Mechanical seals are a versatile type of rotary shaft seal. Although they have a wide range of applications, sometimes their useful life can be quite difficult to predict. Moreover, several factors play a part in their premature and sudden failure which is often considered a result of worn faces and resistance between the rotor and stator.
All types of mechanical seals have one part in common: the face. These faces within a mechanical seal, categorized as stationary and moving faces, help in maintaining adequate contact during seal operation.
Faces must be made of compatible materials and should also complement the working conditions they’re being used for. Their relative motion, coefficient of friction, and the ability to withstand temperature and pressure should be able to maintain the integrity of a machine. Different types of materials are used to make these faces, some of which are specialized to work under abrasive conditions.
The primary purpose of using differently built seal faces is to maintain sufficient fluid between the faces to keep them lubricated and leak-proof.
Here are the three most common types of materials used to make robust mechanical seal faces:
1. Silicon Carbide
Silicon carbide is a cutting-edge ceramic substance. It’s hard, extremely wear resistant, and comes with good mechanical properties. This material can withstand high temperature, thermal shock, and resistive abrasion.
Silicon carbide mechanical seal faces can work under temperatures as high as 2550°F (1400°C). Above this point, the free silicon inside the compound will melt and decay.
Silicon carbide seal faces are widely used in midstream applications. They are often used as a mating face pair adjoined with a carbon ring due to its exception PV properties. Silicon carbide seal faces move in a direction against one another under high viscosity conditions such as thick crude oil. We recommend tout drive designs for seal rings to prevent hang-ups caused due to abrasion between softer metal parts in a seal retainer.
2. Metallized Carbon
Highly robust and long-lasting, carbon-graphite or metallized carbon is a self-lubing material that has dynamic industrial application when used in manufacturing mechanical seal faces. It has a versatile seal face and mating rings made of hard substances such as silicon carbide, alumina, or tungsten carbide.
It has supreme chemical and abrasion resistance, making it suitable for operating with corrosive substances such as hydrofluoric and nitric acids. It’s important to note the there are various graded carbon seals available that cater to different fluid characteristics. Metallized carbon seals are used in all types of industrial units, especially in the chemical industry.
Metallized carbon seal faces are compatible with various metal faces and ceramic counterparts. Some of them have a polished finish that’s designed to work inside water pumps. Carbon base seals are also used in all kinds of mechanical shaft seals, rotary steam joints, and compressors.
3. Tungsten Carbide
Tungsten carbide is sturdy material extracted from high percentage of tungsten carbide particles bonded together by a yield-y metal. The most common types of binders used to make rings for tungsten carbide seals include cobalt or nickel.
Mechanical seals faces made of tungsten carbide are a tough with good wear resistance. Seals with nickel rings are used in midstream pipe applicationsas they offer enhanced protection against power or thermal shock.
Quality Mechanical Seals and Services
Our team at Robco of America offers an extensive range of mechanical seals catering to all kinds of industrial and commercial application. Our mechanical seals variety includes custom designed seals, Cartridge Mechanical Seals, Assembly Seals, among many others.
Call us at 800-662-0585 for more information.