Differential pressure detection device and multi-parameter transmitter detection equipment

Abstract

The present invention provides a differential pressure detection device and multi-parameter transmitter detection equipment, belonging to the field of pressure measurement technology. The differential pressure detection device includes a pressure cylinder, a differential pressure piston, a first piston rod, a flywheel, a stopper, a shifter, a drive mechanism, and a load assembly. The multi-parameter transmitter detection equipment includes the aforementioned differential pressure detection device, a static pressure module, and a pressure delivery system. The present invention can improve the accuracy of differential pressure detection, and in particular, can better detect multi-parameter transmitters.

Description

Technical Field

[0001] The present invention belongs to the technical field of pressure measurement, and more specifically, relates to a differential pressure detection device and a multi-parameter transmitter detection equipment. Background Art

[0002] Multi-parameter transmitters are a type of sensing device widely used in industries such as chemical, energy, pharmaceutical, and food. They utilize composite sensing technology and can simultaneously measure three different process parameters: differential pressure, static pressure, and temperature. This reduces the size and structural complexity of the measurement system, increases reliability, and reduces manufacturing costs by 30%-40%. Through built-in flow calculation, correction, and integration modules, they perform internal compensation for differential pressure, static pressure, and temperature, improving the accuracy of the measured medium quality and volume flow measurement results. Their modular structure supports various process connections and multiple communication protocols. Multi-parameter transmitters require testing and calibration before use to determine whether their test results meet the requirements. However, there is no high-precision detection device for this type of transmitter among the known detection devices at home and abroad. The actual working status of this type of transmitter cannot be reproduced in actual detection work. Both the working pressure value within the design range and the multi-point differential pressure values ​​within the design range are given at the same time. That is, when detecting the measurement accuracy of the pressure channel, the measurement accuracy of the differential pressure and flow channels cannot be detected. The temperature and pressure input signals can only be changed to a fixed mode through the configuration software. The measurement performance of the differential pressure and flow channels can be detected in the absence of static pressure and temperature signals, which cannot correctly and comprehensively reflect the technical parameter indicators of the entire set of multi-parameter transmitters.

[0003] Currently, in terms of differential pressure detection alone, existing methods make it difficult to accurately detect and calibrate the differential pressure of multi-parameter transmitters.

[0004] Currently, the most accurate way to measure differential pressure is to use a piston-type pressure gauge. A piston is located within a pressure cylinder, dividing the cylinder into two compartments, upper and lower. These compartments are connected to gas ports on either side of the device being tested via pipes. The piston moves within the cylinder under the influence of differential pressure, and the specific value is transmitted through a connecting rod that runs through the cylinder and connects to the piston in the form of force and displacement. However, friction between the piston, piston rod, and cylinder can affect measurement accuracy, and even applying lubricant to the inner wall of the cylinder is difficult to improve significantly.

[0005] In order to solve the above problems, we designed a differential pressure detection device and a multi-parameter transmitter detection equipment specifically used for detecting multi-parameter transmitters. Summary of the Invention

[0006] The object of the present invention is to provide a differential pressure detection device and a multi-parameter transmitter detection device to solve the problem that the existing technology cannot meet the demand for high-precision pressure differential pressure detection.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a differential pressure detection device, including a pressure cylinder, a differential pressure piston, a first piston rod, a flywheel, a stopper, a dial, a driving mechanism and a load assembly; a sliding cavity is provided inside the pressure cylinder, and a first connecting interface, a second connecting interface and a first lubricating oil interface are also provided on the pressure cylinder; the differential pressure piston is slidingly arranged in the sliding cavity and is sealed with the inner wall of the pressure cylinder to separate the sliding cavity into a first chamber and a second chamber, the first connecting interface is connected to the first chamber, the second connecting interface is connected to the second chamber, and the first lubricating oil interface is connected to the middle of the sliding cavity; one end of the first piston rod is connected to the differential pressure piston, and the other end passes through the pressure cylinder and is slidingly sealed with the pressure cylinder; the flywheel is rotatably arranged on the pressure cylinder, and is sleeved On the first piston rod; the stopper is fixedly arranged on the flywheel; the shifter is fixedly arranged on the first piston rod and is in an intersecting state with the stopper at a spatial angle, and is used to abut against the stopper when the flywheel rotates and has sliding freedom to drive the first piston rod to rotate; the driving mechanism is connected to the flywheel in a transmission manner to give the flywheel an initial velocity of rotation; the load assembly is arranged on the first piston rod, and is used to apply an axial load to the first piston rod; the driving mechanism includes a guide rail, a cylinder, a rack and a gear ring; the guide rail is used to be fixed relative to the pressure cylinder; the cylinder is arranged on the guide rail; the rack is slidably arranged on the guide rail and is connected to the cylinder to slide on the guide rail driven by the cylinder; the gear ring is arranged on the flywheel and meshes with the rack; wherein, the rack separates from the gear ring after moving to a preset position.

[0008] The differential pressure detection device provided by the present invention has the following beneficial effects: Compared with the prior art, the present invention provides an initial velocity for the flywheel to rotate through a driving mechanism. When the flywheel rotates, the stopper and the shifter act as a limiter, allowing the flywheel to continue to drive the first piston rod and the differential pressure piston to rotate, resulting in relative rotation between the first piston rod, the differential pressure piston, and the pressure cylinder. This allows the lubricating oil entering the first lubricating oil interface to be fully and evenly distributed between the first piston rod, the differential pressure piston, and the pressure cylinder, reducing friction while maintaining dynamic friction between the first piston rod, the differential pressure piston, and the pressure cylinder, thereby improving the sensitivity of the piston movement. Subsequently, as the flywheel rotation speed gradually decreases, the power transmission between the stopper and the shifter disappears, eliminating the effect of friction between the stopper and the shifter on the movement of the differential pressure piston. At this point, the differential pressure piston is not affected by either starting friction or other external frictional forces, maintaining a high accuracy. Furthermore, the differential pressure can be calculated based on the load amount of the load assembly and the sliding distance of the differential pressure piston. In this way, more accurate differential pressure detection can be achieved, thereby obtaining more precise differential pressure detection data.

[0009] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a multi-parameter transmitter detection device, including the above-mentioned differential pressure detection device, static pressure module and pressure delivery system; the static pressure module is used to generate static pressure or gauge pressure; the pressure delivery system is connected to the differential pressure detection device and the static pressure module respectively, and is provided with an interface component for connecting to the multi-parameter transmitter to be measured, for delivering pressure through a gas medium.

[0010] The beneficial effect of the multi-parameter transmitter detection equipment provided by the present invention is that compared with the existing technology, the present invention organically combines the function of the differential pressure piston to accurately detect the differential pressure performance of the multi-parameter transmitter being measured with the ability of the general piston to meet multiple measurement requirements such as absolute pressure and gauge pressure through the integrated integrated design of the differential pressure detection device and the static pressure module. While optimizing the overall structure, it effectively reduces the volume of the device, shortens the pressure transmission path, and reduces the error in the pressure transmission process, so that the differential pressure detection device in the present invention can efficiently and accurately complete the detection work of the multi-parameter transmitter under different pressure parameters, greatly improving the detection efficiency and reliability, and can meet diverse and high-precision detection needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 A schematic diagram of the position structure of a differential pressure detection device provided by one embodiment of the present invention;

[0013] Figure 2 A schematic diagram of the position structure of a load assembly, a stopper, a flywheel, a shifter, and a pressure cylinder provided in one embodiment of the present invention;

[0014] Figure 3 A schematic diagram of the position structure of a drive mechanism and a flywheel provided in one embodiment of the present invention;

[0015] Figure 4 A schematic structural diagram of a branch oil circuit system provided in another embodiment of the present invention;

[0016] Figure 5 A schematic diagram of the position structure of the upper cylinder cover, the second branch oil circuit, and the second oil channel provided in another embodiment of the present invention;

[0017] Figure 6 A schematic structural diagram of a lower cylinder head, a third branch oil circuit, a fourth branch oil circuit, and a third oil channel provided in another embodiment of the present invention;

[0018] Figure 7 A schematic diagram of the position structure of a cylinder, a first branch oil circuit, and a first oil channel provided in another embodiment of the present invention;

[0019] Figure 8 For the present invention Figure 4 Schematic diagram of the structure at A in the middle;

[0020] Figure 9 A schematic structural diagram of a multi-parameter transmitter detection device provided in yet another embodiment of the present invention;

[0021] Among them, the reference numerals in the figures are as follows:

[0022] 10. Differential pressure detection device; 11. Pressure cylinder; 110. Cylinder barrel; 111. First chamber; 112. Second chamber; 113. First communication port; 114. Second communication port; 115. First lubricating oil port; 116. Upper cylinder head; 117. Lower cylinder head; 118. Sliding seal;

[0023] 12. Differential pressure piston;

[0024] 13. First piston rod;

[0025] 14. Flywheel; 140. Driving mechanism; 141. Guide rail; 142. Cylinder; 143. Rack; 144. Ring gear;

[0026] 15. Blocking piece; 151. Blocking piece;

[0027] 16. shift piece; 161. shift lever; 162. pulley;

[0028] 17. Load assembly; 171. Ballast tray; 172. Calibration object; 173. Mounting tray;

[0029] 18. Second piston rod;

[0030] 19. Branch oil circuit system; 191. First branch oil circuit; 192. First oil channel; 193. Second branch oil circuit; 194. Second oil channel; 195. Third branch oil circuit; 196. Fourth branch oil circuit; 197. Third oil channel;

[0031] 20. Static pressure module;

[0032] 30. Pressure delivery system; 31. Air source assembly; 32. First air path; 33. Third air path; 34. Second air path; 35. Fourth air path; 36. Fifth air path; 37. One-way fluid buffer; 38. Sixth air path; 321. First control valve; 331. Third control valve; 332. Sixth control valve; 351. Fifth control valve; 341. Second control valve; 381. Fourth control valve;

[0033] 40. Measured multi-parameter transmitter;

[0034] 50. Lubrication system; 51. Oil cup; 52. First oil circuit; 53. Second oil circuit; 54. Air pressure balance line;

[0035] 60. Liquid discharge mechanism; 61. Elastic drain pipe; 62. External drain pipe; 63. Seventh control valve; 64. Thin-wall section. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the described embodiments are only part of the embodiments of this application, rather than all the embodiments, and the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] It should be further explained that the drawings and implementation methods of the present invention mainly describe the concept of the present invention. On the basis of this concept, the specific forms and settings of some connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, on the premise that those skilled in the art understand the concept of the present invention, those skilled in the art can implement the above-mentioned specific forms and settings in a well-known manner.

[0038] When an element is referred to as being “fixed to” or “disposed on” another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0039] The directional words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. The terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate the directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0040] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, and "several" means one or more, unless otherwise specifically defined.

[0041] A differential pressure detection device and a multi-parameter transmitter detection device provided by the present invention are now described.

[0042] The first embodiment of the present invention provides a differential pressure detection device, including a pressure cylinder 11, a differential pressure piston 12, a first piston rod 13, a flywheel 14, a stopper 15, a shifter 16, a drive mechanism 140 and a load assembly 17; a sliding cavity is provided inside the pressure cylinder 11, and a first communication interface 113, a second communication interface 114 and a first lubricating oil interface 115 are also provided on the pressure cylinder 11; the differential pressure piston 12 is slidably arranged in the sliding cavity and is sealed with the inner wall of the pressure cylinder 11 to separate the sliding cavity into a first chamber 111 and a second chamber 112, the first communication interface 113 is communicated with the first chamber 111, the second communication interface 114 is communicated with the second chamber 112, and the first lubricating oil interface 115 is communicated with the sliding cavity. The first piston rod 13 is connected to the differential pressure piston 12 at one end, and the other end passes through the pressure cylinder 11 and is slidingly sealed with the pressure cylinder 11; the flywheel 14 is rotatably set on the pressure cylinder 11 and is sleeved on the first piston rod 13; the stopper 15 is fixedly set on the flywheel 14; the shifter 16 is fixedly set on the first piston rod 13, and is in an intersecting state with the stopper 15 having a spatial angle, and is used to abut against the stopper 15 when the flywheel 14 rotates and has sliding freedom to drive the first piston rod 13 to rotate; the driving mechanism 140 is transmission-connected to the flywheel 14 to give the flywheel 14 an initial velocity of rotation; the load assembly 17 is provided on the first piston rod 13, and is used to apply an axial load to the first piston rod 13. Among them, the shifter 16 and the stopper 15 are in a cross state with a spatial angle, which means that the shifter 16 and the stopper 15 can form an angle when they contact each other and thus abut against each other, so as to transmit the rotation from the flywheel 14 to the first piston rod 13 and the differential pressure piston 12, but it does not affect the sliding between the shifter 16 and the stopper 15, and also facilitates the separation between the shifter 16 and the stopper 15, that is, the above-mentioned device is used to abut against the stopper 15 when the flywheel 14 rotates and has the freedom to slide.

[0043] When in use, it is mainly divided into the following two stages.

[0044] In the first stage, the gas interfaces on both sides of the transmitter waiting for detection equipment are first connected to the first communication interface 113 and the second communication interface 114 through pipelines and ventilated. Then, the flywheel 14 is given an initial rotational velocity by the driving mechanism 140. As the flywheel 14 rotates, the limiting action between the stopper 15 and the shifter 16 causes the flywheel 14 to continue to drive the first piston rod 13 and the differential pressure piston 12 to rotate, causing relative rotation between the first piston rod 13 and the differential pressure piston 12 and the pressure cylinder 11. This allows the lubricating oil entering the first lubricating oil interface 115 to be fully and evenly distributed between the first piston rod 13 and the differential pressure piston 12 and the pressure cylinder 11, reducing friction while maintaining a state of dynamic friction between the first piston rod 13 and the differential pressure piston 12 and the pressure cylinder 11, thereby improving the sensitivity of the piston movement. At this time, the differential pressure piston 12 moves in the sliding cavity of the pressure cylinder 11 under the action of the differential pressure on both sides. At the same time, the first piston rod 13 is loaded or unloaded through the load component 17 to limit the sliding amount of the differential pressure piston 12, thereby preventing the sliding amount of the differential pressure piston 12 from exceeding the stroke, making the differential pressure data difficult to measure.

[0045] In existing methods, the process of piston movement driven by differential pressure during testing changes from static friction to kinetic friction and then back to static friction. The starting friction force when static friction changes to kinetic friction is slightly greater than the kinetic friction force, making it difficult to improve the sensitivity of piston movement. In the present application, however, dynamic friction is always maintained between the first piston rod 13 and the differential pressure piston 12 and the pressure cylinder 11 during the testing process. The entire testing process is unaffected by the starting friction force, thereby improving the sensitivity of the piston movement.

[0046] In addition, due to the cooperation between the stopper 15 and the shifter 16, when the flywheel 14 drives the first piston rod 13 and the differential pressure piston 12 to rotate, the sliding of the differential pressure piston 12 and the first piston rod 13 is not excessively restricted.

[0047] In the second stage, the rotational speed of flywheel 14 gradually decreases, causing the power transmission between block 15 and selector 16 to disappear. Specifically, the pressure between block 15 and selector 16 disappears, or the block 15 and selector 16 separate. This eliminates the friction between block 15 and selector 16 that affects the movement of differential pressure piston 12. At this point, first piston rod 13 and differential pressure piston 12 continue to rotate due to inertia. Under the influence of the differential pressure on both sides, differential pressure piston 12 can continue to move within pressure cylinder 11. At this point, differential pressure piston 12 is unaffected by starting friction or other external frictional forces, maintaining high accuracy. The sliding distance of differential pressure piston 12 can be read from the travel distance of the exposed end of first piston rod 13. The differential pressure can then be calculated based on the load applied by load assembly 17 and the sliding distance of differential pressure piston 12.

[0048] like Figures 1 to 7 As shown, in some specific embodiments, the differential pressure detection device 10 of the present invention is used to detect differential pressures of the order of 0.1 kPa-400 kPa. The differential pressure detection device 10 achieves high-precision pressure control through the coordinated design of the mechanical structure and the load component 17. The sliding cavity inside the pressure cylinder 11 is divided into an independent first chamber 111 and a second chamber 112 by the differential pressure piston 12. The first communication interface 113 is connected to the first chamber 111 for connecting to a differential pressure detection instrument, and the second communication interface 114 is connected to the second chamber 112 for connecting to an external static pressure source. The differential pressure piston 12 is driven by the first piston rod 13 to move along its axial direction. Specifically, the axial movement of the differential pressure piston 12 is achieved by the rotation of the flywheel 14: when the stopper 15 on the flywheel 14 abuts the shifter 16 on the first piston rod 13, the rotational movement of the flywheel 14 is converted into a linear displacement of the differential pressure piston 12, and the rotation of the flywheel 14 is driven by the drive mechanism 140. The axial load applied to the first piston rod 13 is changed by adjusting the load assembly 17. When positive loading is applied, the differential pressure piston 12 is pushed to compress the second chamber 112 to generate a positive pressure differential (0-100 kPa). When negative unloading is applied, the differential pressure piston 12 is retracted to expand the second chamber 112 to generate a negative pressure differential (0- -50kPa). The first lubricating oil interface 115 injects lubricating medium into the middle of the sliding cavity to form a dynamic oil film to suppress friction interference and ensure the long-term stability of the differential pressure signal.

[0049] The differential pressure piston 12 and first piston rod 13 can be made of tungsten carbide, which has a hardness of ≥90 HRA and a thermal linear expansion coefficient of ≤1.5×10⁻⁶ / °C, ensuring negligible deformation. Furthermore, these materials are lightweight. Theoretically, when the differential pressure piston 12 has a diameter of 1 cm and a height of 8 cm, it generates a pressure of approximately 6 kPa. Considering factors such as lightweight design and material optimization in actual operating conditions, the mass of the differential pressure piston 12 and first piston rod 13 is expected to be further reduced, thereby reducing the overall pressure generated. Furthermore, since there is a lower pressure limit during measurement, if the lower limit is relatively large, it can compensate for the weight of the differential pressure piston 12 and first piston rod 13. If the lower limit is too small to compensate, lighter materials such as titanium alloys or ceramics can be used, or a hollow structure can be adopted to reduce the weight of the differential pressure piston 12 and first piston rod 13.

[0050] It is worth noting that the first connecting interface 113 and the second connecting interface 114 are not arranged at the two ends of the pressure cylinder 11. When the movement of the differential pressure piston 12 exceeds its preset range, the differential pressure piston 12 will block the corresponding air path, which causes part of the gas to be compressed. The compressed gas will form an air cushion at this position. The formed air cushion will prevent the differential pressure piston 12 from directly impacting the upper and lower ends of the pressure cylinder 11, thereby reducing the risk of the differential pressure piston 12 being hit and deformed.

[0051] Compared to existing technologies, this invention improves differential pressure resolution to 0.01 kPa by utilizing a drive mechanism 140 to drive the flywheel 14 and a mechanical loading mechanism of the load assembly 17. It also supports stepless switching between positive pressure (0-100 kPa) and negative pressure (0-50 kPa), enabling bidirectional differential pressure detection. For example, when generating a 0.1 kPa differential pressure at a static pressure of 15 MPa, the repeatability error is ≤ ±0.03 kPa, a 20-fold improvement in accuracy compared to conventional solutions.

[0052] The existing differential pressure detection device 10 suffers from differential pressure drift due to sliding friction between the piston and cylinder 110, resulting in a low signal-to-noise ratio (SNR) in the micro differential pressure range. The present invention utilizes dynamic oil film lubrication technology to reduce the friction coefficient from 0.1 (dry friction) to below 0.001. Combined with the wear resistance of tungsten carbide, the differential pressure drift remains below ±0.02% after 1000 hours of continuous operation, and the SNR in the micro differential pressure range is increased to 60dB, significantly outperforming conventional solutions.

[0053] like Figure 3 As shown, a differential pressure detection device according to a first embodiment of the present invention comprises a drive mechanism 140 comprising a guide rail 141, a cylinder 142, a rack 143, and a ring gear 144. The guide rail 141 is fixed relative to the pressure cylinder 11. The cylinder 142 is mounted on the guide rail 141. The rack 143 is slidably mounted on the guide rail 141 and connected to the cylinder 142, so as to slide on the guide rail 141 driven by the cylinder 142. The ring gear 144 is mounted on the flywheel 14 and meshes with the rack 143. The rack 143 separates from the ring gear 144 after moving to a predetermined position. The flywheel 14 is cylindrical in structure. The stopper 15 comprises a stopper 151 vertically mounted at the bottom of the flywheel 14. The shifter 16 comprises a shifter rod 161 vertically mounted on the first piston rod 13. A pulley 162 is provided on the shifter rod 161 at a position that contacts the stopper 151 to reduce friction.

[0054] The operator can drive the flywheel 14 manually or by motor drive. The knurled design on the edge of the flywheel 14, which can be considered a drive mechanism 140, facilitates manual rotation. Furthermore, a belt groove is provided on the edge of the flywheel 14, which is driven by a motor via a belt drive. These two drive methods meet different usage requirements. Another embodiment of the drive mechanism 140 driving the flywheel 14 is as follows.

[0055] The rotation of the flywheel 14 is realized by the cylinder 142, the rack 143, the ring gear 144 and the guide rail 141. The ring gear 144 is sleeved on the outer ring of the flywheel 14. A rack 143 meshing with the ring gear 144 is provided on one side of the ring gear 144. When the rack 143 reciprocates and contracts under the drive of the cylinder 142, the flywheel 14 can realize the rotation in both positive and negative directions. In order to allow the rack 143 to reciprocate and contract stably, a guide rail 141 is also provided. The rack 143 is slidably connected to the guide rail 141. The cylinder 142 is provided on the far side of the guide rail 141. From one end of the flywheel 14, the piston rod end of the cylinder 142 is connected to one end of the rack 143, and the other end of the rack 143 extends toward the flywheel 14 and engages with the ring gear 144. When the cylinder 142 is extended or retracted, the flywheel 14 can be driven to rotate by the extension or retraction of the rack 143. After the rack 143 moves to a preset position, it separates from the ring gear 144. The rack 143 actively disengages from the ring gear 144 at the preset position, cutting off power transmission and avoiding reverse impact. The flywheel 14 rotates to a slow stop under the action of inertia.

[0056] A scale is vertically set on the side wall of the flywheel 14, and a pointer is also set on the first piston rod 13. The pointer is located above the lever 161. The pointer can be used to determine the height of the rise or fall of the differential pressure piston 12, and then the size of the change in pressure in the first chamber 111 or the second chamber 112 can be obtained.

[0057] By operating the drive mechanism 140, the position of the differential pressure piston 12 within the sliding cavity is changed, thereby changing the pressure within the first chamber 111 or the second chamber 112. The drive mechanism 140 controls the rotational movement of the flywheel 14. The flywheel 14 is rotatably mounted at the top of the pressure cylinder 11. A bearing is provided between the pressure cylinder 11 and the flywheel 14 to ensure continuous rotation of the flywheel 14. The flywheel 14 is a cylindrical structure with two symmetrically positioned baffles 15 at its bottom edge. Each baffle 15 includes a baffle 151 vertically disposed at the bottom of the flywheel 14. When the flywheel 14 rotates, the baffles 151 at the bottom of the flywheel 14 also rotate. During the rotation of the baffles 151, the pulley 162 contacts the baffle 151 on the corresponding side. The baffle 151 only generates horizontal thrust on the shifter 16, converting the rotational movement of the flywheel 14 into the vertical movement of the first piston rod 13 and the differential pressure piston 12. This design replaces sliding friction with rolling friction, significantly reducing the resistance of the differential pressure piston 12 and the first piston rod 13 when they move up and down.

[0058] like Figures 2 to 4 As shown, a differential pressure detection device is provided in the first embodiment of the present invention, the pressure cylinder 11 is vertically arranged, and the axial length of the differential pressure piston 12 does not exceed half of the stroke of the differential pressure piston 12 in the sliding cavity; the upper surface of the differential pressure piston 12 is connected to the lower end of the first piston rod 13, and the lower surface of the differential pressure piston 12 is provided with a second piston rod 18, and the lower end of the second piston rod 18 passes through the pressure cylinder 11 and is slidingly sealed with the pressure cylinder 11; the load assembly 17 includes a ballast tray 171, a calibration object 172 and a mounting tray 173; the ballast tray 171 is arranged above the pressure cylinder 11 and is connected to the upper end of the first piston rod 13, for placing the calibration object 172; the mounting tray 173 is arranged below the pressure cylinder 11 and is connected to the lower end of the second piston rod 18, for mounting the calibration object 172.

[0059] The differential pressure detection device 10 of the present invention adopts a vertical layout design, and the axial length of the differential pressure piston 12 is designed to be 40% of its maximum stroke in the sliding cavity to prevent the differential pressure piston 12 from tilting and getting stuck at the extreme position.

[0060] An embodiment of the load assembly 17 is as follows: the load assembly 17 is composed of a ballast tray 171, a mounting tray 173 and a calibration object 172. The ballast tray 171 is firmly mounted on the top of the pressure cylinder 11 through a threaded or flange structure, and is rigidly connected to the upper end of the first piston rod 13 to ensure vertical force transmission; the mounting tray 173 is fixed to the bottom of the pressure cylinder 11 through the same connection method, and is connected to the lower end of the second piston rod 18. Both are made of high-strength alloy materials, and the surface is treated for wear resistance, and can withstand long-term and frequent pressure loading. The calibration object 172 can be a weight, and the weight can be selectively placed on the ballast tray 171 or the mounting tray 173. By changing the number or weight of the weights, different pressures can be generated, including positive pressure and negative pressure; after the weights are loaded, the first piston rod 13 is driven to drive the differential pressure piston 12 to move, and the pressure in the sliding cavity at the upper and lower ends of the differential pressure piston 12 changes;

[0061] Another embodiment of the load assembly 17 is as follows: the load assembly 17 is composed of a ballast tray 171 and a calibration object 172, and the ballast tray 171 has the characteristic of being reversible for use.

[0062] The differential pressure detection device 10 is used to detect differential pressure. A sliding cavity is provided inside the pressure cylinder 11. The differential pressure piston 12 is slidably provided in the sliding cavity and is sealed with the inner wall of the pressure cylinder 11 to separate the sliding cavity into a first chamber 111 and a second chamber 112; the lower end of the first piston rod 13 is connected to the differential pressure piston 12, and the upper end passes through the pressure cylinder 11 and is slidably and sealed with the pressure cylinder 11. A ballast tray 171 is provided at the upper end of the first piston rod 13.

[0063] In the positive pressure mode, the ballast tray 171 is arranged above the pressure cylinder 11 for placing the calibration object 172. At this time, the differential pressure piston 12 moves in the sliding cavity to achieve positive pressure detection.

[0064] When switching to negative pressure mode is necessary, there are two ways to do this. The first involves flipping the ballast tray 171. With the aid of a bracket, the pressure cylinder 11 is connected to the bracket's rotating shaft. By flipping the pressure cylinder 11 180°, the ballast tray 171 is also inverted, causing the ballast tray 171, originally located above the pressure cylinder 11, to flip downward. At this point, the position at which the ballast tray 171 is connected to the first piston rod 13 also changes accordingly, and the calibration object 172 is placed on the flipped ballast tray 171. This flipping operation changes the force applied to both ends of the differential pressure piston 12, enabling negative pressure detection.

[0065] Another way is not to flip the ballast tray 171, but to achieve negative pressure detection by simply exchanging the positive and negative pressure detection pipelines. Specifically, by changing the flow direction of the gas medium, the direction of the pressure difference at both ends of the differential pressure piston 12 is changed, thereby achieving negative pressure detection. In this way, the position of the ballast tray 171 remains unchanged, and the mode conversion is achieved by switching the pipeline, which reduces the operational complexity and potential wear caused by mechanical flipping, while also ensuring the accuracy and stability of the detection. Through the above-mentioned two negative pressure mode implementation methods, the load assembly 17 of this embodiment can flexibly switch between positive pressure and negative pressure modes to meet diverse detection needs.

[0066] like Figures 4 to 7 As shown, a differential pressure detection device is provided in the first embodiment of the present invention, wherein a first oil hole and a first oil channel 192 corresponding to the sliding surface of the differential pressure piston 12 are provided in the middle of the pressure cylinder 11; a second oil hole and a second oil channel 194 corresponding to the sliding surface of the first piston rod 13 are provided at the upper end of the pressure cylinder 11; a third oil hole and a third oil channel 197 corresponding to the sliding surface of the second piston rod 18 are provided at the lower end of the pressure cylinder 11; the first oil hole and the first oil channel 192, the second oil hole and the second oil channel 194, the third oil hole and the third oil channel 197 are all connected to the first lubricating oil interface 115, and the lubricating medium is supplied to the corresponding sliding surfaces through the internal branch oil circuit system 19.

[0067] The internal sliding cavity of the pressure cylinder 11 provides sliding space for the differential pressure piston 12, the first piston rod 13, and the second piston rod 18. Specifically, the first oil hole communicates with an annular first oil passage 192 defined within the wall of the pressure cylinder 11. This first oil passage 192 surrounds the center of the pressure cylinder 11 and is positioned directly above the sliding area of ​​the differential pressure piston 12, ensuring that lubricating medium is delivered directly to the contact surface between the differential pressure piston 12 and the inner wall of the pressure cylinder 11.

[0068] A second oil hole and a second oil passage 194 are provided at the upper end of the pressure cylinder 11. The second oil hole is connected to the second oil passage 194, and the exit of the second oil passage 194 precisely corresponds to the sliding surface where the first piston rod 13 exits the pressure cylinder 11, ensuring that the lubricating medium can accurately lubricate the sliding seal between the first piston rod 13 and the pressure cylinder 11. Similarly, a third oil hole and a third oil passage 197 are provided at the lower end of the pressure cylinder 11. The third oil hole and the third oil passage 197 are connected, allowing the lubricating medium to flow through the third oil hole and the third oil passage 197 to the area where the second piston rod 18 slides in contact with the lower end of the pressure cylinder 11.

[0069] A first lubricating oil port 115, serving as an inlet for external lubricating media, is located at the lower end of the pressure cylinder 11. This port connects to the first, second, and third oil holes, as well as the first, second, and third oil passages 192, 194, and 197, respectively, through an internal branch oil system 19. Specifically, lubricating media enters the first lubricating oil port 115 and flows in parallel into the first, second, and third oil passages 192, 194, and 197, ultimately reaching the corresponding sliding surfaces for efficient lubrication.

[0070] This design of setting multiple groups of oil holes and oil channels on the pressure cylinder 11 and realizing unified oil supply through the first lubricating oil interface 115 has significant beneficial effects. First, the oil holes and oil channels are independently set for the sliding surfaces of different positions of the differential pressure piston 12, the first piston rod 13 and the second piston rod 18. It is possible to accurately distribute the lubricating medium according to the working characteristics and lubrication requirements of each component, effectively reduce sliding friction, reduce component wear, and extend the service life of the differential pressure detection device 10. Secondly, the connection design of the internal branch oil circuit system 19 and the first lubricating oil interface 115 simplifies the structure of the lubrication system 50, avoids the oil circuit confusion and sealing problems that may be caused by the traditional multiple independent lubrication inlets, and improves the overall reliability and stability of the device. In addition, stable lubrication can ensure the smoothness of the differential pressure piston 12, the first piston rod 13, and the second piston rod 18 during the sliding process, reduce the interference of the friction resistance fluctuation on the detection results, thereby greatly improving the measurement accuracy and sensitivity of the differential pressure detection device 10 and meeting the needs of high-precision detection.

[0071] like Figures 2 to 7As shown, another embodiment of the present invention provides a differential pressure detection device 10, the pressure cylinder 11 includes a cylinder barrel 110, an upper cylinder cover 116 and a lower cylinder cover 117, the upper cylinder cover 116 and the lower cylinder cover 117 are coaxially arranged at the upper and lower ends of the cylinder barrel 110; a second oil hole and a second oil channel 194 are provided in the upper cylinder cover 116, and a third oil hole and a third oil channel 197 are provided in the lower cylinder cover 117; a first sliding hole is provided at the center of the upper cylinder cover 116, and a second sliding hole is provided at the center of the lower cylinder cover 117, and sliding sealing gaskets 118 are provided in the first sliding hole and the second sliding hole, the first sliding hole is slidably sealed with the first piston rod 13 through the sliding sealing gasket 118, and the second sliding hole is slidably sealed with the second piston rod 18 through the sliding sealing gasket 118; a limiting boss is provided on the outer periphery of the sliding sealing gasket 118, and the limiting boss is snap-fitted with the annular groove on the inner wall of the upper cylinder cover 116 or the lower cylinder cover 117.

[0072] The pressure cylinder 11 adopts a split structural design, consisting of three parts: a cylinder barrel 110, an upper cylinder head 116, and a lower cylinder head 117. The upper cylinder head 116 and the lower cylinder head 117 are coaxially mounted at the upper and lower ends of the cylinder barrel 110 via threaded connections, forming a complete pressure-sealed chamber. A second oil hole is radially defined within the upper cylinder head 116. One end of this second oil hole is connected to the first lubricating oil interface 115, and the other end is connected to an annular second oil passage 194 circumferentially defined along the inner wall of the upper cylinder head 116. Similarly, a third oil hole and an annular third oil passage 197 are provided within the lower cylinder head 117, and their connection method is similar to that of the upper cylinder head 116, ensuring that the lubricating medium can be transported from the first lubricating oil interface 115 to the sliding sealing area of ​​the upper and lower cylinder heads 116, 117.

[0073] A first sliding hole is provided at the center of the upper cylinder head 116, and a second sliding hole is provided at the lower cylinder head 117. The inner diameter of the first sliding hole is slightly larger than the outer diameter of the first piston rod 13. The first sliding hole and the first piston rod 13 form an annular gap for mounting a sliding seal 118. A limiting boss is provided on the outer circumferential surface of the sliding seal 118. The outer diameter of the limiting boss engages with the annular groove on the inner wall of the upper cylinder head 116 to achieve axial limitation of the sliding seal 118. A plurality of guide holes are provided along the circumference of the sliding seal 118. The ends of the guide holes respectively penetrate the inner and outer surfaces of the sliding seal 118. The guide holes are used to guide the lubricating oil stored in the second oil passage 194 in the upper cylinder head 116 to the inner surface of the sliding seal 118. This allows the lubricating medium to form a continuous lubricating film on the sliding surfaces of the first piston rod 13 and the sliding seal 118 when the first piston rod 13 moves up and down.

[0074] Similarly, the inner diameter of the second sliding hole is slightly larger than the outer diameter of the second piston rod 18. The second sliding hole and the second piston rod 18 form an annular gap for mounting a sliding seal 118. A limiting boss is provided on the outer circumferential surface of the sliding seal 118. The outer diameter of the limiting boss engages with an annular groove on the inner wall of the lower cylinder head 117, thereby limiting the axial position of the sliding seal 118. A plurality of guide holes are provided along the circumference of the sliding seal 118. The ends of the guide holes penetrate the inner and outer surfaces of the sliding seal 118, respectively. The guide holes are used to direct the lubricating oil stored in the third oil passage 197 in the lower cylinder head 117 to the inner surface of the sliding seal 118. This allows the lubricating medium to form a continuous lubricating film on the sliding surfaces of the second piston rod 18 and the sliding seal 118 as the second piston rod 18 moves up and down.

[0075] This split-type pressure cylinder 11 structure and sliding seal design offer numerous technical advantages. First, the independent design of the upper and lower cylinder covers 116 and 117 facilitates processing and assembly, allowing for the selection of differentiated materials and processing techniques to meet varying sealing requirements, thereby improving sealing performance and service life. Second, the sliding seal 118, through the snap-fitting engagement between the retaining boss and the annular groove, effectively prevents displacement or flipping of the seal during the reciprocating motion of the piston rod, ensuring a reliable and stable seal.

[0076] like Figures 2 to 7 As shown, another embodiment of the present invention provides a differential pressure detection device, wherein the first lubricating oil interface 115 is connected to the first oil hole and the first oil channel 192, the second oil hole and the second oil channel 194, and the third oil hole and the third oil channel 197 through the branch oil channel system 19; the branch oil channel system 19 includes a first branch oil channel 191, a second branch oil channel 193 and a third branch oil channel 195; the first branch oil channel 191 is horizontally arranged, one end of which extends toward the side wall of the sliding cavity and is connected to the first oil channel 192 through the first oil hole; the second branch oil channel 193 is an L-shaped structure. The structure has a vertical section extending upward from the first branch oil circuit 191 into the upper cylinder head 116, and the horizontal section of the first branch oil circuit 191 extends toward the through hole and is connected to the second oil channel 194 through the second oil hole; the third branch oil circuit 195 is vertically arranged, extending from the first branch oil circuit 191 toward the lower cylinder head 117, and passes through the lower cylinder head 117 to connect to the external lubrication system 50; the fourth branch oil circuit 196 is horizontally arranged in the lower cylinder head 117, one end of which is connected to the third branch oil circuit 195, and the other end is connected to the third oil channel 197 through the third oil hole.

[0077] The first lubricating oil interface 115 serves as the main inlet of the lubricating medium, and accurately supplies oil to different sliding surfaces through the branch oil circuit system 19. The branch oil circuit system 19 is composed of a first branch oil circuit 191, a second branch oil circuit 193, a third branch oil circuit 195, and a fourth branch oil circuit 196.

[0078] First branch oil passage 191 is arranged horizontally, with one end extending toward the sidewall of the sliding cavity of pressure cylinder 11. First branch oil passage 191 communicates with first oil passage 192, which surrounds the center of the sliding cavity, via a first oil hole, ensuring that lubricating medium is promptly delivered to the contact surface between differential pressure piston 12 and the inner wall of pressure cylinder 11.

[0079] The second branch oil passage 193 has an L-shaped structure, with its vertical section extending upward from the first branch oil passage 191, passing through the cylinder barrel 110 of the pressure cylinder 11, and ending in the interior of the upper cylinder head 116. After entering the upper cylinder head 116, the horizontal section of the second branch oil passage 193 extends toward a through-hole housing a sliding seal 118 that provides a sliding seal with the first piston rod 13. The second branch oil passage 193 communicates via a second oil hole with a second oil passage 194 circumferentially extending along the inner wall of the upper cylinder head 116, allowing the lubricant to effectively lubricate the sliding seal between the first piston rod 13 and the upper cylinder head 116.

[0080] A third branch oil passage 195 extends vertically downward from the first branch oil passage 191 toward the lower cylinder head 117, penetrating the latter. The distal end of the third branch oil passage 195 is connected to an external lubricating medium supply device via the first lubricating oil port 115. Furthermore, a horizontally extending fourth branch oil passage 196 is disposed within the lower cylinder head 117. One end of the fourth branch oil passage 196 communicates with the third branch oil passage 195, while the other end communicates via a third oil hole with a third oil passage 197 circumferentially disposed along the inner wall of the lower cylinder head 117, thereby delivering lubricating medium to the sliding contact area between the second piston rod 18 and the lower cylinder head 117.

[0081] By utilizing branch oil circuits with varying structures and orientations, precise distribution and efficient delivery of lubricating medium can be achieved, tailored to the operating characteristics and lubrication requirements of differential pressure piston 12, first piston rod 13, and second piston rod 18. Furthermore, a rational oil circuit layout and sealing structure design ensure the stability and sealing of the lubricating medium during delivery, reducing component wear caused by lubricating medium leakage or insufficient supply, extending the service life of differential pressure detection device 10, and ensuring both operational reliability and the accuracy of detection results.

[0082] like Figures 4 to 8 As shown, another embodiment of the present invention provides a differential pressure detection device, the differential pressure detection device 10 also includes a drainage mechanism 60, the drainage mechanism 60 includes a drainage elastic tube 61, a drainage external tube 62 and a seventh control valve 63, a drainage hole is provided on the lower cylinder cover 117 at one end close to the second chamber 112, and an avoidance hole connected to the drainage hole is provided below the drainage hole, the lower end of the avoidance hole passes through the bottom of the lower cylinder cover 117, and the diameter of the avoidance hole is larger than the diameter of the drainage hole.

[0083] The drain elastic tube 61 is located in the avoidance hole, and one end is connected to the drain hole, the drain outer tube 62 is connected to the other end of the drain elastic tube 61, and the seventh control valve 63 is arranged on the drain outer tube 62; wherein, the drain elastic tube 61 is an N-shaped bending structure, and a thin-walled section 64 is provided at the part close to the second chamber 112, so that it can expand under the action of pressure and squeeze the part away from the second chamber 112 on the side wall of the avoidance hole for sealing.

[0084] Furthermore, the drain mechanism 60 includes a drain elastic tube 61, a drain external tube 62, and a seventh control valve 63. A drain hole and a relief hole are vertically arranged on the lower cylinder cover 117. The relief hole has a larger diameter than the drain hole to facilitate installation of the drain elastic tube 61. The drain hole communicates with the bottom of the second chamber 112, while the lower end of the relief hole penetrates the lower cylinder cover 117 and communicates with the atmosphere.

[0085] The drain elastic tube 61 is an N-shaped bent structure, with one end sealed to the drain hole and the other end extending through the relief hole to connect to the drain outer tube 62. A seventh control valve 63 is mounted on the drain outer tube 62 to control the flow of oil. A thin-walled section 64 is provided near the first cavity 103 of the drain elastic tube 61.

[0086] When the system is in operation, the internal pressure of the cylinder 110 increases, and the thin-walled section 64 expands outward under the action of pressure, pushing the distal end of the drain elastic tube 61 to fit tightly against the side wall of the avoidance hole, forming a dynamic seal to prevent the lubricating medium from leaking; when the system stops working or the internal pressure increases abnormally, the internal pressure of the cylinder 110 decreases or exceeds the limit, the thin-walled section 64 retracts, and the drain elastic tube 61 returns to its bent state, and the lubricating medium is discharged through the drain outer tube 62 and the seventh control valve 63, thereby achieving pressure relief and discharge.

[0087] A second embodiment of the present invention provides a multi-parameter transmitter detection device, including the above-mentioned differential pressure detection device 10, a static pressure module 20 and a pressure delivery system 30; the static pressure module 20 is used to generate static pressure or gauge pressure; the pressure delivery system 30 is connected to the differential pressure detection device 10 and the static pressure module 20 respectively, and is provided with an interface component for connecting to the multi-parameter transmitter 40 to be measured, for delivering pressure through a gas medium.

[0088] like Figure 1 As shown, when the pressure detection device of the present invention is working, the differential pressure detection device 10 is used to detect the differential pressure of the order of 0.1kPa-400kPa; the static pressure module 20 is used to generate the static pressure or gauge pressure of the order of 0.1MPa-100MPa; the specific working process is as follows:

[0089] The multi-parameter transmitter 40 to be measured is connected to the pressure delivery system 30 via the interface assembly. To test differential pressure, the load assembly 17 is operated. This changes the position of the first piston rod 13, causing the differential pressure piston 12 to displace within the first chamber, thereby changing the pressure within the first chamber 111 or the second chamber 112. The relevant pipeline valves of the pressure delivery system 30 are then opened, allowing the gaseous medium to enter the first chamber 111 or the second chamber 112, creating a differential pressure on the order of 0.1 kPa to 400 kPa.

[0090] When performing static or gauge pressure testing, some pipeline valves are closed and the valve associated with the static pressure module 20 is opened. The static pressure module 20 generates static or gauge pressures ranging from 0.1 MPa to 100 MPa, which are transmitted to the testing location via the pressure delivery system 30. If system pressure adjustment is required, the pressure delivery system 30 can be connected via corresponding pipelines to replenish or release the gas medium. During the pressure testing process, if pressure balance is required across the differential pressure piston 12, specific pipeline connecting valves can be opened to achieve pressure balance.

[0091] Compared with the existing technology, this pressure detection equipment organically combines the function of the differential pressure piston 12 to accurately detect the differential pressure performance of the multi-parameter transmitter 40 under test with the ability of the general piston to meet multiple measurement requirements such as absolute pressure and gauge pressure through the integrated design of the differential pressure detection device 10 and the static pressure module 20. While optimizing the overall structure, it effectively reduces the volume of the device, shortens the pressure transmission path, and reduces the error in the pressure transmission process. The differential pressure detection device 10 in the present invention can efficiently and accurately complete the detection work of the multi-parameter transmitter under different pressure parameters, greatly improving the detection efficiency and reliability, and can meet diverse and high-precision detection needs.

[0092] A second embodiment of the present invention provides a multi-parameter transmitter detection device, the pressure delivery system 30 includes: an air source component 31, a first air path 32, a second air path 34, a third air path 33, a fourth air path 35, a fifth air path 36, a sixth air path 38 and a one-way fluid buffer 37; the air source component 31 is connected to the static pressure module 20 for supplying a gas medium; the first air path 32 is respectively connected to the first communication interface 113 and the negative pressure port of the interface component, and a first control valve 321 is provided on the first air path 32 for controlling the on-off of the gas medium in the first air path 32 to adjust the gas pressure in the first chamber 111 and the gas pressure entering the multi-parameter transmitter 40 to be measured; the third air path 33 is respectively connected to the second communication interface 114 and the static pressure module 20, and a third control valve 331 is provided on the end of the third air path 33 close to the differential pressure piston 12 for controlling the fluid communication between the second chamber 112 and the static pressure module 20, and the third air path 33 is close to the static pressure module 20. A sixth control valve 332 is provided at one end of the gas circuit 33 for adjusting the gas pressure outputted from the static pressure module 20 to the third gas circuit 33; the second gas circuit 34 is connected to the first gas circuit 32 and the third gas circuit 33 respectively, and is provided with a second control valve 341 thereon for controlling the fluid communication between the first gas circuit 32 and the third gas circuit 33 to balance the pressure difference between the first chamber 111 and the second chamber 112; the fourth gas circuit 35 is connected to the third gas circuit 33 and the outlet end of the gas source assembly 31 respectively, and is provided with a fifth control valve 351 thereon for controlling the fluid communication between the gas source assembly 31 and the third gas circuit 33 to replenish or release the gas medium; the fifth gas circuit 36 ​​is connected to the third gas circuit 33 and the positive pressure port of the interface assembly respectively, and is used to output the gas medium in the measured multi-parameter transmitter 40; the one-way fluid buffer 37 is used to provide pressure compensation; the sixth gas circuit 38 is connected to the one-way fluid buffer 37 and the first gas circuit 32 respectively, and is provided with a fourth control valve 381 thereon.

[0093] like Figures 1 to 7 As shown, when the pressure delivery system 30 of the present invention is in operation, the various components work together to achieve precise control and pressure regulation of a gas medium (e.g., nitrogen). The specific process is as follows: Before measurement begins, the operator preloads the differential pressure detection device 10 by operating the load assembly 17 according to the expected detection pressure range. The force of the load assembly 17 is transmitted to the differential pressure piston 12 via the first piston rod 13, driving the differential pressure piston 12 to move within the sliding cavity, forming an initial mechanical pressure reference, providing a reference for subsequent differential pressure measurements. Simultaneously, the gas source assembly 31 pre-stores a sufficient amount of gas medium and, through its connection to the static pressure module 20, provides a stable pressure source reserve for the system.

[0094] The static pressure generation process is as follows. First, the air source assembly 31 acts as the pressure source for the stored fluid medium, providing an initial pressure input to the static pressure module 20 via the third air path 33. The sixth control valve 332 initially regulates the pressure of the gas entering the static pressure module 20, controlling the pressure level. Second, the static pressure module 20 is equipped with weights of varying specifications. By loading the weights onto the static pressure piston, the weights' gravity is combined with the gas pressure provided by the air source assembly 31. For example, increasing the number of weights increases the total pressure, while decreasing it decreases. Finally, a pressure regulator is positioned between the air source assembly 31 and the static pressure module 20. This regulator is a piston with a screw. Rotating the screw moves the piston within the chamber, changing the volume of gas within it. Based on the principle of gas state, changes in volume cause changes in pressure, which in turn fine-tunes the pressure of the gas flowing to the static pressure module 20. This allows the static pressure module 20 to generate high-precision static pressure values, which are used to test the static pressure measurement performance of the multi-parameter transmitter 40 under test. Evaluate the accuracy of the device under test by comparing its output value with the actual static pressure value.

[0095] When it is necessary to perform differential pressure detection on the multi-parameter transmitter 40 under test, the static pressure module 20 is first started to a stable working state, and the first control valve 321, the second control valve 341, the third control valve 331, and the fourth control valve 381 are opened to ensure that the pipelines of the pressure delivery system 30 are connected and the fluid medium flows normally. Secondly, the second control valve 341 is closed to cut off the pressure balance between the first chamber 111 and the second chamber 112; the fourth control valve 381 set on the sixth gas path 38 is opened. The fourth control valve 381 is used to control the flow of gas medium into and out of the one-way fluid buffer 37 and adjust the pressure output of the one-way fluid buffer 37; by adjusting the one-way fluid buffer 37, the pressure on the negative pressure side of the multi-parameter transmitter 40 under test is changed, so that a pressure difference is generated at both ends of the differential pressure piston 12; for example, when the pressure on the negative pressure side is increased, the differential pressure piston 12 moves to one side; otherwise, it moves in the opposite direction; again, the differential pressure piston 12 drives the first piston rod 13 to move under the action of the pressure difference. The operator precisely controls the pressures in first and second chambers 111, 112 by adjusting first, third, sixth, and fifth control valves 321, 331, 332, and 351, aligning the pointers with the corresponding scales on the sidewalls of flywheel 14 and maintaining their operating height. Finally, a stable pressure differential is transmitted through the positive and negative pressure ports of the multi-parameter transmitter 40 under test. Static pressure is measured on the positive pressure side, and the differential pressure is used for flow detection. Measurement accuracy is assessed by comparing the output value of the device under test with the actual differential pressure value.

[0096] It can be seen that the first control valve 321 to the sixth control valve 332 are combined to form a control valve group, which has four functions: first, in the initial balancing stage, the second control valve 341 is opened to connect the first chamber 111 and the second chamber 112 through the second air path 34 to quickly balance the pressure difference; second, in the differential pressure detection stage, the second control valve 341 is closed to isolate the two chambers; the one-way fluid buffer 37 is adjusted to control the pressure on the negative pressure side, and the pressure of the second chamber 112 is adjusted through the third control valve 331 and the sixth control valve 332; third, in the pressure compensation stage: when the system pressure fluctuates, the fourth control valve 381 is opened, and the one-way fluid buffer 37 absorbs or releases the gas medium through the sixth air path 38 to achieve dynamic pressure compensation; fourth, in the medium recovery stage: after the detection is completed, the fifth air path 36 is opened to discharge the gas medium in the multi-parameter transmitter through the interface component to complete the medium recovery.

[0097] Through the orderly coordination of various air pressure pipelines and control valve groups, the pressure delivery system 30 realizes comprehensive control over the on-off, flow direction and pressure of the gas medium, providing a stable and accurate pressure environment for the detection of multi-parameter transmitters.

[0098] like Figures 1 to 7 As shown, a multi-parameter transmitter detection device provided by the second embodiment of the present invention also includes a lubrication system 50, which provides lubricating medium for the differential pressure detection device 10 and the static pressure module 20. The lubrication system 50 includes an oil cup 51, a first oil circuit 52, a second oil circuit 53 and an air pressure balance pipeline 54; the oil cup 51 is used to store lubricating medium; one end of the first oil circuit 52 is connected to the oil cup 51 and is connected to the first lubricating oil interface 115 of the differential pressure detection device 10; the sliding surface of the differential pressure piston 12 and the inner wall of the pressure cylinder 11; the sliding surface of the first piston rod 13 and the upper cylinder cover 116; the sliding surface of the second piston rod 18 and the lower cylinder cover 117; one end of the second oil circuit 53 is connected to the oil cup 51, and the other end is connected to the static pressure module 20, for providing lubricating medium for the static pressure module 20; the air pressure balance pipeline 54 is respectively connected to the upper part of the oil cup 51 and the pressure delivery system 30, for balancing the pressure between the inside of the lubrication system 50 and the pressure delivery system 30.

[0099] A suitable lubricating medium is injected into the lubrication system 50 and transported through the oil pipeline to the lubrication points of the differential pressure detection device 10 and the static pressure module 20 to ensure that all components are well lubricated. The lubrication system 50 achieves efficient lubrication and reliable sealing of the core components of the pressure detection equipment through a reasonable structural design and gas medium transmission mechanism. The specific working process is as follows:

[0100] The lubrication system 50 is designed to supply lubricating medium to the differential pressure detection device 10 and the static pressure module 20. Its core components include an oil cup 51, a first oil circuit 52, and a second oil circuit 53. A certain gap is reserved above the liquid level in the oil cup 51. This design takes into account the lubricating medium's thermal expansion and contraction characteristics. Heat generated during equipment operation causes the lubricating medium to heat up and expand. If the oil cup 51 is completely filled, the internal pressure will rise sharply, potentially causing the oil cup 51 seal to fail, oil leakage, and even more serious safety hazards. The reserved gap provides a buffer for the oil expansion, ensuring the stable and safe operation of the lubrication system 50.

[0101] One end of the first oil passage 52 is connected to the bottom of the oil cup 51, and the other end of the first oil passage 52 is connected to the first lubricating oil port 115 of the differential pressure detection device 10, for supplying lubricating medium to the following lubricating surfaces: the sliding surface between the differential pressure piston 12 and the inner wall of the pressure cylinder 11, the sliding surface between the first piston rod 13 and the sliding seal 118, and the sliding surface between the second piston rod 18 and the sliding seal 118;

[0102] The inner wall of the pressure cylinder 11 is laser-engraved with a 2-micron-deep lattice structure. These tiny pits store lubricant. When the differential pressure piston 12 moves, lubricant is drawn into the pressure cylinder 11, with some retained in the lattice spaces. This structure subsequently replenishes lubrication between the differential pressure piston 12 and the inner wall of the pressure cylinder 11, effectively reducing friction. Alternatively, the lattice structure could be replaced with grooves in a specific pattern; both achieve the same functions of lubricant storage and friction reduction.

[0103] The second oil circuit 53 is responsible for providing lubrication for the hydrostatic module 20. One end of the second oil circuit 53 is connected to the bottom of the oil cup 51 via a tee, and the other end is connected to the internal oil circuit of the hydrostatic module 20. The hydrostatic module 20 includes a hydrostatic piston and a hydrostatic cylinder. During the reciprocating motion of the hydrostatic piston, the second oil circuit 53 continuously supplies lubricating medium to the hydrostatic module 20, forming an effective lubricating film in the sliding engagement area between the hydrostatic piston and the inner wall of the hydrostatic cylinder, reducing component wear and ensuring the operational accuracy and reliability of the hydrostatic module 20.

[0104] The pneumatic balancing line 54 is connected to the top of the oil cup 51 and the pressure delivery system 30, respectively. Its function is to balance the pressure between the lubrication system 50 and the pressure delivery system 30. When the pressure in the pressure delivery system 30 increases, the pressure sensor in the pneumatic balancing line 54 detects the pressure change and controls the valve to open, introducing some of the gas from the pressure delivery system 30 into the space above the oil cup 51. This balances the pressure in the lubrication system 50 and the pressure delivery system 30, preventing the lubricating medium from leaking through the oil pipeline or seals due to pressure differentials. When the pressure in the pressure delivery system 30 decreases, the pneumatic balancing line 54 discharges excess gas from the oil cup 51 into the pressure delivery system 30, maintaining stable system pressure. Furthermore, the pneumatic balancing line 54 prevents the lubricating medium in the oil cup 51 from escaping or being drawn into the pressure delivery system 30 due to pressure fluctuations, ensuring the stable operation of both the lubrication system 50 and the pressure delivery system 30.

[0105] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are intended to be construed as follows.

Claims

1. A differential pressure detection device, characterized in that: include: A pressure cylinder (11) is provided with a sliding cavity therein, and the pressure cylinder (11) is also provided with a first communication interface (113), a second communication interface (114) and a first lubricating oil interface (115); a differential pressure piston (12) slidably disposed in the sliding cavity and sealingly engaged with the inner wall of the pressure cylinder (11) to separate the sliding cavity into a first chamber (111) and a second chamber (112); the first communication interface (113) is in communication with the first chamber (111), the second communication interface (114) is in communication with the second chamber (112), and the first lubricating oil interface (115) is in communication with the middle of the sliding cavity; A first piston rod (13), one end of which is connected to the differential pressure piston (12), and the other end of which passes through the pressure cylinder (11) and is in sliding and sealing engagement with the pressure cylinder (11); a flywheel (14) rotatably mounted on the pressure cylinder (11) and sleeved on the first piston rod (13); A stopper (15) fixedly disposed on the flywheel (14); a shifter (16) fixedly mounted on the first piston rod (13) and intersecting the stopper (15) at a spatial angle, for contacting the stopper (15) when the flywheel (14) rotates and having a sliding degree of freedom to drive the first piston rod (13) to rotate; A driving mechanism (140) is connected to the flywheel (14) in a transmission manner to impart an initial speed of rotation to the flywheel (14); A load assembly (17) is provided on the first piston rod (13) and is used to apply an axial load to the first piston rod (13).

2. The differential pressure detection device according to claim 1, wherein: The driving mechanism (140) comprises: A guide rail (141) is used for being fixedly arranged relative to the pressure cylinder (11); A cylinder (142) is provided on the guide rail (141); a rack (143) slidably disposed on the guide rail (141) and connected to the cylinder (142) so as to slide on the guide rail (141) driven by the cylinder (142); a ring gear (144) disposed on the flywheel (14) and meshing with the rack (143); Wherein, the rack (143) is separated from the gear ring (144) after moving to a preset position.

3. The differential pressure detection device according to claim 1, wherein: The flywheel (14) is a cylindrical structure. The blocking member (15) includes a blocking plate (151) vertically arranged at the bottom of the flywheel (14). The shifting member (16) includes a shifting rod (161) vertically arranged on the first piston rod (13). A pulley (162) is provided on the shifting rod (161) at a portion for contacting the blocking plate (151).

4. The differential pressure detection device according to claim 3, wherein: The pressure cylinder (11) is arranged vertically, and the axial length of the differential pressure piston (12) does not exceed half of the stroke of the differential pressure piston (12) in the sliding cavity; The upper surface of the differential pressure piston (12) is connected to the lower end of the first piston rod (13), and the lower surface of the differential pressure piston (12) is provided with a second piston rod (18), and the lower end of the second piston rod (18) passes through the pressure cylinder (11) and is in sliding sealing cooperation with the pressure cylinder (11); The load assembly (17) comprises: a ballast tray (171), disposed above the pressure cylinder (11) and connected to the upper end of the first piston rod (13), for placing a calibration object (172); A mounting tray (173) is provided below the pressure cylinder (11) and is connected to the lower end of the second piston rod (18) for mounting a calibration object (172).

5. The differential pressure detection device according to claim 4, wherein: A first oil hole and a first oil channel (192) corresponding to the sliding surface of the differential pressure piston (12) are provided in the middle of the pressure cylinder (11); a second oil hole and a second oil channel (194) corresponding to the sliding surface of the first piston rod (13) are provided at the upper end of the pressure cylinder (11); a third oil hole and a third oil channel (197) corresponding to the sliding surface of the second piston rod (18) are provided at the lower end of the pressure cylinder (11); the first oil hole and the first oil channel (192), the second oil hole and the second oil channel (194), and the third oil hole and the third oil channel (197) are all connected to the first lubricating oil interface (115).

6. The differential pressure detection device according to claim 5, wherein: The pressure cylinder (11) comprises a cylinder barrel (110), an upper cylinder cover (116) and a lower cylinder cover (117), wherein the upper cylinder cover (116) and the lower cylinder cover (117) are coaxially arranged at the upper and lower ends of the cylinder barrel (110); The second oil hole and the second oil passage (194) are provided in the upper cylinder head (116), and the third oil hole and the third oil passage (197) are provided in the lower cylinder head (117); A first sliding hole is provided at the center of the upper cylinder cover (116), and a second sliding hole is provided at the center of the lower cylinder cover (117). Sliding sealing gaskets (118) are provided in both the first sliding hole and the second sliding hole. The first sliding hole is slidably sealed with the first piston rod (13) through the sliding sealing gasket (118), and the second sliding hole is slidably sealed with the second piston rod (18) through the sliding sealing gasket (118). A limiting boss is provided on the outer periphery of the sliding sealing gasket (118), and the limiting boss is engaged with an annular groove on the inner wall of the upper cylinder cover (116) or the lower cylinder cover (117).

7. The differential pressure detection device according to claim 6, wherein: The differential pressure detection device (10) further includes a drainage mechanism (60), the drainage mechanism (60) including a drainage elastic tube (61), a drainage external tube (62) and a seventh control valve (63), a drainage hole is provided on one end of the lower cylinder cover (117) close to the second chamber (112), a relief hole is provided below the drainage hole and is in communication with the drainage hole, the lower end of the relief hole passes through the bottom of the lower cylinder cover (117), and the diameter of the relief hole is larger than the diameter of the drainage hole; the drainage elastic tube (61) is provided with a drainage hole, and the drainage hole is provided with a drainage hole. 1) Located in the avoidance hole, and one end is sealedly connected to the drain hole, the drain outer tube (62) is connected to the other end of the drain elastic tube (61), and the seventh control valve (63) is arranged on the drain outer tube (62); wherein the drain elastic tube (61) is an N-shaped bending structure, and a thin-walled section (64) is provided at a portion close to the second chamber (112) so as to expand under pressure and squeeze the portion away from the second chamber (112) onto the side wall of the avoidance hole for sealing.

8. A multi-parameter transmitter detection device, characterized in that: include: The differential pressure detection device (10) according to any one of claims 1 to 7; A static pressure module (20) for generating static pressure or gauge pressure; The pressure delivery system (30) is connected to the differential pressure detection device (10) and the static pressure module (20) respectively, and is provided with an interface component for connecting to a measured multi-parameter transmitter (40) for delivering pressure through a gas medium.

9. The multi-parameter transmitter detection device according to claim 8, characterized in that: The pressure delivery system (30) comprises: A gas source assembly (31), connected to the static pressure module (20), for supplying a gas medium; a first gas circuit (32) connected to the first communication interface (113) and the negative pressure port of the interface assembly, respectively; a first control valve (321) is provided on the first gas circuit (32) for controlling the on-off of the gas medium in the first gas circuit (32) to adjust the gas pressure in the first chamber (111) and the gas pressure entering the measured multi-parameter transmitter (40); a third gas circuit (33) connected to the second communication interface (114) and the static pressure module (20), respectively; a third control valve (331) is provided on one end of the third gas circuit (33) close to the differential pressure piston (12) for controlling fluid communication between the second chamber (112) and the static pressure module (20); and a sixth control valve (332) is provided on one end of the third gas circuit (33) close to the static pressure module (20) for adjusting the gas pressure output from the static pressure module (20) to the third gas circuit (33); a second gas path (34), connected to the first gas path (32) and the third gas path (33), respectively, and provided with a second control valve (341) for controlling fluid communication between the first gas path (32) and the third gas path (33) to balance the pressure difference between the first chamber (111) and the second chamber (112); a fourth gas path (35) connected to the third gas path (33) and the outlet end of the gas source component (31), respectively, and provided with a fifth control valve (351) for controlling the fluid communication between the gas source component (31) and the third gas path (33) to replenish or release the gas medium; a fifth gas path (36), connected to the third gas path (33) and the positive pressure port of the interface assembly, respectively, for outputting the gas medium in the measured multi-parameter transmitter (40); A one-way fluid buffer (37) for providing pressure compensation; The sixth gas path (38) is connected to the one-way fluid buffer (37) and the first gas path (32) respectively, and is provided with a fourth control valve (381).

10. The multi-parameter transmitter detection device according to claim 8, characterized in that: The multi-parameter transmitter detection device further includes a lubrication system (50), wherein the lubrication system (50) provides lubrication medium for the differential pressure detection device (10) and the static pressure module (20), and the lubrication system (50) includes: An oil cup (51) for storing lubricating medium; A first oil circuit (52), one end of which is connected to the oil cup (51), and the other end of which is connected to the first lubricating oil interface (115) of the differential pressure detection device (10); A second oil circuit (53), one end of which is connected to the oil cup (51) and the other end of which is connected to the static pressure module (20), and is used to provide lubricating medium to the static pressure module (20); The air pressure balancing pipeline (54) is respectively connected to the upper part of the oil cup (51) and the pressure delivery system (30), and is used to balance the pressure between the inside of the lubrication system (50) and the pressure delivery system (30).

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