Working principle of steam ejector

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Working principle of steam ejector: A steam ejector is a device that uses steam as power to meet engineering requirements. It does not require electricity, has no moving or rotating parts, features a simple design, and operates reliably, which is why it is widely used. 1. Working principle: The steam ejector converts the potential energy of high-pressure steam into high-speed kinetic energy through the nozzle; this drives in low-pressure steam, enabling thorough mixing within the ejector’s mixing section. As a result, the velocity of the steam decreases while its pressure increases, meeting the requirements of production processes. II. Structure Introduction: The structure of the injector consists of two main parts: 1. Nozzle: High-pressure steam forms a high-speed jet through the nozzle. The shape and size of the nozzle are determined based on the properties of the steam (superheated steam or saturated steam) as well as the pressure drop across the nozzle; the pressure drop across the nozzle should be 45.5% or more of the initial pressure for superheated steam. The saturated vapor is over 42.3% of the initial pressure. The nozzle is designed as a Laval nozzle; otherwise, it is conical in shape. The material used is 1Cr18Ni9Ti. 2. Injector mixing section: High-pressure and low-pressure steam enter this tube first, where they are mixed evenly before the pressure increases and the velocity decreases. Therefore, the mixing section consists of three parts: front, middle, and rear, each with a different function. With different shapes, their dimensions (diameter and length) are determined based on the total flow rate, in order to ultimately produce steam at the desired pressure. The component that connects the two is called a steam chamber, which keeps the two parts at an appropriate distance and provides a certain amount of space. The material commonly used for steam ejectors is high-quality carbon steel grade 20#. 3. Scope of application: 1. Steam jet booster: High-temperature and high-pressure steam with high energy is ejected at high speed through nozzles to draw in low-pressure steam, thereby mixing them to produce (medium-pressure) steam at the temperature and pressure required for industrial processes. This is a more energy-efficient approach to meeting process requirements (compared to temperature-reducing pressure regulators), and it is also more convenient. A device called a secondary steam recycler also falls into this category. 2. Steam jet water heater: It uses a steam jet to draw in a certain amount of cold water, heats it to the desired temperature, and delivers it to where it is needed; it can be used for heating and domestic water use. 3. Steam jet vacuum pump: It extracts the air from within the container using a steam jet, thereby creating a certain level of vacuum in the container. Such as the turbine shaft seal extractor, which prevents steam from leaking out of the turbine and recovers heat and working fluid. Another example is using vacuum creation in the suction section of a large circulating water pump to draw in water from a lower level.