Roots flowmeter assembling method

Abstract

The invention discloses a method for assembling a waist wheel flowmeter, which is characterized by comprising the following steps of: 1, assembling waist wheels: coaxially and fixedly connecting one end of a central shaft hole of each waist wheel with one end of a short shaft, and sleeving a bearing at the other end of the short shaft; the other end of the central shaft hole of each waist wheel is coaxially and fixedly connected with one end of a long shaft and then assembled and connected with a bearing, the other section of the long shaft is provided with a locking nut connecting section, a synchronizing wheel mounting section, an adjusting nut connecting section and a bearing sleeving section from outside to inside in the axial direction, and the bearing sleeving section is sleeved with the bearing; a bearing sleeved on the short shaft is arranged in a corresponding mounting groove on a first end cover of a casing of the roots flowmeter; the second end cover is fixedly connected to the machine shell through a screw, and the adjusting nut connecting section and the bearing sleeving section of the long shaft extend out of the second end cover; the adjusting nut connecting section of the long shaft is sleeved with an adjusting nut; and secondly, synchronous gears are assembled, wherein the synchronous gear mounting sections of the long shafts of the two waist wheels are sleeved with the meshed synchronous gears.

Description

[0001] This application is a divisional application of application number 202210838128X, application date 2022.07.17, and name “Inlet structure, rotary flowmeter and assembly method thereof”. Technical Field

[0002] The invention belongs to the field of rotary flowmeters, and in particular relates to an assembly method of a rotary flowmeter. Background Art

[0003] The rotary flowmeter is a rotor-type volumetric flowmeter, also known as a Roots flowmeter. There is a metering chamber in the housing of the flowmeter, and a pair of rotary wheels that can rotate tangentially. The rotary flowmeter is a metering instrument used to continuously or intermittently measure the flow of the medium (gas or liquid) in the pipeline. It has the characteristics of high accuracy, good reliability, light weight, long life, and easy installation and use.

[0004] The patent document with announcement number CN113188625A in the prior art discloses a rotary flow meter, which includes a casing, two sides of which are symmetrically provided with flow guide ports, one end of the casing is fixedly provided with a bottom cover, the other end of the casing is fixedly provided with a top cover, a flow indicator is fixedly provided on the outer side of the top cover, a metering chamber is provided inside the casing, two rotating shafts are movably provided inside the metering chamber, and the two ends of the rotating shafts extend into the bottom cover and the top cover respectively, a rotary wheel is fixedly provided on the outer ring of the rotating shaft, a transmission chamber is provided inside the top cover, a pair of meshing synchronous gear rings are movably provided inside the transmission chamber, a mounting sleeve shaft is movably provided inside the transmission chamber at the center of the synchronous gear ring, and the top cover is provided inside the synchronous gear ring. A magnetic coupler is movably installed between the gear ring and the flow display, a limit pin is movably installed at the end face of the rotating shaft inside the bottom cover, a clamping block is fixedly clamped on the outer side of the limit pin, a spiral end cover is threadedly sleeved on the outer side of the clamping block, a transmission gear column is movably installed between the inner ring of the synchronous gear ring and the outer ring of the mounting sleeve shaft on the side of the transmission cavity close to the magnetic coupler, a driven block is evenly fixedly installed on the inner ring of the synchronous gear ring in an annular shape, one side of the driven block is fixedly connected to the sleeve block, the outer ring of the mounting sleeve shaft is evenly fixedly installed with rotating blocks in an annular shape, the number of rotating blocks and driven blocks is the same and they are distributed alternately, a movable groove movably sleeved with the sleeve block is provided inside the rotating block, and a clamping groove movably sleeved with the rotating shaft is provided on the side of the mounting sleeve shaft close to the casing.

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

[0006] After the measured medium enters through the inlet on the housing, it will diffuse around in the metering cavity of the housing, which will reduce the rotation response of the waist wheel and affect the metering accuracy of the medium. At the same time, it cannot block impurities.

[0007] Based on this, the applicant considered designing a method for assembling a rotary flow meter that can improve the metering accuracy. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a method for assembling a rotary flowmeter that can improve the metering accuracy.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

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

[0011] The first step is to assemble the waist wheel:

[0012] a. One end of the central shaft hole of each waist wheel is coaxially fixedly connected with 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 with one end of the long shaft and then assembled with the bearing, and the other section of the long shaft is a synchronous wheel installation section, an adjusting nut connection section and a bearing fitting section from the outside to the inside along the axial direction, and the bearing fitting section is fitted with a bearing;

[0013] b. Install the bearing sleeved on the short shaft into the corresponding mounting groove on the first end cover of the housing of the impeller flowmeter; then fasten the second end cover to the housing by screws and make the adjusting nut connecting section and the bearing sleeve section of the long shaft extend to the outside of the second end cover; an adjusting nut is sleeved on the adjusting nut connecting section of the long shaft;

[0014] Step 2: Assemble the synchronous gear:

[0015] The synchronous gears meshing with each other are installed on the synchronous wheel installation sections of the long shafts of the two waist wheels;

[0016] Different from the existing rotary flowmeter which uses a straight-through pipe (cylindrical hole channel) as the air intake structure, the inlet structure of the present invention has the following advantages:

[0017] 1. The above-mentioned guide surface is set at the orifice of the inlet of the impeller flowmeter. The guide surface can make the medium flow passing through converge and shoot to the intersection between a pair of impellers in the impeller flowmeter. In this way, it can effectively prevent the inflowing medium flow (air flow or liquid flow) from diffusing around after entering the metering cavity, but converge and shoot to and pass through the middle position of a pair of impeller rotors, so that the impeller rotors can obtain the best driving torque and respond more instantly and quickly to the flow of the medium flow, helping to improve the metering accuracy of the impeller flowmeter.

[0018] 2. The setting of the above-mentioned guide surface can also constitute a blocking surface for impurities, which can more effectively prevent impurities from entering the cavity of the impeller flowmeter, better avoid problems such as impeller jamming, and help improve the reliability of long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the rotary flowmeter of the present invention (viewed from above)

[0020] Figure 2 This is a schematic diagram of the structure of the waist wheel flow meter of the present invention (looking up)

[0021] Figure 3 The schematic diagram of the structure of the housing of the rotary flow meter of the present invention is

[0022] Figure 4 for Figure 3 Middle II line cross-section view

[0023] Figure 5 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 A partial enlarged view of the dotted box

[0027] Fig. 9 The schematic diagram of the structure of the long axis of the rotary flow meter of the present invention is

[0028] Fig.10 Schematic diagram of the detection of the gap between the impellers in the impeller flowmeter assembly method of the present invention

[0029] Fig.11 Schematic diagram of adjusting the clearance of the impeller in the impeller flowmeter assembly method of the present invention

[0030] Fig.12 Schematic diagram of the detection of the gap between the impellers in the impeller flowmeter assembly method of the present invention

[0031] Fig.13 Schematic diagram of adjusting the clearance of the impeller in the impeller flowmeter assembly method of the present invention

[0032] The figure is marked as;

[0033] 10 Casing: 1011 temperature measuring hole, 1012 pressure taking hole

[0034] 11 Upper guide block

[0035] 12 Lower guide block

[0036] 13. Guide surface

[0037] 14 waist wheel

[0038] 15 short axis

[0039] 16 Long shaft: 161 locking nut connection section, 162 synchronous wheel installation section, 163 adjusting nut connection section, 164 bearing set section

[0040] 17 Elastic gasket

[0041] 18 Adjustment screw

[0042] 19 bearings

[0043] 20 Synchronous gear

[0044] 21 Lock nut

[0045] 22 Feeler Gauge

[0046] 23 Reference waist wheel

[0047] 24 Adjustable waist wheel

[0048] 25 bar blocks DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0050] When implementing: Figures 1 to 13 As shown,

[0051] The inlet structure includes a guide surface arranged at the orifice of the inlet of the impeller flowmeter, wherein the guide surface can make the medium flow passing through converge and project to the intersection between a pair of impellers in the impeller flowmeter.

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

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

[0054] The windward surfaces of the upper guide block and the lower guide block constitute the guide surface;

[0055] The lower end surface of the upper guide block is spaced apart from the upper end surface of the lower guide block and forms a convergent guide channel, which is used for converging the medium flow and projecting it toward the intersection between a pair of impellers in the impeller flowmeter.

[0056] The upper guide block and the lower guide block are integrally formed with the orifice, that is, integrally formed with the housing of the rotary flowmeter. This makes it easy to integrally form the housing and the upper guide block and the lower guide block through a casting process, reducing the difficulty of processing and setting the upper guide block and the lower guide block.

[0057] At the same time, since the upper guide block and the lower guide block are only arranged in the orifice of the inlet and the material consumption is relatively small, it is also easy to effectively control the cost and avoid increasing the product manufacturing cost due to improving the metering accuracy.

[0058] In addition, the structural setting of the upper guide block and the lower guide block can further improve the structural strength of the inlet and the casing of the rotary flow meter, and further improve the explosion-proof performance.

[0059] In summary, the use of the above-mentioned upper guide block and lower guide block can improve the metering accuracy at a lower cost, and has better economic benefits and use value.

[0060] The upper guide block and the lower guide block are mirror-symmetrical in the up and down directions of the rotary flowmeter; the distance between the lower end surface of the upper guide block and the upper end surface of the lower guide block accounts for 60% to 65% of the orifice diameter of the inlet.

[0061] In this way, it can not only effectively prevent impurities in the gas pipeline from entering the flow meter.

[0062] The upper and lower guide blocks with mirror-symmetrical upper and lower surfaces can jointly form the optimal convergence and diversion effect, better avoid jet collision to reduce the kinetic energy of the medium flow, and ensure the realization of higher metering accuracy.

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

[0064] Among them, the upper guide block and the lower guide block are each thin in the middle and gradually thicken towards the two ends in the axial direction of the waist wheel; and the windward surfaces of the upper guide block and the lower guide block are each arc-shaped, and the radius of the arc-shaped surface gradually decreases inward in the axial direction of the orifice of the inlet.

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

[0066] Wherein, the upper guide block and the lower guide block are both arranged at the innermost end of the orifice of the inlet.

[0067] In this way, the depth of the orifice can be fully utilized, the travel of impurities in the orifice can be extended, the kinetic energy of the impurities can be reduced, and the upper guide block and the lower guide block can be used to achieve the best impurity blocking effect.

[0068] At the same time, based on the fact that "the upper guide block and the lower guide block are both located at the innermost end of the inlet orifice", the distance to a pair of waist wheel rotors is the shortest, so it has the best convergence and diversion effect, achieving 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 arranged in mirror symmetry with the inlet structure.

[0071] By adopting the above-mentioned mirror-symmetrical outlet structure and inlet structure, the metering accuracy can be improved while the volume of the metering cavity can be increased without increasing the outer dimensions of the casing and the inner cavity volume of the rotary flowmeter.

[0072] The wheel flow meter structure using this technical solution can achieve two-way metering, namely left air inlet and right air outlet, right air inlet and left air outlet. The metering accuracy can reach 0.5 level, which is much higher than the 1.5 level metering accuracy of other ordinary flow meters.

[0073] Wherein, temperature measuring holes and pressure taking hole structures are arranged on the inlet and the outlet.

[0074] In this way, two-way air intake, two-way temperature measurement and pressure measurement can be achieved.

[0075] The temperature measuring hole and pressure taking hole structure can be installed by plugging or using corresponding sensors, and has strong versatility.

[0076] The axis of the pressure hole structure should be perpendicular to the axis of the measuring tube, with a diameter of (3-12) mm, and the minimum length of the pressure hole should be equal to the hole diameter. The influence of the measurement error of the pressure gauge used on the calibration result should be within 5% of the maximum allowable error of the flow meter.

[0077] The temperature measuring hole structure can be used to place the temperature sensor in the middle of the inlet flange diameter. The temperature taken is the central temperature of the fluid, ensuring the accuracy of temperature collection.

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

[0079] The first step is to assemble the waist wheel:

[0080] a. One end of the central shaft hole of each waist wheel is coaxially fixedly connected with 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 with one end of the long shaft and then assembled with the bearing, and the other section of the long shaft is a synchronous wheel installation section, an adjusting nut connection section and a bearing fitting section from the outside to the inside along the axial direction, and the bearing fitting section is fitted with a bearing;

[0081] b. Install the bearing sleeved on the short shaft into the corresponding mounting groove on the first end cover of the housing of the impeller flowmeter; then fasten the second end cover to the housing by screws and make the adjusting nut connecting section and the bearing sleeve section of the long shaft extend to the outside of the second end cover; an adjusting nut is sleeved on the adjusting nut connecting section of the long shaft;

[0082] Step 2: Assemble the synchronous gear:

[0083] The synchronous wheel installation sections of the long shafts of the two waist wheels are sleeved with synchronous gears which mesh with each other.

[0084] During implementation, two pairs of disc springs are mounted on the long shaft between the bearing mounted on the long shaft and the adjacent waist wheel rotor. The cooperation between the two pairs of disc springs and the adjusting nut can adjust the reasonable gap between the bearing on the long shaft side and the end face of the waist wheel to prevent the bearing from getting stuck, thereby ensuring the reliability of rotation measurement.

[0085] The torque operation of adjusting the nut is:

[0086] Use a waterproof marker pen to mark the upper position of the waist wheel on the adjusting nut and the long shaft;

[0087] Rotate the adjusting nut until the waist wheel just touches the inner side of the inner end cover; mark the lower position of the waist wheel on the long axis;

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

[0089] Rotate the nut to the middle position, and then there will be a reasonable gap between the waist wheel and the back cover and the inner end cover, so that the waist wheel can move up and down.

[0090] In step a of "Step 1, Assemble the Waist Wheel":

[0091] A threaded hole is provided on the axial outer end face of the short shaft, and an adjusting screw with an elastic gasket is used, the outer edge of the elastic gasket abuts against the axial outer end face of the bearing, and the outer thread surface of the adjusting screw is coated with thread glue and screwed into the threaded hole through threads;

[0092] Twist the adjusting screw until the screw head is crimped onto the elastic gasket and continue to rotate it about 270 degrees in the tightening direction.

[0093] By means of the threaded hole, elastic gasket and adjusting screw at the end of the rear axle, as well as the twisting assembly method of the adjusting screw, a certain gap can be maintained between the waist wheel, the rear axle and the bearing to avoid the waist wheel and the bearing from being pressed tightly, preventing the bearing from being stuck, and ensuring that the bearing can rotate normally for a long time.

[0094] At the same time, a small amount of thread glue is applied to the outer thread surface of the adjusting screw before assembly to prevent the adjusting screw from loosening when the bearing runs at high speed, thereby better ensuring the long-term reliability of the adjusting screw in regulating the above-mentioned clearance.

[0095] During implementation, before the bearing of the short shaft is assembled into the mounting groove, grease is applied to the inner and outer rings of the short shaft and the bearing. This can effectively reduce friction, reduce the rapid temperature rise caused by high-speed operation of the bearing, and improve reliability.

[0096] The assembly contact surface between the outer side surface of the synchronous wheel mounting section of the long shaft and the inner side surface of the synchronous gear is a conical surface;

[0097] The "Second Step, Assembling Synchronous Gears" also includes the following steps:

[0098] a. Gap detection:

[0099] Choose a feeler gauge of corresponding thickness according to the designed maximum thickness, and use the feeler gauge to insert it into the gap between the waist wheels and between the waist wheels and the shell. When 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 waist wheels, use the following step b;

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

[0102] When the feeler gauge cannot pass through the gap between a pair of waist wheels, one of the two waist wheels is regarded as a reference waist wheel and the other as an adjustment waist wheel;

[0103] Manually adjust the reference waist wheel to rotate 90 degrees, and adjust the waist wheel to rotate to the same angle as the reference waist wheel and contact the reference waist wheel;

[0104] A bar-shaped blocking block is inserted into the housing through the inlet or outlet and is stuck between the reference waist wheel and the housing to form a blocking for the reference waist wheel;

[0105] Use a wrench to twist the locking nut at the outermost end of the long shaft corresponding to the waist wheel clockwise, that is, use the taper of the conical surface between the long shaft and the synchronous gear to increase the distance between the two waist wheels until a feeler gauge can pass through.

[0106] The above-mentioned "the assembly contact surface between the outer side surface of the synchronous wheel mounting section of the long shaft and the inner side surface of the synchronous gear is a conical surface", so 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 by clamping the thickness of the feeler gauge between the two waist wheels, and at the same time, check the gap between the waist wheels and the waist wheels and the housing with the feeler gauge, and use the feeler gauge to check whether the gap meets the requirements. Assemble the synchronous gear, block the waist wheel with a plastic block (strip blocking block), then put the feeler gauge on the other side, press down the waist wheel by hand in the direction of the gap, and fix it with appropriate torque.

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

[0109] like Fig. 9 If the position gap is small, turn 90° to Fig.10 Position and clamp the waist wheel, and tighten it with appropriate torque;

[0110] like Fig.11 If the position gap is small, turn 90° to Fig.12 Position and lock the waist wheel, and tighten it with appropriate torque.

[0111] The above are only preferred implementations of the present invention. It should be pointed out that a number of modifications and improved technical solutions made by those skilled in the art without departing from the technical solution should also be deemed to fall within the scope of protection required by the claims.

Claims

1. Assembly method of the rotary flow meter, characterized in that: The following steps are involved: The first step is to assemble the waist wheel: a. One end of the central shaft hole of each waist wheel is coaxially fixedly connected with 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 with one end of the long shaft and then assembled with the bearing, and the other section of the long shaft is axially from outside to inside, including a locking nut connecting section, a synchronous wheel installation section, an adjusting nut connecting section and a bearing fitting section, and the bearing fitting section is fitted with a bearing; b. Install the bearing sleeved on the short shaft into the corresponding mounting groove on the first end cover of the housing of the impeller flowmeter; then fasten the second end cover to the housing by screws and make the adjusting nut connecting section and the bearing sleeve section of the long shaft extend to the outside of the second end cover; an adjusting nut is sleeved on the adjusting nut connecting section of the long shaft; Step 2: Assemble the synchronous gear: The synchronous wheel installation sections of the long shafts of the two waist wheels are sleeved with synchronous gears which mesh with each other.

2. The assembly method of the rotary flowmeter according to claim 1, characterized in that: In step a of "Step 1, Assemble the Waist Wheel": A threaded hole is provided on the axial outer end face of the short shaft, and an adjusting screw with an elastic gasket is used, the outer edge of the elastic gasket abuts against the axial outer end face of the bearing, and the outer thread surface of the adjusting screw is coated with thread glue and screwed into the threaded hole through threads; Twist the adjusting screw until the screw head is crimped onto the elastic gasket and continue to rotate it about 270 degrees in the tightening direction.

3. The assembly method of the rotary flowmeter according to claim 1, characterized in that: The assembly contact surface between the outer side surface of the synchronous wheel mounting section of the long shaft and the inner side surface of the synchronous gear is a conical surface; The "Second Step, Assembling Synchronous Gears" also includes the following steps: a. Gap detection: Choose a feeler gauge of corresponding thickness according to the designed maximum thickness, and use the feeler gauge to insert it into the gap between the waist wheels and between the waist wheels and the shell. When 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 waist wheels, use the following step b; b. Adjustment of the distance between the waist wheels: When the feeler gauge cannot pass through the gap between a pair of waist wheels, one of the two waist wheels is regarded as a reference waist wheel and the other as an adjustment waist wheel; Manually adjust the reference waist wheel to rotate 90 degrees, and adjust the waist wheel to rotate to the same angle as the reference waist wheel and contact the reference waist wheel; A bar-shaped blocking block is inserted into the housing through the inlet or outlet and is stuck between the reference waist wheel and the housing to form a blocking for the reference waist wheel; Use a special wrench to twist the locking nut at the outermost end of the long shaft corresponding to the waist wheel clockwise, that is, use the taper of the conical surface between the long shaft and the synchronous gear to increase the distance between the two waist wheels until the feeler gauge can pass through.

4. The assembly method of the rotary flowmeter according to claim 1, characterized in that: The impeller flowmeter has an inlet structure, which includes a guide surface arranged at the orifice of the inlet of the impeller flowmeter, and the guide surface can make the medium flow passing through converge and shoot toward the intersection between a pair of impellers in the impeller flowmeter.

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