The cleaning of the concrete pump hopper is an indispensable important step after pumping. The good cleaning method can not only clean the conveying pipeline, but also transport all the concrete in the pipeline to the pouring place, which not only wastes waste, but also is economical and environmentally friendly. There are three main types of water washing methods commonly used for S-tube concrete pumps, which are described below.

Direct watering

1) Check the wear between the cutting ring and the wear plate. If the cutting ring and the wear plate are not seriously worn, the spacing between the cutting ring and the wear plate is <0.1mm, and there is no groove scratch of more than 1mm between

 them, Then using the direct watering way.

2) After pumping, pump 0.15~0.25m+3 mortar with water ratio of 1:1.5 or 1:2, then fill the distribution valve with water, start pumping, pump the concrete to the location until the convey pipe to deliver the clean water. If the pipe is short and the cleaning effect is good, the cleaning process ends here.

3) When the pipe is long or the cleaning effect is not good, open the hopper discharge door, the reverse pump, and rinse the hopper and distribution valve. If pumping and up to the height is >20m, you can use a wooden hammer to strike the bottom part of the vertical part. If the tapping sound is low, you need to disassemble the elbow and pour out the large aggregate that may accumulate.

4) Close the discharge door and pump clean water until the water flows out from the output end of the delivery tube.

The advantages of the direct watering method: it is not necessary to remove the material feeding tube and the cleaning ball, which saves time and is easy to pump, which is especially convenient for cleaning short pipelines.

Disadvantages: 1. Water consumption is large and the pump water must be continuous, water is easy to be placed at the pouring place; 2. If there is a vertical upward pipe, usually the bend pipe must be dismantled; 3. When the pipeline is long, there is easy to remain in the pipeline; 4. Have strictly requirement on the sealing of the distribution valves.

Dismantling method

1) After pumping, the pump is reversed for 1~2 cycles to eliminate the pressure in the conveying pipe. If pumping up, the shut-off valve must be closed to prevent backflow and then remove the discharge pipe.

2) Open the hopper discharge door, and by reverse pump to clean the concrete clearly in the distribution valve, the sump and the hopper.

3) Pull out the concrete in mouth of the first 6B or 5B delivery pipe and insert it into the water-washing cleaning ball or cylindrical cleaning piston.

4) Close the distribution valve’s discharge door, open it if there is a shut-off valve, pump clean water until the piston is pumped from the output end of the delivery pipeline.

The advantage of the stripping method is that the pipeline cleaning is relatively clean, and the flow rate of the water source can be low and suspended. The disadvantage is that it is difficult to connect again after the discharge port is disassembled, which is cost time and energy.

Piston method

1) Use 10 to 20 cement bags to roll into a columnar body with a diameter slightly smaller than the conveying cylinder diameter, a slightly pointed head and a length of about 400 mm, bundled with fine iron wire, and lightly clean the ball with the wire at the end of the columnar body.  Soaked.

2) After pumping, turn the pump back for 1~2 cycles, eliminate the pressure in the conveying pipe, and press the button to make the cylinder piston retreat to the last point. If pumping up and having a shut-off valve, it must be closed to prevent back flow.

3) Remove the discharge pipe, open the hopper discharge door, and rinse the concrete in the distribution valve, the sump and the hopper.

4) Close the hopper discharge door and add water to the hopper. When the water is added to the diameter of the cylinder 2/3, the head of the column is loaded into the cylinder in the direction of the distribution valve. The length is about 1 m and the diameter is about 30 mm. The wooden sled bar holds the columnar body and continues to add water to the centerline of the mixing shaft.

5) Withdraw the crowbar, start the pumping quickly, and continue to add water until the column is pumped out from the output end of the tube.

The advantage of the addition of the piston method is that the pipeline cleaning is relatively clean, the flow rate of the water source can be low and suspended, as well as reducing the trouble of the material outlet and the bending pipe.

The disadvantage is that the operation requirements are high, and the distribution valve is easy to cut the column body.

The above three concrete pump washing methods have their own advantages and disadvantages. The most reliable one is the method of removing the material. The simplest method is to add the piston method. If the conveying distance is short, the direct watering method is also a good choice.  While the specific method should be determined according to the actual conditions of the construction, and in a word, it should be both effective and economical.