An improved total dissolved gas pressure collector has a high ratio of surface area to internal volume and is configured in a compact unit which still permits good fluid flow across it. The module forms part of an improved gas sensor package having high sensitivity (e.g., less than 0.1 mm Hg, preferably less than 0.05 mm Hg) and rapid response times (e.g., less than 5 minutes to 99% of equilibrium, preferably less than 2 minutes to this value). The module comprises: a base having an opening therein; a resilient fitting in said opening in the base; a plurality of upstanding capillary tube supports; an elongated, gas-permeable capillary tube having defined internal volume and defined external surface area, the tube being closed at one end which is secured to one of the supports and having one end adapted to communicate with a total gas pressure transducer through the resilient fitting. Also provided are an acquisition and analysis system including the module, and a method for making the improved module. The devices of the invention are particularly suitable for measuring total dissolved gas pressure in a submarine environment.

Total dissolved gas pressure sensor, replaceable collector module and process

A calibration vial is described for storing and calibrating under sterile conditions a blood gas sensor that comprises an optical fiber whose sensing end carries a sensing element, such as a chromophore or fluorophore. The vial contains a calibrating liquid and, in its preferred embodiment, is structured to keep the end of the filter wet and permit fast calibration of the sensor without spillage of the calibrating liquid. The vial has a tubular inner calibration chamber in which the end of the fiber resides and which has a sterile filter-plugged gas inlet in its bottom and an outer concentric calibrating liquid reservoir chamber. The bottoms of the two chambers are interconnected by one or more liquid reflux ports that are positioned such that the gas coming into the bottom of the calibration chamber aspirates liquid from the reservoir chamber into the calibration chamber. This permits rapid mixing and circulation of the liquid upwardly through the calibration chamber. The upper ends of the chambers are interconnected by a passageway through which liquid is returned to the reservoir and spent gas exits the calibration chamber. The spent gas is vented to the atmosphere via a vent that opens into the top of the reservoir chamber above the liquid level therein.

Apparatus for calibrating a sensor for detecting the presence of a gas in a liquid

A method and apparatus for indirectly measuring the percentage of dissolved gas in a process liquid by injecting bubbles of the same kind of gas of predetermined diameter into the liquid to be measured and then measuring gas bubble life or survival time. Bubble lifetime is directly related to dissolved gas percentage. A relatively long gas bubble lifetime would be indicative of a highly saturated or poorly degassed process liquid, whereas a relatively short bubble lifetime would be indicative of a low degree of saturation or a well degassed process liquid. In one embodiment, dissolved gas percentage is determined by placing a small quantity of the process liquid into a container, injecting a burst of gas bubbles, of predetermined size, into this quantity of liquid, and then measuring gas bubble lifetime. In another embodiment, a portion of the liquid being measured is continuously routed through a tube at a known constant flow rate. A continuous series of individual bubbles are then injected into the transparent tube, at a fairly constant rate, at or near the bottom thereof. The maximum distance attained by a bubble within the transparent tube before disappearing from view is a direct indication of the percentage of dissolved gas in the liquid being measured.

Bubble injection dissolved gas measurement method and apparatus

A probe is disclosed for use with a dissolved gas meter, which is capable of measuring the concentration of dissolved gas in a fluid by measuring the permeation of gas through a membrane into an electrolyte solution. The probe includes an inner member, preferably tubular, disposed inside an outer member, preferably tubular, each tubular member having an open top end. Preferably, the inner tubular member and the outer tubular member are coaxially located such that an annular space is formed between the inner and outer tubular member. The probe further includes a plurality of electrodes operably connected inside the probe to the meter. A counter electrode extends into the central chamber of the inner tubular member, along the central axis. A working electrode is wrapped around the outer tubular member. A reference electrode is wrapped around the inner tubular member. A membrane, preferably made of silicone elastomer material, covers at least a portion of the outer tubular member and encloses the working electrode so as to form a pocket around a portion of the working electrode. Electrolyte solution is injected into the top of the inner tubular member and flows from a central chamber in the inner tubular member to the outside of the outer tubular member and around the working electrode through a series of holes, which create passages for the flow of the solution. As such, the electrodes are in at least in partial fluid communication with the electrolyte solution.

Probe having coaxial design for use with dissolved oxygen meter

Beer fermentation apparatus comprises a main pipe for transporting a water-entrained mixture of wort, yeast and gas to a fermentation tank. A measuring device is mounted in a by-pass circuit of the main pipe for measuring the amount of gas dissolved in the water, the device comprising a vertically disposed measuring chamber having an inlet at its lower end and an outlet at its upper end which are connected to upstream and downstream portions of the main pipe for flowing the mixture through the measuring chamber. The chamber inlet is located a sufficient distance above the lowermost end of the chamber so as to effect formation of a relatively stagnant flow region which is substantially free of gas bubbles in the measuring chamber beneath the level of the inlet during flow of the water-entrained mixture through the measuring chamber. A gas-sensitive element extends downwardly in the measuring chamber into the stagnant flow region for measuring the amount of gas dissolved in the mixture and due to the relative locations of the chamber inlet and outlet and the location of the gas-sensitive element, the gas bubbles and lighter mixture particles entrained in the water flow in the inlet upwardly through the measuring chamber and out the outlet while the heavier mixture particles entrained in the water tend to flow downwardly and settle in the stagnant flow region thereby minimizing erroneous measurements which would otherwise occur due to the presence of gas bubbles in the vicinity of the gas-sensitive element.

Device for measuring the amount of gas dissolved in a liquid

Apparatus for measuring the dissolved oxygen content of water comprises an open-ended duct immersed in the water in an upright position, an oxygen-detecting probe in the lower end portion of the duct, and means for injecting a continuous stream of air into the upper portion of the duct, the air causing water to rise in the duct and thereby induce a flow of water into the duct and past the probe. A valve in the upper end of the duct is operable by compressed air to shut off the top of the duct so that air builds up inside the duct and back-flushes the liquid through a strainer on the lower end of the duct. Displacement of the water around the duct by air enables the probe to be calibrated. The upper section of the duct into which air is injected may be connected to the lower section containing the probe by polyethylene tubing of a length to enable the lower section of the duct to be lowered to any desired depth.

Charles Alfred Morrison

Papers

Method and apparatus for testing properties of liquids