use Mechanical seal for kettle What is the effect of overheating?

According to different working conditions and media properties, mechanical seals include high and low temperature resistant mechanical seals, high pressure and corrosion resistant mechanical seals, granular media resistant mechanical seals, and mechanical seals suitable for easily vaporized light hydrocarbon media. Mechanical seals with different structure types and materials shall be selected according to different uses.

The clearance between one or two end faces indicates that the distance between the two end faces is too large. When the two end faces are tightly closed, the clearance will occur. The common reason for end face separation is the rapid evaporation of imported mechanical seal medium. For example, water, especially in hot water systems or liquids containing condensed water, will expand when evaporating, separating the two ends. Pump cavitation and seal blockage may also be the cause of seal end clearance. In this case, it is not caused by vibration and coupling misalignment, because it is not enough to make the end face notch. Reducing the end face temperature is a common method to prevent the end face from being damaged by rapid evaporation of media. At the same time, it is also conducive to the use of materials with good thermal conductivity, such as nickel based cemented carbide, copper impregnated graphite, etc. In addition, use a balanced mechanical seal, or use a special corrosion resistant mechanical seal gland to inject liquid from the outside for cooling, or directly cool the seal in the cavity. It is very effective in reducing the temperature of seal face.

When the mechanical seal fails, the end face of the friction pair often leaves small radial cracks, or radial cracks with blisters or even cracks. This is caused by overheating of the seal, especially the sealing surface of ceramics and hard alloy is vulnerable to such damage. Poor medium lubricity, overload, high working temperature, high linear speed, improper combination of paired materials, etc. The superposition of any one or several of these factors will generate excessive friction heat. If the friction heat is not released in time, heat cracks will occur at the seal of dyeing and finishing machinery, causing excessive wear and high leakage. In order to solve the problem of seal overheating, in addition to changing the end face area and reducing the load, it can also be solved by using a static seal and increasing a guide sleeve to forcibly cool the circulating fluid to guide the sealing face, or by opening a hydrodynamic groove on the sealing face. There are many tiny hot spots and isolated discoloration areas on the friction end face, indicating that the seal is deformed under the influence of high pressure and high temperature. For the thermal deformation of the end face, the general calculation method is not allowed, and the finite element method should be used to calculate, so as to improve the design of the seal ring.