The scale samples were taken from the pump seal chamber and titrated with hydrochloric acid. In the process of titration, it was found that the scale of the high-temperature oil pump was not gradually dissolved as expected, but only a small part of the scale was dissolved by hydrochloric acid. According to the initial speculation, the main components of scale should be carbonate and sulfate, most of which will dissolve in the titration test of hydrochloric acid, but the result of titration test is not consistent with the speculation. Therefore, the water hardness of scale sample was analyzed.
It can be found that the mass concentration of suspended matter is about 5 times of the control index, while the mass concentration of COD is more than 20 times of the control index. Therefore, it can be concluded that the abnormal mass concentration of COD and suspended matter is the main reason for scaling in cooling water.
COD is the use of chemical oxidants (such as potassium permanganate) will be oxidized substances in water (such as organic matter, nitrite, ferrious salt, sulfide, etc.) oxidation decomposition, and then according to the amount of residual nitriding agent calculated oxygen consumption, is an important indicator of water pollution degree. The smaller the value is, the less polluted the water is. The excessive COD concentration provides a hotbed for the breeding of all kinds of bacteria, thus producing biological slime. As the increase of biological slime leads to the blockage of cooling water pipeline, biological slime stiffens at high temperature, and it is very difficult to dissolve biological slime with hydrochloric acid, which is consistent with the difficulty of dredging cooling system with hydrochloric acid in maintenance site.
Structural analysis of mechanical seal
After entering the cooling chamber, the cooling water will directly flow into the following three places:
The clearance between the moving ring and the shaft sleeve.
The gap between the outer circle of the shaft sleeve and the inner circle of the water sleeve.
③ The gap between the outer circle of the water jacket and the circle inside the static ring bellows.
