Oval Gear Flow Meter Assembly Method

Abstract

This invention discloses a method for assembling a rotary flow meter, characterized by the following steps: Step 1: Assembling the rotary wheels: One end of the central shaft hole of each rotary wheel is coaxially fixedly connected to one end of a short shaft, and a bearing is fitted onto the other end of the short shaft; the other end of the central shaft hole of each rotary wheel is coaxially fixedly connected to one end of a long shaft, and then assembled with the bearing; the other section of the long shaft, from the outside to the inside along the axial direction, consists of a locking nut connection section, a synchronous pulley mounting section, an adjusting nut connection section, and a bearing mounting section, with the bearing mounting section housing the bearing; the bearing fitted on the short shaft is installed into the corresponding mounting groove on the first end cover of the rotary flow meter housing; the second end cover is then fastened to the housing with screws, allowing the adjusting nut connection section and the bearing mounting section of the long shaft to extend outside the second end cover; an adjusting nut is fitted onto the adjusting nut connection section of the long shaft; Step 2: Assembling the synchronous gears: Meshing synchronous gears are fitted into the synchronous pulley mounting sections of the long shafts of the two rotary wheels.

Description

[0001] This application is a divisional application of application number 202210838128X, application date 2022.07.17, entitled "Inlet structure, rotary flow meter and assembly method thereof". Technical Field

[0002] This invention belongs to the field of rotary flow meters, and specifically relates to a method for assembling a rotary flow meter. Background Technology

[0003] A Roots flow meter is a rotor-type positive displacement flow meter, also known as a Roots flow meter. Inside the flow meter housing is a metering chamber containing a pair of tangentially rotating Roots wheels. Roots flow meters are metering instruments used for continuous or intermittent measurement of the flow rate of media (gas or liquid) in pipelines. They are characterized by high accuracy, high reliability, light weight, long service life, and ease of installation and use.

[0004] The prior art patent document CN113188625A discloses a rotary flow meter. This technical solution includes a housing with symmetrically arranged flow guide ports on both sides. A bottom cover is fixedly installed at one end of the housing, and a top cover is fixedly installed at the other end. A flow indicator is fixedly installed on the outer side of the top cover. A metering chamber is formed inside the housing, and two rotating shafts with their ends extending into the bottom and top covers respectively are movably installed inside the metering chamber. A rotary wheel is fixedly installed on the outer ring of the rotating shafts. A transmission cavity is formed inside the top cover, and a pair of meshing synchronous gear rings are movably installed inside the transmission cavity. A mounting sleeve shaft is movably installed at the center of the synchronous gear rings inside the transmission cavity. The top cover is located at the center of the synchronous gear rings. A magnetic coupler is movably installed between the gear ring and the flow display. A limit pin is movably installed inside the bottom cover at the end face of the rotating shaft. A clamping block is fixedly engaged on the outside of the limit pin. A spiral end cap is threaded onto the outside of the clamping block. A transmission gear column is movably installed in the transmission cavity near the magnetic coupler between the inner ring of the synchronous gear ring and the outer ring of the mounting sleeve shaft. A driven block is uniformly fixedly installed in a ring shape on the inner ring of the synchronous gear ring. A sleeve block is fixedly connected to one side of the driven block. A rotating block is uniformly fixedly installed in a ring shape on the outer ring of the mounting sleeve shaft. The number of rotating blocks and driven blocks is the same and they are distributed alternately. A movable groove is opened inside the rotating block to movably engage with the sleeve block. A slot is opened on the side of the mounting sleeve shaft near the housing to movably engage with the rotating shaft.

[0005] However, the above-mentioned rotary flow meter still has the following shortcomings:

[0006] After the medium being measured enters through the inlet on the casing, it diffuses outwards within the metering chamber, reducing the rotational response of the rotary wheel and thus affecting the metering accuracy. It also fails to prevent the flow of impurities.

[0007] Based on this, the applicant is considering designing an assembly method for a rotary flow meter that can improve metering accuracy. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide an assembly method for a rotary flow meter that can improve metering accuracy.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] The assembly method of the rotary flow meter includes the following steps:

[0011] Step 1: Assemble the waist wheel:

[0012] a. Fix one end of the central shaft hole of each lap girder to one end of the short shaft in the same axial direction, and install a bearing on the other end of the short shaft; fix the other end of the central shaft hole of each lap girder to one end of the long shaft in the same axial direction, and then assemble and connect it with the bearing. The other section of the long shaft consists of a synchronous pulley mounting section, an adjusting nut connecting section and a bearing mounting section along the axial direction from the outside to the inside. The bearing mounting section is fitted with a bearing.

[0013] b. Install the bearing mounted on the short shaft into the corresponding mounting groove on the first end cover of the housing of the rotary flow meter; then fasten the second end cover to the housing with screws so that the adjusting nut connecting section of the long shaft and the bearing mounting section extend out of the second end cover; an adjusting nut is fitted on the adjusting nut connecting section of the long shaft.

[0014] Step 2: Assemble the synchronizing gears:

[0015] Meshing synchronous gears are fitted into the synchronous pulley mounting sections of the long shafts of the two lap pulleys;

[0016] Unlike existing rotary flow meters that use a straight-through (cylindrical orifice channel) pipe as the air inlet structure, the inlet structure of this invention has the following advantages:

[0017] 1. The aforementioned guide surface is installed at the inlet orifice of the rotary flowmeter. This guide surface allows the flowing medium to converge and be directed towards the junction between a pair of rotary impellers in the flowmeter. This effectively prevents the incoming medium (airflow or liquid flow) from spreading outwards after entering the metering chamber. Instead, it converges and is directed towards the midpoint between the two rotary impeller rotors, allowing the rotors to obtain optimal driving torque and respond more quickly and instantaneously to the flow of the medium, thus improving the metering accuracy of the rotary flowmeter.

[0018] 2. The above-mentioned guide surface can also form a blocking surface to block impurities, which can more effectively prevent impurities from entering the cavity of the rotary flow meter, better avoid problems such as rotary wheel jamming, and help improve the reliability of long-term use. Attached Figure Description

[0019] Figure 1 This is a schematic diagram (top view) of the structure of the rotary flow meter of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the rotary flow meter of the present invention (viewed from below).

[0021] Figure 3 This is a schematic diagram of the housing structure in the rotary flowmeter of the present invention.

[0022] Figure 4 for Figure 3 Sectional view of line II

[0023] Figure 5 This is a top view of the rotary flow meter of the present invention.

[0024] Figure 6 for Figure 5 Sectional view along line II-II

[0025] Figure 7 for Figure 5 Sectional view along line III-III

[0026] Figure 8 for Figure 7 Enlarged view of the area within the dashed box

[0027] Figure 9 This is a schematic diagram of the long shaft in the rotary flowmeter of the present invention.

[0028] Figure 10 This is a schematic diagram of the interlocking wheel clearance detection in the interlocking wheel flowmeter assembly method of the present invention.

[0029] Figure 11 This is a schematic diagram of the roller clearance adjustment in the roller flowmeter assembly method of the present invention.

[0030] Figure 12 This is a schematic diagram of the interlocking wheel clearance detection in the interlocking wheel flowmeter assembly method of the present invention.

[0031] Figure 13 This is a schematic diagram of the roller clearance adjustment in the roller flowmeter assembly method of the present invention.

[0032] The diagram is marked as follows:

[0033] 10. Housing: 1011 Temperature sensor port, 1012 Pressure tap port

[0034] 11 Upper guide block

[0035] 12 Lower Guide Blocks

[0036] 13 guide surfaces

[0037] 14-way gyroscope

[0038] 15 short axis

[0039] 16 Long Shaft: 161 Locking Nut Connecting Section, 162 Synchronous Pulley Mounting Section, 163 Adjusting Nut Connecting Section, 164 Bearing Set Section

[0040] 17 elastic gaskets

[0041] 18 Adjusting Screws

[0042] 19 bearings

[0043] 20 Synchronous Gears

[0044] 21 Locking Nut

[0045] 22 feeler gauge

[0046] 23 Reference Lobe Wheel

[0047] 24 Adjustable waist wheel

[0048] 25 strip-shaped blocking blocks Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings.

[0050] In practical implementation: such as Figures 1 to 13 As shown,

[0051] The inlet structure includes a guide surface provided at the orifice of the inlet of the rotary flowmeter, the guide surface enabling the flowing medium to converge and be directed toward the junction between a pair of rotary impellers in the rotary flowmeter.

[0052] Among them, an upper guide block is integrally formed and connected to the inner upper side of the inlet orifice, and the upper side and the left and right sides of the upper guide block are sealed to the inner side of the orifice.

[0053] A lower guide block is integrally formed and connected to the inner lower side of the inlet orifice, and the lower side and the left and right sides of the lower guide block are sealed to the inner side of the orifice.

[0054] The windward surfaces of the upper and lower guide blocks constitute the guide surface.

[0055] The lower end face of the upper guide block is spaced apart from the upper end face of the lower guide block to form a converging guide channel, which is used to allow the medium flow to converge and be directed toward the junction between a pair of rotary impellers in the rotary impeller flow meter.

[0056] The aforementioned upper and lower guide blocks are integrally formed with the orifice, that is, integrally formed with the housing of the rotary flowmeter. This allows for the integral forming of the housing, upper and lower guide blocks through casting, reducing the difficulty of machining and setting up the upper and lower guide blocks.

[0057] At the same time, since the upper and lower guide blocks are only arranged in the inlet orifice and the amount of material used is small, it is easy to effectively control costs and avoid increasing product manufacturing costs due to improved metering accuracy.

[0058] In addition, the structural design of the upper and lower guide blocks can further enhance the structural strength of the inlet and the housing of the rotary flow meter, and further improve the explosion-proof performance.

[0059] In summary, using the aforementioned upper and lower guide blocks improves metering accuracy at a lower cost, resulting in better economic benefits and practical value.

[0060] The upper guide block and the lower guide block are mirror-symmetrical in the vertical direction of the rotary flow meter; the distance between the lower end face of the upper guide block and the upper end face of the lower guide block accounts for 60% to 65% of the orifice diameter of the inlet.

[0061] This effectively prevents impurities in the gas pipeline from entering the flow meter.

[0062] By using upper and lower guide blocks with mirror symmetry, they can work together to form the optimal converging and guiding effect, better avoid jet collisions that reduce the kinetic energy of the medium flow, and ensure the achievement of higher metering accuracy.

[0063] At the same time, by using the above-mentioned ratio range of spacing to orifice diameter, we can avoid adverse effects on the maximum flow rate and achieve higher metering accuracy while setting the maximum flow rate.

[0064] The upper guide block and the lower guide block each have a shape that is thinner in the middle and gradually thickens towards both ends in the axial direction along the waist wheel; and the windward surface of the upper guide block and the lower guide block are both arc-shaped surfaces, the radius of the arc-shaped surface gradually decreases inward along the axial direction of the inlet orifice.

[0065] The use of the aforementioned upper and lower guide blocks has the advantages of high strength and reliable structure. At the same time, the windward surfaces of the upper and lower guide blocks together form a "trumpet-shaped" (or "funnel-shaped") surface structure, which plays a better role in converging and guiding the flow.

[0066] The upper guide block and the lower guide block are both located at the innermost end of the inlet orifice.

[0067] In this way, the depth of the orifice can be fully utilized, the travel distance of impurities within the orifice can be extended, the kinetic energy of the impurities can be reduced, and the optimal impurity blocking effect can be achieved by using the upper and lower guide blocks.

[0068] At the same time, based on the fact that "both the upper and lower guide blocks are located at the innermost end of the inlet orifice", they are closest to a pair of lobed rotors, thus achieving the best convergence and guiding effect and realizing the best metering accuracy improvement effect.

[0069] The rotary flow meter has the inlet structure described above.

[0070] The rotary flow meter also includes an outlet structure, which is mirror-symmetrical to the inlet structure.

[0071] By adopting the above-mentioned mirror-symmetrical outlet and inlet structures, the metering accuracy can be improved, and the volume of the metering chamber can be increased without increasing the outer dimensions and internal volume of the rotary flow meter housing.

[0072] The rotary flow meter structure using this technical solution can achieve bidirectional metering, namely, left inlet and right outlet, or right inlet and left outlet, with a metering accuracy of 0.5 class, which is far higher than the 1.5 class metering accuracy of other ordinary flow meters.

[0073] Temperature measuring holes and pressure tapping holes are provided at both the inlet and outlet.

[0074] This allows for bidirectional air intake and bidirectional temperature and pressure measurement.

[0075] The temperature measuring port and pressure tap structure can be installed using plugs or corresponding sensors, making it highly versatile.

[0076] The axis of the pressure tap structure should be perpendicular to the axis of the measuring tube, with a diameter of (3-12) mm, and the length of the pressure tap should be at least equal to the diameter. The measurement error of the pressure gauge used should have an impact on the calibration results within 5% of the maximum permissible error of the flowmeter.

[0077] The temperature sensing orifice structure allows the temperature sensor to be positioned in the middle of the inlet flange diameter, ensuring the temperature measured is the center temperature of the fluid and guaranteeing the accuracy of temperature acquisition.

[0078] The assembly method of the rotary flow meter includes the following steps:

[0079] Step 1: Assemble the waist wheel:

[0080] a. Fix one end of the central shaft hole of each lap girder to one end of the short shaft in the same axial direction, and install a bearing on the other end of the short shaft; fix the other end of the central shaft hole of each lap girder to one end of the long shaft in the same axial direction, and then assemble and connect it with the bearing. The other section of the long shaft consists of a synchronous pulley mounting section, an adjusting nut connecting section and a bearing mounting section along the axial direction from the outside to the inside. The bearing mounting section is fitted with a bearing.

[0081] b. Install the bearing mounted on the short shaft into the corresponding mounting groove on the first end cover of the housing of the rotary flow meter; then fasten the second end cover to the housing with screws so that the adjusting nut connecting section of the long shaft and the bearing mounting section extend out of the second end cover; an adjusting nut is fitted on the adjusting nut connecting section of the long shaft.

[0082] Step 2: Assemble the synchronizing gears:

[0083] Synchronous gears that mesh with each other are fitted into the synchronizing pulley mounting section of the long shaft of the two lobes.

[0084] During implementation, two pairs of disc springs are mounted in parallel on the long shaft between the bearing mounted on the long shaft and the adjacent lobed wheel rotor. The cooperation between the two pairs of disc springs and the adjusting nut can adjust the bearing on the long shaft side and the end face of the lobed wheel to have a reasonable gap to prevent the bearing from jamming and ensure the reliability of rotation measurement.

[0085] The procedure for turning the adjusting nut is as follows:

[0086] Mark the upper position of the rotary wheel on the adjusting nut and the long shaft with a waterproof marker;

[0087] Rotate the adjusting nut until the swivel wheel and the inside of the inner end cap just touch; mark the lower position of the swivel wheel on the long shaft;

[0088] Then mark the middle position of the waist wheel;

[0089] Rotate the nut to the middle position, which will create a reasonable gap between the waist wheel and the rear cover and inner end cover, allowing the waist wheel to move up and down.

[0090] In step a of "Step 1, assembling the waist wheel":

[0091] A threaded hole is provided on the axial outer end face of the short shaft. An adjusting screw with an elastic washer is used. The outer edge of the elastic washer abuts against the axial outer end face of the bearing. The outer thread surface of the adjusting screw is coated with thread glue and screwed into the threaded hole.

[0092] Twist the adjusting screw until the screw head presses against the elastic washer, then continue to rotate it approximately 270 degrees in the tightening direction.

[0093] By using the threaded hole, elastic washer, and adjusting screw at the rear axle end, as well as the torsion assembly method of the adjusting screw, a certain gap can be maintained between the lap wheel, the rear axle, and the bearing. This prevents the lap wheel from pressing against the bearing, avoids the bearing from seizing, and ensures that the bearing can rotate normally for a long time.

[0094] At the same time, applying a small amount of thread-locking adhesive to the external thread surface of the adjusting screw before assembly can prevent the adjusting screw from loosening under high-speed operation of the bearing, thus better ensuring the long-term reliability of the adjusting screw in adjusting the aforementioned clearance.

[0095] During implementation, before assembling the short shaft bearing into the mounting slot, apply grease to both the short shaft and the inner and outer rings of the bearing for lubrication. This effectively reduces friction, minimizes the rapid temperature rise caused by high-speed bearing operation, and improves reliability.

[0096] The assembly contact surface between the outer side of the synchronous pulley mounting section of the long shaft and the inner side of the synchronous gear is a tapered surface.

[0097] The second step, assembling the synchronizing gears, also includes the following steps:

[0098] a. Gap detection:

[0099] Select a feeler gauge with the corresponding thickness according to the maximum thickness of the design. Use the feeler gauge to insert into the gap between the lap rollers and between the lap rollers and the outer shell. If the feeler gauge can pass through, the gap meets the design requirements.

[0100] When the feeler gauge cannot pass through the gap between a pair of rotary wheels, proceed with step b below;

[0101] b. Adjustment of the distance between the waist rollers:

[0102] When the feeler gauge cannot pass through the gap between a pair of rollers, one of the rollers is regarded as the reference roller and the other as the adjustment roller.

[0103] Manually rotate the reference waist wheel by 90 degrees until it is in the same rotational angle as the reference waist wheel and in contact with the reference waist wheel.

[0104] A strip-shaped blocking block is inserted into the machine housing through the inlet or outlet and is positioned between the reference cam and the machine housing to block the reference cam.

[0105] Use a wrench to turn the locking nut at the outermost end of the long shaft corresponding to the waist wheel clockwise. This increases the distance between the two waist wheels by using the taper of the tapered surface that mates with the synchronous gear, until a feeler gauge can pass through.

[0106] The aforementioned "the assembly contact surface between the outer side of the synchronous pulley mounting section of the long shaft and the inner side of the synchronous gear is a tapered surface" means that the long shaft and the synchronous gear are provided with mutually tapered shapes, which can avoid interference jamming of the synchronous gear and facilitate the assembly and disassembly of the synchronous gear.

[0107] When using the above assembly method: Assemble the gears by clamping a feeler gauge between the two sprockets using the thickness of the gauge. Simultaneously, use the feeler gauge to check the gaps between the sprockets and between the sprockets and the outer casing. Ensure the gaps meet the requirements. When assembling the synchronizing gears, use a plastic block (strip-shaped stop block) to block the sprockets. Then, insert a feeler gauge on the other side and press down on the sprockets by hand according to the gap direction, applying appropriate torque to secure them.

[0108] The clearance of the waist wheel assembly is adjusted as follows:

[0109] like Figure 9 If the positional clearance is small, rotate it 90° to... Figure 10 Position and lock the waist wheel, then tighten it with the appropriate torque;

[0110] like Figure 11 If the positional clearance is small, rotate it 90° to... Figure 12 Position and lock the waist wheel in place, then tighten it again with the appropriate torque.

[0111] The above are merely preferred embodiments of the present invention. It should be noted that any modifications and improvements made by those skilled in the art without departing from the present technical solution should also be considered to fall within the scope of protection claimed in this claim.

Claims

1. A method for assembling an oval-shaped flow meter, characterized in that: Includes the following steps: Step 1: Assemble the waist wheel: a. One end of the central shaft hole of each waist wheel is coaxially fixedly connected to one end of the short shaft, and the other end of the short shaft is fitted with a bearing; the other end of the central shaft hole of each waist wheel is coaxially fixedly connected to one end of the long shaft and then assembled with the bearing. The other section of the long shaft consists of a locking nut connection section, a synchronous pulley mounting section, an adjusting nut connection section and a bearing fitting section along the axial direction from the outside to the inside. The bearing fitting section is fitted with a bearing. b. Install the bearing mounted on the short shaft into the corresponding mounting groove on the first end cover of the housing of the rotary flow meter; then fasten the second end cover to the housing with screws so that the adjusting nut connecting section of the long shaft and the bearing mounting section extend out of the second end cover; an adjusting nut is fitted on the adjusting nut connecting section of the long shaft. Step 2: Assemble the synchronizing gears: Meshing synchronous gears are fitted into the synchronous pulley mounting sections of the long shafts of the two lap pulleys; The assembly contact surface between the outer side of the synchronous pulley mounting section of the long shaft and the inner side of the synchronous gear is a tapered surface. The second step, assembling the synchronizing gears, also includes the following steps: a. Gap detection: Select a feeler gauge with the corresponding thickness according to the maximum thickness of the design. Use the feeler gauge to insert into the gap between the lap rollers and between the lap rollers and the outer shell. If the feeler gauge can pass through, the gap meets the design requirements. When the feeler gauge cannot pass through the gap between a pair of rotary wheels, proceed with step b below; b. Adjustment of the distance between the waist rollers: When the feeler gauge cannot pass through the gap between a pair of rollers, one of the rollers is regarded as the reference roller and the other as the adjustment roller. Manually rotate the reference waist wheel by 90 degrees until it is in the same rotational angle as the reference waist wheel and in contact with the reference waist wheel. A strip-shaped blocking block is inserted into the machine housing through the inlet or outlet and is positioned between the reference cam and the machine housing to block the reference cam. Use a special wrench to turn the locking nut at the outermost end of the long shaft corresponding to the waist wheel clockwise. This increases the distance between the two waist wheels by using the taper of the tapered surface that mates with the synchronous gear, until a feeler gauge can pass through.

2. The assembly method of the rotary flow meter according to claim 1, characterized in that: In step a of "Step 1, assembling the waist wheel": A threaded hole is provided on the axial outer end face of the short shaft. An adjusting screw with an elastic washer is used. The outer edge of the elastic washer abuts against the axial outer end face of the bearing. The outer thread surface of the adjusting screw is coated with thread adhesive and screwed into the threaded hole. After the adjusting screw head is pressed against the elastic washer, continue to rotate it 270 degrees in the tightening direction.

3. The assembly method of the rotary flow meter according to claim 1, characterized in that: The rotary flow meter has an inlet structure, which includes a guide surface provided at the orifice of the inlet of the rotary flow meter. The guide surface enables the flowing medium to converge and be directed toward the junction between a pair of rotary impellers in the rotary flow meter.

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