Dynamic flow balancing valves are also known as pressure independent control valves (PICV) , self-operated balancing valves, constant flow valves, and automatic balancing valves.
What is a Pressure Independent Control Valve?
Pressure independent control valve (PICV) automatically changes the drag coefficient according to changes in system operating conditions. Within a certain pressure difference range, the flow rate can be effectively controlled to maintain a constant value, that is, when the pressure difference between the front and the back of the valve is increased, the flow can be kept not increased by the automatic closing action of the valve. Conversely, when the pressure difference is reduced, the valve automatically opens and the flow remains constant. However, when the pressure difference is less than or greater than the normal working range of the valve, it cannot provide an additional pressure head after all, and the flow rate of the valve to the fully open or fully closed position is still lower or higher than the set flow rate.
Pressure independent control valve, also known as dynamic flow balancing valve, flow control valve, dynamic balancing valve, constant flow dynamic balancing valve. The automatic flow balance valve controls the flow through the valve by automatically changing the overflow area of the spool and adapting to the pressure changes before and after the valve. Its flow rate can be set at the production plant, or it can be set on site or electronically adjusted as required.
The automatic flow balancing valve is actually a constant flow valve that keeps the flow constant. Its function is: when some terminal equipment such as fan coil unit, fresh air unit and other control valves in the system adjust with the change of air conditioning load, resulting in the change of pressure in the pipeline network, so that the flow of other terminal equipment remains unchanged, still consistent with the design value.
According to the different flow setting modes, automatic flow balancing valves can be divided into two categories: fixed flow type and field set flow type.
Advantages of Pressure independent control valves
Pressure independent control valve enables the valve bile to change according to the pressure difference of the water system from time to time, ensuring that it will not exceed the original set water flow and absorb excessive pressure difference, thus realizing the automatic balance of pressure and flow of the whole water system. Therefore, using it has the following benefits.
For owners and construction units:
- (1) There is no need for system debugging: it can save you a lot of time and shorten the completion date;
- (2) There is no need to install the same process management: it can increase the area and space used for you, save installation and material costs;
- (3) Easy to use: the water system balance will not be affected by the phased completion of the project installation or the phased use of the equipment;
- (4) Convenient change: When water systems in some areas need to be redesigned, the design and balance of water systems in other areas will not be affected.
- (5) Reduce power consumption: As the whole water system is balanced, the refrigeration units (boilers, heat exchangers) and pumps are guaranteed to operate in the best working state, which has obvious energy-saving effect;
- (6) Reduce wear and waste: to ensure that water flow will not exceed the original design, to ensure the durability of all equipment, to avoid excessive flow caused by copper pipe loss;
- (7) Improving safety: Because the flow balance of water system is automatic, the possibility of destructive regulation is eliminated.
- (8) For the designer, the workload is reduced: there is no need to calculate the resistance of the whole pipeline to accelerate the design speed;
- (9) It is possible to use the different program system boldly: save pipes, corresponding materials and installation costs, and transfer the work of the balancing hydraulic system to the dynamic flow balancing valve to complete. Many other troubles caused by unbalanced water systems can be avoided.
Working principle of Pressure Independent Control Valves
Highly controlled and efficient building environment requires system design engineers to endow novel design concepts in their design. Because of the increasing use of various kinds of fluid control systems, especially the combination of temperature control devices and regional control functions, the use of static balance valves is out of date.
The pressure independent control valve(PICV) combines innovative design and provides a complete solution to the hydraulic balancing system with maximum flexibility. The original design of the automatic balancing valve is a balancing valve specially designed for refrigeration and heating systems. The use of automatic control valve gallbladder ensures that the flow rate is the designed flow rate and remains constant even in the case of pressure fluctuation.
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