CN214367961U - Gas passage selection device and natural gas detection equipment - Google Patents

Abstract

The utility model relates to a gas passage selection device and natural gas detection equipment, the gas passage selection device comprises a main body and a plurality of on-off valves, an annular gas circuit, a plurality of gas inlet channels, a plurality of first gas outlet channels and a second gas outlet channel are arranged in the main body, the plurality of gas inlet channels are respectively communicated with the plurality of first gas outlet channels in a one-to-one correspondence manner, and the annular gas circuit is communicated between the plurality of first gas outlet channels and the second gas outlet channel; each on-off valve is arranged between one air inlet channel and one first air outlet channel which are communicated. The embodiment of the utility model provides a gas passage selecting arrangement makes gas fall into two parts and flow towards both sides respectively in annular gas circuit through set up annular gas circuit between first gas outlet channel and second gas outlet channel, until joining in second gas outlet channel, from this, remains other gas in inside and can be discharged fast, has improved and has cleaned speed, has solved the problem that the inside residual gas of valves cleaned the time overlength among the prior art.

Description

Gas passage selection device and natural gas detection equipment

Technical Field

The utility model belongs to the technical field of gaseous detection, concretely relates to gas passage selecting arrangement and natural gas check out test set.

Background

This section provides background information related to the present disclosure only and is not necessarily prior art.

In a town gas system, an urban natural gas valve station is a terminal station of a long-distance gas transmission main line, is an important component of a natural gas transmission and distribution system, and has the task of receiving gas transmitted by a long-distance pipeline, purifying, regulating pressure, metering, detecting gas quality and odorizing in the station, and then sending the gas into an urban transmission and distribution pipe network or directly sending the gas into large-scale industrial and commercial users.

Use online gas chromatograph to detect the gas quality of natural gas among the prior art usually, online gas chromatograph can judge gaseous quality and carry out energy measurement, but the pipeline of input gas usually has many in natural gas gate station, if every pipeline uses a natural gas chromatography appearance, can lead to cost-push, consequently, gaseous chromatography appearance usually with four advance a valves intercommunication among the prior art to carry out the analysis of timesharing sample gas to many gas circuits.

However, as shown in fig. 1, when the valve block is switched to detect the gas in the second gas path 2, the gas in the first gas path 1 detected before the switching still remains in the valve block, so that the valve block needs to be ventilated and cleaned for a certain time before the detection, and the dead space 3 exists in the valve block, so that the residual gas is difficult to discharge, the cleaning time is too long, and the gas in the gas path is wasted.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the problem of the overlong time for cleaning residual gas in the valve bank in the prior art at least. The purpose is realized by the following technical scheme:

the utility model discloses a first aspect provides a gas passage selecting arrangement, include:

the gas-liquid separator comprises a main body, wherein an annular gas circuit, a plurality of gas inlet channels, a plurality of first gas outlet channels and a second gas outlet channel are arranged in the main body, the plurality of gas inlet channels are respectively communicated with the plurality of first gas outlet channels in a one-to-one correspondence manner, and the annular gas circuit is communicated between the plurality of first gas outlet channels and the second gas outlet channels;

and each on-off valve is arranged between one air inlet channel and one first air outlet channel which are communicated.

According to the utility model discloses gas passage selecting arrangement, through set up the inlet channel that communicates in proper order in the main part, first outlet channel and second outlet channel, provide the route for the flow of gas, through set up annular gas circuit between first outlet channel and second outlet channel, make the gas that flows by first outlet channel can get into rather than the annular gas circuit of intercommunication, the structure of annular gas circuit makes gas fall into two parts and flow towards both sides respectively, until the second outlet channel who converges and annular gas circuit intercommunication, therefore, remain other gas in inside before the gas inflow and can be discharged fast, the speed of cleaning is improved, the problem of the inside residual gas cleaning time overlength of valves among the prior art has been solved.

In addition, according to the utility model discloses gas passage selection device, can also have following technical characterstic:

in some embodiments of the present invention, the main body includes a first valve plate and a second valve plate connected by a lock, the air inlet channel and the first air outlet channel are respectively disposed through the first valve plate and the second valve plate, the annular air channel is formed on the first valve plate and/or the second valve plate, and the second air outlet channel is disposed in the first valve plate or the second valve plate.

In some embodiments of the present invention, the air intake passage includes a plurality of first air vents formed in the first valve plate and a plurality of second air vents formed in the second valve plate, and both ends of the second air vents communicate with the first air vents and the air intake end of the on-off valve, respectively.

In some embodiments of the present invention, the first air outlet channel and the annular air channel are disposed on the second valve plate, and the second air outlet channel is disposed on the first valve plate.

In some embodiments of the present invention, the first valve plate is provided with a plurality of air inlets and a plurality of air outlets, the air inlets are communicated with the first air vents in a one-to-one correspondence, and the air outlets are communicated with the second air outlet channel.

In some embodiments of the present invention, the gas pathway selection device further comprises a plurality of cutting sleeves, the cutting sleeves being connected in each of the gas inlet and the gas outlet by cutting sleeve screws.

In some embodiments of the present invention, the second valve plate faces one side of the first valve plate and is provided with a groove, and the annular gas circuit is disposed in the groove.

In some embodiments of the utility model, be provided with first sealed pad and the sealed pad of second in the recess, first sealed pad sets up to the annular and is in around setting up the sealed periphery of second, the annular gas circuit forms first sealed pad with between the sealed pad of second.

In some embodiments of the present invention, the first sealing pad has a plurality of through holes, and the through holes are disposed in one-to-one correspondence with the second ventilation holes and coaxially.

In some embodiments of the present invention, the thickness of the first and second sealing gaskets equals the depth of the groove.

In some embodiments of the present invention, a connection post is disposed in the groove, a connection hole is disposed on the second sealing pad, and the connection post is matched with the connection hole.

In some embodiments of the present invention, the number of the inlet channels is four, the number of the first outlet channels is four, and the number of the on-off valves is four.

The utility model discloses the second aspect provides a natural gas detection equipment, natural gas detection equipment includes:

a gas supply device;

an online gas chromatograph;

according to the gas passage selection device provided by any one of the above embodiments, the gas passage selection device is communicated between the gas supply device and the online gas chromatograph.

The utility model provides a natural gas check out test set has the same advantage with the gas passage selecting arrangement in above-mentioned embodiment, no longer gives unnecessary details here.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like parts are designated by like reference numerals throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram of the gas flow in a four-in one-out valve set according to the prior art;

FIG. 2 is a schematic diagram of the gas flow in the gas channel selection device according to the embodiment of the present invention;

fig. 3 is an exploded view of a gas passage selection device according to an embodiment of the present invention;

FIG. 4 is a schematic view of the first and second valve bodies of the gas passage selector apparatus shown in FIG. 3, viewed from below;

FIG. 5 is a schematic structural view of a first valve body in the gas passage selection device shown in FIG. 3;

FIG. 6 is a schematic view showing an internal structure of the first valve body shown in FIG. 5;

FIG. 7 is a schematic view of the second valve body, the first gasket, and the second gasket of the gas passage selection device of FIG. 3 prior to engagement;

FIG. 8 is a top view of the second valve body, the first gasket, and the second gasket shown in FIG. 7 after mating.

The reference symbols in the drawings denote the following:

1. a first gas path; 2. a second gas path; 3. a dead space;

1000. a gas passage selection device;

100. a main body; 101. an air intake passage; 102. an annular gas circuit; 103. a first air outlet channel; 104. a second air outlet channel;

110. a first valve plate; 111. a first vent hole; 112. an air inlet; 113. an air outlet; 114. a first connection hole;

120. a second valve plate; 121. a second vent hole; 122. a groove; 123. connecting columns; 124. a second connection hole;

200. an on-off valve;

300. a card sleeve;

400. clamping the screw;

510. a first gasket; 511. a through hole; 520. a second gasket; 521. connecting holes;

600. and (4) bolts.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 2 to 8, an embodiment of the present invention provides a gas passage selection device 1000, where the gas passage selection device 1000 includes a main body 100 and a plurality of on-off valves 200, an annular gas passage 102, a plurality of gas inlet channels 101, a plurality of first gas outlet channels 103 and a second gas outlet channel 104 are provided in the main body 100, the plurality of gas inlet channels 101 are respectively communicated with the plurality of first gas outlet channels 103 in a one-to-one correspondence manner, and the annular gas passage 102 is communicated between the plurality of first gas outlet channels 103 and the second gas outlet channel 104; each on-off valve 200 is provided between one intake passage 101 and one first exhaust passage 103 that communicate.

The embodiment of the utility model provides a gas passage selecting arrangement 1000, through set up intercommunication inlet channel 101 in proper order in main part 100, first air outlet channel 103 and second air outlet channel 104, flow for gas provides the route, through set up annular gas circuit 102 between first air outlet channel 103 and second air outlet channel 104, make the gas that flows out by first air outlet channel 103 can get into rather than the annular gas circuit 102 of intercommunication, the structure of annular gas circuit 102 makes gas fall into two parts and flow towards both sides respectively, until converging the second air outlet channel 104 with annular gas circuit 102 intercommunication, therefore, it can be discharged fast to remain other gas in inside before the gas inflow, cleaning speed has been improved, the problem of the inside residual gas of valves cleaning time overlength among the prior art has been solved.

In the gas passage selection device 1000 in this embodiment, the number of the on-off valves 200, the number of the air inlet channels 101, and the number of the first air outlet channels 103 are equal, the specific number of the air inlet channels 101 and the specific number of the first air outlet channels 103 may be two, three, four, and the like, and accordingly, the number of the on-off valves 200 may be two, three, four, and the like; the number of the gas channels in the present embodiment is not specifically limited, and the gas channels may be selectively set according to an apparatus or a system to which the gas channel selection device 1000 is applied, for example, when four gases are required to be selectively detected or metered, four gas inlet channels 101 and four gas outlet channels 103 may be respectively provided, and four on-off valves 200 are provided.

The main body 100 of the gas passage selection apparatus 1000 in this embodiment is used to provide a passage for gas to flow in and out, the main body 100 may be configured as a cubic structure having the above-mentioned gas flow passages inside, illustratively, the annular gas passage 102, the plurality of gas inlet passages 101, the plurality of first gas outlet passages 103 and the second gas outlet passage 104 are all formed inside the main body 100, as shown in fig. 2, according to the flow direction of the gas flow, the plurality of gas inlet passages 101 arranged inside the main body 100 are respectively communicated with the gas inlet ends of the plurality of on-off valves 200, the gas outlet ends of the plurality of on-off valves 200 are respectively communicated with the plurality of first gas outlet passages 103 arranged inside the main body 100, the plurality of first gas outlet passages 103 are respectively communicated with the annular gas passage 102, and the annular gas passage 102 is communicated with the second gas outlet passage 104, thereby, the gas can enter the main body 100 through the gas inlet passages 101, then flow into the on-off valves 200, and enter the main body 100 through the first gas outlet passages 103 after flowing out from the on-off valves 200, then flows into the annular gas path 102, and finally flows out of the second gas outlet channel 104. It can be understood that other gases remaining in the main body 100 can be rapidly discharged during the process of flowing the gas into the second gas outlet channel 104 through the annular passage in this embodiment.

In this embodiment, the main body 100 may also include a plurality of components, and for example, the main body 100 includes a first valve plate 110 and a second valve plate 120 that are connected in a snap-fit manner, as shown in fig. 3 and 4, the first valve plate 110 and the second valve plate 120 are both configured as rectangular parallelepiped plates, and one side of the first valve plate 110 is attached to one side of the second valve plate 120, on this basis, the first valve plate 110 and the second valve plate 120 may be further connected by bolts 600 or screws.

Illustratively, with continuing reference to fig. 3 and 4, the gas passage selecting device 1000 includes a plurality of bolts 600, the first valve plate 110 is provided with first connecting holes 114 at positions near four corners, the second valve plate 120 is provided with second connecting holes 124 at corresponding positions, the first connecting holes 114 can be set as unthreaded holes, and the second connecting holes 124 can be set as threaded blind holes, so that the bolts 600 pass through the first connecting holes 114 and connect in the second connecting holes 124 to further connect the first valve plate 110 with the second valve plate 120, thereby improving the reliability of the connection between the first valve plate 110 and the second valve plate 120.

On the basis of the above embodiment, the air inlet channel 101 and the first air outlet channel 103 are respectively arranged in the first valve plate 110 and the second valve plate 120, that is, the air inlet channel 101 includes a portion arranged on the first valve plate 110 and a portion arranged on the second valve plate 120, and the first air outlet channel 103 also includes a portion arranged on the first valve plate 110 and a portion arranged on the second valve plate 120, and after the first valve plate 110 and the second valve plate 120 are connected in a snap-fit manner, the portions are respectively aligned and communicated, so as to provide a passage for the flow of air.

On the basis of the above embodiment, the annular air passage 102 may be formed on the first valve plate 110 and the second valve plate 120, that is, the annular air passage 102 may include an annular groove provided on the first valve plate 110 and an annular groove provided on the second valve plate 120, which are engaged to form the annular air passage 102 after the first valve plate 110 is engaged with the second valve plate 120; the annular gas passage 102 may be formed only on the first valve plate 110 or only on the second valve plate 120.

On the basis of the above embodiment, the second air outlet passage 104 is provided in the first valve plate 110 or the second valve plate 120, it is understood that the annular air passage 102 communicates with the second air outlet passage 104, and when the annular air passage 102 is formed on the first valve plate 110 and the second valve plate 120, the second air outlet passage 104 is provided in the first valve plate 110 or the second valve plate 120; when the annular gas passage 102 is provided only on the first valve plate 110, the second gas outlet passage 104 is provided in the first valve plate 110; when the annular gas passage 102 is provided only on the second valve plate 120, the second gas outlet passage 104 is provided in the second valve plate 120.

Further, in some embodiments of the present invention, as shown in fig. 5 to 8, each of the air inlet passages 101 includes a first vent hole 111 formed in the first valve plate 110 and a second vent hole 121 formed in the second valve plate 120, the first vent hole 111 and the second vent hole 121 are equal in number and are aligned and communicated with each other, and on the basis, as shown in fig. 3, the on-off valve 200 is disposed at the other side of the second vent hole 121 and is communicated with the second vent hole 121, so that the air flows into the first valve plate 110, enters the second vent hole 121 of the second valve plate 120 through the first vent hole 111, and then enters the on-off valve 200.

In addition to the above-described embodiment, the gas entering the on-off valve 200 is determined by the on-off valve 200 to flow out, and flows out from the gas outlet end of the on-off valve 200 when flowing out, and since the on-off valve 200 is disposed on the side of the second valve plate 120 away from the first valve plate 110, as shown in fig. 7 and 8, the first gas outlet passage 103 is disposed on the second valve plate 120 in the present embodiment. On this basis, in order to shorten the gas flow path and ensure the accuracy of the detection result, the annular gas path 102 may also be disposed on the second valve plate 120, that is, the gas entering the first gas outlet channel 103 may rapidly flow into the annular gas path 102, specifically, the annular gas path 102 may be disposed inside the second valve plate 120, or may be disposed on a side of the second valve plate 120 away from the on-off valve 200.

Further, as shown in fig. 5 and 6, the second outlet passage 104 is provided in the first valve plate 110, and taking the orientation shown in fig. 3 as an example, the on-off valve 200 is provided above the second valve plate 120, and the second valve plate 120 is provided above the first valve plate 110, and when the annular gas passage 102 is provided on the side of the second valve plate 120 facing away from the on-off valve 200, that is, the annular gas passage 102 is provided on the side of the second valve plate 120 facing the first valve plate 110, the second outlet passage 104 is provided in the first valve plate 110 so as to communicate with the annular gas passage 102.

On the basis of the above-described embodiment, air inlet channel 101 has air inlet 112, and second air outlet channel 104 has air outlet 113, and it can be understood that, as shown in fig. 6, a plurality of air inlets 112 and one air outlet 113 are provided on first valve plate 110, specifically, air inlets 112 and air outlets 113 are respectively located on two opposite sides of first valve plate 110, and each air inlet 112 is communicated with one first vent hole 111, an L-shaped air inlet channel is formed in first valve plate 110, and air outlet 113 is communicated with second air outlet channel 104, and an L-shaped air outlet channel is formed in first valve plate 110.

Further, in some embodiments of the present invention, the gas passage selecting device 1000 further includes a plurality of cutting sleeves 300, as shown in fig. 3, the cutting sleeves 300 are connected to each of the gas inlet 112 and the gas outlet 113 through cutting sleeve screws 400, it should be noted that the cutting sleeve screws 400 and the cutting sleeves 300 are both provided with gas holes for gas to flow through along the axial direction, the cutting sleeves 300 located in the gas inlet 112 are in interference fit with the gas inlet 112, and the cutting sleeves 300 located in the gas outlet 113 are in interference fit with the gas outlet 113.

On the basis of the above embodiment, the annular gas path 102 is disposed on the side of the second valve plate 120 facing the first valve plate 110, for example, in some embodiments of the present invention, the side of the second valve plate 120 facing the first valve plate 110 is provided with the groove 122, and the annular gas path 102 is disposed in the groove 122.

In some embodiments of the present invention, as shown in fig. 7, a first gasket 510 and a second gasket 520 are disposed in the groove 122, and the annular first gasket 510 surrounds the periphery of the second gasket 520, thereby forming an annular air path 102 between the first gasket 510 and the second gasket 520.

Specifically, the first gasket 510 is disposed in an annular shape, and an outer side surface of the first gasket 510 is attached to an inner side surface of the groove 122, and may be disposed in an interference fit manner, so that the reliability of the connection between the first gasket 510 and the second valve plate 120 is ensured. The second gasket 520 may be rectangular, so that an annular gap is formed between the first gasket 510 and the second gasket 520, and the annular gap serves as the annular air passage 102.

In this embodiment, the second gasket 520 is bonded to the bottom of the groove 122 or clamped by a connector, for example, as shown in fig. 7, a connection post 123 is disposed in the groove 122, a connection hole 521 is disposed on the second gasket 520, the connection post 123 is matched with the connection hole 521, the number of the connection post 123 may be one or multiple, correspondingly, the number of the connection holes 521 is equal to that of the connection posts 123, and the connection posts 123 and the connection holes 521 are in interference fit, so that the reliability of connection between the second gasket 520 and the second valve plate 120 is ensured.

In addition to the above-described embodiments, in order to ensure the flow of gas, as shown in fig. 7, the first gasket 510 is provided with a plurality of through holes 511, and the plurality of through holes 511 and the plurality of second vent holes 121 are coaxially disposed in one-to-one correspondence, and it can be understood that the second vent holes 121 communicate with the first vent holes 111 of the first valve plate 110, and therefore, when the first valve plate 110 and the second valve plate 120 are coupled to each other by engagement, the axes of the first vent holes 111, the through holes 511 of the first gasket 510, and the second vent holes 121 coincide and communicate with each other.

Further, in some embodiments of the present invention, the thickness of the first gasket 510 and the second gasket 520 is equal to the depth of the groove 122, that is, after the first gasket 510 and the second gasket 520 are connected in the groove 122, the top of the first gasket 510 and the second gasket 520 is flush with the surface of the side of the second valve plate 120 facing the first valve plate 110, such an arrangement facilitates the snap-fit connection of the first valve plate 110 and the second valve plate 120.

In addition, when the first gasket 510 and the second gasket 520 have elasticity, such as being provided as rubber gaskets, the thickness of the first gasket 510 and the second gasket 520 may be slightly greater than the depth of the groove 122, and after the first valve plate 110 is fastened to the second valve plate 120, the first gasket 510 and the second gasket 520 are compressed by a force, thereby ensuring the sealing performance of the annular air passage 102.

The embodiment of the utility model provides a natural gas check out test set is proposed to embodiment of second aspect, natural gas check out test set includes air feeder, online gas chromatograph and the gas access selection device 1000 that proposes according to any embodiment above, in this embodiment, gas access selection device 1000 sets up between air feeder and online gas chromatograph to be linked together with air feeder and online gas chromatograph respectively, specifically, air feeder is linked together with gas access selection device 1000's inlet channel 101, gas access selection device 1000's second outlet channel 104 is linked together with online gas chromatograph.

In an alternative embodiment, as shown in fig. 3 and 6, a plurality of gas inlets 112 and a plurality of gas outlets 113 are respectively arranged on both sides of the first valve plate 110, and on the basis of this, the gas supply device is communicated with the plurality of gas inlets 112, that is, a plurality of natural gas gases can be supplied to the gas passage selection device 1000; the gas outlet 113 is communicated with an on-line gas chromatograph, and one of the natural gas gases selectively conveyed by the gas passage selection device 1000 can flow into the on-line gas chromatograph for detection.

The utility model provides a natural gas check out test set has the same advantage with gas passage selection device 1000 in above-mentioned embodiment, no longer gives unnecessary details here.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (13)

1. A gas passage selection device, comprising:

the gas-liquid separator comprises a main body, wherein an annular gas circuit, a plurality of gas inlet channels, a plurality of first gas outlet channels and a second gas outlet channel are arranged in the main body, the plurality of gas inlet channels are respectively communicated with the plurality of first gas outlet channels in a one-to-one correspondence manner, and the annular gas circuit is communicated between the plurality of first gas outlet channels and the second gas outlet channels;

and each on-off valve is arranged between one air inlet channel and one first air outlet channel which are communicated.

2. The gas passage selection device according to claim 1, wherein the body includes a first valve plate and a second valve plate which are snap-fit connected, the inlet channel and the first outlet channel are respectively pierced in the first valve plate and the second valve plate, the annular gas passage is formed on the first valve plate and/or the second valve plate, and the second outlet channel is provided in the first valve plate or the second valve plate.

3. The gas passage selection device according to claim 2, wherein the intake passage includes a plurality of first vent holes formed in the first valve plate and a plurality of second vent holes formed in the second valve plate, both ends of the second vent holes communicating with the first vent holes and the intake end of the on-off valve, respectively.

4. The gas passage selection device of claim 3, wherein the first gas outlet channel and the annular gas passage are provided on the second valve plate, and the second gas outlet channel is provided on the first valve plate.

5. The gas passage selection device according to claim 4, wherein the first valve plate is provided with a plurality of gas inlets and a gas outlet, the plurality of gas inlets are respectively communicated with the plurality of first ventilation holes, and the gas outlet is communicated with the second gas outlet channel.

6. The gas pathway selection device of claim 5, further comprising a plurality of ferrules connected in each of the gas inlet and gas outlet ports by ferrule screws.

7. The gas passage selection device according to claim 4, wherein a side of the second valve plate facing the first valve plate is provided with a groove, and the annular gas passage is provided in the groove.

8. The gas pathway selection device of claim 7, wherein a first seal and a second seal are disposed within the groove, the first seal being disposed annularly and peripherally about the second seal, the annular gas path being formed between the first seal and the second seal.

9. The gas passage selection device according to claim 8, wherein a plurality of through holes are provided in the first gasket, and the plurality of through holes are provided coaxially with a plurality of the second vent holes in one-to-one correspondence.

10. The gas channel selection device of claim 8, wherein the thickness of the first and second gaskets is equal to the depth of the groove.

11. The gas pathway selection device of claim 8, wherein a connection post is disposed within the groove, and a connection hole is disposed on the second gasket, the connection post cooperating with the connection hole.

12. The gas passage selection device according to any one of claims 1 to 11, wherein there are four inlet channels, four first outlet channels, and four on-off valves.

13. A natural gas detection apparatus, comprising:

a gas supply device;

an online gas chromatograph;

the gas passage selection device according to any one of claims 1 to 12, which communicates between the gas supply device and the on-line gas chromatograph.

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