Why do you need a centrifuge in the laboratory. The centrifuge is laboratory medical. Centrifuges in the aerospace industry

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

Of course, it doesn’t look very presentable, but it’s worth understanding its purpose and looking at specifications, as you begin to realize why the state guards the secret of its creation and structure like the apple of its eye.

Yes, I forgot to introduce: in front of you is a gas centrifuge for separating uranium isotopes VT-3F (n-th generation). The principle of operation is elementary, like that of a milk separator, heavy, under the influence of centrifugal force, is separated from the light. So what is the significance and uniqueness? To begin with, let's answer another question - but 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 a heavy, gray metal. You can make an artillery shell out of it, well, or ... a keychain.

But what can be done 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 the 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 get HFC uranium hexafluoride.

The technology for its production is not very complicated and expensive, and therefore HFCs are obtained right where this uranium is mined. UF6 is the only highly volatile compound of uranium (when heated to 53 ° C, hexafluoride (pictured) directly passes from a solid to a gaseous state). Then it is pumped into special containers and sent for enrichment.

A bit of history At the very beginning of the nuclear race, the greatest scientific minds, both the USSR and the USA, mastered the idea of diffusion separation - passing uranium through a sieve. The small 235th isotope will slip through, while the "fat" 238th one will get stuck. And to make a sieve with nano-holes for the 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)): At present, we have learned how to make grids with holes of about 5/1,000 mm, i.e. . 50 times the mean free path of molecules at atmospheric pressure. Therefore, the gas pressure at which isotope separation on such grids will occur must be less than 1/50 of atmospheric pressure. In practice, we expect to work at a pressure of about 0.01 atmospheres, i.e. under good vacuum conditions. The calculation shows that to obtain a product enriched to a concentration of 90% in a light isotope (such a concentration is sufficient to obtain explosive), you need to connect in a cascade about 2,000 of these steps.

In the machine designed and partially manufactured by us, 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 contain 20-25 steps." Below is a document - Beria's report to Stalin on the preparation of the first nuclear explosion. Below is a small reference to the accumulated nuclear materials by the beginning of the summer of 1949.

And now imagine for yourself - 2000 hefty installations, for the sake of some 100 grams! Well, where to go, bombs are needed. And they began to build factories, and not just factories, but entire cities. And okay, only cities, these diffusion plants required so much electricity that they had to build separate power plants nearby. In the photo: the world's first K-25 uranium gaseous diffusion enrichment plant 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 in 2 cascades of 3100 separation stages identical in power. An unfinished aircraft plant in the village of Verkh-Neyvinsk, which is 60 km from Sverdlovsk, was allocated for production. Later it turned into Sverdlovsk-44, and the 813th plant (pictured) into the Ural Electrochemical Plant - the world's largest separating production.

And although the technology of diffusion separation, albeit with great technological difficulties, was debugged, the idea of mastering a more economical centrifugal process did not leave the agenda. After all, if you manage to create a centrifuge, then energy consumption will be reduced from 20 to 50 times! How is a centrifuge set up? It is arranged more than elementarily and looks like the old one. washing machine operating in the "spin / dry" mode. In a sealed casing is a rotating rotor. This rotor is supplied with gas (UF6).

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 backflow of gas occurs. At the top and bottom of the cylinder there are two small tubes - the intake.

A depleted mixture enters the lower tube, and a mixture with a higher concentration of 235U atoms enters the upper tube. This mixture enters the next centrifuge, and so on, until the concentration of uranium 235 reaches the required 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 with ... 10 times faster than a turbine in an aircraft engine)! And it has been working non-stop for THREE DECADES of years! Those. now the centrifuges that were turned on under Brezhnev are spinning 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 kind of bearing can handle it?

Yes, none! There are no bearings. The rotor itself is an ordinary top, at the bottom it has a strong needle resting on a corundum thrust bearing, and the upper end hangs in a vacuum, held by an electromagnetic field. The needle is also not simple, made of ordinary wire for piano strings, it is hardened in a very tricky way (what - GT). It is not difficult to imagine that with such a frantic rotation speed, the centrifuge itself must be not just durable, but super-strong.

Academician Iosif Fridlyander recalls: “Three times they could have been shot. Once, when we had already received the Lenin Prize, there was a major accident, the lid of the centrifuge flew off. Pieces scattered, destroyed other centrifuges. A radioactive cloud has risen. I had to stop the entire line - a kilometer of installations! In Sredmash centrifuges were commanded by General Zverev, before the atomic project he worked in the department of Beria.

General at the meeting said:“The situation is critical. The defense of the country is under threat. If we do not rectify the situation quickly, the 37th year will repeat for you. And immediately the meeting was closed. We then came up with completely new technology with a completely isotropic uniform lid structure, but very complex setups were required. Since then, these covers have been produced. There were no more troubles. There are 3 enrichment plants in Russia, many hundreds of thousands of centrifuges.

In the photo: tests of the first generation of centrifuges

The rotor cases were also metal at first, until they were replaced by ... carbon fiber. Lightweight and extremely tear resistant, it is an ideal material for a rotating cylinder.

UEIP General Director (2009-2012) Alexander Kurkin recalls:“It got ridiculous. When testing and testing a new, more "revolving" generation of centrifuges, one of the employees did not wait for the rotor to stop completely, disconnected it from the cascade and decided to transfer it to the stand in his arms. But instead of moving forward, no matter how hard 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?

Oh, it's a mystery steeped in mystery and shrouded in obscurity. Here you have German captured 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. Even at the dawn of the Atomic Project, Victor Sergeev, engineer of the Special Design Bureau of the Kirov Plant, proposed a centrifugal separation method, but at first his colleagues did not approve of his idea. At the same time, scientists from defeated Germany fought over the creation of a separation centrifuge in a special NII-5 in Sukhumi: Dr. Max Steenbeck, who worked under Hitler as the chief engineer of Siemens, and former mechanic"Luftwaffe", a graduate of the University of Vienna Gernot Zippe. In total, the group included about 300 "exported" physicists.

Recalls CEO CJSC "Centrotech-SPb" State Corporation "Rosatom" Alexey Kaliteevsky:“Our specialists came to the conclusion that the German centrifuge is absolutely unsuitable for industrial production. The Steenbeck 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 unfreeze it, collect it and put it into the next centrifuge. That is, the scheme is not working. However, the project had some 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 of Soviet thought.” By the way, when Sergeev came to Abkhazia and expressed to the same Steenbeck and Zippe his thoughts on the selection of uranium, Steenbeck and Zippe dismissed them as unrealizable. So what did Sergeyev come up with.

And Sergeyev's proposal was to create gas sampling devices in the form of Pitot tubes. But Dr. Steenbeck, who, as he believed, ate his teeth on this topic, was categorical: “They will slow down the flow, cause turbulence, and there will be no separation!”

Years later, working on his memoirs, he will regret it:“An idea worthy of coming from us! But it didn’t cross my mind…” Later, when he was outside the USSR, Steenbeck no longer dealt with centrifuges. But Geront Zippe, before leaving for Germany, had the opportunity to get acquainted with the prototype of Sergeyev's centrifuge and the ingeniously simple principle of its operation. Once in the West, "cunning Zippe", as he was often called, patented the design of the centrifuge under his own name (patent No. 1071597 of 1957, pending 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 the elementary emergency shut-off valve. There are no sensors, detectors and electronic circuits. There is only a samovar faucet, which with its petal touches the frame of the cascade. If something goes wrong, and the centrifuge changes its position in space, it simply turns and closes the inlet line. It's like in a joke about an American pen and a Russian pencil in space.

Our Days This week the author of these lines attended a significant event - the closure of the Russian office of observers of the US Department of Energy under the HEU-LEU contract. This deal (high-enriched uranium-low-enriched uranium) was, and still is, the largest nuclear energy agreement 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 postwar 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 received 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 unquestioned superiority. With foreign orders alone for ten years ahead (from 2013 to 2022), Rosatom's portfolio, excluding the HEU-LEU contract, is $69.3 billion. In 2011, it exceeded 50 billion... In the photo, a warehouse of containers with HFCs at UEIP.

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

Normal centrifuges are mainly used for separating various suspensions, except for suspensions with a very low solids concentration, as well as for removing moisture from bulk materials. Super centrifuges are used to separate emulsions and fine suspensions.

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

An essential feature of the type of centrifuges is the method of unloading sediment from them. Unloading is done manually, with the help of knives or scrapers, screws and pistons moving back and forth (pulsating), as well as under the action of gravity and centrifugal force.

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

Depending on the organization of the process, centrifuges are divided into periodically and continuously operating.

Three-column centrifuges. Apparatuses of this type belong to normal settling or filtering centrifuges of periodic action with manual sludge unloading.

In a three-column filter centrifuge with a 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, by means of a cone 2, is mounted on a shaft 3, which is driven by an electric motor through a V-belt transmission. The liquid phase of the suspension passes through the fabric (or mesh) and holes in the wall of the rotor and is collected in the bottom of the bed 4, covered with a fixed casing 5, from where it is discharged for further processing. The sediment formed on the walls of the rotor is removed, for example, with a spatula, after opening the cover of the casing 6.

To mitigate the impact of vibrations on the foundation, the frame 7 with the rotor mounted on it, the drive and the casing are suspended by means of vertical rods 8 with ball heads on three columns 9 located at an angle of 120 °. This provides some freedom for the vibration of the rotor. The centrifuge is equipped with a brake that can only be activated after the 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 low height and good stability and are widely used for long-term centrifugation.

Overhead centrifuges. These centrifuges are also normal settling or filtering centrifuges with a vertical rotor and a manual discharge of the sediment.

On fig. V-15 shows a bottom discharge suspended sludge centrifuge. The feed slurry is fed through conduit 1 to a solid-walled rotor 2 mounted on the lower end of shaft 3. The upper end of the shaft has a conical or ball bearing (often fitted with a rubber gasket) and is driven directly by an electric motor 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 machines of the rotor and is deposited on them. The liquid phase is located in the form of an annular layer closer to the axis of the rotor and, as the newly arriving portions of the suspension are separated, it overflows over the upper edge of the rotor into the space between it and the fixed casing 4. The liquid is removed from the centrifuge through the fitting 5. To unload the sediment, the conical cover 6 is lifted onto the chains and push it manually between the ribs 7, which serve to connect the rotor to the shaft.

Suspended 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 sediment layer of sufficient thickness is obtained.

In hanging filter centrifuges, the removal of sediment from the rotor is facilitated and therefore they are used for short centrifugation processes.

Modern overhead centrifuges are fully automated and have software control. The advantage of these centrifuges is the admissibility of some vibration of the rotor. In addition, they prevent aggressive liquids from entering the support and drive. At present, overhead centrifuges with manual sludge discharge are gradually being replaced by more advanced centrifuges.

In hanging self-unloading 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 arrangement of the rotor, the sediment slides off its walls when the centrifuge stops.

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

Horizontal centrifuges with blades for sediment removal. Centrifuges of this design are normal settling or filtering batch centrifuges with automated control.

In the horizontal blade centrifuge (fig. V-16), the operations of suspension loading, centrifugation, washing, mechanical drying of the precipitate and its discharge are performed automatically. The centrifuge is controlled by an electro-hydraulic automatic machine, which allows controlling the degree of filling of the rotor by the thickness of the sludge layer.

The suspension enters the perforated rotor 1 through the pipe 2 and is evenly distributed in it. On the inner surface of the rotor there are lining sieves, a filter cloth and a grid, which ensures a tight fit of the sieves to the rotor in order to avoid their bulging, which is unacceptable when removing sediment with a knife. The rotor is in a cast casing 3, consisting of a lower stationary part and a removable cover. Centrifuge is removed from the centrifuge through nozzle 4. Sediment is cut off by knife 5 (which, when the rotor rotates, rises with the help of hydraulic cylinder 6), falls into the guide inclined chute 7 and is removed from the centrifuge through channel 8. The described centrifuge is designed to separate medium and coarse suspensions.

C pulsating piston centrifuges for sludge discharge. These devices are continuous filtering centrifuges with a horizontal rotor (Fig. V-17). 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 zone in front of the piston 5. Under the action of centrifugal force, the liquid phase passes through the sieve slots and is removed from the centrifuge casing through the fitting 6. The solid phase is retained on the sieve in the form of sediment, which periodically moves to edge of the rotor when the piston moves to the right by about 1/10 of the length of the rotor. Thus, for each stroke of the piston, the amount of sediment corresponding to the length of the piston stroke is removed from the rotor; while the piston makes 10-16 strokes in 1 min. The precipitate is removed from the casing through channel 7.

The piston is mounted on a rod 8 located inside the hollow shaft 9, which is connected to the electric motor and imparts rotational motion to the rotor. A hollow shaft with a rotor and a rod with a piston and a 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 alternately acts.

In centrifuges with a sediment washer, 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 separable suspensions, especially in cases where it is undesirable to damage the particles of the sludge during its unloading.

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

FROM suspension containing coarse-grained 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 to the 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, while 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 formed in this way, the friction angle of which is less than the angle of inclination of the walls of the rotor, 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 inhibited by the screw 5, rotating slower than the rotor. The necessary difference between the speeds of rotation of the rotor and the screw is achieved using a gear reducer.

Centrifuges with inertial sludge discharge are used to separate suspensions, coarse-grained materials.

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

The disadvantage of the above-described centrifuge with inertial sludge discharge is the inability to control the speed of sludge along the walls of the rotor. This drawback is eliminated in centrifuges with vibratory sludge discharge, the principle of operation of which is as follows.

The centrifuge has a conical rotor with a wall inclination angle smaller than the sediment friction angle along the wall. Therefore, the movement of sediment along the walls from the narrow to the wide end of the rotor under the action of centrifugal force is impossible. In this case, axial vibrations are used to move the sediment in the rotor, which are created by a mechanical, hydraulic or electromagnetic device. In this case, the vibration intensity determines the speed of sludge movement in the rotor, which makes it possible, in particular, to provide the necessary degree of sludge dehydration.

Liquid separators. These units are continuous supercentrifuges with a vertical rotor.

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

In the tray-type liquid separator (Fig. V-20), the mixture to be processed in the settling zone is divided into several layers, as is done in settling tanks to reduce the path traveled by the particle during settling. The emulsion is fed through the central pipe 1 to the lower part of the rotor, from where it is distributed through the holes in the plates 2 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 discharged through the hole 3. The lighter liquid moves to the center of the rotor and is removed through the annular channel 4.

The holes in the trays are located approximately along the interface between the heavier and lighter liquids. In order for the liquid not to lag behind 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 plate-type separators are widely used milk separators.

For the fruitful work of a modern laboratory, it is necessary to have a laboratory centrifuge. Such a medical instrument separates substances of different consistency and density, thanks to it, substances with a maximum specific gravity are placed on the periphery, and with a minimum specific gravity they move closer to the axis of rotation.

Very often in laboratory studies it is necessary to separate a mixture or liquid into homogeneous particles, which, as a rule, have different densities. Around the central axis, a container with liquid in a laboratory centrifuge begins to rotate at great speed. Its constituent particles, which differ in density, are separated from each other, as they are subject to the action of different centrifugal forces.

In scientific laboratories, both specialized centrifuges that perform narrow tasks and universal ones are used.

These laboratory devices can be divided into several types:

desktop;
clinical;
corner small;
portable;
stationary;
refrigerator;
vacuum with refrigerator;
supercentrifuge;
hematocrit;
preparative.

The most critical steps in clinical trials are centrifugation of blood to obtain plasma, serum and blood cells. Working on these devices seems simple, but in fact many mistakes are made in practice, when the results of the analyzes are inaccurate, the blood sample is lost.

If the parameters of this process are incorrectly selected, the results will be as follows:

increased hemolysis;
inefficient separation of blood components;
breaking glass containers;
opening caps of test tubes;
deformation of plastic test tubes.

If not observed temperature regime, then the concentration or activity of thermosensitive analytes is reduced, and if gel tubes are used, an unsuccessful separation of blood components will occur.

The following factors should influence the choice of a laboratory centrifuge:

types of analyzes performed (biochemistry, immunochemistry, hematology, gene diagnostics, cytology, etc.);
scope of research at KDL;
type of blood collection system;
types of samples (plasma, serum, blood cells);
security requirements.

When it comes to a small mobile research center or laboratory, where it is impossible to install a stationary model, then purchasing a benchtop laboratory centrifuge is a saving solution. Such a model is very compact, and there are many possibilities for a complete study. Their power supply is mainly carried out from the mains.

Self balancing effect

The self-balancing effect can be observed in centrifuges designed for wringing clothes. As the speed increases, the centrifuge first begins to shake, then the peak of shaking passes, the shaking decreases, and the centrifuge reaches operating speed.

If the laundry is too uneven, the self-balancing effect may not occur. In this case, it becomes impossible to reach the operating speed - the centrifuge goes into a “spread” (it starts to touch the body with the drum, making knocks).

The self-balancing effect is based on the fact that a body that does not have a rigidly defined axis of rotation rotates about its center of mass (for example, if you spin a ballpoint pen, or mobile phone).

Technically, this is implemented by an elastic suspension of the centrifuge drum (often together with a drive motor) to the main body of the device. An elastic suspension (usually rubber dampers) allows the centrifuge drum to move in the radial direction (in any direction) up to several centimeters. In this case, the tilt and axial displacements are fixed relatively rigidly.

During rotation, the drum tends to rotate relative to its center of mass, displacing the drive axis by a certain radius (equal to the distance from the axis to the center of mass). If this distance fits into the course of the elastic suspension, the centrifuge drum rotates about its center of mass, and the drive axis (and suspension) moves along a circle, which is described by the center of the drum. (Due to the small diameter of the circle and the high frequency of rotation, this movement is visually perceived as a vibration). When the position of the center of mass changes (uneven water extraction), the drum begins to rotate relative to this new center, and the drive axis and the suspension “accompany” the changed circular movements of the center of the drum.

Self-balancing, as a rule, is used in centrifuges with a vertical drum (the suspension device is simpler and a preliminary uniform arrangement of the material is possible), however, this effect (to some extent) is also used in automatic washing machines - it is not the drum and its drive that are elastically suspended in them, but the entire tank, which is possible due to the lower number of revolutions of the drum. When squeezing, the tank together with the axis of the drum makes circular movements (visible as vibrations), and the elastic suspension separates (and allows) these movements from the main body.

Also in centrifuges (in particular, on some automatic washing machines), it is sometimes used automatic balancing(during operation) - displacement of pre-fixed counterweights (under the control of electronics), to bring the center of mass of the drum to the geometric axis of rotation.

Centrifuges for laboratory purposes

Centrifuges for laboratory use are classified by the speed of rotation of the rotor or by the total volume of samples loaded.

By volume:

Microcentrifuges(treatment of eppendorf tubes, 1.5-2.0 ml each),
general laboratory centrifuges(total sample volume about 0.5 l),
specialized high volume centrifuges(usually up to 6 liters). An example of specialized centrifuges are blood processing centrifuges. The device of such a centrifuge is narrowly specialized for one task - the rotation of polyethylene containers with blood. Such a centrifuge has a high-powered motor, but the rotor speed is much lower than that of a similar centrifuge in terms of energy consumption.

Note that the centrifuge sample volume is calculated on the assumption that its density is 1 g/cm², if the sample density is higher than 1.2 g/cm², the volume of material to be processed must be reduced, otherwise the centrifuge may break.

By speed:

Microcentrifuges(processing of eppendorf tubes, usually does not require high speeds) - speed up to 13 400 rpm,
general laboratory centrifuges- have considerable versatility and can work with eppendorf test tubes and other containers; rotor speed from 200 rpm to 15,000 rpm,
high performance centrifuges they are high-speed- solve all possible laboratory tasks (except for ultracentrifugation); rotor speed from 1000 rpm to 30,000 rpm. Only two companies have mastered the production of such centrifuges: Beckman Coulter and Hitachi
Last speed category - ultracentrifuges rotor speed from 2000 rpm to 150,000 rpm. Such centrifuges are also produced only by Beckman Coulter and Hitachi.

By type of food (applies to Beckman Coulter):

single phase
Two-phase (the power cable contains conductors: L1, L2, L3, N, PE, however, the L2 line is cut off, therefore the centrifuges are two-phase, not three-phase).

If you are able to install your centrifuge on a table, then such a centrifuge will be desktop, if the centrifuge is large, has legs (rollers), such a centrifuge is most likely floor-standing. Floorstanding centrifuges require special attention during installation due to their significant power consumption up to 30A at 220V. They can be connected to a TT or TN-C-S power supply system. Connecting to a TN-C system has the potential for electrical shock. Incorrect connection of conductors L and N in the TN-C system will inevitably lead to a short circuit to the case and failure of the centrifuge.

The most famous brands of centrifuge manufacturers: Beckman Coulter, Hitachi, Eppendorf, Sigma, OrtoAlresa, Centurion Scientific.

Notes

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Synonyms:

See what "Centrifuge" is in other dictionaries:

Installation for centrifugation; the main part of the centrifuge is a drum (rotor) rapidly rotating around its axis. gas centrifuge centrifuge used to separate isotopes of uranium in the gaseous compound UF6 using a strong ... ... Nuclear power terms

- (from Latin centrum focus, center and fuga flight, running * a. centrifuge, centrifugal machine; n. Schleuder, Zentrifuge; f. centrifugeuse; i. centrifuge) a machine for separating pulps (suspensions) into solid and liquid phases under the action … … Geological Encyclopedia

centrifuge- Installation for the mechanical separation of heterogeneous systems consisting of two or more phases (suspensions, emulsions, aerosols) into component parts by the action of centrifugal force [Terminological dictionary for construction in 12 languages (VNIIIS Gosstroy ... Technical Translator's Handbook

Separator, centrifuge, erkensator Dictionary of Russian synonyms. centrifuge n., number of synonyms: 11 vibrocentrifuge (1) ... Synonym dictionary

CENTRIFUGE A rotating device used to separate substances. In laboratories, centrifuges separate particles of suspensions, for example, separating erythrocytes (red blood cells) from blood plasma. AT Food Industry centrifuges… … Scientific and technical encyclopedic dictionary

CENTRIFUGE, centrifuges, for women (from lat. centrum center and fuga flight) (tech.). An apparatus for separating a mixture (loose solids or liquid) into its component parts by the action of centrifugal force. Explanatory Dictionary of Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary of Ushakov

CENTRIFUGE, and, female. 1. An apparatus for mechanical separation of a mixture into its component parts under the action of centrifugal force. 2. A device that creates overloads under the action of centrifugal force (for testing equipment, training pilots, astronauts) ... Explanatory dictionary of Ozhegov

An apparatus for mechanically separating a mixture into its component parts under the action of centrifugal force. See also ultracentrifuge. (

All research medical centers and good hospitals are equipped with laboratories. Here, the staff examines the analyzes of patients, comes up with something new in the field of pharmacology and studies certain diseases. Without laboratory research, it would be impossible to study new ailments and fight them.

Each laboratory has different equipment. And a laboratory centrifuge is a device that is impossible to do without.

What is a laboratory medical centrifuge?

Any laboratory can work fully only when it has an optimal set of tools and instruments that are ready for regular use. A laboratory centrifuge is a device that is used daily in medical and scientific practice. The main task of this device is to separate substances by density and consistency using centrifugal force. Thus, the substances with the maximum specific gravity are placed in the periphery, and the fractions with the minimum specific gravity become closer to the axis of rotation.

In scientific and medical practice, it is quite common to separate various liquids into fractions using laboratory medical centrifuges. The liquid is placed in a special container, and after turning on the device, the centrifuge begins to rotate around its axis very quickly. As a result, homogeneous elements are formed - components of the original liquid.

What is centrifugation?

Centrifugation is the operation of a centrifuge. It is based on the law of physics about centrifugal force and allows you to decompose liquids into components as quickly as possible, which is impossible, for example, when settling, filtering or squeezing. The higher the rotor speed and the higher the intensity of its revolutions, the more efficient the device works.

Laboratory centrifuges with or without refrigeration are classified:

For low-speed devices in which the rotor frequency is 25,000 rpm.
High-speed units with a rotation speed of 40,000 rpm.
Ultra-high-speed centrifuges, in which the rotor speed exceeds 40,000 rpm.

What substances can be separated into particles using a centrifuge?

This device is designed to separate such biological fluids as blood, urine, lymph, mother's milk. These substances are heterogeneous, and when studying the analyzes of a sick person, one cannot avoid their easy separation using a laboratory centrifuge.

The most frequently examined, of course, is human blood. With the help of special centrifuges, you can prepare blood products, obtain blood serum suitable for transfusion, and much more.

In addition, this unit is designed not only for separating liquid substances into components, but also for separating solid fractions from liquids. Liquids, which include particles of varying severity, are easily distributed into components using a laboratory centrifuge. It can be not only blood or lymph, but also various suspensions.

Design features of the equipment

The above equipment is a drum equipped with holes of different diameters. It is in them that test tubes with test materials are installed at different angles. A fairly powerful centrifuge motor and a sealed lid ensure high-quality and full-fledged operation of the device.

The main difference between centrifuges is the design. It can be different and depends on the purpose for which this equipment will be used in the future.

Main elements of the device

Modern centrifuges used in laboratory and medical practice are equipped with many useful features, such as a timer, replaceable nozzles, a device rotation speed controller, and others. But the basic elements are unchanged, and these are:

Device body and sealed cover.
A special working chamber in which test tubes are placed.
Rotor.
Engine.
Remote Control.
Power Supply.

More expensive models may be equipped with a display, sensors, detector device, cooling system, automatic lid lock, etc.

Traditionally, manufacturers use stainless steel, polypropylene, aluminum, and various metal alloys in the manufacture of the case and hermetic cover. This ensures the durability of the equipment. Many of the materials used in the manufacture of this equipment are resistant to aggressive environments.

Aggregate classification

Centrifuges laboratory and medical have their own classification. Therefore, it is necessary to familiarize yourself with it before buying this device.

According to the type of unit, they are divided into general laboratory, hematocide and devices equipped with a cooling system. The first type of centrifuge is the most popular and widespread. The second is designed to conduct blood tests. Still others allow the test substance to be cooled during the analysis.

Devices are also classified according to the type and volume of working utensils. These can be: microcentrifuges (tabletop), small volume units, large volume centrifuges, floor options, universal centrifuges.

Do not forget about the functions of a laboratory centrifuge. There are machines with a low rotation speed, high-speed units, centrifuges that provide several functions, as well as ultracentrifuges.

How to choose a centrifuge?

When choosing a centrifuge for laboratory and medical research, there are several factors to consider.

First of all, it is necessary to decide what types of analyzes will be carried out using this equipment. In the field of biochemistry, hematology, immunochemistry, cytology, different devices with different technical characteristics and operating modes are used.

Next, you need to determine the scope of future research and what types of source materials you plan to use. It will be useful to take into account the safety requirements. If you plan to study small volumes of substances, then a microcentrifuge will be enough for these purposes.

For a small or mobile laboratory, there is no need to purchase bulky equipment, because in this case the amount of research will be small. As a rule, large centrifuges are equipped with a host of additional features that are most likely not to be used. No need to overpay. A compact benchtop laboratory centrifuge is the ideal solution for this situation.

Since its size is small, it will not interfere with other research activities. It is very simple and easy for her to provide power (connects to a regular outlet).

What technical parameters to pay attention to when choosing a device?

If you decide to purchase a centrifuge for quality laboratory and scientific research, then first of all pay attention not to the speed of rotation of the rotor. Typically, the rotor speed in most laboratory-type devices, for example, in the laboratory centrifuge TsLMN R-10-02 and others, does not exceed 3000 rpm (if we are talking about desktop models). Practice has shown that centrifuges with a speed of 4000 revolutions are most in demand today, since this value is sufficient for laboratory conditions.

The type of rotor can be horizontal or angular.

Find out how many test tubes are placed per tab in the unit. Specify the allowable volume of test tubes.

Paying attention to the above specifications, you can choose the best device at a good price. The price of units usually varies from 18 to 270 thousand rubles.

Where else are these units used?

Manufacturers of laboratory centrifuges have tried to make them multifunctional and every year they release more and more advanced models. This unit is an indispensable assistant in medical, chemical, experimental and even industrial laboratories. It allows you to accurately investigate the various compositions of substances.

AT oil industry such devices are used in the study of hydrocarbons, as well as in monitoring the quality of the road surface. Centrifuges are also used for ore dressing and in the production of washing machines.

In the agricultural sector, centrifuges are used to effectively clean grain, extract honey from honeycombs, and separate fat from milk.

Without a centrifuge, it is simply impossible to do without isotope fission in physics.