Device for measuring dielectric constants of liquid under different pressures

Abstract

The utility model discloses a device for measuring dielectric constants of liquid under different pressures. The device comprises a pressure chamber, a measuring device, a sample container, liquid to be measured, a pressure regulating device, a vacuum pump and a temperature control device. The measuring device comprises a signal generator, a resistor, a variable rotary capacitor and an alternating current voltmeter, the pressure regulating device comprises a gas cylinder, a stop valve, a pressure buffer tank, a pressure regulating valve and a pressure sensor, the temperature control device is a circulating water bath, and the variable rotary capacitor and the sample container are fixed and placed in a pressure chamber. According to the device, the temperature and pressure in the pressure chamber are adjusted through the pressure adjusting device, the vacuum pump and the temperature control device, and voltages at two ends of the signal generator and the variable rotary capacitor under vacuum and different pressures are measured through the measuring device, so that the dielectric constant of liquid to be measured is indirectly calculated. The device is simple to operate, reliable in measurement precision and higher in measurement efficiency.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquid dielectric constant measurement technical field, specifically to a kind of device for measuring liquid dielectric constant under different pressure. BACKGROUND

[0002] Dielectric constant is the macro parameter of the electric characteristic of medium material, and is one of the constitutive parameters in Maxwell equation. The measurement technology of dielectric constant is mainly applied to solid material before. With the development of science and technology, the application value of liquid dielectric constant in biomedical, health care, food, beverage, chemical industry and pharmaceutical quality control fields is gradually explored, for example, through the measurement of liquid dielectric constant, the fluid state analysis and oil reservoir evaluation of deep underground reservoir, the control of the progress of polymerization, high-pressure dissolution and other reactions and the improvement of yield, and the detection of pollutant concentration of underground water and soil. The commonly used measurement methods include resonant cavity method, free space method, transmission line method and capacitance method. The first three methods reflect the dielectric constant of material by measuring the change of frequency response of sensitive element, and the fourth method calculates the dielectric constant of material by measuring the capacitance of capacitor.

[0003] As one of its characteristic parameters, the dielectric constant of liquid has many influencing factors, including composition, physical properties of constituent molecules, microstructure of material, temperature and pressure. The existing measurement device generally measures the dielectric constant of liquid with different components based on normal temperature or specific temperature, and ignores the influence of pressure. However, the increase of pressure will enhance the interaction between liquid molecules, change the electron cloud distribution of liquid, and further affect the change of liquid dielectric constant. When liquid is under different environmental pressure, the dielectric constant measured by the existing device is inaccurate, which has great influence on the analysis and evaluation of deep underground reservoir, high-pressure reaction and environment. Therefore, it is necessary to develop a device for measuring liquid dielectric constant under different pressure. UTILITY MODEL CONTENT

[0004] To solve the problems of the prior art, the utility model provides a device for measuring liquid dielectric constant under different pressure, which is simple to operate, reliable in measurement accuracy and higher in measurement efficiency.

[0005] The utility model realizes the technical scheme as follows: a device for measuring liquid dielectric constant under different pressure, comprising a pressure chamber, a measuring device, a sample container, a liquid to be measured, a pressure regulating device, a vacuum pump and a temperature control device.

[0006] The pressure chamber is connected with the pressure regulating device through a gas supply pipeline;

[0007] The pressure chamber is connected with the temperature control device through a circulation pipeline;

[0008] The sample container is fixed in the pressure chamber, and the liquid to be tested is placed into the sample container;

[0009] Specifically:

[0010] The pressure chamber includes a pressure chamber cylinder and a pressure chamber base; the pressure chamber cylinder is provided with an exhaust port, a water inlet, a water outlet, and a cable inlet, wherein the exhaust port is connected to a vacuum pump through a gas supply pipeline; the pressure chamber base is provided with an air inlet, and the sample container is fixed to the top surface of the base by threads.

[0011] The measuring device includes a signal generator, a resistor, a variable rotating capacitor, an AC voltmeter, and wires; the signal generator and the resistor are connected outside the pressure chamber via wires; there are two AC voltmeters, which are connected in parallel with the signal generator and the variable rotating capacitor outside the pressure chamber via wires; the variable rotating capacitor is placed inside the sample container, and the capacitor plate is fastened to the sample container opening by a snap fastener, and is connected in series with the signal generator and the resistor via wires with protective sleeves.

[0012] The pressure regulating device includes a gas cylinder, a shut-off valve, a pressure buffer tank, a pressure regulating valve, a pressure sensor, and a gas delivery pipeline; there are two shut-off valves, and their two ends are connected to the gas cylinder, the pressure buffer tank, and the pressure regulating valve through the gas delivery pipeline; the pressure sensor is connected to the gas inlet and the pressure regulating valve through the gas delivery pipeline.

[0013] The temperature control device includes a circulating water bath, an external circulation pipeline, and an internal circulation pipeline; the circulating water bath is connected to the inlet and outlet through the external circulation pipeline; the internal circulation pipeline is placed in the pressure chamber and fixed to the inlet and outlet with bolts.

[0014] Optionally, the signal generator can adjust the voltage and frequency to measure capacitance under different electric field strengths.

[0015] Optionally, the circulating water bath is a low-temperature cold bath, and the coolant can be a 50% diluted ethylene glycol solution.

[0016] Optionally, the protective sleeve can be made of stainless steel corrugated pipe to reduce the impact of pressure and temperature on the circuit, thereby making the measured values ​​more accurate.

[0017] Optionally, the gas cylinder may be a nitrogen cylinder to reduce the influence of the gas on the measurement of the dielectric constant of the liquid.

[0018] The beneficial effects of this utility model are:

[0019] The liquid dielectric constant device provided by this utility model controls the temperature and pressure of the environment in which the liquid is located by setting up a temperature control device, a pressure regulating device, and a vacuum pump. It detects the voltage of the circuit by setting up a measuring device, and then calculates the capacitance after adding the liquid to be tested according to the voltage gain calculation formula, thereby indirectly calculating the dielectric constant of the liquid to be tested. In this way, not only can the dielectric constant of liquids under different temperatures and pressures be measured more accurately, but the device is also simple to operate and has higher measurement efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of a device for measuring the dielectric constant of liquids under different pressures according to the present invention;

[0021] Figure 2 This is a schematic diagram of the temperature control device and its pipeline connections according to this utility model;

[0022] Figure 3 This is a front view of the sample container and pressure chamber base fixing of this utility model;

[0023] Figure 4 This is a simplified circuit diagram of the measuring device of this utility model.

[0024] Icons: 1-Pressure chamber; 1-1-Pressure chamber cylinder; 1-2-Pressure chamber base; 1-3-Exhaust port; 1-4-Water inlet; 1-5-Water outlet; 1-6-Wire inlet; 1-7-Air inlet; 1-8-Threaded interface; 2-Measuring device; 2-1-Signal generator; 2-2-Resistor; 2-3-Variable rotary capacitor; 2-4-AC voltmeter; 2-5-Wire; 3-Sample container; 4-Liquid to be tested; 5-Pressure regulating device; 5-1-Gas cylinder; 5-2-Stop valve; 5-3-Pressure buffer tank; 5-4-Pressure regulating valve; 5-5-Pressure sensor; 5-6-Gas pipeline; 6-Vacuum pump; 7-Temperature control device; 7-1-Circulating water bath; 7-2-External circulation pipeline; 7-3-Internal circulation pipeline. Detailed Implementation

[0025] The technical solutions of the present invention will now be described with reference to the accompanying drawings of the embodiments thereof.

[0026] To provide a clear and complete description, it is obvious that the described embodiments are only a part of the embodiments of this utility model, and not all of them. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] like Figure 1 , Figure 2As shown, an apparatus for measuring the dielectric constant of a liquid under different pressures is characterized by comprising a pressure chamber (1), a measuring device (2), a sample container (3), a liquid to be tested (4), a pressure regulating device (5), a vacuum pump (6), and a temperature control device (7).

[0028] The pressure chamber (1) includes a pressure chamber cylinder (1-1) and a pressure chamber base (1-2); preferably, the pressure chamber adopts a detachable integrated structure, reducing the time for sample changing; the pressure chamber cylinder (1-1) has an exhaust port (1-3), a water outlet (1-4), a water inlet (1-5), and a cable inlet (1-6), wherein the exhaust port (1-3) is connected to the vacuum pump (6) through a gas pipeline (5-6); the pressure chamber base (1-6) has an air inlet (1-7). Figure 3 As shown, the pressure chamber (1) is threadedly connected to the sample container (3) through four threaded interfaces (1-8) on the top surface of the pressure chamber base (1-2).

[0029] The measuring device (2) includes a signal generator (2-1), a resistor (2-2), a variable rotating capacitor (2-3), an AC voltmeter (2-4), and a wire (2-5). There are two AC voltmeters (2-4), which are connected in parallel with the signal generator (2-1) and the variable rotating capacitor (2-3) outside the pressure chamber (1) via the wire (2-5) to calibrate the circuit and measure the voltage across the signal generator (2-1) and the variable rotating capacitor (2-3). The variable rotating capacitor (2-3) is placed inside the sample container (3), and the capacitor plate is fastened to the container opening by a snap fastener. It is connected in series with the signal generator (2-1) and the resistor (2-2) outside the pressure chamber (1) via the wire (2-5). Preferably, the part of the wire (2-5) from the inlet (1-6) to the variable rotating capacitor (2-3) should be equipped with a heat-insulating sleeve to reduce the influence of pressure and temperature on the circuit.

[0030] The pressure regulating device (5) includes a gas cylinder (5-1), a shut-off valve (5-2), a pressure buffer tank (5-3), a pressure regulating valve (5-4), a pressure sensor (5-5), and a gas transmission pipeline (5-6). Gas is output from the gas cylinder (5-1), the shut-off valve (5-2) near the gas cylinder (5-1) is opened, and after being balanced by the pressure buffer tank (5-3), the other shut-off valve (5-2) is opened. Then, the pressure regulating valve (5-4) is adjusted so that the gas enters the pressure chamber (1), and the pressure in the pressure chamber (1) is detected in real time by the pressure sensor (5-5).

[0031] like Figure 2As shown, the temperature control device (7) includes a circulating water bath (7-1), an external circulation pipeline (7-2), and an internal circulation pipeline (7-3). The circulating water bath (7-1) is connected to the inlet (1-4) and the outlet (1-5) through the external circulation pipeline (7-2). The internal circulation pipeline (7-2) is spirally arranged in the pressure chamber (1) and fixed to the inlet (1-4) and the outlet (1-5) by bolts, thereby forming a closed loop with the circulating water bath (7-1) and the external circulation pipeline (7-2), and controlling and displaying the temperature in the pressure chamber (1) through the circulating water bath (7-1).

[0032] In a specific embodiment of the technical solution, the application of this utility model to measure the dielectric constant of a liquid under pressure includes the following steps:

[0033] S1. Without adding the liquid to be tested to the sample container, place the variable rotating capacitor inside the sample container and secure the capacitor plate to the sample container with a snap fastener.

[0034] S2. Fix the sample container to the pressure chamber base with bolts, and then lead the wire with the protective sleeve out from the inlet on the pressure chamber cylinder and connect it in series with the signal generator and resistor.

[0035] S3. Assemble the pressure chamber base and the pressure chamber cylinder.

[0036] S4. After plugging the air inlet with a nut, use a vacuum pump to evacuate the pressure chamber to a vacuum.

[0037] S5. Adjust the temperature control device according to the experimental requirements so that the temperature in the pressure chamber reaches the preset value.

[0038] S6. Adjust the signal generator to output a certain voltage amplitude and frequency, and measure the voltages across the signal generator and the variable rotating capacitor using an AC voltmeter. , The frequency of the output circuit at this time is denoted as f0.

[0039] S7. According to the formula , The capacitance of a variable rotating capacitor in a vacuum can be calculated.

[0040] In the formula G v R is the voltage gain, C is the resistance value, and ω is the angular frequency.

[0041] S8. After disassembling the pressure chamber and adding the liquid to be tested into the sample container, place the variable rotating capacitor inside the sample container, ensuring that its electrodes are completely immersed in the liquid to be tested, and then fix the capacitor plate to the sample container.

[0042] S9. Repeat steps S2-S3.

[0043] S10. Plug the air outlet with a nut, open the air inlet and connect it to the pressure regulating device.

[0044] S11. Open the shut-off valve and control the pressure in the pressure chamber through the pressure regulating valve so that the reading on the pressure sensor reaches the preset value of the experiment.

[0045] S10. Repeat steps S5-S7, keeping the temperature, voltage amplitude, and frequency constant throughout the process, to obtain the capacitance of the variable rotating capacitor under the preset pressure. .

[0046] S11. To eliminate the influence of the shape of the variable rotating capacitor, change the geometric configuration of the variable rotating capacitor and repeat steps S1-S10. During the process, the temperature, pressure, voltage amplitude, and frequency remain constant. The capacitances of the variable rotating capacitor in vacuum and the test liquid under the other geometric configuration can be calculated as follows: and .

[0047] S13, According to the formula The dielectric constant of the liquid under test at the preset pressure can be calculated.

[0048] It is important to note that when measuring the voltage across the signal generator and the variable rotating capacitor, each measurement should be repeated at least five times, and the average value should be taken, ensuring that the deviation from the measured value does not exceed 0.05%. The dielectric constant of the liquid under test should be calculated using the average value.

[0049] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for measuring the dielectric constant of a liquid at different pressures, characterized by: The device comprises a pressure chamber (1), a measuring device (2), a sample container (3), a liquid to be measured (4), a pressure regulating device (5), a vacuum pump (6), a temperature control device (7); The pressure chamber (1) comprises a pressure chamber cylinder (1-1) and a pressure chamber base (1-2); The pressure chamber (1) is connected with the pressure regulating device (5) through a gas pipeline; The pressure chamber (1) is connected with the temperature control device (7) through a circulating pipeline; The sample container (3) is fixed in the pressure chamber (1), and the liquid to be measured (4) is put into the sample container (3).

2. The device for measuring the dielectric constant of a liquid under different pressures according to claim 1, characterized in that: The pressure chamber cylinder (1-1) is provided with an exhaust port (1-3), a water inlet (1-4), a water outlet (1-5) and a wire inlet (1-6), and the pressure chamber base (1-2) is provided with an air inlet (1-7); The exhaust port (1-3) is connected with the vacuum pump (6) through a gas pipeline; the top surface of the pressure chamber base (1-2) is threadedly connected with the sample container (3).

3. A device for measuring the dielectric constant of a liquid under different pressures according to claim 2, characterized in that: The measuring device (2) comprises a signal generator (2-1), a resistor (2-2), a variable rotary capacitor (2-3), an AC voltmeter (2-4) and a wire (2-5); The signal generator (2-1) and the resistor (2-2) are connected with the pressure chamber (1) through the wire (2-5); the AC voltmeter (2-4) has two, which are respectively connected with the signal generator (2-1) and the variable rotary capacitor (2-3) through the wire (2-5) in parallel; the variable rotary capacitor (2-3) is embedded in the sample container (3) through a buckle, and is connected with the signal generator (2-1) and the resistor (2-2) in series through the wire (2-5).

4. The apparatus of claim 3, wherein: The pressure regulating device (5) comprises a gas cylinder (5-1), a stop valve (5-2), a pressure buffer tank (5-3), a pressure regulating valve (5-4), a pressure sensor (5-5) and a gas pipeline (5-6); The stop valve (5-2) has two ends connected with the gas cylinder (5-1), the pressure buffer tank (5-3) and the pressure regulating valve (5-4) through the gas pipeline (5-6); the pressure sensor (5-5) is connected with the air inlet (1-7) and the pressure regulating valve (5-4) through the gas pipeline (5-6).

5. A device for measuring the dielectric constant of a liquid under different pressures according to claim 4, characterized in that: The temperature control device (7) comprises a circulating water bath (7-1), an outer circulating pipeline (7-2) and an inner circulating pipeline (7-3); The circulating water bath (7-1) is connected with the water inlet (1-4) and the water outlet (1-5) through the outer circulating pipeline (7-2); the inner circulating pipeline (7-3) is fixed in the pressure chamber (1) through bolts and the water inlet (1-4) and the water outlet (1-5).

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