Piston system structure for a piston pressure gauge with a non-rotating piston

Abstract

The application discloses a piston system structure of a non-rotating piston for a piston pressure gauge, and relates to the technical field of pressure measuring devices.The piston system structure comprises a base, a piston cylinder, a driving device, a vertically arranged first piston rod and a hollow second piston rod.The piston cylinder is arranged in the base and rotationally matched with the base.The driving device can drive the piston cylinder to rotate through a transmission mechanism.The bottom end of the first piston rod extends into the piston cylinder and is slidingly matched with the piston cylinder.The top end of the first piston rod is fixedly connected with a piston which is used for being fixedly connected with a weighing tray.The pressure weighing tray is arranged above the base.The second piston rod is fixedly connected with the base, and the top end of the second piston rod extends into the piston cylinder.The bottom end of the second piston rod is communicated with the liquid outlet of a pressure injection device through a pipeline.The piston system structure can effectively avoid the measurement error caused by the deflection of the piston by driving the piston cylinder to rotate and making the piston not rotate.

Description

Technical Field

[0001] This invention relates to the field of pressure measurement equipment technology, and in particular to a piston system structure for a piston pressure gauge using a non-rotating piston. Background Technology

[0002] Piston gauges are measuring devices that utilize the hydrostatic principle and Pascal's principle to measure physical quantities. As standard pressure generators, they are suitable for pressure measurement and gauge calibration, offering advantages such as high accuracy and stable performance. For details, please refer to the two calibration regulations issued by the State Administration for Market Regulation: "JJG59-2007 Verification Regulation for Piston Gauges" and "JJG59-2022 Verification Regulation for Liquid Piston Gauges".

[0003] Based on the piston assembly structure, piston pressure gauges can be classified into simple pistons, differential pistons, reverse-pressure pistons, and controllable gap pistons. Because the diameter change of the piston rod in a simple piston is much smaller than that of the piston cylinder, the radius of the fluid's neutral plane within the piston gap increases, resulting in a larger effective area, and the pressure deformation coefficient can be theoretically calculated. Furthermore, simple pistons are easy to manufacture and have high sensitivity, thus they are widely used.

[0004] A simple piston system consists of a piston and a piston cylinder. The top of the piston is connected to a weighing tray, which makes it easy to load weights. The piston rod and the load-bearing part are often made as an integral or separate load-bearing tray. This requires the piston to have a specified qualified duration (i.e., the time for the weighing tray to rotate as mentioned in the above procedure).

[0005] The concept behind piston pressure gauges is a static pressure measuring instrument where the piston, maintaining its original foundation without bending or deformation, rotates with minimal friction (sliding friction) due to inertia, perpendicular to the ground, under the physical force of gravity acting on the piston cylinder. Existing simple piston gauges require the piston to rotate while the piston cylinder remains stationary. The purpose of rotating the piston is to evenly adhere the working medium to the contact surface between the piston and piston rod, utilizing the low resistance of the medium for sealing and lubrication. This transforms the piston's movement from static friction to sliding friction, thereby improving measurement accuracy.

[0006] Theoretically, all the pressure weights acting on the piston must be concentric, coaxial, and perpendicular to the ground, and this must remain true while rotating. However, this is difficult to achieve in reality, as the number of weights increases dramatically with pressure. When manually stacking weights, the relative gaps between individual weights and manufacturing errors inevitably cause a shift in the center of gravity of the stacked weight group. Simultaneously, the high-pressure piston, due to its fixed, relatively small area and thin diameter, undergoes rigid deformation during rotation, causing periodic swaying due to instability in the center of gravity. The main reasons for this include the material density distribution of the weights, the concentricity of the weights during processing, the dynamic balancing experiment of the weights, the number of weights, the choice of piston material, the rigidity of the piston, and human factors such as the loading of weights during use. Furthermore, when the piston sways, the pressure per unit area changes, leading to significant fluctuations in the pressure value, and in severe cases, even making data measurement and traceability impossible.

[0007] In actual manufacturing, various methods are employed to maintain the piston's motion characteristics, including hand-fitting the piston, precision machining, increasing the piston's physical area, and reducing the clearance to decrease the oscillation amplitude. The underlying principle is always the same: ensuring the piston rotates smoothly and stably. Addressing the issue of misalignment in weight rotation involves precision machining and material forging to resolve density issues; dynamic balancing tests are required after machining; reducing the clearance between the piston and connecting rod can lead to insufficient piston rigidity, resulting in sliding friction and poor piston rotation, causing irregular fluctuations in readings; addressing insufficient rigidity can lead to a significant increase in weight due to increased area; and stacking weights can cause cumulative concentricity errors and center of gravity shift when there are many weights. Furthermore, from a specification perspective, the commonly used 60MPa piston with an area of ​​0.05cm²... 2 Taking a piston as an example, its diameter is only 2.522mm, requiring a 30kg weight for a 280mm diameter. The difference in weight mass between the lowest grade (0.05%) and the highest grade (0.02%) in the specifications is only 0.3g, and the difference between the lowest grade (0.05%) and the highest grade (0.05%) is only 0.48g. For a common 50mm high piston, if the weight swing angle exceeds 2 minutes, the piston output accuracy will be substandard. Higher pressure piston systems in the specifications use thinner pistons and more weights, demonstrating that piston deformation and weight center of gravity shift have a significant impact on the pressure gauge's output. In short, existing technology struggles to perfectly solve the problem of measurement error fluctuations caused by piston deflection. This is almost an unsolvable, vicious cycle in rotating piston systems, and remains a pressing technical challenge in the field. Summary of the Invention

[0008] The purpose of this invention is to provide a piston system structure for a piston pressure gauge with a non-rotating piston, so as to solve the problems existing in the prior art and avoid measurement errors caused by piston deflection.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] This invention provides a piston system structure for a non-rotating piston in a piston pressure gauge, comprising:

[0011] Base; the base serves as the supporting housing for the piston system;

[0012] Piston cylinder; the piston cylinder is disposed within the base and rotatably engages with the base;

[0013] Drive device: The drive device is capable of driving the piston cylinder to rotate via a transmission mechanism;

[0014] A vertically arranged first piston rod: the bottom end of the first piston rod extends into the piston cylinder and slides with the piston cylinder, and a piston is fixedly connected to the top end of the first piston rod. The piston is used to fix to the weighing tray; the pressure weighing plate is located above the base.

[0015] Hollow second piston rod: The second piston rod is fixedly connected to the base, and the top end of the second piston rod extends into the piston cylinder, while the bottom end of the second piston rod is connected to the liquid outlet of the injection device through a pipeline.

[0016] Preferably, the first piston rod and the second piston rod are coaxial.

[0017] Preferably, the base includes an upper base and a lower base, the upper base being fixedly connected to the lower base by screws; the top of the piston cylinder is rotatably engaged with the upper base by a bearing, and the bottom of the piston cylinder is rotatably engaged with the lower base by a bearing.

[0018] Preferably, the driving device is an electric motor, and the transmission mechanism includes a driving pulley mounted on the output shaft of the driving device, a driven pulley fixedly mounted on the piston cylinder, and a transmission belt wound around the driving pulley and the driven pulley; the lower base is provided with a belt hole for the transmission belt to pass through.

[0019] Preferably, a sealing ring is provided between the bottom end of the piston cylinder and the lower base.

[0020] Preferably, the second piston rod is fixedly connected to the lower base; a pressure-inducing hole is provided on the side of the lower base, and a pressure-inducing channel is provided inside the lower base. One end of the pressure-inducing channel is connected to the pressure-inducing hole, and the other end is connected to the bottom end of the second piston rod. The pressure-inducing hole is connected to the liquid outlet of the injection device through a pipeline.

[0021] Preferably, the piston is slidably engaged with the upper base via a ball bearing.

[0022] Preferably, the upper base is provided with a laser rangefinder for detecting the vertical displacement of the weighing tray; the laser rangefinder, the driving device and the injection device are respectively connected to the control system signal.

[0023] Preferably, a set screw is provided on the side wall of the upper base, and a sleeve is provided at the bottom of the weighing tray. The sleeve is fitted onto the upper base, and there is a gap between the sleeve and the upper base. The sleeve is provided with a vertical groove corresponding to the set screw, and the set screw passes through the groove and slides with the groove.

[0024] Preferably, it also includes an outer protective shell, which is fixedly sleeved on the base, and the weighing pallet cooperates with the outer protective shell through an anti-impact guide bearing.

[0025] The present invention achieves the following technical effects compared to the prior art:

[0026] The piston system structure of the piston pressure gauge of the present invention uses a non-rotating piston to drive the piston cylinder to rotate while keeping the piston from rotating. Adjusting the upper base and adding a ball bearing guide sleeve ensures that the piston's center of gravity is always vertical, and avoids deformation errors caused by insufficient piston rigidity, as well as measurement errors caused by piston rotation and deflection.

[0027] Compared to existing piston pressure gauges with rotating pistons, the piston system structure of the present invention with a non-rotating piston can provide more accurate and controllable vertical gravity force application, resulting in more stable and accurate pressure values, and providing great convenience for traceability in metrology work. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the piston system structure for the non-rotating piston used in the piston pressure gauge of the present invention.

[0030] The components are as follows: 1. Lower base; 2. Upper base; 3. Piston cylinder; 4. Bearing; 5. First piston rod; 6. Piston; 7. Weighing tray; 8. Ball guide bearing; 9. Set screw; 10. Slide groove; 11. Anti-impact guide protection bearing; 12. Outer protective shell; 13. Driven pulley; 14. Transmission belt; 15. Belt hole; 16. Drive pulley; 17. Drive device; 18. Pressure hole; 19. Pressure channel; 20. Laser rangefinder sensor; 21. Second piston rod; 22. Sealing ring; 23. Plug. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide a piston system structure for a piston pressure gauge with a non-rotating piston, so as to solve the problems existing in the prior art and avoid measurement errors caused by piston deflection.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, this embodiment provides a piston system structure for a non-rotating piston in a piston pressure gauge, including a base, a piston cylinder 3, a drive device 17, a first piston rod 5, and a second piston rod 21.

[0035] The base serves as the supporting housing for the piston system, and the piston cylinder 3 is disposed within the base and rotatably engaged with the base. In this embodiment, the base includes an upper base 2 and a lower base 1, with the upper base 2 fixedly connected to the lower base 1 by screws. The top of the piston cylinder 3 is rotatably engaged with the upper base 2 via a bearing 4, and the bottom of the piston cylinder 3 is rotatably engaged with the lower base 1 via a bearing 4.

[0036] In this embodiment, a sealing ring 22 is provided between the bottom end of the piston cylinder 3 and the lower base 1.

[0037] The drive device 17 can drive the piston cylinder 3 to rotate through the transmission mechanism. In this embodiment, the drive device 17 is an electric motor. The transmission mechanism includes a drive pulley 16 mounted on the output shaft of the drive device 17, a driven pulley 13 fixedly mounted on the piston cylinder 3, and a transmission belt 14 wound around the drive pulley 16 and the driven pulley 13. The lower base 1 is provided with a belt hole 15 for the transmission belt 14 to pass through.

[0038] The first piston rod 5 is vertically arranged, and the bottom end of the first piston rod 5 extends into the piston cylinder 3 and slides with the piston cylinder 3. The top end of the first piston rod 5 is fixedly connected to the piston 6, which is used to fix to the weighing tray 7; the pressure weighing plate is located above the base.

[0039] The second piston rod 21 is hollow and fixed to the base. The top end of the second piston rod 21 extends into the piston cylinder 3, and the bottom end of the second piston rod 21 is connected to the liquid outlet of the injection device through a pipeline. The injection device is a commonly used existing device in this field, and will not be described in detail here.

[0040] In this embodiment, the first piston rod 5 and the second piston rod 21 are coaxial; the second piston rod 21 is fixedly connected to the lower base 1; a pressure-inducing hole 18 is provided on the side of the lower base 1, and a pressure-inducing channel 19 is provided inside the lower base 1. One end of the pressure-inducing channel 19 is connected to the pressure-inducing hole 18, and the other end is connected to the bottom end of the second piston rod 21. The pressure-inducing hole 18 is connected to the liquid outlet of the injection device through a pipeline. A plug 23 is also provided in the lower base 1. The plug 23 is used for turning the pressure-inducing channel 19 and sealing the connection between the bottom end of the second piston rod 21 and the pressure-inducing channel 19.

[0041] In this embodiment, the piston 6 is slidably coupled to the upper base 2 via a ball bearing guide bearing 8.

[0042] In this embodiment, a laser rangefinder 20 for detecting the vertical displacement of the weighing tray 7 is provided on the upper base 2; the laser rangefinder 20, the drive device 17 and the injection device are respectively connected to the control system signal.

[0043] In this embodiment, a top screw 9 is provided on the side wall of the upper base 2, and a sleeve is provided at the bottom of the weighing tray 7. The sleeve is fitted onto the upper base 2, and there is a gap between the sleeve and the upper base 2. The sleeve is provided with a vertical groove 10 corresponding to the top screw 9, and the top screw 9 passes through the groove 10 and slides with the groove 10.

[0044] The piston system structure of the piston pressure gauge using a non-rotating piston in this embodiment also includes an outer protective shell 12, which is fixedly sleeved on the base. The weighing tray 7 is engaged with the outer protective shell 12 through an anti-impact guide protection bearing 11.

[0045] The working principle of the piston system structure with a non-rotating piston in this embodiment of the piston pressure gauge is as follows:

[0046] When the weight is placed on the weighing tray 7, the control system controls the injection device to inject pressure through the pressure inlet 18. The liquid passes through the second piston rod 21, introducing pressure into the piston cylinder 3. Simultaneously, the piston cylinder 3 begins to rotate under the action of an external motor. When the pressure inside the piston cylinder 3 is greater than the ratio of the weight of the weight to the area of ​​the piston 6 (P_cylinder > P_piston 6), the piston 6 floats upward. The laser rangefinder 20 detects the movement of the weighing tray 7. At this time, the control system controls and adjusts the injection pressure of the injection device so that (P_cylinder = P_piston 6), allowing the piston 6 to remain at the required height, thereby completing the calibration of the pressure value of the injection device. The laser rangefinder 20 detects the position signal and sends it to the control system for position control. This ensures that the working position is the position last measured, guaranteeing the reproducibility of the piston 6 data.

[0047] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A piston system structure for a piston pressure gauge using a non-rotating piston, characterized in that, include: Base; The base serves as the supporting housing for the piston system; Piston cylinder; The piston cylinder is disposed within the base and is rotatably engaged with the base; Drive device: The drive device is capable of driving the piston cylinder to rotate via a transmission mechanism; A vertically arranged first piston rod: the bottom end of the first piston rod extends into the piston cylinder and slides with the piston cylinder, and a piston is fixedly connected to the top end of the first piston rod. The piston is used to fix to the weighing tray; the pressure weighing plate is located above the base. A hollow second piston rod: The second piston rod is fixedly connected to the base, and the top end of the second piston rod extends into the piston cylinder. The bottom end of the second piston rod is connected to the liquid outlet of the injection device through a pipeline. The base includes an upper base and a lower base. The upper base is fixedly connected to the lower base by screws. The top of the piston cylinder is rotatably engaged with the upper base through a bearing, and the bottom of the piston cylinder is rotatably engaged with the lower base through a bearing. The driving device is a motor. The transmission mechanism includes a driving pulley mounted on the output shaft of the driving device, a driven pulley fixedly sleeved on the piston cylinder, and a transmission belt wound around the driving pulley and the driven pulley. The lower base is provided with a belt hole for the transmission belt to pass through.

2. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: The first piston rod is coaxial with the second piston rod.

3. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: A sealing ring is provided between the bottom end of the piston cylinder and the lower base.

4. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: The second piston rod is fixedly connected to the lower base; a pressure-inducing hole is provided on the side of the lower base, and a pressure-inducing channel is provided inside the lower base. One end of the pressure-inducing channel is connected to the pressure-inducing hole, and the other end is connected to the bottom end of the second piston rod. The pressure-inducing hole is connected to the liquid outlet of the injection device through a pipeline.

5. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: The piston is slidably fitted to the upper base via a ball bearing.

6. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: The upper base is equipped with a laser rangefinder sensor for detecting the vertical displacement of the weighing tray; the laser rangefinder sensor, the driving device, and the injection device are respectively connected to the control system signal.

7. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: A set screw is provided on the side wall of the upper base, and a sleeve is provided at the bottom of the weighing tray. The sleeve is fitted onto the upper base, and there is a gap between the sleeve and the upper base. The sleeve is provided with a vertical groove corresponding to the set screw, and the set screw passes through the groove and slides with the groove.

8. The piston system structure for a non-rotating piston in a piston pressure gauge according to claim 1, characterized in that: It also includes an outer protective shell, which is fixedly sleeved on the base, and the weighing pallet cooperates with the outer protective shell through an anti-impact guide and protection bearing.

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