Boilers are widely used in the industrial sector, especially in the refining industry. Each large refinery has more than a dozen medium-pressure boilers. The boiler is a high-temperature high-force container, which is a relatively dangerous device. Once the high temperature and high force steam leaks, it is easy to cause personal injury. The level gauge used on the boiler steam drum is a key equipment of the boiler. The liquid level in the steam drum is used to observe it. Some people call it the "eye" of the boiler. If there is a problem with the "eyes", the boiler equipment and the steam supply system is in a dangerous state, so how to choose the boiler drum level gauge is one of the most important problems for each boiler supervisor.
2. About quartz tube level gauge
Inspection before installation
Quartz tube Type liquid level meter is the main components of quartz tube, quartz material, has excellent high temperature performance, its thermal expansion coefficient is very small, the average coefficient of thermal expansion between 0-1000 ℃ α=5.4x10-7, only 1 of ordinary glass 20, the hardness of the Mohs hardness of about 6.7, much than the ordinary glass hardness of 5.5. Quartz tube hard and brittle, in the course of the rough loading and unloading is easy to cause quartz tube damage, so before installation in addition to regular inspection should carefully check whether the quartz tube is complete, the installation process should also be lightly handled.
Check the upper and lower flanges on the drum for the level gauge to be mounted on a vertical surface, center distance and observation surface is correct, if there is no problem, you can directly install, otherwise, the table body and valve or tee connection between the nut to loosen, adjust the center distance and observation surface of the liquid level gauge, and then the liquid level gauge flange and equipment flange fixed well, It is better to tighten the loosened nut. If the flange on the drum is not on a vertical surface, the difference is relatively large, you should first handle the flange, and then install. The forced installation will distort the meter body and eventually cause the quartz tube to break. Where conditions are best installed two globe valve, liquid level meter after installation does not need to keep warm, so that the level meter can operate at relatively low temperature, to reduce cavitation, prolong the life of the liquid level meter.
Put into use
When commissioning, it is best to open the water valve first to allow a small amount of water to enter the watch body for warming, and then open the steam valve after a few minutes.
During the operation, not only the liquid level but also the cavitation of the quartz tube should be observed. The cavitation of the quartz tube occurs in the upper part of the liquid surface. The top of the quartz tube is the most serious. The lower aperture is twice as large, and the upper tube wall of the quartz tube is already thin. For safety reasons, the quartz tube should be replaced in time.
The liquid level gauge is a connected body. The condensed water on the surface of the watch continuously flows down the inner wall of the smooth quartz tube and flows back to the steam drum through the liquid pipe. The most important thing is that the liquid level in the steam drum constantly fluctuates, prompting the table. The water in the body is constantly exchanged with the water in the steam drum, which means that the water quality in the watch body is basically the same as the water quality in the steam drum, even if there is a small amount of smudging, it will sink below the liquid pipe, and Does not affect the liquid level observation, so there is no need to rigidly stipulate that each class must flush the level gauge once in the boiler operation regulations, but should determine whether to discharge according to the actual contamination situation of the level gauge.
3. About magnetic liquid level gauge
Inspection before installation
In addition to the routine inspection, the magnetic flip level gauge should check whether the dial indicator is detached and check whether the pressure and density meet the requirements.
During installation, there should be no magnetic or magnetic material within 50mm of the magnetic flip level gauge, otherwise it will affect the normal operation of the float.
Put into use
Open the steam valve first, then open the water valve so that the water level will rise from zero to the actual height.
Since the magnetic level gauge measures the water level indirectly and is of an all-metal structure, the sewage discharge does not cause any damage to the liquid level gauge. Therefore, the liquid level gauge can use the sewage discharge mode of the glass plate level gauge to accurately observe the operator. It is very helpful to determine the water level and the operation of the level gauge.