Ball Valve Working Principle
Rotating the sphere 90 degrees on the bore axis and turning the bore (s) to the passage open or closed, with one or more holes in the middle on a The shaft is mostly elastomer (may also be metal) between the two seals, which are cut, opened, and perform their functions.
If possible, work fully open or fully closed. For precise flow control, they are not suitable.
Ball Valve Advantage and Disadvantage
Advantages
- Fluids pass through them freely and comfortably.
- Pressure drops are shallow, especially in 2-way valves. The arm is one of the valve types with the lowest flow resistance.
- It is easy to use.
- They can use with actuators.
- Gaseous fluids can also use with them. In particular, elastomer seals can achieve “0 leaks”.
- The valve can be operate from both sides.
Disadvantages
- Due to their structure, their weight is high.
- The more the nominal size grows, the more expensive they become.
- A dead volume exists between the sphere and the body cavity.
- Sudden openings and closings can cause ram blows.
- Based on the temperature resistance of the elastomer, valves with elastomer seals have relatively low operating temperatures
Ball Valve Types
According to the through-hole size
Full bore valves: Through-hole valves: valves with a diameter that is very close to the nominal size, expressed in mm, providing smooth flow without turbulence.
Narrow (reduction) throughput valves: With a diameter smaller than the nominal size of the valve, through-hole valves are generally given for smaller nominal sizes than the nominal size of the valve.
According to the flow direction
The rough hole of the full bore valves is very close to the inner diameter of the pipe to which they are connect, so they show a very low flow resistance when fully open, and the system ensures that the total resistance factor remains low.
Smaller spheres can use to make narrow-through valves lighter and cheaper. While resistance factors are higher than the full bore, full bore valves can be easily use in places where there aren’t a lot of valves, as they remain lower than other types of valves.
Disadvantages:
With narrow pass valves, turbulence is form, and the valve resistance factor increases as the flow follow a narrowing and then expanding path. Due to this increase, pump head height and energy consumption will increase in parallel with the increasing number of valves in the system.
- 2 way
- 3 way
- 4 way
The most commonly used valves are two-way valves. In 2-way valves, holes (holes) are drille perpendicular to the linear transition hole perpendicular to the flow axis to produce 3- and 4-way valves that are use as distribution or mixing valves depending on the type of connection to the installation.
According to the sphere bearing type
Floating ball
On both sides of these valves, the sphere is surrounded by sealing gaskets.
During the valve’s close position, the opening-closing shaft is connect in a channel, which allows the ball to move on the flow axis, and the fluid pressure pushes the ball towards the gasket on the opposite side, causing a positive seal.
Bearings of this type can use up to nominal sizes of DN 100-125, but the valve varies depending on the rated pressure. The valves are use for applications with low pressure-temperature values.
Guided ball (trunnion ball)
The axis of the sphere is perpendicular to the flow axis. The valves mount directly to the shaft from the bottom and the top.
The lower and upper bearings provide the pressure force on the closed valve transition section, not the seals.
In applications with high pressure-temperature values, they are using. If we examine a DN 25, full bore PN 25 valve with a 150 mm through-hole diameter, if the fluid pressure is P = 20 Bar, the pressure force applied to the ball in the closed valve;
F = [(3.14 x 152) / 4] x 20 = 3.532 kgf has reached a fairly high dimension, and this force can only be deformed by elastomer seals.
Reinforce plate spring: By aligning the sealing gaskets with the sphere surface, in the direction of fluid arrival, the seal adheres to the sphere surface and a positive contribution is made to the seal.
Aira Euro Automation is a ball valve manufacturer in India. We have a wide range of industrial ball valves, we also export our product to more than 20 countries around the world.
