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Description:
Ball valve, known as shut-off valve, is an equipment to allow flow control, utilized as a hollow, perforated and pivoting ball to control the liquid flowing through it. It is an economical option to other valves. It opens when the hole of the ball is aligned with the inflow port, and closes when it is pivoted 90 degrees by the valve handle, thereby preventing flow. The handle of the device is flush with the water flow when it is opened, and perpendicular to the water flow when it is closed, making it easy to visually confirm the valve status. The closed position 1/4 turn can be clockwise or counterclockwise. Low pressure ball valves are in a leading position in the valve industry and have a wide range of applications. The quarter turn valve control makes it easy to operate and requires only little maintenance. It allows maximum flow with minimum pressure drop. Low pressure ball valves are mainly used in critical applications that provide a tight sealing to control the system flow. They are highly used for the smooth operation of water, oil and gas systems. |
Brand:
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CATALOGUE
Different Types of Low Pressure Ball Valves
Product Information of Low Pressure Ball Valves
1. What are the types of ball valves?
There are three different types of ball valve, which are:
(a) 1 piece ball valve
(b) 2 piece ball valve
(c) 3 piece ball valve
A low pressure ball valve can be categorized into two types of design, full bore ball valve and reduced bore ball valve according to the formed channel flow. The 1-piece ball valve is reduced bore, while the 2-piece ball valve is generally known as the standard bore (full bore). The full bore ball valve has an oversized ball, which allows the size of the hole on the ball the same as for pipe applications. Besides, the reduced ball valves are the valves that close the part to open to control the flow, and its flow area is smaller than the inner diameter of the pipe. Thus, the usage of the ball valve commonly in switches and circuits for general hydraulic applications. It is customizable and can be easily used with other tools.
There are three different types of ball valve, which are:
(a) 1 piece ball valve
(b) 2 piece ball valve
(c) 3 piece ball valve
A low pressure ball valve can be categorized into two types of design, full bore ball valve and reduced bore ball valve according to the formed channel flow. The 1-piece ball valve is reduced bore, while the 2-piece ball valve is generally known as the standard bore (full bore). The full bore ball valve has an oversized ball, which allows the size of the hole on the ball the same as for pipe applications. Besides, the reduced ball valves are the valves that close the part to open to control the flow, and its flow area is smaller than the inner diameter of the pipe. Thus, the usage of the ball valve commonly in switches and circuits for general hydraulic applications. It is customizable and can be easily used with other tools.
1 PC Ball Valve
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2 PC Ball Valve
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3 PC Ball Valve
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2. Specification on different types of ball valves?
(a) 1-piece Ball Valve
This type of ball valve consists of a valve body and end connection made of a single piece of material. The ball valve has a solid cast valve body, which can significantly reduce the risk of leakage. In this type structure, the low-pressure ball valve trim and the seal are inserted through one end connection. The port size of the ball valve of this design is not equal to the pipe size, as the flow through the valve is one pipe size smaller than the valve’s pipe size resulting in the flow area being smaller than the pipe. As the flow discharge remains constant and is equal to the area of flow, the velocity increases with reduced area of flow.
Following equation explained the flow of the reduced port:
A1V1= A2V2
Where,
A = Area of flow
V = Velocity
(b) 2-piece Ball Valve
This type of ball valve is the most general used type of ball valve structure. It has two separate parts, which are either threaded or connected by bolts and flange components. A ball valve constructed in this way has one part including an end connection and a valve body, and the second part is installed into the first part to hold the valve trim in place and provide a second end connection. The low-pressure ball valve designed in this way maintains the possibility of leakage at the two-piece connection, but if the internal parts need to be replaced, it also allows the valve to be disassembled.
(c) 3-piece Ball Valve
A 3-piece ball valve refers to the ball valve which consists of three pieces (including two end caps and a valve body). The end caps are connected to both sides of the pipeline by threads, welding, or flanges. The ball valve with this structure is specifically designed to separate the connection part of the valve assembly from the rest of the valve body. This ball valve can be a valuable option because it can prevent the production line from shutting down if maintenance is required.
(a) 1-piece Ball Valve
This type of ball valve consists of a valve body and end connection made of a single piece of material. The ball valve has a solid cast valve body, which can significantly reduce the risk of leakage. In this type structure, the low-pressure ball valve trim and the seal are inserted through one end connection. The port size of the ball valve of this design is not equal to the pipe size, as the flow through the valve is one pipe size smaller than the valve’s pipe size resulting in the flow area being smaller than the pipe. As the flow discharge remains constant and is equal to the area of flow, the velocity increases with reduced area of flow.
Following equation explained the flow of the reduced port:
A1V1= A2V2
Where,
A = Area of flow
V = Velocity
(b) 2-piece Ball Valve
This type of ball valve is the most general used type of ball valve structure. It has two separate parts, which are either threaded or connected by bolts and flange components. A ball valve constructed in this way has one part including an end connection and a valve body, and the second part is installed into the first part to hold the valve trim in place and provide a second end connection. The low-pressure ball valve designed in this way maintains the possibility of leakage at the two-piece connection, but if the internal parts need to be replaced, it also allows the valve to be disassembled.
(c) 3-piece Ball Valve
A 3-piece ball valve refers to the ball valve which consists of three pieces (including two end caps and a valve body). The end caps are connected to both sides of the pipeline by threads, welding, or flanges. The ball valve with this structure is specifically designed to separate the connection part of the valve assembly from the rest of the valve body. This ball valve can be a valuable option because it can prevent the production line from shutting down if maintenance is required.
3. Benefit of using Low Pressure Ball Valve?
The easy operation, maintenance and versatility of the ball valve make it widely used in industry, supporting pressures up to 1,000 bar (100 MPa; 14,500 psi) and temperatures up to 752 °F (400 °C), depending on the design and materials used. The size is usually between 1/4" inch to 4” inch. The valve body is made of metal, stainless steel, plastic or metal plus ceramic; the floating ball is usually chrome-plated to improve durability.
Disadvantage of ball valves is that when used to control water flow, it collects water in the center cavity when it is in the closed position. In situations where the ambient temperature is below freezing, the sides may crack due to expansion associated with ice formation. In this case, some insulation or heating tape can usually avoid damage. The other alternative for cold climates is the “antifreeze ball valve”. This type of ball valve is equipped with a freezing plug on the side, so when freezing occurs, the freezing plug ruptures, acting as a “sacrifice” failure point and making repairs easier. It is not necessary to replace the entire valve, just install a new freeze plug.
- Ball valve is durable, performs well after multiple cycles;
- It is reliable, and can be safely closed even after long periods of non-use when it is used under the right conditions. Also, the high in durability of ball valve is less prone to damage and corrosion than other types of valve.
- It is an excellent choice for shutoff and control applications, where it is generally more popular than gate and globe valves, however in throttling applications, it lacks fine control over these alternatives.
The easy operation, maintenance and versatility of the ball valve make it widely used in industry, supporting pressures up to 1,000 bar (100 MPa; 14,500 psi) and temperatures up to 752 °F (400 °C), depending on the design and materials used. The size is usually between 1/4" inch to 4” inch. The valve body is made of metal, stainless steel, plastic or metal plus ceramic; the floating ball is usually chrome-plated to improve durability.
Disadvantage of ball valves is that when used to control water flow, it collects water in the center cavity when it is in the closed position. In situations where the ambient temperature is below freezing, the sides may crack due to expansion associated with ice formation. In this case, some insulation or heating tape can usually avoid damage. The other alternative for cold climates is the “antifreeze ball valve”. This type of ball valve is equipped with a freezing plug on the side, so when freezing occurs, the freezing plug ruptures, acting as a “sacrifice” failure point and making repairs easier. It is not necessary to replace the entire valve, just install a new freeze plug.
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4. How to measure a ball valve?
The size of the low pressure ball valve is usually from 1/4" to 4". Various applications require low pressure ball valves of various diameters. Low-pressure ball valves are made of carbon steel, stainless steel and brass. Stainless steel (SS316) is used as the standard material for low-pressure ball valves due to its strong corrosion resistance. The low pressure ball valve can easily withstand working pressures up to 2000 PSI, and is mainly suitable for a temperature range of -29°C to 150°C. The figure below shows how the working pressure is affected by the ambient temperature. The higher the temperature (°C), the lower the pressure can withstand. |
Low Pressure Ball Valve Pressure & Temperature Rating
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5. How to install a ball valve?
A proper installation is important to the entire system, it can prevent damage and fluid control systems to malfunction.
Step 1: Clean up and remove all kinds of foreign objects on the pipeline before installing the low-pressure ball valve.
Step 2: Ensure the connecting pipes on both sides of the valve are aligned correctly.
Step 3: Make sure that the two sections of the pipeline match in one system flow direction as the low-pressure ball valve unit cannot adsorb any gaps in between the connection. Any deformation or unequal pipeline will affect the tightness of the connection, the function and capacity of the valve. It will even cause rupture.
Step 4: If the pipeline section does not have proper support connection, it should be temporarily fixed with other equipment to prevent unnecessary internal or external pressure on the low-pressure ball valve.
Step 5: Apply thread sealant when making connections.
Step 6: Check the tightness of the connection again to ensure the high performance of the valve.
A proper installation is important to the entire system, it can prevent damage and fluid control systems to malfunction.
Step 1: Clean up and remove all kinds of foreign objects on the pipeline before installing the low-pressure ball valve.
Step 2: Ensure the connecting pipes on both sides of the valve are aligned correctly.
Step 3: Make sure that the two sections of the pipeline match in one system flow direction as the low-pressure ball valve unit cannot adsorb any gaps in between the connection. Any deformation or unequal pipeline will affect the tightness of the connection, the function and capacity of the valve. It will even cause rupture.
Step 4: If the pipeline section does not have proper support connection, it should be temporarily fixed with other equipment to prevent unnecessary internal or external pressure on the low-pressure ball valve.
Step 5: Apply thread sealant when making connections.
Step 6: Check the tightness of the connection again to ensure the high performance of the valve.
6. How will the ball valves go failure?
The low-pressure ball valve is operated extensively in a partially opened state, the result of improper valve selection and/or operational error may cause erosion and corrosion damage. According to a research Engineering Failure Analysis (2019), written by Moses, Haider and Hensaw, the authors indicate the factors that cause functional failure of a ball valve.
1. General fluid and solid particle Erosion
The erosion impact is minimal when used in on/off condition. When it is fully opened, the fluid flows through the valve almost unimpeded, and the erosion rate is similar to that of a straight pipe; while when it is fully closed, no fluid flow thus no erosion can be caused. However, erosion can occur when a ball valve is operated in a partially opened state. This is because water enters the partially opened valves, particles suspended in the fluid can erode the upstream edge of the ball. The concentrated area of high speed flow continues until it reaches the inner edge of the ball. The combination of high speech and sharp changes in the fluid direction produce rapid erosion.
2. Abrasion
The existence of the thin nickel layer is to protect the ball from wear at the sealing interface during the rotation of the ball, so as to maintain a better seal. Nonetheless, this protective layer is not sufficient to avoid sand particles from scratching the ball surface. It is different from the channels formed by fluid erosion, the channels formed by these scratches tend to be darker and rougher in appearance because of the corrosion that is not quickly removed by the fluid.
3. Cavitation
The static pressure in the valve may be lower than the water vapor pressure during throttling, resulting in rapid vaporization and bubble formation. When the fluid pressure increases above the vapor pressure, the bubbles will burst and emit tiny shock waves into the fluid. The damage caused by these shock waves is called cavitation.
The low-pressure ball valve is operated extensively in a partially opened state, the result of improper valve selection and/or operational error may cause erosion and corrosion damage. According to a research Engineering Failure Analysis (2019), written by Moses, Haider and Hensaw, the authors indicate the factors that cause functional failure of a ball valve.
1. General fluid and solid particle Erosion
The erosion impact is minimal when used in on/off condition. When it is fully opened, the fluid flows through the valve almost unimpeded, and the erosion rate is similar to that of a straight pipe; while when it is fully closed, no fluid flow thus no erosion can be caused. However, erosion can occur when a ball valve is operated in a partially opened state. This is because water enters the partially opened valves, particles suspended in the fluid can erode the upstream edge of the ball. The concentrated area of high speed flow continues until it reaches the inner edge of the ball. The combination of high speech and sharp changes in the fluid direction produce rapid erosion.
2. Abrasion
The existence of the thin nickel layer is to protect the ball from wear at the sealing interface during the rotation of the ball, so as to maintain a better seal. Nonetheless, this protective layer is not sufficient to avoid sand particles from scratching the ball surface. It is different from the channels formed by fluid erosion, the channels formed by these scratches tend to be darker and rougher in appearance because of the corrosion that is not quickly removed by the fluid.
3. Cavitation
The static pressure in the valve may be lower than the water vapor pressure during throttling, resulting in rapid vaporization and bubble formation. When the fluid pressure increases above the vapor pressure, the bubbles will burst and emit tiny shock waves into the fluid. The damage caused by these shock waves is called cavitation.
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