PE Pipe Butt Fusion Drainage Fittings Expansion Socket
Expansion Socket
Main Functions
Compensation for Thermal Expansion and Contraction of Pipes
HDPE pipes have a relatively high coefficient of thermal expansion (approximately 0.15–0.20 mm/m·°C). Temperature changes (such as high summer temperatures, low winter temperatures, or hot water drainage) cause axial elongation or contraction of the pipes. The expansion joint absorbs these deformations through its internal sliding, bellows, or piston-type structure (typically offering a compensation range of ±50–100 mm or more, depending on the specification). This prevents thermal stress from causing:
Cracking or leakage at joints;
Bending or deformation of the pipe wall;
Damage to fixed supports/brackets;
Overall system displacement leading to siphon failure.
Maintaining the Integrity of Negative Pressure Sealing in the Siphonic System
Siphonic drainage relies on full-bore negative pressure flow (negative pressure can reach -0.05 to -0.08 MPa). Any minor leakage or air ingress will disrupt the siphonic effect, resulting in reduced drainage efficiency or complete system failure. The expansion joint uses a dual-seal design (O-ring + sliding seal or bellows seal) to maintain airtightness during expansion and contraction, ensuring:
No air is introduced (preventing siphon interruption);
No gap leakage occurs (which is more pronounced under negative pressure);
Long-term stable operation of the system (HDPE service life of 50+ years).
Absorption of Pipe Vibration and Minor Displacement
Water hammer, air-water impact, or equipment vibration during drainage is transmitted to the pipes;
The expansion joint buffers these vibrations, reducing stress concentration on heat fusion/electrofusion joints;
It also accommodates minor building settlement or micro-movements from earthquakes (some designs provide limited angular or lateral compensation capability).
Facilitating Installation and Maintenance
Expansion joints are typically installed above the fixed support on vertical stacks or after horizontal
Compensation for Thermal Expansion and Contraction of Pipes
HDPE pipes have a relatively high coefficient of thermal expansion (approximately 0.15–0.20 mm/m·°C). Temperature changes (such as high summer temperatures, low winter temperatures, or hot water drainage) cause axial elongation or contraction of the pipes. The expansion joint absorbs these deformations through its internal sliding, bellows, or piston-type structure (typically offering a compensation range of ±50–100 mm or more, depending on the specification). This prevents thermal stress from causing:
Cracking or leakage at joints;
Bending or deformation of the pipe wall;
Damage to fixed supports/brackets;
Overall system displacement leading to siphon failure.
Maintaining the Integrity of Negative Pressure Sealing in the Siphonic System
Siphonic drainage relies on full-bore negative pressure flow (negative pressure can reach -0.05 to -0.08 MPa). Any minor leakage or air ingress will disrupt the siphonic effect, resulting in reduced drainage efficiency or complete system failure. The expansion joint uses a dual-seal design (O-ring + sliding seal or bellows seal) to maintain airtightness during expansion and contraction, ensuring:
No air is introduced (preventing siphon interruption);
No gap leakage occurs (which is more pronounced under negative pressure);
Long-term stable operation of the system (HDPE service life of 50+ years).
Absorption of Pipe Vibration and Minor Displacement
Water hammer, air-water impact, or equipment vibration during drainage is transmitted to the pipes;
The expansion joint buffers these vibrations, reducing stress concentration on heat fusion/electrofusion joints;
It also accommodates minor building settlement or micro-movements from earthquakes (some designs provide limited angular or lateral compensation capability).
Facilitating Installation and Maintenance
Expansion joints are typically installed above the fixed support on vertical stacks or after horizontal
Quantity
| JF-SSJ50 |
| JF-SSJ75 |
| JF-SSJ90 |
| SSJ110（B） |
| JF-SSJ110 |
| JF-SSJ125 |
| SSJ160（B） |
| JF-SSJ160 |
| SSJ200（B） |
| JF-SSJ200 |
| SSJ250（B） |
| JF-SSJ250 |