Valve Manufacturer Advice | Eng-Tips

Greetings,

I am designing a small batch chemical plant and for the first time ever getting into the real details of piping costs. The piping systems I am considering are 2 in dia or less and low pressure/temperature where stainless steel is more than adequate corrosion protection. Right now I am looking at basic hand valves for the lines (ball, gate, globe, and maybe a butterfly or two) and am amazed at how many valve manufacturers there are out there. I am also very surprized at the huge variation in cost for the same size/type of valve in the same "class" of service. The valve descriptions do not offer any explaination for the cost differences.

I know this may be a difficult question but can anyone offer some manufacturer advice for basic hand valves for low pressure mildly corrosive service (316/304 SS). I am just looking to narrow the playing field here and not choose somthing very cheap or very expensive without a good reason.

Any experience passed along will be greatly appreciated.

JoeChem Oh come on- you ALWAYS get LESS than you pay for, or else someone isn't making a profit!

You're experiencing to some degree the phoney diversity offered by the marketplace.

Low pressure/temperature, small size (< 2"), and either 304 OR 316 are acceptable? Investment cast commodity ball valves are the usual solution for blocking, and cast globe valves for throttling. These are COMMODITY valves, and dirt cheap. Literally hundreds of "brands"- every stainless piping supplier name-brands some in this part of the world.

Butt weld or flanged are going to be overkill. You're looking at either threaded or socket welded, unless there's something about your process you're not telling us.

Need the connections to be welded? Three-piece construction is the norm, so you can easily disassemble prior to welding, and later for maintenance. Threaded is OK? Then you may save a few bucks with 2 pc for valves you don't expect to service/repair frequently. Really trivial services like instrument air blocks etc.? One piece reduced port (end entry) saves a few bucks more.

Most of the cast valves are CF8M, which is a cast 316 grade. If you get these valves with socket-welded ends, you will get a threaded valve with threads removed- the same for the 150# fittings typically used up to 2" in these services. Note that CF8M is NOT 316L- it is NOT low carbon! If you weld it, you may have carbide precipitation and lose corrosion resistance in the HAZ. The low carbon grade CF3M is MUCH less readily available.

Cycling a lot? Then you may want live loaded packing. This can double the cost of the normal el-cheapo three-piece ball valve, but may be worth it depending on your cost of down-time to do repairs/replacement.

These are a commodity product, which means they're pretty much all the same within reasonable expectations of performance. Yes, there are some WOG and some WOG versions (makes no difference to you, though!), some with through-body bolts and some with only bolt tabs on the body etc. Some with proper actuator mounts, handle extensions available etc., and others without. Some even offer more than one seat material. But for your service it probably doesn't make a hill of beans difference which of these you choose. Sure, they all try to differentiate themselves from one another by some subtleties, and some brands may actually have more quality control than others, but how you'd ever really know the truth from the sales bum-fodder is tough to determine. Well Joe,
This is a reassuring request to my mechanical colleagues from one of our arch-enemies, the process hotshots! Perhaps you now understand what we do?

Jokes aside, the difference would be largely due to whether compliance is needed with the major equipment standards such as API, ASME or BS (which have very good, but rigorous standards for small bore valves).

As you would know, the requirement for these standards is given in the particular piping code to which your plant is, or will be built.

I have known instances where vendors have been trying to peddle half inch ball valves in stainless steel (well they do look silver), but don't expect to see any reference to a design standard. These, and bronze equivalent valves will sometimes go for as low as five bucks each, but don't expect to use them on anything more hazardous than mains pressure water.

In short, specify an applicable standard and ask to see certification if in doubt.

1. VALVE FEATURES: The two piece full port ball valve has very low fluid resistance, with its coefficient equal to that of the same length of pipe segment. The flows direction of the medium is not subjected to installation restrictions, ensuring rapid flows due to the minimal fluid resistance.
2. ANTI CORROSIONESS: The sealing between the ball valve and the gate is isolated from the medium, so it will not be eroded by the medium it guides.
3. BROAD APPLICABILITY: The valve is adaptable to a wide range of diameters, from a few millimeters to several meters, and can be used under high vacuum or high pressure conditions. By rotating the ball 90 degrees, the flows can be cut off entirely.
4. LARGE CAPACITY: The valve has a working pressure rating of WOG, a maximum of psi for water, oil and gas, with a broad temperature range from ‑20℃ to 200 ℃. It can handle both liquid and gas media.
5. VERSATILE USAGE: This ball valve is ideal for a range of applications, from gardens, water pumps, external water taps, rainwater collection, pipelines to machinery, industrial equipment, and drainage systems.

Specification:
Item Type: 2 Pieces Full Port Ball Valve
Material: 316 Stainless Steel
Connection Type: Female thread
Nominal Diameter: DN15 (1/2 inch)
Drive Mode: Manual
Working Pressure: psi (WOG)
Operating Temperature: -20℃ to 200℃
Nominal Pressure: 1.6MPa
Strength Test Pressure: PT2.4MPa
Applicable Medium:
Q11F-(16-64)C water, oil, steam
Q11F-(16-64)P nitric acids
Q11F-(16-64)R acetic acids

packing list:
1 x Ball Valve

You will get efficient and thoughtful service from Cencho.

If you want to learn more, please visit our website wog ball valve.

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