Distribution valve and cam mechanism
An improved multi-port water distribution valve is disclosed together with the improved cam mechanism that significantly enhances the efficiency and effectiveness of the valve when used to distribute water to multiple sets of pop-up cleaning heads incorporated into the in-floor cleaning system of a swimming pool. Two forms of prior art distribution valves are disclosed as is the improved cam mechanism that, when used to replace the prior art cam in these devices, significantly improves their performance. Comparative data is provided demonstrating the results achieved with two different prior art valves operated with and without the improved cam. Embodiments of the invention suitable for use in existing six-port and five-port distribution valves are disclosed.
1. In a distribution valve having a drive shaft, an input port and a plurality of valve-operated output ports that are selectively opened to allow fluid flow from said input port, wherein the improvement comprises a cam for controlling the fluid flow through adjacent pairs of said output ports, said cam including:
(a) a cam plate having a center of rotation connected to the drive shaft of said distribution valve;
(b) a leading cam surface to control the opening of said outlet ports, said leading cam surface extending circumferentially from said cam plate at an included angle between about 46 and 52 degrees;
(c) a trailing cam surface to control the closing of said outlet ports, said trailing cam surface extending circumferentially from said cam plate at an angle of between about 54 and 66 degrees; and
(d) a transitioning cam surface extending between said leading and trailing cam surfaces to selectively maintain the outlet ports in their open position and to allocate flow through two adjacent outlet ports as one port closes and the adjacent port opens.
2. The distribution valve of claim 1 wherein the angle formed by the leading cam surface is about 48 degrees and the angle formed by the trailing cam surface is about 56 degrees.
3. The distribution valve of claim 2 wherein forces exerted on said leading and trailing cam surfaces include opposite circumferential force vectors and wherein the circumferential force vector exerted on the trailing surface exceeds the opposite circumferential force vector exerted on the leading surface.
4. The distribution valve of claim 3 for use in a distribution valve having more than three and fewer than seven outlet ports.
5. A cam for use in controlling the flow through a rotating distribution valve having a drive shaft, an input port and a plurality of valve-operated output ports, said cam comprising in combination:
(a) a cam plate having a center of rotation with a connection to engage the drive shaft of said distribution valve;
(b) a leading cam surface to control the opening of said outlet ports, said leading cam surface extending circumferentially from said cam plate at an angle between about 46 and 52 degrees;
(c) a trailing cam surface to control the closing of said outlet ports, said trailing cam surface extending circumferentially from said cam plate at an angle of between about 54 and 66 degrees; and
(d) a transitioning cam surface extending between said leading and trailing cam surfaces to selectively maintain the outlet ports in their open position and to allocate flow through two adjacent outlet ports as one port closes and the adjacent port opens.
6. The cam of claim 5 wherein the leading cam surface extends at an angle of about 48 degrees and the trailing cam surface extends at an angle of about 56 degrees with respect to said cam plate.
7. The cam of claim 6 for use in a distribution valve having more than three and fewer than seven outlet ports.