John Crane T-2 single outside mounted mechanical seal. Bellows refers to rubber boot which seals against the impeller shaft. Bellows type seal is FTI's most used seal. Will handle most acids and non-crystallizing chemicals. Standard bellows seal comes with F31 grade carbon, regular ceramic (unless noted) and Viton elastomers.

Bellows type seals should not be used in pump applications when the suction pressure exceeds 5 PSI over atmospheric pressure (14.7 PSI). Use the multi-spring seal.

Bellows seals are not normally recommended for liquids, which crystallize, but when the pump is fitted with a cooling collar assembly it may be used. Cooling collars should also be used when pumping hot liquids over 140^oF.

Cooling collars require 1-2 GPH of fresh flush water at 1-2 PSI of pressure. Do not exceed 2 PSI.

Multi-Spring Type

John Crane 8B2 single outside mounted mechanical seal. Multi-spring refers to 8 small springs used to properly balance this seal to provide higher suction pressure handling and longer life. Multi-spring seals will handle from 15 PSI to 65 PSI above atmospheric pressure (14.7 PSI). A higher priced seal than the bellows or double the multi-spring seal should only be used when necessary. Standard multi-spring seals come with F31 grade carbon, high purity ceramic and Viton elastomers. When the application requires Kalrez elastomers the multi-spring is the only seal which can be fitted with it.

The multi-spring seal like the bellows seal is not normally recommended for liquids, which crystallize, but when the pump is fitted with a cooling collar assembly, it may be used. Cooling collars should also be used when pumping hot liquids over 140"F.

Cooling collars required 1-2 GPH of fresh flush water at 1-2 PSI. Do not exceed 2 PSI.

Double Seals

John Crane T-21 double outside mounted mechanical seal. Double seals consist of l-inboard seal (faces contact pumped fluid) and 1-outside seal (seal contacts fresh flush water). Standard double seals have F31 grade carbon, regular ceramic (unless noted), and Viton elastomers. Since only the inboard seal faces contact the fluid it is not necessary to change out the outboard seal faces when ordering a special seal.

Double seals are used for all liquids which crystallize or are slightly abrasive. Double seals can also be used for hot liquids over 140"F. When fresh water is turned on the double seal will protect the pump from run dry damage. Very important that when the pump is running, the flush water to the double seal is turned on or pump damage can occur. Use of a flow switch is recommended.

Double seals require 1-2 GPH of fresh water at 5-10 PSI over pump discharge pressure. Minimum 25 PSI for the GP11 and 35 PSI for GP22/32.

Vapor Barrier System

Is used with the bellows or multi-spring seal only when fresh flush water is not available to keep seal faces clean when pumping liquids which crystallize. Vapor barrier system when full, will also protect the pump from run dry damage. The vapor barrier system recirculates clean liquid through a cooling collar seal area and back to the reservoir to be cooled.

Restrictor Bushing

Is used with the bellows type seal and pressure collar for handling abrasive solutions or corrosive / abrasive solutions. By pressurizing the pressure collar with clean water we force liquid through a Teflon bushing into the pump. Water enters the pump at a rate of 2-3 GPH.

Pressure collar should be pressurized 5-10 PSI over pump discharge pressure. By forcing liquid into the pump, we prevent the corrosive/ abrasive fluid from coming in contact with the mechanical seal. Thus expensive hard face seals are not necessary. Note: It is critical to keep pressure on the seals even when the pump is off to prevent the product from entering the seal chamber.

Special Note: When installing any mechanical seal, we do not recommend using petroleum products for lubricating the elastomer components. Only use a 50/50 water dish soap solution. Using a petroleum product will prevent the elastomer components from adhering to the impeller shaft. Seal will spin on the impeller shaft and damage both components.

Finish Thompson Inc. – (.2/20/95 – LAN)