Multi-stage high-temperature boiler circulating pumps actually belong to multi-stage pumps. The working principle is equivalent to assembling several impellers on a pump shaft and working in series. The number of impellers on the pump shaft also means that it belongs to several stages. Stage centrifugal pump, for example, the head of an impeller is 10 meters, then adding 5 impellers on the pump shaft is equivalent to the head can reach 50 meters at this time. During operation, water is sucked in from the pump inlet and then pressed in by the impellers To the next impeller, the pressure will double every time it passes through the impeller.
The function of the high temperature and high pressure boiler circulating water pump is to increase the pressure of the heated and deoxygenated water and send it to the boiler. In order to ensure the safe operation of the boiler, the boiler must be supplied with water without interruption. The feedwater pump set of this unit is composed of three 50% capacity electric pumps, two of which are in operation and one is in standby. All of them are variable speed feedwater pumps with hydraulic coupling. Compared with fixed speed, variable speed has the following advantages: it saves plant electricity, simplifies the water supply operation console, easy to realize automatic adjustment of water supply, can meet the needs of unit sliding pressure operation and peak regulation, improve the safety and reliability of the unit, and facilitate start-up.
The leaking mechanical seal of the circulating pump of the multi-stage high temperature and high pressure boiler is the main cause of the leakage of the water pump. However, the mechanical seal itself is a demanding precision component, which has high requirements on design, machining, and assembly quality. When using mechanical seals, the various factors of using mechanical seals should be analyzed to make the mechanical seals suitable for various pump technical requirements and use medium requirements and have sufficient lubrication conditions, so as to ensure long-term and reliable operation of the seal.
Water leakage in the outlet section of multi-stage high-temperature boiler circulating pumps is common. If it is not shell leakage, the mechanical seal of the pump is broken and the water tightness cannot be guaranteed. In this case, the mechanical seal can be repaired or worsened. Most of the reasons are When the mechanical seal is broken, it causes the water pump to leak. In fact, the mechanical seal is not so easy to break, mostly because there is sand in the water, which is easy to damage. . Solution:
1. The water pipe connection is leaking, and the chance of new installation is small. Measures: reinstall after disassembly. 2. The water pump leaks when pumping. Generally, the water seal leaks. Measures: remove the water pump and replace the water seal. 3. The water pump is leaking for a long time. It may be that the upper water pipe is not installed with a check valve on the outlet side of the water pump. Measures: Install a check valve.
Water leakage at the shaft head of the circulating pump of the multi-stage high temperature boiler:
1. Replacing the packing. As mentioned above, the leakage of the shaft head is mainly caused by the wear of the shaft sleeve. The replacement of the packing can not fundamentally solve the water leakage failure. Its function is only to fill and compact the worn shaft sleeve with filler, which can only temporarily solve the problem of water leakage. 2. Using wear-resistant bushings, disassemble the replaced pumps and replace them with bushings of wear-resistant materials. However, the middle bushing has a long processing cycle and is expensive. At the moment when the company is vigorously reducing costs, this solution Not the first choice.
How to prevent the water leakage of the circulating pump of the multi-stage high temperature boiler:
1. Clean the water pipe before the test machine and check whether the water quality is suitable for the operation of the pump. 2. Before the test machine, be sure to open the exhaust hole to remove the air in the pump. Finally, there is a coup: adding an O-ring when installing the mechanical seal can also increase the life of the mechanical seal.
