CN205139064U - LNG evaporation rate's measurement system - Google Patents

Abstract

The utility model relates to a measurement system for the evaporation rate of LNG, which comprises a low-temperature thermal resistance sensor and a data acquisition system. The data acquisition system comprises a data acquisition module, a data conversion module, a low-voltage power supply module and a PC, and the low-temperature thermal resistance sensor is sequentially connected with the data acquisition module. , the data conversion module is connected with the PC, and the low-voltage power supply module is respectively connected with the data acquisition module and the data conversion module. The beneficial effect of the utility model is that the low-temperature liquid level that changes with time can be quickly measured, and then the quality of evaporation in a short period of time can be obtained through the liquid level, and the average evaporation rate in a certain period of time can be calculated. The utility model is not disturbed by external environmental factors, and has potential application value in the engineering application of LNG leakage fire protection.

Description

A Measuring System of LNG Evaporation Rate

technical field

The utility model belongs to the technical field of measurement control and relates to a measurement system for the evaporation rate of LNG.

Background technique

At present, the measurement of LNG evaporation rate is mainly through the load cell. The advantage is that the rate of change of mass can be measured quickly, requiring only simple mathematical calculations. The disadvantage is that the weighing of the load cell is greatly disturbed by external factors. During the weighing process, due to the freezing of water vapor in the air condensed by LNG and attached to the weighing system, the weight error of the weighing becomes larger, and the low temperature characteristics of LNG will cause Make the accuracy of the load cell worse. At the same time, it is not convenient for practical engineering applications. For example, it is difficult to measure with a load cell arrangement in a large LNG leakage collection tank. Even if it is possible, it will cost a lot of money.

Utility model content

The purpose of the utility model is to provide a measurement system for the evaporation rate of LNG, which solves the problems of large measurement errors and easy infection by external environmental factors in the prior art.

The technical scheme adopted by the utility model is that a measurement system for the evaporation rate of LNG includes a low-temperature thermal resistance sensor and a data acquisition system, and the data acquisition system includes a data acquisition module, a data conversion module, a low-voltage power supply module and a PC, The low-temperature thermal resistance sensor is sequentially connected with the data acquisition module, the data conversion module and the PC, and the low-voltage power supply module is respectively connected with the data acquisition module and the data conversion module.

The low-temperature thermal resistance sensors are densely arranged in a circular upward equidistant manner in a cylindrical container, and the vertical distance between the probe axes of two adjacent low-temperature thermal resistance sensors is less than 1cm.

The beneficial effect of the utility model is that the low-temperature liquid level that changes with time can be measured by the low-temperature thermal resistance, and then the quality of evaporation in a short period of time can be obtained through the liquid level, and the average evaporation rate in a certain period of time can be calculated. The dense thermal resistance arrangement can effectively calculate the LNG evaporation amount and average evaporation rate in each period, and then through the drawing of the dot-line diagram, the change of the LNG evaporation rate can be intuitively expressed. The utility model is not disturbed by external environmental factors, and has potential application value in the engineering application of LNG leakage fire protection.

Description of drawings

Fig. 1 is a structural block diagram of a measurement system for LNG evaporation rate of the present invention.

In the figure, 1. Low temperature thermal resistance sensor, 2. Data acquisition module, 3. Data conversion module, 4. Low voltage power supply module, 5. PC, 6. Cylindrical container.

detailed description

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

A measurement system for LNG evaporation rate of the utility model, as shown in Figure 1, includes a low-temperature thermal resistance sensor 1 and a data acquisition system, and the data acquisition system includes a data acquisition module 2, a data conversion module 3, a low-voltage power supply module 4 and a PC 5. The low temperature thermal resistance sensor 1 is sequentially connected with the data acquisition module 2, the data conversion module 3 and the PC 5, and the low voltage power supply module 4 is respectively connected with the data acquisition module 2 and the data conversion module 3.

A plurality of low temperature thermal resistance sensors 1 are densely arranged in a cylindrical container 6 at equal intervals upward in a ring shape, and the vertical distance between the probe axes of two adjacent low temperature thermal resistance sensors 1 is less than 1 cm.

The measurement system of the LNG evaporation rate of the utility model arranges the low-temperature thermal resistance sensors 1 circularly upward hcm equidistantly in the columnar container 6, in order to measure a more accurate evaporation rate, here every two adjacent sensor probe axes The vertical spacing h should be less than 1cm, and the smaller the value of h, the more accurate the measured evaporation rate. Inside the columnar container 6 is the LNG leakage collection tank; the low temperature thermal resistance sensor 1 is numbered, from the bottom to the top respectively TC1, TC2, ..., TCn, the interval between each sensor is preferably hcm; the low temperature thermal resistance The sensor 1 is connected to the signal input port of the data acquisition module 2 by a low temperature resistant lead wire, the signal output port of the data acquisition module 2 is connected to the signal input port of the data conversion module 3, and the signal output port of the data conversion module 3 is connected to the PC 5, PC Machine 5 monitors and records temperature data; connects data acquisition module 2 and data conversion module 3 with low-voltage power supply module 4, and low-voltage power supply module 4 is connected to normal 220V voltage, and outputs 20V low-voltage voltage after module conversion ;

The resistance value of the low temperature thermal resistance sensor 1 changes with the change of the ambient temperature, that is, there is a certain linear relationship between the resistance value and the ambient temperature; When it evaporates and exposes the liquid surface, the measured temperature displayed on the PC 5 will increase accordingly, so that the change of the liquid level can be monitored, and the change of the liquid level can obtain the corresponding change of the liquid quality;

The arrangement of dense low-temperature thermal resistance sensors 1 can more accurately obtain the change of the liquid level in a short period of time, and the evaporation of the liquid in a short period of time can be obtained; as the evaporation time changes, the sensors are exposed to the liquid surface one by one, according to The LNG quality calculated by the distance between each sensor and the time difference between the sensors separated from the liquid surface can be used to obtain the average evaporation rate of LNG in each time period; the denser the sensors are, the more accurate the evaporation rate can be obtained; when the evaporation process is over , according to the recorded temperature change points of each sensor, calculate the corresponding evaporation rate;

The average evaporation rate of each time period is plotted into a dotted line graph to directly reflect the change of evaporation rate.

Claims (2)

1. A measurement system for LNG evaporation rate, characterized in that it includes a low-temperature thermal resistance sensor (1) and a data acquisition system, and the data acquisition system includes a data acquisition module (2), a data conversion module (3), a low-voltage power supply module (4) and PC (5), the low-temperature thermal resistance sensor (1) is sequentially connected with the data acquisition module (2), data conversion module (3) and PC (5), and the low-voltage power supply module (4 ) are respectively connected with the data acquisition module (2) and the data conversion module (3). 2. The system for measuring the evaporation rate of LNG according to claim 1, characterized in that, the low temperature thermal resistance sensors (1) are arranged densely in a cylindrical container (6) in a circular upward equidistant manner, The vertical distance between the probe axes of two adjacent low-temperature thermal resistance sensors (1) is less than 1 cm.