Check Valve

[luudee]

 

What do you guys think? This will do the job ?
 

https://www.aliexpress.com/item/Free-shippingDN50-2-SS304-1000WOG-check-valve-Stainless-steel-check-valve-BSP-thread/1536768970.html

 

Other than that I will try to contact the pump manufacturer and ask for a recommendation ...

 

rudi

 

Edited May 14, 2017 by luudee

[sipi]

No rating or a lot if info on that site Rudi.

As long as the valve face can handle being slammed against the seat with nearly 65 kilos (150 pounds) of force several times a day (according to my brief calculations) it might be ok to use as a replacement on the outlet.

I wouldn't, but others might disagree. 

What is there to lose?

Edited May 14, 2017 by sipi
tired

[Artisi]

2 hours ago, luudee said:

 

What do you guys think? This will do the job ?
 

https://www.aliexpress.com/item/Free-shippingDN50-2-SS304-1000WOG-check-valve-Stainless-steel-check-valve-BSP-thread/1536768970.html

 

Other than that I will try to contact the pump manufacturer and ask for a recommendation ...

 

rudi

 

probably the ants pants on the inlet - if on the outlet side , you are aware of my feelings so no comment :)

 

[sipi]

44 minutes ago, Artisi said:

probably the ants pants on the inlet - if on the outlet side , you are aware of my feelings so no comment :)

 

Sipi will offer a 20  year guarantee on the inlet. 

Over and out...

[luudee]

 

Sorry I wasn't clear. The consensus is that the force is smaller on the inlet

side, so I was considering the Aliexpress one for the inlet side.

 

I will try to get some recommendations from Groundfos directly this week,

and then decide what to order.

 

How about these Valves?  I'm thinking CK3R 50mm ...

http://www.tlv.com/global_pdf/tii/e-ck3m0-hp.pdf

Looks like they have a distributor in Thailand ...

 

 

Many Thanks, guys !!!

 

rudi

 

 

[Wirejerker]

With the check valve on the suction it will open when the pump kicks in and suction pressure at the pump drops below tank head pressure (20kPa).
With the check valve on the discharge it will open when the pump kicks in and discharge pressure goes above system pressure (350kPa).
And vice versa when it stops.
Draw a few pictures and think about it. 
Anyway up to Rudi.

The word is differential. Don't draw pictures. Google it. In the system it does not look at absolute but different pressure
Not sorry u started it..


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[sipi]

1 minute ago, Wirejerker said:

 

The word is differential. Don't draw pictures. Google it. In the system it does not look at absolute but different pressure
Not sorry u started it..


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Please don't be sorry. Differential pressure is different to operating pressure.

Anyway, Rudi has enough info to go on with.

[luudee]

8 hours ago, Wirejerker said:

 

A check valve on the suction will open and close at 20 kPa.

A check valve on the discharge will open and close at 350 kPa.

In a nutshell. 

 

Thanks Sipi

That's won me around to put it on the suction side

 

 

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Does this calculation include the pressure from the water storage tanks ?

2m meters tall ... will the spring be able to close it before the "hammer" comes ?

 

I'm thinking once the pump stops, the left-hand side will transition from

negative pressure (suction) to positive pressure, withing several milliseconds.

If the spring does not close the valve in time, The "hammer" effect will remain.

 

But the spring has to work against the 0.2 bar gravity-based pressure ... 

 

Did I miss something ?

 

Many Thanks,

rudi

 

[Pib]

Don't over complicate the kind of NRV needed....pretty soon we'll be talking titanium NRVs.  

 

Assuming your current NRV on the discharge side it still good, just move it to the suction side.  Or go to HomePro or most any hardware store and buy a new brass valve commonly sold for around Bt200. 

Edited May 14, 2017 by Pib

[luudee]

2 minutes ago, Pib said:

Don't over complicate the kind of NRV needed....pretty soon we'll be talking titanium NRVs.  

 

Assuming your current NRV on the discharge side it still good, just move it to the suction side.  Or go to HomePro or most any hardware store and buy a new brass valve commonly sold for around Bt200. 

 

 

If I go for a disc check valve (either side), I cannot use the 200 baht brass valves.

The pump destroys the spring within a few days   (I know if out of experience)

 

I have to do more research as to what type of disc valve would be better suited.

I'll talk to the pump manufacturer as well, see what they have to say ...

 

Thak you,

rudi

 

[Artisi]

Rudi, don't become over complicated, simply ask Grundfos for a NRV to suit your particular model pump, fit it and sleep easy. My unit has run for 6 years without a problem. If it starts having problems now, I will blame you for jinxing it. 

Edited May 14, 2017 by Artisi

[sipi]

A check valve on the suction will close with 9 pounds of pressure compared to 150 pounds on the discharge side.

You now have 2 choices. Keep upgrading the one that keeps getting smashed or put one on the suction line.

[sipi]

I will be speaking to a Grundfoss rep tomorrow and can ask him if you like. 

As I said, I am sure I have a 20 bar reconditioned stainless check valve you can have free of charge  (except postage from Australia) if you want to continue with keeping it on the outlet.

Really up to you.

Putting a good (cheap) check valve on the suction will work and improve that water hammer.

I can rant about why check valves are on the discharge side of boiler feed pumps  (to do with back flow of steam and priming), but it is irrelevant and I can't be bothered. Been doing this shit for 40 years.

Otherwise just keep upgrading the one on the discharge.

[luudee]

 

ok ok :)

 

Thanks again guys, I have sent out email and also filled out the online form on the Grundfos web site.

 

Will wait what they write. And yeah,  Iw ill move the check valve to the inlet, it's a trivial thing to do ...

 

Many Thanks to all of you !  I'll report back when I have more info about the valve, etc ...

 

rudi

[luudee]

7 minutes ago, sipi said:

I will be speaking to a Grundfoss rep tomorrow and can ask him if you like. 

As I said, I am sure I have a 20 bar reconditioned stainless check valve you can have free of charge  (except postage from Australia) if you want to continue with keeping it on the outlet.

Really up to you.

Putting a good (cheap) check valve on the suction will work and improve that water hammer.

I can rant about why check valves are on the discharge side of boiler feed pumps  (to do with back flow of steam and priming), but it is irrelevant and I can't be bothered. Been doing this shit for 40 years.

Otherwise just keep upgrading the one on the discharge.

 

 

Yeah, sure please ask the grundfos rep. It might be more difficult to get a proper answer withing Thailand.

The pump is a CH 8-50 ... and I will place the check valve on the inlet. If your rep can recommend something,

that would be great !!!

 

Many Thanks,

rudi

 

[Wirejerker]

 
Does this calculation include the pressure from the water storage tanks ?
2m meters tall ... will the spring be able to close it before the "hammer" comes ?
 
I'm thinking once the pump stops, the left-hand side will transition from
negative pressure (suction) to positive pressure, withing several milliseconds.
If the spring does not close the valve in time, The "hammer" effect will remain.
 
But the spring has to work against the 0.2 bar gravity-based pressure ... 
 
Did I miss something ?
 
Many Thanks,
rudi
 

Yes you did miss something. The hammer is the result of reverse flow. Nothing to do with pressure. It's more about Dynamics Simply F=Ma with is a lot more than the system pressure or the 2 meter head. Stop the reverse flow earlier and problem fixed. Swing valves are fantastic in pipe work but if u want a cycling pressure system they are shit


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[luudee]

23 minutes ago, Wirejerker said:

Yes you did miss something. The hammer is the result of reverse flow. Nothing to do with pressure. It's more about Dynamics Simply F=Ma with is a lot more than the system pressure or the 2 meter head. Stop the reverse flow earlier and problem fixed. Swing valves are fantastic in pipe work but if u want a cycling pressure system they are shit


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Thank you for the explanation ! Much appreciated.  :) 

 

rudi

[Wirejerker]

ive gotta get a life


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[Crossy]

10 minutes ago, Wirejerker said:

ive gotta get a life

 

It is unfair and against forum rules to cause members to drool into their keyboards!

 

And before anyone asks where to find Headmasters, WJ isn't in Thailand

 

[Wirejerker]

 
It is unfair and against forum rules to cause members to drool into their keyboards!
 
And before anyone asks where to find Headmasters, WJ isn't in Thailand
 

U missed the point. I'm a slow typist and half a beer behind and that sort of thing gets me down


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[Pib]

2 hours ago, luudee said:

 

If I go for a disc check valve (either side), I cannot use the 200 baht brass valves.

The pump destroys the spring within a few days   (I know if out of experience)

 

I have to do more research as to what type of disc valve would be better suited.

I'll talk to the pump manufacturer as well, see what they have to say ...

 

Thak you,

rudi

 

It destroyed the NRV on the "discharge" side which you are going to remove, right?.

 

You haven't tried a NRV no the suction side yet.   I would think the forces on the suction side will be far lower than on the discharge side. 

 

One thing you said in an earlier in post #6 which was:"

Quote

 

The line pressure is about 3.5 bar. When the pump stops and the valve closes, it generates

a very loud bang. There is a lot of force behind it ...

 

You may have a water hammer problem which you can google-up on which is causing destruction of the check valve on the discharge side and the loud bang...a water hammer problem that may exist even without a NRV anywhere in the system (suction or discharge side).  Here's a starter google link on water hammer and you will notice it uses the phrase "loud bang."

http://www.plumbingmart.com/water-hammer-information.html

 

I would just remove the NRV on the discharge size and put a NRV on the suction side (just get a plain jane brass NRV at Homepro or similar hardware store). 

Edited May 14, 2017 by Pib

[Artisi]

23 minutes ago, Pib said:

It destroyed the NRV on the "discharge" side which you are going to remove, right?.

 

You haven't tried a NRV no the suction side yet.   I would think the forces on the suction side will be far lower than on the discharge side. 

 

One thing you said in an earlier in post #6 which was:"

You may have a water hammer problem which you can google-up on which is causing destruction of the check valve on the discharge side and the loud bang...a water hammer problem that may exist even without a NRV anywhere in the system (suction or discharge side).  Here's a starter google link on water hammer and you will notice it uses the phrase "loud bang."

http://www.plumbingmart.com/water-hammer-information.html

 

I would just remove the NRV on the discharge size and put a NRV on the suction side (just get a plain jane brass NRV at Homepro or similar hardware store). 

 

A repeat of good advice suggested many times that Rudi has indicated he will implement. 

 

[Artisi]

Having had a quick  search of the internet and unable to locate anything on the correct / best use of NRV's in a typical pump, pressure tank, pressure switch arrangement, I am considering writing up a discussion for review - assuming I can get my arse into gear and search out more data as there are a few complex changing conditions as the system is being pressurised. Anyone want to contribute ideas / comments -  please do.. 

[sipi]

7 hours ago, Artisi said:

Having had a quick  search of the internet and unable to locate anything on the correct / best use of NRV's in a typical pump, pressure tank, pressure switch arrangement, I am considering writing up a discussion for review - assuming I can get my arse into gear and search out more data as there are a few complex changing conditions as the system is being pressurised. Anyone want to contribute ideas / comments -  please do.. 

Make a simple system with a pressure guage on the suction and discharge lines so "students" can physically see what happens when the pump cycles.

Edited May 14, 2017 by sipi

[canuckamuck]

IMO the NRV on the suction side will be better protected from the water hammer because the pump will act as a baffle. 

[sipi]

I had a chat with the Grundfoss man.

A check valve on the discharge side without a pressure tank/ accumulator must be a spring/ disc type of the correct rating (Spirax sarco etc). ie photo 1.

A check valve on the suction side when an accumulator is fitted  (on the discharge side obviously) is normally the stainless flap type (appflo, arita or whatever you can find locally). ie photos 2 and 3.

I am on my phone so can't edit the photos but both check valves can be seen.

 

[luudee]

On 5/15/2017 at 6:20 AM, sipi said:

I had a chat with the Grundfoss man.

A check valve on the discharge side without a pressure tank/ accumulator must be a spring/ disc type of the correct rating (Spirax sarco etc). ie photo 1.

A check valve on the suction side when an accumulator is fitted  (on the discharge side obviously) is normally the stainless flap type (appflo, arita or whatever you can find locally). ie photos 2 and 3.

I am on my phone so can't edit the photos but both check valves can be seen.

 

4

 

Many thanks, sipi ! Much appreciated !!!

 

rudi

 

 

 

[sipi]

Can you let us know the final outcome please Rudi?

Unfortunately with most diy threads, members volunteer helpful info (hopefully) only to have the thread ride off into the sunset.

Occasionally it would be great to get some feedback, good or bad.

[Pib]

But Rudi may have got so much info and recommendations (some conflicting) that he may feel like below.

 

[luudee]

On 5/16/2017 at 6:37 PM, sipi said:

Can you let us know the final outcome please Rudi?

Unfortunately with most diy threads, members volunteer helpful info (hopefully) only to have the thread ride off into the sunset.

Occasionally it would be great to get some feedback, good or bad.

 

 

Yes, I will post an update when I fix it !  I promise! 

 

I have now ordered a stainless steel swing check valve, and will implement the changes when it gets here !

 

Thanks,

rudi