Method and apparatus for measuring porosity using a surface-temperature porosimeter
AssigneeGeneral Dynamics Corporation
InventorThomas J. De Lacy
Life of this patent
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Abstract
A method and apparatus for measuring the porosity or density of a porous structure surface is disclosed. A controlled quantity of volatile liquid is applied to a porous surface and is allowed to evaporate. The temperature at the surface reaches equilibrium at the point necessary to supply the latent heat of vaporization of the liquid. This equilibrium temperature depends on the evaporation rate, which has been found to be a function of surface porosity. The porosimeter substantially eliminates other factors influencing evaporation rate, and measures and records the temperature at the surface. Once calibrated with samples of known porosity, this system is capable of making rapid, accurate surface porosity measurements.
Claims6
A porosimeter comprising:
- means to supply a selected quantity of volatile liquid to a point on a porous structure surface;
- a chamber in contact with said surface surrounding said point to maintain the space adjacent to said point within said chamber at a substantially constant temperature;
- temperature measuring means in contact with said surface at said point;
- and
- recording means for recording temperature over a time period after said liquid is applied at said point.
The method of measuring the surface porosity of a structure which comprises:
- applying a selected quantity of a volatile liquid to a point on a porous structure surface;
- maintaining the space adjacent to said surface near said point at a substantially constant temperature;
- continuously measuring the temperature of said surface at said point;
- continuously recording the temperature over a time period after said liquid is applied to said surface.
Dependencies are inferred from the claim text.