Abstract: A device is provided for use in analytical instrumentation that provides continuous transfer of a known molar quantity of gas from a source having an unknown gas mixture and varying pressure. In addition to the upstream and downstream paths of typical flow control devices, the device has a midstream path to introduce a carrier gas at a known elevated pressure. The device has at least three equal-volume ballast vessels and a valve arrangement to cycle the ballasts through at least three states: fill, equilibrate, and empty. The ballasts fill with the upstream gas, pressurize and equilibrate at the midstream pressure, and empty to the downstream path. The cycle of each ballast is timed in phased relationship to the other ballasts to keep the flow relatively uninterrupted; as one fills, another equilibrates, and another empties.

Abstract: A rotary dosing device for use in analytical instrumentation quickly transfers a sequence of precise molar quantities of gas from a primary stream into a secondary stream. The device has a rotating chamber with dosing ports that cycle through three states: fill, equilibrate, and transfer. The device cycles in an overlapping manner such that as one dose volume fills with gas from the primary stream, another equilibrates at a known pressure and temperature, and another transfers its contents to the secondary stream. The device initiates its operation so that the first transfer in a sequence is a properly filled and equilibrated dose from the primary stream. Rather than cycling a single dose volume through the three states multiple times, the overlapping operation of the rotary doser enables multiple precise molar quantities of gas to be transferred in one-third the time.

Abstract: A device is provided for use in analytical instrumentation that provides continuous transfer of a known molar quantity of gas from a source having an unknown gas mixture and varying pressure. In addition to the upstream and downstream paths of typical flow control devices, the device has a midstream path to introduce a carrier gas at a known elevated pressure. The device has at least three equal-volume ballast vessels and a valve arrangement to cycle the ballasts through at least three states: fill, equilibrate, and empty. The ballasts fill with the upstream gas, pressurize and equilibrate at the midstream pressure, and empty to the downstream path. The cycle of each ballast is timed in phased relationship to the other ballasts to keep the flow relatively uninterrupted; as one fills, another equilibrates, and another empties.

Abstract: A rotary dosing device for use in analytical instrumentation quickly transfers a sequence of precise molar quantities of gas from a primary stream into a secondary stream. The device has a rotating chamber with dosing ports that cycle through three states: fill, equilibrate, and transfer. The device cycles in an overlapping manner such that as one dose volume fills with gas from the primary stream, another equilibrates at a known pressure and temperature, and another transfers its contents to the secondary stream. The device initiates its operation so that the first transfer in a sequence is a properly filled and equilibrated dose from the primary stream. Rather than cycling a single dose volume through the three states multiple times, the overlapping operation of the rotary doser enables multiple precise molar quantities of gas to be transferred in one-third the time.