To determine whether the seal of the hydraulic ceramic plunger pump needs to be replaced, it is necessary to comprehensively judge based on the wear and aging characteristics of the seal and the operating performance of the pump. Seals (such as O-rings, combination seals, guide rings, etc.) are key components that prevent medium leakage and hydraulic oil leakage. Their failure can lead to decreased efficiency, environmental pollution, and even damage to other components (such as ceramic plungers). The following is the specific method of judgment:

　　1、 Direct observation and judgment through appearance

　　When regularly disassembling and inspecting seals, the following appearance features can be used to determine whether they have failed:

　　Signs of aging

　　The surface of the seal appears hardened, cracked, and brittle (with no elasticity when pressed with fingers or easily broken by gentle pulling), commonly found in seals that have been in long-term contact with high-temperature media or hydraulic oil.

　　Surface softening and swelling (significant increase in volume, loss of original shape) are often caused by incompatibility between the sealing material and the medium/hydraulic oil (such as contact between nitrile rubber and gasoline, ketone solvents).

　　Wear and damage

　　Scratches, notches, and burrs on the lip or contact surface of the seal may be due to the uneven surface of the ceramic plunger (with fine impurities attached), scratches during installation, or wear of the guide sleeve causing the plunger to rub against the seal.

　　Uneven wear of the cross-section (thinning on one side and normal on the other) is usually caused by a deviation in the coaxiality between the plunger and the seal, or uneven stress on the seal due to the tilted installation of the pump body.

　　Deformation and crushing

　　The seal may be "compressed" or permanently deformed (such as the O-ring section changing from circular to flat), which may be due to the bolt being too tight during installation (exceeding the specified torque), or the sealing groove size not matching.

　　2、 Judging by abnormal performance during runtime

　　Even without disassembly, seal failure can be indirectly determined by the operating status of the pump, with common manifestations as follows:

　　Leakage phenomenon

　　Medium leakage: If there is dripping or leakage at the sealing part where the plunger contacts the pump head (visible water droplets when conveying clean water, and discoloration marks may accompany when conveying corrosive media), it indicates that the main seal (such as the plunger seal) has failed.

　　Hydraulic oil leakage: There are oil stains at the sealing point between the hydraulic cylinder and the plunger, or hydraulic oil droplets at the bottom of the pump body, which are mostly caused by damage to the cylinder seals (such as piston seals and dust seals).

　　Abnormal pressure and flow rate

　　The export pressure continues to decrease and cannot reach the set value. After ruling out the possibility of inlet blockage, it may be due to seal leakage causing pressure loss.

　　Flow instability or attenuation, especially under high pressure conditions, is more pronounced due to ineffective sealing of the seals, resulting in medium backflow.

　　Abnormal noise or temperature rise

　　After the seal wears out, the friction between the plunger and the seal increases, which may produce a "squeaking" friction sound.

　　If the hydraulic oil seal fails, oil leakage will cause the system to lack oil, insufficient lubrication in the pump, and abnormal oil temperature rise (over 70 ℃).

　　3、 Determine based on usage environment and cycle

　　Even if there are no obvious signs of failure, it is necessary to replace it in advance according to the working conditions:

　　Adverse environment

　　Transporting corrosive media (such as acidic and alkaline solutions): Seals are prone to corrosion, and it is recommended to inspect them monthly and replace them every 2-3 months (even if the appearance is intact).

　　Medium containing particles (such as slurry, mud): Particles will accelerate the wear of seals, and replacement is mandatory every 1-2 months.

　　High temperature environment (medium or ambient temperature ≥ 60 ℃): The aging rate of seals is accelerated, and the replacement cycle is shortened by 50% (such as the conventional cycle of 6 months and the replacement cycle of 3 months under high temperature).

　　Normal operating conditions

　　Transport clean, room temperature media (such as water, lubricating oil): It is recommended to check every 6 months and replace them once a year to avoid sudden failure due to aging.

　　4、 Precautions for replacing seals

　　When replacing, it is necessary to choose materials that are compatible with the medium (such as fluororubber acid and alkali resistant, nitrile rubber oil resistant, polyurethane wear-resistant) to avoid rapid failure caused by incorrect material selection.

　　Before installation, lubricate the seals with clean hydraulic oil or medium (avoid using engine oil as it may react with the medium), and ensure that the plunger surface is free of scratches and impurities to prevent damage to the new seals during installation.

　　When tightening bolts, use a torque wrench and operate according to the specified torque (refer to the equipment manual). If it is too loose, it will leak, and if it is too tight, it will crush the seal.

　　By using the above methods, it is possible to promptly determine whether the seal has failed, avoiding more serious faults such as medium leakage and pump body wear caused by delayed replacement, while extending the life of core components such as ceramic plungers.