Concrete pumping plant, stationary or mounted on a chassis truck, greatly simplifies the time-consuming task of delivery concrete mortar to the work area at the construction site. And when monolithic construction There is no other way to effectively lift ready-mixed concrete to a great height other than using a concrete pump.
For successful operation of a concrete pump on a construction site, it is necessary to ensure a number of conditions, which will be discussed below.
First of all, convenient access to the work site. Concrete pumps, both automotive and stationary, differ large sizes, their transportation and installation on site requires sufficient space to allow maneuvering.
Please note that the wheelbase equipped with some models of stationary pumps is only used for maneuvering on a construction site, and not for transportation along road routes.
Requirements for the installation site of the concrete pump
A platform with a durable and even surface is required. For stationary concrete pumping plants, a free space of at least 6 m in length and 3 m in width will be required. more space to set up hydraulic supports, so the minimum length of the platform for it is 10 m and width 6 m. dimensions concrete pump depend on its power and, accordingly, the length of the boom - the higher these indicators, the larger the area it will occupy this installation. In addition to the concrete pump site itself, it is important to ensure free access for concrete mixer trucks to its bunker.
A concrete pump requires water to operate. Its accessibility is ensured using a hose led from the water source to the concrete pump position, or by installing a container with 2 m 3 of water. In the cold season (down to -20 o C) to ensure the operation of concrete pumping unit you will need hot water in equal volume.
Stationary concrete pump with electric motor needs to be connected to a power source and a compressor unit that develops air pressure at 3 atmospheres.
Putting the concrete pump into operation
First, cement laitance is pumped, it is necessary to lubricate the concrete pipeline channel. Preliminary lubrication of the concrete pipeline with a starting mixture will reduce the likelihood of plugs forming inside it at the stage of equipment startup. Cement laitance in a volume of 2 m 3 is purchased from a ready-mixed concrete supplier, or the concrete pump operator will make the starting mixture himself if he is provided with 100 kg of cement and a source of water (this option will be cheaper).
Certain characteristics of concrete mortar. Minimum conditions:
· mobility established by cone draft - more than 160 mm;
· grade of ready-mixed concrete - not lower than M-300;
· filler grain no larger than 40 mm.
Otherwise, the supply of concrete by a concrete pump will either not be possible at all, or will occur with frequent failures.
Setting up the concrete pump and preparing it for work will take about half an hour. If the concrete pipeline is expanded with additional sections, then more time will be required for preparation.
Cleaning the concrete pump and concrete pipeline
At the end of the work shift, the concrete pump must be washed and its boom (concrete pipe) removed - this operation takes approximately 40 minutes. Leftovers concrete mixture, washed out of the bunker and concrete pipeline (boom) of the pumping unit are disposed of at the construction site. To collect the remaining concrete, you need to make a formwork box, the length and width of which will be 2 m, the height of the side will be 400 mm. There is no need to arrange the bottom - the concrete mass will be held by a single-layer pre-walled inside the box PVC film(polyethylene thickness 150-200 microns).
Upon completion of washing the concrete pump, the concrete collected in the formwork box is transferred to the disposal site - the edges of the polyethylene are pulled together to form a bag, inside which the concrete is held.
To clean the system from concrete residues you will need:
1) warm water(200 l for several cleaning cycles);
2) air compressor;
3) a flushing unit designed to supply water or compressed air (at a pressure of no more than 10 bar);
4) flushing balls and wads in the form of a cylinder, which are made of sponge material to match the diameter of the concrete pipe.
Cleaning the concrete pipeline should be carried out immediately upon completion of the delivery of the last batch of concrete, having prepared everything necessary for this before the last automixer is emptied. It is important to constantly maintain contact with the operator at the concreting site - he must inform you when only the volume of mixture currently contained in the system remains to be poured. After such a signal, you need to stop supplying concrete and pour water into the concrete pump hopper - the resulting liquid mixture is maintained in the hopper at as low a level as possible, but not so much that air gets into the piston cylinders (the entry of air will lead to a problem - it will stratify the mixture). Having completed the pouring, the operator of the concreting site gives a signal to the concrete pump operator - he switches the operation of the concrete pump to reverse (reverse mode) to reduce the amount of mixture in that part of the concrete pipeline that is located closer to the work site and to reduce the pressure in the concrete pipeline. The concrete pipeline is then disconnected from the pump and extended with additional sections to reach the area intended for discharging the contents of the concrete pipeline (they must be prepared and assembled to the required length in advance). Be sure to put a catcher attachment for the flushing ball on the end pipe leading the concrete pipe to the discharge site - it can fly out at a decent speed. The operator of the concreting site removes the dispensing hose from its end of the concrete pipeline and installs a blowing nozzle instead of the last elbow, having previously inserted a flushing ball into the concrete pipeline with plenty of water moistened (it is better to combine it - first insert the ball, followed by the wad). The launch of compressed air by the operator of the concreting site and the movement of the needle valve fingers to the “open” position must be performed as synchronously as possible - the movement of the flushing ball along the concrete pipeline should not stop for a minute. It is better to carry out the washing operation twice - you need to re-supply water to the concrete pipeline through the concrete pump, switching the needle valve to the “closed” position. The concrete pump hopper is washed and cleaned with a stand under the outlet of the drain tray. It is especially convenient if this model is equipped with its own water pump with a hose and a container for water heated by hot gases from the exhaust pipe - it is easier to wash and remove the remaining concrete mixture, because no need to think about where to get hot water.
Disposal of remaining concrete
Where should I dump the remaining concrete after flushing the system? You can’t just throw it on the ground - this will seriously damage the soil, because the semi-liquid material will spill over the construction site. There are two options:
1) collecting washing residues in a box;
2) dumping the penultimate automixer into the bunker, having previously agreed on this operation with the concrete supplier.
In the first option, you need to assemble a square formwork box from boards (height 2,000 mm, depth 500 mm), lining it with PVC film 200 microns thick - after washing, its contents can be moved for disposal. The second option: lead the discharge hose from the concrete pipe into the hopper of the automixer, run it in the “loading” direction and secure it with a chain (otherwise it will jump out and splash everything), then begin the washing process described above.
Flushing, bleeding or cleaning are synonyms that describe the most important part daily maintenance of the concrete pump. This procedure must be completed at the beginning and end of each shift. Just before starting work, pump the starting or starter mixture. And after completing the shift, the concrete pipeline of the pumping unit is washed with water and blown with compressed air. If any of these operations are missed, the concrete pump of any model or brand becomes unsuitable for further operation and may fail.
If you feed the concrete mixture into an unprepared, dry concrete pipeline, you can get a blockage of the entire supply line or separate partial plugs of concrete adhering to the walls. It is recommended to use a homemade or purchased starting mixture, which can be prepared directly at the construction site (a bag of dry powder dissolved in hot water) or brought with an automixer from a concrete plant (cement laitance). If you use a mixture of 150 kg of cement and 200 liters of water, mixed with your own hands in the concrete pump hopper, then it is necessary to obtain a solution of the same type as the concrete that is then pumped.
It is advisable that the pumping of the starting mixture be used simultaneously with the flushing kit (balls and wad). They are also needed for flushing the concrete pump after the end of the shift. The ball is a dense cylindrical sponge of the same diameter as the concrete pipe. The sponge is pre-placed in the starting solution to maximize wettability. inner surface concrete pipeline The more evenly the cement laitance is distributed throughout the pipe, the less likely it is that the concrete will stick during the transfer process. When starting the flushing kit with the mixture, the needle valve fingers should be in the “open” mode, and after the operation is completed, they should be in the “closed” state.
Next, concrete is immediately supplied, and throughout the entire shift, the hopper and concrete duct of the pump must be filled with solution to avoid the formation air jams. If there are any problems with the feed from the mixer, the operator must constantly switch between direct and reverse pumping modes, while the solution in the hopper must be constantly mixed to prevent separation. If the downtime exceeds half an hour, it is recommended to completely clean the pump unit, as at the end of work. After completing the shift, approximately 0.7 m3 of solution remains in the concrete pump, which must be removed immediately.
To flush the concrete pump you need about half an hour and 1-2 m3 hot water, which must be supplied using a hose that can withstand water/air supply under pressure up to 10 MPa. The easiest way to clean those models is that they include a hose, a water pump and a container heated by the exhaust gases of the concrete pump. Everything must be prepared before the end of the supply of the solution to the concreting site, especially at very high or low temperatures environment when the mixture in the concrete pump hardens almost instantly. After a warning signal from the operator responsible for placing the concrete, water is added to the hopper. This mixture requires little, but it should cover the pistons so that no air gets into the cylinders. At this time, the last volume of the mixture arrives at the concreting site, pouring stops, and the concrete pump switches to reverse suction. At the same time, the pressure decreases, and the remaining concrete is returned back to the bunker and mixed with the aqueous solution. The concrete pipeline is disconnected from the concrete pump, which is supplemented with several sections, and a special nozzle (ball catcher) is installed on the last elbow. It is better not to refuse it, because during the blowing process the balls fly out of the concrete pipe at high speed and can end up at a distance of up to 200 m from the concrete pump. The further away the place for discharging the remaining mixture is, the longer such a pipeline will be. There are several ways to get rid of unnecessary concrete. The cheapest is to simply pour it on the ground, but this harms the soil and may prevent further construction work. It is preferable to pour the solution into a specially made box (2x2x0.4 m), lined with PVC film 150-200 microns thick, or into the hopper of an empty automixer, having previously agreed on this issue with its owner.
After preparing to release the mixture, the operator removes the dispensing hose from the end of the concrete pipeline, replacing it with a blowing nozzle. A flushing kit (well-moistened sponge balls and a wad) is inserted into the concrete pipeline. In the same way as when supplying the starting mixture, the fingers of the needle valve are switched to the “open” mode, and after flushing is completed, they are switched to the “closed” state. At the same time, it is served compressed air. This is how it is possible to ensure continuous movement of the ball through the pipe. It is advisable to repeat the operation by supplying water to the concrete pipeline. Afterwards, all that remains is to rinse the bunker, and the concrete pump is ready for further operation.
One of the most important stages service of a concrete pump is its regular cleaning, which must be carried out daily before starting work and upon completion. Before starting active work, it is necessary to rinse the mechanism with a starting solution, and then treat it with water and compressed air. Flushing the concrete pump in this order is necessary to maintain the equipment’s suitability for everyday and uninterrupted operation. The slightest omission can cause failure important details and the mechanisms of the unit. If your profile is renting a concrete pump, the quality of functioning of the copies provided to clients must be impeccable.
Why is daily maintenance performed?
If the mixture is fed without preparation into a concrete pipeline with a dry coating, the risk of clogging the supply line and the appearance of plugs from the solution increases, which can stick to the walls of the container. The starting mixture used for cleaning can be specialized and purchased from specialized companies or homemade. The concrete pump is flushed using the following resources:
- 200 liters of water for several stages of cleaning;
- Air compressor;
- A flushing unit capable of operating at a pressure not exceeding 10 bar;
- Wadding wads made from a cylindrical or spherical sponge, the size of which will correspond to the diameter of the concrete pipe.
The concrete pump must be cleaned immediately after the final batch of concrete has been unloaded from it. At the same time, everything necessary materials for cleaning must be prepared in advance before the container is emptied. The operator located at the site where the concrete is being poured must monitor the supply of the last batch in order to immediately begin the flushing procedure.
Algorithm for cleaning a concrete pump
The launch of the starting mixture into the functional volume of the pump should be carried out using a wad and a ball, which are also necessary at the end of the work. Tools made of sponge material are easily dipped into the container and pre-wetted with a starting mixture to make the cleaning process more effective. The uniform distribution of the composition ensures that the adhering composition is washed off from the walls of the concrete pump. When the flushing kit is run into the unit, the needle valve pins must be opened and closed after servicing is completed.
Immediately after such treatment, the container is filled with a solution that remains in its volume throughout the entire shift in order to avoid the appearance of air plugs. If the operator notices delays and malfunctions, it is necessary to use reverse pumping and direct operation so that the concrete mass does not delaminate and is constantly mixed. If the concrete pump has been at rest for more than thirty minutes, it is necessary to clean it using the same algorithm as at the beginning or end of the shift.
The procedures are carried out for half an hour using up to two cubes of hot water, which is directed into the container through a hose that is resistant to pressure of no more than 10 MPa. Water can be heated using exhaust gases produced by the pump. Quick preparation must be organized with special care, especially if the ambient temperature constantly fluctuates, low or excessively high, such as during drought or frost.
Concrete pumps are cleaned after the operator's command. Water is poured into the hopper up to the level of the pistons to prevent air from entering the cylinders. At this time, the final part of the solution is supplied to the treated area. Upon completion of filling, the reverse mode is activated. The pressure is reduced, the remaining composition is mixed with water in the hopper, the balls are launched and the container is cleaned by blowing.
The mixture obtained during cleaning is drained, a washing kit is introduced into the concrete pipeline and compressed air is supplied, which creates the necessary conditions for continuous movement of the sponge in the concrete pipe. Then the procedure is repeated using water and finally the usual rinsing is carried out, after which the unit is again ready for high-quality operation.
How to get rid of leftover concrete mixture?
Concrete mortar has specific physical and chemical properties, therefore, volumes of material unsuitable for further use must be eliminated by taking care of the dump site in advance. When cleaning concrete pumps, you cannot simply dump the mass on the ground, so you will need special collection boxes or the use of one of the automixers.
In the first case, suitable containers are needed, the height of which will be at least 2 meters and the depth - half a meter. A kind of formwork is lined with PVC film and all residues washed out during cleaning can be easily transported for disposal.
The second option involves using a hose and a hopper into which the remaining mixture is immersed, followed by starting in the “loading” mode, after which washing begins.
Cleaning a concrete pump is an important procedure that directly affects the quality of operation of the equipment, so you should prepare for it in advance, having thought through all the nuances and preparing the necessary consumables.
