PHE evaporators

[Mataura]

Hi Everyone,

I'm new to this platform and feel privileged to be amongst you all.
I have just come across a flooded PHE evaporator used to remove heat from process cooling water reticulated at a dairy factory. What surprises me is this: there are no isolation valves between the suction accumulator/LP separator and the PHE which mean, whenever the PHE leaks the entire ammonia refrigerant charge needs to be decanted into a mobile storage tank as there is no ammonia receiver on site. Is this a common modern piping system these days or am I too old fashioned? I would really like to know your opinions. Thanks.

[RANGER1]

Mataura,
Welcome, I agree with you. but common practice in Australia.
Seen one just installed & liquid receiver not big enough to carry out pump down!
Sometimes difficult to fit in when you want compact skid 150-200nb valves etc.

[Mataura]

Hi Ranger1,

Thanks! Yeah it's just not something I'm use to, particularly working on NH3 in fishing vessels. If it can't be isolated, then it can't safely be worked on? Interestingly, the same company who installed this has identical setups but with isolation valves.

[RANGER1]

Mataura,
Fishing boat is a different story to me.
Sounds potentially dangerous.
Tycho would be best for that one.

[Tycho]

Mataura,
Fishing boat is a different story to me.
Sounds potentially dangerous.
Tycho would be best for that one.

it's all about the money, when you think about it most of the valves are there for isolating for service.

Most contractors are usually kind enough to make their systems/plants service friendly.

Sometimes if the client has some basic knowledge of service and maintenance they will request additional valves which is probably why you are seeing identical units except with more valves.

[Mataura]

Thanks for your responses Tycho and Ranger1.

The fact there's only one compressor at this factory kind of says it all I guess. There was no money for isolation valves or a backup compressor.

[Grizzly]

Interesting observations Mataura. Lack of isolation Valves etc. Was a common fault.
However and I am not sure if its the same for your side of the world. But here in the UK as i was informed last Friday a 59kg cylinder now costs upward of £250.00. When I retired 3 yrs ago it was £80.00 ish.
If your prices are similar, there is a good argument for decanting and upgrading I would of thought. Or at least having those upgrades in "the back of the book" for the future. At least planting the seed with the customer shows what a professional you are.
That always bodes well for the future.
Good luck Grizzly