What are the performance characteristics of flow control valves, and what are the commonly used flow

The flow rate can be set according to the design or actual requirements, which can automatically eliminate the differential pressure fluctuation of the system and keep the flow rate unchanged. Overcome the uneven heating and cooling of the system and improve the quality of heating (cooling).

Completely solve the contradiction of large proximal pressure difference and small distal pressure difference.

Reduce the amount of water circulating in the system and reduce the resistance of the system.

Reduces design effort and eliminates the need for tedious hydraulic balance calculations for the pipe network.

Reduce the difficulty of network adjustment, and simplify the complex network adjustment work into simple traffic distribution.

Eliminate the need for flow redistribution when switching heat sources in a multi-source network.

The displayed values of the flow rate are randomly calibrated on the test bench, and the flow rate (m3 h).

ZLF (ZL-4M) flow control valve, also known as self-operated balancing valve, flow control valve, flow controller, dynamic balancing valve, flow balancing valve, is an intuitive and simple flow regulation control device, the application of flow control valve in the pipeline network can directly set the flow rate according to the design, the valve can be under the action of water, automatically eliminate the flow deviation caused by the remaining pressure head and pressure fluctuations of the pipeline, no matter how the system pressure changes, keep the set flow unchanged, these functions of the valve make the flow regulation of the pipeline network complete at one time, The network adjustment work is turned into a simple flow distribution, and the hydraulic imbalance of the pipe network is effectively solved. The flow control valve is mainly used in water systems such as central heating (cold), so that the flow of the pipe network is distributed on demand, the hydraulic imbalance of the water system is eliminated, and the problem of uneven cold and heat is solved, which can save energy and save 15%-20% of electricity.

Technical parameters of flow control valves:

Medium temperature: 0-150;

Operating temperature: 150 °C;

Working pressure:;

Working pressure difference: 20-600kpa;

Flow accuracy: 5.

Material and life of the flow control valve:

Body – High quality grey cast iron.

Internals - brass, stainless steel.

Springs — stainless steel.

Diaphragm — EPDM.

Lifespan — more than 10 years.

Selection of flow control valves:

It can be selected according to the equal diameter of the pipe. Baicheng Fulaike filter valve, Baicheng Fulaike controller.

It can be selected according to the maximum flow rate and the flow range of the valve.

The structure of the digital flow control valve is composed of automatic valve core, manual valve core and display part. The display part is composed of the flow valve movement, the sensor transmitter, and the electronic calculator display part. Its work is extremely complex.

The measured water flows through the valve, the water flow hits the impeller in the flow movement, the impeller rotates and the sensor transmitter induces, so that the sensor sends out a telecommunication signal proportional to the flow rate, and the flow telecommunication signal is sent to the electronic calculator through the wire, and the flow value is displayed after the calculator calculation and microprocessor processing. The manual spool is used to adjust the flow rate, and the desired flow value is set according to the displayed value. The automatic valve core is used to maintain a constant flow rate, that is, when the pressure of the pipe network changes, the automatic valve core will automatically open a large fire and close the small valve port under the action of pressure to maintain the set flow value.

There are many variety.

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following are the top ten domestic first-line valve brand manufacturers in 2022-2023, but for reference only: Suzhou Neway Valve Co., Ltd., Shanghai Guanlong Valve Machinery, Shanghai Qizhong Valve Manufacturing, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

Flow control valves.

The flow rate is regulated by adjusting the area of the orifice between the spool and the valve body and the local resistance it generates, thereby controlling the speed of movement of the actuator. There are 5 types of flow control valves according to their application. (1) Throttle valve:

After adjusting the area of the orifice, the movement speed of the actuator with little change in load pressure and low motion uniformity requirements is basically stable. (2) Speed control valve: when the load pressure changes, the inlet and outlet pressure difference of the throttle valve can be kept as a fixed value.

In this way, after the throttle area is adjusted, the speed control valve can keep the flow through the throttle unchanged regardless of the change of load pressure, so that the movement speed of the actuator is stable. (3) Diverter valve: regardless of the size of the load, the equal flow valve or synchronous valve that can make the two actuators of the same oil source obtain the same flow rate; The proportional flow rate is obtained by the proportional diverter valve.

4) Collector valve: The effect is opposite to the diverter valve, so that the flow rate flowing into the collector valve is proportionally distributed. (5) Diverter collector valve:

It has both the functions of a diverter valve and a collector valve.

Driving routes: The whole journey is about kilometres.

Starting Point: Pudong New Area.

1.From the starting point, head northwest along Jindai Road for 210 meters and turn left onto Lilac Road.

2.Drive along Lilac Road for 350 meters and turn right onto Century Avenue.

3.Drive along Century Avenue for 260 meters, turn right into Yanggao Road interchange.

4.Drive 100 meters along the Yanggao Road interchange, towards Yan'an East Road Tunnel, Xinjian Road Tunnel, Renmin Road Tunnel and Dalian Road Tunnel, and turn slightly right into Century Avenue.

5.Drive along Century Avenue for kilometers and turn right into Lujiazui Ring Road.

6.Drive along Lujiazui Ring Road for 140 meters, pass the China Insurance Building on the right for about 60 meters, and enter Lujiazui East Road.

7.Drive 240 meters along Lujiazui East Road and go straight into Century Avenue.

8.Drive along Century Avenue for 250 meters, cross the Yincheng Road interchange for about 170 meters, and go straight into the Yan'an East Road Tunnel.

9.Drive along the East Yan'an Road Tunnel for kilometers, pass the Yanhe Building on the right for about 80 meters, and then go straight into East Yan'an Road.

10.Drive along East Yan'an Road for 140 meters, pass the Huangpu District Office Building on the right for about 150 meters, and turn slightly right onto the ramp.

11.Drive along the ramp for 350 meters and go straight onto Yan'an Elevated Road.

12.Drive along the Yan'an Elevated Road for kilometers, cross the Wanbao International Plaza on the right, Tiananmen Square is at the Jiangsu Road exit, and turn slightly right onto the ramp.

13.Drive along the ramp for 240 meters and go straight onto West Yan'an Road.

14.Drive along Yan'an West Road for 10 meters, pass the Huamin Hanzun International West Building on the right for about 150 meters, and turn right into Jiangsu Road.

15.Drive along Jiangsu Road for a kilometer, pass the Zhongxi Building on the right for about 200 meters, and turn left into Changning Road.

16.Drive along Changning Road for 570 meters and turn left.

17.Drive 10 meters to the end (on the left side of the road).

Destination: Changning District.

The function of the flow control valve is to change the liquid resistance by changing the size of the flow area of the valve port or the length of the channel, and the flow control valve is to control the flow rate of the flow valve, so as to realize the adjustment and control of the movement speed (or speed) of the hydraulic actuator. Commonly used flow control valves include throttle valves, speed control valves and overflow throttle valves, among which throttle valves are the simplest but most widely used flow control valves.

Characteristics and application of throttle valve: The advantages of throttle valve are simple structure, low cost and easy adjustment, but because there is no pressure compensation measure, the flow stability is relatively poor. It is often used in the hydraulic system of oil supply throttle speed regulation of fixed pump oil supply with little load change or low requirements for speed control accuracy, and sometimes it is also used in the volumetric throttle speed regulation hydraulic system of variable pump oil supply, and sometimes it can also be used to play the role of load resistance or actuator buffering.

Characteristics and application of speed control valve: The advantage of speed control valve is that the flow stability is good, but because the liquid flow passes through the speed control valve, it passes through one more liquid resistance, and the pressure loss is large. It is often used in the hydraulic system of oil supply throttle speed regulation of fixed pump oil supply with large load change and high speed control accuracy, and sometimes it is also used in the volumetric throttle valve speed regulating hydraulic system of variable pump oil supply.

Characteristics and application of relief valve: the inlet pressure of the relief throttle valve is the outlet pressure of the hydraulic pump, because it can change with the load, so the power loss is small, the system heating is small, and it has energy-saving significance. However, usually the spring of the pressure compensation device in the overflow throttle valve is harder, so the pressure fluctuation is larger, the flow stability is worse than that of the ordinary speed regulating valve, and it is more obvious when the flow rate is small, so the overflow throttle valve is only suitable for the throttle speed regulation system with large power and the speed stability requirement is not too high.

In addition, because the overflow throttle valve makes the outlet pressure of the pump change with the change of load pressure, and the difference between the two is only the difference between the pressure difference between the throttle valve orifice valve, therefore, the overflow throttle valve can only be arranged at the outlet of the hydraulic pump in use.

Control valves. The flow characteristics are the relationship between the relative flow rate of the medium flowing through the regulating valve and its opening under the condition that the pressure difference between the two ends of the valve remains constant. The flow characteristics of the control valve are linear, equal percentage, and parabolic.

There are three characteristics. The significance of the three note characteristics is as follows:

Equal percentage characteristic (logarithmic.

The relative stroke and the relative flow of the equal percentage characteristic are not in a straight line, and the change in flow caused by the change in the unit stroke at each point of the stroke is proportional to the flow rate at that point, and the percentage change in flow is equal. Therefore, its advantage is that the flow rate is small, and when the flow rate is large, the flow rate changes greatly, that is, it has the same adjustment accuracy in different openings.

Linearity (linearity).

The relative travel and flow of the linear properties are in a linear relationship. The change in flow rate caused by the change in the unit stroke is constant. When the flow rate is large, the relative value of the flow rate changes slightly, and when the flow rate is small, the relative value of the flow rate changes greatly.

Parabolic characteristics.

The flow rate varies proportionally to the two sides of the stroke, and generally has the intermediate characteristics of linearity and equal percentage characteristics.

From the analysis of the above three characteristics, it can be seen that in terms of its regulation performance, the equal percentage characteristics are the best, and its regulation is stable and the regulation performance is good. The parabolic characteristics are better than the adjustment performance of the linear characteristics, and any of the flow characteristics can be selected according to the requirements of different use occasions.

The flow characteristics of the control valve include the ideal flow characteristics and the working flow characteristics. The ideal flow characteristics refer to the flow characteristics under the condition that the pressure difference between the inlet and outlet of the control valve is fixed, and there are four characteristics: straight line, equal percentage, parabolic and quick opening.

In a real system, the pressure drop on both sides of the valve is not constant, and there are two main reasons for its variation. On the one hand, due to the characteristics of the pump, the system pressure generated by the pump increases when the system flow decreases. On the other hand, when the flow rate decreases, the resistance on the coil also decreases, resulting in a higher pump pressure being applied to the valve.

Therefore, the differential pressure between the inlet and outlet of the control valve is usually varied, in this case, the relationship between the relative flow rate of the control valve and the relative opening. This is called the working flow characteristic [1]. Specifically, it can be divided into the working flow characteristics of the series pipeline and the working flow characteristics of the parallel pipeline.

The flow characteristics of the control valve refer to the relationship between the relative flow rate of the medium to be regulated through the control valve and the relative opening of the control valve.

Intrinsic Characteristics (Flow Characteristics): The relationship between the flow coefficient and the stroke of the interception element (disc) as the shut-off element (disc) moves from the closed position to the rated stroke when the pressure drop through the valve is constant.

Typically, these properties can be plotted on a graph with the horizontal axis represented as percent travel and the vertical axis represented as percent flow (or CV value).

Since valve flow is a function of valve stroke and pressure drop through the valve, flow characterization testing at a constant pressure drop provides a systematic way to compare valve characteristic types. Typical valve characteristics measured in this method are linear, equal percentage, and quick opening.

Introduction: Flow control valve is a multi-functional valve, which uses high-precision way to control the flow rate. So how does a flow control valve work? What are its characteristics? Let's take a look.

Flow Control Valve Principle

The main structure of the digital flow control valve is the automatic valve core and the manual valve core. The display part includes the flow valve movement, electronic calculator display, sensor transmitter and other parts. It works when it is somewhat complicated.

When the measured water flow flows through the valve, it will impact the two wheels in the movement, but the impeller will rotate, and after rotation, it will induce the sensor, so that the sensor will send a certain electrical signal, which is proportional to the flow rate, and then the electronic signal will enter the electronic calculator through the wire, and then the electronic calculator will process and calculate it and display it.

The manual spool is used to adjust the flow rate, which is based on the data shown above. The automatic valve core automatically maintains a constant flow rate in time, and even when the pressure of the external pipe network changes, the automatic valve core will automatically adjust the value unchanged.

Features of flow control valves

1. The flow control valve discards the previous principle of pure mechanical reduction and is beneficial to the area, and uses the hair to minimize the loss of energy in the process of throttling.

2. It is relatively easy to control, the sensitivity is very high, and it is very safe and reliable, the debugging is relatively simple, and the use time is relatively long.

The flow control valve can automatically achieve a large balance of flow without connecting to the power supply, and it achieves a constant flow rate of the shed by keeping the water pressure in front and behind the plate hole consistent. Constant flow valves lock the flow through the valve without balancing the resistance. In this way, he can solve the problem of the dynamic dissonance of the system.

In practice, in order to maintain the efficient operation of individual chillers, cooling towers, etc., and these equipment, it is necessary to control the power of these equipment. From the end of the system, in order to avoid the interaction between dynamic regulation and bureau, it is necessary to add a branch at the end to limit the flow.

One of the shortcomings of the flow control valve is that the valve has the minimum working volume requirements, generally speaking, the product requires a minimum working pressure difference of 20kpa, so it should be installed at the near end and uneasy at the far end.

Now you have an understanding of the principle of flow control valves. For the flow control valve, it has a lot of advantages, and its use has brought a lot of convenience to our lives, so you can learn more about it.

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