The working part of the vibrator is a bar shaped hollow cylinder, which is equipped with an eccentric vibrator inside. It rotates at a high speed driven by the motor to generate high-frequency micro amplitude vibration. The vibration frequency can reach 12000~15000 times/min. The vibration effect is good, the structure is simple, and the service life is long.It is suitable for vibrating beam, column, wall and other components and mass concrete.
1. Function and classification of concrete vibrator
(1) The function of concrete vibrator.
useConcrete mixerWhen pouring the mixed concrete components, the bubbles must be removed and tamped to make the concrete tightly combined and eliminate the honeycombs and pits of the concrete, so as to improve its strength and ensure the quality of the concrete components.Concrete vibrator is a kind of equipment that generates frequent vibration through a certain device as the vibration source with the help of power, and transmits this vibration to the concrete to vibrate and compact the concrete.
(2) Classification of concrete vibrators.
There are many kinds of concrete vibrators.It can be divided into internal vibrator, external vibrator andSurface vibratorThree kinds;According to the power source of vibrator, it can be divided into electric type, internal combustion type and pneumatic type, with electric type being the most widely used;According to the vibration frequency of the vibrator, it can be divided into low frequency type, medium frequency type and high frequency type;According to the principle of vibration generated by vibrator, it can be divided into eccentric type and planetary type.
2. Concrete vibrator
(1) Concrete internal vibrator.
1) Scope of application.The internal vibrator of concrete is applicable to all kinds of concrete construction, including plastic, flat plastic, dry hard, semi dry hard and concrete tamping with or without reinforcement.
2) Classification.The internal vibrator of concrete is mainly used for concrete vibration equipment in beam, column and reinforcement densified area. The common internal vibrator is electric flexible shaft plug-in vibrator.
(2) Concrete surface vibrator.
There are many kinds of concrete surface vibrators, of which the most commonly used is the flat surface vibrator.The plate type surface vibrator is directly placed on the concrete surface, and the vibration wave generated by the vibrator is transmitted to the concrete through the fixed vibration base plate.Since the vibration wave is transmitted from the concrete surface, it is called surface vibrator.When working, two people hold the handle of the vibrator and drag it as required.It is applicable to concrete with large area and small thickness, such as precast concrete construction slab, pavement, bridge deck, etc.[1]
Pneumatic vibrator
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Pneumatic vibratorThere are many manufacturing materials, including carbon steel, cast ironaluminium alloy, bronze, stainless steel and extruded aluminum, etc.For applications in special environments, such as the pharmaceutical industry, the housing can be made of aluminum or stainless steel.Its vibration frequency and vibration force can be precisely controlled by adjusting the flow and pressure of compressed air (stepless adjustment).Its main advantages and uses are as follows:
1. Only compressed air is needed as the power source, so the air consumption is small, which is safe and energy-saving.It is an ideal device for use in freezing or high temperature environments. It is suitable for humid, dry, dusty or explosive environments.
2. Small size, few faults, simple installation and maintenance.
3. Quick stop or start, suitable for manual or automatic systems.
4. The vibration force, frequency and amplitude can be adjusted freely during the movement.
5. It is widely used for fatigue test of parts or structural parts;Jitter and compaction of hopper;Linear and bowl feeders, screens and screens;Vibrating table and mixing equipment.
6. The service life of most types of pneumatic vibrators is relatively low.
Such as filling machine, coating machine, leak meterFeeder, conveyor belt, dehydration separation, particle suspension, etc.It is widely used in powder processing industries such as food, medicine, chemical industry, pesticide, feed, ceramics, glass, cement, fuel, etc;There are many models to suit.
working principle
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Schematic diagram of working principle of vibrator
The schematic diagram of the working principle of the electromagnetic vibrator is shown in the Diagram of the Working Principle of the Vibrator.stayElectromagnetic vibratorThere is an electromagnetic coil in the. The current passing through the electromagnetic coil is the pulse current passing through the half wave rectification.At the positive half wave, the current passes through, and the electromagnet has attraction to attract the vibrating plate close;In the negative half wave, no current passes through, and the electromagnet attraction disappears. Due to the action of the spring, the vibrating plate returns to its original position, and the coal feed tank is connected with the vibrating plate. Thus, under the action of the electromagnetic vibrator, the coal feed tank continuously vibrates.[2]
Advantages and disadvantages
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advantage
The production process is simple, the manufacturing cost is low, and the price is cheaper than the pneumatic vibrator.When in use, it only needs to be connected to the power supply, plug and play, and there is no air source storage process of pneumatic vibrator.
shortcoming
becauseElectric vibratorDue to the particularity of its structure, its service life is much shorter than that of ordinary motors. The following defects are the causes of burning, such as phase loss, overload, overcurrent, high temperature and dust.Short circuit, electric leakage and other faults will cause the electric vibrator to be burned, causing losses, affecting production and causing safety accidents.[2]
Application of vibrator
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A large number of hot-dip galvanizing enterprises apply vibrators in different processes of hot-dip galvanizing production.With regard to the application of vibrators, the rationalization proposal group of the Technical Committee specially organized a meeting to discuss this topic and gave the following suggestions.The use of vibrators to cause vibration and swing of hangers and racks will lead to changes in the flow mode of treatment liquid and zinc liquid.At present, almost all vibrators are installed between the crane hook and the galvanized hanger (or hanger), or installed on a separate hanger.Generally speaking, the vibrator is driven by two motors, which rotate synchronously in opposite directions.This unique setting eliminates lateral vibration, resulting in only vertical vibration.
Vibrators are not always advantageous, and their use depends on operating conditions and the type of parts to be plated.In most cases, the application of vibrators can improve the quality of plated parts and save rework costs.Vibrators can be used in different processes of hot-dip galvanizing.
1) Pretreatment phase.The short time vibration when the workpiece moves out of the liquid tank and the dripping is near the end can ensure more dripping of the treatment liquid, which can save time and reduce the carrying out of the treatment liquid.
2) In a zinc bath.Vibration helps to float the zinc ash in the zinc bath and the residual product of the plating aid on the surface of the workpiece, which may reduce the drying time, reduce the thickness of the zinc coating, and improve the quality of the zinc coating;The unavoidable contact points between workpieces and between workpieces and hangers can be minimized by vibration.
3) Above the zinc bath.Vibration is conducive to the reflow of zinc liquid on the surface of the workpiece to avoid the accumulation of zinc on the surface of the workpiece;It is beneficial to prevent the formation of zinc strips or zinc nodules, and avoid the formation of zinc spikes due to zinc strips or zinc nodules;The possibility of bonding between workpieces is reduced;Prevent zinc blockage in some small holes;Holes and internal threads become cleaner.
4) During slag removal.The slag bucket equipped with a vibrator is conducive to slag bailing;The vibration in the process of removing the slag bucket from the zinc bath below the liquid level and opening the bucket after removing the slag bucket is conducive to complete slag bailing and clean slag removal.
Fundamentally speaking, vibrators are more suitable for small and light workpieces than for heavy workpieces.Of course, the application of vibrator may also cause some defects, mainly because:
1) The vibration time is too long or vibration occurs in the process that does not require vibration.
2) The installation and fixing method of the parts to be plated is incorrect (hanging and fixing small parts with wire, which is easy to cause resonance).
In any case, as long as the vibrator is used, even if the damper is installed, the lifting system will produce greater stress.Therefore, it is necessary to check and evaluate whether the lifting unit can bear excessive load.
According to the structural size of the vibrator, it is estimated that it will occupy about 50cm of lifting height space.In some special occasions, the vibrator can be integrated on the hook of the lifting appliance, so that the original hook and lifting space height can be maintained.As for the operation of the vibrator, in order to meet the expected effect, the frequency of the vibrator used is not invariable.In view of this, many operators tend to choose a few small operating frequencies, which may cause some effective vibration frequencies to be missed in the production process.The application of several short vibration periods usually translates into a long vibration period.[3]
