CN111947027A - Low-temperature liquefied gas level measuring method - Google Patents

Abstract

The invention belongs to the technical field of low-temperature liquefied gas, and particularly relates to a low-temperature liquefied gas liquid level measuring method which comprises the following steps: providing a mounting rod and a plurality of temperature sensors, and sequentially mounting the temperature sensors on the outer wall of the mounting rod from bottom to top; holding the upper end of the installation rod, installing the installation rod in the low-temperature liquefied gas in a way that the installation rod is vertical to the liquid level of the low-temperature liquefied gas, and standing for a period of time to keep the installation rod and the liquid level of the low-temperature liquefied gas relatively stable; each temperature sensor transmits the measured temperature value to a display processor, and the display processor calculates the temperature difference value of two adjacent temperature sensors; the temperature difference of the low-temperature liquefied gas in the gas state and the liquid state and the temperature change rule of the temperature in the gas phase space and the liquid phase space respectively are utilized to find out the numerical value of the temperature difference and the numerical value of the temperature change mutation, the liquid level height of the low-temperature liquefied gas is judged according to the height calibrated by the temperature sensor at the temperature change mutation position, and the measurement accuracy is high.

Description

Low temperature liquefied gas liquid level measurement method

technical field

The invention belongs to the technical field of low-temperature liquefied gas, and in particular relates to a method for measuring the liquid level of low-temperature liquefied gas.

Background technique

The low temperature liquid level sensor is used to measure the liquid level of low temperature liquids such as liquid nitrogen. It plays an important role in low temperature testing and is an indispensable instrument to ensure the normal progress of scientific research experiments and industrial production.

At present, there are many methods for measuring low temperature liquid level, including thermal oscillation method, superconducting wire method, resistance method, diode method and capacitance method, etc. In all the above-mentioned methods, the difference in electrical conductivity or thermal conductivity or resistance and capacitance characteristics inside and outside the cryogenic liquid is used to achieve the purpose of judging the height of the liquid level. The difference is limited, so no matter how the sensor itself is changed, it is difficult to make a greater breakthrough in the accuracy of liquid level measurement.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a low-temperature liquefied gas liquid level measurement method, which aims to solve the technical problem that the method for measuring the low-temperature liquid liquid level in the prior art has certain limitations and cannot further improve the liquid level measurement accuracy.

In order to achieve the above purpose, a method for measuring the liquid level of a low-temperature liquefied gas provided by an embodiment of the present invention includes the following steps:

S100: Provide a mounting rod and a plurality of temperature sensors, and install the plurality of temperature sensors on the mounting rod in sequence from bottom to top;

S200: Provide a display processor for processing and displaying the data transmitted from the plurality of temperature sensors;

S300: Hold the upper end of the installation rod, and install the installation rod in the low-temperature liquefied gas perpendicular to the liquid level of the low-temperature liquefied gas;

S400: stand for a period of time to keep the liquid level of the installation rod and the low-temperature liquefied gas relatively stable;

S500: Power on a plurality of the temperature sensors and the display processor, each of the temperature sensors transmits the measured temperature value to the display processor, and obtains a temperature difference between two adjacent temperature sensors Numerical value; using the temperature difference of low-temperature liquefied gas in gas and liquid states, and the law of temperature change in gas phase space and liquid phase space respectively, find out the value of temperature difference and the value of sudden change in temperature, according to the change of temperature The height calibrated by the temperature sensor determines the liquid level of the low-temperature liquefied gas.

Optionally, in the step S300, the installation rod is placed in the low-temperature liquefied gas along the direction perpendicular to the liquid level of the warm liquefied gas, and the lower end of the installation rod is extended straight to the bottle of the low-temperature adiabatic gas cylinder. end.

Optionally, in the step S300, the period of time is 5s˜20s.

Optionally, in the step S100, the mounting base of the temperature sensor is provided with a mounting plate, and the mounting plates of a plurality of the temperature sensors are screwed to the outer wall of the mounting rod in sequence from bottom to top, and two adjacent ones are installed. There is a longitudinal spacing and a radial spacing between the sensing ends of the temperature sensor.

Optionally, in the step S100, a plurality of adjustment assemblies are also provided, each adjustment assembly corresponds to the temperature sensor; the adjustment assembly includes a bolt and a nut; the installation rod is a hollow rod, and the The outer wall of the mounting rod is provided with a plurality of longitudinally distributed strip grooves, and each strip groove corresponds to one of the temperature sensors; the mounting plate is provided with mounting holes;

First, the screw of the bolt is movably connected to the strip groove, so that the nut of the bolt is limited by the strip groove in the installation rod, and then the installation hole is sleeved on the bolt Then, the nut is threadedly connected to the screw rod of the bolt, and finally the nut is tightened to fix the mounting plate on the bolt.

Optionally, in the step S100, the outer wall of the mounting rod is provided with a gap at the top or bottom of the strip groove, and the nut of the bolt is first passed through the gap, and then the bolt is inserted into the groove. The screw is movably connected to the strip groove.

Optionally, in the step S100, the longitudinal spacing is 0 mm˜10 mm.

Optionally, in the step S100, a data interface is also provided; each temperature sensor is provided with a signal transmission line; first, the data interface is installed on the top of the installation rod, and then the signal transmission line is passed through the The strip-shaped groove is electrically connected to the data interface along the interior of the mounting rod; in the step S300, the data interface is electrically connected to the display processor through a cable.

Optionally, in the step S100, the temperature sensor provided is a platinum resistance temperature sensor.

Optionally, in the step S100, a bottle mouth seal is also provided, and the bottle mouth seal is installed on the upper end of the installation rod.

Compared with the prior art, the method for measuring the liquid level of the low-temperature liquefied gas provided by the embodiment of the present invention has one of the following technical effects: hold the upper end of the installation rod, and install the installation rod perpendicular to the liquid level of the low-temperature liquefied gas on the In the low-temperature liquefied gas, seal the bottle mouth of the low-temperature thermal insulation gas bottle with the bottle mouth seal; let it stand for a period of time to keep the installation rod and the liquid level of the low-temperature liquefied gas relatively stable; put a plurality of the temperature sensors Connect the power supply with the display processor, each temperature sensor transmits the measured temperature value to the display processor, and obtains the temperature difference value of the adjacent two temperature sensors; using low-temperature liquefied gas in gas, The temperature difference existing in the two states of the liquid and the law of temperature change in the gas phase space and the liquid phase space respectively, find out the value of the temperature difference and the value of the sudden change in temperature, and judge according to the height calibrated by the temperature sensor at the sudden change of temperature. The liquid level height of the low-temperature liquefied gas has small error and high measurement accuracy, so that the measurement accuracy of the liquid level of the low-temperature liquefied gas is improved; meanwhile, the structure is simple and the operation is convenient.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a flow chart of the low-temperature liquefied gas liquid level measurement method of the present invention.

FIG. 2 is a schematic structural diagram of the low-temperature liquefied gas liquid level measurement method of the present invention.

FIG. 3 is a schematic exploded schematic diagram of the partial structure of the low-temperature liquefied gas liquid level measurement method of the present invention.

FIG. 4 is a schematic structural diagram of a temperature sensor of the low-temperature liquefied gas liquid level measurement method of the present invention.

Among them, each reference sign in the figure:

Mounting rod 100, data interface 110, strip groove 120, notch 130, bottle seal 140, temperature sensor 200, detection end 210, mounting seat 220, mounting plate 240, adjustment assembly 300, screw 310, nut 311, nut 312, Nut 320.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical" "," "horizontal", "top", "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present invention and simplification It is described, rather than indicated or implied, that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second" may expressly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the embodiments of the present invention, unless otherwise expressly specified and limited, terms such as “installation”, “connection”, “connection”, and “fixation” should be understood in a broad sense. For example, it may be a fixed connection or a It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of the two elements or the interaction relationship between the two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.

In the present invention, referring to Fig. 1 and Fig. 2, a method for measuring the liquid level of low-temperature liquefied gas is provided, comprising the following steps:

S100: Provide a mounting rod 100 and a plurality of temperature sensors 200, and install a plurality of the temperature sensors 200 on the outer wall of the mounting rod 100 sequentially from bottom to top;

S200: Provide a display processor (not shown in the figure) for processing and displaying the data transmitted by the plurality of temperature sensors 200; specifically, the plurality of temperature sensors 200 are connected to the display processor through cables electrical connection;

S300: Hold the upper end of the installation rod 100, and install the installation rod 100 in the low-temperature liquefied gas perpendicular to the liquid level of the low-temperature liquefied gas;

S400: let stand for a period of time to keep the liquid level of the installation rod 100 and the low-temperature liquefied gas relatively stable, so that the low-temperature liquefied gas does not shake;

S500: Power on a plurality of the temperature sensors 200 and the display processor, each of the temperature sensors 100 transmits the measured temperature value to the display processor, and obtains two adjacent temperature sensors The temperature difference value of 200; using the temperature difference of the low-temperature liquefied gas in the two states of gas and liquid, and the temperature change law of the temperature in the gas phase space and the liquid phase space respectively, find out the temperature difference value and the value of the sudden change in temperature, according to the temperature The height calibrated by the temperature sensor 200 at the sudden change determines the liquid level of the low-temperature liquefied gas, with small error and high measurement accuracy, which improves the measurement accuracy of the low-temperature liquefied gas liquid level; meanwhile, the structure is simple and the operation is convenient.

The detailed description is as follows: the liquid level of the liquefied gas is in the interval between the detection ends 210 of the two adjacent temperature sensors 200, and when the liquid level of the liquefied gas is at different positions in the interval, the two adjacent temperature sensors 200 The value of the temperature difference between them will also be different. Therefore, the staff will collect the values during the test phase, that is, the interval is evenly divided into multiple points, and then the liquid level of the liquefied gas is tested at the position of each point. The temperature difference value distribution table between the adjacent two temperature sensors 200 corresponding to each point position in the interval is obtained, and each temperature difference vertical value of the temperature difference value distribution table corresponds to the height value of each point in the longitudinal direction of the installation rod 100 , the above data are recorded in the display processor system in advance. Therefore, in one measurement, the temperature difference value of a group of two temperature sensors 200 is obtained first, then the value with the largest temperature difference is obtained, and finally the liquid level height of the liquefied gas can be accurately obtained by comparing the above-mentioned temperature difference value distribution table.

In the step S300, referring to FIG. 1 and FIG. 2, the installation rod 100 is placed in the low temperature liquefied gas along the direction perpendicular to the liquid level of the warm liquefied gas, and the lower end of the installation rod 100 is extended straight to the low temperature adiabatic gas The bottom of the bottle ensures the accuracy of the measurement.

In the step S400, referring to FIG. 1 and FIG. 2, the period of time is 5s to 20s, to ensure that the liquid level of the low-temperature liquefied gas in the low-temperature adiabatic gas cylinder tends to be in a static state, and to ensure that the temperature sensor 200 can measure the environment in which it is located temperature.

In the step S100 , referring to FIGS. 1 , 3 and 4 , the mounting base 220 of the temperature sensor 200 is provided with a mounting plate 240 , and the mounting plates 240 of the temperature sensors 200 are screwed in sequence from bottom to top. On the outer wall of the mounting rod 100 , there is a longitudinal distance and a radial distance between two adjacent temperature sensors 200 . Therefore, the installation of two adjacent temperature sensors 200 in the longitudinal space of the installation rod 100 will not interfere, so that the longitudinal distance between the detection ends 210 of two adjacent temperature sensors 200 can be set in the range of 0 mm˜10 mm within.

In the step S100, the longitudinal distance is 0 mm to 10 mm. In the application, the distance between the detection ends 210 of two adjacent temperature sensors 200 is determined according to the actual required measurement accuracy or according to the difference in the measured low-temperature liquefied gas. value of . Wherein, the smaller the longitudinal distance between the detection ends 210 of two adjacent temperature sensors 200, the smaller the influence of environmental factors, the smaller the measurement error of the temperature sensors 200, and the higher the measurement accuracy. The operator can set the longitudinal distance between the detection ends 210 of two adjacent temperature sensors 200 to a small value, so that when there is a significant sudden change in the temperature difference between two adjacent temperature sensors 200, The liquid level height of liquefied gas can be obtained more accurately, and the smaller the measurement error, the higher the measurement accuracy.

Referring to FIG. 1 , FIG. 3 and FIG. 4 , the temperature sensor 200 is electrically connected to the data interface 110 through a signal transmission line. The data interface 110 is electrically connected with the display processor through a transmission line, so as to realize data transmission and make wiring convenient for the staff.

In the step S100 , referring to FIGS. 1 , 3 and 4 , a plurality of adjustment components 300 are also provided, and each of the adjustment components 300 is set corresponding to one of the temperature sensors 200 . The adjustment assembly 300 includes a bolt 310 and a nut 320 . The mounting rod 100 is a hollow rod, and the outer wall of the mounting rod 100 is provided with a plurality of longitudinally distributed strip-shaped grooves 120 , each strip-shaped groove 120 corresponds to one of the temperature sensors 200 ; the mounting plate 140 A mounting hole is provided through the upper part.

Referring to FIG. 1 , FIG. 3 and FIG. 4 , firstly connect the screw rod 311 of the bolt 310 to the strip groove 120 so that the nut 312 of the bolt 300 is limited by the strip groove 120 to the installation position Inside the rod 100, the mounting hole of the mounting plate 240 is sleeved on the screw rod 311 of the bolt 310, then the nut 320 is threadedly connected to the screw rod 311 of the screw bolt 310, and finally the nut 320 is tightened. The mounting plate 240 is fixed on the bolts 310 . The specific operation steps are as follows: loosen the nut 320 , move the mounting plate 240 and the bolt 310 up or down along the strip groove 120 , and adjust the distance between the detection ends 210 of two adjacent temperature sensors 200 . When the longitudinal distance is the set value, tighten the nut 320 so that the mounting seat 220 of the temperature sensor 200 is in contact with the outer wall of the mounting rod 100, and the nut 312 of the bolt 310 is in contact with the inner wall of the mounting rod 100. The temperature sensor 200 is fixed, the adjustment is convenient, and the connection is stable.

In the step S100 , referring to FIGS. 1 , 3 and 4 , the outer wall of the mounting rod 100 is provided with a notch 130 at the top or bottom of the strip groove 120 , and the nut 312 of the bolt 310 is first Pass through the gap 130, and then movably connect the screw 311 of the bolt 310 to the strip groove 120, so that the nut 312 of the bolt 310 can pass through the gap 130, so that the screw 311 of the bolt 310 can be inserted into the The strip groove 120 is easy to install.

In the step S100, referring to FIG. 1, FIG. 3 and FIG. 4, a data interface 110 is also provided. Each of the temperature sensors 200 is provided with a signal transmission line (not shown); the data interface 110 is first installed on the top of the mounting rod 100 , and then the signal transmission line is passed through the strip groove 112 along the The inside of the installation rod 100 is electrically connected to the data interface 110 to avoid confusion when the signal transmission line is arranged on the outer wall of the installation rod 100, and at the same time, the signal transmission line is arranged inside the installation rod 100, so that the low-temperature liquefied gas level can be measured. The structure of the method is compact and concise. In the step S300, the data interface 110 is electrically connected to the display processor through a cable to facilitate connection.

In the step S100, the temperature sensor 200 provided is a platinum resistance temperature sensor. The platinum resistance temperature sensor is a mature existing technology. The platinum resistance temperature sensor uses the characteristic that the resistance value of metal platinum changes when the temperature changes to measure the temperature, and the display meter will indicate the resistance value of the platinum resistance resistance. the corresponding temperature value. At the same time, platinum resistance temperature sensor is the most accurate and stable temperature sensor, and its linearity is better than that of thermocouple and thermistor.

3 and 4 , in the step S100 , a bottle mouth seal 140 is further provided, and the bottle mouth seal 140 is installed on the upper end of the installation rod 100 . In the step S300, hold the upper end of the installation rod 100, install the installation rod 100 in the low-temperature liquefied gas perpendicular to the liquid surface of the low-temperature liquefied gas, and then install the bottle seal 140 Seal the bottle mouth of the low-temperature insulating gas bottle (not shown in the figure) containing the low-temperature liquefied gas to prevent the low-temperature liquefied gas from diffusing to the outside of the low-temperature liquefied gas. The bottle mouth seal 140 is made of silica gel or rubber, and the bottle mouth of the cryogenic liquid is blocked by the bottle mouth seal 140, so that the bottle mouth is sealed, and the operation is convenient.

Wherein, the display processor (not shown in the figure) is a mature prior art, so its structure and working principle are not described in detail in the present invention.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, its architectural form can be flexible and changeable, and a series of products can be derived. Just making some simple deductions or substitutions should be regarded as belonging to the scope of patent protection of the present invention determined by the submitted claims.

Claims (10)

1. a low temperature liquefied gas liquid level measurement method, is characterized in that, comprises the following steps: S100: Provide a mounting rod and a plurality of temperature sensors, and install the plurality of temperature sensors on the mounting rod in sequence from bottom to top; S200: Provide a display processor for processing and displaying the data transmitted from the plurality of temperature sensors; S300: Hold the upper end of the installation rod, and install the installation rod in the low-temperature liquefied gas perpendicular to the liquid level of the low-temperature liquefied gas; S400: stand for a period of time to keep the liquid level of the installation rod and the low-temperature liquefied gas relatively stable; S500: Power on a plurality of the temperature sensors and the display processor, each of the temperature sensors transmits the measured temperature value to the display processor, and obtains a temperature difference between two adjacent temperature sensors Numerical value; using the temperature difference of low-temperature liquefied gas in gas and liquid states, and the law of temperature change in gas phase space and liquid phase space respectively, find out the value of temperature difference and the value of sudden change in temperature, according to the change of temperature The height calibrated by the temperature sensor determines the liquid level of the low-temperature liquefied gas. 2 . The method for measuring the liquid level of low-temperature liquefied gas according to claim 1 , wherein in the step S300 , the installation rod is placed on the low-temperature liquefied gas along a direction perpendicular to the liquid level of the warm liquefied gas. 3 . , and the lower end of the installation rod extends straight to the bottom of the low-temperature heat-insulating gas cylinder. 3 . The method for measuring the liquid level of low-temperature liquefied gas according to claim 1 , wherein in the step S300 , the period of time is 5s˜20s. 4 . 4. The method for measuring the liquid level of low-temperature liquefied gas according to any one of claims 1-3, wherein in the step S100, the mounting seat of the temperature sensor is provided with a mounting plate, and a plurality of said The mounting plate of the temperature sensor is screwed on the outer wall of the mounting rod in sequence from bottom to top, and there is a longitudinal distance and a radial distance between the detection ends of two adjacent temperature sensors. 5 . The method for measuring the liquid level of low-temperature liquefied gas according to claim 4 , wherein in the step S100 , a plurality of adjustment components are also provided, and each of the adjustment components corresponds to one of the temperature sensors; 6 . The adjustment assembly includes bolts and nuts; the installation rod is a hollow rod, and the outer wall of the installation rod is provided with several longitudinally distributed strip grooves, each of which corresponds to one of the temperature sensors; the installation Mounting holes are provided through the board; First, the screw of the bolt is movably connected to the strip groove, so that the nut of the bolt is limited by the strip groove in the installation rod, and then the installation hole is sleeved on the bolt Then, the nut is threadedly connected to the screw rod of the bolt, and finally the nut is tightened to fix the mounting plate on the bolt. 6. The method for measuring the liquid level of low-temperature liquefied gas according to claim 5, wherein in the step S100, the outer wall of the installation rod is provided with a gap at the top or bottom of the strip groove, and the first The nut of the bolt passes through the gap, and the screw rod of the bolt is movably connected to the strip groove. 7 . The method for measuring the liquid level of low-temperature liquefied gas according to claim 4 , wherein in the step S100 , the longitudinal spacing is 0 mm˜10 mm. 8 . 8. The low-temperature liquefied gas liquid level measurement method according to claim 5, characterized in that: in the step S100, a data interface is also provided; each of the temperature sensors is provided with a signal transmission line; the data interface is installed first On the top of the installation rod, the signal transmission line is passed through the strip-shaped groove and is electrically connected to the data interface along the interior of the installation rod; in the step S300, the data interface is passed through the wire A cable is electrically connected to the display processor. 9 . The method for measuring the liquid level of low-temperature liquefied gas according to claim 1 , wherein in the step S100 , the temperature sensor provided is a platinum resistance temperature sensor. 10 . 10. The method for measuring the liquid level of low-temperature liquefied gas according to any one of claims 1-3, wherein in the step S100, a bottle mouth seal is also provided, and the bottle mouth seal is installed on the the upper end of the mounting rod.

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