ABS pipes

[spr2003]

Is anyone on here experienced with ABS plastic pipes? I think we are in a big trouble. We made 14 months ago a plant for hipermarket with secondary fluid and piping in ABS Coolfit (preisulated) by George Fisher. Diamenters from 6" (160 mm) down to 1 1/4 (40 mm) Well, now we found two leaks of Hicool 40 from the low temperature plant.
Both from 3" (90 mm) diamter pipe. It seems leaks are from junctions. Big trouble is the plant can't be stopped. We are still waiting for technicians from GF from GB or Sweden, i don't remember.
Any advice is welcome.

[Brian_UK]

It seems leaks are from junctions. Big trouble is the plant can't be stopped.

Do you mean that the leak is from the joint at a "Tee" or "Bend" where the pipe enters the fitting ?

This option does depend on the pressure within the pipework but..... if you fill a hypodermic syringe with the solvent used to glue the joints together you may be able to inject it into the leak itself.

If it is at all possible to lower the pressure indside the pipework then the vacuum will 'pull' the glue into the hole.

[spr2003]

Do you mean that the leak is from the joint at a "Tee" or "Bend" where the pipe enters the fitting ?

This option does depend on the pressure within the pipework but..... if you fill a hypodermic syringe with the solvent used to glue the joints together you may be able to inject it into the leak itself.

If it is at all possible to lower the pressure indside the pipework then the vacuum will 'pull' the glue into the hole.

I have both of the conditions One is on a tee, and probably on a reduction for a smaller pipe diameter, and one is on a joint between two straight pipes. In the GF Coolfit, anyway, the manifolds and fittings are inside the pipe, and not outside. That cause on the external part the pipes already comes with thermic insulation.
About the glue, the ABS has a procedure like "welding" The glue is a solvent wich melts the plastics, and when it comes hard again, evaporating the solvent, the two parts becomes one only piece. But it takes 48 hours at +5°C min. We hardly have one hour time, with frozen food and ice creams. And trust me, in that place there is a lot of food. I'm told about half a million Euros.....
My dramatic doubt is: if the joints have been ok since 14 months, it means all the other joints can make the same, and we shall have a colander, instead of a hi-tech plant.
I'll post pics as soon as i will be allowed.

[Andy]

I have both of the conditions One is on a tee, and probably on a reduction for a smaller pipe diameter, and one is on a joint between two straight pipes. In the GF Coolfit, anyway, the manifolds and fittings are inside the pipe, and not outside. That cause on the external part the pipes already comes with thermic insulation.
About the glue, the ABS has a procedure like "welding" The glue is a solvent wich melts the plastics, and when it comes hard again, evaporating the solvent, the two parts becomes one only piece. But it takes 48 hours at +5°C min. We hardly have one hour time, with frozen food and ice creams. And trust me, in that place there is a lot of food. I'm told about half a million Euros.....
My dramatic doubt is: if the joints have been ok since 14 months, it means all the other joints can make the same, and we shall have a colander, instead of a hi-tech plant.
I'll post pics as soon as i will be allowed.

Hi spr2003

sorry to here about you trouble

We use GF pipe on glycol cooling circuits for banana rooms.
A few points we have seen.
1/ leaks at joints is usually down to a poorly made joint, either the glue was not applied properly or the glue was out of date.
2/ Fitting fracture. This can be down to two things, either the pump is coming off and on too harshly shocking the pipe, or the route chosen for the pipe leaves no room for pipe movement, (the terminal points are too close together or the pipe is cliped too well).

For a tempory repair you can use eletricians amalgamating tape (rubber tape that sticks to it'self) this will give you time to arrange an outage of the plant for a proper repair.

Kind Regards Andy

[spr2003]

Hi spr2003

sorry to here about you trouble

We use GF pipe on glycol cooling circuits for banana rooms.
A few points we have seen.
1/ leaks at joints is usually down to a poorly made joint, either the glue was not applied properly or the glue was out of date.
2/ Fitting fracture. This can be down to two things, either the pump is coming off and on too harshly shocking the pipe, or the route chosen for the pipe leaves no room for pipe movement, (the terminal points are too close together or the pipe is cliped too well).

For a tempory repair you can use eletricians amalgamating tape (rubber tape that sticks to it'self) this will give you time to arrange an outage of the plant for a proper repair.

Kind Regards Andy

Hi Andy, thanks for the quick answer.
On the joints i can't say anything untill i will see them in hands.
About the pipe mouvemente we did follow all the GF rules, leaving the right space to increase e decrease after the temperature effect with the right corners and angles.
For the pumps we start them with a soft start system by Siemens. We call it ramp starter. In effect we stop them three times s day for the defrost of the cabinets....
Thanks again
Regards
Sergio

[spr2003]

Now i can post a few pics.

http://img180.imageshack.us/my.php?i...6mediumrg0.jpg

http://img206.imageshack.us/my.php?i...5mediumpn3.jpg

http://img180.imageshack.us/my.php?i...4mediumcr6.jpg

http://img180.imageshack.us/my.php?i...3mediumge8.jpg

[Peter_1]

We used these and have no complaints about it. See pictures.
In these tubes, there's Thermera in it from Dehon (+/- 2.000 l).

Have you taken in account the very large expansion of these tubes, especially the long straight runs and with the very large temerpature range (30°C till -10°C I suppose, so a DT of 40 K)?

Your pumps are VFD controlled, so that's also not the reason.

You have a point if you say that they were tight for 14 months.

It takes indeed more then a day to cure these joints. There will be only one solution for this: installing a second line besides the first one and at the and, glue brass couplings on it.
Your client must understand this and that he also had to follow the technical rules for this kind of product, whatever times it takes.

[monkey spanners]

Have seen some couplers with a glue socket one end and a 'o'ring socket the other. could you make up a repair section, wait for the joints to set and then fit it in your one hour time slot with the 'o' rings sealing to you existing pipework? Might have been in a durapipe catalogue. We had a joint fail when an ice builder froze up solid on a dairy farm (leaky solenoid) pressure must have increased in the pipe work until something gave.. Will try and find the catalogue.

Jon

[spr2003]

The temperature of Hi Cool 40 inside the pipe is -28°C, so very low, and it grows up to 4/5 °C during the defrost. To tell the truth it defrosts with stopped pumps, but at the restart the Hi Cool liquid heated from the coils walks the pipes to the chiller and all the system takes a few minutes to get back to normal (-28°C).

Yes, we did take in account of the expansion of the plasic according with GF reccomandations.

Thank you all, guys, any advice is really welcome!!

[Paulajayne]

Hi

Test this first on a spare piece of pipe and fitting, but I believe that this is a thermosetting plastic and a temporary repair can be made with very careful use of a soldering iron.

I would use one fitted with a temp control and by testing on the spare pipe find the most suitable temp to use.

From the spare pipe / fitting make up a "Filler rod" and treat it as though you are welding.

Like all welding jobs ensure surfaces are clean.

Have a damp cloth to hand for cooling.

HTH

Paula

[Renato RR]

How high is pressure in pipe?What it flows thru it? brine?

Renato

[spr2003]

How high is pressure in pipe?What it flows thru it? brine?

Renato

The pressure is around 5 bar, and inside we have Hi Cool 40, a sort of glicole capable of very low temperatures. I don't now exactly what it is.
Today it's the day: we will have GF technician here since 10 am.
We shall see....... (crossing fingers)

Sergio

[Peter_1]

Share anyhow your experiences because those can aslo be important for us.

I'm doing some bets:
not enough measurements for expansion (you have a large DT) of the pipes; especially in 90° junctions.

Glue not spreaded uniformely or pushed away when assembling the pieces together.

The male piece has to be filed/sharpen under a big 45° angle. Was this allways done?

Not turning the male piece when you insert it for final assembling.

[spr2003]

Share anyhow your experiences because those can aslo be important for us.

I'm doing some bets:
not enough measurements for expansion (you have a large DT) of the pipes; especially in 90° junctions.

Glue not spreaded uniformely or pushed away when assembling the pieces together.

The male piece has to be filed/sharpen under a big 45° angle. Was this allways done?

Not turning the male piece when you insert it for final assembling.

We have been large with expansion meaures. About 150% plus from GF advices.

May be a bad glueing, but why after 14 months two leaks?

On CoolFit, the manifold is male, and fitted inside the pipe.

Absolutely no turns on the fresh joints.

Gf says it might be a fracture due to the weight of the pipe + liquid, but here also we have been less than what GF says on the distance between supports.

GF will deliver us a kit from Henkel, wich is a gauze to put on the pipe, and glueing it on many times, untill it is strong enough. They say it gets dry in half an hour in dry condition and ambient temperature.
We shall try the work next tuesday night, after the sale time.
I will do a lot of tics, of course.
Otherwise they have a mechanic axial restraint pipe coupling with rubber sealing, but to fit it you have to cut complitely the pipe first.

Cheers.
Sergio

[Renato RR]

Good old steel pipe.

Renato

[US Iceman]

Otherwise they have a mechanic axial restraint pipe coupling with rubber sealing, but to fit it you have to cut complitely the pipe first.

This sounds like a thrust block. If this is the case, then it would seem they suspect the problem is due to axial movement of the pipes.

The only way this could be happening is:
a) The pipe expansion is causing the pipe to move, or

b) When the pump starts, the pipe jumps and produces shock due to the sudden flow in the pipe, or

c) A control valve is quick closing valve and the sudden decelleration of the liquid causes a shock wave that impacts on an elbow or valve.

Any one of these could be considered a transient condition, i.e., it only occurs for a short period of time. However, the repeated frequency of these events may produce a failure after some period of time.

[Perseus]

Good old steel pipe.

There is nothing wrong with plastic pipe.


Attention to proper assembly procedures cannot be stressed enough.

[spr2003]

This sounds like a thrust block. If this is the case, then it would seem they suspect the problem is due to axial movement of the pipes.

The only way this could be happening is:
a) The pipe expansion is causing the pipe to move, or

b) When the pump starts, the pipe jumps and produces shock due to the sudden flow in the pipe, or

c) A control valve is quick closing valve and the sudden decelleration of the liquid causes a shock wave that impacts on an elbow or valve.

Any one of these could be considered a transient condition, i.e., it only occurs for a short period of time. However, the repeated frequency of these events may produce a failure after some period of time.

- The tollerance on extensions to avoid pipe and fittings damage is 50% more than GF tables (150% total)
- The pumps starts with a soft start device from Siemens.
- There are no valves on the plant. All the plant users defrosts toghether with stopped pumps.

Tonight we shall see. All the things are ready for the event. I will catch some rest now, cause i'm sure it will be a hard night.
I'll let you all know tomorrow.
Sergio

[spr2003]

Everything seems went good last night.