Follow-up type intelligent liquid level gauge

Abstract

The present invention discloses a follow-up intelligent material level meter, which belongs to the technical field of automatic measuring equipment. The follow-up intelligent material level meter includes a material surface detector, a high temperature resistant tensile cable, a self-centering cable drum, an automatic calibration mechanism, a servo driver and a controller, etc. The material surface detector is provided with a hollow buoyancy body and a heat-resistant micro switch, which generates an electrical signal when in contact with the material surface; the high temperature resistant tensile cable serves as a traction carrier and a signal transmission carrier of the material surface detector; the self-centering cable drum is wound with a single layer of cable, which is rotated at a speed controlled by a servo driver and slides axially at a constant speed ratio; based on controller data analysis and control, the material surface controller runs in real time with the material surface, and automatically calibrates the zero point regularly; the controller outputs analog signals, alarms and communications. This device is accurate and reliable in measurement, with a high degree of intelligence, and is suitable for level measurement of powdered materials, granular materials, block materials and liquids in warehouses (tanks).

Description

Technical Field

[0001] The present invention relates to a material level detection device, in particular to a follow-up type intelligent material level meter, belonging to the technical field of automatic measurement devices. Background Art

[0002] The material level is an important parameter for the automatic control of industrial production processes; continuous, reliable, and accurate measurement of the material level is of great significance for the operation of equipment, the smooth progress of production operations, and the precise management of materials.

[0003] At present, the material level detection technologies can be divided into two categories; the first category is non-contact type, such as ultrasonic material level meters, radar material level meters, and laser ranging material level meters; the second category is contact type, such as heavy hammer type material level meters, guided wave radar material level meters, pressure type material level meters, etc.

[0004] The material level detection of powder materials, granular materials, and liquid materials is more difficult, especially the material level detection in an environment with dust or high-concentration steam. There is still no general and high-precision ideal measurement device; non-contact material level meters have strict requirements for the environmental conditions inside the silo (tank). The cross-sectional size of the silo (tank), dust concentration, steam concentration, liquid foam, etc. all have a significant impact on the detection, resulting in large errors or even being unable to be used at all; among the contact type material level meters, the guided wave radar material level meter has a relatively high detection accuracy, but its applicable conditions are relatively strict. For example, it generally requires that the dielectric constant of the material ≥ 1.4 and the viscosity ≤ 500 cst. Therefore, materials with weak reflection signals or easy adhesion such as mineral powder and carbon black are not applicable; the pressure type material level meter is only applicable to liquids with a single density; there are many types of heavy hammer type material level meters and they are widely used, but there are also certain limitations.

[0005] The heavy hammer type material level meter senses that the heavy hammer touches the material by detecting the change in the tension of the heavy hammer traction rope or the torque of the traction rope drum. At this moment, the descending length of the traction rope represents the material level; it has the following deficiencies: (1) The change in the tension of the traction rope or the torque of the traction rope drum is transmitted through the traction rope, which has the characteristics of slowness, delay, and inertia, and the measurement accuracy is poor; (2) As the traction rope descends, the self-weight of its hanging section continuously increases, and the influence on the tension of the traction rope or the torque of the traction rope drum continuously increases, and the measurement linearity is poor; (3) The heavy hammer rises and falls periodically and cannot follow the material surface, and the measurement continuity is poor; (4) The heavy hammer is prone to falling below the material surface, resulting in broken ropes or failure, and the reliability of the device is poor; (5) Generally, it cannot detect liquids; (6) The degree of intelligence is low. Summary of the Invention

[0006] The present invention aims to solve the above problems, thereby providing a follow-up type intelligent material level meter that is continuous, reliable, accurate, and intelligent for materials, especially suitable for powder materials, granular materials, high-dust bulk materials, and high-steam-concentration materials that are currently difficult to detect the material level.

[0007] To solve the above problems, the present invention adopts the following technical solutions:

[0008] A follow-up type intelligent level gauge, comprising a material surface detector, a high-temperature resistant and tensile cable, a self-aligning cable reel, a reel drive shaft, a heat-resistant microswitch, a conductive slip ring, a level gauge housing, a level gauge support, a servo driver, and a controller; the self-aligning cable reel, the servo driver, and the controller are all arranged inside the level gauge housing. The bottom of the material surface detector is connected with a telescopic slide rod by a hollow buoyancy body. The telescopic slide rod can slide up and down through a linear bearing. The upper part of the telescopic slide rod is connected with a reed push rod, and the reed push rod can trigger the heat-resistant microswitch to generate a switch contact signal; the material surface detector is suspended by a high-temperature resistant and tensile cable. The upper section of the high-temperature resistant and tensile cable is wound on the self-aligning cable reel. The self-aligning cable reel is driven by the servo driver and rotates through the internal central lead screw, and at the same time moves axially. The lead screw pitch is equal to the diameter of the high-temperature resistant and tensile cable to ensure that the high-temperature resistant and tensile cable is always aligned with the cable outlet hole; the signal of the heat-resistant microswitch is transmitted to the controller through the high-temperature resistant and tensile cable and the conductive slip ring. The controller calculates the material level according to the signal of the heat-resistant microswitch and the signal of the encoder in the servo driver, analyzes the change trend of the material level, controls the movement of the servo driver, and realizes the real-time follow-up of the material surface detector and the material surface; the controller outputs the material level data in the form of standard electrical signals and communication to the outside.

[0009] The present invention adopting the above technical solutions has the following prominent features compared with the prior art:

[0010] ① The present invention detects the material surface by generating an electric signal through the buoyancy of the hollow buoyancy body to trigger the microswitch. The trigger force required to generate this signal is only 0.4N, the trigger stroke is only 2mm, and the displacement of the material surface detector when triggering the signal is only 5mm (powder material) - 20mm (liquid material); compared with the prior art that detects tension or torque, the generation of the material level detection signal in the present invention is basically independent of factors such as the weight of the controller, the change of the cable weight with lifting, and the change of the cable tension with lifting; therefore, the present invention has high accuracy in material level detection, and the full-range measurement accuracy reaches the millimeter level.

[0011] ② When the material surface detector contacts the material surface in the present invention, only a very small buoyancy (0.4N) is required to generate an electric signal, which is only 1.5% of the weight of the material surface detector (about 30N). Moreover, the transmission and soft operation time of the electric signal are extremely short, the servo driver responds quickly, and the time for the material surface detector to stop descending from triggering the material surface is very short; therefore, the measurement of the present invention has high reliability, and the situation that the material surface detector and its hollow buoyancy body sink into the material surface will not occur.

[0012] ③In the present invention, the material surface detector realizes following the movement of the material surface. When it detects contact with the material surface, the controller controls the driver to immediately reverse and start, causing the material surface detector to separate from the material surface. The controller analyzes and predicts the material level, and sets the starting frequency, direction, and amplitude of the material surface detector in real time and dynamically according to the prediction results. Therefore, continuous measurement can be achieved in the present invention.

[0013] ④The present invention has an automatic calibration function. Every certain period of time (the calibration period can be set arbitrarily), the material surface detector automatically rises into the level gauge support, and the zero point of the material level is calibrated through the automatic calibration mechanism. This can effectively eliminate the influence of temperature fluctuations, cable deformation, changes in material properties, etc. on the measurement, and further improve the measurement accuracy and stability.

[0014] ⑤In the present invention, the self-aligning cable reel rotates at a constant speed, and the high-temperature and tensile-resistant cable is wound around the cable reel in a single layer, with each turn having an equal circumference. When the cable reel rotates, it also moves axially at the same time, and the rotation speed and axial movement speed conform to a fixed ratio. This design can ensure that the lifting speed of the material surface detector is constant (and the speed value can be set), and the cable is always aligned with the cable outlet hole when wound around the cable reel without winding overlap and cable damage, further improving the measurement accuracy and reliability.

[0015] ⑥The controller of the present invention has functions such as automatic detection, recording, analysis, prediction, follow-up control, and zero point calibration. Through the communication network, all information can be output, and the preset parameters can be set and adjusted. Therefore, the present invention has a high degree of intelligence.

[0016] ⑦The present invention belongs to a contact type level gauge, and determines the material level height by detecting the length of the traction rope when the material surface detector touches the material. Environmental factors such as dust concentration, steam concentration, and liquid foam have basically no influence on the measurement, and it can be used for various solid and liquid materials. Therefore, the present invention has strong applicability.

[0017] As a preference, a further technical solution of the present invention is:

[0018] The material surface detector consists of a hollow buoyancy body, a telescopic slide rod, a silicone sealing drum, a linear bearing, an adjustable linear bearing seat, a reed push rod, a heat-resistant micro switch, a material surface detector housing, an upper sealing cover, a lower sealing cover, an outlet nozzle, and a cable anti-disengagement clamping plate; the high-temperature and high-tensile cable passes through the outlet nozzle and penetrates into the upper sealing cover and is fastened by the cable anti-disengagement clamping plate, and its wire is connected to the heat-resistant micro switch; the linear bearing is installed on the adjustable linear bearing seat in the middle of the material surface detector housing, and the adjustable linear bearing seat can be adjusted up and down; the upper part of the telescopic slide rod is installed with a reed push rod, which contacts the trigger button of the heat-resistant micro switch. The telescopic slide rod passes through the linear bearing, then passes through the silicone sealing drum and is connected to the hollow buoyancy body through a threaded structure; the silicone sealing drum is installed between the material surface detector housing and the lower sealing cover and is fastened by the lower sealing cover; the telescopic slide rod and the silicone sealing drum are in tight interference fit. The hollow buoyancy body is a hollow sealed body with a lower spherical and upper conical shape, and the upper part is connected to the telescopic slide rod through a threaded structure; when the hollow buoyancy body touches the material surface, an upward buoyancy is generated. When the buoyancy exceeds the sum of the gravity of the hollow buoyancy body and the telescopic slide rod, the deformation force of the silicone sealing drum and the reed push rod, and the resistance of the linear bearing, the telescopic slide rod slides upward and triggers the heat-resistant micro switch, generating a switch contact signal and transmitting it to the controller through the high-temperature and high-tensile cable.

[0019] The center of the barrel of the self-aligning cable reel is a spline sleeve that mates with the reel drive shaft. One end of the outside of the spline sleeve is a nut that mates with a lead screw fixed to the level gauge housing. The pitch of the lead screw is equal to the diameter of the high-temperature and high-tensile cable; the high-temperature and high-tensile cable is wound around the surface of the barrel in a single-layer arrangement; a conductive slip ring is installed inside the barrel, its outer ring is fixed to the outer surface of the spline sleeve, and the inner ring rotates freely; when the self-aligning cable reel rotates, it moves axially at the same time, and the rotation speed and the axial movement speed conform to a fixed ratio, so that when the high-temperature and high-tensile cable is wound on the self-aligning cable reel, it is always aligned with the cable outlet hole without winding overlap and cable damage. The high-temperature and high-tensile cable is connected to the controller through the conductive slip ring, and the signal of the level controller is transmitted to the controller.

[0020] The reel drive shaft consists of a shrink disc coupling and a hollow spline shaft; the shrink disc coupling is connected to the output shaft of the servo drive and transmits the power of the servo drive to the hollow spline shaft; the hollow spline shaft mates with the spline sleeve of the self-aligning cable reel, enabling the self-aligning cable reel to slide axially.

[0021] An automatic calibration mechanism is installed inside the support pipe at the lower part of the level gauge housing. The automatic calibration mechanism consists of a calibration base, a position-holding spring, a sliding sleeve, an adjustment cover, a contact rod, and a microswitch. The calibration base is fixed inside the support pipe. The sliding sleeve is placed inside the calibration base and can slide up and down within the calibration base. The position-holding spring is installed between the calibration base and the sliding sleeve. The contact rod is installed on the sliding sleeve. A through hole is provided on the calibration base corresponding to the contact rod, and a microswitch that cooperates with the contact rod is installed at the position corresponding to the through hole. According to the program set by the controller, every certain period of time, the material surface detector rises into the support pipe, and its top contacts the sliding sleeve, thereby compressing the position-holding spring, causing the contact rod to trigger the microswitch and output a switch signal to the controller. The controller automatically takes this position as the new material level zero point to eliminate the influence of temperature fluctuations, cable deformation, changes in material properties, etc. on the measurement accuracy.

[0022] A cable sweeper is installed inside the support pipe. The cable sweeper consists of a circular skeleton and multiple groups of brushes extending towards the center. Its circular skeleton is installed inside the sliding sleeve through a threaded structure. When the high-temperature and high-tensile cable passes through the cable sweeper, the dust attached to the surface of the high-temperature and high-tensile cable is swept by the brushes to ensure the cleanliness of the surface of the high-temperature and high-tensile cable entering the level gauge housing.

[0023] The level gauge housing is composed of a housing cylinder, a left end cover, a right end cover, a conductive slip ring lever, and a support pipe. It is the external housing of the follow-up intelligent level gauge and is installed on the level gauge support through a connecting sleeve. A partition is provided on the right side inside the housing cylinder for installing the conductive slip ring lever, servo driver, and controller. The lower part of the housing cylinder is connected to the support pipe, and a wire outlet hole is provided at the central position. Flange holes are provided at both ends of the housing cylinder for installing the left end cover and the right end cover. A lead screw is provided at the center inside the left end cover of the housing cylinder, which can cooperate with the external thread of the spline sleeve of the self-aligning cable reel. The lead screw pitch is equal to the diameter of the high-temperature and high-tensile cable. Two wire outlet nozzles are provided on the right end cover of the housing cylinder for leading in or out the power cable and signal cable into the housing interior.

[0024] The connecting sleeve includes an inner sleeve flange and an outer sleeve flange. The inner sleeve flange is provided at the upper end of the level gauge support, and the outer sleeve flange is provided at the lower end of the support pipe. The inner sleeve flange and the outer sleeve flange are connected through a threaded structure. A connecting flange is provided at the lower end of the level gauge support, and the connecting flange is used for connecting the level gauge to the measured tank.

[0025] The servo driver consists of a servo motor, a servo amplifier, and a power module, and is installed on the partition inside the housing cylinder. The servo amplifier receives the forward start, reverse start, and operating speed command signals from the controller, and drives the servo motor to operate sensitively and precisely, achieving accurate operation and positioning of the self-aligning cable reel. The servo motor is equipped with an encoder, which provides the rotation speed and rotation direction signals to the servo amplifier. The power module converts the externally introduced 220VAC power into 24VDC power to provide power for the servo motor. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0027] Figure 2 It is a schematic diagram of the structure of the material surface detector in an embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the main structure of the level gauge body in an embodiment of the present invention, showing the main components of the automatic calibration mechanism, the self-aligning cable reel, the servo driver, and the level gauge housing.

[0029] Figure 4 is Figure 3 a partially enlarged schematic diagram of A in

[0030] Figure 5 It is a block diagram of the control principle of the electrical system in an embodiment of the present invention.

[0031] Figure 6 It is a schematic diagram of the installation of the device in an embodiment of the present invention.

[0032] In the figure: 1 - material surface detector; 2 - high-temperature and tensile-resistant cable; 3 - self-aligning cable reel; 4 - reel transmission shaft I; 5 - servo driver; 6 - controller; 7 - automatic calibration mechanism; 8 - cable sweeper; 9 - level gauge housing; 10 - level gauge support; 11 - hollow buoyancy body; 12 - telescopic slide rod; 13 - silicone seal drum; 14 - lower seal cover; 15 - linear bearing; 16 - adjustable linear bearing seat; 17 - reed push rod; 18 - heat-resistant microswitch; 19 - level detector housing; 20 - cable anti-disengagement clamping plate; 21 - upper seal cover; 22 - cable outlet nozzle; 23 - adjustment cover; 24 - sliding sleeve; 25 - calibration base; 26 - position holding spring; 27 - contact rod; 28 - microswitch; 29 - reel body; 30 - spline sleeve; 31 - reel transmission shaft II; 32 - conductive slip ring; 33 - servo motor; 34 - servo amplifier; 35 - power module; 36 - housing cylinder; 37 - support pipe; 38 - left end cover; 39 - right end cover; 40 - conductive slip ring lever; 41 - cable outlet nozzle; CPU - controller CPU unit; FI - pulse signal input unit; DI - digital input unit; AO - analog output unit; DO - digital output unit; ET - communication unit; A - follow-up intelligent level gauge; B - material surface detector of the level gauge; C - measured material; D - silo (tank).

[0033] The present invention will be further described below in conjunction with embodiments, and the purpose is only to better understand the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0034] See Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6, A follow-up type intelligent level gauge, comprising a material surface detector 1, a high-temperature resistant and tensile cable 2, a self-aligning cable reel 3, a first reel transmission shaft 4, a heat-resistant microswitch 18, a conductive slip ring 32, a level gauge housing 9, a level gauge support 10, a servo driver 5, and a controller 6; The self-aligning cable reel 3, the servo driver 5, and the controller 6 are all placed inside the level gauge housing 9. The bottom of the material surface detector 1 is connected to a telescopic slide rod 12 by a hollow buoyancy body 11. The telescopic slide rod 12 can slide up and down through a linear bearing 15. The upper part of the telescopic slide rod 12 is connected to a reed push rod 17, and the reed push rod 17 can trigger the heat-resistant microswitch 18 to generate a switch contact signal; The material surface detector 1 is suspended by the high-temperature resistant and tensile cable 2. The upper section of the high-temperature resistant and tensile cable 2 is wound on the self-aligning cable reel 3. The self-aligning cable reel 3 is driven by the servo driver 5 and rotates through the internal central lead screw, and at the same time moves axially. The lead screw pitch is equal to the diameter of the high-temperature resistant and tensile cable 2 to ensure that the high-temperature resistant and tensile cable 2 is always aligned with the cable outlet hole; The signal of the heat-resistant microswitch 18 is transmitted to the controller 6 through the conductive slip ring 32 via the high-temperature resistant and tensile cable 2. The controller 6 calculates the material level based on the signal of the heat-resistant microswitch 18 and the signal of the encoder in the servo driver 5, analyzes the change trend of the material level, controls the movement of the servo driver 5, and realizes the real-time follow-up of the material surface detector 1 and the material surface; The controller 6 outputs the material level data in the form of standard electrical signals and communication to the outside.

[0035] The material surface detector 1 is composed of a hollow buoyancy body 11, a telescopic slide rod 12, a silicone sealing drum 13, a linear bearing 15, an adjustable linear bearing seat 16, a reed push rod 17, a heat-resistant microswitch 18, a material surface detector housing 19, an upper sealing cover 21, a lower sealing cover 14, an outlet nozzle 22, and a cable anti-disengagement card plate 20; The high-temperature resistant and tensile cable 2 passes through the outlet nozzle 22 and penetrates into the upper sealing cover 21 and is fastened by the cable anti-disengagement card plate 20. Its wire is connected to the heat-resistant microswitch 18; The linear bearing 15 is installed on the adjustable linear bearing seat 16 in the middle of the material surface detector housing 19, and the adjustable linear bearing seat 16 can be adjusted up and down; The upper part of the telescopic slide rod 12 is installed with a reed push rod 17, which contacts the trigger button of the heat-resistant microswitch 18. The telescopic slide rod 12 passes through the linear bearing 15 and is then connected to the hollow buoyancy body 11 through the silicone sealing drum 13 by a threaded structure; The silicone sealing drum 13 is installed between the material surface detector housing 19 and the lower sealing cover 14 and is fastened by the lower sealing cover 14; The telescopic slide rod 12 is in a tight interference fit with the silicone sealing drum 13. The hollow buoyancy body 11 is a lower spherical and upper conical hollow sealed body, and the upper part is connected to the telescopic slide rod 12 by a threaded structure; When the hollow buoyancy body 11 touches the material surface, an upward buoyancy is generated. When the buoyancy exceeds the sum of the gravity of the hollow buoyancy body 11 and the telescopic slide rod 12, the deformation force of the silicone sealing drum 13 and the reed push rod 17, and the resistance of the linear bearing 15, the telescopic slide rod 12 slides upward and triggers the heat-resistant microswitch 18 to generate a switch contact signal and transmit it to the controller 6 through the high-temperature resistant and tensile cable 2.

[0036] The high-temperature and tensile-resistant cable 2 is a cable that connects the material surface detector 1 and the controller 6, and at the same time is a cable for pulling the material surface detector 1 up and down. Its heat-resistant temperature is ≥200°C, and its tensile capacity is ≥3 times the weight of the material surface detector 1. Its lower end is fixed to the material surface detector 1 through a cable anti-disconnection card 20, and the wire is connected to the heat-resistant micro-switch 18. The upper end is wound around the self-aligning cable reel 3, and the wire is connected to the controller 6 through the slip ring 32.

[0037] The self-aligning cable reel 3 is a component that winds the high-temperature and tensile-resistant cable 2 to lift and lower the material surface detector 1. It consists of a reel body 29 and a slip ring 32. In the center of the reel body 29 is a spline sleeve 30 that cooperates with the reel transmission shaft 31. One end of the outer part of the spline sleeve 30 is a nut that cooperates with a lead screw fixed on the level gauge housing 9. The pitch of the lead screw is equal to the diameter of the high-temperature and tensile-resistant cable 2. The high-temperature and tensile-resistant cable 2 is wound around the surface of the cylinder body in a single-layer arrangement. The slip ring 32 is fixed on the outer surface of the spline sleeve 30 and is used to connect the wire output from the material surface detector 1 and the wire input to the controller 6. The inner ring rotates freely. When the self-aligning cable reel 3 rotates, it moves axially at the same time, and the rotation speed and the axial movement speed conform to a fixed ratio, so that the high-temperature and tensile-resistant cable 2 is always aligned with the cable outlet hole when wound around the self-aligning cable reel 3 without winding overlap and cable damage. The high-temperature and tensile-resistant cable 2 is connected to the controller 6 through the slip ring 32 to transmit the signal of the material surface detector 1 to the controller 6.

[0038] The reel transmission shaft two 31 is a component that transmits the torque output by the servo driver 5 to the self-aligning cable reel 3. It consists of a expansion sleeve coupling and a hollow spline shaft. The expansion sleeve coupling is connected to the output shaft of the servo driver 5 to transmit the power of the servo driver 5 to the hollow spline shaft. The hollow spline shaft cooperates with the spline sleeve 30 of the self-aligning cable reel 3, so that the self-aligning cable reel 3 can slide axially.

[0039] An automatic calibration mechanism 7 is installed inside the support pipe 37 at the lower part of the level gauge housing 9. The automatic calibration mechanism 7 is a component that completes the automatic calibration of the follow-up intelligent level gauge, and is composed of a calibration base 25, a position-holding spring 26, a sliding sleeve 24, an adjustment cover 23, a contact rod 27, and a microswitch 28. The calibration base 25 is fixed inside the support pipe 37. The sliding sleeve 24 is placed inside the calibration base 25 and can slide up and down inside the calibration base 25. The position-holding spring 26 is installed between the calibration base 25 and the sliding sleeve 24. The contact rod 27 is installed on the sliding sleeve 24. A through hole is provided on the calibration base 25 corresponding to the contact rod 27, and a microswitch 28 that cooperates with the contact rod 27 is installed at the position corresponding to the through hole. According to the program set by the controller 6, every certain period of time, the material surface detector 1 rises into the support pipe 37, and its top contacts the sliding sleeve 24, thereby compressing the position-holding spring 26, causing the contact rod 27 to trigger the microswitch 28 and output a switch signal to the controller 6. The controller 6 automatically takes this position as the new level zero point to eliminate the influence of temperature fluctuations, cable deformation, material property changes, etc. on the measurement accuracy.

[0040] A cable sweeper 8 is installed inside the support pipe 37. The cable sweeper 8 is a component that completes the automatic cleaning of the dust on the surface of the high-temperature and tensile-resistant cable 2, and is composed of a circular skeleton and multiple groups of brushes extending towards the center. Its circular skeleton is installed inside the sliding sleeve 24 through a threaded structure. When the high-temperature and tensile-resistant cable 2 passes through the cable sweeper 8, the dust attached to the surface of the high-temperature and tensile-resistant cable 2 is cleaned by the brushes to ensure the cleanliness of the surface of the high-temperature and tensile-resistant cable entering the level gauge housing 9.

[0041] The level gauge housing 9 is composed of a housing cylinder 36, a left end cover 38, a right end cover 39, a conductive slip ring lever 40, and a support pipe 37. It is the external housing of the follow-up intelligent level gauge and is installed on the level gauge support 10 through a connecting sleeve. A partition is provided on the right side inside the housing cylinder 36 for installing the conductive slip ring lever 40, the servo driver 5, and the controller 6. The lower part of the housing cylinder 36 is connected to the support pipe 37, and a wire outlet hole is provided at the center position. Flange holes are provided at both ends of the housing cylinder 36 for installing the left end cover 38 and the right end cover 39. A lead screw is provided at the center inside the left end cover 38 of the housing cylinder 36, which can cooperate with the external thread of the spline sleeve 30 of the self-aligning cable reel 3. The lead screw pitch is equal to the diameter of the high-temperature and tensile-resistant cable 2. Two wire outlet nozzles 41 are provided on the right end cover 39 of the housing cylinder 36 for leading the power cable and the signal cable in or out of the housing.

[0042] The connecting sleeve includes an inner sleeve flange and an outer sleeve flange. The inner sleeve flange is arranged at the upper end of the level gauge support 10, and the outer sleeve flange is arranged at the lower end of the support pipe 37. The inner sleeve flange and the outer sleeve flange are connected through a threaded structure. A connecting flange is provided at the lower end of the level gauge support 10, and the connecting flange is used for connecting the level gauge to the measured tank.

[0043] The servo drive 5 is a component that drives the self-aligning cable reel 3 to operate and position precisely according to the instructions of the controller. It is composed of a servo motor 33, a servo amplifier 34, and a power supply module 35, and is installed on the partition inside the housing cylinder 36. The servo amplifier 34 receives the forward start, reverse start, and operating speed command signals from the controller 6, and drives the servo motor 33 to operate sensitively and precisely, so as to achieve the precise operation and positioning of the self-aligning cable reel 3. The servo motor 33 is equipped with an encoder, which provides the rotational speed and rotation direction signals to the servo amplifier 34. The power supply module 35 converts the externally introduced 220VAC power into 24VDC power to provide power for the servo motor 33.

[0044] The controller 6 is the core component that controls the operation of the servo drive 5, analyzes and calculates the material level, records the historical data of the material level, analyzes and predicts the trend of the material level, makes real-time adjustments to the servo drive 5 according to the prediction, and outputs the measurement result information. The controller 6 includes a CPU and input / output circuit components, and software is built into the CPU. The controller is installed on the partition inside the housing cylinder 36. The controller 6 has the following functions: receiving the signals from the material surface detector 1 and the encoder of the servo motor 33, and obtaining the material level measurement value through signal processing and data operation; storing the measured material level values to form a historical record; performing non-linear fitting on the historical data to form a continuous function of the material level with respect to time; predicting the material level by taking the second derivative of the material level function; according to the predicted value of the change direction and amplitude of the material level at the next moment, sending command signals such as the detection frequency, the lifting direction and speed of the material surface detector 1 to the servo amplifier 34, controlling the servo motor 33 to rotate a certain angle at a certain frequency, direction and speed, driving the self-aligning cable reel 3, and further controlling the material surface detector 1 to move up and down following the material surface, so as to meet the measurement accuracy without causing ineffective frequent starts; outputting the measurement results to external devices (such as: PC, DCS, PLC, DDC, etc.) in two optional ways: through a communication network and electrical signals; sending a zero calibration signal to the servo amplifier 34 according to the preset time interval or external instruction, receiving the signal from the automatic calibration mechanism 7, and adjusting the relevant software parameters to achieve zero calibration; the range and other parameters can be adjusted or reset by a computer through a communication network.

[0045] The built-in software of the controller 6 records the measured material level and its corresponding time; calculates the data before the current time with a nonlinear fitting model to form a continuous function y=f(t) of the material level y to time t; performs the first-order derivative y′=dy / dx and the second-order derivative y″=dy′ / dt of the function; predicts the material level y(t1) at the next moment t1 after the current moment t based on the values ​​of y′(t) and y″(t); obtains the change in the material level Δy(t)=y(t1)-y(t) at the next moment; sets the frequency, direction and speed of the lifting and lowering of the material surface detector 1 at the current moment based on the value of Δy(t); transmits the above values ​​to the servo motor 33, drives the self-centering cable reel 3, and then controls the probe to follow the material surface, while meeting the measurement accuracy without frequent ineffective starting and stopping.

[0046] The controller 6 outputs the material level value to the external equipment (such as DCS, PLC, digital instrument, etc.) with 4-20mA current, 0-20mA current and 0-10V voltage signal; at the same time, it outputs four material level threshold alarms, as well as the normal / fault status, running / stop status and other information of the device to the external equipment with normally open dry contact and normally closed dry contact signals.

[0047] The controller 6 establishes a communication network with external devices (such as DCS, PLC, PC, etc.) through a communication interface based on RS485 protocol. Through this network, the device can output real-time material level data and historical material level data; and through this network, the PC can be used to perform zero point calibration, range setting, alarm threshold setting and other calculation parameter setting on the device.

[0048] The material surface detector 1 of the present invention is connected to the self-aligning cable reel 3 through the high-temperature resistant and tensile cable 2. The controller 6 controls and drives the rotation of the self-aligning cable reel 3 through the servo driver 5 and the first drum transmission shaft 4, so that the material surface detector 1 moves up and down in the bin (tank). When the material surface detector 1 descends to the material surface, a material level signal is generated and transmitted to the controller 6. At the same time, the material surface detector 1 is lifted a small distance to get away from the material surface. The controller 6 calculates, records, analyzes and predicts the signals of the material surface detector 1, the encoder of the servo motor 33, etc., and controls the material surface detector 1 to lift and lower at a certain frequency and amplitude, so that the material surface detector 1 forms a follow-up movement along with the material surface. The automatic calibration mechanism 7 rises into the level gauge support 10 every certain period of time according to the set program. The top of the material surface detector 1 contacts the sliding sleeve 24, and then compresses the position maintaining spring 26, so that the contact rod 27 triggers the micro switch 28 to perform automatic zero calibration to eliminate the influence of temperature change, wire elongation and material change on the measurement accuracy. The protection level of the level gauge housing 9 reaches IP68, and all moving parts and electrical parts are installed in the housing. The level gauge support 10 is used for connecting the level gauge to the bin (tank) body. A cable sweeper 8 is arranged in the support pipe 37. When the high-temperature resistant and tensile cable 2 passes through, the dust attached to the cable surface is swept to ensure the cleanliness of the cable surface entering the level gauge housing 9. The high-temperature resistant and tensile cable 2 passes through the outlet nozzle 22 and penetrates into the upper sealing cover 21 and is fastened by the cable anti-detachment clamping plate 20. Its wire is connected to the heat-resistant micro switch 18. The other end of the high-temperature resistant and tensile cable 2 passes through the level gauge support 10, the cable sweeper 8 and the automatic calibration mechanism 7 and enters the level gauge housing 9, winds around the drum body 29 and is fixed in the drum body 29 by the clamping plate through the wire passing hole of the drum body 29. Its wire is connected to the inner ring outlet of the conductive slip ring 32. The outer ring outlet of the conductive slip ring 32 is connected to the controller 6 through a spring wire. The material surface detector 1 rises and falls under the drive of the servo driver 5 through the first drum transmission shaft 4 and the self-aligning cable reel 3. When the material surface detector 1 descends to the material surface height, the hollow buoyancy body 11 first contacts the material surface. The hollow buoyancy body 11 receives an upward buoyancy force. When the buoyancy force exceeds 0.4N, the reed push rod 17 rises to trigger the internal heat-resistant micro switch 18, and the heat-resistant micro switch 18 generates a switch contact signal and transmits it to the controller 6 through the cable. The controller 6 and its software calculate the position of the material surface detector 1 through the encoder signal of the servo motor 33, and then calculate the material level, and record, analyze and predict the data, and output the material level data to the outside in the form of electrical signals and communication signals; at the same time, the controller 6 sends a command signal to the servo driver 5, which drives the servo motor 33 through the amplifier, and then rotates the self-centering cable drum 3, so that the material surface detector 1 is lifted a small distance to leave the material surface; the controller The material level historical records are used to predict the trend, and a signal is sent out according to the analysis results, so that the material level detector 1 rises and falls at a certain frequency and amplitude, and finally the material level detector 1 moves along with the material level; wherein, the micro switch 28 is a dry contact open signal type, with high sensitivity, and its trigger force is not greater than 0.15N; the hollow buoyancy body 11 is a conical stainless steel hollow body on the top of the ball, with a mass of about 250g, to maximize the buoyancy and reduce the dust accumulation on it; the telescopic slide 12 is a cylindrical smooth metal straight rod, and the resistance to up and down movement in the linear bearing 15 is ≤0.05N, and its up and down movement is limited by mechanical limit, and the distance is ≤6mm. The telescopic slide 12 and the outer shell of the material level detector 1 are sealed with a silicone sealing drum, and the temperature resistance is 200℃. The tensile cable is used as both the traction carrier of the material level detector 1 and the transmission carrier of the micro switch signal. Its cross section is circular, the number of wire cores is 3, and the length is 1 to 50m according to the material level range. It is fixed on the material level detector housing 19 through a wire clamp. The lower end of the wire is connected to the micro switch 28, and the upper end is connected to the inner ring of the conductive slip ring 32 through the self-centering cable reel 3.

[0049] The present invention detects the material surface through the electric signal generated by the microswitch triggered by the buoyancy generated by the hollow buoyancy body 11. The triggering force required to generate this signal is only 0.4 N, the triggering stroke is only 2 mm, and the displacement of the material surface detector when triggering the signal is only 5 mm (powder material) to 20 mm (liquid material); compared with the existing technology of detecting tension or torque, the generation of the material level detection signal in the present invention is basically independent of factors such as the weight of the controller, the change of the cable weight with lifting, and the change of the cable tension with lifting; therefore, the present invention has high accuracy in material level detection, and the full-range measurement accuracy reaches the millimeter level; when the material surface detector 1 contacts the material surface in the present invention, only a very small buoyancy (0.4 N) is required to generate an electric signal, which is only 1.5% of the weight of the material surface detector (about 30 N), and the transmission and soft operation time of the electric signal are extremely short, and the servo driver 5 responds quickly. The time from when the material surface detector 1 triggers the material surface to stop descending is very short; therefore, the measurement of the present invention has high reliability, and the situation where the material surface detector 1 and its hollow buoyancy body 11 sink into the material surface will not occur; in the present invention, the material surface detector 1 realizes following the movement of the material surface. When it is detected that the material surface detector 1 contacts the material surface, the controller 6 controls the driver to immediately start in the reverse direction to separate the material surface detector 1 from the material surface. The controller 6 analyzes and predicts the material level, and sets the starting frequency, direction, and amplitude of the material surface detector 1 in real time and dynamically according to the prediction result; therefore, the present invention can realize continuous measurement; the present invention has an automatic calibration function. Every certain period of time (the calibration period can be set arbitrarily), the material surface detector 1 automatically rises into the level gauge support 10, and the material level zero point calibration is carried out through the automatic calibration mechanism 7, which can effectively eliminate the influence of temperature fluctuations, cable deformation, material property changes, etc. on the measurement, and further improve the measurement accuracy and stability; in the present invention, the self-aligning cable reel 3 rotates at a constant speed, and the high-temperature and tensile-resistant cable 2 is wound in a single layer on the self-aligning cable reel 3, and the circumference of each turn is equal; when the self-aligning cable reel 3 rotates, it also moves axially at the same time, and the rotation speed and the axial movement speed conform to a fixed ratio; this design can ensure that the lifting speed of the material surface detector 1 is constant (and the speed value can be set), and the cable is always aligned with the cable outlet hole when wound on the self-aligning cable reel 3 without winding overlap and cable damage, further improving the measurement accuracy and reliability; the controller of the present invention has functions such as automatic detection, recording, analysis, prediction, follow-up control, zero point calibration, etc. Through the communication network, all information can be output, and the preset parameters can be set and adjusted. Therefore, the present invention has a high degree of intelligence; the present invention belongs to a contact type level gauge, and determines the material level height by detecting the length of the towing rope when the material surface detector 1 touches the material. Environmental factors such as dust concentration, steam concentration, and liquid foam have basically no influence on the measurement, and it can be used for various solid materials and liquid materials; therefore, the present invention has strong applicability.

[0050] The above are only the preferred and feasible embodiments of the present invention, and thus do not limit the scope of the rights of the present invention. Any equivalent changes made by using the content of the specification and drawings of the present invention are included within the scope of the rights of the present invention.

Claims

1. A follow-up type intelligent liquid level gauge, comprising a liquid surface detector, a high-temperature resistant and tensile-resistant cable, a self-aligning cable reel, a reel transmission shaft, a heat-resistant microswitch, a conductive slip ring, a liquid level gauge housing, a liquid level gauge support, a servo driver, and a controller; characterized in that: The self-aligning cable reel, servo driver, and controller are all placed inside the level gauge housing. At the bottom of the level detector, a telescopic slide rod is connected by a hollow buoyancy body. The telescopic slide rod can slide up and down through a linear bearing. The upper part of the telescopic slide rod is connected to a reed push rod, which can trigger a heat-resistant micro switch to generate a switch contact signal. The level detector is suspended by a high-temperature and high-tensile cable. The upper section of the high-temperature and high-tensile cable is wound around the self-aligning cable reel. The self-aligning cable reel is driven by a servo driver and rotates through the internal central lead screw, and at the same time moves axially. The lead screw pitch is equal to the diameter of the high-temperature and high-tensile cable to ensure that the high-temperature and high-tensile cable is always aligned with the cable outlet hole. The signal of the heat-resistant micro switch is transmitted to the controller through the high-temperature and high-tensile cable via a conductive slip ring. The controller calculates the level based on the signal of the heat-resistant micro switch and the signal of the encoder in the servo driver, analyzes the change trend of the level, stores the measured level value to form a historical record, performs non-linear fitting on the historical data to form a continuous function of the level versus time, and conducts level prediction. According to the predicted value of the change direction and amplitude of the level at the next moment, it sends command signals of the detection frequency, the lifting direction and speed of the level detector to the servo amplifier, controls the servo motor to rotate a certain angle at a certain frequency, direction and speed, drives the self-aligning cable reel, and further controls the level detector to move up and down following the material level, controls the movement of the servo driver and realizes the real-time follow-up of the level detector and the material level. The controller outputs the level data in the form of standard electrical signals and communication to the outside.

2. The follow-up type intelligent level gauge according to claim 1, characterized in that: The level detector is composed of a hollow buoyancy body, a telescopic slide rod, a silicone sealing drum, a linear bearing, an adjustable linear bearing seat, a reed push rod, a heat-resistant micro switch, a level detector housing, an upper sealing cover, a lower sealing cover, a cable outlet nozzle, and a cable anti-disengagement clamping plate. The high-temperature and high-tensile cable passes through the cable outlet nozzle and penetrates into the upper sealing cover and is fastened by the cable anti-disengagement clamping plate. Its wire is connected to the heat-resistant micro switch. The linear bearing is installed on the adjustable linear bearing seat in the middle of the level detector housing, and the adjustable linear bearing seat can be adjusted up and down. The upper part of the telescopic slide rod is installed with a reed push rod, which contacts the trigger button of the heat-resistant micro switch. The telescopic slide rod passes through the linear bearing and is then connected to the hollow buoyancy body through a threaded structure via the silicone sealing drum. The silicone sealing drum is installed between the level detector housing and the lower sealing cover and is fastened by the lower sealing cover. The telescopic slide rod and the silicone sealing drum are in a tight interference fit. The hollow buoyancy body is a hollow sealing body with a lower spherical and upper conical shape, and is connected to the telescopic slide rod through a threaded structure at the upper part. When the hollow buoyancy body touches the material surface, an upward buoyancy is generated. When the buoyancy exceeds the sum of the gravity of the hollow buoyancy body and the telescopic slide rod, the deformation force of the silicone sealing drum and the reed push rod, and the resistance of the linear bearing, the telescopic slide rod slides upward and triggers the heat-resistant micro switch, generating a switch contact signal and transmitting it to the controller through the high-temperature and high-tensile cable.

3. The follow-up type intelligent liquid level gauge according to claim 1, characterized in that: In the center of the cylinder body of the self-aligning cable reel, there is a spline sleeve that mates with the reel drive shaft. At one end outside the spline sleeve, there is a nut that mates with the lead screw fixed on the level gauge housing. The lead screw pitch is equal to the diameter of the high-temperature and high-tensile cable. The surface of the cylinder body is wound with high-temperature resistant and tensile cables in a single-layer arrangement; a conductive slip ring is installed inside the cylinder body, the outer ring of which is fixed on the outer surface of the spline sleeve, and the inner ring rotates freely; when the self-aligning cable reel rotates, it moves axially at the same time, and the rotation speed and the axial movement speed conform to a fixed ratio, so that when the high-temperature resistant and tensile cable is wound on the self-aligning cable reel, it is always aligned with the cable outlet hole without winding overlap and cable damage. The high-temperature resistant and tensile cable is connected to the controller through the conductive slip ring to transmit the signal of the level controller to the controller.

4. The follow-up type intelligent level gauge according to claim 1, characterized in that: The reel transmission shaft is composed of a expansion sleeve coupling and a hollow spline shaft; the expansion sleeve coupling is connected to the output shaft of the servo drive to transmit the power of the servo drive to the hollow spline shaft; the hollow spline shaft cooperates with the spline sleeve of the self-aligning cable reel, so that the self-aligning cable reel can slide axially.

5. The follow-up type intelligent level gauge according to claim 1, wherein: An automatic calibration mechanism is installed inside the support tube at the lower part of the level gauge housing. The automatic calibration mechanism is composed of a calibration base, a position-holding spring, a sliding sleeve, an adjustment cover, a contact rod and a micro switch; the calibration base is fixed inside the support tube, the sliding sleeve is placed inside the calibration base and can slide up and down inside the calibration base, the position-holding spring is installed between the calibration base and the sliding sleeve, the contact rod is installed on the sliding sleeve, through holes are provided on the calibration base corresponding to the contact rod, and a micro switch cooperating with the contact rod is installed at the position corresponding to the through holes. According to the program set by the controller, every certain period of time, the level detector rises into the support tube, and its top contacts the sliding sleeve, thereby compressing the position-holding spring, causing the contact rod to trigger the micro switch and output a switch signal to the controller; the controller automatically takes this position as the new level zero point to eliminate the influence of temperature fluctuation, cable deformation and material property change on the measurement accuracy.

6. The follow-up type intelligent level gauge according to claim 5, characterized in that: A cable cleaner is installed inside the support tube. The cable cleaner is composed of a circular skeleton and multiple groups of brushes extending towards the center; its circular skeleton is installed inside the sliding sleeve through a threaded structure; when the high-temperature resistant and tensile cable passes through the cable cleaner, the dust attached to the surface of the high-temperature resistant and tensile cable is cleaned by the brushes to ensure the cleanliness of the surface of the high-temperature resistant and tensile cable entering the level gauge housing.

7. The follow-up type intelligent level gauge according to claim 1, wherein: The level gauge housing is composed of a housing cylinder, a left end cover, a right end cover, a conductive slip ring lever and a support tube, which is the outer housing of the follow-up type intelligent level gauge and is installed on the level gauge support through a connecting sleeve; a partition is provided on the right side inside the housing cylinder for installing the conductive slip ring lever, the servo drive and the controller; the lower part of the housing cylinder is connected to the support tube, and a wire outlet hole is provided at the central position; flange holes are provided at both ends of the housing cylinder for installing the left end cover and the right end cover; a lead screw is provided at the center inside the left end cover of the housing cylinder, which can cooperate with the external thread of the spline sleeve of the self-aligning cable reel, and the lead screw pitch is equal to the diameter of the high-temperature resistant and tensile cable; two wire outlet nozzles are provided on the right end cover of the housing cylinder for leading out or leading into the power cable and the signal cable inside the housing.

8. The follow-up type intelligent level gauge according to claim 7, characterized in that: The connecting sleeve includes an inner sleeve flange and an outer sleeve flange. The inner sleeve flange is arranged at the upper end of the level gauge support, and the outer sleeve flange is arranged at the lower end of the support pipe. The inner sleeve flange and the outer sleeve flange are connected through a threaded structure. A connecting flange is arranged at the lower end of the level gauge support, and the connecting flange is used for connecting the level gauge with the measured tank body.

9. The follow-up type intelligent liquid level gauge according to claim 7, characterized in that: The servo driver is composed of a servo motor, a servo amplifier, and a power module, and is installed on the partition inside the housing cylinder; the servo amplifier receives the forward start, reverse start, and running speed command signals from the controller, drives the servo motor to run sensitively and precisely, and realizes the precise running and positioning of the self-aligning cable reel; the servo motor is equipped with an encoder, which provides the rotation speed and rotation direction signals to the servo amplifier; the power module converts the externally introduced 220VAC power into 24VDC power to provide power for the servo motor.

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