Vacuum ejector: what it is, types, applications

A vacuum ejector is a device that uses a rapid flow of air, steam, or water to create an area of low pressure (vacuum). This is similar to how water from a hose creates a suction effect when passing through a narrow opening. This force can lift or move other liquids or gases.

Vacuum ejector device

There are several key components in a vacuum ejector. Each of them is simple but important for its functioning. The main parts of a vacuum ejector are:

• The ejector body is made of metal: steel, stainless steel, aluminum, or other durable materials. It directs fluid flows and maintains the structural integrity of the device.
• The working fluid passes through the nozzle. It has a narrow section where the fluid velocity increases and a low-pressure zone is created.
• The diffuser is located after the nozzle and helps to stabilize the flow and improve the efficiency of vacuum creation.
• The mixing section is the area where the working fluid mixes with the gas or vapor being extracted.
• The inlet pipe is designed to supply compressed air, steam, or liquid to the ejector.
• The inlet pipe for the extracted fluid is connected to the system from which the gas or vapor needs to be removed. It directs the fluid into the mixing section.
• The outlet pipe removes the mixed flow of working and extracted fluid from the ejector.

The design of a vacuum ejector may vary depending on its application and the type of working fluid used. This affects the suction power and operating time. Therefore, different models of ejectors have been developed for different tasks.

Types of vacuum ejectors

All ejectors operate on a similar principle. What differs is the forces used to create the vacuum. Ejectors also use different media as the fluid. The main types of ejectors are:

• Pneumatic ejectors operate on compressed air. They are often used in industry due to their simple design and lack of moving parts.
• Steam ejectors operate on steam.
• Liquid ejectors operate on liquid, usually water. They are installed in systems where a vacuum needs to be created at minimal cost.

Multi-stage ejectors consist of several ejectors connected in series. They create a stronger vacuum than single-stage devices. They have higher suction power and are capable of operating for long periods of time.

Application of vacuum ejectors

Ejectors are used in many areas, including industry, manufacturing, and equipment. Examples of where vacuum ejectors are installed:

• In industry, vacuum ejectors are needed for vacuum forming, packaging, and lamination.
• In medicine, vacuum systems are used in surgical systems to remove fluids.
• In the chemical industry, ejectors are needed to maintain low pressure in rectification columns.
• In the energy sector, vacuum ejectors remove non-condensable gases from condensers at power plants.
• In the automotive industry, ejectors are used for vacuum casting of plastics and metals. They are installed in brake systems to create a vacuum.

Vacuum ejectors are versatile. Therefore, they are used in various industries and medicine. They are reliable, simple in design, and effective. The choice of ejector type depends on the vacuum quality requirements and operating conditions.