Gas Roots flowmeter

Abstract

The invention belongs to the technical field of flow measurement, and mainly relates to a gas Roots flowmeter which comprises a shell with a metering chamber, two waist wheels meshed with each other are rotationally assembled in the metering chamber, and the two waist wheels synchronously and reversely rotate. Each section, perpendicular to the rotating axis of the corresponding waist wheel, of each waist wheel is provided with two end points deviating from the rotating axis, the multiple end points on the same side form an end line, the end lines are spirally arranged around the rotating axis, and the spiral directions of the end lines on the two waist wheels are opposite. When the two waist wheels are meshed, the contact line of the two waist wheels is inclined, the waist wheels gradually enter and are gradually separated from the meshing, the meshing process is a progressive process, and the stress on the two waist wheels is gradually increased and then gradually decreased, so that the impact and vibration in the meshing process are reduced, and the noise is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of flow measurement, and mainly relates to a gas Roots flowmeter. Background Art

[0002] The gas Roots flowmeter is based on the volumetric measurement principle. There is a metering chamber in the shell of the flowmeter, and a pair of lobes that can rotate tangentially are arranged in the metering chamber. When the measured gas flows through the metering chamber, under the action of the pressure difference between the inlet and outlet, the lobes start to rotate, continuously dividing the measured gas into known single-volume parts. By calculating the number of rotations of the lobes and the quantitative volume of the metering chamber, the gas flow rate can be obtained.

[0003] However, when using the existing gas Roots flowmeter, the lobes rotate at a high speed, and the gas Roots flowmeter will generate relatively large noise, which will not only have a certain impact on the working environment, but also may cover up abnormal sounds of other equipment, which is not conducive to the fault judgment and maintenance of the equipment. Summary of the Invention

[0004] The present invention provides a gas Roots flowmeter to solve the problem that the existing gas Roots flowmeter generates relatively large noise.

[0005] To solve the above problems, the present invention adopts the following technical solutions: A gas Roots flowmeter includes a shell having a metering chamber. Two meshing lobes are rotatably assembled in the metering chamber, and the two lobes rotate synchronously and in opposite directions. Each lobe has two end points deviating from the rotation axis on each cross-section perpendicular to its rotation axis. The end points on the same side form an end line, and the end line is helically arranged around the rotation axis, and the end lines on the two lobes have opposite helical directions.

[0006] It has the following beneficial effects: When the two lobes are meshed, the contact line between the two lobes is inclined, and the lobes gradually enter and gradually disengage from the meshing. The meshing process is a progressive process, and the forces on the two lobes gradually increase from small to large and then decrease from large to small, thus reducing the impact and vibration during the meshing process, and thereby reducing the generation of noise; The two lobes are in contact at an oblique angle, which will reduce the frictional resistance, generate less heat during the synchronous reverse rotation process, and result in less energy loss.

[0007] Further, each lobe includes a rotating main body and a rotating shaft assembled on the rotating main body. The rotating shaft is coaxial with the rotation axis of the rotating main body, and the rotating shaft is rotatably assembled on the shell. By rotating the rotating shaft, the rotating main body rotates in the metering chamber.

[0008] Furthermore, a spiral scraper is provided at the end wire of the rotating body. A spiral groove is formed between the spiral scraper and the rotating body. The spiral scraper is used to scrape the impurities adhering to the inner wall of the metering chamber, so that the impurities are discharged from the spiral groove.

[0009] It has the following beneficial effects: The gas will contain impurities. By scraping the impurities sticking to the inner wall of the metering chamber with the spiral scraper, it can prevent the lobes from getting stuck during rotation.

[0010] Furthermore, a plurality of weight-reducing holes are provided on the rotating body. The plurality of weight-reducing holes are arranged circumferentially and spirally and evenly around the rotating shaft, and the weight-reducing holes are in the same spiral direction as the end wire on the same side.

[0011] It has the following beneficial effects: By setting the weight-reducing holes, the self-weight of the lobes can be reduced, so that when measuring the gas flow rate, it is more accurate; at the same time, the usage amount of the lobe material is also reduced, directly reducing the raw material cost of the gas Roots flowmeter; at the same time, the force on the lobes during rotation can be optimized, making the rotation of the lobes more uniform, smooth and better balanced.

[0012] Furthermore, a coaxial synchronous gear is provided at one end of each rotating shaft. The two synchronous gears mesh with each other to drive the two lobes to rotate synchronously and in opposite directions.

[0013] It has the following beneficial effects: Through the two synchronous gears, the two lobes rotate synchronously in reverse, ensuring that the gas can be continuously divided into known single volume parts. In this way, by calculating the number of rotations of the lobes and the quantitative volume of the metering chamber, the gas flow rate can be obtained.

[0014] Furthermore, a first protective cover is provided on the housing. The first protective cover is used to cover the two synchronous gears, and an oil filling port for pouring lubricating oil is provided on the first protective cover.

[0015] It has the following beneficial effects: The first protective cover can protect the two synchronous gears from various factors in the external environment; at the same time, lubricating oil is added to the first protective cover through the oil filling port, making the rotation of the two synchronous gears smoother and ensuring the accuracy during measurement.

[0016] Furthermore, an oil slinger is provided at one end of one of the rotating shafts and is located inside the first protective cover. The oil slinger and the two synchronous gears are on the same side. The oil slinger is used to throw lubricating oil towards the two meshing synchronous gears.

[0017] It has the following beneficial effects: Using the oil slinger to throw lubricating oil can make the two synchronous gears more fully lubricated, so that the rotation of the two synchronous gears is smoother and ensures the accuracy of the measurement.

[0018] Further, a second protective cover is provided on the housing, and the second protective cover is used to cover the other end of the rotating shaft.

[0019] It has the following beneficial effects: The second protective cover protects the other end of the rotating shaft from various factors in the external environment.

[0020] Further, a photoelectric transceiver sensor is provided on the second protective cover, and the photoelectric transceiver sensor is used to collect information on the number of rotations of the rotating shaft.

[0021] It has the following beneficial effects: In the prior art, a magnetic coupling is often used, while in this application, a photoelectric transceiver sensor is used to collect information on the number of rotations of the rotating shaft. The photoelectric transceiver sensor uses the principle of photoelectric conversion and there is no magnetic vortex resistance. It can effectively detect both small-flow low-frequency signals and large-flow high-frequency signals, and there are no problems such as signal distortion and missed detection, greatly improving the comprehensive performance of the gas Roots flowmeter and extending its service life.

[0022] Further, an inlet and an outlet are provided on the housing.

[0023] It has the following beneficial effects: The inlet is used for gas to enter the metering chamber, and the outlet is used for gas to exit the metering chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become readily understood. In the drawings, several embodiments of the present invention are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 is a schematic diagram of the internal structure of the present invention; Figure 2 is a schematic diagram of the meshing of two lobe wheels; Figure 3 is Figure 2 the right view of; Figure 4 is Figure 3 the sectional view taken along the A-A direction in; Figure 5 is a schematic diagram of the lobe wheel structure; Figure 6 is Figure 5 the enlarged view at B in;

[0025] Description of the reference numerals: 1, lobe wheel; 2, rotating body; 3, rotating shaft; 4, weight reduction hole; 5, spiral scraper; 6, spiral groove; 7, housing; 8, metering chamber; 9, synchronous gear; 10, first protective cover; 11, oil filling port; 12, oil throwing piece. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0027] The following specifically introduces various non-limiting implementation manners of the present invention. The number of any element in the drawings is for illustration rather than limitation, and any naming is only for distinction and does not have any limiting meaning. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0028] As Figure 1 shown, a gas Roots flowmeter includes a housing 7 having a metering chamber 8. Except for an inlet for gas to enter the metering chamber 8 and an outlet for gas to exit the metering chamber 8 on the housing 7, the metering chamber 8 is sealed.

[0029] In this embodiment, as Figures 1 - 4 shown, two meshing lobes 1 are rotatably assembled in the metering chamber 8. The two lobes 1 rotate synchronously and in opposite directions. During the rotation of the two lobes 1, a known single volume portion can be formed with the inner wall of the metering chamber 8. By calculating the number of rotations of the lobes 1 and the quantitative volume of the metering chamber 8, the gas flow rate can be obtained. How to calculate the gas flow rate is prior art and will not be elaborated in this embodiment.

[0030] Each lobe 1 has two end points deviating from the rotation axis on each cross-section perpendicular to its rotation axis. The multiple end points on the same side form an end line. The end line is arranged in a spiral around the rotation axis, and the spiral directions of the end lines on the two lobes 1 are opposite. In this embodiment, the spiral angle of the end line is greater than 0° and less than or equal to 360°.

[0031] In this embodiment, the cross-sections are distributed along the extension direction of the rotation axis. The end point is the point farthest from the rotation axis.

[0032] When the two lobes 1 are meshed, the contact line between the two lobes 1 is inclined. The lobes 1 gradually enter and gradually disengage from the meshing. The meshing process is a gradual process. The forces on the two lobes 1 gradually increase from small to large and then decrease from large to small, thus reducing the impact and vibration during the meshing process, thereby reducing the generation of noise; at the same time, the two lobes 1 are in contact at an oblique angle, which will reduce the frictional resistance, generate less heat during the synchronous reverse rotation process, and have less energy loss, which is beneficial to improving the service life of the gas Roots flowmeter.

[0033] In this embodiment, each lobe wheel 1 includes a rotating body 2 and a rotating shaft 3 assembled on the rotating body 2. The rotating shaft 3 is coaxial with the rotation axis of the rotating body 2. The rotating shaft 3 is rotatably assembled on the housing 7. By rotating the rotating shaft 3, the rotating body 2 rotates in the metering chamber 8.

[0034] As Figure 5 , Figure 6 shown, a spiral scraper 5 is provided at the end line of the rotating body 2, and the spiral scraper 5 extends along the extending direction of the end line. A spiral groove 6 is formed between the spiral scraper 5 and the rotating body 2. The spiral scraper 5 is used to scrape the impurities adhering to the inner wall of the metering chamber 8, so that the impurities are discharged from the spiral groove 6. There will be impurities in the gas. By scraping the impurities adhering to the inner wall of the metering chamber 8 with the spiral scraper 5, it can prevent the lobe wheel 1 from jamming during rotation.

[0035] In this embodiment, a plurality of weight reduction holes 4 are provided on the rotating body 2. The plurality of weight reduction holes 4 are arranged helically and evenly in the circumferential direction around the rotating shaft 3, and the weight reduction holes 4 are in the same spiral direction as the end line on the same side. By providing the weight reduction holes 4, the self-weight of the lobe wheel 1 can be reduced, so that when measuring the gas flow rate, it is more accurate; at the same time, the amount of material used for the lobe wheel 1 is also reduced, directly reducing the raw material cost of the gas Roots flowmeter; at the same time, the force on the lobe wheel 1 during rotation can be optimized, making the rotation of the lobe wheel 1 more uniform and smooth, and the balance better. At the same time, the weight reduction holes 4 can play a certain role in heat dissipation. The weight reduction holes 4 can increase the air circulation, contribute to heat dissipation, improve the heat dissipation performance of the gas Roots flowmeter, and prevent the gas Roots flowmeter from being affected by overheating in terms of performance or service life. And the weight reduction holes 4 can be used as process holes to facilitate the processing process, facilitate the processing operation and ensure the processing accuracy. At the same time, during assembly, the weight reduction holes 4 may also play an auxiliary role in assembly, such as facilitating the worker to reach in or facilitating the insertion of installation tools.

[0036] As Figure 1 shown, a coaxial synchronous gear 9 is provided at one end of each rotating shaft 3. The two synchronous gears 9 are meshed with each other to drive the two lobe wheels 1 to rotate synchronously and in opposite directions. The two synchronous gears 9 in this embodiment have the same specifications and are meshed with each other. During rotation, the rotation directions are opposite. When one synchronous gear 9 rotates, through the meshing of teeth, the other synchronous gear 9 connected to it rotates at the same angular velocity or according to a specific transmission ratio, so as to achieve synchronous motion. Through the two synchronous gears 9, the two lobe wheels 1 rotate synchronously in reverse, ensuring that the gas can be continuously divided into known single volume parts. In this way, by calculating the number of rotations of the lobe wheel 1 and the quantitative volume of the metering chamber 8, the gas flow rate can be obtained.

[0037] The tooth profile of the synchronous gear 9 is usually carefully designed with high precision and accuracy. The tooth profile in this embodiment can be an involute tooth profile, an arc tooth profile, etc. These tooth profiles can ensure uniform force distribution during the meshing process of the synchronous gear 9, reduce wear and noise, and improve the transmission efficiency.

[0038] The synchronous gear 9 in this embodiment is made of high-strength, wear-resistant, and corrosion-resistant materials, such as high-quality carbon steel, alloy steel, stainless steel, etc.

[0039] In other embodiments, materials such as copper alloys and engineering plastics can also be used.

[0040] The manufacturing process of the synchronous gear 9 in this embodiment includes multiple links such as forging, cutting, grinding, and heat treatment. Through these processes, the dimensional accuracy, geometric tolerance, and surface quality of the synchronous gear 9 can be ensured, thereby improving the transmission performance and service life of the synchronous gear 9.

[0041] In this embodiment, as Figure 1 shown, a first protective cover 10 is provided on the housing 7. The first protective cover 10 is used to cover the two synchronous gears 9, and an oil filling port 11 for pouring lubricating oil is provided on the first protective cover 10. The first protective cover 10 can protect the two synchronous gears 9 from various factors in the external environment; at the same time, lubricating oil is added into the first protective cover 10 through the oil filling port 11, making the rotation of the two synchronous gears 9 smoother and ensuring the accuracy during measurement.

[0042] The lubricating oil in this embodiment is a liquid lubricant used on the synchronous gear 9 to reduce friction and protect the synchronous gear 9. It mainly plays roles such as lubrication, cooling, rust prevention, cleaning, sealing, and buffering. The lubricating oil can form an oil film between the surfaces of the two relatively moving synchronous gears 9, reducing the direct contact between the surfaces of the synchronous gear 9, thereby reducing the friction coefficient and wear. The lubricating oil plays a lubricating role to ensure the normal operation of the two synchronous gears 9; at the same time, the oil film isolates air, moisture, and corrosive substances, preventing the synchronous gear 9 from rusting and corroding.

[0043] When the synchronous gear 9 is subjected to impact loads, the lubricating oil can play a buffering role, reducing the impact between the two synchronous gears 9 and protecting the synchronous gear 9.

[0044] In this embodiment, as Figure 1As shown in the figure, an oil slinger 12 located within the first protective cover 10 is provided at one end of a rotating shaft 3. The oil slinger 12 and the two synchronous gears 9 are on the same side. The oil slinger 12 is used to throw lubricating oil towards the two meshing synchronous gears 9. The oil slinger 12 rotates together with the rotating shaft 3. During the rotation process, the oil slinger 12 can collide with and scrape the lubricating oil, and throw the lubricating oil away, so that the parts of the synchronous gears 9 that cannot directly contact the lubricating oil can be lubricated. In this way, the two synchronous gears 9 can be lubricated more fully, making the rotation of the two synchronous gears 9 smoother and ensuring the accuracy of the measurement.

[0045] As Figure 1 shown, a second protective cover is provided on the housing 7. The second protective cover is used to cover the other end of the rotating shaft 3. The second protective cover protects the other end of the rotating shaft 3 from various factors in the external environment.

[0046] In this embodiment, the first protective cover 10 and the second protective cover can protect the covered components, preventing the influence of dust, oil, moisture, iron filings, high temperature, etc. on the protected object. At the same time, they can also reduce noise and vibration, ensure safety, and extend the service life of the equipment.

[0047] In this embodiment, a photoelectric transceiver sensor is provided on the second protective cover. The photoelectric transceiver sensor is used to collect information on the number of rotations of the rotating shaft 3.

[0048] In the prior art, a magnetic coupler is often used. In this embodiment, a photoelectric transceiver sensor is used to collect information on the number of rotations of the rotating shaft 3. The photoelectric transceiver sensor uses the principle of photoelectric conversion and has no magnetic vortex resistance. It can effectively detect both small-flow low-frequency signals and large-flow high-frequency signals, and there are no signal distortion and missed detection phenomena, greatly improving the comprehensive performance of the gas roots flowmeter, enhancing the accuracy, and extending the service life.

[0049] In this embodiment, the photoelectric transceiver sensor, namely the photoelectric sensor, is a device that uses the principle of the photoelectric effect to convert optical signals into electrical signals.

[0050] Based on the photoelectric effect, when an object is irradiated by light, its internal electrons absorb the photon energy and change their state, causing a change in its own electrical properties. The specific process is that the transmitter aims the light beam at the target. The light beam generally comes from semiconductor light sources such as light-emitting diodes (LEDs), laser diodes, and infrared emitting diodes, and the light beam is continuously emitted or the pulse width is changed. The receiver consists of a photodiode, a phototransistor, and a photovoltaic cell, and optical elements such as lenses and apertures are installed in front of it to collect the reflected light and convert it into an electrical signal, which is then sent to the detection circuit. The detection circuit can filter out the effective signal and apply it.

[0051] Among them, the transmitter usually includes a light source and a condenser lens assembly, which is used to emit a light beam to irradiate the target object and generate reflected light. Common light sources include light-emitting diodes, laser diodes, and infrared diodes. The condenser lens assembly can adjust the beam focus, improve the irradiation effect, and increase the light brightness.

[0052] The receiver usually consists of a photodiode, a phototransistor, and a photovoltaic cell, which is used to collect the reflected light, convert it into an electrical signal, and send it to the detection circuit. The photodiode utilizes the photoelectric effect of the PN junction to generate current when irradiated by light, featuring high-speed response and high sensitivity. The phototransistor utilizes the light irradiation of the PN junction between the base and the emitter to trigger current changes, having higher gain and sensitivity.

[0053] The detection circuit is responsible for converting the optical signal into an electrical signal and performing processing such as amplification, filtering, and transformation on the electrical signal in order to obtain and analyze information related to the optical signal. Common detection circuits include a comparison circuit and a time-difference circuit. The comparison circuit compares the electrical signal obtained by the receiver with a preset threshold to determine whether the target object exists; the time-difference circuit calculates the distance between the target object and the photoelectric sensor using the transmission time of the reflected light.

[0054] The Roots gas flowmeter in this embodiment 1. Product Features 1.1 High precision: Advanced machining and surface treatment processes, wear-free rotation, non-contact sealing and other technologies ensure the high precision of the Roots gas flowmeter. Generally, the measurement accuracy is 1.5 level, and the standard meter with special requirements can reach 1.0 level.

[0055] 1.2 Wide range ratio: It has a very wide application range. The range ratio can generally reach 20:1 or even higher, which can adapt to the gas measurement of different flow ranges without the need to frequently replace the instrument.

[0056] 1.3 Small pressure loss: Generally less than 0.5 kPa, and the minimum is 0.08 kPa, which helps to reduce the energy consumption of the pipeline system and reduce the operating cost.

[0057] 1.4 Intelligence: It can realize functions such as automatic calibration, data storage, and remote communication, improving the convenience and accuracy of measurement, and facilitating centralized management and remote monitoring.

[0058] 1.5 Long service life: After 15 years of use under clean gas conditions, the measurement accuracy basically remains the original factory accuracy. The good oil lubrication and non-contact rotation of the lobes also extend its service life.

[0059] 1.6. Easy installation: No straight pipe sections are required before and after the gas Roots flowmeter, and it can be installed in narrow environments. There are various installation forms, including vertical installation of the inlet and outlet and horizontal installation of the inlet and outlet. When installed vertically, the gas flow direction is from top to bottom, and the lobed impellers have the ability to self-clean impurities in the pipeline.

[0060] 2. Application fields 2.1. Petrochemical industry: Widely used in the flow measurement of gases such as natural gas, liquefied petroleum gas, and hydrogen to ensure the stability and safety of the production process, improve product quality and economic benefits.

[0061] 2.2. Environmental protection monitoring: Used to monitor the emission volume and concentration of industrial waste gases, helping enterprises comply with environmental protection regulations, reduce pollution emissions, and achieve sustainable development.

[0062] 2.3. Energy metering: Can measure the consumption of energy such as natural gas and coal gas, assisting enterprises in optimizing the energy use structure, reducing energy costs, and improving energy utilization efficiency.

[0063] 2.4. Public utilities: In the fields of urban gas supply, water treatment plants, etc., used to measure the supply volume and consumption volume of gases. Through remote communication and data transmission, functions such as automatic meter reading, real-time monitoring, and data analysis are realized, improving management efficiency and user satisfaction.

[0064] The working process of the present invention is as follows: The gas to be measured enters the metering chamber 8 from the inlet, pushing the two lobed impellers 1 to rotate synchronously in opposite directions. Then, the gas to be measured exits from the outlet and leaves the metering chamber 8.

[0065] Among them, during the rotation of the two lobed impellers 1, the optoelectronic transceiver sensor records the number of rotations of the lobed impellers 1. By calculating the number of rotations of the lobed impellers 1 and the quantitative volume of the metering chamber 8, the gas flow rate can be obtained.

Claims

1. A gas Roots flowmeter, comprising a housing having a metering chamber, wherein two mutually meshing waist wheels are rotatably mounted in the metering chamber, and the two waist wheels rotate synchronously in opposite directions, characterized in that: Each of the waist wheels has two endpoints facing away from the rotation axis on each section perpendicular to the rotation axis, and multiple endpoints on the same side constitute end lines, which are spirally arranged around the rotation axis, and the spiral directions of the end lines on the two waist wheels are opposite.

2. A gas Roots flowmeter according to claim 1, characterized in that: Each of the waist wheels comprises a rotating body and a rotating shaft mounted on the rotating body, wherein the rotating shaft is coaxial with the rotating axis of the rotating body, and the rotating shaft is rotatably mounted on the shell, and the rotating body is rotated in the metering chamber by the rotation of the rotating shaft.

3. A gas Roots flowmeter according to claim 2, characterized in that: A spiral scraper is provided at the end line of the rotating body, and a spiral groove is formed between the spiral scraper and the rotating body. The spiral scraper is used to scrape impurities attached to the inner wall of the metering chamber so that the impurities are discharged from the spiral groove.

4. A gas Roots flowmeter according to claim 3, characterized in that: The rotating body is provided with a plurality of weight-reducing holes, which are evenly arranged in a spiral around the rotating shaft, and the weight-reducing holes are in the same spiral direction as the end line on the same side.

5. A gas Roots flowmeter according to claim 4, characterized in that: A coaxial synchronous gear is provided at one end of each rotating shaft, and the two synchronous gears are meshed with each other to drive the two waist wheels to rotate synchronously in opposite directions.

6. A gas Roots flowmeter according to claim 5, characterized in that: The housing is provided with a first protective cover, which is used to cover the two synchronous gears. The first protective cover is provided with an oil filling port for filling lubricating oil.

7. A gas Roots flowmeter according to claim 6, characterized in that: An oil-slinging plate located in the first protective cover is provided on one end of one of the rotating shafts. The oil-slinging plate and the two synchronous gears are on the same side. The oil-slinging plate is used to throw lubricating oil to the two meshing synchronous gears.

8. A gas Roots flowmeter according to claim 7, characterized in that: The shell is provided with a second protective cover, and the second protective cover is used for covering the other end of the rotating shaft.

9. A gas Roots flowmeter according to claim 8, characterized in that: The second protective cover is provided with a photoelectric transceiver sensor, and the photoelectric transceiver sensor is used to collect information about the number of revolutions of the rotating shaft.

10. A gas Roots flowmeter according to any one of claims 1 to 9, characterized in that: The shell is provided with an inlet and an outlet.

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