When the traditional DG type segmented multistage centrifugal pump is in operation, most of the axial force is balanced by the balance disc device. The disadvantage of this method of balancing the axial force is that in the later stage of the pump, as the wear intensifies, the impeller and the guide vane sleeve, The gap between the seal rings gradually increases, and the amount of liquid leakage at the seal ring increases accordingly, which will increase the axial force greatly. The axial force that can be balanced by the balance plate cannot be balanced, and the wear of the balance plate and the balance ring is increased, which seriously affects the safe operation of the unit.

1. The phenomenon that the boiler feed water pump reverses during operation (1) The flow at the inlet of the feed water pump is zero. (2) The speed of the feed water pump rises sharply when the opening of the scoop tube remains unchanged. (3) The feedwater flow rate drops significantly, which often triggers the action of the low water level protection of the steam drum. (4) The temperature of the bearing of the feedwater pump rises rapidly. (5) Fusible plugs on the spot or already melted, spray a lot of oil outward.     　　 2. Reasons for the reversal of the boiler feed water pump during operation The reversal of the feedwater pump occurs during the start and stop (including tripping) of the unit to switch the water supply mode. When the outlet pressure of the running steam-driven feedwater pump is higher than the outlet pressure of the feedwater pump, the outlet door of the feedwater pump is in the open state. The return valve jams and is not closed tightly, which causes the electric feed water pump to reverse. 3. How to deal with the reversal of the boiler feed water pump during operation (1) When confirming that the feed water pump is reversed, immediately close the electric door of the electric feed water pump outlet, and start the auxiliary oil pump of the electric feed water pump at the same time. (2) Adjust the feedwater flow during the time when the electric valve at the outlet of the feedwater pump is closed, maintain the water level of the steam drum, and pay attention to the running speed of the steam-driven feedwater pump and the opening of the steam inlet valve not exceeding the limit. The boiler can cooperate to reduce the load. (3) Adjust the opening of the spoon tube according to the specific situation. The scoop tube opening is large, the reverse torque is large, and the axial thrust changes direction easily to damage the equipment; the scoop tube opening is small, the reverse resistance is small, and the flying speed is large. (4) It is forbidden to shut down the feedwater pump motor, except for protection actions. Because after clicking Stop, the motor reverses along with the feedwater pump, and the oil pump driven by the pump wheel reverses. There is a check valve at the outlet of the working oil pump, so that the feedwater pump cuts off the oil and burns the tiles. (5) Inspect the feedwater pump on the spot, disassemble it for inspection if necessary, overhaul the check valve of the feedwater pump, and put it into standby after the test action is flexible and reliable. 4. Prevention of reversal during operation of boiler feed water pump (1) When trying to start the feedwater pump, check whether the recirculation door is open, and the feedwater pump should be run without load with the outlet door closed. (2) Before stopping the feed water pump, close the electric outlet door. (3) When the feedwater pump is incorporated into the system, increase the speed of the electric feedwater pump to bring the feedwater pump close to the outlet pressure of the steam-driven feedwater pump, and then open the pump outlet door. (4) When increasing the speed of the electric pump when the feedwater pump is connected, it should be noted that the inlet pressure and speed of the feedwater pump rise steadily without large fluctuations, the outlet flow does not fluctuate significantly, and the feedwater flow does not suddenly decrease. (5) When the feedwater pump is in standby to open the outlet door, there should be inspectors on standby at the outlet door control switch and the feedwater pump site, pay attention to whether the rotor is rotating, and the CRT monitors whether the speed and outlet pressure of the electric feedwater pump change. Invert the signal. If the electric feed water pump is found to be reversed, the outlet door should be closed immediately.

The core product of the mine drainage system, the mine multi-stage pump, as one of the important guarantees for maintaining mine safety, shoulders a huge responsibility. Therefore, buying a reliable mine multi-stage pump can more effectively guarantee mine production. Safety.     实地考察   So the question is, how can I buy a high-quality multi-stage pump for mining? As long as you follow the following five steps, you can see all the routines and really buy quality products. In the first step, you have to find out the real working conditions of the mine, how big the flow is, how high the lift is, so that you can do better matching. Bad matching is not only inefficient, but also the service life will be shortened. The choice of mining multi-stage pump is not the bigger the better, nor the smaller the better, but according to the actual situation to make dynamic matching, choose the most suitable for your own mining multi-stage pump. The second step is to find mining multi-stage pump manufacturers through various channels. You can start with friends, colleagues, dealers, online, etc., and find some more professional mining multi-stage pump manufacturers. The third step is to make a comprehensive comparison and verification of the credit status of the water pump manufacturers, and select two or three with stronger strength.     Field trips   The fourth step is to conduct on-site inspections of the selected manufacturers (go to their production plants instead of distribution outlets). This step is particularly critical. Because the previous information, credit and other content are all words of one family, there are different degrees of exaggeration, and further field inspections and verifications are needed to see their scale, production equipment, product warehouse inventory, R&D level, production management level, and product quality inspection level. And so on, compare the credit information provided before to ensure that there are no errors and the information is true and valid. After this step, a comprehensive ranking is performed on the selected manufacturers. The fifth step is to test the product application cases on the spot, and select the product use cases advertised by the manufacturer for on-site inspections to determine whether it really exists. In addition, you can learn about the product usage, failure rate, after-sales guarantee capability and other comprehensive usage information from the side . At the same time, after investigating the case, you can also understand the use of others, learn from each other, and improve your own use and management level.     Field trips   If you strictly follow the above five steps, then congratulations, the mining multi-stage pump you purchased must be a reliable quality product. For excessive publicity on the Internet, please be sure to polish it up. For both eyes, it is best to conduct a field survey. After all, many people are good at creating momentum and PS technology is very powerful. After the on-site inspection, these routines will have nowhere to hide, which will also minimize the hidden dangers of mine drainage systems and create a safer and more reliable production environment.