1. Leakage Occurring During Hydrostatic Test
(1) The seal faces are scratched, deformed or damaged during installation.
(2) Foreign particulate contaminants are trapped between seal faces due to inadequate cleaning during assembly.
(3) The set screws are loose or not fully tightened, and the gland plate (clamping plate for stationary ring assemblies of stationary-type seals) fails to achieve proper compression.
(4) Insufficient machining accuracy of equipment prevents full contact of seal faces.
(5) The secondary seals of rotating and stationary rings are not adequately compressed, with insufficient compression or damaged seals.
(6) V-rings for rotating and stationary rings are installed in reverse orientation.
(7) If leakage occurs at the shaft sleeve: the shaft sleeve seal is not sufficiently compressed, has inadequate compression or is damaged during assembly.
2. Periodic or Intermittent Leakage
(1) Excessive axial end play of the rotor assembly.
Remedy: Adjust thrust bearings to limit shaft axial end play to ≤0.25 mm.
(2) Periodic vibration of the rotor assembly.
Remedy: Identify and eliminate vibration sources.
(3) Frequent drastic pressure fluctuations inside the seal chamber.
Remedy: Stabilize process operating conditions.
3. Persistent Continuous Leakage
(1) Continuous leakage induced by defective seal faces
a. Insufficient spring compression (pre-compression of mechanical seal).
b. Excessive spring compression leading to cracking of graphite rotating ring.
c. Narrow seal face width resulting in poor sealing performance.
Remedy: Increase seal face width and correspondingly raise spring loading force.
d. Poor floating performance of the compensated sealing ring (over-hard secondary seals, aging after long service, insufficient compression, or too small clearance for the compensated ring).
Remedy: Increase the clearance of compensated sealing rings where clearance is inadequate.
e. Leakage at the joint of fitted or bonded rotating/stationary rings (poor fitting process, residual deformation, uneven material properties, uneven adhesive application and deformation).
f. Damage or cracks on rotating and stationary rings.
g. Severe wear of seal faces with loss of compensation capacity.
h. Deformation of rotating/stationary ring seal faces (excessive spring force on faces causes thermal deformation or eccentric wear due to increased friction; unreasonable structural design and insufficient strength of seal components lead to deformation under load; residual deformation from improper machining; uneven force applied during installation causes deformation).
Remedy: Replace defective or damaged sealing rings.
i. Excessive perpendicularity deviation of seal faces relative to the shaft centerline, and excessive parallelism deviation between rotating and stationary ring seal faces.
Remedy: Realign and adjust seal faces.
(2) Continuous leakage caused by secondary sealing elements
a. Improper seal material with inadequate wear resistance, corrosion resistance, temperature resistance and anti-aging performance, resulting in premature deformation, hardening, cracking or dissolution.
b. Incorrect compression of O-rings: excessive compression easily causes damage during installation; insufficient compression results in poor sealing effect.
c. Burrs, unpolished chamfers or insufficient chamfer radii exist on the surfaces of shaft (or shaft sleeve), seal gland and seal chamber where O-rings slide during assembly.
Remedy: Grind burrs and rough chamfers smooth, appropriately enlarge radii and chamfers and finish surfaces smoothly.
d. Chipping, cracking, impact damage, edge curling or torsional deformation of O-rings.
Remedy: Do not clean rubber seals with gasoline or kerosene; arrange and straighten seals properly during assembly.
(3) Leakage originating from defective springs
a. Skewed spring end faces.
b. Excessive difference in free length among individual springs for multi-spring mechanical seals.
GEN-MIXestablished in 2021, is a high-tech enterprise specializing in the R&D, production, sales, and providing customized services and solutions for mixed dispersion technology. The company mainly produces mixed dispersion machines and related systems, which are commonly used in the production of various chemical, dairy, cosmetics, pharmaceutical, food and other industries, and can be used to manufacture emulsions, creams, suspensions and other products. It can improve the stability, uniformity, and fineness of the product, and improve the quality and performance of the product.
