tilting disc check valves are a lot smaller and lighter so for a given pipe size they don't cost as much. Since the tilting disc is partially balanced, the cracking pressure is less-Particularly for vertical upward flow. Neither will work well for vertical downward flow, and neither will be happy if they are not installed right-side up.

RE: Tilting Disc Check vs Swing Check Valve

stanier

(Mechanical)

12 Aug 07 19:01

What you aim for is a valve with a low mass and short travel so that is is closed before the returning pressure wave will slam it shut. The tilt check by its geometry is better than a swing check valve. the latter has been described as "agricultural at best".

Refer Fluid Transients in Pipeline Systems ARD Thorley. Also check out the Delft Laboratory site. Delft have tested check valves for dynamic performance. Als see

The characteristics of the tilt check valve are such that the potential for waterhammer are reduced. Not as much as you would see with an annulus type non slam check valve.What you aim for is a valve with a low mass and short travel so that is is closed before the returning pressure wave will slam it shut. The tilt check by its geometry is better than a swing check valve. the latter has been described as "agricultural at best".Refer Fluid Transients in Pipeline Systems ARD Thorley. Also check out the Delft Laboratory site. Delft have tested check valves for dynamic performance. Als see www.pipingdesign.com where there are papers on surge.

Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au

RE: Tilting Disc Check vs Swing Check Valve

caihui

(Mechanical)

13 Aug 07 04:49

I think the tilting disc check valve's life is longer then the common swing check valve. As the damage from disc is smaller then the common swing check valve.

RE: Tilting Disc Check vs Swing Check Valve

JimCasey

(Mechanical)

13 Aug 07 08:57

Seconding what stanier said, as I recall the tilting disc is airfoiled so it goes to fully open position and stays there. A swing disc valve continually bounces around and ultimately the pin wears which mat make it hang open, leak due to misalignemnt, or the pin may even fail. If the disc goes downstream it inevitably finds something expensive to jam.

You will get efficient and thoughtful service from LEFLOW.

RE: Tilting Disc Check vs Swing Check Valve

terje61

(Mechanical)

13 Aug 07 10:58

I support the replies from both JimCasey and Stanier and the descibtion that swing checks are "agricultural at best".

During the NEL valve workshop in Aberdeen (October 2005) there was an interesting paper about Maintenance, Inspection and Testing of Non-Return Valves. This paper was presented following a near accident on a British platform where 12 out of 12 swing check valves in a production line failed.

However, Priya, correct valve selection should always be based on the application. For standard non-return applications a tilting disc or dual plate check valve will do. For more critical applications (e.g. to protect expensive rotating equipment or potential risk of waterhammer) an axial or non-slam check valve type is recommended.

RE: Tilting Disc Check vs Swing Check Valve

grandnobi

(Mechanical)

17 Aug 07 14:02

What I hate most about tilting disc check valves is the restricted accessibility for maintentance.

The body of a swing check valve typically is equipped with a separate flanged cover plate. This allows you to access the flapper for maintenance or to remove the flapper for line testing and flushing while the valve remains in installed condition.

Tilting disc valves, however, typically have a split body. You have to remove the entire valve body for maintenance. It is even worse where tilting disc checks valves are equipped with butt welding ends. In this case the pipping manifold has to be spread apart for maintenance. Sometimes this requires the provision of additional break flanges.

RE: Tilting Disc Check vs Swing Check Valve

stanier

(Mechanical)

18 Aug 07 00:16

Of course if you used an annulus type non slam valve such as Noreva or Mokveld you wouldnt need to be continually taking your check valves apart for maintenance.

The prime cost of a piece of mechanical equipment may only be 12% of its whole of life cost if it is a high maintenence item. Great if you want job security in maintenance but if you are the owner and want reduced life cycle costs and plant availability avoid the swing check and the dual plate type valves.

There are two types of damage by surge. The first is obvious and something breaks. The second is the damage from repetitive events that cause fatigue failure of seals, glands, discs, seats, shafts and gaskets. When one piece of equipment finally succombs to this type of failure you are then reliant on the standby which is in a parlous state itself having been subjected to the same fatigue history.

Design the system for whole of life not the maintenance crew's career path and longevity!

Grandnobi,Of course if you used an annulus type non slam valve such as Noreva or Mokveld you wouldnt need to be continually taking your check valves apart for maintenance.The prime cost of a piece of mechanical equipment may only be 12% of its whole of life cost if it is a high maintenence item. Great if you want job security in maintenance but if you are the owner and want reduced life cycle costs and plant availability avoid the swing check and the dual plate type valves.There are two types of damage by surge. The first is obvious and something breaks. The second is the damage from repetitive events that cause fatigue failure of seals, glands, discs, seats, shafts and gaskets. When one piece of equipment finally succombs to this type of failure you are then reliant on the standby which is in a parlous state itself having been subjected to the same fatigue history.Design the system for whole of life not the maintenance crew's career path and longevity!

Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au

RE: Tilting Disc Check vs Swing Check Valve

CWFCNuclear

(Nuclear)

15 Nov 07 17:49

If your velocity is not high enough to hold the disc fully open both the swing check and tilting disc valve will experinece bushing/hinge pin wear. Once difference between tilting disc and swing check is that the TD is very intolerant to any wear and will result in seat leakage. Swing checks with moderate hinge/bushing wear may still seat tightly at high DP.

If your velocity is below 10-12 fps water, expect disc oscillation for a swing or TD valve. These are ballpark numbers and differ based on the specific desings.

RE: Tilting Disc Check vs Swing Check Valve

stanier

(Mechanical)

15 Nov 07 18:59

Great insight of what industry already knows. Given the nuclear industry's routine documentation of failures is there a Report you can reference?

CWFCNuclear,Great insight of what industry already knows. Given the nuclear industry's routine documentation of failures is there a Report you can reference?

Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au

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News

Pros and Cons of 2 Check Valves Types

One of the most essential valves in water and wastewater pumping systems is the check valve. Its purpose is to automatically open while pumps are running, and return to the closed position to prevent reverse flow when the pumps are not in operation. These valves help minimize energy consumption and protect the pumping system from pressure surges and damage from reverse flow.

Selecting check valves for a process is like selecting hardware for new cabinets. Once you decide on a knob or a handle, there's a multitude of styles, colors, and price points to consider beyond that. Same with check valves. It's pretty clear the process you're working on requires a check valve, but which one? Each style of check valve is designed to meet a certain need. Here's the pros and cons of two different styles of check valves, the lift check and swing check.

Lift Check Valves

Lift check valves are commonly used in high-rise buildings, industrial and power plant applications, and water and wastewater applications. They have no external moving parts and are known to be economical and reliable. Over time, these types of valves can have high energy costs because the disc remains in the flow stream during operation.

Silent Check Valve

Silent check valves are known for their quiet closure. Flow pushes the disc to allow forward flow. When the pump is stopped, a compression spring pushes the disc into the seat before flow reverses, hence the silent closure.

This type of check valve is most commonly used in clean water applications with high head.

Nozzle check valves are very similar to the silent check valve, are meant for high pressure, industrial and power applications.

Ball Check Valve

Ball check valves are commonly used in water and wastewater applications. They have very simple operation, and are compact and economical too. These valves feature a rubber coated ball that moves in and out of the seat as flow moves forward and reverse.

Because the ball has a long way to travel when the pump shuts off, these valves have a high tendency to slam in high head applications.

Swing Check Valves

Swing checks are certainly some of the most common check valves used in water and wastewater pumping systems. They're readily available and relatively low cost. They're also automatic, requiring no external power source, guided only by the direction of flow.

These valves can come in a few different configurations, operating in the same basic way.

Dual-Disc

This check valve features a wafer body design and two D-shaped discs that rotate out of the way as flow enters the valve. It has good non-slam characteristics, but is not recommended for wastewater applications. It is also susceptible to vibration and wear.

Traditional Swing Check

Everyone knows this one, right? It's definitely the most common check valve in water and wastewater applications. This type of valve usually has metal or resilient seats and a 60-90 degree swing. This valve has a tendency to slam, however, due to the long stroke, friction in the packing, and inertia of the disc.

Air cushions are sometimes employed to help alleviate the slamming. Though some believe that a lever and spring is a better accessory as they allow the valve to close faster.

Tilted Disc Check Valve

The difference between the tilted disc check valve and the traditional swing check valve is that flow is allowed to pass on both sides of the disc. Because of this, it allows for extremely low head loss.

This valve is not recommended for wastewater applications because pins that extend into flow stream tend to collect debris. Clean water or treated effluent are best for this valve.

Do you have the right type of check valve for your application? Could there be a better one? Always discuss changes to your pumping system with an engineer who is well versed in all types of check valves. They may be able to help you find a valve that slams less or could even be more energy efficient.

Not sure if you should change up your check valves? Ask us about it! We gladly provide technical assistance to businesses and municipalities in Wisconsin, Minnesota, Illinois, and upper Michigan.

If you want to learn more, please visit our website tilting disc check valves factory.

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