Mechinaical Seals

Non-contact seals for dirt and contaminants exclusion	Labyrinth type seal example

CF™- Labyrinth type seals use a non-contact seal design and are specifically designed to protect bearings from splashing water and other contaminants. These seals are not designed to seal pressure differentials or to seal against high fluid levels. They are primarily for contaminants exclusion. They consist of a stationary and a rotating ring and are made of engineering plastic or other high performance polymer materials.

Non-contacting rotary and stationary elements seal statically press-fit into the bore and/or on to the shaft and provide a restricted flow path through the controlled labyrinth gap based on a conic design and utilizes centrifugal force and gravity to prevent intrusion of contaminants into the bearing chamber. Unlike common lip seals, the labyrinth seal will not damage shafts and has a virtually unlimited life. It is very important that the CF™ - labyrinth type seal is mounted correctly. The bigger labyrinth diameter must be pointing to the contaminants.

Some of the benefits are:

• No contact, no wear and heat generated by the seal, no frictional power loss.
• Reduced maintenance cost since no wear, almost unlimited life.
• Low cost for mating parts, no hardening and surface grinding of the shaft required.
• Available in FDA compliant materials.
• Chemically resistant grades available.
• Overall a very economical sealing solution taking all the above in consideration.
• Low cost replacement for other expensive labyrinth seals in many applications.

FOR ROTATING SHAFTS

AMS Seals Inc.’s technical know-how is based upon years of experience in the mechanical seal industry. We solve difficult sealing problems. Our engineering expertise has been developed by designing and manufacturing seals for:

• Canning machines
• Industrial compressors & blowers
• Vacuum pumps
• Hydraulic systems
• Turbine engines
• Fuel systems
• Gear boxes
  We will custom design and engineer the optimium seal for your application.

STATIONARY FACE SEALS

STATIONARY FACE SEAL This stationary face seal is the most versatile seal. The design is simple, compact and economical and can easily be modified to make it suitable for a wide range of applications and operating conditions. This seal provides positive sealing and has excellent operating life within the limits of modern elastomers and plastics. APPLICATIONS The applications are almost limitless. Typical applications include vacuum blowers, compressors and pumps, which handle air, gases, oils, water, refrigerants, chemicals and food. CONSTRUCTION:

1. CUP: Standard 300 series stainless steel. Can be stamped for high volume, low-cost. The machined version is versatile and allows for bolt-in installation with O-ring seal for easy removal and overhaul. Carbon steel or special alloys are available. Reverse pressure capabilities can be provided at no additional cost. 2. SPRING: Standard wave spring type made of stainless steel although coil springscan also be used. Other alloys are available for special operating conditions. 3. WASHER: Usually 300 series stainless steel, other alloys available. This part can be eliminated with the fully machined version. 4. SEAL NOSE: Generally carbon graphite is used, but bronze and ceramic alloys are possible for special applications. Composite 2-piece assemblies are also common. The face of the seal nose is lapped flat within millionths of an inch and serves as the primary sealing surface. 5. RETAINING RING: Standard 300 stainless steel. Allows for easy take apart to overhaul and repair seal components. 6. ANTI-ROTATIONAL CHANNELS: Precision multi-weld construction for long life to prevent seal hang-up. O.D. is uninterrupted. 7. O-RING: Modern elastomers are available i.e. Fluorocarbon, Fluorosilicon, etc.including TFE encapsulated elastomers. 8. MATING RING: The other half of a face seal provides the wear surface of the seal nose. The selection of the proper mounting installation and materials is of utmost importance for satisfactory performance of the complete face seal assembly. See separate section.

CONTROLLED CLEARANCE SEAL

(FLOATING LABYRINTH)

CONTROLLED CLEARANCE SEALThe controlled clearance seal is also commonly called a floating labyrinth seal. The design principle of the seal is to have a precise control of clearance between the rotating shaft and the inside diameter of the seal ring. In operation, under ideal conditions, there is a pressure differential across the seal with the air side pressure being higher than the oil side. This differential prevents oil leakage and holds the carbon sealing ring against the oil side mating ring while the shaft turns freely within the sealing ring. APPLICATIONS Controlled clearance seals provide reliable shaft sealing where temperatures, speeds and limited lubrication prohibit the use of conventional face type seals. This is excellent for sealing gases at cryogenic or hot temperatures. The small compact design allows the use of this seal in centrifugal compressors, gas turbines and other high speed applications. CONSTRUCTION:
1. SEAL RING: Carbon provides long life through its excellent wear resistance and chemical and temperature stability.2. METAL RETAINING BAND: A compression fit with the carbon has two functions: provide tensile strength and to control the thermal expansion of the metal/carbon composite to closely match that of the rotating shaft to obtain a controlled clearance. 3. OUTER SHELL OR HOUSING: The metal housing provides a mating face for the carbon or a separate mating face can be used. 4. SPRING: Usually a wave spring holds the carbon against the mating face during start-up and shut down and allows for a small reverse pressure. Normal positive operating pressure holds the carbon in place. ADVANTAGES : Small Compact Size · Rugged · Long Life · Low Heat · Seal-Centering, Self-Aligning · No Elastomeric Parts · High and Low Temperature Capabilities · High Speed Capabilities · Unlimited Axial Shaft Movement MATING RING The correct mating ring design is vital to proper seal performance. Like the stationary face, the mating ring face must be extremely flat and smooth. It must be mounted on the shaft in a way that prevents slipping, leakage or distortion. Misalignment of the mating ring or excessive shaft runout can prevent the stationary and rotary faces from maintaining the perfect contact necessary for sealing. The configurations shown below are typical. Exact specifications are made by AMS Seal engineering after a review of each application's operating conditions and space requirements. Typical Configurations Clamped Ring For all practical purposes, this design imposes no temperature, pressure or shaft speed limitations. A shaft sleeve clamps the ring solidly to a step or bearing, providing positive drive and eliminating elastomers. The end of the sleeve and the shaft shoulder must be square to the centerline and their surfaces finished to approximately 125 micro in. rms. Clamped Ring with Elastomer This type is also clamped in place, but it uses a static elastomer for positive sealing of low viscosity fluids. Temperatures are normally limited to 450?F, depending on choice of elastomer. Note: All AMS Seal clamped rings utilize equal clamping areas on either side of the ring. This eliminates any twisting moments which tend to distort the ring.“O” rings, when used, are located in the shaft. This prevents any chance of the clamping action distorting narrow flanges on either side of the “O” ring groove. Shaft Shoulder When space is limited, a suitably finished shaft shoulder or end may act as a mating ring. Such an installation is not normally recommended because of the difficulty in establishing the proper surface finish. Balanced Ring This ring uses hydraulic pressure to maintain its axial location. P1 can exceed P2 by 500 psi max. “L” Shaped Ring, Packing Driven This is a low-cost ring for low pressure applications. It is sealed to the shaft and driven by the square packing. Solid Ring, Pin Driven A pin provides positive drive and an “O” ring seals between the mating ring and shaft. These rings are suitable for high reverse pressures (P2 > P1).

Unitized Shaft Seal

Design The unitized “Take-Apart” shaft seal was specifically designed to offer ease of assembly and field maintenance without any modification to existing equipment. The design permits easy component replacement, such as o-ring or spring, if necessary. This feature practically eliminates the need to replace the entire seal if one component shows wear. The “Take-Apart” design promotes the concept that special materials for o-rings and mating rings can be substituted for standard materials upon request. Features • Factory assembled for ease of installation • “Take-Apart” design for quick, easy repair • Simplicity for dependable performance • Suitable for a wide range of operating conditions • Capable of reversible pressure

Construction The standard materials of construction are: a carbon seal nose, Ni-Resist mating ring, and Buna-N o-rings and gaskets. All metal hardware is stainless steel. Other materials for o-rings, gaskets, and mating rings are available to meet special operating conditions. Capabilities These seals are designated for effective oil and lubricant retention over long periods of time under rugged conditions. Our standard units operate at 0 to 10 psi; 10 to 250 F temperature: and up to 3000 FPM speed at seal face. Special materials can be supplied to withstand higher operating pressures and temperatures, when requested.