Floating Ball Valve
Floating Ball Valve
※ Fire Safe Design
※ Anti Static Device
※ Anti Blow Out Stem
※ Size Range: NPS 2 to NPS 8
※ Class Range: 150LB to 2500LB
※ Floating Ball Valve Manufacturer & Supplier
Introduction
Valves are an integral part of any pipeline system, which is used to control and regulate the flow of system fluid. When it comes to quick shut-off operations of fluids flowing through pipelines and other piping systems in the gas, oil, water, and other industries, a floating ball valve is one of the most common names.
One of the most critical design aspects of any valve type is to ensure tight sealing and smooth operation throughout the lifespan. Most floating ball valve manufacturers have focused on these design aspects and offer valves in different configurations and sizes.
If you’ve ever wondered, “What is a floating ball valve?” then keep reading because we’ve broken everything down for you. We will explore the construction and operation of floating ball valves in-depth and the variants, strengths, and drawbacks, and their vast range of applications.
What Is A Floating Ball Valve?
The term “floating ball” refers to the hollow, ball-like sphere that “floats” freely within the valve’s body, which gets compressed between the two flexible seats when the valve is operated. In simple words, the ball remains suspended in the fluid without any support structure and is kept in place only by the valve seat.
Floating ball valves provide a bi-directional airtight seal, making them ideal for controlling liquid flow such as oil, gas, steam, and water. These valves are normally used in pipelines with low to medium pressure but can even be customized for high-pressure operations.
According to most floating ball valve manufacturers, these valves have a compact design compared to other isolating valves, making them ideal for use when space is an issue. Also, being lightweight and economical, they are preferred in many industrial applications.
Construction Of Floating Ball Valve
The basic construction of a floating ball valve is the same as a traditional ball valve which includes a valve body, hollow ball, stem, and an operating handle (manual or automatic). The major design difference is in support of the ball inside the valve body.
Here, the ball is suspended in the medium it regulates by a cup-like seat typically constructed of thermoplastics. The ball itself has a hole through which liquids pass freely when correctly aligned with both ends of the valve.
The cupped seats support the floating ball, creating an airtight seal between the valve body and the ball. The seat design is unique as it provides reliable sealing even in the reverse direction and automatically releases the exerted pressure.
The stem is connected to the top of the ball, which allows the ball to rotate a quarter turn (90 degrees). In addition, it will enable some lateral movement of the ball when the upstream pressure is exerted on it. This tiny lateral movement forces the ball against the downstream seat, improving the valve’s leak tightness.
Floating Ball Valve: Working
The floating ball valves, similar to any ball valve design, are operated by a shaft, or stem, attached to the top of the ball that turns it 90 degrees (a quarter turn). As the ball rotates, the port is covered or uncovered, allowing or blocking the flow of media.
The stem is freely linked to the ball such that the pressure of the flow presses the ball against its downstream seat as it turns on its axis, creating a tight seal. This design feature of the valve allows it to operate in either direction of fluid flow.
Classification Of Floating Ball Valve
Floating ball valves are generally classified into three types according to the design of the housing.
One-piece Floating Ball Valve
The body is single forged or cast steel in this valve design, which houses all the moving valve parts. These valves are employed in smaller applications because they are compact and least expensive.
Two-piece Floating Ball Valve
This type of valve has two housing pieces cast together or forged where one piece is always larger than the other, and the moving parts are housed in the larger piece. Such valves are especially suitable for working conditions such as high temperature and high pressure.
Three-piece Floating Ball Valve
The three-piece floating ball valve has three sections from left to right, typically comprising a body and two bonnets. This is the most expensive valve subtype and tends to be larger than other valve types.
Floating Ball Valve: Technical Specifications
- Size Range : NPS 2 to NPS 8
- Class Range: 150LB to 2500LB
- Design Standard : ISO 17292 / API 608 / API 6D
- Fire Standard : API 607
- End Connection : Flanged; BW; Threaded
- Operation : Manual Lever / Pneumatic / Electrical
Floating Ball Valve: Special Features
Over a period of time, floating ball valve manufacturers have adopted various design features to enhance the working and safety standards of these valves. Some of the salient features include:
- Integral locking device to stop unintentional operation.
- Fire-safe design as per API 607 standards.
- Antistatic design feature to make it suitable for flammable and explosive media.
- Tight sealing to ensure zero leakage.
- Blowout-proof stem design to ensure positive stem retention.
Sealing Arrangement in Floating Ball Valve
Sealing arrangement in a floating ball valve is the key to its effective performance regardless of the material used. So, let us look at some basic seal types used by most floating ball valve manufacturers.
§ Soft Seal
- The valve seat is embedded in the valve body by a specific press on both the upstream and downstream sides.
- Mostly used for applications with working conditions below 150° C.
- Flexible operation and reliable sealing.
- Material: PTFE, RPTFE, NYLON, PPL, PEEK, etc.
§ Metal Hard Seal
- A seat assembly is installed on the valve’s upstream side, and the sealing surface is coated with carbide.
- The seat on the valve’s upstream side provides the required initial sealing specific pressure for the valve, while the seat on the valve’s downstream side performs the main sealing.
- Mainly used in applications with working conditions that include high temperature and the presence of particles, dust, slurry, etc.
- Reliable sealing even at high temperature and high pressure.
- Material: Stellite cemented carbide.
§ Composite seal
- Two valve seat components are provided on both the upstream and downstream sides of the valve. Each valve seat component is formed by a valve seat, valve seat ring, and gasket.
- Metal seal is the main seal that cuts off the majority of the medium and prevents particle contaminants from accessing the soft sealing surface.
- Soft seal is the secondary seal used to block the medium completely.
- Mainly used in applications involving media with particles, dust, slurry, and others under normal temperature (below 150℃).
- Long service life and reliable sealing type.
- Material: Type of rubber.
Advantages of Floating Ball Valve
Let us now look at some advantages of floating ball valves.
- Lightweight and compact design
- Cost-effective
- Customizable
- Little flow resistance
- Tight and reliable sealing
- Easy operation with a fast shutter speed
Disadvantages of Floating Ball Valve
There are certain limitations to the use of floating ball valve, which includes
- Complete reliance on downstream seating.
- High upstream pressure makes operation difficult.
- Sealing surface can easily get damaged.
Applications Of Floating Ball Valve
There is a wide range of industries and environments in which floating ball valves are used. This includes
- Gas processing industry
- Petrochemical industry
- Chemical and natural gas industries
- Offshore and onshore oil and gas wells
- Transmission lines and storage facilities
- Other industries where gas or liquids are transported via piping systems.
Summary
As discussed in the article, floating ball valves are one of the most widely used in industrial applications. Even though these valves are generally suitable for low to medium pressure applications, floating ball valve manufacturers can customize them for high-pressure operations.
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