CN204881769U - Low temperature liquid nitrogen liquid level detection device - Google Patents

Abstract

The utility model discloses a low-temperature liquid nitrogen liquid level detection device, comprising: a cylindrical tank, a capacitance sensor, a shielded cable and a capacitance processing circuit; the capacitance sensor is cylindrical, and the capacitance sensor is vertically arranged in the cylindrical tank; The capacitance processing circuit is connected to the shielded cable; the shielded cable is connected to the upper end of the capacitance sensor, and a round hole is opened at the lower end of the capacitance sensor. Through the above method, the utility model can detect the size of the capacitance in the capacitor, and calculate the information of the low-temperature liquid nitrogen level according to the size of the capacitance; the low-temperature liquid nitrogen level detection device is simple in structure, easy to use, low in cost, and small in size. The liquid level of cryogenic liquid can be detected.

Description

A low-temperature liquid nitrogen liquid level detection device

technical field

The utility model relates to the field of liquid level detection devices, in particular to a low-temperature liquid nitrogen liquid level detection device.

Background technique

In industrial applications or experimental tests, it is often necessary to detect the liquid level. The commonly used liquid level detection method is to use the flap box outside the main body of the liquid nitrogen level gauge to accept the action of the float inside the body to make the flap flip and display red and white, and then The movement of the float indicates different liquid heights; there is a striking scale scale on the left side of the indicator, and the liquid level height of the liquid can be obtained according to the displayed red and white scale scales. Another method is to set at least two pressure sensors in the liquid contained in the liquid measuring cylinder, and calculate the liquid pressure difference and the gas pressure difference according to the values measured by the sensors; then according to the calculated liquid pressure difference, gas pressure difference and The vertical distance between the sensors calculates the height value of the liquid level. However, none of these methods can accurately measure the liquid level of cryogenic liquid nitrogen (-196°C), and it is more difficult to apply in a limited installation space.

Utility model content

The technical problem mainly solved by the utility model is to provide a low-temperature liquid nitrogen liquid level detection device, which can detect the capacitance in the capacitor, and calculate the information of the low-temperature liquid nitrogen liquid level according to the capacitance; The device has the advantages of simple structure, convenient use, low cost and small volume, and can detect the liquid level of cryogenic liquid.

In order to solve the above technical problems, a technical solution adopted by the utility model is to provide a low-temperature liquid nitrogen liquid level detection device, including: a cylindrical tank, a capacitance sensor, a shielded cable and a capacitance processing circuit; the capacitance sensor is cylindrical, The capacitive sensor is vertically arranged in the cylindrical tank; the capacitive processing circuit is connected to the shielded cable; the shielded cable is connected to the upper end of the capacitive sensor, and a round hole is opened at the lower end of the capacitive sensor.

Preferably, the capacitive sensor includes an internal electrode of the capacitive sensor and an external electrode of the capacitive sensor; the external electrode of the capacitive sensor is a stainless steel cylindrical hollow structure; the internal electrode of the capacitive sensor is a solid stainless steel rod.

Preferably, the height of the capacitive sensor is much larger than the diameter of the capacitive sensor.

The beneficial effects of the utility model are: the utility model can detect the capacitance in the capacitor, and calculate the information of the low-temperature liquid nitrogen level according to the capacitance.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of a preferred embodiment of a low-temperature liquid nitrogen liquid level detection device of the present invention;

The markings of the components in the drawings are as follows: 1. Inner electrode of the capacitance sensor; 2. Outer electrode of the capacitance sensor; 3. Round hole; 4. Lead wire; 5. Cylindrical tank; 6. Capacitance processing circuit.

Detailed ways

The preferred embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings, so that the advantages and characteristics of the utility model can be more easily understood by those skilled in the art, so that the protection scope of the utility model can be defined more clearly .

Please refer to Fig. 1, the utility model embodiment comprises:

A low-temperature liquid nitrogen liquid level detection device, comprising: a cylindrical tank 5, a capacitance sensor, a shielded cable 4 and a capacitance processing circuit 6; the capacitance sensor is cylindrical, which can prevent the capacitance from being affected by the outside world. The capacitive sensor is vertically arranged in the cylindrical tank 5, and the cylindrical tank 5 is filled with liquid nitrogen. The capacitance processing circuit 6 is connected to the shielded cable 4, and the shielded cable 4 is connected to the upper end of the capacitance sensor, which can complete the linearization process for the nonlinear problem of the capacitance and the liquid level that occurs during the detection process. The detection information provides a convenient interface. The lower end of the capacitive sensor is provided with a circular hole 3, which can keep the liquid nitrogen level inside the capacitive sensor at the same height as the external one, which is convenient for accurate calculation of the liquid nitrogen level. The capacitive sensor includes a capacitive sensor internal electrode 1 and a capacitive sensor external electrode 2; the capacitive sensor external electrode 2 is a stainless steel cylindrical hollow structure, and the stainless steel cylindrical hollow structure solves the shielding problem of the electromagnetic field and avoids the measured capacitance being affected by the outside world. impact, and low temperature resistance, easy to use in low temperature liquid; the electrode 1 of the capacitance sensor is a solid stainless steel rod, the solid stainless steel rod has good low temperature resistance, and can be used in low temperature liquid. The height of the capacitive sensor is much larger than the diameter of the capacitive sensor, which can facilitate the installation of the capacitive sensor in a limited space.

A low-temperature liquid nitrogen liquid level detection method: the capacitance sensor is vertically placed in a cylindrical tank filled with liquid nitrogen, and the liquid nitrogen flows into the capacitance sensor from the round hole at the lower end of the capacitance sensor until it flows into the liquid nitrogen and the cylinder in the capacitance sensor The liquid nitrogen in the tank is level; the capacitance processing circuit handles the nonlinear problem of capacitance and liquid level; the height of the liquid nitrogen in the cylindrical tank can be obtained by calculating the height of the liquid nitrogen inside the capacitance sensor; the cylinder can be calculated by the following formula Liquid nitrogen level in the tank:

In the formula, R is the diameter of the outer electrode of the capacitive sensor; r is the diameter of the inner electrode of the capacitive sensor; is the vacuum dielectric constant; is the dielectric constant of the measured liquid; L is the height of the capacitive sensor; h is the height of liquid nitrogen inside the capacitive sensor.

The utility model can detect the size of the capacitance in the capacitor, and calculate the information of the low-temperature liquid nitrogen level according to the size of the capacitance; the low-temperature liquid nitrogen level detection device has simple structure, convenient use, low cost and small volume, and can detect low-temperature liquid the liquid level.

The above is only an embodiment of the utility model, and does not limit the patent scope of the utility model. Any equivalent structure or equivalent process conversion made by using the utility model specification and accompanying drawings, or directly or indirectly used in other Related technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims (3)

1. a low temperature liquid nitrogen liquid level detection device, is characterized in that, comprising: cylindrical tank, capacitive transducer, shielded cable and electric capacity treatment circuit; Described capacitive transducer is cylindrical, and capacitive transducer is vertically set in described cylindrical tank; Described electric capacity treatment circuit is connected with described shielded cable; Described shielded cable is connected to the upper end of described capacitive transducer, and the lower end of capacitive transducer has circular hole.

2. a kind of low temperature liquid nitrogen liquid level detection device according to claim 1, is characterized in that: described capacitive transducer comprises electrode and capacitive transducer external electrode in capacitive transducer; Described capacitive transducer dispatch from foreign news agency very stainless steel cylindrical hollow configuration; In described capacitive transducer, electrode is solid stainless steel bar.

3. a kind of low temperature liquid nitrogen liquid level detection device according to claim 1, is characterized in that: the height of described capacitive transducer is much larger than the diameter of capacitive transducer.