Hello Everyone,
A couple of years ago, I had designed a sequencing valve to fill 6 different grow beds in my
aquaponic system. It has been running continuously for 2 years without clogging with solids or
needing maintenance. The micro-switch used for the indexing positions has finally worn
out.
I was going to patent the design, but it’s too expensive with too little return so I’m
now sharing the design. Also, a good commercial sequencing valve that has a completely different
style of indexing is available which works well. While I have it dismantled, I will replace
the latex tubing since it is starting to rot.
The indexing mechanism uses a windshield wiper motor running on 5 volts and has a 6 sided
cam that a micro-switch travels around. Power is applied to the normally closed pole which
will turn on the motor through the common pole. When the cam moves to a high position
the switch opens and turns off the motor. When it’s time to move to the next position,
power is applied to the normally open pole, turning on the motor again until the switch
travels to the next area of the cam.
There is also a secondary cam that has one indent at the first position. This is to allow
the controller to reset the valve to position one in the event of a power failure.
Removing the cover exposes the internal workings. There are 6 latex tubes that are located around
a cam with a small ramp cut into it. As the cam rotates, the ramp area will push against
the slider which will pinch and hold the tubing closed. As the cam continues, the next positions
slider will spring open. One nice feature about using a pinch valve is that there are
no seals needed. The mechanics never touch the water!
The water is fed into the valves through a ring with 6 tee connectors. The latex tubing
is attached to each of the tee’s and a zip tie is attached to insure it won’t slide
off the barbed fitting.
The
6 latex tubes are inserted through the base cover. They are then inserted through the
center ring section.
The master cam is placed onto the rotating shaft. There is a wing-nut connected to the
shaft and the wings are used to anchor the cam to the shaft.
Latex tubing is very flexible and pinches closed easily. The sliders that pinch the
tubing closed have a peak on it. The anvil on the other side has a valley cut into it.
When this area pinches the tubing, it also folds it a bit which creates a tighter seal.
The anvil rests on a screw so it can move around a bit so the slider and anvil will
always align while it is being pinched.
The final cover is placed over the mechanism and the tubing pulled through. There are 6
bolts that pass through the entire assembly which hold it together.
Here is the entire sequencing valve installed in the greenhouse. I hope you enjoyed this
video and we would appreciate it if you visited our web site at www.BigelowBrook.com for more
details about our products. Thanks for watching!