All You Need to Know About Vacuum Generators

An Ultimate Guide to Understanding the Vacuum Generator and its Working!


A vacuum generator provides the needed vacuum. There are two ways of generating a vacuum, pneumatically (ejectors) or electrically (pump and blower). The compact and lightweight design of pneumatic vacuum generators allow them to be integrated directly into systems with short cycle times. Ejectors are capable of controlling energy and process. It is often necessary to use electrical vacuum generators when there is no compressed air available or where high suction capacities are required.

What is a Vacuum Generator?

Sub-atmospheric pressure is provided by vacuum generator for a number of manufacturing and scientific uses. In the disciplines of chemical and semiconductor processing, vacuum pump technologies are employed for commercial gripping and chucking, laboratory degassing, and purification. Many different businesses, including the pharmaceutical, food processing, and agricultural sectors, use vacuum handling devices.


A vessel or space that has substantially lower gas pressure than the surrounding atmosphere is said to be in a vacuum. The force of flowing gas molecules slamming into a vessel's walls produces pressure. In short, eliminating gas molecules (matter) from the container reduces the frequency of collisions, which lowers the pressure. This is how a vacuum is created in a container.


How closely the pressure resembles an ideal vacuum is referred to as a vacuum's quality (zero pressure). Ranges of pressures that are specified based on either a "Classic" approach or the American Vacuum Society are used to describe vacuum quality.

Types of Vacuum Generators

The vacuum generators can be broadly categorized as follows:

  1. Pneumatic Vacuum Generators
  2. Electric Vacuum Generators


Let’s dig deeper into the details of both types of vacuum generators to better understand these vacuum generators:

  1. Pneumatic Vacuum Generator/ Vacuum Ejectors

The vacuum is produced by a pneumatically powered nozzle, which is created by pneumatic vacuum generators, also referred to as vacuum ejectors. They are appropriate if the application needs quick turnaround times. Due to their small size and lightweight, they can be integrated right into the system. They are classified as single-stage, multi-stage, and compact vacuum generators based on the number of nozzle pairs. The Venturi effect is the basis for how the vacuum generator works.


  • Single-stage Vacuum Generators

A jet spray or a Venturi nozzle through which pressurized air is passed makes up a single-stage vacuum generator. The air speeds up as the jet nozzle gets smaller. A vacuum is produced at the enlarged side when it expands as it moves past the narrow nozzle. The intake draws in air, while the silencer allows compressed air to leave the system.


  • Multi-stage Vacuum Generators

A row of several Venturi nozzles forms a multi-stage vacuum generator. The connecting port is used to supply compressed air. Several Venturi nozzles process this compressed air. The air is sucked through the inlet as the vacuum is formed. The sum of the suction from each generator nozzle is the average suction rate at the inlet. In comparison to single-stage vacuum generators, multi-stage vacuum generators may produce a significantly higher suction rate using the same volume of compressed air.


  • Compact Vacuum Generators

The compact vacuum generators contain technologies for system monitoring and valve integration. Without using an external valve, this generator makes it simpler to regulate the pick-up and blow-off. They are typically employed in handling fully automated systems.


  1. Electric Vacuum Generators / Vacuum Pumps

The application of electric vacuum generators, commonly referred to as vacuum pumps, occurs when a large suction capacity is necessary or when compressed air is not readily available. The vacuum pump functions by expelling air molecules from the vacuum chamber. It comprises of a carbon-bladed rotary impeller that is eccentrically installed. The centrifugal force pushes the impeller up against the housing wall, creating a tight seal.


With the impeller's rotation, the dimensions of each chamber alter. The air inside the compartment expands as the chamber enlarges. As a result, there is a fractional vacuum in the chamber as the pressure decreases. This process draws in the air, compresses it, and then pushes it out of the outlet. The vacuum pump can produce a high vacuum and have a large suction capacity thanks to the high compression factor.


So, How Do Vacuum Generators Work?

The single-stage generator circulates air through a conical Venturi aperture in its most basic configuration. The pressure decreases and the velocity rises as the compressed air moves away from the conical aperture restriction and into the wider open lines. The strength is such that a vacuum is created (lower pressure than the surrounding air pressure), which draws the air that has to be expelled from the system into the moving airstream and blows it out.


Compressed air is used in single-stage vacuum generators by speeding it down a restrictor tube to produce a Venturi effect, which ejects the necessary amount of air. Since their fundamental design is geared to meet either the highest flow or maximum evacuation volume requirement, these single-stage Venturi generators are rather constrained in their ability to match numerous applications effectively.


There is a common rule of thumb that this type of vacuum generator utilizes compressed air at a ratio of no better than 1:1, but sometimes as high as 2 or 3.


For several applications, multi-stage vacuum generators are created to increase this performance. The multi-stage machines employ a number of ejectors and nozzles to provide controlled expansion of compressed air in stages. By doing this, the ratio of compressed air usage to vacuum flow is typically increased to 1:3 or better.


Multi-stage systems can create a vacuum at lower pressure and are also noticeably quieter. This performance will lessen the amount of compressed air that is needed under the same circumstances, as well as speed up reactions and boost output.


Advantages of a Vacuum Generator

A few benefits of the vacuum generator include:

  • No Vibration at all
  • No heat is produced
  • No Moving Parts
  • With the air supply, the vacuum is instantaneously turned on and off.
  • Very well tolerates tough circumstances
  • Cheap
  • Rapid replacement or repair
  • Located relatively close to the process, they can enable quicker cycle times and less air evacuation.
  • Portable and light
  • No electricity is necessary.
  • Short turnaround time for service and/or component replacement



Vacuum generators are regarded as practical, adaptable solutions with quick responses. For many localised operations, choosing the most energy-efficient products might be challenging due to the extensive product development.


If you are facing any difficulty in the selection of vacuum generator, head on to CHELIC and get a vacuum generator of your relevant needs.


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FAX : 886-2-29068203

No.21, Guifeng St., Taishan Dist., New Taipei City 243, Taiwan

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