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Deposits on the product and/or atmosphere side of the mechanical seal (media sides of mechanical seals) can lead to loss of axial mobility (blocking) of the spring-backed seal face. A distinction is drawn between mechanically induced and thermally induced deposits. Mechanical deposits on the product side. Fibrous and especially long fibrous constituents of a pumped medium have a
tendency to plait at the helical spring in mechanical seals which are dependent on the
direction of rotation. Grainy and sticky pastelike constituents of a pumped medium can
fill the product-side cavities in mechanical seals which are independent of the direction
of rotation. Thermal deposits on the product side. Local underranging of the crystallization temperature of saturated solutions, overranging of the transformation temperature (e.g. caramelization of sugar juice) or great differences in temperature (e.g. calcium precipitation from hot water of high carbonate hardness) often give rise to solid deposits. Deposits on the dynamic O-ring on the atmosphere side prevent axial
adjustment of the mechanical seal Mechanical seal with closed O-ring groove The remedy is to prevent (through dead-end arrangement of the mechanical seal) or to intensify (through circulation of the pumped medium) the transfer of heat from the mechanical seal, or else to heat or cool the stuffing box and use mechanical seals with no empty space. Deposits on the atmosphere side Residues, decomposition (cracking) products and solidified remnants left after evaporation of the volatile or liquid components of leakage often lead to deposits on the shaft (sleeve) in the area of the shaft-side secondary seal. Depending on the other conditions and the type and quantity of deposits, the remedy is
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Mechanical seal featuring product side with protected spring backing
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