Focal Points: Sponsored links

New CMMS! MVP Plant - Smart Software for Smart Maintenance

 Join The Association For Maintenance Professionals

RCM-EAM-MTrain-2009 Daytona Beach 

Infrared windows and safety products

Follow us on Twitter



 


Resources for Maintenance & Reliability Professionals

Navigation
Home
News
Newsletter
Knowledge Bases
Web Workshops

Tutorials
Directory
Books
Maintenance-Tips
Conferences
Forums
Photo Albums
Reliability Radio
Benchmark
Calendar

Gadgets
Jobs

Twitter
Network Links
Archives

en Español
XML/RSS Feeds Advertise

Click to verify BBB accreditation and to see a BBB report.

Our privacy promise: We respect your privacy and never sell or rent our subscriber lists, a fact that is certified and audited by BBBOnline.com.  Subscribing will not result in more spam! I guarantee it!  

Reliabilityweb.com announces the Top 100 list each year as a way of delivering value to our members and as a way of acknowledging the extra work that these companies put into creating a web site that contributes to the overall maintenance and reliability community.

 

 

Ultrasound Detection - Testing Tube and Shell Condensers
by Chuck Petersen,
Petersen Predictive Maintenance 

In order to Test these condensers with Ultrasound we must first understand how they work. These condensers come in all sizes and shapes. But usually the principle is the same. The product is run through the shell side and the water is run through the tube side. Thus the water flowing through the tubes carries the heat away allowing the boiling product to condense back into a liquid, or in some cases just cool down to a desired temperature.

In this picture the water enters the condenser through the large pipe on the end. (Green Circle) It then travels through the tubes and out the other end. This condenser was approximately 40 feet long.

The product enters the condenser through the pipe that we see in the center of the picture. (Yellow Circle) Between these two entry points there is a thick plate that is called a tube sheet.

The water and the product never actually contact each other but the heat is drawn away by the flow of water through the tubes that are running through the product.

This large plate over the end of the condenser is called the head plate. There is one on each end. We will need to pull these head plates so we can get to the tube sheet. That is where we will find any leak that there might be in this condenser.

Here we see a crew pulling the head off of one end of the condenser. These heads are very heavy and should be moved with a crane or some other device designed for lifting.

The tube sheet is the barrier between the water and the product. It is positioned between the product and water entry and exit points on each end of the condenser. It also holds the ends of all the tubes.

After the head has been removed and the water box has been tested for safe entry (Confined Space) then we will proceed to enter for testing. This is the tube sheet. Here we can see the ends of the tubes that run the full length of this condenser. This is also called the water box. The water comes in here and runs through the tubes and out the other end taking the heat with it. If one of these tubes springs a leak then the product because of the higher pressure is leaked into the water. In this case it was propane, so the vapor cloud above the cooling tower was not all steam; it was partially leaking propane being carried to the tower by the water.

This is where we check for leaks. These tubes are about ½ inch in diameter. There are approximately 2200 of them. To test each one individually from both ends would take for ever. In this case we leave the shell side charged or we de-pressure it and then re-pressure it with Nitrogen. That way with the shell side at a higher pressure we can here the leaking tube. These higher pressure usually only needs to be approximately 25 to 30 psi.

After the water box has been cleared by operations and all safety measures are in place we actually get into the water box and listen for the leak with the UE SYSTEMS ULTRAPROBE 10000.

Once inside the water box and using the gross to fine method we can determine where the leak is. At 25 to 30 psi differential it is very easy to find these leaks. After we have located the general area of the leak then I take a cheap plastic funnel and place end of the funnel inside the tube. I then use the rubber focusing module check inside the funnel and hear the leak. I then check outside and all around the funnel. If I hear no leaks outside and knowing that Ultrasound will not penetrate a solid this indicates to me that I have located the exact tube that is leaking.

This tube is usually plugged and then we go to the other end and plug the other end as well. This takes that tube completely out of operation and the unit can be reassemble and put back on line. I have found condensers with one tube leaking and I have found them with several tubes that leak, be sure to check them all closely.

This entire operation took approximately 4 hours from start to finish.

Find Ultrasonic Vendors here
 

Discuss this article at MaintenanceForums.com

Search provided by
 MRO-Zone.com and Google


 

 
 
 
List Your Web Site Editorial Policy Privacy Policy Contact us
Feedback © Copyright 2000-2008 NetexpressUSA Inc. All rights reserved Terms of Service Trademark Notice