Calibration device for variable viscosity gear flowmeter

Abstract

A variable-viscosity gear flowmeter calibration device comprises a measurement module, a low-temperature calibration line and a high-temperature calibration line, the low-temperature calibration line and the high-temperature calibration line each comprise a piston cylinder, an oil inlet and an oil outlet are formed in each piston cylinder, a reciprocating piston rod is arranged in each piston cylinder, the left limit of each piston rod is located on the inner side of the corresponding oil inlet, and the right limit of each piston rod is located on the inner side of the corresponding oil outlet. The right limit of the piston rod is positioned on the outer side of the oil outlet; the low-temperature calibration line further comprises a cold insulation container and a heat insulation container, outlets of the cold insulation container and the heat insulation container are connected to oil inlets of the corresponding piston cylinders respectively, oil outlets of the piston cylinders are connected with corresponding measuring pipelines respectively, and a detected flowmeter, a viscosity sensor, a temperature sensor and a pressure sensor are arranged on the measuring pipelines. The measuring module comprises a microcontroller and a piston rod driving assembly. According to the gear flowmeter calibration device with the variable viscosity, two calibration lines can be adopted for calibration according to the use environment of a gear flowmeter and the difference of high-temperature liquid and low-temperature liquid, the accuracy in the calibration process is improved, and accurate calibration of the gear flowmeter is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flow meter calibration, and in particular relates to a calibration device for a gear flow meter with variable viscosity. Background Art

[0002] The gear flowmeter is a volumetric flowmeter consisting of a housing, a cover, a measuring gear, a preamplifier, a connector, a sensor and bearings.

[0003] The two measuring gears and the cavity each constitute a fixed volume. The measurement of liquid flow by the gear flowmeter is to calculate the number of standard metering volumes within a certain period of time. During the measurement process, a permanent magnet is installed inside a pair of meshing measuring gears. When the measured liquid pushes the measuring gear to rotate one tooth, the contactless sensor installed in the cover plate sends a pulse signal (a non-magnetic pressure-resistant partition is installed between the metering chamber and the sensor chamber). The preamplifier amplifies, rectifies, filters, multiplies the received pulse signal, and then outputs a regular square wave pulse signal, which ultimately generates a square wave number proportional to the flow rate, thereby measuring the volume flow value of the measured liquid. Compared with other flowmeters, gear flowmeters are safer, more reliable, and can work in harsh environments. Therefore, they are often used to measure flow velocity or flow in automobiles, aerospace, chemicals, organic liquids, etc. However, there is leakage in the calibration of gear flowmeters, which is greatly affected by pressure and liquid viscosity, so it is difficult to accurately measure liquid flow in practical applications. Therefore, effective calibration of gear flowmeters is very important for production, use, trade settlement, legal management, etc.

[0004] The technical solution provided by the patent "A device for visualizing small oil flow based on a gear flowmeter" has the following problems: the flow range is small and it cannot overcome the measurement inaccuracy caused by leakage, viscosity, and pressure changes of the gear flowmeter.

[0005] At the same time, the existing gear flowmeter can be calibrated during calibration, but the flowmeter for low-temperature lubricating oil and the flowmeter for high-temperature lubricating oil are often mixed together for measurement. If high-temperature lubricating oil is encountered, the heating mode will be turned on. When the flow of low-temperature lubricating oil is measured, the flowmeter calibrated in the high-temperature mode is used. During the detection process, due to the different viscosities of high-temperature liquid and low-temperature liquid, the flow rate of the liquid itself will be different, and the error and uncertainty of the flowmeter at high temperature and low temperature points will also be different. Therefore, the current mixed use of the two will undoubtedly increase the measurement error. Utility Model Content

[0006] The utility model aims to provide a calibration device for a gear flowmeter with variable viscosity, which has a simple structure and good use effect.

[0007] In order to solve the above technical problems, the utility model provides the following technical solutions: a calibration device for a gear flowmeter with variable viscosity, comprising a measuring module, a low-temperature calibration line and a high-temperature calibration line, wherein the low-temperature calibration line and the high-temperature calibration line both comprise a piston cylinder, an oil inlet and an oil outlet are provided on the piston cylinder, a piston rod which reciprocates is provided in the piston cylinder, a left limit of the piston rod is located on the inner side of the oil inlet, and a right limit of the piston rod is located on the outer side of the oil outlet; the low-temperature calibration line also comprises a cold-keeping container, and the low-temperature calibration line also comprises a heat-keeping container, the outlets of the cold-keeping container and the heat-keeping container are respectively connected to the oil inlet of the corresponding piston cylinder, the oil outlet of the piston cylinder is respectively connected to the corresponding measuring pipeline, the measuring pipeline is provided with a flowmeter to be tested, a viscosity sensor, a temperature sensor and a pressure sensor, the measuring module comprises a microcontroller and a piston rod drive assembly, the signal output ends of the viscosity sensor, the temperature sensor and the pressure sensor are connected to the signal input end of the microcontroller, the signal output end of the microcontroller outputs a signal connected to the piston rod drive assembly, and the piston rod drive assembly drives the movement of the piston rod.

[0008] Furthermore, in the calibration device for a gear flowmeter with variable viscosity provided by the utility model, both the cold-keeping container and the heat-keeping container are connected to the oil inlet of the corresponding piston cylinder through an oil pump.

[0009] Furthermore, in the calibration device for a gear flowmeter with a variable viscosity provided by the utility model, a cold-keeping interlayer is provided on the side wall of the cold-keeping container, and a heat-keeping interlayer is provided on the side wall of the heat-keeping container.

[0010] Furthermore, in the calibration device for a variable viscosity gear flowmeter provided by the utility model, the piston rod drive assembly includes a motor, a lead screw and a grating displacement sensor for collecting the movement of the piston rod, the signal output end of the grating displacement sensor is connected to the signal input end of the microcontroller, the motor drives the lead screw to rotate, a nut is threaded on the lead screw, and the nut drives the piston rod to reciprocate.

[0011] Furthermore, in the calibration device for a variable viscosity gear flowmeter provided by the utility model, a steam purge component is also provided on the measuring pipeline, and the steam purge component includes a steam generator.

[0012] Furthermore, in the calibration device for a variable viscosity gear flowmeter provided by the utility model, the outlet of the steam generator is connected to the measuring pipeline.

[0013] Furthermore, in the calibration device for a variable viscosity gear flowmeter provided by the utility model, the steam generator outlet is connected to the heat preservation interlayer inlet and the measuring pipeline through two steam pipelines respectively, and solenoid valves are provided on both steam pipelines, and the microcontroller outputs signals to control the closing and opening of the solenoid valves.

[0014] Furthermore, in the calibration device for a variable viscosity gear flowmeter provided by the utility model, the cold-keeping interlayer is filled with liquid nitrogen.

[0015] Through the above technical scheme, the beneficial effects of the utility model are as follows: 1. The utility model provides a calibration device for a gear flowmeter with variable viscosity. According to the use environment of the gear flowmeter and the difference between high-temperature liquid and low-temperature liquid, two calibration lines can be used for calibration, thereby improving the accuracy during the calibration process and realizing precise calibration of the gear flowmeter; 2. This scheme calibrates the flowmeter by setting a piston drive assembly and comparing the displacement of the piston and the capacity of the piston with the flow value, which is easy to use; 3. By connecting the heat preservation interlayer with the steam generator, the heating speed of the heat preservation container is increased, thereby increasing the calibration speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural schematic diagram of Example 1;

[0017] Figure 2 This is the principle block diagram of the utility model;

[0018] Figure 3 It is a schematic diagram of the structure of the piston drive assembly;

[0019] Figure 4 This is the circuit schematic diagram of the measurement module;

[0020] Figure 5 This is a schematic diagram of the structure of Example 2;

[0021] Figure 6 Schematic diagram of the heat preservation container structure. DETAILED DESCRIPTION

[0022] Embodiment 1, as Figures 1 to 4 As shown, the calibration device for the variable viscosity gear flowmeter includes a measuring module 12, a low temperature calibration line and a high temperature calibration line. The two calibration lines can be used to calibrate the high temperature liquid and low temperature liquid flowmeters respectively, thereby ensuring the accuracy of the calibration.

[0023] Both the low temperature calibration line and the high temperature calibration line include a piston cylinder, an oil inlet and an oil outlet are provided on the piston cylinder, a reciprocating piston rod is provided in the piston cylinder, the left limit of the piston rod is located on the inner side of the oil inlet, and the right limit of the piston rod is located on the outer side of the oil outlet; the low temperature calibration line also includes a cold-keeping container, and the low temperature calibration line preferably includes a heat-keeping container, the outlets of the cold-keeping container and the heat-keeping container are respectively connected to the oil inlet of the corresponding piston cylinder, and the oil outlet of the piston cylinder is respectively connected to the corresponding measuring pipeline,

[0024] Both the low temperature calibration line and the high temperature calibration line include a container, a piston cylinder 13, a measuring pipeline 11 and a piston rod drive assembly 9. The two calibration lines differ in that the container used for the high temperature liquid flow meter calibration is a heat preservation container 2, while the container used for the low temperature liquid flow meter calibration is a cold preservation container 1.

[0025] The heat preservation container 2 can achieve heating on the one hand and avoid heat loss on the other hand. The structure of the heat preservation container 2 is as follows: a heat preservation interlayer 19 is provided on the side wall of the heat preservation container 2. At the same time, an electric heating wire is provided on the inner wall of the heat preservation container 2. The heat preservation container 2 can be heated by the electric heating wire to ensure that the temperature of the internal liquid reaches the set value.

[0026] The structure of the cold-keeping container 1 is as follows: a cold-keeping interlayer is provided on the side wall of the cold-keeping container 1, and the cold-keeping interlayer is filled with liquid nitrogen. When in use, the temperature of the cold-keeping container 1 is adjusted by changing the amount of the filled liquid nitrogen.

[0027] The following description will not distinguish between the heat-insulating container 2 and the cold-insulating container 1, and will simply refer to the containers collectively.

[0028] Among them, the structure of the piston cylinder 13 is as follows: the piston cylinder 13 is provided with an oil inlet 15 and an oil outlet 16, and the piston cylinder 13 is provided with a reciprocating piston rod 14, the left limit of the piston rod 14 is located on the inner side of the oil inlet 15, and the right limit of the piston rod 14 is located on the outer side of the oil outlet 16. The container outlet is connected to the oil inlet 15 of the piston cylinder 13, and the oil outlet 16 of the piston cylinder 13 is connected to the measuring pipeline 11, and the measuring pipeline 11 is coated with a heat-insulating material. To ensure implementation, the outlet of the container is connected to the oil inlet 15 of the piston cylinder 13 through the oil pump 4, so that when the piston rod 14 is located at the left limit of the piston cylinder 13, the oil pump 4 can suck the liquid in the container into the piston cylinder 13, and enter the measuring pipeline 11 through the piston cylinder 13. In this embodiment, the pump selected is: a high-performance pressure-stabilizing pump. Because the measured liquids are all high-viscosity liquids, especially at low temperatures. The high-performance pressure-stabilizing pump adopts frequency conversion technology, which can be adjusted according to the viscosity of the measured liquid and provide a stable pressure source.

[0029] In addition, a throttle valve 3 is provided between the outlet of the container and the oil pump 4, through which the working process can be controlled.

[0030] Before measurement, liquid is first allowed to enter the piston cylinder 13 through the oil pump 4 and fill the piston cylinder 13 . The piston rod 14 can push the liquid in the piston cylinder 13 so that the liquid in the piston cylinder 13 comes out of the piston cylinder 13 .

[0031] A flow meter 10 to be tested, a viscosity sensor 8, a temperature sensor 6 and a pressure sensor 7 are installed on the measuring pipeline 11, wherein the flow meter 10 to be tested is a flow meter that needs to be calibrated, and it only needs to be installed on the measuring pipeline 11 through a bayonet; and the viscosity sensor 8, the temperature sensor 6 and the pressure sensor 7 are all commercially available products, which are used to measure the viscosity, temperature and pressure of the liquid respectively.

[0032] The measuring module 12 comprises a temperature sensor 6 , a microcontroller and a piston rod drive assembly 9 .

[0033] The microcontroller includes a lower-level single-chip microcomputer U1 (model: STM32).

[0034] The number of the temperature sensors 6 is at least 8, wherein four temperature sensors 6 are respectively installed in the heat-insulating container 2 and the cold-insulating container 1, and the temperature sensors 6 are used to collect the temperature of the container.

[0035] The viscosity sensor 8 is used to collect the viscosity of the liquid, and the pressure sensor 7 is used to collect the pressure of the liquid. The signal output ends of the temperature sensor 6, the viscosity sensor 8, the temperature sensor 6 and the pressure sensor 7 are connected to the signal input end of the lower microcontroller.

[0036] The signal output terminal of the lower single-chip microcomputer outputs a signal to connect the piston rod drive assembly 9, and the piston rod drive assembly 9 drives the movement of the piston. Among them, the piston rod drive assembly 9 includes a motor 18, a lead screw 17 and a grating displacement sensor for collecting the displacement of the lead screw 17. The motor 18 drives the lead screw 17 to rotate. A nut is screwed on the lead screw 17, and the nut drives the piston to reciprocate. Among them, the grating displacement sensor is a commercially available product, and the grating displacement sensor transmits the collected displacement to the microcontroller. During implementation, the output end of the grating displacement sensor is connected to the signal input end (pin P2.0) of the lower single-chip microcomputer, so that the collected displacement is transmitted to the lower single-chip microcomputer. The lower single-chip microcomputer controls whether the motor stops rotating according to the displacement, so that the movement of the piston is the same as the set amount.

[0037] In order to realize the control of the motor by the lower microcontroller, the motor drive circuit is connected to the signal output end of the lower microcontroller, and the motor can be driven by the motor drive circuit. The implementation method of the lower microcontroller output signal to drive the motor is: the signal output end of the lower microcontroller is connected to the motor drive circuit (the motor drive chip U2 (model ULN2003A) is connected to the lower microcontroller (pins P4.1, P4.2, P4.3, P4.4), and the motor drive chip U2 drives the forward and reverse rotation of the motor.), the motor drive circuit drives the rotation of the motor, and then controls the movement of the nut on the lead screw, driving the movement of the piston rod. The motor drive circuit is a mature existing technology.

[0038] In order to achieve temperature regulation, the lower-level single-chip microcomputer outputs a signal to drive the operation of the electric heating wire and the flow valve. By controlling the operation of the heating wire, the heating amount of the heat preservation container 2 is controlled, and then the temperature of the heat preservation container 2 is controlled. By controlling the flow valve, the amount of nitrogen entering the cold preservation container 1 is controlled, and then the temperature of the cold preservation container 1 is controlled.

[0039] The lower microcontroller drives the electric heating wire to work by connecting a relay drive circuit to the signal output terminal of the lower microcontroller, and the relay drive circuit drives the on and off of the electric heating wire and the opening and closing of the solenoid valve. The relay drive circuit is a mature prior art and will not be described in detail in this embodiment.

[0040] The lower microcontroller drives the flow valve in the following way: connect the flow valve to the PWM output terminal (pin P5.0) of the lower microcontroller, thereby controlling the opening size of the flow valve by controlling the PWM signal, thereby controlling the amount of nitrogen entering the cold insulation interlayer. Controlling the flow valve by PWM signal can be achieved by using existing methods.

[0041] The lower MCU is connected to the upper MCU U1 through the serial port, and the upper MCU U1 is connected to a display unit, wherein the display unit includes a display screen U2 (model LCD1602), and the upper MCU U1 is directly connected to the display screen U2. Thus, the lower MCU transmits the temperature information, viscosity information, pressure information and flow information of the liquid to the upper MCU U1 through the serial port, and the upper MCU U1 displays it on the display screen.

[0042] In order to facilitate the subsequent cleaning of the pipeline, a steam purge assembly is provided on the measuring pipeline 11. The steam purge assembly includes a steam generator, which is used to generate steam. The steam can purge the residual liquid in the measuring pipeline 11, thereby ensuring the accuracy of the next measurement result. The outlet of the steam generator is connected to the measuring pipeline 11, and the steam of the steam generator enters the measuring pipeline 11 to clean the liquid therein, thereby achieving the purpose of pipeline cleaning.

[0043] Embodiment 2, this embodiment is different from embodiment 1 in that, Figure 5 and Figure 6 As shown, in order to improve the use effect, the outlet of the steam generator is connected to the inlet of the heat preservation interlayer 19 and the measuring pipeline 11 through two steam pipelines 20 respectively. The two steam pipelines 20 are provided with solenoid valves. By controlling the opening of the solenoid valves, whether the steam enters the heat preservation interlayer 19 is controlled.

[0044] The lower microcontroller outputs a signal to control the closing and opening of the solenoid valve. The lower microcontroller outputs a signal to control the solenoid valve, which is a mature existing technology and will not be described in detail here. When implemented, a relay drive circuit can be used for control.

[0045] After the steam from the steam generator enters the heat preservation interlayer 19, the heat preservation container 2 can be quickly heated to improve the calibration speed and efficiency. After the steam from the steam generator enters the measuring pipeline 11, the measuring pipeline 11 can be steam-cleaned.

[0046] How to use:

[0047] First, determine whether to use the heat preservation container 2 or the cold preservation container 1 according to the flow meter that needs to be calibrated, and then fill the liquid into the selected container.

[0048] Assuming that the heat preservation container 2 is selected, the liquid is loaded into the heat preservation container 2; if the temperature needs to be set higher, the steam generator is first used to open the electromagnetic valve between the steam generator and the heat preservation interlayer 19, and the steam enters the heat preservation interlayer 19 to achieve rapid preheating of the heat preservation container 2. Subsequently, the microcontroller is used to control the electric heating wire of the heat preservation container 2 so that the heat preservation container 2 is maintained within the set temperature range. The oil pump 4 draws the liquid in the oil tank into the piston cylinder 13. When the measuring pipeline 11 is also full of liquid, it means that the piston cylinder 13 is in a full cylinder state. According to the range of the calibrated flow meter, 1 / 4, 1 / 2, 2 / 3 and full range of the range are selected in turn to determine the movement of the piston rod 14. The microcontroller transmits the movement of the piston rod 14 to the motor 18. The motor 18 drives the lead screw 17 to rotate the set distance so that the piston rod 14 moves. At the same time, the grating displacement sensor collects the actual displacement of the piston rod 14 to accurately control the operation of the motor 18. The flow rate of the liquid flowing through is calculated according to the displacement of the piston rod to obtain the actual flow value. Among them, the method of obtaining the liquid flow rate according to the movement of the piston rod is:

[0049] By q v =πhD 2 / 4t, where q v is the volume flow rate; D is the inner diameter of the piston cylinder; t is the piston running time, and h is the piston running distance.

[0050] Then, the flow value of the flow meter is compared with the actual flow value, and the error and uncertainty of the flow meter 10 under test are calculated.

[0051] After the calibration is completed, the steam generator is turned on to allow steam to be blown onto the measuring pipeline 11 , thereby cleaning the measuring pipeline 11 .

[0052] The utility model provides a calibration device for a gear flowmeter with variable viscosity. According to the use environment of the gear flowmeter and the difference between high-temperature liquid and low-temperature liquid, two calibration lines are used for calibration, so as to improve the accuracy in the calibration process and realize accurate calibration of the gear flowmeter.

Claims

1. A calibration device for a variable viscosity gear flow meter, characterized in that: It includes a measuring module, a low-temperature calibration line and a high-temperature calibration line. Both the low-temperature calibration line and the high-temperature calibration line include a piston cylinder. The piston cylinder is provided with an oil inlet and an oil outlet. A reciprocating piston rod is provided in the piston cylinder. The left limit of the piston rod is located on the inner side of the oil inlet, and the right limit of the piston rod is located on the outer side of the oil outlet. The low-temperature calibration line also includes a cold-keeping container. The low-temperature calibration line also includes a heat-keeping container. The outlets of the cold-keeping container and the heat-keeping container are respectively connected to the oil inlet of the corresponding piston cylinder. The oil outlet of the piston cylinder is respectively connected to the corresponding measuring pipeline. The measuring pipeline is equipped with a flow meter to be tested, a viscosity sensor, a temperature sensor and a pressure sensor. The measuring module includes a microcontroller and a piston rod drive assembly. The signal output ends of the viscosity sensor, the temperature sensor and the pressure sensor are connected to the signal input end of the microcontroller. The signal output end of the microcontroller outputs the signal connected to the piston rod drive assembly. The piston rod drive assembly drives the movement of the piston rod.

2. The calibration device for a variable viscosity gear flowmeter according to claim 1, characterized in that: The cold-keeping container and the heat-keeping container are both connected to the oil inlets of the corresponding piston cylinders through oil pumps.

3. The calibration device for a variable viscosity gear flowmeter according to claim 2, characterized in that: The side wall of the cold-keeping container is provided with a cold-keeping interlayer, and the heat-keeping container is provided with a heat-keeping interlayer.

4. The calibration device for a variable viscosity gear flowmeter according to claim 3, characterized in that: The piston rod driving assembly includes a motor, a lead screw and a grating displacement sensor for collecting the movement of the piston rod. The signal output end of the grating displacement sensor is connected to the signal input end of the microcontroller. The motor drives the lead screw to rotate. A nut is threaded on the lead screw, and the nut drives the piston rod to reciprocate.

5. The calibration device for a variable viscosity gear flowmeter according to claim 4, characterized in that: The measuring pipeline is also provided with a steam purge component, which includes a steam generator.

6. The calibration device for a variable viscosity gear flowmeter according to claim 5, characterized in that: The outlet of the steam generator is connected to a measuring line.

7. The calibration device for a variable viscosity gear flowmeter according to claim 6, characterized in that: The steam generator outlet is connected to the heat preservation interlayer inlet and the measuring pipeline through two steam pipelines respectively. Solenoid valves are arranged on the two steam pipelines. The microcontroller outputs signals to control the closing and opening of the solenoid valves.

8. The calibration device for a variable viscosity gear flowmeter according to claim 6 or 7, characterized in that: The cold-keeping interlayer is filled with liquid nitrogen.

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