The principle of operation of the dredger. Dredger: principle of operation. Technical performance of the dredger qtech

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Dredger operating technology

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

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

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

2. Dredgers - which are a type of excavator that lifts and moves soil using buckets or scoops. They are used on hard soils of V--VI class, where the efficiency of suction dredgers does not provide the required productivity. In turn, dredging equipment is divided into:

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

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

3. Multi-bucket, which is a continuous machine, with scoops attached to an endless chain stretched between two drums.

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

1. Refuler - soil is transported using a floating slurry pipeline. The most cost effective method of transporting pulp. If transportation over long distances is necessary, additional booster stations are used.

2. Scow - transportation of soil is carried out by scows - special vessels that receive soil into the hold and transport it to the location.

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

4. With hydromonitor pulp ejection. This method is used when working at the mouths of rivers and reservoirs with frequent waves; it is most widely used in hydrowashing in sea water conditions.

According to the method of working movements

1. Self-propelled

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

According to performance they are distinguished:

Projectiles of low, medium and high productivity.

By type of power plant (which drives the projectile) - steam, diesel, diesel-electric, diesel-hydraulic, gas turbine and electric dredging equipment.

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

Development of trenches with suction dredgers

It is advisable to use suction dredgers on non-cohesive soils of small size (sand and fine gravel): The principle of operation of dredgers for extracting soil from the bottom of a water area is to suck a mixture of soil particles and water, called pulp, from the bottom of the water area. The diagram of the suction dredger is shown in Fig. 1. The main working part of the dredger is a centrifugal pump, which creates a vacuum and sucks in the pulp through a soil intake device (sucker). 1. The sucker can change its position (lower or rise) using a lifting device. Through the suction pump, the pulp enters the soil pump 3, which delivers it to the pressure soil pipeline 4. The suction depth of modern dredging units varies from 2-3 to 40-50 m, and the productivity is 80-3000 m3/h. The vessels are closed with a grid to prevent the entry of large stones or long objects that could damage the impeller of the centrifugal pump. Modern suction dredgers have special hydraulic, mechanical and combined devices for loosening the soil. To develop dense non-cohesive and cohesive soils, the designs of suction devices are equipped with mechanical soil looseners - milling and rotary-bucket.

Rice. 1. Schematic diagram of a 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 loosening agents, which supply pulp with a higher soil content to the sucker. Hydraulic loosening agents are divided into three types: eroding the soil, eroding and pushing the soil to the suction, and hydrodiffusion. Hydrodiffusion disintegrants are the most effective; they provide pulp consistency of up to 30-40%. trench dredger rod grab

Combined rippers include milling-hydraulic ones. These rippers significantly increase the productivity of dredgers and expand their range of applications. The milling-hydraulic ripper consists of a milling cutter and a system of hydraulic attachments, one of which (the frontal attachment) is designed to loosen the soil in the front part of the face, and the remaining attachments are located on the cutter blades and are designed to wash off the soil from the cutter blades, loosen it and fit it to the sucker .

With increasing depth of underwater soil development, the productivity of suction dredgers is significantly reduced. Increasing the productivity of suction dredgers is achieved by using ejection devices on the suction line of the dredger.

Airlift dredgers can be used to develop underwater trenches. The operating principle of the airlift is based on the fact that compressed air, entering through a nozzle into the lower end of a pipe lowered into 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 upward. If the lower end of the pipe is connected to the soil receiver and brought closer to the ground, then it begins to flow into the pipe and the ground along with water. With an airlift dredger, increasing the diameter of the soil pipeline and the depth of soil extraction increases the productivity. The main advantage of the airlift is the ability to extract soil from great depths.

Development of trenches using bucket shells

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

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

To develop underwater trenches in heavy soils, single-bucket grab and rod projectiles are used.

A grab dredger is a dredging device that removes soil from the bottom of a reservoir using a grab crane. When excavating soil, the grab tool is moved using working anchors, ropes and winches. A grab crane separates the soil from the bottom of the reservoir, lifts it out of the water and loads it into its soil hold or into a scow. Grab excavators can be used to develop soils: light, medium, heavy, with inclusions of boulders, stones, and driftwood. For this purpose, grab cranes are equipped with grabs (buckets) of various types. Light and medium soils are developed with double-jaw grabs, undermined rocky soil with multi-jaw grabs, boulders and other single objects with lattice grabs. The most common are grabs with a volume of 1-2.5 m3; there are grabs with a volume of up to 13 m3. The depth of soil development 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 soil. The rod tool for extracting soil has a single-bucket excavator equipped with a straight shovel. An excavator cuts the soil with a bucket, lifts it from the bottom and unloads it into a scow or dump. During soil extraction, 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 movement of the bucket. This force reaches a large value, therefore, so that the projectile does not move, it is secured with the help of three or four piles. With three piles, two - anchor piles - are installed in the bow of the projectile (at the excavator), and one - thrust - in the stern. With four piles, two are installed in the bow and stern parts. Bow piles are immersed vertically into the ground, and stern piles are immersed with a slight inclination for better perception of horizontal force. After excavating the soil at the parking site, the projectile is moved to a new site. To do this, the bucket is brought forward and lowered to the bottom, then the piles are lifted with winches and the projectile body is pulled up or deployed. Rod projectiles vary in productivity, digging depth, bucket volume, boom reach and height of bucket lift above the water. The productivity of rod projectiles is generally 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 rod projectile bucket varies within 0.3-15 m3. Rod projectiles have replaceable buckets for developing heavy and relatively light soils.

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Production of dredgers^

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

First of all, the customer fills out a questionnaire and draws up a technical specification, in which he describes in as much detail as possible the requirements regarding the future machine, as well as all the features of the planned dredging or reclamation work.

The design department of the manufacturer studies the technical specifications and the questionnaire, and also analyzes information about the type of soil being developed, the current and waves in the operating area of the designed dredger, climatic conditions, navigability, and the distance to unloading the soil.

In addition, the possibilities of transport delivery of dredger modules to the work site are taken into account.

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

dredger with rotary ripper: provides high-quality loosening of the soil, but cannot be used on hard rocks.
dredger with milling ripper: capable of working with almost any type of soil. Provides a fairly even bottom profile. Flaw: May interfere with shipping.
dredger with free suction: instead of a loosening agent, hydraulic erosion of the soil is used, which is then sucked into the slurry pipeline by a soil pump. The best option for developing loose soils.
dredger on caterpillar tracks: Suitable for all types of soil, except hard rocks or soils containing large stones. If waves and currents are below the pontoons, they have virtually no effect on the operation of this machine. Has extremely high mobility and stability.
multi-bucket Dredger: The use of this type of dredge is driven by the need to keep the rock being extracted relatively dry. Requires a barge or floating conveyor belt for loading soil. Nowadays, it is most often used for the extraction of minerals: gold, diamonds, tin, etc.
grab or multi-grab Dredger: The performance of these dredgers depends on the cycle time and bucket volume. Advantages: allows you to mine at great depths and extract large stones, is easy to operate, and has a relatively low cost.
Backhoe Rod Dredger: Great for hard soil excavation. At the same time, it allows you to quite accurately plan the bottom profile.

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

At the production site of the dredger, only partial assembly of the individual components of the machine takes place so that it is transportable.

This point is very important, since an increasing number of projects are being carried out in remote areas with poor navigation. The only way to deliver a dredger to such regions is by car or rail. That is why it is so important at the design stage of the machine to provide for the possibility of delivering it 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 production facilities of the manufacturer.

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

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

Make sure the foundations under the 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 dredger design allows 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 don’t need a “big” dredger, then you might be interested in a mini dredger. About these units, of different companies and names, for example, Minnow, Crab and others, make the right choice.

Dredging equipment, regardless of type and purpose, has the following main parts:

1) the housing, which houses all the working, power and auxiliary equipment of the projectile;

2) dredging device (working body);

3) the main power plant driving the dredging device;

4) deck mechanisms for operational movements of the hull during soil collection;

5) means of controlling the operation of the dredger.

7.4.1. Dredgers

Dredgers, as already noted, use a hydraulic method for separating soil from the bottom and transporting it through pipelines to the dump site. The design diagram of a river dredger is shown in Fig. 7.10, 7.11.

The body of the river dredger is of simple rough contours, has a cutout (slot) to accommodate a suction pipe with a frame enclosing it. The main working part of the dredger is a centrifugal type soil pump, which ensures the suction of the water-soil mixture and its movement along the soil pipelines. The pump is driven by the main motor of the dredger. When the main engine is stopped, the dredger is supplied with energy from an auxiliary diesel generator.

The inlet part of the pump is connected to the suction pipeline, and the outlet part is connected to the pressure pipeline. The main part of the suction pipeline is an inclined suction pipe that rotates in a vertical plane. It communicates through a flexible connection with the body suction pipeline connected to the soil pump. At the end of the suction pipe there is a suction tip (soil receiver). Raising and lowering the inclined suction pipe to the required depth is carried out using a frame lifting device.

The pressure pipeline consists of a hull and a floating part. A vertically located pipe is connected to the pump, behind which there is an elbow with a large radius of curvature that directs the water-soil mixture (hydraulic mixture) into a horizontally located section of the body soil pipeline. This section is located on the roof of the dredger's upper superstructure. In the aft part of the projectile, the hydraulic mixture goes down through two elbows and an inclined soil pipeline, to the point where the floating soil pipeline is connected. The floating pipeline is connected to the pressure hull pipeline using two ball joints. Such a connection provides the necessary degree of mobility, both in the horizontal plane and in the vertical, when the dredger, as fuel is consumed, begins to “float” in relation to the floating part of the pressure pipeline.

The floating pipeline (refuler) is located on pontoons and its individual links (pipes) are connected to each other using flexible connections. A pontoon consists of two floats rigidly connected together. The last pontoon of the refuler, called the end pontoon, is equipped with two anchors, cables and winches. Anchors and cables serve to hold the pontoon in place of the soil dump, to lower the pontoon downstream, and also to move the pontoon to the sides from the axis of the dump.

The principle of operation of the dredger for extracting and draining soil is as follows. The soil pump is filled with water and driven by the main engine. Using a frame-lifting device, the suction pipe is buried in the ground. When a pump filled with water operates, a vacuum (pressure below atmospheric) is created in the suction pipe. Above the soil receiver there is atmospheric pressure and the pressure of the water column, corresponding to the depth of lowering the soil receiver. Under the influence of the pressure difference, the water located in front of the soil receiver begins to enter it at a certain speed. Water flowing into the receiver captures and carries away soil particles. The space around the throat (hole) of the soil receiver, within which water erodes and carries away the soil, is called the suction sphere. A mixture of soil particles and water (hydraulic mixture) moves through the suction pipeline to the pump. In the pump, the hydraulic mixture falls on the rotating blades of the impeller and is thrown into the beginning of the body part of the pressure pipeline, where increased (above atmospheric) pressure is created. Near the outlet of the floating refuler, the pressure is equal to atmospheric pressure. Under the influence of pressure differences, the hydraulic mixture moves along the pressure pipeline to the soil dump site.

The productivity of the dredger on the ground, m 3 / h, is determined by the expression

Where: Q cm – hydraulic mixture consumption (dredder pump productivity per mixture), m 3 /h;

R– consistency of porous soil (soil content in the hydraulic mixture), %;

V cm– speed of movement of the hydraulic mixture in the pressure pipeline, m/s;

D n– diameter of the pressure pipeline, m.

The soil content in the hydraulic mixture is usually characterized consistency(saturation). When dredging under consistency R understand the ratio of the volume of soil together with pores (with porosity characteristic of the soil at the bottom before its development) to the volume of the hydraulic mixture. A saturation of 15–18% is considered satisfactory when developing light soils and 12% when developing heavy soils.

The soil productivity of river dredgers operating on inland waterways ranges from 200 to 2500 m 3 /h.

Dredgers are usually used in the development of non-cohesive, mainly sandy and sandy-gravel soils. To work on cohesive (clayey) soils, dredgers are equipped with mechanical loosening agents, with the help of which the soil is cut and brought to the suction hole of the soil receiver.

Currently, on inland waterways, dredging outside the shipping channel is increasingly being used. refuler milling dredgers(Fig. 7.12, 7.13). They are not used to deepen exploited transit ship passages due to the need to allow ships to pass through.

The basic principle of operation of such a projectile is as follows. The dredger, equipped with a cutter at the end of the frame and soil pumps, excavates the soil using a pile-cable system of working movements. The cutter separates the soil from the bottom and forcibly transfers the loosened soil to the active suction zone, from where it is carried away by the flow of water into the receiving hole of the suction soil receiver located in the cavity of the cutter. The hydraulic mixture is transported via a floating pipeline using soil pumps to the site where the soil dump is laid.

A distinctive feature of the soil intake device of a pile-anchor dredger is the presence of a durable metal frame, on the upper belt of which a shaft line for a mechanical loosening agent is installed.

The lower end of the shafting carries a mechanical breaker on its cantilever part. The upper end of the shaft line is connected through a gearbox to the ripper motor. The inclined suction pipe is placed inside the frame. The suction of the hydraulic mixture is carried out by a soil receiver, the mouth of which is located inside the loosening cutter.

To increase the efficiency of soil intake and increase the suction depth, some dredgers use a submersible pump mounted on a frame. Submersible pumps are usually used in combination with one or two submersible pumps located in the projectile body.

To raise and lower the soil intake device to the required depth, the lower part of the frame is suspended from the portal through a frame-lifting chain hoist.

To perform working movements, milling dredgers use only two bow side anchors and a pile device, which is installed in the aft end of the projectile body (see Fig. 7.12). A pile device of one design or another, using a working pile immersed in the bottom, fixes the corresponding point of the body in place. By winding and reeling in the ropes attached to the anchors, the dredger rotates around a fixed point, as a result of which the soil-collecting device moves along a circular arc.

On modern pile-anchor dredgers, the repositioning of side anchors is carried out using special cargo booms installed on the sides at the bow end of the hull. Operating papillon ropes are routed through blocks mounted on the frame of the soil intake device.

For periodic repositioning of each anchor, a lifting rope is permanently attached to its head, which is routed through the boom from a separate lifting winch.

The technological features of soil development using mechanical loosening agents are that their primary separation from the bottom is carried out by a mechanical loosening agent, and the suction of the resulting hydraulic mixture is carried out by a suction tip combined with the loosening agent in one soil intake unit.

The soil intake unit with a mechanical ripper of a modern dredger consists of a cutting element (cutter) with a drive, a suction soil receiver and the end section of the ripper frame.

Currently, milling rippers are most widely used. This is explained by their simplicity in design and operation and high efficiency in the development of various types of soils. In dredging practice, non-reversible milling rippers are most widely used. They are distinguished by the presence of knives with a one-sided cutting edge and therefore they can cut the soil only in one direction of rotation. Irreversible cutters are divided into open, closed and moldboard (Fig. 7.14).

Open cutters are distinguished by the presence of a completely or partially open frontal part of the cutter and consist of a hub, knives, spokes connecting the knives to the hub, and a support ring that provides spatial rigidity. Closed cutters are distinguished by the presence of cutting elements on the entire surface of their contact with the ground (including in the frontal part) and consist of a hub, curved knives and a support ring. Closed cutters have the blades closing forward at the hub. Moldboard cutters differ from other milling cutters by the presence of moldboard-guide surfaces that ensure forced movement of soil from the cutting area to the active suction area. Structurally, they consist of a hub, blades and a support ring. In moldboard cutters, there is no forward closing of the knives (as in closed cutters) and there are no spokes (as in open cutters), and the moldboard-guide surfaces interface directly with the hub.

7.4.2. Multi-scoop shells

Multi-scoop shells are effectively used in the development of cohesive and non-cohesive soils (clays, loams, sand with inclusions of stones). They are projectiles with a mechanical method of separating and lifting soil. The separation of soil from the bottom and its lifting in these dredgers is carried out by an endless scoop chain consisting of interconnected scoops. For most river multi-bucket shells, the excavated soil is transported to the dump site in soil hauling scows. Less often, the soil is removed to the dump along a long chute.

Multi-bucket scow projectile consists of a hull, a working body, a power plant and auxiliary ship devices (Fig. 7.15, 7.16).

The main working part of the projectile is the scoop chain, which is located in the front part of the body in its frame slot. The scoop chain goes around two drums - upper and lower. Upper drum

is the leading one, and the lower one is the guide. The scoop chain is driven by the upper drum, while the lower drum rotates idle and serves to direct the movement of the scoop chain. The upper drum is driven by an electric motor using a scoop drive, which is a set of gears. Rotation of the upper drum is transmitted from an electric motor through a gearbox using large gears mounted on the cantilever parts of the drum shaft. The scoop drive is located on the platform of the scoop tower.

The lower drum is mounted on the lower end of the scoop frame. To accommodate the drum, the end of the frame is made in the form of a fork, reinforced with sheets for strength.

The upper end of the scoop frame ends with a hole through which the frame suspension axis passes and is secured. On this axis the frame is suspended from the scoop tower. The lower end of the frame is suspended on cables from the frame-lifting frame and can be raised or lowered using a frame-lifting winch. The frame is equipped with roller ramps that support the rising part of the chain with scoops filled with soil from sagging. Thanks to their presence, chain friction is reduced as it moves along rollers rotating in the roller ramp bearings.

Cutting the soil with a scoop and filling it occurs when the scoop rotates relative to the axis of the lower drum. Under certain conditions
Soil cutting can also occur with scoops running at the bottom of the scoop chain bay, which cut into the ground under their own weight.

Scoops filled with soil rise to the upper drum, rotate with it and, when tipped over, are emptied into a soil well located inside the scoop tower. Depending on the position of the distribution valve, soil from the well is directed to the tray on the right or left side of the projectile. The soil rolls down the tray into the hold excavator scow, accelerated to the side of the projectile.

Typically, scows are loaded alternately from both sides of the projectile and they are changed without stopping the operation of the projectile.

The productivity of a multi-scoop projectile on the ground, m 3 / h, is determined by the formula

, (7.3)

Where: W h– scoop capacity, m3;

n h– the number of scoops passing through the upper drum per minute;

k n– coefficient of filling of scoops with soil;

k p– coefficient of soil loosening after filling the scoop.

The soil loosening coefficient in scoops is the coefficient of increase in the volume of soil loosened when filling the scoops. It is the ratio of the volume of soil in a loosened state (in a scoop) to the volume of soil with an undisturbed structure (at the bottom). The coefficient values depend on the type of soil: k p= 1.08÷1.28 for sand; 1.24÷1.30 – pebbles; 1.08÷1.17 – sandy loam; 1.30÷1.45 – clay.

Filling factor k n represents the ratio of the volume of soil in the scoop to the full geometric capacity of the scoop. The average value of the coefficient is 0.65÷0.80. When working on sticky clays, the filling of scoops can be reduced to 0.4–0.6 of their full geometric capacity.

River multi-bucket projectiles have a soil productivity of 100 to 500 m 3 /h and in number they make up about half of the entire dredging fleet. They are indispensable when developing rocky and clogged soils or the need to lay spoil dumps over long distances.

7.4.3. Single-scoop dredging equipment

On inland waterways, two types of single-scoop shells are used: rod And grab. They belong to machines of periodic (cyclic) action. The main soil-collecting device of single-scoop shells is a bucket or grab.

The cycle of single-scoop shells includes the following operations: installation of a bucket (grab) above the place of immersion in water; lowering the working element into the water; soil sampling from the bottom; lifting and turning the working body to the side; emptying the bucket (grab); reverse rotation of the working body to a new location for soil sampling.

Working device rod projectile(Fig. 7.17, 7.18) consists of a scoop-type soil-collecting bucket, a pile device and operational winches. The scooping device operates on the principle of an excavator with a straight shovel.

The main part of the projectile is the bucket, which is rigidly attached to the end of the rod, which is also called the bucket handle. The rod passes through the holder in the boom and rests on a special bearing. It can move and rotate using a pressure mechanism.

The boom is attached to a turntable, which is mounted on a base welded to the projectile deck. There is a turntable between the platform and the base. The upper end of the boom is held in working position by a guy rope attached to two inclined posts installed at the sides on the projectile deck. The inclined posts are held in place by cables.

The rotating platform is equipped with pressure, lifting and cargo winches, which are designed to change the reach of the rod, the depth of scooping and raising and lowering the bucket.

Changing the reach of the rod and the depth of digging is carried out by a pressure mechanism consisting of a winch, a system of ropes and blocks installed both on the rod and on the boom. The ropes of the pressure mechanism are retracted in such a way that, regardless of the position of the rod, the ropes always remain taut. This allows you to extend the handle when rotating the winch drum in one direction, and when rotating in the other direction, return the rod to its original position.

The bucket is lifted by a rope, one end of which is fixed to the drum of the lifting winch, and the other to the bucket. The bucket is emptied through a bottom that can be opened using a rope.

The work of the rod projectile occurs as follows. When the lifting winch drum rotates, the rod, under the influence of its own weight, rotates around a horizontal axis and takes a vertical position. In this position, the rod, under the action of the pressure mechanism and its own weight, drops to the bottom, and the bucket crashes into the ground. Then, by rotating the lifting winch drum, the rope attached to the bucket is selected. In this case, the bucket with the rod rotates around the axis of rotation and is filled with soil. The bucket rotates until the rod reaches a horizontal position. To reduce the heeling moment arising from the weight of the bucket with soil, the rod is moved back to the projectile body.

By turning the platform, the bucket moves to the place where it is unloaded into a scow moored to the side of the projectile, or to the place where the soil is dumped. To unload the bucket, the rod can, if necessary, be extended to the unloading point. To empty the bucket, its bottom is opened and soil is poured out of the bucket.

During soil extraction by a rod dredger, the horizontal component of the soil reaction is transmitted to the body of the projectile, tending to shift it in the direction opposite to the movement of the bucket. This component reaches a large value. Therefore, during operation, the rod projectile is held in place by two bow anchor piles and one thrust stern pile.

The projectile is moved along the slot to a new location for collecting soil using a bucket, which is carried forward using a pressure device and lowered to the bottom. Then the piles are raised and the body of the projectile is pulled forward by the pressure mechanism of the rod. After this, the soil collection process begins at a new location.

Sometimes the stern pile is installed on a trolley, which is moved using a running device along the slot of the housing. In this case, the forward feed is carried out by means of a rod and a thrust pile. The movement is carried out by pushing the projectile body away from the driven thrust pile using the running device of the trolley. In this case, the bow pier piles must be raised.

To move the projectile over a considerable distance, or to escape from the slot when ships are passing, operational winches installed on the deck are used, the ropes of which are secured to anchors.

The main advantage of rod projectiles is the ability to create large cutting forces, and therefore the ability to develop the most durable soils.

Significant advantage grab shells(Fig. 7.19, 7.20) is the ability to develop soil at great depths, inaccessible to other dredgers, as well as the ability to extract large stones and other large objects.

All mechanisms grab projectile mounted on a rotating platform. The lower end of the projectile boom is hingedly connected to the turntable, and the upper end is attached to the winch drum using a rope. When the winch drum rotates, the upper end of the boom, depending on the direction of rotation, rises or falls, changing the reach of the boom.

Rice. 7.19. Grab dredger

1 – ladle; 2 cable; 3 – boom; 4 – rotary mechanism; 5 – winch

Rice. 7.20. General view of the grab dredger

At the upper end of the boom there are blocks through which ropes pass with a suspended grab. The ends of these ropes are attached to the drums of two winches, with the help of which the grab is raised or lowered, and also opened and closed.

Unlike floating cranes intended for reloading operations, grab dredgers are equipped with means of operational movement, with the help of which orderly removal of the removed layer of soil is achieved over the entire dredged area. Grab shells also have a greater lifting capacity on the grab winches.

Grabs used in dredging operations are usually of two types: double-jaw and multi-jaw (petal). Double-jaw grabs are used when working on light soils, and petal grabs when working on heavy soils. Unlike grabs for handling bulk cargo, dredger grabs have a larger capacity and greater dead weight.

The process of extracting soil with a grab shell occurs as follows. The open grab is thrown to the bottom. Under the influence of its own weight, the grab's sharp edges crash into the ground. By tensioning the corresponding closing rope, the jaws of the grab are closed, separating the soil from the bottom. The grab filled with soil is lifted out of the water while the boom is rotated to the place of unloading into a scow or to the place of placement in a dump.

The hourly productivity of single-scoop shells on the ground, m 3 / h, is determined by the formula

, (7.4)

Where: W– bucket (grab) capacity, m3;

n e = 60/t c– number of working cycles per minute, ( t c– time of one cycle).

The productivity of domestic single-scoop shells ranges from 50 to 120 m 3 /h. They are intended mainly for the development of clay, pebble and rocky soils, heavily clogged soils, as well as rock removal work.

The main production characteristic of all types of dredgers is its technical performance, i.e. the performance achieved under optimal operating conditions.

The performance of dredgers under specific operating conditions on individual rifts may differ significantly from the technical performance as a result of the influence of a number of factors. Such factors are: the type of soil, the depth of its extraction, the thickness of the removed soil layer, the height and range of refilling, and the method of operation of the dredger. The influence of these factors on technical productivity Q t is taken into account in the work order for the development of a specific slot by introducing the calculated coefficient of utilization of technical productivity K r for these conditions. Then the calculated productivity of the projectiles, m 3 / h, is determined by the expression

The working time of the dredger, h, indicated in the work order, is determined by dividing the volume of excavated soil by the design productivity:

Where: W p– volume of soil to be extracted through the slot, m3.

Stops (downtime) during the operation of the dredger can be production or periodic. Ancillary production operations that require temporary cessation of dredger operation include:

Installation of the dredger at the work site and its assembly after completion of the development of the slot;

Repositioning of deadlift and side anchors;

Transition of the dredger from trench to trench;

Transfers of floating soil pipeline;

Re-pinning of piles;

Changing and waiting for soil hauling scows.

Periodic operations that also require stopping the operation of the dredger include

Change of soil intake and loosening devices;

Minor preventative repairs;

Cleaning of dirt paths when developing clogged soils;

Reception of fuel;

Passage of transport vessels.

To reduce dredge interruptions during production and periodic operations, it is recommended to use best practices to perform them without stopping work or to practice performing two or three operations simultaneously.

The purpose of the working equipment of the dredger is to destroy soil

that is, removing it from the face and forming a trench. There are following

current methods of destruction and transportation of soil: hydraulic

ski, mechanical, combined. The most effective is

the use of combined methods, for example mechanical destruction

grinding of soil and its hydraulic transportation from the face area.

Dredger (suction dredger)- a floating device for under-

water development of soils and extraction of non-metallic materials (sand, gra-

viya) from the bottom of reservoirs. The dredger is equipped with means for workers

movements, transportation of hydraulic mixture (pulp) along the slurry pipeline

I'll give you to the place of installation.

Dredgers are divided into the following types:

According to the working body - suction dredgers, ejector, auger, er-

According to working movements - anchor-cable, pile-cable,

pile and with the help of engines;

By type of soil ripper on dredgers, ejectors and airlifts

nyh – milling, hydraulic or milling-hydraulic

(auger, vibrating and other rippers are rarely used

According to the method of transporting soil - in its own hold

(hold dredger), through floating and onshore slurry pipelines,

along a suspended slurry pipeline, along a longculoir (long chute), in

scows, bunker barges;

By type of drive of the working body - diesel, diesel-electric,

electric diesel-hydraulic, diesel-electrohydraulic

personal.

Scope of application of dredgers:

Dredging;

Alluvium of dams, dikes and beaches;

Extraction of building materials and minerals;

Development of ash and slag storage facilities at thermal power plants;

Cleaning of canals, rivers and various reservoirs, industrial and

agricultural settling tanks;

development of underwater trenches for laying pipelines (du-

cores) and cables, as well as their washout;

Alluvium of roads and areas for industrial and civil construction

tel.

question number 20 option 4

1.As a traction means for pulling underwater pipes

of the pipeline, depending on the required traction force, we recommend

It is possible to use special traction winches of the LP series (the winch is

dragging), tractors equipped with winches, as well as similar

tractors working in a clutch.

Tractors should be used in the construction of small farms.

travel and traction forces up to 20–30 tons.

If tractors cannot move in the crossing area, then it is permissible

their movement along the shore with the block being secured on the shore

to change the direction of the traction cable.

2. When pulling a pipeline, if the traction power

funds are insufficient, you can use pipe layers to lift

ma of individual sections of the pipeline located onshore. For labor

pipelines with a diameter of less than 1020 mm cannot be applied to the pipeline

water additional pushing forces, with a diameter of 1020 mm or more

– the magnitude of the pushing forces and the need for their application should

be justified by calculations in the work project.

question number 20 option 5

The working bodies of underwater earth-moving machines are mechanisms that operate in an aggressive environment (water, soil, solid inclusions) with large dynamic loads. The requirements for the working parts must satisfy the conditions of normal operation of the machines.

Mechanical rippers are divided into the following groups: milling, rotary, rotary-bucket, screw, vibration, etc.

Rotary rippers are used to destroy overgrown plant soils (Fig. 87). The working bodies consist of drums with knives. Drums are discs on which knives are mounted.

Milling-hydraulic rippers are used to prevent sticking of cutters and increase the suction zone. On the cutter of such a ripper, hydraulic nozzles of the lateral, frontal and flushing types are installed (Fig. 88).

Rotary bucket rippers come with one or two rotors, with a hopper or a rotating suction pipe, and reversible.

Screw rippers are used to develop peat bogs and are replaceable equipment.

Silty and gravel-song soils are developed using vibrating soil sampling devices. Vibration drives are hydraulic and electric vibrators.’

question number 21 option 1

Rope-scraper installations can be used for development

trenches in swamps, construction of passages through small

rivers and reservoirs, as well as in mountainous areas on slopes of more than 20°

Scheme of operation of the rope-scraper installation:

a – with one bucket; b – with two buckets

Scheme of operation of LS-302 and LS-1001

The installation consists of a tractor (T-100 tractor), a two-drum

bed (L 51), mounted on the rear axle and towbar

tractor, a set of scraper buckets and an anchor device with

block. Such a device can be used with a hook

anchor supplied with the installation, buried in the ground or laid in

crossing the trench with logs or pipes, as well as a tractor

question number 21 option 2

Currently, the following methods for developing trans-

necks using excavators with a highly developed supporting surface:

single-bucket excavator TE-3M on wide tracks; one-

bucket excavator E-652B on slans, foam draggers and flatbeds

floating pontoons; marsh excavators MTP-71 (EO-4221) or

ECB; excavators TE-3M, MTP-71 (EO-4221) and EKB and some

Equipped with various types of replacement equipment, the excavator

TOR can perform the following types of work:

1) dragline - opening trenches and pits in swamps, swamps

deep floodplains of rivers, as well as rivers and reservoirs with a depth of no more than 0.9 m ;

2) with a grab – development of trenches and pits in swamps and rivers

and reservoirs with a water level height of more than 0.9 m. In this case, the excavator is

walks afloat, refraining from arbitrary movement or drift

with the current using a rope brace;

3) backhoe - opening trenches and pits in ordinary

ground conditions;

4) with a crane - hanging weighting loads on the pipe, production

loading and unloading and installation work in swamps, as well as fishing

the range of rivers and rivers with a water level height of no more than 0.9 m.

ensure the maneuverability and operation of the excavator in all swamps

types. Centralized tire inflation system with remote control

in the driver's cabin provides the necessary increase in pressure in

tires when moving and working on hard soils and reducing it

on marshy and soft soils.

question number 21 option 3

Ballasting and securing pipelines at design elevations

can be carried out in one of the following ways: by backfilling the pipe-

wires with mineral soil; concrete coating of the pipeline; mouth-

new to the pipeline of single reinforced concrete loads of various

structures; securing pipelines with anchor devices;

filling the internal cavity of the pipe with water, oil or petroleum

products (for oil pipelines and for oil product pipelines) (Fig. 8.5).

All balancing means can be divided into two main ones:

The first group includes devices that act on pipes

wire with its own weight:

a) single reinforced concrete loads;

b) group installation of single reinforced concrete loads;

c) single cast iron weights;

d) backfill mineral soil (usually used for increased

deepening of the pipeline);

e) fixed hydrophobized soils;

f) polymer-container ballasting devices (PKBU),

filled with local or imported soil or crushed stone;

g) mineral soil in a non-woven synthetic shell

materials;

h) continuous concrete coating of pipes;

i) anchor plates;

j) combined methods, etc.

The second group includes anchor devices with a load-bearing capacity

b) drop-down type;

c) fired;

d) explosive;

e) frozen;

f) cantilever type piles;

ability;

j) anchor injectors, etc.

question number 21 option 4

anchor devices, bearing capacity

the properties of which are determined by the properties of soils:

a) screw anchor devices (VAD);

b) drop-down type;

c) fired;

d) explosive;

e) frozen;

f) cantilever type piles;

g) anchor anchor devices;

h) gantry anchor devices;

i) screw anchor devices with increased retention

ability;

j) anchor injectors, etc.

question number 21 option 5

The screw anchor installation team consists of 6 people; VAG operator, drainage plant operator, bulldozer operator, electric welder, pipe-laying fitter and insulator. Screwing of anchors is usually done after laying the pipeline in a trench. Screwing of anchors into the ground can be done using lever devices manually or with special machines. The manual method of screwing anchors is highly labor-intensive and can only be recommended in special cases. Mechanization of securing a pipeline with anchor devices depends on their type, pipeline diameter and work conditions. The most widespread are screw anchors with a blade diameter of 150 - 500 mm, for screwing which machines such as VAG, MBTA, MZVK are used. Hydraulic anchor rotators VAG101, VAG203, VAG204 are attachments on tractors T-100 M or T-130 G, VAG201 - on the E304V excavator, VAG202 - on the T1224V or T1530V pipe layers, VAG205 - on the TDT-55 skidder. The working part of the machines is a rotator, consisting of a hydraulic motor and gearbox. Auxiliary equipment used when screwing in anchors includes the KT-1 trench caisson, used in flooded areas to secure the pipeline to the anchors with clamps, a set of KRG1 equipment with a mobile steam unit, or a D-563 steam converter for developing permafrost soils before screwing in the anchors. The load-bearing capacity of anchor devices is controlled by a DKA-351 dynamometer. The set of machines and equipment also includes an ASB1 or SDAU welding unit for welding anchors with a clamp and an ISTZB bitumen melting pot for applying a protective bitumen coating to the surface of the anchor clamps.

question number 26 option 1

The operating principle of control valves designed for

regulation of large expenses is to change their passage

strong ability when turning the disk in accordance with the input signal

cash coming from the control device (control

numerical machine, automatic regulator, remote control panel

control, etc.).

Electrically actuated shut-off valve:

1 – body; 2 – disk; 3 – shaft; 4 – axis; 5, 6 – supports; 7 – pressure flange;

8 – sealing rings; 9 – pin; 10 – rubber ring;

11 – clamping ring; 12 – manual override

question number 26 option 2

There are several types of pipeline shut-off actuators

fittings:

Electric drives;

Pneumohydraulic actuators;

Pneumatic actuators;

Hydraulic drives;

With mechanical gearbox.

question number 26 option 3

Check valves are classified as safety valves and serve to

preventing the reverse flow of the medium on the linear part of the pipeline

waters and thereby prevent an accident, for example, in the event of a sudden

stopping the pump. In Fig. Figure 13.14 shows a general view of the check valve.

It is an automatic self-acting safety

device. The gate is the main assembly of the check valve. He misses

medium in one direction and blocks its flow in the opposite direction. Valve-

We are not shut-off valves.

Rotary check valve DN 50–600 mm

question number 26 option 4

To protect vessels of devices, tanks, pipelines and other

technological equipment from destruction due to excessive exceed-

To control pressure, safety valves are most often used.

If the pressure in the system increases above the permissible safety limit,

The valve automatically opens and releases the necessary

excess working environment, thereby preventing the possibility of an accident. By-

after the end of the release, the pressure decreases to a value less than the beginning

when the valve is triggered, the safety valve automatically closes

is closed and remains closed until the system again increases

The pressure is higher than permissible. In Fig. 13.15 shows the cargo pre-

safety valve. Safety valves are designed

for liquid and gaseous, chemical or petroleum working media,

The tightness standards in the valve must satisfy GOST 9789–75.

Load safety valve

question number 26 option 5

Scheme

Ball valve

Tap is a locking device consisting of a body and a plug, in

in which the plug has the shape of a body of rotation with a hole for passage

liquid or gas. In Fig. 13.8 shows a diagram of a ball valve

electric porno. The plug rotates around its axis.

In Fig. Figure 13.9 shows the seal of the valve plug.

Crane diagrams:

a – conical; b – cylindrical; c – spherical;

1 – body; 2 – plug; 3 – separating washer; 4 – stuffing box;

5 – stuffing box; 6 – shank

Cranes are also classified according to other design applications.

signs, for example, according to the method of creating specific pressure on the seal-

surfaces, according to the shape of the plug passage window, according to the number of passages

dov, by the presence or absence of passage narrowing, by type of control

and drive, according to the material of sealing surfaces, etc.

(Fig. 13.11).

Advantages of cranes:

Low hydraulic resistance;

Directness;

Simplicity of design;

Small overall dimensions and weight;

High strength and rigidity;

Reliable sealing;

Independence from the direction of movement of the medium;

Ability to regulate pressure and flow.

Each type of crane has its own disadvantages and advantages,

very necessary

Hydraulic work related to soil extraction or mining requires the use of special equipment. Such equipment includes a suction dredger. The effective operation of a dredger on a river or other body of water directly depends on knowledge of the principles of its operation and operational characteristics.

What is a dredger

A dredger is a watercraft whose purpose is to pump eroded soil (pulp) using a powerful pump through a pipeline to a specified distance - into the hold or to the shore. The vessel is equipped with the necessary equipment for the work and can be used for:

cleaning reservoirs from bottom sediments, as well as for their deepening;
reclamation of dams, dikes and beaches, roads and squares during construction;
extraction of sand, gravel, sapropel, precious metals;
cleaning settling tanks of industrial and agricultural enterprises;
development of ash and slag storage facilities for enterprises of the coal, coke, metallurgical, and mining industries;
laying trenches for pipelines and trenches with their subsequent washout.

What else is a dredger needed for? Special equipment may be needed when eliminating the consequences of a flood, constructing sea and river ports, strengthening the coast, protective dams and other significant hydraulic facilities.

Dredger device

Considering the design of hydraulic equipment, we can distinguish several groups of devices according to their functionality.

What does a dredger consist of:

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

The dredger drawing clearly shows its design diagram:

How does a dredger work?

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

The operating principle of a dredger for cleaning reservoirs is as follows:

after preliminary calculations of the mixture supply speed and the permeability 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 this, air is pumped out of the suction pipe;
the resulting vacuum draws water and soil particles inside;
the slurry enters the pump and is pumped to shore (cargo barge);
the movement of the entire system is carried out using a pile drive or winches (a combination is possible).

General control is carried out from the dredger's cabin, where there is a remote control with access to all 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 dredgers determine the range of tasks that can be implemented. These indicators include:

productivity - this figure can be from 1 m³/h (for mini-equipment used on private farms) to 5000 m³/h on hard soil, 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) for frequent movements;
the size of structural components - this indicator is important if frequent transfers of equipment are necessary.

It is worth taking into account the expected depth of development, flow speed, and environment of use (salty, alkaline, fresh).

Types of dredgers

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-dismountable;
according to the method of soil collection: with or without preliminary loosening;
by method of movement: non-self-propelled and self-propelled;
by control method: with manual, remote, automatic control.

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