Ball valves are the workhorse of instrument isolation. A quarter turn and the line is open or shut, and anyone walking by can tell which by looking at the handle. Because they're so common, they also get ordered in a hurry. After 20 years of handing them across the counter, here are the five things I'd want you to check before you put one in your system.
1. Use It for On/Off, Not Throttling
A ball valve is built to be fully open or fully closed. Leave it cracked partway and the flow cuts across the edge of the ball and the seats. Over time that wears the seats and the valve stops sealing when you finally need it to.
If you need to control flow, not just stop it, use a needle or metering valve for that job and keep the ball valve for isolation. You can browse options in our needle valve collection.
2. Match the Seat Material to Your Pressure and Temperature
The seats are what actually seal, and they're usually a polymer. PTFE-type seats are common and work well for a lot of general service. Higher temperatures or harsher media may call for a different seat material. CNG (compressed natural gas) rated ball valves will see high pressure at low temperatures. Peek seats are ideal for this application.
Here's the part people miss: a valve's pressure rating drops as temperature goes up. Don't just read the top number on the data sheet. Look at the pressure-temperature chart for the seat material and confirm your actual operating conditions fall inside it, with some room to spare.
3. Pick the Right Flow Pattern and Body Style
Most jobs need a simple 2-way valve: on or off. If you need to send flow to one of two places, a 3-way diverting valve can replace two valves and a tee, which means fewer connections and fewer leak points.
Think about maintenance, too. On a swing-out ball valve, the center body can be swung out of the line to service the seats and seals without breaking the end connections. On a line you open often, that can save real time down the road.
4. Get the End Connections Right
Double-check what you're connecting to before you order. Is it tube or pipe? Fractional or metric tube? Male or female NPT? A 6 mm end and a 1/4" end look close on a crowded shelf, and they don't mix.
If the valve has tube fitting ends follow that manufacturer's make-up instructions. Our compression tube fittings page has the matching connectors and adapters.
5. Plan for the Handle, Orientation and Lockout
On most ball valves, a handle in line with the pipe means open, and a handle across the pipe means closed. Make sure the handle has room to swing a full quarter turn without hitting a wall, a support or the valve next to it.
If that valve will be part of a lockout/tagout point, ask about a lockable handle up front. It's a lot easier than trying to rig something in the field. And valves that sit in one position for months can get stiff, so it's worth including them in your routine checks.
We're Here to Help
A-Best Industrial Inc. Fittings, Valves, and Tubing is an authorized DK-Lok distributor, and we stock instrument ball valves in a range of sizes, end connections and materials. See what's available in our ball and plug valve collection, or learn more on our DK-Lok page.
Not sure which valve fits your application? Call us at 310-833-3353 or email sales@abesttube.com. We'll talk it through with you and get you the right part the first time.