US 5,969,736 AGranted

Passive pressure regulator for setting the pressure of a liquid to a predetermined pressure differential below a reference pressure

AssigneeHewlett-Packard Company

InventorsLeslie A. Field, Phillip Barth, David J. Waller, George D. Zuras, Jr., Paul P. Merchant, Storrs Hoen, Channing R. Robertson

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Abstract

A pressure regulator that sets the pressure of a liquid to a predetermined pressure differential below a reference pressure, such as atmospheric pressure. The pressure regulator comprises a liquid delivery channel and a capillary array. The liquid delivery channel includes a liquid input and a liquid output. The liquid flows through the liquid delivery channel from the liquid input to the liquid output. The capillary array is composed of ones of an elongate capillary. The capillary includes a first end in fluid communication with the liquid delivery channel and a second end in pressure communication with a source of the reference pressure. The liquid flows through the first end into the capillary to form a liquid surface in the capillary. The second end is remote from the first end. The capillary has cross-sectional dimensions in relation to the surface tension of the liquid and the angle of contact between the liquid and the capillary such that the pressure drop across the liquid surface in the capillary is equal to the predetermined pressure differential.

Claims31

Dependent claims

A pressure regulator for setting the pressure of a liquid to a predetermined pressure differential below a reference pressure, the liquid having a surface tension, the pressure regulator comprising:

a liquid inlet;
a liquid outlet;
a liquid delivery channel through which the liquid flows from the liquid inlet to the liquid outlet;
and
a capillary array composed of substantially similar ones of an elongate capillary, the capillary being bounded by a wall, having a length and having cross-sectional dimensions in a plane substantially perpendicular to the length, the capillary including:
in fluid communication with the liquid delivery channel, a first end through which the liquid flows into the capillary to form a liquid surface therein, and
in pressure communication with the reference pressure, a second end remote from the first end,
the cross-sectional dimensions of the capillary, the surface tension of the liquid in the capillary and a contact angle between the liquid and the wall of the capillary collectively establishing a pressure drop across the liquid surface in the capillary that defines the predetermined pressure differential below the reference pressure.

5 more elements

Dependencies are inferred from the claim text.