Nowadays, automation of the construction process is increasingly being introduced into construction industry, which allows you to reduce the cost of the facility being built, increase the speed of construction and make the work of builders easier.

One of the construction automation processes is usage concrete pumps, photo 1.

Photo 1. Concrete pumps on a car chassis

A concrete pump is a set of equipment that is installed on a truck chassis and consists of the following main parts:

• built-in folding concrete pipeline in the form of an arrow (boom-concrete pipeline). The length of the concrete pipeline in working position can be 22…64 m, photo 2;
• rubberized hose (“trunk”, usually about 4 m long);
• mixer;
• loading hopper;
• concrete elbow (there are 3...7 pieces);
• hydraulic cylinder (usually 2 pcs);
• water pump;
• concrete castle with rubber seal;
• flushing device.

Photo 2. Concrete pump-boom concrete pump in working position

There are truck-mounted concrete pumps with the following boom reach: 22 m; 32 m; 36 m; 42 m; 46 m; 52 m; 53 m; 57 m.

Depending on the type of supply, concrete pumps are divided into:

• vacuum (concrete is supplied by creating a vacuum in the system);
• piston (concrete is supplied due to the movement of pistons);
• curtain (presence of curtains);
• gate (presence of gates).

The shape of the concrete pipeline is:

• S-shaped concrete pumps;
• C-shaped concrete pumps.

There are concrete pumps different types depending on size and method of transportation:

• stationary (has wheels for movement and is made in the form of a trailer);
• automobile (based on a truck);
• mini concrete pump (used for small volumes of concrete or small supply), photo 3.

Photo. 3. Types of concrete pumps: a) stationary; b) mini concrete pumps

On photo 4 truck-mounted concrete pumps with high performance and long boom length are presented.

Photo 4. Concrete pumps with maximum power and long boom length. Installation of concrete pumps manufactured by Putzmeister M70-5 (Germany) and CIFA K80H Carbotech on cars of the brands Kenworth C 500B, Mercedes, Man

An automobile concrete pump has a number of advantages, such as mobility and the possibility of more convenient maintenance of the entire machine as a whole. But, for example, a stationary one is cheaper in terms of rental and operating costs.

Conditions under which the concrete pump is used

1. The main purpose of a concrete pump is to pump concrete from concrete mixers () to the concreting object, which is located in a place that is difficult to access.
2. When using the appropriate concrete mixture. For normal operation of the concrete pump, a concrete mixture with a maximum crushed stone size not exceeding 1/3 of the cross-section of the concrete pipeline should be used. Typically, for concreting most construction projects using a concrete pump, a concrete mixture with a crushed stone size in the range of 20...60 mm is used, while inner diameter concrete pipe should be 60...120 mm.
3. If necessary, concrete building elements and structures at a significant height, more than 5 m.
4. If necessary, concrete the entire structure at once.
5. For large volumes of concreting, when it is necessary to concrete with high productivity and for a long time, with the possibility of round-the-clock operation of the concrete pump.
6. Characteristics of the concrete mixture for which a concrete pump can be used:

• mobility of concrete mixture P4, P5 (cone slump 16...21 cm);
• W/C (water-cement ratio) not more than 0.75;
• strength grade is not less than B12.5 (M150), for some pumps - not less than B22.5 (M300).

Operating principle of a concrete pump

The principle of operation of the concrete pump is that the concrete mixture is supplied continuously from the concrete mixers at a certain speed into the concrete pump hopper. From the bunker, with the help of pumps, the concrete mixture enters the concrete pipeline, from where it goes to the direct concreting site.

Before operating the concrete pump, to create a thin lubricating layer that ensures easy pumping of concrete, you should pump a small amount of the following mixtures to choose from:

• mortar;
• cement-sand mortar in a ratio of 1:2 (C:P).

It is not permissible to take long breaks in the supply of concrete, more than 15...20 minutes. In the event of an emergency or forced stop of the concrete pump for more than 1 hour, if possible, you should pump a minimum amount of concrete every 10 minutes at low speed so that it does not set inside the concrete pipeline.

IN winter time The condition for the operation of the concrete pump is pumping the concrete mixture at a temperature not lower than 25...30°C, i.e. it needs to be preheated. During winter concreting, concrete pipes are additionally insulated.

Application of a route

In particularly difficult conditions, where the access to the facility is very far or high, it is used optional equipment– routes (set of concrete pipes). The route consists of a certain number metal pipelines, which are laid to the object along the shortest path with a minimum number of bends.

Concrete pipes cannot be installed at right angles or strictly vertically; in extreme cases, if the length of the concrete pipe is short, placement at a right angle is allowed if this bend is located no closer than 8 m from the concrete pump itself and there is provision for additional installation needle valve.

When choosing to rent a concrete pump, you should pay attention to its characteristics:

• type of concrete pump;
• power and performance of the concrete pump;
• concrete mix supply parameters ( maximum length and height);
• concrete pump manufacturer.

Advantages of using concrete pumps

1. Possible direct access to the construction site in difficult conditions, when it is not possible for a concrete mixer truck to drive directly to the construction site.
2. Labor costs are reduced.
3. The loss of concrete during transportation to the formwork is reduced.
4. The speed of construction increases.
5. High durability of concrete pump equipment when used correctly.
6. The concrete pump equipment is easy to operate.
7. Possibility of supplying concrete in horizontal and vertical directions:

• horizontally – up to 300 m;
• vertically (height) – up to 80 m.

1. The mobility of the installation allows for maximum use of equipment in terms of time and speed of movement.
2. High productivity (up to 90 m³/h).
3. Convenient to use in monolithic construction of multi-story and massive buildings and structures.
4. Concrete pumps can be powered by an electric or diesel engine.

It is believed that the concrete pumps from the manufacturers listed below have more high quality and reliability:

• Putzmeister (Germany);
• Cifa (Italy);
• Sany (China).

Konev Alexander Anatolievich

Malyavin Anatoly Nikolaevich

Concrete pumps are a device for pumping concrete that is mounted on a truck chassis. This equipment is designed to receive freshly prepared concrete mixtures from special concrete transport vehicles and deliver it in vertical or horizontal directions to the placement site.

The technique is used in the construction of mines, bridges, buildings and various structures from monolithic concrete.

Concrete pumps can be of two types - piston and rotary.

An important component of the equipment is the concrete distribution boom, on which concrete pipes are installed. The boom consists of several movable elbows, through which folding, movement, etc. are controlled. The boom length is 22-64 meters. But on some Japanese or Korean-made models, which are characterized by their small size, the boom length can be 10 meters. At the base of the boom is placed directly pumping unit, as well as a receiving hopper for concrete. A flexible hose-trunk 4-8 ​​meters long is attached to the end of the boom. Truck-mounted concrete pumps operate in the following way: concrete or mortar flows from the concrete mixer tray into the receiving hopper of the truck-mounted concrete pump. Next, the pumping unit pumps the mixture directly to the unloading point (which can be located high or horizontal). By the way, mortar and concrete can be supplied both along the boom of concrete pumps and along a route that is installed on site using separate pipes connected by special clamps. A rubber trunk is placed at the end of this route, which distributes the concrete over the formwork. The length of the trunk is on average 4 meters.

As a rule, the route is used when pouring in existing buildings or under power lines, as well as in cases where it is difficult and impossible to bring the boom of a concrete pump to the required location.

The equipment can be controlled using a radio remote control or a backup remote control with cable.

Truck-mounted concrete pumps are equipped with hydraulic drives.

The distribution system can be with a standard gate or with an S-shaped gate.

According to the type of concrete supply, the equipment can be vacuum (concrete is forced through the creation of a vacuum in the tray) and piston (concrete passes through the system due to the action of one or two pistons).

Curtain concrete pumps are designed in such a way that the feed mechanism is separated from the concrete pipeline by curtains. In gate installations, the feed mechanism is separated from the concrete pipeline by a gate unit.

The world record for conveying concrete horizontally is more than two kilometers. The record height of concrete delivery is 715 meters, which was achieved during the construction of the Parbati hydroelectric power station in India in August 2009 using a pump manufactured by Schwing Stetter. In addition, the height of the tallest building in the world, the entire volume of concrete for which was laid with one concrete pump, is 302 meters.

For the construction of a small facility, it is not always rational to use large-sized special equipment. Great solution The task at hand will be the use of mini concrete pump technology, which has similar parameters to the performance characteristics of large specialized equipment for construction. The small-sized concrete pump has proven itself in monolithic construction, which requires a quick solution for pouring foundations and other load-bearing structures buildings.

Why choose mini equipment?

Buying a large stationary or mobile concrete pump does not always pay off. Expensive equipment can take months or years to pay for itself, while you need to solve production problems. A mini concrete pump can be rented, and if funds allow, purchased on lease or through another credit program. In the construction segment, there are universal tasks where it is necessary to fill structures without the use of large equipment, and at the same time it is irrational to use homemade concrete pumps. Low price special equipment with a full daily load will allow you to pay for yourself in about 6-8 months, and renting a mini concrete pump can “recoup” the investment even faster, but again, subject to a full daily load.

The market for small concrete pumps is quite extensive, there are Russian developments, but in Lately can be seen on construction sites mini-equipment made in Japan, China, USA, South Korea, as well as a number of industrial developed countries. For low-rise construction, where there is an average level of duty cycle, only a mini stationary concrete pump is the best solution organizing the work cycle process at the production site.

Technical characteristics of mini-special equipment

To properly organize the work cycle of a job where pouring concrete mixture is required, try renting a miniature concrete pump. Approximate specifications Special equipment includes:

• The maximum supply size of a hose with mortar is 150 meters.
• The maximum level of solution supply to a height is 50 meters.
• Basic installation - electric or diesel engine general principle actions.
• Fully autonomous mode of movement.

Options for small concrete pumps

Before you learn correctly how to choose a concrete pump for construction work, we suggest you familiarize yourself with the groups of special equipment. There are two types of specialized equipment on the market, which are represented by the following categories.

• Piston type. The most popular version of the concrete pump group, which is used not only in the post-Soviet space, but also in highly developed countries. Thanks to the universal principle of the piston group, it is possible to organize a continuous cycle of supplying concrete mixture to the production site. The maximum level of performance of a concrete pump m 3 depends on the technological chain of organizing the supply of solution by piston group machines. Installation of piston category equipment occurs on a mobile chassis or on self-propelled equipment.
• Rotor system. This type of mini concrete pump is also used in a number of technological processes. Due to the presence of a sleeve with rollers, direct ejection of the solution in portioned parts is ensured. The delivery system bypasses the concrete pipe and goes directly into the hose. The productivity of such equipment is 2-3 times less than in a piston group, but is effective for highly specialized work of supplying concrete mixture to a construction site.

"General dimensions of the concrete pump miniature shape allow the installation of a bunker for receiving and processing concrete mixture.”

Along with this in technological process it is necessary to fulfill strict time requirements for processing the mixture, which should not exceed 20 minutes, otherwise it will lead to the release of the main technological equipment out of service. Exceeding the processing time of concrete can cause premature wear of special equipment, therefore, upon completion of work, it is recommended to thoroughly rinse all components of special equipment with a strong stream of water or other technological liquid intended for cleaning the concrete pump.

Features of the selection of small-sized concrete pumps

Considering the high popularity of purchasing and renting small-sized concrete pumps, we note the main technical and functional advantages.

• Mobility. The equipment is capable of maneuvering through difficult streets and roads of a large metropolis, where the quality of concrete comes first, and, therefore, prompt delivery of the concrete pump to the site is guaranteed by the acceptable dimensions of the special equipment.
• Compactness. Considering limited space production site, the mini concrete pump is the right decision for the construction process. For example, in order for Kamaz to turn around completely, it is necessary to ensure free space 10*12 meters, for a miniature concrete pump, this space is 5*6 meters, that is, if you carry out construction processes inside a workshop, then a small-sized concrete pump can easily be deployed at your production site.
• Financial benefit. For large-sized equipment it is necessary to attract sufficient quantity auxiliary forces, on average up to 5-6 people. Mini concrete pumping equipment requires the use of 1 driver and a maximum of 2 auxiliary workers. The financial component is quite impressive.
• Multifunctionality. Using a concrete pump is not only about supplying concrete mixture. Some models of special equipment are equipped with a mixer, which allows you to mix concrete if it is not possible to invest in the time frame for pouring the solution during the production cycle.
• Performance. Despite its very miniature size, the special equipment has sufficient productivity. The maximum volume of concrete processing, depending on the machine model, is 70-170 m 3 . The maximum height of hose supply and equipment operation is up to 25 meters; some models of special equipment will allow you to lift the solution to a height of 50 meters vertically and about 160 meters horizontally.

Popular brands of mini concrete pumps

Additional information about special equipment

Considering that many equipment manufacturers have provided additional options machine control, it is necessary to carefully study the possibilities of using auxiliary technological equipment for supplying concrete mixture. The main weight of the installation equipment is about 1 ton, so it is possible to transport special equipment by light-duty transport if there is no mobile-type mobile scheme. Upon completion of work with concrete, it is necessary to thoroughly wash all units and components of special equipment to prevent the formation of concrete build-up after the mass has hardened.

Basic characteristics of a concrete pump is its power, on which the length of the arrow and the delivery range depend. The last parameter is highlighted separately, since the ABN is sometimes connected to a stationary highway intended for delivery to those areas where it cannot drive on its own. For modern construction machines are used whose boom reach can reach 64 meters - this is quite enough to build a multi-storey residential building. For the construction of monolithic structures whose height exceeds the indicated figure, use stationary systems combined with pipelines. The characteristics are quite varied and it is necessary to say a few words about how their selection should be made. First of all, there is a cost factor, which is the main limitation in the search process optimal model. The characteristics of a concrete pump must be selected in such a way that, with parameters sufficient for operation in specific conditions, it is possible to ensure that the rental or purchase price falls within the established range. It is worth understanding that when a product has insufficient parameters, the efficiency of its functioning under the given conditions of construction work is reduced many times over. If this is not taken into account, then a significant number of problems will arise that will have to be dealt with on site.

When choosing an ABN, the main attention is paid to its operational characteristics:

To use concrete pumps, several conditions must be met to ensure uninterrupted operation the unit itself and the safety of builders on site. The slope should not exceed 3%, otherwise operation may lead to an accident. For the same reason, it is not recommended to deploy the ABN near the fortified edge of the pit - minimum distance is 5 meters. Temperature limit environment is minus 15 degrees, in addition, there should be no power line wires near the object.

Transport machines

concrete mixture and mortars.

Concrete pumps and pneumatic blowers.

The method of delivering concrete and mortars from the mixing plant to the place of their placement and the equipment necessary for this is chosen depending on the nature of the structure, the total volume of the mixture to be laid, the daily need for the mixture, the height of its lifting and the distance of horizontal movement.

The range of supply of the mixture by concrete pumps through a horizontal concrete pipeline reaches 400 m, vertically - 70 m. By installing a series of concrete pumping units in series, it is possible to increase the delivery range and height.

With any method of transportation, the mixture must be protected from separating into its component parts.

In most cases, when performing large volumes of concrete work, it is economically feasible to transport the concrete mixture through pipes using concrete pumps. If it is necessary to transport concrete from central concrete installations to remote construction sites, the best vehicles to ensure the preservation of the quality of concrete are concrete mixers.

Fig.1. Concrete pumps in operation:

A - monolithic construction; b - construction of a wall, strengthening of a slope;

V – pouring the foundation; G – pouring floors.

In modern construction technologies, the most important role is played by increasing productivity, saving time, labor, and, ultimately, financial costs. The use of mechanized equipment allows us to solve this problem. One type of professional construction equipment is a concrete pump.

The purpose of this installation is to transport the prepared concrete mixture directly to the place of its pouring using a concrete pipeline, consisting of separate sections with quick-release connections and special distribution booms.

Supplying concrete through pipes during the construction of monolithic structures, compared to supplying it with belt conveyors or cranes, increases labor productivity and reduces the cost of work. This method of transporting concrete allows you to work in cramped conditions and hard-to-reach places where other types of supply cannot be used.

Concrete pump is a machine for injecting concrete mixture to the place of its laying (within the construction site) for the rapid and high-quality construction of various objects using a flexible concrete pipeline, which also makes it possible to inject concrete into various planes.

It is believed that supplying concrete using concrete pumps significantly improves the quality of the concrete being placed. This is explained by the fact that when transferring the concrete solution, additional mixing is carried out, which increases the structure of the concrete being laid.

Classification:

A). Structurally, depending on the purpose, concrete pumps

are divided into three main categories :

1) – truck-mounted concrete pump;

2) - stationary trailed concrete pump;

3) - truck-mounted concrete pump with mixer.

Fig.2. Concrete pumps:

A - stationary trailed concrete pump; b – concrete pump;

V - truck-mounted concrete pump with mixer (ABNS-29).

Concrete pumps- this is construction equipment designed to supply concrete to the place of placement, both horizontally and vertically. The concrete pump is installed on a vehicle chassis and consists of a dispensing boom, a support system and a concrete pump. Depending on the brand of concrete pump, the length of the concrete pump boom may vary up or down.

The productivity of a concrete pump can reach up to 200 m³/hour, and the concrete supply height is up to 48 meters. Some models of concrete pumps can rotate around a vertical axis or be equipped with mixers for mixing concrete. In general, the functionality of even the simplest concrete pump is quite sufficient for laying concrete over fairly large areas.

The operation of the concrete pump can be controlled either from the driver’s cab or from a remote control installed on the vehicle chassis. The operation of the concrete pump can also be controlled using a remote control. Such a remote control can transmit signals via radio or cable connected to the concrete pump.

The material is supplied from the concrete pump according to special pipe, which is called a concrete pipeline. The concrete pipeline is securely attached to the dispensing boom of the concrete pump, which completely eliminates the loss of material during delivery to the placement site. If laying concrete is planned to be carried out in winter, the concrete pipeline should be insulated or heated with steam.

Stationary concrete pump– special equipment, which is mainly intended for the construction of multi-story buildings. To supply the concrete mixture further, a boom (pipe) is installed on the concrete pump. Stationary concrete supply units (concrete pumps) are distinguished by the following technical characteristics: productivity from 15 before 85 m³/hour; supply of concrete mixture can be carried out up to 150 meters vertically, and up to 450 meters horizontally. The operation of stationary concrete pumps can be ensured by engines running on both diesel fuel and electricity.

They are intended for objects with a small volume of work and are lightweight mobile cars on wheels or skids.

Mobile mixers are used for small volumes of construction and repair work (with a small volume of mixing) at dispersed sites; they are lightweight mobile machines on wheels or skids; and stationary ones are part of the technological lines of concrete mortar mixing plants of medium and high productivity of concrete and mortar plants.

Stationary ones are more powerful, but do not have a boom for supplying concrete mixture.

B). By drive type:

■ crank;

■ hydraulic concrete pumps;

■ pneumatic concrete pumps.

IN). By number of cylinders:

■ single-cylinder;

■ two-cylinder.

G). By mobility:

■ stationary;

■ truck-mounted concrete pumps.

The most effective use of a concrete pump is in the following cases:

Increasing labor productivity in multi-storey construction

body;

Concreting areas where, for various reasons, it is difficult

concrete supply;

Concrete work at height;

There are obstacles preventing the access of the concrete mixer truck

The technological process of concrete pumps is as follows: concrete flows through concrete pipes to the place of placement. Distance and height may vary. The speed controller, depending on the characteristics of the concrete and the distance over which pumping is carried out, automatically sets the operating mode. Air temperature is also taken into account. The concrete is mixed using a reverse system.

The main advantages of concrete pumps: endurance and stability. Technical characteristics allow the equipment to operate in economical mode. Because equipment can be used all year round, including in winter, a diesel fuel heating system is installed on concrete pumps. To protect the engine from overheating, an oil cooling unit is installed.

Concrete pumps are easy to maintain. It is enough to use a flushing pump with a water gun.

General structure of concrete pumps

Piston type concrete pumps(with mechanical drive). The domestic industry produces piston-type concrete pumps with a capacity of 10, 20 and 40 m 3 /hour with mechanical and hydraulic drive.

Drive from internal combustion engine:

The principle of operation of the concrete pump is as follows: entering the receiving hopper 6 the concrete mixture is continuously mixed with paddles 5 , in order to maintain its homogeneity and prevent delamination. From the hopper mixture using a stimulant 7 , made in the idea of ​​a paddle mixer. Enters through suction valve 8 into the cylinder 11 pump

Piston 12 the pump performs a reciprocating movement using a crank mechanism, the crankshaft 2 which is driven into rotation by the main electric motor of the concrete pump. The movement of the piston is strictly coordinated with the position of the suction 8 and pressure 9 valves: during the suction movement of the piston (Fig. A) valve 8 opens and the valve 9 closes; with the piston in the discharge position (Fig. b) valve 8 closes and the valve 9 opens. Synchronization of the movements of the piston and valves is achieved using a rocker mechanism 1 , receiving rocking motion from profile cams on the crankshaft, and two rods 3 And 4 , connecting each of the scenes with the valves. During the suction movement of the piston, the concrete mixture enters the cylinder cavity, and during the discharge movement it is pushed into the pipeline 10 .

Fig.3. Mechanical driven concrete pump:

A - scheme of work; b- kinematic diagram; І – suction position of the piston; ІІ – discharge position of the piston;

1 – rocker mechanism; 2 – KShM crankshaft; 3 And 4 - traction; 5 - blades; 6 – receiving hopper; 7 - stimulant; 8 - ;suction valve; 9 – discharge valve; 10 - pipeline; 11 – pump cylinder; 12 – pump piston.

Electric motor drive :

Concrete pumps are mounted on a welded frame 15, equipped with skis 16 to be able to move the concrete pump over short distances. Receiving hopper 6 is made welded from sheet steel, and its inner surface lined with replaceable armor plates that protect the bunker walls from wear. An upper platform is attached to the bunker 20 on which the drive is mounted 3, 4 And 5 mixer shaft 7 and the ballast and control electrical equipment is attached 2 main drive. From this platform, the flow of concrete mixture into the bunker is monitored. In the lower transition funnel of the bunker. A shaft is installed in close proximity to the suction valve 8 motivator. The driver shaft is driven using a chain drive 21, 27 from the crankshaft 18 .

The working part of the concrete pump consists of a valve box 12 and cylinder 13 , in which the piston moves 17 . The inner surface of the valve box is lined ( lining – This is a special finish to ensure the protection of surfaces from possible mechanical or physical damage) with replaceable bushings made of wear-resistant steel, and the cylinder with an insert liner.

Fig.4. Concrete pump:

1 – main electric motor; 2 – ballast control equipment of the main drive;

3 ; 4 And 5 – mixer shaft drive; 6 – receiving hopper; 7 - mixer; 8 – exciter shaft; 9 – suction valve; 10 – discharge valve; 11 - ; 12 – valve box; 13 - cylinder; 14 – rubber tip; 15 – welded frame; 16 - skis; 17 - piston; 18 - crankshaft; 19 - traction; 2 0 – upper platform; 21 And 27 – chain transmission; 22 And 23 – profiled fists; 24 And 25 - backstage; 26 - connecting rod.

The cylinder liner wears out relatively quickly

Fig.5. Concrete pipe details:

A – set of links; 1 – straight link length 3 m; 2 – straight link 1.5 long m; 3 - straight link 0.9 long m; 4 – straight link 0.6 long m; 5 – straight link 0.3 long m; 6 – elbow at an angle of 90°; 7 – knee at an angle of 45°; 8 – elbow at an angle of 22°30"; 9 – elbow at an angle of 11°15";

b – lever lock connecting the concrete pipe links; 1 And 5 – concrete pipeline links; 2 - rotary lever; 3 – traction; 4 – clamp;

V – needle valve; 1 - lid; 2 – needles; 3 – needle holder.

Pneumatic concrete pumps. Designed to move portions of concrete through pipes using compressed air.

Fig.6. Pneumatic concrete pump:

A - general form; b- device diagram; 1 - pipeline; 2 - guide cone;

3 - funnel; 4 - cone shutter; 5 - storage tank; 6 - nozzles.

The feed range is within 150 m.

Concrete pump with hydraulic drive. Partially eliminates the disadvantages of a mechanical drive. They consist of a stimulator installed under the feed hopper 2 two working cylinders 4 , equipped with two slide gates - vertical 7 and horizontal 6 . The movement of the pistons of the working cylinders and gate valves is communicated by oil-driving cylinders 5 And 3 .

Fig.7. Hydraulic driven concrete pump:

A - general form; b – movement diagram of the auxiliary boom with concrete pipeline; V – circuit diagram concrete pump operation; 1 - ; 2 – incentive bunker; 3 And 5 – oil-driven cylinders; 4 – two supply cylinders;; 6 – horizontal slide gate; 7 – vertical slide gate.

The operating principle of such a concrete pump can be seen in Fig. V . The right working cylinder sucks the mixture from the receiving hopper, and the left working cylinder at this time squeezes it into the concrete pipe 1 (position І ). When the pistons reach their extreme positions, a signal is sent to the control system to change the direction of movement of the pistons and gate valves. In this case, the horizontal shutter opens the access of the mixture from the bunker to the left cylinder and closes its flow into the right cylinder. The vertical shutter opens the inlet of the mixture into the concrete pipeline from the right cylinder and closes the left cylinder (position ІІ ). Then the cycle is repeated, and the concrete mixture moves in a continuous flow through the concrete pipeline.

Concrete pumps with a hydraulic drive, compared to a mechanical one, have fewer structural components and are therefore more reliable in operation. Their working pistons move at a constant speed and do not create large inertial loads, unlike a crank mechanism. The performance of hydraulically driven concrete pumps can be adjusted within wide limits, and pressure increases above the set limit are prevented by hydraulic system safety devices. The delivery range of such gasoline pumps is greater than that of mechanically driven concrete pumps.

Hydraulically driven concrete pumps are equipped with a boom articulated from several links 8 , carrying a concrete pipeline. The boom is mounted on a rotating platform 9 , mounted on the frame of the concrete pump, and can rotate around a vertical axis. By changing the angle of inclination between the links with hydraulic cylinders, the boom head with the end link of the concrete pipeline moves to the desired position (Fig. b ). This, under certain conditions, makes it possible to supply concrete to the laying site without installing a concrete pipeline.

Structurally, depending on the purpose, concrete pumps are divided into three main categories :

1) – concrete pump;

2) - stationary trailed concrete pump;

3) - truck-mounted concrete pump with mixer.

1) - concrete pump– mobile construction equipment installed on the base of a truck. The equipment operates on the following principle: by means of a distribution boom, the concrete mixture is supplied from the concrete mixer to the place where it is directly laid. If necessary, the boom is extended with an additional concrete pipe. The type of truck chassis can range from two to five axles; the spreader boom reach depends on the design of the installation and ranges from 16,1 before 57 meters.

Fig.8. Truck concrete pump.

With increasing requirements for the pace and quality of construction and installation work, engineers developed mobile construction equipment. In the context of concrete pumping technology, truck-mounted concrete pumps were designed - concrete pumps mounted on a vehicle chassis.

The main difference between truck-mounted concrete pumps and stationary concrete pumps is their mobility.

Truck-mounted concrete pumps are designed to supply freshly prepared concrete mixture in horizontal and vertical directions with a distribution boom to the place of installation at construction sites. The use of concrete pumps significantly reduces the construction time of buildings and structures, improves the quality of construction, and improves working conditions.

The truck-mounted concrete pump, like its stationary counterpart, can operate in any weather conditions with a productivity of up to 150 m 3 /h ac, feed concrete to a height of up to 70 meters and up to 200 metro in horizontally.

Fig.9. External view of automobile concrete pumps.

Truck-mounted concrete pumps are equipped with a shock-absorbing system that minimizes vibrations caused by the operation of hydraulics. Modern automobile concrete pumps are equipped with an electronic system for monitoring the quality of the supplied concrete, and the distribution of the load on the boom is also regulated, which reduces the amplitude of vibrations of the structure.

A big advantage of the concrete pump, which made it possible to intensively use this type of equipment during the construction of the Shelter facility over the destroyed reactor Chernobyl nuclear power plant, is its mobility. This made it possible to start concreting the walls of the Sarcophagus remotely (at a distance) and organize the entire technological process of concreting in a short time.

Fig. 10. Diagram of operation of an automobile concrete pipeline

concrete pump (three-section boom)

The use of truck-mounted concrete pumps during the liquidation of the Chernobyl accident made it possible to significantly reduce the time required to complete the work, reduce labor requirements and reduce costs.

The need for remote concreting during the construction of the Sarcophagus

The construction of the Shelter facility, according to the original design, provided for complete isolation (disposal) of all premises belonging to the 4th block of the Chernobyl nuclear power plant. But after analyzing the radiation conditions at the work sites (inside the premises and on the territory of the Chernobyl Nuclear Power Plant), as well as examining the building’s building structures, it was possible to simplify the design of the Shelter facility.

When constructing the walls of the Shelter object, the following concreting procedure was provided. Reinforced concrete blocks were supplied to nuclear power plants in finished form. In the area with the most favorable radiation conditions, they were assembled into block formwork.

The assembled block was delivered to the location of the wall and after installing the concrete pipes and installing concrete pumps, the concrete mixture was placed into it.

Fig. 11. Layout of concrete pumps at

construction of the cascade wall of the Shelter object.

During the construction of some of the outer concrete walls of the Shelter, reinforced concrete blocks were mounted on railway platforms. The number of platforms was determined by the long wall. For the longest wall it took 14 platforms, the workplace for the assembly of reinforced blocks of which was determined in the area ABK-1, i.e. on distance 500-600 m from the site of wall construction. At the same time, the existing railway track was used to place the platforms and deliver the formwork to the location of the wall.

The greatest difficulty was the construction of a cascade wall with a height of 5,75 m in axes 43-51 along the row YU. Then the space between this wall and the block was concreted B to the top mark of the wall. On the formed step, getting as close as possible to the collapse, formwork was installed: reinforced concrete blocks with a height of 12 m, for the second wall behind which concrete was also laid, resulting in the formation of a second step - a tier of a cascade wall with a total height 17,55 metro V. Similar to the first and second tiers, the third one was erected (total height 29,75 m) and fourth (total height 41.00 m) tiers. The construction diagram of the cascade wall is shown in the figure. When constructing walls indoors, reinforced concrete blocks were installed in place separately. In some cases, the formwork was installed directly at the site where the walls were erected.

The supply of concrete to the reinforced concrete blocks was carried out using mobile and stationary concrete pumps, which made it possible to carry the concrete mix receivers at a distance 150-200 metro in from the installation sites of reinforced concrete blocks. The concrete pumps used include Worthington, Schwing, Putzmeister, BN-80-20.

According to the containment project developed by VNIPIET, during the construction of the “Shelter” it was necessary to lay more 300 000 m 3 concrete. At the same time, more than 7 thousand tons metal structures. The work began at the end of May 1986 and was completed in November 1986.

Construction of a concrete pump.

Fig. 12. Truck concrete pump:

1 – grappling hook; 2 – signal indicators; 3 – lubrication system; 4 –

fixing the final position of the telescopic device in front; 5 – left support control unit; 6 – water pump, drain valve; 7 8 – sound signal (horn) switch; 9 – mixer control panel; 10 – control unit panel; 11 – water pump control panel; 12 – control unit; 13 – concrete pump control unit; 14 – mast control unit; 15 – transport position locking device at the rear; 16 – right support control unit; 17 – fixing device for the final position of the telescopic device at the front.

Fig. 13. Truck-mounted concrete pump CIFA K48 XRZ

Truck concrete pump CIFA K48 XRZ mounted on a 4-axle chassis, equipped with a 5-section distributing boom B5RZ 48/44 with concrete pipe diameter 125 mm With RZ-shaped opening kinematics, X-shaped retractable outriggers, which speeds up the installation of the concrete pump and simplifies its placement in narrow areas. The boom is equipped with a system B.F.C.(quick-release fastening of the concrete pipeline), and proportional control of the boom opening allows the operator to independently control the opening of the sections.

Main characteristics:

Compact and convenient design, designed for installation on a four-axle chassis.

Rear folding and front folding with telescopic support.

Independent frame with protection against torsional deformation.

Hydraulically driven outriggers on both sides of the machine.

Five-section dispensing boom B5RZ 47/43 diameter 125 mm with mixed Z-shaped and unwinding kinematics of opening.

Proportional boom control allows the operator to independently control the boom sections.

Concrete supply regulator.

Possibility of installing a series pump unit HPG-IF with closed hydraulic circuit: superior performance, high pressure and flow of concrete, easy to maintain.

Safety device on the opening inspection hatch.

Pump series " F8"high performance: smooth, continuous flow of concrete combined with ease of maintenance.