Short-path distillation is a distillation technique where the distillate travels a short distance at reduced pressure in order to separate the liquid into different compounds. In the case of the cannabis industry, short-path distillation allows different cannabis components (including THC and CBD) to be separated from the crude cannabis oil that has been extracted from the cannabis plant. The result? Isolated CBD and THC compounds that can reach a purity level of over 80%.

How Are Vacuum Pumps Used in Cannabis Distillation?

During the traditional distillation process, the crude cannabis oil is heated to a certain temperature. At this point, the solution evaporates and the THC/CBD vapor rises to the top of the short-path distillation unit – and is then condensed back into a liquid, effectively separating it from the other substances present in the crude cannabis oil.

However, using heat in the distillation process can change the inherent nature of the compounds in the crude cannabis oil. This is where industrial vacuum pumps come in! By using a vacuum pump instead of heat to reduce the pressure and power the distillation taking place, the liquid mixture will be separated into different compounds. The reason is simple:  the vacuum pump will pull at different pressures, and these different pressures that are induced by the vacuum will separate the mixture into compounds of different chemistries.

Different Types of Vacuum Pumps Used for Cannabis Distillation

Vacuum pumps are a necessary piece of equipment required for proper hemp distillation. After extracting THC and CBD from hemp, it must undergo an evaporation process so that only the desired material remains. Without distillation equipment, this process requires extremely high temperatures—according to Julabo, “THC’s and CBD have high boiling points (156-250°C; 312-482°F)”—and can take extensive amounts of time to complete. To make this process easier, consider utilizing one of these different types of vacuum pumps used for hemp distillation.

Diaphragm Pumps

Because diaphragm pumps don’t use oil, they are corrosion resistance and low maintenance. Additionally, these pumps reduce the risk of oil contamination, oil mist, and eliminate the possibility of over-processing. While they may have a higher up-front cost than other vacuum pumps, they are durable and have a low cost of ownership fees which makes them a sound financial investment.

Rotary Vane Pumps

Rotary vane pumps are one of the cheaper vacuum pump options. These high-performance pumps can reach optimum vacuum levels and include changeable displacement capacities. Over time, however, they often accrue additional upkeep costs. Because they use oil, they may need regular maintenance to keep them working long-term.

Hybrid Pump

Combining both a diaphragm and rotary vane, the hybrid pump is an ideal option for corrosion resistance. By keeping a negative pressure on it in the rotary pump, the diaphragm pump prevents solvents and pollutants from condensing in the oil. In doing so, it reduces the concentration of oxygen and corrosive gases which allows the oil to last much longer than in other pumps.

Diffusion Pumps

Diffusion pumps are highly reliable pieces of equipment that push gas molecules out of the exhaust using a high-speed jet of vapor. To capture the gaseous molecules, this equipment requires boiling oils. These oils are typically either polyphenyl ethers or silicone oil which can be costly.

Regardless of the pump you pick, good maintenance is critical to keeping them buckling down for a long time to come. A vacuum trap or cold trap ought to be used to catch vapor getting away from the reaction vessel and shield the unit from harsh synthetic substances. Oil ought to be changed in oil-based pumps as per the manufacturer’s directions. Read the product manual properly for your pump to be sure it is legitimately maintained over the course of time.

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