The substance was pressurized by the heat and the usage of a force pump.
From the en.wikipedia.org
It describes a traditional European force pump.
From the en.wikipedia.org
In 1689, Papin suggested that a force pump or bellows could maintain the pressure and fresh air inside a diving bell.
From the en.wikipedia.org
Water, at a pressure of 750 psi, was pumped into the accumulators by two 360 hpstationary steam engines, each driving a force pump from its piston tail rod.
From the en.wikipedia.org
Ctesibius is credited with the invention of the force pump, which Vitruvius describes as being built from bronze with valves to allow a head of water to be formed above the machine.
From the en.wikipedia.org
The best way to extract the remainder is to pump gas down to force the oil out.
From the economist.com
A new force main pump with a grinder is being installed to prevent future clogging issues.
From the orlandosentinel.com
Ethanol policies force motorists to pump expensive, energy-inefficient fuel into their cars.
From the kansas.com
The process involves a pump and compressor to force air through a line with holes in it.