Vacuum Systems
Closed-Loop Liquid Ring Vacuum Systems
Integrated Liquid Ring Vacuum Systems with Working-Liquid Recirculation
System Overview
Zhongtian Closed-Loop Liquid Ring Vacuum Systems integrate liquid ring vacuum pumps with gas-liquid separation, working-liquid recirculation, heat exchange, instrumentation and control equipment into complete process-vacuum solutions.
The operating liquid discharged from the vacuum pump is separated from the process gas, cooled through a heat exchanger and returned to the pump for recirculation. This arrangement significantly reduces fresh-water consumption and wastewater discharge while maintaining controlled operating-liquid temperature for stable vacuum performance.
Depending on the process, systems can be configured with condensers, condensate collection, corrosion-resistant materials, multi-pump redundancy, PLC control and other auxiliary equipment.
Each system is custom engineered according to the required pumping capacity, operating pressure, gas composition, vapour load, working-liquid properties and site utility conditions.
Key System Features
How the System Works
During operation, process gas enters the liquid ring vacuum pump and is compressed together with part of the circulating operating liquid.
The gas-liquid mixture discharged from the pump enters a separator, where the gas phase is separated from the operating liquid.
The separated gas can be discharged to atmosphere where appropriate, routed to downstream treatment equipment, or sent to a condenser or recovery system according to the process requirements.
The separated operating liquid is returned through the circulation loop. A heat exchanger removes heat generated by gas compression, incoming process gas and condensation of compatible vapours before the liquid returns to the vacuum pump. By controlling operating-liquid temperature, level and circulation conditions, the system maintains stable operating conditions for the liquid ring vacuum pump.
Gas Flow Path
Working-Liquid Recirculation
Closed-Loop Circulation
The operating liquid is separated from the pump discharge, cooled and returned to the vacuum pump for recirculation.
Compared with once-through water supply, this arrangement can significantly reduce fresh-water consumption and wastewater discharge.
Make-up liquid may still be required to compensate for evaporation, process carryover, drainage and other operating losses.
Working-Liquid Temperature Control
Liquid ring vacuum pump performance is strongly influenced by the temperature and vapour pressure of the operating liquid.
In a closed-loop system, heat generated during gas compression, incoming gas cooling and vapour condensation accumulates in the circulating liquid.
A properly sized heat exchanger removes this heat and maintains the operating liquid within the required temperature range, helping stabilize pumping performance and achievable vacuum.
Heat Exchanger Options
Heat exchanger type is selected according to the heat load, operating liquid, cooling-water temperature, fouling risk, corrosion requirements and maintenance requirements.
Plate Heat Exchanger
Compact, high thermal efficiency
Shell-and-Tube Heat Exchanger
Robust, suitable for higher fouling or pressure conditions
Other Process-Specific Cooling Equipment
Selected according to project requirements
Working Liquid
Water is the most common operating liquid. Alternative compatible operating liquids may be considered for specific process applications, subject to vapour pressure, material compatibility, temperature, safety and vacuum-performance requirements.
Condensate & Solvent Recovery
For processes containing condensable vapours, the system can be configured with upstream or downstream condensation and collection equipment to recover compatible process liquids.
Recovery-system design depends on vapour composition, concentration, temperature, pressure, cooling conditions and required recovery efficiency.
Liquid Ring Pump Options
The liquid ring vacuum pump is selected according to the required pumping speed, operating pressure, ultimate pressure, gas composition, vapour load, corrosion requirements, operating liquid and continuous-duty requirements.
2BVA / 2BVA(F)
Single-stage liquid ring, standard and corrosion-resistant
2S / 2S(F)
Two-stage liquid ring, standard and corrosion-resistant
2BE
Double-acting liquid ring, high-capacity applications
LD / LD(F)
Single-stage liquid ring, standard and corrosion-resistant
Typical System Components
Components are selected according to process requirements and are not necessarily included in every system.
Typical Components
- Liquid Ring Vacuum Pump
- Gas-Liquid Separator
- Heat Exchanger
- Circulation Tank / Separator Vessel
- Working-Liquid Circulation Piping
- Vacuum Valves
- Check Valve
- Temperature Instrumentation
- Pressure / Vacuum Instrumentation
- Level Instrumentation
- Control Panel
- Base Frame / Skid
Optional Equipment(per process requirements)
- Pre-Condenser
- Post-Condenser
- Condensate Collection Tank
- Filter
- Knock-Out Pot
- Demister
- Automatic Make-Up System
- Drain System
- Cavitation-Protection Line
- VFD
- PLC / HMI
Control & Automation
Automatic and PLC-based control configurations are available according to project requirements.
Multi-Pump Configurations
Multi-pump systems can be configured for duty/standby operation, capacity control or redundancy according to process requirements.
Corrosion-Resistant Configurations
Corrosion-resistant pump, piping, separator and heat-exchanger material configurations are available for compatible chemical process applications. Material selection must be confirmed according to process medium, concentration, temperature, operating liquid, chloride content, solvent compatibility and cleaning requirements.
Hazardous-Area Applications
Systems for hazardous-area applications can be configured with suitable explosion-protected motors, electrical components, instrumentation and grounding arrangements according to project and site requirements.
Cavitation Protection
Cavitation-protection arrangements can be incorporated where required to help reduce cavitation risk during low-inlet-pressure operation. Actual configuration depends on pump model, operating-liquid temperature and system pressure.
Typical Applications
Closed-loop liquid ring vacuum systems are used across a wide range of process industries.
Chemical Processing
Vacuum distillation, evaporation, crystallization and process vacuum
Pharmaceutical Processing
Vacuum drying, concentration and compatible process applications
Solvent Recovery
Vacuum systems with condensation and recovery of compatible process vapours
Petrochemical Processing
Process vacuum, gas recovery and compatible hydrocarbon applications
Vacuum Drying
Stable closed-loop vacuum generation for industrial drying processes
Environmental & Recovery Systems
Vacuum-assisted gas collection, condensation and process-liquid recovery
Custom Engineering
Each closed-loop liquid ring vacuum system is engineered according to the customer's process conditions.
Zhongtian can provide system configuration and engineering support including pump selection, separator sizing, heat-exchanger matching, piping layout, instrumentation and control integration.
Discuss Your RequirementsPerformance & Specifications
System performance is determined by the selected liquid ring vacuum pump, operating-liquid conditions, heat-exchanger capacity, gas load and process requirements. Closed-loop liquid ring vacuum systems are custom-engineered — please contact Zhongtian with your process requirements for a system-specific quotation.
Project Information Required
To prepare a system configuration and quotation, please provide the following process information where available.
Submit Project EnquiryProject Gallery
System photos, assembly images and project case studies will be added here.
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