I. Introduction Our company's new 40,000-ton/year methane chloride plant has been officially put into operation. During the equipment selection phase of the project, after extensive research and adhering to the concept of innovation, we selected 27 new Hymettek magnetic drive pumps based on the production process principles and the characteristics of the transported materials. Hymettek magnetic drive pumps are manufactured by Dalian Hymettek Sealing Pump Co., Ltd. These pumps feature an advanced design, are seal-free, and as a leak-free, maintenance-free, and highly reliable centrifugal pump, they are safe, efficient, and energy-saving. They are suitable for transporting corrosive, toxic, flammable, explosive, expensive, or easily vaporized liquids. In addition, Hymettek magnetic drive pumps are also suitable for transporting high-temperature, low-temperature fluids, and liquids under vacuum conditions. Due to their completely leak-free advantage, they successfully solve the problems of running, leaking, dripping, and seeping in fluid transportation, and have become an irreplaceable product in environmental protection engineering, widely used in petroleum, chemical, refrigeration, air conditioning, aerospace, and other fields. Compared with traditional sealed pumps, Hymettek magnetic drive pumps have advantages such as less maintenance workload, no need for external lubrication, no leakage, and low vibration and noise. However, due to its own characteristics, it differs from traditional centrifugal pumps in many aspects. Therefore, some measures and approaches need to be taken in terms of process, installation, and operation to ensure its reliable and stable operation.　Features of the Hemetek Magnetic Drive Pump: 1. Structure: The Hemetek magnetic drive pump is a horizontal, leak-free centrifugal pump with axial suction and radial discharge. The pump shaft is driven by a magnetic coupling, eliminating the need for a rotating shaft seal and achieving "zero leakage." 2. Bearings: The drive shaft of the Hemetek magnetic drive pump is supported by rolling bearings, which are lubricated by their own grease. The pump shaft is also supported by hydraulic sliding bearings. 3. Magnetic Coupling: The magnetic blocks in the Hemetek magnetic drive pump are made of high-quality rare-earth permanent magnet material with a maximum irreversible temperature of 350-400℃, ensuring reliable performance of the magnetic coupling. During normal operation, the magnetic coupling operates synchronously with the three-phase asynchronous motor, providing stable performance. Furthermore, the permanent magnets have high stability, preventing adverse effects during rotor assembly and disassembly or when the pump operates at maximum torque. 4. Lubrication of Sliding Bearings and Cooling of Magnetic Coupling: The pumped medium provides lubrication and cooling, eliminating the need for external lubricating oil and cooling water systems. 5. Axial Force Balance: During operation, the axial force of the Hemetek magnetic pump is automatically balanced hydraulically, and the drive disc only bears instantaneous axial thrust during startup and shutdown. [b]III. Analysis of Common Faults in Hemetek Magnetic Pumps[/b] 1. Problems caused by large fluctuations in pump operating conditions: The axial force of the Hemetek magnetic pump is automatically balanced by hydraulic balancing. In actual operation, if the operating parameters (inlet pressure, outlet pressure) fluctuate greatly, it is easy to disrupt the hydraulic balance of the Hemetek magnetic pump, causing the sliding bearing to bear large radial and axial forces, leading to bearing damage. 2. Problems caused by pump cavitation: The main causes of pump cavitation include high inlet pipe resistance, a large amount of gas phase in the conveyed medium, insufficient priming, and insufficient pump inlet head. Cavitation is the most harmful to the pump. When cavitation occurs, the pump vibrates violently, and the hydraulic balance is severely disrupted, leading to damage to the pump bearings, rotor, or impeller. This is a common cause of Hemetek magnetic pump failures. 3. No medium or low flow rate of the medium: causes dry friction of the bearing and burns the bearing. The Hemetek magnetic pump is lubricated and cooled by the medium it is conveying. Without opening the inlet or outlet valve, the sliding bearing will be damaged due to the lack of lubrication and cooling by the medium. 4. Damage to the isolation sleeve: The magnetic coupling of the Hemetek magnetic pump is cooled by the medium it is conveying. If there are hard particles in the medium, it is easy to scratch or puncture the isolation sleeve. Sometimes, improper maintenance may also cause damage to the isolation sleeve. IV. Methods and approaches to improve the reliability of Hemetek magnetic pump operation 1. Equipment and pipeline installation requirements: (1) The pump inlet and outlet pipelines should be supported to prevent additional loads from being transmitted to the pump. The pump should not be used as a stress point in the pipeline. The pipeline system should be guaranteed to have compensation measures for thermal expansion. (2) When the positive suction head is low, the inlet pipeline should be as short as possible to prevent cavitation. The inlet pipe should be of appropriate size to ensure that the fluid velocity does not exceed 3 m/s; when conveying easily vaporized fluids or liquefied gases, the velocity should not exceed 3 m/s; when conveying easily vaporized fluids or liquefied gases, the velocity should not exceed 1 m/s. (3) A regulating valve should be installed on the outlet pipe to regulate the pump flow rate and head. When using a long outlet pipe or two pumps in parallel, it is recommended to install an additional one-way check valve. (4) The entire piping system and auxiliary pipes should be carefully cleaned to prevent iron filings, welding slag or other foreign objects from entering the Hemetek magnetic pump. For newly built piping systems, the inlet pipe should be equipped with a filter. (5) The piping design should take into account the pump's exhaust. (6) To achieve continuous operation of the pump, it is recommended to install a return pipe with a minimum flow orifice plate to ensure that the sliding bearings have sufficient lubrication and cooling during continuous operation. As shown in Figure 1, the return pipe should be led out before the outlet valve or one-way check valve and return to the storage tank through the minimum flow orifice plate. This installation enables automatic venting of the pump. (7) The Hemetek magnetic pump must operate within the specified range. To control the maximum flow rate, it is recommended to install a suitable maximum flow orifice plate on the outlet pipe. (As shown in Figure 1) 2. Process monitoring: Due to the design characteristics of the Hemetek magnetic pump, it generally does not require maintenance. However, to ensure its normal operation and safe operation, a process monitoring device should be used and strictly managed. (1) Inlet tank level protection control is necessary. The inlet tank should be equipped with a level transmitter or level switch. When the inlet tank level drops to a certain level, the pump should be automatically stopped to protect the pump. (2) The pump body should be equipped with a temperature sensor to monitor the temperature of the magnetic stator and pump bearings to protect the bearings and magnetic stator. (3) The pump outlet should be equipped with a level regulating valve to adjust the discharge rate of the conveying medium according to the inlet tank level. (4) A differential pressure sensor and switch should be installed to measure the differential pressure between the pump outlet and inlet. When the differential pressure is lower than the set value, the pump should be automatically stopped to protect the pump. (5) The pump has minimal vibration. Significant vibration and noise indicate a malfunction. (6) To ensure normal operation, the pump should operate within the flow rate and head range shown in Figure 2. The minimum and maximum operating flow rates and heads are indicated on the performance curves. (7) To avoid cavitation, the Hymetek magnetic pump requires a minimum suction head (emin) when conveying easily vaporized fluids. This head is calculated using the following formula: (emin) (m) = NPSH pump (m) + inlet pipe friction loss (m) + safety margin (m). The safety margin is usually 0.5m. V. Operating Points: (1) Priming and Exhausting: To ensure the normal operation of the Hymetek magnetic pump, it is essential to fully prim and exhaust the pump. Fully open the valves in the pump inlet, return, and outlet pipes to achieve automatic exhaust of the Hymetek magnetic pump. When conveying liquefied gas or easily vaporized liquids, exhaust the pump several times until the pump is fully filled with liquid. If conveying cryogenic liquids, the pump should be started only after the flow-through components have cooled to the temperature of the liquid. This ensures that the fluid has reached all parts of the pump. (2) Starting procedure: The model of the magnetic coupling is selected according to the drive motor to achieve normal operation. However, if it is started under unsuitable conditions (such as excessive motor power, excessively large opening of the outlet valve, or high voltage), the maximum torque of the magnetic coupling will be exceeded, making the pump unable to operate normally. Therefore, it is important to start it correctly. a. Fully open the valve in the inlet pipe; b. Close the valve in the outlet pipe; c. Start the motor; d. Slowly open the valve in the outlet pipe; e. Adjust the outlet valve until the normal operating pressure is reached; f. To ensure normal operation of the pump, it should be operated within its allowable range.　**VI. Operation and Maintenance Precautions:** 1. The Hemetek magnetic pump must never be operated under dry friction conditions or with the outlet pipeline valve closed, otherwise it will cause damage to the sliding bearing! 2. It must work synchronously with the motor. If the pump fails (very low head), it indicates that the maximum torque of the magnetic coupling has been exceeded. Prolonged operation under unsuitable conditions should be avoided. 3. Under normal operating conditions, vibration, excessive noise, and power increase indicate bearing wear (insufficient lubrication), and should be checked immediately. 4. The rolling bearings of the Hemetek magnetic pump are deep groove ball bearings, permanently lubricated by their own grease, but should still be checked and replaced regularly. 5. Failure of the magnetic coupling does not necessarily mean damage to the permanent magnet. However, prolonged operation in a failed state, due to its low speed and poor lubrication of the sliding bearing, will lead to damage to the sliding bearing. 6. The rotor assembly and drive assembly have high magnetism. When assembling and disassembling the Hemetek magnetic pump, the magnetic field range should be considered, as it may have a certain impact on electrical and electronic devices. Maintain a certain distance! 7. If the liquid being transported crystallizes or solidifies during prolonged storage, a suitable liquid should be used to...