Compact and Union Ball Valves: Efficient Fluid Control Solutions?

As a key component for controlling water sources, ball valves provide a reliable and efficient solution for regulating the flow of various fluids. Whether in construction, industrial pipelines or agricultural irrigation, ball valves have a wide range of applications.

What is a ball valve?

A ball valve is a mechanical device used to control the flow of fluids (mainly liquids and gases) in a pipeline or system. Its name comes from the spherical occluder inside the valve body, which is the main flow control element. By turning the valve handle or actuator, the sphere can be positioned in different positions to allow or impede the passage of fluid. Ball valves are known for their quick operation, durability and ability to withstand high-pressure environments.

Classification of Ball Valves

Based on their structure, ball valves can be divided into the following categories:

One-piece Ball Valves: also known as Compact ball valves.

1.1 ERA Compact Ball Valves

Union Ball Valves

1.2 ERA Single & True Union Ball Valves

According to the use, ball valves can be divided into:

Check Valves

1.3 ERA Check Valves

Foot Valves

1.4 ERA Foot Valves

Butterfly Valves

1.5 ERA Butterfly Valves and Flanges

ERA’s Compact & Union Ball valves

Next, we'll introduce a few of the most popular ball valves currently available in ERA company:

1. COMPACT BALL VALVE : Compact ball valve is a commonly used control valve, which mainly consists of components such as valve body, handle, and valve ball. The valve body is equipped with inlet and outlet pipelines, and there is a spherical valve core inside. The handle is used to control the movement of the valve core. When the handle rotates, the valve core also rotates, thereby controlling the direction and flow rate of fluid in the valve.

2. SINGLE UNION BALL VALVE : Adopting a Type II structural design, it has a single-sided control function and can be used for medium pressure and flow applications.

3. TRUE UNION BALL VALVE : It also adopts a Type II structural design, but has a dual sided ball valve function, suitable for higher pressure and flow situations.

These valves are commonly used to regulate flow in liquid and gas pipelines.

The term "ⅡSINGLE UNION BALL VALVE" refers to a valve with only one port, allowing fluid to pass through in one direction and close off in the other.

A "ⅡTRUE UNION BALL VALVE" has two ports, enabling control of fluid flow in both directions and providing enhanced control performance.

Features of Compact & Union Ball valves:

Compared with other ball valves, the advantage of the compact ball valve lies in its uncomplicated structure and easy operation, making it suitable for basic fluid control tasks.The installation process is straightforward, the construction is uncomplicated, and maintenance is hassle-free.

The Ⅱ single union ball valve is suitable for situations where only one fluid needs to be controlled, such as water flow or air flow, without the need to control the direction change.

The Ⅱ true union ball valve is suitable for scenarios wheretwo fluids need to be controlled at the same time, suitable for applications requiring bidirectional flow control and prevention of reverse flow.

Structure :

1. COMPACT BALL VALVE ：

1. Body : PVC,CPVC,PP

2. Seat Seal : TPE,PTEE

3. O-Ring : EPDM,FPM(NBR)

4. Ball : PVC,CPVC,PP

5. Handle : ABS

6. Cap : ABS

2. Ⅱ SINGLE UNION BALL VALVE :

1. EndConnector : PVC,CPVC,PP

2. CarrierO-Ring : EPDM,FPM(NBR)

3. UnionNut : PVC,CPVC,PP

4. SealCarrier : PVC,CPVC,PP

5. Ball : PVC,CPVC,PP

6. Body : PVC,CPVC,PP

7. SeatSeal : PTEE

8. O-Ring : EPDM,FPM(NBR)

9. Stem : PVC,CPVC,PP

10. Stem O-Ring : EPDM,FPM(NBR)

11. Handle : ABS

3. Ⅱ TRUE UNION BALL VALVE :

1. Stem : PVC,CPVC,PP

2. Handle : ABS

3. Stem O-Ring : EPDM,FPM(NBR)

4. UnionNut : PVC,CPVC,PP

5. EndConnector : PVC,CPVC,PP

6. Body O-Ring : EPDM,FPM(NBR)

7. Ring : EPDM,FPM(NBR)

8. Body : PVC,CPVC,PP

9. Ball : PVC,CPVC,PP

10.    SeatSeal: PTEE

11. Seat Carrier : PVC,CPVC,PP

12. CarrierO-Ring : EPDM,FPM(NBR)

Comparison of ERA’s with ball valves from other manufacturers

1. Raw Materials

ERA:

EPDM : Used for O-rings, EPDM offers excellent electrical insulation, chemical resistance, and impact elasticity. It also provides resistance to acids and alkalis, has low specific gravity, and is highly resistant to ozone, UV, weathering, and aging.

PVC (Polyvinyl Chloride): ERA uses high-quality PVC material for valve bodies and fittings, which offers excellent corrosion and compression resistance and is lightweight. This material also has good chemical resistance and mechanical strength. ERA's self-compounded formulation is NSF certified, and products manufactured from ERA-developed formulas have received over 60 prestigious international certifications.

Other factories:

NBR : Used for O-rings, although it performs well in some applications, it has several drawbacks, including poor cold resistance, poor ozone resistance, lower strength and elasticity, poor acid resistance, poor electrical insulation, and poor resistance to polar solvents.

PVC: Other manufacturers may use lower-quality PVC materials, resulting in reduced durability and reliability of valve bodies and fittings.

2. Scale of Production

ERA:

With 9 production bases nationwide covering most of China, ERA has a strong production and supply capacity of 1.6 million tonnes per year, which meets market demand and ensures timely delivery.

Other factories:

Most other factories have a smaller production scale and are concentrated in specific regions with limited supply chain coverage, which may lead to untimely delivery.

3. Product Quality

ERA:

ERA ball valves are of excellent quality, using high-quality materials and advanced manufacturing processes to ensure product durability and reliability.

A strict quality control system ensures that each batch of products meets high standards.

Other factories:

Product quality varies, and some factories may compromise on material selection and manufacturing processes, resulting in poorer product durability and reliability.

4. Quality Control Process

ERA:

ERA has a comprehensive quality inspection process. From raw material purchasing to finished products leaving the factory, each step undergoes strict quality inspection. Each ball valve produced by ERA passes a water pressure test before being packed and shipped.

Advanced testing equipment and technology are used to comprehensively test various performance indicators of the products to ensure stable product quality.

Other factories:

The quality inspection process in some factories is not strict enough and may omit or simplify testing steps in some parts, leading to hidden product quality problems.

Advantages of plastic ball valves over traditional copper or iron ball valves

(1)Good hygienic performance. No precipitation of heavy metals. It’s safer and healthier to use.

(2)Good corrosion resistance. The corrosion resistance of plastic valves is better than cast iron valves, steel valves, copper valves and stainless steel valves.

(3)More Light weight. Plastic valves are lightweight, about 1/3 of the valve for the metal. Therefore, plastic valves are easier to install and can reduce the installation load of the pipeline. In addition, the light weight can reduce transportation costs and installation costs.

(4)Longer service life. The service life of plastic valves is not less than 25 years, some of the structure of the valve can be maintenance-free.

(5)Smooth inner wall. The inner wall is smoother than valves which are made of metal and less prone to scaling. In the seasonal use of the system, they will not be adsorbed in the valve sealing parts because of some substances in the transport

medium, and affect the opening and closing operation when the valve is used again.

(6) More cost-effective. Relative to metal valves, plastic valves cost-effective, giving the user an increase in the choice of varieties of comparison.

The two valves in the figure were installed in the water pipeline copper products, the left figure is a copper ball valve, the right figure is a copper angle valve, it can be seen that the corrosion resistance of metal valves and resistance to adsorption performance relative to the plastic valves are relatively weak, cast iron valves are even more so.

Condition of copper valve after long service

ERA Valve Product Advantages：

1. Various product colors available.

2. Fully automatic installation of  compact ball valves and Each product is individually pressure tested to provide stable quality assurance.ERA has been equipped with 20 sets of automated injection molding systems for valves; 8 sets of automatic installation equipment for valves; and two automatic pressure-testing assembly lines.

3. Various international certifications.A total of 13 international certifications have been obtained, such as NSF, UPC, WATERMARK, WRAS and KITEMARK.

4. Self-built laboratories.Strong research team with two PhDs leading 250 research members; national technology center--Yonggao Research Institute can provide strong technical support.

Usages of different types of valves.

COMPACT BALL VALVE：

Switching Control: The primary purpose of compact ball valves is to control the on/off state of fluid flow, allowing or blocking the passage of media.

Flow Regulation: Some compact ball valves offer flow regulation capabilities by rotating the handle to control the valve opening and adjust the flow rate.

Diverting/Merging Flows: Multiple compact ball valves can be used to divert or merge fluid flows, managing media distribution between different pipelines.

ⅡSINGLE UNION BALL VALVE：

On/Off Control: Similar to regular ball valves, the primary function of single union ball valves is to control the on/off state of fluid flow.

Flow Regulation: Some single union ball valves also offer flow regulation capabilities.

Isolation: Can serve as isolation valves, separating a section of the piping system for maintenance or repair.

ⅡTRUE UNION BALL VALVE：

Facilitating installation and disassembly, the common ball valve is suitable for pipelines requiring frequent disassembly and maintenance.

Applicable scene：

COMPACT BALL VALVE：

Industrial Sector:

1,Petrochemical: Controlling various fluid media like oil, natural gas, and chemicals, including high-temperature, high-pressure, and corrosive media in pipeline systems.

2.Power Generation: Managing the flow of water, steam, and oil, commonly found in power plant cooling systems and boiler feedwater systems.

3.Metallurgy: Controlling the flow of water, gases, and molten metals, frequently used in steelmaking and iron smelting processes.

4.Food and Beverage: Managing the flow of water, juices, beverages, and alcoholic drinks, meeting food-grade hygiene standards.

5.Pharmaceutical: Controlling the flow of water, gases, and pharmaceutical products, fulfilling the high cleanliness requirements of the pharmaceutical industry.

Civil Sector:

1.Building Construction: Regulating the flow of water, heating, and air conditioning media, commonly used in building water supply, heating, and air conditioning systems.

2.Agricultural Irrigation: Controlling irrigation water flow for precise irrigation.

SINGLE UNION BALL VALVE：

1.Petrochemical: Controlling corrosive media, high-viscosity media, or media requiring frequent cleaning.

2.Pharmaceutical: Used in piping systems demanding high cleanliness and easy sterilization.

3.Food and Beverage: For piping systems requiring adherence to hygiene standards and ease of cleaning.

Civil Sector:

1.Building Construction: In water supply and heating systems requiring periodic maintenance.

2.Swimming Pool Equipment: Controlling the circulation and filtration of pool water.

TRUE UNION BALL VALVE：

Pipeline Systems Requiring Frequent Disassembly and Maintenance: The double union design enables easy and complete removal of the valve for cleaning, repairs, or replacement without dismantling any piping sections.

Space-Constrained Environments: Compared to flanged connections, union connections offer a more compact solution, making them ideal for applications with limited space.

Piping Systems Handling Flammable, Explosive, or Corrosive Media: True union ball valves offer enhanced safety as they can be easily isolated and replaced, minimizing the risk of leaks.

Industrial Sector:

Petrochemical: Controlling corrosive media, high-viscosity media, or media requiring frequent cleaning.

Pharmaceutical: Used in piping systems demanding high cleanliness and easy sterilization.

Food and Beverage: For piping systems requiring adherence to hygiene standards and ease of cleaning.

Civil Sector:

Building Construction: In water supply and heating systems requiring periodic maintenance.

Swimming Pool Equipment: Controlling the circulation and filtration of pool water.

To summarize, ball valves are a key component in fluid control, providing efficient and reliable solutions in a variety of areas such as construction, industrial pipework and agricultural irrigation. Simplex ball valves are easy to use and suitable for basic fluid control tasks, while unilateral and bilateral ball valves provide bi-directional flow control and easy maintenance.Ball valves manufactured by ERA stand out for their durability, high pressure resistance and excellent corrosion resistance, and the excellent performance and long-term stability of fluid management systems are guaranteed through quality materials and rigorous manufacturing processes. Welcome to visit our website for more product details.

1. Characteristics and advantages of fluid control

The fluid control solution adopts advanced technology and materials, and has the following characteristics and advantages:

Efficiency: The fluid control solution adopts advanced fluid dynamics design and optimization, which can achieve efficient fluid control and regulation, improve production efficiency and product quality.

Reliability: The fluid control solution adopts high-quality materials and manufacturing processes, has good corrosion resistance and wear resistance, and can operate stably for a long time in harsh working environments.

Precision: The fluid control solution adopts advanced sensors and control systems, which can achieve precise flow, pressure and temperature control to meet different process requirements.

Flexibility: The fluid control solution has a variety of structures and specifications to meet different application requirements, and can also be customized according to the special requirements of customers.

2. Application of fluid control in various fields

Energy field: Fluid control solutions are widely used in energy fields such as oil, natural gas, coal, etc., which can achieve efficient and reliable fluid control and regulation, and improve production efficiency and safety.

Petrochemical field: Fluid control solutions are used in all links of the petrochemical field, such as crude oil processing, refining, chemical production, etc., which can achieve precise flow, pressure and temperature control, and improve product quality and production efficiency.

Metallurgical field: Fluid control solutions are used in all aspects of the metallurgical field, such as steel production, aluminum production, etc., which can achieve efficient and reliable fluid control and regulation, improve production efficiency and product quality.

Food, medicine and papermaking fields: Fluid control solutions are widely used in food, medicine and papermaking fields, which can achieve precise flow, pressure and temperature control, improve product quality and production efficiency.

The working principle of the flow control valve is mainly to adjust the flow rate, pressure and other parameters of the fluid by changing the flow area between the valve core and the valve seat. Specifically, the flow control valve is based on the basic theories of fluid mechanics and mechanical mechanics. After receiving the control signal through the actuator, it pushes the valve core to produce displacement, thereby changing the flow area and realizing precise control of the fluid flow and pressure. ‌

There are many types of flow control valves, among which throttling control valves and pressure reducing control valves are two common types. ‌Throttling control valves‌ rely on the throttling effect to adjust the fluid flow, and adjust the flow area of the fluid when passing through the valve by changing the opening of the control element (such as the throttling orifice or the gap between the valve core and the valve seat), thereby realizing precise control of the flow. This type of control valve is particularly suitable for working conditions that require high flow accuracy, low flow rate and small pressure drop. ‌Pressure reducing control valves‌ adjust the fluid pressure by changing the gap between the valve disc and the valve seat or the cross-sectional area of the fluid channel. When the fluid passes through the valve, its pressure will change due to the change of the flow area or the cross-sectional area of the channel, and is often used in occasions where precise control of the fluid pressure is required.

Flow control valves are widely used in industry and construction. For example, in industrial heating systems, temperature sensors monitor system temperature in real time. Once the temperature exceeds the set value, the controller sends a command to the control valve. After receiving the command, the actuator drives the valve core to move, narrowing the valve opening, thereby reducing the flow of the heat medium and lowering the system temperature to the set range. In building water supply systems, pressure reducing control valves are often installed on water supply pipes to ensure stable water pressure for users on each floor.

Classification

1. Characteristics of small flow control valve

The so-called small flow control valve, as the name implies, is a control valve with very small flow capacity. The flow capacity of a valve is an indicator of the valve capacity under uniform conditions. In my country, it is expressed by the C value. It is defined as: when the valve is fully open, when the pressure difference before and after the valve is 1 kg/cm² and the medium density is 1 g/cm³, the amount of medium flowing through the valve per hour (m³/hour). For incompressible fluids, in a fully turbulent state (when the Reynolds number is large enough, for water Re>105; for air Re>5.5 ×10 4) In the formula: △p——pressure difference before and after the valve (kg/cm²) Υ——medium density (g/cm³) Q-medium flow rate (m³/hour) The United States and other countries use C values to express the flow capacity of the valve. The internationally recognized I, E, and C standards mainly related to electricity use Av values to express the flow capacity of the valve. The conversion relationship between the three is as follows: Cv = 1.17C Cv = 10 6 /24Av C = 10 6 /28Av The flow capacity of the valve depends only on the structure of the valve itself. When calculating the required valve flow capacity, it should be noted that the flow state in the valve will be very different when the medium is different or the flow conditions are different. In the case of small flow, especially when working under viscous fluid and low pressure, the main constraint of the fluid is often laminar flow or a mixture of laminar flow and turbulent flow. In laminar flow, the medium flow through the valve and the pressure difference before and after the valve are linearly related. In the mixed state of laminar flow and turbulent flow, as the Reynolds number increases, even if the pressure difference remains unchanged, the amount of medium flowing through the valve will increase. In the case of complete turbulence, the flow rate does not change with the change of the Reynolds number. Despite this, the selection of small flow control valves is still carried out using traditional methods and calculation formulas. However, the calculated value and the actual value deviate greatly. According to the information, when Cv = 0.01 or less, it is only a capacity indicator with reference significance. The actual flow capacity should be determined based on experience.

As the flow capacity decreases, the adjustable ratio of the valve will decrease. But at least it can be guaranteed to be between 10:1 and 15:1. If the adjustable ratio is smaller, it will be difficult to adjust the flow. When the valve is used in series, as the opening changes, the pressure difference before and after the valve also changes, so the working characteristic curve of the valve deviates from the ideal characteristic. If the pipeline resistance is large, the linearity will become a fast-opening characteristic and lose the adjustment ability. The equal percentage characteristic will become a linear characteristic. In the case of small flow, since there is little pipeline resistance, the above characteristic distortion is not large, and the equal percentage characteristic is actually unnecessary. From the manufacturing point of view, when Cv = 0.05 or less, it is impossible to produce an equal percentage side shape. Therefore, the main problem for small flow valves is how to control the flow within the required range. From the perspective of economic effect, users hope that a valve can be used for interception and regulation at the same time, which is now possible. But for regulating valves, the main purpose is to achieve flow control, and closing is secondary. It is wrong to think that the flow of small flow valves is very small and it is easy to intercept when closed. Foreign countries generally also have regulations on the leakage of small flow control valves. When the Cv value is 10-, the leakage of the valve is stipulated as: under 3.5 kg/cm. Air pressure, the leakage is less than 1% of the maximum flow.

2. Types of small flow control valves

Due to the advantages of pneumatic control valves such as inherent explosion-proof and reliable performance, pneumatic control valves are still the main type of control valves at home and abroad. In the past, the small flow control valves officially produced in China. The maximum operating pressure can reach 100 kg/cm², and the rated flow capacity C value can be from 0.05 to 0.0012. The valve seat aperture is 3 mm, the valve core is cylindrical, with one or several V-shaped grooves engraved on it, the valve stem stroke is 6 mm, and the valve has no matching positioner, so the control accuracy is poor. In recent years, my country has also introduced small flow control valves. The flow capacity is about 0.001, and the valve core is cylindrical with a notch. The working pressure is 300 kg/cm². The valve stem stroke is 7/16 inches. The valve core is conical. The valve has a top-mounted positioner from Moore. The above-mentioned valves are characterized by simple structure and light weight. The commonly used valve seat aperture is 1/8 to 1/4 inches (about 3.175A-6.35 mm), and the valve stem stroke is 1/4 to l/2 inches (6.35 to 12.7 mm). The flow capacity of this type of valve can be as small as 0.00006 or even smaller. Generally speaking, the cylindrical slotted valve core is better than the conical one in terms of characterization. It can obtain the design characteristics by changing the groove depth, but the latter has good adjustment flexibility because the fluid passing through the valve is distributed on the entire circumference of the valve core section. This type of valve is often used in places where the accuracy requirements are not very high. However, the capacity accuracy and the reproducibility of the characteristics are poor. The flow capacity of the valve depends mainly on the orifice diameter. For a 1/16-inch orifice, the theoretical Cv value is about 0.06, or just close to the upper limit of the small flow rate. To further reduce the flow rate, the valve core stroke must be fundamentally reduced or the orifice opening must be restricted.

Three types of short-stroke control valves

First, the valve core is an artificial sapphire ball. The valve seat is a hard metal orifice. The maximum stroke of the diaphragm can be adjusted by the screw on the top of the diaphragm head. The actuator has variable pneumatic feedback, so the flow capacity can be from 0.07 to 0.00007 (Cv value) corresponding to a signal pressure of 3 to 15 pounds per hour. Another form of short-stroke control valve can be used for high-pressure conditions. Its valve core is conical. The actuator's drive arm rotates the threaded valve stem through a rotating part to rotate an angle, thereby achieving the purpose of shortening the stroke. The pitch of the guide thread is 11 to 32 teeth per inch, the rotation angle of the rotating rod is generally 15 to 60°, and the valve core stroke is generally 0.02--0.005 inches (equivalent to 0.508 to 1.27 mm). Because the thermal expansion is different at different temperatures, the valve core will produce significant errors, so this valve is limited to use below 300"F. To ensure the accuracy of the valve position, the valve is equipped with a positioner.

IV. Requirements for valve core and valve seat under high pressure difference

For high pressure and small flow control valves, a series of problems caused by high pressure and high pressure difference must also be considered. For example, the actuator must have sufficient output force to overcome the unbalanced force of the medium, the strength of valve parts, and high pressure sealing problems, and the most critical is the material and processing of the valve core and valve seat. The causes of damage to the valve core and valve seat of high pressure control valves are very complicated, and the theories here are not exactly the same, but what generally attracts attention is the scouring phenomenon (also known as the velocity effect) caused by the movement of high-speed liquid (gas) flow relative to the valve core and valve seat and the cavitation phenomenon of liquid medium under high pressure difference. . The former is damaged in the form of scouring marks that are related to the streamlines, while the latter is in the form of sponge-like holes. In situations where cavitation occurs, if the valve core and valve seat materials are not properly selected, the valve will be scrapped in a few days or even a few months. To solve the cavitation problem, we should start with methods to avoid cavitation and materials that are resistant to cavitation. There are several ways to avoid cavitation. 1. Improve the design of the valve core and valve seat to give it a reasonable liquid flow velocity distribution and pressure distribution. For example, a small flow control valve uses a narrow channel valve core and valve seat. The valve core and valve seat holes have a very small taper, which is suitable for precise control of flow under constant upstream pressure conditions. Because this structure has the function of absorbing energy and reducing cavitation, it has been reported that it has been used under a pressure drop of 4200 kg/cm². 2. In If conditions permit, add gas to the liquid flow to partially or completely eliminate the low pressure area. 3. Use valves in series to reduce the pressure drop of each valve. 4. Make the pressure difference before and after the valve lower than the maximum allowable pressure difference that causes cavitation of the medium at the inlet temperature of the regulating valve. 5. When the medium works in the "flow open" state, the allowable pressure difference is more than three times greater than that in the "flow closed" state.