The swing type check valves function with various kinds of media that include liquids & gases. The most frequent applications of these valves are in fire fighting equipment, to prevent floods in sewage systems, mechanism of toilet flushing and so on. Read this article to know every little thing about swing type check valves.
What are Swing Type Check Valves?
Swing check valves are mounted along with a disc, the disc swings on a shaft or hinge. This disc swings the seat off to permit forward flow and when the flow gets stopped, the disc again swings onto that seat to obstruct the reverse flow. Swing type check valves are specially designed to avoid the medium from flowing back in the pipeline. When pressure touches zero, the swing check valve shuts off completely to prevent the backflow of fluid. Swing type check valves usually are automatic valves that are mostly used in pipelines where the medium flows in a single direction and permits the medium to flow only in one direction for avoiding accidents. Turbulence and pressure drops in the swing type check valve are very low. The swing check valves must be installed horizontally but if it is installed in a vertical direction keep in mind that the disc should not touch the stalling position wherein open position the disc gets stuck.
What is the working principle of swing type check valves?
The swing type check valves embrace the swing structure of the built-in rocker. The opening, as well as closing parts of the valve, are installed in the body of the swing valve. They never enter the valve’s body except for the sealing gasket & sealing ring. The chances of valve leakage are almost negligible as there are no leakage points present as a whole. In between the swing type check valve & valve clack, the swing arm connection acquires the spherical connection structure so that the clack can have freedom within 360 degrees of range. When a medium flows downstream, it rushes via valve flap & opens the swing valve, pressure at which the swing type valve opens is known as cracking pressure. The pressure of the medium on falling below the cracking pressure, swing valves automatically shuts off.
What are the features of swing type check valves?
There are many features of this valve. Here are a few important of them:
a) The complete structure is compact and quite simple which makes this valve’s appearance beautiful.
b) When the medium pressure of the swing type check valve gets below its cracking pressure, the swing check valve flap quickly closes, making the pressure of the water hammer very little.
c) Flap of the valve by using the mechanism of hanging lessens the leakage of each component in the body.
d) The medium’s flow in this valve is unhampered & it offers very low fluid resistance to the used medium.
e) The swing type check valve is extremely sensitive to little change in the pressure and this also offers a good kind of sealing.
f) It has a short disc stroke that makes the closing impact of the valve very low.
g) The swing type check valves have a long service life because the wear is very less, making the valve reliable.
What are the applications of swing check valves?
You can apply the swing check valve to different kinds of media such as steam, oil, water, strong oxidizing media etc. Mainly these valves are used in firefighting systems, chemical, petrochemical, power, fertilizer and other pipelines. They are also apt for clean media but not for media that contains solid particles. Swing check valves are never recommended where the medium’s flow is low or pulsating.
What kind of maintenance is needed for swing check valves?
One of the advantages of using swing type check valves is – it does not need much repairing and maintenance and lasts longer. Sometimes the valves can develop leaks when any foreign particles get stuck in between the seat and disc. It can lead to downgrading the function of swing valves.
> For preventing swing check valves from any damage try to keep it clean by regularly wiping off dirt and dust.
> Try to carry out intermittent inspection of the valves
> Always check for the leakages and replace them immediately when heavy leakage is detected.
> Try to check the signs of rust & wear and tear.
> Scrutinize the temperature and pressure of flowing fluid via the swing valves.
> Always try to ensure all the parameters are within the valve’s limit.
> When the valve gets replaced, always clean up the removed swing valve through overhauling & wash every part thoroughly with the help of hydraulic liquid.
> Check for scratches or wear & tear and if you find such then make it smooth and again assemble them back.
How to install a swing type check valve?
The swing type check valves are mounted in the vertical direction on the horizontal pipe when ships are completely opened. Before installation few points must be remembered:
> Separate the cover along with the foam plate at the ends of the valves.
> Take off the grease paper and remove the grease on the valve’s surface.
> Check the free movement of the swing type check valve
> It should be installed right in the direction of the mentioned flow arrow.
> While you install the valve, media flow should be very limited.
> Medium that will pass through the line must not consist of hard particles as it can destroy the sealing surface.
What important points to remember?
The swing check valves act as critical elements in some situations because the reverse flow can be extremely damaging, so it is needed that the check valves should be always detected with issues much before to avoid a shutdown of the pipeline.
So we hope you have come to know what swing type check valves are and everything about them. Swing check valves efficiently work to prevent reverse flow in your pipeline. These valves produce the very lowest pressure drop and their design is simple and hassle-free to maintain.