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A porosimeter includes a pressurizable sample chamber with a membrane located directly below the sample. The membrane pores have a smaller size than any of the sample pores of interest. A fluid reservoir is located below the membrane such that the reservoir and the membrane form a seal. In operation

A porosimeter includes a pressurizable sample chamber with a membrane located directly below the sample. The membrane pores have a smaller size than any of the sample pores of interest. A fluid reservoir is located below the membrane such that the reservoir and the membrane form a seal. In operation, as fluid enters the fluid reservoir through the membrane or a reservoir inlet, fluid already in the fluid reservoir is displaced through a reservoir exit. An inlet in a fluid displacement reservoir receives the fluid displaced from the fluid reservoir. A recirculation line receives fluid from the exit of the fluid displacement reservoir and circulates the fluid into the inlet of the fluid reservoir. In a preferred embodiment, a pump recirculates the fluid through the recirculation line. Fluid returned to the reservoir circulates over the bottom of the membrane, and sweeps air bubbles out of the reservoir.

대표청구항 ▼

1. A method of evaluating the porosity characteristics of a sample of material having a plurality of pores using a porosimeter comprising a pressurizable sample chamber for holding the sample, a membrane located at a bottom of the sample chamber and having a plurality of pores, wherein the membrane

1. A method of evaluating the porosity characteristics of a sample of material having a plurality of pores using a porosimeter comprising a pressurizable sample chamber for holding the sample, a membrane located at a bottom of the sample chamber and having a plurality of pores, wherein the membrane pores have a size smaller than any of the sample pores of interest, a fluid reservoir located below the membrane, and a fluid displacement reservoir, comprising the steps of:a) placing the sample in the sample chamber, on the membrane;b) wetting the sample with a fluid until the fluid has entered substantially all of the pores in the sample and the membrane;c) applying a pressure in the sample chamber which is greater than a bubble point pressure of the sample, but less than a bubble point pressure of the membrane, such that as fluid enters the fluid reservoir through the membrane, it displaces fluid already in the fluid reservoir into the fluid displacement reservoir;d) pumping the displaced fluid back into the fluid reservoir along a bottom of the membrane such that air bubbles stuck to the membrane are swept away from the membrane; ande) measuring a weight change in the fluid displacement reservoir after a weight in the fluid displacement reservoir reaches an equilibrium. 2. The method of claim 1, wherein the fluid is a fluid with high air diffusivity. 3. The method of claim 2, wherein the fluid is water. 4. The method of claim 1, further comprising the step of calculating a pore volume of the sample using the fluid weight change measured in step (e). 5. The method of claim 1, wherein the pump is a peristaltic pump. 6. The method of claim 1 in which the step of wetting the sample further comprises applying pressure at greater than the bubble point of the sample to force fluid into the pores of the sample. 7. An improved method of evaluating the porosity characteristics of a sample of material having a plurality of pores, using a porosimeter comprising a pressurizable sample chamber for holding the sample, a membrane located at a bottom of the sample chamber and having a plurality of pores, wherein the membrane pores have a size smaller than any of the sample pores of interest, a fluid reservoir located below the membrane, and a fluid displacement reservoir, wherein a wetted sample is subjected to a pressure in the sample chamber which is greater than a bubble point pressure of the sample, but less than a bubble point pressure of the membrane, such that as fluid enters the fluid reservoir through the membrane, it displaces fluid already in the fluid reservoir into the fluid displacement reservoir, wherein the improvement comprises:recirculating the displaced fluid through the fluid reservoir along the membrane such that air bubbles stuck to the membrane are swept away from the membrane. 8. The method of claim 7, wherein the fluid is a fluid with high air diffusivity. 9. The method of claim 8, wherein the fluid is water. 10. The method of claim 7, further comprising the step of calculating a pore volume of the sample using the fluid weight change in the fluid displacement reservoir. 11. The method of claim 7, wherein the pump is a peristaltic pump. 12. A porosimeter for evaluating the porosity characteristics of a sample of material having a plurality of pores comprising:a) a pressurizable sample chamber for holding the sample, comprising a membrane located at a bottom of the sample chamber and having a plurality of pores, wherein the membrane pores have a size smaller than any of the sample pores;b) a fluid reservoir located below the membrane, comprising an inlet and an exit for fluid, such that as fluid enters the fluid reservoir through the membrane or the inlet, it displaces fluid already in the fluid reservoir through the exit;c) a fluid displacement reservoir comprising an inlet and an exit, wherein the inlet receives the fluid displaced from the fluid reservoir; andd) a recirculation line that receives fluid from the exit of the fluid displacement reservoir and circulates the fluid through the inlet of the fluid reservoir and along the membrane such that air bubbles stuck to the membrane are swept away from the membrane. 13. The porosimeter of claim 12, further comprising a balance for measuring weight change of the fluid displacement reservoir continuously as the fluid moves continuously through the displacement reservoir. 14. The porosimeter of claim 12, further comprising a fluid having high air diffusivity. 15. The porosimeter of claim 14, wherein the fluid is water. 16. The porosimeter of claim 12, wherein the porosity characteristic being evaluated is the pore volume of the sample. 17. The porosimeter of claim 12, further comprising a pump connected to the recirculation line, wherein the pump aids in circulation of the fluid. 18. The porosimeter of claim 17, wherein the pump is a peristaltic pump. 19. An improved porosimeter for evaluating the porosity characteristics of a sample of material having a plurality of pores of the type comprising a pressurizable sample chamber for holding the sample, a membrane located at a bottom of the sample chamber and having a plurality of pores, wherein the membrane pores have a size smaller than any of the sample pores of interest, wherein the improvement comprises:a) a fluid reservoir located below the membrane, comprising an inlet and an exit for fluid, such that as fluid enters the fluid reservoir through the membrane or the inlet, it displaces fluid already in the fluid reservoir;b) a fluid displacement reservoir comprising an inlet and an exit, wherein the inlet receives the fluid displaced from the fluid reservoir; andc) a recirculation line that receives fluid from the exit of the fluid displacement reservoir and circulates the fluid through the inlet of the fluid reservoir and along the membrane such that air bubbles stuck to the membrane are swept away from the membrane. 20. The porosimeter of claim 19, further comprising a balance for measuring weight change of the fluid displacement reservoir after a weight in the fluid displacement reservoir reaches an equilibrium. 21. The porosimeter of claim 19, further comprising a fluid having high air diffusivity. 22. The porosimeter of claim 21, wherein the fluid is water. 23. The porosimeter of claim 19, wherein the porosity characteristic being evaluated is the pore volume of the sample. 24. The porosimeter of claim 19, further comprising a pump connected to the recirculation line, wherein the pump aids in circulation of the fluid. 25. The porosimeter of claim 24, wherein the pump is a peristaltic pump.