The cartridge combines a long life depth type pre-filter media designed to give extended life by the removal of pipe scale, rust, waxes and asphaltenes that would otherwise cause the coalescent media to blind.

The pre-filter, together with the first and second stage coalescing medias effectively combine small droplets of water into large droplets which are then separated from the oil flow by gravity.

A final stripper screen is fitted to further minimise any risk of carry over of small droplets into the clean oil discharge.

The purified oil is discharged at the top of the housing, while the water is drained from the bottom.

Vokes 360/9 fuel oil filter coalescers each to handle a flow of 9m³/hr assembled on a module in duplex mode with a duplex TD43 pre-filter to handle exceptionally high solids content in the fuel. The module incorporates a fully automatic change over valve system.

The Vokes Filter Coalescer is suitable for installation in either bulk supply lines, prior to service tanks, or in the fuel lines to the prime mover. It can be used with or without other fine filtration equipment.

The Vokes Filter Coalescer is used on board ships, offshore installations, locomotives and in power stations as the main fuel purification equipment for either the prime mover, auxiliary equipment or main power generator.

Performance
For solids removal, an efficiency of 98% at 5µm is achieved. For free water removal it is down to 10ppm or below, depending upon the specific flow rating applied.

The effect of this high performance of water removal means the residual levels of soluble salts such as chlorides is virtually undetectable. This is of major importance in the case of those fuels which can be contaminated by saline water - for example water ballasted tanks on offshore platforms, fuel brought in by tanker or fuel stored in a marine environment. It also gives the opportunity of combining the Filter Coalescer with water washing.

Vokes 361/1 Lubricating Oil Filter Coalescer complete with pump. Several of these units, specifically designed to resist shock, have been supplied for purifying gearbox lubricating oil in submarine applications.P

The Vokes Filter Coalescer can be supplied by itself for the customer to pipe in to his system or in a variety of modules which can include pumps, heaters and control systems to provide self contained purification systems.

The Vokes Filter Coalescer is used in industries such as Power Generation, Sugar Refining and Marine, to provide the purification of lubricating oils in main and auxiliary steam turbines, gear boxes, stern tube and low pressure hydraulics systems. It is either used as a bypass system on the main tanks or from a bleed off the main oil supply line.

Performance
For solids removal, an efficiency of 98% at 5 microns is achieved.

The Vokes Coalescer will reduce free water levels in lubricating oil by 99% or more fo initial concentrations of around 8%. Free water can be reduced to better than 100ppm depending, of course, on the specific type of oil and the conditions encountered. So, for typical steam turbine applications at, for example, an oil flowrate of 7m³/hr this could mean that over half a cubic metre of water per hour would be removed.

Incorporation of the filter media in the coalescer cartridge eliminates the requirement for a separate pre-filter with its associated piping and valving. This is doubly important on a duplexed system and where available space is restricted.

The Filter Coalescer shown is a duplex 361/1 supplied to handle a flow of 1.2m³/hr of light crude oil. It is one of several units supplied to Allen Diesels for use on 6S37G diesel engines on a pipeline project for The India Oil Company.

Many Vokes Filter Coalescers have been supplied for use on board both surface and sub-surface vessels where both space availability and noise levels create serious difficulties.

The Vokes Filter Coalescer shown here is a 90m³/hr capacity unit supplied as part of a distillate fuel oil treatment module installed at Keadby Combined Cycle Power Station.

Many of these units are now in use around the world for Main Turbine Lubricating Oil Purification and Fuel Oil purification in countries as far apart as Australia to the UK. Supplied both as new equipment by the Steam and Gas Turbine and Diesel Engine manufacturer, and as upgrades to existing power plant.