The function and classification of the atmospheric sampler

Atmospheric samplers are instruments or devices that collect atmospheric pollutants or contaminated air. There are many kinds of them, and they can be divided into gas sampler and particle sampler according to the object of collection; they can be divided into environmental sampler, indoor sampler and pollution source sampler according to the use place. In addition, there are special-purpose atmospheric samplers, such as samplers that simultaneously collect gas and particulate matter. The gas sampler is generally composed of three parts: a collector, a flow meter, and a pumping power system.

The atmospheric sampler plays a very good role in the detection of air and harmful gases in the environment. With the continuous advancement of science and technology, the atmospheric sampler is also constantly introducing new products, such as: intelligent atmospheric sampler, explosion-proof atmospheric sampler, dual-channel atmospheric sampler, and other products, which greatly enriches the classification of atmospheric samplers.

As more and more attention is paid to environmental issues in the country, there are more and more companies that produce products using environmental samplers and other environmental protection instruments. It is precisely because these entrepreneur-led research teams continue to develop research that makes today's atmospheric sampler more accurate and more complete. Such as: Skyray Instrument, Xinbao Technology and so on.

The atmospheric sampler is just a part of the sampling instrument, as well as individual samplers, dust samplers, dust samplers, and explosion proof samplers.

The gas sampler generally consists of three parts: a collector, a flow meter, and a pumping power system.

Collectors: There are generally the following types: 1 Absorption tubes: Bubble absorbers and porous glass absorbers are used to absorb gaseous or vaporous contaminants. The latter can also collect aerosol aerosols, such as sprayed agrochemical emulsions. Impact absorbers are mainly used to collect soot and particulates. 2 filter sample clamp: used to collect smoke and particulate matter. Filters are made of inorganic materials such as glass fiber membranes and quartz filters; organic compounds such as acetic acid or nitrocellulose membranes, fluororesin membranes, polytetrafluoroethylene membranes, and nylon membranes are also available. More recently, organic membranes, which are used to hit nuclear bodies with a certain size, have also been used. They are also known as nuclear pore membranes. 3 Solid particle sampling tube: The tube can be filled with silica gel, ceramic fragments or other solid particles for the collection of gaseous or aerosol pollutants. 4Gas extraction pipes, syringes, and vacuum bottles are used to collect small amounts of gaseous pollutants. The collector that collects the sample in the flue gas generally uses the probe to extend into the flue. The structure is slightly different from the above sample clamp, but its function is similar.

Flowmeters: Airflow is usually measured with orifices or rotameters. Automatic flow control components can also be fitted to ensure stable air flow during sampling.

Pumping power system: It is actually a vacuum pumping system. Usually electric vacuum pumps, scraper pumps, membrane pumps, electromagnetic pumps or other suction pumps. The electric vacuum pump has a large amount of air extraction and can be configured on a large flow sampler. Scraper pumps, membrane pumps, and electromagnetic pumps draw less gas, but they are lighter and easier to carry and can be configured on small flow samplers.

Particulate matter sampler is commonly used in the filtration method and can be roughly divided into two categories:

Universal particle sampler: Collects particles in a range of particle sizes. This type of sampler is divided into large flow rate samplers (usually 1.1 to 1.7 meters per minute) and small flow samplers (less than 20 liters per minute) depending on the volume of the extracted gas. The particle size of the particles collected by the large flow sampler (Fig. 1) can be as large as 40 to 60 μm, and the influence of wind speed and direction is more significant when sampling.

Granularity graded samplers: There are two main types. One is a multi-layer orifice plate impact graded sampler. Particles enter the sampler along with the gas flow. Through the orifices with different pore sizes, particles of various particle sizes are separated and left on the membranes of each layer. Currently designed impact graded samplers generally collect particulate matter with a particle size of less than 15 microns and grades of grades below 10 grades. Such as Anderson multi-stage impact sampler, there are 6 to 10 various types (Figure 2). It is also possible to install a particle size separator (slit-type or round-hole type metal plate) on the collector of the above-mentioned large flow sampler, that is, a large flow impact typed sampler. The other is a double-separation sampler (Fig. 3), which uses the inertia of particles in the gas flow. Particulate matter with a particle size of less than 15 μm is divided into two parts, larger and smaller than 3.5 μm, into two channels and collected in the filter. On the membrane. The particle sampler also has various types such as a strip filter sampler and a timed continuous filter sampler.