Description of the selection of seals for high viscosity media

High viscosity media are grease, sulfuric acid, gear oil, cylinder oil, styrene, silicone oil, and residual oil.
It is characterized by good wettability when the viscosity is high, but too high will affect the floating of the moving ring and increase the transmission torque of the spring. When the viscosity is too high, the liquid film is not easily formed between the sealing faces, the lubricating performance is poor, and the sealing ring is damaged.
The requirements of the seal: the friction pair material is wear-resistant, the spring should have sufficient capacity to overcome the resistance generated by the high-viscosity medium, avoid the temperature of the seal chamber is too low and cause the viscosity of the medium to increase, and the seal chamber is required to be insulated or heated.
Mechanical seal selection
1. For general viscosity medium, when p≤0.8Mpa, single-end unbalanced seal is used; when p>0.8Mpa, balanced seal is used. When the viscosity of the medium is 700-1600Mpa.s, it is necessary to increase the design of the drive pin and spring to resist the increase of the shear force due to the increase of viscosity. When the viscosity is more than 1600Mpa.s, it is necessary to strengthen the lubrication, such as single-end sealing. The flushing fluid is supplied to the outside, or the double-faced seal is passed into the insulating fluid. 2. Static double-face seal with pressurized flushing system. 3. A combination of hard to hard friction pair materials, such as silicon carbide-silicon carbide, or tungsten carbide-silicon carbide. 4. Consider the insulation structure to ensure that the viscosity of the medium does not increase due to temperature drop.