Hot gas defrost in NH3

[smpsmp45]

Recently we came across a situation wherein the Plate freezer plates were bending after a period of about 6 months operation.

After checking the system it was found that the HGD system was without any pr. reducing valve & hence Ammonia at high pr was entering the Plates & that resulted in bending of the plates.

The paper which I had posted earlier had clearly specified that pr. reducing valve upto 80 KG is a must in the HG line.

[Tycho]

Recently we came across a situation wherein the Plate freezer plates were bending after a period of about 6 months operation.

After checking the system it was found that the HGD system was without any pr. reducing valve & hence Ammonia at high pr was entering the Plates & that resulted in bending of the plates.

The paper which I had posted earlier had clearly specified that pr. reducing valve upto 80 KG is a must in the HG line.

what brand platefreezer is it?

the plates in our freezers are rated at 200 bar, and the design doesnt vary very much between different companies.

[US Iceman]

My first impression of this issue is not the pressure of the hot gas, but rather the factor of vapor propelled liquid in the hot gas line. This sort of issue can creta e a lot of energy that will bend metal (or break it) very easily.

My preference is to provide a means of draining the condensate out of the hot gas lines. If you do this, then the gas pressure does not have anything to do with it.

[smpsmp45]

Dear Us Iceman,

Your point is also important & we shall take note of that as well

[ntfreezer]

I agree with the US ICEMAN's ideas.