samclem said:
The gate valves that used to be universally used in almost all home faucets/taps are terrible for not opening or closing after awhile. The newer quarter-turn ball valves valves are only a few bucks more and definitely worth the money whenever you get a chance to replace one of the old style gate or globe valves. Better flow rate, reliable opening and closing, etc. I've put them everywhere--shutoffs to the sinks and toilets, washer, hose bib, etc.
Each valve is designed for a different purpose, and each has its advantages & drawbacks.
When an old gate valve (or throttle valve) is replaced by a new ball valve, the "new" feature (especially materials) is probably more significant than the type of valve. But that doesn't necessarily mean that it's better (or will last longer) than the valve it replaced.
Ball valves & gate valves can leak across their seats much more easily than throttle valves. (Admittedly leaking into the washing machine is a lot better than leaking on the floor.) When a throttle valve starts leaking, you have several options for tightening/torquing its parts to keep things under control until you can get a new one... not so many options with ball or gave valves. With some faucets I'd rather replace seats & gaskets any day than have to rip out the old valve and put in a new one.
Ball valves & gate valves are absolutely destroyed by grit & abrasives. If it's just open then it's no problem. If it's shut then deposits build up on the face exposed to the fluid, and when it's opened those deposits are dragged across the seats. A few cycles of this will score the seats and it's time to get a new valve. There's nothing that can be tweaked or sealed.
Ball valves & gage valves aren't expected to throttle, so they're not designed for it. Using them as a throttle valve requires a lot of adjusting during operation but the problem is that the sharp edges of the ball valve's opening are dragged across the seats, wearing them out more quickly. A gate valve is a little better but is much more susecptible to leakage up the stem & bonnet while it's between "open" and "shut".
Throttle valves are great at flushing grit & abrasives through their parts with no damage, and their very rugged construction makes them tolerate a lot of operating use. They're a lot easier to adjust and repair as their parts wear out, while gate & ball valves tend to "break" without graceful degradation.
So... buy the valve that's designed for its intended purpose. If you're going to be operating it a lot and it needs to adjust the rate of flow, buy a throttle valve. (It usually has a rubber seat to seal the flow path.) If you're going to be turning something "on" or "off" once in a while, no throttling required but "no leakage" is important, then I'm biased toward gate valves. If you're going to operate something very infrequently or if you need something that quickly slams shut, then use a ball valve.
Washing machine valves with automatic leak-detector shutoffs, rarely operated-- ball valves.
Washing machines valves manually but rarely operated-- gate valves.
Washing machine valves open/shut manually & frequently-- gate valves or throttle valves. Gate valves can be cheaper by the unit but wear out faster.
Sink faucets-- rotary throttle valves.
Anything else... more expensive and more repairs. Admittedly the former isn't very important at today's home plumbing prices but if you don't enjoy rebuilding ball valves then don't buy those single-lever kitchen-sink faucet controls-- or make the person who thinks they're so cool be responsible for fixing them.
Submarines use all those types of valves (and a whole lot more) for air, water, hydraulics, and other assorted fluids.
Throttle valves are very popular because they have a lot of repair options before they have to be replaced. The average U.S. submarine probably has thousands of them and there are probably hundreds of designs. But they add flow resistance to any piping network.
Gate valves can isolate with zero leakage but when open have nearly unrestricted (low-friction) flow-- like the isolation valves in reactor coolant loops. They take a long time to shut and even when they're shut they can leak. But they're easier to design for rugged operations (especially across high differential pressures) and nasty environments. There aren't very many of them on submarines but they're used for critical applications and remote operation.
Ball valves exist for one purpose-- quick operation for fast isolation. That quarter-turn shut has saved a lot of lives when gate valves would still be cranking through 10-20 revolutions. Every seawater system has two ball valves at the hull openings for rapid shutoff. Just about every submarine ball valve I can think of was connected to a powered (electric-hydraulic) operator.
But after a couple decades' experience with them, I must admit that ball valves suck. They're probably the biggest hassle in extended repair periods, and off the top of my head I can't think of a single ball valve in any reactor primary or secondary piping systems-- just saltwater. Entire shipyard departments are devoted to ball valve repairs & replacement. The valves don't last anywhere near as long as their counterparts-- unless they stay open forever and are only shut once or twice a year for less than a day or two.
However they look cool and they're (mostly) really cheap.