If there are at least 1-2 large cable manufacturers in your area, then the idea of ​​​​opening a cable drum production may be suitable for you. Although not only manufacturers need cable drums. Exists a large number of cable bases where the cable is cut and rewound. They all need cable reels to transport cable and wire. Here is what they say on the forums (homeidea.ru):

Cable drums or, as they are also called, cable reels, are used for winding, transporting and storing cable products. Produced from 5 to 22 sizes. For cable drums, GOST 5151-79 "Wooden drums for electric cables and wires" is installed.

Cable drums are needed, first of all, by those who produce cable products. There is an offer on the market, but often wooden drums are not of very good quality, made in garage conditions, on old equipment from the 80s and 90s. If you can offer a better product, then you will always have a buyer. The wholesale price for size 8 wooden cable drums starts from 800 rubles, for size 22 - from 2500 rubles apiece. In fact, even a small workshop with 6 workers can produce up to 15 cable drums per shift. The monthly turnover of such a micro-enterprise will be at least 400 thousand rubles. In addition, the company can also produce other wood products, such as wooden pallets.

It is advantageous to place production where there is a sufficient raw material base: logging enterprises, sawmills. Cable drums are a fairly large product, so its production requires sufficient production and storage facilities. An example business structure looks like this:

• production workshop - from 150 sq. m;
• repair and mechanical workshop - from 50 sq. m;
• warehouse - from 100 sq. m;
• office and staff premises - from 20 sq.m;
• shower room and bathroom - from 8 sq.m.

Must have central water supply and sewerage. A heated room is required for year-round production. Thus, it will be necessary to rent production space from 300 sq. m. Depending on the region, the monthly rent will cost from 80 thousand rubles.

The main costs at the start of the business will go to the purchase of equipment. In the equipment market for the production of cable drums, manual and automatic lines are distinguished. If you want to save money at the start, then take b. y. hand lines. A full-fledged production can be opened with an amount of up to 5 million rubles. At the same time, get ready for the fact that you will have to create a staff of 15-20 people who will be directly employed in production. One worker for an 8-hour shift can produce 2-3 drums. Accordingly, to produce 50 drums per shift, 25 people will be required. As an example, the words of the user "Roman Valerievich" from the professional forest industry forum wood.ru:

The purchase of automatic equipment, a line for the production of cable drums, will cost several times more than manual equipment. We are talking about amounts of 10 million rubles or more. On the other hand, automation will make it possible to produce a better product, where the likelihood of defects inherent in manual production is minimized. In addition, the need to hire a large number of workers is significantly reduced, which significantly reduces and fixed costs related to payment wages. Hence, the cost of production will be lower, and there will be additional scope for setting prices for products. The product will be more competitive.

The most reliable lines for the production of cable drums are made in Spain and Italy. For example, the machining center "Bobimatic" for cable drums (Spain):

Such an apparatus cuts a circle (bobbin) from a hammered shield, chamfers, mills the neck circle, drills holes for bushings and studs, and cuts a concentric neck groove.

The Italian Corali lines are even more functional and include a nailing machine, a hole drilling machine, a molding and milling machine, a cleaning section, a mechanical stacker, a chain conveyor. This line makes it possible to produce drums with cheek sizes from 600 to 1250 mm, from 1000 to 2500 mm. The line can serve only 4-6 people. And its productivity is at least 800 finished products per shift.

There is another option for organizing such a business - buying finished production. For example, Avito has offers for 11 million rubles:

The advantage of this option is that you get a ready-made working model with an accumulated client base. Buy and get income. Another question is how profitable this production is, and whether it is profitable at all ...

Despite the range of pumping equipment presented to us by progress for pumping water from underground sources, many well owners are true to tradition and use a classic drum for this purpose. In specialized stores, you can buy ready-made models, but it’s easy to assemble such a design yourself. Consider how to make a drum for a well with your own hands, what materials will be required for this and what gate options can be made at home.

For many centuries, water from a well shaft was traditionally raised using a cylinder rotating on an axis, one end of which serves as a handle. During the movement of the structure, a chain or rope is wound around it, lifting the filled bucket. The drum for the well is installed above the shaft on two racks attached to the ground part.

There are 3 types of gates:

• wood;
• metal;
• combined (from wood and metal parts).

The most popular is combined, so we will further consider the algorithm for manufacturing a combined gate.

A well with a drum has come down to us from the abyss of centuries and continues to be popular

Interestingly, in terms of frequency of use, the drum is still in the lead - the owners of wells, like centuries earlier, use it to raise water, despite the existing alternatives ("crane" and pumping systems). Even if water is pumped from the mine, some summer residents use a crank as a safety net in case of equipment malfunction or power outage.

Ways of attaching the drum to the well shaft

The collar can be attached to the shaft in two ways:

• on racks fixed on the base of the shaft (supports are installed either during the construction of the well itself, or mounted on a finished foundation);
• on racks resting on a tabletop or “belt” of reinforcement (attached to anchors).

Before you make a drum for a well with your own hands, decide on the materials from which you will make not only the cylinder itself, but also auxiliary elements. For the manufacture of supports, brick, wood or metal are chosen - depending on the material of the well house and the expected loads on the structure.

A gate with a house will protect the mine from dust and other debris

Note: the drum for the well will not only help to extract life-giving moisture from the depths of the soil - it provides additional reinforcement of its above-ground part and prevents debris from entering the mine.

Making a gate for a well step by step

Before starting work, prepare consumables and auxiliary materials:

1. A cylindrical wooden base 20-25 cm thick. It should be shorter than the diameter of the well shaft (the gap between the supports is 4-5 cm on each side) for free movement during operation. Usually a length of 1.2 m is enough, but the calculations are individual.
2. Two channels, logs or bars 200-200 mm for racks.
3. Metal sheet (50x50 mm) from 3 mm thick. Stainless steel will ensure the durability of the product.
4. Metal rod for the axis and handle of the drum.
5. A chain or cable for lifting the bucket (the length should be sufficient to reach the bucket water level in the well, preferably with a margin).
6. Welding machine.
7. Drill for working with metal and wood parts.
8. Bulgarian for cutting iron elements.
9. Planer or sandpaper for sanding wood.
10. Nails or self-tapping screws, a metal bracket plus anchors, if you plan to mount the structure on the “armor belt”.
11. Roulette, compasses, pencil and ruler for marking and measuring.

Log requirements. Choose hardwoods - pear, cherry, beech or willow. The beech will last for decades, but it is heavy - take this into account when calculating. Before work, debark the log, sand it and treat it with a water-repellent impregnation to protect against wear, swelling from contact with water and mold.

By choosing a wide log, you will simplify the use of the well

Remember: The larger the diameter of the deck, the faster the chain will wind up - the fewer turns it will take to raise a bucket of water.

Important: It is useless to open the log with varnish - after a couple of times using the drum, the coating will break off from the winding of the chain or cable and fall into the well.

Preparatory work

To make a drum for a well, you need to place an axis - an iron rod - in a wooden deck. To do this, the log is wedged, a hollow is made in the center for reinforcement and the deck is fastened with metal brackets. It is also possible to perform through drilling under the axle. But these are time-consuming and difficult to do at home methods, we suggest doing it easier:

Before starting work, make calculations and draw up drawings

1. Make a project drawing with calculations.
2. Mark the center at the ends of the deck.

Before drilling the ends, mark their center with a ruler or compass

1. Using a drill at the ends of the deck, make indentations of 12-15 cm. Their diameter should be slightly less than the diameter of the axis.
2. Mark the iron rod with a margin for the handle and cut it with a grinder into 2 parts: one is slightly longer than the recess in the deck (about 20 cm), the second fragment, from which you will make the handle, should be longer (about 1 m). If the handle is attached to the axis separately, just leave a couple of cm in reserve to fix the elements.
3. With a compass, draw circles on the iron sheet, equal in diameter to the circumference of the log, and cut them out with a grinder. Drill holes in the center of each for the axles.

Cut out circles from a sheet of metal

1. At a distance of 1.5-2 cm from the edges of the circles, we drill holes for nails or mark places for screwing screws.
2. Mark the sheet again and cut out two strips. Weld them into hoops-staples 5-6 cm wide. They will fix the log, preventing it from cracking over time.
3. If the racks have not been installed before, we make them from channels or prepared bars. We mark holes for the axle on them and in the first case we burn them welding machine, in the second - we drill with a feather nozzle of a drill.

You can fasten the gate to the uprights on a sleeve with a bearing or through.

Help: if it was not at hand sheet metal, for disks at the ends of the future gate, you can use rectangular pieces of iron. A wooden deck can be replaced with a large diameter pipe - this point must be considered before proceeding with the manufacture of the gate.

Choice of rack material

For trouble-free operation of a drum with metal axes, it is better to make racks from wood. Rotation will be smooth if the holes in the support bars are lubricated to reduce friction and prevent abrasion of the wood surface.

If you use a bushing and drill holes in the racks larger than those of the axles, this will increase the life of the support units and minimize friction.

Bushings can be replaced with ball bearings. To implement such a system in the supports, it is necessary to make hubs for a press fit of the axles in the outer cage and provide oilers for lubrication.

Algorithm for assembling a drum for a well

We insert segments of rods into the recesses at the ends of the deck.

We place circles on top, weld to the axes.

If you want to immediately weld the discs to the axles, provide a groove instead of a hole in one of the racks; otherwise, after fastening these parts of the gate, you can no longer install

We put hoops on the ends of the drum.

Important: The hoops must be put on before fixing the disks with nails in order to protect the wooden blank from cracking and deformation.

We fix metal disks on the ends of the gate with nails or self-tapping screws.

Using a bracket in the center of the workpiece, we mount a bucket chain or cable.

We install and fasten the racks to the aerial part of the well with anchors.

We insert the drum into the racks, making sure that it is placed right in the center, symmetrically.

Important! If you immediately weld the circles to the rods on both sides of the deck, in one of the racks, instead of a hole, you need to make a hollow so that the long part of the rod can lie in it. If a through fastening is planned, then first we insert a short rod with a disk welded to it into the log, put on a hoop and thread it into the rack. Then we put the hoop on the other end and, holding the workpiece and the second disk, thread the long axis through the hole in the second rack and only then (!) Weld it to the iron circle.

We bend the long bar twice by 90 ° (the first time - vertically, the second - horizontally, so that the handle is parallel to the gate). At will, we decorate or supply with a wooden handle for convenience.

Make sure the handle is long enough

Please note: The longer the middle part of the handle, the less effort will be required to raise the water. But its upper part should not rise too high during a full turn to make it convenient to operate the drum. In order not to miscalculate, mark on the drawings the desired height relative to the axis of rotation of the crank.

It remains to hang a bucket on the chain - and you're done.

After mounting the structure, treat the metal elements with anti-corrosion impregnations.

To protect the mine from dust and make the structure more effective, in addition to the drum, you can make a house for the well with your own hands.

No templates: non-standard solutions

We gave an example of the simplest typical version of a drum for a well, but craftsmen make more intricate designs with their own hands. You can turn an ordinary gate into a spectacular exterior element by decorating a deck with carvings, or use non-standard design solutions:

• several thin logs instead of one - a cylindrical textured gate;
• a disk mounted on a pipe of a suitable section is an option with urban notes;
• rack and pinion, fixed on stiffeners (on wooden disks) - the motives of rustic comfort.

The handle can also be designed creatively - instead of rods, use painted pipes filled with sand for density, a steering wheel, a bicycle pedal, a car steering wheel. Let your imagination run wild.

Don't be afraid to experiment with design

Making a gate for a well with your own hands is easy if you have patience and spare no time for accurate calculations and careful preparation. But if you are not sure about end result 100%, seek help from professional carpenters or purchase a ready-made design

The drum is the oldest percussion instrument. It is believed that they were first used by the inhabitants of Mesopotamia. A little later they appeared in Ancient Egypt and Sumer. Drums were an integral part of mysterious rituals, religious rites and ritual dances. At that time, they were made from solid wooden log cabins, hollow inside, and animal skin membranes. Now the process of creating drums, as well as the materials used, have improved, which has made it possible to mass-produce these instruments. The need for street military bands to perform indoors initiated the invention of the drum set. The parts that were performed by three musicians, thanks to the drum kit, were combined into one!

Now the body of the drum is made of multi-layered thin maple boards of a certain width, fastened by the so-called lamination, or made of metal. The sound of a multi-layered drum is more booming compared to an instrument made from a solid log of wood, and the sound of a metal drum is sharper and louder, unlike a wooden drum. In the case of metal, the body of the drum is cast from a liquid alloy of copper and tin. Next, the case is ground and polished, achieving a perfectly smooth surface. With the help of a robotic drill, holes are drilled in the body for attaching various parts of the future drum and for setting its volume. Then the edges of the cylindrical workpiece are cut to an angle of 45 degrees. Holes and recesses in the body are ground and polished by hand. To make the tool last as long as possible, it is covered with a protective varnish. During the assembly process, tensioners are inserted into the drilled holes, which control the tension of the membrane. Further, in the case of manufacturing a snare drum set, a mechanism is attached that allows you to switch sound modes and play with or without strings. The membranes are fixed with chrome hoops. They are made of very durable polyester, which, unlike genuine leather, is not sensitive to changes in temperature and humidity. The bottom membrane, made of transparent polyester film, is much thinner than the top one and quickly transfers the sound to the strings. Drum strings are made of copper, steel or brass. They are pulled parallel to the bottom membrane and connected to a tension controller.

For a louder sound, there is a bass drum. It has a slightly different shape, and the membrane is stretched in such a way as to produce lower sounds. The production of each drum is completed with an inspection, tuning and sound check.

If you would like to learn how to play them, come to music school Jam's cool. Here you can not only master the drum kit from scratch and develop a sense of rhythm, but also get the experience of playing as part of a real musical group.

The drum of a steam boiler with natural circulation, as well as the bodies of steam generators and heat exchangers, is a closed cylindrical vessel with spherical or elliptical bottoms with manholes.

According to the method of manufacture, cases and drums can be divided into several types:
1. welded vessels;
2. forged vessels.

The use of forged vessels is very limited due to the large amount of metal waste. Sometimes forged bodies are made for reactors and steam generators of nuclear power plants.

Consider the production of welded vessels. Let's first present the 5 main types of vessels:
1. vessels with a cylindrical part made from one sheet, the shell is made by rolling and has one longitudinal seam;
2. vessels, the cylindrical part of which consists of two half-shells (troughs) welded together;
3. vessels, the cylindrical part of which consists of several shells connected by transverse seams, with each shell having one or two longitudinal seams made before the shells are assembled in the cylindrical part;
4. vessels consisting of two forged halves with crimped bottoms, the halves of the vessel are connected by one annular seam;
5. Forged vessels made from one forging.

The cylindrical part of the drum can be made with longitudinal and transverse (annular) welds. Number of longitudinal and transverse welds is determined by the diameter and length of the drum, as well as the possibility of obtaining a boiler sheet of maximum length and width.

The inner diameter of the drum is generally between 900 and 1800 mm. The wall thickness of the drum reaches 115 mm at a pressure in the drum of 156 atm. The length of the drum corresponds to the length of the front of the boiler and reaches 20 meters or more.

The weight of such a drum is more than 100 tons. To enable penetration into the drum, both bottoms have access holes either oval in size 400 × 325 mm or round in diameter 400 mm. The cylindrical part of the drum has a large number of holes, to which various pipes of the boiler are connected by means of fittings.

The drum is the most important part of a natural circulation boiler. The boiler is fed with water through the drum, the steam-water mixture from the boiler is collected here and the separation (separation) of steam from water takes place. From here, the steam goes to the superheater for superheating. To separate steam from water and clean it inside the drum, various intra-drum devices are mounted.

Requirements for boiler sheets

For the manufacture of welded drums, a boiler room of calm sheet steel, smelted by an open-hearth method or in electric furnaces, is used by the Gosgortekhnadzor. The requirements for boiler steel sheets are very high. Boiler sheets are made from ingots or slabs.

A slab is a thick-walled repeatedly rolled ingot with a length to width ratio of less than three. As a result of rolling, the cast structure is destroyed, the metal becomes denser and more uniform, as the crystals are reoriented.

Sheets are supplied cut on four sides. The cutting of the edges of the sheets is carried out by the fire method. After rolling and flame cutting, the sheets are subjected to high tempering.

The boiler sheet sent from the supplying factory must have a certificate stating:
1 - name or trademark supplier plant;
2 - sheet designation according to the standard;
3 - chemical composition;
4 - melting number;
5 - rental number;
6 - results of mechanical tests and metallographic studies;
7 - type of heat treatment;
8 - parameters of the actually carried out heat treatment mode;
9 - weight and size of the sheet;
10 - conclusion of the quality control department on the full compliance of the sheet with the requirements of the RM.
On the sheet itself outside the post-processing zone, across the rolling on the front side, marking should be applied: sheet designation according to the standard, melt number, rolled product number and quality control stamp.

Input control

To improve reliability at boiler plants, before supplying raw materials and semi-finished products to production, they always carry out an input control of the incoming sheet. Incoming inspection serves as an additional barrier to defective products and detects defects missed at supplier factories or arising from careless transportation and storage.

The requirements for incoming inspection at boiler plants are no different from the requirements for manufacturing plants. However, it should be taken into account that the input control is a repeated control - an additional operation leading to an increase in the cost of the product.

Typically, input control consists of the following operations:
. documentation checks;
. external examination and measurement;
. tests to determine chemical composition, mechanical properties and metallographic characteristics;
. checking the quality of the material by non-destructive control methods.

Before launching the sheet into production, it is mandatory to check the availability of accompanying certificates, completeness necessary information in them and their compliance with the requirements specifications and GOSTs.

Boiler sheets are not allowed to be produced without a certificate and a seal.

Despite the primitiveness of external examination, it allows rejecting sheets with the most severe defects.
During the external examination, each sheet is checked. on the outer surface and the edges of the sheet should not have scale, cracks, deep scratches, captivity, sunsets, slag inclusions and delaminations. The presence of markings and hallmarks of the supplier plant is checked. The sheet is measured in length, width and thickness.

During transportation, warehousing and storage of materials, there may be cases when sheets different brands steels are in one place, and their marking has been erased. Chemical and spectral analyzes are used to determine the steel grade. Preference is given to spectral analysis, as it is faster and more accurate. One of the types of spectral analysis is steeloscopy. All sheets of alloy steels (type 16GNMA) are subjected to steeloscopy to determine the presence of alloying elements, after which the steeloscopist puts a stamp on the checked sheet. The results of steeloscopy are recorded in the boiler passport.

Sheets of steel grades 16GNMA and 22K with a thickness of 60 mm or more for the manufacture of drums and other pressure vessels (10 MPa), after checking the certificate data of external examination and measurement, are subjected to ultrasonic flaw detection on a checkerboard grid 1 with cell sizes of 200 × 200 mm and throughout the perimeter of sheet 2 with a field width from the edges of 200 mm.

Ultrasonic testing makes it possible to detect delaminations, shell cracks and gas pores in the thickness of the metal. The advantage of this method lies in the simplicity, speed and reliability of control, as well as in the absence of the need for special premises and expensive equipment.

Sheet editing

Sheets intended for the manufacture of drums often have deviations from flat shape. For sheet steel, the gap between the ruler, placed on the edge, and the surface of the controlled sheet should be no more than:
in the direction along the rolling for sheets with a thickness of 4-8 mm -2 mm;
for sheets with a thickness of 2.20 mm -1.5 mm;
for sheets with a thickness of more than 20 mm - 1 mm;
across rolling - no more than 1 mm.

In the manufacture of welded drums, the straightening of sheets and the processing of their edges are of great importance, since a good quality welded joint can only be obtained with well-straightened sheets and, therefore, with correctly processed edges.

Machine straightening of metal is carried out on straightening machines.
1-guide rolls; 2 - upper straightening rolls; 3 - lower straightening rolls.

Multi-roll sheet straightening machines are designed for straightening sheet metal. Under the action of friction, the sheet is drawn in and passed between two rows of regular rolls arranged in a checkerboard pattern. Each section of the sheet perceives alternating multiple bends in opposite directions, with stresses exceeding the yield strength of the sheet material. As a result, the irregularities present on the sheet are eliminated, and the sheet exits the machine flat or with a slight uniform curvature along its entire length.

The thinner the sheet and the harder the sheet material, the more difficult it is to straighten and the greater the number of rolls in the machine must be. Machines with 7-11 straightening rolls are most widely used in steam generator building.

The work on the straightening machine is carried out as follows: the edge of the sheet to be straightened is led between the rolls. Then the entire row of upper rolls is lowered to a position in which the bend of the sheet necessary for straightening is created. After that, the rotation of the rolls is turned on, and after five or six reciprocating movements of the sheet in the machine, the sheet is straightened. Changing the direction of movement of the rolls is carried out using a reversible electric motor.

Since the sheet undergoes plastic deformation, in which the stresses in the metal exceed the yield strength, and hardening of the metal occurs, after straightening to remove the hardening, the sheet is in some cases annealed.

It should be noted that, as a rule, sheets thinner than 16 mm are subjected to editing. thicker sheets, which are heated before bending, straighten out during the bending process.
After editing, the sheets are sent for marking.

markup

In the mass production of parts from sheet metal, they can be cut without preliminary marking, along the stops. Usually markup is a necessary operation.

Marking is used to define the contour of a cut or machined part, to determine the location and size of internal cutouts, the location of hole centers, chamfer sizes, bending and machining boundaries, and in some cases to indicate the base planes of parts.

The manufacture of half-shells and bottoms begins with marking the sheet for cutting blanks, which is not difficult and is performed using a ruler, compass, core and hammer.
An important circumstance! According to the conditions for assembling the vessel for electric welding, it is necessary to observe the transverse dimensions of the cylindrical part of the vessel and the bottoms with such accuracy that should ensure the shift of the edges at the junction of the cylindrical part with the bottom by no more than 0.1 of the vessel wall thickness. Therefore, domestic boiler plants adopted a system for manufacturing the cylindrical part of vessels with S≤45 mm according to the actual diameter of the bottom, measured in a cold state. This requirement is eliminated in the manufacture of thick-walled vessels (S> 45 mm), since in this case the joined edges of the shells and bottoms are machined to the specified dimensions.

The operation of marking a sheet for a shell or trough is performed according to the cutting chart, depending on the shell manufacturing technology. In the case of a shell made of two troughs by stamping or sequential bending on a press, the semi-shell blank 1 is a rectangle with two curly end sides.

The last four protrusions 2 (two on each side) serve to transport the workpiece and the stamped half-shell; in addition, they are input and output strips for electroslag welding of longitudinal seams and places for installing small assembly brackets, the middle protrusion 3 is necessary for installing a powerful technological assembly bracket when assembling two half-shells into a shell. All these protrusions are technological and, as the shell is made, they are removed by gas cutting.

The correctness of the markup is checked by the Quality Control Department of the plant, and if the deviations from the dimensions do not exceed 5 mm (with a length of up to 10 m) and 10 mm (with a length of more than 10 m), and the difference in the diagonals of the marked rectangle does not exceed 5 mm, the sheets are fed for cutting.

The blank for the bottom is a flat round disk. On a steel sheet with a thickness equal to the thickness of the bottom wall, a center punch marks a point in the center of the circle for the leg of the compass. The diameter of the workpiece is determined by the calculation formulas according to GOST 6533-78. If there is a manhole in the bottom, then it is marked for preliminary cutting, and the major axis of the manhole is perpendicular to the direction of the fibers in the sheet.

When marking, allowances for linear shortenings from welding must be taken into account and they must be indicated in the technological documentation.

In the middle part of each billet marked on the sheet for stamping bottoms and shells (or for rolling) across rolling, outside the zone of subsequent processing, a marking is applied indicating:
sign of the sheet supplier;
steel grades;
heat numbers;
sheet numbers;
serial number of the workpiece;
bottom diameter and sheet thickness;
drawing designations.

Note: the last three points for boilers with a pressure of less than 4 MPa can be omitted in the marking.

metal cutting

In the manufacture of steam generator parts, two cutting methods are used:
. mechanical;
. fire or gas.

For sheet cutting purposes, oxy-fuel metal cutting is widely used. This cutting method is based on the ability of iron to burn at 1300-1350 C in a sufficiently strong and properly directed oxygen jet so quickly that the places adjacent to the combustion strip do not have time to heat up significantly. Gas cutting can be done manually, semi-automatically and automatically.

For automatic cutting, stationary gas-cutting installations are used, equipped with special tables for laying sheets for cutting. During the cutting process, the sheet remains stationary, and the cutter (or cutter block) moves along the cut line.

Manufacture of shells and half-shells

Shells are made by rolling a steel sheet on bending rollers or stamping it, followed by assembly and welding of half-shells (troughs) into a shell.

When making shells by rolling, two options for their manufacture are possible:
. shell rolling;
. rolling half-shells with subsequent assembly and welding into the shell.

For rolling, three-roll or four-roll bending rolls are used. Depending on the power of the rollers, bending is carried out cold or hot. With large radii of curvature, the sheets are rolled in a cold state, with small radii - in a hot state.

The process of bending sheets on rollers is associated with such deformations of the sheet under the action of external forces, in which the outer fibers of the sheet are lengthened, and the inner ones are shortened. The neutral line passing through the middle of the sheet thickness remains unchanged during the bending process.

When bending on three-roll rolls, it is impossible to obtain the correct cylindrical shape shells - straight sections remain. The need to have, in the case of using three-roll rollers, also a press brake limits their use in the production of boiler drums. On the contrary, the possibility of bending edges in sheets on four-roll rollers has led to their widespread use.

The bending of sheets by the rolling method consists of the following operations: installing a sheet with turned edges into the rollers, bending the sheet into a trough or shell and removing them from the rollers.

The process of bending (deformation) of the sheet begins with the moment of rotation of the rolls and the lowering of the upper roll 3 on the three-roll sheet-bending rolls or the simultaneous lifting of the side rolls 4 on the four-roll rolls.

Rolling of the shell or trough 2 is carried out in one or more passes of the sheet in the rolls 1,3,4 during which the sheet performs a reciprocating motion by changing the direction of rotation of the work rolls; lower 4 in three-roll rollers and lower 1 in four-roll rollers.

On rollers, shells are made with a restriction on the minimum diameter, sheet thickness and length:
. the minimum diameter of the shell is 1.25 of the diameter of the upper roll;
. the greatest wall thickness - 90 mm;
. the length of the shell is not more than 3 m.

Thick-walled sheets are hot-bent Sheets are heated up to 950-1100 C in special sheet-heating furnaces with a bogie hearth.

During the heating process, the temperature must be carefully monitored. The duration of heating, depending on the material and thickness of the sheets, their size and quantity is 2-4 hours.

Edge liner in sheets

The essence of edging lies in the fact that before bending the sheet into a cylinder or trough, the edges of the sheet, forming a longitudinal joint, are bent to a given radius of curvature. Otherwise, the rolled shell will not have a cylindrical shape due to the remaining non-rolled ends a.

This happens because when bending in the rollers, the end section of the sheet a remains almost flat; the width of this section is approximately half the distance between the centers of the lower rolls.

On three-roll rollers, the width of the flat section is 150-200 mm. When bending sheets in four-roll rollers, the flat area ranges from S to 2S, depending on the length of the bent edge (S is the sheet thickness).

The importance of the edging operation in sheets before rolling is determined by the fact that it guarantees the correct cylindrical shape of the drum; the latter is prerequisite to ensure high quality welding.

To obtain the correct cutting of the joint for welding, the ends of a straight sheet are subjected to mechanical or fire treatment according to templates.

When rolling a sheet with edged edges, the sheet will be given the correct cylindrical shape.

Edge stitching methods:
1. Bending the ends of the sheet in cold and hot condition under a hydraulic bending press (I - initial stage of edging, II - final stage of edging; 1-punch, 2 - matrix, 3 - sheet).
2. Bending of sheet ends in cold and hot condition in four-roll plate bending rolls.

Bending the ends of the sheet under a press brake
3. Pressing the ends of the sheet into the bending die, which is mounted on the lower rolls of the three-roll sheet bending rolls.

Sheet edging in four-roll rolls, 1 - bottom roll, 2 and 5 - side rolls, 3 - top roll, 4 - sheet

Edge liner by pressing the end of the sheet into the folding matrix,
1 - matrix, 2 - upper roll, 3 - sheet, 4 - lower rolls

Progressive is the method of manufacturing shells from two half-shells.

Half-shells (troughs) for subsequent assembly into a shell are made on a hydraulic press:
. method of stamping in a closed die;
. method of sequential bending in an open die (universal bending method).

Stamping and bending of half-shells is carried out hot.
Heating of blanks is carried out in heating furnaces with a sliding hearth. Several workpieces are placed on the extended underlay through the gaskets. In order to reduce metal scale formation, the furnace is preheated to a temperature of 700-800 C. The semi-shell blank for stamping is heated to a temperature of 950 C.

The heated billet is fed onto the die die and centered. Preliminarily, the workpiece is bent to half the height of the half-shell, carefully removing scale from the workpiece and die with compressed air. After that, the traverse of the press is lowered and the final stamping of the half-shell is performed.

For stamping half-shells of different diameters or wall thicknesses, various dies are required, the manufacture of which is rather complicated and expensive. A more versatile method that does not require expensive dies is the method of manufacturing sequentially flexible half-shells in an open die.

By bending on a hydraulic press, mainly half-shells (troughs) are made for high-pressure welded drums with a wall thickness of up to 100 mm or more. Each of the shells that make up the cylindrical part of the drum is welded from two identical half-shells - troughs, bent in a hot state on a hydraulic bending press.

Bending is performed using a simple universal stamp, consisting of a punch a and two support pads b, mounted on the table of the bending press, the pusher of the manipulator c.

The technology of bending a half-shell on a bending press includes a series of successive transitions carried out in several press strokes.

On a universal matrix, a universal punch at a distance of 100 mm from the edge makes the first bend of the sheet. Closer to the edge, bending is technically impossible. After bending, the edges of the half-shell remain unbent, with a width slightly less than the distance between the support blocks. Therefore, the width of the workpiece is taken with an allowance per side equal to two to four times the thickness of the sheet. After bending, the straight edges of the half-shell are cut off.
For bending half-shells in the hot state, the workpieces are heated in a furnace to 1100 C. Cooling of the workpiece during bending on a press is allowed to a temperature of at least 800 C.

bottom stamping

I - position of the press before stamping; II - the beginning of the flanging of the bottom; III - end of flanging; IV - the beginning of the removal of the finished bottom from the punch; V - the end of the removal of the finished bottom; 1 - blank; 2 - punch; 3 - stretching ring; 4 - ejector.

The stamping of the bottoms is carried out on hydraulic presses. The stamping process must be completed at a metal temperature of at least 880 C (normalization temperature). To ensure the specified temperature, it is necessary to heat the workpieces to 1050-1100 C. In order to avoid cooling the heated workpiece, its supply to the press, installation in the stamp and deformation should be carried out without the slightest delay.

Excess metal along the height of the cylindrical part of the bottom, resulting from metal drawing during the stamping process, is subject to trimming, leaving a minimum and uniform allowance for machining.

Stamped half-shells and bottoms have a large layer of scale that must be removed, which is achieved by heating these parts gas burner. When heated, the scale falls away from the base metal, since the coefficient of its thermal expansion differs from that of the pure metal. However, part of the tightly adhering scale still does not disappear, and a pneumatic chisel or grinder is used for final cleaning of the parts.

Continuation of the article about the manufacture of drums.

Temple building is not only a wonderful craft in itself, but also a wonderful opportunity to bring some man-made beauty into the world around you in the form of beautiful temples and churches. Moreover, what is most interesting is the fact that regardless of the age of the temple and its appearance it does not cease to bring to a person some wonderful inner state when a person is in this temple or simply contemplates it from afar. Of course, without a doubt - everything is in the hands of our Lord, but still there is a small merit in this of the masters who were able to create this or that beautiful temple in the literal sense of the physical world. Speaking about temples, one can also state the fact that even if there is a single religion, the form of a particular temple may differ depending on the region where this temple is located. It is difficult to say what this is connected with, perhaps with certain preferences of the people of a particular region, or perhaps with something else, but the fact remains that there are still differences. For example, one of the clear distinguishing features of the temples of our country is the presence in their design of simply stunning tents and helmets. Distinctive feature is the presence of a drum, as well as the domes of our temples have certain curves in their forms that are peculiar only to them, although this architectural difference is perhaps imperceptible to the eye ordinary person. We have been manufacturing drums for the temple in Moscow for already long time and we can say with confidence that a beautiful drum really gives a temple or church a better architectural look. Of course, we provide full production of domes in Moscow with delivery and installation. The dome is quite closely related to the drum, and ideally the way that both are made by the same company is acceptable, and this is how we usually do it. All this is even more important if it is made for a temple in Moscow, because in truth our capital should shine in every respect. Making drums for a temple in Moscow in the modern version very often differs from the technology for making drums of the past. In the case of modern drums, it's all about the material. In the past, the drum was a rather heavy architectural element for a temple or church, since it was mainly made from the same material as the temple itself. That is why the presence of the drum gave an additional and not a small load both on the foundation and on the walls of the temple. In the modern version, for the manufacture of drums for the temple in Moscow, such material as glass fiber reinforced concrete is used, which makes it possible to greatly reduce the weight of the drum itself, and, accordingly, its nominal load on the foundation and walls of the temple itself. We have been working with fiberglass concrete for quite a long time and we can say with confidence that its use is fully justified. First of all, SFRC is a fairly durable material, lighter in comparison with concrete or stone, it can be used to manufacture products of almost any shape, size or design, the service life of the material is extremely long, the SFRC product from our company is fully equipped warranty obligations, the production time of such a product is quite short and, finally, fiberglass concrete has a relatively reasonable price. All this is not all the useful qualities of this material, but most likely these are enough. Also, the manufacture of drums for the temple in Moscow and the Moscow region is often associated with various kinds of decoration. Very often, drums have in their design both real windows and so-called false windows, therefore, decor is used to frame such windows, for example, inlaid elements with gold or gold. This is perfectly combined in such cases when church domes are gilded in Moscow and the gilding procedure can be performed synchronously. In addition to making drums for a temple in Moscow, you can order the manufacture of any product from SFB, as well as almost anything you like, if it is related to the temple craft. If we are talking about the construction of a temple in Moscow, then in addition to the domes and drums, one can certainly not do without a beautiful domed cross. Making crosses for the church in Moscow and the Moscow region is also one of the main activities of our company. If you need to manufacture drums for a temple in Moscow, then we can not only manufacture a drum, but also organize its delivery and installation directly on site, and of course, you can contact us on almost any issue related to temples and churches, and consultations from our craftsmen are available to everyone absolutely free of charge and in full. For any questions you are interested in, call us at the indicated numbers or write on the "Contacts" page.

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  Making drums for the temple in Moscow and the Moscow region.
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  View of the drum cover for the temple in Moscow from the inside
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  Installation of the dome on the temple drum in Moscow with a large crane
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  Beautiful view of the drum with windows on the temple in Moscow
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  Manufacturing and installation of a drum for a Moscow church with false windows.
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  Making a drum for a temple in Moscow - with windows and false windows