It’s common to be overwhelmed with indecision when presented with a bevy of options. You can get caught up in the details and feel too uninformed to make the right call in the moment. It happens to all of us. At Best Value Vacs, we often hear it from our customers in relation to our vacuum pumps: “Will someone just cut to the chase and tell me what the best choice is for me?” Yes, we will.
Before you reach your verdict, there’s more to consider than just the vacuum pump type. Diving in without knowing how deep the water is usually doesn’t bode well. The purchasing process becomes clearer once you’ve evaluated and reconciled the environmental factors that will be affected by your decision (and vice versa). As far as vacuum pumps go, you should consider the following:
The first step in choosing a vacuum pump is knowing how you are going to be applying it to best fit the needs of vacuum application. The application will determine whether or not you may need a rotary vane, diaphragm, scroll, chemically resistant, or belt-driven pump.
Be sure to evaluate the compatibility of the chemicals and gases in the application being used with the pump and the likelihood of issues arising from their interaction. A cold trap is always recommended with oiled vacuum pumps.
Vacuum Level and Flow Rate
The desired vacuum level you wish to achieve will determine the pump needed. In an application like rotary evaporation, a low vacuum level is usually not needed. However, in a process such as distillation, a very low vacuum level is needed to improve and speed up the processes. The flow rate of the vacuum pump is also important. Some applications may have a lot of volume that needs to be vacuumed down in a certain amount of time, like a large vacuum oven, while may require faster vapor flow such as short path distillation.
Pump Installation and Maintenance
The amount of initial setup and machine maintenance should be considered. Make sure to purchase everything needed to install and run your vacuum pump, for different applications may require distinct connection types and tubing. The pump may also need to be wired directly into a breaker.
The frequency of maintenance and expertise of operating the pump vary based on which type you choose, as well. (Maintenance tip: cold traps prevent vapors from recondensing inside the pump, extending the lifespan of your vacuum pump.)
The overall price of purchasing and maintaining the pump you need will affect your decision of whether to buy it outright, seek financing, or put it in the budget for the future. Knowing what pump is best for your application and you can afford is the basis of operating within your means and upholding value in all other areas of your business.
TYPES OF VACUUM PUMPS
Now, onto the different types of vacuum pumps from which to choose. The kind of vacuum pump you’ll select depends on its application. The different types vary in displacement capacities and ultimate vacuum levels.
Best Value Vacs recommends three main kinds of vacuum pumps: rotary vane, diaphragm, and scroll pumps. They are designed specifically for each respective application and used in industrial labs across the nation for freeze-drying, evaporation, vacuum purging, distillation, composites, and material testing.
Rotary Vane Pumps
The majority of rotary vane pumps are a great introductory product due to their lower upfront cost. They are small and compact, which makes them a terrific space-saving option if you’re looking for the right balance between form and function.
Rotary vane pumps do require oil for operation. The oil ensures a tight seal, well-lubricated moving parts, and excellent heat dissipation to cool the pump. Rotary vane pumps never have internal metal-on-metal contact, which means less wear and prolonged peak performance.
However, the oil does prompt more frequent maintenance because the oil is necessary for the pump to maintain solid operation.
A cold trap is always recommended when using an oiled pump because the oil will re-condense vapors and cause the performance of the pump to drop or the pump to seize up depending on the chemical vapors. The oil should generally be replaced after every 12 hours of use or once the oil starts to become discolored if you are not using a cold trap, but does not have to be replaced as often if the pump is used with a cold trap.
Rotary Vane vacuum pumps reach deep ultimate vacuum levels and have high displacement capacity. This makes them a good choice for freeze-drying applications. RV pumps work especially well for aqueous samples and solvents with high boiling points because vapors can be caught before they reach the pump.
Diaphragm pumps are dry pumps that operate via a pulsing motion that opens and closes diaphragms to shift air. They’re a great starting point because they’re mainly designed for applications such as rotary evaporation, dealing with volatile compounds, and continuous operation.
Diaphragm pumps do have a higher initial cost, but since they’re oilless, maintenance and operation costs are much lower than other oil-requiring pumps. Applications, however, are limited to lower vacuum levels, more chemically-demanding applications, or prolonged usage. The vacuum itself is not that deep, so a diaphragm pump cannot be used for freeze-drying.
Diaphragm pumps are extremely chemical- and corrosion-resistant. They can handle virtually any kind of viscous liquid or sample you use, even ones that contain a combination of solvents and acids. This makes them an ideal choice for evaporation and concentration.
Scroll pumps are dry pumps that use two spiral scrolls to compress air and vapors and push them out of the exhaust. In a way, you’ll feel like you’re running on inexhaustible fumes! The scrolls themselves are made of metal and do not fare well with high-acidity samples. They can, however, achieve deep vacuum volumes and increased displacement capacities.
The lack of oil makes scroll pumps very environmentally friendly. They process water vapors better than the majority of other pumps and are best used with aqueous and solvent samples. This makes them a great candidate for freeze-drying.
Scroll pumps do have higher upfront costs and are also loud during use, which can be problematic for some work environments. Because they don’t require oil, their overall maintenance costs can be lower than other pumps. The need to service the scrolls in the pump usually depends on the amount of use the pump is seeing. Depending on the pump, the scrolls may need to be completely replaced or just a seal replacement; however, this is downtime that some people can not afford.
Do you still have questions about our vacuum pumps? Contact Best Value Vacs today to speak with a professional who will walk you through the various brands we have in stock!