JT Series Insulating Joint Selection

Shenyang Yongye YY - JT Series Insulating Joint Selection

The insulating joint is the essential pressure component necessary for steel pipeline cathodic protection system, broadly applicable to steel pipeline cathodic protection systems. Our company’s insulating joints adopts a unique design based on referencing foreign latest product structure according to ASME BPV  Code Sect Ⅷ Div.ⅠAppendix2 design specifications and ASME B31.3 design code, to overcome problems of inadequate rigidity, prone to leak, unable to be buried under ground short service life, ete. The insulating joints have realized buried parts maintenance-free function and allow a service life matching the pipelines.

Design specifications：ASME BPV  Code Sect Ⅷ Div.ⅠAppendix2  GB150

Design code：ASME B31.3  GB50253

Technical characteristic：

Dimensions ：DN15～DN1200

          Pressure grade：PN1.6～PN40.0MPa

          Service life：same as the service life of pipeline

          Applicable medium：oil, gas, water, chemical feed ,mineral slurry

          End slope meatus：in accordance with  ASME B31.4 and the regulations for welding technics

          Installation place：buried-levelly under the earth

 Quality inspection:100% insulating resistance value test：≥10MΩ@DC 1000V

           100% insulating intensity test：no breakdown or arc for one minute @5000V 50Hz 

           100% hydraulic pressure testing pressure: 1.5 times of designed pressure

           100% air-tight testing pressure：equivalent to designed pressure

           100% non-destructive testing：to 100% the crack detection of the weld line of all the butt-connectors by ray accordance with ASME BPV Code Ⅷ UW-51，App.12，App.6 or JB4730, other welding line are 100%

detected by ray or magnetic power.

           100% surface of end slope examination

           100% hardness test on weld joints

           5% submerging electrolysis fluid insulating intensity testing：≥6MΩ

           5% hydrostatic pressure plus bending test ：longitudinal stress 72%×the regulated test bending intensity.

           5% hydrostatic pressure fatigue test：1MPa～85% hydrostatic pressure test for 40 cycles

           100% the thickness of coated dry velum test

           100% visual and dimensional check

           5% coat adhering test

Material s characteristics：

Assembled parts：according to ASTM A694 F52/JB4726

           Stub end：same with pipeline material

           Insulating material：ASTM D709 G11 or GB1301.1-1998 high strength epoxy glass

           Filling material：high strength epoxy resin

           Sealing material：rubber fluoride 26

           Sealing stickiness：silicon rubber

           Internal & external surface anti-corrosion insulating material：two-component solvent-free epoxy coating, anti-corrosion thermal contraction bushing.

Field Installation Requirement:

1、 There should not be any weld dead hole present within 50M range of the intended installation of the insulating joints.

2、 After completion of insulating fittings connected with pipeline, hoisting the pipeline within 5M proximity is disallowed to prevent excessive bending moment.

3、 The insulating joints shall not be used as the offset component for thermal strain

4、 When the insulating joints are pressure-tested together with pipeline, the maximum pressure rise rate shall not exceed 0.5MPa per minute.

5、 Insulation joint installed on the straight pipe on the ground or underground, shall be 30 meters away from the elbow and set the anchor pier.

6、 Avoided to be installed on the perennial stagnant water where  buried installation.

Special material and pressure not present in the Table can be calculated as per ASTM Strength Calculation and manufactured in accordance with order. Along with technology and process advance and development, the data in the Table may change.