Stator Cooling Water Pump DFB80-50-220: Complete Guide to Verifying the Mechanical Seal Before Starting

In a thermal power generator set, the stator cooling water pump is a key device to ensure the stable operation of the generator. Its core component, the mechanical seal, is directly related to the sealing performance and service life of the water pump. Taking the DFB80-50-220 stator cooling water pump as an example, the reliability of the mechanical seal not only affects the circulation efficiency of the cooling water, but also determines the safety of the entire unit. However, many users tend to ignore the verification of the mechanical seal before starting the pump, resulting in leakage, abnormal vibration and other problems after the equipment is started. This article will analyze how to scientifically verify the mechanical seal status of the stator cooling water pump DFB80-50-220 from the perspective of practical operation to help users avoid potential risks.

1. Mechanical seal: the “invisible guardian” of the stator cooling water pump

The mechanical seal is the core sealing device of the stator cooling water pump. Its function is to prevent the cooling water from leaking from the inside of the pump body to the external environment through the precise cooperation of the dynamic ring and the static ring. The mechanical seal of the DFB80-50-220 water pump is usually composed of a spring, a rotating ring, a stationary ring and a sealing ring. The materials are mostly high-temperature resistant and corrosion-resistant metal and non-metal composite materials. During operation, the mechanical seal needs to withstand multiple challenges of high pressure, high-speed rotation and temperature changes. If the sealing condition is not good, cooling water leakage will not only lead to a decrease in the efficiency of the water pump, but may also cause motor overheating or even shutdown accidents. Therefore, mechanical seal verification before starting the pump is crucial.

2. The “three-step method” to verify the status of the mechanical seal

Step 1: Cleaning and inspection before installation

During the installation stage of the mechanical seal of the stator cooling water pump DFB80-50-220, cleanliness is the first step to determine the sealing performance. According to industry specifications, all sealing components (including dynamic rings, static rings, sleeves and glands) must be thoroughly cleaned to remove surface oil, dust and metal debris. For example, the sealing end faces of the dynamic ring and the static ring need to be wiped with lint-free cloth dipped in alcohol to ensure that there are no scratches or dents. If the end face is found to be worn or deformed, it should be replaced with a new part immediately. In addition, a proper amount of lubricating oil should be applied to the joint between the sleeve and the shaft to avoid damage to the sealing surface due to dry friction at the moment of pump startup.

Step 2: Alignment and tightening during assembly

The assembly accuracy of the mechanical seal directly affects its operating stability. The mechanical seal of the DFB80-50-220 water pump is usually installed with a gland type, and it is necessary to ensure that the coaxiality error between the dynamic ring and the shaft does not exceed 0.05mm. During assembly, the gland bolts need to be tightened evenly in batches to avoid deformation of the sealing element due to excessive force. For example, the bolts can be tightened step by step in the order of “diagonal cross”, and the shaft can be gently rotated by hand to confirm that the mechanical seal is not stuck. In addition, the compression of the sealing ring needs to be strictly controlled. Excessive compression will accelerate the aging of the sealing material, while too little compression may cause the seal to fail.

Step 3: Dynamic test before starting the pump

After completing the installation, the sealing performance of the mechanical seal needs to be verified through static and dynamic tests. The static test can be performed by filling the pump cavity with cooling water and pressurizing it to 1.5 times the working pressure to observe whether there is leakage at the seal. If there is no abnormality, perform a dynamic test: start the water pump and run it for about 5 minutes, while monitoring the leakage, vibration value and temperature change at the seal. Under normal circumstances, the mechanical seal leakage of the stator cooling water pump should be less than 5 drops/minute, the vibration value should be less than 0.5mm/s, and the sealing surface temperature should not exceed 80℃. If an abnormality is found, it is necessary to stop the machine immediately for investigation, such as checking whether the sealing surface is worn due to impurities intrusion, or whether the spring pressure is reduced due to fatigue.

3. Common problems and coping strategies

In actual operation, the mechanical seal problems of the stator cooling water pump DFB80-50-220 often come from the following reasons:

Sealing surface wear or contamination: After long-term operation, the sealing surface may form tiny scratches due to particle intrusion, resulting in seal failure. At this time, the sealing assembly needs to be disassembled, and the end face needs to be repaired with a special grinding tool or replaced with a new part.
Insufficient spring pressure: Spring fatigue or improper assembly will cause a gap between the dynamic ring and the static ring, increasing the risk of leakage. This can be solved by adjusting the spring preload or replacing a high-strength spring.
Poor lubrication: If the cooling water contains corrosive substances, it may accelerate the aging of the sealing material. It is recommended to regularly test the cooling water quality and add an appropriate amount of corrosion inhibitor.

Details determine success or failure. The mechanical seal status verification of the stator cooling water pump DFB80-50-220 seems to be a simple operation process, but it actually contains rich technical details. From cleaning, assembly to dynamic testing, every link may affect the final sealing effect. Through scientific verification methods and rigorous operating specifications, users can not only effectively extend the service life of mechanical seals, but also provide solid guarantees for the stable operation of thermal power generators.

When looking for high-quality, reliable stator cooling water pumps, YOYIK is undoubtedly a choice worth considering. The company specializes in providing a variety of power equipment including steam turbine accessories, and has won wide acclaim for its high-quality products and services. For more information or inquiries, please contact the customer service below:
E-mail: sales@yoyik.com
Tel: +86-838-2226655
Whatsapp: +86-13618105229

Yoyik offers various types of power plants spare parts for steam turbines, generators, boilers as below:
Stop Valve J41H-16P
Check Valve H61Y-P55190V 12Cr1Mov
Stop Valve J61Y-P56160V
Electric Stop Valve J961Y-P51150V
Adjustable Vane Pump Pv7-1X/06-10Ra01Ma0-05Sp
Pump Main Pvh098R01Aj03A250000002001Ab010A
Gate Z41Y-16C
Electro Switch Sb01200-10W01A2
Gate Z561Y-40
Safety Valve A48Sh-64V
Gate Z40H-100
Ring,Seal 100Ay67X6-61
Vacuum Stop Valve Nkj61Y-100V
Opc Solenoid Valve Jz-Pk-002
Stop Valve J61Y-160I
Motor Hd1222-4A0 225M_45 Kw
Accumulator Bladder Nxq-A-10/20-F-Y-5
Steam Trap Cs69Y-600Lb
Stop Valve J61Y-P55.5190V 12Cr1Mov
Gate Z45Tx-10
Electric Stop Valve J961Y-P55.5190V Sa-182 F91
Electric Stop Valve J961Y-1550Spl
Hydraulic Servo Valve Dec21Nf58N
Accumulator Nxq-A-32-31.5L-Y
Stop Valve J61Y-250 Sa-105
Stop Valve J65Y-1500Lb
Orifice Plate 50Jlkb-300Lb