The document contains frequently asked questions and answers about CTI Shield/Seal tube repair technology. Traditionally, heat exchangers are fully retubed once 10% of tubes are plugged, but CTI Shield can protect damaged tube sections at lower cost and faster than full retubing. Shields are customized and take 7-8 weeks for manufacturing but only 10-12 hours to install 700-1000 shields. Shields are made from more noble metals and can last at least twice as long as the original tubes. CTI Shield provides a reliable, long-term repair technique that extends equipment life by 10 years or more at lower cost than full retubing.

1. FREQUENTLY ASKED QUESTIONS
Q WHAT HAS BEEN THE PRACTIE ALL OVER THE WORLD?
A CONDENSER & HEAT EXCHANGERS ARE DESIGNED WITH
ALLOWANCE OF PLUGGING 10% TUBES. ONCE 10% PLUGGED THEN
RE-TUBE 100% IGNORING THE FACT THAT 90% TUBES ARE STILL
OPERATIONAL – OLD PRACTICE.
Q WHAT IS THE BENEFIT OF CTI SHIELD / SEAL?
A TUBE FAILURE COMMON IN NATURE AND NORMALLY IT IS LOCATED
WITH IN FEW INCHES AT THE TUBE INLET END. CTI SHIELD CAN BE
USED TO PROTECT THE DAMAGING LENGTH OF TUBE TO PROTECT
IS FROM DAMAGE OR RESTORE THE DAMAGED TUBE AT LESS
COST AND WITH IN LESS TIME.
Q HOW LONG IT TAKES TO INSTALL CTI SHIELD / SEAL?
A NORMALLY IT TAKES 10 TO 12 HOURS TO INSTALL 700 TO 1000
SHIELDS.
Q ARE THOSE SHIELDS READILY AVAILABLE?
A THEY ARE CUSTOMIZED. THEREFORE IN MOST CASES THEY NEED
TO BE MANUFACTURED WHICH REQUIRE 7 TO 8 WEEKS.
Q HOW LONG SHIELD IS GONNA LAST?
A CTI SHIELD IS ALWAYS MADE FROM MORE NOBEL METAL YET

2. MAINTAIN GALVANIC COMPATABILITY. ASSUMING 1
ST
TUBE LEAK
APPEARED FIVE YEARS AFTER IN OPERATION AND IF YOU RE-TUBE
WITH SAME TUBE MATERIAL, IT WILL AGAIN FAIL IN SIMILAR TIME
FRAME. CTI SHIELD WILL AT LEAST LAST FOR THAT TIME FRAME.
PRACTICALLY, IT STAYS AT LEAST TWICE THE TUBE FAILURE TIME.
BECAUSE A STRONGER MATERIAL SHOULD WITH STAND ON THOSE
OPERATING PARAMETER ALMOST FOR EVER IF FAILURE
MECHANISM IS IDENTIFED CORRECTLY.
Q CAN WE CALL THIS IT A PERMANENT SOLUTION?
A IT IS RELIABLE LONG TERM REPAIR / RESTORATION TECHNIQUE TO
PROTECT THE FAST WEARING LENGTH OF TUBE. NO DOUBT, YOU
GOT TO RE-TUBE ONE DAY. IT IS JUST LIFE EXTENSION PROGRAM.
IF YOU WERE TO RE-TUBE IN TEN YEARS TIME, YOU MAY USE THE
SAME TUBES FOR ANOTHER TEN YEARS OR MORE.
Q TUBES ARE NOT LEAKING BUT TUBE TO TUBE-SHEET JOINT. WHY
AND CAN THIS ALSO BE REPAIRED?
A NORMALLY, LEAKS APPREAR FROM TUBE TO TUBE-SHEET JOINTS
SINCE EROSION CAUSE JOINT LOOSENING. CTI SHIELD IS
INSTALLED TO RESTORE THE TUBE TO TUBE-SHEET JOINT AND
ALSO PROTECT THE DAMAGING LENGTH OF TUBE SINCE EACH
END OF SHIELD IS EXPANDED.
Q HOW CAN YOU ENSURE SEAL IN THE TUBE SINCE THERE IS NO
TUBE-SHEET BUT ONLY TUBE WHICH IS DAMAGING ALREADY?
A ANY ONE CAN EXPAND AT TUBE SHEET. IT IS ENSURED BASED ON

3. VAST EXPERIENCE AND KNOWLEDGE OF CTI SHIELD SEALING
ABILITY AND THE SKILL BASED ON CALCULATED EXPANSION TO
GAIN SEAL AT DEEP END WITHOUT DEFORMING THE TUBE. MORE
OVER, LENGTH OF SHIELD IS BASED ON DAMAGING LENGTH TO
PASS THE DAMAGING LENGTH AND EXPAND AT RELATIVLY
HEALTHEIR TUBE AREA.
Q CAN SHIELD BE INSTALLED IN U-TUBES?
A SHIELD CAN BE INSTALLED IN STRAIGHT PORTION OF TUBE. IF U-
BUNDLE IS FAILING AT STRAIGHT END WHICH IS MOST LIKELY. BUT
THE U-BEND IT SELF CANNOT BE REINFORCED BY CTI SHIELD.
Q WHAT IS THE COST COMPARISON?
A CTI SHIELD /SEAL CAN SAVE YOU MONEY AND TIME. NORMALLY
SHIELD CAN SAVE UPTO 50% OF THE COST OF RE-TUBING.
Q WHAT IS THE MATERIAL OF CTI SHIELD / SEAL?
A SHIELDS ARE ALWAYS MADE FROM DIFFERENT ALLOYS
DEPENDING UPON THE EXISTING TUBE MATERIAL AND SWEARITY
OF DAMAGE.
Q WHAT IS THE LENGTH OF CTI SHIELD / SEAL?
A SHIELDS CAN BE PROVIDED IN ANY LENGTH DEPENDING UPON THE
LENGTH ON DAMAGE. SO FAR, WE HAVE INSTALLED EIGHT (08)
FEET LONG SLEEVES.

4. Q WHAT IS THE AMOUNT OF IMPACT DUE TO FLOW AREA
REDUCTION?
A SINCE IT IS HEAT EXCHANGING EQUIPMENT, IT IS BETTER TO
EXPLAIN THE OVER ALL IMPACT IN TERMS OF HEAT TRANSFER
LOSS. IF WE INSTALL THIN WALL SHILEDS IN ALL TUBES, IT WILL
NOT BE SIGNIFICANT. FOR YOUR UNSERSTANDING, IT WILL NOT BE
MORE THAN COUPLE OF TUBES PLUGGED.
Q WHAT IS THE THICKNESS OF CTI SHILED / SEAL?
A NORMALLY THE THICKNESS OF CTI SHIELD IS AROUND 0.5mm
(0.020”).
Q WHAT ABOUT THOSE TUBES SUFFER FROM CORROSION ATTACK
TO THE ENTIRE TUBE LENGTH?
A CTI OFFER FULL LENGTH TUBE LINERS. LINERS ARE MADE TO
UPGRADE THE MATULLURGY TO IMPROVE EROSION / CORROSION
RESISTENCE. WE TRANSFORM EXISTING TUBE INTO BIMETALIC
TUBE ON SITE.
Q WHAT IS THE THICKNESS OF FULL LENGTH LINER?
A CTI LINERS ARE SIMILAR IN THICKNESS AND MATERIAL WITH CTI
SHIELD / SEAL.
Q HOW FAST CAN IT BE INSTALLED?
A NORMALLY 200 TO 400 HUNDRED LINERS CAN BE INSTALLED IN
JUST 12 HOURS.

5. Q HOW MUCH HEAT TRANSFER LOSS WILL CAUSE THIS?
A 10 TO 12% HEAT TRANSFER LOSS IS DEFINATE. IF THIS IS
ACCEPTABLE FOR THAT PARTICULAR UNIT, THEN IT IS DEFINITELY
AN ECONOMICAL SOLUTION TO UPGRADE THE MATERIAL IN LEAST
TIME.
Q CAN SHIELDS OR LINERS BE INSTALLED IN SEAL WELDED TUBES?
A YES BOTH SHIELDS AND LINERS CAN BE INSTALLED IN THOSE
TUBES WHICH ARE ROLLED & WELDED. BOTH SHIELD & LINERS
ARE EXPANDED BEHIND THE SEAL WELD AT THE TUBE ROLLING
AREA.
Q WHAT ABOUT ONLY SEAL WELDED TUBES?
A SORRY, SHIELD OR LINERS CANNOT BE INSTALLED SINCE WE
NEED TO GAIN JOINT SEAL BY ROLLING AT TUBE SHEET.
Q CAN WE USE SHIELDS OR LINERS IN BOILER TUBES?
A NO, BOTH SHIELDS OR LINERS CANNOT BE USED IN THOSE TUBES
WHERE THERMAL SHOCK IS EXTENSIVE.

6. Q HOW MUCH HEAT TRANSFER LOSS WILL CAUSE THIS?
A 10 TO 12% HEAT TRANSFER LOSS IS DEFINATE. IF THIS IS
ACCEPTABLE FOR THAT PARTICULAR UNIT, THEN IT IS DEFINITELY
AN ECONOMICAL SOLUTION TO UPGRADE THE MATERIAL IN LEAST
TIME.
Q CAN SHIELDS OR LINERS BE INSTALLED IN SEAL WELDED TUBES?
A YES BOTH SHIELDS AND LINERS CAN BE INSTALLED IN THOSE
TUBES WHICH ARE ROLLED & WELDED. BOTH SHIELD & LINERS
ARE EXPANDED BEHIND THE SEAL WELD AT THE TUBE ROLLING
AREA.
Q WHAT ABOUT ONLY SEAL WELDED TUBES?
A SORRY, SHIELD OR LINERS CANNOT BE INSTALLED SINCE WE
NEED TO GAIN JOINT SEAL BY ROLLING AT TUBE SHEET.
Q CAN WE USE SHIELDS OR LINERS IN BOILER TUBES?
A NO, BOTH SHIELDS OR LINERS CANNOT BE USED IN THOSE TUBES
WHERE THERMAL SHOCK IS EXTENSIVE.