Apparatus for measuring the differential pressure of dissolved gases in a fluid medium

• US 4,366,700 A
• Filed: 06/03/1981
• Issued: 01/04/1983
• Est. Priority Date: 06/03/1981
• Status: Expired due to Fees

• Current Assignee: The United States of America as represented by the Secretary of the Interior
• Original Assignee: The United States of America as represented by the Secretary of the Interior
• Inventors: Bouck, Gerald
• Primary Examiner(s): Kazenske, Edward R.
• Assistant Examiner(s): Carlson, David V.
• Application Number:
  US06/270,040
• Time in Patent Office: 580 Days
• Field of Search: 73/19, 55/158, 55/270
• US Class Current: 73/19.05
• CPC Class Codes: G01N 7/10 by allowing diffusion of components through a porous wall and measuring a pressure or volume difference

Abstract

The disclosed invention, a gasometer, measures the total dissolved gas pressure in a fluid in relation to the ambient atmospheric pressure, thus determining the relative saturation of dissolved gases in the liquid. In prior devices, bubbles have caused inaccurate readings, thus requiring that an operator be present during operation to manually clear bubbles. This gasometer is an improvement over previous devices in that it allows continuous and automatic monitoring of the dissolved gas pressures in the fluid by greatly reducing or eliminating the formation of bubbles in the apparatus. The formation of bubbles is prevented by selectively pressurizing the testing chamber using inlet and outlet valves at either end to selectively vary the pressure. The gasometer containing a pressurized chamber is inserted into the fluid transport system. Located in the interior of the chamber is semipermeable tubing which allows gas to pass through to its interior, but which excludes the fluid. The migrated gas inside the tubing comes to equilibrium with the dissolved gas in the fluid, at which time the relative pressure between the atmosphere outside the tubing and within the system is measured with a device such as a manometer or other pressure measuring device.

Claims

1. An apparatus for measuring dissolved gas pressure in a fluid to determine the level of gas saturation of said fluid, comprising:

a cylindrical container defining a testing chamber for enclosing a semipermeable tubing, said container connected into a fluid communication system;

said semipermeable tubing being hollow for transmission of gases through to the interior of the tubing but prohibiting the passage of the fluid to the tubing interior, the bottom end of said tubing being closed and the top end fastened to a means for communicating the interior of the tubing with a differential pressure gauge outside of the container;

a means for supporting the semipermeable tubing inside the testing chamber in a closely spaced spiral shape;

said differential pressure gauge measuring the pressure difference between the interior of the first tube and the atmosphere;

an inlet and outlet valve connected between each end of said container and the fluid communication system and

said valves selectively pressurizing the testing chamber for inhibiting the formation of bubbles on the semi-permeable tubing inside the chamber.

2. The apparatus of claim 1 wherein the cylindrical container for enclosing a semipermeable tubing comprises:

A cylindrical cap having a means on the bottom outer circumference for connection to a cylindrical sleeve, said cap having a first opening in the upper center portion of said cap for the passage of fluid and for attachment to a fluid outlet means for exit of fluid, and a passage for closely passing the means for communicating between the interior portion of the chamber and said differential pressure gauge for measuring the pressure difference;

said cylindrical sleeve being of sufficient diameter and length to enclose the spiraled semipermeable tubing, the top portion connected to the cylindrical cap and the bottom portion having a means for attachment to a fluid inlet means for entrance of fluid;

said inlet valve having one end connected to the bottom portion of said sleeve and the second end connected to the inflowing portion of a fluid transport assembly, and

said outlet valve having one end connected to the cylindrical cap, the other end connected to the discharge portion of the fluid transport assembly, said inlet and outlet valve regulated to variably pressurize the container.

3. The apparatus of claim 2 wherein the means for supporting the semipermeable tubing comprises:

a plurality of support members, the top ends of which are attached to the underside of the cap, the bottom ends of which are attached to a base plate, the support members mounted so that each is parallel to the other;

said base plate having the support members attached thereto, having an opening therein for passage and mixing of fluid, the bottom closed end of the tubing mounted near the base plate with the tubing closely wrapped in an upward spiral around the plurality of support members, said spiral ending near the cap, with the top end of the tubing connected to the means for communicating between the interior and the differential pressure gauge.

4. The apparatus of claim 2 wherein the means for communicating between the interior and said differential pressure gauge comprises:

a flexible impermeable tube, one end of which is connected to the semipermeable tubing such that the interior portions of each are in communication, and the other end of which is connected to a coupling with a center bore, said coupling mounted in a passage in the cap;

said coupling having a center bore sealably mounted in the passage in the cap, the portion of said coupling on the interior communicating with the impermeable tubing, and the portion on the outside the chamber communicating with the differential pressure gauge.