Double-screw flowmeter

Abstract

The utility model discloses a double-screw flowmeter, which relates to the technical field of measuring instruments and comprises a measuring chamber and two screws, and the two screws are arranged in the measuring chamber and meshed with each other. The two screw rods are respectively a driving screw rod and a driven screw rod, the correspondingly arranged end parts of the two screw rods are respectively provided with a thrust bearing assembly, and the end part of the driving screw rod, which is not provided with the thrust bearing assembly, is connected with a flow instrument; the thrust bearing assembly comprises a mixed ceramic ball bearing arranged on the outer peripheral face of the end of the screw; the alloy rotating piece is arranged on the end face of the screw rod and is used for synchronously rotating with the screw rod; the alloy static part is located on the outer side of the end face of the screw and provided with a working face facing the alloy rotating part, the working face is rotatably connected with the end face, facing the alloy static part, of the alloy rotating part, and the surface area of the working face is smaller than that of the end face, facing the alloy static part, of the alloy rotating part. According to the double-screw flowmeter, the service life is prolonged, the durability is improved, and the use precision is improved.

Description

Technical Field

[0001] The present application relates to the technical field of measuring instruments, and in particular to a twin-screw flowmeter. Background Art

[0002] A positive displacement flow meter is an instrument that accumulates flow directly based on the volume of the discharged fluid. That is, the total volume of the measured fluid is obtained by multiplying the standard volume of the metering chamber by the standard volume of the fluid discharged through the flow meter within a certain time interval.

[0003] In the related art, a twin-screw flowmeter includes a metering chamber, inside which an active screw rotor and a driven screw rotor are arranged. Four-corner point contact bearings are used at both ends of the active screw rotor and the driven screw rotor. The material is usually carbon steel to withstand radial force and axial force. Since the twin-screw flowmeter is used in an environment with heavy oil and vapor and has poor lubricity, the contact bearing has a short life and poor durability, which in turn affects the accuracy of use. Utility Model Content

[0004] The utility model aims to provide a twin-screw flowmeter, which increases service life, increases durability and improves use accuracy.

[0005] To achieve the above object, the utility model provides a twin-screw flowmeter, including a metering chamber, and the twin-screw flowmeter also includes:

[0006] Two screws are arranged in the metering chamber and mesh with each other; the two screws are respectively a driving screw and a driven screw, and thrust bearing assemblies are arranged at the corresponding ends of the two screws, and the end of the driving screw without the thrust bearing assembly is connected to the flow meter;

[0007] The thrust bearing assembly consists of:

[0008] A hybrid ceramic ball bearing is provided on the outer peripheral surface of the end of the screw;

[0009] The alloy rotating part is arranged on the end surface of the screw and is used to rotate synchronously with the screw;

[0010] The alloy stationary part is located outside the end face of the screw and has a working surface arranged facing the alloy rotating part. The working surface is rotatably connected to the end face of the alloy rotating part facing the alloy stationary part, and the surface area of ​​the working surface is smaller than the surface area of ​​the end face of the alloy rotating part facing the alloy stationary part.

[0011] Preferably, a limiting groove is provided on the end face of the screw, the depth direction of the limiting groove is the axial direction of the screw, and the alloy rotating part is fixed in the limiting groove.

[0012] Preferably, the alloy stationary part further comprises an inclined edge arranged around the working surface, and the inclined edge extends obliquely toward the radial inner side of the alloy stationary part in a direction facing the alloy rotating part to reduce the surface area of ​​the working surface.

[0013] Preferably, the inclined edge is one of a chamfer, a rounded slope and a curved surface.

[0014] Preferably, the twin-screw flowmeter further comprises a bearing adjustment seat, the bearing adjustment seat is located on a side of the hybrid ceramic ball bearing away from the screw, and the alloy stationary part is embedded in the interior of the bearing adjustment seat.

[0015] Preferably, the twin-screw flowmeter also includes a bearing seat, a hybrid ceramic ball bearing is installed in the bearing seat, the bearing seat is provided with a through hole, the end of the bearing adjustment seat facing the screw can move in the through hole, the outer periphery of the bearing adjustment seat is provided with an external thread, the locking nut is located outside the end face of the through hole, the internal thread and external thread of the locking nut match, and the end face of the locking nut facing the screw and the end face of the through hole are abutted.

[0016] Preferably, the bearing seat comprises:

[0017] The seat body is provided with a bearing mounting hole, the inner wall of the bearing mounting hole is fixed to the outer ring of the hybrid ceramic ball bearing, and the through hole is arranged on the end face of the bearing mounting hole away from the screw.

[0018] Preferably, the twin-screw flowmeter also includes a connecting flange, which is connected to the bearing seat and forms a receiving cavity. The portion of the bearing adjustment seat located outside the through hole and the locking nut are both located in the receiving cavity, and in the axial direction of the connecting flange, the bearing adjustment seat and the connecting flange are spaced apart.

[0019] Preferably, the hybrid ceramic ball bearing connected to the active screw and the hybrid ceramic ball bearing connected to the driven screw are spaced apart in an axial direction perpendicular to the active screw.

[0020] Preferably, a code disk is provided on the end of the active screw connected to the flow meter, the flow meter is mounted on the metering chamber, and the flow meter and the code disk are connected via a sensor to convert the rotation angle signal of the active screw rotor into a pulse signal.

[0021] Compared with the above-mentioned background technology, the twin-screw flowmeter provided by the utility model is provided with thrust bearing assemblies at the corresponding ends of the two screws. The thrust bearing assembly includes a hybrid ceramic ball bearing, an alloy rotating part and an alloy stationary part. The hybrid ceramic ball bearing is arranged on the outer peripheral surface of the end of the screw. Considering the material of the hybrid ceramic ball bearing, it can certainly improve the service life. However, since the application has high requirements on the operation accuracy of the screw, only the method of arranging the hybrid ceramic ball bearing on the outer peripheral surface of the end of the screw cannot meet the corresponding requirements. Based on this, the applicant further adopts the method of matching the alloy rotating part and the alloy stationary part, that is, the alloy rotating part is arranged on the end face of the screw, and is rotatably connected to the alloy rotating part through the working surface of the alloy stationary part, and at the same time, the surface area of ​​the working surface is smaller than the surface area of ​​the alloy rotating part facing the alloy The surface area of ​​the end face of the stationary part can be considered that the alloy rotating part and the alloy stationary part constitute a thrust bearing as a whole. The alloy stationary part can be regarded as the stationary part of the thrust bearing, and the alloy rotating part can be regarded as the rotating part of the thrust bearing. The contact area of ​​the contact part (rotatable connection part) between the alloy rotating part and the alloy stationary part is small to ensure that they can withstand a large axial force and at the same time make the friction between the two smaller. In addition, the alloy material of the alloy rotating part and the alloy stationary part can improve the service life. It can be seen that the present application utilizes a hybrid ceramic ball bearing and a thrust bearing (the thrust bearing includes an alloy rotating part and an alloy stationary part) arranged in a special way. After being used in combination, it can significantly improve durability, increase service life, and improve the accuracy of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 A cross-sectional view of a twin-screw flowmeter provided in an embodiment of the present application;

[0024] Figure 2 A partial enlarged view of a thrust bearing assembly of a twin-screw flowmeter provided in an embodiment of the present application;

[0025] in:

[0026] 1-flange, 2-bearing seat, 3-flow meter, 4-sensor, 5-code disc, 6-metering chamber, 7-driving screw, 8-driven screw, 9-bearing seat, 10-connecting flange, 11-hybrid ceramic ball bearing, 12-alloy rotating part, 13-alloy stationary part, 14-bearing adjustment seat, 15-locking nut, 16-bearing mounting hole;

[0027] 01-working surface, 02-limiting groove, 03-inclined edge, 04-through hole, 05-external thread. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] Please see attached Figure 1 A twin-screw flowmeter provided in an embodiment of the present application includes a metering chamber 6, inside which are provided two screws meshing with each other, the two screws being a driving screw 7 and a driven screw 8. When in use, when the fluid enters the metering chamber 6, it will push the driving screw 7 to rotate, and the rotating driving screw 7 drives the driven screw 8 to rotate synchronously through meshing transmission.

[0031] The first end of the active screw 7 ( Figure 1 The left end in the figure is connected to a flow meter 3, which is used to detect the liquid flow in the pipeline.

[0032] In some embodiments, the first end of the active screw 7 ( Figure 1 The left end of the flow meter 3 is provided with a code disk 5, the flow meter 3 can be installed on the metering chamber 6, most of the structure of the flow meter 3 is located outside the metering chamber 6, and the sensor 4 is installed inside the metering chamber 6. The flow meter 3 and the code disk 5 are electrically connected through the sensor 4, so that the rotation angle signal of the active screw 7 is converted into a pulse signal.

[0033] When in use, the active screw 7 and the code disc 5 rotate synchronously, and the code disc 5 can reflect the number of rotations of the active screw 7. Since the flow meter 3, the sensor 4 and the code disc 5 are connected, the flow meter 3 can obtain the flow rate of the fluid through the number of rotations of the code disc 5, thereby completing the measurement of the flow rate. The flow meter 3 has functions such as signal conversion, reception, integration and display, and its specific setting method can refer to the existing technology, which will not be expanded in this article.

[0034] The second end of the active screw 7 ( Figure 1 The right end of the driven screw 8 and the second end of the driven screw 8 ( Figure 1The right end of the active screw 7 is provided with a thrust bearing assembly. The following only describes the thrust bearing assembly provided at the second end of the active screw 7 ( Figure 1 The thrust bearing assembly is described as an example, and is arranged at the second end of the driven screw 8 ( Figure 1 The thrust bearing assembly of the 2000-01-08 (right end in FIG. 1 ) is arranged in a similar manner.

[0035] The thrust bearing assembly includes a hybrid ceramic ball bearing 11, an alloy rotating member 12 and an alloy stationary member 13; the hybrid ceramic ball bearing 11 is arranged at the second end of the active screw 7 ( Figure 1 On the outer circumference of the right end of the hybrid ceramic ball bearing 11, namely the inner ring of the hybrid ceramic ball bearing 11 and the second end of the active screw 7 ( Figure 1 The outer circumferential surface of the right end in the middle is fixedly connected, which may be an interference fit, etc. The outer ring of the hybrid ceramic ball bearing 11 can be fixed at a corresponding position according to the actual scenario, thereby ensuring the rotation of the second end of the active screw 7.

[0036] The hybrid ceramic ball bearing 11 in this article includes inner and outer rings, rolling balls and retaining frames. The rolling balls and retaining frames are located between the inner ring and the outer ring. The inner ring and the outer ring are made of stainless steel, and the rolling balls are made of ceramic material. The ceramic material is a highly wear-resistant material, so it is called a hybrid ceramic ball bearing in the industry.

[0037] Herein, the hybrid ceramic ball bearing 11 used at the second end of the active screw 7 is of model QJ306, and the hybrid ceramic ball bearing 11 used at the second end of the driven screw is of model QJ303.

[0038] The hybrid ceramic ball bearing 11 connected to the active screw 7 and the hybrid ceramic ball bearing 11 connected to the driven screw 8 are spaced apart in an axial direction perpendicular to the active screw. The hybrid ceramic ball bearings 11 of different screws complement each other and will not cause excessive interference during assembly or rotation, thereby reducing mutual interference.

[0039] Combined with Figure 2 The alloy rotating part 12 is arranged on the second end face of the active screw 7, the alloy rotating part 12 and the active screw 7 rotate synchronously, the alloy stationary part 13 is located outside the second end face of the active screw 7, and the alloy stationary part 13 has a working surface 01 facing the alloy rotating part 12, that is, the working surface 01 is located at the left end of the alloy stationary part 13.

[0040] The working surface 01 is rotatably connected to the end surface of the alloy rotating part 12 facing the alloy stationary part 13, that is, the right end surface of the alloy rotating part 12 and the left end surface of the alloy stationary part 13 are rotatably connected. Obviously, the alloy rotating part 12 and the alloy stationary part 13 are coaxially arranged, and the centroid of the working surface 01 is located on the axis of the alloy rotating part 12 and the alloy stationary part 13.

[0041] The surface area of ​​the working surface 01 is smaller than the surface area of ​​the end surface of the alloy rotating part 12 facing the alloy stationary part 13. Figure 2 , the surface area of ​​the working surface 01 is smaller than the right end surface of the alloy rotating part 12. The cross-sectional area of ​​the alloy stationary part 13 is not smaller than the cross-sectional area of ​​the alloy rotating part 12, and the working surface 01 can be regarded as an end surface formed by a chamfering process to reduce the contact area between the alloy stationary part 13 and the alloy rotating part 12 (the surface area of ​​the working surface 01).

[0042] It can be considered that the alloy rotating part 12 and the alloy stationary part 13 constitute a thrust bearing for bearing a certain axial force. The contact area between the alloy rotating part 12 and the alloy stationary part 13 is small, so the friction is small. When used in conjunction with the hybrid ceramic ball bearing 11, the rotation accuracy of the active screw 7 at the second end face can be significantly improved, and the durability is good and the use is reliable. The alloy rotating part 12 and the alloy stationary part 13 can be made of cemented carbide of various specifications, and the hardness is generally high. The material grade in this application is YG6, which belongs to tungsten-cobalt cemented carbide.

[0043] As described above, for the second end of the driven screw 8 ( Figure 1 The thrust bearing assembly is arranged in a manner such that the second end of the active screw 7 ( Figure 1 The thrust bearing assembly of the embodiment of the present invention is arranged in a similar manner and will not be expanded here.

[0044] In addition, for the first end of the active screw 7 ( Figure 1 The left end of the driven screw 8 and the first end of the driven screw 8 ( Figure 1 The setting method of the left end in the figure) can adopt the setting method of the hybrid ceramic ball shaft 11 as described above, and there is no need to set the alloy rotating part 12 and the alloy stationary part 13.

[0045] As attached Figure 1 The left end of the twin-screw flowmeter is a flange 1, which is connected to a bearing seat body 2. The bearing seat body 2 is located at the left end of the metering chamber 6. The bearing seat body 2 is located between the flange 1 and the metering chamber 6. The bearing seat body 2 can be regarded as a local structure of the metering chamber 6. The flow meter 3 is specifically installed on the bearing seat body 2. The bearing seat body 2 is also equipped with a first end of the active screw 7 ( Figure 1 The left end of the driven screw 8 ( Figure 1 The bearing of the left end in the figure can also be a hybrid ceramic ball shaft 11, which will not be expanded here.

[0046] Combined with Figure 2 , the second end of the screw ( Figure 1 The end face of the rotatable member 12 is provided with a limiting groove 02, the depth direction of the limiting groove 02 is the axial direction of the screw, the alloy rotating member 12 is fixed in the limiting groove 02, and the screws are the active screw 7 and the driven screw 8.

[0047] It can be seen that in order to ensure the fixed connection between the alloy rotating part 12 and the screw, the present application directly opens a limit groove 02 at the second end of the screw, and the alloy rotating part 12 can be fixed in the limit groove 02 by interference fit to ensure a reliable connection between the alloy rotating part 12 and the screw.

[0048] Continue to refer to the attached Figure 2 The alloy stationary part 13 further includes an inclined edge 03 arranged around the working surface 01, and the inclined edge 03 extends obliquely toward the radial inner side of the alloy stationary part 13 in the direction facing the alloy rotating part 12 to reduce the surface area of ​​the working surface 01. In short, the working surface 01 of the alloy stationary part 13 is a boss structure, so that the contact area between the working surface 01 and the alloy rotating part 12 is small, so as to achieve the purpose of small friction torque and being able to withstand axial force.

[0049] The inclined edge 03 may specifically be one of a chamfer, a rounded slope and a cambered surface. For example, the inclined edge 03 is formed by turning the left end surface of the alloy stationary part 13 with a corresponding tool.

[0050] See attached Figure 1 and attached Figure 2 The twin-screw flowmeter is also provided with a bearing adjustment seat 14 , which is located on the side of the hybrid ceramic ball bearing 11 away from the screw, and the alloy stationary part 13 is embedded in the bearing adjustment seat 14 .

[0051] It can be seen that the alloy stationary part 13 is fixed inside the bearing adjustment seat 14. Considering that the alloy stationary part 13 is a highly wear-resistant material, difficult to process, and expensive, it is made into a small structure and embedded in the bearing adjustment seat 14. The bearing adjustment seat 14 is a common material that is easy to process, which can effectively reduce the manufacturing cost. The installation process of the alloy stationary part 13 and the bearing adjustment seat 14 is relatively simple and reliable. On the premise of ensuring the above-mentioned technical effects, the production difficulty can be reduced.

[0052] Looking further, the twin-screw flowmeter also includes a bearing seat 9, a hybrid ceramic ball bearing 11 is installed in the bearing seat 9, the bearing seat 9 is provided with a through hole 04, the end of the bearing adjustment seat 14 facing the screw can move in the through hole 04, the outer periphery of the bearing adjustment seat 14 is provided with an external thread 05, the locking nut 15 is located outside the end face of the through hole 04, the internal thread of the locking nut 15 and the external thread 05 cooperate, and the end face of the locking nut 15 facing the screw and the end face of the through hole 04 are abutted.

[0053] Taking into account that the screws (active screw 7 and driven screw 8) of the twin-screw flowmeter are long axes, their installation positions in the flowmeter are restricted by other structures, and there are requirements for the axial flow of the screws. If the flow is large, the limit of the relevant bearings will not meet the requirements. If the flow is small, it will expand at a higher temperature and there may be a risk of jamming. Therefore, during assembly, the axial clearance needs to be adjusted to a reasonable range, which needs to be considered comprehensively based on the use environment and the length of the flowmeter. The axial clearance can be adjusted by the bearing adjustment seat 14.

[0054] The axial position of the bearing adjustment seat 14 in the through hole 04 is adjustable, that is, the axial position of the alloy stationary part 13 is adjusted by the bearing adjustment seat 14, and then the axial position of the alloy rotating part 12 and the screw is adjusted. After the axial position of the bearing adjustment seat 14 is adjusted, the locking nut 15 is used to lock it. The end face of the locking nut 15 facing the screw and the end face of the through hole 04 are abutted against each other. In this way, the locking nut 15 can be used to fix the axial position of the bearing adjustment seat 14 to prevent the screw from loosening during operation.

[0055] In some embodiments, the bearing seat 9 includes a seat body, which is provided with a bearing mounting hole 16, the inner wall of the bearing mounting hole 16 is fixed to the outer ring of the hybrid ceramic ball bearing 11, and the through hole 04 is provided on the end face of the bearing mounting hole 16 away from the screw.

[0056] Reference Figure 1 It can be seen that the main purpose of the bearing mounting hole 16 is to place the hybrid ceramic ball bearing 11. The outer ring of the hybrid ceramic ball bearing 11 is fixed on the inner wall of the bearing mounting hole 16, and the end face of the bearing mounting hole 16 away from the screw is located at the adjacent Figure 1 The right end of the bearing is provided with a through hole 04 for the bearing adjustment seat 14 to extend into the through hole 04 to adjust the axial position. In addition, the end surface of the bearing mounting hole 16 facing away from the screw rod abuts against the locking nut 15 to fix the bearing adjustment seat 14.

[0057] See the attached Figure 1 The twin-screw flowmeter also includes a connecting flange 10. The connecting flange 10 and the bearing seat 9 are connected to each other to form an accommodating cavity. The portion of the bearing adjustment seat 14 located outside the through hole 04 and the locking nut 15 are both located in the accommodating cavity, and in the axial direction of the connecting flange 10, the bearing adjustment seat 14 and the connecting flange 10 are spaced apart.

[0058] The bearing seat 9 and the connecting flange 10 are used to form a receiving cavity, and the bearing adjustment seat 14 has a certain axial adjustment space in the receiving cavity, which not only facilitates assembly and disassembly and simplifies the operation and maintenance process, but also can reduce spatial interference and improve reliability.

[0059] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0060] This article uses specific examples to illustrate the principles and implementation methods of the utility model. The above examples are only used to help understand the method and core ideas of the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the utility model.

Claims

1. A twin-screw flowmeter, comprising a metering chamber, characterized in that: The twin-screw flow meter also includes: Two screws are arranged in the metering chamber and mesh with each other; the two screws are respectively a driving screw and a driven screw, and the corresponding ends of the two screws are provided with thrust bearing assemblies, and the end of the driving screw not provided with the thrust bearing assembly is connected to the flow meter; The thrust bearing assembly comprises: A hybrid ceramic ball bearing is arranged on the outer peripheral surface of the end of the screw; An alloy rotating member, disposed on the end surface of the screw, and configured to rotate synchronously with the screw; The alloy stationary part is located outside the end face of the screw and has a working surface arranged facing the alloy rotating part. The working surface is rotatably connected to the end face of the alloy rotating part facing the alloy stationary part, and the surface area of ​​the working surface is smaller than the surface area of ​​the end face of the alloy rotating part facing the alloy stationary part.

2. The twin-screw flowmeter according to claim 1, characterized in that: The end surface of the screw is provided with a limiting groove, the depth direction of the limiting groove is the axial direction of the screw, and the alloy rotating part is fixed in the limiting groove.

3. The twin-screw flowmeter according to claim 1, characterized in that: The alloy stationary part further comprises an inclined edge arranged around the working surface, wherein the inclined edge extends obliquely toward the radial inner side of the alloy stationary part in a direction facing the alloy rotating part to reduce the surface area of ​​the working surface.

4. The twin-screw flowmeter according to claim 3, characterized in that: The inclined edge is specifically one of a chamfer, a rounded slope and a curved surface.

5. The twin-screw flowmeter according to any one of claims 1 to 4, characterized in that: The twin-screw flowmeter further comprises a bearing adjustment seat, which is located on a side of the hybrid ceramic ball bearing away from the screw, and the alloy stationary part is embedded in the bearing adjustment seat.

6. The twin-screw flowmeter according to claim 5, characterized in that: The twin-screw flowmeter also includes a bearing seat, the hybrid ceramic ball bearing is installed in the bearing seat, the bearing seat is provided with a through hole, the end of the bearing adjustment seat facing the screw can move in the through hole, the outer periphery of the bearing adjustment seat is provided with an external thread, the locking nut is located outside the end face of the through hole, the internal thread of the locking nut and the external thread cooperate, and the end face of the locking nut facing the screw and the end face of the through hole are abutted.

7. The twin-screw flowmeter according to claim 6, characterized in that: The bearing seat comprises: The seat body is provided with a bearing mounting hole, the inner wall of the bearing mounting hole is fixed to the outer ring of the hybrid ceramic ball bearing, and the through hole is arranged on the end face of the bearing mounting hole away from the screw.

8. The twin-screw flowmeter according to claim 7, characterized in that: The twin-screw flowmeter also includes a connecting flange, which is connected to the bearing seat and forms a receiving cavity. The portion of the bearing adjustment seat located outside the through hole and the locking nut are both located in the receiving cavity, and in the axial direction of the connecting flange, the bearing adjustment seat and the connecting flange are spaced apart.

9. The twin-screw flowmeter according to any one of claims 1 to 4, characterized in that: The hybrid ceramic ball bearing connected to the active screw and the hybrid ceramic ball bearing connected to the driven screw are both arranged at intervals in an axial direction perpendicular to the active screw.

10. The twin-screw flowmeter according to any one of claims 1 to 4, characterized in that: The end of the active screw connected to the flow meter is sleeved with a code disk, the flow meter is installed on the metering chamber, and the flow meter and the code disk are connected through a sensor to convert the rotation angle signal of the active screw rotor into a pulse signal.

Images