2 Stage Decompression
The objective is to gradually reduce the system pressure until the threat of decompression shock no longer a factor and at that point of the pressure reduction cycle, open a second valve with greater flow capacity which will allow the cylinder or vessel to complete the drain to reservoir (tank) cycle.
The relationship of decompression to pressure is complicated by cylinder or vessel diameter, length and diameter of hoses in the system. Each system may be unique and safe stage two decompression pressure should be determined based on testing by the OEM and then determining a safe PSI for each system design.
|Product||Spec Sheet No.|
|SD2 Housing for Two Stage Decompression||1201268|
|SD842 Housing for Two Stage Decompression||1203114|
Used in conjunction with above housings for 2 stage decompression
|Air Pilot, 1-1/2 GPM, Hex Base, N/C 1 to 2, Pilot to Open, Ratios to 255:1, Uni-directional||1201235|
|Air Pilot, 1-1/2 GPM, Tamper-Resistant, N/C 1 to 2, Pilot to Open, Ratios to 255:1, Uni-directional||1201457|
|Manually-Operated, 1-1/2 GPM, Hex Base, N/C 1 to 2, Push to Open Force (PSIx.013+15PSI)||1201499|
|2 Way, N/C, Pilot with Manual Override, Orifice Option||1202392|
|SD2-3S Housing||Spec. Sheet No. 1201268|
|82H0151681 Stage 1 Valve, 168:1, with .015 Orifice||Spec. Sheet No. 1201235|
|84H2090191 Stage 2 Valve, 19:1||Spec. Sheet No. 1201653|
Apply air pilot signal of 45 to 55 PSI to both Stage 1 and Stage 2 valves simultaneously. The Stage 1 valve will open first due to the pilot to system ratio (effective pilot pressure 35 PSI X 168 pilot ratio = 5,880 which is well above the starting pressure of 5,000 PSI.
Stage 2 Valve will open for increased flow when system pressure reaches approximately 650 PSI (effective pilot pressure 35 PSI X 19:1 Pilot ratio = 665 PSI). Both valves will remain open as long as pilot pressure is applied.
To increase or decrease the pressure at which Stage 2 Valve opens, increase or decrease the pilot pressure. Actual tests should be conducted to determine the ideal settings.
Doering Company offers a range of pilot to system ratios. We also offer a range of orifice diameters to best suit your application.