What are the measuring devices of the air duct cleaning device?
1. General requirement of the air duct cleaning device
The determination instruments shall be calibrated or corrected according to the relevant standards or specifications.
2. Determination of air flow of the air duct cleaning device
The air flow determination device usually adopts the devices of connecting the standard orifice plate or the standard nozzle etc. with the micro-pressure gauge. The throttling device may be designed and mounted according to GB 2624.1 and GB/T 1236. The division value of the micro-pressure gauge shall not be more than 2Pa ~ 5 Pa. The micro-pressure gauge with low division value is used at small air flow, and the micro-pressure gauge with the high division value is used at large air flow.
3. Determination of resistance of the air duct cleaning device
Connect the static pressure rings on the pipe to the micro-pressure gauge through the hose for determination. The division value of the micro-pressure gauge shall not be more than 2 Pa.
4. Determination of one-time efficiency of the air duct cleaning device
Connect the sampling pipes 5 and 6 at the upwind and downwind sides to two air samplers through the hoses for determination.
The connections of sampling pipes, connecting hoses and air samplers shall meet the following requirements:
a) Sampling pipes
The sampling pipes are the pipes with smooth and clean inner walls and are made of stainless steel or Teflon. For the diameter selection of the sampling pipe orifice, the approximate isokinetic flow condition shall be considered, namely, the suction speed of the sampling pipe orifice shall be approximate to the air speed in the air duct cleaning device, and the maximum deviation shall be less than ±10%.
b) Connecting hoses
The connecting hose for connecting the sampling pipe with the air sampler shall be a clean joint-less hose. The connecting hose shall be as short as possible, its length is not be more than 1.5 m, and the length of the horizontal section is generally not more than 0.5m;
c) Air samplers
The chemical pollutants are generally sampled with the constant flow air sampler which has the sampling range of 0.1 ~ 10 L/min and is continuously adjustable. The biological pollutants are generally sampled with the impact type air microbe sampler (with the capture rate higher than 95%) which has the sampling flow of 28.3 L/min and the adjustable accuracy lower than 5%.
