1. Groove type (clamp) connection
(1) The grooved connector (pipe joint) and
the depth of the steel pipe groove should meet the requirements of
"Grooved Pipe Joint" (CJJ/T156-2001). The working pressure of grooved
pipe joints with a nominal diameter of DN≤250mm is 2.5MPa, and
the working pressure of grooved pipe joints with a nominal diameter of DN≥300mm is
1.6MPa.
(2) Flexible joints should be used in
places with vibration and buried pipelines. Rigid joints should be used in
other places. When rigid joints are used, a flexible joint should be set every
4 to 5 rigid joints.
2. Threaded connection
(1) In the system, the inner and outer wall
hot-dip galvanized steel pipes or inner and outer wall hot-dip galvanized
seamless steel pipes with pipe diameters less than DN100 can be connected by a
thread. When the system uses inner and outer wall hot-dip galvanized steel
pipes, the pipe fittings can use forged cast iron threaded pipe fittings
(GB3287~3289); when the system uses inner and outer wall hot-dip galvanized
seamless steel pipes, the pipe fittings can use forged steel threaded pipe
fittings (GB/T14626). ).
(2) If the wall thickness of the steel pipe
is less than δ<Sch30 (DN≥200mm) or the wall thickness is less than δ<Sch40
(DN<200mm), threaded connectors shall not be used for the connection.
(3) When the pipeline adopts 55° tapered
pipe thread (Rc or R), the threaded interface can be sealed with PTFE tape;
when the pipeline adopts 60° tapered pipe thread (NPT), the sealant should be used as the seal
of the threaded interface; The sealing tape should be applied on the male
thread.
(4) Threaded unions shall not be used for
pipes with diameters> DN50, and single reducing joints shall be used at the
pipe diameter change.
3. Welding or flange joints
(1) Flange types can be divided into flat
welding flanges, bimetal welding, butt welding flanges, and threaded flanges
according to the connection form. Bimetallic welded steel pipe is a new type of
pipe. The flange selection must comply with steel pipe flanges (GB9112～9131), steel
butt welded seamless pipe fittings (GB/T12459), and pipe flanges are covered
with PTFE Gasket (GB/T13404) standard.
(2) If the hot-dip galvanized steel pipe
adopts a flange connection, a threaded flange should be used. When the system
piping adopts a non-corrosion-resistant inner wall, it can be connected by
welding. Pipeline welding should comply with the "Code for Construction
and Acceptance of Field Equipment and Industrial Pipeline Welding
Engineering".
Threeway Steel is known as a professional supplier engaged in manufacturing and distributing a wide range of steel pipe, and our headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
