The large range of materials for Trisun mechanical seals makes it difficult to choose the right side combination. It is even more daunting to know that an incorrect combination of materials can lead to premature seal failure, resulting in considerable costs due to replacement of the dressing, pump downtime and possible damage to the equipment.
At least two opposing seal faces are required for each mechanical seal. They are usually classified as soft vs. hard or hard vs. hard. The first question to ask is whether faces need to have self-lubricating effects when trying to choose the combination?
The tradition of soft versus hard seal facial combinations in boundary lubricating and mixing modes requiring self-lubrication properties. The mechanical seal suppliers materials contact each other and good tribological pairings prevent significant damage from the stick faces.
In applications where the product enters and exits the mechanical seal faces as a liquid, most mechanical seal manufacturers are applied. The liquid’s properties are important because they have a great impact on the mode of operation of the lubrication. Such applications depend in particular on the viscosity of fluid for the selection of the right materials.
Fluid Viscosity
The viscosity of the fluid at working temperature is the most common consideration for mechanical seal suppliers. In general, low viscosity services operate more often in a boundary or mixed lubrication environments and are therefore best suitably sealed with a combination of soft and hard faces. The fluid creates a full liquid film lubrication mode for higher viscosity fluids and enables the combination of hard versus hard materials. However certain soft materials such as carbon, due to high viscous shearing forces between seal faces, which may cause the banding of a soft binder known as blistering, are not recommended in highly viscous liquids.
Material Compatibility
The faces of seals are subject to a wide range of process fluids. Some of these fluids are aggressive and chemically react with individual material components, like the base material, the binder or the filler.
Thermal analysis
Trisun mechanical seals materials react differently to the different external and internal temperatures on the seal face. The overall average face temperature is all influenced by external temperatures from sources such as pumped fluid, heating/cooling vest. Internal sources of heat such as friction and turbulence may cause local higher temperatures on the seal faces. These sources can lead to undesired thermal growth or retraction as well as possible damage to binding material.
Limitations of pressure
High operating pressure can push the limits of the mechanical properties of the face material of mechanical seal manufacturers. The materials should be evaluated for the location and extent of the pressure on the face. The assessment should examine whether the material’s strength is sufficient to avoid facial fractures, especially where the higher pressure is on the inside of the face.
Options in the face material
In the recent history of compatibility of carbon with the product fluid, a hard face material such as silicon carbide or carbohydrate has generally been selected against an inherently soft material, usually a type of blister-resistant carbon.
These are some major factors to be considered while choosing Trisun mechanical seals to avoid seal failure and high expenses.
