Cause Analysis and Preventive Measures of Concrete Pumping blockage.
First, improper operation likely to cause blockage
1, the operator is not concentrated
Pump operator should focus on the construction of pumping, always pay attention to the readings of the pump pressure gauge, once the pressure gauge readings suddenly increased, should be immediately anti-pump 2-3 trip, and then pump, plugging can be ruled out . If the anti-pump has been carried out (positive pump several operating cycles, has not yet ruled out blocking pipe, should be timely removal of pipe cleaning, or will plug the pipe even more serious.
2, improper pumping speed selection
Pumping, the speed of choice is critical, the operator can not blindly map fast, sometimes haste makes waste. When pumping for the first time, due to pipeline resistance, this time should be low-speed pumping, pumping normal, may be appropriate to improve the pumping speed. When there is a pipe blocking signs or a car concrete slump is small, should be low-speed pumping, will block the tube in the bud.
3, more than expected feed control inappropriate
Pumping, the operator must at any time to observe the remaining material in the hopper, the remaining material shall not be lower than the mixing shaft, if too much material, easy to inhale the air, causing blockage. Hopper in the material can not be piled too much, should be lower than the fence, in order to timely clean up coarse aggregate and large aggregate. When a car concrete slump is small, the remaining material can be lower than the mixing shaft, control in the "S" tube or suction port to reduce the mixing resistance, swing resistance and suction resistance. This method is only applicable to "S" valve series concrete pump.
4, when the concrete slump too small to take measures to find a bucket of concrete slump is very small, can not be pumped, it should be timely to let the concrete from the bottom of the hopper, if the easy way, forced pumping can easily cause blockage tube. Do not add water in the hopper stirring.
5, downtime is too long
Shutdown period should be every 5 ~ 10min (specific time as the day temperature, concrete slump, concrete setting time may be) to open a pump to prevent plugging. For downtime is too long, the initial setting of the concrete, should not continue to pump.
6, the pipeline is not clean
The last pumping is completed, the pipeline is not clean, will cause the next pumping block. So every time the pump must be completed in accordance with the operating rules of the pipeline clean.
Second, the pipeline connection causes plugging
Pipe connection error can easily lead to plugging. Take over the following principles should be followed:
1, pipe layout should be based on the shortest distance, the least elbow and the largest elbow to pipe, to minimize transmission resistance, it reduces the possibility of blocking.
2, the pump outlet cone pipe, not directly connected to the elbow, at least 5mm should be connected to the straight tube, then take the elbow.
3, pumping the way to take over, each can only be connected to a root, and the application of water lubrication pipe wall, side by side to make the air, or easily lead to blockage.
4, the vertical down the pipe, the exit should be installed anti-segregation device to prevent plugging.
5, high-level pumping, the length of the horizontal pipeline should generally not be less than 15% of the length of the vertical pipe, and should be in the horizontal pipe line access valve. Shutdown time of more than 5min, should be closed valve to prevent the concrete back, leading to blockage. From the horizontal turn when the vertical 90 degree bend, bending radius should be greater than 500mm.
Third, the concrete or mortar caused by the segregation of plugging
Concrete or mortar with water, easily lead to segregation. Sometimes in the pumping mortar, blocking occurs when the phenomenon is because the mortar and pipe in direct contact with water, the mortar caused by segregation, the precaution is: the water before the pump wet pipe, the lowest point from the pipeline pipe joints Release, all the water to let go, or pump water, before pumping mortar, put a sponge ball, the mortar and water separately.
Pumping is completed cleaning pipes, but also into a sponge ball, the water and concrete separately, or easily lead to blockage.
Fourth, local leakage caused by plugging the slurry
As a result of mortar leakage, on the one hand affect the quality of concrete, on the other hand leakage of slurry, will lead to reduced concrete slump and pumping pressure loss, resulting in plugging. Leak slurry of the main reasons are the following:
1, the transmission pipe joints sealed lax
Conveyor pipe joints lax, pipe loose or damaged seals and leakage of pulp. At this time should be tightened tube card or replace the ring.
2, the gap between the lens plate and the cutting ring is too large
Glass plate and cutting ring wear is serious, the gap between the larger. When the gap is greater than% -, by adjusting the special-shaped bolts to narrow the gap between the lens plate and cutting ring, if you can not adjust, should immediately replace the wear parts. This method is only applicable to "S" valve series concrete pump.
3, concrete piston wear serious
Operators should always observe the water tank is turbid, with or without mortar, once the water has been turbid or water mortar, indicating that the concrete piston has been worn, this time should be replaced piston, or leakage due to leakage and pressure loss caused by blocking Tube, while also exacerbating the wear of piston and delivery cylinder.
4, due to serious wear and tear caused by concrete slurry tank leakage slurry
If the piston after each change, the water tank quickly become turbid, and the piston is good, then the delivery tank has been worn, then replace the delivery tank.