The model 501C and 502C metal bellows mechanical seals are designed to give greatly improved service life over pusher seals.
Because they are rotating bellows, they are expecially well suited for handling problem fluids such as drilling muds and crude oil containing sand. In refineries, they can handle oil streams containing FCC catalyst fines when both seal faces are properly designed.
Nested Ripple design with advanced TIG welding techniques insures macimum bellows strength and fatigue resistance. It all but eliminates stick-slip failures.
Hastelloy "C" is used in both the 501C and 502C bellows. It is far superior to 316 Stainless Steel, Alloy 20, or AM350 in corrosion resistance, stress corrosion cracking resistance, and yield strength. Alloy 20 has a yield strength of 35,000 psi while Hastelloy C has a yield strength of 58.000 psi, a 66% increase! And that is where it counts; in the bellows.
Drive set screws are Hastelloy C on both the 501C and the 502C. This reduces set screw galling problems that can result with 316 Stainless Steel set screws. The 66% greater yield strength also insures that your Allen wrench will not "strip out".
The Champion metal bellows seal will not fret the shaft or sleeve because it has no dynamic (sliding) "O" ring. All pusher seals (seals with springs) have common dynamic "O" rings. This means that you can mount 501C and 502C metal bellows seals directly on the shaft and save the cost of a sleeve.
The Champion 501C and 502C metal bellows seals are balanced with ou the need of a stepped sleeve as required by all balanced pusher seals. You save money: a stepped sleeve costs more than a straight sleeve.
Rotating bellows are self cleaning. No plugged convolutions as with stationary bellows. This design makes the Champion 501C and 502C ideal for handling suspended solids.
The 501C and the 502C normally have (3) set screws, (1) "O" ring and the rotating assembly, a total of 5 parts. The convential pusher seal rotating assembly consists of 4 set screws, 12 springs, 1 retainer, 1 rotating face, 1 "o" ring, 1 PTFE anti-extrusion ring, 1 backup ring and 1 snap ring. Twenty two parts (22) versus just five (5) parts.
The standard stationary face is premium qualtiy Hexoloy SA-80, known as sintered alpha silicon carbide. The is one of the most corrosion resistant seal face materials on the market today. It is especially suited for corrosive paper mill streams, strong acids such as hydroflouric (HF), and boiling caustics. With its superior hardness, thermal conductivity, and coefficient of friction, it will out perform tungsten carbide and 99.9% ceramic.
The standard rotating face is a carbon-graphite-resin seal face. It has good strength, chemical resistance and coefficient of friction.
The method of face attachment to the end adapter is a key to thermal face stability. A seal face that does not stay flat when it heats up is a common cause of premature seal failures.
Because the bellows spring does not have the overcome "O" ring friction drag, as in a pusher seal, the spring load can be lighter in the 501C and 502C bellows than in a pusher seal design. This can result in decreased seal face wear rate.
The bellows produce even face loading, superior face tracking and less frictional heat. Result: the Champion 501C and 502C Hastelloy "C" metal bellows out performs pusher seals.