Single Spring Mechanical Seal Replacement for Alfa Laval Pumps with 316 Stainless Steel and -40°C to +200°C Temperature Range

A1: This seal is engineered as a direct interchange for Alfa Laval LKH and LK series pumps, specifically designed to match the original housing dimensions and shaft specifications. Compatibility extends to models with the same shaft diameter and seal chamber design, ensuring proper mechanical alignment and spring loading.

A2: This extended thermal stability allows the seal to handle cryogenic fluids as well as high-temperature processes including thermal oil systems and HTF applications. The wide range is achieved through specialized elastomer selection—typically FKM for chemical resistance or EPDM for steam service—coupled with matched thermal expansion coefficients in the face materials to prevent premature failure during thermal cycling.

A3: Standard configuration features silicon carbide versus carbon, providing optimal balance between cost and performance for most applications. For abrasive services or extended seal life, we recommend upgrading to silicon carbide versus silicon carbide face pairs. In chemical services with potential crystallization, tungsten carbide versus carbon offers superior particle-embedding characteristics.

A4: The seal is designed as a true drop-in replacement, requiring zero pump modifications. It maintains identical installation dimensions, gland spacing, and shaft requirements as the original Alfa Laval component. Proper installation requires standard mechanical seal fitting tools and verification of face squareness within 0.0005 inches per inch of shaft diameter.

A5: The seal operates effectively at pressures to 1.2 MPa (174 psi) in standard configuration. For higher pressure applications to 2.0 MPa, a balanced version with modified face geometry is available, which incorporates a step in the seal face to reduce hydraulic closing forces and prevent face separation under elevated pressure conditions.

A6: The single spring construction provides uniform loading across the seal faces, minimizing distortion that can occur with multiple spring designs. The spring is manufactured from 316 stainless steel with a polished surface finish to resist clogging from process media and maintain consistent face pressure throughout the seal's service life.

A7: Essential installation verifications include: shaft runout not exceeding 0.002 inches TIR; face perpendicularity within 0.001 inches; shaft axial float limited to 0.005 inches maximum; and seal chamber bore concentricity within 0.002 inches TIR. Proper flush line configuration should maintain at least 0.5 GPM flow for cooling in high-temperature applications.

A8: While the silicon carbide face materials provide good abrasion resistance, for sustained operation with abrasive slurries we recommend installing an external flush line with a cyclone separator or filter rated to 25 microns maximum particle size. Alternative arrangements include a quench gland with steam or clean water injection to prevent solids accumulation in the seal chamber.