Pressure Transmitter in Constant Pressure Water Supply

Industrial Background

With the rapid development of cities, the population is constantly increasing. Various buildings such as high-rise residential, commercial buildings, hospitals, schools are largely appearing. They have high demands for water supply and concentrated water use time. At the same time, they also have the high requirements for stability of the water supply pressure. Fox example the high-rise residential, owing to the high floors, it is needed the sufficient water pressure to ensure the normal use of the users. These make a higher request for pressure control of the water supply system.

Different places have different water demand characteristics, for example, water consumption in residential areas is mainly concentrated during the morning and evening peak periods, however, water use in places like the factories and commercial centers are relatively constant and in large fluctuations. The constant pressure water supply system needs to adjust pressure and flow according to the water use characteristics of different places to meet customers’ needs.

Introduction to the Constant Water Supply System

The constant water supply systems are mainly composed of water pumps, frequency converters, pressure transmitters, and controllers. The controller automatically adjusts the frequency converters and water pumps so that the water pump can automatically adjust according to the system. 

Details are as follows,

1. The controller monitors pressure of the water supply pipes in real time through pressure transmitter;

2. The controller controls the frequency converter and adjusts the running frequency of the water pump according to the preset target pressure.

3. The frequency converter controls the speed of the motor by changing the frequency of the power supply, and controls the output of the water pump.

4. The controller adjusts the running status of the water pumps in real time according to the differences between actual pressure and target pressure to keep the pressure of the water supply system constant.

The system diagram is as follows

Core of the System

In the entire constant water supply system, the most important is the pressure control. The system is controlled through the deviation between the target pressure and the actual pressure. Therefore, the pressure transmitter accuracy and stability decides the reliability of the entire system.

Pain points of the system

1.The pressure monitoring point in the water pump outlet has water hammer effect when the pump starts and ends. It causes great influence and even damages the pressure transmitter, and causes system error.
2.The accuracy and stability of the pressure transmitters cannot meet the needs, they work well in the early stages of the system, however, the pressure transmitters will cause large offsets over time and temperature, and cause influence on systems with ambient temperature changes and long time periods.

Recommended products

For the constant pressure water supply industry, we deeply researched, and learned about its pressure range. Generally, residences are at 2-4 bar, commercial architectures are at 3-6 bar, the industrial applications are generally at 4-10 bar. The accuracy of the pressure transmitters are required to control at 1% to 0.1%.

We designed and recommended GPT203 pressure transmitter. The transmitter adopts diffused silicon fully-welded structure, and the input outlet method and is designed to reach IP68 protection level. The products are carried out the processes such as component screening, process verification and curing, cyclic loading and stress relief, aging, and environmental simulation testing, and the accuracy can reach to 0.1%F.S. The products are designed with the removable damping screw. The customers can decide according to the onsite working conditions, and prevent the water hammer from damaging the sensors caused by false installation places, and provide real and reliable pressure data for constant pressure water supply.

Customer Actual Applications

1.Residential area：Install pressure transmitters on outlets of the water pumps and on each floor to realize constant pressure water supply of the entire residential area. The system can automatically adjust the water pump speed according to the actual needs and ensure the average water pressure of each floor.
2.Large shopping mall: Install pressure transmitter on water supply pipes of each floor to adjust the water pump operating parameters in real time through the central control system to ensure the average water pressure of each floor.