Constant current gas sampling assembly and method
Technical field
The present invention relates to the gas sampler field, relate in particular to a kind of constant current gas sampling assembly and method.
Background technology
The cardinal principle of air sampler is with the sampling pump draw samples, adopts the different steady flow measures and the method for time synchronisation, reaches gaseous state or steam sample in the quantitative collection atmosphere, for use in the objectionable constituent of analyzing wherein.Existing air sampler during mainly by membrane pump, variable valve, impact damper, flowmeter, electronics control circuit, under-voltage indicating circuit and power supply etc. partly form.The weak point that existing air sampler exists is mainly: 1, the used material of the membrane pump of sampling thief or flow regulator can produce distortion when temperature variation, causes the variation of flow; 2, gas flow is difficult to automatic adjusting, needs manual operation to regulate flow, and error is bigger; 3, membrane pump, surge flask and temperature control equipment cause that sampling thief costs an arm and a leg, volume is big, be not easy to carry, 4, to cause gas flow pattern be one one in the use of membrane pump, but not continuous flow finally causes under total time integral, and total flow is inaccurate; 5, the noise that causes of membrane pump is big.
Summary of the invention
(1) technical matters that will solve
The technical problem to be solved in the present invention provides a kind of constant current gas sampling assembly and method, makes the gas can continuous flow, and can regulate flow fast and effectively automatically, remains the flow that just pre-sets before the startup.And reduce volume, reduce cost, reduce noise.
(2) technical scheme
For solving the problems of the technologies described above, the present invention proposes a kind of constant current gas sampling assembly, comprising:
Stack shell, has the stack shell space in it, be provided with the gas flow sensor that has gas flow sensor air intake opening and gas flow sensor gas outlet in the described stack shell space, the front end of described stack shell is provided with the valve that makes described gas flow sensor air intake opening and described stack shell external communications
Cavity, it comprises cavity antetheca, cavity wall and cavity rear wall, described cavity antetheca is provided with cavity antetheca pore, make the internal communication of described gas flow sensor gas outlet and described cavity, the forward part in the inside of described cavity is provided with fan, and described cavity rear wall is provided with the heat radiation window.
Wherein, described cavity wall is provided with control circuit and voltage-regulation distributor circuit, is used to control described fan, and described circuit is provided with operation keyboard.
Wherein, the front end in described stack shell space also is provided with the stack shell pore, and described valve and described stack shell pore are communicated with, and described gas flow sensor air intake opening passes described stack shell pore.
Wherein, the rear end of described stack shell is provided with a plurality of slots, and described cavity antetheca is provided with a plurality of latches that cooperate with described slot.
Wherein, described cavity rear wall by a plurality of screw retention on described cavity wall.
Wherein, described cavity wall is provided with battery compartment, is provided with accumulator in it, and described cavity rear wall is provided with power switch.
A kind of method of using above-mentioned constant current gas sampling assembly comprises step:
S1, gas collector is inserted valve, gas flow and sampling time are set, after accomplishing the setting up start gas sampling assembly by operation keyboard;
S2, fan begin to rotate discharges the gas in the cavity by the heat radiation window, the forward part of cavity produces negative pressure, under the atmospheric pressure effect, gas enters gas flow sensor by described gas collector from described valve, enter described inside cavity from described gas flow sensor again, discharge from described heat radiation window by described fan at last;
S3, when reach the sampling time of setting working time, the operating voltage that described control circuit cuts off described fan quits work it.
Wherein, in step S2, also comprise: in the rotation process of described fan, described gas flow sensor produces electric signal and the input control circuit that is directly proportional with current gas flow size, described control circuit is judged the electric signal of input, if the identical operating voltage that then continues the described fan of maintenance of the electric signal of input with the analog value of set gas flow, if the electric signal of input is different with the analog value of set gas flow, then described control circuit is adjusted the operating voltage of fan, and is identical with set gas flow until current gas flow.
(3) beneficial effect
Technique scheme of the present invention has following advantage: by using fan and utilizing control circuit and the voltage-regulation distributor circuit, make that gas can continuous flow and constant flow, thereby make the degree of accuracy of sampling apparatus higher and easy to operate.By not using surge flask, temperature control equipment, flowmeter etc., make that cost reduces, volume reduces.By not using membrane pump, cavity is made with sound insulating material and is made noise reduce.
Description of drawings
Fig. 1 is the structural representation of constant current gas sampling assembly embodiment of the present invention.
Wherein, 1: valve; 2: stack shell; 3: slot; 4: latch; 5: the gas flow sensor air intake opening; 6: gas flow sensor; 7: the gas flow sensor gas outlet; 8: the cavity antetheca; 9: cavity; 10: fan; 11: cavity wall; 12: wiring board; 13: control circuit; 14: operation keyboard; 15: display; 16: the voltage-regulation distributor circuit; 17: battery compartment; 18: accumulator; 19: the battery compartment lid; 20: screw; 21: the charger socket; 22: the heat radiation window; 23: power switch; 24: the cavity rear wall; 25: the stack shell space; 26: the stack shell pore; 27: cavity antetheca pore.
Embodiment
Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.
Be illustrated in figure 1 as the synoptic diagram of constant current gas sampling assembly of the present invention, comprise: stack shell 2, gas flow sensor 6, cavity 9, fan 10 and control circuit 13 etc.
Can comprise cavity wall 11 and cavity antetheca 8 and cavity rear wall 24 by the cavity 9 that sound insulating material is made.Cavity 9 is inner to be formed a front portion and is divided into rounded back section and is divided into square space, and the front portion is divided into circle and helps being provided with fan 10, and the rear portion is divided into square usefulness and is beneficial to control circuit etc. is set.Cavity antetheca 8 is provided with cavity antetheca pore 27, is communicated with cavity 9 thereby cavity antetheca pore 27 penetrates cavity antetheca 8, also is provided with a plurality of latches 4 on the cavity antetheca 8.Cavity rear wall 24 is fixed on the rear end of cavity wall 11 by a plurality of screws 20.Fan 10 is arranged on the forward part in the cavity 9.Wiring board 12 is arranged on the rear portion of cavity wall 11, and the inboard of wiring board 12 is provided with control circuit 13 and voltage-regulation distributor circuit 16, and the outside of wiring board 12 is provided with display 15 and operation keyboard 14.Battery compartment 17 and battery compartment lid 19 also are arranged on the rear portion of cavity wall 11, are provided with accumulator 18 in the battery compartment 17.Also can directly use external power supply in an embodiment of the present invention.Cavity rear wall 24 is provided with the charger socket 21 that is used for accumulator 18 chargings, heat radiation window 22 that is used to dispel the heat and power switch 23.
The front end of stack shell 2 is provided with valve 1, and the front end in the stack shell space 25 of stack shell 2 inside is provided with stack shell pore 26, and valve 1 penetrates stack shell pore 26 and is communicated with stack shell space 25.The rear end of stack shell 2 is provided with the slot 3 that cooperates with a plurality of latches 4, makes stack shell 2 and cavity 9 combinations.
Gas flow sensor 6 is arranged in the stack shell space 25, himself have air intake opening 5 and gas outlet 7, air intake opening 5 is inserted in the stack shell antetheca pore 27, thereby is communicated with the gas of being sampled, gas flow sensor gas outlet 7 is inserted in the cavity antetheca pore 27, thus with the internal communication of cavity 9.The shape in stack shell space 25 matches with the shape of gas flow sensor 6.
The specific operation process of apparatus of the present invention embodiment is: with gas collector (activated charcoal detector tube for example, miniature sampling head or solid adsorbent pipe) access valve 1, turn on the power switch 23, whether observation display 15 the display power supply under-voltage, if show the under-voltage charging that then needs, if it is not under-voltage then by pressing operation keyboard 14 and observation display 15 is provided with gas flow and sampling time, finish after being provided with by the start key on the operation keyboard, fan 10 begins to rotate discharges the gas in the cavity 9 by heat radiation window 22, cavity 9 forward parts produce negative pressure space, like this under the atmospheric pressure effect, gas enters gas flow sensor 6 by gas collector from valve 1, enter cavity 9 inside from gas flow sensor 6 again, be discharged from from heat radiation window 22 by fan 10 at last, in this process, gas flow sensor 6 can produce electric signal and the input control circuit 13 that is directly proportional with current gas flow size, the electric signal of 13 pairs of inputs of control circuit is judged, then continue the operating voltage that fan 10 is given in maintenance if the electric signal of input is identical with the analog value of set gas flow, the rotating speed of fan 9 is remained unchanged.If the electric signal sent here is different with the analog value of set gas flow, then control circuit 13 is adjusted the operating voltage of fan 10, stop adjustment until the analog value of the electric signal of gas flow sensor 6 input and set gas flow is identical, and keep corresponding work voltage to give fan 10, thereby make fan 10 keep corresponding rotating speeds to keep gas flow constant.When sampling working time to during the working time that sets in advance, the operating voltage that control circuit 13 cuts off fans 10 quits work fan 10, finishes sampling work powered-down switch 23.
The advantage of gas constant current sampling apparatus of the present invention is as follows: 1, utilize the fan characteristics of mobile gas continuously, and place cavity to allow gas flow in fan along a predetermined pipeline, its flow size is directly proportional with the rotating speed of fan, and rotating speed is directly proportional with the motor input voltage of fan, just can reach the purpose of automatic adjustments of gas flow size by regulating this voltage automatically; 2, because the noise of fan is littler than membrane pump, again because fan places cavity, and cavity can be made by sound insulating material, so this method can reach the purpose of reducing noise.3, fan substitutes membrane pump and surge flask, makes device volume little, is easy to carry.4, when utilizing fan sampling, the heat of generation such as control circuit is also dispelled the heat, prolonged the serviceable life of installing.
The above only is embodiments of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the technology of the present invention principle; can also make some improvement and modification, these improve and modification also should be considered as protection scope of the present invention.