Author Archives: Khashayar Hajiahmad

When a Varnish Removal Unit Becomes a “Varnish Relocation Machine” A Real Turbomachinery Lesson on Temperature, Solubility, Shutdowns, and Hydraulic Valve Jamming In turbomachinery lubrication and hydraulic control systems, varnish removal is often discussed as if it is only a filtration problem. Install a varnish removal unit.Run it for some time.MPC drops.Oil looks cleaner.Problem solved.ContinueContinue reading “When a Varnish Removal Unit Becomes a “Varnish Relocation Machine””

Varnish Removal Units That Use a Cooler to Force Varnish Removal A Technical Article from a Turbine Oil Reliability Perspective In many turbine oil and hydraulic oil systems, varnish removal units are offered with a cooler installed before a depth filter, cellulose filter, electrostatic collector, or other fine filtration element. The basic concept is simple: Cool theContinueContinue reading “Varnish Removal Units That Use a Cooler to Force Varnish Removal”

Resistivity in EHC Phosphate Ester Fluids: The Parameter Many People Underestimate In steam turbine EHC systems, the fire-resistant fluid is not only a hydraulic medium. It is part of the turbine control reliability chain. It transmits command signals hydraulically to stop valves, control valves, intercept valves, and reheat stop valves. Because these systems often useContinueContinue reading “Resistivity in EHC Phosphate Ester Fluids: The Parameter Many People Underestimate”

How to Do Turbine Oil Failure Root Cause Analysis Considering Turbine Oil as an Asset — with ISO 55000 and ICML 55 in Mind By Khash — MLE Perspective In many plants, turbine oil failure root cause analysis is treated as a laboratory problem: “The TAN increased.”“The MPC is high.”“The RULER dropped.”“The oil is dark.”“TheContinueContinue reading “How to Do Turbine Oil Failure Root Cause Analysis”

How Varnish on Bearing Surfaces Affects the Coefficient of Friction A practical tribology article for turbomachinery, journal bearings, thrust bearings, and lubricated sliding contacts In turbomachinery lubrication, varnish is often discussed as a cleanliness, oil degradation, or servo valve reliabilityproblem. But in rotating equipment, varnish is also a friction problem. When varnish deposits form on bearing surfaces, thrust pads,ContinueContinue reading “How Varnish on Bearing Surfaces Affects the Coefficient of Friction”

Directed Lubrication in Double Thrust Bearings — and What Varnish Does to These Critical Areas The image shows directed lubrication arrangements for double thrust bearings, designed specifically to prevent bulk oil from contacting the thrust collar. This is an important detail in turbomachinery because the thrust collar is a high-speed rotating surface. If excessive oil is allowedContinueContinue reading “Directed Lubrication in Double Thrust Bearings — and What Varnish Does to These Critical Areas”

Repeatability and Reproducibility Calculations in Turbine Oil Analysis Turbine engineers sometimes take one oil sample from the same turbine reservoir, split it into two or three bottles, and send the bottles to different laboratories. The objective is simple: “Let us compare the laboratories and see which one is accurate.” Then the reports come back, andContinueContinue reading “Repeatability and Reproducibility Calculations in Turbine Oil Analysis”

Turbomachinery Major Inspections and Turnarounds How Turbine Oils Must Survive Until the Next Planned Outage In modern power plants, LNG facilities, refineries, petrochemical plants, compressor stations, offshore platforms, and steel industries, turbomachinery is expected to operate continuously for years between major inspections. During this period, turbine oil becomes one of the most critical reliability assetsContinueContinue reading “Turbomachinery Major Inspections and Turnarounds”

All Khash Practical Experiences in the Field From Machinery Lubrication to Turbine Oil Reliability, Varnish Control, Oil Analysis, and Bearing Failure Learning Introduction: Practical Experience Is Not Written in Certificates Alone In the lubrication and reliability field, knowledge does not come only from books, standards, certificates, or training courses. Real knowledge comes when theory meetsContinueContinue reading “All Khash Practical Experiences in the Field”

Deeper Technical Review: All Synthetic Oil Types Used in Turbomachinery Synthetic oils are not one family. They are several different lubricant chemistries, each with very different strengths, weaknesses, compatibility limits, and turbomachinery applications. In turbomachinery, the word synthetic can include: PAO — Polyalphaolefin Synthetic esters PAG — Polyalkylene glycol Phosphate esters Polyol esters Diesters Alkylated naphthalenes SiliconeContinueContinue reading “Deeper Technical Review: All Synthetic Oil Types Used in Turbomachinery”