1. Precision second-class standard (absolute error 0.8Pa)
2, working environment temperature 20 + 5 * C, humidity does not exceed 80 %
(1) Place the micro-pressure gauge on a flat workbench, then adjust the adjustment screw to make the instrument level (observation
The bubble of the level bubble is in the middle of the black circle)
(2) After adjusting the fine adjustment dial and the indicator block to “0” point, connect the dynamic pressure nozzle with a hose and pour distilled water.
Observe that the level head is close to the liquid surface from the mirror, stop adding water, then screw the top seal screw to tighten, then slowly adjust the fine adjustment disc to make the rise and fall several times, so as to eliminate the air in the connecting tube. After that, adjust the dynamic pressure tube adjustment nut so that the liquid level and the needle tip are completely tangent (it can be stable after 3 to 5 minutes).
4. When using as a working instrument:
(1) The pressure should be connected with the pressure gauge of the micro pressure gauge and the rubber tube (to ensure good air tightness)
Move the dial slightly, dial the corresponding value on the dial and dial the value after the decimal point on the fine dial. The sum of the two numbers is the meter reading mmH2O.
(2) When measuring the negative pressure, connect the negative pressure nozzle to the static pressure nozzle of the micro pressure gauge with the rubber conduit, and press the same item as above.
The method reads the indication value and calculates it, which is the measured negative pressure.
(3) The measured pressure difference should be connected with the rubber pipe of the positive and negative pressure nozzles and the corresponding pressure gauge of the micro pressure gauge.
The same method reads the difference between the indications and performs the calculation, that is, the measured pressure difference,
Special attention: the density of water at different temperatures is different, there is a comparison table to give the corresponding pressure values of 25 degrees and 15 degrees
5. Maintenance and precautions:
(1) The micro-pressure gauge should be kept clean at all times. After use, it should be cleaned and covered, and the plastic cover should be covered to prevent rash.
Dust entering the liquid surface affects the tangential point of the liquid surface and the tip of the needle, causing reading errors.
(2) When removing mirror dust, wipe it with a soft flannel that does not damage the mirror surface.
(3) When the instrument is used for sealing inspection, it must not exceed the pressure of the upper limit of measurement, otherwise, the instrument will be stuck.
(4) When the rotary fine adjustment dial is almost at the top or bottom, it should not be rotated hard, otherwise, the card of the instrument will be caused.
The rolling phenomenon affects the accuracy of the instrument.
(5) There should be no vibration during use. Although it is a slight vibration, it can also cause fluctuations in the liquid surface, display reading.
(6) Under normal use, it is not allowed to rotate the fastening screws of each connecting part to prevent air leakage.
(7) When using the micro-pressure gauge, the distilled water should be replaced in about 2 months. When it is not used for a long time, the distilled water should be discharged, wiped clean, and covered with a plastic sleeve.