Where did the dredger come from? Types of dredgers and principles of excavation and removal of soil How a dredger works on water

Hydraulic works related to the extraction of soil or the extraction of minerals require the use of special equipment. Among such equipment is a dredging projectile. The effective operation of a dredger on a river or other body of water directly depends on the knowledge of the principles of its operation and operational characteristics.

What is a dredge

A dredger is a watercraft, the purpose of which is to pump eroded soil (pulp) by means of a powerful pump through a pipeline to a predetermined distance - into a hold or ashore. The vessel is equipped with the necessary equipment for work and can be used for:

cleaning of reservoirs from bottom sediments, as well as for their deepening;
alluvium of dams, dams and beaches, roads and areas during construction;
extraction of sand, gravel, sapropel, precious metals;
cleaning of settling tanks of industrial, agricultural enterprises;
development of ash and slag accumulators for enterprises of the coal, coke-chemical, metallurgical, mining and processing industries;
laying trenches for pipelines and trenches with their subsequent flushing.

Why else do you need a dredger? Special equipment may be needed during the liquidation of the consequences of floods, the construction of sea and river ports, the strengthening of the coast, protective dams and other significant hydrotechnical facilities.

Dredge device

Considering the design of hydraulic equipment, several groups of devices can be distinguished according to their functional affiliation.

What is a dredger made of?

main components: soil intake device, suction pipeline, soil pump, pressure pipeline, aggregates for moving the soil intake device;
auxiliary equipment: dredger body, lifting and lowering mechanisms, auxiliary pumps for supplying clean water, power plants;
safety and productivity equipment: control system, instrumentation, heating, ventilation, fire fighting devices, warning, lighting and communication systems.

The drawing of the dredger clearly shows the scheme of its design:

How does a dredger work

The continuous operation of the dredger depends on the characteristics of the pumping device (dredge pump), which must have high abrasive resistance in the flow path. The priming pump is often placed in the hold - this technique avoids the cavitation process, which reduces the life of the equipment.

The principle of operation of the dredger for cleaning water bodies is as follows:

after preliminary calculations of the feed rate of the mixture and the patency of the pipeline, the soil pump with water poured inside is lowered to the bottom of the reservoir, the engine and gearbox are started;
after that, air is pumped out of the suction pipe;
the resulting vacuum draws in water with soil particles;
the slurry enters the pump and is pumped ashore (cargo barge);
the movement of the entire system is carried out with the help of pile driving or winches (a combination is possible).

General control is carried out from the bagermeister cabin, where there is a control panel with access to all the functions of the dredger: from starting the main equipment to turning on a small light bulb.

Characteristics and operation of dredgers

The choice of the right equipment is directly dependent on its performance. The technical characteristics of the dredgers determine the range of possible tasks for implementation. These indicators include:

productivity - this indicator can be from 1 m³ / h (for mini-equipment used in personal subsidiary plots) up to 5000 m³ / h on solid ground, it all depends on the task;
power supply method - diesel, electric or mixed;
type of soil intake device - milling, rotary, free suction (depending on the type of soil);
type of slurry pipeline - metal for work at one point of discharge of ash pulp or rubber-woven (plastic) with frequent movements;
the size of structural units - this indicator is important if it is necessary to frequently transfer equipment.

It is worth considering the expected depth of development, the flow rate, the environment of use (salty, alkaline, fresh).

Types of dredgers

The classification of dredgers is carried out according to several criteria:

by hourly productivity: extra small (up to 50 m³/h), small (50-200 m³/h), medium (200-500 m³/h), large (500-1000 m³/h), extra large (over 1000 m³ /h);
by design: collapsible and non-collapsible;
according to the method of soil intake: with or without preliminary loosening;
according to the method of movement: non-self-propelled and self-propelled;
according to the method of control: with manual, remote, automatic control.

All types of dredgers are divided according to the method of transporting the soil, the type of power supply, the location of the main equipment, the number of soil pumps, and the presence of living quarters on board.

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Technology of work of dredges

Dredger - the general name of the vessels of the technical fleet used for underwater mining and excavation during dredging, in hydraulic engineering.

According to the method of collecting and moving soil, dredges are divided into:

1. Suction dredger - extracting and pumping soil in the form of pulp using a soil pump, the most common type of dredge used on I-IV soil classes;

2. Dredgers - which are a type of excavators that lift and move the soil by means of buckets or scoops. They are used on hard soils of class V-VI, where the efficiency of suction dredgers does not provide the required productivity. In turn, dredging shells are divided into:

1. Single-bucket rod excavators, which are a single-bucket excavator mounted on a pontoon;

2. Single-bucket grab, which is a crane equipped with a grab;

3. Multi-bucket, which is a machine of continuous action, with scoops fixed on an endless chain stretched between two drums.

According to the method of transporting soil, dredgers are divided into:

1. Refuller - soil transportation is carried out using a floating slurry pipeline. The most cost-effective method of pulp transportation. If transportation over long distances is required, additional Booster stations are used.

2. Scow - transportation of soil is carried out by scows - special vessels that take the soil into the hold and take it to the place of placement.

3. Self-carrying - the soil is taken by the dredger into its own hold and transported to the dump site.

4. With jet slurry ejection. This method is used when working on the estuarine sections of rivers and on reservoirs with frequent waves; it has received the widest application for hydraulic reclamation in sea water conditions.

According to the method of working movements

1. Self-propelled

2. Non-self-propelled - using papillon winches and anchors or pile driving. The anchor is brought in for a certain distance and with the help of ropes and winches the projectile moves in the right direction. Pile-anchor shells, in addition to working anchors, also have pile machines.

According to performance, there are:

Shells of small, medium and high productivity.

According to the type of power plant (setting the projectile in motion) - steam, diesel, diesel-electric, diesel-hydraulic, gas turbine and electric dredging projectiles.

In the area of dredging - shells of sea and river types. Marine dredgers differ from river dredgers in the design of the hull and better stability, which allows them to work in rough conditions.

Development of trenches with suction dredgers

Suction dredgers are advisable to use on non-cohesive soils of small size (sands and fine gravel): The principle of operation of dredgers to extract soil from the bottom of the water area is to suck from the bottom of the water area a mixture of soil particles with water, called pulp. The scheme of the suction dredger is shown in fig. 1. The main working body of the dredger is a centrifugal pump that creates a vacuum and sucks the pulp through the soil intake device (sucker) 1. The sucker can change its position (lower or rise) with the help of a lifting device. Through the sucker, the pulp enters the soil pump 3, which delivers it to the pressure pipeline 4. The suction depth of modern suction dredgers varies from 2–3 to 40–50 m, and the productivity is 80–3000 m3 / h. Vessels are covered with a grate to prevent the entry of large stones or long objects that could damage the centrifugal pump impeller. Modern suction dredgers have special hydraulic, mechanical and combined devices for loosening the soil. For the development of dense non-cohesive and cohesive soils, the designs of suction devices are equipped with mechanical soil disintegrators - milling and rotary bucket.

Rice. 1. Schematic diagram of the suction dredger: 1 - soil intake device; 2 -- suction pipeline; 3 - soil pump; 4 - pressure pipeline; 5 -- device for working movements; 6 -- body

For easily eroded soils, it is advisable to use hydraulic openers, which ensure the supply of pulp with a higher soil content to the sucker. Hydraulic looseners are divided into three types: eroding the soil, eroding and adjusting the soil to the suction and hydrodiffusion. The most effective disintegrators of hydrodiffusion action, they provide the consistency of the pulp up to 30--40%. dredger trench rod grapple

Combined rippers include milling and hydraulic. These rippers significantly increase the performance of dredgers and expand their range of applications. The milling-hydraulic ripper consists of a cutter and a system of hydraulic nozzles, one of which (frontal nozzle) is designed to loosen the soil in the front part of the face, and the remaining nozzles are located on the cutter blades and are designed to flush the soil from the cutter blades, loosen it and fit it to the suction .

With an increase in the depth of development of underwater soil, the productivity of suction dredgers is significantly reduced. An increase in the productivity of suction dredgers is achieved by using ejectors on the suction line of the dredger.

For the development of underwater trenches, airlift dredgers can be used. The principle of operation of the airlift is based on the fact that compressed air, entering through the nozzle into the lower end of the pipe lowered into the water, mixes with water and forms a water-air mixture, the density of which is lower than the density of the surrounding water. Due to the difference in density and water pressure, the water-air mixture rises. If the lower end of the pipe is connected to the soil receiver and brought closer to the ground, then, together with water, it begins to flow into the pipe and the soil. With an airlift dredger, with an increase in the diameter of the soil pipeline and the depth of soil extraction, productivity increases. The main advantage of the airlift is the ability to extract soil from great depths.

Development of trenches with bucket shells

Bucket shells are based on the mechanical method of separating and lifting the soil. By design, they are divided into single-bucket, developing soil with one bucket, and multi-bucket, developing soil with buckets mounted on an endless bucket chain.

It is advisable to use multi-bucket shells mainly on heavy soils of categories V-VII or on clogged soils.

For the development of underwater trenches in heavy soils, single-bucket clamshell and rod shells are used.

A clamshell is a dredging projectile that extracts soil from the bottom of a reservoir with a clamshell crane. The clamshell projectile is moved during excavation with the help of working anchors, ropes and winches. A clamshell crane separates the soil from the bottom of the reservoir, lifts it out of the water and loads it into its ground hold or into a scow. Clamshells can be used for the development of soils: light, medium, heavy, with inclusions of boulders, stones, driftwood. For this, grab cranes are equipped with grabs (ladles) of various types. Light and medium soils are developed with double-jaw grabs, undermined rocky soil - with multi-jaw grapples, boulders and other single objects - with grate grabs. The most widespread are grabs with a volume of 1-2.5 m3, there are grabs with a volume of up to 13 m3. The depth of excavation varies widely. Most grab cranes have a digging depth of up to 15-21 m.

Rod projectiles are used in cases where large cutting forces are required to extract the soil. The rod projectile for soil extraction has a single-bucket excavator equipped with a straight shovel. The excavator cuts the soil with a bucket, lifts it from the bottom and unloads it into a scow or dump. During the intake of soil, the horizontal component of the soil reaction is transmitted through the excavator to the ship's hull and tends to shift it in the direction opposite to the bucket movement. This force reaches a large value, therefore, so that the projectile does not move, it is fixed with the help of three or four piles. With three piles, two - piercing ones are installed in the bow of the projectile (near the excavator), and one - stubborn - in the stern. With four piles, two are installed in the bow and stern parts. The bow piles are immersed in the ground vertically, and the stern piles with a certain slope for better perception of the horizontal force. After the development of the soil at the parking lot, the projectile moves to a new area. To do this, the bucket is brought forward and lowered to the bottom, then the piles are raised with winches and the projectile body is pulled up or deployed. Rod shells differ in performance, digging depth, bucket volume, boom reach and bucket height above the water. The productivity of rod projectiles is mainly 100-200 m3/h, and for powerful projectiles it can reach 600 m3/h. The maximum digging depth usually does not exceed 20 m. The volume of the bucket of rod shells varies between 0.3-15 m3. Rod shells have interchangeable buckets for the development of heavy and relatively light soils.

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How does a dredger work

The principle of operation and the device of the dredger are a complex system, where the main working body is soil sucker- a pumping device with a high resistance to abrasive in the flow part.

As a rule, soil pumps are placed in the hold of the vessel. This is necessary so that the axis of the pump itself can be lowered below the water level marks. This technique prevents the occurrence of the cavitation process, which significantly reduces the time of normal operation of the pump.

With the help of a soil pump, soil particles connected with water are sucked up from the bottom. Further, the installation pumps particles through pipes to the shore or to a scow, also called a dirt barge.

In addition, the dredgers are equipped pumps for technical water supply. The main pumps are hydroloosening and ejection.

Hydraulic loosening is necessary when developing in non-cohesive soils. This type of soil includes sand-gravel mixtures and sand. A water jet, supplied under high pressure, crashes into the bottom of the reservoir. In this case, suspended particles from the pulp and water appear. By means of an ejection pump, water is supplied to the suction pipe inside the soil pump. This process reduces the effort required to suck the mixture from a great depth. Thanks to the operation of pumps for industrial water supply, the efficiency of the main pump is increased. This is important for the execution of works, the terms of which are limited.

Equipment movement

In order for the suction dredger to work properly, it needs to move on the water surface. Movement on water is possible with the help of winch or special pile driving. There are ships in which the device and principle of operation of the dredger combine the two above options.

Ground movement

An equally important element of dredgers can be called pipeline, which serves to transport the pulp. Some time before the start of work, parameters are calculated that include the total length of the pipeline, the diameter of all pipes, the subtleties in the installation of the pipeline and its use. During operation, hydrostatic pressure is created in the pipes. It may be too large for the main pump. Therefore, it is necessary to perform a hydraulic engineering calculation for all working elements of the dredger.

Control

In the ship, from the cabin of the bagermeister, the process of the dredger's work is directly controlled. The control panel includes many instruments and sensors. All existing systems are controlled from the bagger remote control: from starting the dredger to turning on a light bulb in the engine compartment.

Over time, water bodies, large and small, become polluted: garbage, bottom sediments accumulate in them, and algae flourish. As a result, ponds, lakes and rivers become shallow and turn into swamps. To prevent this from happening, ponds must be constantly looked after.

On large rivers and lakes, this work is carried out with the help of dredgers, which are vessels of the technical fleet.

With their help, they not only clean and maintain the depth of the reservoir at the right level, but also extract non-metallic building materials.

For small rivers, ponds, pools, units of much lower power are used - mini-dredgers. Equipment of this type was first developed and put into production in the United States.

At present, mini-dredgers have found their consumer in the CIS countries. Moreover, in Russia they began to produce their own mini-dredgers.

The main nodes of mini-dredgers ^

Mini dredges consist of the following units:

float tool;
soil intake mechanism equipped with a milling ripper.

The blades of the ripper are wedge-shaped. There are holes in their back walls. Through them, the drive shaft communicates with the bottom.

The soil intake mechanism is mounted on a float (catamaran) using a frame, which includes:

slurry pipeline;
drive shaft;
barbell;
hinge device.

The craft is equipped with handles for carrying it.

If you need a mini-dredger for some one-time work, it is not necessary to buy it, there are many companies that rent dredgers. What pitfalls can be here, what you need to know when drawing up a lease, read the article, it contains a lot of useful information.

The minidredger can be made "to order", according to your specific needs. What you need to pay attention to when producing a dredger, what documents are needed and much more, only on our website!

Scheme of work ^

The cutting edges of the ripper blades loosen the sediment. Through the holes in the edges of the blades, atmospheric air is sucked in, which is mixed with the disturbed sediment.

Air serves as a kind of "lubrication" for the next blade. The gruntosos sucks in the sludge stirred up in this way and transfers it to the slurry pipeline.

Where is the mini dredger used ^

Due to the small size and weight of mini-dredgers, they become indispensable when performing work on objects that are hard to reach for large special equipment:

restoration of old and resurfacing of new beaches;
cleaning and deepening of small reservoirs - rivers, ponds, canals;
preparation of a reservoir for swimming;
sapropel mining;
reed washing, etc.

Removing vegetation for a mini-dredger is an impossible task(as well as for most large machines), but you can blur the root system with their help. Large debris, stones, etc. are removed manually.

Not all mini dredgers are the same ^

There are many mini-dredgers: for domestic and industrial use, for performing various kinds of work or universal.

The three main brands of mini-dredges are in the greatest demand:

Crab;
Gudgeon;
Piranha.

Each brand is represented by different models that are designed for a specific type of work.

Crab ^

Produced in Vologda. The unit, due to its compact size, can be easily transported to the place of work by a Gazelle or a car trailer.

The manufacturer produces three modifications of the "Crab":

Crab - Auger: designed to clean water from vegetation. Has a screw ripper. Price - 175 thousand rubles;
Crab - Standard: equipped with pumps and designed not only for cleaning, but also for deepening the reservoir. In addition, this model can be used in the extraction of sapropel and sand. Such a unit costs 180 thousand rubles;
Crab - Combined: in this modification, the auger ripper is combined with pumps. The cost is 215 thousand rubles.

As for the method of movement, all three modifications work on the principle of a foot-operated catamaran. But on any of them, if desired, you can install a boat motor.

Minnow ^

Another unit of domestic production. It belongs more to the industrial group of equipment. They produce a mini-dredger "Peskar" in Yaroslavl.

This machine can be used not only for cleaning small reservoirs: it successfully copes with the task of environmental cleaning of sedimentation tanks of chemical, metallurgical plants, water intakes of hydro and nuclear power plants, and treatment facilities.

Gudgeon is also used for alluvium dams, dams, construction sites.

This model weighs 1.5 tons, although the dimensions are very modest: 915x875x875 mm.

The hull of the Minnow can be made both in the form of an all-welded and collapsible pontoon structure.

Inside the pontoon is divided into compartments. They are waterproof, which protects the unit from flooding if any of them are damaged.

Mechanisms and devices of the unit are mounted on the deck of the pontoon.

Papillon winches (electric or manual) are installed in the middle part of the machine (on the right and left sides). In addition to them, in the same area there is a stern winch.

The design has two pumps:

ground;
hydraulic opening.

As a soil pump, a pump is used, designed to work in difficult conditions. The soil intake device can perform work at a depth of up to 6 meters.

Dredger "Gudgeon" can also be used in case of emergencies:

for pumping water during flooding;
when extinguishing fires;
when burning peat masses, etc.

With the help of this model, it is possible to clean a mine well from silt deposits.

The cost of "Peskarya" is about 750 thousand rubles.

Piranha ^

Piranha is a guest from America. The dredge with such an aggressive name was developed at the request of many Americans who were lucky enough to live in the coastal zone.

But silt, black mud greatly spoil the appearance of the beaches. Therefore, the owners have to spend a lot of effort to maintain them in good condition.

Piranha came to their aid. The basis of the unit is a catamaran. The speed of excavation (depending on the model) is from 15 to 30 cubic meters per hour. The units are equipped with a Honda gasoline engine.

The machine is not designed to perform large amounts of work: it, of course, will cope with it, but it will take you a lot of time. But you can clear a small area around the dock or boat dock in an hour and a half.

Mini-dredgers "Piranha" belong to the non-industrial group of equipment. They can be used to do the following:

remove bottom sediments from fish ponds, docks, small lagoons, canals;
clean artificial, fire reservoirs (pools);
strengthen the shore, deepen the bottom, widen the canal or river, wash the beach, etc.

The cost of a mini-dredger Piranha PS-135-E (economy version) performance 30 cu. m/hour – 599 thousand rubles.

The dredger is a machine used for the construction of harbors and canals, land reclamation, in mining projects, as well as in transport construction (including road construction).

Depending on the purpose, different models of dredgers may differ in some way from each other, but in general, the following list of components and assemblies can be distinguished, typical for this type of machine:

Frame.

It is made in the form of pontoons. It serves as the basis for placing all the necessary working mechanisms.

Papillon piles and pile apparatus.

Located at the back of the case. Provide movement of the dredger in the course of excavation.

Deck superstructure.

Located on the central pontoon. Includes control cabin with all the necessary set of control and measuring equipment.

Hydrotransport plant.

Placed in the hold of the car. Consists of the following elements:

soil pump;
power plant (drive);
suction slurry pipeline;
pressure slurry pipeline.

As a power plant can be used:

electric motor;
diesel-electric installation;
diesel engine.

The suction slurry pipeline is a pipe connecting the soil pump and the soil intake device.

The soil pumped out by the pump is fed into the pressure slurry pipeline, through which it is transported to the floating slurry pipeline, and then to the onshore one.

Ripper.

The working body of the dredger, with the help of which the soil is being developed.

Arrow.

Using the boom, the operator adjusts the depth of development, and also moves the ripper. The lifting and lowering of the boom is carried out with the help of a winch, for which a steel cable is fixed on its head.

Equipment for water supply.

Performs an auxiliary function of flushing, cooling and compacting the soil pump parts.

Before you start placing an order for a dredger, it would not be superfluous to find out what it is like today, what it consists of, and so on, read about it in our article.

In the event that buying a dredger is too expensive, a good option is to rent it. How this is done and what is needed for this - read, the latest and most relevant information.

Dredge production ^

The production of a dredger is a complex of works in which the direct manufacture of the machine is only the final stage.

First of all, the customer fills out a questionnaire and draws up a technical assignment, in which he describes in as much detail as possible the requirements for the future machine, as well as all the features of the planned dredging or alluvial works.

The design department of the manufacturer examines the terms of reference and the questionnaire, and also analyzes information about the type of soil being developed, currents and waves in the operating area of the designed dredger, climatic conditions, navigation, distance to unloading the soil.

In addition, the possibility of transport delivery of dredger modules to the place of work is taken into account.

The information obtained serves as the basis for the development of a dredger project, in which, first of all, the type of the future machine is determined and justified. Depending on the task and working conditions, this can be:

dredger with rotary cultivator: provides high-quality loosening of the soil, but cannot be used on hard rocks.
dredger with milling ripper: able to work with almost any type of soil. Provides a fairly even bottom profile. Flaw: May interfere with navigation.
dredger with free suction: instead of a baking powder, hydraulic erosion of the soil is used, which is then sucked up by the soil pump into the slurry pipeline. The best option for the development of loose soils.
dredger on caterpillar tracks: Suitable for all types of ground, except for hard rocks or soils containing large stones. If the waves and current are below the pontoons, they have little effect on the operation of this machine. It has extremely high mobility and stability.
multi-bucket Dredger: The use of this type of dredger is driven by the need to keep the excavated rock relatively dry. Requires a barge or floating conveyor belt to unload soil. Nowadays, it is most often used for the extraction of minerals: gold, diamonds, tin, etc.
grapple or multi-grab dredger: The performance of these dredgers depends on the cycle time and bucket volume. Advantages: allows you to develop at great depths and extract large stones, easy to operate, has a relatively low cost.
Backhoe dredger: Great for hard soil excavation. At the same time, it allows you to quite accurately plan the profile of the bottom.

When developing a project, engineers determine the required dimensions of the working bodies and other components of the dredger, select the type and power of the drive, calculate the required load capacity of the winch, etc.

At the place of production of the dredger, only a partial assembly of the individual components of the machine takes place in such a way that it is transportable.

This point is very important, as more and more projects are being carried out in remote areas with undeveloped shipping. The dredger can only be delivered to such regions by car or rail. That is why it is so important at the design stage of the machine to provide for the possibility of its delivery by these modes of transport.

An example of such mobility is the BEAVER dredgers from IHC, individual blocks of which are adapted to international container standards.

The final assembly of the dredger and launching are carried out at the work site.

How to determine the quality of a dredger ^

Before signing a contract for the supply of a dredger, experts recommend visiting the manufacturing facilities of the manufacturer.

This visit will give you the opportunity to personally verify the quality of the assembly work, to check how well and with what equipment the welds are performed.

A sign of a solid, reliable and durable design is the presence on the body of the machine of the so-called ship set. It is a strong skeleton of rolled metal beams of angle, tee or strip profile.

Ensure that the foundations under machinery and equipment are secure.

If they are not strong enough, under the influence of engine vibration, the entire structure will quickly become loose and you will have to spend a lot of time and effort welding and patching numerous cracks.

It is desirable that the design of the dredger provides for disassembly into a minimum number of modules that can be conveniently transported.

Do not forget that for proper operation, as well as the possibility of repair, the dredger must be accompanied by comprehensive operational documentation:

passport (form);
specification;
technical description;
user manual.

If you do not need a "large" dredger, then you may be interested in a mini-dredger. About these units, different companies and names, for example, Minnow, Crab and others, make the right choice.

What is a dredge

Dredge device

How does a dredger work

Characteristics and operation of dredgers

Types of dredgers

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Similar Documents

How does a dredger work

Equipment movement

Ground movement

Control

The main nodes of mini-dredgers ^

Scheme of work ^

Where is the mini dredger used ^

Not all mini dredgers are the same ^

Crab ^

Minnow ^

Piranha ^

Dredge production ^

How to determine the quality of a dredger ^