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Screw vacuum pumps

Our Products Operating principle
3d_animation_screw_outlet

Types of dry screw vacuum pumps

Busch offers two ranges of dry screw vacuum pumps:
COBRA Industry dry screw vacuum pumps are ideally suited for industrial applications requiring reliable and contaminant-free extraction of gases and vapors.

COBRA Semicon dry screw vacuum pumps are the ideal choice for all demanding processes in the production of photovoltaic cells, flat panel display production, semiconductors, and numerous industrial coating applications.

Product series
Nominal pumping speed
Type
COBRA NX
350 m³/h - 950 m³/h
Industry
COBRA NX PLUS
900 m³/h
Industry
COBRA NC
110 m³/h – 2,500 m³/h
Industry
COBRA NS
70 m³/h - 600 m³/h
Industry
COBRA NF
750 m³/h - 950 m³/h
Industry
COBRA DX
650 m³/h - 950 m³/h
Industry
COBRA BA
85 m³/h - 105 m³/h
Semicon
COBRA BC
100 m³/h – 1,580 m³/h
Semicon
COBRA DS
70 m³/h – 1,640 m³/h
Semicon

High-performance and robust vacuum generation for industrial applications

COBRA Industry COBRA Semicon

Applications

Dry screw vacuum pumps are used in a variety of industries. They are suitable for applications ranging from packaging to growing silicon crystals for solar panels.

Each industry and application has different needs. To find out which vacuum solution fits your needs best, get in touch with our Busch experts.

Find out more about how dry screw technology is used in different applications.

Your application is not mentioned? Check out our product finder!

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Vacuum systems building

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Self-adjusting cooling

Temperature independently balanced. The air condition for the pump. We invented it for you.

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FAQ

What is a dry screw vacuum pump?

A dry screw vacuum pump is a positive displacement pump that operates without oil. Two screw rotors rotate in opposite directions inside a cylindrical housing. The pumped medium enters via the inlet and is trapped and transported in chambers formed between the cylinder and the twin screws. Due to the rotation of the screws, the pumped medium is compressed and expelled via the outlet. No lubricants or operating fluids are required in the compression chamber. The minimal clearance between the screw rotors and the housing optimizes the internal seal.

The oil-free operation makes dry screw vacuum pumps ideal for applications requiring clean vacuum environments. They are used for various applications in industries ranging from lithium-ion battery production to vapor recovery.

How does a dry screw vacuum pump work?

Dry screw technology ensures high-performance and robust vacuum generation for industrial applications.

Inside dry screw vacuum pumps, two screw rotors rotate in opposite directions. The pumped medium is trapped between the cylinder and the screw chambers.

There, it is compressed and transported to the outlet. During this process, the screw rotors do not come in contact with each other or the cylinder.

Cooling is achieved through air or water cooling.

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    Illustration of screw technology

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    Illustration of screw technology

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Vacuum generation in dry screw vacuum pumps explained in three steps

1. Inlet

  • The pumped medium enters via the inlet.
  • Two screw rotors rotate in opposite directions inside the cylindrical housing.

2. Compression

  • The pumped medium is trapped and transported in chambers formed between the cylinder and the twin screws.
  • The chamber size continuously decreases, and the pumped medium is compressed.
  • During the compression process, the screw rotors do not come in contact with each other or the housing.

3. Outlet

  • After compression, the pumped medium is expelled through the outlet.
  • The use of a twin screw design ensures the shortest possible gas path between the pump inlet and outlet, resulting in a fast compression process and quicker cycle times.

  • 3d_animation_screw_inlet

    Inlet

  • 3d_animation_screw_compression

    Compression

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    Outlet

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    Inlet

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    Compression

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    Outlet

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Are dry screw vacuum pumps positive displacement pumps?

Yes, they are. A positive displacement pump is used to move and compress gas or air by repeatedly trapping a fixed volume of the pumped medium and moving it mechanically through a system. It maintains a constant flow and speed regardless of changes in pressure.

What are the differences between an oil-sealed screw vacuum pump and a dry screw vacuum pump?

In principle, oil-sealed screw vacuum pumps are just compressors that run the other way around. Therefore, they are not actual vacuum pumps but rather converted compressors.

What are the advantages and disadvantages of dry screw vacuum pumps?

Dry screw vacuum pumps from Busch are perfectly suited for demanding processes. They have several benefits:

  • Advanced screw design
  • Dry and contact-free operating principle
  • Highly energy-efficient
  • Low noise level
  • Compact dimensions

Vacuum pumps with this technology can be used for a large variety of applications, from chemical and pharmaceutical industries to packaging. However, they are not suitable for highly corrosive applications that require special alloys and coatings for housing and rotors.

How do I select the appropriate dry screw vacuum pump?

Several factors have to be considered when selecting the right vacuum solution. These factors vary depending on the application and the specific needs of your process.

Use our product finder to find your ideal vacuum pump. Or contact us to find out which vacuum solution fits your needs best. Our Busch experts are happy to help!

What makes Busch one of the leading manufacturers of dry screw vacuum pumps?

Busch has been improving dry screw vacuum technology for the past 30 years. With their patented self-balancing and self-draining screws, the dry screw vacuum pumps of the COBRA series set new standards in terms of efficiency. The design eliminates any risk of liquid accumulation inside the housing.

We offer different series types of dry screw vacuum pumps that enable us to provide the best solution for every application.