Abstract: A multi-port valve uses a flexible sample tube to selectively intercept gases flowing from inlet ports into a common manifold space. The manifold space is placed under sufficient vacuum to insure that gas samples will be selectively received by the sample tube when the sample tube is placed in close proximity to the selected inlet port to be sampled. The sample tube is arranged so that gases to be sampled from the selected port wash over the entrance end of the sample tube so that contaminated or mixed gases from the manifold space are prevented from entering the sample tube. The sample tube is mounted to pivot inside a valve body and is moved by a sample tube guide which rotates inside the valve body to selectively align the sample tube with the inlet ports. The valve body may be sealed by a cover through which the valve guide is driven to rotate by a magnetic coupling, or by a bearing seal through which the sample tube guide projects.

Abstract: A high speed temperature controlled, microcircuit electrometer comprising a preamplifier with a very high resistance feedback resistor and temperature sensor on a substrate which is temperature controlled by a thermo-electric module on which the substrate is mounted and which is held within a very small temperature range by temperature control circuitry. The preamplifier, feedback resistor, temperature sensor and thermo-electric module are all enclosed in a hermetically sealed, dry gas environment, maintained at an essentially constant temperature, to reduce the effects of hostile environments, such as temperature changes, vibration, contamination, and humidity. This electrometer operates at high speed and is highly responsive to small current values such as ion currents generated by ionized gas molecules in a mass spectrometer.

Abstract: The various gases in the blood stream are analyzed by a mass spectrometer coupled to the catheter having on its distal end a membrane that passes the gases but not the blood. A "carrier" gas, such as helium, introduced under a small pressure through a small tube within the catheter lumen and into the area behind the membrane will produce a viscous flow that greatly speeds the gases to the mass spectrometer. The carrier gas is extracted prior to its arrival at the mass spectrometer.

Abstract: Developed primarily as a selector for use with a system for analyzing gases from any one of sixteen remote positions, the valve includes a platen containing on one surface sixteen circumferentially aligned input ports and one central output port. Rotatable adjacent the opposite surface of the platen is a selector manifold having a conduit that connects the central output port with any one of the input ports. To rotate the manifold to a new position, a solenoid connected to the rotating shaft on the manifold lifts the manifold from the platen while simultaneously engaging a clutch on a continuously rotating motor shaft. When the selector manifold reaches the desired sample position, identified precisely by the position of a digital encoder disc, the solenoid is released and a spring disengages the motor clutch and forces the selector manifold to seal against the selected port in the platen.