Case
Case
This article will elaborate on the definition, function, working principle, advantages, applicable working conditions and installation and maintenance methods of flow regulating valves from many aspects, giving you a comprehensive understanding of flow regulating valves.
Flow Regulating Valve is a valve used to regulate and control fluid flow. It adjusts the fluid flow through the valve by changing the size or shape of the flow channel, thereby achieving precise control of the flow.
Depending on the application requirements, the flow regulating valve can be manual or automatically controlled. Automated flow regulating valves are usually equipped with an actuator, which can receive signals from the control system and automatically adjust the opening of the valve to achieve remote control and precise adjustment of flow.
The flow regulating valve has multiple functions in the fluid control system, including:
Adjust flow: The main function of the flow regulating valve is to control the fluid flow by adjusting the opening of the valve to meet process requirements. It can control the fluid flow within the set range and keep the system running stably.
Stable system pressure: In many fluid systems, stable flow often means stable pressure. By controlling the flow regulating valve, the pressure fluctuation of the system can be effectively stabilized to ensure safe and reliable operation of the system.
Energy saving and consumption reduction: Through precise flow control, the flow regulating valve can avoid unnecessary fluid waste, thereby achieving the effect of energy saving and consumption reduction.
Prevent overload: In some situations where equipment needs to be protected, by controlling the flow regulating valve, the equipment can be prevented from being overloaded due to excessive flow or pressure, thereby protecting the safety of the equipment.
The working principle of the flow regulating valve is based on changing the cross-sectional area or shape of the fluid channel to control the fluid flow. Its internal structure usually includes key components such as valve body, valve core, valve seat and actuator. The movement of the valve core (rotation or linear motion) directly affects the opening of the valve, thereby changing the cross-sectional area of the flow channel through which the fluid passes, thereby adjusting the flow rate.
Manual adjustment: The manually adjusted flow regulating valve directly controls the movement of the valve core through a handwheel or handle to adjust the fluid flow. The operator can manually adjust the valve by observing the flow meter or other indicating device, which is suitable for systems with small flow changes.
Automatic adjustment: The automatic adjustment flow regulating valve is equipped with an actuator and a controller. By receiving feedback signals from the flow sensor or flow meter, the actuator automatically adjusts the position of the valve core to achieve automatic flow control. Common actuators include electric, pneumatic and hydraulic actuators.
Control method: The flow regulating valve can be proportionally adjusted according to the flow feedback signal, or it can be controlled at a constant flow according to the set value. Through advanced PID control algorithm, precise control of flow can be achieved to meet process requirements.
There are various driving methods for flow regulating valves. Depending on the application requirements and site conditions, common driving methods include manual, electric, pneumatic and hydraulic. Each driving method has its unique advantages and applicable scenarios.
Features:
- Manually adjust the valve core position through the handwheel or handle to control the flow.
- Simple structure, low cost, no need for additional power or gas source support.
- Suitable for occasions where the flow rate changes slightly and frequent adjustments are not required.
Applicable scenarios:
- Small equipment or systems with little flow change and low operating frequency.
- Places without power or gas supply, or environments where on-site maintenance is convenient.
Features:
- Driven by an electric actuator, the valve core position is adjusted by the motor to achieve automatic flow control.
- Can be connected to the control system to receive control signals (such as 4-20mA or 0-10V) to achieve remote or automatic control.
- Rapid response and high control accuracy, suitable for occasions requiring fine flow adjustment.
Applicable scenarios:
- Working conditions that require remote or automated control, such as industrial process control systems and building automation systems.
- An environment with sufficient power supply.
Features:
- Driven by a pneumatic actuator, using compressed air as the power source, the position of the valve core is adjusted by controlling the pressure of the air source.
- Fast response speed, suitable for frequent switching situations.
- Pneumatic actuators are intrinsically safe (no risk of sparks) and suitable for use in flammable and explosive environments.
Applicable scenarios:
- Petrochemical, natural gas processing and other occasions where explosion protection is required.
- Control systems that require fast response, such as rapid switching or emergency shutdown applications.
Features:
- The hydraulic actuator is powered by the hydraulic system and can generate a large driving force for adjusting the valve core position.
- Suitable for valve adjustment with large diameter and high pressure difference.
- The control accuracy is high, but the system complexity is relatively high and the hydraulic system needs to be maintained.
Applicable scenarios:
- High-pressure systems or valves requiring large torque actuation, such as large-diameter pipeline systems.
- Special industrial applications, such as fluid control in hydropower stations and heavy machinery equipment.
Features:
- Combining the advantages of electric and hydraulic drives, the electric motor drives the hydraulic pump and controls the hydraulic actuator.
- It has high control precision and large driving force, and also has the automation characteristics of electric drive.
- Suitable for applications with higher requirements, such as fluid control of large industrial equipment and complex systems.
Applicable scenarios:
- Applications requiring high precision and high torque control.
- Industrial places with high automation requirements.
Site conditions: Choose the appropriate driving method based on whether there is a power or gas source, whether explosion protection is required, etc.
Control requirements: Select the appropriate actuator according to the system's requirements for flow control accuracy and response speed.
Economy: Manual drive is usually the lowest cost, but automated drive can reduce manpower and improve the overall efficiency of the system.
Maintenance requirements: Different drive modes have different maintenance difficulties and frequencies, which need to be selected according to on-site maintenance conditions.
The reasonable selection and matching of different driving methods can effectively improve the application effect of the flow regulating valve in various working conditions and ensure the efficient operation of the fluid control system.
As a widely used fluid control device, flow regulating valve has the following advantages:
High-precision control: The flow regulating valve can achieve high-precision control of fluid flow and is suitable for occasions requiring precise flow regulation.
Fast response speed: The actuator of the automatic flow regulating valve has a fast response speed and can quickly adjust the valve opening to cope with rapid changes in flow.
Compact structure: The flow regulating valve has a compact design and takes up little space, making it suitable for installation in places with limited space.
Easy maintenance: The structural design of the flow regulating valve facilitates disassembly and maintenance, reducing maintenance workload and downtime.
Strong durability: The high-quality flow regulating valve is made of corrosion-resistant and wear-resistant materials and can operate stably for a long time under harsh working conditions.
Significant energy saving effect: Through precise flow control, the flow regulating valve can significantly reduce fluid waste, thereby achieving energy saving effects.
Flow regulating valves are widely used in various working conditions that require precise flow control, including but not limited to the following occasions:
Chemical industry: In the chemical production process, flow regulating valves are used to control the flow of raw materials, catalysts and reaction products to ensure the stability and safety of the reaction.
Oil and natural gas industry: used in oil and gas extraction, transportation and refining processes to control the flow of oil and gas mixtures to ensure the safety and efficiency of the production process.
Water treatment industry: In water treatment plants and sewage treatment plants, flow regulating valves are used to regulate water flow to ensure stable water quality and treatment effects.
Electric power industry: In thermal power, nuclear power and other power plants, flow regulating valves are used to regulate the flow of cooling water, steam and fuel to ensure the stable operation of the power generation process.
HVAC system: In heating, ventilation and air conditioning systems, flow regulating valves are used to regulate the flow of heating and cooling systems to ensure indoor temperature comfort and energy-saving operation of the system.
Industrial manufacturing: Flow regulating valves are widely used in various fluid delivery systems in the manufacturing industry, such as coolant, lubricating oil and gas delivery systems.
Installation location:
The flow regulating valve should be installed in a location that is easy to operate and maintain, and ensure sufficient surrounding space for easy disassembly and maintenance.
Pipe cleaning:
Before installation, ensure that there are no impurities and welding slag in the pipeline to prevent debris from entering the valve body and damaging the valve core and seals.
Flow direction matching:
Ensure that the installation direction of the valve is consistent with the flow direction of the medium. Usually there is an arrow marking the flow direction on the valve body.
Sealing:
Make sure all connections are well sealed to prevent leaks. For flange-connected valves, the bolts should be tightened evenly to avoid uneven stress.
Regular inspection: Regularly check the working status of the seals, valve core and actuator of the flow regulating valve. If any wear or aging is found, replace it in time.
Cleaning and maintenance: Keep the valve body and surrounding environment clean to prevent debris from entering the valve. For valves that have not been used for a long time, they should be operated regularly to prevent the valve core from getting stuck.
Lubrication and maintenance: For the mechanical transmission part, regular lubrication and maintenance should be carried out to ensure the flexibility of valve opening and closing.
Actuator maintenance: For automatically adjusted flow regulating valves, the electrical and pneumatic systems of the actuator should be checked regularly to ensure the accuracy of the control signal and execution response.
Abnormal flow: If abnormal flow is found, check whether the valve core is stuck or worn, and check whether the feedback signal of the actuator is normal.
Leakage problem: If a valve is found to be leaking, you should check the integrity of the seal and confirm whether it is installed correctly.
Noise or vibration: If abnormal noise or vibration occurs, you should check whether the installation of the valve is stable and whether the movement of the valve core is smooth.
As a key device in fluid control systems, flow regulating valves play an important role in various industries. Understanding the working principle, application scenarios, and key points of installation and maintenance of flow regulating valves will help improve the service life and work efficiency of the equipment. Through scientific selection, correct installation and regular maintenance, the flow regulating valve can be ensured to maintain stable and efficient operation under complex working conditions, providing reliable guarantee for system safety and energy saving.
