Differential pressure detection device and multi-parameter transmitter detection equipment

Abstract

The invention provides a differential pressure detection device and multi-parameter transmitter detection equipment, and belongs to the technical field of pressure measurement, and the differential pressure detection device comprises a pressure cylinder, a differential pressure piston, a first piston rod, a flywheel, a blocking piece, a shifting piece, a driving mechanism and a load assembly. The multi-parameter transmitter detection equipment comprises the differential pressure detection device, a static pressure module and a pressure conveying system. According to the invention, the precision of differential pressure detection can be improved, and particularly, a multi-parameter transmitter can be better detected.

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 device. Background Art

[0002] The multi-parameter transmitter is a sensing device widely used in industrial fields such as chemical industry, energy, pharmaceutical, and food. It adopts a composite sensing technology and can simultaneously measure three different process parameters: differential pressure, static pressure, and temperature. This reduces the volume and structural complexity of the measurement system, increases reliability, and reduces the manufacturing cost by 30% - 40%. Through the embedded flow calculation, correction, and integration module, it internally compensates for differential pressure, static pressure, and temperature, improving the accuracy of the measurement results of the mass and volume flow of the measured medium. The modular structure supports various process connections and multiple communication protocols. Before use, the multi-parameter transmitter needs to be detected and calibrated to determine whether its detection 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. In actual detection work, the actual working state of such transmitters cannot be reproduced, that is, both the working pressure value within the given design range and the multi-point differential pressure values within the design range are given. When detecting the measurement accuracy of the pressure channel, the measurement accuracy of the differential pressure and flow channels cannot be detected. Only by changing the temperature and pressure input signals to a fixed mode through configuration software, the measurement performance of the differential pressure and flow channels can be detected without static pressure and temperature signals, which cannot correctly and comprehensively reflect the technical parameter indicators of the entire multi-parameter transmitter.

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

[0004] Currently, the main method that can relatively accurately detect differential pressure is to use a piston-type pressure gauge. The piston is located in the pressure cylinder and divides the pressure cylinder into upper and lower spaces. The two spaces are respectively connected to the gas interfaces on both sides of the device to be detected through pipelines. The piston moves in the pressure cylinder under the action of differential pressure, and the specific value is transmitted through a connecting rod that penetrates the pressure cylinder and is connected to the piston in the form of force and displacement. However, the friction between the piston and the piston rod and the pressure cylinder will affect the detection accuracy, and even by applying lubricating oil to the inner wall of the pressure cylinder, it is difficult to achieve good improvement.

[0005] To solve the above problems, we designed a differential pressure detection device and a multi-parameter transmitter detection device 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 requirements of high-precision pressure and differential pressure detection.

[0007] To achieve the above object, 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 dialing member, a driving mechanism and a load assembly; a sliding cavity is provided inside the pressure cylinder, and the pressure cylinder is further provided with a first communication interface, a second communication interface and a first lubricating oil interface; the differential pressure piston is slidably arranged in the sliding cavity and is hermetically fitted with the inner wall of the pressure cylinder to divide the sliding cavity into a first chamber and a second chamber, the first communication interface is communicated with the first chamber, the second communication interface is communicated with the second chamber, and the first lubricating oil interface is communicated with 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 slidably and hermetically fitted with the pressure cylinder; the flywheel is rotatably arranged on the pressure cylinder and sleeved on the first piston rod; the stopper is fixedly arranged on the flywheel; the dialing member is fixedly arranged on the first piston rod and is in a crossed state with a spatial angle with the stopper, and is used to abut against the stopper and have a sliding freedom when the flywheel rotates to drive the first piston rod to rotate; the driving mechanism is in transmission connection with the flywheel to give the flywheel an initial rotational speed; 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 relatively fixedly arranged with the pressure cylinder; the cylinder is arranged on the guide rail; the rack is slidably arranged on the guide rail and is connected with the cylinder to slide on the guide rail under the drive of the cylinder; the gear ring is arranged on the flywheel and meshes with the rack; wherein, after the rack moves to a preset position, it is separated from the gear ring.

[0008] The beneficial effect of the differential pressure detection device provided by the present invention is that: compared with the existing technology, the present invention gives the flywheel an initial rotational speed through the driving mechanism, and when the flywheel rotates, due to the limiting effect between the stopper and the dialing member, the flywheel continues to drive the first piston rod and the differential pressure piston to rotate, so that a relative rotation is generated between the first piston rod and the differential pressure piston and the pressure cylinder, so that the lubricating oil entering from the first lubricating oil interface can be evenly distributed between the first piston rod and the differential pressure piston and the pressure cylinder to reduce friction, and at the same time, the first piston rod and the differential pressure piston and the pressure cylinder always remain in a dynamic friction state, improving the sensitivity of the piston movement; then as the rotational speed of the flywheel gradually decreases, the power transmission between the stopper and the dialing member disappears, eliminating the influence of the friction between the stopper and the dialing member on the movement of the differential pressure piston. At this time, the differential pressure piston is neither affected by the starting friction nor affected by other external frictions, and its accuracy is in a relatively high state. And the differential pressure can be calculated through the loading amount of the load assembly and the sliding distance of the differential pressure piston. In this way, more accurate detection of the differential pressure can be achieved, and more accurate differential pressure detection data can be obtained.

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

[0010] The beneficial effect of the multi-parameter transmitter detection device provided by the present invention lies in: compared with the prior art, through the integrated design of the differential pressure detection device and the static pressure module, the present invention organically combines the function of accurately detecting the differential pressure performance of the multi-parameter transmitter to be measured by the differential pressure piston with the ability of the universal piston to meet the multi-dimensional measurement requirements such as absolute pressure and gauge pressure. While optimizing the overall structure, it effectively reduces the volume of the device, shortens the pressure transmission path, reduces the error in the pressure transmission process, enables the differential pressure detection device in the present invention to efficiently and accurately complete the detection work of the multi-parameter transmitter under different pressure parameters, greatly improves the detection efficiency and reliability, and can meet the diversified and high-precision detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0012] Figure 1 It is a schematic diagram of the positional structure of the differential pressure detection device provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the positional structure of the load component, the stopper, the flywheel, the shifting member, and the pressure cylinder provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the positional structure of the driving mechanism and the flywheel provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the structure of the branch oil circuit system provided by another embodiment of the present invention; Figure 5 It is a schematic diagram of the positional structure of the upper cylinder head, the second branch oil circuit, and the second oil passage provided by another embodiment of the present invention; Figure 6 It is a schematic diagram of the structure of the lower cylinder head, the third branch oil circuit, the fourth branch oil circuit, and the third oil passage provided by another embodiment of the present invention; Figure 7 It is a schematic diagram of the positional structure of the cylinder barrel, the first branch oil circuit, and the first oil passage provided by another embodiment of the present invention; Figure 8 For the present invention Figure 4 Schematic diagram of the structure at position A in the present invention; Figure 9 Schematic diagram of the structure of the multi-parameter transmitter detection device provided by another embodiment of the present invention; Among them, the reference numerals in the figure are as follows: 10. Differential pressure detection device; 11. Pressure cylinder; 110. Cylinder barrel; 111. First chamber; 112. Second chamber; 113. First communication interface; 114. Second communication interface; 115. First lubricating oil interface; 116. Upper cylinder head; 117. Lower cylinder head; 118. Sliding gasket; 12. Differential pressure piston; 13. First piston rod; 14. Flywheel; 140. Driving mechanism; 141. Guide rail; 142. Cylinder; 143. Rack; 144. Ring gear; 15. Stopper; 151. Stop piece; 16. Pusher; 161. Pushing rod; 162. Pulley; 17. Load assembly; 171. Ballast tray; 172. Calibration object; 173. Mounting tray; 18. Second piston rod; 19. Branch oil circuit system; 191. First branch oil circuit; 192. First oil passage; 193. Second branch oil circuit; 194. Second oil passage; 195. Third branch oil circuit; 196. Fourth branch oil circuit; 197. Third oil passage; 20. Static pressure module; 30. Pressure transmission system; 31. Gas source assembly; 32. First gas path; 33. Third gas path; 34. Second gas path; 35. Fourth gas path; 36. Fifth gas path; 37. One-way fluid buffer; 38. Sixth gas 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; 40. Multi-parameter transmitter to be measured; 50. Lubrication system; 51. Oil cup; 52. First oil circuit; 53. Second oil circuit; 54. Air pressure balance pipeline; 60. Drainage mechanism; 61. Drainage elastic tube; 62. Drainage outer tube; 63. Seventh control valve; 64. Thin wall section. Detailed implementation method

[0013] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0014] It should be further noted that the drawings and embodiments of the present invention mainly describe and explain 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 completely 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 specific forms and settings in a well-known manner.

[0015] 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.

[0016] The orientation terms "inside" and "outside" refer to the inside and outside of the contour of each component itself. The terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0017] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, and the meaning of "several" is one or more, unless otherwise specifically defined.

[0018] Now, a differential pressure detection device and a multi-parameter transmitter detection device provided by the present invention will be described.

[0019] The first embodiment of the present invention provides a differential pressure detection device, which includes a pressure cylinder 11, a differential pressure piston 12, a first piston rod 13, a flywheel 14, a stopper 15, a dialing member 16, a driving mechanism 140 and a load assembly 17. A sliding cavity is provided inside the pressure cylinder 11. The pressure cylinder 11 is further provided with a first communication interface 113, a second communication interface 114 and a first lubricating oil interface 115. The differential pressure piston 12 is slidably disposed in the sliding cavity and is in sealing cooperation with the inner wall of the pressure cylinder 11 to divide the sliding cavity into a first chamber 111 and a second chamber 112. The first communication interface 113 communicates with the first chamber 111, the second communication interface 114 communicates with the second chamber 112, and the first lubricating oil interface 115 communicates with the middle of the sliding cavity. One end of the first piston rod 13 is connected to the differential pressure piston 12, and the other end passes through the pressure cylinder 11 and is in sliding seal cooperation with the pressure cylinder 11. The flywheel 14 is rotatably disposed on the pressure cylinder 11 and sleeved on the first piston rod 13. The stopper 15 is fixedly disposed on the flywheel 14. The dialing member 16 is fixedly disposed on the first piston rod 13 and is in a crossed state with a spatial angle between the dialing member 16 and the stopper 15, and is used to abut against the stopper 15 and have a sliding freedom when the flywheel 14 rotates, so as to drive the first piston rod 13 to rotate. The driving mechanism 140 is in transmission connection with the flywheel 14 to give an initial rotational speed to the flywheel 14. The load assembly 17 is disposed on the first piston rod 13 and is used to apply an axial load to the first piston rod 13. Wherein, the state that the dialing member 16 and the stopper 15 are in a crossed state with a spatial angle means that an angle can be formed when the dialing member 16 and the stopper 15 contact each other so as to abut against each other, so as to transfer the rotation from the flywheel 14 to the rotation of the first piston rod 13 and the differential pressure piston 12, but does not affect the sliding between the dialing member 16 and the stopper 15, and is also convenient for the separation between the dialing member 16 and the stopper 15, that is, the above-mentioned used to abut against the stopper 15 and have a sliding freedom when the flywheel 14 rotates.

[0020] During use, it is mainly divided into the following two stages.

[0021] In the first stage, first connect the gas interfaces on both sides of the transmitter waiting to be detected to the first communication interface 113 and the second communication interface 114 through pipelines and ventilate. Then, the driving mechanism 140 is used to give the flywheel 14 an initial rotational velocity. When the flywheel 14 rotates, due to the limiting effect between the blocking member 15 and the shifting member 16, the flywheel 14 continues 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. As a result, while the lubricating oil entering through the first lubricating oil interface 115 can be evenly distributed between the first piston rod 13, the differential pressure piston 12, and the pressure cylinder 11 to reduce friction, the first piston rod 13, the differential pressure piston 12, and the pressure cylinder 11 always maintain a dynamic friction state, improving the sensitivity of 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, and at the same time, the load assembly 17 is used to load or unload the first piston rod 13 to limit the sliding amount of the differential pressure piston 12 and prevent the sliding amount of the differential pressure piston 12 from exceeding the stroke, making it difficult to measure the differential pressure data.

[0022] In the existing method, during the detection process, the process of the differential pressure pushing the piston to move changes from static friction to dynamic friction and then to static friction. The starting friction force when changing from static friction to dynamic friction is slightly greater than the dynamic friction force, making it difficult to improve the sensitivity of piston movement. In this application during the detection process, the first piston rod 13, the differential pressure piston 12, and the pressure cylinder 11 always maintain a dynamic friction state, and the entire detection process is not affected by the starting friction force, thus improving the sensitivity of piston movement.

[0023] In addition, due to this cooperation method of the blocking member 15 and the shifting member 16, when the flywheel 14 drives the first piston rod 13 and the differential pressure piston 12 to rotate, it does not overly restrict the sliding of the differential pressure piston 12 and the first piston rod 13.

[0024] In the second stage, the rotational speed of the flywheel 14 gradually decreases, causing the power transmission between the blocking member 15 and the shifting member 16 to disappear, that is, the pressure between the blocking member 15 and the shifting member 16 disappears, or the blocking member 15 and the shifting member 16 are separated, eliminating the influence of the friction between the blocking member 15 and the shifting member 16 on the movement of the differential pressure piston 12. At this time, the first piston rod 13 and the differential pressure piston 12 are still rotating under the action of inertia, and the differential pressure piston 12 can continue to move in the pressure cylinder 11 under the action of the differential pressure on both sides. At this time, the differential pressure piston 12 is neither affected by the starting friction force nor by other external friction forces, and its accuracy is in a relatively high state. At this time, the sliding distance of the differential pressure piston 12 can be read through the moving distance of the exposed end of the first piston rod 13. And the differential pressure can be calculated based on the loading amount of the load assembly 17 and the sliding distance of the differential pressure piston 12.

[0025] Such asFigures 1 to 7 As shown, in some specific embodiments, the differential pressure detection device 10 in the present invention is used to detect differential pressures in the range of 0.1 kPa - 400 kPa. The differential pressure detection device 10 achieves high-precision pressure regulation through the collaborative design of a mechanical structure and a load assembly 17. The sliding cavity inside the pressure cylinder 11 is separated into an independent first chamber 111 and a second chamber 112 by a differential pressure piston 12. A first communication interface 113 communicates with the first chamber 111 to connect to a differential pressure detection instrument, and a second communication interface 114 communicates with the second chamber 112 to access an external static pressure source; the differential pressure piston 12 is driven by a first piston rod 13 to move along its axial direction. Specifically, the movement of the differential pressure piston 12 in the axial direction is achieved by the rotation of a flywheel 14: when a stopper 15 on the flywheel 14 abuts against a pusher 16 on the first piston rod 13, the rotational movement of the flywheel 14 is converted into the linear displacement of the differential pressure piston 12, and the flywheel 14 can be driven to rotate by a driving mechanism 140; by adjusting the load assembly 17, the axial load applied to the first piston rod 13 is changed. When loading in the positive direction, the differential pressure piston 12 is pushed to compress the second chamber 112 to generate a positive pressure difference (0 - 100 kPa), and when unloading in the reverse direction, the differential pressure piston 12 retracts to expand the second chamber 112 to generate a negative pressure difference (0 - -50 kPa). A first lubricating oil interface 115 injects a lubricating medium into the middle of the sliding cavity to form a dynamic oil film to suppress frictional interference and ensure the long-term stability of the differential pressure signal.

[0026] The differential pressure piston 12 and the first piston rod 13 can be made of tungsten carbide material, the hardness of which is ≥90 HRA and the coefficient of linear thermal expansion is ≤1.5×10-6 / ℃, ensuring that the deformation is negligible. In addition, the differential pressure piston 12 and the first piston rod 13 made of this material are lightweight. Through theoretical calculation, when the diameter of the differential pressure piston 12 is 1 cm and the height is 8 cm, the generated pressure is approximately 6 kPa. Considering factors such as lightweight design and material optimization in actual working conditions, the mass of the differential pressure piston 12 and the first piston rod 13 is expected to be further reduced, thereby correspondingly reducing the overall generated pressure. In addition, since there is a pressure lower limit during measurement, when the lower limit value is relatively large, this lower limit value can make up for the weight of the differential pressure piston 12 and the first piston rod 13; when the lower limit value is relatively small and insufficient to make up for it, on the one hand, lighter materials such as titanium alloy or ceramic can be used, or a hollow structure can be adopted to reduce the weight of the differential pressure piston 12 and the first piston rod 13.

[0027] ​It should be noted that the first communication interface 113 and the second communication interface 114 are not arranged at both 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 gas path, which causes a part of the gas to be compressed. The compressed gas will form an air cushion at this position, and 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 impacted and deformed.

[0028] Compared with the prior art, the present invention drives the flywheel 14 to rotate through the driving mechanism 140 and the mechanical loading mechanism of the load assembly 17, improves the differential pressure resolution to 0.01 kPa, and supports stepless switching between positive pressure (0 - 100 kPa) and negative pressure (0 - -50 kPa), and can meet the two-way differential pressure detection requirements. For example, when generating a differential pressure of 0.1 kPa under a static pressure of 15 MPa, the repeatability error ≤ ±0.03 kPa, and the accuracy is improved by 20 times compared with the traditional solution.

[0029] In the existing differential pressure detection device 10, differential pressure drift is caused by the sliding friction between the piston and the cylinder barrel 110, especially the signal-to-noise ratio is low in the micro differential pressure section. Through the dynamic oil film lubrication technology, the present invention reduces the friction coefficient from 0.1 (dry friction) to less than 0.001. Combined with the wear-resistant characteristics of tungsten carbide materials, the differential pressure drift after continuous operation for 1000 hours < ±0.02%, and the signal-to-noise ratio in the micro differential pressure section is increased to 60 dB, which is significantly better than the traditional solution.

[0030] As Figure 3 shown, a differential pressure detection device provided by the first embodiment of the present invention, the driving mechanism 140 includes a guide rail 141, a cylinder 142, a rack 143 and a gear ring 144; the guide rail 141 is used for being fixedly arranged relative to the pressure cylinder 11; the cylinder 142 is arranged on the guide rail 141; the rack 143 is slidably arranged on the guide rail 141 and is connected with the cylinder 142 to slide on the guide rail 141 under the drive of the cylinder 142; the gear ring 144 is arranged on the flywheel 14 and meshes with the rack 143; wherein, after the rack 143 moves to a preset position, it is separated from the gear ring 144. The flywheel 14 is of a cylindrical structure, the stopper 15 includes a blocking piece 151 vertically arranged at the bottom of the flywheel 14, the dialing piece 16 includes a dialing rod 161 vertically arranged on the first piston rod 13, and a pulley 162 is arranged at the position of the dialing rod 161 for contacting the blocking piece 151 to reduce the friction force.

[0031] The operator can drive the flywheel 14 to rotate manually or by means of a motor drive. On the one hand, there is a knurling design on the edge of the flywheel 14, which can be regarded as a driving mechanism 140 and facilitates manual rotation operation. On the other hand, a pulley groove is provided on the edge of the flywheel 14, and it is driven to rotate by the motor in a belt drive manner; the two driving methods meet different usage requirements. In addition, another embodiment of the driving mechanism 140 driving the flywheel 14 to rotate is as follows.

[0032] The rotation of the flywheel 14 is realized by a cylinder 142, a rack 143, a gear ring 144 and a guide rail 141. The gear ring 144 is sleeved on the outer ring of the flywheel 14. A rack 143 meshing with the gear ring 144 is provided on one side of the gear ring 144. When the rack 143 reciprocates under the drive of the cylinder 142, the flywheel 14 can rotate in two opposite directions. In order to enable the rack 143 to reciprocate stably, a guide rail 141 is also provided. The rack 143 is slidably connected to the guide rail 141. The cylinder 142 is arranged at one end of the guide rail 141 away from the flywheel 14. The piston rod end of the cylinder 142 is connected to one end of the rack 143. The other end of the rack 143 extends towards the flywheel 14 and meshes with the gear ring 144. When the cylinder 142 expands and contracts, the flywheel 14 can be driven to rotate through the expansion and contraction of the rack 143. Among them, after the rack 143 moves to a preset position, it separates from the gear ring 144, and the rack 143 actively disengages from the gear ring 144 at the preset position to cut off the power transmission and avoid reverse impact; the flywheel 14 rotates under the action of inertia until it stops slowly.

[0033] The side wall of the flywheel 14 is vertically provided with scales, and a pointer is also provided on the first piston rod 13. The pointer is located above the dial rod 161. The height of the differential pressure piston 12 rising or falling can be determined through the pointer, and further, the magnitude of the pressure change value in the first chamber 111 or the second chamber 112 can be obtained.

[0034] By operating the driving mechanism 140, the position of the differential pressure piston 12 in the sliding cavity is changed, and further, the pressure in the first chamber 111 or the second chamber 112 is changed; the driving mechanism 140 controls the rotational movement of the flywheel 14. The flywheel 14 is rotatably arranged at the top of the pressure cylinder 11. A bearing is provided between the pressure cylinder 11 and the flywheel 14 to ensure that the flywheel 14 can rotate continuously. The flywheel 14 is of a cylindrical structure, and two stoppers 15 are symmetrically arranged at the bottom edge of the flywheel 14. Each stopper 15 includes a stopper piece 151 vertically arranged at the bottom of the flywheel 14. When the flywheel 14 rotates, the stopper piece 151 at the bottom of the flywheel 14 also rotates. During the rotation of the stopper piece 151, the pulley 162 contacts the corresponding stopper piece 151. The stopper piece 151 only exerts a horizontal thrust on the dial member 16, converting the rotational movement of the flywheel 14 into the up and down 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 during the up and down movement of the differential pressure piston 12 and the first piston rod 13.

[0035] As shown Figures 2 to 4 in the figure, a differential pressure detection device provided by the first embodiment of the present invention has a pressure cylinder 11 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 in sliding and sealing fit 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.

[0036] 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 avoid tilting and jamming of the differential pressure piston 12 at the limit position.

[0037] 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 installed 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 by 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 surfaces are treated with 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 magnitudes of pressure 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 displace, and the pressure in the sliding cavities at the upper and lower ends of the differential pressure piston 12 changes; 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 reversibly usable.

[0038] The differential pressure detection device 10 is used to detect differential pressure. A sliding cavity is arranged inside the pressure cylinder 11, and the differential pressure piston 12 is slidably arranged in the sliding cavity and is in sealing fit with the inner wall of the pressure cylinder 11, dividing 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, the upper end passes through the pressure cylinder 11, and is in sliding and sealing fit with the pressure cylinder 11, and a ballast tray 171 is arranged at the upper end of the first piston rod 13.

[0039] 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 within the sliding cavity to achieve positive pressure detection.

[0040] When it is necessary to switch to the negative pressure mode, there are two operation methods. The first method is to flip the ballast tray 171. With the assistance of a bracket, the pressure cylinder 11 is connected to the bracket rotating shaft. By flipping the pressure cylinder 11 by 180°, the ballast tray 171 is also inverted, causing the ballast tray 171 that was originally above the pressure cylinder 11 to flip to below. At this time, the position where 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. Through this flipping operation, the force-bearing states at both ends of the differential pressure piston 12 are changed to achieve negative pressure detection.

[0041] Another method is not to flip the ballast tray 171, but only to exchange the positive and negative pressure detection pipelines to achieve negative pressure detection. 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 method, the position of the ballast tray 171 remains unchanged, and the mode conversion is achieved through pipeline switching, reducing the operation complexity and potential wear caused by mechanical flipping, while also ensuring the accuracy and stability of detection. Through the above two implementation methods of the negative pressure mode, the load component 17 of this embodiment can flexibly switch between the positive pressure and negative pressure modes to meet diverse detection requirements.

[0042] As Figures 4 to 7 shown, a differential pressure detection device provided by the first embodiment of the present invention has a first oil hole and a first oil passage 192 corresponding to the sliding surface of the differential pressure piston 12 in the middle of the pressure cylinder 11; a second oil hole and a second oil passage 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 passage 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 passage 192, the second oil hole and the second oil passage 194, and the third oil hole and the third oil passage 197 are all connected to the first lubricating oil interface 115, and lubricating medium is supplied to the respective corresponding sliding surfaces through the internal branch oil passage system 19.

[0043] The internal sliding cavity of the pressure cylinder 11 provides a sliding space for the differential pressure piston 12, the first piston rod 13, and the second piston rod 18. Specifically, the first oil hole is connected to the annular first oil passage 192 opened in the wall of the pressure cylinder 11. The first oil passage 192 surrounds the middle of the pressure cylinder 11, and its position exactly corresponds to the sliding area of the differential pressure piston 12, ensuring that the lubricating medium can be directly delivered to the contact surface between the differential pressure piston 12 and the inner wall of the pressure cylinder 11.

[0044] At the upper end of the pressure cylinder 11, a second oil hole and a second oil passage 194 are provided. The second oil hole communicates with the second oil passage 194, and the outlet position of the second oil passage 194 precisely corresponds to the sliding surface where the first piston rod 13 penetrates through the pressure cylinder 11, ensuring that the lubricating medium can accurately lubricate the sliding seal area between the first piston rod 13 and the pressure cylinder 11. Similarly, at the lower end of the pressure cylinder 11, a third oil hole and a third oil passage 197 are provided. The third oil hole communicates with the third oil passage 197, and the lubricating medium flows through the third oil hole and the third oil passage 197 to the area where the second piston rod 18 is in sliding contact with the lower end of the pressure cylinder 11.

[0045] The first lubricating oil interface 115, as the inlet of the external lubricating medium, is provided at the lower end of the pressure cylinder 11. The first lubricating oil interface 115 is respectively communicated with the first oil hole, the second oil hole, the third oil hole, the first oil passage 192, the second oil passage 194, and the third oil passage 197 through the internal branch oil passage system 19. Specifically, the lubricating medium enters from the first lubricating oil interface 115 and flows into the first oil passage 192, the second oil passage 194, and the third oil passage 197 in a parallel manner, and flows to the corresponding sliding surfaces to achieve efficient lubrication.

[0046] This design of setting multiple groups of oil holes and oil passages on the pressure cylinder 11 and realizing unified oil supply through the first lubricating oil interface 115 has significant beneficial effects. First, by independently setting oil holes and oil passages for the sliding surfaces at different positions of the differential pressure piston 12, the first piston rod 13, and the second piston rod 18, the lubricating medium can be accurately distributed according to the working characteristics and lubrication requirements of each component, effectively reducing sliding friction, reducing component wear, and extending the service life of the differential pressure detection device 10. Second, the communication design between the internal branch oil passage system 19 and the first lubricating oil interface 115 simplifies the structure of the lubrication system 50, avoids the oil passage chaos and sealing problems that may be caused by 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 detection result caused by the fluctuation of the frictional resistance, and thus greatly improve the measurement accuracy and sensitivity of the differential pressure detection device 10 to meet the requirements of high-precision detection.

[0047] Such as Figures 2 to 7As shown in the figure, a differential pressure detection device 10 provided by another embodiment of the present invention, the pressure cylinder 11 includes 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 arranged at the upper and lower ends of the cylinder barrel 110; a second oil hole and a second oil passage 194 are provided in the upper cylinder head 116, and a third oil hole and a 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 head 116, and a second sliding hole is provided at the center of the lower cylinder head 117. Sliding gaskets 118 are provided in both the first sliding hole and the second sliding hole. The first sliding hole is slidably and sealingly fitted with the first piston rod 13 through the sliding gasket 118, and the second sliding hole is slidably and sealingly fitted with the second piston rod 18 through the sliding gasket 118; a limiting boss is provided on the outer periphery of the sliding gasket 118, and the limiting boss is snap-fitted with an annular groove on the inner wall of the upper cylinder head 116 or the lower cylinder head 117.

[0048] The pressure cylinder 11 is designed with a split structure and is composed 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 installed at the upper and lower ends of the cylinder barrel 110 respectively by means of threaded connection to form a complete pressure sealing chamber. A second oil hole is radially opened inside the upper cylinder head 116. One end of the second oil hole communicates with the first lubricating oil interface 115, and the other end is connected to an annular second oil passage 194 opened circumferentially along the inner wall of the upper cylinder head 116. Similarly, a third oil hole and an annular third oil passage 197 are provided in the lower cylinder head 117, and their connection methods are similar to those 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 areas of the upper cylinder head 116 and the lower cylinder head 117.

[0049] A first sliding hole is provided at the central position of the upper cylinder head 116, and a second sliding hole is provided at the position of 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. An annular gap is formed between the first sliding hole and the first piston rod 13 for installing the sliding gasket 118. A limiting boss is provided on the outer peripheral surface of the sliding gasket 118, and the outer diameter of the limiting boss is snap-fitted with an annular groove on the inner wall of the upper cylinder head 116 to realize the axial limit of the sliding gasket 118. A plurality of diversion holes are provided in the circumferential direction of the sliding gasket 118. Both ends of the diversion holes penetrate the inner and outer surfaces of the sliding gasket 118 respectively. The diversion holes are used to divert the lubricating oil stored in the second oil passage 194 in the upper cylinder head 116 to the inner surface of the sliding gasket 118, so that when the first piston rod 13 moves up and down, a continuous lubricating film can be formed on the sliding surfaces of the first piston rod 13 and the sliding gasket 118.

[0050] Similarly, the inner diameter of the second sliding hole is slightly larger than the outer diameter of the second piston rod 18. An annular gap is formed between the second sliding hole and the second piston rod 18 for installing the sliding gasket 118. A limiting boss is provided on the outer peripheral surface of the sliding gasket 118, and the outer diameter of the limiting boss is in snap-fit connection with the annular groove on the inner wall of the lower cylinder head 117 to achieve the axial limit of the sliding gasket 118. A plurality of diversion holes are provided in the circumferential direction of the sliding gasket 118. Both ends of the diversion holes penetrate the inner and outer surfaces of the sliding gasket 118 respectively. The diversion holes are used to divert the lubricating oil stored in the third oil passage 197 in the lower cylinder head 117 to the inner surface of the sliding gasket 118, so that when the lubricating medium moves up and down the second piston rod 18, a continuous lubricating film can be formed on the sliding surface between the second piston rod 18 and the sliding gasket 118.

[0051] This split-type pressure cylinder 11 structure and sliding seal design have many technical advantages. First, the independent design of the upper cylinder head 116 and the lower cylinder head 117 is convenient for processing and assembly. Different materials and processing technologies can be selected according to different sealing requirements, improving the sealing performance and service life. Second, the sliding gasket 118 is effectively prevented from displacement or flipping during the reciprocating movement of the piston rod through the snap-fit connection between the limiting boss and the annular groove, ensuring the reliability and stability of the seal.

[0052] As Figures 2 to 7 shown, a differential pressure detection device provided by another embodiment of the present invention. The first lubricating oil interface 115 is connected to the first oil hole and the first oil passage 192, the second oil hole and the second oil passage 194, and the third oil hole and the third oil passage 197 through the branch oil passage system 19; the branch oil passage system 19 includes a first branch oil passage 191, a second branch oil passage 193, and a third branch oil passage 195; the first branch oil passage 191 is horizontally arranged, one end of which extends towards the side wall of the sliding cavity and is connected to the first oil passage 192 through the first oil hole; the second branch oil passage 193 is an L-shaped structure, the vertical section of which extends upwards from the first branch oil passage 191 into the upper cylinder head 116, and the horizontal section of the first branch oil passage 191 extends towards the through hole direction and is connected to the second oil passage 194 through the second oil hole; the third branch oil passage 195 is vertically arranged, extends from the first branch oil passage 191 towards the lower cylinder head 117 direction, and penetrates the lower cylinder head 117 to connect to the external lubrication system 50; the fourth branch oil passage 196 is horizontally arranged in the lower cylinder head 117, one end of which is connected to the third branch oil passage 195, and the other end is connected to the third oil passage 197 through the third oil hole.

[0053] The first lubricating oil interface 115 serves as the total inlet of the lubricating medium, and realizes the precise oil supply to different sliding surfaces through the branch oil passage system 19. The branch oil passage system 19 is composed of a first branch oil passage 191, a second branch oil passage 193, a third branch oil passage 195, and a fourth branch oil passage 196.

[0054] The first branch oil passage 191 is arranged horizontally, and one end thereof extends towards the side wall of the sliding cavity of the pressure cylinder 11. The first branch oil passage 191 is connected to the first oil passage 192 surrounding the middle part of the sliding cavity through a first oil hole, ensuring that the lubricating medium can be timely transported to the contact surface between the differential pressure piston 12 and the inner wall of the pressure cylinder 11.

[0055] The second branch oil passage 193 adopts an L-shaped structure. Its vertical section extends upward from the first branch oil passage 191, passes through a part of the cylinder barrel 110 of the pressure cylinder 11, and reaches the inside of the upper cylinder head 116. After entering the upper cylinder head 116, the horizontal section of the second branch oil passage 193 extends towards the through hole, and a sliding gasket 118 that is slidably and sealingly fitted with the first piston rod 13 is installed in this through hole. The second branch oil passage 193 is connected to the second oil passage 194 circumferentially arranged along the inner wall of the upper cylinder head 116 through a second oil hole, enabling the lubricating medium to effectively lubricate the sliding sealing part between the first piston rod 13 and the upper cylinder head 116.

[0056] The third branch oil passage 195 is arranged vertically downward, extends from the first branch oil passage 191 towards the lower cylinder head 117, and penetrates through the lower cylinder head 117. The end of the third branch oil passage 195 is connected to an external lubricating medium supply device through a first lubricating oil interface 115. Meanwhile, a horizontally extending fourth branch oil passage 196 is provided in the lower cylinder head 117. One end of the fourth branch oil passage 196 is connected to the third branch oil passage 195, and the other end is connected to the third oil passage 197 circumferentially arranged along the inner wall of the lower cylinder head 117 through a third oil hole, thereby transporting the lubricating medium to the sliding contact area between the second piston rod 18 and the lower cylinder head 117.

[0057] Through the branch oil passages with different structures and orientations, it is possible to achieve precise distribution and efficient transportation of the lubricating medium according to the working characteristics and lubrication requirements of the differential pressure piston 12, the first piston rod 13, and the second piston rod 18. Secondly, the reasonable layout of the oil passages and the design of the sealing structure ensure the stability and tightness of the lubricating medium during transportation, reduce component wear caused by lubricating medium leakage or insufficient supply, extend the service life of the differential pressure detection device 10, and at the same time ensure the reliability of the device operation and the accuracy of the detection results.

[0058] As Figures 4 to 8 shown, a differential pressure detection device provided by another embodiment of the present invention, the differential pressure detection device 10 further includes a liquid drainage mechanism 60. The liquid drainage mechanism 60 includes a drainage elastic tube 61, a drainage outer tube 62, and a seventh control valve 63. One end of the lower cylinder head 117 near the second chamber 112 is provided with a drainage hole, and a relief hole communicating therewith is arranged below the drainage hole. The lower end of the relief hole penetrates through the bottom of the lower cylinder head 117, and the diameter of the relief hole is larger than that of the drainage hole. The drainage and discharge flexible tube 61 is located within the avoidance hole, and one end thereof is connected to the drainage and discharge hole. The outer drainage tube 62 is connected to the other end of the drainage and discharge flexible tube 61. The seventh control valve 63 is disposed on the outer drainage tube 62. Among them, the drainage and discharge flexible tube 61 has an N-shaped bent structure, and a thin-wall section 64 is provided at a position close to the second chamber 112 to expand under pressure and squeeze the portion away from the second chamber 112 against the side wall of the avoidance hole for sealing.

[0059] Further, the liquid discharge mechanism 60 includes a drainage and discharge flexible tube 61, an outer drainage tube 62, and a seventh control valve 63. A drainage and discharge hole and an avoidance hole are sequentially arranged on the lower cylinder head 117 in the vertical direction. The diameter of the avoidance hole is larger than that of the drainage and discharge hole, which facilitates the installation of the drainage and discharge flexible tube 61. The drainage and discharge hole is communicated with the bottom of the second chamber 112, and the lower end of the avoidance hole penetrates through the lower cylinder head 117 and is communicated with the atmosphere; The drainage and discharge flexible tube 61 has an N-shaped bent structure. One end thereof is hermetically connected to the drainage and discharge hole, and the other end passes through the avoidance hole and is connected to the outer drainage tube 62. The seventh control valve 63 is installed on the outer drainage tube 62 to control the on-off of the oil. A thin-wall section 64 is provided at a position of the drainage and discharge flexible tube 61 close to the first cavity 103.

[0060] When the system is in the working state, the internal pressure of the cylinder barrel 110 increases. The thin-wall section 64 expands outward under pressure, pushing the distal end of the drainage and discharge flexible tube 61 to closely fit against the side wall of the avoidance hole to form a dynamic seal and prevent the leakage of the lubricating medium. When the system stops working or the internal pressure abnormally increases, the internal pressure of the cylinder barrel 110 decreases or exceeds the limit. The thin-wall section 64 retracts, and the drainage and discharge flexible tube 61 returns to the bent state. The lubricating medium is discharged through the outer drainage tube 62 via the seventh control valve 63 to achieve pressure relief and discharge.

[0061] A multi-parameter transmitter detection device provided by the second embodiment of the present invention includes the above-mentioned differential pressure detection device 10, static pressure module 20, and pressure transmission system 30. The static pressure module 20 is used to generate static pressure or gauge pressure. The pressure transmission system 30 is respectively connected to the differential pressure detection device 10 and the static pressure module 20, and is provided with an interface component for connecting to the multi-parameter transmitter 40 to be measured, and is used to transmit pressure through a gas medium.

[0062] As Figure 1 shown, when the pressure detection device in the present invention works, the differential pressure detection device 10 is used to detect a differential pressure in the range of 0.1 kPa - 400 kPa; the static pressure module 20 is used to generate a static pressure or gauge pressure in the range of 0.1 MPa - 100 MPa. The specific working process is as follows: Connect the multi-parameter transmitter 40 under test to the pressure transmission system 30 through the interface component. If differential pressure needs to be detected, operate the load component 17. The load component 17 changes the position of the first piston rod 13, causing the differential pressure piston 12 to displace in the first cavity, thereby changing the pressure in the first cavity 111 or the second cavity 112. Then, open the relevant pipeline valves of the pressure transmission system 30 to allow the gas medium to enter the first cavity 111 or the second cavity 112, forming a differential pressure in the range of 0.1 kPa - 400 kPa.

[0063] When static pressure or gauge pressure is detected, close some pipeline valves and open the valves related to the static pressure module 20. The static pressure module 20 generates a static pressure or gauge pressure in the range of 0.1 MPa - 100 MPa and transmits it to the detection part through the pressure transmission system 30. If the system pressure needs to be adjusted, the pressure transmission system 30 can be connected through the corresponding pipeline for the replenishment or release of the gas medium. During the pressure detection process, if it is necessary to balance the pressures at both ends of the differential pressure piston 12, the pressure balance can be achieved by opening the specific pipeline connection valve.

[0064] Compared with the prior art, through the integrated design of the differential pressure detection device 10 and the static pressure module 20, this pressure detection device organically combines the function of accurately detecting the differential pressure performance of the multi-parameter transmitter 40 under test by the differential pressure piston 12 with the ability of the general piston to meet the multi-dimensional measurement requirements such as absolute pressure and gauge pressure. While optimizing the overall structure, it effectively reduces the device volume, shortens the pressure transmission path, and reduces the error during the pressure transmission process, enabling the differential pressure detection device 10 in the present invention to efficiently and accurately complete the detection work of the multi-parameter transmitter under different pressure parameters, greatly improving the detection efficiency and reliability, and meeting the diverse and high-precision detection requirements.

[0065] A multi-parameter transmitter detection device provided by the second embodiment of the present invention, the pressure delivery system 30 includes: a gas source assembly 31, a first gas path 32, a second gas path 34, a third gas path 33, a fourth gas path 35, a fifth gas path 36, a sixth gas path 38 and a one-way fluid buffer 37; the gas source assembly 31 is connected to the static pressure module 20 for supplying a gas medium; the first gas path 32 is respectively connected to the first communication interface 113 and the negative pressure port of the interface assembly, and a first control valve 321 is provided on the first gas path 32 for controlling the on-off of the gas medium in the first gas 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 gas 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 at one end of the third gas 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 a sixth control valve 332 is provided at one end of the third gas path 33 close to the static pressure module 20 for adjusting the gas pressure output from the static pressure module 20 to the third gas path 33; the second gas path 34 is respectively connected to the first gas path 32 and the third gas path 33, and a second control valve 341 is provided thereon for controlling the 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; the fourth gas path 35 is respectively connected to the third gas path 33 and the outlet end of the gas source assembly 31, and a fifth control valve 351 is provided thereon for controlling the fluid communication between the gas source assembly 31 and the third gas path 33 to supplement or release the gas medium; the fifth gas path 36 is respectively connected to the third gas path 33 and the positive pressure port of the interface assembly for outputting the gas medium in the multi-parameter transmitter 40 to be measured; the one-way fluid buffer 37 is used to provide pressure compensation; the sixth gas path 38 is respectively connected to the one-way fluid buffer 37 and the first gas path 32, and a fourth control valve 381 is provided thereon.

[0066] As Figures 1 to 7 shown, when the pressure delivery system 30 in the present invention is working, each component operates in coordination to achieve precise control and pressure regulation of the gas medium (such as nitrogen), and the specific process is as follows: Before the measurement starts, the operator pre-loads 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 through the first piston rod 13, driving the differential pressure piston 12 to move in the sliding cavity to form an initial mechanical pressure reference for subsequent differential pressure detection; at the same time, the gas source assembly 31 pre-stores a sufficient amount of gas medium and provides a stable pressure source reserve for the system through the connection with the static pressure module 20.

[0067] The process of generating static pressure is as follows. First, the air source assembly 31, as a pressure source for storing fluid medium, provides an initial pressure input to the static pressure module 20 through the third air path 33. The sixth control valve 332 preliminarily adjusts the gas pressure entering the static pressure module 20 to control the pressure magnitude. Secondly, the static pressure module 20 is equipped with weights of different specifications. By loading the weights onto the static pressure piston, the gravity of the weights is superimposed on the gas pressure provided by the air source assembly 31. For example, when the number of weights increases, the total pressure increases; when it decreases, the pressure decreases. Finally, a pressure regulator is also provided between the air source assembly 31 and the static pressure module 20. The pressure regulator is a piston structure with a screw. By rotating the screw, the piston can move in the cavity to change the internal gas volume. According to the principles related to the state of the gas, the volume change will cause a change in pressure, thereby finely adjusting the gas pressure flowing to the static pressure module 20, so that the static pressure module 20 generates a high-precision static pressure value for detecting the static pressure measurement performance of the multi-parameter transmitter 40 to be measured. By comparing the output value of the device to be measured with the actual static pressure value, its accuracy is evaluated.

[0068] When differential pressure detection needs to be performed on the multi-parameter transmitter 40 to be measured, first, start the static pressure module 20 to a stable working state, and open the first control valve 321, the second control valve 341, the third control valve 331, and the fourth control valve 381 to ensure that each pipeline of the pressure transmission system 30 is connected and the fluid medium flows normally. Secondly, close the second control valve 341 to cut off the pressure balance between the first chamber 111 and the second chamber 112; open the fourth control valve 381 provided on the sixth air path 38. The fourth control valve 381 is used to control the entry and exit of gas medium into and out of the one-way fluid buffer 37 to adjust the pressure output of the one-way fluid buffer 37; by adjusting the one-way fluid buffer 37, change the pressure on the negative pressure side of the multi-parameter transmitter 40 to be measured to generate a pressure difference at both ends of the differential pressure piston 12; for example, when the pressure on the negative pressure side increases, the differential pressure piston 12 moves to one side; otherwise, it moves in the opposite direction. Thirdly, 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 of the first chamber 111 and the second chamber 112 by adjusting the first control valve 321, the third control valve 331, the sixth control valve 332, and the fifth control valve 351 to align the pointer with the corresponding scale on the side wall of the flywheel 14 and maintain its working height. Finally, the stable pressure difference is transmitted through the positive and negative pressure ports of the multi-parameter transmitter 40 to be measured. The static pressure is measured from the positive pressure side, and the differential pressure is used for flow detection. By comparing the output value of the device to be measured with the actual differential pressure value, its measurement accuracy is evaluated.

[0069] It can be seen from this 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 balance stage, the second control valve 341 is opened to connect the first chamber 111 and the second chamber 112 through the second gas 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 at the same time, 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 gas path 38 to achieve dynamic pressure compensation; Fourth, in the medium recovery stage: after the detection is completed, the fifth gas path 36 is opened to discharge the gas medium in the multi-parameter transmitter through the interface component to complete the medium recovery.

[0070] Through the orderly cooperation of each air pressure pipeline and the control valve group, the pressure transmission system 30 realizes the comprehensive control of the on-off, flow direction and pressure of the gas medium, providing a stable and accurate pressure environment for the detection of the multi-parameter transmitter.

[0071] As Figures 1 to 7 shown, a multi-parameter transmitter detection device provided by the second embodiment of the present invention further includes a lubrication system 50. The lubrication system 50 provides a 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 path 52, a second oil path 53 and an air pressure balance pipeline 54; The oil cup 51 is used to store the lubricating medium; One end of the first oil path 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 head 116; The sliding surface of the second piston rod 18 and the lower cylinder head 117; One end of the second oil path 53 is connected to the oil cup 51 and the other end is connected to the static pressure module 20 for providing a 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 transmission system 30 for balancing the pressure between the inside of the lubrication system 50 and the pressure transmission system 30.

[0072] Inject a suitable lubricating medium into the lubrication system 50 and transport it to each lubricating part of the differential pressure detection device 10 and the static pressure module 20 through the oil pipeline to ensure good lubrication of each component. The lubrication system 50 realizes the efficient lubrication and reliable sealing of the core components of the pressure detection device through reasonable structural design and gas medium transmission mechanism. The specific working process is as follows: 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 passage 52, and a second oil passage 53. Among them, a certain gap is reserved above the liquid level in the oil cup 51. This design is based on the characteristics of the thermal expansion and contraction of the lubricating medium. When the equipment operates, the heat generated will cause the lubricating medium to heat up and expand. If the oil cup 51 is completely filled, the internal pressure will rise sharply, which may cause the seal of the oil cup 51 to fail, resulting in oil leakage, and even pose more serious safety hazards. The reserved gap can provide a buffer space for the expansion of the oil, ensuring the stable and safe operation of the lubrication system 50.

[0073] 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 interface 115 of the differential pressure detection device 10, for supplying lubricating medium to the following lubricating surfaces; the lubricating surfaces include: the sliding surfaces between the differential pressure piston 12 and the inner wall of the pressure cylinder 11, the sliding surfaces between the first piston rod 13 and the sliding seal gasket 118, and the sliding surfaces between the second piston rod 18 and the sliding seal gasket 118; A dot matrix structure with a depth of 2 microns is laser engraved on the inner wall of the pressure cylinder 11. Its tiny pits can store lubricating medium. When the differential pressure piston 12 moves, the lubricating medium is brought into the pressure cylinder 11, and part of it enters the dot matrix space and remains. Subsequently, it continuously replenishes the lubrication for the friction surface between the differential pressure piston 12 and the inner wall of the pressure cylinder 11, effectively reducing the friction force. In addition, the dot matrix structure can also be replaced by grooves with specific patterns, and both can achieve the functions of storing lubricating medium and reducing friction.

[0074] The second oil passage 53 is responsible for lubricating the static pressure module 20. One end of the second oil passage 53 is connected to the bottom of the oil cup 51 through a tee pipe, and the other end is connected to the internal oil passage of the static pressure module 20. The static pressure module 20 includes a static pressure piston and a static pressure cylinder. During the reciprocating movement of the static pressure piston, the second oil passage 53 continuously conveys lubricating medium to the static pressure module 20, forming an effective lubricating film in the sliding fit area between the static pressure piston and the inner wall of the static pressure cylinder, reducing component wear, and ensuring the operation accuracy and reliability of the static pressure module 20.

[0075] The air pressure balance pipeline 54 is respectively connected to the upper part of the oil cup 51 and the pressure transmission system 30. Its function is to balance the pressure between the lubrication system 50 and the pressure transmission system 30. When the pressure in the pressure transmission system 30 increases, the pressure sensor in the air pressure balance pipeline 54 detects the pressure change and controls the valve to open, introducing part of the gas in the pressure transmission system 30 into the top space of the oil cup 51, so that the pressure in the lubrication system 50 is balanced with the pressure transmission system 30, avoiding the leakage of the lubrication medium through the oil pipeline or the sealing place due to the pressure difference; when the pressure in the pressure transmission system 30 decreases, the air pressure balance pipeline 54 discharges the excess gas in the oil cup 51 to the pressure transmission system 30 to maintain the stability of the system pressure. In addition, the air pressure balance pipeline 54 can also prevent the lubrication medium in the oil cup 51 from overflowing or being sucked into the pressure transmission system 30 due to pressure fluctuations, ensuring the stable operation of the lubrication system 50 and the pressure transmission system 30 respectively.

[0076] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention.

Claims

1. A differential pressure detection device, characterized in that, include: A pressure cylinder (11) having 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 cooperating 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 slidably and sealingly engaged 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 shifting member (16) fixedly mounted on the first piston rod (13) and intersecting with the stopper (15) at a spatial angle, and configured to abut against the stopper (15) and have a sliding freedom when the flywheel (14) rotates, so as to drive the first piston rod (13) to rotate; A driving mechanism (140) is drivingly connected to the flywheel (14) to provide the flywheel (14) with an initial speed of rotation; 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, characterized in that, The driving mechanism (140) comprises: A guide rail (141) used for being fixedly arranged relative to the pressure cylinder (11); A cylinder (142) disposed 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 gear ring (144) is disposed on the flywheel (14) and meshes 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) comprises a blocking plate (151) vertically arranged at the bottom of the flywheel (14), the shifting member (16) comprises a shifting rod (161) vertically arranged on the first piston rod (13), and a pulley (162) is provided on the shifting rod (161) at a position for contacting the blocking plate (151).

4. The differential pressure detection device according to claim 3, characterized in that: 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 slidably sealed with the pressure cylinder (11); The load component (17) includes: A ballast tray (171), which is arranged above the pressure cylinder (11) and is connected to the upper end of the first piston rod (13) for placing a calibration object (172); A mounting tray (173), which is arranged 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, characterized in that: In the middle of the pressure cylinder (11), there are a first oil hole and a first oil passage (192) corresponding to the sliding surface of the differential piston (12); at the upper end of the pressure cylinder (11), there are a second oil hole and a second oil passage (194) corresponding to the sliding surface of the first piston rod (13); at the lower end of the pressure cylinder (11), there are a third oil hole and a third oil passage (197) corresponding to the sliding surface of the second piston rod (18); the first oil hole and the first oil passage (192), the second oil hole and the second oil passage (194), and the third oil hole and the third oil passage (197) are all communicated with the first lubricating oil interface (115).

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

7. The differential pressure detection device according to claim 6, wherein: The differential pressure detection device (10) further includes a liquid discharge mechanism (60). The liquid discharge mechanism (60) includes a liquid discharge elastic tube (61), a liquid discharge outer tube (62), and a seventh control valve (63). One end of the lower cylinder head (117) close to the second chamber (112) is provided with a liquid discharge hole. A relief hole communicating with the liquid discharge hole is arranged below the liquid discharge hole. The lower end of the relief hole penetrates through the bottom of the lower cylinder head (117), and the diameter of the relief hole is larger than that of the liquid discharge hole. The liquid discharge elastic tube (61) is located in the relief hole and is hermetically connected to the liquid discharge hole at one end. The liquid discharge outer tube (62) is connected to the other end of the liquid discharge elastic tube (61). The seventh control valve (63) is arranged on the liquid discharge outer tube (62). Wherein, the liquid discharge elastic tube (61) is in an N-shaped bending structure, and a thin-walled section (64) is arranged at a position close to the second chamber (112) to expand under pressure and squeeze the part away from the second chamber (112) against the side wall of the relief hole to close it.

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

9. The multi-parameter transmitter detection device according to claim 8, wherein, The pressure transmission system (30) includes: A gas source component (31) connected to the static pressure module (20) for supplying a gas medium; A first gas path (32) is respectively connected to the first communication interface (113) and the negative pressure port of the interface component. A first control valve (321) is arranged on the first gas path (32) for controlling the on / off of the gas medium in the first gas 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. A third gas path (33) is respectively connected to the second communication interface (114) and the static pressure module (20). A third control valve (331) is arranged at one end of the third gas 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). A sixth control valve (332) is arranged at one end of the third gas path (33) close to the static pressure module (20) for adjusting the gas pressure output from the static pressure module (20) to the third gas path (33). A second gas path (34) is respectively connected to the first gas path (32) and the third gas path (33), and a second control valve (341) is arranged thereon for controlling the 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). The fourth gas path (35) is respectively connected to the outlet end of the third gas path (33) and the gas source assembly (31), and is provided with a fifth control valve (351) for controlling the fluid communication between the gas source assembly (31) and the third gas path (33) to supplement or release the gas medium; The fifth gas path (36) is respectively connected to the third gas path (33) and the positive pressure port of the interface assembly, and is used for outputting the gas medium in the multi-parameter transmitter under test (40); The one-way fluid buffer (37) is used for providing pressure compensation; The sixth gas path (38) is respectively connected to the one-way fluid buffer (37) and the first gas path (32), and is provided with a fourth control valve (381) thereon.

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). The lubrication system (50) provides a lubricating medium for the differential pressure detection device (10) and the static pressure module (20). The lubrication system (50) includes: An oil cup (51) for storing the lubricating medium; A first oil path (52) with one end communicating with the oil cup (51) and the other end communicating with the first lubricating oil interface (115) of the differential pressure detection device (10); A second oil path (53) with one end communicating with the oil cup (51) and the other end connected to the static pressure module (20) for providing a lubricating medium for the static pressure module (20); An air pressure balance pipeline (54) is respectively connected to the upper part of the oil cup (51) and the pressure transmission system (30) for balancing the pressure between the inside of the lubrication system (50) and the pressure transmission system (30).

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