The classification of pressure gauges in electric heating oil heater, the selection of pressure gauges and the installation and daily maintenance of pressure gauges.
1 Classification of pressure gauges
Pressure gauges can be roughly divided into four categories according to their conversion principles:
The first type is a liquid column manometer:
According to the principle of hydrostatics, the measured pressure is expressed by the height of the liquid column. The structure form is also different, so it can be divided into U-shaped tube pressure gauge, single tube pressure gauge and so on. This kind of manometer has a simple structure and is very convenient to use, but its accuracy will be greatly affected by factors such as the action of capillary tubes, density and parallax. Because the measurement range is relatively narrow, it is generally used to measure low pressure, pressure difference or vacuum degree.
The second type is an elastic manometer:
It is converted to the measured pressure by the displacement of the deformation of the elastic element, such as the spring tube manometer and the mode manometer and the spring tube manometer.
The third type is an electrical pressure gauge:
It is the instrument that converts the measured pressure into the electrical quantity of mechanical and electrical components (such as voltage, current, frequency, etc.) for measurement, such as various pressure transmitters and pressure sensors.
The fourth type is a piston pressure gauge:
It is measured by using the principle of hydraulic press liquid transfer pressure, and comparing the mass of balanced silicon code added to the piston with the measured pressure. It has high measurement accuracy, as small as 0.05 intestinal ~ 0? Error of 2%. But the price is more expensive, the structure is more complex. To check other types of pressure timepieces are available as standard pressure measuring instruments.
Hot oil system is used in the general pressure gauge, it has a sensitive element a bourdon tube, the table inside the movement of the conversion mechanism, when the pressure is generated, the Bourdon tube will be elastic deformation, the movement of the mechanism to convert the elastic deformation into rotating motion, and the pointer connected with the mechanism will be deflated to show the pressure.
Therefore, the pressure gauge used in the thermal oil furnace system is the second elastic pressure gauge.
2 Selection of pressure gauge
When the pressure of the boiler is less than 2.5 mi, the accuracy of the pressure gauge is not less than 2.5 level: the working pressure of the boiler is more than 2. SMPa, the accuracy of the pressure gauge is not less than 1.5 level; For boilers with working pressure greater than 14MPa, the accuracy of the pressure gauge should be level 1. The design working pressure of the hot oil system is 0.7MPa, so the accuracy of the pressure gauge used should not be depressed 2.5 grade 2 Because the range of the pressure gauge should be 1.5 to 3 times the maximum pressure of the boiler, we take the middle value 2 times. So for the pressure gauge the amount is 700.
The pressure gauge is fixed to the boiler housing, so that it is not only easy to observe, but also easy to perform regular flushing operations and change the position of the pressure gauge.
3. Installation and daily maintenance of pressure gauge of thermal oil furnace
(l) The ambient temperature of the pressure gauge is 40 to 70 ° C, and the relative humidity is not more than 80%. If the pressure gauge deviates from the normal use temperature, the temperature additional error must be included.
(2) The pressure gauge must be vertical, and strive to maintain the same level with the measurement point, such as the difference is too high into the additional error caused by the liquid column, the measurement of gas can not be considered. When installing, block the explosion-proof opening at the back of the case so as not to affect the explosion-proof performance.
(3) The measuring range of the normal use of the pressure gauge: not more than 3/4 of the measuring upper limit under static pressure, and not more than 2/3 of the measuring upper limit under fluctuation. In the above two pressure cases, the minimum measurement of the large pressure gauge should not be lower than 1/3 of the lower limit, and the vacuum part is all used when measuring the vacuum.
(4) When using, if the pressure gauge pointer fails or the internal parts are loose and cannot work normally, it should be repaired, or contact the manufacturer for maintenance.
(5) The instrument should avoid vibration and collision to avoid damage.
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Post time: Jun-27-2024
