The RPP Series is Zhongtian's corrosion-resistant water jet vacuum pump range, designed for chemical, pharmaceutical and industrial process applications requiring oil-free vacuum generation and compatibility with suitable corrosive media. Vacuum is generated by a high-velocity water jet rather than mechanical displacement, leaving the ejector itself free of rotating or reciprocating pumping components. With pumping capacities from 20 to 700 m³/h and an ultimate pressure of 2000 Pa under specified test conditions, the RPP Series provides a simple and robust vacuum solution for compatible corrosive, wet-gas and condensable-vapour applications. Complete systems can be configured with circulation tanks, centrifugal pumps, gas-liquid separation, cooling and control equipment according to process requirements.
Working Principle
The RPP Series operates on the liquid-jet ejector principle. Pressurized operating water supplied by the centrifugal pump enters the ejector nozzle, where pressure energy is converted into kinetic energy and a high-velocity water jet is formed. The high-velocity jet creates a low-pressure region around the suction chamber, drawing process gas into the ejector. The entrained gas mixes with the operating water in the mixing section. The gas-liquid mixture then passes through the diffuser, where velocity is reduced and part of the kinetic energy is converted back into pressure. The mixture is discharged into the circulation tank, where non-condensable gas separates from the operating water. The water is then returned to the centrifugal pump for recirculation. Because the pumped gas comes into direct contact with the operating water, gas-liquid compatibility and downstream wastewater or recovery requirements should be considered during system selection.
Key Features
No Mechanical Moving Parts in the Ejector
Vacuum generation in the RPP ejector is achieved by fluid-energy conversion rather than mechanical displacement. The ejector itself contains no rotating or reciprocating pumping components, simplifying the vacuum-generating section and reducing the number of mechanically wearing parts exposed to the process gas. Note: The complete RPP system includes a centrifugal water pump with rotating components.
Oil-Free Vacuum Generation
The RPP Series uses water as the operating medium and does not require lubricating oil in the vacuum-generating ejector. This avoids contamination of the process gas by vacuum-pump lubricating oil and makes the system suitable for compatible process applications where oil contamination is undesirable. Note: Process gas comes into direct contact with the operating water in the ejector.
Corrosion-Resistant Construction
The RPP Series uses corrosion-resistant non-metallic construction for the ejector and process-contacting components, making it suitable for many compatible chemical and corrosive process applications. Material compatibility must be confirmed according to the process gas, liquid composition, concentration, temperature and operating conditions. Suitable for compatible process gases subject to material and temperature limits.
Water Recirculation System
After gas-liquid separation, operating water can be returned to the centrifugal pump for recirculation. Depending on the process, the circulation system may require cooling, make-up water, filtration or liquid treatment to maintain stable vacuum performance. Vacuum performance is strongly influenced by operating-water temperature. Lower water temperature generally improves achievable vacuum, while higher water temperature may reduce ultimate vacuum performance.
Complete RPP Vacuum System
The RPP Series can be supplied as a complete skid-mounted water-jet vacuum system including ejector, circulation tank, centrifugal pump, piping and related accessories. System configuration can be adapted to process requirements including gas-liquid separation, cooling, make-up water supply, filtration and control equipment.
*Performance values are based on specified test conditions: air temperature 20°C, inlet-water temperature 15°C, discharge pressure 1013 hPa, air relative humidity 70%. Actual pumping performance and ultimate pressure may vary with operating-water temperature, circulation-water conditions, gas composition and system configuration.
*Pumping-speed tolerance: ±10%.
*Pump Power refers to the centrifugal circulation pump power. The RPP ejector itself has no drive motor.
Typical Applications
Vacuum distillation, evaporation, crystallization and compatible corrosive process vacuum
Vacuum concentration, drying and compatible process applications
Filtration and process vacuum involving compatible corrosive media
Vacuum-assisted condensation and recovery of compatible process vapours
Vacuum-assisted gas collection, absorption and compatible waste-gas treatment
Oil-free vacuum generation for compatible corrosive gas applications