Dry, Clean, Flexible & Safe Vacuum

Our Dry Vacuum Pumps & Systems deliver dry, clean, flexible, and safe vacuum solutions. They are engineered for rigorous, non-stop demands of tough industrial environments; such as pharmaceutical and fine chemicals.

Dry Vacuum Pumps & Systems are one of the most reliable and highly efficient solutions on the market. Learn more about our dry product offering by clicking the cards below.

We provide a wide range of dry vacuum pumps packaged as bare pumps, pre-engineered or engineered-to-order systems. Engineered-to-order systems are custom designed to meet customer process requirements. Pre-engineered packages are available for quick shipment with plug & play installation.

Contact-Free Operation

Our dry vacuum pumps operate contact-free. This means they do not require lubrication in the pumping chamber. Therefore, our dry vacuum systems operate without water, oil, or any other liquid. This results in major advantages like no process contamination or pollution caused by the pump operation.

NASH dry vacuum pumps & systems offer significant process and economic benefits. Dry technology provides lower installation expenses, easier maintenance, low running costs, and reduced environmental impact while providing a more flexible vacuum. 

Designed To Handle Tough Industrial Applications 

Our dry screw vacuum pumps & systems deliver a clean, oil-free vacuum for a variety of industrial applications. In these applications, our pumps perform with low rotational speed ensuring smooth and robust operation. Higher discharge pressure capabilities along with a high tolerance for vapor and dust guarantee more process time with long service life.


Our dry vacuum pumps & systems safely and reliably handle corrosives, organics, inorganics, and solvents.  Thus, making NASH dry vacuum pumps & systems ideal for applications like degassing, vacuum metallurgy, vapor recovery, and central vacuum systems.

Since these applications require a clean, oil-free vacuum, our dry pumps serve the following market segments:

  • Chemical
  • Pharmaceutical
  • Industrial
  • Petrochemical
NASH Dry Vacuum Pumps & Systems


Furthermore, our dry vacuum pumps & systems have a wide operating range, low life-cycle costs, and long maintenance intervals. The wide operating range allows the pump to have limitless capacities with various backing pump options including high vacuum boosters.

NASH dry vacuum pumps operate from well below 0.1 torr up to atmospheric pressure. Low life-cycle costs and maintenance-free results in high efficiency and a reduction in energy and utility costs, as well as minimized operational downtime.

Dry Screw Vacuum Pump Principle of Operation

NASH Dry Screw Vacuum Pump
Dry Vacuum Pump
  • A dry screw vacuum pump consists of two parallel, non-contacting helical screw-shaped rotors (1) and (2). Fig. 1, rotating synchronously at high speeds via precision gears (3). They rotate in opposite directions. Therefore, trapping a quantity of gas at the inlet (5). Then, transporting it towards the exhaust port (6) and into the exhaust channel (7). The walls of the stator (9) and the special shape of the intermeshing screws form the compression chambers or pockets (4) that transport the gas.
  • Small clearances between the screws and the stator, as well as small clearances between the intermeshing screws, ensure that the amount of reverse leakage towards the inlet is small in comparison to the forward flow of gas generated by the screw pockets.
  • Reverse flow of the pumped gases is prevented by the length of the sealing boundary, (i.e., the number of spirals and tight clearances). On pumps fitted with a compression plate a slight reverse expansion of gas into the screws occurs when the outlet valve or port is first exposed. This is quickly expelled as the trapped volume is progressively reduced to zero by the action of the screws.
  • The reverse flow of gas is primarily controlled by the width of the “sealing lands” on the tips of the screw profile. These wide lands run in close proximity with the stator and minimize the reverse leakage of gas. Ultimate pressures in screw pumps can be less than 0.01 orr (0.01 mBar). 
  • In variable pitch models, the gas is compressed as the pitch changes to give additional compression before the pump exhaust. This spreads the heat load more evenly across the length of the rotors. In single pitch models, more compression is achieved in the last half-turn against a compression plate or valve, biasing the heat generation towards the exhaust. In dry pumps, temperatures have to be high enough to avoid condensation throughout and low enough to avoid auto-ignition and polymerization. Progressively higher gas temperature towards the exhaust in variable pitch pumps assists greatly in preventing condensation of pumped vapors. Variable pitch screw pumps also use power more efficiently than single pitch ones. 
  • Cooling is achieved via the surrounding jacket (8).  Pumps can be configured for direct or indirect closed-loop cooling. There are many advantages with the latter, as it means the plant’s cooling water is never in direct contact with the pump material and the jacket cannot silt up or corrode due to poor cooling water quality.
  • A gas ballast port (10) is available. If required, a gas ballast can help to warm-up a cold pump or dry a wet pump faster, take a flammable vapor out of its flammable range and help to clean solids out of a pump, particularly during solvent flushing. 

Do you want to learn more about the technology behind our dry screw vacuum pumps & systems Visit our technology page or watch the video below!


Dry Screw Vacuum Pump Technology

Watch our Animation to Learn how Dry Vacuum Pumps Deliver Contact-Free Operation

Quality Sustainable Solutions

All NASH equipment is fully assembled and tested prior to installation. This assures top quality and avoids issues or operational downtime. We are a global leader of highly engineered industrial, system critical vacuum solutions. 

Backed by over 110 years of experience, NASH CERTIFIED™ experts provide aftermarket support with maintenance, service, parts, and repair.

Our service centers are globally located to keep your systems operating and to protect your vacuum investment by providing quality, reliable and efficient solutions. 


FAQs About Dry Vacuum Pumps


Q: What is a dry vacuum pump?

A: A dry vacuum pump is a type of pump that operates without the need for liquids such as water or oil in the pumping chamber. This design feature ensures that the pump provides a clean, oil-free vacuum, making it ideal for applications where contamination must be avoided. Dry vacuum pumps often use two non-contacting, rotors to trap and transport gas from the inlet to the exhaust.

Q: Can vacuum pumps run dry?

A: While traditional vacuum pumps may require lubrication or fluid in the pumping mechanism to operate, dry vacuum pumps are specifically designed to run dry, without the need for any liquid in the process. This allows for a clean operation and reduces the risk of contaminating the process or environment.  While the pumps do require lubricants for the bearings and sometimes a fluid to cool the pump, neither are able to come in contact with the process gas. 

Q: Where are dry vacuum pumps used?

A: Dry vacuum pumps are versatile and are used in various industrial settings, including chemical, pharmaceutical, industrial, and petrochemical applications. They are particularly useful in processes such as degassing, vacuum metallurgy, vapor recovery, and central vacuum systems where a clean and oil-free vacuum is crucial.

Q: What are the benefits of a dry vacuum pump?

A: Dry vacuum pumps offer numerous advantages over traditional pumps that use fluids. Liquid sealed pumps typically have a waste stream of liquid that comes at a cost and usually requires treatment before disposal.  As the pumps do not need to drive a motive fluid, they require less electrical power and operate more efficiently.  Some benfits in addition to the reduced environmental impact include lower installation and operating costs, easier maintenance, and a longer service life. They also provide a flexible vacuum solution with the ability to handle corrosives, organics, inorganics, and solvents safely and reliably.


Downloads For Dry Vacuum Pumps & Systems