FEATURES

Choosing the right compressor?

Compressed air is the preferred choice of many to use in their workshop or on the work site. It is clean, simple to use and readily available. However, like most forms of energy it can be expensive, especially if the compressor you choose is too small or too large for your requirements. To select the most suitable compressor for your needs you will need to have answers to the following questions:

What will be your total air consumption?

You will need to know the total air consumption of the tool or tools you expect to be powering simultaneously.

What is the recommended air pressure your tools need to be operated at?

The operating pressure of air tools can vary from as little as 15 PSI to more than 200 PSI, working pressures are easily reduced using a regulator however, it is important to ensure your compressor can provide the higher end pressure you require.

Do you need your compressor to be portable or stationary?

How do you intend to run your tools?

Will you be running tools continuously, i.e., tools in constant use on a production line OR will the use be intermittent or short bursts such as it would be in the workshop or tyre shop?

Total air consumption requirement

For your air tools to work correctly your compressor needs to be able to supply them with enough air flow (l/min or CFM) at the correct pressure (PSI or BAR).

This information should be provided with the air tool instruction manual or be available from the tool manufacturer, it may also be noted on the tool itself.

For example, an impact wrench may have an air consumption of 350 l/min at a required pressure of 90 PSI.

The amount of air a compressor can provide is known as Free Air delivery or FAD. When choosing your compressor you need to ensure that the compressors FAD meets or exceeds the requirement of the tool or tools that will be connected to it.

For example, to run the impact wrench that requires 350 l/min, your compressor needs to be able to provide an FAD of at least 350 l/min.
However, if you were going to be running the impact wrench (350 l/min) at the same time as air saw (200 l/min), the FAD of the compressor would need to be 550 l/min (350 + 200).

Air pressure requirement

As well as FAD your compressor needs to be able to deliver the air at a high enough pressure to allow correct operation of the tool or tools.

SP Tools compressors are all 145 PSI (10 BAR) compressors, this will allow for most air tools with a higher PSI requirement to run using an SP Tools compressor. The use of a regulator will allow for you to reduce the supply pressure if a lower operating pressure is required (please note that running a tool above the recommended operating pressure can be dangerous and may lead to damage of the tool).

Portable or stationary use

Do you need to transport your compressor to the work site or will your compressor be a part of a stationary set up in a workshop?

With the exception of our stationary 3 Phase compressors, all other SP Tools compressors are considered portable.

If you need to be able to move your compressor around easily though you may be limited on size and you will also need to consider the availability of the power available on worksites i.e., the location of the power outlet and is it 10 or 15 Amp?

If electrical power is not going to be available you may want to consider a petrol powered compressor, remembering these should only be operated outdoors (never in an enclosed environment).

If using electricity to power your compressor, consider its location to the power outlet, it is always preferable to connect the compressor to the outlet without the need to use an extension lead. Extension leads can reduce the amount of power available to the motor causing it to overheat. Always opt to use longer air hose over an extension lead where possible.

Whenever using or locating your compressor, portable or stationary, ensure the area around it is large enough to allow adequate ventilation so that the compressor does not overheat.

How are the tools being run on your compressor being used?

It is important to consider the type and amount of use of the tools being used.

For example, is the work environment a workshop or tyre shop where the tools are being used intermittently or in short bursts, or are they a part of a production line where continuous FAD is required such as a paint shop or assembly line?

SP Tools compressors are Reciprocating Compressors, this type of compressor offers numerous advantages in efficiency and versatility and they generally cost less to purchase and maintain.

All SP Tools compressors have storage tanks which the compressor pump forces air into until it reaches its upper set pressure limit and the compressor shuts off. When the air in the tank is being used up by a tool the pressure inside the tank decreases to the lower pressure limit, at this point the compressor turns itself on to repressurise the tank (or continue to provide FAD until the tool is shut off and the tank can repressurise). Large amounts of heat can be produced when compressing air and this needs to be managed to prevent damage to the compressor. Once the compressor reaches the upper set pressure limit in the tank it shuts off the compressor giving it time to cool.

Reciprocating compressors have a 50% duty cycle, meaning that the unit requires roughly an equal amount of time to cool as it has taken to pressurise the storage tank. However, if the tool being used quickly consumes the air in the tank and the compressor must turn on more frequently to repressurise, the amount of time the compressor has to cool is greatly reduced.

If you are going to be using a tool or tools that have a higher air consumption, or you are going to be using tools in a continuous manner you will need to look at compressors with a higher FAD (greater than the consumption of the tool being used) and/or a larger capacity storage tank to prevent overheating and premature wear and tear on your compressor.

If your application requires a continuous FAD such as a paint shop, then you may need to consider a different type of compressor that is designed to provide a 100% duty cycle such as a Rotary Screw Compressor. These tend to be much more expensive to purchase and maintain and can, if not correctly sized to your application, greatly increase your energy costs.

Things to consider:

• Extra capacity, do you think you will require extra capacity in the future? If so, it would be worth considering this in your purchase.
• Location, try to locate your electric compressor close to the power source. Avoid using extension leads wherever possible, it is better practice to use a longer air hose. Check before your purchase whether you require a 10 Amp, 15 Amp single phase or 3 Phase power outlet.
• Ventilation, ensure there is adequate ventilation for your unit to cool. Avoid placing hard up against a wall, or under a low ceiling that prevents airflow via the cooling fins on the compressor pump and motor fan.
• Pressure regulation, to prevent damage to your tools regulate your pressure using either the regulator at the compressor outlet or via individual regulators at the air outlets in your workshop.