Filtration - Version 1
Background
This filter is based on the lessons learned from the two filters I built for our pond. For this pond, my parents chose to use a larger pump that sits outside the pond. This meant some design changes, but it also allowed for more versitility in flows and configurations. It also gave me yet another chance to tinker with the design. ;-)
- Pump Location - Since the pump sits outside the pond, some plumbing changes needed to be made to allow for priming. Also, an inclosure was needed to house the pump and protect it from the elements.
- Split Flow - Since this pump can provide far more flow than the filter can handle, and the falls are bigger than the ones on our pond, I decided to split the flow. A small part goes through the filter and is returned directly to the pond. This means that the filter can run year round without worrying about the excess cooling that sending over the falls in winter can cause. The remainder of the flow is sent straight to the top of the falls and in is fully adjustible. This means that the rate of flow over the falls can easily be changed or even shut off in the winter if neccessary.
Design
(Click on picture for a full size version)
Reality
Here is a picture of the completed filter system. The enclosure for the pump was made from some shelves that Dad already had around, and he added doors to it after this picture to help protect the pump.
The intake pipe has a high spot that can trap air. The pump was unable to start the suction as long as the air remained in the pipe. To correct this, I added a small hole in the high point of the pipe that I used to bleed the air from the system. Once this was done I used a small sheetmetal screw, a piece of rubber liner, and some plumbers putty to seal the hole. It worked great, and so far, no air leak from the hole.
On our pond, there was very little pressure in any of the pipes, so it was not neccessary to glue the joints. On this one, the intake pipe had to be glued to prevent air leaks that would cause it to lose the prime. As I also learned the hard way, there is considerable pressure built up between the pump and the valves. Shortly after getting the system up and running, it blew the pipes apart near the valve that feeds the filter. Water was going everywhere, and my brain just shut down. I stood there yelling "Sh*t, sh*t, sh*t!" After what seemed like forever, but was really only a few seconds, I recovered and unplugged the pump. Now all of the pipes with any pressure at all are glued with PVC cement.