Historical background of the hottest pneumatic vib

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The historical background of pneumatic vibrators

even today, some parts of the world still use manual impact hammers as tools for tamping concrete in the mold as they did centuries ago. Similarly, hammers are used to assist the flow of materials

the sieve used to separate corn kernels and corncob debris is considered to be the first industrial application of the vibrator, that is, the first non human driven vibrating element, such as the use of wind energy, water conservancy, etc

pneumatic vibrators came into use in the form of linear piston vibrators or pneumatic hammers at the beginning of this century. Only a few years later, a simpler rotary vibrator with a rolling sphere or rotor was born. In the past decades, this design has never changed; The shell of vibrators produced by most manufacturers is still made of cast iron, and the appearance is not processed

at the end of the 1960s, aluminum was used as shell material for the first time. Aluminum processing is easy and clean. No matter the machine tool or the user's hands will not be stained with sand from the sand mold

aluminum has the required strength, but it is not hard enough to crack easily. The surface of aluminum can be sprayed, so it can be designed in modern industry. For applications in special environments, such as the pharmaceutical industry, the shell can be made of stainless steel

nowadays, a lot of work is done by vibrators. Her main applications are emptying hopper, material screening, concrete tamping and feeding of sand, soil and any other powder or small particles and screws. Vibration is also used to detect the contact of printed circuit board in the electronic industry

1.1.1 vibrator classification

according to the form and working principle of energy consumption of vibrators, vibrators can be generally divided into the following types:

energy form technical form electric rotation/linear/magnetic

pneumatic rotation/linear

hydraulic rotation

1.2 about pneumatic vibrators

1.2.1 what work is vibration suitable for

as mentioned above, with the help of vibration force, any type of bulk material can be fed, tamped or sorted. In most cases, vibration has a "supporting" effect on gravity. For example, due to the influence of moisture, the bulk materials may adhere to each other in the hopper, blocking the hopper. In this case, the vibration can disperse it, so the material flows out of the hopper under the action of gravity

gravity and vibration

another application of vibrators is in concrete. Vibrate the concrete, that is, vibrate the sand and stones to make them reach the most dense state, and remove the intermediate bubbles from reducing noise, vibration and irregularity (NVH). In the process of tamping, it mainly depends on gravity, but vibration will help this and greatly improve its effect

in both cases, vibration will reduce the friction of the material

vibration does not necessarily support gravity. Sometimes vibration will make the material "jump", and gravity will make the material return to the material path. With the help of the linear vibrator, we can give the jumping direction of the material, and the step length of the jumping can be changed by adjusting the amplitude

material feeding

1 2 . 2 basic information

when selecting any type of vibrator, there is a very important thing to know: Although you can calculate the natural frequency of materials, silos, silos, etc., in practical application, the result will never get the same value as the calculation

we can use tables and calculation formulas to correctly select the force, frequency and installation position of the vibrator, but "fine adjustment", that is, the optimal adjustment of the vibrator, is the problem of test adjustment in practice. Experienced field engineers can quickly select the best vibrator type and installation position

rules of thumb and tables are given in the section "selecting the best vibrator type"

in order to realize the best adjustment of the vibrator, it is suggested to add pressure regulating plastic granulator into the air circuit. The industry should constantly improve the technical level of valve or needle valve to achieve the purpose of controlling air flow and pressure. Finding out the natural frequency of materials to be fed, tamped or sorted is the best way to adjust the vibrator

the working frequency range of the pneumatic external vibrator is from 2000rpm to about 20000rpm or about 35-350hz. The data given in the technical parameter table is obtained under the following conditions: the vibrator is placed on the fixed test bench, and the vibrator is in a non actual working state, that is, the amplitude is zero, but the frequency is 2-3 times higher than that when it is actually installed on the workpiece

generally, the natural frequency of the material will be higher than that of the vibrator, so a stronger vibrator should be used to do a certain work

do not let the vibrator work at full load. When using a new vibrator, it is recommended to make it work under 3/4 full load. Therefore, when its power is reduced due to wear and aging, it can be appropriately compensated by increasing the frequency

note: the working pressure of pneumatic rotary and linear vibrators cannot be higher than 7bar (100psi)

2. The air consumption of pneumatic system

2.1 and the air consumption of air compressor

vibrator system, especially the average air consumption, are the basis for calculating the required compressor size

2.1.1 calculate the average air consumption

Formula 1. Air consumption: cons = XXX L/min

2. Working coefficient (on/off) * 100%:opf = xxx%

3. Average air consumption = cons * opf

that is, ACON = XXX L/min

4 Total average gas consumption = XXX liters/minute

to obtain the total average gas consumption of several vibrators and/or other gas consuming components on the same gas path, if the gas consumption of each component is the same, multiply the average gas consumption by the number of components; If the air consumption of each component is different, multiply them respectively and add the results

when determining the size of the required air compressor, it is recommended to add 20% safety margin to the above calculation results, because the given values in the table may also change. In addition, leakage or additional components will require a larger air compressor. Additional components installed in the future may require more energy

another data is also necessary to determine the size of the air compressor, which is the maximum air consumption within a given time. This data can be determined by the air consumption of all components working at the same time and the length of their working time

maximum air consumption = number of components * cons (within XX minutes)

= XXX liters/minute (within XX minutes)

both the maximum air consumption and the average air consumption are useful in determining the size of the air compressor

2.2 lubrication

is lubrication required? This is a very important issue. In general, lubrication always prolongs the life of components, because it can greatly reduce friction. However, lubricating the ball vibrator is a waste of lubricant, because it can not significantly increase the service life of the vibrator, and the T series runner vibrator will be quickly damaged without lubrication

due to special materials and treatment methods (fluorine coating, etc.), the working friction can be minimized, so the piston vibrator (FP Series) Dar series vibrator also has good emergency working characteristics. Nevertheless, add lubricating oil after the work to prevent the wear from intensifying

it can't be generalized to add a few drops of oil per minute or not more. Reciprocating or piston air compressors can provide enough lubricating oil with air, so there is no need to add lubricating oil. Unfortunately, the same type of compressor will also bring too much oil due to excessive leakage, which will cause the frequency and force of DAR series vibrator to drop due to adhesion. In addition, for compressors with built-in air dryers, air path oil atomizers are required to prevent premature wear of T-series Dar series and FP series vibrators

note: please use the following viscosity lubricating oil to lubricate findeva vibrator

isovg5 viscosity 5cst/40 ℃ (5 centistokes or about 42.4 or 5cm2sec2)

the lubricating oil used should be non adhesive, as shown below:

shell Dulux c5

Esso nutoh5

Mobil velociteno 4


for applications in the food industry, whelerex304 (plant-based)

note: if the viscosity of the oil does not match the recommended value, the frequency and force will be reduced

for FP series vibrators, distilled water can be used as lubricant, and its effect is the same as that of lubricating oil. When using, adjust the dosage to 10 drops/minute

as a gas path oiler, the effect of oil dripping lubricator is stronger than that of wick oiler. Check the oil stain at the silencer and adjust the lubricator to minimize the oil stain, but it does not completely disappear. Too much lubricating oil will cause the piston or roller to stick, so it should be avoided

2.3 air filter and pressure reducing valve

all air compressors are equipped with air filters to protect the valves of the air compressor. In this way, the air given by the air compressor is enough for the rotary vibrator. Since small dust particles may be brought in, we strongly recommend using 5 on the gas path μ M or less, which helps to prolong the service life of the vibrator

note: since the clearance between piston and air in FP series is very small, we strongly recommend using 5 μ M air filter

the air filter should be installed close to the vibrator to prevent rust particles on the metal gas pipe from entering the vibrator. It is recommended to connect the filter, pressure reducing valve and lubricator as shown below

correct installation sequence: filter, then pressure reducing valve and oil mist

2.4 air pipeline

the vibrator can be adjusted by increasing or decreasing air pressure or flow, but the size of inlet pipe and exhaust pipe should also be appropriate. If this ratio is too small, the vibrator will not work at full power

the exhaust pipe should be as short as possible, because the discharged gas will expand, which is several times the differential pressure

the formula is: V in * P in = V out * P out

here P is the absolute pressure. Therefore, it can be easily seen that when the vibrator works at 6bar (relative pressure), the gas volume at the exhaust end will be 6 times that at the inlet end

too long or too short exhaust pipe will affect the movement of air, that is, not all air pressure can be converted into vibration energy of vibrator

it is the best way to obtain the maximum vibration energy by using a silencer directly installed on the vibrator

example: the air consumption at 4bar is 900 L/min, and the length of the tube is 10 meters. Start at 900 on the right and go left to the line of 4bar, and go up along the 45 ° line to the end boundary line of the segment. Then, follow the straight line to the left until the 10m line, and then follow the 45 ° line to the right until the maximum allowable pressure loss line of the system. At this time, the diameter and area of the pipe are on the left

note: the pressure loss in the pipeline should not be greater than 0.5bar; However, it is meaningless to reduce this value very small, because it will increase the diameter and cost of the pipe. The ideal value is 01. Technical specifications for longitudinal load (tension) test 1—0.5bar

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