Air Compressors WA has a large range of Piston Air Compressors (sometimes called Reciprocating Air Compressors), whether you’re looking for Oil-Free Air Compressors, Silent Air Compressors, Lubricated Air Compressors or Piston Compressors with Cast Iron Pumps for example.
Which one suits your needs? Read on to learn more about the different types to guide you in next purchase.
How do piston compressors actually work?
The pump on a reciprocating piston air compressor is somewhat similar to an engine, where you have a piston in a cylinder that is attached to a crank. The crank pulley on an air compressor is spun by an electrical motor, when the crank spins the piston travels up and down the cylinder. On the downward stroke, a vacuum is created inside the cylinder and the intake valve is opened, allowing atmospheric air to enter the chamber. The piston then travels back up the cylinder, and the lack of vacuum at this stage shuts the intake valve and once the piston reaches the top and it is high pressure, the exhaust valve opens to push the compressed air into the air receiver (tank).
Generally there is a fan attached to or built into the pulley on the pump which provides cooling assistance. The process of compressing air creates heat, and this heat needs to be disappated. The fan only cools so much, and thus piston machines have a duty cycle that needs to be adhered to to reduce wear on the machine (to let it cool down).
Lubricated, oil-free, silent – what does it all really mean?
Traditionally, piston air compressors are lubricated. This means the crank of the pump sits in air compressor oil and as it rotates the oil is splashed around inside the core of the pump and it keeps everything lubricated. The oil does not enter the cylinder where air is drawn into it and compressed. The simple design of these machines that they generally last a long time and their only maintenance is to change oil annually, and perform a check on the components.
Oil-free air compressors follow the same general concept of creating compressed air, except for that instead of lubrication help the metal components not wear, they use teflon on the pistons. The teflon rings/seals on the pistons ensures the piston can travel up and down the cylinder without scoring. Annually the head of oil-free compressors should be removed to inspect for wear. The teflon rings may need to be replaced if they are showing signs of wear. Never wait until you can hear the compressor making odd sounds, as it may already be too late, with scored bores or worse, needing a full pump replacement.
Silent air compressors claim to produce around 10db less than tradtional air compressors of the same size and air flow capacity. This lower decimal rating e.g. 65db instead of 75db is not inaccurate, but the units are far from silent. The tone of the units changes to a higher pitched tone than that of a traditional deeper tone of a lubricated air compressor, and it’s really up to the individual person as to if they prefer that.
What about oil in the air?
It’s a good question, and the reality is that an oil-free air compressor does have less chance of having the air contaminated with oil. However lubricated air compressors are designed to not let the oil go near the compressed air, and so as long as the unit is operating correctly it would not be an issue. Every air compressor realistically requires filtration, and any contaminants would be removed before the air is used.
Pump types – double/triple headed, aluminium or cast iron?
Aluminium heads are cheaper to produce and result in a cheaper air compressor, but ultimately the cost of that is longetivity. If today’s budget is your number one priority, then the major hardware stores sell units that will get you going today. If quality, longetivity and not needing to even think about your workshop compressor are important to you, then you will be wanting to have a cast iron pump. The cast iron pumps are more resilient, can handle higher temperatures better and in general will simply work harder and last longer than aluminium heads. The entire Akko range and the Chicago Pneumatic Ironman range have cast iron heads.
How many heads on the pump? Well it doesn’t really matter, as long as you get the flow and pressure you need from the unit. More or less heads doesn’t necessarily mean its better.
Power – three phase, single phase, 20amp, 15amp, 10amp and extension cords
Some small units will run on basic household or workshop 240v power with a 10amp plug, much like a kitchen kettle, but as more air flow is required then the power consumption also increases.
240v also is available in 15amp. This is identified by a larger earth pin.
Three phase plugs are 20amp which is up to around 11kw (15hp) or 32amp which is 15kw (20hp). Anything larger needs to be hard-wired into the power circuit.
