Sacrificial anode installation requirements

Sacrificial anode installation requirements

1. The sacrifice anode is made of 22kg magnesium alloy, and a group is set every 250 meters, with two in each group.

2. The laying of magnesium sacrificial anode should be perpendicular to the pipeline, and should be selected in the place with thick soil layer, moisture and low resistivity. The minimum distance from the outer wall of the pipeline shall not be less than 0.5m, and the buried depth shall be the same as the buried depth of the center of the pipeline and not less than 1m.

3. The size of the sacrificial anode pit is 0.5×0.5×1.5m. Anodic packing bags must be made of natural fiber (cotton or gunny). It is strictly prohibited to use man-made fibers. The packing material can be packed indoors or on site. The thickness of the packing material around the anode should be consistent, and the thickness should not be less than 50mm. After the anode bag is in place, first water the packing material and then backfill it. During construction, ensure that the packing is dense and the anode is centered.

4. The reference electrode is used for the measurement of cathodic protection potential, and is buried in the center of the center line of the pipeline and as close as possible to the pipeline, with a horizontal distance of 100mm. Before the burying, the reference electrode and the packing material are soaked in water for more than 10 hours, and the surrounding soil is wet with water after the burying. Reference electrode packing bag must be made of natural fiber fabric (cotton or gunny bag), packing material can be packed indoors or on site.

5. Connect cables and pipes

Specific steps:

1) Pipe cleaning

2) Make a cut with a knife. (12 point direction, about 100mm2)

3) Heat the cut place, remove the PE layer with a shovel, and polish the epoxy layer with a wire brush to form a round smooth surface with a diameter of about 3cm.

4) will be around the PE softening place with steel file hair, will be raised rough scrape away (convenient repair).

5) Peel one end of the cable for about 3cm.

6) Press one end of the cable on the smooth surface with copper sheet, do thermite welding, and weld it on the pipe.

7) Remove burrs, spatter and welding slag from the welding place and check the welding quality.

8) After qualified, use hot melt glue to repair the wound here.

9) Two people work together. One person presses the cable on the pipe and the other person applies the melted rubber strip to the cable to create a smooth slope and form a transition to facilitate the installation and operation of the repair piece.

10) Repair the wound (according to the requirements of antiseptic repair).

A) Two patches should be used to repair the wound. First repair one and wait for it to cool down. Clean and coat the exposed cables.

Cooling reason: the first patch also needs to be beaten, to prevent the temperature is too high, when it will be scratched.

B) Install the second patch so that it is cross-installed with the first patch.

11) Connect the anode pack exposed cable to the cable connected to the wiring board with copper bushing, and use hydraulic pliers to press down both ends of the copper bushing and the middle three positions. After confirming the fixing, cover the heat shrinkable sleeve and heat it by the fire to make the heat shrinkable sleeve shrink and cover the copper sleeve.

12) Reserve serpentine bend for the cable exposed by the solder joint, and fix the serpentine bend on the pipe wall with rope or electrical tape to prevent the cable or solder joint from being freed by force.

13) The anode bag and the reference electrode are buried in the anode pit, and then the filling material is soaked with water and backfilled.

14) Clean two anode wires, solder joint wires, reference electrode wires, a total of four. As a reserve for later connection to the patch board.

Thermite welding process specification:

1) Peel the cable to an appropriate length, and use a wire brush to remove dirt and oxide scale;

2) Remove the coating on the welded steel pipe with a file and expose the metal substrate;

3) The mold is in place, and the cable is inserted into the bottom hole;

4) Put the metal piece into the mold cavity;

5) Pour flux and tamp;

6) Put the igniter and cover it;

7) Ignition welding

8) Remove mold, eliminate scum, and check welded joints.