Diaphragm Vacuum Pump

Reliable diaphragm vacuum pumps designed for efficient, oil-free vacuum solutions
in laboratory and industrial applications.


A diaphragm vacuum pump serves as a pivotal solution for generating vacuum without oil, catering to diverse medical, lab, and industrial applications. Welch's comprehensive portfolio encompasses standard pumps, specialized chemistry pumps, GEMINI environmental monitoring pumps, laboratory vacuum systems, and Univac systems. Engineered to meet industry needs, each pump type ensures efficiency and reliability, as well as clean operation and low maintenance (oil-free). Explore the Welch diaphragm vacuum pump range and experience vacuum technology innovation firsthand – ultimate vacuum from 75 to 1 mbar (56.25 to 0.75 Torr) and peak flow rates up to 138 l/min (4.87 CFM). 

What is a Diaphragm Vacuum Pump? 

A diaphragm vacuum pump is an innovative solution that generates vacuum without requiring oil. This advanced technology operates by harnessing the oscillations of a flexible diaphragm, which in turn creates fluctuations in pressure, ultimately inducing a vacuum. As the diaphragm undergoes flexion, it cyclically modifies the volume within the pump chamber. This process leads to the expulsion of air molecules from the chamber, culminating in the creation of a vacuum environment. Welch has specialized in developing diaphragm pumps characterized by their efficiency, reliability, and eco-friendliness. 


Where Are Diaphragm Vacuum Pumps Required? 

Diaphragm vacuum pumps find their place across a multitude of industries, offering versatile and reliable vacuum solutions that cater to diverse needs: 

  • Medical Precision: Diaphragm vacuum pumps maintain sterile fluid purity in critical medical procedures like blood collection and IV bag filling.
  • Laboratory Excellence: Diaphragm pumps support analytical instruments like gas chromatography and mass spectrometry, ensuring accurate sample analysis. Also, researchers rely on them for filtration, degassing, and precise experimental setups.
  • Pharmaceutical Precision: Diaphragm pumps facilitate botanical extractions, separating compounds for high-quality medicinal extracts. In addition, they contribute to pharmaceutical manufacturing, ensuring purity and quality throughout production.
  • Industrial Efficiency: Employed in the chemical industry for solvent recovery, enhancing resource efficiency. They are also used in other industries such as food, cosmetics, and textiles, ensuring reliable vacuum conditions for efficient production.
  • Biotechnology Advancements: In bioprocessing, diaphragm pumps support bioreactors, cultivating cells for biopharmaceuticals and vaccines.
  • Environmental Insight: Essential in environmental analysis, aiding accurate measurement of pollutants and contaminants.
  • Manufacturing Precision: They contribute to precision manufacturing processes, like solder paste printing.
  • Automotive Engineering: Used for inflating airbags during manufacturing, showcasing efficient vacuum generation. 

What Are the Advantages of a Diaphragm Vacuum Pump? How Does An Oil-Free Operation Benefit Users? 

The advantages of diaphragm vacuum pumps extend beyond traditional vacuum solutions. Welch pumps are engineered to provide oil-free operation, eliminating the risk of oil contamination in vacuum processes. This feature is especially crucial in industries where product purity is paramount. 

Welch’s diaphragm vacuum pumps work completely without oil, offering a range of benefits for users: 

  • Clean Operation (Oil-Free): Diaphragm pumps create a contamination-free vacuum environment by operating without oil, ensuring uncontaminated samples and eliminating the risk of oil back-streaming. 

  • Low Cost of Ownership: The absence of oil reduces maintenance requirements significantly, leading to cost savings and increased uptime. 

  • High Reliability: Welch's precision engineering guarantees consistent and reliable pump performance, meeting the demanding requirements of modern industries. 

  • Dry Vacuum: Diaphragm pumps create a dry vacuum, contributing to a cleaner workplace and environment by preventing oil emissions and associated hazards. 

  • Enhanced Sample Integrity: Uncontaminated pumping of gases ensures cleaner samples, making diaphragm pumps a suitable choice for applications requiring high sample integrity. 


How Does a Diaphragm Vacuum Pump Work? 

The core of a diaphragm vacuum pump's operation lies in the rhythmic movement of its diaphragm. This diaphragm, typically composed of a flexible material, acts as a barrier between the vacuum chamber and the external environment. As the diaphragm flexes, it creates changes in volume within the chamber, leading to alternating cycles of compression and expansion. During compression, air is expelled from the chamber, creating a region of lower pressure. This pressure difference facilitates the movement of gases from an area of higher pressure to the low-pressure region, effectively creating a vacuum. Welch's expertise in diaphragm pump technology ensures optimized diaphragm design, enabling precise and efficient vacuum generation. 


What Is the Pressure Range for a Diaphragm Vacuum Pump? Can Diaphragm Vacuum Pumps Achieve Deep Vacuum Levels?  

Diaphragm vacuum pumps are known for their versatility in achieving a wide range of vacuum levels, catering to various applications. While they may not reach the ultra-high vacuum levels attainable by some specialized pumps, diaphragm pumps excel in the mid to low vacuum range: 

  • Standard Duty Diaphragm Pumps (MP): These pumps typically achieve vacuum levels in the range of 70 to 150 mbar. They are well-suited for general laboratory tasks such as solvent filtration and sample preparation. 

  • Chemistry Diaphragm Pumps (MPC) and GEMINI Environmental Monitoring Pumps: Similar to standard pumps, MPC pumps offer vacuum levels in the same range of 70 to 150 mbar, with applications in sensitive chemical processes (chemical/MPC pumps) or demanding applications like gas sampling (GEMINI). 

  • Laboratory Vacuum Systems (LVS): LVS systems can achieve slightly deeper vacuum levels, often around 20 to 70 mbar. This range supports more advanced laboratory applications like rotary evaporation and gel drying. 

  • Univac Laboratory Vacuum Systems (MPKC): Univac systems, tailored for research, can achieve vacuum levels as low as 0.5 to 20 mbar. While not in the ultra-high vacuum range, they are suitable for a broad array of advanced experiments. 


Are Diaphragm Vacuum Pumps Suitable for Corrosive or Aggressive Gases?  

Diaphragm vacuum pumps can handle a variety of gases, including mildly corrosive ones, due to their chemically resistant materials. However, when dealing with highly corrosive or aggressive gases: 

  • Opt for pumps with PTFE diaphragms and seals for enhanced chemical resistance. 

  • Ensure proper ventilation and exhaust management to prevent harmful gas release. 

  • Regularly inspect and maintain the pump's components, replacing any damaged parts promptly. 

  • Consult the manufacturer for specific guidance on handling corrosive gases and follow their recommendations. 

By taking these precautions, diaphragm vacuum pumps can effectively handle corrosive gases while maintaining performance and safety.