Today Professor Jim talks about check valves. Hello class and welcome to another addition of Industrial Valco University, today we are going to talk about the Swing Check Valve...The main reason for the check valve is to prevent back flow.
: Preventing back flow means that water or the media can only flow in 1 direction.
the swing check is literally found in every industry where a pump is located… thus if your heavy in the plumbing world, you will want to be familiar with this valve.
: The swing check is the one of the most basic designs of valves with only 2 or 3 moving part. The swing check valve has a disk that acts as a trap door over the seat. The disc is anchored to a hinge pin with a hanger arm so that the hanger disk assembly pivots around the pin. The hinge lets the disk and holder swing away from the seat.
Turbulence and pressure drop in the Valve are very low; however, special care has to be taken on how the valve is installed
VIDEO When water flows through a check valve. It pushes against the disk. This flow pushes the disk away from the seat and up against the top of the valve. Swing checks can only be installed with the flow horizontal or vertical upward flow only. When properly installed, the valve will close automatically. This is a result of the weight of the disc closing the valve. When water tries to flow backward gravity pulls the disk down around the seat. The pressure of the backwards flow helps provide a firmer seal against the seat.
To work properly the valve must be installed properly so the disk naturally falls against the seat. How is this done….. aha!
Every valve will have an arrow that indicates the direction of the flow through the valve.
also , They should never be installed on their sides or upside down. Which leads us to a special check valve edition of “did you know”
Did you know:__ did you know that the song from former __NWA Rapper IceVube’s first solo album, Check yo self contrary to popular opinion, is not actually about check valves at all. It is actually about making sure you call out an individual who made a grave mistake, so they canthink about what they have done and atone for their lack of judgement.
So an example of this would be, say you were to buy a Swing Check from anyone but Industrial Valco, I would then say, you should probably check yo self before you wreck yourself…. OK lets talk about the advantages and disadvantages of the check valve.
Advantages:
• Low pressure drop
• Only 3 moving parts
• Simple to maintain and repair
Disadvantages
• Does not seal at low pressures
• Requires a backflow to close valve quickly
• Most valves are not pigable
• Susceptible to Water Hammer
lets talk quickly about what water hammer is: In viscous (VISCUS) or slow moving liquid or fluids the valve may close slowly.
As a result, a back flow may occur. The back flow will aid the valve in closing quicker; however, this can lead to a water hammer situation. Water hammer (or, more generally, fluid hammer) is a pressure surge or wave resulting when a fluid in motion is forced to stop or change direction suddenly Water hammer commonly occurs when a valve is closed suddenly.
This pressure wave can cause major problems, from noise and vibration to pipe collapse. Ok lets review what we learned today.
The swing check is the one of the most basic designs of valves with only 2 or 3 moving parts. When water flows through a check valve. It pushes against the disk. This flow pushes the disk away from the seat and up against the top of the valve. When properly installed, the valve will close automatically. This is a result of the weight of the disc closing the valve. When water tries to flow backward gravity pulls the disk down around the seat. The pressure of the backwards flow helps provide a firmer seal against the seat.
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