In the construction of modern water supply systems, the reliability and durability of pipe connection technology are directly related to the safe operation of the entire water supply network. As an advanced pipe connection method, HDPE (high-density polyethylene) hot melt butt fittings have become the preferred solution in the field of water supply engineering due to their excellent sealing performance, ultra-long service life and convenient construction process. This article will comprehensively analyze the technical characteristics, construction process, quality control and industry application of HDPE hot melt butt fittings for water supply system, and provide professional reference for water supply system design and construction.
Advantages of HDPE hot melt butt fittings for water supply system
1. Excellent physical properties
HDPE hot melt butt fittings have the following significant features:
Density range 0.941-0.965g/cm³, with both high strength and good toughness
Tensile strength ≥22MPa, ring stiffness can reach SN8 or above
Excellent environmental stress cracking resistance (F50≥1000h)
2. Outstanding engineering advantages
Compared with traditional connection methods, HDPE hot melt butt fittings have:
Leak-free connection: Molecular-level fusion forms an overall structure, and the leakage rate is close to zero
Extremely long life: The designed service life is more than 50 years, which is 2-3 times that of galvanized steel pipes
Strong corrosion resistance: Completely resistant to chemical corrosion in water and soil
Excellent hydraulic properties: Smooth inner wall (roughness coefficient is only 0.01), water delivery capacity is 30% higher than steel pipes
Good economic efficiency: The comprehensive cost is lower than that of metal pipes, and the maintenance cost is extremely low
Detailed explanation of hot melt butt welding process technology
1. Standard construction process
Pipe end preparation:
Use a special milling cutter to mill the pipe end to ensure that the end face is flat and vertical
The cutting amount is controlled at 0.2-0.5mm to form a fresh weld surface
Heating stage:
The heating plate temperature is set to 200-220℃
The welding pressure is 0.15-0.3MPa, and the time is adjusted according to the pipe diameter
Switch butt welding:
Quickly remove the heating plate and complete the pipe end butt welding within 5 seconds
The butt welding pressure is slightly higher than the welding pressure (about 0.3-0.4MPa)
Cooling and shaping:
Maintain the butt welding pressure until the cooling temperature is lower than 40℃
The cooling time is calculated as 1min/mm wall thickness
2. Control of key process parameters
| Pipe Diameter (mm) | Heating Time (s) | Changeover Time (s) | Cooling Time (min) |
| 90 | 45-60 | ≤5 | 6-8 |
| 160 | 70-90 | ≤5 | 10-12 |
| 315 | 120-150 | ≤5 | 20-25 |
| 630 | 240-300 | ≤5 | 40-50 |
HDPE hot melt butt fittings for water supply system applications
1. Typical application scenarios
Municipal water supply trunk network:
Diameter DN200-DN1000 trunk pipeline
Water supply system with working pressure of 0.6-1.6MPa
Community secondary water supply:
Ring water supply network inside the building complex
Special pipe fittings for transition connection with stainless steel pipes
Rural drinking water project:
Water supply network in complex terrain areas
Directional drilling construction section crossing rivers and roads
Industrial water supply system:
Circulating cooling water pipeline of power plant
Process water network of chemical enterprises
2. Special application cases
High altitude area: Use HDPE pipe fittings with anti-ultraviolet formula, and the weather resistance is increased by 50%
Seismic zone area: Use flexible connection system, which can withstand 0.5m fault displacement
Low temperature environment: -40℃ special formula pipe fittings, maintain good impact resistance
Quality control and acceptance standards
1. Quality inspection system
Raw material control:
PE100 grade raw material, melt index (MFR) 0.2-0.4g/10min
Passed GB/T 13663.2-2018 standard inspection
Process inspection:
Tensile test of the first piece per day (strength ≥ 90% of the parent material)
Weld flange height inspection (should be 10%-30% of the wall thickness)
Finished product inspection:
100% appearance inspection (no defects such as cold welding and burning)
Ultrasonic inspection at a ratio of 5%
2. Acceptance standards
Pressure test: 1.5 times the working pressure, pressure drop ≤1% for 30min of stable pressure
Sealing test: 0.6MPa air pressure, soap water test without bubbles
Dimensional deviation: outer diameter tolerance ±0.3%, wall thickness tolerance +12%/-0%
HDPE hot-melt butt fittings are reshaping the construction standards of modern water supply systems with their excellent performance and reliability. With the continuous advancement of material science and construction technology, this technology will surely play a more important role in ensuring drinking water safety and improving water supply efficiency. It is recommended that water supply companies give priority to the use of HDPE hot-melt butt welding technology in new construction and renovation projects to obtain the best full life cycle benefits.
