Pipettes are slender tubes that measure or transfer small quantities of liquid. They’re widely used throughout the pharma and biotech industries in diagnostic laboratories.
Today, medical laboratories around the globe are automating more of their processes. This trend enables healthcare providers to test & diagnose a wider range of conditions in the hospital or the doctor’s office, as opposed to sending tests out to remote labs. This facilitates quicker diagnosis and earlier detection for health conditions. But this level of automation also requires faster and more precise equipment.
How do Pipettes Work?
Pipettes work much like a syringe. They create a vacuum that draws liquid into the pipette, and they disperse a precise amount each time. Pipettes come in a variety of sizes, ranging in volume from a few micro-liters to several hundred milliliters. Pipettes are typically used in sterile environments, so preventing cross contamination is essential. Immunity Automatic Workstations use a large number of Electronic Pipettes, and these systems feature cams, pistons and cylinders.
Several of the world’ largest diagnostic labs use HKP technology to power their Immunity Automatic Workstations. Different options exist to provide machine designers with flexibility to make these workstations smaller, faster and more precise.
Application Requirements:
- Accuracy and Repeatability: Electronic pipettes can dispense specific volumes of liquid with great precision. Pipette resolution is generally 1 microliter per increment, with an error of less than 1%. Equally important is repeatability, ensuring that the exact same volume of liquid is extracted or distributed in each subsequent operation.
- Cost Savings: The ability to enhance accuracy enables labs to use fewer reagents in their analysis, which reduces costs.
- Efficiency & Ergonomics: Electronic pipettes require less physical movement. Once the electronic straws are set up, users can fill, empty and eject them with the click of a button. This increases productivity and it boosts the number of samples that can be processed in a given time.
Application Challenges
- Accuracy and repeatability: Pipettes typically have a resolution of 1 microliter per increment, with an inaccuracy below 1%.
- The space between multi-channel Pipettes is very small. It requires a motor diameter that is less than 16mm, and the
length is generally less than 100mm.
- Thrust must be greater than 8N, and speed must exceed 8mm/s
- Noise and vibration must be minimized
Selection criteria for motors typically includes size, performance, price and efficiency. Most engineers choose between cost-effective linear step products, or small size brushless motors.
Stepper Motor:
Linear Stepper Motors are off-the-shelf solutions that are suitable for electronic pipetting applications. The built-in lead screw connects directly to the piston of the electronic pipette to provide the linear motion required to operate the device. Also, since it is a stepper, no additional feedback sensors or encoders are required to control the motor. The stepper motor rotates incrementally with each current pulse, making it easy to control. The linear stroke accuracy of the motor, as well as the possibility of micro-stepping, provides a very high resolution – which is matched by the high requirements for precision and repeatability of electronic pipettes. In addition, the motor can hold its position without a power supply, thus extending the range of use of the device. Linear Stepper Motors are typically used for output speeds below 800 RPM.
Stepper Motor with RGS Linear Rail:
The RGS is a screw-driven rail system that offers exceptional linear speed, accurate positioning, a narrow base and long life in a compact, value-priced assembly. The length and speed of the RGS is not limited by critical screw speed, allowing high RPM and linear speeds, even over long spans.
- Many optional leads are available in inch or metric
- Available in custom lengths > 2.4m
- All moving surfaces include Kerkite® polymers running on Kerkote® TFE coating
- Available in guide only, lead-screw driven, motorized and motorized with integrated driver.
Brushless Motors:
An alternative to the Linear Stepper Motor is a coreless, brushless DC motor. This option is the most efficient technique, as the rotor consists solely of a coil and shaft (as opposed to an iron-core motor). As a result, the coreless motor does not have any iron damage, which improves the efficiency and acceleration of the motor. Since the electronic pipettes are powered by batteries, the increase in efficiency results in longer use times on a single charge.
The brushless product has a diameter of 13mm and is equipped with a small size encoder, gearbox and lead screw. The speed can work at 60,00 RPM, and the excellent output power is conducive to use in small spaces.
For pipetting applications, brush DC and BLDC motors require additional components, such as belt drivers and encoders, for converting rotary motion to linear motion and for controlling the motor. This solution is typically used in higher-end models, with multiple channels.
Current and Future Market Trends:
The trend towards conducting more testing & diagnostics directly in local doctor’s offices is driving the demand for Immunity Automatic Workstations, electronic pipettes, and the motion solutions that power them.
In China alone, the pipette industry is growing by more than 7% per year. A recent Chinese Serum Pipette Industry Market Report sizes the 2023 pipette industry at 867 million yuan, and forecasts growth in China to reach 1.35 billion yuan by 2025.
For more information on Pittman Motion Solution for Immunity Automatic Workstations and electronic pipettes contact us today.
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