A reverse-proof gas distribution device and a design method thereof

Abstract

The application discloses a reverse-preventing gas distribution device and a design method thereof, and relates to the technical field of stirring equipment. The device comprises: a gas flow channel suitable for conveying gas while rotating around an axis thereof; and an axial flow impeller coaxially arranged in the gas flow channel and configured to generate a compensation torque T d in the same direction as the rotating direction of the gas flow channel when the gas flows through. By integrating the axial flow impeller in the gas flow channel, a compensation torque T d in the same direction as the rotating direction of the gas flow channel can be generated, which offsets the reverse tangential resistance moment formed due to gas overflow, avoids the problems of speed drop, stop or even reverse rotation of the stirrer due to the "stripping effect", and overcomes the high energy consumption disadvantage of simply relying on increasing the power of the motor in the prior art, while the ventilation position does not need to be changed, and the specific requirements of the process on the gas distribution point are met.

Description

Technical Field

[0001] This application relates to the field of stirring equipment technology, and in particular discloses an anti-reverse gas distribution device and its design method. Background Technology

[0002] In stirred reactors, it is common practice to introduce gas (such as air, oxygen, carbon dioxide, etc.) through the bottom of the reaction liquid via the stirring shaft. However, in such centrally aerated scenarios, after the gas is released from the bottom outlet of the stirring shaft, it will form a high-speed upward gas column due to buoyancy. This upward gas flow will generate a tangential resistance torque on the stirring shaft and the stirring impeller connected to it, which is the "stripping effect". In severe cases, it can cause the stirrer to stop completely or even reverse, which greatly disrupts the expected stirring flow field and affects the mixing, mass transfer and reaction efficiency.

[0003] Existing technologies typically address this problem by increasing the power of the drive motor or changing the ventilation location. However, the former is energy-intensive and uneconomical, while the latter may not meet the process requirements for gas distribution. Furthermore, existing technologies lack a systematic design approach to proactively address the "stripping effect." Designers often rely on experience for qualitative judgments or trial adjustments. This approach is not only inefficient and time-consuming but also difficult to match the actual needs under different operating conditions. The reliability of the design scheme is highly dependent on personal experience and cannot become a universal design solution. Therefore, improvements are needed. Summary of the Invention

[0004] The purpose of this application is to provide an anti-reverse gas distribution device and its design method.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: an anti-reverse gas distribution device, comprising: an airflow channel adapted to transport gas while rotating about its axis; and an axial flow impeller coaxially disposed within the airflow channel, configured to generate a compensating torque T in the same direction as the rotation direction of the airflow channel when gas flows through it. d .

[0006] As a preferred embodiment, during operation, gas enters the airflow channel and flows through the axial flow impeller before being released from the bottom. The released gas overflows onto the outside of the airflow channel and generates a tangential resistance torque T on the airflow channel in the opposite direction to the rotation direction. r And the compensation torque T d Suitable for counteracting tangential resistance torque T r .

[0007] As a preferred embodiment, the axial flow impeller includes a central element, which is configured to be hollow to increase the airflow or solid to increase the compensating torque T. dThe central component has a plurality of blades arranged in a circumferential direction around its rotation axis, and the blades are configured as flat straight blades or helical curved blades.

[0008] As a preferred embodiment, the lower end of the airflow channel is provided with a downward-opening diffuser. The diffuser is conical, and its cone angle ranges from 30° to 120°. The edge of the diffuser has a number of continuously arranged turbulence teeth, and the ratio of the tooth depth to the tooth pitch of the turbulence teeth is 1:3 to 1:10.

[0009] As a preferred embodiment, a check valve is also provided on the airflow channel. The check valve is configured to automatically close when airflow stops in the airflow channel. The check valve includes a one-way ball valve, a one-way butterfly valve, or a duckbill valve.

[0010] A design method for an anti-reverse gas distribution device includes the following steps:

[0011] Step A: Select a stirring device with appropriate parameters according to the working conditions, and determine the gas flow rate Q, gas density ρ, and rated power of the motor;

[0012] Step B: Detect and calculate the power loss P due to the "stripping effect" under ventilation conditions. l According to the torque power calculation formula, P l Converted to tangential resistance torque T r ;

[0013] Step C: Based on the gas flow rate Q and gas density ρ from Step A, calculate the compensation torque T by setting the parameters of the axial flow impeller. d ;

[0014] Step D: By adjusting the parameters of the axial flow impeller in step C, the compensating torque T is adjusted. d Counteracting tangential resistance torque T r This allows us to determine the specific design parameters of the axial flow impeller.

[0015] As a preferred embodiment, in step B, the rotational speed n is known, and the power P is... l With tangential resistance torque T r The calculation formula between them is expressed as P l = (T r (×2π×n) / 60.

[0016] As a preferred embodiment, in step C, it is assumed that the gas does not rotate when it enters the axial flow impeller, i.e., V θ =0, based on the gas flow rate Q in step A, by setting the diameter d of the axial flow impeller, according to formula V z =(4×Q) / (π×d 2 ), to obtain the axial velocity V of the gas. zWhen the blades are configured as flat, straight blades, the airflow angle β at the blade exit is set according to formula V. θ =V z ×tanβ=(4×Q×tanβ) / (π×d 2 The circumferential velocity V of the airflow is obtained. θ When the blades are configured as helical curved blades, the pitch P is set. 螺距 Pitch P 螺距 The airflow angle β at the blade exit satisfies tanβ=P 螺距 / (π×d), according to the formula V θ =V z ×tanβ=(4×Q×tanβ) / (π×d 2 The circumferential velocity V of the airflow is obtained. θ .

[0017] Further optimization, in step C, the gas density ρ is assumed to be constant, and the effective gas volume Q1 = ε × Q is set, where ε is the effective gas volume ratio, ranging from 0 to 1, and is proportional to the ratio of the top-view projected area of ​​the axial flow impeller to the cross-sectional area of ​​the airflow channel; based on the circumferential velocity V of the airflow... θ It has been calculated that, according to the formula F=ρ×Q1×V θ =(4×ρ×ε×Q 2 ×tanβ) / (π×d 2 ), thus obtaining the tangential force F exerted by the gas on the axial impeller.

[0018] Further preferably, in step C, let the average radius r m =d / 3, which is equivalent to the effective radius of the tangential force F acting on the axial impeller; based on the calculated tangential force F of the gas acting on the axial impeller, according to formula T d =F×r m =(4×ρ×ε×Q 2 ×tanβ) / (3π×d), we get the compensation torque T d .

[0019] As a preferred embodiment, in step D, different compensation torques T are calculated by adjusting the specific values ​​of three parameters: the effective air volume ratio ε, the blade outlet airflow angle β, and the axial impeller diameter d. d When the compensation torque T d Counteracting tangential resistance torque T r When determining the corresponding effective air volume ratio ε, blade outlet airflow angle β, and axial impeller diameter d, a set of effective axial impeller design parameters is established.

[0020] Compared with the prior art, the beneficial effects of this application are as follows:

[0021] (1) The anti-reverse gas distribution device of the present invention integrates an axial flow impeller in the airflow channel, which can effectively generate a compensating torque T in the same direction as the rotation direction of the airflow channel after the gas is introduced. d This directly offsets the reverse tangential resistance torque caused by gas overflow mentioned in the background technology, significantly enhancing the operational stability of the stirring system under central aeration conditions. This device not only effectively avoids problems such as reduced speed, stoppage, or even reversal of the stirrer due to the "stripping effect," ensuring the stability of the flow field structure and mixing state within the reactor, but also overcomes the high energy consumption drawback of simply increasing motor power in existing technologies. At the same time, it does not require changing the aeration position, fully meeting the specific requirements of the process for gas distribution points. While ensuring efficient gas dispersion and mass transfer, it achieves a balance between energy saving and operational reliability, significantly improving the overall efficiency and economy of the reaction process.

[0022] (2) The design method of this application calculates the tangential drag torque T by testing. r Then, the compensation torque T is calculated by designing the parameters of the axial flow impeller. d Finally, the compensation torque T is matched by adjusting the parameter values ​​of the axial flow impeller. d With tangential resistance torque T r This forms a complete design path, serving as a general design framework, thereby ensuring that the compensation torque T obtained from the finally determined axial flow impeller parameters is achieved. d It can in principle counteract the tangential resistance torque T r This fundamentally ensures the reliability of the design scheme, thereby making the operation more efficient and economical in practice. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of the anti-reverse gas distribution device equipped with spiral curved blades according to the present invention.

[0024] Figure 2 This is a three-dimensional cross-sectional view of the anti-reverse gas distribution device equipped with spiral curved blades according to the present invention.

[0025] Figure 3 This is a three-dimensional structural diagram of the axial flow impeller equipped with helical curved blades according to the present invention.

[0026] Figure 4 This is a three-dimensional structural diagram of the anti-reverse gas distribution device of the present invention, equipped with another type of spiral curved blade.

[0027] Figure 5 This is a three-dimensional structural diagram of an axial flow impeller equipped with another type of helical curved blade according to the present invention.

[0028] Figure 6This is a three-dimensional structural diagram of the anti-reverse gas distribution device equipped with flat straight blades according to the present invention.

[0029] Figure 7 This is a three-dimensional cross-sectional view of the anti-reverse gas distribution device equipped with flat straight blades according to the present invention.

[0030] Figure 8 This is a three-dimensional structural diagram of the axial flow impeller equipped with flat straight blades according to the present invention.

[0031] Figure 9 This is a schematic diagram of the airflow angle β at the blade outlet of the anti-reverse gas distribution device equipped with flat straight blades according to the present invention.

[0032] Figure 10 This is a schematic diagram of another anti-reverse gas distribution device of the present invention.

[0033] Figure 11 This is a schematic diagram of a three-dimensional structure of a check valve according to the present invention.

[0034] Figure 12 This is a schematic diagram of the check valve installation of the present invention.

[0035] Figure 13 This is a schematic diagram of the check valve installation of the present invention.

[0036] Figure 14 This is a schematic diagram of the overall structure of the present invention installed on a stirring device.

[0037] In the diagram: 1. Airflow channel; 11. Air inlet; 2. Diffuser; 21. Turbine tooth; 3. Axial flow impeller; 31. Blade; 32. Central component; 4. Check valve; 41. Air inlet end; 42. Air outlet end. Detailed Implementation

[0038] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0039] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0040] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0041] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0042] In a stirred reactor, gas is introduced into the reaction liquid through the stirring shaft at the bottom. After the gas is released from the outlet at the bottom of the stirring shaft, it forms a high-speed upward-flowing gas column due to buoyancy. This generates a tangential resistance torque T on the stirring shaft and the connected impeller, which is opposite to the set rotation direction. r This is known as the "stripping effect," which in severe cases can cause the agitator to stop completely or even reverse, greatly disrupting the expected mixing flow field and affecting mixing, mass transfer, and reaction efficiency.

[0043] To address the aforementioned issues and ensure smooth production, existing technologies primarily rely on increasing the power of the drive motor or altering the ventilation location. However, both methods have drawbacks. Therefore, a solution is needed that not only efficiently disperses gas but also actively generates a tangential resistance torque T. r Compensating torque T in opposite direction d This device achieves dynamic torque balance, thereby ensuring that the stirring impeller rotates stably in the set direction under aeration conditions.

[0044] A preferred embodiment of this application, such as Figures 1 to 14 As shown, an anti-reverse gas distribution device includes:

[0045] Airflow channel 1, which is adapted to transport gas while rotating about its axis;

[0046] Specifically, in some embodiments, such as Figure 1 , Figure 4 and Figure 6 As shown, the airflow channel 1 is adapted to be coaxially mounted at the bottom of the stirring shaft and rotate synchronously with it. It is connected to the stirring shaft through the air inlet 11 opened on the airflow channel 1. The airflow channel 1 and the stirring shaft can be connected by flange or welding to ensure a firm connection and reliable sealing. It can be clearly seen that the entire device rotates as a whole with the stirring shaft and is driven by the same motor. No additional power source or control system is required, which has high reliability and is easy to modify.

[0047] In other embodiments, such as Figure 10As shown, the airflow channel 1 is the stirring shaft body, which is hollow inside and suitable for conveying gas into the reaction liquid.

[0048] In addition, a diffuser 2 with a downward opening can be provided at the lower end of the airflow channel 1. The diffuser 2 is conical and its cone angle ranges from 30° to 120°. The edge of the diffuser 2 has several continuously arranged turbulence teeth 21. The ratio of the tooth depth to the tooth pitch of the turbulence teeth 21 is 1:3 to 1:10.

[0049] By setting a conical diffuser 2 and turbulence-reducing teeth 21, the gas outlet velocity can be reduced, converting the gas kinetic energy into static pressure energy and promoting bubble refinement. At the same time, the serrated edges of the turbulence-reducing teeth 21 can effectively cut the bubbles that are about to detach, generating more and smaller initial bubbles and disrupting the stability of the gas jet, thereby greatly enhancing the uniformity of gas dispersion in the liquid phase and improving gas-liquid mass transfer efficiency. The ability of this type of diffuser 2 to disperse bubbles far exceeds that of ordinary straight tube or flat-mouth diffusers, which can significantly improve reaction efficiency.

[0050] Check valve 4 is installed in the airflow passage 1;

[0051] In terms of specific selection, check valve 4 can be a one-way ball valve, a one-way butterfly valve, or a duckbill valve. It is understandable that... Figures 11 to 13 As shown, the check valve 4 has an inlet end 41 and an outlet end 42. The inlet end 41 is connected to the inlet port 11, and the outlet end 42 should automatically close when the agitator stops aeration to prevent the liquid in the reactor from flowing back into the agitator shaft and upstream aeration pipe under static pressure, thus avoiding blockage, corrosion, or contamination. As for its installation location, it can be the upstream end of the axial flow impeller 3, such as... Figure 12 As shown, it can also be the downstream end of the axial flow impeller 3, such as... Figure 13 As shown, the above settings can effectively prevent liquid backflow, protect the stirring shaft and upstream pipelines, and reduce the risk of equipment failure and maintenance costs.

[0052] An axial impeller 3 is coaxially disposed within the airflow channel 1 and is configured to generate a compensating torque T in the same direction as the rotation of the airflow channel 1 when gas flows through it. d .

[0053] By installing an axial flow impeller 3 in the airflow channel 1, part of the energy of the incoming gas is converted into a torque T to counteract the tangential resistance. rThe device effectively solves the problem of impeller reversal caused by central ventilation from a kinetic perspective, ensuring stable operation of the mixing process. It not only effectively avoids problems such as reduced speed, stoppage, or even reversal of the agitator due to the "stripping effect," ensuring the stability of the flow field structure and mixing state within the reactor, but also overcomes the high energy consumption drawback of simply increasing motor power in existing technologies. Furthermore, it does not require changing the ventilation location, fully meeting the specific requirements of the process for gas distribution points. While ensuring efficient gas dispersion and mass transfer, it achieves a balance between energy saving, consumption reduction, and operational reliability, significantly improving the overall efficiency and economy of the reaction process.

[0054] It is clear that when the stirring shaft is working, gas enters the airflow channel 1 and flows through the axial flow impeller 3 before being released from the bottom. The released gas overflows onto the outside of the stirring shaft and generates a tangential resistance torque T on the stirring shaft in the opposite direction of rotation. r Meanwhile, due to the aforementioned axial flow impeller 3 design, a compensating torque T is generated when the gas flows through it. d To ensure the stable operation of the agitator, it is necessary to meet the T requirement. d ≈T r It is understandable that, since the gas flow through the axial impeller 3 is not absolutely uniform, the resulting compensating torque T d It is not constant, and due to the rotation of airflow channel 1, there are complex forces between it and the external reaction liquid. In addition, the release of gas from the bottom will generate a tangential resistance torque T on the stirring shaft. r Under these complex operating conditions, the tangential resistance torque T r It is also not constant, therefore T cannot be achieved under actual working conditions. d =T r In practice, satisfying T d ≈T r That's all.

[0055] Specifically, the axial flow impeller 3 includes a central element 32, which is configured to be hollow to increase the airflow or solid to increase the compensating torque T. d Furthermore, when the central component 32 is configured as hollow, for example, it can be designed as a hollow tube structure, allowing gas to flow not only from the blades 31 but also from the central component 32, increasing the airflow. When the central component 32 is configured as solid, for example, it can be designed as a solid cylindrical structure. This structure increases the weight of the axial impeller 3, thereby increasing its moment of inertia and generating greater angular momentum at the same rotational speed, thus increasing the compensating torque T. d For resisting the tangential resistance torque T r With enhanced stability, the central component 32 has several blades 31 arranged in a circumferential array around its axis of rotation. The blades 31 are configured as flat straight blades or helical curved blades, such as... Figures 1 to 5As shown, blade 31 is configured as a helical curved blade, wherein, as Figures 1 to 3 As shown, blade 31 is designed in a form similar to fan blades, such as... Figures 4 to 5 As shown, blade 31 is designed in a form similar to that of a single-suction pump blade, such as... Figures 6 to 9 As shown, blade 31 is configured as a flat, straight blade.

[0056] The above-mentioned design of the center component 32 in two configuration modes, hollow and solid, can provide corresponding solutions for those skilled in the art to meet the two different needs of increasing ventilation and improving anti-reverse performance. By defining the center component 32 in two specific ways, different needs can be met without making more complicated adjustments to other components, thus reducing the difficulty of design.

[0057] The blade angle is designed based on the target gas flow rate, density, and the required counteracting resistance torque, so that the generated driving torque is balanced with the stripping resistance torque acting on the agitator impeller under ventilation conditions.

[0058] When compressed gas enters the device from the stirring shaft through the inlet 11 and flows through the axial impeller 3, according to the principle of angular momentum in fluid mechanics, the angular momentum of the gas changes after passing through the axial impeller 3, thereby applying a rotational torque to the axial impeller 3. By precisely designing the blade angle of the axial impeller 3, the direction of this rotational torque can be aligned with the tangential resistance torque T acting on the stirring impeller due to the stripping effect. r The direction is opposite, and this rotational torque is the aforementioned compensating torque T. d The blade angle is based on the gas flow rate, gas density, and the tangential drag torque T to be offset. r The design is carried out to ensure that the resulting compensation torque T d The tangential resistance torque T acting on the impeller under ventilation conditions r Phase equilibrium.

[0059] More specifically, the compensation torque T d The specific values ​​can be determined based on the gas flow rate Q, gas density ρ, diameter d of the axial impeller 3, and effective gas volume ratio ε, using the formula T. d =(4×ρ×ε×Q 2 The matching calculation is performed using (×tanβ) / (3π×d), where β is the blade outlet airflow angle, thus theoretically achieving a match with the tangential drag torque T. r The active cancellation is important to note. Since the axial impeller 3 is fixedly installed inside the airflow channel 1 and is fixedly connected to the inner wall of the airflow channel 1, the diameter of the axial impeller 3 is equal to the inner diameter of the airflow channel 1.

[0060] Of course, when the stirring shaft is used as airflow channel 1, such as Figure 10As shown, multiple axial flow impellers 3 can be arranged inside it. When the gas flows through, it will exert a force on each axial flow impeller 3, thereby increasing the final compensation torque T. d .

[0061] Based on the above specific structure and the compensation torque T d Based on the analysis, this application provides a design method for an anti-reverse gas distribution device, comprising the following steps:

[0062] Step A: Select a stirring device with appropriate parameters according to the working conditions, and determine the gas flow rate Q, gas density ρ, and rated power of the motor.

[0063] Typically, those skilled in the art select appropriate motors and gas sources based on the characteristics of the reaction liquid, the working environment, and the stirring process. This allows them to set the corresponding gas flow rate Q and gas density ρ. During operation, the gas density ρ is kept constant, and the gas flow rate Q remains stable. The unit of gas density ρ is kilograms per cubic meter (kg / m³). 3 The unit of gas flow rate Q is cubic meters per second (m³ / s). 3 / s).

[0064] Step B: Detect and calculate the power loss P due to the "stripping effect" under ventilation conditions. l According to the torque power calculation formula, P l Converted to tangential resistance torque T r .

[0065] The core formula for power and torque is: P=T×ω, where P is power, in watts (W), T is torque, in newton-meters (N·m), and ω is angular velocity, in radians per second (rad / s).

[0066] In practical engineering, rotational speed n is generally used to replace angular velocity. According to ω=(2π×n) / 60, we can get P=(T×2π×n) / 60, where the unit of rotational speed n is revolutions per minute (r / min).

[0067] Once the motor is determined, the rotational speed n can be set to a known value, at which point the power P... l With tangential resistance torque T r The formula for calculating the relationship between them can be expressed as: P l = (T r (×2π×n) / 60.

[0068] Where P l The power loss can be calculated by detecting the power loss during equipment operation, i.e., P. l Also known, the corresponding tangential resistance torque T can be calculated using the above formula. r This tangential resistance torque Tr These are the parameters that need to be offset in the design of the anti-reverse gas distribution device of this application.

[0069] Step C: Based on the gas flow rate Q and gas density ρ from step A, calculate the compensation torque T by setting the parameters of the axial flow impeller 3. d .

[0070] Specifically, based on the morphology of blade 31, there are the following two calculation methods:

[0071] The first type is when blade 31 is configured as a flat straight blade.

[0072] Assume that the gas does not rotate when it enters the axial flow impeller 3, i.e., V θ =0.

[0073] Based on the gas flow rate Q in step A, by setting the diameter d of the axial impeller 3, according to formula V z =(4×Q) / (π×d 2 ), to obtain the axial velocity V of the gas. z Where the diameter d is in meters (m), and the axial velocity V z The unit is meters per second (m / s).

[0074] By setting the airflow angle β at the blade exit, according to formula V θ =V z ×tanβ=(4×Q×tanβ) / (π×d 2 The circumferential velocity V of the airflow is obtained. θ The unit of the airflow angle β at the blade exit is degrees (°), and the circumferential velocity V is... θ The unit is meters per second (m / s).

[0075] Assume the gas density ρ is constant, and set the effective gas volume Q1 = ε × Q, where ε is the effective gas volume ratio, the range of ε is 0~1, and it is proportional to the ratio of the top-view projected area of ​​the axial impeller 3 to the cross-sectional area of ​​the airflow channel 1.

[0076] Based on the circumferential velocity V of the airflow θ It has been calculated that, according to the formula F=ρ×Q1×V θ =(4×ρ×ε×Q 2 ×tanβ) / (π×d 2 The tangential force F exerted by the gas on the axial impeller 3 is obtained, where the unit of the tangential force F is Newton (N).

[0077] Let the average radius be r m =d / 3, which is equivalent to the effective radius of the tangential force F acting on the axial impeller 3; based on the calculated tangential force F of the gas acting on the axial impeller 3, according to formula T d =F×rm =(4×ρ×ε×Q 2 ×tanβ) / (3π×d), we get the compensation torque T d The compensation torque T d The unit is Newton-meter (N·m).

[0078] Step D: By adjusting the parameters of the axial flow impeller 3 in step C, T d ≈T r This allows us to determine the specific design parameters of the axial flow impeller 3.

[0079] It is understandable that the tangential resistance torque T measured and calculated under actual operating conditions varies at different times. r The tangential resistance torque T is not constant, therefore it is usually not constant. r An average value will be taken and approximated, and the calculated compensation torque T d This is a theoretical value; once all parameters are determined, the compensation torque T... d The value is also determined, but when adjusting the parameters, it is impossible to make the compensation torque T... d The value of the tangential resistance torque T r The values ​​are exactly equal, because T d The relevant formulas contain tanβ and π, and the final result will inevitably be an infinite non-repeating decimal. Therefore, in practice, when calculating the matching compensation torque T... d The value is close to the tangential resistance torque T within the allowable range of the difference. r The value meets the design requirements.

[0080] By adjusting the specific values ​​of three parameters—the effective air volume ratio ε, the blade outlet airflow angle β, and the diameter d of the axial impeller 3—different compensation torques T are calculated. d When T d ≈T r When determining the corresponding effective gas volume ratio ε, blade outlet airflow angle β, and axial impeller diameter d, a set of effective anti-reverse gas distribution device design parameters are established.

[0081] The second type is when blade 31 is configured as a helical curved blade.

[0082] Assume that the gas does not rotate when it enters the axial flow impeller 3, i.e., V θ =0.

[0083] Based on the gas flow rate Q in step A, by setting the diameter d of the axial impeller 3, according to formula V z =(4×Q) / (π×d 2 ), to obtain the axial velocity V of the gas. z Where the diameter d is in meters (m), and the axial velocity V zThe unit is meters per second (m / s).

[0084] By setting the pitch P 螺距 Pitch P 螺距 The airflow angle β at the blade exit satisfies tanβ=P 螺距 / (π×d)where the pitch P 螺距 The unit is meters (m), the unit of the airflow angle β at the blade exit is degrees (°), and the unit of the circumferential velocity V is... θ The unit is meters per second (m / s), according to the formula V θ =V z ×tanβ=(4×Q×P 螺距 ) / (π) 2 ×d 3 The circumferential velocity V of the airflow is obtained. θ .

[0085] Assume the gas density ρ is constant, and set the effective gas volume Q1 = ε × Q, where ε is the effective gas volume ratio, the range of ε is 0~1, and it is proportional to the ratio of the top-view projected area of ​​the axial impeller 3 to the cross-sectional area of ​​the airflow channel 1.

[0086] Based on the circumferential velocity V of the airflow θ It has been calculated that, according to the formula F=ρ×Q1×V θ =(4×ρ×ε×Q 2 ×P 螺距 ) / (π) 2 ×d 3 The tangential force F exerted by the gas on the axial impeller 3 is obtained, where the unit of the tangential force F is Newton (N).

[0087] Let the average radius be r m =d / 3, which is equivalent to the effective radius of the tangential force F acting on the axial impeller 3; based on the calculated tangential force F of the gas acting on the axial impeller 3, according to formula T d =F×r m =(4×ρ×ε×Q 2 ×P 螺距 ) / (3π 2 ×d 2 ), to obtain the compensation torque T d The compensation torque T d The unit is Newton-meter (N·m).

[0088] Step D: By adjusting the parameters of the axial flow impeller 3 in step C, T d ≈T r This allows us to determine the specific design parameters of the axial flow impeller 3.

[0089] It is understandable that the tangential resistance torque T measured and calculated under actual working conditions at different times is different.r The tangential resistance torque T is not constant, therefore it is usually not constant. r An average value will be taken and approximated, and the calculated compensation torque T d This is a theoretical value; once all parameters are determined, the compensation torque T... d The value is also determined, but when adjusting the parameters, it is impossible to make the compensation torque T... d The value of the tangential resistance torque T r The values ​​are exactly equal, because T d The presence of π in the relevant formulas inevitably results in an infinite non-repeating decimal. Therefore, in practice, when calculating the matching compensation torque T... d The value is close to the tangential resistance torque T within the allowable range of the difference. r The value meets the design requirements.

[0090] By analyzing the effective gas volume ratio ε and the screw pitch P 螺距 By adjusting the specific values ​​of these three parameters—the diameter d of the axial flow impeller 3—different compensation torques T are calculated. d When T d ≈T r At that time, determine the corresponding effective gas volume ratio ε and screw pitch P. 螺距 The diameter d of the axial impeller 3 is a set of design parameters for an effective anti-reverse gas distribution device.

[0091] With tangential resistance torque T r Taking 0.340 N·m as an example, in order to counteract this tangential drag torque T r The specific parameters of the anti-reverse gas distribution device can be set by referring to the two design methods mentioned above:

[0092] In one specific embodiment, blade 31 is configured as a flat, straight blade, and the gas density ρ is set to 1.2 kg / m³. 3 The gas flow rate Q is set to 0.5 m³ / s. 3 / s, the diameter d of the axial impeller 3 is set to 0.3m, the effective air volume ratio ε is set to 0.8, and the blade outlet airflow angle β is set to 45°. Using the above formulas, the axial velocity V can be obtained. z The circumferential velocity V is 7.074 m / s. θ The velocity is 7.074 m / s, the tangential force F is 3.395 N, and the compensating torque T is... d It is 0.340 N·m.

[0093] In another specific embodiment, blade 31 is configured as a helical curved blade, and the gas density ρ is set to 1.2 kg / m³. 3 The gas flow rate Q is set to 0.5 m³ / s. 3 / s, the diameter d of the axial impeller 3 is set to 0.3m, the effective air volume ratio ε is set to 0.8, and the pitch P 螺距 Setting the value to 0.5m, the axial velocity V can be obtained using the aforementioned formulas. z The circumferential velocity V is 7.074 m / s. θ The velocity is 7.074 m / s, the tangential force F is 3.395 N, and the compensating torque T is... d The value is 0.340 N·m, and the blade outlet airflow angle β is 27.9°.

[0094] In practical applications, this device can be used, for example, for stirring the reaction liquid inside a reactor. Figure 14 As shown, specifically, a motor and a reducer can be fixedly installed outside the reactor. A stirring mechanism is connected to the reducer, and this device is installed on the stirring mechanism. Gas enters from the top of the stirring mechanism and exits from the bottom. After the gas is discharged, it is broken by the stirring impeller, which increases the contact area with the reaction liquid. Under the action of the stirring impeller, a circulation is formed in the reaction liquid, making the overall mixing more uniform.

[0095] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A gas distribution device for preventing reverse gas flow, characterized in that, include: An airflow channel adapted to transport gas while rotating about its axis; An axial flow impeller is coaxially disposed within the airflow channel and configured to generate a compensating torque T in the same direction as the rotation of the airflow channel when gas flows through it. d ; The axial flow impeller includes a central element, which is configured to be hollow to increase the airflow or solid to increase the compensating torque T. d The central component has a plurality of blades arranged in a circumferential direction around its rotation axis, and the blades are configured as flat straight blades or helical curved blades.

2. The anti-reverse gas distribution device as described in claim 1, characterized in that, During operation, gas enters the airflow channel and flows through the axial flow impeller before being released from the bottom. The released gas overflows onto the outside of the airflow channel and generates a tangential resistance torque T on the airflow channel in the opposite direction of rotation. r And the compensation torque T d Suitable for counteracting tangential resistance torque T r .

3. The anti-reverse gas distribution device as described in claim 1, characterized in that, The lower end of the airflow channel is provided with a downward-opening diffuser, which is conical and has several continuously arranged turbulence teeth on its edge.

4. The anti-reverse gas distribution device as described in claim 1, characterized in that, The airflow channel is also equipped with a check valve, which is configured to automatically close when airflow stops in the airflow channel.

5. A design method for an anti-reverse gas distribution device as described in any one of claims 1 to 4, characterized in that, It includes the following steps: Step A: Select a stirring device with appropriate parameters according to the working conditions, and determine the gas flow rate Q, gas density ρ, and rated power of the motor; Step B: Detect and calculate the power loss P due to the "stripping effect" under ventilation conditions. l According to the torque power calculation formula, P l Converted to tangential resistance torque T r ; Step C: Based on the gas flow rate Q and gas density ρ from Step A, calculate the compensation torque T by setting the parameters of the axial flow impeller. d ; Step D: By adjusting the parameters of the axial flow impeller in step C, the compensating torque T is adjusted. d Counteracting tangential resistance torque T r This allows us to determine the specific design parameters of the axial flow impeller.

6. The design method of the anti-reverse gas distribution device as described in claim 5, characterized in that, In step C, assume that the gas does not rotate when it enters the axial flow impeller, i.e., V θ =0, based on the gas flow rate Q in step A, by setting the diameter d of the axial flow impeller, according to formula V z =(4×Q) / (π×d 2 ), to obtain the axial velocity V of the gas. z When the blades are configured as flat, straight blades, the airflow angle β at the blade exit is set according to formula V. θ =V z ×tanβ=(4×Q×tanβ) / (π×d 2 The circumferential velocity V of the airflow is obtained. θ When the blades are configured as helical curved blades, the pitch P is set. 螺距 Pitch P 螺距 The airflow angle β at the blade exit satisfies tanβ=P 螺距 / (π×d), according to the formula V θ =V z ×tanβ=(4×Q×tanβ) / (π×d 2 The circumferential velocity V of the airflow is obtained. θ .

7. The design method of an anti-reverse gas distribution device as described in claim 6, characterized in that, In step C, the gas density ρ is assumed to be constant, and the effective gas volume Q1 = ε × Q is set, where ε is the effective gas volume ratio, ranging from 0 to 1, and is proportional to the ratio of the top-view projected area of ​​the axial impeller to the cross-sectional area of ​​the airflow channel; based on the circumferential velocity V of the airflow... θ It has been calculated that, according to the formula F=ρ×Q1×V θ =(4×ρ×ε×Q 2 ×tanβ) / (π×d 2 ), thus obtaining the tangential force F exerted by the gas on the axial impeller.

8. The design method of the anti-reverse gas distribution device as described in claim 7, characterized in that, In step C, let the average radius r m =d / 3, which is equivalent to the effective radius of the tangential force F acting on the axial impeller; based on the calculated tangential force F of the gas acting on the axial impeller, according to formula T d =F×r m =(4×ρ×ε×Q 2 ×tanβ) / (3π×d), we get the compensation torque T d .

9. The design method of an anti-reverse gas distribution device as described in claim 8, characterized in that, In step D, different compensation torques T are calculated by adjusting the specific values ​​of three parameters: the effective air volume ratio ε, the blade outlet airflow angle β, and the axial impeller diameter d. d When the compensation torque T d Counteracting tangential resistance torque T r When determining the corresponding effective air volume ratio ε, blade outlet airflow angle β, and axial impeller diameter d, a set of effective axial impeller design parameters is established.

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