Burette liquid level scale calibration machine and quantitative scale calibration method thereof

Abstract

The invention discloses a burette liquid level scale calibration machine and a quantitative scale calibration method thereof.The burette liquid level scale calibration machine comprises a rack fixed to the rear side of a workbench, a ball screw extending in the vertical direction is arranged in the middle of the front end face of the rack, and the upper end of the ball screw is driven by a servo motor; vertical guide rails are symmetrically arranged on the two sides of the ball screw, and the two ends of the rear side of the floating platform are supported on the vertical guide rails through guide sliding blocks and connected with the ball screw through screw nuts; the glass tube support is fixed to the workbench and used for supporting a glass tube. The code spraying device is mounted on the floating platform; and the injector is used for injecting purified water into the glass tube. The method comprises the steps that a first water inlet valve is opened, and purified water enters an injector; the second water inlet valve is opened, and water in the injector is injected into the glass tube to reach the initial water level; filling the injector; the servo motor drives the floating platform to ascend and descend, and the photoelectric switch stops when detecting the liquid level; spraying scale marks on the glass tube; and repeating the steps. The device is good in product quality and low in labor intensity.

Description

Technical Field

[0001] The present invention relates to a burette production device, in particular to a burette liquid level scale calibration machine. The present invention also relates to a quantitative scale calibration method for burettes, belonging to the technical field of measuring instrument calibration. Background Art

[0002] As a common experimental instrument, burettes are widely used in fields such as chemical analysis. Their accuracy directly affects the accuracy of experimental results. The scale on the burette is one of its key parts, used to accurately measure the volume of liquid. The most common burettes on the market are 50ml and 100ml. For a 50ml burette, "one"-shaped calibration lines need to be drawn at 0 and 50ml respectively, and then the scale will be printed, dried, etc. according to the calibration lines. For a 100ml burette, "one"-shaped calibration lines need to be drawn at 0, 50, and 100ml respectively, and then the scale will be printed, dried, etc. according to the calibration lines.

[0003] The scale on the burette was originally engraved manually. The operator observed the liquid level in the burette with eyes and then marked the reference line with a fine brush. This operation method is easily interfered by various factors. For example, when the eyes are fatigued, the operator's judgment of the liquid level position will deviate, resulting in an inaccurate calibrated reference line. Moreover, there are differences in the eyesight and operating habits of different operators, making it difficult to maintain the consistency of the calibration results, which in turn affects the subsequent scale engraving, resulting in unstable burette quality and low yield. In addition, manual engraving requires extremely high eyesight from the operator, who needs to observe the minute changes in the liquid level at a close distance for a long time. Engaging in such work for a long time will gradually reduce the operator's eyesight, not only affecting work efficiency but also causing harm to the health of employees. During the calibration process, the operator needs to stand up and sit down continuously, frequently adjusting the observation angle and operating posture. This repetitive physical labor easily leads to physical fatigue, thereby affecting the accuracy of the operation and the stability of product quality.

[0004] Later, the scale was printed by screen printing. Although screen printing improved the efficiency and aesthetics of scale production to a certain extent, the calibration of the reference line still relied on manual operation during the calibration process. Therefore, the above problems of manual calibration of the reference line still exist. Moreover, during the screen printing process, if the reference line is inaccurate, the printed scale will also deviate, making it difficult to ensure the overall quality of the burette.

[0005] In some improvement attempts, a reflective optoelectronic switch is used to assist in calibrating the reference line. However, this optoelectronic switch is greatly affected by the fluctuations of the concave surface of water and natural light. For example, when the liquid level fluctuates, the signal detected by the optoelectronic switch becomes unstable, resulting in an inaccurate calibrated reference line. The change in the intensity of natural light also interferes with the normal operation of the optoelectronic switch, making it difficult to accurately carry out the calibration process.

[0006] The above calibration and scale production processes highly depend on the skill levels of workers. Different workers have different degrees of mastery of operation specifications and uneven technical levels, making it difficult to achieve large-scale production. This not only limits the output of burettes but also makes it difficult to uniformly control the product quality and meet the large market demand for high-precision burettes.

[0007] In summary, there are many defects and problems in the traditional method of making burette scales. The method of manually calibrating the reference line has unstable quality, low yield rate, high requirements for the eyesight and physical strength of operators, high labor intensity, and is difficult to achieve large-scale production. And using auxiliary means such as reflective optoelectronic switches is also difficult to effectively solve these problems. Therefore, there is an urgent need for a new technical solution to overcome the deficiencies of the existing technology, improve the accuracy, efficiency, and quality stability of burette scale production, and meet the market demand for high-precision burettes. Summary of the Invention

[0008] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part as well as in the abstract and title of the present application, but such simplifications or omissions shall not be used to limit the scope of the present invention.

[0009] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0010] The primary objective of the present invention is to overcome the problems existing in the prior art and provide a burette liquid level scale calibrator that can accurately calibrate the scale on the outer wall of the burette, reduce errors, improve product quality, and reduce labor intensity.

[0011] To solve the above technical problems, a burette liquid level scale calibrator of the present invention includes: A workbench 1; A frame 2, fixed to the rear side of the workbench 1. In the middle of the front end face of the frame 2, there is a ball screw 4 extending vertically. The upper end of the ball screw 4 is driven by a servo motor 3, and the servo motor 3 is fixed to the top of the frame 2; Vertical guide rails 5, symmetrically arranged on both sides of the ball screw 4 and fixed to the front end face of the frame 2; The floating platform 10 is supported on the vertical guide rail 5 at both rear ends thereof through guide sliders, and the middle part of the rear side of the floating platform 10 is connected to the lead screw nut on the ball screw 4; The glass tube bracket 8 is fixed on the workbench 1 and is used for supporting the glass tube 7; The inkjet printer 14 is installed on the floating platform 10 and is used for printing calibration lines on the outer wall of the glass tube 7; The syringe 25 is used for injecting purified water into the glass tube 7.

[0012] As an improvement of the present invention, an opposed photoelectric switch bracket 21 is further fixed on the floating platform 10, and a pair of photoelectric switches are installed on the opposed photoelectric switch bracket 21, which are used for detecting the liquid level position in the glass tube 7 and sending signals to the control system.

[0013] As a further improvement of the present invention, it further includes: The carriage base 15 is fixed on the floating platform 10, and a carriage guide rail 16 extending in the left - right direction is provided on the carriage base 15; The carriage slide 17 translates left and right along the carriage guide rail 16. A carriage 18 is fixed above the carriage slide 17, and the opposed photoelectric switch bracket 21 is installed at one end of the carriage 18; The carriage adjusting lead screw 19 is engaged with a carriage lead screw nut, and the carriage lead screw nut is connected to the carriage slide 17 and is used for adjusting the position of the opposed photoelectric switch bracket 21 so that the photoelectric switch passes through the center of the glass tube; The carriage adjusting handwheel 20 is fixed at the end of the carriage adjusting lead screw 19 and is used for manually adjusting the carriage adjusting lead screw 19.

[0014] As a further improvement of the present invention, an inkjet base 11 is fixed on the floating platform 10. An inkjet guide rail 12 extending in the left - right direction is provided at the top of the inkjet base 11. The bottom of the inkjet printer 14 is supported on the inkjet guide rail 12. An inkjet cylinder 13 is installed at the outer end of the inkjet base 11. The piston rod of the inkjet cylinder 13 drives the inkjet printer 14 to translate left and right along the inkjet guide rail 12. The inkjet printer 14 and the opposed photoelectric switch bracket 21 are respectively located on the left and right sides of the glass tube.

[0015] As a further improvement of the present invention, a glass tube base 6 is provided on the front side of the glass tube bracket 8. The glass tube base 6 is fixed on the workbench 1. The lower end of the glass tube 7 is inserted into the glass tube base 6 and is sealed; A glass tube clamp 9 is installed on the upper part of the glass tube bracket 8, and the glass tube clamp 9 clamps the upper part of the glass tube 7 to keep it in a vertical state; A vertical long groove is provided along the axis of the glass tube bracket 8 to adjust the height of the glass tube clamp 9.

[0016] As a further improvement of the present invention, a syringe support 24 extending upward is also fixed on the workbench 1. The syringe 25 is fixed to the upper part of the syringe support 24 with the syringe barrel facing downward, and a weight 26 that pushes its piston rod downward is pressed on the top of the piston rod of the syringe 25. A water tank 23 higher than the syringe 25 is provided outside the workbench 1. The outlet of the water tank 23 is connected to the inlet of the first water inlet valve V1 through a water supply pipe. The outlet of the first water inlet valve V1 is connected to the inlet of the second water inlet valve V2 and the syringe 25 respectively through a tee. The second water inlet valve V2 is connected to the side wall inlet of the glass tube base 6 through an injection water pipe, and the glass tube base 6 is connected with a drain valve V3.

[0017] As a further improvement of the present invention, the control system includes a Mitsubishi servo controller MR-J2S-200A and a Mitsubishi PLC controller FX1S-30MT. The PLC controller is communicatively connected to the servo controller. The PLC controller sends pulse signals and direction control signals to the servo controller through its output ports Y0 and Y2. The servo controller controls the forward and reverse rotation and speed of the servo motor 3 according to the received signals, so as to drive the ball screw 4 to realize the precise lifting of the floating platform 10. The PLC controller controls the on and off of the coils of the intermediate relay KA5 and the intermediate relay KA6 respectively through its output ports Y10 and Y11. The normally open contacts of the intermediate relay KA5 and the intermediate relay KA6 are respectively connected to the two control circuits of the solenoid valve of the inkjet cylinder 13, so as to realize the control of the extension and retraction of the piston rod of the inkjet cylinder 13. The PLC controller controls the on and off of the coil of the intermediate relay KA2 through its output port Y5. The normally open contact of the intermediate relay KA2 is connected to the power supply circuit of the inkjet printer 14, so as to realize the start and stop control of the inkjet printer 14.

[0018] As a further improvement of the present invention, the PLC controller controls the on and off of the coil of the intermediate relay KA7 through its output port Y12. The normally open contact of the intermediate relay KA7 is connected to the electromagnetic coil circuit of the first water inlet valve V1, so as to realize the opening and closing control of the first water inlet valve V1. The PLC controller controls the on and off of the coil of the intermediate relay KA8 through its output port Y13. The normally open contact of the intermediate relay KA8 is connected to the electromagnetic coil circuit of the second water inlet valve V2, so as to realize the opening and closing control of the second water inlet valve V2. The PLC controller controls the on and off of the coil of the intermediate relay KA9 through its output port Y14. The normally open contact of the intermediate relay KA9 is connected to the electromagnetic coil circuit of the drain valve V3, so as to realize the opening and closing control of the drain valve V3.

[0019] Another object of the present invention is to overcome the problems existing in the prior art, and provide a method for quantitatively calibrating the scale of a burette, which can accurately calibrate the scale on the outer wall of the burette, reduce errors, improve product quality, and reduce labor intensity.

[0020] To solve the above technical problems, a method for quantitatively calibrating the scale of a burette according to the present invention uses a burette liquid level scale calibrating machine, and successively includes the following steps: S1: In the semi-automatic mode, start the equipment, open the first water inlet valve V1, and the purified water in the water tank 23 enters the syringe 25. When the water volume in the syringe 25 reaches the preset full water value, the full water mark induction switch SQ3 sends a signal, and the first water inlet valve V1 is closed; S2: After a delay, open the second water inlet valve V2, and the water in the syringe 25 is injected into the glass tube 7. When the water level in the glass tube 7 reaches the lower preset position, the initial water level induction switch SQ2 sends a signal, and the second water inlet valve V2 is closed; S3: Open the first water inlet valve V1, and the purified water in the water tank 23 enters the syringe 25 again through the first water inlet valve V1. When the water volume in the syringe 25 reaches the preset full water value, the full water mark induction switch SQ3 sends a signal, and the first water inlet valve V1 is closed; S4: The servo motor 3 drives the ball screw 4 to rotate forward, driving the floating platform 10 to rise. After rising a short distance above the liquid level, the ball screw 4 rotates in reverse, driving the floating platform 10 to descend. When the photoelectric switch SQ4 detects the liquid level, the servo motor 3 stops; S5: The piston rod of the inkjet cylinder 13 extends, pushing the inkjet printer 14 close to the glass tube 7, and then inkjet printing is performed to spray scale lines on the outer wall of the glass tube 7; S6: The piston rod of the inkjet cylinder 13 contracts, and the inkjet printer 14 retracts and stops at the rear limit; S7: Open the second water inlet valve V2. After all the water in the syringe 25 enters the glass tube 7, the second water inlet valve V2 is closed; S8: Open the first water inlet valve V1, and the purified water in the water tank 23 enters the syringe 25 again through the first water inlet valve V1. When the water volume in the syringe 25 reaches the preset full water value, the full water mark induction switch SQ3 sends a signal, and the first water inlet valve V1 is closed; S9: The servo motor 3 drives the ball screw 4 to rotate forward, driving the floating platform 10 to rise. After rising a short distance above the liquid level, the ball screw 4 rotates in reverse, driving the floating platform 10 to descend. When the photoelectric switch SQ4 detects the liquid level, the servo motor 3 stops; S10: The piston rod of the inkjet cylinder 13 extends, pushing the inkjet printer 14 close to the glass tube 7, and then inkjet printing is performed to spray scale lines on the outer wall of the glass tube 7; S11: The piston rod of the inkjet cylinder 13 contracts, and the inkjet printer 14 retracts, and stops retracting when it reaches the rear limit position.

[0021] Further, it also includes S12: Repeat steps S7 to S11, and calibrate multiple scale points in sequence according to the capacity of the burette; For a 50 ml burette, calibrate two scale points of 0 ml and 50 ml; for a 100 ml burette, calibrate three scale points of 0 ml, 50 ml and 100 ml.

[0022] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. Completely abandon manual visual calibration and realize automated production. The present invention no longer relies on manual visual observation for the volume calibration of the burette, and completely eliminates the calibration errors caused by operator visual fatigue, lack of experience or individual differences. Through the automated control system and high-precision photoelectric detection technology, accurate calibration of the burette scale is realized, ensuring high consistency in the product quality of the same batch and different batches, greatly improving the yield rate of the products, and being able to meet the large market demand for high-precision burettes.

[0023] 2. High-precision liquid level detection and calibration. The present invention accurately controls the water injection volume of the syringe to ensure that the volume of purified water injected into the glass tube each time is accurate. At the same time, the through-beam photoelectric switch is used to detect the liquid level position, which can effectively eliminate the error influence caused by liquid level fluctuation and lead screw clearance, and accurately calibrate at the liquid level, significantly improving the accuracy and reliability of the burette scale.

[0024] 3. Significantly reduce labor intensity and protect the health of operators. The traditional manual calibration method has extremely high requirements for the eyesight and physical strength of operators. Long-term work is likely to cause eyesight decline and physical fatigue, thereby affecting product quality. The present invention completes the calibration work through automated equipment. Operators do not need to observe the small liquid level changes at close range for a long time, nor do they need to frequently adjust their postures, greatly reducing the labor intensity and avoiding damage to the eyesight and physical health of operators.

[0025] 4. Not affected by natural light and environmental factors. The photoelectric detection technology adopted by the present invention is not affected by the change of natural light intensity and can work stably under various lighting conditions. At the same time, the automated operation of the equipment is not interfered by external environmental factors (such as temperature, humidity, etc.), ensuring the stability and consistency of the calibration process.

[0026] 5. Realize large-scale production and improve production efficiency. Since the calibration process of the present invention is completely automated and no longer relies on the skill level of workers, large-scale production can be easily achieved. The equipment can quickly and accurately complete the scale calibration of the burette, significantly improving the production efficiency, reducing the production cost, and being able to meet the large market demand for high-precision burettes.

[0027] 6. Improve the stability of product quality. Through automated control and high-precision detection technology, the present invention can ensure that the calibration accuracy of the scale of each burette is consistent, avoiding the random errors caused by manual calibration. This makes the product quality more stable, effectively improving the application effect of the burette in fields such as chemical analysis and providing a strong guarantee for the accuracy of experimental results.

[0028] 7. Easy to operate and maintain. The burette liquid level scale calibration machine of the present invention adopts a modular design, with simple operation and convenient maintenance. The automated control system of the equipment has a friendly human-machine interface, and the operator can operate proficiently after simple training. At the same time, the equipment has low maintenance costs and a long service life, which can bring long-term economic benefits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. The drawings are only for reference and explanation, and are not used to limit the present invention. Among them: Figure 1 is the front view of the burette liquid level scale calibration machine of the present invention; Figure 2 is Figure 1 the top view of Figure 3 is Figure 1 the left view of Figure 4 is the three-dimensional view of the burette liquid level scale calibration machine of the present invention; Figure 5 is Figure 4 the enlarged view of the partial part; Figure 6 is the electrical principle Figure 1 ; Figure 7 is the electrical principle Figure 2 ; In the figure: 1. Workbench; 2. Frame; 3. Servo motor; 4. Ball screw; 5. Vertical guide rail; 6. Glass tube base; 7. Glass tube; 8. Glass tube support; 9. Glass tube clamp; 10. Floating platform; 11. Inkjet printing base; 12. Inkjet printing guide rail; 13. Inkjet printing cylinder; 14. Inkjet printer; 15. Cross slide base; 16. Cross slide guide rail; 17. Cross slide carriage; 18. Cross slide; 19. Cross slide adjusting screw rod; 20. Cross slide adjusting handwheel; 21. Opposite photoelectric switch support; 22. Control box; 23. Water tank; 24. Syringe support; 25. Syringe; 26. Weight V1. First water inlet valve; V2. Second water inlet valve; V3. Drain valve SQ1. Floating platform zero position sensor; SQ2. Initial water level induction switch; SQ3. Water full mark induction switch; SQ4. Photoelectric switch Specific embodiments

[0030] In the following description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating that the device must have a specific orientation.

[0031] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below with reference to specific drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0033] As Figures 1 to 5 shown, the burette liquid level scale calibration machine of the present invention includes a workbench 1. A frame 2 is erected upward at the rear side of the workbench 1. In the middle of the front end face of the frame 2, a ball screw 4 extending vertically is provided. The upper end of the ball screw 4 is driven by a servo motor 3, and the lower end of the ball screw 4 is supported by a bearing at the lower part of the front vertical face of the frame 2. On both sides of the front end face of the frame 2, vertical guide rails 5 are fixed. The two vertical guide rails 5 are symmetrically located on both sides of the ball screw 4. The rear ends of both sides of the floating platform 10 are respectively supported on the two vertical guide rails 5 through guide sliders; a Z-axis screw nut is engaged on the ball screw 4, and the Z-axis screw nut is connected to the middle part of the rear side of the floating platform 10. After the servo motor 3 is started, it drives the ball screw 4 to rotate, and the Z-axis screw nut rises and falls along the ball screw 4, driving the floating platform 10 to rise and fall smoothly along the two vertical guide rails 5.

[0034] A glass tube support 8 extending upward is fixed on the workbench 1. A glass tube clamp 9 is installed on the upper part of the glass tube support 8. A vertical long groove is provided along the axis of the glass tube support 8 to facilitate adjusting the height of the glass tube clamp 9. A glass tube base 6 is fixed on the front side of the glass tube support 8. Before calibration, the lower end of the glass tube 7 is inserted into the central hole of the glass tube base 6. The lower port of the glass tube 7 is provided with a reduced diameter for easy insertion. After insertion, the outer periphery of the glass tube 7 is sealed by a sealing ring. The upper end of the glass tube 7 is clamped by the glass tube clamp 9 to keep the glass tube 7 in a vertical state. The lower end of the glass tube 7 passes through the notch of the floating platform 10, and the reduced diameter section at the lower end of the glass tube 7 needs to be cut off later.

[0035] On one side of the glass tube base 6 (the right side in the figure), a drag plate base 15 fixed on the floating platform 10 is provided. A drag plate guide rail 16 extending in the left-right direction is provided on the drag plate base 15. The drag plate guide rail 16 is in the shape of a dovetail, and a drag plate slide 17 that translates left and right along it is provided on it. A drag plate 18 is fixed above the drag plate slide 17. Above the left end of the drag plate 18, an opposed photoelectric switch support 21 is fixed. The opposed photoelectric switch support 21 is in the shape of a C with an open left end to facilitate the glass tube 7 to be inserted. A pair of photoelectric switches are installed at the front and rear of the left end of the opposed photoelectric switch support 21. The two photoelectric switches are at the same height. The photoelectric switch on the front side of the glass tube emits a light beam backward along the horizontal plane, and the light beam passes through the center of the glass tube and is received by the photoelectric switch on the rear side of the glass tube.

[0036] The lower part of the drag plate slide 17 is connected to the drag plate adjusting screw 19 through a screw nut. The drag plate adjusting screw 19 extends in the left-right direction, and a drag plate adjusting handwheel 20 is fixed at the right end. Before the calibration operation, by rotating the drag plate adjusting handwheel 20, the drag plate adjusting screw 19 drives the drag plate slide 17 to translate along the drag plate guide rail 16, so that the drag plate 18 carries the opposed photoelectric switch support 21 to accurately adjust the position in the left-right direction, so that the light beam emitted by the front-side photoelectric switch accurately passes through the center line of the glass tube 7 backward and is received by the rear-side photoelectric switch SQ4. The center line of the glass tube 7 is the lowest point of its liquid level.

[0037] If the light beam emitted by the front-side photoelectric switch passes through above the liquid level of the glass tube 7, it can be received by the rear-side photoelectric switch. If the light beam emitted by the front-side photoelectric switch passes through below the liquid level of the glass tube 7, due to the refraction of light in water, it cannot be received by the rear-side photoelectric switch SQ4. The moment when the light beam changes from being able to be received to not being able to be received is the position of the liquid level.

[0038] On the other side of the glass tube base 6 (the left side in the figure), there is a coding base 11 fixed on the floating platform 10. On the coding base 11, there is a coding guide rail 12 extending in the left-right direction. On the coding guide rail 12, there is a coder 14 that translates left and right along it. The nozzle of the coder 14 and the light beam emitted by the front photoelectric switch are on the same horizontal plane. On the outside of the coding base 11, a coding cylinder 13 is fixed. The free end of the piston rod of the coding cylinder 13 is connected to the coder 14.

[0039] When the photoelectric switch finds the liquid level, the floating platform 10 stops. The piston rod of the coding cylinder 13 extends, driving the coder 14 to translate right along the coding guide rail 12, making the nozzle of the coder 14 close to the outer wall of the glass tube and completing the coding, which is a "one"-shaped scale line.

[0040] On the workbench 1, there is also a syringe support 24 extending upward. The syringe support 24 is located in front of one side of the frame 2. At the upper part of the syringe support 24, a syringe 25 is fixed. The syringe barrel of the syringe 25 faces downward, and the piston of the syringe 25 faces upward. And on the top of the syringe piston, there is a 1 kg weight 26, which is convenient for automatically pushing the piston to move downward.

[0041] On the outside of the workbench 1, there is a control box 22 and a water tank 23. The bottom outlet of the water tank 23 is connected to the inlet of the first water inlet valve V1 through a water supply pipe. The outlet of the first water inlet valve V1 is connected to one side inlet of a tee. The middle outlet of the tee is connected to the syringe barrel outlet of the syringe 25 through a water injection pipe. The other side outlet of the tee is connected to the inlet of the second water inlet valve V2. The outlet of the second water inlet valve V2 is connected to the water injection port on the side wall of the glass tube base 6 through a water injection pipe. At the center of the bottom of the glass tube base 6, there is a drain pipe connected and a drain valve V3 is installed.

[0042] In the initial state, the first water inlet valve V1, the second water inlet valve V2 and the drain valve V3 are all closed. When the first water inlet valve V1 is opened, the water tank 23 fills the syringe 25 with water. When the first water inlet valve V1 is closed and the second water inlet valve V2 is opened, the water injector injects water into the glass tube 7. When the first water inlet valve V1 and the second water inlet valve V2 are closed and the drain valve V3 is opened, the water in the glass tube 7 is drained.

[0043] At the upper part of the syringe support 24, an initial water level induction switch SQ2 is also installed, which is used to monitor the water level in the syringe 25. In the initial state, when the second water inlet valve V2 is opened to inject a small amount of water into the glass tube 7, when the water injection pipe filled with water at the outlet of the second water inlet valve V2 enters the lower part of the glass tube 7 and reaches the position to be calibrated, the initial water level induction switch SQ2 sends a signal to close the second water inlet valve V2. The glass tube section below the position to be calibrated is the non-calibrated tube section or the non-working tube section.

[0044] Such as Figure 6 、 Figure 7As shown in the figure, the control system in the control box 22 mainly includes a Mitsubishi servo controller MR-J2S-200A and a Mitsubishi PLC controller FX1S-30MT. The hand / automatic changeover button SA1 is connected between the X0 port and the COM of the PLC controller, and the start button SB1 is connected between the X1 port and the COM of the PLC controller; the manual upward button SB2 is connected between the X2 port and the COM of the PLC controller to manually control the upward movement of the floating platform 10; the manual downward button SB3 is connected between the X3 port and the COM of the PLC controller to manually control the downward movement of the floating platform 10.

[0045] The coil of the intermediate relay KA1 is connected between the Y4 port of the PLC controller and 24VDC. The normally open contact of the intermediate relay KA1 is connected between the SON port and the SG port of the servo controller. When the Y4 port of the PLC controller energizes the coil of the intermediate relay KA1, the normally open contact of the intermediate relay KA1 closes, and the servo controller starts.

[0046] The zero-finding button SB4 is connected between the X4 port and the COM of the PLC controller. A floating platform zero-position sensor SQ1 is installed at the lower part of the frame 2 to detect the zero-position height of the lead screw nut and the floating platform 10. The signal terminal of the floating platform zero-position sensor SQ1 is connected to the X12 port of the PLC controller. The positive pole of the floating platform zero-position sensor SQ1 is connected to 24VDC, and the negative pole is connected to 0V. Each time the machine is powered on, pressing the zero-finding button SB4 sends a signal, and the servo motor 3 drives to calibrate the zero position of the ball screw 4. When the floating platform 10 reaches the zero position, the floating platform zero-position sensor SQ1 sends a signal, and the ball screw 4 stops. This facilitates the consistency of glass tube batch production and avoids the deviation of the position of the floating platform 10 caused by cumulative errors.

[0047] The coil of the intermediate relay KA10 is connected between the ALM port and the COM port of the servo controller. At the same time, the COM terminal and the VDD terminal are short-circuited. The normally open contact of the intermediate relay KA10 is connected between the X6 port and the COM of the PLC controller to send the servo alarm signal to the PLC controller.

[0048] The emergency stop button SB0 is connected between the X7 port and the COM of the PLC controller for overall shutdown in case of emergency.

[0049] The X10 port of the PLC controller receives the signal that the servo motor 3 has run in place. This signal is sent from the INP port of the servo controller to control subsequent execution actions.

[0050] The coil of the intermediate relay KA2 is connected between the Y5 port of the PLC controller and 24VDC. When coding is required, the PLC controller outputs a signal to make the intermediate relay KA2 pull in, turning on the power supply of the coder 14, and the coder 14 starts to work, spraying a "one"-shaped scale line on the glass tube. After the coding is completed, the PLC controller cuts off the signal, the intermediate relay KA2 releases, and the coder 14 stops working.

[0051] The coil of the intermediate relay KA3 is connected between the Y6 port of the PLC controller and 24VDC. The normally open contact of the intermediate relay KA3 is connected between the EMG port and the SG port of the servo controller for the emergency stop of the servo motor 3.

[0052] The coil of the intermediate relay KA5 is connected between the Y10 port of the PLC controller and 24VDC. When coding is required, the PLC controller outputs a signal to make the intermediate relay KA5 pull in, turning on the extension circuit of the coding cylinder 13, controlling the piston rod of the coding cylinder 13 to extend, and driving the coder 14 close to the glass tube.

[0053] The coil of the intermediate relay KA6 is connected between the Y11 port of the PLC controller and 24VDC. After the coding is completed, the PLC controller outputs a signal to make the intermediate relay KA6 pull in, turning on the retraction circuit of the coding cylinder 13, controlling the piston rod of the coding cylinder 13 to retract, and driving the coder 14 to retract.

[0054] The coil of the intermediate relay KA7 is connected between the Y12 port of the PLC controller and 24VDC to control the opening and closing of the first water inlet valve V1. When water needs to be injected into the syringe 25, the PLC controller outputs a signal to make the intermediate relay KA7 pull in, turning on the power supply of the electromagnetic coil of the first water inlet valve V1, and the first water inlet valve V1 opens, and the water in the water tank 23 flows into the syringe 25; when the syringe 25 reaches the preset water volume, the PLC controller cuts off the signal, the intermediate relay KA7 releases, and the first water inlet valve V1 closes.

[0055] The coil of the intermediate relay KA8 is connected between the Y13 port of the PLC controller and 24VDC to control the opening and closing of the second water inlet valve V2. When water needs to be injected into the glass tube 7, the PLC controller outputs a signal to make the intermediate relay KA8 pull in, turning on the power supply of the electromagnetic coil of the second water inlet valve V2, and the second water inlet valve V2 opens, and the water in the syringe 25 flows into the glass tube 7; after completion, the PLC controller cuts off the signal, the intermediate relay KA8 releases, and the second water inlet valve V2 closes.

[0056] The coil of the intermediate relay KA9 is connected between the Y14 port of the PLC controller and 24VDC to control the opening and closing of the drain valve V3. When it is necessary to drain the water in the glass tube 7, the PLC controller outputs a signal to make the intermediate relay KA9 pull in, connecting the power supply of the electromagnetic coil of the drain valve V3, and the drain valve V3 opens to drain the water in the glass tube 7. After the drainage delay time arrives, the PLC controller cuts off the signal, the intermediate relay KA9 releases, and the drain valve V3 closes.

[0057] The signal terminal of the initial water level induction switch SQ2 is connected to the X13 port of the PLC controller. After the syringe 25 drops to a certain water level, the initial water level induction switch SQ2 sends a signal to the X13 port of the PLC controller to close the second water inlet valve V2. At this time, the injected water volume fills the water injection pipe and enters the lower part of the glass tube at the initial position to be calibrated.

[0058] The signal terminal of the full water level indicator switch SQ3 is connected to the X14 port of the PLC controller. When the water volume in the syringe 25 reaches 50 ml, the full water level indicator switch SQ3 sends a signal to close the first water inlet valve V1, so that the syringe 25 accurately maintains a water volume of 50 ml.

[0059] The signal terminal of the photoelectric switch SQ4 on the receiving side is connected to the X15 port of the PLC controller. When the floating platform 10 is rising, the liquid level calibration limit switch SQ4 detects the liquid level and sends a signal, but at this time the signal is blocked in the logic program of the PLC controller.

[0060] When the floating platform 10 crosses the liquid level upward and then detects the liquid level downward, the liquid level calibration limit switch SQ4 sends a signal, and the signal is transmitted to the PLC controller. Through logic control, the servo motor 3 and the ball screw 4 stop, and the floating platform 10 is fixed, ready for inkjet coding.

[0061] The 380V power supply is connected to the power supply ports L1 - L3 of the Mitsubishi servo controller MR - J2S - 200A through the fast fuse FU1 and the normally open contact of the AC contactor 1KM to supply power to the servo controller. The L11 and L21 of the servo controller are connected to control the power supply. The motor output ports U, V, W of the servo controller are connected to the power supply ports of the servo motor 3 to control the operation of the servo motor 3.

[0062] The coil of the intermediate relay KA4 is connected between the Y7 port of the PLC controller and 24VDC. The normally open contact of the intermediate relay KA4 is connected in series with the coil of the AC contactor 1KM between L33 and N to realize the power - on enable control of the servo controller through the PLC controller.

[0063] The Y2 port of the PLC controller sends the forward and reverse signals of the ball screw 4 to the NP port of the servo controller to control the rotation direction of the servo motor 3; The YO port of the PLC controller sends the lifting pulse signal of the ball screw 4 to the PP port of the servo controller to control the stroke of the servo motor 3; When the ball screw 4 pulls the floating platform 10 to lift in place, the INP port of the servo controller feeds back the in-place signal to the X10 port of the PLC controller.

[0064] The reset button SB5 is connected between the RES port of the servo controller and SG; during the servo operation, soft limit control is adopted, and the external hard limit function is not used, so the forward limit port LSP and the reverse limit port LSN are short-circuited with SG.

[0065] The quantitative scale calibration of the burette liquid level calibrator sequentially includes the following steps: S1. In the "semi-automatic" state, after pressing the start button, the first water inlet valve V1 opens, and the purified water in the water tank 23 enters the syringe 25 due to potential energy through the first water inlet valve V1, pushing the syringe plunger upward. When the syringe 25 reaches 50 ml, it is in the full water state. At this time, the full water mark induction switch SQ3 sends a signal, and the first water inlet valve V1 closes; S2. After a delay of 0.2 seconds, the second water inlet valve V2 opens, and the water in the syringe 25 enters the glass tube 7 to be processed through the second water inlet valve V2 and the connecting pipeline. When the water level in the glass tube 7 reaches the "zero position" at the lower part of the glass tube, the initial water level induction switch SQ2 on one side of the syringe 25 sends a signal, and the second water inlet valve V2 closes; S3. The first water inlet valve V1 opens, and the purified water in the water tank 23 enters the syringe 25 again through the first water inlet valve V1. When it reaches 50 ml, it is in the full water state. At this time, the full water mark induction switch SQ3 sends a signal, and the first water inlet valve V1 closes; S4. The servo motor 3 drives the ball screw 4 to rotate forward, the lead screw nut drives the floating platform 10 to rise, the floating platform 10 drives the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move upward. After rising a short distance above the liquid level, the ball screw 4 rotates reversely, driving the floating platform 10, the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move slowly downward, so as to eliminate the error caused by the screw clearance. When the photoelectric switch SQ4 reaches the concave surface of the liquid level, it sends a signal, and the servo motor 3 and the ball screw 4 stop, and the floating platform 10 is fixed; S5. The piston rod of the inkjet cylinder 13 extends, pushing the inkjet printer 14 close to the glass tube 7, and then inkjet printing is performed, spraying a "one"-shaped scale line corresponding to 0 ml on the outer wall of the glass tube 7; S6. After a delay of several seconds, the piston rod of the inkjet cylinder 13 contracts, and the inkjet printer 14 retracts and stops at the rear limit; S7. The second water inlet valve V2 is opened, and the water in the syringe 25 enters the glass tube 7. After a certain delay until all 50 ml of water has entered the glass tube 7, the second water inlet valve V2 is closed; S8. The first water inlet valve V1 is opened, and the purified water in the water tank 23 enters the syringe 25 again through the first water inlet valve V1. When it reaches 50 ml, it is full of water. At this time, the water full flag induction switch SQ3 sends a signal, and the first water inlet valve V1 is closed; S9. The servo motor 3 drives the ball screw 4 to rotate forward. The screw nut drives the floating platform 10 to rise. The floating platform 10 drives the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move upward. After rising a short distance above the liquid level, the ball screw 4 rotates in the reverse direction, driving the floating platform 10, the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move slowly downward. When the photoelectric switch SQ4 on the receiving side sends a signal, the servo motor 3 and the ball screw 4 stop; S10. The piston rod of the inkjet cylinder 13 extends, pushing the inkjet printer 14 close to the glass tube 7, and then inkjet printing is carried out to spray a "one"-shaped scale line corresponding to 50 ml on the outer wall of the glass tube 7; S11. After a few seconds of delay, the piston rod of the inkjet cylinder 13 contracts, and the inkjet printer 14 retracts and stops at the rear limit; For the burette with a capacity of 50 ml, the calibration work is completed, and it jumps to step S12. For the burette with a capacity of 50 ml, continue with the following steps: S12. The second water inlet valve V2 is opened, and the water in the syringe 25 enters the glass tube 7. After a certain delay until all 50 ml of water has entered the glass tube 7, the second water inlet valve V2 is closed; S13. The first water inlet valve V1 is opened, and the purified water in the water tank 23 enters the syringe 25 again through the first water inlet valve V1. When it reaches 50 ml, it is full of water. At this time, the water full flag induction switch SQ3 sends a signal, and the first water inlet valve V1 is closed; S14. The servo motor 3 drives the ball screw 4 to rotate forward. The screw nut drives the floating platform 10 to rise. The floating platform 10 drives the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move upward. After rising a short distance above the liquid level, the ball screw 4 rotates in the reverse direction, driving the floating platform 10, the inkjet printer 14 and the opposed photoelectric switch bracket 21 to move slowly downward. When the photoelectric switch SQ4 on the receiving side sends a signal, the servo motor 3 and the ball screw 4 stop; S15. The piston rod of the inkjet cylinder 13 extends, pushing the inkjet printer 14 close to the glass tube 7, and then inkjet printing is carried out to spray a "one"-shaped scale line corresponding to 100 ml on the outer wall of the glass tube 7; S16. After a few seconds of delay, the piston rod of the inkjet cylinder 13 contracts, and the inkjet printer 14 retracts and stops at the rear limit; S17. The drain valve V3 is opened to drain the water in the burette. Thus, the capacity calibration of one glass tube is completed. Next, operations such as printing and drying the scales will be carried out according to the calibration lines.

[0066] The above is only the preferred and feasible embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention. It is not intended to limit the patent protection scope of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. Except for the above embodiments, without departing from the spirit and scope of the present invention, the present invention may have other implementation manners. The present invention will also have various changes and improvements. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention. The protection scope required by the present invention is defined by the appended claims and their equivalents. The technical features not described in the present invention can be realized by or adopted the prior art, which will not be elaborated here.

Claims

1. A burette liquid level scale calibration machine, characterized in that, Comprising: Workbench (1); Frame (2), fixed to the rear side of the workbench (1), a ball screw (4) extending vertically is provided in the middle of the front end face of the frame (2), the upper end of the ball screw (4) is driven by a servo motor (3), and the servo motor (3) is fixed to the top of the frame (2); Vertical guide rails (5), symmetrically arranged on both sides of the ball screw (4), fixed to the front end face of the frame (2); Floating platform (10), the two ends of the rear side thereof are supported on the vertical guide rails (5) through guiding sliders, and the middle part of the rear side of the floating platform (10) is connected to the lead screw nut on the ball screw (4); Glass tube support (8), fixed to the workbench (1), for supporting the glass tube (7); Inkjet printer (14), installed on the floating platform (10), for jet-printing calibration lines on the outer wall of the glass tube (7); Syringe (25), for injecting purified water into the glass tube (7).

2. The burette liquid level scale calibration machine according to claim 1, wherein: A pair of photoelectric switch brackets (21) are also fixed on the floating platform (10), and a pair of photoelectric switches are installed on the pair of photoelectric switch brackets (21), for detecting the liquid level position in the glass tube (7) and sending signals to the control system.

3. The burette liquid level scale calibration machine according to claim 2, wherein, Also comprising: Carriage base (15), fixed to the floating platform (10), a carriage guide rail (16) extending in the left-right direction is provided on the carriage base (15); Carriage slide (17), translating left and right along the carriage guide rail (16), a carriage (18) is fixed above the carriage slide (17), and the pair of photoelectric switch brackets (21) are installed at one end of the carriage (18); Carriage adjustment lead screw (19), engaged with a carriage lead screw nut, the carriage lead screw nut is connected to the carriage slide (17), for adjusting the position of the pair of photoelectric switch brackets (21) so that the photoelectric switch passes through the center of the glass tube; Carriage adjustment handwheel (20), fixed to the end of the carriage adjustment lead screw (19), for manually adjusting the carriage adjustment lead screw (19).

4. The burette liquid level scale calibration machine according to claim 1, characterized in that, An inkjet base (11) is fixed on the floating platform (10), an inkjet guide rail (12) extending in the left-right direction is provided on the top of the inkjet base (11), the bottom of the inkjet printer (14) is supported on the inkjet guide rail (12), an inkjet cylinder (13) is installed at the outer end of the inkjet base (11), the piston rod of the inkjet cylinder (13) drives the inkjet printer (14) to translate left and right along the inkjet guide rail (12), and the inkjet printer (14) and the pair of photoelectric switch brackets (21) are respectively located on the left and right sides of the glass tube.

5. The burette liquid level calibration machine according to claim 1, characterized in that, A glass tube base (6) is provided on the front side of the glass tube support (8), the glass tube base (6) is fixed to the workbench (1), the lower end of the glass tube (7) is inserted into the glass tube base (6) and sealed; a glass tube clamp (9) is installed on the upper part of the glass tube support (8), and the glass tube clamp (9) clamps the upper part of the glass tube (7) to keep it in a vertical state; a vertical long groove is provided along the axis of the glass tube support (8) to adjust the height of the glass tube clamp (9).

6. The burette liquid level scale calibration machine according to claim 5, characterized in that, On the said workbench (1), there is also fixedly installed a syringe support (24) extending upwards. The syringe (25) is fixed to the upper part of the syringe support (24) with the syringe barrel facing downwards, and a weight (26) for pushing it downwards is pressed on the top of the piston rod of the syringe (25); outside the workbench (1), there is a water tank (23) higher than the syringe (25). The outlet of the water tank (23) is connected to the inlet of the first water inlet valve (V1) through a water supply pipe. The outlet of the first water inlet valve (V1) is connected to the inlet of the second water inlet valve (V2) and the syringe (25) respectively through a tee. The second water inlet valve (V2) is connected to the side wall inlet of the glass tube base (6) through an injection water pipe, and the glass tube base (6) is connected with a drain valve (V3).

7. The burette liquid level scale calibration machine according to claim 2, characterized in that, The said control system includes a Mitsubishi servo controller (MR-J2S-200A) and a Mitsubishi PLC controller (FX1S-30MT), and the PLC controller is communicatively connected with the servo controller; The PLC controller sends pulse signals and direction control signals to the servo controller through its output ports (Y0 and Y2). The servo controller controls the forward and reverse rotation and speed of the servo motor (3) according to the received signals, so as to drive the ball screw (4) to realize the precise lifting of the floating platform (10); The PLC controller controls the on-off of the coils of the intermediate relay KA5 and the intermediate relay KA6 respectively through its output ports (Y10 and Y11). The normally open contacts of the intermediate relay KA5 and the intermediate relay KA6 are respectively connected to the two control circuits of the solenoid valve of the inkjet cylinder (13) to realize the control of the extension and retraction of the piston rod of the inkjet cylinder (13); The PLC controller controls the on-off of the coil of the intermediate relay KA2 through its output port (Y5). The normally open contact of the intermediate relay KA2 is connected to the power supply circuit of the inkjet printer (14) to realize the start-stop control of the inkjet printer (14).

8. The burette liquid level scale calibration machine according to claim 7, characterized in that, The PLC controller controls the on-off of the coil of the intermediate relay KA7 through its output port (Y12). The normally open contact of the intermediate relay KA7 is connected to the electromagnetic coil circuit of the first water inlet valve (V1) to realize the opening and closing control of the first water inlet valve (V1); The PLC controller controls the on-off of the coil of the intermediate relay KA8 through its output port (Y13). The normally open contact of the intermediate relay KA8 is connected to the electromagnetic coil circuit of the second water inlet valve (V2) to realize the opening and closing control of the second water inlet valve (V2); The PLC controller controls the on-off of the coil of the intermediate relay KA9 through its output port (Y14). The normally open contact of the intermediate relay KA9 is connected to the electromagnetic coil circuit of the drain valve (V3) to realize the opening and closing control of the drain valve (V3).

9. A method for calibrating the quantitative scale of a burette, characterized in that, Adopting the burette liquid level scale calibration machine as described in any one of claims 1-8, it successively includes the following steps: S1: In the semi-automatic mode, start the device. The first water inlet valve (V1) opens, and the purified water in the water tank (23) enters the syringe (25). When the water volume in the syringe (25) reaches the full-water preset value, the full-water mark induction switch (SQ3) sends a signal to close the first water inlet valve (V1). S2: After a delay, the second water inlet valve (V2) opens, and the water in the syringe (25) is injected into the glass tube (7). When the water level in the glass tube (7) reaches the lower preset position, the initial water level induction switch (SQ2) sends a signal to close the second water inlet valve (V2). S3: The first water inlet valve (V1) opens, and the purified water in the water tank (23) enters the syringe (25) again through the first water inlet valve (V1). When the water volume in the syringe (25) reaches the full-water preset value, the full-water mark induction switch (SQ3) sends a signal to close the first water inlet valve (V1). S4: The servo motor (3) drives the ball screw (4) to rotate forward, driving the floating platform (10) to rise. After rising a short distance above the liquid level, the ball screw (4) rotates in reverse, driving the floating platform (10) to descend. When the photoelectric switch (SQ4) detects the liquid level, the servo motor (3) stops. S5: The piston rod of the inkjet cylinder (13) extends, pushing the inkjet printer (14) close to the glass tube (7), and then inkjet printing is performed to spray scale lines on the outer wall of the glass tube (7). S6: The piston rod of the inkjet cylinder (13) retracts, and the inkjet printer (14) retracts and stops at the rear limit position. S7: The second water inlet valve (V2) opens. After all the water in the syringe (25) enters the glass tube (7), the second water inlet valve (V2) closes. S8: The first water inlet valve (V1) opens, and the purified water in the water tank (23) enters the syringe (25) again through the first water inlet valve (V1). When the water volume in the syringe (25) reaches the full-water preset value, the full-water mark induction switch (SQ3) sends a signal to close the first water inlet valve (V1). S9: The servo motor (3) drives the ball screw (4) to rotate forward, driving the floating platform (10) to rise. After rising a short distance above the liquid level, the ball screw (4) rotates in reverse, driving the floating platform (10) to descend. When the photoelectric switch (SQ4) detects the liquid level, the servo motor (3) stops. S10: The piston rod of the inkjet cylinder (13) extends, pushing the inkjet printer (14) close to the glass tube (7), and then inkjet printing is performed to spray scale lines on the outer wall of the glass tube (7). S11: The piston rod of the inkjet cylinder (13) retracts, and the inkjet printer (14) retracts and stops at the rear limit position.

10. The burette liquid level scale calibrator according to claim 9, wherein S12: Repeat steps S7 to S11, and calibrate multiple scale points in sequence according to the capacity of the burette; For a 50 ml burette, calibrate two scale points of 0 ml and 50 ml; for a 100 ml burette, calibrate three scale points of 0 ml, 50 ml and 100 ml.

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