"After long-term use of the condenser, it is easy to form scale in the pipeline. If it is not dealt with in time, these scales will affect the heat exchange effect, resulting in an increase in the condensing temperature of the unit, which in turn leads to a decrease in the cooling capacity and an increase in the power consumption of the unit. So the condenser should be descaled frequently.”

1. Calculation of the temperature difference of the condenser

The focus of condenser cleaning is to pay attention to: chilled water inlet and outlet temperatures, cooling water inlet and outlet temperatures, condensation pressure, and evaporation pressure. We can calculate the end temperature difference, and convert the condensation pressure and evaporation pressure into the corresponding condensation saturation temperature and evaporation saturation temperature. If you can query the condensation temperature and evaporation temperature on the touch screen, the value is the corresponding condensation saturation temperature and evaporation saturation temperature.

For example: the temperature difference at the condensing end=36℃-32.3℃=3.7℃, the temperature difference at the evaporating end=12.1℃-9.7℃=2.4℃, it can be seen that the temperature difference between the condensing end and the evaporating end is small, the heat exchange effect of the shell and tube is good, and there is basically no temperature difference. Scaling.

In addition, you can also look at the color of the copper tube of the condenser. If you can't see the original color of the copper tube, the scaling is very serious and needs to be cleaned in time.

Second, the main method and operation of condenser cleaning

There are three main ways to remove scale from the condenser:

Mechanical descaling method

Chemical pickling and descaling

Electronic magnetic water descaling method

Below we introduce these three methods of cleaning and descaling.

1. Mechanical descaling:

Mechanical descaling is to use a flexible shaft washer (commonly known as a gun-passing machine) to descale the condenser of the cooling pipe, which is suitable for vertical shell-and-tube condensers. (Speaking of this, the editor can't help but think of the scene many years ago when I took the gun barrel and manually cleaned the condenser.)

Principle and method of flexible shaft washer:

The bevel gear-shaped scraper connected to the flexible shaft pipe washer rotates and rolls to remove the scale in the riser of the condenser from top to bottom, and the heat generated by the friction between the scraper and the pipe wall is cooled with the help of circulating cooling water, and at the same time, it will remove the Scale, rust and other contaminants are flushed into the sink.

In the process of descaling, it is necessary to pay attention to the thickness of the scale of the condenser, the degree of corrosion of the pipe wall, and the length of the service life to determine the appropriate diameter of the hob, and the hob selected for the first descaling. The diameter should be appropriately smaller than the inner diameter of the cooling pipe to prevent damage to the pipe wall, and then select a hob close to the inner diameter of the cooling pipe for the second descaling.

2. Chemical pickling and descaling:

The chemical pickling and descaling method is suitable for vertical and horizontal shell and tube condensers (steel pipes). The normal operation of the condenser must be stopped during the descaling process to ensure safety.

Principle and method of chemical pickling and descaling:

Use the prepared weak acid scale remover to clean the condenser to make the scale fall off.

Close the inlet valve, liquid outlet valve, balance pipe valve, mixed gas valve, oil drain valve and other valves on the condenser, and stop the cooling water pump of the condenser.

Prepare the descaling solution in the pickling tank, start the pickling pump, make the descaling solution circulate in the condenser tube of the condenser for 24 hours, check the scale falling off, and then determine whether to continue cleaning, generally after 24 hours The scale is basically removed. After stopping the pickling pump, repeatedly wash the descaling solution remaining in the tube with clean water until it is completely clean.