At industrial and manufacturing enterprises, various heat installations operating under pressure are used for heat supply: water heating and steam boilers, gas pipelines and steam pipelines, compressor units.
What is the minimum water level in the boiler?
Steam boilers are universal heat carriers for water and steam heat supply systems. They find application not only in ordinary production boiler houses, but also in mixed enterprises where steam and hot water are needed.
Water heating boilers are one of the simplest schemes for the release of heat in the form of hot water. The main difference between such boilers and steam boilers is that no vapor droplets form inside the pipes. In steam boilers, such vaporization contributes to salinization of the liquid and overheating of the metal.
During the operation of the boilers, the following violations are possible: loss of water, increase in the level above the limit, water entering the fuel cells, sudden temperature changes, water boiling and its discharge into the superheater. As a result of these violations, a hydraulic shock occurs and, as a result, an emergency in the heat supply system.
The value of the average level in the boiler is set by the manufacturer and is adjusted based on starting tests. High-quality regulation of the water level in the boiler unit ensures its stable operation. Therefore, for precise regulation strict requirements are put forward.
Typically, the control of the power system is determined by the steam capacity of the boilers, which is carried out by special regulators. Regulators are designed to influence the degree of opening of the power valve. They are single-pulse, double-pulse and three-pulse. Depending on the flow of steam and feed water, the regulators control changes in the power supply system. As an indication device can serve as a sight glass placed on the regulator.
The level in the boiler drum indicates the balance between the steam flow rate and the feed water flow rate. Identification of deviations from the average value indicates an imbalance in the nutritional system. Deviation is also possible due to changes in steam pressure in the boiler drum.
Maintaining an average level should be stable even with changes in steam productivity.
The deviation of the level from the average value by 150 mm from the highest heated point of the drum and the connection of the downpipes is considered an acceptable minimum level.
Reference! If the water level drops below the visible part of the sight glass, this change is called an “overlook”. With an increase, a “replenishment” of the level occurs. The distance between these limit values can be 400 mm.
If the water will be less than the minimum
If there is a decrease in the level below the permissible limit, then the termination of treatment is possible. Due to a stop in the circulation system, a sharp jump in temperature occurs. Such omission can lead to disruption of the entire power system. The vapor-forming pipes are exposed, then their cooling occurs, the strength in the connecting places is violated, which subsequently leads to the burning of the entire system.
The main causes of water loss:
- damage or shutdown of automatic power;
- damage to water indicating devices;
- water shortage in the deaerator;
- violations in the work of staff;
- malfunction of drain elements.
If the level drops below the minimum, the operator, in accordance with the "Rules for the Construction and Safe Operation of Steam and Water Boilers", must emergency stop the boiler unit. This is done by stopping the transfer of fuel and associated components. Liquid discharge is possible as a result of cooling the temperature not higher than 70 degrees Celsius.
The importance of maintaining the water level in the boiler
The need to maintain the liquid level in the drum makes it possible to provide constant power to the boiler. An increase in the upper limit level causes temperature fluctuations inside the device and leads to boiling. With intense vaporization, a sharp release of salts occurs, which leads to a skid of the superheater, the undercarriage of the turbine and, as a result, a decrease in its efficiency and throughput.
Also, boiling is possible due to the low quality of the liquid, a large amount of impurities and oil products. In this case, increased scale formation and subsequently overheating of the pipes occurs. To eliminate the cause of boiling, it is necessary to reduce steam production, fuel consumption, close the main stop valve and carry out continuous or periodic purging. Purging removes scale converted to sludge.
Reference! According to the rules of the State Supervision, it is forbidden to operate the boiler even with one faulty element. Faulty valve in the regulator, pressure gauge, metal corrosion in high-voltage elements, lack of a spare feed pump, faulty filters - all this can lead to explosion of boilers or fire in the boiler room.
All of the indicated causes of malfunctions in the boiler power system are comprehensive. For the boiler to operate properly, it is necessary to pay attention to the manufacturers of boiler plants, control the parameters of the liquid, avoid measurement errors, and take timely measures to eliminate malfunctions.
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