What mechanical wear problems are most likely to occur in large-caliber mechanical water meters during long-term operation

Impeller wear caused by fluid impact
Large-diameter mechanical water meters rely on rotors or propellers to transmit flow during the metering process. Over long-term operation, transient impacts in the water flow can cause continuous erosion of the impeller. Turbulence at high flow rates can cause tiny indentations on the impeller edge, affecting rotational sensitivity. Flow fluctuations in some water supply networks, particularly in areas where pumping stations frequently start and stop, can significantly increase the instantaneous impact forces on the impeller, significantly accelerating wear. Impeller imbalance can reduce metering accuracy and potentially increase meter noise.

Bearing and rotating component wear
Large-diameter mechanical water meters typically use alloy or ceramic bearings to support rotating components. Over long-term operation, tiny particles in the water can enter the bearing clearances, increasing friction. Continuous wear can cause the bearing surface to lose lubricity, resulting in a loss of smooth rotation of the rotor or propeller. Bearing wear not only affects metering accuracy but can also cause internal mechanisms to seize, preventing the meter from starting properly under low flow conditions. In some areas, where water hardness is high, scale deposits can also exacerbate bearing wear.

Wear and Fatigue in the Gear Transmission System
Large-diameter mechanical water meters rely on a gear train to convert the rotation of the impeller into readings for the pointer or dial of the counting mechanism. Over long-term operation, the gear teeth can become thinner due to friction, leading to wear or poor meshing. Excessive gear clearance can cause "tooth skipping," resulting in erroneous readings. Some water meters operate in high-flow ranges, subjecting the gears to heavy loads. Metal fatigue can lead to microcracks on the tooth surfaces and ultimately to the risk of tooth breakage. Gear wear directly impacts the stability of the entire meter and is a common failure mode in large-diameter mechanical water meters.

Aging and Wear of Seal Components
Large-diameter mechanical water meters must maintain excellent sealing performance in environments with high pressure and prolonged immersion in water. Rubber seals gradually age over time, experiencing reduced elasticity and surface cracking. Aged seals can easily allow water to seep into the gearbox, causing lubrication failure and corrosion. Some water meters installed outdoors are subject to temperature fluctuations, accelerating the aging of seals in alternating hot and cold environments. Seal failure can also cause fogging on the dial, affecting reading clarity.

Wear of the magnetic coupling mechanism.
Some large-diameter mechanical water meters use a magnetic coupling transmission system to isolate the wet and dry areas, preventing the counting mechanism from being affected by water quality. Over long-term operation, the magnetic material's magnetism weakens due to friction and foreign particle intrusion during continuous rotation. This reduced magnetic force reduces transmission efficiency, and the counting pointer may lag or malfunction. Furthermore, strong external magnetic interference can accelerate wear and failure of the magnetic coupling components. These issues are particularly prominent in long-term operation and require regular inspection.

Wear of the inner wall of the meter case due to water erosion.
The inner wall of large-diameter mechanical water meters is constantly exposed to high-speed water flow, and some areas may experience vortex impacts due to changes in the flow direction. This can cause localized corrosion and wear on the metal case. Increased inner wall roughness increases fluid resistance, further affecting the meter's pressure drop performance. Long-term wear can also lead to impurity deposits, gradually rendering the meter ineffective in providing high-precision measurement.

Mechanical Fatigue of the Indicating Mechanism
The pointer and dial wheel mechanism of large-diameter mechanical water meters are subjected to continuous stress during long-term operation, and the gear shafts and connecting components are prone to mechanical fatigue due to repeated movement. Plastic gears or lightweight materials can deform due to long-term friction, causing errors in the reading display. Inaccurate readings directly affect the accuracy of water supply company billing and increase maintenance costs.

Water Quality Factors Exacerbate Wear
In actual use, water quality conditions significantly affect the wear of large-diameter mechanical water meters. Water containing sediment, rust, hardness ions, or corrosive components accelerates the wear of impellers, bearings, and gears. Mechanical wear is particularly prominent in industrial areas or aging pipe networks, where high levels of sediment accumulate in the pipes. Over extended operation, these impurities can cause rotating components to jam, or even lead to meter failure.