How Much Do You Know About The Balancing Valve?
What is a balancing valve?
The concept of the balancing valve.
A balancing valve is a valve with special functions. In some industries, due to a large pressure difference or flow difference of the medium (various flowable media, such as gases, liquids, etc.) in different parts of the pipeline or container, in order to reduce or balance this difference, a valve is installed between the corresponding pipelines or containers to regulate the relative balance of the pressure on both sides, or to achieve the balance of the flow rate through the method of shunting.
A balancing valve plays the role of dynamic and static balance adjustment under hydraulic working conditions.
The structure of the balancing valve.
The balancing valve is composed of the valve body, the valve core, the adjusting screw, the handwheel, the dial and the sealing pad.
- Valve body: The valve body is the main part of the balancing valve, usually made of cast iron, cast steel, stainless steel or copper to meet the requirements for strength, corrosion resistance and high-temperature resistance under different working conditions. It has two ports, namely the inlet and the outlet, and is also equipped with a water port and a vent port.
- Valve core: The valve core is a key component of the balancing valve, generally made of wear-resistant and corrosion-resistant materials, such as copper, ceramics, stainless steel or polymer materials, etc. It is the core component of the balancing valve, and it regulates the flow rate and pressure of the fluid by changing the gap between it and the valve seat.
- Valve seat: It is used in conjunction with the valve core to provide sealing to prevent the fluid from leaking when the balancing valve is closed, and it also supports the valve core.
- Material: It is usually made of the same material as the valve body to ensure its compatibility and strength matching with the valve body.
- Adjusting mechanism: It is used to change the position of the valve core, thereby achieving precise control of the fluid flow rate and pressure. Some regulating mechanisms can also realize remote control or automatic adjustment functions.
- Sealing pad: The sealing pad is a rubber sealing element to prevent the fluid from leaking between various connection parts and moving parts of the valve, and to ensure the sealing performance and normal operation of the valve.
Types of balancing valves.
I. Static balancing valve(SBV)
This type of balancing valve can regulate the flow rate and is usually used in static fluid systems, such as central air conditioning, heating, and water supply. Its main function is to maintain the stability of the water flow rate in the system and avoid various problems caused by abnormal water flow rates, such as noise and water leakage. The static balancing valve is usually adjusted manually or automatically.
- Manual balancing valve
The manual balancing valve is a device that adjusts the opening of the valve manually to control the fluid flow rate. Its structural design is simple, and it is quite convenient to operate. However, since the adjustment process is done manually, there may be some deficiencies in accuracy. - Differential pressure self-balancing valve
The differential pressure self-balancing valve is a device that can automatically adjust the valve opening. It uses the pressure difference of the fluid itself to maintain the balance of the flow rate.
The static differential pressure self-balancing valve mainly balances the pressure difference based on its pre-set fixed resistance coefficient. During installation, the valve needs to be set once according to the design working conditions of the system (such as flow rate, differential pressure, etc.). Once set, under normal operating conditions, its adjustment function is relatively fixed and will not be adjusted frequently with small fluctuations in the system pressure. This type of valve is more suitable for occasions where the system working conditions are relatively stable, such as small-scale, single-function industrial circulating water systems or simple water supply and drainage systems.
II. Dynamic balancing valve(DBV)
A dynamic balancing valve is a type of valve that can automatically regulate the flow rate. It is mainly used in dynamic fluid systems, such as water circuit balancing and variable air volume air – conditioning systems. Its characteristic is that through the movement of the internal valve core, it automatically adjusts the opening degree of the valve according to the actual flow rate to maintain the balance of the water flow rate in the system. Dynamic balancing valves usually have an automatic control function, enabling remote monitoring and control.
The dynamic balancing valve can also be divided into two types:
- Dynamic flow balancing valve
The dynamic flow balancing valve is a device that can automatically maintain a constant flow rate during the operation of the system. It adopts a self-operated structure, which can sense the changes in the fluid flow rate and automatically adjust the valve opening accordingly to ensure the stability of the flow rate. This balancing valve also has the characteristics of energy conservation, environmental protection, compact structure, and simple operation. - Dynamic differential pressure self-balancing valve
The dynamicdifferential pressure self-balancing valve can automatically and dynamically adjust the valve opening according to the real-time pressure changes in the system. It usually has an element (such as a diaphragm, piston, etc.) that can sense the differential pressure changes inside. When the differential pressure at the inlet and outlet of the system changes, this sensing element will drive the valve core to move. The dynamic self-operated differential pressure balancing valve has the characteristic of rapid response. It can start to adjust the valve opening at the moment of system pressure fluctuations and continuously adjust the valve opening according to the actual working conditions during the operation of the system to ensure the stability of the differential pressure. This type of valve is suitable for complex working conditions where the system pressure and flow rate change frequently, such as large-scale central heating systems or air conditioning systems in hospitals.
III. Pressure independent balancing valve.
It works within a specific flow rate or differential pressure range and maintains the stability of the system through a mechanical feedback mechanism, which is suitable for high-precision control scenarios.
How does a balancing valve work?
The operation of the balancing valve is based on the principles of fluid mechanics. When the fluid passes through the balancing valve, changes in the flow area between the valve core and the valve seat will lead to corresponding adjustments in the flow rate and pressure. Its internal structure includes components such as a spring, a valve core, and a valve seat. The spring provides a pre-tightening force to ensure that the valve core can be maintained in an appropriate position under various working conditions, thereby regulating the flow rate and pressure.
When the system flow rate or pressure changes, the balancing valve will self-regulate the position of the valve core to maintain stability. For example, when the flow rate increases, the balancing valve will reduce the flow area and increase the fluid resistance, thereby reducing the flow rate. Conversely, when the flow rate decreases, it will increase the flow area and reduce the fluid resistance to increase the flow rate. Similarly, when the pressure changes, the balancing valve will also adjust the valve core to maintain pressure stability.
