Wed Sep 20, 2006 2:10 pm
The silicone diaphragm is a nice piece of work. Compared to modern, single hose regs, the double hose Royal Aquamaster is a very stable mechanism with stiff but reliable components. The single hose, with its smaller second stage diaphragm, is at a theoretical disadvantage to the double hose such as the RAM. In order to compensate, the engineers responsible for designing the second stages of single hose regs have had to design mechanisms which are potentially unstable, fragile and lately, very complex. They do this to overcome problems such as inhalation resistance, flow instability, and freezing. Thus, yearly inspections are recommended to adjust, inspect or replace certain second stage parts such as springs, the poppet valve O rings and the very thin diaphragm. In contrast, the components in the Royal second stage have been known to function reliably for decades without recourse to replacing or adjusting anything. Inspections consist mainly of checking for corrosion. It is not surprising that yearly maintenance of single hose involving disassembly are a routine matter. This fact alone puts the reliability of single hose regs in question (if it ain't broke, don't fix it). Any time a regulator is disassembled beyond simple inspection the risk for human error increases. Regarding the double hose RAM, there is a penalty for such comparative stability and safety. The second stage components are oversized and rugged but somewhat stiff in operation. This applies to the diaphragm and poppet valve spring. Retuning the interstage pressure and spring rates is an option but has limits, otherwise, the double hose could be subject to the instability problems which characterise the single hose reg, referring to the need for eternal maintenance and performance checks. However, one area which can and has been addressed is to adopt the single hose solution of using a more flexible diaphragm. Thus, although the new silicone diaphragm for the RAM remains thicker than a single hose diaphragm, the ratio of surface area to thickness in the RAM diaphragm is quite large making it effectively thinner and potentially more flexible. When cast in 30 duro silicone, the RAM diaphragm assumes a great deal of flexibilty indeed. Thus, an engineering ploy used in the single hose reg, the flexible diaphragm, is answered by Brian's Royal Aquamaster diaphragm.