Vacuum pumps Types and characteristics. Turbomolecuular pump: history of creation, analysis of molecular and turbochasos, operation of TMN pumps and dry vacuum pumps

Catalog section of the screw dry vacuum pumps DRYVAC from Leybold GmbH (Germany)

Drink Vacuum Dryvac Vacuum Pump from Leybold GmbH (Germany)

The principle of functioning based on the rotationalists allows producing gas to pump without oil in the area. The DRYVAC screw Vacuum pump has a compression cavity, formed the surface of the housing, as well as two rotors that perform sync. Due to the fact that rotors rotate in the directions of the direct ability, there is a gradual movement of the compression cavity from the side towards the exhaust side, which ultimately ensure the effect of pumping effect.

Despite the fact that in the design under consideration, the process of the internal compression of gas, the "particle path" in the internal space of the pump is minimal. Such a feature is significant maintenance, and also reduces the need for service clocks to a minimum.

The DRYVAC line is a new series of oil-free devices based on screw vacuum pumps. A complete set that may be vain must be selected based on the scope of application, as well as other obvious criteria.

When developing a series, actual needs of the proprietary needs were taken into account, which presented to the system of vacuum pumping claims that sufficiently high. The device under considerations are used, in particular, making screens, photovoltaic elements, as well as for a number of industrial applications.

Each version of the pump from the DRYVAC line is equipped with water cooling, due to which the compactness of the design and is able to simply mounted even in complex systems in parallel with the Native Pump devices of the RUVAC series of the WH, WS and WA.

The line of screw vacuum pumps DRYVAC includes:

• model DV 450.
• model dv 450s.
• model DV 650.
• model DV 650-R
• model DV 650 S
• model DV 650 S-I
• model DV 650 C
• model DV 650 C-R
• model DV 1200.
• model DV 1200 S-I
• model DV 5000 C-I

The turbo pump (TMN) refers to special pumps that allow you to create a deep vacuum and for a long time, about 10 -2 to 10 -8 pa. This is the nature of the etymological value of the pump name. The "turbo-" prefix is \u200b\u200ba reduced option introduced into the technical lexicon since 1900, the term "turbine". These both words went from Franz. "Turbine" - "turbine", and earlier from the lat. "Turbo", meaning "to bring in a mess, outrage, whirlwind, top." The second part of the first word "- molecular" occurred from Lat. "Molecula" is "part, particle", as a diminutive from "Moles" - "Mass, boulder, bulk". The next term "pump" is invalid by our Slavic, as it transformed from the old-plating words "suck, elimaty, conaces", meaning "sucking breast milk", "sucking brain bones", "pull liquid".

In this article we will look at:

• tURBUMOLECHING PUFEIFFER PUM;
• turbomolecular pump Agilent TV81m;
• tWISTORR 84 FS High Current Turbomolecuce Pump;
• turbomolecular pump TG350F;
• power supply of turbomolecular pumps of type BP 267;
• turbomolecular pump principle of work;
• molecular vacuum pump;
• molecular pump MDP 5011 Price;
• buy turbo pumps;
• turbochase price;
• shortcomings of turbo pumps;
• turbomolecular pump TMN 500;
• pump TMN 200;
• dry pump;
• oilless vacuum pump;
• outless forvacuum pumps;
• dry type vacuum pump;
• oil-free plate rotor vacuum pump;
• vacuum piston oil-free pump;
• forkacuum pump 2NVR 5DM.

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In 1913, the German scientist Wolfgang Gedea published a description of the new vacuum pump in the journal "Annalen Der Physik", for which the laws of the molecular-kinetic theory of gas movement were used. For the purpose of experimental check, it made the first vacuum molecular pump with a minimum 0.1 mm gap between the rotor rotating at a speed of about 8000 rpm, and a fixed stator. Gas vacuum was obtained up to 10 -4 mm mercury pillars. The new pump even began to be produced by the German company "Leybold's Nachfolgers", but did not receive much spread. First, it did not have an emergency need, and secondly, technological difficulties were prevented with the manufacture of such small gaps. Macroscopic solid particles (pebbles, chips, glasses) (pebbles, chips, glasses) have led to the rotor.

In the late 1950s, interest in molecular pump resumed

Only in the late 50s of the last century, the interest in the molecular pump was resumed when the German engineer V. Becker invented the Turbomolecular vacuum pump Pfeiffer with a large number of blade discs on the shaft and with increased gaps, about 1 mm. This pump patented in 1957. Pfeiffer Vacuum. Next, the device and the principle of operation of the TMN pumps continued to be improved, such structures appeared like the Agilent TV 81m turbum and the newest (2015) high-cube Turbomolecuce pump Twistorr 84 FS Italian company Agilent Technologies, the hybrid turbocolecular pump TG 350F Japanese company Osaka Vacuum and others. In this case, the nodes of these devices are interchangeable. For example, the BP-267 turbomolecular pump power supply unit can be used for NW-340, NW-950, 01AB-450, 01AB-1500 models.

In the molecular pump, the pumping of the gas medium is carried out due to the message of the substance of the substance of the mechanical pulse pulses from moving at a high velocity of solid, liquid, gaseous surfaces of the pump. At the same time, in the molecular pump, the direction of movement of working surfaces and gas molecules coincide, and in the turbomolecentage - the direction of movement of the working elements and molecules are mutually perpendicular.

Image of the molecular pump in the context

Molecular pumps on the principle of action are divided into:

• mechanical (rotary and turbine);
• ejector;
• parses;
• gas resources;
• water-jet;
• diffusion.

For example, the high-tune molecular pump MDP 5011 is a device with mechanical working elements. The movement of the gas molecules to the outlet of the pump provides a solid surface of the rotor-cup that performs 27000 rpm. This model MDP 5011 is a sales leader among turbochasions. It is clear, you are interested in the price of the MDP5011 molecular pump. Contact us about such questions, call, write by email. We will advise and help.

Turbo pumps is a pumping device with a turbine drive, nodes and parts of which are included in the pump design. The following types of turbo pumps differ depending on the type of the pumped working medium.

Exterior of turbo-pumps

1. Turbochasos for pumping liquids.
2. Turbochasos for pumping suspensions.
3. Turbochasos for pumping gases.

The disadvantages of turbochasions include the complexity of the design, long-term downtime when repairing a pump or turbine, high cost. Therefore, if necessary, buy oil turbosasostmn-6/20, naturally, the question arises, what is the price of turbo pumps. If she does not suit you in other firms, come to us.

Turbomolecular pumps (TMN) are made in the form of multistage axial turbines, which ensure the achievement of medium, high and ultrahigh vacuum. The special design of the rotor and stator steps of the turbine, in which inclined channels placed by mirroring each other makes it possible to effectively pump out the gas molecule due to the different probability of passing molecules through the cornement channels in the direction of pumping and feeding. TMN is fixed on a massive base through shock absorbers, which reduces vibration in the process of pumping.

External view of the turbo-olecular vacuum pump TMN-500

The principle of operation of the turbomolecular pump is as follows. The energy of the turbine blades rotating with high frequency is transmitted by gas molecules. The latter face the surfaces of the blades, the fractions of the second move together and fly on a tangent to the rotating turbine. The summation of the kinetic energy blades with the thermal energy of moving particles of gas is occurring. Chaotic movement of molecules turns into an accelerated movement in a predetermined pumping direction. Such effective rotor action is possible only with the mode of a molecular flow of gas, which is created by an additional two-pressure forvacuum pump.

A good impression is produced by domestic two-flow oil-free pumps: the turbomolecular vacuum pump TMN-500 and the TMN-200 pump with a capacity of 500 and 200 l / s, respectively. Of course, according to the quality of assembly and design, they are inferior to foreign counterparts. But at low cost, it is characterized by reliability in work, reliability and sufficient durability.

Dry vacuum pump (oil-free) works similarly as oil. But in the dry type pump does not apply oil for lubricating the driving parts, and there are no sealing devices. Therefore, not metal, but a graphite composite material, as the material of the blades of dry pumps is used. Graphite blades are cheaper than metal from titanium, aluminum, stainless steel, are characterized by the exchange coefficient of friction and reliably seal the pump chamber.

Exterior dry vacuum pump

Advantages of a vacuum oil-free pump:

• the absence of water vapor when air outputs from the pump, the workplace becomes clean, the environmental environment is improved;
• no need to buy and pour expensive oil, monitor its level and contamination;
• lower cost.

Disadvantages of dry pump:

• the depth of the vacuum being created is lower than in the oil supplied pumps;
• the durability of graphite blades is significantly less than metallic;
• wear products in the form of dustless graphite fall into the atmosphere.

However, experts believe that the future of oil-free vacuum pumps. And now they are trying to buy an oil-free plate-rotary vacuum pump, a oil-free piston vacuum pump, a dishwasher vestacuum pump, not paying attention to their price. Since the simpler and cheap operation of the dry pump will pay off all the initial costs.

The forvacuum pump is a device for creating an initial vacuum - forvacuum (from it. "VOR" - "Before, ahead of the vacuum and lat." Vacuus "-" empty "). The principle of operation is that the forvacuum pump is set as the first stage in the pump system, creating a high and ultrahigh vacuum. Provides electricity savings and improves the possibility of using the next high stage pump.

The most suitable for this domestic lamellar-rotary forvacuum pump 2NVR-5DM, designed both to create a low and medium vacuum independently and as an auxiliary pump.

Appearance of the forvacuum pump 2NVR-5DM

If you are interested in the described turbomolecular and forvacuum pumps from the range of our company, you can get more detailed information from consultants. Our highly qualified specialists will help in choosing the optimal version of pumps, explains the terms of purchase, operation and service, justify prices. Write you help in the selection of spare parts and auxiliary materials, such as the blades for becker oil-free pumps, oil for the forvacuum pump and others. Call our phones or contact e-mail. We will be glad to help you.

Main the principle of the vacuum pump of any type - This is an outstanding. It is the same in all vacuum pumps of any size and any way of application. In other words, the principle of the vacuum pump It comes down to removing the gas mixture, steam, air from the working chamber. In the process of displacement, the pressure changes, and the gas molecules are flowing in the desired direction.

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Two important conditions that the pump must complete is to create a vacuum of a certain depth, by pumping out the gas environment from the required space and do it during the specified time. If some of these conditions is not executed, then you have to connect an additional vacuum pump. So, in the case of the insecurity of the required pressure, but for the desired time interval, a forvacuum pump is connected. It additionally reduces pressure to fulfill all the necessary conditions. This principle of operation of the vacuum pump is similar to a consistent connection. Conversely, if the pumping speed is not provided, but the desired vacuum value is achieved, then another pump will be required, which will help to achieve the necessary vacuum faster. Such a principle of operation of the vacuum pump is similar to parallel connections.

Note. The depth of the vacuum created by the vacuum pump depends on the tightness of the working space, which create the elements of the pump.

To create good tightness of the workspace, special oil is used. It seals the gaps and completely overlaps. A vacuum pump having such a device and the principle of operation is called oil. If the principle of the vacuum pump does not provide for the use of oil, then it is called dry. The advantage of using dry vacuum pumps are used, as they do not require maintenance with oil replacement and so on.

In addition to industrial vacuum pumps, small pumps that can be used at home are widespread. These include a manual vacuum pump for pumping water from wells, reservoirs, pools and other things. The principle of operation of the manual vacuum pump is different, it all depends on its type. These types of hand vacuum pumps differ:

1. Piston.
2. Rod.
3. Wing.
4. Membrane.
5. Digid.
6. Hydraulic.

Piston vacuum pump Works at the expense of the movement within it, the piston with valves in the middle of the case. As a result, the pressure decreases, and water through the bottom valve rises up while the piston handle lowers down.

Rod vacuum pump Looks like a principle of action on a piston, only the role of the piston in the case performs a very elongated rod.

Wing vacuum pump It has a completely different principle of action. The pressure in the pump working chamber is created due to the movement of the impeller with the blades (impeller). At the same time, the water rises along the chamber wall, it increases pressure and, water splashes outward.

More complex design is rotary vacuum pump. But this complexity is compensated by the fact that the pumping capacity includes pumping not only water, but also of heavier oil fluids. The pressure in the pump creates a rotor with thin plates, which rotate and with the help of centrifugal force are drawn fluid into the container, and then the physical strength pushes it.

Membrane vacuum pump It does not have any rubbing parts, so it can be used to pump very dirty mixtures. With the help of an internal pendulum and membrane, a vacuum is created, which moves the liquid through the case to the required place. In order for the body does not jin from the delayed random garbage, the pump is equipped with special valves that purify the pump.

Depth vacuum pump Can lift water from very much depth (up to 30m). The principle of its work is the same as the piston, but with a very long rod.

Hydraulic vacuum pump Well pumps viscous substances, but he did not receive wide use. In more detail, the principle of operation and the device of vacuum pumps will look at its separate views.

Principle of operation of water soluble vacuum pumps

One of the types of vacuum pumps - a waterproof vacuum pump, the principle of operation is based on the creation of the tightness of the working volume with a liquid, namely water.

Consider a detailed waterproof vacuum pump and its principle of operation. Inside the housing of the waterproof pump is a rotor, which is shifted relative to the center a bit up. The rotor placed the impeller with blades rotating during operation. Water pumps inside the housing. When the wheel moves, the blades capture the water and the centrifugal force cast it towards the body. Since the rotation speed is quite large, the result is a water ring around the circumference of the case. In the middle of the case, free space is obtained, which will be the so-called working chamber.

Note. The tightness of the working chamber provides the surrounding water ring. Therefore, such pumps are called water-folk vacuum pumps.

The working chamber obtains a gray-shaped form, and it is separated by the blades of the wheel on the cells. These cells are obtained different sizes. During the movement, the gas moves alternately on all cells, heading towards a decrease in volume and simultaneously compressing. This happens a large number of times, the gas is compressed to the required value and extends through the injection hole. When gas passes through the working chamber, it is cleared and comes out out already clean. This property turns out to be very useful for pumping polluted media or saturated ferry gas media. The vacuum pump during operation constantly loses a small amount of working fluid, so in the design of the vacuum system, a water tank is provided, which then on the principle of operation returns back to the working chamber. This is also necessary because the gas molecules shrinking give their energy to water, thereby heating it. And in order to avoid overheating of the pump, the water is cooled in such a separate reservoir.

It is possible to see in detail the vacuum pump and the principle of its work can be on the video proposed below.

Work plate-rotary pumps

Plate-rotor vacuum pump refers to the number of oil pumps. In the middle of the case there is a working chamber and a rotor with holes, which is located eccentric. The rotor has blades that can move along these slots under the influence of springs.

Having considered the device, now consider what rotary vacuum pumps have the principle of operation. The gas mixture enters the working chamber through the inlet, moves along the chamber under the influence of a rotating rotor and blades. The work plate, repulscing the spring from the center, covers the inlet, the volume of the working chamber decreases, and the gas begins to shrink.

Note. During the compression of the gas, condensate is possible due to the saturation of steam.

When compressed gas comes out, the resulting condensate comes out with it. This condensate may not affect the work of the entire pump, therefore, in the design of plate-rotary pumps, it is still necessary to provide a gas-flavored device. Schematically see how the rotary-plate vacuum pump works, the principle of operation of it is, in the figure below on the example of the BUSCH R5 pump. As already mentioned, a plate-rotary pump is an oil pump. The oil is necessary to eliminate all the gaps and cracks between the blades and the case, and between the blades and the rotor.

The oil in the working chamber is mixed with the air medium, compressing and exits in the oil container. The air mixture easily moves into the upper chamber of the separator, where it is finally cleaned from the oil. And the oil whose weight is greater, settles in oil tank. From the separator, the oil returns to the inlet.

Note. High-quality pumps clean the air very carefully, oil losses are practically no, so it is necessary to pour oil into such pumps extremely rarely.

Principle of operation of the pump entry

Water vacuum pump, the principle of operation of which is the same as the waterproof vacuum pump.

The working fluid of pumps is Water. The diagram you can see a simple principle of the pump operation of the pump.

The movement of the rotor of the pump is engaged directly by the engine through the coupling. It provides large rotor revolutions, and as a result, the possibility of obtaining a vacuum. True, vacuum pumps are enveloping only low, because of this they are called low pressure pumps. Simple VNN pumps can pump out gases saturated with pairs, contaminated media, and at the same time clean them. But the composition should be non-aggressive so that pig-iron pump parts are not damaged as a result of a reaction with the chemical composition of the gas. Therefore, there are models of pumps in VNG, the details of which are made of titanium alloy or nickel-based alloy. They can pump up a mixture of any composition, without fearing the occurrence of damage. The pump is posted, by virtue of its principle of operation, it is performed only in horizontal execution, and the gas enters the chamber from above along the axis.

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The plate pump is a mechanism that is very unusual in its structure, because of which many are afraid to buy such a type of devices. Often, lamellar pumps are divided into two main types:

• Double action
• Single action

Both variants are based on key nodes consisting of plates and rotor.

Plates inside the system are moved exclusively in the radial direction, as only in this way, it is possible to achieve the desired level of performance. If we talk about the differences between two categories of plate pumps, then they are consisting only in the very form of the surface of the stator, which is slightly different from each other in terms of its design.

Double Action Plate Pumps

The stator in such a mechanism most often acts as an oval, which allows the device to work as evenly possible. This is achieved due to the fact that all plates inside the system for one turnover of the shaft have time to do two clocks at once.

In such a device, there is also a certain zone in which the gap between the stator and the rotor is simply minimal. In this section of the system, certain voltage jumps can occur with which special sensors are very well coped, which regulate all similar questions.

As for the inner plates, they are constantly under pressure and pressed against the inside of the working stator. It is this density that allows you to achieve the highest level of tightness, which is also very important for the quality of the system.

But this is still far from the limit, so the turn of the stator is only the beginning, after which such a procedure will be done several times. After the turn continues, a vacuum is formed inside the system, which allows you to continue the workflow. During this process, the device's working chamber is already connected to the suction line, and this connection occurs with the assistance of the distribution disk, which by the way it is quite well coped with its task.

After the volume of the working chamber reaches the maximum volume, its connection to the suction line is completely interrupted. If the rotor continues to rotate, it means that the device works in the correct mode and the volume of the working chamber should gradually decrease. Further, the system's working fluid flows out of the system through the side slot and heads towards the pressure line, where there is a completely new process.

A considerable role in the whole process also plays the force of clamping plates to the Rothor. This indicator is determined using the pressure emanating from the internal mechanism. That is why, most often, such installations in the standard configuration have two plates operating at the same efficient frequency.

Plastic Pumps Single Action

In this system, the movement of the plates has certain limitations that end at the level of the stator having a cylindrical surface shape. The unusual location of the stator in the system allows the internal elements of the system much more efficiently.

In this system, as in fact, all others exists a process of filling the working chamber, which is very similar to what we are accustomed to see in ordinary installations. But despite this, the workflow itself of this unit is fundamentally different from the fact that we are often visible in ordinary installations.

So before buying it is necessary to think about which unit you need, and what is the key goal of buying such equipment. Thinking all this in advance, you can completely secure yourself from a rampant purchase.

Plaques vacuum pump

The plate vacuum pump is an already upgraded version of this unit, which has a large number of advantages that you simply cannot be seen in the usual version of the pump. The main advantage of this installation is the possibility of its work in the conditions of ultra-high vacuum, which is currently very appreciated in the modern market.

Now we will look at the advantages and disadvantages of lamellar vacuum pumps, so that it is still to understand whether to overpay for work on a vacuum basis.

Advantages of vacuum lamellar pumps:

• Ability to form an ultrahigh vacuum
• High level of productivity
• Wider range of applications
• The ability to perform multiple processes at the same time

Disadvantages of vacuum lamellar pumps:

• Too large dimensions that can not always be accomplished in the right place
• High noise and vibrations during operation

After reviewing the advantages and disadvantages, we can conclude that the advantages of vacuum lamellar pumps are still more, and if you still decided to take a more productive unit, then the vacuum plate pump is just the best option for which you really should be overpayed.

Plate Rotary Pumps

Plate-rotary pumps are now very popular in the market, and many manufacturers of various products are ready to give a lot of money for buying yourself such equipment. If we consider the entire range of lamellar pumps, then it can be found both expensive installations and more budget.

Now we will look at the most successful version of the plate-rotor pump, which will be most practical in terms of price and quality.

The RZ 6 plate-rotary pump is a device that managed to combine not only high technical characteristics, and also the quality of assembly, stability in work, a small value and even a huge number of important points that should always remember.

If we talk about the scope of application of plate-rotor pumps, then it can be noted that they are used in a wide variety of industries. Now we will look at those areas of industry, where at the moment they have become a key element, without which production could not be the same.

Scope of applying plate-rotary pumps:

• Radio engineering industry
• Chemical industry
• Petroleum production

Each of these industries at the moment is in dire need of lamellar-rotary pumps, which at the moment have become an integral part of the work in all these directions.

Oil pumps

If you judge by the type of pumps, which found its greater use in most industries, it is certainly possible to say that these are oil pumps. It is this category of devices at the moment is the most popular, as most users are used to trusting proven structures.

Now the dry pumps are increasingly popular, but still far from everyone is ready to overpay, while knowing that they are buying not quite proven technique. As for oil plants, they have long managed to establish themselves in the market and prove that they are able to work in a variety of conditions, issuing steadily high performance performance.

At the same time, users are also confident that such a technique thanks to constant lubrication is more reliable, and its internal parts will not be to wear.

Dry oil-free vacuum pump

A dry oil-free vacuum pump is an air-based device that allows it to minimize the threat of overheating, which can happen due to the lack of oil in the system. Recently, many have become inclined precisely towards dry vacuum pumps. The main reason for this is a new work technology that does not require constant lubrication or adding any fluid.

All that is required from the user is to turn on the vacuum pump, after which it can work without any interruptions. But still do not forget that this is a technique and it is necessary to constantly look after it. Having done all the necessary procedures for this device, you can be sure that it will serve you for many years and during this time its internal details will remain fully and will issue all the same high performance indicators.

Oilless (dry) Plate-rotor vacuum pumps belong to bulk pumps, allowing to obtain a vacuum of medium depths with the complete absence of oil exhaust in the outdoor. The depth of the vacuum achieved is from 90 to 400 mbar of residual pressure depending on the model. Which ranges from 9 to 40% of atmospheric pressure.

Create a good oil-free plate-rotary pump is quite difficult, so the number of manufacturers in the world is not so large. Basically, they are done in Europe (, and). And only pumps of small performance are produced in the USA, in China and Taiwan. Taiwanese pumps are used among the latter in the greatest demand.

Operating principle

Dry plate-rotary pumps are generally the same principle of operation as. They also use an eccentric installed rotor with plates capable of sliding freely in their grooves.
Animation 1: Principle of operation of a plate-rotor pump

However, there are some differences. In dry pumps, oil is not used to seal the gap between the blades and the housing, nor for lubricating the moving parts, nor for cooling. Therefore, the blades of dry pumps are not made of metal, but from a graphite composite. Graphite creates much less friction compared to the metal, so does not require strong cooling. In addition, graphite blades quickly take place to the surface on which they slide, providing good sealing of gaps between the case and the blades.

On the one hand, the design of oil-free pumps is simpler: no oil separator and oil canals. On the other hand, no lubrication increases requirements for surface processing.

Pros and disadvantages of oil-free plate-rotor vacuum pumps (compared to oil)

The main reasons for which it is worth choosing a dry plate-rotor pump, two: relatively clean air at the exit and the possibility of working with a rough vacuum for a long time. In addition, there is no need to constantly monitor the oil level and take care of the drainage of the pumped gas.

All the advantages of dry pumps are a mirror image of the shortcomings of the oil-shred models: if the oil is preferably preferred in the support mode of deep vacuum, then the dry pump can work with a rough vacuum at the input. The situation often arises when the failured air remains in the same room where people work. Having passed through the oil-shred model, the air is inevitably saturated with pairs of oil, which not only smells unpleasant, but is not particularly useful for others. Filters on the exhaust line to some extent solve this problem. But ideal filters do not happen.

On the other hand, passing through an oil-free rotary pump, the air although it does not remain perfectly clean, but in this case, instead of oil in the air, particles of graphite dust fall into the air. This dust, firstly, is distinguished significantly less than oils. And secondly, graphite does not smell, and it is much easier to filter. Therefore, an oil-free pump is a good choice for premises where people work.

Another significant lack of oil-shred pumps is the need for continuous control over the oil level. This level can be increased, due to the appearance of condensate, and decrease, for example, when working with a coarse vacuum or when the temperature is exceeded. Any of these scenarios are destroyed for a lamellar oil pump: if the oils are not enough, it will overheat and burn, and if there is a lot of condensate in the oil - the pump quickly rusts. An oil-free pump was initially deprived of these flaws: there is no need to keep track of constantly, it is enough to check the thickness of the blades once every 2-3 thousand working hours.

In general, for residual pressure above 400 mbar, an oil-free pump is a good choice. But to create a deeper vacuum, it is no longer suitable. The most advanced models from our catalog can provide only 100 mbar of residual pressure. Another limitation is the service life. Oil-filled models can produce the same performance for years (only occasionally pour oil), which is used by many laboratories, day and night supporting a stable vacuum in a laboratory cabinet. A dry plate-rotor pump can also work in 24/7 mode, but as the blades abrasion, its performance will fall. Therefore, this pump is recommended to include exactly when it is needed, and turn off at the end of the shift.

Wear workers plates

As can be seen from the animation above, the working plates are constantly moving on special grooves in the rotor. Extraked under the action of centrifugal force, they firmly adjacent to the walls of the camera and share the free space of the working chamber into several isolated volumes.

The rotor of the pump is spinning at high speed (usually 1400-1500 revolutions per minute, since 4-pole electric motors are used), so the problem of friction of plates about the inner surface of the working chamber occurs. In pumps with oil lubricant, this problem is not sharp, so the working plates (blades) can be both composite and more durable metallic. However, in dry pumps, the plates can only be from the graphite composite (Carbon Vanes). Graphite itself is a good lubricant - graphite plates slide on the working chamber without overheating. But at the same time graphite is relatively quickly engaged. With that, it is reduced not only its length from friction on the pump housing, but also its thickness from friction on the rotor decreases.

Image 1. Three types of wear of graphite blades of plate-rotary pumps.

The depreciation of graphite blades (plates) leads to air leaks and a decrease in vacuum depth, as well as pump performance. What is the average service life of blades of oil-free pumps? Most manufacturers do not specify this period. However, we own some information.

Taiwanese Stairs Vacuum indicate the need to replace the blades through 8,000 - 10,000 hours. At the same time, they note that the performance of any oil-free plate-rotary pumps begin to decline after 3,000 hours of operation.

The Italians DVP write about the service life of the plates of 10,000 hours. To our office somehow came the engineer, who worked the SB pump 16 of this Italian company. He told that the pump worked from 20,000 hours (although in the compressor mode, but it does not change the essence), after which it stopped working normally (it was about wear of the blades, and not about breaking the pump). In this case, the exhaust hoses inside were covered with a thin layer of graphite dust. This example says that the manufacturer indicates the minimum guaranteed service life of the blades, in practice they can work and more, but when the operating parameters are reduced.

The Germans of the BECKER series VX, KVX are record holders for the service life of the blades (alas and at the price of pumps too) - at least 20,000 hours, in practice from 20 to 40 thousand.

Image 2. A graph of reducing the performance of dry plate-rotary pumps due to wear of the blades.

At what depth of the vacuum efficiency of the PDA plate-rotary vacuum pumps becomes the greatest

The efficiency of oil-free lamellar pumps is not a fixed value, and depends on the working point (vacuum depth). At the pressure at the entrance is close to the atmospheric (with a rough vacuum) of the pump, the pump is very low and becomes acceptable (40% and higher) at a vacuum depth of 300 mbar (700 mbar of residual pressure). The maximum (almost 60%) of the efficiency reaches 600-700 mbar (300-400 mbar of absolute pressure), and then again begins to decrease to 40% as the vacuum is deepened.

Image 3. Comparison of the efficiency of a dry plate-rotor vacuum pump and a vortex single-stage blower.

If you compare, for example, a oil-free plate-rotor vacuum pump and a single-stage vortex blower running in vacuum mode, it turns out that these 2 devices do not compete with each other, and mutually complement. In the range of pressure generated from -100 to -300 mbar, the vortex blower shows the best efficiency of the efficiency, and in the range from -300 to -900 mbar, there is much more effectively a plate-rotor device.