The formaldehyde gas detector tube
Technical field
The utility model relates to the simple and easy harmful gas pick-up unit of a kind of suitable family self check, in particular for measuring the formaldehyde gas detector tube and the detection method thereof of content of formaldehyde in the air.
Background technology
The most of material that is used to decorate is as wood-based plate, polyfoam, wallpaper wall paper, carpet floor, paint etc., directly or indirectly release formaldehyde; Many daily necessitiess as various pesticides, detersive, cosmetics, part household electrical appliance and furniture etc., also can be emitted formaldehyde; A lot of life waste gas as food spoilage waste gas, culinary art smog, cigarette combustion gas, vehicle exhaust etc., also contain formaldehyde; This makes formaldehyde become especially one of the major pollutants of indoor environment of the modern life.Studies show that air formaldehyde concentration is 0.2mg/m
3Shi Huiyou peculiar smell and sense of discomfort, 1mg/m
3The time eyes and nose have excitement, 5mg/m
3The time can cause shed tears, feel sick, symptom such as cough, uncomfortable in chest and asthma, concentration high energy more directly causes nasal cavity, oral cavity, throat, skin and gastral pathology.For this reason, many countries have all made guiding limit value regulation to airborne concentration of formaldehyde, and the concentration of regulation formaldehyde in indoor air should not surpass 0.1mg/m in " the IAQ (indoor air quality) standard " of China's issue on March 1st, 2003
3
The method of measuring formaldehyde is a lot, and present main means are the sample of collection in worksite to be taken back the laboratory handle, and finish analytical test by professional equipments such as spectrophotometer, chromatograph, electrochemical analyser, chemiluminescent analyzers.Though these class methods are measured accurately, need analytical instrument and certain professional knowledge and means, be difficult for popularizing and on-the-spot the realization.
In order to satisfy the needs of on-line testing, some on-the-spot small-sized formaldehyde analysers that use have also appearred on the market, as the PPM400 type formaldehyde determination instrument of Britain PPM company production and 4160 type formaldehyde determination instrument of American I NTERSCAN company production is to design according to electrochemical principle, utilizes the on-the-spot formaldehyde determination instrument of portable 101 types of phenol reagent process principle making etc. in addition.These instruments cost an arm and a leg, and Sensitive Apparatus is short serviceable life, all is not suitable for simple and easy monitoring and uses.
Chinese patent discloses several simple detection design proposals.99117400.3 announced a kind of " being used to detect test paper, test solution and the detection method thereof of formaldehyde, methanol content ", the method sensitivity is lower, change color is not obvious, is not suitable for the mensuration of low concentration formaldehyde; 03140531.2 announced a kind of " being used for detecting the polymeric adsorbent and the detection method thereof of room air content of formaldehyde ", it utilizes the ammonium salt solution of formaldehyde and diacetone to generate faint yellow compound under certain condition and measures formaldehyde, the change color of this method is not obvious, temperature influence is very big, and these factors all can cause very big error; 02285930.6 announced a kind of " in the disposable air formaldehyde colorimetric speed survey bag ", it utilizes the method for diacetone or phenol reagent to measure formaldehyde, also has problems such as the not obvious and temperature effect of change color is bigger.
Summary of the invention
The purpose of this utility model is the deficiency that overcomes conventional art, and the self check of a kind of suitable family, cheap, easy to use, highly sensitive, formaldehyde gas detector tube that phenomenon significantly is used for measuring the air content of formaldehyde are provided.
For achieving the above object, the utility model goes out a kind of simple gas detector tube of measuring content of formaldehyde in the air according to the principle design that chromogenic reaction generation brown material takes place for benzene series thing and formaldehyde under the acidic catalyst effect.As container, the colour developing potpourri is loaded in inside to this detector tube by transparent glass outer tube, and two ends are stopped up with polyvinyl chloride fibre, acrylic fibers or glass fibre and sealed with end socket.The internal diameter that it is characterized in that the glass outer tube is 1.5~3.5mm; Inner colour developing potpourri is made of carrier and the colored indicator that adheres on it, carrier can be colourless or white inert substance, as silica sand, the unglazed pottery powder, silica white etc., the carrier granularity is 80~100 orders, colored indicator is the potpourri of benzene series thing and acidic catalyst, the benzene series thing can be a benzene, toluene, ethylbenzene, dimethylbenzene or diethylbenzene, it also can be potpourris several in them, acidic catalyst can be a sulfuric acid, mineral acid such as nitric acid or phosphoric acid or iron sulfate, cerous sulfate, acidic materials such as aluminium oxide or zirconia, the consumption of benzene series thing and acidic catalyst are respectively 10~30% and 5~25% of vehicle weight.
This gas detecting tube can take dual mode to demarcate and use, and the one, connect constant flow pump and allow the tested gas detector tube of at the uniform velocity flowing through, the 2nd, place naturally and allow tested gas be diffused into carrier surface naturally; The former can fast measuring goes out the result but needs equipment such as constant flow pump, and the latter uses simple but minute is longer.
When containing formaldehyde in the tested gas, formaldehyde reacts with the colored indicator that touches at first rapidly and generates stable brownish red material, the formaldehyde that enters detector tube subsequently then can continue to react with the indicator of not colour developing, enter the increase of the amount of detector tube along with formaldehyde, detector tube will and constantly extend to the other end since an end by colourless or whitely become brownly.Variable color length and gas flow or the natural content that can measure formaldehyde in the air diffusion time according to detector tube.
The utlity model has following evident characteristic:
1, can produce the gas detecting tube that is suitable for measuring different content of formaldehyde according to the consumption and the different of glass tube internal diameter of colored indicator;
2, the filling of the interior colour developing of detector tube potpourri should take into account the unobstructed mobile of gas molecule and fully contact;
3, change color is from colourless or white vision is obvious to brown, boundary clear.
Description of drawings
Fig. 1 is the structural representation of formaldehyde gas detector tube.
Each assembly is among the figure: 1 end socket, 2 filtering layers, 3 colour developing potpourris, 4 glass tubes, 5 scale marks.
Embodiment
The utility model can be made the different formaldehyde gas detector tubes that are fit to multiple occasion according to the difference of glass tube internal diameter, benzene series thing, catalyzer, carrier or colour developing mixture ratio.Only selecting wherein at this, two embodiment narrate.
Embodiment 1:
With the glass tube of internal diameter 2mm fully wash, drying, it is long standby to be cut into 10cm.Take by weighing 10 grams, 80~100 purpose silica whites, be placed in the clean conical flask through washing, drying, cooling, the cerous sulfates that take by weighing 1.5 gram porphyrizes add and wherein to mix, and other takes by weighing 2 gram dimethylbenzene and adds wherein, mix the back in 70 ℃ of dryings 20 minutes, be placed to room temperature, in its glass tube of packing into, two ends glass fibre shutoff, calibrate, the cover upper cover is promptly made gas detecting tube.
This detector tube is applicable to that measuring content of formaldehyde is 0.05~0.20mg/m
3Gas, error at measurment is in 10%.
Embodiment 2:
With the glass tube of internal diameter 1.8mm fully wash, drying, it is long standby to be cut into 10cm.Take by weighing 10 grams, 80~100 purpose unglazed pottery powder, be placed in the clean conical flask, at first add the 1.3 gram concentrated sulphuric acids through washing, drying, cooling, mixed evenly back was in 110 ℃ of dryings 10 minutes, be placed to room temperature, add 1.8 gram dimethylbenzene then, mix the back in 70 ℃ of dryings 15 minutes, be placed to room temperature, in its glass tube of packing into, two ends glass fibre shutoff, calibrate, the cover upper cover is promptly made gas detecting tube.
This detector tube is applicable to that measuring content of formaldehyde is 0.01~0.10mg/m
3Gas, error at measurment is in 10%.