Cangzhou Xinglong Engineering Instrument Co

Type LCD Digital Display Breathing Air Permeability Specific Surface Area Tester Wholesale Price for Breathing Air Permeability Ratio Testing
Type LCD Digital Display Breathing Air Permeability Specific Surface Area Meter is mainly based on the relevant provisions of the national standard "Method for Determination of Cement Specific Surface Area" and refers to Made by improving the American breathability method. The basic principle is to measure the difference in resistance experienced when a certain amount of air passes through a compacted powder layer with a certain void ratio and a certain thickness. It is mainly used to determine the specific surface area of cement and can also be used to determine the specific surface area of ceramic abrasives, metals, coal, food, gunpowder and other powdery materials.
[Technical indicators]
Use high-reliability microcontrollers and integrated circuits to automatically adapt to different temperatures and automatically detect the working status of the instrument to ensure accurate and reliable measurement results.
Automatic detection of water level, automatic timing, automatic temperature measurement, automatic calculation and display of results.
Except for manual loading, the entire test process is completed automatically to avoid human errors.
It is very simple to press one measurement button to output a measurement result.
The scope of use applies to the specified range.
Relative error of measurement accuracy﹤
Degree ℃
Pressure
Air cylinder inner cavity diameter
Air cylinder inner cavity sample height
Number of orifice plate holes
Orifice plate aperture
Orifice plate thickness
Packing size
Weight/net weight
[Usage method and operating steps] Please refer to the cement specific surface area measurement method for the usage method and operating steps. The relevant provisions of the Bertrand method are excerpted as follows
Calibration of the instrument
Use standard materials with specific surface areas close to / and / to calibrate the test instrument. Standard samples should be kept at room temperature before use.
Determination of the volume of the sample layer
Determine the volume of the sample layer using the following mercury displacement method
Put the two pieces of filter paper into the breathable cylinder along the cylinder wall and use a push rod (Appendix 1) ), press the big end down until the filter paper is placed flatly on the perforated plate, and then fill it with mercury. Use a thin glass plate to lightly press the mercury surface so that the mercury surface is flush with the top of the cylinder. Pour the mercury from the cylinder, weigh it, and record the mass of the mercury. .
Take out a piece of filter paper from the cylinder, add an appropriate amount of powder, cover it with a layer of filter paper, and compact it with a tamper until the supporting ring of the tamper contacts the top edge of the cylinder. Take out the tamper and add it to the upper space of the cylinder. For mercury, use the above method to make the mercury surface flush with the top of the cylinder, then pour out the mercury, weigh it, and record the mass of the mercury. (Weighing is accurate to
The volume occupied by the sample layer is calculated by the following formula (accurate to
/mercury
The volume of the sample layer in the formula
is filled when the cylinder is not filled with material. The mass of mercury in the cylinder
The mass of mercury that fills the cylinder after the cylinder is filled with materials
The density of mercury at the mercury test temperature (see Table 1)
The volume of the sample layer is measured at least twice Each time it should be compacted separately, the average value of the two values with no more than the difference should be taken and the temperature near the cylinder during the measurement process should be recorded. The volume of the sample layer should be recalibrated every one quarter to half a year.
Note A solid sample should be prepared. If the cement layer is too loose or the cement layer cannot reach the required volume, the trial amount of cement should be adjusted.
Air leakage inspection
Plug the top of the breathable cylinder with a rubber stopper and connect it to the pressure gauge. Use a suction pump to extract part of the gas from one arm of the pressure gauge and then close the valve. If there is any continuous drop in the liquid level in the pressure gauge, it indicates air leakage in the system and needs to be sealed with piston grease.
Sample preparation
After drying and cooling to room temperature at ℃, pour the standard sample into a sealed bottle and shake vigorously to break up the agglomerated sample to loosen the sample. After letting it stand, open the bottle cap and stir gently to allow it to settle during the loosening process. The fine powder reaching the surface is distributed throughout the sample.
The cement sample should first pass through a square hole sieve and then be dried at ℃ and cooled to room temperature.
Determine the standard test used for the sample amount calibration test The weight of the sample and the weight of the cement to be measured should reach the void ratio in the prepared sample layer. The calculation formula is:
The required sample amount in the formula
Sample density
The sample layer measured as above Volume
Porosity of the sample layer (Note).
Table 1 Mercury density and air viscosity at different temperatures
Note Porosity refers to the volume of the pores in the sample layer and the total volume of the sample layer. The volume ratio of general cement is used. If the sample amount calculated according to the above formula cannot be accommodated in the effective volume of the cylinder or cannot fill the effective volume of the cylinder after tamping, the void ratio is allowed to be appropriately changed. < br/> Preparation of sample layer
Place the perforated plate into the flange of the breathable cylinder with the marked side facing down. Use a push rod to push a piece of filter paper (see note) to the edge of the perforated plate and press it tightly. Weigh. Take the exact amount of cement determined in the previous section and put it into the cylinder. Tap the edge of the cylinder gently to make the surface of the cement layer flat. Then put in a piece of filter paper and use a tamper to evenly tamp the sample until the support ring of the tamper tightly touches the top edge of the cylinder and rotates. Slowly take out the tamper to prepare the sample after two weeks. The breathable cylinder should be inserted into the cylinder holder for operation.
Note: The filter paper on the perforated plate should be a disc with the same inner diameter as the cylinder and a smooth edge. Each measurement requires The new filter paper uses medium-speed quantitative filter paper.
Air permeability test
Connect the air-permeable cylinder containing the sample layer to the pressure gauge to ensure that the connection is tight and air-proof (note that it cannot be vibrated any more. The sample layer.
First close the cock on the arm of the manometer and start the air pump (Note: slowly open the cock and steadily extract air from one arm of the tube manometer until the liquid level rises to the top mark. Close the cock and air pump. Start timing when the concave surface of the liquid in the pressure gauge reaches the second engraved line. Stop timing when the concave lunar surface of the liquid reaches the third engraved line. Record the number of seconds when the liquid passes the second and third engraved lines and write it down. Test temperature (℃)
Note: To avoid air leakage, apply a thin layer of piston grease on the lower conical surface of the cylinder and then insert it into the conical grinding opening at the top of the pressure gauge and rotate it for two weeks.
Note: The negative pressure of the air pump can adjust the tightness of the pipe clamp on the rubber pipe. The pipe clamp should be removed and placed in the accessory box to protect the rubber pipe.
[Calculation]
When the density of the material to be tested is the same as the void ratio in the sample layer and the standard sample, the temperature difference during the test can be calculated by the following formula
If the temperature difference during the test is greater than ℃ When the test sample is tested, it is calculated according to the following formula
The specific surface area of the tested sample in the formula
The specific surface area of the standard sample
The time measured by the drop of the liquid level in the pressure gauge during the test of the tested sample
The time measured when the liquid level in the pressure gauge dropped when the standard sample was tested
The air viscosity of the tested sample at the experimental temperature ( )
The air viscosity of the standard sample at the experimental temperature ( )
If the porosity in the sample layer of the tested sample is different from the porosity in the sample layer of the standard sample, the temperature difference during the test can be calculated according to the following formula
If the temperature difference between the two during the test is greater than ℃, press Calculate by the following formula
In the formula, the void ratio of the tested sample
The void ratio of the standard sample
If the density and void ratio of the tested sample are different from those of the standard sample, the temperature difference during the test can be ℃. Calculate according to the following formula
If the temperature difference between the two tests is greater than ℃, use the following formula to calculate the density of the tested sample in the formula
Density of the standard sample
The cement specific surface area should be calculated twice The average value of the test results is determined. If the difference between the two test results exceeds the average value, the test should be retested. Calculations should be accurate to the following values subject to rounding.
The specific surface area value calculated in / units needs to be multiplied by a coefficient to convert the specific surface area value in / units
[Maintenance and care]
The instrument should be wiped frequently to keep it clean and loaded when not in use. inside the box.
The liquid level in the barometer body should be maintained at the specified height.
After the test is completed, clean the cylinder and perforated plate and put them into the accessory box for later use.
Before the test, attention should be paid to check whether the electromagnetic pump is operating normally. The negative pressure should be adjusted in advance to prevent liquid from being accidentally sucked into the electromagnetic pump. (During the test, if you find that the liquid level cannot rise to the top line or the liquid level rises too fast and reaches the middle of the glass tube and ball, the pump and valve still do not stop. You can press the confirmation button to stop the test immediately. Open the back cover of the chassis and adjust the belt. Connect the throttle valve to adjust the negative pressure change rate).
When using the instrument, avoid direct exposure of strong light to the photocell or situations where the light brightness changes frequently.
[Accessories]
One accessory box
One spoon
One pair of tweezers
One brush
Two rubber plugs
Round One cylinder holder
One push rod
One breathable plate
One breathable cylinder
One pounder
One bag of filter paper