Vacuum type internal compression scroll pumps are electromechanical devices that are widely used in science and industry. The scope of their use includes certain technological processes, as a result of which a deep vacuum is created. The average productivity of devices is up to 35 cubic meters / h. Due to the presence of a completely dry environment, such a pump can also be used for pumping active gases. Consider the features and benefits of this equipment.
History of Creation
The first attempts to create a spiral pump can be considered the measurement of atmospheric pressure readings, carried out by an Italian physicist named Torricelli. After studying the information received, he concluded that there was a vacuum, soon proving his hypothesis.
The classical design of the device in question was created at the beginning of the 18th century according to the project of the French engineer Leon Croix. The scientist developed a mechanism based on a rotary device with two constant-pitch spirals. At the same time, one of the elements remains stably fixed and is attached to the body. The second spiral slides in the inner part along the orbital path.
Serial production of spiralvacuum pumps have been established since 1980. The first models provided air extraction and pressurization for motors and air conditioners. Now the scope of use of such compressors has expanded significantly, including economic activity, space engineering, and industry. Spiral modifications are mainly operated in laboratories and enterprises.
Features
Two spirals are located between each other at an angle of 180 degrees. They create crescent-shaped compartments in which the movement of gas is provided by the pressure difference in them. An electric motor transmits torque to the shaft, after which the spirals make an orbital movement, and the volume of gas, gradually shrinking, tends to the central part.
Such devices belong to the class of fore-vacuum scroll pumps of dry type with internal compression. The design does not provide for the use of oils to seal mating elements. The pumps in question can be operated in conditions with a high probability of condensation.
Pros
Main advantages of scroll pumps:
- The complete absence of oil vapor allows the use of devices to create chemically pure components in a vacuum.
- During operation, abrasives do not accumulate in the interior, which prolongs the life of mechanical parts, ensuring a high stability coefficient.
- Lack of noise and low vibration makes it possible to use the device in rooms where there are people.
- Starting and starting the pumprequires minimal effort.
- The device is lightweight, does not require a special frame or frame for transportation.
- Compact. There are even desktop modifications.
- Reliability of mechanical components and electronics.
- The units are equipped with special systems for bearing sealing, shaft sealing, dust and solids removal.
- High efficiency (about 95%).
- Wide operating pressure range and high precision pumping option.
- Emitted heat is minimal, there is a full-fledged atmospheric cooling system.
- Almost all models are equipped with an hour meter, do not require complex and costly maintenance.
Package
The design of the scroll pump varies by manufacturer, but any design includes basic elements, namely:
- Forged iron body, semi-thick coated.
- Stand (distance to the movable scroll is from 0.05 to 0.01mm).
- Counterweight mechanism.
- Moving part that makes orbital rotation.
- Anti-jamming device.
- Eccentric shaft (electrically driven).
- A bellows that seals joints to prevent the introduction of oil vapors.
- Grease resistant rubber seal.
How does it work?
The principle of operation of the scroll pump is toexpulsion of gas from the peripheral part to the center using a movable element that creates two series of crescent-shaped volumes. The volume is then pumped through the steam room and the hole in the middle of the end plate of the fixed bed.
The number of rotations of a full working cycle with one portion of gas is identical to the number of turns of the spiral. For this, the involute, the Archimedes spiral, various arcs of circles and their variations are used.
The main difference between the operation of the unit in question is that suction, compression and discharge are carried out synchronously, simultaneously in several cavities. Diffusion of gas between low and high pressure sectors is reduced due to the separation of volumes between them. This decision made it possible to completely abandon the use of discharge and suction valves.
Anest Iwata Scroll Pumps
These units have been produced by a Japanese company since 1990. These pumps are used in a variety of applications, including vacuum furnaces, laboratory equipment, ion processing, sputtering systems. The device features a well-balanced mechanism, low pulsation and noise, and is well protected against oil or particles entering the vacuum chamber.
Brief characteristics on the example of modification Anest Iwata ISP-90:
- Cooling type - air.
- Pumping speed - 90 l/min at 50 Hz.
- Maximum vacuum - 5 Pa.
- Power consumption - 0.15 kW.
- Noise level - 52 dB.
- Weight - 13 kg.
- Dimensions –308/182/225 mm.
- Working voltage - 220 V.
XDS35i Oil-Free Scroll Vacuum Pump
This instrument uses the patented bellows motion input technology to completely isolate the bearings from the working compartment. This design eliminates the ingress of chemically active and oily components into it. The logical interface port allows you to adjust the shaft speed.
Parameters:
- Productivity - 43 m3/h.
- Pumping to the maximum - 35 cubic meters / h.
- Outlet pressure limit - 1 bar.
- Motor power - 520 W.
- Operating temperature is 10-40 degrees.
- Weight - 48 kg.
- Noise - 57 dB.
Application
Spiral centrifugal pumps are successfully used in various fields. Below is a list of the main destinations:
- In medicine - for cleaning components of various substances under almost complete vacuum (ventilators and artificial respiration).
- In pharmaceuticals - for the disinfection of drugs (antibiotics) from the waste products of microorganisms.
- In industry - as a fore vacuum device when assembling turbomolecular or diffusion type pumps.
- For conducting physical research in the study of photosensitive polymers and rarefied gases.
- Btests - to simulate weightlessness and undulating vacuum (when testing satellites, weather balloons, orbital modules, aircraft, rockets).
- In biological research - to study the effect of vacuum on various life forms.
- In microelectronics - for the manufacture of semiconductors under conditions of leveling of the oxidative action.
- In the chemical industry - to create a constant flow of raw materials (splitting of material into fractions, for example, when creating esters).
- In the food industry, the packaging of goods in a plastic sleeve.
- In the manufacture of complex optical-mechanical devices (electron microscopes).
In closing
The above list is not all areas where the vacuum scroll pump is used. Such equipment greatly facilitates a variety of activities. Especially the device is irreplaceable in cases when creation of oil-free vacuum is required. It should be noted that this direction is prevailing in the industry of development and production of pumping equipment. Due to the wide possibilities and design features, models are made, both industrial design and compact (desktop) versions.
