Hydrostatic mechanical seal-

Hydrostatic mechanical seal

　2017-09-22　　

Hydrostatic mechanical seal:

The hydrostatic mechanical seal is to introduce the sealing liquid or the sealed self-medium with sufficient pressure to balance the pressure load of the end face into the sealing end face to form a static pressure fluid film with sufficient lubrication and cooling effect on the end face of the seal. Figure 3-1 is a typical structure of a hydrostatic mechanical seal.

The self-pressurizing groove type in Figure 3-1 is to open a number of holes on the outer periphery of the stationary ring and communicate with the annular groove on the end surface. The fluid film on the end surface has high rigidity and stable working performance, but it is necessary to prevent the small holes from being blocked. The self-pressurizing step type is processed into a step shape on one end surface. The fluid film on the end face is less rigid, and it is difficult to grind the end face. One end surface of the self-pressurizing conical surface is a convergent conical surface, and its liquid film stiffness is lower than that of the self-pressurizing groove type and the self-pressurizing stepped type, and the hydrostatic pressure is distributed in a parabola along the radius. The three are all relying on the pressure of the medium to form a static pressure fluid film on the end face, and the thickness of the fluid film changes with the fluctuation of the medium pressure, which is suitable for the occasion where the working pressure of the medium is more stable than that of neodymium.

The fluid lubrication structure of the external pressure groove type seal is similar to the self pressure groove type. The difference is that the outer periphery of the static ring does not communicate with the medium, and the sealing liquid is introduced from the outside into the end face annular groove to establish the end face Hydrostatic fluid film. This structure is suitable for the situation where the working pressure of the medium fluctuates, but lubrication should be selected

Figure 3-1 Typical structure of hydrostatic mechanical seal

The fluid with good performance and compatible with the medium is used as the sealing liquid, and an external sealing liquid circulation adjustment system must be equipped at the same time.

The fluid static pressure type mechanical seal requires the input lubricating medium pressure to be appropriate, so the control is more complicated, and it is less used now.

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