Working pipe: steel pipe
Insulation: Polyurethane foam
Outer protection pipe: high-density polyethylene (HDPE) pipe
(7) Joint insulation:
a. The insulation of directly buried pipe joints should be carried out after the pipeline installation is completed and the strength test is qualified.
d. After the installation of the outer sheath of the joint is completed, all must be tested for air tightness and should be qualified. The pressure of the air tightness test is 0.02MPa, the pressure holding time should not be less than 2min, and the seal is carefully checked with soapy water after the pressure is stable, and no bubbles are qualified.
(8) The directly buried steam pipeline must be equipped with a tidal discharge pipe, the steel outer protection pipe must be externally anti-corrosion, the on-site interface welding of the working pipe should be made of argon arc welding, and the weld should be 100% radiographic flaw detection.
【Supplementary explanation】Argon arc welding: argon shielding gas is passed around the arc welding to isolate the air from the welding area and prevent oxidation of the welding area.
【Single Choice】Regarding the installation requirements of the casing of the heating pipe passing through the structure, the correct one is ( )
A. The gap between the casing and the pipeline should be filled with high-grade cement mortarB. The waterproofing casing is installed as soon as possible after the concrete pouring of the structure
C. The casing through the structure should be flush with both ends of the structure D. The casing through the floor slab should be 50mm above the slab surface
2. Installation requirements for heating pipe network accessories
1) Installation of pipe support and hanger
The installation requirements for pipe supports and hangers are as follows:
(1) The production and installation of pipeline support and hanger is the first process in pipeline installation, which should be completed before pipeline installation and inspection. The installation position of the support and hanger should be correct, the elevation and slope should meet the design requirements, the installation should be smooth, and the burial should be firm.
(3) The elevation of the supporting surface of the pipe support can be adjusted by adding a metal backing plate, the backing plate shall not be greater than two layers, and the thick one should be placed below, and the backing plate shall be welded with the embedded iron parts or steel structure, and shall not be added between the pipeline and the bearing.
(8) The installation of the fixed bracket shall meet the following requirements:
(3) The contact surface between the fixed bracket card plate and the bracket structure should be solid, but should not be welded, so as not to form a "dead spot" and cause accidents;
(4) The root of the steel bracket such as the fixed bracket and the guide bracket should be waterproof pier.
2. [Single Selection] In the accessories of the heating pipe network, the one that can withstand the three-way displacement and load is ( ).
A. 弹簧吊架B. 弹簧支架C. 球形补偿器D. 刚性吊架