Structure	Steel pipe-- insulation layer--HDPE outer protection pipe
Steel pipe standard and material	1. GB 20#, Q235B 2. ASTM A53 GrB 3. API Spec 5L 16Mn, X42-X80
Steel pipe process	1. Seamless, 2. Spiral steel pipe( SAW) 3. Straight steel pipe(ERW)
Material of insulation layer	Bayer/Basf Germany
Foaming technology	CFC-free water
Material of HDPE	Shanghai Jin Fei, Qilu petrochemical,Tianjin zhongsha petrochemical(level 100)
Application	1. district heating 2. district cooling 3. crude oil transportation 4.cogeneration project
Laying mode	Mainly used for direct buried, and can be used in trenches.
Specification	DN25-1800mm(1 inch-72 inch)
Medium temperature	Less than 120℃( accidental peak 140 ℃)
Medium pressure	Less than 2.5MPa
Advantages	1. Unique trinity structure 2. Low thermal conductivity, small the heat loss 3. Water-proof 4. Anti-corrosive
Related products	1. The pre-insulated pipe with alarming line 2. Joint materials 3. Insulation fittings

Main Indexs of Pre-insulated Pipe
Product Name	Product Indexes	Reference Standard	Unit	Standard Requirement
Finished product	Steel pipe without thermal insulation layer	CJ/T114-4.4.1	mm	150-250
	Increasing rate of HDPE outer protection pipe	CJ/T114-4.4.2	%	≤ 2
	Axis eccentricity	CJ/T114-4.4.3	mm	see clause 4.4.3
	Expectation of life	CJ/T114-4.4.4.1	year	120℃ 30 years
	Shear strength(170℃,1450h after aging)	CJ/T114-4.4.4.2	MPa	(23±2℃)>0.12 (140±2℃) >0.08
	Shock resistance	CJ/T114-4.4.5	3kg/2m	see clause 4.4.5
	Resistance value between alarm line	CJ/T114-4.4.6	MΩ	more than 20MΩ
Outer protection pipe	Density	CJ/T114-4.2.3.1	kg/m3	≥940
	Elongation at break	CJ/T114-4.2.3.4	%	≥350
	Tensile yield stength	CJ/T114-4.2.3.4	MPa	≥19
	Longitudinal shrinkage rate	CJ/T114-4.2.3.5	%	≤3
	Long term Mechanical properties	CJ/T114-4.2.3.6	80℃ 4.0MPa	>1500h free from damage
	The difference of the melt flow rate	CJ/T114-4.2.3.2	g/10min	≤0.5
	Carbon Black content	CJ/T114-4.2.3.1	%	2.5±0.5
Polyurethane insulation layer	Density	CJ/T114-4.3.2	kg/m3	≥60
	Average pore size	CJ/T114-4.3.1	mm	≤0.5
	Percentage of close area	CJ/T114-4.3.1	%	≥88
	Compressive strength	CJ/T114-4.3.3	MPa	≥0.3
	Water absorption	CJ/T114-4.3.4	%	Immersion in boiling water 90 minutes, bubble water absorption should be not more than 10%
	Coefficient of thermal conductivity before aging	CJ/T114-4.3.5	w/(m.k)	≤0.033
	Cavity	CJ/T114-4.3.1		≤1/3 the thickness of insulation layer
Working steel pipe	Seamless steel pipe(≤DN150)	GB8163	20#	Up to standards
Working steel pipe	Spiral steel pipe (≥DN200)	GB/T9711 or SY/T5037	Q235B	Up to standards

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