Step by step procedure for fixing of Thermoplastic-PPG

01. Select the area where Thermoplastic-PPG lining has to be done.
02. Check the following in selected area.
· Check dryness of surface
· Roughness of Surface (For PPG surface requirement is sand finish & it should not be too smooth (polished surface))
· Check loose particles if any
03. Cut the Thermoplastic PPG sheet that can be fixed in selected area from the roll (Size of roll is 10 Meter * 1.5 /1.35Meter).
04. Clean the surface where the PPG lining has to be done So that no loose particles remain there.
05. Mark location of area where PPG lining has to be done.
06. Mix Chemical A to Chemical B thoroughly to form Chemical AB in proportion of 100: 03
07. Now mix hardener in Chemical AB in proportion of 103: 02 (Hardner is fast setting compound where the mix chemical will set within period of 1-2 hours, but its gel time starting is 25- 30 minutes) & apply mixed coat on the marked surface
08. After that lay the layer of Fiber Mat & applies Mix chemical on it till the fiber mat is thoroughly wet.
09. Now apply mixed chemical on reverse side of PPG sheet where fiber cloth is embossed.
10. Place the PPG on marked surface & apply dead load on it. (Dead load should be applied in such a way that PPG should be in full contact with base surface).
11. Allow PPG sheet to cure Curing time of Mix chemical is 2-3 hours. Curing time has to be selected according to the size of the sheet and surface area. It can be adjusted by the qty of the chemicals added.
12. Once the above process is completed check the adhesive at intermediates interval for curing.
13. After confirmation remove the dead loads.
14. Now once the PPG sheet has been fixed clean the edges of sheet where any chemicals are there so that proper welding can be taken up and fine M.S. wire will be kept.
15. Joints of Thermoplastic-PPG are welded by Fusion welding through Hot air gun.
16. When the welding is complete check the entire area with Spark testing Machine for any leakages from the joints.

Welding Procedure

Both sheets should be scraped gently to ensure proper welding.

Thermoplastic sheets will be welded using the fusion welding technique. In fusion welding technique set the temperature (350Oc) setting of your inbuilt compressor plastic blower so that the welding rod (3-5 MM Dia) should melt cleanly and should not be discolored.

Lay the tip of plastic blower on welding rod & on the surface of the sheet simultaneously and slowly melt the rod on the joints by pulling towards you in such a way that welding rod should be clearly welded & have fusion with the surface.

Spark Testing Procedure

High frequency spark tester consists of a solenoid and an interrupter, which has a natural high frequency, and when the current passes through the solenoid the hammer is attracted by its core, thereby breaking the circuit and at the same time charging the condenser. The hammer then springs back reforming the contact and allowing the condenser to discharge through an inductance of a few tons of thick wire of the tesla coil contained in the handle. This discharge beam oscillatory in nature induces a very high potential in the inner winding of this tesla coil. The intense electrostatic field produced within this inner coil give a diffused brush discharge from a small metal rod inserted in the handle of the tesla coil. This metal rod when brought with in one cm of the lining of the tank etc. produced a diffused spray discharge but if there is any minute crack or microscopic hole in the lining whether it be glass, rubber, or any other insulation this diffused discharge is concentrated into a bright spark passing through the hole or crack.

This phenomenon is attributed to the fact that high frequency currents possess a very high tendency of taking the nearest passes to earth. This method is therefore very useful in detecting faulty welding.

In testing the tip of the metal rod from the handle of spark tester is run along the welded joints and if porosity is present blue spark will readily appear, the voltage rating of tester may vary from 5000 to 30000 volts depending upon the thickness of lining and magnitude of the porosity detected is 10000 to 15000 volts is a good general practice.

Guide lines for Machine Setting.

Machine parameters should be set as given below.

This is a general guideline, machine has to be set and the qualified engineer deputed by the CRESCENT as per the site conditions should frizz its parameters.

Once it will be decided, technicians or any one else is not authorized to disturb it without the permission of the concern site engineer. The same setting should be continuing till the completion of the testing.

Visual Inspection

• All the surface where PPG Lining to be applied should be free from all dust, dirt and grease etc.
• PPG Sheet which is to be fixed should be cleared of all the foreign material.
  

Lining welding inspection

• No dust, sand or foreign particle is allowed at joints. And homogeneity should be properly ensured at joints.

Bond Test

• Proper bonding should be ensured be doing sound test using mallet hammer.

Spark Test

• All the welding joints should be tested, if possible in the presence of representative of Client.
• Test certificate of all the material should be submitted to SMU.

Testing of the PPG Flooring and Lining.

Test Report for Welding Joints

Not a signal pinhole is permissible for welding joints test.

Test Report for Bonding of Sheet