Concrete pumping pipe plugging the reasons and preventive measures: 1, improper operation likely to cause blockage: 1.1 operators do not concentrate pump operator in pumping construction should focus on, always pay attention to the reading of the pumping pressure gauge, once found Suddenly increased pressure gauge readings should immediately anti-pump 2-3 trip, then the pump, plugging can be ruled out. If you have carried out the anti-pump (positive pump several operating cycles, has not ruled out pipe plugging, should promptly demolition pipe cleaning, otherwise it will make the pipe plugging more serious. 1.2 pumping speed improper selection pump, the speed of the key, The operator can not blindly map fast, and sometimes the speed is not up to the first pump, due to the larger pipeline resistance, at this time should be low-speed pumping, pump normal, may be appropriate to increase the pumping speed.When there are indications of blockage or When the slump of a certain car is small, it should be pumped at a low speed, and the plugging pipe will be eliminated in the sprouting state. 1.3 When the material quantity control is not suitable for pumping, the operator must observe the excess material in the hopper at any time and the remaining material shall not be low In the mixing shaft, if the remaining material is too little, very easy to inhale the air, leading to plugging tube material in the hopper can not pile too much, should be lower than the fence, in order to timely clean up the coarse aggregate and large aggregate. When a car concrete slump is small, the remaining material may be lower than the stirring shaft, control the "S" pipe or suction port above, in order to reduce the stirring resistance, wobble resistance and suction resistance .This method is only applicable to the "S" valve Series of concrete . 1.4 When the concrete slump is too small to take improper measures When one bucket of concrete found slump is very small, can not be pumped, the concrete should be promptly let go from the bottom of the hopper, if the covet effort, forced pumping can easily lead to block Tube should not be mixed with water in the hopper 1.5 Downtime is too long Shutdown should be every 5 ~ 10min (specific time depending on the day temperature, concrete slump, initial setting time of concrete) to open the pump once to prevent plugging pipe For the downtime is too long, the initial setting of the concrete, should not continue to pump. 1.6 pipe is not clean and clean the last pump is completed, the pipe is not cleaned, will cause the next pump when plugged. So each time the pump is completed Must be in accordance with operating procedures to clean the pipeline 2. Pipe connection caused by plugging: pipe connection errors can easily lead to plugging. Take over the following principles should be followed: the pipeline layout should be based on the shortest distance, the least bend and The largest elbow pipe to minimize transport resistance, also reduces the possibility of plugging pipe. Pump outlet cone Department, not directly connected Pipe, at least should access more than 5mm straight pipe, then elbow .Pump halfway takeover, can only be connected to one, and the application of water to lubricate the inner wall of the pipe, and exhaust air, or can easily lead to blockage Vertical downward pipe, outlet should be equipped with anti-segregation device to prevent plugging pipe.High-level pumping, the length of the horizontal pipe should generally not less than 15% of the length of the vertical pipe, and should be connected in the horizontal pipe Into the pipeline shut-off valve. Shutdown time exceeds 5min, the shut-off valve should be closed to prevent the concrete backflow, leading to plugging pipe. Turn 90 degrees from the horizontal bend when the bending radius should be greater than 500mm. 3, the segregation of concrete or mortar Plugging: Concrete or mortar encounter with water, can easily lead to segregation.Pumping mortar sometimes occurs, the phenomenon of plugging occurs because mortar and water in the pipe after direct contact with the mortar segregation caused by the prevention is : After the pump is wetted with water before the pipe, from the lowest point of the pipeline will be loose pipe fittings, the excess water will be let go, or after the pump, before pumping mortar, put a sponge, the sand Separated from the water. Pumping is completed cleaning the pipeline, but also into a sponge ball, the water and concrete separation, otherwise easily lead to plugging. 4, the local leakage caused by the plugging pipe: leakage of mortar, on the one hand affect the quality of concrete, on the other hand after the slip, will lead to the slump of concrete and pumping pressure to reduce the loss, leading to plugging. Leakage of the main reasons for the following: 4.1 Conveyor pipe joints lax transmission pipeline joints lax seal, pipe loose or damaged seal leakage plasma. At this point you should fasten the tube card or replace the seal. 4.2 Glasses plate and the gap between the cutting ring is too large glasses plate and cutting ring wear serious, the gap between the two become larger. When the clearance is greater than% -, the adjusting bolt should be used to narrow the gap between the lens plate and the cutting ring. If the clearance can not be adjusted, the worn part should be replaced immediately. This method is only applicable to "S" valve series concrete pump. 4.3 serious wear and tear of concrete pistons The operator should always observe the water in the tank is turbid, with or without mortar, once found that the water has turbidity or water in the mortar, indicating that the concrete piston has been worn, then the piston should be replaced promptly, otherwise, Pressure loss and lead to blockage, but also exacerbate the piston and cylinder wear. 4.4 Leakage caused by severe wear of concrete conveying cylinder If the water in the water tank becomes turbid quickly after each replacement of the piston and the piston is good, it indicates that the conveying cylinder is worn and the conveying cylinder needs to be replaced. 5, non-qualified pumping concrete blockage caused by the pipe: for pumping concrete must meet the requirements of pumping concrete, not all concrete can be used to pump, non-qualified pumping concrete will exacerbate the pump Wear, and often appear plugging, squibing and so on. 5.1 Concrete slump is too large or too small Slump concrete size directly reflects the good or bad concrete flow resistance, concrete transport resistance decreases with increasing slump. Pumped concrete slump generally in the range of 8 ~ 18cm, for long-distance and high-altitude pumping generally need to strictly control the 15cm or so. Slump is too small, will increase the delivery pressure, aggravate the equipment wear and tear, and lead to blockage. Slump is too large, under high pressure concrete segregation caused by blocking tube. 5.2 Sand content is too small, unreasonable coarse aggregate gradation According to the source of fine aggregate can be divided into: river sand, artificial sand (ie, the mechanism of sand), sea sand, mountain sand, river sands best pumpability, Mechanism of pumpability is the worst. Fine aggregate by particle size can be divided into: coarse sand, medium sand, fine sand, which can pump the best in sand. According to the shape of coarse aggregate can be divided into: pebbles, gravel. Pebble pumpability is better than gravel. The maximum aggregate size of the pipeline and the minimum diameter also has a relationship, the largest pebble particle size should be less than 1/3 diameter, the maximum size of the gravel should be less than 1/4 diameter, otherwise it is easy to cause blockage. Due to the different materials, fine aggregate content (ie, sand content), coarse aggregate gradation there is an optimal value. Under normal circumstances, the sand content should not be too low, should be greater than 40%, the content of large-size coarse aggregate should not be too high. Reasonable choice of sand content and determine the aggregate gradation, to improve pumping performance of concrete and prevent plugging is essential. 5.3 Too little or too much cement The cement in the pumping of concrete, cementing and lubrication, while the cement has good water retention properties, so that the concrete is not easy bleeding in the pumping process, the amount of cement there is an optimal value If the amount of cement is too small, it will seriously affect the suction performance of concrete, while increasing the pumping resistance, concrete water retention becomes worse, easy bleeding, segregation and plugging occurred. Under normal circumstances, the content of cement per cubic meter of concrete should be greater than 320Kg, but not too large, too much cement, will increase the viscosity of concrete, resulting in increased transport resistance. In addition the amount of cement and the shape of the aggregate is also related to the aggregate surface area, the need to wrap the slurry should be more, accordingly, the greater the content of cement. Therefore, a reasonable determination of the amount of cement, to improve the pumpability of concrete, prevention of plugging is also very important. 5.4 Addition of additives is not reasonable Many types of additives, such as: air entrainer, water reducer, superplasticizer, retarder, pumping agent, etc., according to the strength of concrete and cement varieties, a reasonable choice Admixture, to improve the pumping performance of concrete play a very important role. Unreasonable admixtures will make the concrete pumpability and fluidity worse, leading to blockage. 6, too little mortar or unqualified plugging caused by the pipe: 6.1 mortar dosage is too small because the first pump, mixing the host, concrete truck mixing tank, hopper, pipes and so on to absorb part of the mortar, if the amount of mortar too Less, will lead to some of the delivery pipe is not lubricated, leading to blockage. Correct amount of mortar should be required for every 200m pipe about 0.