A wedge-shaped differential pressure flowmeter

Abstract

The present invention discloses a wedge-shaped pressure differential flowmeter, which belongs to the technical field of flowmeter equipment. It comprises: a tube body, a pressure differential device and a wedge-shaped mechanism. The wedge-shaped mechanism comprises two baffles, an adjustment assembly and two sets of blocking components. Sensing mechanisms are provided on both sides of the tube body. A socket is provided on the upper side of the tube body. The bottom ends of the two baffles are in V-shaped rolling contact. The sensing mechanism comprises a turbine, a gear ring, a cylinder, a pressure sensing device, a first impeller, a first compression spring, a first gear and a main shaft. The pressure taking assembly is arranged in the upper side wall inside the tube body and is connected to the main shaft through a linkage component. The present invention effectively solves the problem that the wedge-shaped structure cannot adjust itself according to the flow state of the fluid, thereby affecting the accuracy of the measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of flow meter equipment, in particular to a wedge-shaped differential pressure flow meter. Background Art

[0002] The wedge flowmeter is a throttling pressure differential flow measuring instrument suitable for measuring volume flow and mass flow in the petroleum, chemical and other industries. The throttling element of the wedge flowmeter is a V-shaped wedge block. Its principle is to measure the pressure difference between the upstream and downstream sides of the throttling element, and convert the measured pressure difference into flow according to the Bernoulli equation and the continuity equation.

[0003] Existing wedge flowmeters are concentrated, such as the utility model patent with announcement number CN205561935U which discloses a wedge flowmeter, the utility model patent with announcement number CN211954280U which discloses an adjustable wedge flowmeter, and the utility model patent with announcement number CN221198547U which discloses a variable flow wedge flowmeter. In the above wedge flowmeters, manual adjustment is required when adjusting the wedge structure, and the wedge structure cannot adjust itself according to the flow state of the fluid, thereby affecting the accuracy of the measurement. Summary of the Invention

[0004] The purpose of the present invention is to provide a wedge-shaped differential pressure flowmeter to solve the problem raised in the above background technology that manual adjustment is required when adjusting the wedge structure, and the wedge structure cannot adjust itself according to the flow state of the fluid, thereby affecting the accuracy of the measurement.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A wedge-shaped differential pressure flowmeter comprises: a tube body, a differential pressure device, and a wedge-shaped mechanism, wherein the wedge-shaped mechanism is arranged on the upper side of the middle portion of the tube body, the differential pressure device is fixedly mounted on the side of the tube body, pressure taking assemblies are provided on both sides of the differential pressure device, and flanges are fixedly mounted on both ends of the tube body for connecting to the pipeline;

[0007] The wedge-shaped mechanism includes two baffles, an adjustment assembly, and two sets of blocking components. Sensing mechanisms are provided on both sides of the tube body. The adjustment assembly is connected to the sensing mechanism at the input end via a transmission component. A socket is provided on the upper side of the tube body. The bottoms of the two baffles are rotatably mounted on the inner wall of the tube body via a support rod and are both located in the socket. The bottom ends of the two baffles are in V-shaped rolling contact, and the top ends are connected to the adjustment assembly.

[0008] The sensing mechanism includes a turbine, a ring gear, a cylinder, a pressure sensing device, a first impeller, a first compression spring, a first gear and a main shaft. The cylinder is vertically fixed on the upper side of the tube body through a bracket, the pressure sensing device is fixedly installed on the top of the cylinder body, the turbine is rotatably embedded in the inner wall of the tube body, the ring gear is fixedly installed on the side wall of the turbine, the first gear is fixedly sleeved on the bottom end of the main shaft and meshed with the ring gear, the first impeller is vertically slidably sleeved on the main shaft, a support ring is rotatably embedded on the upper side of the first impeller, the first compression spring is vertically sleeved on the upper side of the main shaft, and the upper and lower ends are respectively fixedly connected to the sensing end on the bottom side of the pressure sensing device and the upper side of the support ring;

[0009] The pressure taking assembly is arranged in the upper side wall inside the tube body and is connected to the main shaft through a linkage component.

[0010] As a preferred technical solution of the present invention, a shell is fixedly installed on the upper side of the tube body, the wedge-shaped mechanism is arranged in the shell, and the adjusting assembly includes a first screw, a truss, two slides, two sliding rods and two connecting plates. The truss is vertically fixed on the upper side of the tube body, the two slides are symmetrically arranged vertically, and the top ends are slidably embedded in the truss, the first screw is horizontally rotated and sleeved in the truss, the two slides are threadedly sleeved on the first screw, and the end of the first screw close to the input end passes through the shell and penetrates into the cylinder, the two connecting plates are respectively fixed on the top of the two baffles, and the two sliding rods are respectively horizontally and radially fixedly sleeved in the two connecting plates, and are respectively in sliding contact with the inside of the two slides.

[0011] As a preferred technical solution of the present invention, the transmission component is arranged on the bottom side of the first impeller located at the input end, and includes a retaining ring, a first rack and a second gear. The retaining ring is rotatably sleeved on the bottom of the first impeller, and a clamping plate is horizontally fixedly installed on the inner wall of the cylinder located at the input end. The first rack is vertically slidably sleeved in the clamping plate, and the top end is fixedly connected to the bottom side of the retaining ring. The second gear is fixedly sleeved on the end of the first screw and is meshed with the first rack.

[0012] As a preferred technical solution of the present invention, the sealing component includes a sealing plate and a magnetic block. A sliding cavity is horizontally opened inside the top wall of the tube body. The sealing plate is horizontally sealed and slidably sleeved in the sliding cavity. The magnetic block is fixedly installed on the bottom side of the baffle. The ends of the two sealing plates that are close to each other are respectively adsorbed by two magnetic blocks.

[0013] As an optimal technical solution of the present invention, the pressure taking assembly includes a connecting pipe, a hose and a pipe head. The connecting pipe is fixedly sleeved in the pipe body, the pipe head is vertically arranged and connected to the linkage component, and the top end of the pipe head is fixedly connected to the connecting pipe input end through the hose.

[0014] The second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear is engaged with the first gear and the second gear.

[0015] As a preferred technical solution of the present invention, two pressure-sensitive display devices are fixedly installed on the outside of the tube body, and are electrically connected to the two pressure sensing devices respectively, for feeding back pressure data of the two pressure sensing devices.

[0016] Compared with the prior art, the present invention provides a wedge-shaped differential pressure flowmeter, which has the following beneficial effects:

[0017] (1) With the cooperation of the sensing mechanism and the transmission components, the opening angle of the wedge-shaped structure formed by the two baffles can be automatically adjusted according to the flow rate of the fluid. It can be adjusted in real time as the flow rate changes, which can fully ensure the accuracy of measurement;

[0018] (2) The pressure values ​​of the two pressure sensing devices can indirectly reflect the changes in the pressure difference of the fluid. By comparing the measurement results of the pressure difference device, it can be judged whether the pressure difference device is in a normal working state, which serves as a reference;

[0019] (3) With the cooperation of the linkage components, the distance between the tube head and the wedge structure is adjusted according to the opening angle of the wedge structure to ensure that the sampling point is in the effective sampling area, avoid the influence of eddy current instability factors, and further ensure the accuracy of measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the three-dimensional structure of a wedge-shaped differential pressure flowmeter proposed by the present invention;

[0021] Figure 2 This is a schematic diagram of a partial cross-sectional structure of a wedge-shaped differential pressure flowmeter proposed by the present invention;

[0022] Figure 3 for Figure 2 A magnified view of the structure at point A;

[0023] Figure 4 for Figure 2 A magnified view of the structure at point B in FIG;

[0024] Figure 5 for Figure 2 Enlarged view of the structure at point C in .

[0025] In the figure: 1, tube body; 101, socket; 2, pressure differential device; 3, flange; 4, baffle; 401, support rod; 5, shell; 6, turbine; 7, ring gear; 8, cylinder; 801, air hole; 9, pressure sensor; 10, first impeller; 11, first compression spring; 12, first gear; 13, main shaft; 14, bracket; 15, support ring; 16, first screw; 17, truss; 18, slide; 19, slide rod; 20, Connecting plate; 21. Retaining ring; 22. First rack; 23. Second gear; 24. Pressure-sensitive display device; 25. Retaining plate; 26. Closing plate; 27. Magnetic block; 28. Sliding cavity; 29. ​​Connecting tube; 30. Hose; 31. Tube head; 32. Second screw; 33. Sliding block; 34. Second impeller; 35. Third gear; 36. Second rack; 37. Cross plate; 38. Pressing ring; 39. Pulling ring; 40. Second compression spring; 41. Slide groove. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, what is described is only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] See Figure 1-5 A wedge-shaped differential pressure flowmeter comprises: a tube body 1, a differential pressure device 2 and a wedge-shaped mechanism, wherein the wedge-shaped mechanism is arranged on the upper middle side of the tube body 1, the differential pressure device 2 is fixedly mounted on the side of the tube body 1, pressure taking assemblies are provided on both sides of the differential pressure device 2, and flanges 3 are fixedly mounted on both ends of the tube body 1 for connecting to the pipeline;

[0028] The wedge-shaped mechanism includes two baffles 4, an adjustment assembly, and two sets of blocking components. Sensing mechanisms are provided on both sides of the tube body 1. The adjustment assembly is connected to the sensing mechanism at the input end via a transmission component. A socket 101 is provided on the upper side of the tube body 1. The bottoms of the two baffles 4 are rotatably mounted on the inner wall of the tube body 1 via a support rod 401 and are both located within the socket 101. The bottom ends of the two baffles 4 are in V-shaped rolling contact, and the top ends are connected to the adjustment assembly.

[0029] The sensing mechanism includes a turbine 6, a ring gear 7, a cylinder 8, a pressure sensing device 9, a first impeller 10, a first compression spring 11, a first gear 12 and a main shaft 13. The cylinder 8 is vertically fixedly mounted on the upper side of the tube body 1 through a bracket 14. The pressure sensing device 9 is fixedly mounted on the top of the cylinder 8. The turbine 6 is rotatably embedded in the inner wall of the tube body 1. The ring gear 7 is fixedly mounted on the side wall of the turbine 6. The first gear 12 is fixedly sleeved on the bottom end of the main shaft 13 and meshed with the ring gear 7. The first impeller 10 is vertically slidably sleeved on the main shaft 13. A support ring 15 is rotatably embedded on the upper side of the first impeller 10. The first compression spring 11 is vertically sleeved on the upper side of the main shaft 13, and the upper and lower ends are respectively fixedly connected to the sensing end on the bottom side of the pressure sensing device 9 and the upper side of the support ring 15;

[0030] The top and rear sides of the cylinder 8 are each provided with air holes 801;

[0031] The pressure taking assembly is arranged in the upper side wall of the tube body 1 and is connected to the main shaft 13 through a linkage component;

[0032] Two pressure-sensitive display devices 24 are fixedly installed on the outside of the tube body 1 , and are electrically connected to the two pressure sensing devices 9 respectively, for feeding back pressure data of the two pressure sensing devices 9 .

[0033] The pressure sensing device 9 and the pressure display device 24, as well as the circuit connection relationship between the two, are all related to the prior art and will not be described in detail here.

[0034] A shell 5 is fixedly installed on the upper side of the tube body 1, and a wedge-shaped mechanism is arranged in the shell 5. The adjusting assembly includes a first screw 16, a truss 17, two slides 18, two slide rods 19 and two connecting plates 20. The truss 17 is vertically fixed on the upper side of the tube body 1, and the two slides 18 are symmetrically arranged vertically, and the top ends are slidably embedded in the truss 17. The first screw 16 is horizontally rotated and sleeved in the truss 17. The two slides 18 are threadedly sleeved on the first screw 16. The end of the first screw 16 close to the input end passes through the shell 5 and penetrates into the cylinder 8. The two connecting plates 20 are respectively fixedly installed on the top of the two baffles 4. The two slide rods 19 are respectively horizontally and radially fixedly sleeved in the two connecting plates 20, and are respectively in sliding contact with the inside of the two slides 18.

[0035] The transmission component is arranged on the bottom side of the first impeller 10 at the input end, and includes a retaining ring 21, a first rack 22 and a second gear 23. The retaining ring 21 is rotatably sleeved on the bottom of the first impeller 10, and a clamping plate 25 is horizontally fixedly installed on the inner wall of the cylinder 8 at the input end. The first rack 22 is vertically slidably sleeved in the clamping plate 25, and the top end is fixedly connected to the bottom side of the retaining ring 21. The second gear 23 is fixedly sleeved on the end of the first screw 16 and meshed with the first rack 22.

[0036] The sealing components include a sealing plate 26 and a magnetic block 27. A sliding cavity 28 is horizontally opened inside the top wall of the tube body 1. The sealing plate 26 is horizontally sealed and slidably sleeved in the sliding cavity 28. The magnetic block 27 is fixedly installed on the bottom side of the baffle 4. The ends of the two sealing plates 26 that are close to each other are respectively adsorbed by the two magnetic blocks 27. During the deflection process of the baffle 4, the two sealing plates 26 are always attracted by the magnetic block 27. The two sealing plates 26 and the two baffles 4 seal the socket 101.

[0037] The pressure taking assembly includes a connecting pipe 29, a hose 30 and a pipe head 31. The connecting pipe 29 is fixedly sleeved in the pipe body 1, the pipe head 31 is vertically arranged and connected to the linkage component, and the top end of the pipe head 31 is fixedly connected to the input end of the connecting pipe 29 through the hose 30.

[0038] The linkage components include a second screw 32, a slider 33, a second impeller 34, a third gear 35, a second rack 36, a cross plate 37, a pressure ring 38, a pull ring 39 and a second compression spring 40. A slide groove 41 is symmetrically provided on the bottom side of the top wall of the tube body 1. The slider 33 is horizontally slidably embedded in the slide groove 41. The second screw 32 is horizontally rotatably sleeved on the top of the tube body 1 and passes through the slide groove 41. The third gear 35 is fixedly sleeved on the end of the second screw 32. The slider 33 is threadedly sleeved on the second screw 32. The pipe head 31 and the input end of the hose 30 are connected. They are all fixedly sleeved in the slider 33 and fixedly connected and conducted. The second impeller 34 is vertically slidably sleeved on the main shaft 13. The cross plate 37 is horizontally fixedly installed on the inner wall of the cylinder 8. The pressure ring 38 and the pull ring 39 are rotatably sleeved on the upper and lower sides of the second impeller 34 respectively. The second compression spring 40 is vertically sleeved on the main shaft 13, and the upper and lower ends are fixedly connected to the bottom of the cross plate 37 and the upper side of the pressure ring 38 respectively. The second rack 36 is vertically slidably sleeved in the top wall of the tube body 1, and the top is fixedly connected to the pull ring 39. The third gear 35 is meshed with the second rack 36.

[0039] The opening angle of the wedge mechanism in a wedge flowmeter directly affects its performance and application scenarios. The specific impacts are as follows:

[0040] Small opening angle: The wedge is sharp, and the fluid contracts significantly when flowing through it, generating a large differential pressure. It is more sensitive to low flow rate fluids and is suitable for low flow measurement;

[0041] Large opening angle: The fluid contracts smoothly and the differential pressure is small. It is suitable for high flow rate scenarios, but the sensitivity may be insufficient at low flow rates.

[0042] When using this device for metering, the two ends of the pipe body 1 are connected to the conveying pipeline through the flange 3. When the fluid flows through the pipe body 1, a pressure difference is generated under the interference of the wedge mechanism, so that the pressure difference device 2 measures its flow.

[0043] During the fluid flow process, the turbine 6 is impacted, and the turbine 6 drives the ring gear 7 to rotate, and the ring gear 7 drives the first gear 12 to rotate, and the first gear 12 drives the main shaft 13 to rotate, and the main shaft 13 mobilizes the first impeller 10 to rotate. The rotation of the first impeller 10 generates lift to move upward, compressing the first compression spring 11, and at the same time driving the first rack 22 to move upward, and the first rack 22 drives the second gear 23 to drive the first screw 16 to rotate.

[0044] Under the interference of the first compression spring 11 , when the lift of the first impeller 10 is balanced with the elastic force of the first compression spring 11 , the first impeller 10 is maintained at a certain height, so that the first screw 16 rotates a certain number of turns.

[0045] When the first screw 16 rotates, it drives the two slides 18 away from each other, thereby causing the two slides 19 to move away from each other and move downward. Under the support of the two support rods 401, the two baffles 4 deflect outward, thereby increasing the opening angle of the wedge-shaped mechanism to adapt to the metering of fluids with higher flow rates. When the flow rate of the fluid decreases, the speed of the turbine 6 decreases, thereby causing the speed of the main shaft 13 to decrease, reducing the lift, and the first impeller 10 moves downward, driving the first rack 22 to move downward, causing the first screw 16 to rotate in the opposite direction, causing the two slides 18 to approach each other, thereby causing the two baffles 4 to deflect upward, so that the opening angle of the two baffles 4 becomes smaller, to adapt to the flow conditions of fluids with low flow rates.

[0046] With the cooperation of the sensing mechanism and the transmission components, the opening angle of the wedge-shaped structure formed by the two baffles 4 can be automatically adjusted according to the flow rate of the fluid, and can be adjusted in real time as the flow rate changes, thereby more fully ensuring the accuracy of measurement.

[0047] When the first impeller 10 compresses the first compression spring 11, the elastic force of the first compression spring 11 acts on the pressure sensing device 9, so that the torque of the turbine 6 is converted into pressure. When the fluid flow rate changes, the torque of the turbine 6 changes synchronously, thereby changing the pressure value of the pressure sensing device 9. Since the fluid speed changes after passing through the wedge mechanism, the torques of the two turbines 6 are different. The pressure values ​​of the two pressure sensing devices 9 can indirectly reflect the change in the pressure difference of the fluid. By comparing the measurement results of the pressure difference device 2, it can be determined whether the pressure difference device 2 is in a normal working state.

[0048] During the rotation of the main shaft 13, it synchronously drives the second impeller 34 to rotate. The second impeller 34 rotates synchronously, compressing the second compression spring 40, and obtaining different aerodynamic lift according to the torque of the turbine 6, thereby moving to different heights, driving the second rack 36 to rise and fall. The rise and fall of the second rack 36 drives the third gear 35 to drive the second screw 32 to rotate, and the second screw 32 drives the slider 33 to move. The slider 33 drives the tube head 31 to move for sampling, and transmits the sample to the pressure difference device 2 through the hose 30. According to the different opening angles of the wedge structure, the distance between the tube head 31 and the wedge mechanism is adjusted. When the flow rate increases, the opening angle increases, and the slider 33 moves away from the baffle 4. When the flow rate decreases, the opening angle decreases, and the slider 33 approaches the baffle 4 to ensure that the sampling point is in the effective sampling area, avoid the influence of eddy current instability factors, and further ensure the accuracy of measurement.

[0049] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A wedge-shaped differential pressure flowmeter, comprising: The pipe body, the pressure differential device and the wedge mechanism are provided. The wedge mechanism is provided on the upper side of the middle part of the pipe body. The pressure differential device is fixedly installed on the side of the pipe body. Pressure taking components are provided on both sides of the pressure differential device. The invention is characterized in that: the wedge-shaped mechanism includes two baffles, an adjustment component and two sets of blocking components, a sensing mechanism is provided on both sides of the tube body, the adjustment component is connected to the sensing mechanism at the input end via a transmission component, a socket is provided on the upper side of the tube body, the bottoms of the two baffles are rotatably mounted on the inner wall of the tube body through a support rod and are both located in the socket, the bottom ends of the two baffles are in V-shaped rolling contact, and the top ends are connected to the adjustment component; The sensing mechanism includes a turbine, a ring gear, a cylinder, a pressure sensing device, a first impeller, a first compression spring, a first gear and a main shaft. The cylinder is vertically fixed on the upper side of the tube body through a bracket, the pressure sensing device is fixedly installed on the top of the cylinder body, the turbine is rotatably embedded in the inner wall of the tube body, the ring gear is fixedly installed on the side wall of the turbine, the first gear is fixedly sleeved on the bottom end of the main shaft and meshed with the ring gear, the first impeller is vertically slidably sleeved on the main shaft, a support ring is rotatably embedded on the upper side of the first impeller, the first compression spring is vertically sleeved on the upper side of the main shaft, and the upper and lower ends are respectively fixedly connected to the sensing end on the bottom side of the pressure sensing device and the upper side of the support ring; The pressure taking assembly is arranged in the upper side wall inside the tube body and is connected to the main shaft through a linkage component; A sealing shell is fixedly installed on the upper side of the tube body, and a wedge-shaped mechanism is arranged in the sealing shell. The adjustment assembly includes a first screw, a truss, two slides, two sliding rods and two connecting plates. The truss is vertically fixed on the upper side of the tube body, and the two slides are symmetrically arranged vertically, and the top ends are both slidably embedded in the truss. The first screw is horizontally rotated and sleeved in the truss. The two slides are both threadedly sleeved on the first screw. The end of the first screw near the input end passes through the sealing shell and penetrates into the cylinder. The two connecting plates are respectively fixed on the tops of the two baffles. The two sliding rods are respectively fixedly sleeved in the two connecting plates in a horizontal and radial manner and are in sliding contact with the inside of the two slides. The transmission component is arranged on the bottom side of the first impeller at the input end, and includes a retaining ring, a first rack and a second gear. The retaining ring is rotatably sleeved on the bottom of the first impeller, and a clamping plate is horizontally fixedly installed on the inner wall of the cylinder at the input end. The first rack is vertically slidably sleeved in the clamping plate, and the top end is fixedly connected to the bottom side of the retaining ring. The second gear is fixedly sleeved on the end of the first screw and meshed with the first rack.

2. A wedge-shaped differential pressure flowmeter according to claim 1, characterized in that: The sealing components include a sealing plate and a magnetic block. A sliding cavity is horizontally opened inside the top wall of the tube body. The sealing plate is horizontally sealed and slidably sleeved in the sliding cavity. The magnetic block is fixedly installed on the bottom side of the baffle. The ends of the two sealing plates that are close to each other are respectively adsorbed by the two magnetic blocks.

3. A wedge-shaped differential pressure flowmeter according to claim 1, characterized in that: The pressure taking assembly includes a connecting pipe, a hose and a pipe head. The connecting pipe is fixedly sleeved in the pipe body, the pipe head is vertically arranged and connected to the linkage component, and the top of the pipe head is fixedly connected to the connecting pipe input end through the hose.

4. A wedge-shaped differential pressure flowmeter according to claim 3, characterized in that: The linkage parts include a second screw, a slider, a second impeller, a third gear, a second rack, a cross plate, a pressure ring, a pull ring and a second compression spring. A slide groove is horizontally symmetrically opened on the bottom side of the top wall of the tube body, the slider slides horizontally and is embedded in the slide groove, the second screw is horizontally rotatably sleeved on the top of the tube body and passes through the slide groove, the third gear is fixedly sleeved on the end of the second screw, the slider is threadedly sleeved on the second screw, the pipe head and the hose input end are both fixedly sleeved in the slider, and are fixedly connected and conducted, the second impeller is vertically slidably sleeved on the main shaft, the cross plate is horizontally fixedly installed on the inner wall of the cylinder, the pressure ring and the pull ring are rotatably sleeved on the upper and lower sides of the second impeller, the second compression spring is vertically sleeved on the main shaft, and the upper and lower ends are fixedly connected to the bottom of the cross plate and the upper side of the pressure ring respectively, the second rack is vertically slidably sleeved in the top wall of the tube body, and the top is fixedly connected to the pull ring, and the third gear is meshed with the second rack.

5. The wedge-shaped differential pressure flowmeter according to claim 1, characterized in that: Two pressure-sensitive display devices are fixedly installed on the outside of the tube body and are electrically connected to the two pressure sensing devices respectively, so as to feed back the pressure data of the two pressure sensing devices.

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