The Roots water jet vacuum unit is a device that uses water as the working medium and extracts vacuum through principles such as the Venturi effect. The core component is a water jet pump, mainly composed of a nozzle, a suction chamber, a diffusion chamber, and other parts.

When a certain pressure of water (working water) passes through the nozzle of the water jet pump, due to the tapered structure of the nozzle, the water flow velocity rapidly increases, and the pressure energy is converted into kinetic energy. According to the Bernoulli equation, as the flow velocity increases, the pressure of the water flow drops sharply, forming a high-speed jet at the nozzle outlet and creating a low-pressure area around it. This low-pressure area is connected to the pumped container (such as a vacuum tank, reaction kettle, etc.), and the gas inside the container is sucked into the suction chamber under the action of pressure difference, and mixed with the working water of high-speed jet.

The mixed air-water mixture enters the diffusion chamber. In the diffusion chamber, as the flow cross-section gradually expands, the velocity of the airflow gradually decreases, and the kinetic energy is converted into pressure energy, causing the pressure of the air-water mixture to rise. Then, the air-water mixture is passed through subsequent separation devices such as condensers and separators. In the condenser, water vapor is cooled and condensed into water, while uncondensed gases (mainly non condensable gases) are discharged from the system through a separator. And a part of the condensed water is used as circulating water to return to the water jet pump for continued use, while the other part is discharged as drainage to maintain the water balance of the system.

Throughout the process, the amount and pressure of working water are maintained by continuously replenishing fresh water, ensuring the continuous and stable operation of the Roots water jet vacuum unit, thereby forming and maintaining a certain degree of vacuum in the container being pumped.

Advantages of Roots water jet vacuum unit:

（1） Simple and compact structure

The main components are relatively few, and the structural design is relatively simple. Without complex mechanical transmission components such as rotating impellers, the manufacturing and maintenance costs of the equipment are relatively low. At the same time, a simple structure also means that it occupies less space, is easy to install, and can adapt to various working environments and site conditions.

（2） No oil pollution

Compared with traditional vacuum pumps, using water as the working medium does not produce oil mist pollution. This is particularly important in industries that require high levels of cleanliness, such as food, pharmaceuticals, and chemicals. It can avoid the impact of oil pollution on product quality, ensuring the purity and safety of the production process.

（3） Capable of handling corrosive gases

Due to the working medium being water, it has a certain tolerance to gases containing corrosive components. For example, in some chemical production processes, acidic or alkaline gases are generated. The Roots water jet vacuum unit can effectively extract these gases without severe corrosion, extending the service life of the equipment.