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WELDING & JOINING
HOT AIR/GAS WELDING
SOLVENT JOINTING
SOCKET FUSING JOINTING
BUTT FUSION JOINTING
We undertake project for erection and commissioning for our products. We are a team of experienced and qualified Engineers. We have more than fifteen years of experience, which help understand customer requirements as well as adoption of modern traits. We are equipped with all types of latest tools as well as skilled manpower. To ensure best quality we have In-House Quality Control Department, which follows the strict norms of the respective standards for different products or as per customers’ specifications. We also offer third party inspection for our manufactured products. Your satisfaction is our Motto.
WELDING & JOINING:
Sangir Plastics uses various sophisticated methods to join plastic at fabrication shop and site. The thermoplastics can be joined either by welding, fusion or cementing while thermosetting/FRP can be joined by lamination.
Methods MATERIALS
  PP PVC CPVC PVDF HDPE
Hot air welding R R R R R
Solvent cementing NR R R NR NR
Socket/Butt fusion R NR NR R R
NOTE: R: Methods Recommended; NR: Methods NOT recommended.
Since the type and caliber of tools used for jointing in various methods are as important for high output, as maintaining excellent quality SANGIR PLASTIC has done in-depth study over a period of time in developing new sophisticated and automated tools.
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HOT AIR/GAS WELDING:
With hot gas welding the edge areas and the outer zones of the filler materials are transformed into plastic conditions as a rule means of heated air and joined under pressure. The gas is being made free of water, dust and oil by fixing filters.
The filler or welding rods are available from 2 to 6 mm dia. Two types of welding nozzles can be employed viz fixed nozzle for rods of fixed length & running nozzle for continuous long bundle of rod. Temperature required for different material is controlled by thermostat. Air required will be supplied through compressor.
Material Welding force (N) with welding rod of dia. Hot air temp. oC Air quantity V/Min.
  3mm 4mm
PP 10 to 16 25 to 35 280-330 40-60
HDPE 10 to 16 25 to 35 300-350 40-60
PVC 15 to 20 30 to 45 220-300 50-75
CPVC 20 to 30 30 to 45 310-350 60-70
All the welders enganged in work are periodically tested for weld strength test. Also all welders are approved for the same test based on the test carried out at IIT, Mumbai.
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SOLVENT JOINTING:
This method is employed only for jointing pipe with socket type fitting i.e. where pipe will be inserted into the fitting socket. Pipes & socket type fittings are cleaned, debured and chamfered to make it ready for cementing. Primer to be coated by using brush on the areas to be joined i.e. outside of pipe and inside of fitting till surface becomes tacky. Solvent cement is applied on the tacky surface for bonding. Then pipe will be inserted in fitting and both pieces will be held under pressure till it gets bonded firmly. At 25oC the handling time for cement is about 4 times and completed joint to be held at approx. 10 minutes at 25 – 30oC.
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SOCKET FUSING JOINTING:
This method is used for jointing pipe with socket type fitting only. Molded socket type fittings are available up to 160m, diameter, so this method is used for jointing pipes and fittings upto 160mm diameter. Length of pipe which has to be inserted in fitting socket for fusion to be peeled off in order to remove the glossiness on pipe surface and to make it rough. For heating the parts, firings to be inserted on heating spigot while pipe to be inserted in heating bush. Values of time for heating, change over time, jointing time cooling time and pressure required etc. would be same as indicated for butt fusion. Sangir PLASTICS uses fully automated machine to do the fusion, cutting, peeling, chamfering and deburring operations.
D T, Thickness in mm d1 l Heating time in sec.
20 2.5 19.85-19.95 14 5
25 2.7 24.85.24.95 16 5
32 3.0 31.85-31.95 18 7
40 3.7 39.75-39.95 20 8
50 4.6 49.75-49.95 23 12
63 3.6 62.65-62.95 27 18
75 4.3 74.65-74.95 31 24
90 5.1 84.65-84.95 35 30
110 6.3 109.55-109.95 41 50
Typical Sketch Showing Socket Fusion Technique.
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BUTT FUSION JOINTING:
Fusion areas of pipes & fittings are heated to fusion temp and jointed by means of mechanical pressure without using filler rods. This is carried out on butt fusion machine to maintain constant pressure, uniform gap width and perpendicularity. This machine is similar to socket fusion machine, only the heating elements will be changed.
Values Of Butt Fusion Jointing Process.
Pipe wallthickness, mm Heating
element
temp., oC
Equalization
at P=0.1N
/mm2 Height of bead, mm
Heating time at P=0.01N/mm2 for various materials, sec. Change over time, sec. Time to reach full jointing pressure, sec Cooling time under jointing pressure P=0.15N
/mm2, sec.
2-3.7 215 0.5 - 30-40 40-70 4 3-6 4-5
4.3-6.9 210 0.5 65-115 40-70 70-90 5 5-8 6-10
7.1-11.4 205 1.0 115-180 70-120 90-120 6 8-10 10-20
12.2-18.2 200 1.0 180-290 120-170 120-150 8 10-15 20-30
20.1-25.5 195 1.5 290-330 170-210 - 10 15-20 25-28
BUTT FUSION JOINTING – ANGULAR (BEND FABRICATION)

The machine is used to cut the pipe in any required angle by cutter on machine. Then these cut pieces or segments of pipe will be butt jointed in angular direction to form a bend. All values of butt fusion will be maintained as stated earlier.

Schematic Diagram Of Socket/Butt Fusion Machine.

Chamfering, cutting to size, heating, pressurizing etc. operations done on the machine. Machine is mounted on moving trolley.

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