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faryuki
03-05-2007, 05:24 AM
Dear Guys,

I have running flake ice machine. The system is used ammonia flooded system. Recently the capacity could not reach 20 ton/ day (design condition), i have done for adjusment liquid level and also opening of expansion valve.
Any body have an idea and experience for this case?
Please kindly advice.

Many thanks

setrad7791
03-05-2007, 05:29 AM
Hi there! Have you checked your cutting blade adjustment? Im assuming your running a marja or howe ice machine. Just check to make sure the blade is scraping of every revolution and not running around 2-3 times before dropping ice off. Hope this helps... If you have any more questions please provide model type and application. i.e marine/factory based unit/water or air cooled condensor. Can you also provide type of ice-machine?

chillin out
03-05-2007, 06:12 PM
Recently the capacity could not reach 20 ton/ day (design condition),
20 tons of ice a day!!!!

Wow thats a big ice machine.

Any chance of posting a couple of pictures of it?


Chillin:) :)

US Iceman
03-05-2007, 07:10 PM
HI faryuki,

Since this is a flooded ammonia system several things come to mind.

The hand expansion valve should only be adjusted to maintain the liquid level in the surge drum. If you have mechanical float switches controlling a liquid line solenoid valve then I normally adjust the hand expansion valve so that the time to fill the surge drum to the operating liquid level takes about 3 minutes. At full capacity the solenoid should re-open in about 2 minutes.

If the surge drum liquid level is maintained by a low-side float valve the cartridge in the valve could have a restriction reducing the flow of liquid ammonia.

If the liquid ammonia level is being maintained the unit should produce the rated capacity.

If not, then you have to check for oil in the ice maker or surge drum. Have you drained oil out of either one of these lately. If not, the oil displaces the liquid ammonia and reduces the heat transfer.

If you have a back-pressure regulator on the surge drum is it properly set?

Have you checked the liquid line strainers upstream of the solenoid or low-side float valve? Any restrictions could reduce the liquid ammonia flow also.

The last thing I can think of is the inlet water temperature to the ice maker higher than normal? This reduces the ice machine capacity.

Andy
03-05-2007, 08:37 PM
20 tons of ice a day!!!!

Wow thats a big ice machine.

Any chance of posting a couple of pictures of it?


Chillin:) :)

North Star make a 30 ton machine, we look after a site with two of these on a 200 ton ice bin:D

The problem maybe salt content or lack of it in the water, or higher than normal water temperature onto the ice maker or simply short of gas.

Kind Regards Andy:)

Peter_1
04-05-2007, 06:49 AM
Setrad, is Maja or Howe making NH3 machines?
Both machines have a rotaing horizontal refrigeration circuit where for example a Geneglace has a vertical rotating water circuit

Peter_1
04-05-2007, 06:52 AM
Perhaps I can add to the possible causes: is the machine and more specific the generator evaporating at the same temperature as before?

I should go for excessive oil in the drum like USIceman said.
And why doubt the word of USIceman:p

US Iceman
04-05-2007, 03:43 PM
Peter raised a good point. I forgot to mention the evaporator pressure. This could be different for two reason: a back-pressure regulator is used and the set-point has been changed for some reason, or, the operating suction pressure has changed for some reason.

My first impression is to suggest checking to see if the oil has accumulated in the ice maker or surge drum as this is the most probable cause.

Josip
04-05-2007, 09:46 PM
Hi, Faryuki :)


Dear Guys,

I have running flake ice machine. The system is used ammonia flooded system. Recently the capacity could not reach 20 ton/ day (design condition), i have done for adjusment liquid level and also opening of expansion valve.
Any body have an idea and experience for this case?
Please kindly advice.

Many thanks

All above mentioned could be a source of your problem;)

What is your evaporating temperature in that system?

Best regards, Josip:)

faryuki
07-05-2007, 02:08 AM
Hi, Faryuki :)



All above mentioned could be a source of your problem;)

What is your evaporating temperature in that system?

Best regards, Josip:)

Hello guys

Before, thank you for your kind advise.
This is a new ice flake machine, use geneglace maker. Recently I already try to make adjusment for the blade to make the thicker ice from 1.9 to 2.1 mm and also the salt content from 40% to 60% and we have capacity (before) from 15 ton/day to 18 ton/day. At this ice machine we cannot adjusment the speed.
For evaporating temperaute is -28 degC

many thanks

yuhonghai
07-05-2007, 04:34 AM
hi,do you have the same water supply temperature as the design condition?This will cause the change of the ice capacity.

Peter_1
07-05-2007, 06:57 AM
Ohhh, a Geneglace, in fact my favorite machine.
We installed once _ I guess around 1988 - at that time the biggest one Geneglace ever had delivered to Belgium: 7.5 ton/day.

If you increase the ice thickness, then this can drastically decrease your total production capacity.

Have you looked once already in the rotating water reservoir inside, the flat one with all the small holes in it? These machines are prone to choke up with small lime pieces.If some holes are blocked, then this will also reduce your production.

Then, you're speaking about a salt content of 60%??? The more you add salt, the more the machine will encounter difficulties with generating ice.

And BTW, water of 60 % is almost unfreezable.

As far as a I have seen and used it for myself, the only time salt solution was added was to improve the ice removal from the cylinder. The flakes coming of the generator are then also a lot bigger.

You sometimes see a small plastic tube at the outside of the Geneglace wherein you have to slide salt tablets.

A better way is to make install a small drum with salt in it and a float which holds a certain water level in it.
The salt will melt till its maximum density (I think +/- 28%) where the rest of the salt remains unmelted in the water and this salt solution is then added with a small pulse pump direct in the rotating water reservoir inside the machine.http://www.oilegypt.com/webpro1/DBimages/6_1_MAGDOS20DE20DX.jpg

Josip
07-05-2007, 10:27 AM
Hi, Faryuki :)


Hello guys

Before, thank you for your kind advise.
This is a new ice flake machine, use geneglace maker. Recently I already try to make adjusment for the blade to make the thicker ice from 1.9 to 2.1 mm and also the salt content from 40% to 60% and we have capacity (before) from 15 ton/day to 18 ton/day. At this ice machine we cannot adjusment the speed.
For evaporating temperaute is -28 degC

many thanks

Take a look on attachment hope to be of some help to you ;)

Best regards, Josip :)