8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 1/6

How Automated Water JettingImproves Tube Bundle

Cleaning Efciency

“The Leader in Water Jet Productivity” 

29830 Beck Road

Wixom, MI 48393-2824

Phone: (248) 624-5555

Fax: (248) 624-0908

e-mail: nlbmktg@nlbusa.com

www.nlbcorp.com

8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 2/6

Introduction

To keep today’s ultra-ecient heat exchangersystems operating at peak eciency,petrochemical and rening acilities must cleantheir tubes thoroughly and regularly to keep themclear o process-related deposits. Such depositscan drastically limit the system’s ability to transer

heat, driving operating costs substantially higher.Add indirect costs like downtime and compliancewith saety and environmental regulations, and thepressure on tight operations budgets is intense.

To meet this challenge, more and more companiestoday are cleaning tubes with high-pressure water

 jetting (20,000 to 40,000 psi, or 1,400 to 2,800 bar).Water jetting has been widely used or productremoval and industrial cleaning or some 40 years.It removes even hardened deposits thoroughly

and cost-eectively, oten saving thousands odollars while signicantly improving productivity.Semi-automated systems, or example, can clean100 tubes 75% aster than manual methods,depending on the size o the tube bundle and thematerial being cleaned out. Fully-automatedsystems can clean them 90% aster than manualmethods.

A high-pressure water jet tube cleaning systemtypically involves a small nozzle placed on the endo either a rigid tube (or straight line cleaning) or a small fexible hose (or tubes with bends).High-pressure water rom a pump unit is ed through the tube or hose and exits the nozzle at aspeed and pressure that removes even the hardest residues, rust and scale. Then the wastematerial is fushed out o the tubes and rinsed away.

Traditional Manual Methods

One o the most common and most economical methods or cleaning tubes is manual water blasting. There are anumber o variations on this, but all generally require anoperator to manually eed the nozzle into each tube that

needs to be cleaned. Once the nozzle is positioned in thetube, the operator starts the fow o high-pressure waterby depressing a oot pedal. This process, while eective,has drawbacks. First, it can be time-consuming. Secondholding on to a hose as high-pressure water rushesthrough can lead to operator atigue over time. Third,the operator may not always eed the nozzle into the tubeat the same speed, which can result in uneven cleaning.

Water jetting is widely used or shellside cleaning as

well as tube lancing.

 Manual water jet tube lancing

8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 3/6

Automated Systems

 Automated systems clean several tubes at once while

the operator stands clear.

Automated systems are a superior method orremoving product build-up rom heat transertubes. Not only do they save many hourscompared to manual methods (see Table 1,page 4), but more importantly they eliminate thevariables an operator brings to the process while

removing him or her rom the immediate vicinityo the high-pressure water.

Automated systems or cleaning tubes typicallyhave multiple lances or hoses, a means o movingthem across the ace o the tube bundle, and asystem or eeding them in and out o the tubeswithout manual labor. The operator typicallycontrols the actions o the system rom a remoteposition nearby. Hoses and lances are usuallyprovided in dierent sizes to suit a variety o tube

diameters; changeover should be simple to minimize downtime.

Types o Automated Systems

There are two basic types o automated tube lancing systems: those that use fexible hoses andthose that use rigid tubing. Each has advantages and disadvantages, and choosing the rightsystem can go a long way to assuring a user o the most ecient, productive tube cleaningpossible.

Flexible Lance Systems

 Dual fex lance system with manual eed

Automated systems with fexible hoses have twomajor advantages: the fexible lances can goaround bends in the tubes and oer morepositioning fexibility during the cleaning process.The larger o these types o systems will otenhave an X-Y positioning device that lets theoperator put the hoses into position or thecleaning cycle. These systems oten eed asmany as three individual hoses into the tubes atthe same time. Smaller fexible hose systemstypically have only one or two hoses, with a

hand-held device so the operator can manuallymove them rom tube to tube.

When fexible hoses are used, hose managementmust be considered. Older systems generally

used a hose reel to roll up the hoses and move them orward or backward as the lances were edin and out o the tubes. While this kept the hoses under control, the material being cleaned out othe tubes oten ound its way back into the reel, ultimately causing the system to bind up. Thismade the reel one o the most problematic portions o the system.

8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 4/6

Triple fex lance system with mechanical eed

The newest generation o automated fexibletube cleaning systems has solved this problemwith a track drive system that captures eachhose and drives the back-and-orth motionrequired or cleaning. The hoses are allowed to

 eed out behind the device and simply lie on thefoor. The elimination o hose reels greatlyreduces the amount o space required or a

fexible lance system, especially compared to arigid lance system.

Rigid Lance Systems

Quintuple rigid lance system with climate-controlled

operator station

Rigid lance systems are not as fexible asautomated systems, but make up or it in sheerperormance. These systems have small-diametepipes with high-pressure nozzles on the ends toclean tubes. Since the piping is rigid, the systemcan literally orce the nozzles through theobstructed tubes, adding mechanical orce to thecleaning action o the water jets. However, thepiping tends to be quite long (30 eet is notuncommon), so a rigid lance system can requireup to 6 times more operating space than a fexible

lance system.

Fully automated systems can clean more tubes ata time, providing the highest level o productivity.They also provide the most protection andcomort or the operator. The system shown herehas an operator station above the tube bundlewith ull controls. It gives the operator a ull viewo the cleaning process, a comortable seat and a

climate-controlled environment.From here he can control the in-and-outmovement o the lances and the up/downmovement o the levelers. I the system has abundle roller option, he can also rotate the tubebundle as needed.

8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 5/6

Productivity

As the examples in Table 1 demonstrate, semi-automated and ully automated water jettingsystems require about hal as much time per pass as manual water jetting, and this advantageincreases as lances are added. A ully-automated 5-lance system can clean 100 tubes in a littleover an hour, compared to 16 hours with labor-intensive manual cleaning. Actual cleaning timescan vary greatly, depending on the length o the tubes and the type o material being removed.

Table 1

Tube Cleaning MethodNumber of

Lances

Number of

Tubes to Clean

Time per

Cleaning Pass

Total Cleaning

TimeTime Saved

Manual Water Blasting 1 100 10 Min 16 Hours NA

Semi-Automated Dual Flex

Lance System2 100 5 Min* 4 Hours 12 Hours

Semi-Automated Triple Flex

Lance System3 100 5 Min* 2.75 Hours 13.25 Hours

Automated Quintuple Rigid

Lance System5 100 4 Min* 1.3 Hours 14.7 Hours

* Automated systems allow the operator to clean on both the in and out stroke o the cleaning lance.

In addition to increasing productivity, automated water jet systems can improve the quality andconsistency o the cleaning process. The systems discussed in this white paper allow tubes to becleaned both on the inward and outward passes, so more material is removed in less time. Theyalso allow the operator to set the eed rate so that each tube will be cleaned in an even,repeatable manner.

Saety and Ergonomics

Automated tube cleaning systems have benets or operating personnel as well. Manual hose orlance eeding can be tiring over time (aspreviously noted) and can expose operators tobacksplash and debris. With a semi-automatedsystem, the operator has complete controlwithout coming near the waterblasting, using aremote (even wireless) control.

8/6/2019 Automated Water Jetting for Tube Bundle

http://slidepdf.com/reader/full/automated-water-jetting-for-tube-bundle 6/6

“The Leader in Water Jet Productivity” 

Conclusion

Tube bundle cleaning plays a key role in maintaining heat exchanger eciency, which is a critical actor in petrochemical quality and productivity. High-pressure water jetting is a proven method or keeping tubes clear o deposits, and today’s automated systems are more eective — andmore operator-riendly — than ever beore. They can reduce cleaning time by 75% to 90% vs.manual water jetting, and processors can choose rom dierent levels o automation to suit theirspecic needs.