1) Check the wear between the cutting ring and the eye plate, which is the key to the success or failure of direct water cleaning. If the wear of the cutting ring and the eye plate is not serious, the distance between the cutting ring and the eye plate is less than 0.1mm, and there is no groove scratch of more than 1mm between them, the direct water method can be used. 

 2) After pumping the concrete, pump 0.15-0.25m\+3 mortar with a water-cement ratio of 1:1.5 or 1:2, then fill the distribution valve with water, start pumping, and pump the concrete to the Pouring location until clean water flows out from the output end of the delivery pipe. If the pipeline is shorter and the cleaning effect is better, the cleaning process ends here. 

 3) When the pipeline is long or the cleaning effect is not good, open the hopper discharge door, turn on the reverse pump, and flush the hopper and distribution valve. If pumping upwards and the height is more than 20m, use a wooden hammer to strike the bent pipe at the bottom of the vertical part. If the knocking sound is low, disassemble the bent pipe and pour out the large aggregates that may be accumulated. 

 4) Close the discharge door and pump clean water until the clean water flows out from the output end of the conveying pipe. The advantage of the direct pumping method is that it is not necessary to remove the material outlet pipe and add a cleaning ball, which saves time, and the pumping is easier to succeed, which is especially convenient for cleaning short pipelines. 

Disadvantages: ① The water consumption is large and the pumping water must be continuous, and the water can be easily discharged at the pouring site; ② If there is a vertical upward pipeline, the elbow must be removed; ③ When the transmission pipeline is long, it is easy to have residues in the pipeline; ④ For distribution Valve tightness requirements are strict.

2 Dismantling the material pipe method

 1) After pumping the concrete, reverse the pump for 1-2 cycles to eliminate the pressure in the conveying pipe. If pumping upwards, the shut-off valve must be closed first to prevent the concrete from flowing back, and then the discharge pipe must be removed. 

 2) Open the hopper discharge door, and the reverse pump will flush the distribution valve, the concrete cylinder and the concrete in the hopper. 

 3) Take out some of the concrete at the mouth of the first 6B or 5B conveying pipe, and insert it into a water-soaked cleaning ball or a cylindrical cleaning piston. 

 4) Close the discharge door of the distribution valve, if there is a stop valve, open it, and pump clean water until the piston is pumped out from the output end of the conveying pipe. 

The advantage of the method of removing the material pipe is that the pipe cleaning is relatively clean, and the flow rate of the water source can be lower and can be suspended. The disadvantage is that it is difficult to connect again after the discharge port is disassembled, which is time-consuming and labor-intensive. 

3 plus piston method

 1) Use 10 to 20 cement bags to roll into a cylindrical body with a diameter slightly smaller than the diameter of the conveying cylinder, a slightly pointed head, and a length of about 400mm, bundle it with thin iron wires, and lightly tie the cleaning ball to the tail of the cylindrical body with iron wire. soaked. 

 2) After pumping the concrete, reverse the pump for 1-2 cycles to eliminate the pressure in the conveying pipe, and press the button to make the concrete cylinder piston retreat to the last point. If pumping upwards and there is a shut-off valve, it must be closed first to prevent backflow of concrete. 

 3) Remove the discharge pipe, open the hopper discharge door, and the reverse pump will flush the distribution valve, the concrete cylinder and the concrete in the hopper. 

 4) Close the hopper discharge door, add water to the hopper, when the water is added to the height of 2/3 of the diameter of the concrete cylinder, put the head of the column body into the concrete cylinder towards the direction of the distribution valve, and use a length of about 1m and a diameter of about 30mm The wooden sled sticks against the cylindrical body, and continue to add water to the height of the centerline of the stirring shaft.

 5) Withdraw the crowbar, start pumping quickly, and continue to add water until the cylinder is pumped out from the output end of the delivery pipe. The advantage of the piston method is that the cleaning of the pipeline is relatively clean, the flow rate of the water source can be lower and can be suspended, and the trouble of removing the material outlet and the elbow is reduced. The disadvantage is that the operation requirements are high, and the distribution valve is easy to cut off the cylindrical body.

The above three concrete pump washing methods have their own advantages and disadvantages. Among them, the most reliable method is the method of removing the material pipe, and the simplest method is the method of adding a piston. If the conveying distance is short, the direct water method is also a good choice. The specific method should be determined according to the actual situation of the construction. In short, it should be effective and economical.