Leak detection

[Reeferjon]

A guy contacted me a few weeks ago with a diferent aproach to an old method of leak detection.
He is using ultra-sonics to detect leaks, but using a microP to analize the bubble size and strength in the liquid line, from a software model for a trained unit it can determine if the detected bubbles are what it expects having an accuracy of 3%!!!

The guy now wants to see if it can be adapted for Reefers, personaly I think the cycle would not be stable long enough to train let alone actualy run a a comparison.

[Brian_UK]

If I understand what is being suggested I would have thought that the method of counting bubbles (very simply put I know) would only work if you knew exactly what should be happening at any one time.

How does the machine decide when the system is properly charged in the first place and at what state (temperature/pressure) should the leak test be performed.

I would have thought that the 'basic' indicators, bubble solutions, pressure tests, leak sniffers, dyes etc would have been sufficient but am willing to be convinced otherwise.

[Reeferjon]

This is currently under dev. I have not seen one in action yet, but they tell us it works in the lab.
I get the impression that the system has to be 'trained' to detect a certain signitur for a given temp range.

I quite agree we live by soap solution, but we do not use LP switches so suffer from regular burn-outs.

[Brian_UK]

Originally posted by Reeferjon
...we do not use LP switches so suffer from regular burn-outs.

I suppose they consider the value of the product more than the equipment. It is cheaper sometimes to run the kit into the ground as long as the cargo makes it to the destination.

[Reeferjon]

well yes it, this is where we have our 'grey' area's eg topping up leaky systems with a loaded unit.
The load costs say £10K the cost of call out, lost time, reload & reshiping, then disposal of the wast all mounts up and of course the product begins to waste quite quickly in a 14M body.
So from that the engineer has to make a decision to fix of not, you are bad if you do bad if you dont.

We have today recieved the fist format written notification that we WILL not top off CFC or some HCFC even if supplied by the customer ( yes I know but some of our customers with LARGE fleets bought huge amounts of *****) when you concider the price of a 401 convertion can be upto 3K and the customer has 30 units he has a very big problem.

[Derek]

Helium

The only real answer IMHO.

High unit cost but huge savings in time and aggro.


Looked at ultrasonic units but background noise was the issue.

[Brian_UK]

Originally posted by Reeferjon
We have today received the first format written notification that we WILL not top off CFC or some HCFC even if supplied by the customer ( yes I know but some of our customers with LARGE fleets bought huge amounts of *****) when you concider the price of a 401 conversion can be upto 3K and the customer has 30 units he has a very big problem.

I appreciate that no-one likes to spend money especially when the supermarkets expect everything for free....but did they think that the gas usage problem would dissappear?

In practice then you have been breaking the law since January then Jon? How does it feel to be a criminal ?

[melted]

The engineer has to make the decision to top up a system,when out on the road there is nowhere to put goods that are melting out of the back of a trailer.
What do you do at 3am in the morning in summer with a load of frozen,and having just driven 1hr to get to the thing?
will the customer understand that he lost a load because the law said no topping up????and still get presented with a bill for ££££.

[Reeferjon]

Just to clear up we have not used CFC since OCT 00

No-where has it said until now (except CFC), thou shalt not top off a leaky system. Our interpretation is that as from Jan 2001 you cannot install CFC, sell CFC or service CFC. As for HFC?

[FreezerGeezer]

Originally posted by Derek
Helium

The only real answer IMHO.

High unit cost but huge savings in time and aggro.


Looked at ultrasonic units but background noise was the issue.

Hello Derek. I'm intrigued. Could you tell me more about this method?
Thanks.

[Derek]

Pressurise System (after proof test of course) with helium (medical grade with filter recommended)

Use mass spectrometer (£16K ish) and sniffer probe. Leaks to 1-2 grammes/year detected in seconds. No cleaning up of dyes or soapy water. Detects down to molecular level leaks.

Note leak testing under water can hide leak sites.

Place small system / suspect component in chamber. Vacuum chamber introduce helium to component measure with mass spectrometer and you have a total leak rate.

The chamber method is used by most domestic manufacturers. They also have helium recovery systems to cut cost.