Standards: GB 8074 and ASTM C204
Model: DBT-127, FBT-5
1. Calibration of instrument
Should calibrate the instrument before operation. Use standard material with specific surface area of 2800cm2/g and 4000cm2/g to calibrate the instrument, the standard sample temperature should be consistent to the room temperature before using.
2. Material layer volume test
Use Mercury displacement method to test the test sample layer volume.
Step 1: place 2pcs filter paper into the permeability cylinder (along the inwall to place), use push rod big end to press down till the filter paper is placed horizontally on the perforated plate, then fill full with mercury, use a thin glass plate to slightly press on the mercury surface, let the mercury surface to align with the cylinder upper open, then pour out the mercury and weigh it, record the mercury weight P1.
Step 2: Take out 1pc filter paper from the cylinder, then fill in proper quantity powder material, then cover with another filter paper and use tamper to compact till the tamper supporting ring contact with the cylinder top edge, take out the tamper, then again fill in mercury at the top of cylinder till align to the cylinder upper open, then again pour out the mercury and weigh it, record the mercury weight P2 (accurate to 0.5g).
3. Sample preparation
3.1. Dry the standard sample under 110℃±5℃ and cool to room temperature, pour into the 100ml sealed flask and swing by 2mins to break the sample, and place it by 2mins, then open the cap and stir it lightly, let the surface fine powder distribute to the whole sample;
3.2. The cement sample should firstly go through the square hole sieve of 0.9mm mesh, then dry it under 110℃±5℃ and cool to room temperature.
3.3. Confirm the sample weight: calibrate the standard sample weight and test cement sample weight, the test sample layer void ratio should reach to 0.500±0.005, the formula is as below:
W--- The sample weight (g)
ρ--- Sample density(g/cm3)
V--- Sample layer volume (cm3)
ε---Sample layer void ratio(cement for 0.5)
4. Test sample layer preparation
Place the perforated plate on the permeability cylinder Flange, let the marked surface downward, use push rod to place a filter paper to the perforated plate with edge pressed. Weigh the cement sample accurate to 0.0001g and pour into the cylinder, slightly knock cylinder to let cement surface flat, then place another filter paper and use tamper to tamp the material till the tamper supporting ring tightly contact the cylinder top edge, rotate two cycles, take out the tamper slowly, when make sample should place the permeability cylinder plugged on the cylinder holder.
5. Air permeability test
5.1 Connect the cylinder filled with sample to the pressure gauge, should guarantee tight connection and no leakage, and can’t shake the sample any more
5.2 Firstly turn off the stopper on the pressure meter, start the air pump, slowly turn on the stopper and extract air smoothly from one arm of the U tube pressure meter, till the liquid level up to the top scalemark then turn off the stopper and air pump. When the liquid concave surface reach the second scalemark then start timing, when the concave surface reach the third scalemark then stop timing, record the time to pass the second and third scalemark and record the test temperature.
1. To avoid air leakage, can coat oil grease at the cylinder lower cone side, then plug it into the top mouth of the pressure meter and rotate by two circles.
2. The negative pressure degree can be adjusted through adjusting the tightness of the tube clamper, the tube clamper should be uninstalled and placed in the accessory box.
1. Keep the instrument always clean and store up properly
2. The liquid of air pressure meter should maintain a specific height
3. Clean the cylinder and perforated plate after test and storage properly
4. Check the Electromagnetic pump before testing, the negative pressure should be adjusted in advance, avoid to suck into the pump;
5. During the test if found the liquid level can’t rise to the top scale mark, or the liquid level was rise too fast (rise to glass tube ball pump and valve still not stop). Under this condition can press “Enter” to stop test immediately, and can open the back cover to adjust the Throttle to adjust the negative pressure changing rate.
6. Do not use the instrument under intensive sunlight condition or frequently changed light brightness occasion.
7. Structure schematic
DBT-127 Electric Blaine air permeability apparatus structure schematic
1. Base 2. Water level scale 3. Timing final scale 4. Timing start scale
5. First scale 6. Rotary stopper 7. Pressure meter
8. Air permeability cylinder 9. Perforated plate 10. Tamper
11. Extraction pump 12. Indicator 13. Switch
FBT-5 Digital display Blaine air permeability apparatus structure schematic
1. Air pump 2, Throttle with joint 3. Electromagnetic valve 4. Control cabinet 5. Temperature sensor
6. Air pressure meter 7. Water level scale 8. Timing final scale 9. Photoelectrical switch 10. Timing start scale 11. First scale 12. Pressing plate 13. Rubber tube 14. Perforated plate 15. Tamper 16. Air permeability cylinver