Why not replace dump valves with a ball valve?

[Troutboy]

I read much about how the gate valves used for gray and black tank dumping get clogged or don’t work.

I’m in the wastewater business, build many water and wastewater treatment plants for municipal and industrial clients.

ball valves are more reliable for straight on/off applications. They are more robust and because of design, they don’t plug seals as easy.

Has anyone replaced the cheap gate valves with something better?

Only thing I can ,think of is cost, as a good ball valve will cost 5x that of the cheap gate valves (around $60).

Thanks

[rmkrum]

Physical size of a ball valve may also be an issue. The usual cheap gate valve does not occupy much space for a given diameter. Maybe a half inch to an inch max between the flanges. A 3” ball valve would be at least 4” or more between the flanges.

I know my dump valves are very tight together. No room for two 3” ball valves, so I could not retrofit a pair of ball valves in the space between my tanks. Sad, because it would be a lot better.

Note that I carefully avoided any references to a pair of.....

[Troutboy]

You can get some compact ones, but I see your point. I’ll have to look at it. The gates definitely have an advantage there.

Might have to do a complete redesign to fit them balls in....

A pair, lol....

[rmkrum]

Was seriously trying to not go with that joke....[emoji3]

Reminds me of The Scoutmaster’s prayer when the campfire skits begin, “Keep it ‘G’, keep it ‘G’...” Been there done that over my 15 or so years as a Scout Leader....

[nddstl]

I was wondering if either of you ever got a response to your ball valve question? I need to replace my waste gate and it looks like its going to be a pretty serious undertaking. I will have to cut a hole in the bottom of the trailer to reach the valves which Im not excited about. If Im going to do this I would prefer to replace the two valves at the same time with ball valves that will last more than a few years.
Thanks for the help.

[GMFL]

I vote Rich to work out the details and I’m all in after that.

[TG Twinkie]

It makes sense to me. The biggest issue would be how to operate (turn) the handle on the valve.
It would be relatively easy on the black water system in my '74 Argosy since the current valve is in the trunk.
The grey water is a totally different story.

[ROBERT CROSS]

How would you open close, all the balls I've seen have been lever operated, is there such a thing as a push/pull ball valve?
On the FWT 1/4" works great. 👍

Bob
🇺🇸

[Protagonist]

Originally Posted by ROBERT CROSS

is there such a thing as a push/pull ball valve?

Not really.


However, you could attach a quadrant (quarter-circle) in place of the lever so that you are pushing/pulling in an arc instead of a straight line, and attach a push-pull cable to the quadrant. Then the limiting factor becomes how much effort it takes to move the quadrant and thereby move the ball valve.


It sounds complicated, but many boat rudders work exactly that way but on a larger scale.


And of course you would need even more volume, not only for the ball valve itself but also for the quadrant.


Another possible option would be to use a rack-and-pinion instead of a quadrant, and motorize your new ball valves by using a small 12vDC motor to turn the pinion gear. Then you don't have to push/pull at all, just flip a toggle switch. Limit switches at each end of the rack's travel would shut off the motor to keep it from burning out the motor or stripping the pinion gear.

[OTRA15]

If it ain't broke, don't fix it.

If you think cleaning a mucked-up gate valve is messy, try cleaning a ball valve with the same zhlt in it.



Keep it simple, Stu...

[Protagonist]

Originally Posted by OTRA15

If it ain't broke, don't fix it

The engineering way is, "If it ain't broke, keep fixing it until it is!"

[OTRA15]

That's the ticket!

[rmkrum]

Or, simply "overkill engineer" the device until it takes a 14 page book of instructions to operate, a team of highly-trained technicians, computer programming, safety inspectors, pyrotechnic devices, and a three inch diameter wire harness interconnecting all the parts. Then, to make it more interesting, make sure all the wires in the harness are the same color. Oh, wait, this is not for Mil-spec or spaceflight hardware...it's just a travel trailer.

Nevermind!

Seriously, the blade-type dump valve is probably the simplest, if not the cheapest (which is why RV manufacturers use them) way to open and shut a tank drain. Motorized valves just tend to complicate things...unless you are old and crunchy and don't want to bend over to operate them. I'm not quite crunchy enough to go to motorized valves, but eventually it might prove handy.

And the newest engineering term for the group is "Maintenance-induced failure (MIF). It turns out to be a real thing. Some maintenance procedures are more likely to damage or wear out a piece of hardware than normal operations. The recent news story where some technician in Belgium managed to destroy a bunch of aircraft by accidentally firing a 20MM cannon on the aircraft he was working on is a fine example. Last I looked, it's never a good idea to do maintenance on a fully-armed aircraft's electrical system...funny ("funny peculiar, not funny HA HA" **) stuff can happen.

**50 points to whoever can provide the source of the (sort of) quote...

[lynnsr]

I’ve had campers and been camping in them for 25 years.

Have never had one gate valve problem, or replaced one.

Lynnsr

[Protagonist]

Originally Posted by rmkrum

And the newest engineering term for the group is "Maintenance-induced failure (MIF).

The inevitable end product of "percussive maintenance." Which means, "If it don't work, hit it with a bigger hammer until it does."

[Bill M.]

I have rebuilt the 4 dump valves on 2 trailers and then replaced 2 of them on one trailer. So they can cause problems. Does someone actually make a cheap, lightweight ball valve? I just hope we can keep getting decent gate valves. Ball valves are good for partial flow and control. But if it is opened all the way it looks like a gate valve should be fine for dumping. One way to work a ball valve would be a solenoid and open it electrically.

[rmkrum]

My absolute favorite was a turn-key 1970's vintage computer system that included a lot of mechanical hardware. It even came with a ton of neatly boxed and labeled spare parts, a nice fancy oscilloscope, and a set of tools.

Opened up the tool box when I got it. The top tray contained at least 6 different types of hammers...

Found that I needed every darn one of them at some point...and yes there were many maintenance-induced failures.

The best example was the software used to test and diagnose the condition of the reel-to-reel digital tape drives. Running the test was absolutely required once a month. It tended to beat the heck out of tape capstans, bearings, and pinch rollers, to the point that it often broke things during the diagnostic run, that otherwise worked fine during normal operation. Then out came all the tools and parts, as I worked for hours to replace the damaged parts, re calibrate the whole sorry mess, and precisely adjust the replaced mechanical stuff. And yeah, the hammers got used a lot.

Then next month the mess started all over again.

[AlinCal]

The holding tank valves are Knife Gate valves and suited to their task.
I was the piping foreman on a sewer treatment facility expansion for the city on Paso Robles in the early 90's and never once saw a ball valve used in waste water piping, typical was knife valves, gate valves and butterfly valves, a ball valve would not be a good choice.

[perryg114]

The gate valves work pretty well considering. Sometimes they outlast the trailer they are installed in. Most RV related items are designed for a 10 yr life and that is with occasional use. If you full time or camp a lot, something is going to fail. I have lived in RV's before and the stuff holds up pretty well. Flushing black water tanks and valves occasionally is a good practice. Also using hair strainers in the shower will prevent some problems. Rubber seals and hair don't get along. I have also had problems with hair tangling up the impeller in my external macerator pump.


Ball valves are great for supply and drain applications.



Perry

[wulfraat]

The gate valve on the black tank in my 2017 30’ international is leaking now after 1.5 years. Slow leak. Yuck! Last one lasted 8 on my last trailer before I sold it.

Hopefully it’s not too painful to replace on a 2017... 1/2 of the valve is located inside the aluminum tank covers......