Video: Choosing the Best Vacuum Pump for Your Lab Application


Are you in the market for a new laboratory vacuum pump? Perhaps you need more information on which pump to choose. A new video, produced by Lab Manager, may provide valuable insights. View the video directly above, or click here.

How to Select a Pump for Rotary Evaporation

Application Note: LabEvaporation is one of the most common tasks performed in a chemistry laboratory. But, how do you go about selecting the correct vacuum pump for your rotary evaporator? Or, if you already have a vacuum pump, how do you know whether it is well-suited for this application?

The key to correctly selecting and sizing a vacuum pump for rotary evaporation can be found in your answers to the following four questions:

What solvents are you working with?

This is important due to the different boiling points of solvents. Solvents with a low boiling point, like acetone, methylene chloride and pentane, do not require as deep of an end vacuum to evaporate as solvents such as acetonitrile, benzene and chloroform. The removal of solvents with high boiling points, such as water, DMSO, DMF and toluene requires a relatively deep end vacuum. You must ensure that the pump is capable of reaching an end vacuum deep enough to remove the target solvents efficiently. For reference, see the Boiling Points Table.

This topic then naturally progresses to the need for chemical compatibility. Based on the solvent vapors going through the pump, one can determine the best materials for a long, trouble-free service life. Dry, oil-free pumps offer significant advantages in this area in comparison to rotary vane and water aspirators. In addition, they can feature premium, corrosion-resistant wetted parts, are easily maintained on site, and do not create hazardous waste.

Rotary Evaporator

What is the size of your evaporation flask?

This question allows you to select the best sized pump for your application. Bigger isn’t always better. A pump that is too large or has too high of a flow capacity for a given application is difficult to control, terribly inefficient and more expensive to own and operate. On the other hand, a pump that’s sized too small or doesn’t have enough flow capacity will slow the evaporation and lead to longer processing times. A pump that is used for a 250 mL flask is probably not the best pump for use with a 20 L evaporation flask, and vice versa.

What is the temperature of your heating bath?

The goal is to determine whether or not the pump is able to provide the necessary vacuum level and handle the vapor temperatures. The closer the bath temperature is to the boiling point of the solvent, the faster the rate of evaporation. If the mixture is not sensitive to elevated temperatures, increasing the bath temperature will speed the process and reduce the need for a deep vacuum pump. This may have an effect on which pump is best for the job.

How do you want to control the vacuum?

Manual, two-point, or adaptive control? Vacuum control allows for optimization of the vacuum level in the system. Optimum vacuum level shortens evaporation times and provides superior product yields. Control of the vacuum also reduces bumping and enables greater solvent recovery and repeatability.

  • Manual vacuum control involves the use of a stop cock or manual valve to adjust the vacuum level based on visual cues. Using this method, you will need to monitor throughout the process as the vacuum requirements may change throughout the evaporation.
  • Two point or on/off vacuum control allows the vacuum in the system to cycle between a high and low set point by turning the pump on and off. This method allows you to leave the process unattended once the min/max settings are determined.
  • Adaptive vacuum control provides the best results in terms of separation, speed and solvent recovery, and allows you to leave the process unattended once set. This type of control modifies the speed of the pump to precisely match the requirements of the process. It is the most accurate method; allowing for the system to operate at a specified vacuum level while responding to changing conditions without the need to monitor and adjust settings.

Ask An Expert

With answers to these five questions, you are now prepared talk to your supplier about proper pump selection, or to evaluate the suitability of the pump you already have. You can also use our easy online tool at Once there, click on the “Rotary Evaporator” icon, and enter your answers from the questions above. After clicking “Submit”, you will see a list of KNF vacuum pumps that meet your criteria. For further support, please contact us.

Click here for a printable PDF version.

RC 900 Rotary Evaporator Earns Red Dot Award for Product Design

Red Dot Award Winner: RC 900 Rotary Evaporator

We’ve seen the favorable impressions from the lab industry; we’ve heard the positive reviews from the academics who tested it. And while our customers currently put it through its paces, it’s a great honor to announce the RC 900 has won a Red Dot Award for product design. The RC 900 was selected from a pool of 4,815 applications, from 53 countries, so we don’t take this internationally-recognized and well-respected award lightly.

The reasons behind the award winning design, however, come from a combination of two great voices: the product designers at KNF Neuberger, and…you. That’s right, our design team was wise enough to simply ask our customers what they were looking for in their next rotary evaporator. As pump manufacturers, part of our mission has been to develop vacuum pumps that connect to rotary evaporation devices. Therefore, we’ve been hearing from customers for years about simple fixes that could improve their process.

The RC 900 is the result of these conversations. The instrument has all the traits of a KNF product; it’s built extremely well, has a very long product life, and is backed by KNF’s global support system. Simultaneously, it addresses major -and minor- “pain points” for lab scientists who spend the greatest amount of time with these products. After beta testing from our esteemed colleagues at Friedrich-Alexander-Universität Erlangen-Nürnberg, in Germany, and Oxford University in England, for further refinement, we’re extremely proud of the final product.

For example, some of the enhanced features on the RC 900 include:

  • Added safety with wireless remote control. Thanks to a Bluetooth remote control, you can simply dial in the characteristics the instrument needs to perform to – even from outside a closed fume hood. Touchscreen operation makes this job even easier.
  • Easy, fast flask exchange. Flasks can be exchanged quickly and easily, thanks to a new fastening clip that allows users to simply push the flask into the retainer until it locks into place. Removal is just as easy; to release, lift the fastening clip and remove the flask. A safety catch prevents the flask from slipping accidentally during removal.
  • Fully adjustable flask angle. Different flask sizes require adjustable pivoting to ensure the flask is properly immersed in the water or oil bath. Now, the optimum position can be set with ease using a fully adjustable control knob that adjusts the angle of the flask.
  • Space-saving, minimal footprint. Space on the bench is prime real estate. The reduced footprint of the RC 900 requires little bench space, and in return allows for a safer –and more organized- workspace.

Therefore, the Red Dot Award is validation for the effort we proudly put into the new RC 900 rotary evaporator. The combination of KNF ingenuity, and the strength of the customer input, has led to an instrument that leads the way into the new level of efficiency and effectiveness during rotary evaporation.

To learn more about the RC 900 rotary evaporator, visit

ACS Fall, from the show floor: New Rotary Evaporator Earns Attention; Our First Sweepstakes Winner Earns some Cash

Day two from the floor of the 248th ACS National Meeting & Exposition has arrived, and we’re excited by the attention our new RC 900 Rotary Evaporator has received. As pictured below, the KNF Lab team has been demonstrating the RC 900’s simplified and efficient operation here at booth #837. Ask about the wireless remote, touchscreen, or easy flask exchange.

Seeing the new RC 900 Rotary Evaporator for the first time

Susan Jones, Cathrine Jarinko, Kate Harrigan and John Hendricks, of the University of the Sciences, upon seeing the RC 900 Rotary Evaporator’s wireless remote for the first time, as demonstrated by Roland Anderson.

We’ve heard quite a few “oohs and aahs” over the features the product provides. For example, the simplified flask exchange has drawn more than one attendee to comment on how much easier it will make any chemist’s life. Also, we’ve seen students and well-seasoned chemists alike marveling at the wireless, Bluetooth–enabled controller with the ability to operate the instrument while the sash is closed. And though a seemingly innocuous feature, we had one attendee compliment the RC 900’s bath, which was designed with walls that are perpendicular to its base. Therefore, while being carried, it helps to prevent spills. Regarding the sleek design, one attendee simply said, “wow, that’s beautiful!”

Also, it’s time to announce the first winner of our giveaway, taking place during ACS Fall. Sharon Kirk, from the University of Utah, congrats! You’ve won the first of four Visa Gift Cards. If you have not yet entered the sweepstakes, stop by the KNF booth (#837) today or tomorrow, and check back to The Pump Post blog to find out if you’re a winner.

To learn more about the new RC 900 Rotary Evaporator, or our full line of vacuum and liquid pumps and systems for the laboratory applications, visit And don’t forget to drop by the booth this week!

Laboratory, Meet Bluetooth.

In March, we discussed our expectations for Pittcon 2013, and noted how some of the emerging trends parallel the benefits of our SC950 and SC920 vacuum systems. Specifically, these vacuum systems make use of an industry-first Bluetooth controller, which promotes not just form, but function throughout the lab. Let’s take a look at the advantages this technology yields in a scientific setting, and highlight the benefits along the way.

First, and perhaps most important, is the idea that this provides more than just wireless control. Utilizing Bluetooth eliminates traditional line-of-sight issues as well. This is critical in the lab,


KNF continues to bring innovation to the lab, introducing Bluetooth control to vacuum pump systems.

where both lab equipment and colleagues vie for limited benchtop space. If the vacuum system is stored below the bench or in a cabinet, the Bluetooth still functions as required. This is thanks to the same low-powered radio waves used to control garage door openers, modern cordless  phones, baby monitors and more. Therefore, Bluetooth control can actually help free up bench  space, as it allows the controlled vacuum system to be moved to an out of the way location and  still perform as needed. With the vacuum operating out of sight, lab personnel can redirect their efforts toward other processes while retaining full ability to control the system at the simple  click of a button.

An ever-growing topic in the lab (and one we’ll be discussing at length in the near future), energy savings and green initiatives aren’t just driving the way labs operate, but also the way the
equipment within them are purchased and used. Thanks to Bluetooth performance, SC950
and SC920 vacuum systems can be operated within a fume hood without the need
for annoying cable feedthroughs. Fume hoods, which consume a large amount of lab
HVAC conditioned air, are a sizeable contributor of wasted energy expenses in the lab. The  SC950 and SC920 Bluetooth control allows the hood to be continuously operated at maximum  efficiency even when making critical system control adjustments. In fact, according to California  Institute of Technology, a variable volume fume hood is 60 percent more energy  effective when the sash is down when not in use1.

Finally, Bluetooth promotes increased lab safety as well. As mentioned above, SC950 and SC920 vacuum systems can operate within the  fume hood with the sash closed, and without the need for any tether or cable feedthroughs. This allows researchers to confidently work with  hazardous or toxic chemicals from outside the fume and with a barrier in place, simply making use of the system remote control for additional lab safety.

Remember, laboratory equipment continues to evolve. The integration of Bluetooth controller technology into a portable vacuum system  offers many benefits that can be applied throughout your lab. To learn more about SC950 and SC920, or to learn how KNF Neuberger continually drives lab efficiency via world class pumps and systems, visit



PITTCON 2013: Trends & Expectations

By: Dan McDougall, Senior Manager – Laboratory Products

PITTCON approaches, and we’re looking forward to showcasing our stable of laboratory pumps and vacuum systems. Conferences and  tradeshows always provide a great opportunity to meet with co-workers and customers from across the country –or the globe. Today’s  tradeshows involve a lot of prep; exhibiting is only a part of the responsibility. We continually find additional value at shows by ensuring a  full schedule of meetings takes place. This face-time is critical, and it’s incredibly beneficial to meet with customers to discuss their lab  systems and setups in detail.

Simultaneously, it’s important to “see” our industry right in front of us. Shows like PITTCON are the perfect venue to learn about industry  trends, and to see if last year’s innovations are now driving growth throughout the market. Ideally, we take note of market-shaping topics  and use them to identify new applications for our products, in combination with our own processes of building pumps and systems that serve  distinct industry needs.

This year, I’m very interested in hearing the latest developments in the push for sustainability and green initiatives. Though it has been  discussed for years, I continually hear about companies pursuing LEED certification. LEED, or Leadership in Energy and Environmental  Design, is a voluntary, consensus-based market-driven program that provides third-party verification of green buildings. Creating pumps  and vacuum systems –or a full business culture– that aligns with these principles is a part of our corporate social responsibility, and there  are KNF Neuberger products that correspond with this mindset.

We’ll be showcasing our SC950 and SC920 Vacuum Pump Systems at PITTCON this year.
These systems promoteSC950cmyk 6x6 green initiatives in the lab, operating without the need for oil or aspirator water. That way, there’s far less waste created during the vacuum process. They also provide meaningful energy savings, thanks to a brushless DC (BLDC) motor. Once the desired vacuum has been reached, the BLDC motor operates only occasionally to maintain that level instead of running at full speed. This reduces energy as well as wear and tear.

Also, SC950 and SC920 vacuum systems utilize a first-of-its-kind Bluetooth-enabled control, allowing lab personnel to install the systems within the fume hood, with the sash fully closed. Not only does this help reduce energy costs, it also promotes a safer working environment and increases much-needed bench space. In fact, both of the vacuum systems can be installed on a shelf or even in a cabinet, and eliminating annoying cable feedthroughs.

You can find KNF Neuberger at PITTCON booth #2502. We’d love to discuss any of these topics, or how we can help you in the lab.