There are several methods to prevent rotation of the static ring in rotary mechanical seals

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The stationary ring of the rotary mechanical seal is installed in the gland, and the following methods are used to prevent rotation. 1. Floating static ring. An opening is provided at the tail end of the stationary ring, into which a anti-rotation pin is inserted to prevent the stationary ring from rotating. It features a simple structure, easy installation, and good floating performance of the static ring, which has led to its widespread use. Based on the installation location for anti-rotation pins, they can be divided into radial and axial types (Figure 41), among which axial anti-rotation pins are more commonly used. This design has a drawback: when cavitation occurs, the stationary ring can shift out of position, thereby damaging the seal. 2. Fixed static ring. Figure 21 shows several types of fixed static rings; due to their non-floating nature, special attention must be paid to the perpendicularity between the sealing surface and the axis line during installation. Its advantage is that the static ring does not shift when the pump is evacuated, making it more reliable. 3. Bonded static ring. Both of the first two types of static rings are equipped with sealing rings when installed in the gland, whereas the bonded-type static ring does not have such sealing rings; the sealing and anti-rotation between the static ring and the gland are achieved through adhesives. Due to the use of adhesives, the operating temperature and medium are limited by the properties of these adhesives; nevertheless, they are still used in many applications.