Working principle and application of shot blasting cleaning machine

Shot blasting is a kind of shot blasting surface treatment method which has been applied in developed countries in Europe and America. The world's first shot blasting equipment was born 100 years ago. It has been applied to remove impurities and oxide scale on various metal or non-metal surfaces and increase roughness. After a hundred years of development, shot blasting process and equipment have been quite mature, and its application is not only in various heavy industry factories. With the birth of the world's first horizontal mobile shot blasting equipment in blastrac, its application field has rapidly expanded to concrete surface coating treatment and ship deck metal surface treatment, and directly guided the formulation of standards and the specification of construction methods in the industry. With the continuous improvement and technical maturity of BlackRock shot blasting equipment, shot blasting technology and equipment have entered the fields of highway maintenance, bridge construction and airport maintenance in European and American developed countries. China's application in this area is still very few, only a few projects have used shot blasting process, and there is still a blank in the waterproof coating of expressway, municipal road and concrete bridge. GSD hopes to introduce this new shot blasting process to its counterparts in highway and bridge engineering maintenance and construction, and expects this new process and technology to be popularized.
1. Working principle of shot blasting process and equipment
1.1 working principle of shot blasting process and equipment
Shot blasting refers to the technology that the shot material (steel shot or sand) is shot onto the working surface at a high speed and a certain angle by mechanical method, so that the shot material can impact the working surface, and then the air flow cleaning of the supporting vacuum cleaner inside the machine can separate and recover the shot material and the cleaned impurities, so that the shot material can be reused. The shot blasting machine is equipped with dust remover, which can achieve dust-free and pollution-free construction, improve efficiency and protect the environment. Shot blasting machine can be divided into three types according to its walking form: hand push type, vehicle mounted type and self-propelled type.
During the operation of the shot blasting machine, the shot flow is controlled by controlling and selecting the particle size and shape of the shot, adjusting and setting the walking speed of the machine, so as to obtain different shot intensities and different surface treatment effects.
1.2 quality control of surface shot blasting
Shot blasting process and equipment control the surface condition after treatment through three parameters according to the different surfaces to be treated. Select the size and shape of shot; Traveling speed of equipment; The flow rate of shot. The above three parameters cooperate with each other to obtain different treatment effects and ensure the ideal roughness of the surface after shot blasting.
For example, using S330 steel shot with flow rate of 10a to treat C50 concrete surface, the roughness can reach 90; By treating the asphalt surface, the flooded oil layer can be removed and the roughness can reach 80; When processing steel plates, the cleanliness standard of SA3 can be met.
2 Application of shot blasting equipment
2.1 surface treatment of concrete bridge deck
Since the 1970s, waterproof layer has been widely used in concrete bridge deck pavement in European and American countries, which greatly reduces the damage of concrete bridges caused by water seepage and prolongs the service life of bridges. However, with the increase of traffic volume, there are diseases caused by insufficient bonding strength of waterproof layer, surface layer and bridge deck. In China, similar diseases often occur in concrete bridges, as well as concrete looseness, falling off and reinforcement corrosion caused by water seepage. One of the reasons for the above diseases is that the shot blasting treatment of the concrete surface can not completely remove the residual substances on the surface, and a certain rough surface is not retained to ensure the bonding strength between the waterproof layer and the bottom layer of the bridge deck.
The shot blasting process can clean and remove the laitance and impurities on the concrete surface at one time. It is important to roughen the concrete surface at the same time, so as to make the surface uniform and rough, and greatly improve the bonding strength between the waterproof layer and the concrete base. Moreover, in this process, the shot blasting process can fully expose the cracks and other diseases of concrete, so as to take remedial measures in advance.
2.2 tunnel maintenance
In China, cement concrete is generally used for the pavement in the tunnel due to the consideration of waterproof, fire resistance and oil resistance of materials. But at the same time, it also puts forward higher requirements for the skid resistance of long tunnel pavement. For the above two problems that are still difficult to solve in China, shot blasting is a treatment method with simple construction, small equipment investment, remarkable effect and environmental protection.
In recent years, with the recommendation of BlackRock blastrac users, there are more and more projects using shot blasting technology to treat bridge deck and tunnel. In the waterproof pavement of concrete bridge deck, shot blasting technology has been the requirement of process specifications in European and American countries, and is gradually accepted in China, such as Chongqing Tongyu tunnel, Guiyang yingpanpo tunnel, Kunming Shijiazhuang Expressway Qingshuigou tunnel, etc, Shot blasting technology is adopted to maintain the concrete pavement.
2.3 maintenance of Asphalt Pavement
Shot blasting equipment is widely used to improve the roughness and friction coefficient of asphalt pavement, so as to improve the adhesion of pavement and ensure driving safety. At the same time, it can also remove the attachments of asphalt pavement (such as fuel, engine oil, etc.), which are mainly used in the following aspects:
(1) During the construction of asphalt concrete overlay, the use of shot blasting process for road surface pretreatment can ensure the cleanness of the road surface, increase the surface roughness, strengthen the bonding between the overlay and the original road surface, and greatly increase the durability of its structure; When slurry seal and resin material cover are used, shot blasting can greatly improve the bonding strength between resin cover and original base, improve the quality of slurry seal and prolong the service life of pavement.
(2) The shot blasting process can be directly used on the asphalt pavement, such as roughening the surface of the turning section to improve the skid resistance.
(3) It can directly remove the surface oil flashing of asphalt pavement and improve the reduction of anti sliding performance caused by oil flashing.
(4) Shot blasting process can also be applied to the removal of sign lines.
In China, the impact of surface roughness on traffic has not attracted extensive attention, but the traffic accidents caused by pavement slip are increasing every year. Shot blasting equipment can flexibly deal with small-area sections and completely restore its anti sliding performance.
The asphalt surface treated by shot blasting process not only cleans the attachments on various surfaces, but also increases the roughness of asphalt surface and improves the performance of asphalt pavement. Moreover, the equipment construction is simple, convenient and flexible.
2.4 anti corrosion coating of steel bridge deck
The application of shot blasting technology in anti-corrosion coating of steel bridge has been fully affirmed in China. For most bridges under construction and already built, shot blasting process is selected for surface cleaning and roughness treatment before anti-corrosion primer or other spraying, such as the Second Yangtze River Bridge, Jiangyin Bridge, Junshan bridge, Baishazhou bridge, Shanghai Lupu Bridge, etc. The steel bridge surface treated by shot blasting process can meet the cleanliness requirements of sa2.53 steel plate, and the roughness can be controlled to meet the coating requirements. Moreover, the whole process is dust-free operation and easy to move.
2.5 municipal roads and paved pavement
Various road pavements in the city can be cleaned by shot blasting machine to remove the signs and markings of the road surface. The road surface can be roughened at busy intersections to improve the roughness and friction coefficient of the road surface.
2.6 preventive maintenance of airport runway
Concrete and asphalt runways remove tire tracks (except rubber), remove markings, restore and increase the surface roughness of airport runways, and improve the friction coefficient of runways.
3 Summary
In China, shot blasting technology has been widely used in the construction of steel bridge deck, and has also been applied in the restoration and maintenance of skid resistance of some concrete pavement; However, as a new process, we have just begun to apply it in the waterproof bottom treatment of concrete bridges and the restoration of anti sliding performance of other highways, as well as other fields that have been applied in European and American countries.
1. Working principle of shot blasting process and equipment
1.1 working principle of shot blasting process and equipment
Shot blasting refers to the technology that the shot material (steel shot or sand) is shot onto the working surface at a high speed and a certain angle by mechanical method, so that the shot material can impact the working surface, and then the air flow cleaning of the supporting vacuum cleaner inside the machine can separate and recover the shot material and the cleaned impurities, so that the shot material can be reused. The shot blasting machine is equipped with dust remover, which can achieve dust-free and pollution-free construction, improve efficiency and protect the environment. Shot blasting machine can be divided into three types according to its walking form: hand push type, vehicle mounted type and self-propelled type.
During the operation of the shot blasting machine, the shot flow is controlled by controlling and selecting the particle size and shape of the shot, adjusting and setting the walking speed of the machine, so as to obtain different shot intensities and different surface treatment effects.
1.2 quality control of surface shot blasting
Shot blasting process and equipment control the surface condition after treatment through three parameters according to the different surfaces to be treated. Select the size and shape of shot; Traveling speed of equipment; The flow rate of shot. The above three parameters cooperate with each other to obtain different treatment effects and ensure the ideal roughness of the surface after shot blasting.
For example, using S330 steel shot with flow rate of 10a to treat C50 concrete surface, the roughness can reach 90; By treating the asphalt surface, the flooded oil layer can be removed and the roughness can reach 80; When processing steel plates, the cleanliness standard of SA3 can be met.
2 Application of shot blasting equipment
2.1 surface treatment of concrete bridge deck
Since the 1970s, waterproof layer has been widely used in concrete bridge deck pavement in European and American countries, which greatly reduces the damage of concrete bridges caused by water seepage and prolongs the service life of bridges. However, with the increase of traffic volume, there are diseases caused by insufficient bonding strength of waterproof layer, surface layer and bridge deck. In China, similar diseases often occur in concrete bridges, as well as concrete looseness, falling off and reinforcement corrosion caused by water seepage. One of the reasons for the above diseases is that the shot blasting treatment of the concrete surface can not remove the residual substances on the surface, and a certain rough surface is not retained to ensure the bonding strength between the waterproof layer and the bottom layer of the bridge deck.
The shot blasting process can clean and remove the laitance and impurities on the concrete surface at one time. It is important to roughen the concrete surface at the same time, so as to make the surface uniform and rough, and greatly improve the bonding strength between the waterproof layer and the concrete base. Moreover, in this process, the shot blasting process can fully expose the cracks and other diseases of concrete, so as to take remedial measures in advance.
2.2 tunnel maintenance
In China, cement concrete is generally used for the pavement in the tunnel due to the consideration of waterproof, fire resistance and oil resistance of materials. But at the same time, it also puts forward higher requirements for the skid resistance of long tunnel pavement. For the above two problems that are still difficult to solve in China, shot blasting is a treatment method with simple construction, small equipment investment, remarkable effect and environmental protection.
In recent years, with the recommendation of BlackRock blastrac users, there are more and more projects using shot blasting technology to treat bridge deck and tunnel. In the waterproof pavement of concrete bridge deck, shot blasting technology has been the requirement of process specifications in European and American countries, and is gradually accepted in China, such as Chongqing Tongyu tunnel, Guiyang yingpanpo tunnel, Kunming Shijiazhuang Expressway Qingshuigou tunnel, etc, Shot blasting technology is adopted to maintain the concrete pavement.
2.3 maintenance of Asphalt Pavement
Shot blasting equipment is widely used to improve the roughness and friction coefficient of asphalt pavement, so as to improve the adhesion of pavement and ensure driving safety. At the same time, it can also remove the attachments of asphalt pavement (such as fuel, engine oil, etc.), which are mainly used in the following aspects:
(1) During the construction of asphalt concrete overlay, the use of shot blasting process for road surface pretreatment can ensure the cleanness of the road surface, increase the surface roughness, strengthen the bonding between the overlay and the original road surface, and greatly increase the durability of its structure; When slurry seal and resin material cover are used, shot blasting can greatly improve the bonding strength between resin cover and original base, improve the quality of slurry seal and prolong the service life of pavement.
(2) The shot blasting process can be directly used on the asphalt pavement, such as roughening the surface of the turning section to improve the skid resistance.
(3) It can directly remove the surface oil flashing of asphalt pavement and improve the reduction of anti sliding performance caused by oil flashing.
(4) Shot blasting process can also be applied to the removal of sign lines.
In China, the impact of surface roughness on traffic has not attracted extensive attention, but the traffic accidents caused by pavement slip are increasing every year. Shot blasting equipment can flexibly deal with small-area sections and completely restore its anti sliding performance.
The asphalt surface treated by shot blasting process not only cleans the attachments on various surfaces, but also increases the roughness of asphalt surface and improves the performance of asphalt pavement. Moreover, the equipment construction is simple, convenient and flexible.
2.4 anti corrosion coating of steel bridge deck
The application of shot blasting technology in anti-corrosion coating of steel bridge has been fully affirmed in China. For most bridges under construction and already built, shot blasting process is selected for surface cleaning and roughness treatment before anti-corrosion primer or other spraying, such as the Second Yangtze River Bridge, Jiangyin Bridge, Junshan bridge, Baishazhou bridge, Shanghai Lupu Bridge, etc. The steel bridge surface treated by shot blasting process can meet the cleanliness requirements of sa2.53 steel plate, and the roughness can be controlled to meet the coating requirements. Moreover, the whole process is dust-free operation and easy to move.
2.5 municipal roads and paved pavement
Various road pavements in the city can be cleaned by shot blasting machine to remove the signs and markings of the road surface. The road surface can be roughened at busy intersections to improve the roughness and friction coefficient of the road surface.
2.6 preventive maintenance of airport runway
Concrete and asphalt runways remove tire tracks (except rubber), remove markings, restore and increase the surface roughness of airport runways, and improve the friction coefficient of runways.
3 Summary
In China, shot blasting technology has been widely used in the construction of steel bridge deck, and has also been applied in the restoration and maintenance of skid resistance of some concrete pavement; However, as a new process, we have just begun to apply it in the waterproof bottom treatment of concrete bridges and the restoration of anti sliding performance of other highways, as well as other fields that have been applied in European and American countries.