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rajgulati
04-06-2008, 12:09 PM
Hi everyone!

Can anyone had experience with spiral freezer.

Can we use Spiral freezer with nh3 gravity flow system instead of liquid overfeed system. Freezer is FMC make.
regards

Magoo
07-06-2008, 03:58 AM
Hi Raj
Yes the coil can be gravity fead, but needs a surge drum approximately 3.5 metres above coil, check that coil circuiting suits gravity feed. Go back to FMC Foodtech and discuss options and design.

Magoo

US Iceman
07-06-2008, 04:15 AM
I'm curious why you want to use a gravity flooded system instead of liquid overfeed. Are you changing this?

RANGER1
07-06-2008, 04:54 AM
Their latest design is gravity feed,but to change it would be like starting all over again.Big$$

US Iceman
07-06-2008, 04:30 PM
Why are they using gravity flooded Ranger1? It seems like a waste of good ammonia.:D

Andy
07-06-2008, 06:22 PM
Why are they using gravity flooded Ranger1? It seems like a waste of good ammonia.:D

Hello Iceman:)

they may call it gravity, but it is probably liquid overfeed using an injector and a high pressure liquid line (like the Mojo surup cooling plants). From memory FMC owns frigoscandia who developed this system, I think it is on the FMC web site.
Nothing new but a well applied old technology.


The advantages of this system are.

1/no pumps
2/smaller dry rather than wet suction returns.
3/No insulated pumped liquid lines needed.
Kind Regards Andy :)

RANGER1
07-06-2008, 10:42 PM
Andys description is right. liquid pumps were ok but severe on pulldown causes a lot of cavitation as well

US Iceman
08-06-2008, 12:57 AM
...liquid pumps were ok but severe on pulldown causes a lot of cavitation as well.


I've seen this occur also, but this is a design flaw and not the pumps fault.

RANGER1
08-06-2008, 10:56 PM
You could call it a design flaw, but it starts up hot every day and try to pull down to temp as quick as possible.
Liquid pump cant help but cavitate in most cases.
System Andy describes is cheaper,as no accumulator/liq pumps.
High pressure liquid line is insulated as system is usually single stage economized.Surge drum is in refrigerated place, so no need to insulate.I have worked on one new style breifly and hot pull down still has its problems if you load up comps to quickly (liquid carryover).

Rajkumar
10-06-2008, 06:24 AM
Thanks andy,

Pl. forward the sketch for the same.

Regards

Andy
11-06-2008, 09:23 PM
Thanks andy,

Pl. forward the sketch for the same.

Regards

www.fmctechnologies.com/upload/lvsfrigopakrefrigeration.pdf

Rajkumar
12-06-2008, 06:15 AM
Thanks Andy the literature is very useful.

Magoo
13-06-2008, 02:37 AM
Speaking from years of experince with these FMC systems, the first start on any day should be slow and easy, at least 1 hour before product enters spiral, pump feed or gravity or LVS, the same rule applies, PLC rograming should control the fact. LVS is far superior, but FMC/ Frigoscandia/ now JBTC, guard LVS to the extreme.
In short don't load compressor quickly on first start for day, and everything will go great.
magoo

Magoo
06-07-2008, 02:34 PM
You are all very quite on this topic/post.

magoo

ntfreezer
16-07-2008, 09:18 AM
you can link. www.worldbase.cn (http://www.worldbase.cn)