Puzzled Over Welded-Bloc Maintenance & Cleaning?

Puzzled Over Welded-Bloc Maintenance & Cleaning?

The utilization of welded-bloc heat exchangers in your facility has many advantages.

Welded-Bloc Heat Exchangers

  • are compact, space-saving units.
  • allows for optimum heat transfer in half the space with no internal gaskets.
  • allows you to cool or heat the most tenacious of media at temperatures, pressures and flows unattainable by other types of exchangers.
  • are used for a wide variety of applications, condensers, re-boilers, economizers, evaporators and many others

However, like any other heat exchanger, welded-bloc exchangers need to be on a routine cleaning and maintenance plan. Given the fact these units are used for extreme conditions, the fouling can be a baked-on, compacted nightmare. When left unattended, the excessive fouling buildup in the unit will result in operations that run these units beyond designed pressures.

Results: Plate cracking, baffle damage, fatigued weld joints, pitting and corrosion.

First Challenge:

Tear-down, cleaning, repairing, testing and reassembly.
Conventional high-pressure water blasting is not a viable option.
Chemical Cleaning is only 65% effective – minimal heat transfer gains.


Second Challenge:

Returning the unit to 100% reliability is a must.
Hidden failures cannot be overlooked.
Cleanliness will determine the degree of reliability of any repairs and the degree of heat transfer obtained.


National Heat Exchange (NHE) offers over two decades of experience in routine maintenance, cleaning, repairs and rebuilds of all types of exchangers. NHE first looks at each customer’s unique circumstance and then develops a tailored scope of work and proposal to meet their needs. Reliability starts with cleaning, and with National Heat Exchange’s patented Enclosed Mobile Bundle Cleaner (EMBC) — coupled with its custom-blended chemistry — unprecedented levels of cleaning are accomplished. The welded-blocs are disassembled, exposing the core (heart). The unit is then cleaned from every angle using a low-pressure/high-flow of 1,500 gallons per minute of a properly matched chemistry that is continually filtered in the EMBC’s closed-loop system. The EMBC system allows NHE to both monitor cleanliness and reuse the cleaning solution, giving customers a level of clean not attainable via any other method available while at the same time not sacrificing the environment.

Once the unit is cleaned to the parent metal, NHE runs the unit through several testing procedures. Even the smallest hairline crack or pinhole leak must be found, as these can open up and cause catastrophic failure during operation. After the leaks are identified and the weld repairs are made, NHE will retest the unit while it is disassembled to be sure there are no visual cracks or pinholes. The exchanger is then reassembled and hydro-tested to factory specification.

National Heat Exchange has taken the time and money to build relationships with its suppliers, train its technicians, and invest in the R&D necessary to complete welded-bloc cleaning and repair projects in the toughest of circumstances. This allows NHE to get your exchanger back to you done right, reliably and in an efficient timeframe. NHE also works closely with OEMs to provide replacement blocs as well as engineering for new applications.

For more information, visit nationalheatexchange.com,

1-330-482-0893     or   info@nationalheatexchange.com.