FUGESCO

INC 
Mechanical Seals
Hydro Electric
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TURBINE SEAL AXIAL TYPE

 

Our axial type seals are specifically designed for application to hydroelectric turbines and large water pumps for sewage handling, filtration and irrigation, etc.

 

Our axial type seals are self-aligned, balanced split face seals capable of with-standing the heavy torques, pressures, shaft movements (radial and axial) and thrusts associated with such shaft systems.

 

Depending on the turbine's operating conditions, many custom arrangements can be used.

 

The seal components are usually split to ease installation. A basic turbine seal consists of a base ring and a cover ring forming a cavity which houses the sealing rings. The cover ring is secured to the base ring, which in turn bridges the gap between the turbine shaft and the head cover. The base ring also serves to house the inflatable seal when required.

 

The sealing action takes place between two mating rings; one stationary, the Sealing Ring, the other rotating with the shaft, the Seat Ring. The axial direction of the sealing action prevents damage to the turbine or pump shaft, since the wear is taking place between the Seat and the Sealing Rings, and not on the shaft.

 

The Sealing Ring is held in contact with the Seat Ring by a spring force and the hydraulic force of flushing water. These properties balance the seal at all times.

 

The purpose of the inflatable seal is to allow for the replacement or inspection of the seal faces without dewatering the turbine. The shaft must be at rest when the inflatable seal is in use. The design of FUGESCO's inflatable seal does not require any special tools or fixture for vulcanization. Our design uses male and female ends and can be installed in much less time than the vulcanized type.

 

A flow of clean water, free of abrasive particles must be maintained throughout the seal, to provide cooling, lubrication and to reduce wear of the sealing surfaces. Water should be filtered to ensure that impurities larger than 25 microns are removed, in order to prevent abrasives particles entering from under the seal. The clean water supply must be at a higher pressure than the water pressure under the seal. It is recommended to install an automatic differential pressure system with the water supply, maintaining a constant pressure difference above that of the pressure under the seal.

 

On certain models of our seals, the water is injected directly between the mating faces. By controlling the seal water flow in the annular profile between the faces provides the benefits of a double seal since it allows control of the seal's environment through cooling, lubricating and cleansing, as impurities are prevented from entering in between the mating faces.

 

All of our seals include an assembly kit (consisting of: eyebolts, jacking screws and hex keys for use during assembly or disassembly of the housing parts), an a-ring splicing kit, flange sealant, silicone grease, a piping connection identification plate and three copies of the installation, maintenance and operation manual.

 

In order to regulate the pressure differential between the shaft seal and the turbine, a seal water control panel complete with an automatic differential pressure regulator can be supplied with each seal. The positive pressure differential is necessary to prevent abrasive particles from entering the seal chamber.

 

OPERATIONAL LIMITS
Max. turbine operating pressure: 1034 kPa (150 psi)
Max. recommended barrier water pressure 20-70 kPa (3-10 psi) above turbine pressure:
Recommended water filtration 25 microns
Radial shaft dislocation ± 1.3 mm (0.06")
Axial shaft dislocation ± 3 - 25 mm (0.125" — 1")
Shaft/sleeve finish 63 RMS
Shaft sizes up to 1800 mm (70")