PDA

View Full Version : Anybody seen anything like this before?







buddy
10-04-2012, 10:27 PM
Hi Guys,

I thought you might be interested in this, please look at the attached photos.

Have you ever seen anything like this before?

Its a home made small oil reservoir installed on a supermarket compressor rack/pack which I have placed a pen next to for scale purposes.

The reason the contractor said he manufactures his own oil "reservoir" is cost saving but I can see so many problems with this.

For starters -

1. Too small for correct volume of back up compressor lubricating oil.
2. It is a low pressure oil system and no differential oil check valve fitted to automatically discharge to common suction header.
3. Hot discharge gas could heat up the hall effect sensors on the Traxoil oil level controllers so they fail.

Any comments from you guys?

install monkey
10-04-2012, 10:34 PM
hi buddy- where did you get that big pen from haha- if the contractor manufacures/ installs these then you need to ask the question- have you lost any compressors due to lack of oil return?
he has fitted these oil resevoirs previously on other systems
the isolating valve is to regulate the pressure from the liq line to force oil back into the sumps but not to affect system performance by short cycling- if it works and the sight glasses show oil then assume all is well

buddy
10-04-2012, 10:40 PM
Hi install monkey,

The pen was a freebie from Bitzer (-:

Yes compressors have been lost due to oil issues on many compressor racks these have been previously fitted on and also overheating of the Traxoil oil level controllers.

The compressor oil always is a very dark brown after a period of time when these home made oil reservoirs are fitted also (you might just be able to see the colour of the oil in the photo of the Traxoil regulator).

install monkey
10-04-2012, 10:52 PM
as im more ac than packs- does the system pump down on setpoint if so there should a LLSV on the line off the oil seperator to stop it frequent cycling when pumped down?- if it has lost compressors,then what do the manufacturers recommend for size of oil reciever? -is there a common oil line between compressors-not done anything on oil level controllers-dont have em on daikins/mitsi

monkey spanners
10-04-2012, 10:54 PM
Diagnose it faulty and fit one you do like.

Usually they are vertical jobs with a couple of level sightglasses in, can't see much storage room in that doodad...

I don't work on packs though so am no expert... :D

stufus
10-04-2012, 11:01 PM
Don't do much on them either but that looks more like a buffer to me as the oil level regulators are self controlling ,just connected to the receiver for return and separation.

Cheers
Stu

buddy
11-04-2012, 01:30 AM
as im more ac than packs-
does the system pump down on setpoint if so there should a LLSV on the line off the oil seperator to stop it frequent cycling when pumped down?- if it has lost compressors,then what do the manufacturers recommend for size of oil reciever? -is there a common oil line between compressors-not done anything on oil level controllers-dont have em on daikins/mitsi

In answer to your questions -

1. No the system does not pump down on setpoint.

2. The compressors cycle on and off according to load requirements controlled by a Dixell pack controller.

3. And no common oil line between compressors.

4. The compressor manufacturer would recommend a higher volume/size of oil receiver.

buddy
11-04-2012, 01:34 AM
Don't do much on them either but that looks more like a buffer to me as the oil level regulators are self controlling ,just connected to the receiver for return and separation.

Cheers
Stu

Hi Stufus,

I dont know what you mean by a "buffer" as I have never heard of one installed on a compressor rack, please
explain?

The home made oil device is installed directly in-line between the oil separator and the Traxoil level regulators.

mad fridgie
11-04-2012, 04:36 AM
Looks like a glorified to tee to me,
Only driving force is when the float is open.
So the comp can be short of oil, oil sep is not full, no flow to the comp! (unless I am missing a pipe some where)

buddy
11-04-2012, 05:38 AM
Looks like a glorified to tee to me,
Only driving force is when the float is open.
So the comp can be short of oil, oil sep is not full, no flow to the comp! (unless I am missing a pipe some where)

Dear Mad Fridgie,

Good description a "Glorified Tee" ha ha.

No there are no more pipes, what you see is it!

The system is one pipe feeding oil from the oil separator through the oil filter then oil sight glass into the oil device where it splits up into 2 or 3 depending on how many compressors fitted.

You are correct, the only driving force is when the oil separator float is open.

Also if the oil separator float did ever stick open hot gas would flow straight to the Traxoil level controllers and bye bye compressors.

supermarketguy
11-04-2012, 10:08 AM
Hi Buddy,

Who is the manufacturer?

How many compressors on pack?

Do the 1/4" pipes that are in the resovoir, go all the way down or are the situated at the top of the resovoir. I would have thought oil feed to be on bottom of resovoir, so that only oil going to compressors and I would have expected, as in most resovoirs. That they would have fitted a prv on the tank to alleviate any pressure/discharge gas bulid up and allow this gas to dump into suction. most manufactures fit a 20 psi diff valve on their resovoirs. This stops hot gas reaching the compressors. From the photos, it looks very undersized.

Supermarketguy

750 Valve
11-04-2012, 01:20 PM
The way I see it the setup is all wrong.

1. Oil sep has an internal float - not a good setup on a rack, if the float fails you need to change the entire separator - unnecessary downtime. I would rather see an external float on a low pressure oil system
2. as mentioned the oil reservoir is crude, given its only a 2 compressor suction group the volume may be sufficient but I wouldn't trust it
3. no pressure differential between reservoir and crankcase - yes there is a pd when the traxoils initially open but after the pressure in the reservoir equalizes with the crankcase of the comp calling for oil you really rely on the separator's internal float opening to provide continuing pd. This is no different to a standard low pressure system except the reservoir has additional volume and is mounted above the crankcases. As others have mentioned hp will build up in the make shift reservoir - I think they are relying on this to force oil into the traxoils, if they did fit a 20psi check valve the pd would drop off very quickly and not force much oil into the traxoils.

I personally prefer a high pressure oil system, traxoils work really well with a high pressure differential. Typically in Australia we run an oil separator with inbuilt reservoir, out of the sep through an oil filter and then to a header pipe, through a ball valve feeding each compressors traxoil. No fuss, no hassles.

aramis
11-04-2012, 02:25 PM

1. Too small for correct volume of back up compressor lubricating oil.

2. It is a low pressure oil system and no differential oil check valve fitted to automatically discharge to common suction header.

3. Hot discharge gas could heat up the hall effect sensors on the Traxoil oil level controllers so they fail.

Any comments from you guys?

Point 1 also implies that oil may log inside the oil separator.

Point 2 also implies that once a solenoid opens to feed one compressor while the separator closed, there may be oil but not enough pressure in the collector to feed the second compressor. It would have been better if installed 2m above the Traxoil level.

Lack of sight glasses makes oil logging in the system hard to diagnose before the Traxoil stops the compressor.

buddy
11-04-2012, 04:18 PM
The way I see it the setup is all wrong.

1. Oil sep has an internal float - not a good setup on a rack, if the float fails you need to change the entire separator - unnecessary downtime. I would rather see an external float on a low pressure oil system
2. as mentioned the oil reservoir is crude, given its only a 2 compressor suction group the volume may be sufficient but I wouldn't trust it
3. no pressure differential between reservoir and crankcase - yes there is a pd when the traxoils initially open but after the pressure in the reservoir equalizes with the crankcase of the comp calling for oil you really rely on the separator's internal float opening to provide continuing pd. This is no different to a standard low pressure system except the reservoir has additional volume and is mounted above the crankcases. As others have mentioned hp will build up in the make shift reservoir - I think they are relying on this to force oil into the traxoils, if they did fit a 20psi check valve the pd would drop off very quickly and not force much oil into the traxoils.

I personally prefer a high pressure oil system, traxoils work really well with a high pressure differential. Typically in Australia we run an oil separator with inbuilt reservoir, out of the sep through an oil filter and then to a header pipe, through a ball valve feeding each compressors traxoil. No fuss, no hassles.

Hi 750 Valve,

Good comments and I do not trust it either.

We call the oil separator with inbuilt oil reservoir a "combination oil separator"...and its a high pressure oil system.

Dont really understand your meaning when you say an external float on a low pressure system as all the low pressure oil seps I have have worked on had internal float mechanisms which are either hermeticaly sealed (you have to change the whole sep if a problem with the float) or there are accessable types where you can change the float mechanism only (please see attached file).
8779

buddy
11-04-2012, 04:21 PM
Point 1 also implies that oil may log inside the oil separator.

Point 2 also implies that once a solenoid opens to feed one compressor while the separator closed, there may be oil but not enough pressure in the collector to feed the second compressor. It would have been better if installed 2m above the Traxoil level.

Lack of sight glasses makes oil logging in the system hard to diagnose before the Traxoil stops the compressor.

Good points Aramis.

THE DUDE
12-04-2012, 11:13 PM
I have seen a similar Resivor set up ( not as small tho ).The thing that conserns me is the small volume of oil, if the Seperator isnt feeding and a Trax is calling...there goes your Differential pressure. The Trax can handle high Differential pressures so a OCV shouldnt be necessay, but why there isnt a typical Oil resivor on there is beyond me? He must of had some Copper laying around and decided to use it.

750 Valve
13-04-2012, 01:06 PM
By low pressure I mean that oil downstream of the high side float (whether mounted internal of the separator or external) is not at discharge pressure - it is usually at a pressure above crankcase pressure determined by the non return (check) valve between the oil reservoir and suction header - commonly 20psi on installations found in australia.

By external float I mean a high side float that is not integral to the oil separator, the oil that is removed from the separator is under high side pressure until it is bled through the high side float which is mounted external to the separator, the float is mounted between the separator and the inlet to the reservoir - it is a lot easier to change a HSF mounted externally to the oil sep as there is only a need to isolate the oil line after the separator and the oil into the reservoir, the system can be left in operation if the appropriate isolation valves are present.

Below is a link to a manufacturer of external floats for a low pressure oil system.

http://www.temprite.com/product.asp?category=OIL_MAN&product=orf

buddy
16-04-2012, 03:00 AM
By low pressure I mean that oil downstream of the high side float (whether mounted internal of the separator or external) is not at discharge pressure - it is usually at a pressure above crankcase pressure determined by the non return (check) valve between the oil reservoir and suction header - commonly 20psi on installations found in australia.

By external float I mean a high side float that is not integral to the oil separator, the oil that is removed from the separator is under high side pressure until it is bled through the high side float which is mounted external to the separator, the float is mounted between the separator and the inlet to the reservoir - it is a lot easier to change a HSF mounted externally to the oil sep as there is only a need to isolate the oil line after the separator and the oil into the reservoir, the system can be left in operation if the appropriate isolation valves are present.

Below is a link to a manufacturer of external floats for a low pressure oil system.

http://www.temprite.com/product.asp?category=OIL_MAN&product=orf


I understand now what you were talking about.

Thanks for the clarification.

buddy
16-04-2012, 03:04 AM
I have seen a similar Resivor set up ( not as small tho ).The thing that conserns me is the small volume of oil, if the Seperator isnt feeding and a Trax is calling...there goes your Differential pressure. The Trax can handle high Differential pressures so a OCV shouldnt be necessay, but why there isnt a typical Oil resivor on there is beyond me? He must of had some Copper laying around and decided to use it.

The guy wanted to get the rack manufactured as cheap as possible that's the reason for this mickey mouse oil device.

He also installed the the same compressor rack without suction line filters.

Cheap with components missing, less labour cost etc.

mark thomas
17-04-2012, 07:15 PM
recomend to customer that oil res needs upgradeing or compressors will continue to fail and we all no that a larger oil res is a lot cheaper than replaceing compressors, ball is in custemers court then.