Multifunctional high-precision embedded digital thermometer replacing precise mercurial thermometer

Abstract

The invention discloses a multifunctional high-precision embedded digital thermometer for replacing a precise mercurial thermometer. The multifunctional high-precision embedded digital thermometer is divided into a display complete machine with the resolution of 0.01 DEG C and the display complete machine with the resolution of-40 DEG C to 120 DEG C and a display complete machine with the resolution of 0 DEG C to 300 DEG C; the sensors of different specifications are embedded into a display complete machine of a full-scale temperature specification; the multifunctional high-precision embedded digital thermometer comprises a display unit, a control unit, a power supply, an A / D conversion unit and an NTC and compensation resistor unit. The control unit is electrically connected to the A / D conversion unit and the power supply; and the A / D conversion unit is electrically connected to the NTC and compensation resistor unit. The multifunctional high-precision embedded digital thermometer capable of replacing the precise mercurial thermometer can effectively replace the precise mercurial thermometer, and is wide in application range and economical in cost.

Description

Technical Field

[0001] The invention relates to the technical field of temperature measurement, in particular to a multifunctional high-precision embedded digital thermometer replacing a precise mercury thermometer. Background Art

[0002] The production and use of mercury thermometers have a history of hundreds of years. In the process of production and use, mercury pollution is inevitable. It is imperative to replace them with electronic technology. However, there are first- and second-class standards for precision mercury thermometers, four series of precision thermometers, meteorological, dry-bulb and petroleum, five categories and 295 temperature specifications. It is very difficult to replace them completely. Although there are high-precision digital thermometers made with platinum resistors as temperature sensing elements, their prices are as high as thousands of yuan, making them difficult to popularize and promote. Under the condition that electronic products are difficult to replace, in recent years, the German company Ulabo has launched a precision laboratory glass thermometer made of blue organic fillers to replace mercury. There are 11 series and 211 temperature specifications. It is difficult to replace them because they are slower in sensing temperature and have high prices. This also reflects from the side that electronic technology is unsustainable today.

[0003] The production and use of mercury thermometers will bring about mercury pollution. In particular, mercury evaporates into mercury vapor under normal temperature conditions and is easily dissolved into the air, water and soil, thus causing immeasurable harm to the human living environment. As early as 2013, the World Health Organization proposed that all countries sign the "Minamata Convention", stipulating that the production and use of all mercury thermometers should be banned from 2015 to 2020. Since there was no ideal product to replace it during this period, it was forced to be extended for five years to 2020-2025. As the deadline is approaching, the replacement situation is quite severe. This patented product will make a contribution to the fulfillment of the contract and environmental protection. Summary of the invention

[0004] The present invention aims to solve the above technical problems and provide a multifunctional high-precision embedded digital thermometer that can replace the precision mercury thermometer, which can effectively replace the precision mercury thermometer, has a wide range of applications and is cost-effective.

[0005] In order to solve the above technical problems, the embodiment of the present invention provides a multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer. The multifunctional high-precision embedded digital thermometer is divided into two display units with a resolution of 0.01°C and a display unit of -40°C to 120°C and 0°C to 300°C;

[0006] Embed sensors of different specifications into a display unit that can display the full range of temperature specifications;

[0007] The multifunctional high-precision embedded digital temperature meter comprises: a display unit, a control unit, a power supply, an A / D conversion unit, and an NTC plus compensation resistance unit;

[0008] The control unit is electrically connected to the A / D conversion unit and the power supply;

[0009] The A / D conversion unit is electrically connected to the NTC plus compensation resistor unit.

[0010] For the multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer provided by the present invention, the range and temperature technical specifications of the embedded temperature sensor of the multifunctional high-precision embedded digital thermometer are: the 100°C range is controlled within ±0.5°C, the 50°C range is controlled within ±0.1°C, the 30°C range is controlled within ±0.03°C, the 20°C range is controlled within ±0.02°C, and the 10°C range is controlled within ±0.01°C.

[0011] For the multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer provided by the present invention, in the NTC plus compensation resistor unit, the NTC temperature sensor approaches the central value of the thermistor through a series-parallel form.

[0012] For the multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer provided by the present invention, the NTC temperature sensor of the NTC plus compensation resistor unit is detachably mounted on the display unit.

[0013] The following gives the temperature error table of the thermistor with ±0.05% in each range after parallel resistor compensation:

[0014]

[0015]

[0016]

[0017] As can be seen from the above table, the temperature error values of the thermistor with ±0.05% in different range are relatively small. The following gives the temperature error comparison table of the thermistor with ±0.05% in different ranges:

[0018]

[0019] The present invention has the following beneficial effects: The multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer provided by the present invention can effectively replace the precision mercury thermometer, has a wide range of applications, and is cost-effective. Description of the Drawings

[0020] Figure 1 It is the circuit schematic diagram of the multifunctional high-precision embedded digital thermometer that replaces the precision mercury thermometer in the embodiment of the present invention. Detailed Embodiment

[0021] In order to make the technical means, creative features, achieved objectives and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0022] An embodiment of the present invention provides a multi-functional high-precision embedded digital thermometer to replace a precision mercury thermometer. The multi-functional high-precision embedded digital thermometer is divided into two display units with a resolution of 0.01 °C, one for -40 °C to 120 °C and the other for 0 °C to 300 °C. Sensors of different specifications are embedded in the display units with full-range temperature specifications. Here, the sensor is an NTC temperature sensor. The display methods can be divided into wired, wireless and mobile phone types. Any one of the display methods can fully replace the high-precision mercury thermometer within the temperature specifications of these two display units.

[0023] See Figure 1 , the multi-functional high-precision embedded digital thermometer includes a display unit, a control unit, a power supply, an A / D conversion unit, and an NTC plus compensation resistor unit. Here, the NTC plus compensation resistor unit is the core part of the present invention. In the multi-functional high-precision embedded digital thermometer provided by the present invention to replace a precision mercury thermometer, the two display units are set with sub-ranges, that is, a first display unit with a resolution of 0.01 °C for -40 °C to 120 °C and a second display unit with a resolution of 0.01 °C for 0 °C to 300 °C, effectively meeting the actual needs through the first display unit and the second display unit.

[0024] The internal structures of the first display unit and the second display unit can be seen in Figure 1 , in the present invention, the display unit uses an LED display screen, and the control module as the main control center uses an AT89C51 single-chip microcomputer. The AT89C51 single-chip microcomputer can be powered by a dry battery or a lithium battery. The AT89C51 single-chip microcomputer is connected to an A / D conversion unit. The A / D conversion unit connected to the AT89C51 single-chip microcomputer belongs to the prior art and will not be elaborated here.

[0025] It is worth mentioning that one of the important structures of each display unit lies in the NTC plus compensation resistor unit. In the NTC plus compensation resistor unit, the display unit for -40 °C to 120 °C uses a thermistor (i.e., an NTC temperature sensor) with a specification of 30Kohms 37degc from Shanghai Minglai Electronic Technology Co., Ltd., and the display unit for 0 °C to 300 °C uses a thermistor (i.e., an NTC temperature sensor) with the specification of MRMF58B104F3950 from Shanghai Minglai Electronic Technology Co., Ltd.

[0026] It should be noted that the range and temperature technical indicators (errors) of the embedded temperature sensor in the multifunctional high-precision embedded digital thermometer are as follows: for the 100°C range, it is controlled within ±0.5°C; for the 50°C range, it is controlled within ±0.1°C; for the 30°C range, it is controlled within ±0.03°C; for the 20°C range, it is controlled within ±0.02°C; for the 10°C range, it is controlled within ±0.01°C.

[0027] For the multifunctional high-precision embedded digital thermometer provided by the present invention to replace the precision mercury thermometer, in the NTC plus compensation resistor unit, the NTC temperature sensor approaches the central value of the thermistor through a series-parallel connection form.

[0028] For the multifunctional high-precision embedded digital thermometer provided by the present invention to replace the precision mercury thermometer, the NTC temperature sensor of the NTC plus compensation resistor unit is detachably installed on the display unit.

[0029] By dividing each of the two display units into five range intervals, the commercial needs can be effectively met. The information about the two display units that can replace the precision mercury thermometer is as follows:

[0030] -40 to 120°C display unit replaces the precision mercury thermometer (petroleum)

[0031]

[0032] -30 to 300°C display unit replaces the precision mercury thermometer (petroleum)

[0033] Range Model Name Temperature measurement range Graduation value Range 100℃ 86C Outlet temperature of fuel tank 95～175℃ 1℃ 80℃ 50℃ 104C Solvent distillation 173～227℃ 0.2℃ 54℃ 30℃ 96C For solidification point 120～150℃ 0.1℃ 30℃ 20℃ GB63 Strong thermal stability 130～145℃ 0.5℃ 15℃ 10℃ GB64 Strong oxidation stability 195～205℃ 0.1℃ 10℃

[0034] The following gives Table 1 of the temperature error values after parallel resistance for the 10°C range greater than the central value.

[0035] Table 1 Temperature error values after parallel resistance for the 10°C range greater than the central value

[0036]

[0037] The following gives Table 2 of the error values after series resistance compensation for the 10°C range less than the central value.

[0038] Table 2 Error values after series resistance compensation for the 10°C range less than the central value

[0039]

[0040] The above are all the errors after compensation for the ±5% thermistor, and currently the market can provide ±0.05% thermistors, that is, from the original 37°C ±150Ω, it is reduced to ±15Ω, which means the temperature error can be reduced by ten times, and all can exceed the error of the precision mercury thermometer.

[0041] The following gives Table 3 of the temperature error after parallel resistors for a 100°C range greater than the central value.

[0042] Table 3 Numerical Table of Temperature Error after Parallel Resistors for a 100°C Range Greater than the Central Value (±0.5°C)

[0043]

[0044] The following gives Table 4 of the error values after series resistor compensation for a 100°C range less than the central value.

[0045] Table 4 Numerical Table of Error Values after Series Resistor Compensation for a 100°C Range Less than the Central Value (±0.5°C)

[0046]

[0047] The varieties and specifications involved in the present invention are as follows: Overall technical indicators: -40 - 125°C, resolution 0.01°C. Embedding sensors of different ranges and specifications can replace the corresponding precision mercury thermometers, totaling 75 types (petroleum). The replaceable specifications, range, and error are as follows:

[0048]

[0049] The above totals 75 types.

[0050] 100°C range

[0051]

[0052] 50°C range

[0053]

[0054]

[0055] 30°C range

[0056]

[0057] 20°C range

[0058]

[0059]

[0060] 10°C range

[0061]

[0062]

[0063] The following is the temperature error table of series-parallel connection at 34 - 40℃ with Engler viscosity of 18C for petroleum experiments:

[0064]

[0065]

[0066]

[0067] It can be seen from the above table that by approximating the central value through the corresponding series and parallel resistors, the error can be reduced. The above table is a discrete type of ±0.5%. By refined grading, 30KΩ ± 150Ω at 37℃ can be reduced to ±15Ω, and the error can be reduced by ten times. This method is applicable to other specifications as well.

[0068] Those of ordinary skill in the art can understand that the above embodiments are specific examples for implementing the present invention. In practical applications, various changes can be made in form and details without departing from the spirit and scope of the present invention.

Claims

1. A multifunctional high-precision embedded digital thermometer that replaces a precision mercury thermometer, characterized in that: This multifunctional high-precision embedded digital thermometer is divided into two display units with a resolution of 0.01℃, ranging from -40℃ to 120℃ and 0℃ to 300℃; Embed sensors of different specifications into a display unit that can display the full range of temperature specifications; The multifunctional high-precision embedded digital temperature meter comprises: a display unit, a control unit, a power supply, an A / D conversion unit, and an NTC plus compensation resistance unit; The control unit is electrically connected to the A / D conversion unit and the power supply; The A / D conversion unit is electrically connected to the NTC plus compensation resistance unit.

2. The multifunctional high-precision embedded digital thermometer replacing the precision mercury thermometer according to claim 1 is characterized in that: The measuring range and temperature technical indicators of the embedded temperature sensor of the multifunctional high-precision embedded digital thermometer are: 100℃ range is controlled at ±0.5℃, 50℃ range is controlled at ±0.1℃, 30℃ range is controlled at ±0.03℃, 20℃ range is controlled at ±0.02℃, and 10℃ range is controlled at ±0.01℃.

3. The multifunctional high-precision embedded digital thermometer replacing the precision mercury thermometer according to claim 1 is characterized in that: In the NTC plus compensation resistor unit, the NTC temperature sensor approaches the center value of the thermistor in a series-parallel connection.

4. The multifunctional high-precision embedded digital thermometer replacing the precision mercury thermometer according to claim 1 is characterized in that: The NTC temperature sensor of the NTC plus compensation resistor unit is detachably mounted on the display device.

Images