preface
Heroes are made by the times, and technology drives change. Going back to the 1830s, Scottish inventor Robert Anderson created the first non-rechargeable electric carriage. However, due to limitations in battery life and motor control technology, the engine was switched to a steam piston principle. Similarly，based on the steam piston principle, piston pump technology emerged and gave rise to industry leaders such as Scheugenpflug，Huebers from Germany, and NLC from Japan. These companies have established a leading position in the market by leveraging piston pump technology.
As time progressed and technology rapidly advanced, motor technology evolved from the AC motor in 1873, through the stepper motor in 1970, to modern servo motors. Each technological update and transformation brought new possibilities for pump control methods. Entering the 20th century, the rise of high-precision screw pump metering technology brought unprecedented efficiency and accuracy to industrial production and quality control. In this new era, a number of companies specializing in high-precision screw pumps have emerged both domestically and internationally. Notable examples include Germany's ViscoTec (founded in 1997, primarily focusing on pumps for the food, pharmaceutical, and chemical industries), Bdtronic, and American companies PVA and Nordson, as well as China's XETAR.
Next, we will delve into the working principles, structures, performance, and characteristics of piston pumps and screw pumps. We will also examine their performance in handling high-viscosity adhesives containing solid particles. Through the analysis of specific industrial cases, we will reveal the excellent performance of screw pumps in the new era and their significant effects in practical applications.
Ⅰ. piston pump
1.1 Working principle of piston pump
The working principle of a piston pump is to compress and transport liquid or gas through the movement of a piston. Its working principle is as follows:
Metering Process: Feeding → Metering → Retracting → Cycling
The piston moves back and forth through a fixed cylinder liner and seals, with the seals installed on the cylinder body.
The plunger performs a reciprocating motion within the pump cylinder liner, causing a change in the volume between the plunger and the cylinder liner. This results in periodic changes in the working volume of the pump chamber, allowing for the repeated suction and discharge of liquid while increasing its pressure.
A reciprocating piston pump relies on the back-and-forth motion of the piston within the pump cylinder to cyclically expand and contract the working volume of the pump cylinder, thereby sucking in and discharging liquid. It has self-priming capabilities and can maintain nearly constant flow even under significant pressure changes. This makes it particularly suitable for transporting highly viscous liquids in scenarios with small flow rates and high heads. However, when transporting high-viscosity liquids or adhesives containing solid fillers, the adhesive can easily precipitate and stratify within the piston chamber. Solid fillers tend to deposit at the bottom of the piston chamber, leading to pump jamming and other malfunctions.