Application and operation of concrete shotcrete machine

November 01, 2018


Concrete jet machine, also known as concrete shotcrete machine, mainly uses compressed air to pass concrete through the material chamber into the spray equipment that is continuously transported along the pipeline and sprayed onto the construction surface. The concrete jet machine is mainly divided into two types: dry concrete jet (right) and wet concrete jet. The former is dry-mixed by pneumatic conveying, and mixed with pressurized water at the nozzle; the latter is made of pneumatic or concrete pump. The concrete mixture is conveyed through a nozzle. Concrete jets are widely used in underground concrete, hydropower projects, wells, tunnels, culverts and other shotcrete construction operations.

Concrete shotcrete machines still need to do a lot of preparation work before the shotcreting work, and there are still many things to be aware of during the shotcreting process.

Preparation work required for the shotcrete before construction

1. Preparation for inspection of the work site. Check whether the quality of the tunneling excavation specification is qualified, and the unqualified section should be processed first. Knock the state to ask the top, eliminate the top state pumice, clean up the two states, and to achieve the depth of the two states. Obstacles that affect the spraying operation must be removed, and can not be removed, such as cable lines, air ducts, etc. need to be protected and covered. When the jet and the sprayer cannot be directly contacted, a dedicated contact signal should be set. Lay the iron plate in the injection section to prepare for the recycling of the rebound.

2. Check the concrete jet machine. Check if there is any leftovers in the hopper. The pressing mechanism on the rubber plate is relaxed, the curved plate and the top screw are removed, and the rubber plate and the rotating lining are turned, and if rotated in a counterclockwise direction, the steering is correct. Jog the motor to check the steering of the steel liner, such as counterclockwise rotation, indicating that the steering is correct. Tighten the pressing mechanism on the rubber plate and the top screw on the outside of the curved plate to adjust the gap between the rubber plate and the steel liner to make the combination tight and stable. The oil and water separator is drained. Open the shut-off valve to check the air leakage around the rubber plate, and adjust the air pressure according to the length of the feed pipe. Use the air to blow the pipe for 2-3 minutes. Whether the no-load test run motor is normal.

3. Check the spray gun. The spray operator is responsible for unloading the components of the spray gun, checking the wear of the feed pipe, the water ring and its connecting parts, whether the water hole is blocked or not, and modifying and replacing the damaged parts immediately.

4. Check the delivery line. Air supply, water supply test to check the wind, water pipe with or without air leakage, the conveyor line with or without air leakage, knocking the pipeline to check the wear and tear, the discharge elbow is blocked.

5. Check if the pressure gauge is flexible.

Concrete jet precautions

1. In the case of split injection, the double spray should be carried out after the last enthalpy. If the spray is finished after one hour of final condensation, the surface of the spray layer should be washed with water first. If there is overcut or crack low recess, it should be sprayed and leveled first, then sprayed normally.

2. It is strictly forbidden to point the nozzle at the person

3. During the spraying process, if there is a fault such as blockage, wind and power failure, the water gate should be closed immediately, and the nozzle should be placed down to prevent water from flowing into the delivery pipe; when the pipe is blocked, the pipe is used to pass the pipe.

4. Jet personnel should wear dust masks, latex gloves and glasses.

5. After the shotcrete work is finished, the spray layer is within seven days, and each shift is sprinkled once. After 7 days, it is sprinkled once a day for 28 days.

6. The concrete jet machine operator must be specially trained to be familiar with the performance structure and working principle of the jet machine, and can eliminate general faults and carry out routine maintenance and maintenance.

7. The air inlet is well sealed to prevent dust from blowing dust; the exhaust port is unblocked, and the exhaust gas is discharged smoothly; the spray pipe joint is firm, well sealed and placed neatly.

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