The ROSS Poppet Valve ....a ROSS specialty from the beginning
Positive Sealing
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Inlet air pressure forces the inlet pop-pet upward, pushing the poppet seal firmly against the seat. The higher the inlet pressure, the greater is the sealing force. Note that the seal is engaged perpendicular to the seat; there is no sliding action to damage and wear the seal. |
Self Cleaning
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The flow velocity for a given volume of air is dependent upon the area through which it is flowing. The smaller the area, the greater the velocity. In our poppet valves, the smallest flow-through area is across the poppet's seal and seat. This produces a very high velocity which blows all dirt and foreign matter out of the seat area for a virtually leak-proof seal. |
Self-Compensating for Wear
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Because of the poppet valve's design, any change in the height of the valve seal (due to burnishing) is automatically compen-sated for by an equal change in the length of stroke.> Therefore, the sealing force remains constant over the entire life of the valve. |
Sure Shifting
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Pilot air pressure, working on a large pis-ton, produces a very strong actuating force. High velocity air flow begins at the instant when the inlet poppet moves off the seat; flow enhances actuation right from the start. There is minimal sliding of seals in a poppet valve (sliding seals are highly prone to varnish). When pilot air is exhausted, the inlet pree-sure produces an extremely strong up-ward force, reliably shifting the valve to a closed position. |
Table -Comparison- 27series with 21 series
| Items | 27 series | 21 series | ||||
|---|---|---|---|---|---|---|
| Condition to use | Normal | Low Temp. | High Temp | Vacuum | ||
| Temp | Ambient ［℃］ | 4 to 50 | -40to 50 | -17to 122 | -40to 50 | |
| Media ［℃］ | 4 to 80 | -40to 80 | -17to 150 | -40to 80 | ||
| Main material of internal | Acetal resin | Aluminum alloy/Stainless steel | ||||
| Seal Material | Piston seal | NBR (Buna-N) | NBR (Buna-N) | FKM | NBR (Buna-N) | |
| Inlet seal | Polyurethane | NBR (Buna-N) | FKM | NBR (Buna-N) | ||
| Exhaust seal | NBR (Buna-N) | NBR (Buna-N) | FKM | NBR (Buna-N) | ||
| Bushing material | Nylon | Nylon | Polimide | Nylon | ||
| Material of manual override | NBR (Buna-N) | Aluminum alloy | ||||
| Pipe size | Exhaust port | 1/2"～1-1/2" | 1-1/2"～2-1/2" | 1/2"to1-1/2" | 1/2"to2-1/2" | |
| In & Outlet port | 1/4"～1-1/2" | 1-1/2"～2-1/2" | 1/4"to1-1/2" | 1/4"to2-1/2" | ||
| Pressure | Supply [MPa] | 0.1 to 0.98 | 0.2 to 0.98 | 0.2 to 0.98 | Vacuum to 0.98 | |
| Pilot supply | Internal and External | Internal and External | External | |||
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