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How To Use Stainless Steel Pressure Thermometer
Dec 25, 2018

How to use stainless steel pressure thermometer

Today, I would like to share with you the use of stainless steel pressure thermometers. Generally, we have two steps when using stainless steel pressure thermometers. Which two steps are there? Let's take a look.

How to use stainless steel pressure thermometer不锈钢是压力温度计

1. First of all, check the appearance

Protective glass or other transparent materials for stainless steel pressure thermometers shall be transparent and shall not have defects or damages that impede correct reading; the components shall be assembled firmly, shall not be loose, shall not be rusted, and shall not cause significant corrosion and peeling of the anti-corrosion layer. The scales, numbers and other markings on the thermometer dial should be complete, clear and accurate. The electrical contact thermometer shall also indicate the rated power of the contact, the high voltage of the contact, the maximum operating current of the AC or DC on the dial or the outer casing, and the grounding terminal shall have a grounding mark.

2. Second is the measurement method of stainless steel pressure thermometer

(1) Optional instrumentation. The stainless steel pressure thermometer is selected according to the temperature value of the measured process parameters. Selection principle: The working temperature of the thermometer should be 1/2 to 3/4 of the measurement range. The temperature bubble of the pressure thermometer cannot withstand overload, and the maximum value of the measurement is not allowed to exceed the meter range.

(2) Qualified use. The validity period of the certificate of the thermometer should be checked before use, and a qualified thermometer should be used.

(3) Vertical installation. The thermometer should be mounted vertically on a mounting plate that is free of vibrations; when installed, the capillaries should be straightened and secured with a head at intervals no greater than 300 mm.

(4) It cannot be bent and folded during installation. The capillary of the pressure thermometer cannot withstand the squeezing, and care should be taken to keep the capillary clear and not fold and bend. When the capillary is installed, the bending radius must not be less than 50 ram, as shown in Figure 2-23, to bend the circle so that the pressure generated in the warm bubble is quickly transmitted to the spring pressure gauge to indicate the temperature.

(5) Warm bubble insertion. When installing (mounting nut M33×2 or M27×2), insert all the warm bulb into the measured medium and reach the maximum depth as much as possible to avoid errors due to insufficient insertion depth.

(6) Level measurement. The spring gauge and the warm bulb should be kept at the same level to reduce the additional error caused by the pressure change caused by the hydrostatic column.

(7) Measurement readings. When the thermometer pointer is stabilized, the eye is perpendicular to the surface of the pressure thermometer glass, and the read data is the measured temperature value.

How to use stainless steel pressure thermometer

Construction and working principle of stainless steel pressure thermometer

The stainless steel pressure thermometer is a thermometer for temperature measurement based on the relationship between the saturated vapor pressure of the evaporating liquid in the closed temperature measuring system and the temperature.

The stainless steel pressure thermometer and the serialized temperature measuring instrument developed thereby overcome the shortcomings of single instrument performance, poor reliability and large temperature accumulation, and reduce the volume of the temperature measuring component to 1/30 or 1/60 of the original. The sensor thermal resistance is creatively installed in the temperature measuring element to realize the mechatronics temperature measuring function. A multi-function series temperature meter with a liquid pressure type thermometer as a basic temperature measuring instrument, such as remote transmission, anti-vibration, anti-corrosion, electric contact, temperature signal transmission, etc., is formed. Divided into two series, normal type and explosion-proof type.

Main structure of stainless steel pressure thermometer

1. Warm pack: It is a component that directly contacts the measured medium to sense the temperature change, so it is required to have high strength, small expansion coefficient, high thermal conductivity and corrosion resistance. The warm pack can be made of copper alloy, steel or stainless steel depending on the working substance and the medium to be tested.

2. Capillary: It is a seamless round tube that is cold drawn from copper or steel to transmit pressure changes. The outer diameter is 1.5~5mm, and the inner diameter is 0.15~0.5mm. The thinner the diameter, the longer the length, the more severe the hysteresis of the transmitted pressure. In other words, the slower the response of the thermometer to the measured temperature. However, at the same length, the finer the capillary, the higher the accuracy of the meter. The capillary is easily broken and broken, so it must be protected. A metal hose can be used as a protective sleeve for a capillary that is not often bent.

3. Spring tube: It is an elastic element for general pressure gauges.

How to use stainless steel pressure thermometer

How does a stainless steel pressure thermometer work?

The principle of a stainless steel pressure thermometer is based on the relationship between the saturated vapor pressure of the evaporating liquid in the closed temperature measurement system and the temperature. When the temperature sensing changes the temperature, the saturated steam in the closed system generates a corresponding pressure, causing the curvature of the elastic element to change, causing the displacement of the free end, and then the displacement is changed to the indicated value by the gear amplifying mechanism. The thermometer has a temperature. With small volume, fast response, high sensitivity and intuitive reading, it has almost all the advantages of glass rod thermometer, bimetal thermometer and gas pressure thermometer. It can be made into shockproof and anti-corrosion type, and can realize remote contact. Signal, RTD signal, 0-10mA or 4-20mA signal. It is a mechanical temperature measuring instrument with the widest range and the most comprehensive performance.