Jointing technology
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Jointing technology

Date:2015-01-11

a)       solvent cement jointing

1. CUTTING

     The pipe can be cut with ordinary facilities like rolled plastic cutter, electric cutter or plastic using hacksaw with good tooth outline. The pipe should be cut vertically and smoothly when cutting with hacksaw, since the connecting area will be larger if the pipe is cut much vertically.

2. DEBURRING

Angels removing tools or grater will be used for removing burrs inside and outside the pips and clearing filings. Appropriate bevel (like drawing on the right) is recommended so that the pipe orifice can insert into fittings easily and reduce the chance of solvent adhering onto fittings.

 

3. FITTINGS PREPARE

     Removing the bust and moisture upon pipes and connection of fittings with clean dry cloth and checking the connecting situation between fittings. The test inserting depth of pipes should be 1/3 ~ 3/4 of the fitting socket.

 

4. DETERGENT PAINTING

     The connected areas between pipes and fittings should be penetrated and soften with detergent in order to enhance the taking effect around solvents. The detergent will be painted evenly upon pipes faucet and surface of fitting faucet areas with half of pipe diameter painting tools or brushes (wasted cloth is not recommended). As to long size pipes, more times’ painting and usage of detergent is required if necessary so as to make sure the soften performance of pipes’ surface.

 

5. SOLVENT DETERGENT PAINTING

     The solvent detergent should be painted on the surface of pipe after it is painted with detergent and the connecting area should be penetrated and soften. The viscose should be put on the nature brush of which the diameter is half of the pipe and the outer surface for the end of pipe should be also covered with viscose. Appropriate viscose needs to paint inside the connecting area of fittings. If the size of pipe is larger than 2 inch, two layers of viscose or more times of painting are required to paint at the end of it.

 

6. COMBINATION

After painting, the pipe should be inserted into the fitting at once and rotated for 1/4 circles. And the pipe must reach the end of the fitting. The combination shall be maintained for 10s to 15s for consolidating to make sure the elementary connection (two persons are required to tightly hold the connection area for about 1-3 min if the pipe is more than 6 inch). And the phenomena of viscose leaking around the connection point of pipes and fittings shall be obvious. If not, it means the painting of viscose is not adequate, as a result, the fitting should be scraped and recombined. For the overflowing viscose, it can be wiped with tatters.

 

7. THE AMOUNT OF GLUING PER QT VOLUME.

b)       Fusion jointing of PPH

1. Fix heating bushes

Attach the heating bushes on the heating tool, maximum two set of bushes can be attached in the same time.

2. Check the temperature

Once the socket fusion machine is on, set the temperature on the electronic display. Which must range between 255oC and 265oC. To ensure correct temperature, frequent calibration is recommended.

3. Clean the heating tools

After checking the temperature, wipe th heater bush with a clean cloth, this operation must be repeated after each welding.

4. Cut the pipe

Cut the pipe at right angle, if necessary remove burrs from inside, if necessary, cut deformed or damaged pipe ends.

5. Clean pipe & fitting

Clean the fitting inside and the pipe outside (the presence of dust, grease or other impurities can affect the fusion quality and lead to leakages)

6. Mark the pipe

Mark the insertion depth on the pipe for (see table), the mark must remain visible under heating and joining.

 

Summary Value table

pipe diameter

(mm)

minimum wall thickness

(mm)

Insertion depth

(mm)

heating time

(sec.)

Jointing time

(sec.)

cooling time

(min.)

20

3.4

14

6

4

2

25

4.2

16

7

4

3

32

5.4

18

8

6

4

40

6.7

20

12

6

4

50

8.4

23

18

6

5

63

10.5

26

25

8

6

75

12.5

28

30

8

8

90

15.0

31

40

10

8

110

18.4

33

50

10

8

125

20.8

40

60

10

8

 

 

7. Heat pipe & fitting

Push the pipe and the fitting straight into the heating bushes, pull out pipe and fitting slowly and without twisting once the heating time has elapsed.

8.Joint pipe & fitting

Push the pipe into the fitting so that the welding bead of pipe and fitting touch together, during the jointing time, small adjustment in angle and alignment can be made, during the cooling time, any stress on the joint must be avoided.

9. Fusion inspection

The outer fusion bead must be inspected, a double bead must be uninterrupted all around the pipe circumference.