Droplet generation method and device
AssigneeThe Technology Partnership PLC
InventorsVictor Carey Humberstone, David Mark Blakey
Life of this patent
Estimating the term…
Abstract
A method of and apparatus for generating liquid droplets from an aperture in a membrane are disclosed in which the aperture has a diameter φ at one face which is at most as large as its diameter at the other face, and a liquid is provided to the one face of the membrane adjacent the aperture. The liquid has a surface tension σ and density ρ. A pressure bias is applied such that the pressure of the liquid at the one face of the membrane is lower than the pressure immediately adjacent to the opposing face of the membrane, and while the bias pressure is applied, the membrane is vibrated at a frequency f which is determined by the relationship: f ≤ ( 5 π σ ρ φ 3 ) 1 / 2 in order to generate droplets emerging from the other face.
Claims13
A method of generating liquid droplets from an aperture in a membrane, the aperture having a diameter φ at one face at most as large as its diameter at the other face, the method comprising:
- providing a liquid to the one face of the membrane adjacent the aperture, the liquid having a surface tension σ and density ρ;
- applying a pressure bias such that the pressure of the liquid at the one face of the membrane is lower than the pressure immediately adjacent to the opposing face of the membrane;
- and
- while the bias pressure is applied, vibrating the membrane at a frequency f which is determined by the relationship:
- f ≤ ( 8 π σ 27 ρ φ 3 ) 1 / 2
- in order to generate droplets emergent from the other face.
A droplet generator for generating droplets of a liquid having a surface tension σ and density ρ, the droplet generator comprising:
- a membrane having a first face and a second face, an aperture extending through the membrane from the first face to the second face, the aperture being of a diameter φ at the first face at most as large as its diameter at the second face;
- means for applying a pressure bias such that the pressure of the liquid at the first face of the membrane is lower than the pressure immediately adjacent to the second face of the membrane;
- and
- a vibration generating means for causing the membrane to vibrate at a frequency f which is determined by the relationship:
- f ≤ ( 8 π σ 27 ρ φ 3 ) 1 / 2
- in order to generate droplets emergent from the other face.
A liquid atomisation head for a droplet generator for generating droplets of a liquid having a surface tension a and density p, the liquid atomisation head comprising:
- a membrane having a first face and a second face, an aperture extending through the membrane from the first face to the second face, the aperture being of a diameter φ at the first face at most as large as its diameter at the second face;
- and
- a vibration generating means for causing the membrane to vibrate at a frequency f which is determined by the relationship:
- f ≤ ( 8 π σ 27 ρ φ 3 ) 1 / 2
- in order to generate droplets emergent from the other face.
Dependencies are inferred from the claim text.