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STARK AIR DRYERS / PuRIFIERS


The Stark Expello Air Dryer/Purifier with its advanced micro-glass fibre technology provides an extremely effective, self cleaning, long life filter. The filter automatically purges every 5 minutes, and is thermostatically controlled for year-round efficiency.

The filtering system removes 100% of all solids larger than 1 micron in size and virtually all compressor blow-by oil. The coalescing is achieved by a coil which allows the moisture contained in the compressed air to be removed.

An audible signal indicates when the filter element needs to be changed. Otherwise no maintenance is required and the accumulated moisture is dumped from the system by the regular operation of the Stark Expello valve.

The system consists of 2-parts; the Stark Expello Air Dryer/Purifier and then the Expello Valve. It has the following features:

This 2-part system consistently provides cleaner, drier compressed air than competitive desiccant type or after-cooler units.

The Stark Air Dryer/Purifier is both a filtering and coalescing system. It removes 100% of solids larger than 1 micron in size and 99.9% of all of the compressor "blow by" oil. Moisture is also removed by the filter/coalescer. Any remaining moisture is purged from the system through the Expello" Valve located on the air tank.

The Stark System provides clean, dry air 100% of the time. The Stark Air Dryer/Purifier System meets high air use requirements better than any other system on the market today.

The Stark System is designed to operate efficiently during long periods of continued compressor engagement, providing clean, dry, oil free air under high air volume usage. Unlike competitive desiccant systems, the Stark System does not require a purge cycle to provide clean dry air. Desiccant systems require reverse air flow through the desiccant bed during a purge cycle to clean the desiccant. Under periods of continued use a purge cycle cannot occur.

Vehicle applications such as waste management trucks with pneumatic lifts and compactors use compressed air almost constantly. Highway and construction vehicles using pneumatic equipment in addition to their air brakes also need constant, clean, dry air for long periods of time. Desiccants can't supply it.

The Stark Air Dryer/Purifier System also requires less maintenance than other filter systems. The Stark Air Dryer/Purifier System is fitted with a "Whistle Stop" element change indicator. A whistle signal lets you know when the filter needs replacement.

The specially designed micro-glass filter/coalescer element maintains its efficiency 100% of the time. As microscopic particles of dirt and carbon accumulate on the inside of the element, it keeps right on removing and ejecting oil and water; even during constant air use.

The Stark Air Dryer/Purifier System delivers the cleanest down stream air of any air dryer on the market today. In fact, it is hundreds of times cleaner than the air we breathe.

The Stark Air Dryer/Purifier is both a filtering and coalescing system that purifies the vehicle's compressed air. The filter material is strong enough to remain stable. It totally resists chemicals, acids, water and other possible attackers in the compressed air system.

When air enters the unit, the inner wall of the glass fiber filter/coalescer element captures solids-carbon, dirt, and dust. As the air passes through the element fibers, water and oil particles are coalesced or merged together into drops. Small droplets coalesce to form larger drops. The heavy or large drops are then forced downward by air flow and gravity to the sump where they are ejected by the automatic drain valve.

Remaining water vapor is removed by a high-efficiency heat transfer cooling and condensing coil.

Sustained high compressed air temperatures may result in water vapor carry over to the number one (wet) tank. The Expello" Valve, part of the "Stark System", then takes over removing moisture from the air tank.

The space age, vacuum formed,micro-glass fibers of the Stark filter element are also designed not to break down even under extreme pressures. No chance of loose fiber particles entering the air system. This progressive cleaning and drying process repeats constantly. The solids slowly accumulate inside the element until it needs to be replaced . The element is typically replaced annually. If replacement is needed before that time, a whistle indicator sounds. Replacement is inexpensive and easy.

Removes Moisture

2-part system, Stark Air Dryer/ Purifier and Expello" Valve, removes air system moisture.

Low Cost Maintenance

Service is done with the air dryer on the vehicle. Four bolts are easily removed from the bottom of the unit to change the filter element. Desiccant type air dryers may require removing the entire unit from the vehicle for service.

High C.F.M. Flow Rate-36 C.F.M

The Stark Air Dryer/Purifier's efficient space age design of unique vacuum formed glass fibers, yielqs the highest C.F.M. flow rate. Aftercooler and desiccant dryers would have to increase their uni size and capacity to reach this level of flow.

Efficient Oil Removal

The vacuum formed micro glass fiber filter also enables efficient removal of oil from the air system.

The Most Efficient Solids Filtration

A 99.9% solids removal rating makes Stark the most efficient air dryer/purifier available.

Best Overall Efficiency

The unit works at full efficiency 100% of the time, delivering consistent results. The "Whistle Stop" element change indicator will signal if recommended service is exceeded.

Small Overall Size-Lightweight

The compact 6 by 12 inch unit can be mounted in hard to fit locations. Weighing only 12 pounds, the air dryer/purifier helps reduce total vehicle weight. One Size Fits All! The Stark Air Dryer/Purifier basic model fits both governor and unloader controlled air systems making it the most versatile air protection device on the market. It can be used on virtually any mobile application including off highway construction and mining equipment.

Heater Options Cover All Voltage Requirements

The Expello" Automatic Drain Valve is used to eject contaminants from the system. Heater options with an automatic thermostat for cold climate conditions cover all voltage requirements, and can be used on positive or negative ground systems.

Time Tested

The Expello" Automatic Drain Valve has been in use for over 40 years; proven by millions of miles on thousands of vehicles. To keeps costs and inventory at a minimum, the Stark Air Dryer/ Purifier and Expello" Drain Valve use the same inexpensive rebuild kit.

Stark Diagram

Stark Part Numbers

F995111
 12 Volt
 Electronic Actuated Expello Valve
 1/4" NPT
F995112
 24 Volt
 Electronic Actuated Expello Valve
 1/4" NPT
F995019
 12 Volt
 Air Dryer Purifier
F995018 24 Volt
 Air Dryer Purifier
F995242 Coalescer Filter Kit

THE PRINCIPLES OF STARK MICROGLASS FIBER FILTER/COALESCER TECHNOLOGY

Oil and water particulates in compressed air are usually present in the following forms:

1. sprays, droplets 500 micrometers and larger;
2. mists, droplets about 50 to 500 micrometers in size;
3. fogs, droplets from 1 micrometer to 50 micrometer;
4. smoke, 0.1 to 0.5 micrometer;
5. fumes 0.001 to 0.01 micrometer liquid molecules. (vapor)

Source of the water is relative humidity in atmospheric air that is drawn into every air compressor through its inlet. Much of the hydrocarbon particulates enter the air stream in the same manner. These are even present when nonlubricated compressors are used. With an oil-lubricated unit, shearing action of the piston rings against the cycler walls and high heat of compression convert much of the crankcase oil into aerosols that bypass the compression rings and enter the air stream.

Solid particulates also come into any compressor through the strainer, which can only keep out the larger particles. If the strainer were too fine, it would not permit high volumes of atmospheric air to be drawn into the cylinder without restriction.

An aerosol removal method that is extremely efficient involves a combination of direct impaction, inertial impaction, diffusion (Brownian motion) and coalescence. The first three enhance the latter. The coalescing of the liquid particulates being the main method of removing oil and water contaminants.

Where solid and liquid particles are present together, there will always be a film of dirt particles around the liquid ones. Removal requires filtration prior to coalescing for best results.

Most colaescing takes place at low air pressures and low velocities with liquids having high surface tension, with systems having a large difference in densities between oil and water, with the cleanest liquids, and at room temperatures.

All these perfect coalescing conditions rarely exist at the same time within a compressed air system, so coalescence must be induced by mechanical means. If one liquid is present, that liquid's own surface tension value would be the greatest influence on its coalescence from the air. Where the oil and water are present, then the interfacial tension value between the two determines their ability to coalesce. The more the surface tension and interfacial tension, the better they will coalesce. Directional changes of the air stream are helpful in causing coalescence and impingement. Airflow through porous media also is effective. In many cases, where the particulates are "invisible" in the air stream, the action seems to miraculously change part of the air itself into a liquid emulsion.

Experience has shown that the best way to coalesce liquid particulates is to control airflow and velocity through a fibrous bed with a predetermined porosity with minute strands, and permanent electrostatic charges. To keep the size of the element small and prolong its useful service life that is, to allow air to flow without undue restriction while particles are loading on its surface - a medium that has the highest .possible ratio of air passages (pores) to media material (strands) is most desirable. Further use must be made of a material that has great strength so as not to crumble and migrate downstream. It must be inert to chemicals, acids, and other possible attackers in the compressed air. The material must also be nonwettable.

Glass strands with a mean diameter of 0.5 micrometer fulfill this need perfectly. An element using various pore sizes to "prefilter" the air before it enters the media, the medium itself and an outer layerfine enough to prevent any migration of the medium - all should be held in place by very strong bonding. This bonding will not only sufficiently support the delicate strands in their intended position, but will keep the media compacted between the prefilter layers and afterlayers. Thus, the air stream cannot move the strands out of place, even under pulsating shock conditions of airflow. This will achieve the depth-type maximum coalescing of aerosols.

An element designed with a prefilter with tiny pores in a cloth-like layer, such as a vacuum formed glass fiber tube, enhances coalescing of the liquids because the prefilter removes very small solid particulates. The distance between the random microfibers of inert strands located in the next layer through which the air travels, and which is at right angles to the air stream, is very small. The strands must be very fine, 0.5 micrometers, this material is effective as a coalescerof liquid droplets from 5 micrometers down to 0.01 micrometer. This structure removes small particulates by diffusion (Brownian motion) and direct or inertial impaction.

Such a design results in an almost continuous film of liquid on the outer barrier that holds in place the densely packed layer of random microfibers. By gravity, the liquids migrate down the outer layer dropping off the bottom of it and into a sump, out of the compressed air system.

Additional Condensing AND Coalescing is accomplished by using a porous bed of very open mesh, like a knitted wire material of an inch or more in depth. This is called through-flow, depth-type coalescing. Mainly, it is the coils thickness and diameter that will determine the velocity at which the air will flow through it. Very low velocities must be maintained.

Coalescing

As air enters the wire mesh coil , the liquid particles come into contact with the random wire strands and collect on them. As this continues, the liquid on the wire grows, making it easier for additional droplets to contact it. This method is very dependent on the high surface tension of the liquid. It also depends on the wire coil being highly wettable. The droplets spread on the wire and cling there through adhesion, until by gravity the droplets fall off. Also, if dirt is not first prefiltered before the coil media, entrained dust interferes with coalescence. Moderate coalescing results in such a unit.

The Stark Air Dryer/Purifier uses a combination of Filtration and Coalescing to remove dirt, carbon , oil, and free water down to "fumes ". Additional coalescing is done via a "condensing coil" or wire mesh scrubber which is protected from oil and dirt by the microglass fiber filter/ coalescer element. In this stage the fumes are cooled , condensed, and coalesced. This entire (4) stage progressive cleaning and drying process has constant repeatability and only the accumulation of solids inside of the element cause the need for filter element replacement. By removing oil, carbon, dirt and water, this system provides year round protection from sludge and varnish build-up necessary for trouble-free brake system operation. Microglass fiber technology has brought the results vehicle operators need to keep air systems clean, at a cost they can easily afford.

The Stark Air Dryer/Purifier is designed to remove 100% of the solids larger than 1 micron in size and 99.9% of all of the compressor blow by oil as well. Approximately 97% of all water (by volume) is removed by the special microglass fiber filter/coalescer. However, under sustained high air temperatures the condensing coil stage gets hot and may not be able to get rid of the heat fast enough. When this condition exists some vapor may carryover to the number one or wet tank. Remember,these same high temperatures cause after cooler type units to fail and desiccants to start to regenerate or give up moisture as well. Competitive units are not effective at removing oil and trapping of small harmful solids. In the case of desiccant type Dryers, media migration (desiccant fines) released into the air stream may even contribute to an increase in solids contamination in the air system. Stark Air Dryer/Purifiers deliver the "cleanest" down stream air of any Air Dryer on the market today. In fact, it is 10 times cleaner than any other vehicle compressed Air Dryer and hundreds of times cleaner than the air we breathe.

Due to extreme high air temperature conditions, Stark recommends the use of the VH or va systems. The VH is a Heated Expello. Automatic Air Tank Drain Valve and the va is a non-heated Expello. Automatic Air Tank drain valve with monitor. Harmful solids and oil are removed by the most efficient Air Dryer/Purifier available, and now vapor carryover is eliminated from the #1 tank by the Expello Valve. Now for the first time you have a total Compressed Air Protection System from P.M. to P.M., even with marginal installations and poor system maintenance.


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