Condenser cleaning determination operation methods, all here

"The condenser is easy to form scale in the pipeline after a long time of use. If it is not disposed of in time, these scales will affect the heat transfer effect, resulting in an increase in the condensing temperature of the unit, which in turn leads to a reduction in the cooling capacity and an increase in the power consumption of the unit. Therefore, the condenser should often be scaled off."

1. Calculation of condenser temperature difference

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

If the temperature difference at the end is calculated to be > 5℃, the heat exchanger can be initially judged to have scale, and when the temperature difference at the end is > 7℃, the scale is serious.

Example: Temperature difference of condensing end =36℃-32.3℃=3.7℃, temperature difference of evaporation end =12.1℃-9.7℃=2.4℃, it can be seen that the temperature difference of condensing end and evaporation end is small, the shell and tube heat transfer effect is good, basically no scaling.

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

Second, the main methods and operations of condenser cleaning

There are three main methods for removing scale in condenser:

Mechanical descaling

Chemical pickling and descaling

Electron magnetic water descaling

Here we introduce these three methods of cleaning and descaling.

1, mechanical scaling:

Mechanical descaling is to use a flexible shaft pipe washer (commonly known as a gun machine) to descaling the condenser of the refrigeration tube, which is suitable for vertical shell and tube condenser. (Speaking here, Xiaobian can't help but think of the scene many years ago when I held the gun rod in my hand and manually cleaned the condenser.)

Principle and method of flexible shaft tube washer:

The bevel gear scraper connected to the flexible shaft pipe washer is rotated and rolled to remove 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 by circulating cooling water, and the dirt such as scale and rust removed is washed into the pool.

In the descaling process, it is necessary to pay attention to the appropriate diameter of the hob selected according to the scale thickness of the condenser and the degree of corrosion of the pipe wall, and the length of the life that has been used, and the diameter of the hob selected for the first descaling is smaller than the inner diameter of the cooling pipe to prevent damage to the pipe wall, and then the hob close to the inner diameter of the cooling pipe is selected for the second descaling.

2. Chemical pickling and scaling:

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

Chemical pickling and scaling principle and method:

Clean the condenser with a prepared weak acid detergent to make the scale fall off.

Close the inlet valve, outlet valve, balance pipe valve, mixed gas valve, oil discharge valve and other valves on the condenser to stop the work of the condenser cooling pump.

The descaling solution is prepared in the pickling tank, and the pickling pump is started to make the descaling solution flow in the condensing pipe of the condenser for 24 hours, and then check the scale shedding situation to determine whether to continue cleaning. In general, the scale is basically removed after 24 hours. After the pickling pump is stopped, the detergent solution remaining in the pipe is repeatedly cleaned with clean water until it is completely clean.

3, electronic magnetic water descaling method:

The electronic magnetic water descaling method is suitable for all kinds of condensers, and it can descaling and prevent scaling without affecting the normal operation of the refrigeration system. And this method can not only effectively prevent the generation of new scale, but also can remove the original scale.

The working principle of electronic magnetic water device:

Calcium, magnesium and other salts in the cooling water flowing through the condenser are dissolved in water at room temperature in positive and negative ion states. When the cooling water flows through the transverse magnetic field of the magnetic water device at a certain speed, the dissolved calcium and magnesium plasma obtain induced electric energy, which changes its charge state, interferes with and destroys the electrostatic attraction between ions, and makes the crystal structure loose. Loose mud is discharged with the flow of cooling water.

The above three cleaning and descaling methods, the descaling method of the electronic magnetic water device is simple and easy, low labor intensity, not easy to damage the tube wall in the condenser, and can be carried out at any time. Pickling and mechanical descaling need to stop the normal operation of the refrigeration system, and should be arranged in the off-season of production.

Note: mechanical descaling method and chemical pickling descaling method, after the cleaning is completed, the air tightness test (pressure 1.8Mpa) must be carried out on the condenser to check whether there is leakage caused by damage to the tube wall during the descaling process. After the inspection is completed to ensure that the condenser is normal, the air in the condenser can be extracted (vacuumed) to put it into normal operation.