AS-C413 Customized Double Cartridge Mechanical Seal

AS-C413 customized double cartridge mechanical seal is dual seal in cartridge form

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What are the requirements for the sealing fluids used for flushing
Auxiliary facilities for mechanical seals refer to lubricating, cooling or temperature-regulating, flushing, purifying, diluting and flushing away the leakage medium to improve the working environment of the mechanical seal by means of flushing, cooling, filtering and separation.

The primary mode of operation of all ancillary facilities of mechanical seals is flushing.
For self-flushing, the flushing fluid is the sealed medium itself. For circular flushing and injection flushing, the sealing fluids and the sealed medium are different, and some requirements are put forward for the sealing fluids.

1)The flushing fluid should be clean, non-corrosive, compatible with the medium in the pump, and have good lubricity at working temperature. 2) The flushing liquid will not affect the product quality if it enters the pump, and if it leaks out, it will not pollute the environment and have no other adverse effects. 3) The flushing liquid entering the pump will not affect the operation of the pump. For example, pumping down and cavitation are not caused. 4) The flushing fluid has good thermal conductivity and can conduct heat out in time. The washing temperature should meet the working requirements. 5) The price of the flushing solution should be low. The amount of flushing should be controlled and not too much, which is necessary for energy saving and consumption reduction. The choice of which fluid to use as the flushing fluid is flexibly controlled according to the specific conditions.

For example, for an alkylation unit that uses concentrated sulfuric acid as a catalyst, the ordinary 104-type mechanical seal has a shorter service life because of severe corrosion. It is impossible to use self-flushing, so injection flushing has to be used. So what fluid to choose as the flushing fluid? Diesel certainly is OK, but the device cannot be used without water, which will affect production and aggravate corrosion. According to the requirements of the flushing liquid, the reaction product of the device is finally selected - a mixture of carbon 4~carbon 9. The mixture does not reduce the concentration of the acid after it is sealed into the pump, and enters the reactor through the pump together with the acid, and only a small amount of reaction product circulates between the pump and the reactor. The mechanical seal device’s working environment is improved and the working life is prolonged.

For another example，what kind of fluid is better in choosing hot oil pump mechanical seal’s flushing fluid and its reasons？

The primary mode of operation of all ancillary facilities is flushing. As for which fluid to choose as the flushing fluid, it can be flexibly controlled according to specific conditions. This article talks about how to choose the flushing fluid of the hot oil pump mechanical seals.

The most typical units in hot oil pumps are atmospheric tower bottom pumps and vacuum tower bottom pumps in atmospheric and vacuum distillation units, and oil slurry pumps in catalytic cracking units.Their common features are that the temperature is as high as 360~370°C, that the medium contains impurities, and that the viscosity is high.These constitute one of the difficult problems of pump maintenance work in refineries. In order to change the working environment of the mechanical seal, injection flushing is often used (referring to the single mechanical seal).

So what fluid is used for flushing? Some factories use light diesel oil as flushing fluid. Although it is easy to obtain in refineries and has good other properties, it is a product after all, and it is not economical to mix it with the above-mentioned heavy oil.More importantly, it is easy to cause the pump to evacuate. As we all know, light diesel oil is a component at 170-360°C, more than 50% of the components vaporize at 270-300°C, and more than 90% of the components vaporize at about 350°C. Obviously, light diesel oil is not suitable as flushing fluid for the above-mentioned thermal oil pump.Using the raw material oil (wax oil) of the catalytic device as the flushing fluid overcomes the above-mentioned shortcomings, which not only reduces the production cost (wax oil is not a product), but also avoids pumping out. In order to reduce the viscosity of wax oil, its temperature can be controlled at about 100°C. Atmospheric pressure tower bottom pumps and vacuum tower bottom pumps can also use wax oil as flushing fluid if they use a single end face seals.