Ejektorer

Ejektorer, also known as ejectors or steam ejectors, are devices that utilize the kinetic energy of a fluid jet to entrain and compress another fluid. They are a type of jet pump and operate on the principle of Bernoulli's equation. A high-pressure motive fluid, typically steam or a liquid, is accelerated through a nozzle, creating a low-pressure zone. This suction effect draws in a secondary fluid, which is then mixed with the motive fluid and compressed in a diffuser section. The diffuser converts the kinetic energy of the combined fluid stream into pressure energy, resulting in an increased pressure of the entrained fluid.

Ejektorer are commonly used for creating vacuum, pumping liquids, and mixing gases. Their simplicity, lack of moving parts, and reliability make them suitable for a wide range of industrial applications. They can handle corrosive or abrasive fluids and operate under extreme temperatures. Common uses include vacuum generation in distillation processes, chemical reactors, and vacuum packaging. They are also employed in refrigeration systems, vacuum distillation, and for pumping liquids in chemical plants.

The performance of an ejector is characterized by its entrainment ratio, which is the ratio of the mass flow rate of the entrained fluid to the mass flow rate of the motive fluid. This ratio is influenced by factors such as the motive fluid pressure, entrained fluid pressure, and the geometry of the ejector. While simple and robust, ejectors are generally less efficient than mechanical pumps, particularly at high compression ratios. However, their cost-effectiveness and ability to operate without mechanical wear make them a preferred choice in many specific scenarios.