Thermostatic water bath assembly and performance test

Experimenter: Chen Xiaohui   Zhou Jin   Su Zhu Xie Jiayu


Thermostatic water bath assembly and performance test

The purpose of the experiment is to understand the structure and working principle of the constant temperature water bath, learn the assembly technology of the constant temperature water bath, and the sensitivity curve of the constant temperature water bath. Master the adjustment technology and use method of the Beckmann thermometer. What are the main factors affecting the sensitivity of the constant temperature bath? .

Answer: The factors affecting sensitivity are related to the working medium, temperature sensing element, stirring speed, heater power, and physical properties of the relay.

If the stirring speed is not regular, the temperature of the constant temperature water bath is relatively large at the set temperature, and the measured sensitivity is low. If the heater power is not suitable, it is difficult to control the temperature of the water bath, so that the set temperature fluctuates greatly, and the sensitivity is low. If the accuracy of the Beckman thermometer is low, the temperature change values ​​recorded at different times will be large, that is, the water bath temperature fluctuates greatly at the set temperature, the sensitivity is low, and the temperature sensing effect of the contact thermometer is poor, higher than At the set temperature, the heater does not stop heating, so that the bath temperature is constant and high, so that the temperature of the water bath is recorded at a high time and the sensitivity is low. What measures should be taken to improve the temperature control accuracy of the constant temperature bath?

Answer: To improve the sensitivity of the constant temperature bath, it is necessary to aim at the precision of the influencing factors.

A moderately-powered heater, a high-precision Beckman thermometer, and a thermometer with good contact performance. The agitation speed of the agitator should be fixed at a moderate value while selecting the appropriate working medium according to the constant temperature range.

Experimental discussion

In this experiment, the temperature rises rapidly when the heater is heated, so we need to be quick and accurate when reading, otherwise the data error will be very large.

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Thermostatic water bath assembly and performance test

The purpose of the experiment is to understand the structure and working principle of the constant temperature water bath, learn the assembly technology of the constant temperature water bath, and the sensitivity curve of the constant temperature water bath. Master the adjustment technology and use method of the Beckmann thermometer. What are the main factors affecting the sensitivity of the constant temperature bath? .

Answer: The factors affecting sensitivity are related to the working medium, temperature sensing element, stirring speed, heater power, and physical properties of the relay.

If the stirring speed is not regular, the temperature of the constant temperature water bath is relatively large at the set temperature, and the measured sensitivity is low. If the heater power is not suitable, it is difficult to control the temperature of the water bath, so that the set temperature fluctuates greatly, and the sensitivity is low. If the accuracy of the Beckman thermometer is low, the temperature change values ​​recorded at different times will be large, that is, the water bath temperature fluctuates greatly at the set temperature, the sensitivity is low, and the temperature sensing effect of the contact thermometer is poor, higher than At the set temperature, the heater does not stop heating, so that the bath temperature is constant and high, so that the temperature of the water bath is recorded at a high time and the sensitivity is low. What measures should be taken to improve the temperature control accuracy of the constant temperature bath?

Answer: To improve the sensitivity of the constant temperature bath, it is necessary to aim at the precision of the influencing factors.

A moderately-powered heater, a high-precision Beckman thermometer, and a thermometer with good contact performance. The agitation speed of the agitator should be fixed at a moderate value while selecting the appropriate working medium according to the constant temperature range.

Experimental discussion

In this experiment, the temperature rises rapidly when the heater is heated, so we need to be quick and accurate when reading, otherwise the data error will be very large.

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3 data processing:

4 thinking

What are the main factors affecting the sensitivity of the thermostatic bath?

Answer: The factors affecting sensitivity are related to the working medium, temperature sensing element, stirring speed, heater power, and physical properties of the relay. If the heater power is too large or too low, it is difficult to control the temperature of the water bath so that its temperature fluctuates greatly above and below the set temperature, and its sensitivity is low; if the stirring speed is high or low, or is always too low, the constant temperature water bath The temperature fluctuates up and down at the set temperature, and the measured sensitivity is low. If the accuracy of the Beckman thermometer is low, the difference in temperature change recorded at different times is large, that is, the temperature of the water bath fluctuates greatly at the set temperature, and the sensitivity is low. Similarly, the temperature sensing effect of the contact thermometer is poor. When the temperature is higher than the set temperature, the heater does not stop heating, so that the bath temperature drops slowly, so that the recording bath temperature fluctuates greatly at the set temperature in different time, and the measured sensitivity is low.

What measures should be taken to improve the temperature control accuracy of the constant temperature bath?

Answer: To increase the sensitivity of the constant temperature bath, use a moderately sized heater, a high-precision Beckman thermometer contact thermometer, and a stirrer with a mercury thermometer. The stirring speed should be fixed at a moderate value, and at the same time according to the constant temperature. Range Select the appropriate working medium.

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Shenzhen University Physical Chemistry Experiment Report

Experimenter: Xie Jiazhen, Su Zhu Experimental time: 2000/5/17

Temperature: 21.7 °C Atmospheric pressure: 101.7 kPa

Thermostatic water bath assembly and performance test

Objective To understand the structure and construction principle of constant temperature water bath, learn the assembly technology of constant temperature water bath, measure the sensitivity curve of constant temperature water bath, and master the adjustment technology and correct use method of Beckmann thermometer. Instruments and reagents

5 liter beaker Beckman thermometer precision thermometer heater

Mercury contact thermometer relay stirrer transformer

Experimental instrument map

4 experimental data and its processing

Table 1 Temperature change of constant temperature water bath under different conditions, °C

Figure 1 Sensitivity curve of constant temperature water bath under different conditions

discuss

5.1 Factors affecting sensitivity are related to the working medium, temperature sensing element, stirring speed, heater power, and physical properties of the relay. If the heater power is too large or too low, it is difficult to control the temperature of the water bath so that its temperature fluctuates greatly above and below the set temperature, and its sensitivity is low; if the stirring speed is high or low, or is always too low, the constant temperature water bath The temperature fluctuates up and down at the set temperature, and the measured sensitivity is low. If the accuracy of the Beckman thermometer is low, the difference in temperature change recorded at different times is large, that is, the temperature of the water bath fluctuates greatly at the set temperature, and the sensitivity is low. Similarly, the temperature sensing effect of the contact thermometer is poor. When the temperature is higher than the set temperature, the heater does not stop heating, so that the bath temperature drops slowly, so that the recording bath temperature fluctuates greatly at the set temperature in different time, and the measured sensitivity is low.

5.2 In order to improve the sensitivity of the constant temperature bath, a moderately-powered heater, a high-precision Beckman thermometer contact thermometer, and a stirrer used in the mercury thermometer should be fixed at a moderate value, and at the same time according to the constant temperature range. Select the appropriate working medium.