304 North Cardinal St.
Dorchester Center, MA 02124
304 North Cardinal St.
Dorchester Center, MA 02124
To ensure that the concrete pump truck can work in the specified technical state, reduce maintenance costs, improve the reliability and life of use, it is necessary to carefully implement its use and maintenance procedures.
In basic construction projects, a lot of construction machinery will be used, especially the concrete pump truck indispensable. To ensure the safety of construction and construction quality, concrete pump truck operators must be familiar with the following precautions for their safe use.
Concrete pump truck operators must undergo special training before they are allowed to operate. Can be familiar with the mechanical properties of the pump truck, master the operation methods and precautions of the pump truck, produce in earnest to perform the safety duties of this post, and comply with the relevant safety regulations of the site.
The pumped concrete should meet the permeability requirements of the concrete pump truck; concrete pump truck pumping work points can refer to the use of concrete pumps. When the concrete used has admixtures, the personnel who mix the admixtures must operate carefully and prevent injuries. Before the concrete pump truck works, the pump truck site and the substantial construction bin must have a perfect means of communication so that the construction is carried out safely.
In addition, the concrete pump should comply with the rules of use and operation, pipeline joints and safety valves must be intact, the shelf of the pipeline must be solid and disconnected from the structural formwork of the pumping part to form a self-supporting system, test delivery with water before delivery, pressure must be removed during overhaul, and test delivery must be made after overhaul.
The maximum tilt angle allowed when the whole machine is placed horizontally is 3°; a larger horizontal tilt angle will overload the steering gear of the fabric and endanger the stability of the device. In addition, if one of the legs or several legs of the fabric pole ever leaves the ground when moving, the legs must be reset until all the legs can always be reliably supported on the floor.
To ensure the fabric pole pumping work is in the best condition, should do: lift 1 section arm 45°; turn the fabric pole 180°; stretch 2 section arm 90°; stretch 3, 4, 5 section arm and be in a horizontal position. If the last fabric pole can be flat, it is ideal for pumping. However, suppose this section of the fabric rod is horizontal. In that case, the concrete flow will be slowed down, reducing the wear and tear of the conveying pipe and the end hose. As a result, only the concrete in the end hose will flow out when the pumping stops.
On the other hand, suppose the last fabric rod is tilted downward. In that case, the concrete in this part of the conveying pipe will accelerate the flow under the action of self-weight. As a result, the concrete in the conveying line will continue to flow out when the pumping stops.
When the pumping stops for more than 5min, the concrete in the end hose must be discharged. Otherwise, due to dehydration of the concrete in the end hose, the concrete will be violently ejected when pumping again, spattering in all directions, so the end hose is easily damaged. To change the position of the boom or concrete pump and need to fold, extend or retract the fabric rod, you should counter-pump 1 to 2 times before action so that you can place the concrete falling or spraying in the conveying pipe during activity.
During the operation of the pump truck, dedicated personnel should be arranged to frequently inspect whether there is any loosening of the conduit at various places and deal with it at any time, and to check the stable condition of the pipe fixing row frame and bracket, and whether there is any noticeable damage to the conduit, etc. Before taking over the use of the concrete conveying pump, the conveying pipe must be carefully inspected. If there are cracks in the pipe wall, wear and tear, severe wear of the pipe body, damaged joints, etc., it should be repaired or stopped to prevent accidents from occurring under more significant pressure when the concrete is being pressed.
The erection must be reliable and firm when the pump pipe is connected. A steel pipe row frame must be erected when suspended across, and to prevent the pumping process from swinging, anchoring steel reinforcement can be used. Concrete pumping pipe connection must use intact special card bolt, construction should be spare card bolt and wearable accessories.
When pumping concrete, no one should stand within 1 meter on either side of the conduit to prevent the line from swinging and injuring people; no one should stand within 30 meters directly in front of the conduit discharge port to prevent air from being pumped and the aggregate from being pumped at high pressure from injuring people. When installing and removing the conduit against the wall, workers must comply with the safety requirements for height and fasten the safety belt (rope); the line must be firmly connected to the wall after installation to prevent tipping.
Installation, removal of the pump pipe, labor should be sufficient, not hard to install, hard to remove the line; concrete delivery needs to be pressed when the pump is sent, pressurized water plug should be quickly and accurately connected to the firm, the warehouse personnel should pay attention to the outlet spray water washdown construction personnel.
Conduit removal shall not arbitrarily remove one of the sections, should comply with the top-down, previously and after the principle, the removal of the conduit shall not be thrown directly from a high throw; conduit removal must be put on a level site, not randomly stacked on the row of shelves.
After dismantling the pipe, it must be lifted to a level site and rinsed clean, stacked smoothly, and inspected, and any damage must be repaired in time. The parking site of the concrete pump truck must be hardened, parked smoothly and firmly, and have good drainage facilities to prevent collapse.
Nowadays, concrete pump truck has been widely used in concrete casting construction. The advanced technology of this equipment and the complexity of maintenance determine the high requirements for its use, maintenance, and management personnel. To ensure that the concrete pump truck in work can reach the specified technical state, reduce maintenance costs, improve the reliability and life of its use, it is necessary to carefully implement the maintenance procedures. To ensure the safety of the concrete pump truck operation and avoid causing personal or equipment accidents, the following safe operating systems must be strictly observed.
Concrete pump truck should meet the following requirements to complete the pumping operation: concrete pump should be placed on flat, solid ground, the site as far as possible away from high-voltage lines and other obstacles, after putting down the legs and adjustment, the body should be kept horizontal and stable, the tires should be wedge tight.
Horizontal pumping pipeline should be laid in a straight line; vertical pumping pipeline should not be directly connected to the output port of the pump, should be installed in the front of the vertical pipe with a length of not less than 20m horizontal pipe, and in the horizontal line near the pump with a check valve; when laying downward sloping pipeline, a horizontal pipe should be installed on the output port, and its length should not be less than 5 times the difference between the height of the sloping line.
When the inclination is significant, an exhaust valve should be installed at the upper end of the slope; the pumping pipe should be supported and fixed, and a wooden cushion should be set between the line and the selected object for buffering, and should not be directly connected with the steel bar or template, and the pipe should be firmly joined with the tube; the pipe joints and clamps should be firmly sealed and should not leak; the worn line should not be installed in the high-pressure area at the back end; after the pumping pipe is laid, a pressure resistance test should be conducted.
Sand and gravel grain size, cement grade, and ratio should be according to the factory regulations and meet the pumping machine’s permeability requirements. Before the operation, check and confirm that all bolts of the pump are tightened, suitable pumping parts are selected, guards are complete and reliable, manipulation switches, adjustment handles, handwheels, control rods, and plugs are in the correct position, hydraulic system is regular without leakage, hydraulic oil is by regulations, mixing hopper is free of debris. The protective grid above is intact and tightly covered.
The wall thickness of the conveying pipeline should match the pumping pressure, and high-quality pipes should be used near the pump. Pipeline joints, seals, and elbows should be intact. A wet sack or straw bag should cover the pipeline under high temperatures and hot sun. Water should be poured in time to cool down the temperature, and insulation measures should be taken in the cold season. Should be equipped with cleaning pipe, cleaning supplies, ball catcher, and related devices. Before turning on the pump, irrelevant personnel should leave around the pipeline.
Check before operation: The power switch of the operation console should be in the “off” position; the concrete displacement handle and the mixing device reversing grip should be in the middle class. The concrete pump truck should be placed horizontally, and the supporting ground should be flat and solid to ensure that it does not sink during work. The legs can support the whole machine stably and reliably and locked reliably.
When the boom is extended or retracted from the folded state, it must be done by the prescribed order. The slewing operation of the crash must be carried out after the boom has wholly left the boom bracket. The jib must not be used in a stormy condition or when the wind reaches level 8 or more (wind speed 16-17m/s). The jib should never be used for lifting operations.
After starting, it should run with no load, observe the indication value of each meter, check the operation of the pump and mixing device, and confirm everything is expected before the procedure. Before pumping, add 10L of water and 0.3m3 of cement mortar to the hopper to lubricate the pump and pipeline.
During the pumping operation, the concrete plane in the hopper should be kept above the axis of the mixing shaft. The hopper grid should not be filled with concrete, the flow of material supply should be controlled, the super-grain size aggregate and foreign matter should be removed in time, and the grid should not be moved at will.
When the concrete entering the hopper is segregated, the pump should be stopped and pumped again after mixing evenly. When the aggregate separation is severe, and the mortar in the hopper is obviously insufficient, part of the aggregate should be removed, and the mortar should be added and remixed.
When pumping operation starts or stops, contact the operator at the end hose; the bending radius of the end hose should not be less than 1m, and no bending is allowed; before dismantling the blocked pipe, the pump should be counter-pumped 2 to 3 times to confirm that there is no residual pressure in the line before dismantling.
Pumping concrete should be a continuous operation; when forced to suspend due to interruption of material supply, the stopping time should not exceed 30min. The suspension time should be every 5~10min (3~5min in winter) for 2~3 anti-pump – positive pumping movement strokes. The material should be mixed before feeding and pumping again.
When the pump stopping time exceeds the limit, the pipeline should be emptied. After an interruption of vertical upward pumping, reverse pushing should be made first when pumping again. The concrete in the distribution valve is sucked back to the hopper and then pumped positively after mixing. When the pump is running, it is strictly forbidden to put hands or shovel into the hopper or grasp the distribution valve by hand. When working on the hopper or distribution valve, turn off the motor and eliminate the accumulator pressure first.
Do not adjust the hydraulic system pressure at will. When the oil temperature exceeds 70℃, the pumping should be stopped, but the mixing blade and fan should still be made to run and then continue to run after cooling down. The water tank should be full of freshwater. When the water is cloudy, and there are more sand particles, it should be checked and processed in time.
When pumping, do not open any conveying and hydraulic pipelines; do not adjust or repair the parts in operation. During operation, the pumping equipment and channel should be observed. Any hidden problems found should be dealt with in time. The pipes, clamps, seals, etc., that are worn out beyond the regulations should be replaced in time.
The pipeline should be prevented from clogging, the pumped concrete should be mixed evenly, and the slump should be controlled; in the process of pumping, the pump should not be stopped midway. When there is a blockage in the delivery pipe, it should be a reverse pumping operation to make the concrete return to the hopper; when the reverse pumping several times still can not eliminate the blockage, it should be unloaded in the pump machine, remove the pipe to exclude the backup.
After the operation, all the concrete in the hopper and in the pipe should be output, and then the pump, hopper, and tube should be flushed. The air inlet valve should not be opened wide immediately when washing the line with compressed air. Only when the concrete is discharged smoothly, the air inlet valve should be extended to the maximum.
No one should be allowed to stand within 10m in front of the outlet end of the pipe, and metal mesh baskets, etc., should be used to collect the washed-out cleaning balls and grains of sand and gravel. For solidified concrete, scrapers should be used to remove. After the operation, the piston on both sides should be turned to the cleaning room position and coated with lubricant.
All parts of the manipulation switch, adjusting handle, handwheel, control rod, plug, etc., should be reset. The hydraulic system should be unloaded.
The boom should be wholly retracted on the boom support after operation; the legs should be completely rejected and inserted into the locking pin. The power switch of the operating table should be in the “off” position. The accumulator can only be filled with nitrogen gas, not oxygen, hydrogen, and other flammable and explosive gases.
There are a series of emergency shutdown buttons on the concrete pump, which are set on the outrigger control valve, wired and wireless remote control system, and the control box, so in case of emergency, you only need to press one of the emergency shutdown buttons to shut down the machine. If the emergency shutdown button is faulty, the device cannot be shut down quickly in sudden danger. Therefore, the function of the emergency shutdown button must be checked before each start of work.
When the emergency shutdown button is pressed, the electric system of the machine is cut off, causing the solenoid valve, etc., to close. If the hydraulic system produces leakage, it will cause the failure phenomenon such as the sinking of the fabric pole. This situation cannot be solved by pressing the emergency shutdown button.
Concrete pump truck in the construction of the use of some common failure phenomenon, to effectively prevent and check, first of all, we must clearly understand the elemental composition and structure of the equipment, especially the design of the hydraulic system, working characteristics and working principle, because, in the concrete pump truck failure, the hydraulic system problems account for a considerable proportion.
In the analysis of these failures, it is necessary to start from its fundamental principles to accurately determine the loss of its ability to work or the cause of a failure, and further confirm that the design and manufacturing defects brought about by the problem or the installation and use of improper issues. Only know the working principle to make the correct judgment; otherwise, troubleshooting with certain blindness, the wrong diagnosis will undoubtedly cause high repair costs, extended downtime, and further lead to low productivity and a series of adverse consequences.
Therefore, analyzing the causes of failure of concrete pump trucks can help us in the concrete pump truck maintenance, find the right direction, solve the problem, improve the efficiency of care, reduce the time consumed by maintenance.
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