Sizing your compressor correctly is a very important process. A compressor that is undersized for your operation will overwork and in most cases, run hotter than normal. If a compressor spends the majority of the day (especially piston compressors) running hard to try and keep up with demand, heat often causes damage and can add to excessive moisture build-up. If a compressor is oversized, the cost of running can be significantly higher than it should be. If you have a screw compressor, they prefer to be running enough to get up to their recommended running temp, as well as prevent costly multiple electric motor starts. Variable speed screw compressors can also be hugely beneficial in operations that have a constant air demand that in most cases fluctuates. A variable speed compressor can save a significant amount of energy cost in the correct setup.
As a rule, small single phase compressors are best suited to lighter use, and 3 phase compressors are recommended in commercial, higher demand applications.
Bayteck Systems will calculate your demand and help to size your energy efficient compressor according to your operation, as this varies in each application.
Benefits of a screw compressor are the ability to run a 100% duty cycle, lower noise levels, a smaller operating pressure band and the air they deliver tends to be cleaner and dryer with their standard features. All screw compressors sold by Bayteck Systems come with a built in after-cooler, and there are many different variations of screw compressor available to suit individual applications. The most common screw compressor sold comes with a built-in refrigerant air dryer and are mounted on a large air receiver tank. These are usually referred to as a ‘full feature’ compressor.
Piston compressors are very economical in the correct application, but as they have a purely mechanical operation with higher levels of pump friction, they need time to rest to cool.
Service schedules vary depending on usage and the type of compressor you run. As a general rule, all compressors should be serviced at least annually, but within their manufacturer recommendations. Screw compressors have built in hour meters in which usage can be monitored, and depending on the recommended manufacturer service intervals, can be completed on an accurate schedule. A lot of screw compressors require an oil and filters change at 2,000 hours of run time, but some brands can run up to 4,000 hours between servicing.
Piston compressors should have oil and filters changes at least once per annum, and with harder and longer running hours, should be completed at least every 6 months.
Compressors do have a variety of different serviceable components, in which some services involve more time and additional replacement parts. In-line filtration elements should also be on a replacement schedule along with your compressor.
Air compressor preventive maintenance isn’t as simple as replacing the oil and filter elements, there are many components that need to be tested and checked during your service to ensure it is in good running order.
Condensate is a natural and unavoidable part of the compressing of air. As all ambient air has a degree of humidity, when this air is compressed into a much smaller than usual contained space the moisture particles connect and form water droplets. This condensate can pass through your airlines and enter tools and equipment causing costly damage. If you are experiencing moisture build up in your compressed air system, there are ways of removing this:
Ensure your compressor isn’t running too hot as heat can cause water particles to remain as airborne droplets, and can contribute to excessive moisture build up.
Install a good quality water separator. A centrifugal separator basically spins the air in a cyclone motion as it passes through, and forces any moisture particles to condense into water that is expelled out it’s in-built drain. This is a simple option that is relatively inexpensive and can remove the majority of water from compressed air.
Add a dryer to your operation. There are many different types of dryer available, but the most common type is a plug-in refrigerant dryer. Most compressed air dryers cool the compressed air down to a cold level, about the same level as your standard household fridge. The immediate cooling of the warm compressed air causes moisture particles to condense and quickly turn to water, which is purged off into a drain system. Other dryer types are absorption dryers which contain moisture absorbing materials to remove water particles. Pre and post filtration either side of your dryer is highly recommended to keep your dryer free of contaminants and to ensure the outgoing air is cleaned before entering your line.
It is recommended that all compressed air applications should have filtration. As your compressor pulls in atmospheric air, there are dust and other impurities that enter the compressed air system. Filtering out these impurities prolongs the life of equipment, tools and machinery.
Depending on your application, there are filters available to simply remove dust, to filters that make your compressed air cleaner than the air we breathe.
For workshops and non-critical applications, filters to remove moisture and impurities are relatively inexpensive and are readily available as off-the-shelf items and can be installed in-line to clean up the compressed air to suitable levels. These can range from around a 5 micron filter to 0.01 micron.
For food production, medical, critical electronic type environments and breathing air for spray painting, there are various classes and levels of filtration that may include absorption drying and activated carbon filters that clean compressed air down to extremely fine levels.
Critical air normally requires and utilises a water lubricated compressor that is totally oil-free, or an oilless compressor with no lubricant. For breathing air and most food production, oil flooded compressors are filled with food grade lubricant that is not harmful to ingest.
There are various different types of pipe used for air line installs, but currently the most popular option is Polyethylene. Polyethylene pipe comes in different grades, the preferred grade for compressed air is PE100. PE100 is a high grade pipe that has excellent strength and longevity characteristics and is resistant to corrosion. It has an exceptionally long life span of up to 200 years under pressure. PE100 has excellent thermal conductivity, seismic flexibility, is lightweight, simple to install and is highly resistant to impact damage due to its exceptional strength.
Other types of pipe are also for compressed air including stainless steel, galvanised steel, copper, aluminium and various others. Galv is not commonly used in compressed air installs nowadays due to its inherent corrosion tendency as well as being time consuming and difficult to install.
Air compressors should be situated in an area, taking into account the following:
- Under cover, out of the weather. Electric compressors shouldn’t be placed in an outside setting as it is dangerous for water to enter any of the electrical components. Either inside their own housing, or inside a building is the best place for your compressor.
- An area with good air flow. Compressors draw in many cubic meters of atmospheric air while in operation, therefore ensure you have sufficient ventilation to allow plenty of clean air to enter the compressor. Also, compressors can produce a lot of heat which needs to be expelled from around the compressor to ensure it won’t overheat. Heat can be one of the main causes of failures with compressor electrical components.
- Not too far from point of use. Compressed air drops in pressure over distance, so be mindful that you don’t add many metres of unnecessary pipework to feed the end user as you may experience a drop in pressure.
- Take into account the noise level of your compressor. Compressors can be quite high on the decibel meter, so keep this in mind and avoid placing the compressor in a place frequently occupied by workers. Piston compressors can be over 90 decibels, which can damage your hearing with prolonged exposure.
- Somewhere with a flat, sturdy floor. Your compressor must sit on flat, even ground to ensure the oil is sitting level and can be efficiently distributed throughout the machine, and so that condensate can be expelled through the lowest drain point. Compressors can also be very heavy, so be mindful that the floor below the compressor is rated to the correct load rating.
- Electrical power supply. Compressors are in most cases, the largest single consumers of energy in workshops and industry. Make sure you have a sufficient power supply to the compressor room and that the correct type of electrical fuses and breakers are installed. Electrical requirements vary depending on the size of the compressor, so ensure you have all necessary info for your electrician to install the correct power supply.
- Space and accessibility for servicing. Placing your compressor in a tight spot may be detrimental when it comes time for scheduled servicing. A technician should be able to move freely around the compressor and have space to work in comfortably, without any area of the compressor being out of reach.
Compressors run within a band of pressure e.g. most piston and fixed speed compressors run within about a 30-40 psi range. The pump will kick in when the pressure gets to it’s lowest point or ‘load’ pressure, and switch off at its highest point or ‘unload’ pressure. Variable speed screw compressors can be set to a specific pressure or ‘setpoint’ and will maintain that pressure within a programmed variance, usually around 1 bar.
The pressure you should run totally depends on what equipment or tools you are using. For instance, most pneumatic air tools are rated at a recommended pressure of 90 psi (6.3 bar) to 100 psi (6.8 bar). The majority of pneumatic equipment is fine to operate at up to 115 psi or around 8 bar, but some equipment requires higher or lower pressure.
Regulating pressure is a simple process and can be achieved by installing an in-line pneumatic pressure regulator to obtain the desired pressure. Check the pressure rating of your equipment to make sure your compressor complies with the rating, or call the Bayteck Systems team for advice.
