| In 1650, Otto von Guericke invented the vacuum | | | | The last category is the momentum transfer |
| pump. The vacuum pump was designed to | | | | pump, which is also called molecular pump. This |
| remove gas molecules from a sealed volume so | | | | type works by using a high-speed jet of dense |
| that it would leave behind a partial vacuum. | | | | fluid or a high -speed rotating blade that knocks |
| They are categorized into three main groups. The | | | | the gaseous molecules out of the chamber. With |
| three main groups are positive displacement, | | | | this type of pump the gas molecules are |
| entrapment and momentum transfer. The positive | | | | increased from the vacuum side to the exhaust |
| displacement pump uses a technique that | | | | side. |
| repeatedly expands the cavity. In doing this it | | | | This kind of pump can only work at pressures |
| allows the gases to flow in from the chamber | | | | below of 1kPa. The matter moves differently |
| then seal off the cavity, and then it disperses it | | | | depending on the pressure that is flowing through |
| into the air. | | | | the pump. This is based on the laws of fluid |
| The principal behind a positive displacement pump | | | | dynamics. There are two main types of |
| is that is the easiest way to make an artificial | | | | momentum transfer pumps. They are diffusion |
| vacuum to expand the volume of a container. | | | | pump and turbo molecular pump. These two kinds |
| The need for this type of pump was because | | | | of pumps blow out the gas molecules that spread |
| liquids cannot be pulled so it is impossible to create | | | | out into the pump by giving momentum to the |
| a vacuum by suction. The best example of this | | | | gas molecules. |
| type of pump is the diaphragm muscle. It works | | | | The turbo molecular uses a high -speed fan to |
| just like a positive displacement pump; it expands | | | | push the gases. But the diffusion pump works |
| the chest cavity, which causes the volume of the | | | | differently it blows out the gas molecules with a |
| lungs to increase. | | | | jet of oil or mercury. But both of these kinds of |
| The entrapment pump works differently. It uses | | | | pumps will stall and fail to pump if they are |
| cold temperatures condense gases to a solid or | | | | exhausted directly to atmospheric pressure. They |
| adsorbed state. The pump works by trapping the | | | | must be exhausted to a lower grade vacuum |
| molecules in a confined space. It works like a | | | | that is created by a mechanical pump. |
| cryopump. They trap the liquefied gas molecules | | | | There are different types of vacuum pumps, but |
| in a cold trap and then the ion pump uses the | | | | they all a very specific purpose. |
| ionized gas that is magnetically confined. | | | | |