Kitchen Cabinet, Post #21
Time to talk about the greywater tank dump valve. The way I usually camp is 2 - 3 days at one spot while I hike or bike then drive to someplace different and set up again. With a running water system I'd need a greywater tank to hold the effluent from the sink till I was ready to move on. Then after leaving the campground either dump the greywater tank in the road, if gravel road, or off on the berm if asphalt. That way I'm not burning extra gas hauling around a load of greywater. Of course this would be easy if I had a motorized dump valve and didn't have to get out of the van or even slow down.
If you price out a motorized valves you'll find them pretty much restricted to industrial use and very expensive. Time for some DIY. Went to Lowe's and wandered through the plumbing section looking for valves. Settled on a 1-1/2" PVC valve for around $11.00. It was either it or the 1" valve but decided on the 1-1/2" because it will dump faster and being as large as the drain size might help prevent clogging.
Got the valve so how to open and close it? I shopped around for a long while until I found a 12 volt automotive seat motor at American Science & Surplus
for $14.95. Ordered the motor to check it out.
Here's the motor and the PVC valve.
The reason I picked this particular motor is because of the threaded rod that extends from the gearbox at a 90 degree angle to the motor. Hadn't yet figured out how this was going to work but the gearbox would allow it to be more compact. According to the motor description the rod is a non-standard thread so I won't be able to just bolt something on to it.
How to join the motor to the valve? It's not like I could glue them together. After some more thinking I swung by Advance Auto and bought pair of 2-1/2" muffler clamps. They are around $3 each.
OK that gives me a way of joining something with the PVC valve. Now how to turn the valve? I'll make a cradle that slips over the top of the handle.
Could I weld the cradle to the threaded rod? Disassemble the gearbox to see what kind of gear is on the threaded rod.
It's a plastic gear on the rod so if I'm going to weld I'll have to be careful to not let it get too hot. Shorten the threaded rod with my band saw but wrap the gear in plastic first to prevent any metal shavings from clinging to it.
Create a couple of right angle metal "wings" that I can use to help connect the threaded rod to the cradle. Here I'm using the cut off piece of rod to check the gap between the wings.
With the wings welded to the cradle check the fit of the shortened threaded rod. Before welding I have to try to get the alignment as perfect as I can so the cradle doesn't want to shift on the PVC handle as it turns.
I'm going to welding directly on the threaded rod but can't let it get too hot. Got around this by instead of drawing a long bead using a series of almost like tack welds then allowing everything to cool down after each single weld. Tedious and time consuming but it worked.
If the PVC handle is going to have room to turn I'll have to move the muffler clamps farther away from the center. Another trip to Lowe's to buy the threaded adapters that screw into each end of the valve.
Start welding a framework onto the muffler clamps that will support the turning motor.
I would take the framework off the PVC before welding on it so not to melt anything.
One of the reasons this motor was such a good find for this project is this mounting point on the gearbox.
It's a perfect fit for the inside of a 1" square metal tube.
Typing this up makes me think I should order a couple more to have on hand since it is so easy to mount. Bet I'll find something else to make with them.
1/4" bolt fits the mounting hole.
How it will look when together.