Mechanical seal flushing solution

News | 2019-05-31 14:09

Mechanical seal flushing solution

Flushing the mechanical seal is an effective measure to control the temperature of the mechanical seal and extend the life of the mechanical seal. The purpose of flushing is to take away heat, maintain and improve lubrication, prevent liquid film from vaporizing, prevent accumulation of impurities, and prevent the formation of air bags.
According to the rinsing form, it can be divided into internal rinsing and external rinsing. The internal rinsing is performed by using a conveying medium, and the external rinsing is performed by introducing external substances.

Internal flushing
Working principle: The sealed medium is introduced into the sealed cavity from the outlet end of the pump through the pipeline.
Practical scope: used for cleaning media, p1 is slightly larger than p inlet. If the temperature of the media is high or there are impurities, you need to install coolers, filters and other equipment on the pipeline to process the media.

Backwash
Working principle: The sealed medium of the working host is used to introduce the sealed cavity from the outlet end of the pump, and then flow back to the pump inlet through the pipeline after flushing.
Practical scope: used for cleaning the media, and p in <P1 <P out. When the temperature is high or there are impurities, coolers, filters and other equipment can be installed on the pipeline to process the media.

Full flush
Working principle: The sealed medium of the working host is used to introduce the sealed cavity from the outlet end of the pump through the pipeline, and then flow back to the pump inlet through the pipeline after flushing.
Practical range: for cleaning media, and p1 is close to p in and p out, the cooling effect is better than the first two

Outside flush
Working principle: Introduce the cleaning fluid of the external system to the sealed cavity to flush the mechanical seal.
Practical scope: The pressure of the external flushing liquid should be 0.05-0.1 MPa greater than the sealed medium, which is suitable for high-temperature media or solid particles. The flow of the flushing liquid must not only ensure the cooling effect, but also the flow of the controller.
Avoid excessive erosion of seals due to excessive flow and shorten their service life. For this reason, the pressure of the sealed chamber and the flow rate of the flushing need to be controlled. Generally, the flow rate of the cleaning and flushing liquid should be less than 5m / s;
For liquid washing liquid containing particles, the flow rate should be less than 3m / s. In order to meet the above flow rate, the pressure difference between the washing liquid and the sealed cavity should be <0.5MPa, generally 0.05 ~ 0.1MPa
For double-end mechanical seals, 0.1-0.2MP can be taken. The inlet and outlet positions of the flushing liquid should be set close to the rotary ring side and slightly closer to the sealing end face. The washing liquid can be introduced tangentially or multi-point washing,
To avoid mechanical seal erosion or deformation caused by uneven cooling. In special cases, hot water or steam can be selected as the washing liquid.