METHOD OF BLENDING LUBRICANTS USING POSITIVE DISPLACEMENT LIQUID-HANDLING EQUIPMENT

The present invention relates to a method of dispensing accurately small amounts of high viscosity lubricant components using tubeless positive-displacement liquid-handling equipment for forming lubricant blends. The method includes the steps of: providing a low void volume positive displacement pipette with a tapered tip for each lubricant component contained within a lubricant additive reservoir, and one or more lubricant blend containers; ingesting into a low void volume positive displacement pipette from a lubricant additive reservoir an ingestion volume of a lubricant component; moving the low void volume positive displacement pipette from the lubricant additive reservoir to the one or more lubricant blend containers; ejecting into the one or more lubricant blend containers an ejection volume of the lubricant component from the low void volume positive displacement pipette; returning the low void volume positive displacement pipette from the one or more lubricant blend containers to the additive reservoir; and repeating these steps for each additional lubricant component. The advantages of the method of the present invention include improved dispensing accuracy, quicker dispensing, lower shear rate during dispensing, lower temperature for dispensing, less residual additive on the tip of the device after dispensing, and the ability to real time monitor density and mass during dispensing. The method finds application in laboratory test environments, and in particular in high throughput testing environments.