The cream of the crop: how the separator sparked a dairy revolution

Dairy Separation

The cream of the crop: how the separator sparked a dairy revolution

A prolific Swedish inventor improved on a basic principle of physics to produce a simple but ingenious device that revolutionized the dairy business and spawned a multibillion-dollar industry.

The basic physics of a separator is documented all the way back to Roman times. A simple earthenware bowl with a spout allowed two different mixed liquids to settle according to their physical density so the lighter liquid could be poured off.

This “sedimentation by gravity” was the original technique used in dairies to separate fat from milk. Left in a vessel, the fat globules from fresh milk floated to the surface to form a layer of cream, which was then skimmed off by hand. But the process was inefficient and often led to the milk turning sour.

The improvement and industrialization of this ancient method began when a young Swedish engineer by the name of Gustaf de Laval read an article that had been published in a German trade journal in 1877. The article described “a drum which is made to rotate and which, after turning for a time, leaves the cream floating on the surface so that it can be skimmed off in the usual fashion.”

Inspired, de Laval retreated to his workshop to improve on the concept and to lay the groundwork for its large-scale manufacturing. Two years later the Swedish daily newspaper Stockholms Dagblad reported that de Laval was demonstrating his centrifugal separator to interested observers in the city. “The machine can be likened to a drum which is driven round by a belt and a pullet,” wrote the newspaper’s correspondent. “The cream, which is lighter than the milk, is driven by centrifugal force to the surface of the milk and flows off into a channel from which it is led into a collection vessel. Under it, the milk is forced out to the periphery of the drum and is collected in another channel, whence it is led to a separate collecting vessel.”

In 1883 de Laval formed AB Separator to focus on manufacturing his revolutionary device for the milk industry. A few years later, pumps were developed by the company to attach to the separator to gather the skimmed milk and thereby increase capacity many times over.

The world’s first continuous separator using the new Alfa disc stack technology was introduced in 1890, and eight years later the first yeast separator was installed in a customer’s production line. By 1916 the applications for the technology expanded to oil purification on-board ships, and in later decades the same basic process was adapted to remove higher density microorganisms – spores and bacteria – from milk.

By the turn of the century, de Laval’s hand-cranked separators – and those of his many competitors – had become a common sight on dairy farms across US and Europe. Soon de Laval’s devices were being advertised as “world record machines” that could save dairy farmers a not insubstantial $3 to $5 per cow per year. According to the advertising, 98 percent of the world’s creameries were by then using de Laval separators.

Gustaf de Laval became one of Sweden’s most prolific inventors with 92 patents to his name. By the time he died in 1913 he had formed 37 companies.

His early separators have gone on to become collectors’ items – as have the vintage posters and signs advertising them. In the US and Canada there are said to be more than 60 “serious separator collectors” who enthuse over this milestone in industrial and agricultural history.

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