-2013, 11:02 PM #81
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24-07-2013, 11:12 PM #82
Re: saturated conditions in a receiver tank PROVE ME WRONG
you wrote
on a supermarket the liquid sub cooling cooling is normally done by the medium temp rack REALLY or even an economizer, which in simple terms have a lower compression ratio to that of the freezer.
YEAH SUCTION AND DISCHARGE PRERSSURE ARE CLOSER TO ONE ANOTHER DUE TO THE HGHER BACK PRESSURE
did you read what you wrote ALSO
Plus sub cooling reduces the required mass flow, to the evap to meet a specific duty, which can also reduce the the size of the piping between the the cabinets and the rack.
sounds to me like your talking about the liquid line right above this sentence
well im only 27 and ive seen quite abit of it, so it shows how often your on the tools does it not?????
plenty of container reefers are floating around with r12 still in them, was it not me who said yeah 0.5 k glide so really very little concern in this instance remeber near azetrop
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25-07-2013, 12:00 AM #83
Re: saturated conditions in a receiver tank PROVE ME WRONG
Did i say liquid line I said pipe sizing, more than one pipe.
Compression ratio reduction, equals increase in efficiency, hence saving the client money in running costs. Do you need to be spoon fed?
You have seen nothing, the world of refrigeration is massive. Why would I fix reefers, when you do?Last edited by Peter_1; 25-07-2013 at 07:07 PM.
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25-07-2013, 12:09 AM #84
Re: saturated conditions in a receiver tank PROVE ME WRONG
yeah alright you really are mad,
i tell you what ill send fieldpiece a critical email and let them know the ****** who writes his own pt chart says there insruments are wrong and simply cant be used to measure a fluid in a pipe with any sort of accuracy as we get huge temp differences when placing two sensors on either side of the 1 1/8 pipe the fact that there is maybe 0.1 to .3 k diff across the readings of the two sensors stiil means the the middel of the pipe is and must be much much higher in temp as copper is a very crappy thermal conductor one of the worst probaly....
you wrote mad fridgie;
The same with your measuring methods, therefore you can not support your arguments your data is flawed.
There is a saying "shyte in -shyte out" because your raw data is shyte, then so is your assumptions.
you cant answer my question on why use a pt chart to set a txv can u, u just ignor that statement,
you also ignor my statement on turning fans off and placing probe in middel of coil and it will read the temp displayed on your gagues
dont you, u havent brought that up have u, cause that is directly contradicting all the verbal diarrhea spewing from your mouth...
you all say the chart is pointless and u say my measuring methods are flawed, u all really need to pull your heads in, as the whole world measures refrigerant like this do you think danfoss place probes in there pipework when setting there own txvs no its accebtable to have a probe on the outside of the pipe even more acctable to insulate probe area.....
you do realise temp measurement is the average rate of collision of molecules right, average being main word so all measurements of heat are flawed no sensor will ever work the way you want it to, how could it, its not measuring every single individuals molecules temp and i will never be able to measure every droplet of liquid in the liquid line
i wouldnt care if i seen a few bubbles
but when a bulk subcooled liquid flows through a sglass and u see no bubbles, then i turn the donks off and half the glass is full of massive bubbles while the temp of the liquid stays the same the whole time,
and my gauges display its subcooled the whole time....
then i turn donks back on and sglass fills up straight away all while the liquid temp stayed constant.
and the final answer u give me as to why this happens is... you measured it wrong
you cant explain it, remember i am simply copying the only temp measurment method that all of you have used your whole life
........stop thinking about it in your text book explantions simply because you cant explain what the viods in the liquid is by way of your knowledge.
lets all chuck our digi temps out with our pt chartsLast edited by Peter_1; 27-07-2013 at 09:07 PM. Reason: Post contains insults
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25-07-2013, 01:22 AM #85
Re: saturated conditions in a receiver tank PROVE ME WRONG
Just because this is the only method you know, does not mean this is the only method!
The average is correct of the pipe and its surroundings, the point you clearly miss. Is it good enough for practical refrigeration of course, but for detail it is not (and the questions you ask are about the detail). That is why when require accuracy we use various pockets, low mass sensors, sensors with limited range, thus increased accuracy and repeat-ability.
How do I know that your testing is flawed, because i too asked the same questions, but instead of being rude to those who help, i built a test rig worth well over $100,000.
let me explain about normal temps sensors, they are round, the pipe is round, so your contact point is minimal, so the rest of the probe surface area is effected by what ever is around.
The probe has mass, as does the pipe, so even though see a pressure change, there is lag between this change and changes you see in a temp probe. "thermal mass"
Then when you change form a flooded pipe (high internal thermal mass) to a pipe that has vapour in it has low thermal mass, and reduced thermal properties, then the external forces will cause a high incident of error.
When you learn some respect I will assist, but for now, you suffer in your ignorance.
Saying that let me be the first to wish you a merry christmas. I hope that santa brings you a personalityLast edited by frank; 25-07-2013 at 06:50 PM.
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25-07-2013, 02:33 AM #86
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25-07-2013, 02:45 AM #87
Re: saturated conditions in a receiver tank PROVE ME WRONG
Only you say a PT chart is useless, your testing methods are for in depth knowledge. So knowing how to measure means that you can use PT chart correctly.
Why do you get the correct temp in the middle of a coil, read what I have said. The middle of a coil is effectively a pocket and is surrounded 100% by the refrigerant mass, will little influence of the ambient, not the same as a probe on the pipe, which is influenced, as proven if you wish to read.
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25-07-2013, 02:49 AM #88
Re: saturated conditions in a receiver tank PROVE ME WRONG
Thanks MG Pony, it is an industry we can always learn, which is good, and it is good to ask questions and even question ourselves, but part of being a good fridgie is being able to communicate with others. Our Aussie mate has not yet learn this important part of the industry.
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25-07-2013, 06:30 AM #89
Re: saturated conditions in a receiver tank PROVE ME WRONG
Haven't read all the posts, just posting this after the 2nd page: the PT chart is for a steady state system.
In a real life system, the flow also has a serious amount of kinetic energy incoporated in its flow, acting completely different than a steady state system. In the total energy is a serious amount of kineteic energy and everywhere where you decrease area (p.e. sight glass), flow will therefore increase and static pressure will decrease (Bernouillie principle) So P/T chart is then no longer validLast edited by Peter_1; 25-07-2013 at 06:33 AM.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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25-07-2013, 06:32 AM #90
Re: saturated conditions in a receiver tank PROVE ME WRONG
And measurements taken on the outside of a tube is never correct. Measure once after the TEV or at the 1st bend of the evaporator. You should see normally 'Te' but you will notice differences of 2 to 4 K, all dependend how good your probe contact is with the copper.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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25-07-2013, 07:48 AM #91
Re: saturated conditions in a receiver tank PROVE ME WRONG
I think he is looking for a promotion "Public Relations Manager"
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25-07-2013, 08:05 AM #92
Re: saturated conditions in a receiver tank PROVE ME WRONG
Proof,
patents, sale of IPs, commercialization, peer review. (practical and theoretical engineers)
If i am a f****** idiot, then so are those who I trained, sold to and purchased from, because I ain,t that good to pull the wool over everyone's eyes.
This site has many experts in many fields, because no one knows every thing, so your response only shows how insecure with your own knowledge base.
Much of what we believe we know is not true, but if we knew which parts then we would not believe.
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25-07-2013, 08:10 AM #93
Re: saturated conditions in a receiver tank PROVE ME WRONG
On another thread I compared you to Dt larca as you seemed to show similar attributes. It is now patently clear I have done a grave injustice to DT. From your unhinged ranting (with more than a hint of racism) you are not anywhere near his level of wit or humour let alone technical ability.
I am surprised and more than a little disappointed the mods have not acted in a more appropriate manner by banning you considering we are an international forum and welcome all creeds and colours..Last edited by frank; 25-07-2013 at 06:54 PM.
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25-07-2013, 11:44 AM #94
Re: saturated conditions in a receiver tank PROVE ME WRONG
well said Richard, i am surprised this P**** doesn't get beaten up by every person that meets him. I can imagine he is a pleasure to work with. I did notice whilst telling us all how great he is, he didn't mention what other techs think of him. (i'm sure he will though)
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25-07-2013, 11:52 AM #95
Re: saturated conditions in a receiver tank PROVE ME WRONG
.
I'm surprised this thread is still open and rjsinoz has not been reprimanded.
I have read this thread from the first post and I could not believe the hostility
in rjsinoz's posts and he reminded me of DT, like you Richard.
I have kept away from commenting (until now) because I could not weigh up
rjsinoz and I gave him the benefit of the doubt, but his post (or rantings) have
descended into personal abuse and racism.
I'm tempted to just block him (I would have done it earlier but can't remember how)
but there is an underlying problem with him if he comes onto a forum, makes a few
statements and then turns nasty because people don't shout how fantastic he is.
If you ever take advice rjsinoz, take this bit
Calm down, take deep breaths and re-read all the posts from the beginning. you might
be surprised to see that originally people were talking and offering advice but it was
you who was dogmatic in your approach and opinion that only you were correct and
every one else was wrong.
When this was pointed out to you, you then went on a personal attack and started
hurling personal insults out at almost everyone.
You might know some answers to a few things and you might be willing to learn, so
stop this arrogant, racist, insulting behavior otherwise your time on here will be
short and unpleasant.
Regards
Rob
... ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..
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25-07-2013, 01:57 PM #96
Re: saturated conditions in a receiver tank PROVE ME WRONG
I just noticed now these thread. I do not have the time these days to sit behind my computer oher than making invoices. I even read only the first 2 pages and some of the posts on the 5th page before making my statement.
It's sometimes difficult to judge how far one is going in insulting someone in another language.
I gave him the opportunity to edit his posts and perhaps previous post needs to be edited as well.It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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25-07-2013, 06:56 PM #97
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25-07-2013, 08:37 PM #98
Re: saturated conditions in a receiver tank PROVE ME WRONG
It's impossible to make anything foolproof because fools are so ingenious...
Don't ever underestimate the power of stupid people when they are in large groups.
Please, don't teach me how to be stupid....
No job is as important as to jeopardize the safety of you or those that you work with.
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25-07-2013, 09:41 PM #99
Re: saturated conditions in a receiver tank PROVE ME WRONG
an old saying here is you can't help some on who is unwilling to help them self. I am all ways game for furthering ones grasp of their field, half the fun in refrigeration is all the neat new stuff you learn while doing it! On one of josips threads I learnt I was wrong with how I understood amonia and aluminium work togeather! some times it is hard for others to let go of their preconcieved ideas and treat it as an emotional attack rather then some one volunteering their hard earned experiance to help us on the right path!
when I look at the title in hind sight, the way it is titled lends towards he wasn't here to learn hence why I said only he could prove him self wrong, all we can do is lend out or grasp of it!
It is unfortunat he wasted this oppertunity, I hope he gets over the issues and comes back in a more responsive way to learn from the volumes of knowledge the users here posses! It has helped me along greatly. So on his behalf I thank all of you for your shared knowledge!Now in Redvers Sask.
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25-07-2013, 09:48 PM #100
Re: saturated conditions in a receiver tank PROVE ME WRONG
Mods, you are doing good job.