5 Questions TO ASK WHEN PURCHASING A VACUUM PUMP
Vacuum pumps are used throughout research labs for a variety of applications. Because of the broad array of uses and different pump technologies available, selecting the right pump for your application can be a challenge. Before you decide on a specific solution, asking yourself these five questions will help you select the most appropriate pump for your laboratory needs.
1. How much vacuum do I need?
Defining how much vacuum, or pressure below atmospheric pressure, is needed is the first step to selecting the most appropriate pump. Knowing the depth of vacuum your process requires, will determine your pump technology options. For example, diaphragm pumps can support operations down to about 2 mbar. This addresses common process such as filtration, degassing, drying, and many distillations; however, it is not deep enough for applications like freeze drying. For operations that require deeper vacuum, other technologies such as rotary vane and screw vacuum pumps are necessary. Lastly, when using vacuum for analytical instruments, often the high and ultrahigh vacuum capability of turbomolecular pumps is required.
2. How much pumping speed do I need?
The rated pumping speed is the maximum flow that the pump produces, which occurs when the pump generates the minimum pressure differential between its inlet and outlet. In most applications, you need to move air, gases, or vapors under vacuum conditions so the pumping speed you need is not the maximum rated pumping speed but the pumping speed at the working vacuum of your application. To learn this, you need to look at the performance curve of the pump or consult your manufacturer’s rep. If you get this incorrect, your process may take longer than anticipated.
3. How noisy will it be?
Noise generated by equipment can be disruptive and make for a challenging working environment. While many think of all vacuum pumps as noisy, some types of pumps are inherently more noisy than others. Generally speaking, a diaphragm pump will be quieter than an equivalent piston pump, so selecting a quieter pump that meets performance specification can have a meaningful impact on background noise in the lab.
4. What maintenance is required and how often?
Pump maintenance requirements—or lack thereof—have a significant impact on product lifecycle costs. For example, some pumps require regular maintenance and rebuilds whereas other types of pumps are relatively low maintenance. For pumps that require frequent maintenance, also consider the cost of downtime when the pump is unavailable. Make sure to factor in maintenance and service considerations when selecting your new lab vacuum pump.
5. Do I need vacuum control?
Picking the right pump for your vacuum process also means considering whether you need the full design vacuum level of the pump or whether you need to set the vacuum to a range of values. Unless you are using vacuum for uncontrolled evaporation, the best vacuum for your application is not always the deepest but the right vacuum level. Vacuum that is too deep may cause unwanted bumping or foaming or evaporate process liquids. To achieve the right vacuum, you may need a pump with control capabilities.
