Product Introduction

A non-negative pressure water supply system connects to the municipal water supply network and directly boosts the pressure to supply buildings or groups of buildings where the incoming water pressure is insufficient. It eliminates the secondary contamination caused by water tanks and reservoirs in traditional secondary pressurization systems, ensuring hygienic and safe water quality. It also makes effective use of the existing pressure in the water network, delivering significant energy-saving and environmental benefits.

The GDW non-negative pressure water supply system is a new-generation product developed using an innovative approach. After extensive testing, we pioneered the concept of a “non-negative pressure water supply system.” Rather than treating it as an independent piece of equipment, we designed it as an integrated system comprising the equipment, the municipal water supply network, and end users.

Accordingly, we developed a design concept and technical approach that use a more effective intelligent control system to ensure that the equipment “does not generate negative pressure at all” and is “truly fully sealed.” The system comprehensively meets water network requirements and safeguards network security and stable operation. It prevents excessive water withdrawal and avoids pressure surges in the network. By closely integrating the urban water supply system (primary water supply) with the building water supply system (secondary water supply) into a “direct water supply system,” this pressure-boosting equipment ensures safe, continuous, and coordinated system operation. This technology has been included among the projects promoted nationwide by the Ministry of Construction of China.

We have now applied wireless transmission technology to water supply equipment control and data transmission, enabling equipment fault warnings and remote commissioning and significantly reducing repair time.

Equipment Components

The complete system consists of a flow-stabilizing tank, vacuum suppressor, variable-frequency speed-controlled pump unit, pressure sensor, variable-frequency control cabinet, backflow preventer (optional), disinfection unit (optional), and small-flow pressure-maintenance tank (optional). The inlet pipe from the municipal water network connects directly to the inlet of the flow-stabilizing tank. The tank outlet connects to the inlet pipe of the booster pump unit through the disinfection unit, and the pump unit outlet pipe connects to the user's water supply pipe, supplying water directly to the user's network.

Working Principle

Connecting a pump in series with a water supply network has long been considered unacceptable. National urban water supply regulations stipulate that “directly installing pumps on urban water supply pipelines to draw water is prohibited.” The main reasons are that direct pumping can create negative pressure, or a vacuum, in the pipeline, resulting in excessive water withdrawal by individual users and a sharp drop in network pressure that affects normal water use by neighboring users. It can also cause backflow, air accumulation, and pressure fluctuations in the pipes, adversely affecting water supply network operation.

The GDW series direct-in-line automatic pressure-boosting water supply system launched by our company (also known as the GDW series non-negative pressure water supply system) is based on in-depth research into the mechanisms that generate negative pressure. Its design concept eliminates the conditions that cause negative pressure so that it cannot occur. Using intelligent control technology, the system automatically controls pump operating conditions and water flow, smoothly and stably adjusting pump discharge flow to meet user demand while preventing negative pressure and complying with water network constraints. The core technology is the automatic control system for variable-frequency speed-controlled pumps. It comprises a hardware system consisting of high-performance frequency converters, programmable logic controllers, microcontrollers, pressure and level sensors, and industrial control components, as well as intelligent control algorithms and software.

Equipment Features

Lower investment: Reduces investment by approximately 50%. No storage reservoir or rooftop water tank is required. Pressure-superimposed water supply reduces initial equipment costs.

High efficiency and energy savings, with low operating costs: Makes full use of the municipal water network's supply pressure, supplementing only the pressure difference required without generating negative pressure. Compared with traditional water supply equipment, it can save 30%–90% in energy. Municipal water pressure can continue to supply water during a power outage.

Highly intelligent, easy to operate, and labor-saving: The equipment is controlled by a fully automatic intelligent controller that adjusts operation according to user water consumption and the municipal network's water pressure, enabling unattended operation. A human-machine interface displays text and numerical information, giving customers a clear view of operating conditions.

Environmentally friendly and hygienic: The equipment operates in a fully enclosed system, completely eliminating secondary water contamination.

Comprehensive protection functions: Includes automatic protection against overload, short circuits, overvoltage, undervoltage, phase loss, overcurrent, and water source shortage. In the event of an abnormal condition, the system can issue alarms and perform self-diagnostics and fault identification.

Compact footprint and easy installation: The complete system consists of just three parts: a water supply control cabinet, a non-negative pressure flow-stabilizing tank, and a pump unit, making installation simple and convenient.

Extended equipment service life: Reliably provides soft starting for multiple pump units, preventing impact on the power and water supply networks. The pumps operate in rotation, significantly extending the service life of the pumps and motors. Equipment service life can be extended by more than three times.

Water supply continues during power outages: If the power supply is interrupted, a bypass allows water supply to continue. The system automatically switches to supply water at municipal mains pressure.

Highly automated: The system provides fully automatic control, including manual/automatic switching, scheduled rotation of primary and secondary pumps, pressure adjustment, constant-pressure control, high- and low-voltage protection, phase-loss protection, leakage protection, overload protection, overheat protection, low-water protection, shutdown when there is no water demand, and instantaneous trip protection. A human-machine interface can also be configured according to user requirements for visual remote adjustment, monitoring, and maintenance.

The complete system is designed and manufactured to meet high standards for quality, low noise, long service life, maintenance-free operation, and ease of use. It is backed by comprehensive after-sales service, giving users confidence in their purchase and peace of mind in operation.

Applications

Domestic water supply for high-rise buildings, residential communities, and villas;

Daily water supply for enterprises and institutions, office buildings, schools, sports stadiums, golf courses, airports, and other facilities;

Production water supply for manufacturing, the food industry, factories, and mines;

Sprinkler irrigation stations for large plazas, parks, green spaces, and farms;

Comprehensive retrofitting of existing water supply systems with reservoirs or tanks to eliminate water contamination;

Intermediate booster stations for long-distance water supply in urban and rural water supply systems, booster stations for regional water supply networks, and booster stations for centralized water supply in elevated areas.

Technical Parameters

Flow range: ≤10000m3/h

Pressure range: 4-400m

Power per pump: ≤315kw

Pressure adjustment accuracy: ≤0 . 001Mpa

Ambient temperature: 0-40℃

Relative humidity: Below 90%; outdoor type, below 95% non-condensing

Power supply: 380v, 50HZ