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Check valve Position

8

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Check valve Position

Check valve Position

alienitmeca

(Mechanical)

(OP)

15 Jun 16 09:45

Hello,

When designing your piping layout, one would certainly have to use a fair amount of valves of various types (check valves, gate valves, butterfly valves...) to choose one type over the other demand some thinkig along with good engineering skills and operating conditions, My question is included in this department:

when on uses a check valve along with a gate valve (at the outlet of a pump, inlet of storage tank...) how to know when to put check valve then put gate after in it or is it the other way around ? Could you help me how to decide in this matter.

Thnk you

RE: Check valve Position

LittleInch

(Petroleum)

15 Jun 16 10:17

The reasoning is that the check valve is difficult to drain past and if you shut the isolation valve you can lock in fluid between the two. Hence if you drain the pump, not all the fluid leaks or can suddenly escape.

Do it the other way around and the fluid is able to flow from the isolation valve to NRV side to somewhere downstream.

Inlet to a tank would be the same thing in direction of flow - isolation then NRV then tank.

My way of thinking is that in the direction of flow you have the isolation valve and then the check valve.The reasoning is that the check valve is difficult to drain past and if you shut the isolation valve you can lock in fluid between the two. Hence if you drain the pump, not all the fluid leaks or can suddenly escape.Do it the other way around and the fluid is able to flow from the isolation valve to NRV side to somewhere downstream.Inlet to a tank would be the same thing in direction of flow - isolation then NRV then tank.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

4

pennpiper

(Mechanical)

15 Jun 16 12:31
Check valves tend to fail more often the isolation valve. So if you have to remove the NRV at a tank you will risk draining all of the fluid in the Tank if you place the isolation valve as Little said.

Rule to remember is the isolation valve should always protect the greater inventory of product

For check valves at Pump Discharge it should be: Pump, then Check Valve, then Isolation valveCheck valves tend to fail more often the isolation valve. So if you have to remove the NRV at a tank you will risk draining all of the fluid in the Tank if you place the isolation valve as Little said.Rule to remember is the isolation valve should always protect the greater inventory of product

Sometimes its possible to do all the right things and still get bad results

RE: Check valve Position

bimr

(Civil/Environmental)

15 Jun 16 13:43

http://www.flowcontrolnetwork.com/pump-guy-mailbag...

Both a check and gate valve should be installed in the discharge piping with the check valve placed between the pump and the stop valve to protect the pump from reverse flow and excessive back pressure.

RE: Check valve Position

LittleInch

(Petroleum)

15 Jun 16 15:18

So in two posts you have two different ways of doing it - never simple eh.

The tank I'll give you, but in reality how many times is an NRV ever removed from pump??So in two posts you have two different ways of doing it - never simple eh.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

europipe

(Chemical)

16 Jun 16 06:10

I think you're alone now, little.
I always saw it like mr. Pennock sais.
Also, for discharge at a pump, in many cases a pressure relief drain is placed between check- and isolation valve.

RE: Check valve Position

LittleInch

(Petroleum)

16 Jun 16 09:08

That's my point - if you don't put your pressure relief and drain between the two you can run into problems. Put it the other side and you don't need to bother if the single PRV and drain connection is on the other side.

From a purely process view, either location is fine - a lot depends on particular piping layouts and orientations.

I've seen both and ultimately this is a view the designer needs to take, but there are no "rules" to this, only custom and practice.

"in many cases a pressure relief drain is placed between check- and isolation valve"That's my point - if you don't put your pressure relief and drain between the two you can run into problems. Put it the other side and you don't need to bother if the single PRV and drain connection is on the other side.From a purely process view, either location is fine - a lot depends on particular piping layouts and orientations.I've seen both and ultimately this is a view the designer needs to take, but there are no "rules" to this, only custom and practice.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

donf

(Chemical)

16 Jun 16 15:22

I agree with Pennpiper (pump-check valve-isolation valve). In a parallel pump arrangement, having an isolation valve between the check valve and THE OTHER pump allows the defective check to be replaced, while the OTHER pump is pumping.

donf

RE: Check valve Position

LittleInch

(Petroleum)

16 Jun 16 15:36

You guys have a lot of defective check valves.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

europipe

(Chemical)

16 Jun 16 17:54

Check valves are never 100 percent reliable.

RE: Check valve Position

alienitmeca

(Mechanical)

(OP)

20 Jun 16 10:55

Thank you everyone for your responses,

it's been quite an interesting discussion, very informative as well

RE: Check valve Position

BigInch

(Petroleum)

20 Jun 16 17:10

LittleInch, you give up too easily.

The preferred arrangement should not be decided based on facilitating check valve, or any other valve's maintenance. It is far more important to facilitate pump maintenance, as the pump will statistically be the most frequent item requiring break out maintenance of one sort or another. Pump, isolation valve and check is thus the preferred solution, as no pressure will be trapped between isolation and check valves nor will any pressure be in the maintenance's crews face when breaking out the pump. If you do it the wrong way, then you must add the extra vent valve to release the resulting trapped pressure.

If there is any concern about draining adjacent piping or tanks, provide an appropriate spectacle blind.

RE: Check valve Position

LittleInch

(Petroleum)

20 Jun 16 21:51

Fully agree, makes sense to me.

BI welcome back, haven't seen you on here for a while....Fully agree, makes sense to me.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

BigInch

(Petroleum)

21 Jun 16 09:43 Thanks.
I've had some other priorities to attend to lately.

Thanks.I've had some other priorities to attend to lately.

RE: Check valve Position

Krausen

(Mechanical)

24 Jun 16 14:52

It really does depend on the system layout. The pump + block valve + check (or meter + block valve + check) sequence is the best choice IMO for reasons LI explained, but should only be used in systems where the piping/equipment can be blocked in elsewhere without suffering a major downtime. In my work we apply this layout about 80%-90% of the time. We've had clients who are adamant on flipping the block & check, without appealing to reason other than "we've always done it that way".

If you are flowing into a system that is not easily isolatable (e.g. injection into a mainline that runs 24/7), the pump + check + block valve is the better option due to having to shut down an entire mainline in order to service a defective check valve.

RE: Check valve Position

BigInch

(Petroleum)

25 Jun 16 09:11

Then you have the same problem when your block valve needs to be repaired.

RE: Check valve Position

georgeverghese

(Chemical)

27 Jun 16 03:51

In many cases, a check valve has a process safety function, and this may in some cases where the consequence of a check valve failure poses some safety and loss of production risks, demand some means of isolation on BOTH sides of the check valve to run a leak integrity test and have it removed for repair where necessary. Else you have a large volume of gas or liquid to dispose off before this test and removal can be done.

The periodic scheduled verification of a check valve's integrity in such services has increased in importance in the last 10-15years or so. On the other hand, manual isolation valves are not process safeguarding devices.

RE: Check valve Position

flukeynub

(Mechanical)

18 Jul 16 16:08

This is the exact question I've been asking some of my firm's senior engineers to shed some light on in the last two weeks without much luck.

I debated this question with myself at my last job (was an operations engineer) and decided at the time I preferred pump/check/iso mainly because we saw many more problems with check valve failures than pumps/iso valves. I had to redesign an acid scrubber spray system to allow for check valve replacement as process system up time was significantly more important than ease of pump maintenance. Not to mention, for some reason, none of the pump/check/iso configurations at that site had a vent which is why I even thought about this in the first place.

Thanks for the opposite thought process perspective!

RE: Check valve Position

lilliput1

(Mechanical)

18 Jul 16 17:12

Pump, check valve then isolation valve so check valve can be serviced without draining the line. The isolation valve is normally left open all the time. It is closed only when pump or check valve servicing is required. The check valve insures no back flow when pump is stopped and there is a parallel pump operating. Typically for chilled water service, the chiller automatically starts its associated pump and the pump isolation valve is open.

RE: Check valve Position

bimr

(Civil/Environmental)

18 Jul 16 21:44

Check valves are not considered to be reliable so process safety engineers do not use check valves for process safety functions.

RE: Check valve Position

2

JJPellin

(Mechanical)

19 Jul 16 13:02

API Recommended Practice 686; Second Edition

&#;A check valve shall be installed in the discharge line of all pumps, compressors or blowers, whether centrifugal or rotary, unless there is no possibility of a reverse flow or pressure surge (such as water hammer) under any conditions. The check valve shall be located between the machine discharge flange and the discharge block valve.&#;

Hydraulic Institute Standards for Centrifugal, Rotary & Reciprocating Pumps, fourteenth edition

&#;A check valve and a stop valve should be installed in the discharge line. The check valve, placed between the pump and the stop valve, is to protect the pump from reverse flow and excessive back pressure.&#;

Piping Design for Process Plants; Rase and Holmes;

&#;Place check valve between discharge nozzle and gate valve to prevent liquid backup when pump stops running.&#;

I have worked with many thousands of centrifugal pumps over the past 27 years. I don&#;t recall ever seeing the check valve installed outside of the first block valve.

I work in a large US oil refinery. We have about centrifugal pumps. All of them, except for two have the check valve between the pump discharge flange and the block valve. This is a requirement of our standards. Perhaps some references could help.API Recommended Practice 686; Second Edition&#;A check valve shall be installed in the discharge line of all pumps, compressors or blowers, whether centrifugal or rotary, unless there is no possibility of a reverse flow or pressure surge (such as water hammer) under any conditions. The check valve shall be located between the machine discharge flange and the discharge block valve.&#;Hydraulic Institute Standards for Centrifugal, Rotary & Reciprocating Pumps, fourteenth edition&#;A check valve and a stop valve should be installed in the discharge line. The check valve, placed between the pump and the stop valve, is to protect the pump from reverse flow and excessive back pressure.&#;Piping Design for Process Plants; Rase and Holmes; &#;Place check valve between discharge nozzle and gate valve to prevent liquid backup when pump stops running.&#;I have worked with many thousands of centrifugal pumps over the past 27 years. I don&#;t recall ever seeing the check valve installed outside of the first block valve.

Johnny Pellin

RE: Check valve Position

JJPellin

(Mechanical)

19 Jul 16 13:41

Centrifugal Pumps; Karassik and Carter,

&#;Generally, both a check valve and a gate valve are installed in the discharge line. The check valve is placed between the pump and the gate valve and protects the pump against reverse flow in the event of unexpected driver failure.&#;

Pump User&#;s Handbook; Bloch and Budris,

&#;Gate valve should not be between check valve and pump.&#;

Does anyone have a published reference or standard that shows the check valve outside of the block valve?

I pulled another couple of books off my shelf.Centrifugal Pumps; Karassik and Carter, &#;Generally, both a check valve and a gate valve are installed in the discharge line. The check valve is placed between the pump and the gate valve and protects the pump against reverse flow in the event of unexpected driver failure.&#;Pump User&#;s Handbook; Bloch and Budris, &#;Gate valve should not be between check valve and pump.&#;Does anyone have a published reference or standard that shows the check valve outside of the block valve?

Johnny Pellin

RE: Check valve Position

bimr

(Civil/Environmental)

19 Jul 16 14:58

Agree with JJPellin. Have never witnessed any other installation.

If there is a requirement to eliminated the pressure trapped between isolation and a check valve, a small drain line w/valve is included.

RE: Check valve Position

lilliput1

(Mechanical)

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4 Pieces of Advice to Choose an Industrial Valve for Oil and Gas Industries 19 Jul 16 15:22

Pressure between check valve and closed block valve would only be a concern is the trapped fluid is colder than ambient and it expands as it heats up.

RE: Check valve Position

BigInch

(Petroleum)

19 Jul 16 16:07

The hydraulic facts are that a check valve installed downstream of the pump and block valve is equally adept at stopping backflow to the pump as a check valve upstream of the block valve ... unless the block valve is already closed, but that would mean no backflow is possible at all
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All those references ... and there is no accompanying logic to justify the requirements???The hydraulic facts are that a check valve installed downstream of the pump and block valve is equally adept at stopping backflow to the pump as a check valve upstream of the block valve ... unless the block valve is already closed, but that would mean no backflow is possible at all

RE: Check valve Position

europipe

(Chemical)

19 Jul 16 16:18

BI, I think like most of us a checkvalve is no reliable option to close a system, a blockvalve is.
So exchange a checkvalve is easier to do, like mr. Pellin sais.

RE: Check valve Position

JJPellin

(Mechanical)

19 Jul 16 16:18

We fail check valves quite often. Some of our check valves are designated as critical checks for mitigation of process risk associated with back-flow. Those valves often have to be pulled and inspected on some defined frequency.

Most of the time, the process downstream of the block valve can only be taken out of service at a major turnaround (every 4 to 6 years). I have never heard of any problem with stored pressure between the check valve and the block valve. If the check valve is outside of the block valve and it fails, I have to shut down a process unit (potentially costing millions of $US). If the check valve is inside of the block valve, I might have to use a short spool with a bleed valve to eliminate the possibility of stored pressure trapped between the valves. This is not a problem for me. Putting the check outside of the block valve seems to have a huge potential downside (unit shutdown) with no real upside. The fact that every standard I can find goes to the trouble to specify this arrangement suggests that a lot of people have reached that same conclusion.

Johnny Pellin

RE: Check valve Position

bimr

(Civil/Environmental)

20 Jul 16 00:05 Pressure between check valve and closed block valve would only be a concern is the trapped fluid is colder than ambient and it expands as it heats up.

How do you relieve pressure when you line break the pipeline for maintenance?

Link

Regarding:How do you relieve pressure when you line break the pipeline for maintenance?

RE: Check valve Position

lilliput1

(Mechanical)

20 Jul 16 01:00

One could slowly unbolt the flanges so the fluid leaks out to relive the pressure. Or maybe the pump needs to be serviced because fluid has already leaked out and relived the pressure!

RE: Check valve Position

bimr

(Civil/Environmental)

20 Jul 16 01:25

https://www.google.com/?gws_rd=ssl#q=Line+Breaking...

Last time I checked, it is and employees working for responsible corporations have line breaking/opening procedures for safety of the employees working on piping.

RE: Check valve Position

lilliput1

(Mechanical)

20 Jul 16 01:51

bimr,
You are right. Steam pipes and hot water pipes need to be able to relieve pressure so as not to cause injury when disconnecting piping or equipment. Provide drain valves and blow off valves at strainer. Locate between equipment and block valve.

RE: Check valve Position

LittleInch

(Petroleum)

20 Jul 16 07:57

Having said that sometimes they do work very well and the key point is to look at your particular system and piping layout and make sure you can vent and drain between a check valve and its downstream block valve. If your particular use of check valves is such that they are seen as critical to the process, used in anger a lot and hence more likely to fail, then suitable isolation needs to be in place and for many this will be between the pump and the pump isolation valve. For others it might not or the check valve is there for an extreme event and not used in anger very often so would be expected to last for a long time and can be upstream or downstream.

So the key answer (for me) to the original question is look at your systems and understand the issues over space, potential for removal or servicing, isolation requirements and impact on the process and the ability to drain sections of piping when you install check valves.

I can certainly see the point here and maybe what it highlights is the difference between process plant type pumps and pipeline type units. Use of check valves for a process function is different to using it for a pressure break / safety function. You can take credit for a check valve to reduce back flow, but not to seal.Having said that sometimes they do work very well and the key point is to look at your particular system and piping layout and make sure you can vent and drain between a check valve and its downstream block valve. If your particular use of check valves is such that they are seen as critical to the process, used in anger a lot and hence more likely to fail, then suitable isolation needs to be in place and for many this will be between the pump and the pump isolation valve. For others it might not or the check valve is there for an extreme event and not used in anger very often so would be expected to last for a long time and can be upstream or downstream.So the key answer (for me) to the original question is look at your systems and understand the issues over space, potential for removal or servicing, isolation requirements and impact on the process and the ability to drain sections of piping when you install check valves.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

georgeverghese

(Chemical)

21 Jul 16 05:43

Whilst on this topic of check valves, though not the topic of discussion, some OpCos have stopped the use of wafer style check valves for at least 10years now when in flammables service.

RE: Check valve Position

europipe

(Chemical)

21 Jul 16 07:12

George, can You explain why, and why 10 years?

RE: Check valve Position

MickMc

(Mechanical)

21 Jul 16 08:13

It is common for wafer style valves not to permitted in hydrocarbon service as in fire case the stud bolts are unprotected and liable to fail first.

RE: Check valve Position

europipe

(Chemical)

21 Jul 16 08:38

Ah, the fire situation, what is OpCos?

RE: Check valve Position

BigInch

(Petroleum)

21 Jul 16 16:29

Perhaps it means operating companies.

RE: Check valve Position

europipe

(Chemical)

21 Jul 16 16:47

That's a wide understanding

RE: Check valve Position

georgeverghese

(Chemical)

22 Jul 16 04:12

Yes, long bolts on wafer style checks tend to loosen more during a fire...

At least in Shell, wafer style checks were removed from their piping classes since the year or so.

OpCos = Operating Companies.

RE: Check valve Position

LittleInch

(Petroleum)

22 Jul 16 06:37

See this - slide 10 is the key one comparing a "normal" flange and a long bolt one.

This is a one page version of the same thing

I've seen pictures and videos of long bolt wafer checks and wafer valves during a fire compared to other bolts and it's alarming. Unless there is no possibility of a pool fire underneath it or you fire protect it, this would / should come up in a HAZOP or similar safety review of the plant design or just be banned for new installations.See this - slide 10 is the key one comparing a "normal" flange and a long bolt one. http://slideplayer.com/slide// This is a one page version of the same thing https://www.google.co.uk/url?sa=i&rct=j&q=...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Check valve Position

europipe

(Chemical)

22 Jul 16 07:48

What about spect. blinds then?
They have also longer bolt lenghts.

RE: Check valve Position

LittleInch

(Petroleum)

22 Jul 16 08:28

Mostly they refer to flangeless valves, but clearly the longer the bolt the worse it gets in terms of expansion in the event of fire.

My guess would be if you more than double the length of the bolt then you start to run into that issue, but haven't done any calcs on that.

Not as long as those being noted in the reports.Mostly they refer to flangeless valves, but clearly the longer the bolt the worse it gets in terms of expansion in the event of fire.My guess would be if you more than double the length of the bolt then you start to run into that issue, but haven't done any calcs on that.

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News

Check valves are critical in backflow prevention. They protect pumps and compressors in a process system and prevent wet wells from flooding. Proper check valve selection and installation will prevent premature wear of the valve and an unscheduled shutdown. The keys to successful check valve performance are valve selection, size, pipeline installation and cost of ownership. Time spent evaluating these key considerations will maximize check valve operational performance.

Evaluation Before Valve Selection

The design of the pumping system should be evaluated before selecting a check valve. First, consider whether the pump system design has potential surge issues. If surge issues are a concern, then a surge investigation should be performed by a valve manufacturer. The surge investigation may determine whether a pump control valve is better suited for the application than a check valve.

Key Check Valve Considerations

 

Valve Style: Selecting the appropriate style check valve starts with understanding the process media. The type of media &#; whether it is clean, abrasive, corrosive or slurry &#;  determines what style of check valve should be selected. For clean service, check valve styles such as slanting disc, double door and silent are most common for low head loss, large pipe or quick closure requirements. Although rubber flapper and swing check valves can be used in clean service, they are typically used in wastewater service. These valves are more suitable for abrasive/corrosive/dirty applications and rapid flow reversal. Swing check valves are commonly used for pump discharge applications due to control options that accommodate varying forward and reverse flow conditions.

60-inch swing check valve for critical backflow prevention. All images courtesy of DeZURIK, Inc.

Valve Size: Correct valve size is important to valve performance and may or may not be the same as the pipeline size. For best valve performance, sizing calculations for minimum, normal and maximum flow conditions are necessary to optimize valve life and minimize valve maintenance. The American Water Works Association standard (AWWA C508) for swing check valves states: &#;Valves may be subjected to excessive wear if there is insufficient flow to open the valve.&#;

Rubber flapper valves are typically sized to be fully closed or fully open with sufficient flow. Conversely, full waterway swing check valves are not typically sized for full open but are sized for the lowest acceptable head loss per the design. If the valve is sized too large and normally operates nearly closed, the disc connection can be worn. Premature wear can occur on the disc connection through vibration, oscillation and force until the metal connection is ground away and no longer allows the disc to seat properly in the valve body.

Case Study 1 

In one installation, a swing check valve was oversized because they were planning for future growth. The low flow rate of the valve resulted in the valve only being open 17 degrees. The near-vertical disc was subjected to high-velocity water flow near the top of the disc and low-velocity swirling water at the bottom of the disc. The unbalanced dynamic forces on the disc caused the disc to wobble and wear the connecting parts. The pin and connections were worn down and the center hole in the disc was worn out, not allowing the disc to close properly. In time, the disc became loose and failed to close.

Valve Installation: Valve installation in the pipeline is a critical consideration to the success of the check valve. The recommendation by Manufacturers Standardization Society of the Valve and Fittings Industry (MSS SP- 92) is to install a check valve at a minimum of 10 pipe diameters of straight pipe on the downstream side from tees, fittings, increasers or pumps and five pipe diameters from elbows to ensure laminar flow with minimum turbulence to minimize disc movement and premature wear. However, many facilities with smaller footprints have achieved acceptable performance in systems with the check valve installed five pipe diameter lengths of straight pipe from the downstream side of tees, fittings, increasers or pumps and three pipe diameters lengths from elbows, as shown in the illustration below. Consult the valve manufacturer for design pipe distances less than the recommendation by MSS.

Although MSS SP-92 recommends 10 pipe diameter lengths for check valve installation downstream from pumps, many facilities achieve acceptable performance with five pipe diameter lengths from pumps, after checking with the valve manufacturer.

Design Goal: The goal of design planning is to minimize the facility footprint without compromising equipment performance. Equipment will last longer under laminar flow and with no sudden changes in flow velocity. Sudden changes in flow velocity occur during a sudden pump shutdown when the flow reverses and is stopped by the closing of the check valve. This sudden stop in fluid flow or flow velocity change instantly reduces the pressure below the vapor pressure and may cause momentary column separation. The vacuum created by the column separation draws the two columns together violently. When the columns rejoin it creates a high-pressure shockwave, also known as water hammer. Water hammer creates a loud banging sound which is disruptive and the accompanying pressure surge could be destructive if left untreated.

AWWA C508 states: &#;Conditions of water hammer, hydraulic pulsation, and excessive operating noise are results of system design rather than valve design and are beyond the scope of this standard and require special design and construction considerations.&#;

Flow Characteristics: Shown below are Computational Fluid Dynamics (CFD) analysis of a check valve near an increaser. Eddies formed at the bottom of the increaser and created turbulent flow through the check valve. Moving the check valve away from the increaser removed the eddies and created a more laminar flow through the check valve, as shown in the second CFD image.

Unbalanced dynamic forces on the check valve disc caused the disc to wobble and wear.

Moving the check valve further from the increaser decreased turbulence and allowed flow to become more laminar.

Increaser: Another way to ensure more laminar flow is to limit the size of the increaser between the pump and check valve so it is not greater than two pipe sizes. For example, if the pump discharge is 12 in. it would be acceptable to use an increaser to a 14- or 16-in. check valve size, but any larger would be too extreme.

Case Study 2:

In another installation, because of the facility&#;s extremely compact footprint, the check valve was installed immediately after the pump and increaser with little pipe length distance between the check valve and pump. The high-velocity pump discharge focused a jet of water directly at the check valve disc and pin connections, prematurely wearing out the valve components and causing improper seating of the disc.

Cost of Ownership: When selecting the proper check valve, it is important to consider the cost of ownership. The cost of ownership includes initial cost, operating cost and maintenance cost. An inexpensive check valve may end up costing less at startup but may cost more in the long run with unscheduled maintenance and downtime than a valve that is better suited for the application. The more suitable valve will perform better, require less maintenance, and provide system longevity.

Field Experience

Issues: Failing check valves are often caused by installations too close to pumps and increasers. In addition, there is a tendency in design planning to oversize discharge pipes for future expansion which then require extreme reducers to fit the pump size. Both these issues create turbulent flow that can wear the disc and pin connections and cause premature check valve failure.

Pump station design with silent check valve installed five pipe diameter lengths from pump discharge.

Solutions: Ideally, the pipe distance between the pump and check valve should be calculated during the design phase of the project. For existing facilities, one solution is to move the check valve further away from the pump to achieve a more laminar flow, preferably five pipe diameters. If there are space limitations and moving the valve is not an option, then consider another style of check valve. Another solution is verifying the check valve is properly sized for the process conditions and, if possible, avoid utilizing extreme increasers.

Keys to Successful Check Valve Performance: The role of the check valve is to prevent backflow from damaging pumps in the process system. Check valves play a vital role in the successful operation of a facility. When designing a pumping system, it is beneficial to request a surge investigation from the valve manufacturer to determine whether the process conditions require a check valve or a pump control valve. If a check valve is required, then valve selection, size, installation and cost of ownership should be considered before specifying the valve. These key considerations will extend the life of the check valve, ensure proper protection of process equipment, and prevent an unplanned shutdown.

Lea Clauson is Technical Marketing Engineer for DeZURIK, Inc. and has worked at DeZURIK for over a decade in various application engineering and materials engineering roles. She earned her degree in Chemical Engineering from the University of Minnesota in . 

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  Without proper pressure management, high-pressure incidents can occur when pumps are turning on or off or when a valve suddenly closes, sending water hammer back through a piping system. Having the right valves to manage large fluctuations in water flow is one way that utilities can balance erratic flows and stay ahead of evolving community demands.

• CASE STUDY: Victaulic Brings Santa Barbara Desalination Facility Back Online in Record Time

  An innovative solution solves the challenge of missing subsea pipe 2,500 feet offshore and 50 feet underwater. The facility now supplies 30% of the city&#;s water supply demand.

• A Reference Manual on Elastomers

  The history and general application of elastomers in pipes, valves and fittings is the subject of the Manual of Practice developed by the American Water Works Association (AWWA).

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