Syringe pumps are a popular choice for both microfluidics flow control and dispensing applications due to ease of set up and high precision. Using a stepper motor and lead screw, syringe pumps are capable of continuously moving the syringe plunger extremely small distances, as low as a couple hundred nanometers, to generate constant flow. And setting the flow is as straightforward as multiplying the inner cross sectional area of the syringe by the travel rate, making it a quick plug-and-play flow control solution for many applications.

So what things should be considered when looking to upgrade from that entry-level, red one that everyone has? Or is the red one good-enough for your needs? We'll cover some common specs and features to consider when shopping for a new syringe pump.

Pricing and Warranty

Cost is likely the first thing many consider when looking for equipment. Is the price and warranty period within budget to consider a purchase? If cost is never an issue, then the highest-performance pump is probably the best choice for you.

Flow Rate Limits & Syringe Compatibility

The lowest achievable flow rate will depend on the minimum travel distance of the end block which is achieved by the motor's smallest step size and lead screw combination. Additionally, the smallest inner diameter syringe compatible with the mounting slots will ultimately dictate the minimum flow rate.

Meanwhile, the maximum flow rate will rely on the motor's max step rate, largest inner-diameter compatible syringe, and the linear force (more later). A large inner diameter syringe with a fast step rate will enable a large flow rate.

Additionally, syringe pumps can cover a large range of flow rates if they are compatible with many different syringes, such as a 0.5 µL glass syringe to a 150 mL plastic syringe.

Accuracy

Manufacturers publish an accuracy specification. With entry level syringe pumps having at least ±1% accuracy, one should look for an accuracy specification of 0.35% or better when upgrading.

Linear Force

The syringe pump exerts a force on the plunger to dispense or withdraw liquid from the syringe. When resistance is high, a greater force capacity helps ensure steady flow. High resistance can be caused by high flow rates like using a 150 mL syringe with very small inner diameter tubing or from liquids with high viscosity, like polymer solutions used in electrospinning or fiber extrusion. Additionally, high resistance can be caused by bubble formation or blockages in the tubing, syringe outlet, or microfluidic chip.

Blockages are common when working with polymer solutions, liquids with particles (like cells or microspheres), and microfluidic chips used for nano/microparticle synthesis. Rather than relying on a high linear force to ignore blockages, it is best to stop the system and remove the blockage before continuing with the experiment.

Usability and External Communication

Ease of use is mainly assessed after receiving and using the syringe pump but it can't be any harder than the red one, right?

External communication is important to consider if the pump will be integrated into automation or dispensing that requires feedback or remote control. If so, make sure the pump is equipped with RS232 and RS485 capabilities.

Upgrade to an ISPLab Series Syringe Pump

With all this being said, the ISPLab Series syringe pumps by DK Infusetek offer exceptional value for their price. We found the touchscreen easier to use over the SPLab's keypad and rotary knob. Below is a table comparing different dual-channel syringe pumps available today. The dual-channel red one is in the second column. But honestly, if you don't need to upgrade, the red one does the job for many applications.

And yes, if you see an unbranded DK Infusetek syringe pump, chances are it was made by DK Infusetek. Why pay more for one that is privately labeled?

About DK Infusetek

Baoding Shenchen Precision Pump Company, a popular pump manufacturer in China with 20+ years of delivering fluid handling solutions, branded their syringe pumps to DK Infusetek and their peristaltic pumps to Innofluid to better serve the global market. While North America has several syringe pump brands, these companies are less accessible in the global market. The price/performance ratio has made DK Infusetek a cost-effective choice for the global syringe pump market.