Impressed current cathodic protection of circulating water pump

Due to the complexity of the structure, the diversity of materials and the harsh process conditions, the corrosion protection of the circulating water pump is much more difficult than that of the general structure. At present, the inner wall of circulating water pump is often protected by coating and impressed current cathodic protection, and the outer wall is protected by coating and sacrificial anode cathodic protection.

The protection objects of circulating water pump inner wall mainly include: pump shell inner wall, pump shaft, guide vane body, impeller, etc. Because of the narrow space in the pump chamber and the changeable process parameters, it is easy to install anode and control voltage and current by using coating and impressed current cathodic protection.

(1) DC power supply: DC power supply equipment can be installed in the control room or outdoor near the pump house. The installation shall meet the relevant requirements of electrical installation.

(2) Auxiliary anode: the auxiliary anode can be installed on the lower flange reserved on the water pump by bolt fixation, and the insulation resistance between the auxiliary anode and the pump body should be > 1m Ω. The anode cable shall be fixed and damaged during installation. The anode cable goes through the outlet hole of the pump cover and is sealed with packing and cable sealant.

(3) Reference electrode: fix the reference electrode flange on the reserved lower flange of the water pump with screws. The installation shall be firm without water leakage, and the electrode body or cable shall be insulated from the pump body (> 1m Ω).

(4) Shaft grounding device includes two types:

① The installation of conductive ring is generally made of brass, which can be made of semicircle butt joint or integral ring structure. The conductive ring is installed on the upper packing of the pump shaft of the diversion elbow to ensure that the water from the packing will not splash on the conductive ring.

② The installation of carbon brush usually adopts copper graphite brush, and its performance and quality shall meet relevant requirements. The carbon brush holder is fixed on the bracket with channel steel or angle steel, and the bracket is fixed on the pump body to ensure electrical connection.

(5) The cathode grounding and measurement grounding require firm welding and good conductivity.

(6) The lead wires of auxiliary anode and reference electrode passing through the outlet hole of pump cover are connected into the bus terminal box, and then the lead wires of DC power supply are connected to the corresponding terminals of DC power supply.

(7) The sacrificial anode in the current shielding part is fixed by bolts, and the sacrificial anode is installed at the position specified in the design.

Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services. 

Tel: +86 17568010262，0539-3712117.