When choosing an air compressor you may not know where to turn if you don't know exactly what to look for. The reason is that these compressors operate different types of tools, as well as cover a wide range of uses. To get the right air supply for your needs, you'll need to arm yourself with the right knowledge. Here's how to get to know and distinguish the various types of compressors.
Steps
Part 1 of 2: Knowing the Basics
Step 1. Analyze the needs of the air appliances you intend to use
Will you use the compressor on an industrial level, therefore to power heavy machinery, or will you limit its use in the home, for example to operate a silicone gun or inflate tires? If you plan on industrial use, you will probably need a piston compressor with a reservoir; otherwise, a portable one without a tank will suffice.
- Consider in particular the volume and pressure requirements of each instrument you are going to use. Obviously heavy machinery requires a lot more pressure and, consequently, more volume. If the compressor you have chosen is too small in relation to the use you had planned, you will find yourself periodically waiting for the tank to fill up, thus decreasing the working efficiency.
- If, for example, you need a portable air compressor for airbrushing, a 5 liter tank and a constant pressure of around 30 psi are sufficient.
Step 2. Choose between piston and portable compressors
Essentially, there are two different types of air compressors. Those with pistons work thanks to an engine that accumulates the air pressure once it is exhausted (in practice the compressed air is stored in the tank). Portable compressors, on the other hand, do not have tanks, and to supply the air they have to be constantly running.
- There are two types of piston compressors. Single-stage compressors use a single piston to compress the air and reach a pressure corresponding to approximately 150 psi. Two-stage compressors, on the other hand, use two pistons to deliver a constant flow of air, and are around 200 psi.
- Single-stage compressors are suitable for consistent use but still in a home context. The two-stage ones are most often used in industrial plants, where continuous use is required.
- Portable air compressors are useful in the home: operating silicone guns, airbrushes, glue guns, as well as inflating tires and small inflatable boats.
Part 2 of 2: Making Specific Decisions
Step 1. Check the compressor power
A common power range is between 1.5 hp and 6.5 hp. There are also larger capacity compressors, but they are usually reserved for industrial use and offer a much higher output. Small-scale uses do not require as much power as is needed for industrial machinery.
Although power is an important factor in choosing a compressor, it is not the only parameter to consider. Even more important is the value corresponding to cubic meters per second (mc / s). Read on for a detailed explanation about this parameter
Step 2. Find the value corresponding to cubic meters per second, or mc / s
Mc / s is the unit of measurement of the volumetric flow rate. Simple enough, isn't it? The difficult part is that this value changes according to the air pressure delivered, consequently the volumetric flow rate of two instruments having different psi will not be intuitively estimated. Here's where things start to get complicated. Let's try to make them easier:
- When evaluating some compressors, ask about the standard cubic meters per second (SMC). SMC is measured at a pressure of 14.5 psi, at a temperature of 20 ° C and with relative humidity of 0% - if you choose not to use the standard cubic meter method, be sure to use mc / s values with an identical psi value.
- When you have found the SMC of all the instruments you will be using simultaneously, add them together and then increase the value found by 30% in order to keep a safety margin. This should give you the maximum SMC requirement needed to complete the job. When choosing an air compressor, you will need to try to get close to this number so that you don't waste time with a unit that is too small or waste money on one that is too large.
- Let's say, for example, you want to use a grease gun (about 4 mc / s at 90 psi), a pneumatic nailer (about 2 mc / s at 90 psi) and a double sander (about 11 mc / s at 90 psi) more or less at the same time. Adding up all the SMCs you will get 17 SMCs at 90 psi, which is the maximum power required.
Step 3. Take space and portability into account
For example, will you be able to rotate the compressor or lift it off the ground if necessary? Compressors can be small and portable, or they can be bulky and powerful equipment. Portability is beneficial, but if you know the compressor will stay in a corner of the garage you may want to sacrifice it in favor of a higher capacity, and simply use a longer hose. Ultimately, will the compressor you're looking for need to power a pneumatic nailer to use on the roof or just inflate the tires in the garage?
Step 4. Also consider the energy source
Do you have the possibility of always having electricity, or will you find yourself in environments that may be without it? If you will always be able to find a power outlet, it is best to choose a compressor equipped with a transmission system with an electric motor. Otherwise, you will have to orient yourself towards one equipped with a petrol engine.
Most air compressors run at 110/220 v, but the larger ones also run at 240 V. Find out before purchasing
Step 5. If you are using a piston compressor, determine how large the tank should be
If you plan to use the compressor for short periods of time - for example to load a nailer - a small tank is sufficient. If, on the other hand, you will use it for longer periods, it will necessarily have to be larger. Tank size is usually measured in liters.
Advice
- Aim for a slightly higher product than what you thought you were getting.
- Oil-lubricated compressors tend to last longer than oil-free ones, and are quieter.
- Collect useful information about the required needs, then look for a product that meets them.
- Don't forget the length of the tube. What is the position of the compressor in relation to the work area? If the compressor is in the garage and work is on the road, act accordingly.
- Pancake-shaped compressors have high pressure, but low volume. Unless you need maximum portability, a container compressor may have better volume.
- Oil-free compressors may look great in the store, but they will be quite noisy in your garage, so be aware of this before you buy them. However, they deliver purer air than oil-lubricated ones.
Warnings
- Air-powered machinery can be dangerous. Read the user manuals carefully and use them with care.
- Avoid placing air compressors in places where they could fall.
