Rotary Screw Compressor
Topic: Air Compressor
In the group of rotary air compressors, we have the screw compressor. This compressor is more effective than the popular reciprocating compressor, since it compresses air on 100% of each rotation, compared to only 50% of the stroke for a single-acting piston compressor.

 

This makes them not only more effective, but it also saves space and allows for great air flow outputs and higher pressures without taking up more space. The screw compressor has its name from the two screw rotating inside the compression chamber. They both intermesh with each other and when they do they form an air pocket between themselves and the inner wall of the compression chamber. Only one of the screws are connected to the compressor motor, whiles the other screw is driven by gears and just follows the lead screw around.

 

Another advantage with screw air compressors, is that they don’t rely on flow resistance to create compressed air. The air pockets, mentioned earlier, gradually decreases in size as they travel down the compression chamber. For this reason the screw compressor is called resistance free compressor. By placing several pressure exhaust valves, at various lengths down the compression chamber, we can quite precisely control the load and the pressure the screw compressor generates, by selecting different exhaust valves.

 

For internal cooling and lubrication, the air compressor uses air compressor oil. A measured amount of oil is injected and mixed with the intake air. This oil then forms a film inside the compressor that seals the gaps in between the screws and the compression chamber. The air compressor oil, which is still aerosol, is heated by the process and thereby extracts most of the heat from the compressor. The compressed air containing air compressor oil as well, is pushed out of the compressor and through an oil separator. In this oil separator, close to all of the air compressor oil is separated from the air. The now very hot oil is taken through an air cooled heat exchanger, where it’s cooled down before it is again injected into the intake air.

 

The hot air, normally around 185 degrees Fahrenheit is either taken through and air dryer, or directly stored in an air tank.

How to properly care for your air compressor
Topic: Air Comrpessor Maintenance
To ensure that you air compressor will work properly and deliver high quality air at good air pressures, there are a couple of things you should check regularly. Even though air compressors are simple and robust, they can, and will break down, if maintenance is neglected for too long. The problems with breakdown is that they always happens at the worst imagined time, when you are far away from any spare parts and desperately needs an air compressor to finish the work. The key word to avoid this situation is, preventive maintenance. By doing a few regurarly checks and parts replacement we can ensure a good working compressor with close to no possibility of braking down.

Daily maintenance:

• Check power cable and socket for damages
• Check air compressor for damages and faults
• Check oil level and refill as needed
• Make sure that safety devices is in order on air tools such as nailers, grinders, etc.
• Listen for abnormal noise and check for vibrations at start up.
• Check that the automatic cut-off switch stops and starts the compressor at the correct pressures
• Drain air tank, water trap, oil trap, and other system drains minimum once daily.
• Check for leakages once the compressor has filled the air system and the air compressor has paused.

Weekly maintenance

• Dust of the air compressor and clean the exterior with a damp cloth, make sure to keep the cooling ribs free of dust and dirt, since they have a big impact on the air compressors performance.
• Top up the compressor oil level and lubricator if installed.
• Lubricate all air tools by adding some compressor oil to the inlet connection before you connect the air and operate them fro 10-15 seconds.

Monthly maintenance

• Check the tightness of the drive belt, especially if the compressor makes a squeak on start up, by pushing it up and down. It should not flex more than approximately 1 inch in either direction.
• Function test the air relief valve/safety valve to make sure it it in working order and can move without any obstructions.

Every year

• An oil change is due every year if not more often. As the oil ages, it is exposed to oxidation, heat, water, etc. which all are factors deteriorating the oil.
• Once a year it is a good idea to change all filters as well. This includes the inlet air filter, in stream air filter, coalescing filter, etc.

Compressed Air Systems, Condensation Problems
Topic: Air Compressor Condensation

When designing a compressed air system, one problem is often overlooked and forgotten. This illusive problem causes corrosion, breakdown of air tools and equipment and reduces the quality of the compressed air leaving it useless. The root to all this problems is often air humidity, or water condensation to be exact.

When humid air is compressed, the airs dew point is reduced, causing water condensation to form at higher temperatures. The result of this is often the formation of water condensation. The condensations of water happens in the parts of the air system where the air pressures are at the highest and at sections where the air temperature is at its lowest.

Usually there is not much we can do to prevent condensation of water in pressurised air, but there are several ways to deal with it. This article will show you the most common methods of doing that.

Air dryers: To ensure absolutely dry compressed air, we can use an air dryer to extract all condensation from the air.

There are to principles of air drying:

1. Mechanical air drying uses a machine that cools down the compressed air well below the dew point of the air. These types of dryer often uses radiators with refrigerant flowing through them to cool down the air that flows by.
2. Chemical air dryer uses minerals and chemicals to extract humidity and condensation from the air. The chemicals absorb any humidity in the air, as the air flows through the chemicals. These dryer often consist of two, or more, cartridges. So that one cartridge can be used to dry the air, while the other is either being regenerated (removing humidity from the chemical) or is in standby.

Drains:

Drain valves is the absolutely easiest and most cost effective way of dealing with condensation. To get optimal effect using drain valves, all air pipes should have an incline from a drain point with a drain valve, in this way all condensation will be collected there which makes it easier to remove the condensation. Several drain points are often necessary to remove condensation throughout the compressed air system. Drain valves are also used in bottom of air tanks, pressure receivers, and like.

Membrane dryer/water trap (water filters):

These are sort of the compromise between air dryer and drains. It is important to remember that a water trap does not replace either a properly drained compressed air system, or an air dryer. The thing about water traps is that they filter out any aerosol water drops. The filter material is often made from borosilica-fibre (micro glass-fibre). As air passes through the filter water drops down to a size of 0.3 µ are filtered out by the filter and collected in the filter bowl, where it can be drained out. These filter are quite cheap and give increases the quality of you compressed air substantially.

Air Compressor Parts
Topic: Air Compressor Parts

To get the most out of your money when buying an air compressor, adding the right air compressor parts is the key. As a costumer you today have thousands of air compressors parts and tools available for you compressed air system. Some are quiet essential and will come in handy without any regards to what field of work or what you intend to user you air compressor for, while other parts are more focused on niches and can be considered special tools.

The basic start up kit for any aspiring air compressor owner could consist of the following:

• Recoil hose: This is a hose slightly thinner than ordinary air hoses. It is shaped like an old fashion telephone set wire, with coils to let it extend and retract as you pull on it.
• Blow gun: The blow gun seem simple, and frankly it is. Never the less, you can use it for anything around the house, in the garden, or in the garage. E.g. blow dry garden furniture after they have been cleaned, or after a rain fall; blow dust of of dirty car parts and tools; clean gutters and blow open clogged pipes; etc.
• Filters. Attach both a water/oil trap and an air filter to your compressor to ensure high quality with either dust particles or condensate and oil droplets. By installing filter you can safely use the compressor to do so much more, like airbrushing, dusting of fabrics and furnitures, inflating balloons, etc.

If you intend to use your air compressor mainly in the garage, these parts are handy to have around:

• Retractable air hose: this is brilliant in garages and workshops. No more time wasted on coiling up you air hoses, simply give it a pull and the retractable air hose reels itself in, thanks to the spring loaded mechanism. Not only does it save you time, it also keeps the hose out of harms way, making the workshop safer to work in and increasing the lifespan of the air hose.
• Impact wrench: This tool is a must have for anyone handling rusty old nuts and bolts. Use it for loosening stuck bolts and nuts. Get an impact wrench with torque adjustment, so you can be sure not to damage the screws threads.
• Air ratchet: This pneumatic wrench lets you easily tighten nuts and bolts in just a few seconds. It%u2019s also perfect for tight areas with little space to move.
• Tyre inflator with gauge. Use it to inflate car tyres, bike tyres, inflatable toys, sport equipment, etc. With the gauge you can be sure that all tyres have the same pressure, giving your car better handling.

For home improvement projects and carpenters these parts may come in handy:

• Sander: No matter what you do around the house, it always seem to be something that needs sanding. A pneumatic sander gets the job done, usually with less noise an electric model.
• Nail gun: Depending on what you are going to fasten, you can choose from different nail guns, or you can buy a nail gun sett, perfect for fastening large pieces of wood, mouldings, trimmings, etc. without the risk of hammer marks if you miss a nail.
• Air Grinder: Adjusting, sanding, precision cutting, etc. the air grinder is perfect and very handy to have around.

Airbrush Compressor Starter Kit
Topic: Airbrush Compressor

Airbrushing lets you create fantastic pieces of art, using only colour applied by a fine jet of air. If you replace the colour with fine grains of sand, you can even use it to etch in glass, creating long lasting decorations that won't fade. But airbrushing is not only limited to artists working in bakeries, tattoo studios, galleries etc. You can use it to apply spray tan and even airbrush makeup. It would be nice if you could just plug a siphon gun into whichever air compressor and start airbrushing, but it isn't that simple. That's why we will go through the basics of airbrush compressor in this article.

 

First up, noise level?

For those of you who taught that all air compressors are hideous loud monsters, think again. Today you can get air compressors not making more noise than you refrigerator while they're running. This of course comes at a cost so you should have a budget in mind before you continue reading.

 

If noise doesn't matter since your airbrush compressors is stored in the basement and you're airbrushing on ground floor, there are some money to save. And ordinary piston compressor with a 4-8 gallon air tank should do. You can purchase these practically everywhere for around $100-200. Done deal. Ingersoll Rand and Campbell Hausfeld are popular brands.

 

If noise matters a little, you could buy a mini air compressor these are small and usually generates less noise because of their size an nothing else. There are also models on the market labelled as silent compressors. My rule however is: if they are big, they are loud. So buying a normal piston compressor and expecting that you can use it while your wife or husband watches TV, is like hoping for a miracle to happen. If silent is what you want, or need, se below.

 

For those of you who have a professional studio where clients can't be disturbed, or you are airbrushing in the same room as the airbrush compressor is, a silent airbrush compressor is what you need. They cost roughly the double of a similar noisy air compressor would have, but in return, they are unbelievably quiet. These compressors have soundlevels of about 30-40 dB, which is considerably less, compared to a regular compressor with around 75-85 dB. Silent Air, Bambi, and Cole-Parmer are recognized manufacturers of quiet air compressors.

 

Second, air tank?

The air tank acts as a buffer, storing energy and letting the compressor stop once in while to cool down. So do you need one?

 

Airbrush Compressor with air tank is my choice if I am to do any airbrushing by free hand, without stencils. My argument here is that air compressors create pressure pulses as they compress air, these pulses are equaled out in the air tank, giving a more consistent and even spray of air and colour. If you wonder what the size of the air tank should be, you can roughly estimate it by saying you need one gallon of air tank, per CFM air consumption.

 

The no air tank option is for the air brush artist who uses airbrushing together with stencils, on projects where you could have used a sponge, or paint brush.

 

Third, air quality?

To achieve optimum results we need air of optimum quality and pressure. This is why I always use a water/oil trap, an air filter and a pressure regulator for my air brush equipment. A water/oil trap is also known as a coalescing filter and removes droplet from the air. The air filter is pretty cheap and removes almost all solid particles from the air. As close to my workstation as possible I set up my pressure regulator. By having it close I can easily adjust the air pressure to get the perfect spray out of my airbrush gun.

 

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