Sandblasting systems
Free jet sandblasting
The abrasive is introduced into the tank and, when the work cycle begins, it is dosed through the abrasive adjustment valve located in the lower part of the tank and mixed with the compressed air coming from the network.
The mixture thus composed runs along the abrasive tube and then comes out of the sandblasting nozzle where the abrasive undergoes an acceleration that launches it at very high speed against the substrate to be treated .
The output speed, working at a pressure of 7 bar, is around 80 metres / sec.
The free jet sandblasters produced by FEVI are powered by compressed air and are composed of:
- Tank to contain the abrasive subject to pressure
- Abrasive transport hose
- Sandblasting nozzle
- Control and safety systems
Tank to contain the abrasive subject to pressure
The sandblaster tank can be of different capacities and varies from 8 to 280 litres.
The container where the abrasive is placed determines the autonomy of work between one charge and another and is subject to the EUROPEAN PED 2014/68 / EU certification
Normally, the following devices are applied to it:
- Safety valve for the control of the maximum operating pressure
- Pressure gauge to check the working pressure
- Compressed air connection from the mains
- Air opening and closing valves for starting and stopping the work cycle
- Valve for adjusting the quantity of abrasive
- Connection for the abrasive transport hose
Abrasive transport hose
Hose made of special abrasion-resistant rubber, with a section between ½" and 1.¼", depending on the quantity of abrasive to be transported in the unit of time and its length which is normally between the 4 mt. and 40-60 mt.
In exceptional cases and for particular works, it is possible to extend the abrasive hose up to 100-150 metres.
This tube is normally connected at one end with a special quick coupling for attachment to the tank and at the other end with a nozzle holder where the nozzle is fixed.
Sandblasting nozzle
The sandblasting nozzle, built in hard metal particularly resistant to abrasion, is the component that determines the consumption of compressed air (between 100 and 8000 lt./min. at 7 bar) and is retained by the nozzle holder and moved by the operator who thus manages the direction of the jet.
There are different diameters normally between 1.5 and 12 mm., with cylindrical or Venturi hole with a length between 20 and 40 mm and with length between 70 and 150 mm.
Control and safety systems
The control and safety systems mainly consist of the remote control that allows the operator to start and stop the sandblaster.
This device is normally powered by compressed air or in special cases (for long distances) with low voltage electricity. The remote control is located near the nozzle to be operated only by the operator and is equipped with a padlockable safety lock system.
To obtain the elimination or abatement of dust generated by sandblasting work on pieces that cannot be inserted inside a booth or carried out in open spaces, there are two basic systems:
- Water sandblasting
- Recovery sandblasting
Water sandblasting
This technology essentially involves the use of water as a component or as a vehicle to bring the abrasive particles against the surface to be treated, thus eliminating the formation of the dust that develops during impact.
There are basically three types. If used on iron surfaces, these systems immediately determine the start of the oxidation process and it is therefore advisable to apply a passivating or phosphating product to the still wet surface to inhibit surface oxidation in the bud.
- Hydro-sandblasting
- Sandblasting with humidification kit
- Aero hydro-sandblasting
Hydro-sandblasting
As a base of hydro-sandblasting a pressure washer is used where, at the outlet of the water jet, a Venturi system is mounted which sucks the abrasive from a container. Basically, the air (transport vehicle of the abrasive in dry sandblasting) is replaced by water. This system achieves the elimination of dust, significantly penalising the following:
- yield per unit of time
- operation (the hose that sucks the sand cannot be longer than 4-5 metres and therefore it is necessary to continuously bring abrasive in the vicinity of the workplace)
- use of large quantities of water that drips copiously or accumulates on the treated surface.
The only advantage of the hydro sandblaster is the possibility to carry out the work without the need for compressed air.
Sandblasting with humidification kit
Sandblasting with humidification kit uses a dry sandblaster as a basis; the water is brought outside the jet of the air-abrasive mixture after the latter has come out of the nozzle. This system is very cheap, it maintains the yield of dry sandblasting, uses low quantities of water but the results of dust abatement are often not the best because normally the water taken directly from the water mains (in the presence of pipes even 20- 40 metres long which often run vertically) does not maintain the necessary flow to obtain the desired result. Furthermore, the water flow is not intercepted and suspended when the sandblaster stops.
Aero hydro-sandblasting
Aero hydro-sandblasting is the most recent and innovative technology; we can see its operating principle in detail in the illustration in the water sandblasting machine catalogue.
This system uses as a base a free jet sandblaster where water is injected into a chamber placed before the sandblasting nozzle. In this way, a homogeneous mixture composed of air-water-abrasive is obtained.
To perform aero hydro-blasting it is necessary to have a free jet sandblaster complete with the humidification kit which allows to obtain the performance of dry sandblasting with the dust abatement results of the hydro sandblaster. (The system is more expensive than the other two)
The water supply is independent of the mains pressure, thus always guaranteeing the necessary flow rate which is controlled by the starting and stopping system of the sandblaster.
Using dusty abrasives, it can happen that a part of these remains glued on the support; for this reason, it is possible to have a remote control placed on the handle, which allows the operator to shut off the abrasive flow. In this way, every 4-5 m, the operator can easily wash the already sandblasted part with a jet of air and water and then continue the sandblasting work by restoring the flow of abrasive through the remote-control device.
Recovery sandblasting
It is the most advanced technology and we can see its possible applications and systems in the Recovery Sandblasting Machines catalogue
This system uses as a base a dry sandblaster equipped with a special brush head that instantly recovers the dust and all the abrasive that is thrown during the work cycle. This system allows to obtain the best results in terms of environmental impact and safety yet it has the following drawbacks:
- high cost of the machine and low efficiency in terms of surface treated per unit of time with same nozzle
- operational difficulty due to the size of the handpiece moved by the operator and the limited length of the pipes which can reach a maximum of 24 metres.
However, it must be said that recovery sandblasting offers numerous advantages and more precisely:
- carry out retouching work on iron items or welding rods without damaging or affecting the adjacent parts
- polish, sandblast or clean stainless steel weld seams instead of using acids that are extremely problematic and costly to keep and dispose of
- perform the cleaning of details of stone, marble, granite, indoor stairways, without blocking the passage of people, empty the premises or protect furniture, furnishings and machinery
- considerable reduction in disposal as they are composed exclusively of the product removed from the sandblasted surface and of the crushed abrasive. These recovery machines select and recycle the abrasive used, discarding only the slag and the fine abrasive that can no longer be used.
- elimination of the abrasive collection operation
- possibility to automate the sandblasting or cleaning of cylinders, rollers or external tubes of any size. (For example) by applying the brush head on the tool holder of a lathe, we will automatically obtain a sandblasted surface immediately after machining.
- execution of inscriptions and decorations on marble, glass and wood surfaces, even on site, by shielding with special vinyl masks.
Dry ice sandblasting
Dry ice allows for residue-free cleaning, without water and chemicals: the application is environmentally friendly, bactericidal and significantly faster than conventional cleaning methods.
Dry ice cleaning is already used successfully in numerous industrial applications. Cleaning is much faster and easier than conventional methods and works without abrasives, without water and without chemicals.
The essential elements of the process are compressed air, generated by a common compressor, and dry ice in pellets
SUMMARY OF THE PROCESS
Freeze> Shatter> Remove> Sanitise
EFFECTS OF THE PROCESS
Mechanical / Thermal / Kinetic / Fungistatic / Sublimation
THE ADVANTAGES of cryogenic dry ice cleaning
- Dry process
This cleaning method is a completely dry process as dry ice is made up of CO2 and therefore evaporates upon contact with the surface. Cleaning without water and steam
- No residue
The process leaves no residue. It is only necessary to vacuum or collect the removed deposits.
- Ecological
Dry cleaning uses no chemicals and is absolutely non-toxic. There are no costs for the disposal of detergents or solvents and the quantity of debris to be purified decreases.
- Non abrasive
Dry ice cleaning has no abrasive effects and is therefore extremely delicate on the materials surface, avoiding the wear typical of sandblasting or cleaning systems with chemical agents, detergents, spatulas, and metal brushes.
- Increased productivity
Maintenance breaks are reduced as disassembly and reassembly operations are no longer necessary. Often the machines can be cleaned during operation, which increases the actual production time.
- Effective
Thanks to the jet nozzles and the different cleaning speeds, it is possible to clean even in places that are difficult to access without leaving any residue of detergent in the chains and on the mechanical parts.
- Safe
Cryogenic sandblasting performed with the use of personal protective equipment replaces traditional cleaning procedures such as sandblasting or cleaning with chlorinated or fluorinated solvents: it can therefore be said that cryogenic sandblasting introduces a significant improvement for the working conditions of the operator.
- Bactericidal action
Bactericidal and fungistatic cleaning
Booths
The sandblasting or shot peening booths are used in the industrial sector to clean, polish, satin finish and sandblast a very wide range of pieces in all types of materials (iron, glass, plastic, stainless steel, wood - etc.)
This sandblasting system is particularly suitable for artefacts with overall dimensions of less than 1500 x 1200 x h = 900 mm and with a weight not exceeding 300-500 kg.
For special cases it is possible to carry out modifications on the closing systems of the booths for particular pieces exceeding the size mentioned above such as eg. pipes, profiles or components that are much longer but have the other dimensions considerably smaller.
In these types of systems, abrasives or recoverable powders are always used, therefore, the advantage of this system, in addition to having the operator completely outside the sandblasting room, is the drastic reduction in waste disposal which is only what is removed from the treated surface together with the exhausted abrasive (whose quantity varies according to the type used).
This is possible because all these systems are equipped with more or less effective systems for the selection and cleaning of the abrasive.
The sandblasting or shot peening booths are divided into two large families according to the system used to launch the abrasive and more precisely:
Water sandblasting
This technology essentially involves the use of water as a component or as a vehicle to bring the abrasive particles against the surface to be treated, thus eliminating the formation of the dust that develops during impact.
There are basically three types. If used on iron surfaces, these systems immediately determine the start of the oxidation process and it is therefore advisable to apply a passivating or phosphating product to the still wet surface to inhibit surface oxidation in the bud.
- Hydro-sandblasting
- Sandblasting with humidification kit
- Aero hydro-sandblasting
Hydro-sandblasting
As a base of hydro-sandblasting a pressure washer is used where, at the outlet of the water jet, a Venturi system is mounted which sucks the abrasive from a container. Basically, the air (transport vehicle of the abrasive in dry sandblasting) is replaced by water. This system achieves the elimination of dust, significantly penalising the following:
- yield per unit of time
- operation (the hose that sucks the sand cannot be longer than 4-5 metres and therefore it is necessary to continuously bring abrasive in the vicinity of the workplace)
- use of large quantities of water that drips copiously or accumulates on the treated surface.
The only advantage of the hydro sandblaster is the possibility to carry out the work without the need for compressed air.
Sandblasting with humidification kit
Sandblasting with humidification kit uses a dry sandblaster as a basis; the water is brought outside the jet of the air-abrasive mixture after the latter has come out of the nozzle. This system is very cheap, it maintains the yield of dry sandblasting, uses low quantities of water but the results of dust abatement are often not the best because normally the water taken directly from the water mains (in the presence of pipes even 20- 40 metres long which often run vertically) does not maintain the necessary flow to obtain the desired result. Furthermore, the water flow is not intercepted and suspended when the sandblaster stops.
Aero hydro-sandblasting
Aero hydro-sandblasting is the most recent and innovative technology; we can see its operating principle in detail in the illustration in the water sandblasting machine catalogue.
This system uses as a base a free jet sandblaster where water is injected into a chamber placed before the sandblasting nozzle. In this way, a homogeneous mixture composed of air-water-abrasive is obtained.
To perform aero hydro-blasting it is necessary to have a free jet sandblaster complete with the humidification kit which allows to obtain the performance of dry sandblasting with the dust abatement results of the hydro sandblaster. (The system is more expensive than the other two)
The water supply is independent of the mains pressure, thus always guaranteeing the necessary flow rate which is controlled by the starting and stopping system of the sandblaster.
Using dusty abrasives, it can happen that a part of these remains glued on the support; for this reason, it is possible to have a remote control placed on the handle, which allows the operator to shut off the abrasive flow. In this way, every 4-5 m, the operator can easily wash the already sandblasted part with a jet of air and water and then continue the sandblasting work by restoring the flow of abrasive through the remote-control device.
Recovery sandblasting
It is the most advanced technology and we can see its possible applications and systems in the Recovery Sandblasting Machines catalogue
This system uses as a base a dry sandblaster equipped with a special brush head that instantly recovers the dust and all the abrasive that is thrown during the work cycle. This system allows to obtain the best results in terms of environmental impact and safety yet it has the following drawbacks:
- high cost of the machine and low efficiency in terms of surface treated per unit of time with same nozzle
- operational difficulty due to the size of the handpiece moved by the operator and the limited length of the pipes which can reach a maximum of 24 metres.
However, it must be said that recovery sandblasting offers numerous advantages and more precisely:
- carry out retouching work on iron items or welding rods without damaging or affecting the adjacent parts
- polish, sandblast or clean stainless steel weld seams instead of using acids that are extremely problematic and costly to keep and dispose of
- perform the cleaning of details of stone, marble, granite, indoor stairways, without blocking the passage of people, empty the premises or protect furniture, furnishings and machinery
- considerable reduction in disposal as they are composed exclusively of the product removed from the sandblasted surface and of the crushed abrasive. These recovery machines select and recycle the abrasive used, discarding only the slag and the fine abrasive that can no longer be used.
- elimination of the abrasive collection operation
- possibility to automate the sandblasting or cleaning of cylinders, rollers or external tubes of any size. (For example) by applying the brush head on the tool holder of a lathe, we will automatically obtain a sandblasted surface immediately after machining.
- execution of inscriptions and decorations on marble, glass and wood surfaces, even on site, by shielding with special vinyl masks.
Dry ice sandblasting
Dry ice allows for residue-free cleaning, without water and chemicals: the application is environmentally friendly, bactericidal and significantly faster than conventional cleaning methods.
Dry ice cleaning is already used successfully in numerous industrial applications. Cleaning is much faster and easier than conventional methods and works without abrasives, without water and without chemicals.
The essential elements of the process are compressed air, generated by a common compressor, and dry ice in pellets
SUMMARY OF THE PROCESS
Freeze> Shatter> Remove> Sanitise
EFFECTS OF THE PROCESS
Mechanical / Thermal / Kinetic / Fungistatic / Sublimation
THE ADVANTAGES of cryogenic dry ice cleaning
- Dry process
This cleaning method is a completely dry process as dry ice is made up of CO2 and therefore evaporates upon contact with the surface. Cleaning without water and steam
- No residue
The process leaves no residue. It is only necessary to vacuum or collect the removed deposits.
- Ecological
Dry cleaning uses no chemicals and is absolutely non-toxic. There are no costs for the disposal of detergents or solvents and the quantity of debris to be purified decreases.
- Non abrasive
Dry ice cleaning has no abrasive effects and is therefore extremely delicate on the materials surface, avoiding the wear typical of sandblasting or cleaning systems with chemical agents, detergents, spatulas, and metal brushes.
- Increased productivity
Maintenance breaks are reduced as disassembly and reassembly operations are no longer necessary. Often the machines can be cleaned during operation, which increases the actual production time.
- Effective
Thanks to the jet nozzles and the different cleaning speeds, it is possible to clean even in places that are difficult to access without leaving any residue of detergent in the chains and on the mechanical parts.
- Safe
Cryogenic sandblasting performed with the use of personal protective equipment replaces traditional cleaning procedures such as sandblasting or cleaning with chlorinated or fluorinated solvents: it can therefore be said that cryogenic sandblasting introduces a significant improvement for the working conditions of the operator.
- Bactericidal action
Bactericidal and fungistatic cleaning
Booths
The sandblasting or shot peening booths are used in the industrial sector to clean, polish, satin finish and sandblast a very wide range of pieces in all types of materials (iron, glass, plastic, stainless steel, wood - etc.)
This sandblasting system is particularly suitable for artefacts with overall dimensions of less than 1500 x 1200 x h = 900 mm and with a weight not exceeding 300-500 kg.
For special cases it is possible to carry out modifications on the closing systems of the booths for particular pieces exceeding the size mentioned above such as eg. pipes, profiles or components that are much longer but have the other dimensions considerably smaller.
In these types of systems, abrasives or recoverable powders are always used, therefore, the advantage of this system, in addition to having the operator completely outside the sandblasting room, is the drastic reduction in waste disposal which is only what is removed from the treated surface together with the exhausted abrasive (whose quantity varies according to the type used).
This is possible because all these systems are equipped with more or less effective systems for the selection and cleaning of the abrasive.
The sandblasting or shot peening booths are divided into two large families according to the system used to launch the abrasive and more precisely:
Suction / depression booths or shot blasting machines
The cabins with suction or depression system have been the most widespread and well-known on the market for over 40 years.
In the face of a simplicity of operation and a much lower cost than the advanced pressure system, they are much less effective for the aspects described below:
- lower yield per unit of time, with the same compressed air consumption
- limited possibility to adjust the range of the working pressure
- limitation in the use of types of abrasives (the suction system does not allow the use of metal grit)
- lack of possibility to adjust the quantity of abrasive in the air-abrasive mixture.
- less ventilation inside the cabin, less sophisticated abrasive selection and cleaning system, less effective and without the possibility of calibration.
Any booth or shot-peening machine existing on the market operating with a suction system, can be modified and transformed into a booth operating with a pressure system by means of a very easy-to-apply kit, supplied by FEVI, together with the manual and drawings to make the necessary changes.
Cabins with pressure system
The booths with pressure system are the innovation resulting from the need to reduce production costs, increasing the performance of the machines in the unit of time. It is very simple, in fact, to demonstrate to a potential customer through a practical test that the greater investment they will make with the purchase of a booth equipped with a pressure processing system, will be amortized within a few hundred hours of work for the following reasons:
- increase in yield of 2 or 3 times with the same compressed air consumption
- possibility to increase the yields to 4-5 times if you have more compressed air available
- possibility (if convenient) to also use abrasive of the metal grit type with the advantage of less wear of the system components (pipes, nozzles, valves), less wear of the abrasive itself and better cleaning and separation of the slag.
- improvement of ventilation inside the cabin and the possibility to carry out adjustments to the dust waist and therefore to the discarded abrasive.
- possibility to adjust the quantity of abrasive in the air-abrasive mixture and the working pressure with much wider parameters.
The same recovery and selection system can be applied to small cabins designed for operator access, with dimensions of 2 or 3 metres x 3 –4 m. x H = 2-2.5 m.
