Does anybody know what method is used to control the wear state (wall thickness) of "twin pipes" on concrete delivery line? What do they use in official service?

I always take a good look at the pipes when i change a rubber  I don't think you can measure the thickness from the outside with twin pipes..

take off the 90°'s look inside the pipes, and in de 90°

if worn off one-sided turn the pipe, turn the 90°. 

if the pipe is worn off egaly turn the pipe in length.

if the corner has "inside-pipe-damages" throw it away to the scrap-handler.

if there is "inside-pipe-damage" in the pipe throw it away. 

the outside-wall is soft iron and won't last long, you will be taking risks if you go on pumping with damaged inside pipes.

i have known insurances who have disclaimed damages because of "not housfatherly-like maintenance".

they said "you knew it was going to happen, but you did nothing to prevent it." 

Thank you guys for your advice about visual check!!! But did you see somebody using ultrasonic gauges to measure the thickness?

Some years ago my reducerpipe burst in the welding - the reducerpipe was wornout and through that small gap the concrete were highpreassure-spraying the whole front of a building. A totaly disaster!

But when i told my isurancecompany that i´ve done what has to be doned to avoid this accident, then they did not want to pay anything. The insurancelady explain to me that they only pay the accident if i knew, but didn´t care about if the reducingpipe will burst!!       I only talk truth! She told me that! 

So i explained to the insurancelady that i´m a careless human that don´t take care about my life and my equipment and start my pump even if i know that my reducerpipe will burst and cause an accident. It was only then she understand and have permission to pay the accident!!?

Don´t ask me how insurancecompany work - i did only say what the insurancelady beged me to say about how the accident could happend. My insurancecompany do only pay if i´m a careless idiot. The common sence is blown away. I don´t care as long they pay. 

Ha ha ) Looks like there could be a lot of funny stories concerned with insurance conmanies. Is it true?

Ohh, sorry, I meant "companies". I make a lot of typos writing on internet from mobile phone...

You can't measuer twinwall with a ultrasonic gauge . Only singelwall pipe .

i am with vasa on this one

Actually, Vasa, I have seen one fancy ultrasonic gauge with a graphic display. This device is approximately the same size like a smartphone and it is able to catch the full thickness of twin pipe when you have a filler (for example, concrete) between the two layers of steel. The secret is that this device can analyze the readings of different materials on its way and choose the maximum one... Only one thing made me upset - is the price approx 2000 USD.

"thickness of twin pipe when you have a filler (for example, concrete) between the two layers of steel" If You have Concrete between the two layers of steel than You have a problem , it's time to change the pipe ! But if You show Me what brand the ultrasonic device have so I can look at it and see IF it's true We buy one . 2000 USD is not that much . If one pipe blow in the wrong place 2000 is not much . How much Does Your pump cost ? How much money does it bring in every week ? You must have 2000 left to buy one ? How much does a pump cost ? When You buy one new tell the salesman that You want one ultrasonic that you talking about .

I agree with Vasa 2000USD is not a big deal for something like this.

I agree with Vasa and gavros! The price is not that much! But also I realized now that not all the pipes have "filler" inside. On the picture attached you can see 2 kind of bends: one has some filler between the steel layers, and the second one has not. Suppose that we can say that all the straight pipes have an air gap between the layers of inner Hard steel and outer layer. Usually the bends have this gap, but in some cases - not: the gap is filled in factory with some polymer or it is naturally filled by concrete, coming into the gap through the special holes during the first pour. Speaking about an ultrasonic method, it is true that even a thin air gap between layers is a critical barrier that cannot be overcomed by ultrasonic waves... That is the limitation for this method. Looks like it is not possible yet to cancel the operator`s duty to take care about the wear state of concrete delivery pipelines!

Vasa is the man, i know him!

Yuri

As the former Esser Sales guy here in the US I wanted to let you know that the pipes are not at all like the elbows. The elbows with the "filler" material are the 900 series and that material is there to help absorb some of the impact and shock from falling concrete when the pipeline system is angled all goofy.

The pipes have no gaps between the inner and outer walls. That doesn't matter if you are buying Esser or CF twin wall pipes or anyone else for that matter.

Lastly there is no ultra-sonic tester that is capable of giving an accurate reading on twin wall pipes without a special tip on the reader. The best thing to use in the case of measuring the pipes and elbows is a caliper that allows you to reach inside the pipe and for you to take the measurement of the total wall thickness.

If you have any questions feel free to send me a message and I will do what I can to help you.

Best regards

Will

The only way I can figure how to guage wall thinkness & wear of dual wall system is to weigh each pipe individually..

 How much does a new dual wall 3m pipe weigh??? 

The best way we have found to test the twin walls is with elctronic calipers. We do this by measuring the inlets and outlets of each pipe. Taking the reading for the top, bottom, left and right of each outlet and inlet.