Multipath switching system
Through the cascade design of multi-stage small multi-channel valves and drainage pumps, combined with the internal standard gas mixing and valve jump method, the problems of large dead volume and slow switching speed of multi-channel switching devices in chemical park waste gas monitoring are solved, and fast and accurate gas analysis is achieved.
Patent Information
- Application Number
- CN202423253321.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-28
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2034-12-28
AI Technical Summary
In the existing technology, waste gas odor monitoring in chemical parks requires the use of multiple expensive mass spectrometers, and traditional multi-channel switching devices have problems such as large dead volume and slow switching speed.
A combination of multi-stage small multi-channel valves and drainage pumps is used in a cascade structure, combined with internal standard gas mixing and valve jump methods to reduce dead volume and achieve rapid switching.
It achieves rapid and accurate monitoring of multiple sample points, reduces dead volume, improves switching speed and analysis frequency, and reduces equipment costs.
Smart Images
Figure CN223484002U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas analysis technology. Background Technology
[0002] Chemical industrial parks have a high density of enterprises, consume large amounts of volatile organic compounds (VOCs) from raw and auxiliary materials, and produce a wide variety of products. Odor pollution caused by waste during production is a prominent environmental problem. To monitor odors in waste gas, a mass spectrometer capable of detecting hundreds of substances is required. However, due to the large number of monitoring points and the high cost of mass spectrometers, a solution of using a single precision analytical instrument to monitor multiple points is the only viable option.
[0003] Given the complex composition, numerous locations, and large area of pollution emissions from industrial enterprises and chemical industrial parks, using a high-performance analytical instrument in conjunction with a multi-channel sample collection and switching device to collect and monitor gas samples from dozens of locations is an economical and reasonable technical choice.
[0004] Industrial gas selectors are typically used to control and distribute multiple gases to different process flows, and are an important component of industrial automation and gas management. They are used to solve the problem of switching between multiple gas channels. This device allows a single analytical instrument to be connected to different sample gas lines at different times, thus enabling the analysis of multiple sample channels using a single instrument.
[0005] Traditional multi-channel switching devices use a single multi-channel valve to control all pipelines, connecting the gas from the selected pipeline to the analyzer. The system then switches to the next channel after the analyzer has completed its analysis. Utility Model Content
[0006] In view of this, the present invention provides a multi-way switching system, comprising: a primary valve, a secondary valve, a solenoid valve, and a siphon pump; the primary valve 1 and the secondary valve 2 are cascaded; the primary valve is a multi-way switching valve, comprising: a primary valve common outlet, a primary valve selection channel, and multiple secondary valve input interfaces; the secondary valve is a multi-way switching valve, comprising: a secondary valve common outlet, a secondary valve selection channel, and multiple secondary valve input interfaces; the primary valve common outlet and the secondary valve selection channel are connected together to a manifold; the primary valve selection channel is connected to the secondary valve input interface; the solenoid valve is connected to the secondary valve input interface.
[0007] Furthermore, each of the primary valves has an input port that is blocked.
[0008] Furthermore, a drainage pump is installed on the manifold.
[0009] Furthermore, the primary valve selection channel is connected to the secondary valve input interface, including: the first primary valve selection channel is connected to the first secondary valve input interface; the second primary valve selection channel is connected to the second secondary valve input interface; the third primary valve selection channel is connected to the fourth secondary valve input interface; and the fourth primary valve selection channel is connected to the fifth secondary valve input interface.
[0010] Furthermore, the secondary valve is connected to the analyzer inlet via a common outlet.
[0011] Furthermore, the solenoid valve is connected to the secondary valve input interface, including: the first solenoid valve is connected to the third secondary valve input interface; and the second solenoid valve is connected to the sixth secondary valve input interface.
[0012] Furthermore, the other end of the solenoid valve is connected to the internal standard gas.
[0013] The device of this invention uses a small multi-channel valve with a co-flow structure, which allows for the mixing of multiple input samples; in addition, the design minimizes dead volume, ensuring that the gas in all pipelines is in a state of continuous flow and renewal as much as possible. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a multiplexing system architecture.
[0015] Among them, 1 is the primary valve, 2 is the secondary valve, 3 is the solenoid valve, 4 is the dredging pump, 11 is the primary valve common outlet, 12 is the primary valve selection channel, 13 is the secondary valve input interface, 21 is the secondary valve common outlet, and 22 is the secondary valve selection channel. Detailed Implementation
[0016] Example
[0017] In view of this, the present invention provides a multi-channel switching system that extracts samples from different locations to the vicinity of the analyzer for analysis one by one.
[0018] A multi-way switching valve with common outflow has multiple inlet channels, one selectable channel (outlet), and one common outflow channel (outlet). At any given time, if the switching valve selects a specific inlet channel, that inlet channel is connected to the selectable channel. The remaining inlet channels are all connected to the common outflow channel, but not to any of the selectable channels.
[0019] Dead volume generally refers to the enclosed space in a switching valve or system where the gas is not flowing during specific operating phases. Therefore, a system with dead volume must have its gas replaced before a fresh gas sample can be obtained.
[0020] The multi-channel switching system includes: four primary valves 1, one secondary valve 2, two solenoid valves 3, two solenoid valves 4, and a drainage pump 4.
[0021] The primary valve 1 and the secondary valve 2 are cascaded together.
[0022] The primary valve is a multi-way switching valve, comprising: a primary valve common outlet 11, a primary valve selection channel 12, and multiple secondary valve input interfaces. One input interface of each primary valve is blocked.
[0023] The secondary valve is a multi-way switching valve, including: a secondary valve common outlet 21, a secondary valve selection channel 22, and multiple secondary valve input interfaces.
[0024] The four primary valves and the secondary valve selection channel are connected together to the manifold; a dredging pump is installed on the manifold.
[0025] The primary valve selection channel is connected to the secondary valve input interface. Specifically, the first primary valve selection channel is connected to the first secondary valve input interface; the second primary valve selection channel is connected to the second secondary valve input interface; the third primary valve selection channel is connected to the fourth secondary valve input interface; and the fourth primary valve selection channel is connected to the fifth secondary valve input interface.
[0026] The secondary valve is connected to the analyzer inlet via a common outlet.
[0027] The solenoid valve is connected to the input interface of the secondary valve, and the other end of the solenoid valve is connected to the internal standard gas for internal standard gas input. Specifically, the first solenoid valve is connected to the input interface of the third secondary valve; the second solenoid valve is connected to the input interface of the sixth secondary valve.
[0028] The pipeline distance between the outlet of the primary valve's selector channel and the inlet of the secondary valve's input interface should be as short as possible to ensure that the sample enters the secondary valve within less than 0.5 seconds after exiting the primary valve. This ensures that the pre-selected pipeline sample is the freshest possible.
[0029] The multi-channel valve selected in this invention has a very small dead volume, thus minimizing the influence of samples between adjacent channels. Furthermore, a "skip-valve" method is employed in the workflow. During sampling, the selector valve ports of adjacent sampling channels are different, ensuring that only a section of the pipeline at the selector valve outlet is shared during each switch, while the remaining pipelines are exclusively used.
[0030] This invention employs a multi-channel valve with a co-flow structure, cascading multiple multi-channel valves into a system with even more channels. The mixing of sample and internal standard is achieved through the co-flow outlet, enabling accurate capture of the target sample during rapid switching. Samples from all channels maintain continuous flow through the co-flow channel of the second-highest level valve and the gate channel of the highest-level valve.
[0031] This utility model also provides a method for analyzing gas using a multi-channel switching system with a multi-stage switching valve as the core, comprising the following steps:
[0032] 1. When analyzing a gas in a certain channel, the gas sample and the first internal standard gas are mixed and then enter the analyzer together.
[0033] 2. When switching to the next gas channel, the new gas will be mixed with the second internal standard gas before entering the analyzer.
[0034] 3. The gas in the third channel will be mixed with the first internal standard gas, and so on.
[0035] The analyzer's analysis frequency is at least five times higher than the channel switching frequency.
[0036] The analyzer allows observation of alternating rises and falls in the gas concentrations of different internal standards. The trend in internal standard concentration indicates whether the sample in the corresponding channel has reached equilibrium. Ideally, the data segment after the internal standard concentration has risen and stabilized is selected as the valid data for the gas sample in the target channel. If the switching speed is too fast, and the internal standard concentration has not yet stabilized before switching to the next channel, the sampling time with the highest internal standard concentration is selected as the valid data for the channel's gas sample.
[0037] To ensure rapid switching and reduce sample dead volume, while analyzing the gas sample in the current channel, the next sample to be analyzed is connected to the gate channel of the highest-level valve via a secondary-level valve. The output of the gate channel is connected to a flow pump, thus ensuring continuous flow of the sample and preventing dead volume caused by sample cessation. The structural design minimizes the pipeline length from the secondary-level valve to the highest-level valve, ensuring gas replacement is completed within half an analysis cycle.
[0038] To minimize interference and impact, all other secondary valves not involved in sample selection are switched to blocked channels. This ensures that gas from all channels exits through the common flow outlet of the secondary valves, maintaining gas flow in the channels. The input to the highest-level valve is then set to blocked.
[0039] Here is a specific example: Suppose the sample to be analyzed is channel 1 of the first-stage valve, and the next sample to be tested is channel 3 of the second-stage valve.
[0040] During operation, the first-stage valve is switched to channel 1, and the sample is output through the selection channel into the second-stage valve selection channel 1. The remaining first-stage valves, channels 2 to 8, are all connected to the common flow outlet to maintain gas flow, ensuring that the gas in the remaining pipelines is always the freshest sample.
[0041] The first and second internal standard gases connected to the secondary valve can only have one output at a time. Taking the first internal standard gas connection as an example, after the sample enters the secondary valve, it mixes with the first internal standard gas and is output to the analyzer from the co-flow outlet.
[0042] The secondary valve selects the next channel to be measured, thus ensuring continuous sample flow in the next channel to be tested.
[0043] The remaining three channels of the secondary valve are in the following states:
[0044] Second internal standard gas: Closed;
[0045] The third and fourth stage valves: switch to the blocked port (closed state) to prevent irrelevant gas from entering the common flow outlet.
[0046] Therefore, in the current state, only the first internal standard gas and the sample from channel 1 of the first stage valve enter the analyzer.
[0047] After completing the analysis of the sample in the current channel, switch to the next channel: switch the first-stage valve to the blocking channel, switch the second-stage valve to channel 3, and the sample is output through the second-stage valve's gate channel into the second-stage valve.
[0048] The remaining second-stage valves select channels 2 to 8, which are all connected to the common flow outlet to maintain gas flow and ensure that the gas in the remaining pipelines is always the freshest sample.
[0049] The first internal standard gas connected to the secondary valve is closed, and the second internal standard gas is opened. The sample from the three channels of the second primary valve is mixed with the second internal standard gas in the secondary valve and then output to the analyzer through the co-flow outlet.
[0050] The secondary valve selects the next channel to be measured, ensuring continuous sample flow in the next test channel. The sample in the next test channel will mix with the first internal standard gas, thus distinguishing adjacent samples.
[0051] To avoid increasing the system dead volume through the piping between the primary and secondary valves, the system structure design places adjacent switching channels (adjacent sampling channels during round-robin switching) on different primary valves. This ensures that the secondary valve actuates with each switch, allowing new samples already flowing through the secondary valve's selection channel to directly pass through and enter the analyzer, reducing dead volume and waiting time. Otherwise, if only the primary valve actuates, the gas sample from the new channel must first displace the gas in the entire pipeline from the primary to the secondary valve before reaching it.
[0052] To achieve rapid switching, while the system is analyzing channel 1 of the first-stage valve, preparation work for the next test channel has already begun. Assume the next test channel is channel 3 of the second-stage valve. Then, when the system analyzes channel 1 of the first-stage valve, the second-stage valve switches the channel to test channel 3, and simultaneously, the secondary valve sets the selected channel on the second-stage valve to maintain continuous sample flow within the test channel.
[0053] This invention utilizes multiple small multi-channel valves combined with a unique switching control method, employs internal standard gas to adjust the gas sample being tested, and incorporates unique designs such as a trip valve to achieve the beneficial effect of high-frequency channel switching.
[0054] The feature of this utility model patent lies in the use of multiple small multi-channel valves, which are cascaded together, with the output of the first-stage valve connected to the input of the second-stage valve. The aforementioned defects are solved through the following method.
[0055] 1. The small multi-channel valve has a co-flow structure, so it can mix multiple input samples.
[0056] When switching sampling channels, the system uses two input channels: one for the analyte sample and the other for an internal standard component that cannot be found in either channel. The two components are mixed before entering the analyzer. During switching, the concentrations of both the internal standard and the analyte sample change simultaneously. Since the internal standard component has a fixed composition and concentration and is unaffected by interference, the change in its response can be used to determine whether the sample from the switched channel has completely entered the analyzer. This method allows for sample modulation, enabling faster system switching without sample mixing between channels. The flow rate of the internal standard component is much lower than the sample flow rate, therefore it does not dilute the sample.
[0057] 2. In its design, this utility model minimizes dead volume, ensuring that the gas in all pipelines is in a state of continuous flow and renewal as much as possible.
[0058] In this invention, the dead volume pipeline mainly includes a section from the common outlet port of the secondary valve to the analyzer. The remaining pipelines are connected to the system duct pump through common outlets or selective channels, thus maintaining a state of constant flow renewal.
[0059] In this invention, the dead volume pipeline is solely a gas pipeline, lacking any drive shaft or supporting structure, thus allowing it to be designed to be very short and directly enter the analyzer. The length of the common outlet pipe for the secondary valve, serving as the common outlet for all channels, can be controlled to 50mm or even shorter, minimizing the impact of dead volume on the switching effect.
[0060] When switching between multiple channels, the system can pre-connect the next channel to be analyzed to the secondary valve, using its co-flow to maintain sample flow. During channel switching, only the channel of the secondary valve needs to be changed. Since the dead volume is only within the secondary valve, the gas in the common pipeline can be replaced in a very short time after the secondary valve is switched, thus achieving rapid channel switching. This method allows for pipeline pre-selection, further accelerating the switching speed.
[0061] 3. This utility model uses a combination of multiple small multi-channel valves to achieve switching. The individual valve discs are small, and the switching time is short. The valves at all levels operate synchronously, further reducing the switching time.
Claims
1. A multiplexing system, characterized in that it includes: Primary valve, secondary valve, solenoid valve, and evacuation pump; The primary valve and the secondary valve are cascaded together. The primary valve is a multi-way switching valve, including: a primary valve common outlet, a primary valve selection channel, and multiple secondary valve input interfaces; The secondary valve is a multi-way switching valve, including: a secondary valve common outlet, a secondary valve selection channel, and multiple secondary valve input interfaces; The common outlet of the primary valve and the gate channel of the secondary valve are connected together to the manifold; The primary valve selection channel is connected to the secondary valve input interface; The solenoid valve is connected to the input interface of the secondary valve.
2. The multiplexing system according to claim 1, characterized in that, Each of the primary valves has one input port that is blocked.
3. The multiplexing system according to claim 1, characterized in that, A diversion pump is installed on the manifold.
4. The multiplexing system according to claim 1, characterized in that, The primary valve selection channel is connected to the secondary valve input interface, including: The first-level valve selection channel is connected to the input interface of the first and second-level valves; The second primary valve selection channel is connected to the input interface of the second and second secondary valves; The third primary valve selection channel is connected to the fourth secondary valve input interface; The fourth primary valve selection channel is connected to the fifth secondary valve input interface.
5. The multiplexing system according to claim 1, characterized in that, The secondary valve is connected to the analyzer inlet via a common outlet.
6. The multiplexing system according to claim 1, characterized in that, There are 1 to 4 primary valves.
7. The multiplexing system according to claim 1, characterized in that, The solenoid valve includes a first solenoid valve and a second solenoid valve.
8. The multiplexing system according to claim 7, characterized in that, The solenoid valve is connected to the input interface of the secondary valve, including: The first solenoid valve is connected to the input interface of the third and second stage valves; The second solenoid valve is connected to the input interface of the sixth secondary valve.
9. The multiplexing system according to claim 8, characterized in that, The other end of the solenoid valve is connected to the internal standard gas.