screw, piston, diesel or electric
With the growth of the level of technical solutions, even in a small workshop, it is possible to organize a workplace for sandblasting a variety of materials. This became possible both due to the appearance of affordable compressors on the market, and the availability of a variety of components and consumables, such as nozzles, oil and moisture traps, and abrasive powders.
However, to achieve high productivity and efficiency, you need to choose the right equipment. The compressor for the sandblaster must have certain characteristics depending on the surface to be treated. There are also a number of recommendations for the construction of strapping and other parts of the overall technical solution of the tool kit. Before reading the article, we recommend that you look at the various options for sandblasting compressors.
Selection of the main characteristics of the compressor
In a variety of reference materials, you can find data that the minimum compressor performance threshold should be 500 liters per minute at a pressure of 5 bar. However, almost nowhere is the truth told. You can even choose a compressor for sandblasting with such characteristics without the necessary binding. However, while doing so:
- the sandblaster will only be able to work with limited types of surfaces and coatings;
- long-term use of the sandblasting unit is not ensured — pauses are needed to cool the engine;
- the sandblasting compressor will show all its design features, in particular, rotary models will inevitably supply air in jerks.
Based on practical experience of use and recommendations from leading manufacturers of professional equipment, an honest assessment of the minimum requirements for the injection complex can be made. The compressor must necessarily work with a piping in the form of a receiver. With the correct choice of its volume, it is possible to achieve the required continuity of operation, even if a piston-type supercharger is used.
The main requirements by which you can choose a compressor for a sandblaster depend on the materials and nature of the coatings that you have to work with:
- for processing concrete, chamber surfaces, wall brickwork, the minimum level of working pressure should be 3 bar;
- when working with metal, the compressor must provide a pressure of 6 bar;
- for removing tough coatings, the recommended pressure is 9 bar.
The maximum that you should focus on if you want to choose a compressor for sandblasting with high versatility is pressure at 12 bar. In the recommendations under consideration, it is assumed that the diameter of the working nozzle is 5 mm, and the pumping rate is 800 liters per minute.
Advice! Today, many manufacturers offer ready-made air stations for sandblasting, providing performance levels from 700 to 1000 liters per minute with a pressure of up to 12 bar. It is this kit that is recommended to purchase for optimal performance and ease of use in the workshop. For industrial purposes, it is recommended to choose a device with a capacity of 3000-5000 l / min and an outlet pressure of up to 10 bar. Usually these are screw type compressors.\
The right choice of hoses
An important role in the formation of the final parameters of the air-abrasive jet of sandblasting is played by the equipment of the apparatus. These are hoses, various connecting elements, spurs, adapters. In order to use the compressor power optimally, we recommend:
- prevent changes in the diameter of the air passage channel along the route;
- minimize the number of transition elements;
- use strong, non-kinking hoses with a diameter that is 3-4 times the working diameter of the nozzle.
The length of the hose from the air station to the sandblasting gun should be as short as possible. A mobile industrial compressor necessarily takes into account this feature. If it’s about semi-handicraft installationit is recommended to increase the length of the hoses by extending the hose from the compressor to the abrasive-air mixing unit.
You can further increase productivity, reduce downtime, and achieve the right, consistent pressure for sandblasting by choosing the type of blower.
Compressor type selection
The main requirement when supplying compressed air to the mixing chamber of a sandblaster is uniformity. Therefore, some types of compressors clearly win the comparison due to their design features. Others are more common and more affordable. What exactly to choose depends on the planned volumes and the nature of the work performed.
Reciprocating compressors look like an ideal option for users who need to do small to medium jobs.. They will fit well in the garage, quite unpretentious in winter. However, this type of device has some peculiarities.
- Due to the discrete operation of the piston group, air enters in jerks.
- Apparatus suitable for sandblasting will be oil type. In such devices, oil droplets cannot be excluded from entering the outlet air stream.
- The compressor must be operated with obligatory stops for cooling.
Important! A piston model without strapping is not very suitable for a sandblasting machine. Air rushes can cause unwanted damage to the surface. Oil ingress can cause abrasive clumping, blockage or failure of the mixing unit, and unacceptable surface finish.
However, a piston compressor is better to buy as part of a finished air station. In this case, the device will be equipped with the necessary harness, which includes:
- a receiver in the role of a shock-damping accumulator that removes feed surges and allows the engine to stop for cooling;
- oil trap installed at the compressor outlet;
- reducer stabilizing the output pressure;
- condensate (moisture) trap installed at the outlet of the station or included in the pressure reducer.
A properly equipped station is perfect for small workshops. With the right choice of parameters, it will provide the necessary pressure for sandblasting and pumping volume, while not overheating to stop for a long time.
The main feature of the screw compressor, valuable for sandblasting machines, is the complete no air blows at the outlet. Devices of this class:
- practically do not vibrate during operation;
- precisely adjusted at the factory and do not require intervention, complex periodic maintenance;
- characterized by very stable operation.
However, screw compressors are not a frequent inhabitant of small workshops. The reason is simple: road devices, often focused on a stationary installation. The screw compressor generates significant pressure and is characterized by a huge air capacity. Equipment of this type is rational to use paired with a receiver (or several) to power multiple sandblasting machines.
Electric compressors are the most common class of equipment. Among the models offered on the market, you can choose the product of the desired power and performance. However, if we talk about the large-scale use of such devices, it becomes clear that with some boundary requirements for the volumes and parameters of the supplied compressed air, the use of such compressors economically inefficient. Therefore, the places where the electric air compressor is used are limited to small, medium-sized workshops, private garages.
Important! Equipment of this class has another drawback: it requires a powerful source of energy to work. Therefore, the electric compressor is used, so to speak, within the boundaries of civilization, where there are centralized energy supply networks.
Diesel and petrol
Diesel and petrol compressors offer huge benefits in many applications. For example:
- work without a power supply;
- can operate in frost (diesel engines — provided they are equipped with a special starting system, the so-called winter package);
- in some cases — more economical than electric ones.
But most importantly, what is valuable about a diesel or gasoline compressor is that their energy content is much higher than electrical devices. With the same mass indicators, equipment on an internal combustion engine will be much more powerful and productive.. Therefore, often large workshops or production shops use diesel or gasoline compressors.
Important! As another important feature of equipment with an internal combustion engine, one can note the best cooling mechanics and the possibility of continuous operation over several shifts or around the clock. Therefore, diesel and gasoline compressors are quite popular, they are offered in a huge range of models, screw and piston types.
Should I buy a used compressor?
The secondary market for equipment is very attractive with low prices, blooms with assurances of sellers in the style of “turned on once to check”, pleases with a variety of compressors for sandblasting. However, considering used equipment, you should not succumb to external impressions. Many products of the secondary market undergo cosmetics, pre-sale preparation. They look great, but this does not affect the nature of the work. If the difficult financial situation makes you pay attention to used compressors, it is worth remembering some facts.
- Over time, the compressor parameter inevitably drops.. Therefore, if you need to buy equipment with high performance, it is better to check it carefully using flow meters and other measuring devices.
- Diesel compressors are the most worn. The piston group of the engine is destroyed due to the constantly high pressure in the chambers. The engine consumes more fuel with less power output, has difficulty starting with a drop in air temperature. Used equipment of this type will require high maintenance costs, constant cleaning, repairs.
- Aftermarket Screw Compressor — a real dark horse. Equipment may not meet specifications. In addition, worn bearings or rotor blocks will require expensive repair or replacement, with the involvement of specialists or company service. Even worse, if the shutdown of the compressor will cause a stoppage of work and disruption of the deadlines for the implementation of orders.
- Equipment with uncommon types of units, lubricants is not the best choice. This is especially true for products of Chinese industry and unknown brands. In case of failure, it can be very difficult or impossible to repair such a compressor due to the unavailability of spare parts.
Manufacturers of sandblasting compressors (if we are talking about serious companies) always declare the duration of normal operation for their equipment. Usually this period is 7-10 years. According to this parameter (based on the date of sale or release), you can choose a compressor in the secondary market.
Advice! It is impossible to focus only on the nominal service life when assessing the rationality of the purchase. The compressor could operate in critical modes, overheat, use poor quality fuel, operate with undesirable power parameters. Therefore, each device must be checked as carefully as possible, paying attention to the wear of moving parts, air flow parameters, the condition of the windings and other key details.
How best to operate the compressor
When working with a sandblaster, it is necessary not only to achieve high labor productivity and the required surface finish. The operator always faces the following list of tasks.
- Achieve as many recovery cycles for the abrasive as possible.
- Avoid undesirable effects on the treated substrate.
- Work in any weather.
- Reduce the ingress of dust into the inlet tract.
To solve the listed tasks will allow industrially produced nodes, some of which must necessarily be included in the air station piping.
Condensation always occurs at the boundary of pressure transformation. When air is taken in and compressed in the supercharger, condensate is necessarily formed, which enters the outlet tract. Air droplet entry:
- causes clumping of abrasive sand, which reduces the quality of processing, can disrupt the operation of the mixing unit;
- causes corrosion of some abrasive materials, in particular steel shot, which reduces the number of recovery cycles and economic efficiency.
Condensate can be neutralized using a compressed gas cooler, after which a cyclone separator-moisture trap is installed.. This set of equipment is installed at the outlet of a supercharger (recommended) or a receiver.
The presence of oil in the outlet air stream is a common feature piston devices. The mechanics of the action of such impurities on the abrasive mixture is similar to the effect of condensate. Except that the oil is non-corrosive. However, it can be highly undesirable in surface treatment.
Getting on the base, the oil can cause a variety of unpleasant consequences: from a violation of the chemical composition, a decrease in adhesion, to destruction or discoloration. To neutralize such an impurity in the outlet air flow, special trap. This assembly must be installed directly at the compressor outlet.
Temperature drop below 0% is dangerous for electrical devices. A further decrease in performance may cause problems starting internal combustion engines. It is especially difficult to start a diesel engine in cold weather. Therefore, if you plan to work outdoors in winter, you should definitely take measures to ensure proper operating conditions for the compressor.
Electrical devices are heated body. Such a system can be made independently using temperature sensors and a special heating cable.
Advice! For compressors with an internal combustion engine, it is recommended not to create inefficient and often dangerous homemade products. Compressors of this class must be purchased with complete winter packages.
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Reducing the amount of dust in the inlet tract
The easiest way to eliminate the risk of dust entering the compressor. Schemas are used for this.
- to the compressor station supercharger and receiver combined into a single structure, an underwater hose is attached, the end of which is led far beyond the working area.
- In systems where compressor and receiver separated, it is allowed to lengthen the route coming from the supercharger. The latter is placed away from the work area. Extending the hose from the receiver to the sandblast gun is not recommended.
In some cases, to clean the inlet air from dust, you can use automotive or special industrial filter. Such equipment will require periodic cleaning of the assembly or replacement of the working element. However, in cases where it is not possible to clean the inlet air in another way, it is quite rational to go for such expenses.
The right compressor is the key to high-quality surface treatment with good labor productivity. However, without proper piping, means of cleaning the air from moisture, oil, it simply will not work to achieve the required continuity and convenience. Therefore, the issue of choosing equipment must be approached with full attention, not trying to save on key elements or by buying used units.
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