The principle of Venturi Injector is a vacuum obtaining device that uses fluid to transfer energy and mass. The water flow with a certain pressure is sprayed through the nozzles symmetrically and evenly distributed with a certain side inclination, and converges on a focus. The Venturi Injector manufacturer tells you that due to the extremely high flow rate of the injected water, the pressure energy is converted into velocity energy, and the pressure in the suction area is reduced to generate a vacuum. Several high-speed water streams will snatch the pumped gas, and fully mix and compress through the constricted section of the venturi and the throat diameter, and carry out molecular diffusion energy exchange with balanced speed. The manufacturer of Venturi Injector tells you that when the speed of the expansion section decreases, the pressure increases, and the pressure is greater than the atmospheric pressure, which is sprayed into the water storage tank (pool) from the outlet, and the non-condensable gas is released. The water is recycled through the centrifugal pump to complete the suction process.

Such a device is called a Venturi Injector, in which two fluids of different pressures mix with each other and exchange energy to form a mixed fluid at an intermediate pressure. The mixed fluid is divided into gas (vapor) phase, liquid phase, or a mixture of gas (vapor), liquid and solid. Before entering the device, the medium with higher pressure is called the working medium. The working medium flow is called working fluid. The working fluid exits the nozzle at a high velocity, enters the receiving chamber of the Venturi Injector, and carries away the lower pressure medium in front of the Venturi Injector. The entrained fluid is called the ejected fluid. Usually in a Venturi Injector, the conversion of potential or thermal energy of the working fluid into kinetic energy initially occurs. Part of the kinetic energy of the working fluid is transferred to the ejecting fluid. In the process of flowing along the Venturi Injector, the velocity of the mixed fluid gradually equalizes, and the kinetic energy of the mixed fluid is converted into potential energy or thermal energy instead.​​
The working medium fluid and the ejecting medium fluid enter the mixing chamber for equalization of velocity, usually accompanied by an increase in pressure. As the fluid comes out of the mixing chamber into the diffuser, the pressure will continue to rise. At the diffuser outlet, the pressure of the mixed fluid is higher than the pressure of the ejected fluid when entering the receiving chamber. Raising the pressure of the ejected fluid without directly consuming mechanical energy is the main performance of the Venturi Injector.​​
Due to this nature, in many technical sectors, the use of Venturi Injector makes it possible to obtain simpler and more reliable technical solutions than the use of mechanical booster equipment (compressors, pumps, blowers, induced draft fans, etc.). In addition to its very simple structure, the system for connecting Venturi Injector to various equipment is also very simple, and the manufacturing is not complicated, so it can be widely used in engineering. Among them, in the field of power engineering technology, it is mainly used for power generation, waste heat heating device, refrigeration, transportation of solid granular objects, etc.