How to use a pressure thermometer
1. The first is to look at the appearance
The protective glass or other transparent materials used in the pressure thermometer should be transparent, and there should be no defects or damages that hinder the correct reading; the parts should be firmly assembled without loosening, rust, obvious corrosion and anti-corrosion layer peeling off. The scales, numbers and other marks on the dial of the thermometer should be complete, clear and accurate. The electric contact thermometer should also indicate the rated power of the contact, the high voltage of the contact, and the large working current of AC and DC on the dial or shell, and the grounding terminal has a grounding mark.
2. Next is the measurement method of the pressure thermometer
(1) Optional instrument. The stainless steel pressure thermometer is selected according to the temperature value of the measured process parameter. Selection principle: The normal working temperature of the thermometer should be 1/2 to 3/4 of the range. The temperature bulb of the pressure thermometer cannot withstand overload, and it is not allowed to measure more than the maximum value of the instrument range.
(2) Qualified use. Check the validity period of the thermometer certificate before use, and use a qualified thermometer.
(3) Vertical installation. The thermometer should be installed vertically on the mounting plate without vibration; during installation, the capillary should be straightened and fixed with a tie, and the distance should not exceed 300mm.
(4) It cannot be bent or folded during installation. The capillary tube of the pressure thermometer cannot be squeezed, and care should be taken to keep the capillary tube unobstructed and not folded or bent. When the capillary is installed, the bending radius should not be less than 50 ram, as shown in Figure 2-23, bend the circle so that the pressure generated in the temperature bubble can be quickly transferred to the spring pressure gauge to indicate the temperature.
(5) Warm bubble insertion. When installing (installation nut M33×2 or M27×2), insert all the warm bubbles into the measured medium, try to reach the maximum depth, and avoid errors caused by insufficient insertion depth.
(6) Liquid level measurement. The spring pressure gauge and the temperature bubble should be kept on the same level to reduce the additional error caused by the pressure change caused by the action of the static pressure column.
(7) Measure the reading. When the pointer of the thermometer is stable, the eye is perpendicular to the glass surface of the pressure thermometer to read, and the read data is the measured temperature.
