Explosion-proof pressure transmitter for pressure sensors

Abstract

The application discloses an explosion-proof pressure transmitting device for a pressure sensor, which comprises a shell, a support frame fixedly connected to the upper end of the shell, an electric control assembly arranged on the support frame, a switching assembly arranged on the shell, the switching assembly comprising a shaft rod rotationally connected to the inner wall of the shell, a strain assembly arranged on the shaft rod, a conductive sheet arranged on the inner wall of the shell, and the shaft rod extending through the shell and arranged outside the shell. In the technical field of pressure measurement, the strain assembly is arranged in cooperation with the electric push rod and the driving rod, the rack assembly is moved by the driving rod, the strain assembly is switched by the cooperation of the gear, the detection range of the electric control assembly is changed, the single detection range is expanded into multiple independent detection intervals with high precision, and the switching is automatically performed when the pressure exceeds the detection range, so that the pressure detection precision is ensured and the pressure transmitting device has a large detection range.

Description

Technical Field

[0001] This invention relates to the field of pressure measurement technology, and in particular to an explosion-proof pressure transmitter for pressure sensors. Background Technology

[0002] A pressure transmitter is a device that converts pressure into pneumatic or electrical signals for control and remote transmission. It can convert the physical pressure parameters of gas, liquid, etc., sensed by the pressure sensing element sensor into standard electrical signals to supply secondary instruments such as indicators, alarms, recorders, and regulators for measurement, indication, and process regulation. It can not only detect whether there is leakage or underpressure in the pipeline, but also play a role in explosion-proof regulation.

[0003] In existing explosion-proof pressure transmitters for pressure sensors, strain gauges are typically bonded tightly to a substrate that generates mechanical strain using a special adhesive. However, in practical applications, the smaller the deformation of the substrate under pressure, the wider the pressure detection range but the lower the accuracy. Conversely, the larger the deformation of the substrate under pressure, the higher the accuracy but the smaller the detection range. This makes it difficult to accurately monitor pipelines with large pressure variations during practical use. To address this issue, we propose an explosion-proof pressure transmitter for pressure sensors. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and to propose an explosion-proof pressure transmitter for pressure sensors.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An explosion-proof pressure transmitter for a pressure sensor includes a housing, a support frame fixedly connected to the upper end of the housing, an electrical control component mounted on the support frame, and a switching component mounted on the housing.

[0007] The switching assembly includes a shaft rotatably connected to the inner wall of the housing, on which a strain gauge is mounted. A conductive sheet is mounted on the inner wall of the housing. One end of the shaft penetrates the housing and extends to the outside of the housing. A gear is fixedly fitted onto the shaft located outside the housing. An electro-hydraulic actuator is fixedly connected to the side wall of the housing, and a drive rod is fixedly connected to the lower end of the electro-hydraulic actuator. A through hole is formed in the side wall of the drive rod. A symmetrically arranged rack assembly is fixedly and slidably connected to the side wall of the housing near the drive rod, and a limiting hole matching the through hole is formed on the rack assembly. A return spring is fixedly connected to the side wall of the housing, and a portal frame is fixedly connected to the end of the return spring away from the housing. A limiting rod is slidably connected inside the portal frame, and the limiting rod passes through the through hole and the limiting hole. An electromagnet is fixedly connected to the side wall of the housing away from the return spring. Both the electromagnet and the electro-hydraulic actuator are electrically connected to the electronic control assembly. The switching assembly can switch the strain gauge when the pressure change exceeds the detection range to ensure high-precision, wide-range detection.

[0008] Preferably, the strain assembly includes a frame, which is fixedly connected to the shaft via a connecting rod. Multiple mechanical strain substrates with different elastic coefficients are embedded in the polygonal frame, and strain gauges are disposed on the mechanical strain substrates.

[0009] Preferably, the strain assembly includes a circular shell fixedly connected to the shaft, the inner wall of the circular shell is fixedly connected to multiple partitions, and the side wall of the circular shell is embedded with multiple mechanical strain membranes arranged in a ring, and strain gauges are provided on the mechanical strain membranes.

[0010] Preferably, the rack assembly includes a vertical rod that is slidably connected to the side wall of the housing, and a limiting hole is provided on the upper side wall of the vertical rod. The lower side wall of the vertical rod is provided with a plurality of trapezoidal grooves, and the inner wall of the trapezoidal grooves is rotatably connected with a locking tooth that matches the gear.

[0011] Preferably, the side wall of the outer casing is provided with a clearance groove, and the return spring is located in the clearance groove; the inner wall of the portal frame is provided with a vertically arranged sliding groove; and the side wall of the limiting rod is fixedly connected with a slider that matches the sliding groove.

[0012] Preferably, the sidewalls of the drive rod and the rack assembly near the return spring are both provided with vertically arranged strip grooves, and a limiting strip matching the slide groove is fixedly connected in the strip groove.

[0013] Preferably, the frame is polygonal in shape, and the outer side wall of the frame is fixedly connected with a sealing gasket that is interference-fitted with the inner wall of the outer shell.

[0014] Preferably, the length of the limiting rod is greater than the thickness of the driving rod and the vertical rod, and the length of the limiting rod is less than the sum of the thicknesses of the driving rod and the vertical rod.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] This invention, by setting up a strain gauge assembly in conjunction with an electric push rod and a drive rod, uses the drive rod to drive the rack assembly to move, thereby switching the strain gauge assembly in conjunction with the gear, thus changing the detection range of the electronic control assembly, expanding the single detection range into multiple independent detection intervals with high detection accuracy of pressure, and automatically switching when the pressure exceeds the detection range, can ensure both pressure detection accuracy and a large detection range of the pressure transmitter.

[0017] In addition, by setting a reset spring in conjunction with a limit rod and an electromagnet, the position of the limit rod can be adjusted by the electromagnet, so that the drive rod can drive different rack assemblies to move, thereby controlling the shaft to run clockwise or counterclockwise, effectively controlling the switching direction of the strain components, and the structure is simple, effectively controlling the equipment cost.

[0018] This invention, by setting up a strain assembly consisting of a frame and multiple mechanical strain substrates with different elastic coefficients, allows different mechanical strain substrates to be aligned with the pressure source after the shaft rotates, thereby achieving switching of the detection range, and, in conjunction with strain gauges, accurately detecting the pressure in different ranges.

[0019] This invention, by setting a strain assembly consisting of a circular shell and partitions, sets different pre-pressures within multiple partitions to offset part of the detection pressure, thereby achieving switching of the detection range. It can use mechanical strain membranes with completely identical materials and elastic coefficients to achieve accurate detection of pressure in different ranges.

[0020] This invention, by setting a trapezoidal groove and a rotating connecting tooth, allows a single rack assembly to drive the gear to rotate in a fixed direction by a fixed angle when the electro-hydraulic actuator drives the drive rod to reciprocate. This enables precise control of the switching of the strain gauge components. Furthermore, the use of a mechanical structure for control results in higher stability, lower equipment cost, and greater durability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of an explosion-proof pressure transmitter for a pressure sensor proposed in this invention.

[0022] Figure 2 This is a schematic diagram of the first embodiment of an explosion-proof pressure transmitter for a pressure sensor proposed in this invention;

[0023] Figure 3 This is a partial structural schematic diagram of an explosion-proof pressure transmitter for a pressure sensor proposed in this invention;

[0024] Figure 4 for Figure 1 Enlarged structural diagram at point A;

[0025] Figure 5 for Figure 2 Enlarged structural diagram at point B;

[0026] Figure 6 for Figure 3 Enlarged structural diagram at point C;

[0027] Figure 7 for Figure 3 Enlarged structural diagram at point D;

[0028] Figure 8 This is a schematic diagram of the second embodiment of an explosion-proof pressure transmitter for a pressure sensor proposed in this invention.

[0029] In the diagram: 1. Outer shell; 2. Support frame; 3. Electrical control assembly; 4. Shaft; 5. Strain assembly; 51. Frame; 52. Mechanical strain matrix; 53. Circular shell; 54. Partition plate; 55. Mechanical strain membrane; 6. Conductive sheet; 7. Gear; 8. Electro-hydraulic actuator; 9. Drive rod; 10. Through hole; 11. Rack assembly; 111. Vertical rod; 112. Trapezoidal groove; 113. Clamping tooth; 12. Limiting hole; 13. Return spring; 14. U-shaped frame; 15. Limiting rod; 16. Electromagnet; 17. Slide groove; 18. Slider; 19. Limiting strip; 20. Sealing gasket. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Example 1

[0033] Reference Figure 1-7An explosion-proof pressure transmitter for a pressure sensor includes a housing 1, a support frame 2 fixedly connected to the upper end of the housing 1, an electrical control component 3 mounted on the support frame 2, the electrical control component 3 being the same as the electrical control equipment on a transmitter in the prior art, including a signal processor, a display screen, a communication module, etc., and additionally a relay for controlling an electromagnet 16 and an electro-hydraulic actuator 8, the operation of which is controlled by the signal processor, and a switching component mounted on the housing 1;

[0034] The switching assembly includes a shaft 4 rotatably connected to the inner wall of the outer casing 1. A strain gauge 5 is mounted on the shaft 4. A conductive sheet 6 is mounted on the inner wall of the outer casing 1. A metal sheet abutting against the conductive sheet 6 is mounted on the strain gauge 5. One end of the shaft 4 passes through the outer casing 1 and extends to the outside of the outer casing 1. A gear 7 is fixedly sleeved on the shaft 4 located outside the outer casing 1. An electro-hydraulic actuator 8 is fixedly connected to the side wall of the outer casing 1. The electro-hydraulic actuator 8 has a larger thrust and a more stable stroke. Compared with motor drive, the rack assembly 11 combined with the gear 7 can more accurately and effectively control the rotation angle. At the same time, the mechanical structure is simpler and more stable, and the service life is longer. A drive rod 9 is fixedly connected to the lower end of the electro-hydraulic actuator 8. A through hole 10 is opened on the side wall of the drive rod 9. A symmetrically arranged rack assembly 11 is fixedly and slidably connected to the side wall of the outer casing 1 near the drive rod 9. The rack assembly 11 is located on both sides of the gear 7 and is initially in a certain state. In the normal state, the rack assembly 11 does not contact the gear 7. On the other hand, the rack assembly 11 and the outer shell 1 have a frictional force greater than the weight of the rack assembly 11, so that the rack assembly 11 is stationary when the drive rod 9 does not drive the rack assembly 11. The rack assembly 11 is provided with a limiting hole 12 that matches the through hole 10. A return spring 13 is fixedly connected to the side wall of the outer shell 1, and a portal frame 14 is fixedly connected to the end of the return spring 13 away from the outer shell 1. A limiting rod 15 is slidably connected inside the portal frame 14. The limiting rod 15 is set through the through hole 10 and the limiting hole 12. An electromagnet 16 is fixedly connected to the side wall of the outer shell 1 away from the return spring 13. The limiting rod 15 is made of magnetic metal material that cooperates with the electromagnet 16. The electromagnet 16 and the electro-hydraulic push rod 8 are both electrically connected to the electronic control component 3. The switching component can switch the strain component 5 when the pressure change exceeds the detection range to ensure high precision and wide range detection.

[0035] The strain assembly 5 includes a frame 51, with metal sheets located on the side wall of the frame 51. The frame 51 is fixedly connected to the shaft 4 via a connecting rod. Multiple mechanical strain substrates 52 with different elastic coefficients are embedded in the polygonal frame 51. Strain gauges are installed on the mechanical strain substrates 52. This design allows for the detection of pressure in different ranges by using mechanical strain substrates 52 with different elastic coefficients in conjunction with strain gauges. It can also ensure relatively accurate detection results in any range. Furthermore, based on the range of pressure changes in the pipeline, a mechanical strain substrate 52 with higher strength can be selected in the range of higher pressure.

[0036] Furthermore, the rack assembly 11 includes a vertical rod 111, which is slidably connected to the side wall of the housing 1. A limiting hole 12 is located on the upper side wall of the vertical rod 111. The lower side wall of the vertical rod 111 is provided with multiple trapezoidal grooves 112, and the inner wall of the trapezoidal grooves 112 is rotatably connected to a locking tooth 113 that matches the gear 7. In this design, the trapezoidal grooves 112 are used to accommodate the locked tooth 113 after rotation. This allows the locked tooth 113 to prevent the gear 7 from rotating when the vertical rod 111 moves downward. When the vertical rod 111 moves upward, the lower end of the locked tooth 113 abuts against the inner wall of the trapezoidal groove 112, thereby driving the gear 7 to rotate.

[0037] Furthermore, the side wall of the outer casing 1 is provided with a clearance groove, and the return spring 13 is located in the clearance groove. The inner wall of the portal frame 14 is provided with a vertically arranged sliding groove 17. The side wall of the limiting rod 15 is fixedly connected with a slider 18 that matches the sliding groove 17. This design ensures that the portal frame 14 can drive the limiting rod 15 to move in the horizontal direction, thereby cooperating with the electromagnet 16 to realize the reciprocating motion of the limiting rod 15, and preventing the limiting rod 15 from disengaging from the portal frame 14, which would prevent the limiting rod 15 from resetting under the action of the return spring 13.

[0038] Furthermore, both the drive rod 9 and the rack assembly 11 near the return spring 13 have vertically arranged strip grooves on their side walls, and a limiting strip 19 matching the slide groove 17 is fixedly connected inside the strip groove. This arrangement uses the strip groove to make way for the portal frame 14, thereby avoiding interference between the portal frame 14 and the limiting rod 15 when the drive rod 9 drives the rack assembly 11. The limiting strip 19 is used to limit the portal frame 14. When the limit rod 15 is disengaged from the portal frame 14, the portal frame 14 will not move under the action of the return spring 13, thereby preventing the portal frame 14 from disengaging from the limit rod 15 after the detection interval is switched. Only one vertical rod 111 is provided with a strip groove and a limit bar 19. The length of the vertical rod 111 with the strip groove and the limit bar 19 is greater than that of the vertical rod 111 without the strip groove and the limit bar 19. The vertical rod 111 with the strip groove and the limit bar 19 is located close to the return spring 13.

[0039] Furthermore, the frame 51 is polygonal in shape, and a sealing gasket 20 that is interference-fitted with the inner wall of the housing 1 is fixedly connected to the outer side wall of the frame 51. This design is used to improve the sealing performance of the strain gauge assembly 5, thereby preventing the pressure medium from completely immersing into the interior of the housing 1 and avoiding deviations in the detection structure.

[0040] Furthermore, the length of the limiting rod 15 is greater than the thickness of the driving rod 9 and the vertical rod 111, and the length of the limiting rod 15 is less than the sum of the thicknesses of the driving rod 9 and the vertical rod 111.

[0041] In this invention, when in use, the user connects the outer shell 1 to the pressure pipeline or container using methods such as flanges or welding, according to actual needs. Then, the deformed mechanical strain substrate 52, in conjunction with strain gauges and the electronic control component 3, detects the pressure. If the pressure in the pipeline or container is too high, exceeding the deformation range of the mechanical strain substrate 52, or too low, making it difficult to deform the mechanical strain substrate 52, or if the deformation amplitude is too small, the electronic control component 3 controls the electro-hydraulic actuator 8 to perform one extension / retraction stroke. At this time, the drive rod 9 reciprocates up and down once. During the reciprocating motion of the drive rod 9, the limiting rod 15 drives the... One rack assembly 11 moves up and down once, and a single rack assembly 11 can only drive the gear 7 to rotate in a single direction by a fixed angle. This allows the strain component 5 located in the housing to rotate by a fixed angle under the drive of the shaft 4, thereby achieving the switching of the mechanical strain substrate 52 and changing the detection range. This can expand the pressure detection range and improve the detection accuracy, allowing for better and more precise monitoring of pipelines and containers with large pressure changes. When adjusting the strain component 5 in the opposite direction, the electromagnet 16 is controlled to run, and the electromagnet 16 drives the limit rod 15 to move into another rack assembly 11.

[0042] Example 2

[0043] Reference Figure 8 The strain assembly 5 includes a circular housing 53 fixedly connected to the shaft 4. A metal sheet is located on the side wall of the circular housing 53. Multiple partitions 54 are fixedly connected to the inner wall of the circular housing 53. The partitions 54 divide the circular housing 53 into multiple fan-shaped cavities. Pre-pressure media with different pressure values ​​are provided in the fan-shaped cavities. Multiple mechanical strain membranes 55 are embedded in the side wall of the circular housing 53 and arranged in a ring. Strain gauges are provided on the mechanical strain membranes 55.

[0044] The difference between this design and Embodiment 1 is that by setting a pre-pressure medium with different pressure values ​​to offset part of the pressure, it is possible to detect pressure in different ranges. When using a mechanical strain substrate 52 with different elastic coefficients to divide the range, the detection range is larger. However, since the elasticity of the mechanical strain substrate 52 changes linearly, the detection accuracy will still decrease when the detection pressure is large. When using a pre-pressure medium to offset part of the pressure, it can ensure high accuracy in any range, although the detection range is relatively small. It is worth mentioning that the settings of Embodiment 1 and Embodiment 2 do not conflict. In cases where the accuracy requirements are extremely high, such as scientific research and transportation of hazardous chemicals, the explosion-proof pressure transmitter for this pressure sensor can be made by combining the two schemes of Embodiment 1 and Embodiment 2.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An explosion-proof pressure transmitter for a pressure sensor, comprising a housing (1), characterized in that, The upper end of the outer shell (1) is fixedly connected to a support frame (2), an electrical control component (3) is provided on the support frame (2), and a switching component is provided on the outer shell (1); The switching assembly includes a shaft (4) rotatably connected to the inner wall of the housing (1). Multiple strain components (5) are mounted on the shaft (4). A conductive sheet (6) is mounted on the inner wall of the housing (1). One end of the shaft (4) passes through the housing (1) and extends to the outside of the housing (1). A gear (7) is fixedly mounted on the shaft (4) located outside the housing (1). An electro-hydraulic actuator (8) is fixedly connected to the side wall of the housing (1), and a drive rod (9) is fixedly connected to the lower end of the electro-hydraulic actuator (8). A through hole (10) is opened on the side wall of the drive rod (9). A sliding connection is fixedly made to the side wall of the housing (1) near the drive rod (9). A rack assembly (11) is symmetrically arranged, and a limiting hole (12) matching the through hole (10) is provided on the rack assembly (11). A return spring (13) is fixedly connected to the side wall of the outer shell (1), and a portal frame (14) is fixedly connected to the end of the return spring (13) away from the outer shell (1). A limiting rod (15) is slidably connected inside the portal frame (14). The limiting rod (15) is provided through the through hole (10) and the limiting hole (12). An electromagnet (16) is fixedly connected to the side wall of the outer shell (1) away from the return spring (13). The electromagnet (16) and the electro-hydraulic push rod (8) are both electrically connected to the electronic control assembly (3). The rack assembly (11) includes a vertical rod (111), which is slidably connected to the side wall of the outer shell (1), and a limiting hole (12) is provided on the upper side wall of the vertical rod (111). The lower side wall of the vertical rod (111) is provided with a plurality of trapezoidal grooves (112), and the inner wall of the trapezoidal grooves (112) is rotatably connected with a locking tooth (113) that matches the gear (7). The side wall of the outer shell (1) is provided with a clearance groove, and the reset spring (13) is located in the clearance groove. The inner wall of the portal frame (14) is provided with a vertically arranged sliding groove (17), and the side wall of the limiting rod (15) is fixedly connected with a slider (18) that matches the sliding groove (17). The drive rod (9) and the rack assembly (11) near the return spring (13) are both provided with vertically arranged strip grooves on their side walls, and a limiting strip (19) matching the slide groove (17) is fixedly connected in the strip groove. The length of the limiting rod (15) is greater than the thickness of the driving rod (9) and the vertical rod (111), and the length of the limiting rod (15) is less than the sum of the thicknesses of the driving rod (9) and the vertical rod (111).

2. The explosion-proof pressure transmitter for a pressure sensor according to claim 1, characterized in that, The strain assembly (5) includes a frame (51), which is fixedly connected to the shaft (4) by a connecting rod. Multiple mechanical strain substrates (52) with different elastic coefficients are embedded in the frame (51), and strain gauges are provided on the mechanical strain substrates (52).

3. The explosion-proof pressure transmitter for a pressure sensor according to claim 1, characterized in that, The strain assembly (5) includes a circular shell (53) fixedly connected to the shaft (4). The inner wall of the circular shell (53) is fixedly connected to multiple partitions (54), and the side wall of the circular shell (53) is embedded with multiple mechanical strain membranes (55) arranged in a ring, and strain gauges are provided on the mechanical strain membranes (55).

4. The explosion-proof pressure transmitter for a pressure sensor according to claim 2, characterized in that, The frame (51) is polygonal in shape, and the outer side wall of the frame (51) is fixedly connected with a sealing gasket (20) that is interference-fitted with the inner wall of the outer shell (1).

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