A vibrating wire density meter

Abstract

The utility model relates to sensing technical field, concretely relates to a vibrating wire density meter, including liquid storage cavity, the upper end fixed of liquid storage cavity is equipped with the shell, the inside of shell is equipped with movable baffle, the inside of shell still is equipped with steel string, both ends of steel string all are fixed through clamping string device, the inside one side of shell still is equipped with coil, the middle of shell still is equipped with spring, one end of spring is fixedly connected with movable baffle, and penetrates the upper end of liquid storage cavity and is connected with the upper end sliding of liquid storage cavity, the inside of liquid storage cavity is equipped with the float ball, the other end of spring is fixedly connected with float ball, the utility model utilizes a series of advantages of vibrating string principle, such as vibrating wire sensor's frequency signal can long distance transmission, sensor's temperature drift and zero drift are small, can solve the problem of low precision, poor reliability and the like of the current on -line monitoring class density meter.

Description

Technical Field

[0001] This utility model relates to the field of sensing technology, specifically to a vibrating wire density meter. Background Technology

[0002] A liquid density meter is a specialized instrument used to measure the density of liquids, with applications spanning a wide range of fields, including industrial production, public welfare, and scientific research. In the industrial sector, the petroleum industry uses it to detect the density of crude oil, gasoline, diesel, and other petroleum products, linking this to their calorific value and storage and transportation safety. In battery production, it measures the electrolyte density to determine the battery's state of charge. In the public welfare and food industries, brewing and dairy products use density meters to detect key indicators such as alcohol content and milk concentration to ensure product compliance; in beverage production, it monitors the density of syrups and juices to maintain consistent flavor. In environmental protection and scientific research, it measures the density of wastewater and sewage to analyze pollutant content and assess treatment effectiveness. Furthermore, liquid density meters play an irreplaceable role in ship ballast water commissioning (using density to determine buoyancy balance) and in pharmaceutical industry drug concentration calibration.

[0003] Currently, products for measuring liquid density are based on various principles, but they all have certain drawbacks: they are not suitable for long-distance transmission, and the density meters have low accuracy and poor reliability. Summary of the Invention

[0004] In response to the problems raised in the background art, this utility model provides a vibrating wire density meter to solve them, and the following will further elaborate on this utility model.

[0005] A vibrating wire densitometer includes a liquid storage cavity, an outer shell fixedly provided at the upper end of the liquid storage cavity, a movable baffle provided inside the outer shell, the movable baffle being slidably connected to the inside of the outer shell, and a steel wire also provided inside the outer shell, both ends of the steel wire being fixed by a wire clamping device, wherein the upper wire clamping device is fixed to the upper end of the inner cavity of the outer shell, and the lower wire clamping device is fixed to the movable baffle. A coil is also provided on one side inside the outer casing, and a general-purpose vibrating wire acquisition instrument is connected to the coil. A spring is also provided in the middle of the outer casing. One end of the spring is fixedly connected to the movable baffle and passes through the upper end of the liquid storage cavity and is slidably connected to the upper end of the liquid storage cavity. A float is provided inside the liquid storage cavity, and the other end of the spring is fixedly connected to the float.

[0006] Preferably, an inlet is provided on one side of the liquid storage cavity, and an outlet is provided at the lower end of the liquid storage cavity.

[0007] Preferably, two baffles are also fixed on the inner side of the outer casing.

[0008] Preferably, the liquid storage chamber is also provided with a transparent viewing window.

[0009] Preferably, a temperature sensor is also provided inside the liquid storage cavity.

[0010] Preferably, the liquid storage chamber is made of 316L stainless steel.

[0011] Preferably, the float is made of TC4 titanium alloy, precision machined to a size of Ø25×30mm, and weighs 112.5g.

[0012] Beneficial effects: Compared with the existing technology, this utility model utilizes a series of advantages of the vibrating wire principle, such as the frequency signal of the vibrating wire sensor can be transmitted over long distances (generally exceeding 1000 meters); the temperature drift and zero drift of the sensor are small; no power supply is required (excitation is required, but the excitation and signal are on the same set of signal lines); at the same time, because the vibrating wire sensing element can be well sealed, it has excellent corrosion resistance and is suitable for long-term monitoring under harsh conditions, which can solve the problems of low accuracy and poor reliability of current online monitoring density meters. Attached Figure Description

[0013] Figure 1 : Schematic diagram of the structure of this utility model.

[0014] In the diagram: 1. Liquid storage chamber; 2. Float; 3. Spring; 4. Movable baffle; 5. Baffle; 6. Steel string; 7. Coil; 8. String clamping device; 9. Outer shell; 10. Liquid inlet; 11. Temperature sensor; 12. Liquid outlet. Detailed Implementation

[0015] The following detailed description of a specific embodiment of the present invention is based on the accompanying drawings.

[0016] A vibrating wire densitometer includes a liquid storage chamber 1 for storing the liquid to be measured. An inlet 10 is provided on one side of the liquid storage chamber 1, and an outlet 12 is provided at the lower end of the liquid storage chamber 1.

[0017] A housing 9 is fixedly provided at the upper end of the liquid storage cavity 1. A movable baffle 4 is provided inside the housing 9. The movable baffle 4 is slidably connected to the inside of the housing 9. A steel wire 6 is also provided inside the housing 9. Both ends of the steel wire 6 are fixed by a wire clamping device 8. The upper wire clamping device 8 is fixed to the upper end of the inner cavity of the housing, and the lower wire clamping device 8 is fixed to the movable baffle 4. It should be noted that the wire clamping device 8 is existing technology and is designed to clamp the steel wire. It will not be elaborated on here.

[0018] A coil 7 is also provided inside the outer casing 9 on one side. The coil 7 is mainly used to excite the steel string, causing it to vibrate, and simultaneously picking up the vibration frequency of the steel string. Generally, to improve the excitation effect, electrical pure iron is inserted into the center of the coil. The coil maintains a certain distance from the steel string; this distance needs to be small enough to ensure effective signal excitation and pickup, while also preventing the steel string from touching the coil during vibration, thus affecting signal pickup. A general-purpose vibrating string acquisition instrument is also connected externally to the coil 7; this instrument is used to display the vibration frequency of the steel string.

[0019] A spring 3 is also provided in the middle of the outer shell 9. One end of the spring 3 is fixedly connected to the movable baffle 4, and passes through the upper end of the liquid storage cavity 1 and is slidably connected to the upper end of the liquid storage cavity 1. A float 2 is provided inside the liquid storage cavity 1, and the other end of the spring 3 is fixedly connected to the float 2.

[0020] Two baffles 5 are also fixed inside the outer casing 9, and the baffles 5 are positioned above the movable baffle 4.

[0021] When in use, the liquid to be tested is poured into the storage chamber 1 through the inlet 10. The storage chamber 1 is also equipped with a transparent viewing window for observing the liquid level. The liquid level should submerge the float 2. At this time, the float is subjected to its own weight and the buoyancy of the liquid being tested, and the resultant force is transmitted to the tension of the steel string 6 through the spring 3. The tension of the steel string 6 has a functional relationship with the density of the liquid being tested, so the density of the liquid can be obtained by measuring the tension of the steel string. The tension of the steel string can also be obtained by measuring the vibration frequency of the steel string through a coil. It should be noted that a temperature sensor 11 is also installed inside the storage chamber 1. The function of the temperature sensor 11 is to measure the temperature of the liquid being tested and perform temperature compensation when necessary. After the measurement is completed, the drain port is opened to drain the liquid being tested. After the measurement is completed, the storage chamber and the float need to be cleaned with a special cleaning solution.

[0022] Force analysis: Forces acting on the buoy: Gravity Fg = mg, Buoyancy Fb = ρlVg (m: mass of the buoy; ρl: density of the buoy; V: volume of the buoy; g: acceleration due to gravity) Steel string tension: T Equilibrium equation: T + Fb = mg, i.e., T = mg - ρlVg The relationship between the tension of a steel string and its frequency is: T = 4μL²f² (μ: linear density of the steel string; L: gauge length of the steel string; f: the current first natural frequency of the steel string). get:

[0023] Where: ρf=m / V is the density of the buoy; It is the sensitivity coefficient of the sensor.

[0024] The final result is:

[0025] It can be seen that the density of the liquid being measured has a quadratic function relationship with the current natural frequency of the steel string. Since the density ρl of the float and the sensitivity coefficient K of the sensor can be obtained through calibration, the density of the liquid being measured can be obtained as long as the current frequency of the steel string can be measured.

[0026] Calibration of the sensor's sensitivity coefficient K: In practice, a two-point calibration method can be used, that is, selecting two liquids with known densities, ρ1 and ρ2, respectively. This allows us to obtain the corresponding frequencies f1 and f2, which can then be obtained using the formula... The sensitivity coefficient K can be obtained as:

[0027] Liquid storage chamber: Select the appropriate material according to the type of liquid being tested, mainly considering resistance to media corrosion (acid / alkali / organic solvent), 316L stainless steel or titanium alloy can be used.

[0028] Float: Made of TC4 titanium alloy, precision machined to dimensions Ø25×30 mm, with a weight of 112.5 g.

[0029] Spring: A high-stiffness spring with k=5200 N / m and a pre-compression of δ0=1.2 mm (corresponding to an initial tension of 6.24 N in the steel string) is used.

[0030] Steel string and string clamping device: The steel string for the sensing element can be made of carbon tool steel, high-strength steel wire, or guitar string, etc. The diameter is 0.2~0.5mm, and the length-to-diameter ratio is generally not less than 200. The string clamping devices at both ends of the steel string can be fixed by mechanical clamping, or a welding process can be added to the clamping process to improve the long-term stability of the sensor.

[0031] Temperature sensor: A thermistor temperature sensor can be used and placed inside a thermally conductive metal protective cover.

[0032] Housing: The sensor housing can be made of stainless steel, which can prevent corrosion and shield against external electromagnetic interference.

[0033] Compared with existing technologies, this utility model utilizes a series of advantages of the vibrating wire principle, such as the ability of the frequency signal of the vibrating wire sensor to be transmitted over long distances (generally exceeding 1000 meters); low temperature drift and zero drift of the sensor; no power supply required (excitation is required, but the excitation and signal are on the same set of signal lines); and because the vibrating wire sensing element can be well sealed, it has excellent corrosion resistance and is suitable for long-term monitoring under harsh conditions, thus solving the problems of low accuracy and poor reliability of current online monitoring density meters.

[0034] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A vibrating wire densitometer, characterized in that: The device includes a liquid storage cavity (1), an outer shell (9) is fixedly provided at the upper end of the liquid storage cavity (1), a movable baffle (4) is provided inside the outer shell (9), the movable baffle (4) is slidably connected to the inside of the outer shell (9), and a steel wire (6) is also provided inside the outer shell (9). Both ends of the steel wire (6) are fixed by a wire clamping device (8), wherein the upper wire clamping device (8) is fixed to the upper end of the inner cavity of the outer shell, and the lower wire clamping device (8) is fixed to the movable baffle (4). A coil (7) is provided on one side inside the outer shell (9). A universal vibrating wire acquisition instrument is also connected to the coil (7). A spring (3) is provided in the middle of the outer shell (9). One end of the spring (3) is fixedly connected to the movable baffle (4) and passes through the upper end of the liquid storage cavity (1) and is slidably connected to the upper end of the liquid storage cavity (1). A float (2) is provided inside the liquid storage cavity (1). The other end of the spring (3) is fixedly connected to the float (2).

2. The vibrating wire density meter according to claim 1, characterized in that: An inlet (10) is provided on one side of the liquid storage cavity (1), and an outlet (12) is provided at the lower end of the liquid storage cavity (1).

3. The vibrating wire density meter according to claim 1, characterized in that: Two baffles (5) are also fixed inside the outer casing (9).

4. A vibrating wire density meter according to claim 1, characterized in that: The liquid storage chamber (1) is also provided with a transparent window.

5. A vibrating wire density meter according to claim 1, characterized in that: A temperature sensor (11) is also provided inside the liquid storage cavity (1).

6. A vibrating wire density meter according to claim 1, characterized in that: The liquid storage chamber (1) is made of 316L stainless steel.

7. A vibrating wire density meter according to claim 1, characterized in that: The float (2) is made of TC4 titanium alloy and is precision machined to a size of Ø25×30 mm with a mass of 112.5 g.

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