Important features
- Powerful
- Air flow
- Pressure
- Tank volume
Compressor for occasional use
Inflate a swimming pool or a balloon, a bicycle wheel, check the pressure of your car tires, use a low-pressure paint gun to paint small areas, use a blower … if you are looking for a small compressor to help you out in these occasional tasks which require little pressure and air flow, a portable compressor is perfect.
Operating without oil, light and portable and most often deliver with a set of inflation tips, we like its attractive price and the services it provides. 1.5 horsepower (hp) for 8 bars (B) cover the needs. In the event of prolong use, take breaks because their low capacity tank (6 liters, 8 l etc.) means that their motor is often trigger. The mini compressors without tank themselves operate continuously and are for even more occasional needs.
Compressor for home use & small DIY
Inflation, stapling, nailing, cleaning the blower, small painting, gluing, pressure car tires … to work longer durations but still household , you can refer you to a single cylinder compressor.
Prefer a volume of 50 liters for a quick recharge, a certain autonomy and a moderate triggering of the engine. Wheels are essential for its movement to be practical. A flow of about 15 m 3 / h with a power of 1.5 hp will be sufficient. The compressor kits offer pneumatic tools with a working pressure suitable for household compressors tanks – 8 mini bars are often request.
Compressor for regular use
Inflating, stapling, cleaning with a blower, painting, gluing, drilling, chiseling… for DIY enthusiasts who regularly use their compressor, it is imperative to have a substantial reserve of air and a correct airflow. A tank of 100 to 150 liters and a flow rate of 15 to 25 m 3 / h will be perfect.
The power of the compression group will range from 2 to 3 hp. If you work in a workshop or if you supply a pneumatic network, prefer a fix compressor. If you are tinkering in various places or outdoors consider a compressor with wheels, preferably inflatable for greater maneuverability.
Compressor for professional use
All basic work as well as the use of pneumatic tools such as impact wrench, sandblaster, sander, grinder … For intensive use with large air needs, a tank of at least 200 liters with a flow rate of at least less than 40 m3 / h is ideal.
In a professional workshop, a three-phase 400 V compressor is a good choice. If you need mobility, then it will be necessary to move towards a compressor-type “trailer” equip with a heat engine.
4 points to remember to make the right choice
- Continuously operating tools require a larger volume tank to avoid continuous motor triggering which generates noise pollution and premature compressor aging (the main tools: pneumatic sander, pneumatic gun (for painting large surfaces), sandblaster, chipper, etc.).
- The airflow (l / min) and the pressure (bars) are to be chosen according to the tools you are going to use (cumulate the flow rates of the tools if using several at the same time). Multiply this flow rate by 1.5 for comfortable use and add 2 or 3 B as need.
- The power is relative to the airflow and the volume of the tank; it is not in itself a key characteristic.
- Oil-free motors are popular because they are maintenance-free and are suitable for occasional use
Three types of compressors are different:
- portable compressors,;
- single-cylinder compressors, either single-piston;
- twin-cylinder or multi-cylinder – stage compressors.
Portable compressors
If you just want to inflate tires, blow clean, or glue and staple, look to the family of portable oil-free compressors. Small and light, portable compressors are ideal for odd jobs. The majority of portable compressors have a tankless than 20 liters, maximum power of 1.5 hp, and airflow of about 8 m3 / h for the most efficient.
For occasional jobs, outdoors, or in tight spaces, portable compressors are perfect. Several brands offer portable compressors operating either in 230 V, or, for nomadic use and on battery in 12 V with a cigarette lighter type socket. Some portable compressors are even tubeless and weigh less than 4 kg!
Single-cylinder compressors
Single-cylinder compressors are the most representative compressors. Suitable for larger jobs or for longer periods of time, the compression unit is made up of an engine that operates a single cylinder.
The power of single-cylinder compressors varies from 1.5 hp to 6.5 hp and the volume of their tank is from 25 to 250 liters. Single-cylinder (single piston) compressors are capable of delivering up to 40 m3 / h at a pressure of around 8 bar. The tank is either fix on a frame itself mount on an axle to be able to move the compressor easily and effortlessly or on wall support for supplying a pneumatic network.
Twin-cylinder compressors
Two-cylinder, stage or multi-cylinder compressors are fit to the largest installations. Often intend for professionals and workshops , this type of large capacity, high power compressor is suitable for supplying a compress air network. The compression unit is made up of an engine that drives several cylinders.
Capable of delivering an air flow greater than 40 m3 / h at a pressure that can rise up to 13 bars , the twin-cylinder compressor is ideal in bodywork , painting, mechanical workshops , or even for experience DIY enthusiasts, using lots of pneumatic tools and having a workshop.
The operating principle of an air compressor is relatively simple: an electric or thermal motor drives a cylinder that compresses air in a seal tank of varying capacity, at a certain pressure . Once this pressure is reach, the engine stops. The engine + cylinder (s) assembly is call the compression group . This compress air can then be use to actuate one or more tools simultaneously:
- blowgun ;
- paint gun ;
- pneumatic nailer etc.
The most important characteristic of a compressor is the air flow it delivers. The air flow is measure in l / min (liters per minute) or in m3 / h (cubic meters per hour) . 1 m3 / h = 16.67 l / min . This air flow will depend on the volume of the compressor tank, as well as the speed at which the compression unit is able to fill it.
It is important to emphasize that some compressors do not have a tank (in the portable compressor range). The engine therefore runs constantly to deliver pressurize air. To choose the right air compressor , it is essential to best estimate the air flow that you will need.
Formula for calculating the air requirement
To assess your air needs and choose your compressor, there is a simple and effective formula: air consumption (in l / min or m 3 / h) of all your pneumatic tools x 1.5.
By referring to the technical documentation of your pneumatic tools or those you plan to purchase, you will easily obtain this information, and thus you can determine the airflow you need.
The power of the compressor unit and the volume of the tank generally correlate with the desire airflow .
Regulation and security
A compressor has various safety devices that are essential for the proper functioning of the group:
- The pressure switch works like a switch. As soon as the pressure drops below a certain threshold, it restarts the engine. Present on all recent compressors, the pressure switch threshold is generally factory-set at 4 bars.
- The pressure regulator is in fact a kind of valve which makes it possible to regulate the pressure to be reach, and / or the pressure at the compressor outlet. The pressure regulator is use to protect the connect accessories and not the user (not to be confuse with the pressure switch).
- The manometer is a visual needle or digital indicator of the pressure in the tank, and / or at the compressor outlet. The manometer is useful for checking its settings.
- The safety valve is useful in the event of a malfunction of the regulator or the pressure switch, so as not to over-inflate and cause the tank to explode, the valve opens to release the air and prevent any accident.
- The direct outlet is an auxiliary air intake that is not connect to the regulator. We, therefore, have on this outlet the maximum pressure of the compressor (generally around 8 bars).
Types of compression groups
Oil-free group
This is the type of group that equips small compressors intend for occasional use or for short periods .
The maintenance is reduce but the lifespan too! This type of compressor is often noisy.
Cast iron group
Conversely, it is the type of group which generally equips large compressors under heavy strain.
The cast iron induces an optimal heat exchange, the cooling of the unit is better, the service life is extend.
Aluminum group
The most widely represent, this type of group equips most compressors and is suitable for most DIY enthusiasts.
Not recommend, however, for intensive or professional use, the cooling is poorer and slower than on a cast iron unit and consequently, the compressor life is shorter.
Air filter
In order not to damage the compression group, the compressors are equip with an air filter.
For more professional models, there are also filters at the tank outlet to work with clean, dry air .
Carry out the interview
To extend the life of your compressor, it is necessary to carry out maintenance operations.
- Regularly clean the air filter: the air surrounding the compressor is suck in to be compress. Dust-laden air, for example, can damage your pneumatic tools. It is therefore important that the compressor air filter is clean for its maximum efficiency!
- Bleed the tank: compressing moist air creates condensation inside the tank. To prevent this water from eating away at the metal, where it does not freeze, each compressor is fit with a bleed screw (locate under the tank). Bleed regularly, especially before a prolong period of inactivity. Obviously, the problem does not arise for portable compressors without tank!
- Changing and oil level: check the oil level regularly , and change it at least once a year.
To avoid any accident, it is strongly recommend that you be well inform about the operating pressures of your various tools. In addition, some compressors are subject to special regulations which require periodic control and inspection every 40 months. Many accidents occur because of rusting tanks or faulty pressure switches/pressure regulators … Think about your safety!
Tools and accessories
For small tools such as blowgun, inflator, airbrush, prefer an air supply hose with an internal diameter of 6 to 8mm, for larger tools choose a hose with an internal diameter of 10 to 12mm. ” to avoid any loss of efficiency of your pneumatic tools make sure to maintain the inside diameter of the outlet of the pressure regulator (where the air exits) from the compressor, up to the connection nipple of the tool.