Help needed on blasted cold store doors

[Hakan]

We have a 10 room ULO cold store (cooling & ulo units from Van Amerongen) each room with 100tons capacity. We commissioned last year and we are storing apple.

We have a weird problem that we are dealing since last year and still could not find the cause and solution.

Last year door of one of the cold store rooms literally blasted off damaging the insulation panels(walls) inside and door fell down, following next week same happened to another room.

This summer we invited service and they checked everything (please note that rooms were empty) and told us everything is in order.

Now this year we began harvesting and again the door of another room blasted after we put apples inside and we were using ventilation, humidifier and cooling. No ULO at all.

Did any of you have seen or heard such a problem before? All the comments and help deeply appreciated.
15992

[Tayters]

The apples giving something off that in turn is pressurising the room? I see you mentioned you had ventilation going but just a thought.
Cheers,
Andy

[mbc]

Hi
You need air equalizing dampers systems
It happen when system comes off from defrost.
Put 5 minutes time between defrost and run time and frist inlet liquid comes one and later about 30 to 60 seconds fan comes one .

[Rob White]

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What MBC said :D

When a system goes onto defrost and then comes off defrost a pressure difference is caused because of a temperature difference. The extreme pressure rise can blow doors open or in your case off the runners. I have seen full wall panels blown out and roofs lifted off because of the pressure difference.

A simple air pressure equaliser vent in each room will sort the problem.

Rob

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[Hakan]

Dear Rob, thank you very much for your reply.

What kind of equilizing damper is needed? What should be the diameter and capacity? How can we calculate necessary diameter and capacity. Can you recommend any brands and models?

Thanks in advance

[knighty]

I know it looks/sounds like a bodge

but I've used 110mm plastic waste pipe out from the room with a U bend in it, fill with water (and a bit of bleach to keep it fresh)

and it's always worked great, had loads of problems with 'proper' dampeners before


also as above, timer for fan delay after defrost on the evaporators

or add a thermostat so there's fan delay until evap reaches X temp

[martinw58]

can your cold room manufacture can supply them

[martinw58]

look for fermod 2220 pressure relief valves

[Rob White]

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Ultimately the hole needs to have flaps on it to stop air movement when not needed.
The tubes tend to be about the size as a sewer drain pipe like Knighty says :)

If it is apple you are keeping cool then temperature difference should not be a problem.
The problems happen on freezer rooms and they need trim heater to stop them freezing closed.

Any cold room provider will supply them but ultimately they are just a hole in the wall :D

Rob

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