TWM480420U - Concentrated gas sampling thermal desorption apparatus - Google Patents

Description

Thermal desorption device after concentration of sample gas to be tested

The novel creation system relates to a thermal desorption device for concentrating a sample gas to be tested, in particular, a metal heat pipe is provided for inserting a sample gas capture tube to be tested, and the steps of rapid heat collection and cooling capture can be performed inside the sample.

The so-called sampled gas after concentration is a thermal desorption device, which is capable of capturing low-concentration gas samples, and after concentration and thermal desorption, produces a high-concentration sample gas, so that the detector can analyze the components of the sampled gas to obtain qualitative and quantitative samples. the result of.

As shown in FIG. 1 and FIG. 2, the conventional thermal desorption apparatus 1 for sampling a sample gas to be tested basically comprises a sample gas capturing tube 10 to be tested, a heating coil 11 and a cooling element 12. The sample gas capturing tube 1 to be tested is a glass product, and the tube can be filled with a chemical adsorbent 13 to capture the passed sample gas molecules by cooling to produce a concentration effect.

The heating coil 11 is wound by a multi-layer composite structure heating wire 110, and includes a metal core 111 surface covering a mica layer 112 and a stainless steel surface layer 113. This special heating wire 110 is similar in appearance to a general metal wire, but the high temperature insulating property of the intermediate mica layer 112 prevents the short circuit of the heating coil 11. If the heating coil 11 is short-circuited, the current will only be taken to the shortest path. As a result, only the section through which the current passes is locally heated. This will prevent the sample gas capturing tube 10 to be tested from being uniformly heated and cannot reach the original designed operating temperature ( 250 ° C ~ 300 °C), resulting in incomplete sample gas desorption, poor analytical results or too low concentration to analyze.

The main reason for manufacturing the sample gas capturing tube 10 to be tested with glass is that the glass is an inert material, and it is not easy to chemically react with the sample gas to be tested at a high temperature, which helps to maintain the sample gas to be tested while the sample gas to be tested is being transported. Will not deteriorate. Since it is necessary to consider the particle size of the chemical adsorbent 13 filled in the tube of the sample gas trapping tube 10 to be tested, and the sample gas to be tested is injected into the analytical instrument, it is required to pass through a packed column or a capillary column (Capillary). Column) and other component transfer.

The diameter of such an adapter element is rather narrow. For example, the diameter of the column port is only 1/8 inch, and the diameter of the capillary column is only 0.32 mm and 0.25 mm. Therefore, the standard sample gas to be sampled is captured. The tube 10 is a 1/8 inch (3.175 mm) glass tube, the purpose of which is to avoid the existence of "unprofitable volume". The so-called "unhelpful volume" is based on the fact that if the sample gas to be tested flows from a large-diameter pipe to a small-diameter pipe, the sample gas to be tested can easily recirculate at the place where the pipe diameter changes and diffuse in the pipeline. This diffusion phenomenon causes the peak shape of the sample gas to be tested to widen and produce a tailing phenomenon, and this phenomenon is not appreciated in chemical analysis techniques.

After the cooling capture step, the sample gas is adsorbed to the chemical attachment agent. In the heating step of thermal desorption, the heating coil must be heated to 250 ° C ~ 300 ° C in a very short time, so that the sample gas adsorbed in the chemical agent is quickly detached, in order to obtain a correct, symmetrical signal peak shape and Excellent analytical results. If the rate of desorption temperature rises too slowly, it may cause widening and tailing of the signal peak shape, which is a phenomenon that is not seen in general chemical analysis work. In order to achieve the effect of rapid desorption, the heating coil 11 must be able to withstand a large current in order to climb the temperature to a range of 250 ° C to 300 ° C in the shortest time.

The heating wire 110 is composed of a metal core 111, a mica layer 112 and a stainless steel surface layer 113. It has a certain stiffness during winding and cannot be excessively bent. Otherwise, the inner metal core 111 may be over. The bent portion is thinned or broken; only the thinned metal core 111 may pass the quality control test of the production line, and may suddenly melt when the rated current is passed, resulting in failure of the detection operation without warning. The diameter of the sample gas capturing tube 10 (glass tube) to be tested is only 1/8 inch. In the winding processing practice, the heating coil 11 is wound outside such a small glass tube, and only the wire diameter of 1.4 mm or less can be selected. The heating wire 110 is wound tightly. If the wire diameter is too thick, it cannot be closely attached to the sample gas capturing tube 10 to be tested, and the quality defect of being thinned or broken at the corner is easy to occur.

Although it is practical to use a heating wire 110 having a wire diameter of 1.4 mm or less, the heating coil 11 is wound around a glass tube having a diameter of only 1/8 inch, thereby avoiding the above-mentioned thinning or breaking of the wire core at the corner. The problem of 111, but will still face two problems: First, due to the thickness of both the mica layer 112 and the stainless steel surface layer 113 being buckled, the wire diameter of the metal wire core 111 is relatively small, so that a large current cannot be applied, so that The power of the heating coil 11 is limited, and the ideal effect of rapid temperature rise cannot be achieved. Secondly, the metal core 111 of the heating wire 110 is too thin. When the winding operation is not smooth, the local line segment is subjected to abnormal stretching and becomes special. Fine, during the process of energization, the details may still melt and break due to overheating, which will affect the quality reliability and service life of the heating coil, and affect the stability of the analysis operation.

In addition, the conventional sampling gas capturing tube 10 to be tested must be replaced after a period of use, and the heating coil 11 is tightly wound around the surface of the sampling gas capturing tube 10 to be tested, and the heating and cooling cycle is repeated for a long period of time. It will be gradually distorted and deformed even on the sample gas capturing tube 10 to be tested, which makes it difficult to exchange, and it is easy to extract the sample gas capturing tube 10 to be tested (glass In the case of glass, there is an accident of breaking or breaking. Furthermore, since it is quite time-consuming and complicated to fill the chemical adsorbent 13 in the sample gas capturing tube 10 to be tested, if the sampling gas capturing tube 10 to be tested is broken during the replacement process, or the heating coil 11 is suddenly burned, Will make everything ready for the job to come back.

In order to solve the problem that the heating coil 11 can not withstand a large current due to the small diameter of the heating coil 11 being too small, the heating coil 11 can not be subjected to a large current, and at the same time, in order to solve the problem of sampling the gas capturing tube 10 (glass) The present invention provides an improved thermal desorption device for a sample gas to be tested which can effectively solve the above problems, and the technical feature is that a sample gas capturing tube is heated by a metal heat pipe, and the heating coil can be recirculated. The sample gas capturing tube to be tested is indirectly heated on the metal heat pipe.

Since the diameter of the metal heat pipe is larger than that of the conventional 1/8 inch sample gas capturing pipe 10 (glass) to be tested, the novel creation can utilize the thick multilayer composite structure heating wire 110 to wind the heating coil 11 to withstand higher. The current reaches the effect of rapid heating of higher power, solving various problems arising from the fact that the metal wire is too thin. Since the heating coil which can be heated rapidly can help the detection operation to obtain a better desorption peak type, the improvement of the indirect heating of the glass tube by the metal heat-conducting tube makes the replacement of the sample gas capturing tube to be tested easier, and will be reduced. Measure the chance of damage to the sampling gas capture tube to achieve cost savings.

The novel thermal desorption device for sample gas to be tested is provided with at least one metal heat pipe, one heating coil, a sample gas capturing tube to be tested, and a cooling element; wherein the heating coil is spirally surrounded around the metal heat pipe The cooling element is on the periphery of the heating coil. The metal heat pipe is inserted into the sampling gas capture tube to be tested, and the cooling capture and the emergency addition are completed in the tube. Thermal desorption. Preferably, a temperature sensing element can be added to monitor the temperature of the heating coil or the metal heat pipe to determine the progress state of the thermal desorption.

1‧‧‧After the sample gas to be tested is concentrated, the thermal desorption device

2‧‧‧The thermal desorption device after the sample gas to be tested is concentrated

3‧‧‧The thermal desorption device after the sample gas to be tested is concentrated

10‧‧‧Sampling gas capture tube to be tested

11‧‧‧heating coil

12‧‧‧ Cooling components

13‧‧‧Chemical adsorbent

20‧‧‧Metal heat pipe

21‧‧‧heating coil

22‧‧‧ Cooling element

23‧‧‧Chemical adsorbent

24‧‧‧ Temperature sensing element

25‧‧‧Sampling gas

26‧‧‧Pump pump

27‧‧‧ Carrier gas

28‧‧‧Detecting instruments

29‧‧‧ Spacer components

30A‧‧‧First metal heat pipe

30B‧‧‧Second metal heat pipe

31‧‧‧heating coil

32‧‧‧ Cooling components

34‧‧‧ Temperature sensing element

110‧‧‧heating line

111‧‧‧Metal heart

112‧‧‧mica layer

113‧‧‧Stainless steel surface

210‧‧‧heating line

211‧‧‧Metal core

212‧‧‧mica layer

213‧‧‧Stainless steel surface

310‧‧‧heating line

FIG. 1 is a schematic diagram showing the basic structure of a conventional thermal desorption device for sampling a sample gas to be measured.

2 is a schematic view of a conventional sample gas trapping tube (glass) to be combined with a heating coil.

FIG. 3 is a schematic diagram showing the basic structure of a thermal desorption device after concentration of a sample gas to be tested according to the present invention.

FIG. 4 is a schematic view showing the adsorption operation of the thermal desorption device after the sample gas to be tested in FIG. 3 is concentrated.

FIG. 5 is a schematic diagram of the thermal desorption operation of the thermal desorption device after the sample gas to be tested in FIG. 3 is concentrated.

FIG. 6 is a schematic view showing a modified embodiment of the thermal desorption device after the sample gas to be tested in FIG. 3 is concentrated.

FIG. 7 is a schematic view showing another modified embodiment of the thermal desorption device after the sample gas to be tested in FIG. 3 is concentrated.

[reference photo]

Photograph 1: The sample gas trapping tube (glass) to be tested in the thermal desorption device after the sample gas to be measured is used for concentration.

As shown in FIG. 3, an embodiment of the thermal desorption device 2 for sampling gas to be tested according to the present invention is provided with at least one metal heat pipe 20, a heating coil 21, and a sample gas capturing tube 10 to be tested. a cooling element 22; wherein the inside of the sample gas capturing tube 10 to be tested is filled with a chemical adsorbent 23, and the cooling element 22 is attached to the periphery of the heating coil 21, and transmits heat through the surface of the heating coil 21 and the metal heat transfer tube 20, The indirect cooling passes through the gas in the sample gas to be tested to capture the gas, so that the cooled gas is adsorbed to the chemisorbent 23, thereby completing a step of cooling capture.

The heating coil 21 of the present embodiment is wound by a heating wire 210 to be sleeved outside the metal heat pipe 20, or spirally wound around the metal heat pipe 20 by a heating wire 210. Through the heat conduction of the metal heat pipe 20, the gas in the adsorbing chemical adsorbent 23 can be indirectly heated, and the gas is heated and quickly separated from the chemical adsorbent 23, thereby completing a heating step of thermal desorption.

Since the diameter of the metal heat pipe 20 configured by the novel creation is larger than the diameter of the conventional sample gas capturing pipe 10 to be tested, the limitation of the conventional structure can be broken, and the thick heating wire 210 is used to be wound into the heating coil 21. . For example, the heating coil 21 can be wound by a heating wire 210 having a wire diameter of 2 mm or more; compared with the heating wire 110 of the conventional device, the metal wire core 211 of the heating coil 21 of the present invention is thicker and can withstand higher Since the operating current can not only increase the temperature rise rate of the heating coil 21 by a strong current, but also prolong the service life of the heating coil 21 and the reliability of the product.

The heating wire 210 of the embodiment also includes a metal core 211, a mica layer 212 and a stainless steel skin 213. The mica layer 212 is interposed between the metal core 211 and the stainless steel surface layer 213 to provide high temperature insulation, and the stainless steel surface layer 213 provides the aforementioned cooling capture. The steps are related to the heat transfer required for the thermal desorption of the heating step. Preferably, a temperature sensing element 24 can be disposed in the heating coil 21 or the metal heat pipe 20 of the embodiment to monitor the working state of the heating coil 21.

Referring to the adsorption operation diagram of FIG. 4, in the cooling capture step of the trace chemical gas sampling, the thermal desorption device 2 of the novel sample gas to be tested can be pumped by an air pump 26 to make the sample to be tested. The gas 25 can flow through the sample gas capturing tube 10 to be tested, and through the cooling action of the cooling element 22, through the heat conduction of the stainless steel surface layer 213 of the heating coil 21 and the metal heat pipe 20, the sample flowing through the sample gas capturing tube 10 to be tested is sampled. The gas 25 is cooled and adsorbed by the chemisorbent 23, and since the sample gas 25 to be tested which is passed through is continuously adsorbed to the chemisorbent 23, the concentration is continuously increased until it meets the detectable range of the detecting instrument 28.

The cooling element of this embodiment may be constructed of a Thermoelectric Cooling Module; for example, a commercially available 40 mm x 40 mm x 5 mm chilled wafer provides the desired cooling function. With the cooling element of the present example, the temperature of the sample gas capturing tube 200 to be tested can be lowered to minus 40 degrees Celsius during cooling capture. The chemisorbent material 210 of the present embodiment may be selected from activated carbon or an adsorbent material having a high area ratio capable of capturing a sample gas (this is well known to those skilled in the art and will not be described herein).

Please refer to the schematic diagram of the thermal desorption operation of FIG. After the sampling gas capturing tube 10 to be tested completes the cooling capturing step, the sampling gas 25 to be tested is adsorbed to the chemical adsorbing agent 23; when the heating coil 21 is energized, the sampling gas capturing tube 10 to be tested is rapidly raised to the working temperature (250 ° C) ~300 ° C), the sample gas 25 to be tested adsorbed in the chemical adsorbent 23 can be quickly separated by the heat energy. At this time, the carrier gas 27 can be introduced from one end of the sample gas capturing tube 10 to be tested, and the chemical adsorbent 23 is removed. The sample gas 25 is sent to the detection instrument 28 for analysis. The key to this step is to make the heating uniform and rapid, and the more concentrated the desorption effect of the sample gas, to achieve the focusing effect in chemical chromatography.

Please refer to Figure 6. Since the metal heat pipe 20 after power-on will form an environment similar to a high-heat oven in an instant, in order to prevent the sample gas capturing tube 10 to be tested, only one side of the pipe wall is close to the metal heat pipe 20, and the other side is connected with the metal heat pipe 20. Separately, the wall of the sample gas capturing tube 10 to be tested is deformed due to uneven initial heat and cold. In view of this, in some cases, it is necessary to maintain a uniform gap between the sample gas capturing tube 10 to be tested and the metal heat pipe 20. This embodiment proposes to use a heat-resistant cotton sleeve or a heat-resistant fabric as the spacer member 29 between the sample gas capturing tube 10 to be tested and the metal heat-conducting tube 20 to avoid uneven heat and cold in the initial tube wall of the sample gas capturing tube 10 to be tested. And the problem of deformation.

Since the sample gas capturing tube 10 to be tested of the present embodiment is directly inserted into the metal heat pipe 20 without being in close contact with the heating coil 21, it becomes quite easy to replace, so that the change as shown in FIG. 7 can be considered. Example. After the sample gas to be tested in this embodiment is concentrated, the thermal desorption device 3 can simultaneously provide two jacks, respectively leading to a first metal heat pipe 30A and a second metal heat pipe 30B, wherein the first metal heat pipe 30A and The cooling element 32 is in contact, and the second metal heat pipe 30B is sleeved with the heating coil 31. The heating coil 31 of the present embodiment is also constituted by a heating wire 310, and a temperature sensing element 34 is disposed to monitor its operating state.

In use, the sample gas capturing tube 10 to be tested may be inserted into the first metal heat pipe 30A for cooling and capturing; or the sample gas capturing tube 10 to be tested subjected to the cooling capturing step may be inserted into the second metal heat pipe 30B for heat. Desorption step of heating. First metal guide of this embodiment The heat pipe 30A and the cooling element 32 are units that can be planned to be separately manufactured, and the second metal heat pipe 30B, the heating coil 31, and the temperature sensing element 34 can also be planned as another separately manufactured unit, so that the processes of the two are made. The parallel division of labor makes it easier to control the incoming product management and future maintenance operations.

Not all of the sample gas capturing tubes 10 to be tested applicable to the novel creation must be made of glass, depending on the chemical characteristics of the sampling gas 25; for example, stainless steel, Teflon or any chemical adsorption material 23 and sample gas may be selected. 25 The metal that produces the chemical reaction is made of a material.

The specific effect of the novel creation can break through the limitation, so that the diameter of the heating wire 210 can no longer be limited by the small diameter of the sample gas capturing tube 10 to be tested, and can be wound around the thick metal heat pipe 20, There are two advantages: First, the heating wire 210 can withstand a relatively large current, generating more heat per unit time to rapidly increase the temperature and achieve the effect of focusing; second, because of the diameter of the heating wire. Large, metal wire core 211 can also be thicker, more able to withstand high temperatures without breaking, deformation, increasing the stability of long-term use.

2‧‧‧The thermal desorption device after the sample gas to be tested is concentrated

10‧‧‧Sampling gas capture tube to be tested

20‧‧‧Metal heat pipe

21‧‧‧heating coil

22‧‧‧ Cooling element

23‧‧‧Chemical adsorbent

24‧‧‧ Temperature sensing element

25‧‧‧Sampling gas

26‧‧‧Pump pump

210‧‧‧heating line

Claims (10)

A thermal desorption device for concentrating a sample gas to be tested, comprising: a metal heat pipe; a sample gas trapping tube to be tested, which is filled with a chemical adsorbent for adsorbing a gas molecule, and can be inserted into the metal heat pipe Selectively performing a cooling capture step and a thermal desorption heating step; a heating coil is spirally sleeved on the periphery of the metal heat pipe; and a cooling element is coupled to the heating coil The surface of the heating coil is thermally conducted with the metal heat pipe to cool the sample gas capturing tube to be tested. The thermal desorption device of the sample gas to be tested as described in claim 1 further comprises a temperature sensing element connected to the heating coil for monitoring the working state of the heating coil. The thermal desorption device of the sample gas to be tested according to claim 1, wherein the heating coil is wound by a heating wire and sleeved on the metal heat pipe; wherein the heating wire comprises a metal a core, a mica layer, and a stainless steel skin, wherein the mica layer is between the metal core and the stainless steel outer layer. The thermal desorption device of the sample gas to be tested, as described in claim 1, further comprising a spacer element disposed between the metal heat pipe and the sample gas capturing tube to be tested, so that the metal heat pipe and the metal heat pipe A uniform gap is maintained between the sample gas trapping tubes to be tested. The thermal desorption device of the sample gas to be tested as described in claim 1, wherein the cooling element is a uniform cold wafer, and the heat is transmitted through the surface of the heating coil and the metal heat pipe to enter the sample gas to be tested. The gas molecules in the trap tube are cooled and adsorbed to the chemisorbent. The method of claim 1, wherein the heating coil is formed by a heating wire directly wound around the metal heat pipe; wherein the heating wire comprises a metal wire a core, a mica layer, and a stainless steel skin layer, wherein the mica layer is between the metal wire core and the stainless steel outer layer. A thermal desorption device for concentrating a sample gas to be tested, comprising: a first metal heat pipe for inserting a sample gas capture tube to be tested; a cooling element connected to the first metal heat pipe; and a second metal heat conduction a tube for inserting a sample gas capturing tube to be tested; and a heating coil sleeved around the second metal heat pipe. The method of claim 1, wherein the first metal heat pipe reduces the temperature of the sample gas trapping tube to be tested, and performs a cooling capture step. The thermal desorption device of the sample gas to be tested as described in claim 7 , wherein the second metal heat pipe can raise the temperature of the sample gas trapping tube to be tested, and perform a thermal desorption heating step. . The thermal desorption device of the sample gas to be tested as described in claim 7 further includes a temperature sensing element connected to the heating coil for monitoring the working state of the heating coil.