Why is a centrifuge needed in flour milling? What are centrifuges used for? Safety requirements when working with laboratory centrifuges

There are two main types of centrifuges: settling and filtering. Settling centrifuges are used to separate emulsions and suspensions by sedimenting dispersed particles under the influence of centrifugal forces. Filter centrifuges are also widely used in the chemical industry.

Centrifuge classification In general, it is possible according to the following parameters:

• by type of process organization (continuous and periodic);
• by shaft location (inclined, horizontal, vertical);
• according to the method of sludge unloading (with centrifugal unloading, gravity, auger, manual, etc.)

Based on the separation factor, centrifuges are divided into two groups and are called normal centrifuges (K p<300) и сверхцентрифугами (К р >3000).

Normal centrifuges are used most often to separate all suspensions except those with very low concentrations of solids. Supercentrifuges, in turn, are used to separate fine suspensions and emulsions.

Operating principle of a decanter centrifuge

If we divide centrifuges according to their purpose, we can distinguish settling, filtering and separating centrifuges.

• Filter centrifuges are equipped with perforated drums, covered on the inside, usually with fabric or other filter membrane. This type of centrifuge is used to separate suspensions that have a granular or crystalline solid phase, as well as solid and piece materials.
• Settling centrifuges, which have a solid drum without holes, are used to separate suspensions that are difficult to filter, as well as to clarify suspensions containing a small amount of solid phase.
• Separating centrifuges are also equipped with a solid drum. This type of centrifuge is most often used to separate concentrated suspensions and emulsions.

In addition to the above, centrifuges are divided according to the method of unloading sediment. Unloading of sludge can be done manually, using scrapers and knives that move back and forth, and using gravity or centrifugal force.

Centrifuges can also be divided according to the structure of the supports, which are divided into suspended and standing, and according to the location of the axis - vertical, horizontal and inclined.

Based on the process of organizing centrifugation, devices are divided into continuous and periodic.

Centrifuges operating periodically have three main periods of operation:

1. Starting the centrifuge and filling its drums.
2. Rotation of the drum at a constant speed, as well as separation of a heterogeneous mixture.
3. Drum braking and unloading.

The drum is filled when the unfilled drum rotates at a certain speed, which is less than the operating speed, or when the full rotation speed is reached. In some cases, the drum must be loaded before the centrifuge is started. Removal of sediment occurs after the centrifuge is stopped or when the drum rotates at low speed.

Quite often, after the main centrifugation process has been carried out, it becomes necessary to wash the sediment. To do this, the wash water is squeezed out, which is done by additionally starting the centrifuge drum. In some cases, it is also necessary to wash out certain components of the original mixture.

In centrifuges that operate periodically, a solid drum or one with holes is used.

Operating principle of drum centrifuge

In this case, the drum is enclosed in a casing that serves as a collector of filtrate or washing liquid, as well as a protective fence in case of failure or destruction of the drum. The rotation of the drum is carried out by an electric motor.

Centrifugal force forces the liquid through the filter material and holes in the drum. The liquid is collected in the casing and then removed through a pipeline.

If it is necessary to obtain sludge containing a minimum amount of moisture, then perforated drums are used. With their help, it is possible to achieve a final sludge moisture content of about 1-5% (with a very crushed solid phase - up to 40%). If solid drums are used for these purposes, much more moisture will remain in the sludge (about 70% or more).

In order to increase the separation efficiency, special ring inserts are installed in solid drums, which reduce the speed of movement of the liquid located near the walls. In this way, the settling process of solid particles is significantly improved.

Batch centrifuges are usually produced with a vertical shaft. The material discharge in such centrifuges can be bottom or top. Bottom unloading is considered more convenient, but it requires a lot of physical labor. To facilitate unloading, the devices are often equipped with an easily controlled mechanical shovel. Some centrifuges of this type are self-emptying.

If in standing centrifuges equipped with a vertical shaft and a rigid support, an uneven distribution of the processed material occurs, then unsafe and rather strong vibrations of the drum occur. Because of this, modern centrifuges are equipped with elastic supports, while the shaft bearing is installed in a spherical sleeve.

The most common batch centrifuges are three-column centrifuges and top-mounted centrifuges.

Centrifuge classification:

The operating principle of this centrifuge is that the suspension is fed through a pipe into the inner drum, and then discharged through the windows into the settling drum. At this stage, the suspension is separated. The clarified liquid enters the casing and is discharged through the pipe. The auger moves the sediment and discharges it through the nozzle.

Laboratory centrifuges are designed to separate liquid samples into fractions by applying centrifugal force. The required effect is achieved due to the fact that substances are deposited at different rates, depending on the mass and density of the particles included in their composition. As a result, the heaviest components of the solution accumulate at the bottom of the container, and the light ones - on the surface.

Application area

Centrifuges are a mandatory element of laboratory equipment:

• medical and research centers;
• veterinary clinics;
• chemical, cosmetic and pharmaceutical production;
• blood centers;
• mining and processing enterprises in the oil industry;
• certification and supervisory authorities;
• enterprises Food Industry and etc.

Laboratory centrifuge device

A modern laboratory centrifuge is a complex electromechanical device, the main components of which are:

• metal, corrosion-resistant housing;
• inner chamber;
• rotor;
• electric motor;
• control Panel.

In addition, manufacturers equip equipment with support systems designed to ensure safe operation and improve the quality of sample processing. These include:

• protection against excessive vibration caused by imbalance;
• automatic rotor recognition;
• lid lock that prevents it from opening until the engine stops completely, etc.

Safety requirements when working with laboratory centrifuges

First of all, you need to accurately select the operating parameters:

• type of rotor and adapter;
• acceleration mode and maximum speed;
• duration of centrifugation;
• temperature regime;
• limiting value of centrifugal acceleration, etc.

To solve modern problems in the field of biochemical, genetic analysis, etc., fractionation of biomaterial is carried out at high speeds. The modern laboratory microcentrifuges of the British brand Centurion Scientific used for these purposes are distinguished by exceptional reliability and safety due to being equipped with special technologies to protect against accidental operator errors.

However, even such an intelligent device can fail and become a potential source of serious problems if the conditions and procedures for its operation are not followed. To avoid any complications, the following rules should be followed:

• install the equipment on a solid base in a strictly horizontal position;
• even in a small laboratory, you should not keep several centrifuges and other instruments sensitive to vibration on the same table;
• the atmosphere of the room should not contain any admixtures of flammable gases and aggressive substances;
• The centrifuge body should be grounded to prevent electric shock to personnel;
• the equipment must be positioned in such a way that there is a distance of at least 30 cm from the outlet of the ventilation hole to the nearest obstacle;
• air flows coming out of the centrifuge should not fall directly on people;
• all work on installing and removing sample tubes must be performed with rubber gloves to protect the skin from exposure to chemicals;
• when the load is incomplete, pairs of test tubes should be placed in diametrically opposite rotor cells;
• even when using stoppers, the top level of the sample should be no closer than 1 cm from the edge of the test tube;
• open containers are filled to a maximum of 75% of the maximum permissible volume;
• before turning on the engine, make sure that the rotor is securely fastened to the axis and rotates freely, without jamming or friction;
• the lid of the working chamber closes tightly until it clicks, indicating that the locking device is turned on;
• The compartment with the rotor can only be opened after it has completely stopped.

Forbidden:

• set speeds that exceed the maximum permissible value for a specific type of rotor, test tubes, or test samples;
• perform any manipulations with the lid open and the rotor rotating;
• load samples whose total mass is higher than the limit value set for the centrifuge or rotor;
• place test tubes in diametrically opposite cells of the rotor, the mass of which, taking into account the contents, differs by more than 3.5 g;
• use uncertified, non-standard or homemade test tubes;
• turn on the centrifuge without removing the locking transport nut.

Criterias of choice

When choosing a specific equipment model, the following points should be considered:

• type of laboratory - in specialized institutions, for example medical ones, work is carried out with a certain set of samples: blood, urine, saliva, sweat, etc. In research centers, the range of processed materials is much wider, and accordingly, universal equipment is required, with a wide range of adjustments of operating parameters. Thus, for medical institutions we can recommend Centurion Scientific centrifuges of the PrO-Hospital, PrO-Cyt and PrO-PRP series.

• the total volume of samples processed within one cycle - as part of a series of equipment, manufacturers offer installations of various capacities. If you choose a model that is too large, the rotor will constantly remain underloaded, which entails excessive energy consumption and also increases the risk of uneven distribution of samples, increased vibration and premature failure. Insufficient capacity will lead to increased time spent on research, which also has a negative effect. Thus, in the PrO-Analytical series of centrifuges there are models designed for maximum volumes from 48 to 3000 ml, which allows you to choose the appropriate option for almost any laboratory.

• varieties and types of rotors - it is necessary to take into account what type of tubes will be used in the process of working with samples and the method of research. For industrial and scientific research laboratories, it is better to choose centrifuge models that support the maximum number of rotor types.

Only a properly selected centrifuge will ensure efficient sample processing at an optimal level of time and energy costs.

Centrifuges can be with a vertical and horizontal arrangement of the shaft and drum, periodic action (suspension supply and sediment unloading are carried out periodically), semi-continuous (suspension is supplied continuously, and sediment is unloaded periodically) and continuous action (suspension supply and sediment unloading are carried out continuously).

A batch settling centrifuge with manual sediment discharge (Fig. 7.6) consists of a drum mounted on a rotating shaft and placed in a housing. Under the influence of the centrifugal force that occurs when the drum rotates, solid particles are deposited in the form of a continuous layer of sediment on the drum wall, and the clarified liquid is poured into the casing and removed through the pipe located below. At the end of the process, the sediment is discharged from the centrifuge.

The process in a settling centrifuge consists of separating (sedimenting) the suspension and squeezing or compacting the sediment.

Continuous settling horizontal centrifuges with auger sludge discharge (NOGSH) are used in starch production to obtain concentrated starch sludge and in other industries.

The centrifuge consists of a rotor and an internal screw device enclosed in a housing. The suspension is fed through a central pipe into the hollow auger shaft. At the exit from this pipe inside the screw, the suspension under the influence of centrifugal force is distributed in the rotor cavity.

The rotor rotates in a casing in hollow journals. The auger rotates in journals located inside the rotor journals. Under the influence of centrifugal force, solid particles are thrown towards the walls of the rotor, and the liquid forms an inner ring, the thickness of which is determined by the position of the drain holes at the end of the rotor. The resulting sediment moves due to the lag of the screw rotation speed from the rotor rotation speed to the holes in the rotor, through which it is discharged into the chamber 6 and removed from the centrifuge.

As it moves along the rotor, the sediment becomes compacted. If necessary, it can be washed.

Filter centrifuges periodic and continuous operation are divided according to the shaft location into vertical and horizontal, according to the method of sludge unloading - into centrifuges with manual, gravitational, pulsating and centrifugal sludge unloading. The main difference between filter centrifuges and settling centrifuges is that they have a perforated drum covered with filter fabric.

In a batch filter centrifuge (Fig. 8.14), the suspension is loaded into the drum from above. After loading the suspension, the drum is rotated. The suspension is thrown towards the inner wall of the drum under the action of centrifugal force. The liquid dispersion phase passes through the filter partition, and the precipitate falls on it. The filtrate is directed through the drain pipe into the collection tank. The sediment after the end of the filtration cycle is discharged manually through the lid 3.

The design of a filter centrifuge with a perforated drum is similar to the design of an automatic settling centrifuge with continuous knife removal of sediment.

Based on the separation factor, centrifuges can be divided into two groups: normal centrifuges(K r< 3500) и supercentrifuges(K p > 3500).

Normal centrifuges are used mainly for separating various suspensions, with the exception of suspensions with a very low solids concentration, and also for removing moisture from piece materials. Supercentrifuges are used to separate emulsions and fine suspensions.

Normal centrifuges can be settling and filtering. Supercentrifuges are settling-type devices and are divided into tubular supercentrifuges, used to separate fine suspensions, and liquid separators, used to separate emulsions.

An essential feature of the type of centrifuge is the method of unloading sediment from it. Unloading is done manually, using knives or scrapers, screws and pistons moving back and forth (pulsating), as well as under the influence of gravity and centrifugal force.

Based on the location of the rotation axis, vertical, inclined and horizontal centrifuges are distinguished. The rotor shaft of a vertical centrifuge is supported at the bottom or suspended from the top.

Depending on the organization of the process, centrifuges are divided into periodic and continuous ones.

Three-column centrifuges. Devices of this type belong to normal settling or filtering centrifuges of periodic operation with manual discharge of sediment.

In a three-column filter centrifuge with top discharge of sediment (Fig. V-14), the suspension to be separated is loaded into a perforated rotor 1, the inner surface of which is covered with a filter cloth or metal mesh. The rotor, using a cone 2, is mounted on a shaft 3, which is driven by an electric motor through a V-belt drive. The liquid phase of the suspension passes through the fabric (or mesh) and holes in the rotor wall and is collected in the bottom of the frame 4, covered with a stationary casing 5, from where it is removed for further processing. The sediment formed on the walls of the rotor is removed, for example, using a spatula, after opening the casing cover 6.

To mitigate the impact of vibrations on the foundation, the frame 7 with the rotor, drive and casing mounted on it is suspended using vertical rods 8 with ball heads on three columns 9 located at an angle of 120°. This provides some freedom when the rotor vibrates. The centrifuge is equipped with a brake, which can only be activated after the electric motor has stopped.

Three-column centrifuges are also made with bottom discharge of sediment, which is more convenient in production conditions.

The centrifuges under consideration are characterized by their small height and good stability and have become widespread for long-term centrifugation.

Hanging centrifuges. These centrifuges are also classified as normal settling or batch filter centrifuges with a vertical rotor and a manual sediment discharge device.

In Fig. V-15 shows an overhead settling centrifuge with bottom discharge of sludge. The initial suspension is fed through pipeline 1 into a rotor 2 with solid walls, mounted on the lower end of the shaft 3. The upper end of the shaft has a conical or ball bearing (often equipped with a rubber gasket) and is driven by an electric motor directly connected to it. The solid phase of the suspension, since its density is greater than the density of the liquid phase, is thrown under the action of centrifugal force to the rotor machines and is deposited on them. The liquid phase is located in the form of an annular layer closer to the rotor axis and, as the newly arriving portions of the suspension are separated, it pours over the upper edge of the rotor into the space between it and the stationary casing 4. The liquid is removed from the centrifuge through fitting 5. To unload the sediment, the conical cover 6 is lifted on a chain and push it manually between the ribs 7, which serve to connect the rotor to the shaft.

Overhead settling centrifuges are designed to separate fine suspensions of low concentration, which allows the suspension to be fed into a rotating rotor continuously until a layer of sediment of sufficient thickness is obtained.

Hanging filter centrifuges make it easier to remove sediment from the rotor and are therefore used for short centrifugation processes.

Modern suspended centrifuges are fully automated and program-controlled. The advantage of these centrifuges is that some rotor vibration is acceptable. In addition, they prevent aggressive liquids from coming into contact with the support and drive. Currently, overhead centrifuges with manual sludge unloading are gradually being replaced by centrifuges of more advanced designs.

In suspended self-unloading In centrifuges, the lower part of the rotor has a conical shape, and the angle of inclination of its walls is greater than the angle of repose of the resulting sediment. With this rotor design, the sediment slides off its walls when the centrifuge stops.

To prevent vibrations resulting from uneven loading of the rotor in suspended centrifuges, a ring valve is used, through which the incoming suspension is distributed evenly along the entire perimeter of the rotor. To facilitate the unloading of sediment from suspended centrifuges, scrapers are sometimes used to cut sediment from the walls of the rotor at a reduced rotation speed.

Horizontal centrifuges with a knife device for sediment removal. Centrifuges of this design are normal settling or batch filter centrifuges with automated control.

In a horizontal filter centrifuge with a knife device (Fig. V-16), the operations of loading the suspension, centrifugation, washing, mechanical drying of the sediment and its unloading are performed automatically. The centrifuge is controlled by an electro-hydraulic automatic device, which allows the degree of filling of the rotor to be controlled by the thickness of the sediment layer.

The suspension enters the perforated rotor 1 through pipe 2 and is evenly distributed in it. On the inner surface of the rotor there are lining sieves, filter fabric and a grid, which ensures a tight fit of the sieves to the rotor to prevent them from bulging, which is unacceptable when removing sediment with a knife. The rotor is located in a cast casing 3, consisting of a lower stationary part and a removable cover. The centrifuge is removed from the centrifuge through fitting 4. The sediment is cut off by knife 5 (which, when the rotor rotates, is lifted by hydraulic cylinder 6), falls into a guide inclined chute 7 and is removed from the centrifuge through channel 8. The described centrifuge is intended for separating medium and coarse suspensions.

C centrifuges with a pulsating piston for unloading sediment. These devices belong to continuous filter centrifuges with a horizontal rotor (Fig. V-17). The suspension through pipe 1 enters the narrow part of the conical funnel 2, rotating at the same speed as the perforated rotor 3, covered from the inside with a metal slotted sieve 4. Suspension moves along the inner surface of the funnel and gradually acquires a speed almost equal to the speed of rotation of the rotor. Then the suspension is thrown through the holes in the funnel onto the inner surface of the sieve in the area in front of piston 5. Under the influence of centrifugal force, the liquid phase passes through the slots of the sieve and is removed from the centrifuge casing through fitting 6. The solid phase is retained on the sieve in the form of sediment, which periodically moves to edge of the rotor as the piston moves to the right approximately 1/10 of the rotor length. Thus, for each stroke of the piston, an amount of sediment corresponding to the length of the piston stroke is removed from the rotor; in this case the piston makes 10-16 strokes in 1 min. The sediment is removed from the casing through channel 7.

The piston is mounted on a rod 8 located inside a hollow shaft 9, which is connected to an electric motor and imparts rotational motion to the rotor. The hollow shaft with the rotor and the rod with the piston and conical funnel rotate at the same speed. The direction of the reciprocating movement of the piston changes automatically. At the other end of the rod, a disk 10 is mounted perpendicular to its axis, on the opposite surfaces of which, in a special device, the oil pressure created by the gear pump is alternately applied.

In centrifuges with a device for washing sediment, the casing is divided into two sections, through one of which the washing liquid is discharged.

The described centrifuge is used for processing coarse, easily separated suspensions, especially in cases where damage to sediment particles during unloading is undesirable.

Centrifuges with inertial sediment discharge. These centrifuges are normal continuous filter centrifuges with a vertical conical rotor.

WITH suspension containing coarse material, such as coal, ore, sand, enters the centrifuge from above through funnel 1 (Fig. V-19). Under the action of centrifugal force, the suspension is thrown towards a conical rotor 2 with perforated walls. In this case, the liquid phase of the suspension passes through the holes of the rotor and is removed from the centrifuge through channel 3, and solid particles, the size of which should be larger than the size of the holes, are retained inside the rotor. The layer of solid particles thus formed, the friction angle of which is less than the angle of inclination of the rotor walls, moves to its lower edge and is removed from the centrifuge through channel 4. In order to increase the duration of the period during which the liquid is separated from the solid particles, their movement is slowed down by the screw 5, rotating slower than the rotor. The required difference in the speed of rotation of the rotor and auger is achieved using a gear reducer.

Centrifuges with inertial sediment discharge are used to separate suspensions and coarse-grained materials.

Centrifuges with vibrational sediment discharge. Centrifuges of this design are normal continuous filter centrifuges with a vertical or horizontal conical rotor.

The disadvantage of the centrifuge described above with inertial sediment discharge is the inability to control the speed of sediment movement along the walls of the rotor. This drawback is eliminated in centrifuges with vibrational sediment discharge, the operating principle of which is as follows.

The centrifuge has a conical rotor with a wall inclination angle less than the angle of friction of the sediment against the wall. Therefore, the movement of sediment along the walls from the narrow to the wide end of the rotor under the influence of centrifugal force is impossible. In this case, axial vibrations, which are created by a mechanical, hydraulic or electromagnetic device, are used to move the sediment in the rotor. In this case, the intensity of vibration determines the speed of sludge movement in the rotor, which allows, in particular, to ensure the required degree of sludge dewatering.

Liquid separators. These devices are continuous settling supercentrifuges with a vertical rotor.

Such supercentrifuges include liquid separators with a rotor with a diameter of 150-300 mm, rotating at a speed of 5000-10000 rpm. They are intended for separating emulsions, as well as for clarifying liquids.

In a disc-type liquid separator (Fig. V-20), the mixture being processed in the settling zone is divided into several layers, as is done in settling tanks to reduce the path traversed by the particle during settling. The emulsion is fed through the central pipe 1 to the lower part of the rotor, from where, through holes in the plates 2, it is distributed in thin layers between them. The heavier liquid, moving along the surface of the plates, is thrown by centrifugal force to the periphery of the rotor and removed through hole 3. The lighter liquid moves to the center of the rotor and is removed through the annular channel 4.

The holes in the plates are located approximately along the interface between the heavier and lighter liquids. In order for the liquid to keep up with the rotating rotor, it is equipped with ribs 5. For the same purpose, the plates have protrusions that simultaneously fix the distance between them.

An example of disc-type separators is the widespread milk separators.

This nondescript gray cylinder is the key link in the Russian nuclear industry.

It doesn’t look very presentable, of course, but it’s worth understanding its purpose and taking a look at specifications, as you begin to realize why the secret of its creation and structure is protected by the state like the apple of its eye.

Yes, I forgot to introduce: here is a gas centrifuge for separating uranium isotopes VT-3F (nth generation). The principle of operation is elementary, like a milk separator; the heavy is separated from the light by the influence of centrifugal force. So what is the significance and uniqueness? First, let's answer another question - in general, why separate uranium? Natural uranium, which lies right in the ground, is a cocktail of two isotopes: uranium-238 and uranium-235 (and 0.0054% U-234). Uranium-238 is just heavy, gray metal. You can use it to make an artillery shell, or... a keychain. But what can be made from uranium-235? Well, firstly, an atomic bomb, and secondly, fuel for nuclear power plants. And here we come to the key question - how to separate these two, almost identical atoms, from each other? No, really, HOW?! By the way: The radius of the nucleus of a uranium atom is -1.5 10-8 cm. In order for uranium atoms to be driven into the technological chain, it (uranium) must be turned into a gaseous state. There is no point in boiling; it is enough to combine uranium with fluorine and obtain HFC uranium hexafluoride. The technology for its production is not very complicated and expensive, and therefore HFCs are obtained directly from where this uranium is mined. UF6 is the only highly volatile uranium compound (when heated to 53°C, the hexafluoride (pictured) directly transforms from a solid to a gaseous state). Then it is pumped into special containers and sent for enrichment.

A little history At the very beginning of the nuclear race, the greatest scientific minds of both the USSR and the USA mastered the idea of ​​diffusion separation - passing uranium through a sieve. The small 235th isotope will slip through, and the “fat” 238th isotope will get stuck. Moreover, making a sieve with nano-holes for Soviet industry in 1946 was not the most difficult task. From the report of Isaac Konstantinovich Kikoin at the scientific and technical council under the Council of People's Commissars (given in the collection of declassified materials on the USSR atomic project (Ed. Ryabev)): Currently, we have learned to make meshes with holes of about 5/1,000 mm, i.e. . 50 times greater than the free path of molecules at atmospheric pressure. Consequently, the gas pressure at which the separation of isotopes on such grids will occur must be less than 1/50 of atmospheric pressure. In practice, we assume to work at a pressure of about 0.01 atmospheres, i.e. under good vacuum conditions. Calculations show that to obtain a product enriched to a concentration of 90% with a light isotope (this concentration is sufficient to obtain explosive), you need to connect about 2,000 such stages in a cascade. In the machine we are designing and partially manufacturing, it is expected to produce 75-100 g of uranium-235 per day. The installation will consist of approximately 80-100 “columns”, each of which will have 20-25 stages installed.” Below is a document - Beria's report to Stalin on the preparation of the first atomic bomb explosion. Below is a short information about the nuclear materials produced by the beginning of the summer of 1949.

And now imagine for yourself - 2000 hefty installations, for the sake of just 100 grams! Well, what to do with it, we need bombs. And they began to build factories, and not just factories, but entire cities. And okay, only the cities, these diffusion plants required so much electricity that they had to build separate power plants nearby. In the photo: the world's first gas diffusion uranium enrichment plant K-25 in Oak Ridge (USA). Construction cost $500 million. The length of the U-shaped building is about half a mile.

In the USSR, the first stage D-1 of plant No. 813 was designed for a total output of 140 grams of 92-93% uranium-235 per day at 2 cascades of 3100 separation stages identical in power. An unfinished building was allocated for production aircraft factory in the village of Verkh-Neyvinsk, which is 60 km from Sverdlovsk. Later it turned into Sverdlovsk-44, and plant 813 (pictured) into the Ural Electrochemical Plant - the world's largest separation plant.

And although the technology of diffusion separation, albeit with great technological difficulties, was debugged, the idea of ​​​​developing a more economical centrifuge process did not leave the agenda. After all, if we manage to create a centrifuge, then energy consumption will be reduced from 20 to 50 times! How does a centrifuge work? Its structure is more than elementary and similar to the old one washing machine operating in the “spin/dry” mode. The rotating rotor is located in a sealed casing. Gas (UF6) is supplied to this rotor. Due to the centrifugal force, hundreds of thousands of times greater than the Earth’s gravitational field, the gas begins to separate into “heavy” and “light” fractions. Light and heavy molecules begin to group in different zones of the rotor, but not in the center and along the perimeter, but at the top and bottom. This occurs due to convection currents - the rotor cover is heated and a counterflow of gas occurs. There are two small intake tubes installed at the top and bottom of the cylinder. A lean mixture enters the lower tube, and a mixture with a higher concentration of 235U atoms enters the upper tube. This mixture goes into the next centrifuge, and so on, until the concentration of uranium 235 reaches the desired value. A chain of centrifuges is called a cascade.

Technical features. Well, firstly, the rotation speed - in the modern generation of centrifuges it reaches 2000 rpm (I don’t even know what to compare it with... 10 times faster than a turbine in an aircraft engine)! And it has been working non-stop for THREE DECADES! Those. Now centrifuges, turned on under Brezhnev, are rotating in cascades! The USSR no longer exists, but they keep spinning and spinning. It is not difficult to calculate that during its working cycle the rotor makes 2,000,000,000,000 (two trillion) revolutions. And what bearing will withstand this? Yes, none! There are no bearings there. The rotor itself is an ordinary top; at the bottom it has a strong needle resting on a corundum bearing, and the upper end hangs in a vacuum, held by an electromagnetic field. The needle is also not simple, made from ordinary wire for piano strings, it is very hardened in a cunning way(which is GT). It is not difficult to imagine that with such a frantic rotation speed, the centrifuge itself must be not just durable, but extremely durable. Academician Joseph Fridlyander recalls: “They could have shot us three times. Once, when we had already received the Lenin Prize, there was a major accident, the lid of the centrifuge flew off. The pieces scattered and destroyed other centrifuges. A radioactive cloud rose. We had to stop the entire line - a kilometer of installations! At Sredmash, General Zverev commanded the centrifuges; before the atomic project, he worked in Beria’s department. The general at the meeting said: “The situation is critical. The country’s defense is under threat. If we don’t quickly rectify the situation, the year 1937 will repeat for you.” And immediately closed the meeting. Then we completely came up with new technology with a completely isotropic uniform cover structure, but very complex installations were required. Since then, these types of lids have been produced. There were no more troubles. In Russia there are 3 enrichment plants, many hundreds of thousands of centrifuges.”
In the photo: tests of the first generation of centrifuges

The rotor housings were also initially made of metal, until they were replaced by... carbon fiber. Lightweight and highly tensile, it is an ideal material for a rotating cylinder. Alexander Kurkin, General Director of UEIP (2009-2012), recalls: “It got to the point of ridiculousness. When they were testing and checking a new, more “resourceful” generation of centrifuges, one of the employees did not wait for the rotor to stop completely, disconnected it from the cascade and decided to carry it by hand to the stand. But instead of moving forward, no matter how he resisted, he embraced this cylinder and began to move backward. So we saw with our own eyes that the earth rotates, and the gyroscope is a great force.” Who invented it? Oh, it's a mystery, wrapped in mystery and shrouded in suspense.

Here you will find captured German physicists, the CIA, SMERSH officers and even the downed spy pilot Powers. In general, the principle of a gas centrifuge was described at the end of the 19th century. Still at dawn Atomic project engineer of the Special Design Bureau Kirov plant Viktor Sergeev proposed a centrifugal separation method, but at first his colleagues did not approve of his idea. In parallel, scientists from defeated Germany struggled to create a separation centrifuge at a special research institute-5 in Sukhumi: Dr. Max Steenbeck, who worked as a leading Siemens engineer under Hitler, and former Luftwaffe mechanic, graduate of the University of Vienna, Gernot Zippe. In total, the group included about 300 “exported” physicists. Remembers CEO ZAO Centrotech-SPb State Corporation Rosatom Alexey Kaliteevsky: “Our experts came to the conclusion that the German centrifuge is absolutely unsuitable for industrial production.

Steenbeck's apparatus did not have a system for transferring the partially enriched product to the next stage. It was proposed to cool the ends of the lid and freeze the gas, and then defrost it, collect it and put it into the next centrifuge. That is, the scheme is inoperative. However, the project had several very interesting and unusual technical solutions. These “interesting and unusual solutions” were combined with the results obtained by Soviet scientists, in particular with the proposals of Viktor Sergeev. Relatively speaking, our compact centrifuge is one-third the fruit of German thought, and two-thirds Soviet.” By the way, when Sergeev came to Abkhazia and expressed his thoughts about the selection of uranium to the same Steenbeck and Zippe, Steenbeck and Zippe dismissed them as unrealizable. So what did Sergeev come up with? And Sergeev’s proposal was to create gas selectors in the form of pitot tubes.

But Dr. Steenbeck, who, as he believed, had eaten his teeth on this topic, was categorical: “They will slow down the flow, cause turbulence, and there will be no separation!” Years later, while working on his memoirs, he would regret it: “An idea worthy of coming from us! But it never occurred to me...” Later, once outside the USSR, Steenbeck no longer worked with centrifuges. But before leaving for Germany, Geront Zippe had the opportunity to get acquainted with a prototype of Sergeev’s centrifuge and the ingeniously simple principle of its operation. Once in the West, “the cunning Zippe,” as he was often called, patented the centrifuge design under his own name (patent No. 1071597 of 1957, declared in 13 countries). In 1957, having moved to the USA, Zippe built a working installation there, reproducing Sergeev’s prototype from memory. And he called it, let’s pay tribute, “Russian centrifuge” (pictured).

By the way, Russian engineering has shown itself in many other cases. An example is a simple emergency shut-off valve. There are no sensors, detectors or electronic circuits. There is only a samovar faucet, which touches the cascade frame with its petal. If something goes wrong and the centrifuge changes its position in space, it simply turns and closes the inlet line. It's like the joke about an American pen and a Russian pencil in space.

Our days This week the author of these lines was present at a significant event - the closure of the Russian office of observers of the US Department of Energy under the HEU-LEU contract. This deal (highly enriched uranium - low enriched uranium) was, and remains, the largest agreement in the field of nuclear energy between Russia and America. Under the terms of the contract, Russian nuclear scientists processed 500 tons of our weapons-grade (90%) uranium into fuel (4%) HFCs for American nuclear power plants. Revenues for 1993-2009 amounted to 8.8 billion US dollars. This was the logical outcome of the technological breakthrough of our nuclear scientists in the field of isotope separation made in the post-war years. In the photo: cascades of gas centrifuges in one of the UEIP workshops. There are about 100,000 of them here.

Thanks to centrifuges, we have obtained thousands of tons of relatively cheap, both military and commercial product. The nuclear industry is one of the few remaining (military aviation, space) where Russia holds undisputed primacy. Foreign orders alone for ten years in advance (from 2013 to 2022), Rosatom’s portfolio, excluding the HEU-LEU contract, amounts to $69.3 billion. In 2011, it exceeded 50 billion... The photo shows a warehouse of containers with HFCs at the UEIP.

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