CN2034279U

CN2034279U - Thermodesorption flash feeder

Info

Publication number: CN2034279U
Application number: CN 88218080
Authority: CN
Inventors: 廖焕然; 周勤秉
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-06-25
Filing date: 1988-06-25
Publication date: 1989-03-15

Abstract

The utility model relates to a thermal desorption flash evaporation feeder, which belongs to a device which feeds samples for a gas chromatograph or a color mass spectrograph. The thermal desorption flash evaporation feeder is composed of a sample feeding device (1), a plingower supply control device (12) and a bracket (2). The sample feeding device (1) comprises a sampling tube (28), a thermal desorption device (29), a refrigerating device (31), concentrated flash evaporation sample feeding tubes (46, 32 and 3) and a gas path switching system with an electromagnetic scavenging air valve (26), a mechanical scavenging air valve (30) and a synchronous switch (25). The power supply controlling device (12) comprises a control part for thermal desorption temperature, a control part for refrigerating device temperature, a water supply alarming part and a control part for flash evaporation heating time. The thermal desorption flash evaporation feeder has short sample feeding time; the thermal desorption flash evaporation feeder can improve the sensitivity of an analytical instrument, and can adapt to analyzing organic samples with a high boiling point under high humidity.

Description

Thermodesorption flash feeder

The utility model relates to a kind of gas chromatograph or look---sampling device of mass spectrometer sampling of giving.

To collection and the analysis that contains organic air sample,---thermal desorption method is better than solid adsorbent---the solvent desorption method that generally believes solid adsorbent both at home and abroad.Domestic thermal desorption method is started late, no matter be the cold-trap of desorb in glass syringe or liquid nitrogen, dry ice and cryosel, perhaps desorb does not all form the instrument of complete specification in Dewar bottle.Generally be with using with piecing together, the making and the assembly of device are multifarious, so that make complex operation, dangerous, because cold doubt and absorption of sample on vessel usually makes last Measurement results on the low side, especially the analysis of incompatibility high boiling point organic compound.Domestic a kind of 8021 types of once producing concentrate sampler, come down to freeze concentration sampling---thermal desorption sampling device, this device is sampled with airbag and glass syringe, not only, can not be adapted to high boiling point organic compound, and the freeze concentration sampling is condensed airborne water vapour simultaneously because of the condensation and the absorption of sample, bring very big difficulty to gas chromatographic analysis, even at all can not with look---mass spectrometer coupling because cycles of concentration is low, sensitivity only can only improve two orders of magnitude.Though abroad have various can with gas chromatograph or look---the thermal desorption concentrated sample introduction device that mass spectrometer is online, their adopt liquid nitrogen cooling mostly, and liquid nitrogen is not popularized in China at present, the source difficulty, loss is serious again.External cold-trap vaporization sample introduction has two kinds of forms, and the one, utilize the hot gas of gas chromatograph calibration cell, but the incompatibility higher-boiling compound.Another kind is the flash distillation sampling technique that adopts the end to reveal, but need make cold-trap intensification vaporization sample introduction in 40 seconds, so that sample injection time is long.

The purpose of this utility model, be to gas chromatograph or a kind of injector of suitable China's national situation can be provided with the analytical instrument (as look-mass spectrometer) of gas chromatograph coupling, improving the analytical instrument sensitivity of coupling, and adapt to the analysis of high boiling trace under the high humidity environment or ultramicron organic gas; Make air sample need not do any pre-treatment, thereby simplify procedures, take measures to shorten sample injection time simultaneously.

The utility model is realized as follows.Referring to Fig. 1, this injector is made up of sampling device (1), power control (12) and support (2) three parts.Sampling device (1) is sampled sample through concentrating---after thermal desorption---cold-trap concentrates---the flash distillation sample introduction process, give gas chromatograph or look---and mass spectrometer carries out test analysis.Power control (12) carries out various controls to sampling device (1), comprises thermal desorption temperature control part branch, the control of refrigerator temperature and part and flash distillation control section heat time heating time of reporting to the police that supply water.Support (2) then is a stator in sampling device (1) side, so that sampling device (1) is fixed on gas chromatograph or look---and on the mass spectrometric main frame.Referring to Fig. 2, sampling device (1) is mainly by sampling pipe (28), pyrolysis haustorium (29), refrigerator (31), concentrated flash distillation sample introduction pipe (46,32,3) and comprise that electromagnetism scavenging air valve (26), mechanically ventilated valve (30) and the nitrogen gas circuit switched system of change-over switch (25) synchronously form.The sampling pipe (28) of the efficient solid adsorbent (27) that concentrates is housed, after the on-the-spot normal temperature of air pollution concentrates the airborne organism of collection, insert the center, concavity space of the pyrolysis haustorium (29) of sampling device (1), give pyrolysis haustorium heating temperature control this moment, and feed nitrogen to sampling pipe simultaneously, concentrate in the sampling pipe is behind the thermal desorption desorption, import the concentrated flash distillation sample introduction pipe (46 in the refrigerator (31) that adopts semiconductor refrigerating element refrigeration temperature control, 32,3), concentrate once more through refrigeration, under the condition that feeds nitrogen, give and concentrate flash distillation sample introduction pipe (46,32,3) energising heating temperature control, with the instantaneous flash of steam of sample, form column cap " plug formula " sample introduction, enter chromatographic column (34) separation determination through gas chromatograph injection port (33), qualitative with retention time, peak height or peak area quantification.Sampling pipe (28) and concentrated flash distillation sample introduction pipe (46,32,3) in the above-mentioned course of work, all the time be connected with nitrogen as carrier gas, but when the sampling pipe that unloads the sampling pipe collected specimens or more renew, must cut off supply to sampling pipe nitrogen, also to continue simultaneously to keep to flash distillation sample introduction pipe and gas chromatograph that is attached thereto or look---the air feed of mass spectrometer gas circuit, for this reason, sampling device of the present utility model (1) also is provided with the nitrogen gas circuit switched system that comprises electromagnetism scavenging air valve (26), mechanically ventilated valve (30) and synchronous change-over switch (25).

From above design of the present utility model as can be seen, refrigerator refrigeration is to adopt semiconductor element and do not adopt China's source liquid nitrogen of still not too popularizing of difficulty relatively at present, relatively is fit to the present national conditions of China; Because sampling pipe is equipped with the strong efficient solid adsorbent that concentrates of hydrophobicity, cycles of concentration height (than the high 3-4 of direct injected more than the order of magnitude); And thermal desorption, refrigerator refrigeration concentrate once more and flash distillation sample introduction process has guaranteed the quantitative recovery of sample, thereby can be so that gas chromatograph or look---multiple that mass spectrometric sensitivity improves is exactly the cycles of concentration when concentrating sampling, solid adsorbent in the sampling pipe is because hydrophobicity is strong, so be applicable to the sampling of high humidity environment air simultaneously; Owing to adopted advanced flash evaporation technology, the flash of steam temperature can reach about 380 ℃, thus be applicable to the analytical test of high boiling point organic compound, and the sample injection time of quantitatively vaporizing only needs 10～15 seconds, and the flash distillation sample injection time shortens greatly outside the comparator.Adopt above-mentioned sampling device, behind the collection in worksite air sample, need not do the processing of any chemistry or physics, just can directly go up the machine assay determination, thereby simplify running program, saved the time with sampling pipe.

Below in conjunction with accompanying drawing the utility model is described in further detail.

Fig. 1 is a shape assumption diagram of the present utility model;

Fig. 2 is the structural principle synoptic diagram of sampling device of the present utility model;

Fig. 3 is a kind of concrete structure figure of sampling device;

Fig. 4 is power control and gas circuit switched system schematic diagram.

Referring to Fig. 3 and Fig. 4, sampling pipe (28) is the glass tube of the long 100mm of an internal diameter 4mm, interior dress 100mg35～60 purpose Tenax-GC or homemade AS-3 solid adsorbent (27), two ends recycle silicon alkanisation glass wools (39) fixed adsorbents (27).Sampling pipe (28) one terminations have sampling pipe fixed part (36), the middle pressure with silicon rubber pad (38), the axial sample filling orifice (4) of sampling pipe fixed part (36) is connected with sampling pipe (28) inside by the endoporus of silicon rubber pad (38), and sample filling orifice diameter is about 2mm.The other end of sampling pipe (28) and mechanically ventilated valve (30) join, the middle pressure with silicon rubber pad (44).The endoporus that the inner mechanical valve draft tube (42) vertically of mechanically ventilated valve (30) is passed silicon rubber pad (44) enters in the sampling pipe, the endcapped of mechanical valve draft tube (42) in sampling pipe (28) has the aperture (43) that is connected with mechanical valve draft tube (42) inside on its afterbody tube wall.During work, carrier gas and all after aperture (43) imports mechanical valve draft tube (42), enter again through the sample behind the thermal desorption desorption and to concentrate flash distillation sample introduction pipe (46,32,3).The profile of sampling pipe fixed part (36) is the garden bar, screw thread is arranged on the bar, be with the nut of a stationkeeping on the screw thread, garden bar by rotation sampling pipe fixed part (36), both can make its silicon rubber pad that promotes to oppress sampling pipe (28) two ends forward (38,44) and make sampling pipe fastening, and it is retreated and loosened sampling pipe and then sampling pipe is taken out.Pyrolysis haustorium (29) is to make a saddle-shaped concavity piece with metallic aluminium, setting-in is used for to the heating wire (41) of pyrolysis haustorium (29) heating and the platinum resistance of using as the feedback temperature signal (40) respectively on two baseplanes, notes the pyrolysis haustorium (29) of they and metal is performed insulation processing.Heating wire (41) is supplied with heating power supply by the digital temperature regulator (10) that the thermal desorption temperature control part divides, and platinum resistance (40) feeds back to digital temperature regulator (10) so that temperature is controlled with the temperature signal of pyrolysis haustorium (29).Sampling pipe (28) places the center in pyrolysis haustorium (29) concavity space, can accept the heat that the pyrolysis haustorium distributes effectively.Concentrate flash distillation sample introduction pipe and be divided into stem pipe (46), central tube (32) and afterbody pipe (3) three parts.One end of stem pipe (46) is connected with mechanical valve draft tube (42), and central tube (32) places among the cold-trap (48) of refrigerator (31), and afterbody pipe (3) is connected with gas chromatograph injection port (33).All internal diameter and the external diameter than stem pipe (46) and afterbody pipe (3) is thick with external diameter for central tube (32) internal diameter, holds the solid adsorbent (51) of 35-60 order alumina particle and through the freezing sample treat the flash distillation sample introduction that concentrates once more in order to its inside.The outer wall of central tube (32) winds the heating wire (47) for flash distillation energising heating, should add the insulant insulation between heating wire (47) and central tube (32) outer wall.In the present embodiment, stem pipe (46) is the gapless stainless steel tube that adopts internal diameter 0.5～1.5mm with afterbody pipe (3), and central tube (32) is to adopt the gapless stainless steel tube of internal diameter 2～3mm.Heating wire (47) two ends are electrically connected with the outer wall of stem pipe (46) and afterbody pipe (3) respectively, and the terminal outer wall of afterbody pipe (3) then is electrically connected with the utility model apparatus housing ground end.Like this, if at concentrated flash distillation sample introduction pipe (46,32,3) two ends with the formed parallel resistance of heating wire (47) apply a voltage, then on two sub-resistances of parallel resistance, all can flow through electric current and generate heat, because the big heat of central tube (32) this section resistance is many, makes the at high temperature instantaneous flash vaporization of sample of freeze concentration, gives chromatograph injection port (33) by afterbody pipe (3).Flash distillation control section heat time heating time removes above-mentioned concentrated flash distillation sample introduction pipe (46,32,3) with the formed parallel resistance of heating wire (47) outside, also comprise flash distillation pushbutton switch (23), the time relay (9), pilot relay (60), power transformer (61), flash distillation indicator current table (14) flash distillation Current Regulation potentiometer (21), the front end outer wall of the stem pipe (46) of one end of potentiometer (21) and concentrated flash distillation sample introduction pipe is electrically connected, and is the normally opened contact of pilot relay (60) (60-1) and (60-2).During the flash distillation sample introduction, the time of on the time relay (9), reserving the flash distillation sample introduction, start flash distillation pushbutton switch (23), then power transformer (61) can be by flash distillation Current Regulation potentiometer (21) to concentrated flash distillation sample introduction pipe (46,32,3) with the formed parallel resistance power supply of heating wire (47).Flash temperature can change with flash distillation Current Regulation potentiometer (21) by regulating the time relay (9), and the AC power that present embodiment power transformer (61) is supplied with is 36V15A, and flash temperature is adjustable controlled at 50 ℃-380 ℃.Refrigerator (31) is by the cold-trap of making the sylphon shape (48), semiconductor cooling element (49) and semiconductor cooling element (49) is had the cold water of thermolysis (stream leads to box (52) to be formed.Three utmost point semiconductor cooling elements (49) pad freezes to cold-trap in the bottom of cold-trap (48), semiconductor cooling element (49) is then divided by the refrigerator temperature control part supplies with working power, the refrigerator temperature control part divides except that semiconductor cooling element (52), also comprise digital temperature meter (11), platinum resistance (50), power transformer (62), rectification circuit (63), inductance element (64), refrigeration electric current indicating gauge (13), refrigerator power switch (17), platinum resistance (50) is contained in the inside of cold-trap (48), its effect is that the temperature signal in the cold-trap (48) is fed back to digital temperature meter (11), with control cold-trap (48) temperature inside, bottom in semiconductor cooling element (49), cold water is housed, and (stream leads to box (52), the heat that produces when taking away semiconductor cooling element (49) work by the water (gas) of circulation, so that the cooling element heating is burnt out, (5) be water inlet (gas) mouth, (6) are water outlet (gas) mouth.In order to guarantee enough circulation water (gas) amount heat radiations, the utlity model has (gas) warning part of cutting off the water supply, promptly (stream leads on the box body of box (52) and adorns a temperature detect switch (TDS) (53) at cold water, when circulation water (gas) is measured undersupply or is stopped supplying, temperature detect switch (TDS) (53) temperature rises, and make and break contact disconnects, and causes normally closed contact (65-1) action of relay (65), pilot lamp (22) is lighted, buzzer (66) sounding alarm.

The synchronous change-over switch (25) that is used for the switching of carrier gas gas circuit is positioned at the valve body of mechanically ventilated valve (30), and it is the mechanically actuated switch of mechanically ventilated valve (30), is again the electric controling switch of electromagnetism scavenging air valve (26) simultaneously.When this switch is pulled to a dislocation, the valve body reach of mechanically ventilated valve (30), mechanical valve draft tube (42) on the valve body also moves forward, aperture (43) on its afterbody tube wall is exposed in the sampling pipe (28) of silicon rubber pad (44) outside, meanwhile, change-over switch (25) makes the coil electricity of electromagnetism scavenging air valve (26) synchronously, control its valve and will enter the nitrogen of electromagnetism scavenging air valve (26) by wireway (37) introducing sampling pipe (28), aperture (43) on mechanical valve draft tube (42) tube wall imports in mechanical valve draft tube (42) pipe then, enter again and concentrate flash distillation sample introduction pipe (46,32,3); When synchronous change-over switch (25) is pulled to another dislocation, move behind the valve body of mechanically ventilated valve (30), mechanical valve draft tube (42) is moved after also, in aperture (43) the setback silicon rubber pad (44) on its afterbody tube wall and blocked, meanwhile, change-over switch (25) is with the dump of the coil of electromagnetism scavenging air valve (26) synchronously, control the nitrogen cut-out that its valve will enter sampling pipe (28), another valve that nitrogen changes by electromagnetism scavenging air valve (26) directly enters mechanical valve draft tube (42) through wireway (45), and then enter and concentrate flash distillation sample introduction pipe (46,32,3), so just can make when changing sampling pipe, both guarantee the continuous source of carrier gas in the gas chromatographic column, and stability of flow, to improve the sensitivity and the stability of instrument, guaranteed simultaneously the carrier gas sampling pipe of not flowing through, the concentrate in the pipe can not blown out and lose by nitrogen, thereby has improved sample recovery rate yet.

By above to detailed description of the present utility model, we can also see, owing to adopted mechanically ventilated valve of a tightly knit structure, reasonable in design, make it reach high temperature resistant (350 ℃), high pressure resistant (2-6 atmospheric pressure), no dead volume and non-staining requirement, thereby guaranteed that effectively sample quantitatively shifts among cold-trap in the thermal desorption process, improved the thermal desorption sample recovery rate.In addition,, make the temperature of heating, refrigeration and flash distillation adjustable controlled, and the energy numeral show and acousto-optic shows, has improved automaticity because power control adopts advanced temperature control time control and circuit water alarm system.

In the above description, silent Reference numeral is respectively in Fig. 1-Fig. 4: the handle (7) of loading and unloading sampling pipe; Flash distillation power light (8); Total power switch (15); Total power light (16); Refrigerator power light (18); Thermal desorption power switch (19); Thermal desorption power light (20); Power lead (24); Detecting device (35); General supply plug (54); General supply insurance (55); Pilot lamp current-limiting resistance (56)～(59).

Claims

The thermal desorption flash distillation injector of 1, a kind of and gas chromatograph or look--the online use of mass spectrometer, comprise sampling device (1) and power control (12), it is characterized in that, described power control (12) comprises thermal desorption temperature control part branch, the control of refrigerator temperature and part and flash distillation control section heat time heating time of reporting to the police that supply water, and described sampling device (1) comprising:

A, a sampling pipe (28), its two ends are connected with sample filling orifice (4) and mechanical valve draft tube (42) in the sampling pipe fixed part (36) respectively, and strong, the efficient concentrated solid adsorbent (27) of hydrophobicity is equipped with in sampling pipe (28) inside;

B, a pyrolysis haustorium (29), it is to constitute at an embedded dress heating wire of concavity metal stick (41), described sampling pipe (28) places the center in the concavity space of pyrolysis haustorium (29);

C, a refrigerator (31), it is by the cold-trap of making sylphon shape (48), semiconductor cooling element (49) and semiconductor cooling element (49) is had the cold water of thermolysis (stream leads to box (52) to be formed;

D, a concentrated flash distillation sample introduction pipe (46,32,3), one end of its stem pipe (46) is connected with mechanical valve draft tube (42), central tube (32) places among the cold-trap (48) of refrigerator (31), afterbody pipe (3) is connected with the injection port (33) of gas chromatograph, all internal diameter and the external diameter than stem pipe (46) and afterbody pipe (3) is thick with external diameter for central tube (32) internal diameter, the solid adsorbent (51) of 35-60 order alumina particle is housed in the central tube (32), the outer wall of central tube (32) is wound with heating wire (47), heating wire (47) two ends are electrically connected with the outer wall of stem pipe (46) and afterbody pipe (3) respectively, one end of the front end outer wall of stem pipe (46) and flash distillation Current Regulation potentiometer (21) is electrically connected, and the terminal outer wall of afterbody pipe (3) then is electrically connected with casing ground end;

E, the nitrogen gas circuit switched system that constitutes by electromagnetism scavenging air valve (26), mechanically ventilated valve (30) and synchronous change-over switch (25).
2,, it is characterized in that the solid adsorbent of being adorned in the described sampling pipe (28) (27) is 100mg35～60 purpose Tenax-GC or homemade AS-3 according to the thermal desorption flash distillation injector of claim 1 regulation.
3, according to claim 1 or the 2 thermal desorption flash distillation injectors of stipulating, the central tube (32) that it is characterized in that described concentrated flash distillation sample introduction pipe (46,32,3) adopts internal diameter 2～3mm gapless stainless steel tube, and stem pipe (46) and afterbody pipe (3) all adopt the gapless stainless steel tube of internal diameter 0.5～1.5mm.
4,, it is characterized in that described thermal desorption temperature control part branch comprises digital temperature regulator (10), heating wire (41) and is flush-mounted in platinum resistance (40) on the pyrolysis haustorium (29) according to the thermal desorption flash distillation injector of claim 1 regulation.
5, thermal desorption flash distillation injector according to claim 1 regulation, it is characterized in that described refrigerator temperature control part branch comprises digital temperature regulator (11), power transformer (62), rectification circuit (63), inductance element (64), refrigeration electric current indicating gauge (13), semiconductor cooling element (49) and be contained in platinum resistance (50) in cold-trap (48) box, described refrigerator supplies water to report to the police and partly comprises temperature detect switch (TDS) (53), relay (65), pilot lamp (22) and buzzer (66), temperature detect switch (TDS) (53) are contained in the cold water of described refrigerator (31), and (stream leads on the box body of box (52).
6,, it is characterized in that described flash distillation control section heat time heating time comprises flash distillation pushbutton switch (23), the time relay (9), pilot relay (60), power transformer (61), flash distillation electric current indicating gauge (14), flash distillation Current Regulation potentiometer (21) and by concentrated flash distillation sample introduction pipe (46,32,3) and the formed parallel resistance of heating wire (47) according to the thermal desorption flash distillation injector of claim 1 regulation.