How to operate a shotcrete machine?

Shotcrete machine is a kind of mechanical equipment that sprays concrete mixture directly on the surface of buildings or structures to strengthen the surface of buildings or form new structures. It is the core equipment in sprayed concrete construction. How to operate a concrete shotcrete machine? This may be a problem that many beginners, operators, builders or workers need to face. You can refer to the following steps to realize the operation of most concrete spraying machines. Welcome to view the best safe operation procedures for shotcrete machines.

Preparatory work for Shotcrete Machine Operations

1. Check the concrete sprayer machine. Check whether there is debris left in the hopper. Loosen the pressing mechanism on the rubber plate, remove the arc plate and the jacking screw to check the direction of the rubber plate and the rotating liner, if it rotates counterclockwise, it means the direction is correct. Jog the motor to check the steering of the steel liner, if it rotates counterclockwise, it means the steering is correct. Tighten the pressing mechanism on the top of the rubber plate and the jacking screw on the outside of the arc plate to adjust the gap between the rubber plate and the steel liner to make the combination tight and stable. Drain the oil and water from the oil-water separator. Open the stop valve to check the air leakage around the rubber plate, and adjust the air pressure according to the length of the feeding pipe, and blow the pipe with air for 2-3 minutes. Idle test the machine and run motor to check if it is normal.
2. Check the spray gun. The spray operator is responsible for dismantling the parts of the spray gun, checking the wear of the incoming pipe, water ring and its connecting parts, and whether the water hole is blocked. If there is any damage, the parts should be repaired and replaced immediately.
3. Check the delivery pipeline. Air supply and water supply test check whether there is air leakage and water leakage in the air and water pipes, whether there is air leakage and material leakage in the material delivery pipeline. Beat the material delivery pipeline to check the wear and tear and whether the discharge elbow is blocked.
4. Check whether the pressure gauge is flexible.

Working process of concrete spraying machine

1. Before the spraying concrete operation starts, the old belt should be laid on the spraying site first, so as to collect the rebound material, and the rebound rate should not exceed 10%. Boil the water and open the wind, adjust the water volume, and keep the wind pressure not lower than 0.4MPa. The water pressure should be about 0.1MPa higher than the wind pressure. The amount of water added should be controlled according to the shooter’s experience.
2. The sprayer operates the nozzle to wash the rock surface from top to bottom.
3. The concrete spraying machine is powered, and the material is sprayed.
4. Adjust the amount of wind and water again according to the feeding situation to ensure that the spray surface has no dry spots, no flow, strong adhesion and less rebound material.
5. The spraying hand sprays in sections from bottom to top, first on the wall and then on the arch.
6. When spraying, the nozzle should be as vertical as possible to the sprayed surface, and the included angle should not be less than 70 degrees.
7. When spraying, the trajectory of the nozzle should be in a spiral shape, moving evenly and slowly according to the method of pressing a circle to a semicircle with a diameter of 200-300mm.
8. The thickness of the concrete sprayed by the concrete sprayer is 50-70mm at one time, and it should be re-sprayed in time, and the interval between re-spraying should not exceed 2 hours. Otherwise, high-pressure water should be used to flush the sprayed surface again.
9. There should be two people, one person holds the nozzle to spray, and the other person assists in lighting and is responsible for communication, observing the safety of the roof and the quality of spraying.

Concrete sprayer shutdown operation

1. After the shotcrete operation is finished, operate in the order of stopping the material first, then the water, then the power, and finally the wind.
2. After the spraying work is over, remove the spray head, clean the water ring and the mortar or materials inside and outside the spray machine, and install the wind and water pipe.
3. Clean up and collect the rebound material, and use up the on-duty mixing material.
4. Sprinkle the concrete for maintenance after 2 hours, and take the core to test the strength after 28 days.

Precautions for Safe Operation of Shotcrete Machine

1. When spraying in batches, re-spraying should be carried out after the final setting of the previous concrete. If spraying is carried out after one hour of final setting, the surface of the spray layer should be cleaned with water first. If there are overcuts or cracks and low depressions, it should be resprayed and leveled first, and then sprayed normally.
2. It is strictly forbidden to point the nozzle at the personnel.
3. During the spraying process, in case of pipe blockage, wind power failure and other failures, the water door should be closed immediately, and the nozzle should be placed downward to prevent water from flowing into the feeding pipe; when dealing with blocked pipes, the feeding pipe should be conveyed by tapping.
4. Sprayers should wear dust masks, latex gloves and glasses.
5. After the sprayed concrete work is finished, the sprayed layer shall be sprayed once every shift within seven days, and once every day after seven days, and the maintenance shall be continued for 28 days.
6. The operator of the Shotcrete Machine must undergo special training, be familiar with the performance structure and working principle of the spraying machine, and be able to eliminate general faults and carry out daily repairs and maintenance.
7. The air inlet is well sealed to prevent dust from being blown by air leakage; the exhaust port is unblocked and the exhaust gas is discharged smoothly; the joints of the spraying pipes are firm, well sealed and neatly placed.

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