Application misunderstandings of bimetal thermometers
2022-09-16
Bimetal thermometers and rod-shaped liquid-in-glass thermometers have similar uses, but can be used under conditions where greater mechanical strength is required. And has: waterproof, anti-corrosion, vibration resistance, intuitive, easy to read, mercury-free, durable and so on. It can replace many other forms of temperature measuring instruments and is widely used in petroleum, chemical, machinery, shipbuilding, power generation, textile, printing and dyeing, food and other industries and scientific research departments.
In practical applications, the protective pipes are 1Gr18Ni9Ti stainless steel and molybdenum-titanium, which have strong pressure-bearing and anti-corrosion capabilities.
The bimetal thermometer is that when the bimetal piece feels the temperature change, the pointer can indicate the temperature on a circular graduation scale, and the data can be read directly, which is very intuitive and convenient. However, in the application, it is necessary to pay attention to the misunderstanding of bimetals, so as not to affect the accuracy of the measurement results. Then let's take a look at the misunderstanding of the application of bimetal thermometers.
1. High temperature range:
The temperature measurement range of the bimetal thermometer is 200~650℃, and the allowable error is about 1% of the scale range. In fact, this is wrong, because this kind of metal sheet is made into a spiral-shaped thermal conductivity sensor, which is easy to fatigue at a high temperature of 650 °C, and the temperature difference is very large. Therefore, when the temperature exceeds 550 °C, a thermocouple should be considered to solve this problem. question.
2. Low temperature range
The temperature range of the bimetal thermometer is 200~650°C (this is incorrect), and the low temperature can be measured to -40°C. In fact, this is not much, because bimetal thermometers are usually calibrated at -20 ℃ in production.
In practical applications, the protective pipes are 1Gr18Ni9Ti stainless steel and molybdenum-titanium, which have strong pressure-bearing and anti-corrosion capabilities.
The dial structure forms are: axial type, radial type, 135 degree type, universal type and other varieties, which are suitable for various on-site installation needs. Attention should be paid to the use and maintenance: During the storage, installation, use and transportation of the bimetal thermometer, the collision protection tube should be avoided as much as possible, and the protection tube should not be bent or deformed. During installation, it is strictly forbidden to twist the instrument shell. The instrument is best to work within the ambient temperature of -30 ℃ ~ 80 ℃.
The bimetal thermometer is that when the bimetal piece feels the temperature change, the pointer can indicate the temperature on a circular graduation scale, and the data can be read directly, which is very intuitive and convenient. However, in the application, it is necessary to pay attention to the misunderstanding of bimetals, so as not to affect the accuracy of the measurement results. Then let's take a look at the misunderstanding of the application of bimetal thermometers.
1. High temperature range:
The temperature measurement range of the bimetal thermometer is 200~650℃, and the allowable error is about 1% of the scale range. In fact, this is wrong, because this kind of metal sheet is made into a spiral-shaped thermal conductivity sensor, which is easy to fatigue at a high temperature of 650 °C, and the temperature difference is very large. Therefore, when the temperature exceeds 550 °C, a thermocouple should be considered to solve this problem. question.
2. Low temperature range
The temperature range of the bimetal thermometer is 200~650°C (this is incorrect), and the low temperature can be measured to -40°C. In fact, this is not much, because bimetal thermometers are usually calibrated at -20 ℃ in production.
