May. 27, 2024
Check valve failures can stem from improper installation methods, inadequate maintenance practices, and insufficient research before application.
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Such failures impede proper valve functioning and may lead to damage to pipe systems, pumps, and well equipment.
Check valves, also known as non-return valves, facilitate fluid flow in a single direction, preventing the reverse flow (backflow) in the applied system.
Consequently, a check valve failure in a well might result in fluid flowing back into the well.
Preventing check valve failures necessitates correct installation, regular testing for early detection of potential issues, and proper maintenance.
This discussion delves into the testing, installation, and assembly of check valves, addressing common failures, symptoms, causes, and solutions.
Discovering symptoms of a bad check valve is crucial to preventing leaks.
Incorrect installation, insufficient maintenance, and issues like reverse flow or damaged components can contribute to leaks.
Recognizing these symptoms enables timely intervention and ensures the proper functioning of check valves in fluid systems.
Selecting the appropriate check valve for the application and following the manufacturer's guidelines during installation can prevent leaks.
Regular inspection and cleaning of check valves are crucial to prevent debris buildup and extend the valve's lifespan.
Excessive reverse flow can cause wear and tear on the valve, leading to eventual leaks.
Elevated temperatures can accelerate valve wear and reduce the effectiveness of the seal.
Excessive wear, tear, or improper installation can result in leaks from the stem.
Improper installation or wear and tear of the seat seal can lead to leaks.
Over time, fasteners can loosen, causing leaks around the valve.
Gaskets that become damaged or worn out can contribute to leaks.
Solid particles trapped in the valve can obstruct the flow and cause leaks.
To address check valve leaks, regular maintenance, debris removal, and prompt replacement of damaged components are recommended.
If issues persist, replacing the entire valve may be necessary.
Identifying and fixing check valve problems is crucial for optimal performance. Here are solutions to common issues:
Replace worn-out components like the disc, seat, spring, or gasket to prevent leaks.
Reduce reverse flow to prevent valve wear and tear.
Apply lubrication to reduce friction, enhancing the valve's service life.
If issues persist, consider replacing the entire valve.
It's crucial to adhere to the manufacturer's instructions for installation and maintenance, ensuring proper function and preventing damage to the valve or the system.
Regular inspections and cleaning further contribute to leak prevention and overall system health.
Related links:LEFLOW Product Page
Common check valve problems, such as incorrect installation or wear and tear, can lead to leaks.
Proper installation, regular maintenance, and component replacement address these issues.
Following manufacturer guidelines is crucial to ensure optimal check valve performance, preventing damage and extending the system's lifespan.
(Mechanical)
(OP)
23 Apr 04 09:18
I have an 8" check valve that I need to replace that is in the vertical plane 11" from the discharge of a gpm pump. We have replaced one in the past with another swing type check valve and it now makes the awfullest beating and banging noise when the pump is running. Since the swing check valve relies on gravity (weight of disk) to shut off, I believe that sudden surges in flow is causing the disk to relax and slam back against the inside of the valve since gpm of water discharged from a pump is pretty turbulent. I don't believe we have a water hammer problem, but I could be wrong. What I'm looking at replacing the current valve with is an APCO Series 600 Globe Style Silent Check Valve. To fit in place of our existing valve we would have to add a 9 3/8" spool piece giving a possible distance of 20 3/8" from the pump discharge to the check valve.
Now my questions: Does anyone think that the silent check valve is not a good idea in my situation? Can someone give me any pros and cons by going with a silent check valve? I have my own, but I'd like to see what others have to say. Any other advice is also welcomed.
P.S.> I have to be able to get this valve no later than 3.5 weeks from now.
(Mechanical)
23 Apr 04 09:27
Crane's Technical Paper No. 410 has information on check valves. They need to be sized for the flow conditions. Check valves are a lot like control valves - they're usually one pipe size smaller than the correctly sized line in which they're installed.
Over-sized check valves never fully open, and the discs flap like flags in the wind. This is the prime cause of these valves wearing out before their time. A check that's over-sized, never fully opening, will typically have a larger pressure drop than a smaller, properly sized valve that opens right up.
(Mechanical)
26 Apr 04 18:34
Your swing check is too probably too large for the flow/pipe size.
Your line velocity is around 1.9 m/s. You want at least 2.4m/s to open the disc fully for a conventional design swing check.I assume you are pumping water If you have an external spindle, installing an arm and a spring (acting in the closed direction) will help at the expense of wasting power.
Wafer type check valves work OK and are cheap and easy to fit, but the springs eventually break and water hammer ratings are not that brilliant.
Cheers
Steve
(Mechanical)
26 Apr 04 20:22
smckennz, according to my calcs I get the following:
These are the results:
velocity ft per second: 9.
Reynold's Number: .
friction factor fa: 0.
friction factor f: 0.
head loss ft: 3.
pressure loss psi: 1.
or 2.8m/s Just curious where you got 1.9m/s
I do agree with you and tbp on the ck valve being oversized,however.
(Mechanical)
27 Apr 04 00:40
imok2,
I agree with you that line velocity is 9.2 fps (2.8 m/s). However, it is more than 2.4 m/s (from smckennz's comment). Why do you still think that check valve is oversized? Please advise me.
(Mechanical)
27 Apr 04 05:00Silent checks can quiet down the hammering, but they are often vulnerable to small particles in the pumpage, makes them stick open, many of us in the pump industry avoid them on discharge of pump because of this.Many use a split disc type check. Pretty good against hammer or to quiet the system down, much less vulnerable to sticking like silent checks. Again however, springs go away in time.
PUMPDESIGNER
(Mechanical)
27 Apr 04 19:08
Oops
you are right; 1.9m/s is your flow for a 10" line.
I would normally expect 2.8m/s to be sufficient to hold a conventional swing check open. However if you have a low Cv model the full disc lift flow may be higher. For example U/L rated swings are rated by crane to require 3.8m/s on water.
Like pumpdesigner, I dont like centerpost guided check valves lile the Apco600 unless the water/fluid is really clean.
Have a look at the Keystone Fig 86. They are a sprung wafer swing check (sort of). Cheap, with rubber seat and the spring. at 8" the full open steady flow velocity is only 1.5m/s. Normally available off the shelf. I have used heaps and wrecked only one, due to surge prevention system failure, not the fault of the valve.
When fitting be careful that there is plenty of clearance between the open disc and the makeup pipe as the disc opens into the pipe.
Cheers
Steve
(Mechanical)
27 Apr 04 20:35If you are interested in sending in a Guest Blogger Submission,welcome to write for us!
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