PSV Manufacturers 3

[AKoilngas]

Hello All,

I've recently been put in charge of selecting a PSV for use on a Coalescing Filter and Fuel Gas System at our client's small Natural Gas Processing Facility. I put out a Request for Quotes to a few vendors on the PSVs that I sized. The returned bids surprised me as they looked similar to this.

Manufacturer A's PSV - $200
Manufacturer B's PSV - $300
Manufacturer C's PSV - $2000
Manufacturer D's PSV - $2500

These are the same PSV's as far as I can tell; same sizing, same materials of construction. And when I asked the vendors about the price discrepancy, they are of no help. Finally the question...

What am I losing/gaining by picking one or the other? More specifically, can anyone give me comparative experiences between a Taylor or Mercer valve compared to the higher priced Consolidated or Crosby valves? Is it the valves that differ or do I need to find myself different PSV reps?

Much Appreciated
-AK Oil'n'gas

 

[jay165]

You're correct to be suspicous, given the spread in prices. To be honest, I've never heard of Mercer or Taylor. They "look" okay from viewing their respective web sites. I've only used A-G, Consolidated and Farris.

One thing I've found when faced with big ranges in quotes are the different levels of testing and material tracibility that are supplied. (I'm assuming the valves are the same size, type and materials). If you require documentation, mill certs, test certs, etc you may have to pay more, although 10X seems excessive. If you're buying through a middle man (rep) it may be his mark-up. I would go back and try to find out why the expensive ones are so much more.

If you could, I'd like to hear the explanation (if there is one!)

 

[mb44]

Just be careful remember if you choose the wrong one and it blows the entire plant up its going to cost a lot more than US 1800 to put right.

You also need to consider the PSV's vendors experience in natural gas plants etc.... have they got good quality control... can you get the documents you require.. what about spares....and calculations

There will be a difference between the valves, other wise the likes of Crosby etc would never sell any PSV's.

I often find its horses for courses with other items, you have to look at where the plant is located, the criticallity of the device, can you afford it to fail do you have duty/standby. I mean ball valves for example are a classic example what appears on paper to be the same valve will range from 500 USD to 5000 USD. when you get them however there will be a general build quaility difference, one will feel nicer and better quailty than the other.

Look at cars or clothes.... a Mercedes costs 3* the price of a ford...both have the same engine size, same material, leather seats , air con etc on paper so why would you want a Mercedes. What about shirts some cost 1 USD others 100 USD yet both are 16" collar and white.

But to get back to the engineering for a saftey critical device don't take chances, tried and tested is best.....or you tell the operators wife+kids when it all goes wrong

Remember it is unwise too pay to much but even worse to pay too little. If you pay too much the worst that happens is you loose a little money. If you pay too little the item you bought at worst doesn't work and you loose everything.

The basic laws and rules of business restrict you from paying a little and getting a lot. If you deal with the lowest it is worth adding some for the little extras that will be required. If you do that you could probably afford the more expensive item in the first place.

Many procurement managers would do well to remember this

MB

 

[stewbaby]

Interesting spread on price...but my opinion is that the old saying is true "you get what you pay for". We only use Consolidated and have gotten there over many years of attrition (try and learn, try and learn).

On a side note, if you don't mind saying, who are you buying your coalescing filter from?

 

[Montemayor]

AKoilngas:

Very briefly, blow away the $200 and $300 PSV if you are talking about a 1.5"-2" size or larger. Common engineering sense tells you that a reliable PSV of that size can't cost the equivalent of 3 engineering man-hours.

The $2,000 range is what I would expect for a 2" PSV from a recognized and serious fabricator like Farris or Crosby.

I fail to see how any engineer can make any comment on the price range of a PSV without knowing the type and size of PSV involved. Are you talking pilot? balanced? un-balanced? Stainless? Cast Iron? Without this detail, no one can make a credible judgement. What I can state is that I would expect to pay approx. $2,000 for a balanced bellows, 2", SS Farris with appropriate trim for a set pressure around 300 psig.

Art Montemayor
Spring, TX

 

[AKoilngas]

Montemayor, the specifics:

The PSVs in question are all Conventional, Carbon Steel body, SS trim, H orifice (0.785sqin), 2"x2" NPT, set @ 1415psig, with a relief load of apprx. 50,000 lb/hr of natural gas (0.5617 SG). The Crosby has a metal seat and the Taylor has a viton ring seat (The viton ring provides a tighter shut-off after the PSV has popped, at least this is my understanding)

Is $2000 still an expected amount to pay for a Conventional PSV of these specifications?

 

[Montemayor]

AKoilngas:

Yes.

I would not place confidence on the Viton soft seat resealing at 1,415 psig. I've always specified metal-to-metal seating when dealing with compressed gases in excess of 300 psig and 200 oF. That's my personal experience; others may vary their preference and expectations.

However, now that we've got the "rest of the story", allow me to expound on the subject that most experienced engineers will point to the importance of quality, reliability, and experienced suppliers for this type of application. Quality lapping and grinding a metal-to-metal seat successfully is a key note feature in recognized suppliers of PSVs. Using a "soft" seat and pulling an "end run" on the necessity of quality machining is, in my opinion, naive optimism. Like the other respondents to this thread, I also have experienced the resultant value of sound and reliable engineering from manufacturers such as Farris, Consolidated, and Crosby. I hope this experience is of some help to you.

Art Montemayor
Spring, TX

 

[chemdesign]

I would expect to pay at least $2000, maybe more. Also note a 2" outlet is not a "standard" size for an H orifice. Typically outlet is larger than the inlte. My API charts show the minimum outlet for a H orifice is 3".

 

[AKoilngas]

Montemayor,
Thank you for the reply.

Stewbaby,
We have purchased Anderson Filters from Clark-Reliance and also a filter from Peco Filters. These have all be Coalescing Filters sized from 15MMSCFD to 30 MMSCFD natural gas. They have performed very well, no complaints yet. I'd be happy to provide more information if you're interested.

 

[stewbaby]

Thanks AKoilngas, my application is different...water from diesel, but wanted to see whose seperation equipment you were happy with. This will be our first coalescer and looks like we'll go with PECO due to price and the references we've checked.