where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
1460 views
Technical Discussions
brent hughes
,
USA, Joined Jan 2016, 5

brent hughes

,
USA,
Joined Jan 2016
5
13:26 Mar-14-2016
Bubbles

I have a 100' long X 6' wide X 3' deep UT water bath tank. I have problems with bubbles forming on the test parts and the transducer. A wetting agent is not practical and cost prohibitive due to the tank cleaning requirements, and quenching solution heat treated material. I especially have problems in the spring and fall, due to the weather and temperature changes often and quickly.
Does anyone know at what temperature the water bath must be to keep bubbles forming?

1
 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1286

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1286
14:26 Mar-14-2016
Re: Bubbles
In Reply to brent hughes at 13:26 Mar-14-2016 (Opening).

Brent, bubbles will probably form at most temperatures that you are likely to be comfortable working in. The tank you are using is rather large! But the best option is to use de-aerated water. This will help reduce the available air that is dissolved in any tap-water. A wetting agent might help to allow the bubbles to release from surfaces, but the origin of the bubbles is still due to the water used to fill the tank. Make sure your filtration system is tight and not allowing any air to be drawn in during circulation. I used a much smaller tank in my earlier years in NDT and we had a constant water-supply being prepared by a reservoir tank that was equipped with a venturi tube that pulled air from the water (you could easily see the water bubbling as if it was boiling as the air was pulled out).

 
 Reply 
 
Volodymyr
Engineering, Deputy Director for Technical Issues/Head of Testing Laboratory/Chief of department/NDT
Joint Stock Company, Portugal, Joined Mar 2016, 25

Volodymyr

Engineering, Deputy Director for Technical Issues/Head of Testing Laboratory/Chief of department/NDT
Joint Stock Company,
Portugal,
Joined Mar 2016
25
16:51 Mar-15-2016
Re: Bubbles
In Reply to brent hughes at 13:26 Mar-14-2016 (Opening).


to nr.1

Hi Brent!
these methods:
1. Temperature: see Pic.
2. For example, removal of oxygen from water may be achieved by introducing it into sodium sulfite. sodium sulfite, when introduced into the water is oxidized by oxygen dissolved in the water to sodium sulfate:
2Na 2 SO 3 + О2 -> 2Na 2 SO 4.
3. Chemical reagent with which can achieve substantially complete removal of oxygen from water is hydrazine. When introduced into water and oxygen is the binding of an inert nitrogen excretion:
N2 H4 + O2-> 2H2O + N2.
 
 Reply 
 
Anmol Birring
Consultant,
Birring NDE Center, Inc., USA, Joined Aug 2011, 781

Anmol Birring

Consultant,
Birring NDE Center, Inc.,
USA,
Joined Aug 2011
781
23:46 Mar-15-2016
Re: Bubbles
In Reply to brent hughes at 13:26 Mar-14-2016 (Opening).

Try deionzied water. Keep the tank and parts real clean to minimize nucleation sites

 
 Reply 
 
Andrew Hurrell
Consultant, Ultrasonic Transducer Production
Precision Acoustics Ltd, United Kingdom, Joined Apr 2000, 25

Andrew Hurrell

Consultant, Ultrasonic Transducer Production
Precision Acoustics Ltd,
United Kingdom,
Joined Apr 2000
25
17:28 Mar-18-2016
Re: Bubbles
In Reply to brent hughes at 13:26 Mar-14-2016 (Opening).

HI Brent - you may be interested to note that the IEC ultrasonics committee 87 has produced a document TR62781 that discusses water treatment for ultrasonic measurement purposes. Within that there is quite a description of degassing (both chemical and physical methods) and I would personally have thought that some form of recirculating reduced pressure degassing method would be best. There may well have to be quite a lot of parallel outlet-inlet points on a tank of that size but if the water was recirculating all the time through the degassing circuit you should slowly but steadly be able to reduce the dissolved gas content. If you can couple this with something to reduce the surface free area (and thereby reduce the regassing rate) it'll work even better. Our tanks are small in comparison but we find that table-tennis balls floating on the top get out of the way of the scanning rigs as they move, but really slow the re-gassing rate

Be aware that many of the chemical methods listed tend to be single gas specific. In contrast a physical method that reduces dissolved oxygen will also work just as well on dissolved CO2 and nitrogen

Feel free to email me if you need more info

1
 
 Reply 
 

Product Spotlight

AMIGO2

TSC Amigo2 - ACFM technology has developed a solid reputation for accurately detecting and sizing
...
surface-breaking cracks through paint and coatings. As the industry demands increased performance in speed, signal quality, and portability, it’s time for an evolution. It’s time for Amigo2.
>

Wireless TOFD scanner

Quick, accurate and highly reproducible welds testing. The System operates wirelessly and is compat
...
ible with any type of Windows based Laptop, Desktop or Tablet.
>

Cygnus 6+ PRO Multi-Mode Ultrasonic Thickness Gauge

The Cygnus 6+ PRO thickness gauge is the most advance gauge within the Cygnus range with key featu
...
res including: comprehensive data logging; A-scan and B-scan display; manual gain control; Bluetooth connectivity; and much more. With its unique dual display and three measuring modes (Multiple-Echo, Echo-Echo and Single-Echo), this surface thickness gauge offers maximum versatility for inspections.
>

FD800 Bench Top Flaw Detectors

The bench-top FD800 flaw detector range combines state-of-the-art flaw detection with advanced mater
...
ial thickness capabilities. Designed for use in the laboratory these gauges are the tool you need for all your flaw detecting needs.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window