There are several ways by which the mechanical seal flushing fluid enters the seal chamber

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There are two ways for the flushing fluid to enter the sealed chamber: single-point flushing and multi-point flushing. Single-point flushing: The flushing fluid flushes the seal through an outlet, and this can be done in three ways: radial, axial, and tangential (Figure 63). Radial flushing: The sealing fluid flushes the friction pair vertically in a radial direction (Figure 63a). It has a simple structure and is a commonly used method. However, the flushing volume should not be too large to prevent the graphite ring from being flushed out of the notch. Axial flushing (Figure 63c): The sealing fluid enters the sealing chamber axially, preventing erosion of the graphite ring, and can be used in pumps handling corrosive media. Tangential flushing (Figure 63b): The flushing fluid washes the friction pair in a tangential direction, which is a better method compared to single-point flushing. The single-point flushing structure is simple, but the temperature distribution around the seal is uneven. To avoid erosion of the graphite ring, the flow rate of the radial flushing fluid entering the sealing chamber should not exceed s, and the diameter of the flushing holes should not be less than 5 mm. To this end, the flushing volume must be controlled. Tangential flushing helps to even out the temperature around the sealing surface and also reduces erosion of the graphite ring; it is a method that is highly recommended. Multi-point flushing (Figure 64): The flushing fluid enters the sealed chamber simultaneously through multiple small holes around the circumference, thereby performing a flushing function. Multi-point flushing overcomes the disadvantages of single-point flushing, resulting in a more uniform temperature distribution around the friction pair. However, its structure is relatively complex, requiring the addition of a flushing ring with 6 to 8 small holes, each having a diameter of 3 to 4 mm. Multi-point flushing is used in media that are prone to vaporization, as well as in situations with high PV values where significant frictional heat is generated. The flushing holes should be located as close as possible to the friction pair in order to better dissipate heat. Single-point flushing cannot be directed directly at the graphite ring (stationary ring), nor can it be placed too far away from the friction pair, as this would weaken the flushing effect.