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General Centrifuge Maintenance

A User's Guide to Proper Cleaning and Operation

The Centrifuge: User Maintenance

A wide variety of centrifuges are used in the laboratory. Since particular speeds and times areessential for repeatability, a careful record must be kept of centrifuge speed, calibration, and timerchecks. To maintain proper functioning, the centrifuge must be inspected and cleaned regularly, partsneed to be lubricated as indicated in the owner's manual, speed must be checked and calibrated,timer accuracy must be verified on a monthly basis, and a record of repairs and service calls must bekept.User care of the centrifuge is generally related to the cleanliness of the rotor chamber, rotors and theiraccessories. This ensures good operation, prevents corrosion, and extends its life. Clean the entiresample chamber, rotor, and lid at the end of each 8-hour shift and right after any spill.1. Thoroughly clean the sample/rotor chamber, cabinet, suction feet and accessories: use a sponge

dampened with warm water and a mild detergent such as Caltech Rotor Wash. Inspect allsurfaces under bright light for corrosion; small crevices will eventually deepen and causefailure.

Do not use acetone, caustic detergents, or detergents that contain chlorine ions. Corrosion ismost frequently caused by using chloride ion solutions, such as sodium chloride (saline), andsodium hypochlorite (household bleach).

2. Remove stubborn stains with a plastic scrub pad. Scrub the rotors tube cavities with a stiff test-tube brush that has end bristles and a non-metallic tip.

Do not use steel wool, wire brushes, abrasives, or sandpaper, since they create corrosion sites.3. NEVER pour water directly into the sample chamber.4. After cleaning, dry the aluminum accessories with a soft cloth or put them in a drying oven (rotors

and buckets must never be heated > 50OC).

5. The trunnions of swing-out rotors must be lightly lubricated to avoid jerky movements of thebuckets. Lubricating should be done regularly (once per week). Before oiling, the bucket groovesshould be thoroughly cleaned with a dry cloth. In no case may organic solvents, alkaline orhousehold scouring powder be used!

NOTE:a) Molycote and graphite lubricants are not permitted.b) Motor bearings are lubricated for the motors life.c) No liquids or organic solvents should penetrate the annular slot around the motor shaft which

might wash the grease from the bearings.6. Decontamination or disinfection is required if tube breakage occurs and infectious, pathogenic, or

radioactive material is released into the unit. If spillage is confined to the polypropylene rotor, itmay besufficient to decontaminate the rotor, with a one-to-ten dilution of Ostro San, orradioactivity decontamination washes.

Ostro San, a non-acidic Quaternary Ammonium Disinfectant is useful as a general disinfectantand sanitizer. In use-dilutions is safe on aluminum, anodized aluminum, chromium oxide, steel,stainless steel, plastic, gold, chrome-plated, equipment parts (brass and copper fittings).

7. Autoclaving

Refer to operator manual - generally metal components should not be autoclaved.

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8. Glass BreakageGlass splinters must be removed immediately from the buckets, adapters and rotor chamber. Theglass splinters can damage the surface protection or could get stuck on the trunnions of theswing-out rotors and impair smooth movement of the swinging buckets.When glass splinters get into the rotor chamber and are whirled around by air circulation, a very

fine (black) metallic dust can develop. Metal abrasion can contaminate the rotor chamber, rotor,buckets and samples. With a strip of petroleum jelly (Vaseline) or trunnion grease appliedvertically on the chamber wall (from top to bottom) the glass dust can be captured with a gentlecentrifugation cycle and removed by wiping with a soft cloth.

9. Condensed Water (for all refrigerated centrifuges)Air, humidity, or non-hermetically sealed samples can cause condensation inside the rotorchamber. The liquid must be removed from the rotor chamber regularly (e.g. with a dry cloth).

10. For major service such as lid lock adjustments, testing for imbalance cut-out, refrigerationcondensor cleaning, and general repairs contact Caltech Tech Services or any other reputable labequipment repair company.