阅读说明：本技术 气体稀释装置与方法 (Gas dilution device and method ) 是由 王甫华 岑延相 吴曼曼 封荣贵 乔佳 陈家新 于 2020-12-31 设计创作，主要内容包括：本发明涉及一种气体稀释装置与方法,对标准气体进行稀释操作时,第一气路控制件控制第一进气管与第一出气管相连通,第二气路控制件控制第二出气管与第三出气管相连通,将稀释气体通入到混合罐内；第一气路控制件控制第二进气管与第一出气管相连通,第二气路控制件控制第二出气管与第三出气管相连通,将高浓度的标准气体通入到混合罐内；在流量控制器与压力检测器的作用下,可以将定量的稀释气体与定量的标准气体均通入到混合罐内进行混合得到预设浓度标准气体。由于包括有第二气路控制件与排气管,第二气路控制件可以控制第二出气管与排气管相连通,即在稀释步骤之前可以先进行润洗步骤,通过润洗步骤来提高高浓度的标准气体的稀释精度。(The invention relates to a gas diluting device and a method, when standard gas is diluted, a first gas circuit control part controls a first gas inlet pipe to be communicated with a first gas outlet pipe, a second gas circuit control part controls a second gas outlet pipe to be communicated with a third gas outlet pipe, and diluted gas is introduced into a mixing tank; the first gas circuit control part controls the second gas inlet pipe to be communicated with the first gas outlet pipe, the second gas circuit control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, and high-concentration standard gas is introduced into the mixing tank; under the action of the flow controller and the pressure detector, quantitative diluent gas and quantitative standard gas can be introduced into the mixing tank to be mixed to obtain the standard gas with preset concentration. The second gas path control part can control the second gas outlet pipe to be communicated with the exhaust pipe, namely, the rinsing step can be performed before the diluting step, and the diluting precision of the high-concentration standard gas is improved through the rinsing step.)

1. A gas dilution apparatus, comprising:

the gas path control part is used for controlling one pipeline in the first gas inlet pipe and the second gas inlet pipe to be communicated with the first gas outlet pipe and controlling the rest pipelines in the first gas inlet pipe and the second gas inlet pipe to be disconnected with the first gas outlet pipe, the first gas inlet pipe is used for introducing diluent gas, and the second gas inlet pipe is used for introducing high-concentration standard gas;

the gas inlet end of the gas flow controller is communicated with the first gas outlet pipe, and the gas outlet end of the gas flow controller is communicated with the second gas outlet pipe;

the second gas path control part is used for controlling the second gas outlet pipe to be communicated with the third gas outlet pipe or the exhaust pipe, the third gas outlet pipe is used for being communicated with the gas inlet end of the mixing tank, and the pressure detector is arranged on the second gas outlet pipe or the third gas outlet pipe.

2. The gas dilution device defined in claim 1, wherein the second inlet pipe is two or more.

3. The gas dilution device defined in claim 1, further comprising a third inlet pipe, the first control valve being configured to control one of the first, second, and third inlet pipes to communicate with the first outlet pipe and to control the remaining ones of the first, second, and third inlet pipes to be disconnected from the first outlet pipe.

4. The gas dilution apparatus of claim 1, wherein the first gas path control is a multi-position switching multi-way valve; the multi-position switching multi-way valve is provided with a first connector, a second connector and an air outlet, the first connector is communicated with the first air inlet pipe, the second connector is communicated with the second air inlet pipe, and the air outlet is communicated with the first air outlet pipe; the multi-position switching multi-way valve can be used for controlling one of the first interface and the second interface to be communicated with the air outlet and controlling the rest interfaces of the first interface and the second interface to be disconnected with the air outlet.

5. The gas dilution apparatus defined in claim 4 further comprising a heating element for heat treating the first gas control circuit.

6. The gas dilution device defined in claim 5 further comprising a temperature measurement member and a temperature retention member; the temperature measuring part is used for acquiring the temperature of the first air passage control part and is electrically connected with the heating part; the heat preservation piece is sleeved outside the first air passage control piece.

7. The gas dilution apparatus of claim 1, wherein the second gas circuit control member is a two-position, three-way valve, a first port of the two-position, three-way valve being in communication with the second gas outlet pipe, a second port of the two-position, three-way valve being in communication with the third gas outlet pipe, and a third port of the two-position, three-way valve being in communication with the gas outlet pipe; the two-position three-way valve is provided with a first working state and a second working state, when the two-position three-way valve works in the first working state, a first port of the two-position three-way valve is communicated with a second port, and when the two-position three-way valve works in the second working state, the first port of the two-position three-way valve is communicated with a third port.

8. The gas dilution device according to claim 1, further comprising a detection tube having one end closed, wherein the other end of the detection tube is connected to the gas outlet end of the third gas outlet tube in the leak detection state.

9. The gas dilution apparatus of claim 1, wherein the gas flow controller is connected to the first gas outlet conduit by a sealed joint; the gas flow controller is connected with the second gas outlet pipe through a sealing joint; and the third air outlet pipe is connected with the mixing tank through a sealing joint.

10. The gas dilution apparatus of any one of claims 1 to 9, wherein the first, second, third and vent pipes are passivated pipes.

11. A gas dilution method using the gas dilution apparatus according to any one of claims 1 to 10, comprising the steps of:

a step of introducing diluent gas, wherein the first gas path control part controls the first gas inlet pipe to be communicated with the first gas outlet pipe, the second gas path control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, and diluent gas with a first preset amount is introduced into the mixing tank;

and in the step of introducing high-concentration standard gas, the first gas circuit control part controls the second gas inlet pipe to be communicated with the first gas outlet pipe, the second gas circuit control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, and the second preset amount of high-concentration standard gas is introduced into the mixing tank.

12. The gas dilution method of claim 11, further comprising the step of leak detection: providing a detection tube with one closed end, connecting the other end of the detection tube with the air outlet end of a third air outlet tube, controlling the first air inlet tube to be communicated with the first air outlet tube by a first air circuit control piece, and controlling the second air outlet tube to be communicated with the third air outlet tube by a second air circuit control piece; the third preset amount of diluent gas is firstly introduced into the detection pipe, and then whether gas leakage exists or not is judged according to the pressure change amount detected by the pressure detector within the preset time.

13. The gas dilution method according to claim 11, further comprising a rinsing step before the step of introducing the dilution gas and the step of introducing the standard gas having a high concentration, the rinsing step comprising:

the first gas inlet pipe is used for sequentially feeding a first set amount of diluent gas into the first gas path control part, the first gas outlet pipe, the gas flow controller, the second gas outlet pipe, the second gas path control part and the exhaust pipe, and the diluent gas is discharged outwards through the exhaust pipe;

then the first gas path control part controls the second gas inlet pipe to be communicated with the first gas outlet pipe, and the second gas inlet pipe sends a second set amount of high-concentration standard gas into the first gas path control part, the first gas outlet pipe, the gas flow controller, the second gas outlet pipe, the second gas path control part and the exhaust pipe in sequence and discharges the gas outwards through the exhaust pipe;

then the first air inlet pipe is controlled by the first air path control part to be communicated with the first air outlet pipe, and the first air inlet pipe sends the diluent gas with a third set amount into the first air path control part, the first air outlet pipe, the gas flow controller, the second air outlet pipe, the second air path control part and the exhaust pipe in sequence and is discharged outwards by the exhaust pipe.

14. The method of claim 11, wherein the step of introducing the first predetermined amount of diluent gas into the mixing tank comprises:

firstly, a part of diluent gas in a first preset amount is led into a mixing tank through a first gas inlet pipe, a first gas outlet pipe, a second gas circuit control part and a third gas outlet pipe in sequence, then, high-concentration standard gas in a second preset amount is led into the mixing tank through the second gas inlet pipe, the first gas outlet pipe, the second gas circuit control part and the third gas outlet pipe in sequence, and then, the rest diluent gas in the first preset amount is led into the mixing tank through the first gas inlet pipe, the first gas outlet pipe, the second gas outlet pipe, a second control part gas circuit and the third gas outlet pipe in sequence.

15. The method of claim 11, wherein the method of determining whether the predetermined amount of diluent gas is introduced into the mixing tank comprises:

after the diluent gas is introduced into the mixing tank, controlling the gas flow controller to stop introducing the diluent gas when the pressure detected by the pressure detector reaches a first target value;

judging that the change amount of the pressure detected by the pressure detector exceeds a first preset range within second preset time when the introduction of the diluent gas is stopped, and controlling the gas flow controller to continuously introduce the diluent gas into the mixing tank;

and when the change amount of the pressure detected by the pressure detector does not exceed the first preset range within the second preset time of stopping introducing the diluent gas, indicating that the diluent gas with the preset amount is introduced into the mixing tank.

16. The method of claim 11, wherein when two or more high-concentration standard gases are diluted and mixed with the diluent gas, the step of introducing the high-concentration standard gases comprises: and sequentially introducing more than two standard gases with high concentration into the mixing tank.

Technical Field

The invention relates to the technical field of gas dilution, in particular to a gas dilution device and a gas dilution method.

Background

Conventionally, a standard gas is sold in the market, and when a standard gas with a lower concentration is used, the standard gas with a high concentration is diluted to obtain the standard gas. The current gas dilution instrument generally uses a flow meter to control flow to dilute high-concentration standard gas to obtain lower-concentration standard gas, however, the accuracy of the lower-concentration standard gas obtained by the current gas dilution instrument is not high, and the accurate quantitative requirement in experimental operation cannot be completely met.

Disclosure of Invention

In view of the foregoing, there is a need to overcome the drawbacks of the prior art and to provide a gas dilution apparatus and method that can improve the dilution accuracy of the gas.

The technical scheme is as follows: a gas dilution apparatus, the gas dilution apparatus comprising: the gas path control part is used for controlling one pipeline in the first gas inlet pipe and the second gas inlet pipe to be communicated with the first gas outlet pipe and controlling the rest pipelines in the first gas inlet pipe and the second gas inlet pipe to be disconnected with the first gas outlet pipe, the first gas inlet pipe is used for introducing diluent gas, and the second gas inlet pipe is used for introducing high-concentration standard gas; the gas inlet end of the gas flow controller is communicated with the first gas outlet pipe, and the gas outlet end of the gas flow controller is communicated with the second gas outlet pipe; the second gas path control part is used for controlling the second gas outlet pipe to be communicated with the third gas outlet pipe or the exhaust pipe, the third gas outlet pipe is used for being communicated with the gas inlet end of the mixing tank, and the pressure detector is arranged on the second gas outlet pipe or the third gas outlet pipe.

In the gas diluting device, when the high-concentration standard gas needs to be diluted, the first gas circuit control part controls the first gas inlet pipe to be communicated with the first gas outlet pipe, and the second gas circuit control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, so that the diluted gas can be introduced into the mixing tank; in addition, the first air path control part controls the second air inlet pipe to be communicated with the first air outlet pipe, and the second air path control part controls the second air outlet pipe to be communicated with the third air outlet pipe, so that high-concentration standard gas can be introduced into the mixing tank; under the action of the flow controller and the pressure detector, quantitative diluent gas and quantitative standard gas can be introduced into the mixing tank to be mixed to obtain the standard gas with preset concentration.

In addition, because the gas diluting device comprises the second gas path control part and the exhaust pipe, the second gas path control part can control the second exhaust pipe to be communicated with the exhaust pipe, namely, the rinsing step can be carried out before the diluting step, and the diluting precision of the high-concentration standard gas is improved through the rinsing step.

In one embodiment, the number of the second intake pipes is two or more.

In one embodiment, the gas dilution device further comprises a third gas inlet pipe, and the first gas path control part is used for controlling one of the first gas inlet pipe, the second gas inlet pipe and the third gas inlet pipe to be communicated with the first gas outlet pipe and controlling the rest of the first gas inlet pipe, the second gas inlet pipe and the third gas inlet pipe to be disconnected with the first gas outlet pipe.

In one embodiment, the first gas circuit control is a multi-position switching multi-way valve; the multi-position switching multi-way valve is provided with a first connector, a second connector and an air outlet, the first connector is communicated with the first air inlet pipe, the second connector is communicated with the second air inlet pipe, and the air outlet is communicated with the first air outlet pipe; the multi-position switching multi-way valve can be used for controlling one of the first interface and the second interface to be communicated with the air outlet and controlling the rest interfaces of the first interface and the second interface to be disconnected with the air outlet.

In one embodiment, the gas dilution device further comprises a heating element for heat treating the first gas flow control member.

In one embodiment, the gas dilution device further comprises a temperature measuring part and a heat preservation part; the temperature measuring part is used for acquiring the temperature of the first air passage control part and is electrically connected with the heating part; the heat preservation piece is sleeved outside the first air passage control piece.

In one embodiment, the second gas path control member is a two-position three-way valve, a first port of the two-position three-way valve is communicated with the second gas outlet pipe, a second port of the two-position three-way valve is communicated with the third gas outlet pipe, and a third port of the two-position three-way valve is communicated with the gas exhaust pipe; the two-position three-way valve is provided with a first working state and a second working state, when the two-position three-way valve works in the first working state, a first port of the two-position three-way valve is communicated with a second port, and when the two-position three-way valve works in the second working state, the first port of the two-position three-way valve is communicated with a third port.

In one embodiment, the gas dilution device further comprises a detection pipe with one closed end, and the other end of the detection pipe is connected with the gas outlet end of the third gas outlet pipe in a leak detection state.

In one embodiment, the gas flow controller is connected with the first gas outlet pipe through a sealing joint; the gas flow controller is connected with the second gas outlet pipe through a sealing joint; and the third air outlet pipe is connected with the mixing tank through a sealing joint.

In one embodiment, the first outlet pipe, the second outlet pipe, the third outlet pipe and the exhaust pipe are passivation pipes.

A gas dilution method adopts the gas dilution device and comprises the following steps:

a step of introducing diluent gas, wherein the first gas path control part controls the first gas inlet pipe to be communicated with the first gas outlet pipe, the second gas path control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, and diluent gas with a first preset amount is introduced into the mixing tank;

and in the step of introducing high-concentration standard gas, the first gas circuit control part controls the second gas inlet pipe to be communicated with the first gas outlet pipe, the second gas circuit control part controls the second gas outlet pipe to be communicated with the third gas outlet pipe, and the second preset amount of high-concentration standard gas is introduced into the mixing tank.

According to the gas dilution method, under the action of the gas flow controller and the pressure detector, quantitative diluent gas and quantitative standard gas can be introduced into the mixing tank to be mixed to obtain the standard gas with the preset concentration. In addition, because the gas diluting device comprises the second gas path control part and the exhaust pipe, the second gas path control part can control the second exhaust pipe to be communicated with the exhaust pipe, namely, the rinsing step can be carried out before the diluting step, and the diluting precision of the high-concentration standard gas is improved through the rinsing step.

In one embodiment, the gas dilution method further includes the step of leak detection: providing a detection tube with one closed end, connecting the other end of the detection tube with the air outlet end of a third air outlet tube, controlling the first air inlet tube to be communicated with the first air outlet tube by a first air circuit control piece, and controlling the second air outlet tube to be communicated with the third air outlet tube by a second air circuit control piece; the third preset amount of diluent gas is firstly introduced into the detection pipe, and then whether gas leakage exists or not is judged according to the pressure change amount detected by the pressure detector within the preset time.

In one embodiment, a rinsing step is further included before the step of introducing the dilution gas and the step of introducing the high-concentration standard gas, and the rinsing step includes: the first gas inlet pipe is used for sequentially feeding a first set amount of diluent gas into the first gas path control part, the first gas outlet pipe, the gas flow controller, the second gas outlet pipe, the second gas path control part and the exhaust pipe, and the diluent gas is discharged outwards through the exhaust pipe; then the first gas path control part controls the second gas inlet pipe to be communicated with the first gas outlet pipe, and the second gas inlet pipe sends a second set amount of high-concentration standard gas into the first gas path control part, the first gas outlet pipe, the gas flow controller, the second gas outlet pipe, the second gas path control part and the exhaust pipe in sequence and discharges the gas outwards through the exhaust pipe; then the first air inlet pipe is controlled by the first air path control part to be communicated with the first air outlet pipe, and the first air inlet pipe sends the diluent gas with a third set amount into the first air path control part, the first air outlet pipe, the gas flow controller, the second air outlet pipe, the second air path control part and the exhaust pipe in sequence and is discharged outwards by the exhaust pipe.

In one embodiment, the method of introducing a first predetermined amount of diluent gas into the mixing tank comprises: firstly, a part of diluent gas in a first preset amount is led into a mixing tank through a first gas inlet pipe, a first gas outlet pipe, a second gas circuit control part and a third gas outlet pipe in sequence, then, high-concentration standard gas in a second preset amount is led into the mixing tank through the second gas inlet pipe, the first gas outlet pipe, the second gas circuit control part and the third gas outlet pipe in sequence, and then, the rest diluent gas in the first preset amount is led into the mixing tank through the first gas inlet pipe, the first gas outlet pipe, the second gas outlet pipe, a second control part gas circuit and the third gas outlet pipe in sequence.

In one embodiment, the method for determining whether a predetermined amount of diluent gas is introduced into the mixing tank includes: after the diluent gas is introduced into the mixing tank, controlling the gas flow controller to stop introducing the diluent gas when the pressure detected by the pressure detector reaches a first target value; judging that the change amount of the pressure detected by the pressure detector exceeds a first preset range within second preset time when the introduction of the diluent gas is stopped, and controlling the gas flow controller to continuously introduce the diluent gas into the mixing tank; and when the change amount of the pressure detected by the pressure detector does not exceed the first preset range within the second preset time of stopping introducing the diluent gas, indicating that the diluent gas with the preset amount is introduced into the mixing tank.

In one embodiment, when two or more high-concentration standard gases are required to be diluted and mixed with the diluent gas, the step of introducing the high-concentration standard gases specifically comprises the following steps: and sequentially introducing more than two standard gases with high concentration into the mixing tank.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a gas dilution device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an embodiment of a gas dilution device according to the present invention in one of its operating states;

FIG. 3 is a schematic view of another operation state of the gas dilution device according to an embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating another operation state of the gas dilution device according to an embodiment of the present invention.

10. A first air passage control member; a1, a first interface; a2, a second interface; a3, a third interface; a4, an air outlet; 21. a first intake pipe; 22. a second intake pipe; 23. a third intake pipe; 24. a first air outlet pipe; 30. a gas flow controller; 40. a second air outlet pipe; 50. a second gas path control member; b1, first port; b2, a second port; b3, third port; 60. a third air outlet pipe; 70. an exhaust pipe; 80. a pressure detector; 91. a heating member; 92. a temperature measuring part; 93. a detection tube; 94. and (4) mixing the materials in a tank.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Referring to fig. 1, fig. 1 shows a schematic structural diagram of a gas dilution device according to an embodiment of the present invention, and the gas dilution device according to an embodiment of the present invention includes a first gas path control component 10, a first gas inlet pipe 21, a second gas inlet pipe 22, a first gas outlet pipe 24, a gas flow controller 30, a second gas outlet pipe 40, a second gas path control component 50, a third gas outlet pipe 60, a gas outlet pipe 70, and a pressure detector 80.

The first air passage control member 10 is used for controlling one of the first and second air inlet pipes 21 and 22 to be communicated with the first air outlet pipe 24, and for controlling the rest of the first and second air inlet pipes 21 and 22 to be disconnected from the first air outlet pipe 24. The first inlet pipe 21 is used for introducing dilution gas, and the second inlet pipe 22 is used for introducing standard gas with high concentration. The gas inlet end of the gas flow controller 30 is communicated with the first gas outlet pipe 24, and the gas outlet end of the gas flow controller 30 is communicated with the second gas outlet pipe 40. The second air path control member 50 is used to control the second outlet duct 40 to communicate with the third outlet duct 60 or the exhaust duct 70, and the third outlet duct 60 is used to communicate with the air inlet end of the mixing tank 94. The pressure detector 80 is disposed on the second outlet duct 40 or the third outlet duct 60.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating an operating state of the gas dilution device according to an embodiment of the present invention, when a high-concentration standard gas needs to be diluted, the first gas path control member 10 controls the first gas inlet tube 21 to be communicated with the first gas outlet tube 24, and the second gas path control member 50 controls the second gas outlet tube 40 to be communicated with the third gas outlet tube 60, so that the diluted gas can be introduced into the mixing tank 94; in addition, the first air path control part 10 controls the second air inlet pipe 22 to be communicated with the first air outlet pipe 24, and the second air path control part 50 controls the second air outlet pipe 40 to be communicated with the third air outlet pipe 60, so that high-concentration standard gas can be introduced into the mixing tank 94; under the action of the flow controller and the pressure detector 80, a certain amount of diluent gas and a certain amount of standard gas can be introduced into the mixing tank 94 to be mixed to obtain a standard gas with a preset concentration.

In addition, referring to fig. 3, fig. 3 is a schematic view illustrating another working state of the gas dilution device according to an embodiment of the present invention, because the gas dilution device includes the second gas path control member 50 and the exhaust pipe 70, the second gas path control member 50 can control the second exhaust pipe 40 to communicate with the exhaust pipe 70, that is, a rinsing step can be performed before the dilution step, and the dilution precision of the high-concentration standard gas can be improved by the rinsing step.

Referring to fig. 3, the rinsing steps in an embodiment may be:

the first air path control part 10 controls the first air inlet pipe 21 to be communicated with the first air outlet pipe 24, the second air path control part 50 controls the second air outlet pipe 40 to be communicated with the exhaust pipe 70, the first air inlet pipe 21 sequentially sends a certain amount of diluent gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70, the diluent gas is discharged outwards through the exhaust pipe 70, and the diluent gas can be discharged completely in the pipeline in the process of flowing through the first air outlet pipe 24, the gas flow controller 30 and the second air outlet pipe 40, so that a cleaning effect is achieved;

then the first gas path control part 10 controls the second gas inlet pipe 22 to be communicated with the first gas outlet pipe 24, the second gas inlet pipe 22 sends a certain amount of high-concentration standard gas into the first gas path control part 10, the first gas outlet pipe 24, the gas flow controller 30, the second gas outlet pipe 40, the second gas path control part 50 and the exhaust pipe 70 in sequence, the high-concentration standard gas is discharged outwards through the exhaust pipe 70, and the walls of all the pipelines are rinsed by the high-concentration standard gas so as to improve the subsequent dilution precision;

then the first air inlet pipe 21 is controlled by the first air path control part 10 to be communicated with the first air outlet pipe 24, a certain amount of diluent gas is sequentially sent into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 by the first air inlet pipe 21 and is discharged outwards by the exhaust pipe 70, and standard gas in each pipeline can be discharged outwards.

Note that the diluent gas is, for example, nitrogen, dry air, helium, other rare gas, or the like. Specifically, in the present embodiment, the diluent gas is, for example, nitrogen.

In one embodiment, there are more than two second intake pipes 22. In this way, two or more second intake pipes 22 may be used to correspondingly introduce two or more standard gases with high concentrations, so that respective mixing of the standard gases with different high concentrations, or mutual mixing, can be realized. And when the specific work is performed, as an example, when the first air path control part 10 controls one of the more than two second air inlet pipes 22 to be communicated with the first air outlet pipe 24, the high-concentration standard gas in the second air inlet pipe 22 can be correspondingly sent to the first air outlet pipe 24, and at this time, the rest of the second air inlet pipes 22 are all in a cut-off state and are not communicated with the first air outlet pipe 24.

Referring to any one of fig. 1 to 3, in one embodiment, the gas dilution device further includes a third gas inlet pipe 23. The first air passage control member 10 is used for controlling one of the first air inlet pipe 21, the second air inlet pipe 22 and the third air inlet pipe 23 to be communicated with the first air outlet pipe 24, and for controlling the rest of the first air inlet pipe 21, the second air inlet pipe 22 and the third air inlet pipe 23 to be disconnected from the first air outlet pipe 24.

It should be noted that when the first air passage control member 10 controls one of the first air inlet pipe 21, the second air inlet pipe 22 and the third air inlet pipe 23 to be communicated with the first air outlet pipe 24, the rest of the first air inlet pipe 21, the second air inlet pipe 22 and the third air inlet pipe 23 are disconnected from the first air outlet pipe 24. For example, when the first air channel control member 10 controls the first air inlet pipe 21 to be communicated with the first air outlet pipe 24, the second air inlet pipe 22 and the third air inlet pipe 23 are not communicated with the first air outlet pipe 24, and both the second air inlet pipe 22 and the third air inlet pipe 23 are in a stop state; for another example, when the first air channel control component 10 controls the second air inlet pipe 22 to be communicated with the first air outlet pipe 24, the first air inlet pipe 21 and the third air inlet pipe 23 are not communicated with the first air outlet pipe 24, and the first air inlet pipe 21 and the third air inlet pipe 23 are both in a cut-off state.

Referring to fig. 2 and 3, in one embodiment, the first air channel control member 10 is a multi-position switching multi-way valve. The multi-position switching multi-way valve is provided with a first connector A1, a second connector A2 and an air outlet A4, the first connector A1 is communicated with a first air inlet pipe 21, the second connector A2 is communicated with a second air inlet pipe 22, and the air outlet A4 is communicated with a first air outlet pipe 24; the multi-position switching multi-way valve can be used for controlling one of the first port A1 and the second port A2 to be communicated with the air outlet A4, and controlling the rest of the first port A1 and the second port A2 to be disconnected with the air outlet A4. Thus, when the multi-position switching multi-way valve controls the first port a1 to be communicated with the gas outlet a4, the first gas inlet pipe 21 is communicated with the first gas outlet pipe 24, so that the diluent gas in the first gas inlet pipe 21 can be introduced, at the moment, the second port a2 is in a cut-off state and is not communicated with the gas outlet a4, namely, the second gas inlet pipe 22 does not introduce the high-concentration standard gas into the first gas outlet pipe 24 in the working state; similarly, when the multi-position switching multi-way valve controls the second port a2 to be communicated with the gas outlet a4, the second gas inlet pipe 22 is communicated with the first gas outlet pipe 24, so that the high-concentration standard gas in the second gas inlet pipe 22 can be introduced, and at the moment, the first port a1 is in a cut-off state and is not communicated with the gas outlet a4, that is, the first gas inlet pipe 21 does not introduce the diluent gas into the first gas outlet pipe 24 in the working state.

Referring to fig. 2 and 3, in order to connect two or more second air inlet pipes 22, there may be more than one second port a2 of the multi-position switching multi-way valve, for example, there may be two or more second ports a2, and at this time, two or more second air inlet pipes 22 may be correspondingly installed on the two or more second ports a 2. For example, the number of the second ports a2 illustrated in this embodiment is specifically 4, so that 4 kinds of high-concentration standard gases can be correspondingly introduced.

Referring to fig. 2 and 3, in order to connect the third air inlet pipe 23, the multi-position switching multi-way valve further includes a third port A3, and the third port A3 is used for communicating with the third air inlet pipe 23. The multi-position switching multi-way valve can control one of the first interface A1, the second interface A2 and the third interface A3 to be communicated with the air outlet A4, and is used for controlling the rest of the first interface A1, the second interface A2 and the third interface A3 to be disconnected with the air outlet A4.

Optionally, the first air passage control member 10 is not limited to a multi-position switching multi-way valve, and may also include a plurality of control switches, and the control switches are respectively disposed on the first air inlet pipe 21, the second air inlet pipe 22, and the third air inlet pipe 23, and the control switch on one of the first air inlet pipe 21, the second air inlet pipe 22, and the third air inlet pipe 23 is turned on, and the control switches on the other pipes are turned off, so that one of the first air inlet pipe 21, the second air inlet pipe 22, and the third air inlet pipe 23 may be controlled to be communicated with the first air outlet pipe 24.

In one embodiment, the gas dilution device further includes a heating member 91 for heat-treating the first gas flow control member 10. Thus, the first air passage control member 10 is heated by the heating member 91, so that the adsorption of the tube wall of the first air passage control member 10 to the standard gas can be reduced as much as possible, and the dilution precision of the standard gas can be improved. Specifically, the heating member 91 is not limited in structure, and may be, for example, a heating wire wound around an outer wall of the first air-path control member 10, a heating wire disposed on an inner wall of the first air-path control member 10, a semiconductor for transferring generated heat to the first air-path control member 10, or the like.

In one embodiment, the gas dilution device further comprises a temperature measurement member 92 and a temperature keeping member (not shown). The temperature measuring member 92 is used for acquiring the temperature of the first air passage control member 10, and the temperature measuring member 92 is electrically connected to the heating member 91. The insulating member is fitted to the outside of the first air passage control member 10. Therefore, the temperature of the first air passage control member 10 is sensed by the temperature measuring member 92, and whether the heating member 91 is heated or not is correspondingly controlled, so that the temperature of the first air passage control member 10 can be well controlled within a preset range.

Specifically, the heat insulating member includes heat insulating cotton, quartz fiber cloth, nano felt, or other heat insulating material wound around the outer wall of the first air passage control member 10. In addition, the heat insulating member may also include a heat insulating cover covering the outer wall of the first air passage control member 10. Of course, the heat-insulating member may also include a heat-insulating cotton wound around the outer wall of the first air passage control member 10, and a heat-insulating cover covering the first air passage control member 10, so as to achieve a good heat-insulating effect on the first air passage control member 10.

Alternatively, it is not necessary to provide the heating member 91, the temperature measuring member 92, and the heat insulating member on the first gas passage control member 10, but a passivated metal member may be used as the first gas passage control member 10, and thus the passivated metal member also has a low adsorption capacity for the standard gas, so that the amount of the standard gas adsorbed on the inner wall of the first gas passage control member 10 can be reduced as much as possible, and the dilution accuracy of the standard gas can be improved.

Referring to fig. 2 and 3, in one embodiment, the second air path control member 50 is a two-position three-way valve, a first port B1 of the two-position three-way valve is communicated with the second outlet pipe 40, a second port B2 of the two-position three-way valve is communicated with the third outlet pipe 60, and a third port B3 of the two-position three-way valve is communicated with the exhaust pipe 70. The two-position three-way valve is provided with a first working state and a second working state, when the two-position three-way valve works in the first working state, the first port B1 of the two-position three-way valve is communicated with the second port B2, and when the two-position three-way valve works in the second working state, the first port B1 of the two-position three-way valve is communicated with the third port B3.

Specifically, the two-position three-way valve is, for example, a two-position three-way solenoid valve or a two-position three-way pneumatic valve, so that the second outlet pipe 40 can be automatically controlled to be communicated with the third outlet pipe 60, or the second outlet pipe 40 can be controlled to be communicated with the exhaust pipe 70, manual operation is not needed, and the working efficiency is high.

It is to be understood that the second air path control member 50 is not limited to the two-position three-way valve, and for example, a three-way valve may be used to connect the outlet end of the second outlet pipe 40, the inlet end of the third outlet pipe 60 and the inlet end of the exhaust pipe 70 to each other, and switch valves may be respectively disposed on the second outlet pipe 40, the third outlet pipe 60 and the exhaust pipe 70 instead of the two-position three-way valve.

Referring to fig. 4, fig. 4 is a schematic view illustrating another working state of the gas dilution device according to an embodiment of the present invention, in which the gas dilution device further includes a detection tube 93 with one end closed. In a leak detection state, the other end of the detection tube 93 is connected to the outlet end of the third outlet tube 60.

In one embodiment, the gas flow controller 30 is connected to the first outlet conduit 24 by a sealed joint (not shown). The gas flow controller 30 is connected to the second gas outlet pipe 40 by a sealing joint. The third outlet duct 60 is connected to the mixing tank 94 by a sealed joint.

In addition, the first port a1 is connected with the first air inlet pipe 21 through a sealing joint, the second port a2 is connected with the second air inlet pipe 22 through a sealing joint, the third port A3 is connected with the third air inlet pipe 23 through a sealing joint, and the air outlet a4 is connected with the first air outlet pipe 24 through a sealing joint. In addition, the first port B1 is connected to the second outlet duct 40 by a sealing joint, the second port B2 is connected to the third outlet duct 60 by a sealing joint, and the third port B3 is connected to the exhaust duct 70 by a sealing joint.

In one embodiment, the first outlet duct 24, the second outlet duct 40, the third outlet duct 60, and the exhaust duct 70 are passivated ducts.

Referring to fig. 2, in one embodiment, a gas dilution method using the gas dilution apparatus of any one of the above embodiments includes the following steps:

step S100, a step of introducing diluent gas, wherein the first gas path control part 10 controls the first gas inlet pipe 21 to be communicated with the first gas outlet pipe 24, the second gas path control part 50 controls the second gas outlet pipe 40 to be communicated with the third gas outlet pipe 60, and a first preset amount of diluent gas is introduced into the mixing tank 94;

step S200, a step of introducing high-concentration standard gas, wherein the first gas path control part 10 controls the second gas inlet pipe 22 to be communicated with the first gas outlet pipe 24, the second gas path control part 50 controls the second gas outlet pipe 40 to be communicated with the third gas outlet pipe 60, and a second preset amount of high-concentration standard gas is introduced into the mixing tank 94.

In the gas dilution method, under the action of the gas flow controller 30 and the pressure detector 80, a certain amount of diluent gas and a certain amount of standard gas can be introduced into the mixing tank 94 to be mixed to obtain the standard gas with the preset concentration. In addition, since the gas dilution device includes the second gas path control member 50 and the exhaust pipe 70, the second gas path control member 50 can control the second gas outlet pipe 40 to communicate with the exhaust pipe 70, that is, the rinsing step S50 can be performed before the dilution step, and the dilution accuracy of the high-concentration standard gas can be improved by the rinsing step S50.

Optionally, the order of the step of introducing the diluent gas and the step of introducing the high-concentration standard gas is not limited, and the step of introducing the diluent gas may be performed first, and then the step of introducing the high-concentration standard gas may be performed; or the step of introducing high-concentration standard gas can be carried out firstly, and then the step of introducing diluent gas is carried out; it is also possible to perform the step of introducing the diluent gas first, then perform the step of introducing the high-concentration standard gas, then perform the step of introducing the diluent gas, and so on.

Further, the gas dilution method further comprises a leak detection step S20:

step S21, providing a detection tube 93 with one end closed, connecting the other end of the detection tube 93 with the air outlet end of the third air outlet tube 60, controlling the first air inlet tube 21 to be communicated with the first air outlet tube 24 by the first air path control part 10, and controlling the second air outlet tube 40 to be communicated with the third air outlet tube 60 by the second air path control part 50;

step S22, first, a third preset amount of diluent gas is introduced into the detection tube 93, and then, whether there is an air leak is determined according to the pressure change detected by the pressure detector 80 within a preset time. Therefore, when the branch formed by the third air outlet pipe 60, the second air path control element 50 and the second air outlet pipe 40 is judged to have air leakage according to the pressure change detected by the pressure detector 80, the third air outlet pipe 60, the second air path control element 50 and the second air outlet pipe 40 are maintained in time, the sealing performance of the branch formed by the third air outlet pipe 60, the second air path control element 50 and the second air outlet pipe 40 is improved, and the dilution precision of the standard gas can be improved.

Specifically, when the pressure change amount within the preset time exceeds a preset value, the existence of air leakage is correspondingly judged, and the sealing performance is poor; when the pressure change amount in the preset time does not exceed the preset value, air leakage does not exist according to corresponding judgment, and the sealing performance is good.

Specifically, the third preset amount is set according to actual requirements, and is not limited herein. The preset time and the pressure change amount are also set according to actual requirements, and are not limited herein.

In this embodiment, the leak detection step is performed before the step of introducing the diluent gas and the step of introducing the standard gas having a high concentration. Of course, the leak detection step may be performed after the step of introducing the diluent gas and the step of introducing the standard gas with a high concentration, and the embodiment is not limited herein.

In one embodiment, a rinsing step S50 is further included before the step S100 of introducing the dilution gas and the step S200 of introducing the high-concentration standard gas, and the rinsing step S50 includes:

s51, controlling a first air inlet pipe 21 to be communicated with a first air outlet pipe 24 through a first air path control part 10, controlling a second air outlet pipe 40 to be communicated with an air outlet pipe 70 through a second air path control part 50, and sequentially sending a first set amount of diluent gas into the first air path control part 10, the first air outlet pipe 24, a gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the air outlet pipe 70 through the first air inlet pipe 21 and discharging the diluent gas outwards through the air outlet pipe 70;

therefore, the diluent gas can be exhausted in the pipeline in the process of flowing through the first gas outlet pipe 24, the gas flow controller 30 and the second gas outlet pipe 40, and the cleaning effect is achieved;

s52, controlling the second air inlet pipe 22 to be communicated with the first air outlet pipe 24 by the first air path control part 10, sending a second set amount of high-concentration standard gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 in sequence by the second air inlet pipe 22, and discharging the gas outwards by the exhaust pipe 70;

therefore, when high-concentration standard gas flows through the first gas path control element 10, the first gas outlet pipe 24, the gas flow controller 30, the second gas outlet pipe 40, the second gas path control element 50 and the exhaust pipe 70, the pipe wall of each pipeline can be rinsed, so that the subsequent dilution precision is improved.

S53, controlling the first air inlet pipe 21 to be communicated with the first air outlet pipe 24 by the first air path control element 10, and sending the third setting amount of the diluent gas into the first air path control element 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control element 50 and the exhaust pipe 70 in sequence by the first air inlet pipe 21, and discharging the diluent gas from the exhaust pipe 70.

Thus, the diluent gas flows through the first gas path control member 10, the first gas outlet pipe 24, the gas flow controller 30, the second gas outlet pipe 40, the second gas path control member 50 and the gas outlet pipe 70 in sequence, so that the standard gas in each pipeline can be discharged outwards.

Further, the method of introducing the first predetermined amount of the diluent gas into the mixing tank 94 includes:

step S110, firstly, introducing a part of the diluent gas in a first preset amount into the mixing tank 94 through the first gas inlet pipe 21, the first gas outlet pipe 24, the second gas outlet pipe 40, the second gas path control part 50 and the third gas outlet pipe 60 in sequence;

step S120, then, introducing a second preset amount of high-concentration standard gas into the mixing tank 94 through the second gas inlet pipe 22, the first gas outlet pipe 24, the second gas outlet pipe 40, the second gas path control part 50 and the third gas outlet pipe 60 in sequence;

step S130, the rest of the diluent gas with the first preset amount is introduced into the mixing tank 94 sequentially through the first gas inlet pipe 21, the first gas outlet pipe 24, the second gas outlet pipe 40, the second gas path control member 50 and the third gas outlet pipe 60.

Thus, the mixing tank 94 is generally a vacuum tank, and since a part of the diluent gas is introduced into the mixing tank 94 first, the mixing tank 94 has a certain pressure, and then when the second preset amount of the high-concentration standard gas is introduced into the mixing tank 94 to be mixed with the diluent gas, since the mixing tank 94 has a certain pressure, even if the second preset amount is usually small, the second preset amount can be conveniently and accurately introduced into the mixing tank 94, thereby improving the dilution accuracy.

For example, the first predetermined amount is 20 moles and the second predetermined amount is 2 moles, and for example, 5 moles of the diluent gas are introduced into the mixing tank 94, then 2 moles of the standard gas are introduced into the mixing tank 94, and then the remaining 15 moles of the diluent gas are introduced into the mixing tank 94.

Specifically, in step S100, when a part of the diluent gas in the first preset amount is introduced into the mixing tank 94, whether the requirement is met is determined by the first pressure detected by the pressure detector 80, for example, whether the first pressure reaches 12 PSI is determined, and when the first pressure reaches 12 PSI, it indicates that the first introduced amount of the diluent gas meets the requirement; then, a second preset amount of high-concentration standard gas is introduced into the mixing tank 94, whether the requirement is met is judged through a second pressure detected by the pressure detector 80, for example, whether the second pressure reaches 14 PSI is judged, and when the second pressure reaches 14 PSI, the introduction of the high-concentration standard gas is indicated to meet the requirement; then, the diluent gas of the remaining part of the first preset amount is introduced into the mixing tank 94, and the third pressure detected by the pressure detector 80 is used for judging whether the requirement is met, for example, whether the third pressure reaches 40 PSI is judged, when the first pressure reaches 40 PSI, the second introduction amount of the diluent gas is indicated to meet the requirement, so that the high-concentration standard gas is diluted to 40 PSI pressure by 2 PSI, namely, the diluent gas is diluted by 20 times.

It should be noted that, after the high-concentration standard gas is introduced into the mixing tank 94 for dilution, the concentration of the standard gas in the mixing tank 94 cannot meet the requirement yet, and if the standard gas in the mixing tank 94 is further diluted, the standard gas in the mixing tank 94 may be connected to the third gas inlet pipe 23, and further dilution is performed according to the manner in the foregoing embodiment, which is not described herein again.

Further, the method for determining whether the preset amount of the diluent gas is introduced into the mixing tank 94 includes:

step S111, after the diluent gas is introduced into the mixing tank 94, controlling the gas flow controller 30 to stop introducing the diluent gas when the pressure detected by the pressure detector 80 reaches a first target value;

step S112, if it is determined that the amount of change in the pressure detected by the pressure detector 80 exceeds the first preset range within the second preset time when the introduction of the diluent gas is stopped, controlling the gas flow controller 30 to continue introducing the diluent gas into the mixing tank 94;

step S113, when it is determined that the amount of change in the pressure detected by the pressure detector 80 does not exceed the first preset range within the second preset time when the introduction of the diluent gas is stopped, indicating that a preset amount of diluent gas is introduced into the mixing tank 94.

Thus, when the pressure detected by the pressure detector 80 reaches the first target value, the gas path needs to be stabilized for a second preset time, and then the relationship between the pressure detected by the pressure detector 80 and the first target value is determined, when the change amount exceeds the first preset range, it indicates that the preset amount of diluent gas is not introduced into the mixing tank 94, and at this time, the preset amount can be reached by further introducing the diluent gas into the mixing tank 94; otherwise, no further diluent gas need be introduced into the mixing tank 94.

Note that the first target value is determined according to a preset amount. In addition, the first preset range, the second preset time and the change amount may be adjusted and set according to actual situations, and are not limited herein.

It should be noted that the method for determining whether the preset amount of the high-concentration standard gas is introduced into the mixing tank 94 is similar to the method for determining whether the preset amount of the diluent gas is introduced into the mixing tank 94, and details thereof are not repeated herein.

Further, when more than two standard gases with high concentration need to be diluted and mixed with the diluent gas, the step of introducing the standard gases with high concentration specifically comprises the following steps: two or more standard gases at high concentrations are sequentially introduced into the mixing tank 94.

Specifically, in the present embodiment, the number of the second gas inlet pipes 22 is two or more, and when two or more high-concentration standard gases and diluent gases need to be diluted and mixed, the first gas path controller 10 controls the two or more second gas inlet pipes 22 to be sequentially communicated with the first gas outlet pipe 24, so that the two or more high-concentration standard gases and the diluent gases can be diluted and mixed, and the dilution precision can be ensured.

Referring to fig. 3, in an embodiment, if two or more high-concentration standard gases are required to be diluted and mixed with the diluent gas, in order to reduce the adsorption amount of the standard gases on the walls of the first outlet pipe 24, the gas flow controller 30, the second outlet pipe 40 and the second gas path control element 50, the rinsing step S50 in the above embodiment specifically includes the following steps:

step S51, firstly, the first air inlet pipe 21 is controlled to be communicated with the first air outlet pipe 24 through the first air path control part 10, the second air outlet pipe 40 is controlled to be communicated with the exhaust pipe 70 through the second air path control part 50, and the first air inlet pipe 21 sends a first set amount of diluent gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 in sequence and is discharged outwards through the exhaust pipe 70;

step S52, controlling one of the second air inlet pipes 22 to be communicated with the first air outlet pipe 24 by the first air path control part 10, sending a second set amount of high-concentration standard gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 in sequence by one of the second air inlet pipes 22, and discharging the gas outwards by the exhaust pipe 70;

step S53, controlling the first air inlet pipe 21 to be communicated with the first air outlet pipe 24 by the first air path control part 10, and sequentially sending a third set amount of diluent gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 by the first air inlet pipe 21 and discharging the diluent gas outwards by the exhaust pipe 70;

step S54, controlling another second air inlet pipe 22 to be communicated with the first air outlet pipe 24 by the first air path control part 10, sending a fourth set amount of high-concentration standard gas into the first air path control part 10, the first air outlet pipe 24, the gas flow controller 30, the second air outlet pipe 40, the second air path control part 50 and the exhaust pipe 70 in sequence by the another second air inlet pipe 22, and discharging the gas outwards by the exhaust pipe 70;

step S55, the first air channel control element 10 controls the first air inlet tube 21 to communicate with the first air outlet tube 24, and the first air inlet tube 21 sequentially sends the third amount of diluent gas into the first air channel control element 10, the first air outlet tube 24, the gas flow controller 30, the second air outlet tube 40, the second air channel control element 50 and the exhaust tube 70, and the diluent gas is discharged from the exhaust tube 70. Thus, steps S54 and S55 are repeated until more than two high concentration standard gases are introduced into the first gas path controller 10, the first gas outlet pipe 24, the gas flow controller 30, the second gas outlet pipe 40, the second gas path controller 50 and the exhaust pipe 70 in sequence, and are discharged from the exhaust pipe 70. And after more than two high-concentration standard gases rinse the walls of the first gas path control member 10, the first gas outlet pipe 24, the gas flow controller 30, the second gas outlet pipe 40, the second gas path control member 50 and the exhaust pipe 70, the step S100 of introducing diluent gas is performed.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.