Steam digester
Encyclopedia
The steam digester is a high-pressure cooker invented by French physicist Denis Papin
Denis Papin
Denis Papin was a French physicist, mathematician and inventor, best known for his pioneering invention of the steam digester, the forerunner of the steam engine and of the pressure cooker.-Life in France:...

 in 1679. It is a device for extracting fats from bones in a high-pressure steam environment, which also renders them brittle enough to be easily ground into bone meal
Bone meal
Bone meal is a mixture of crushed and coarsely ground bones that is used as an organic fertilizer for plants and formerly in animal feed. As a slow-release fertilizer, bone meal is primarily used as a source of phosphorus....

. It is the forerunner of the autoclave
Autoclave
An autoclave is an instrument used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents. It was invented by Charles Chamberland in 1879, although a precursor known as the...

 and the domestic pressure cooker.

The steam-release valve, which was invented for Papin's digester following various explosions of the earlier models, inspired the development of the piston-and-cylinder steam engine
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

.

History

Artificial vacuum was first produced in 1643 by Italian scientist Evangelista Torricelli
Evangelista Torricelli
Evangelista Torricelli was an Italian physicist and mathematician, best known for his invention of the barometer.-Biography:Evangelista Torricelli was born in Faenza, part of the Papal States...

 and further developed by German scientist Otto von Guericke
Otto von Guericke
Otto von Guericke was a German scientist, inventor, and politician...

 with his Magdeburg hemispheres
Magdeburg hemispheres
The Magdeburg hemispheres are a pair of large copper hemispheres with mating rims. When the rims were sealed with grease and the air was pumped out, the sphere contained a vacuum and could not be pulled apart by teams of horses...

. Guericke's demonstration was documented by Gaspar Schott
Gaspar Schott
Gaspar Schott was a German Jesuit and scientist, specializing in the fields of physics, mathematics and natural philosophy, and known for his piety.-Biography:...

, in a book that was read by Robert Boyle
Robert Boyle
Robert Boyle FRS was a 17th century natural philosopher, chemist, physicist, and inventor, also noted for his writings in theology. He has been variously described as English, Irish, or Anglo-Irish, his father having come to Ireland from England during the time of the English plantations of...

. Boyle and his assistant Robert Hooke
Robert Hooke
Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...

 improved Guericke's air pump design and built their own. From this, through various experiments, they formulated what is called Boyle's law
Boyle's law
Boyle's law is one of many gas laws and a special case of the ideal gas law. Boyle's law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system...

, which states that the volume of a body of an ideal gas is inversely proportional to its pressure. Soon the ideal gas law
Ideal gas law
The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation to the behavior of many gases under many conditions, although it has several limitations. It was first stated by Émile Clapeyron in 1834 as a combination of Boyle's law and Charles's law...

 was formulated.

Based on these concepts, in 1679, an associate of Boyle's named Denis Papin
Denis Papin
Denis Papin was a French physicist, mathematician and inventor, best known for his pioneering invention of the steam digester, the forerunner of the steam engine and of the pressure cooker.-Life in France:...

 built a bone digester, which is a closed vessel with a tightly fitting lid that confines steam until a high pressure is generated. Later designs implemented a steam release valve to keep the machine from exploding. By watching the valve rhythmically move up and down, Papin conceived of the idea of a piston and cylinder engine. He did not, however, follow through with his design. Nevertheless, in 1697, based on Papin's designs, engineer Thomas Savery
Thomas Savery
Thomas Savery was an English inventor, born at Shilstone, a manor house near Modbury, Devon, England.-Career:Savery became a military engineer, rising to the rank of Captain by 1702, and spent his free time performing experiments in mechanics...

 built the world's first steam engine.

Boyle speaks of Papin as having gone to England in the hope of finding a place in which he could satisfactorily pursue his favorite studies. Boyle himself had already been long engaged in the study of pneumatics, and had been especially interested in the investigations which had been original with Guericke. He admitted young Papin into his laboratory, and the two philosophers worked together at these attractive problems.
He probably invented his "Digester" while in England, and it was first described in a brochure written in English, under the title, "The New Digester." It was subsequently published in Paris.

This was a vessel, B, capable of being tightly closed by a screw, D, and a lid, C, in which food could be cooked in water raised by a furnace, A, to the temperature due to any desired safe pressure of steam. The pressure was determined and limited by a weight, W; on the safety valve lever, G. It is probable that this essential attachment to the steam boiler had previously been used for other purposes; but Papin is given the credit of having first made use of it to control the pressure of steam.

In 1787, Antoine Lavoisier
Antoine Lavoisier
Antoine-Laurent de Lavoisier , the "father of modern chemistry", was a French nobleman prominent in the histories of chemistry and biology...

, in his Elements of Chemistry, refers to "Papin's digester" and discusses how the strong compression of water and other liquids in it, which is able to sustain a red heat, creates artificial atmospheres, which may potentially be able to soften or liquefy stones, salts, and the various parts of the earth.

External links

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