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Application Of Dry Gas Seals In Methanol Pump
Jun 28, 2017

Dry gas seals is a controllable gap of the non-contact mechanical seal, sealed between the end of the film. Dry gas seals to meet the high PV value, long life and high reliability requirements.

Dry air gas seal is a new type of shaft seal for gas sealing applications, which is a non-contact seal. Dry gas seals have a variety of structural forms, but the basic principle of the same as the mechanical seal, is perpendicular to the rotation axis of one or more pairs of sealed end to achieve sealing.

In recent years, the application of dry gas seals has become increasingly popular, not only large-scale turbine centrifugal compressor commonly used dry gas seals, in some devices on the key pump, especially the use of liquid seal is very difficult to pump, began to use dry gas seals.

Pump dry gas seals from the structure can be divided into three categories:

(1) TM11A dry gas seals: the use of "gas seal" instead of the traditional "liquid seal", in the sealed low temperature, volatile media with high reliability;

(2) TM11B dry gas seals: the use of two sets of dry gas seals in series, the middle of the gas seal. No pollution of the process medium, to ensure the high purity of the pumping process media;

(3) TM02C dry gas seals: dry gas seals and contact with the mechanical seal in series, the main mechanical seal, dry gas seals for the standby seal. After the main seal failure, dry gas seals for a short time to play the main seal, to prevent the process medium to the atmosphere leak.

Because the sealing liquid and the medium are easy to vaporize the material, and the media contains many impurities, the general mechanical seal is easy to have a negative impact, according to the pump process parameters and the actual conditions of the characteristics of the following two transformation program:

(Figure 3, Figure 4), so as not to be affected by the vaporization of the medium, and by the main seal (1) in order to overcome the medium volatilization caused by mechanical seal end of the dry friction, the main seal using dry gas seals, sealed type selection TM11A dry gas seals (Figure 3, The gas is filtered so that the dry gas is sealed by the end face of the clean gas.

(2) In order to make the impurity of the medium do not affect the normal work of the dry gas seals, the front buffer is used for the flushing, in order to make the structure simple, directly using the pump outlet filter after the clean medium as a buffer, while the pump medium and seal Add a spiral seal between the buffer to block the impurity from entering the buffer and protect the dry gas seals from working properly.

Dry gas seals work, the main seal gas pressure 0.7MPaG pipe network low pressure nitrogen, filtered by the filter, the gas filtration accuracy of 1μm, by the vertical pressure regulating valve, flow meter into the sealed cavity. In order to ensure the safe operation of the pump, when the pressure of nitrogen as low as 0.4MPaG, by the self-standing control valve installed after the pressure switch instrument control methanol pump interlocking shutdown.

Dry gas seals is the front of the buffer from the pump outlet pipe cited over the media liquid - methanol, filter the filter through the impurities contained in the particles, filled with dry gas seals front buffer chamber to protect the dry gas seals The sealed end face will not be contaminated by the viscera medium.





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