Abstract: A variable orifice device for passing fluent material under pressure includes a piece of resilient material bent out of its normal shape so that one surface is in tensile stressed condition and the other surface is in compressive stressed condition. A slit extends between the two surfaces. Because of the difference in the stressed conditions of the two surfaces, one end of the slit is open and the other end, at the compressively stressed surface, is in forced closed condition. The piece of resilient material is mounted in its bent, stressed condition in a frame which holds the material in the bent condition. The piece of resilient material may be cut from silicone rubber tubing such as is used for peristaltic pumps. The frame may be two annular members, one of which is a push fit in the other, with the other having an annular shoulder against which a disc of the resilient material is trapped and sealed by the one annular member.

Abstract: A variable orifice device for passing fluent material under pressure includes a piece of resilient material bent out of its normal shape so that one surface is in tensile stressed condition and the other surface is in compressive stressed condition. A slit extends between the two surfaces. Because of the difference in the stressed conditions of the two surfaces, one end of the slit is open and the other end, at the compressively stressed surface, is in force closed condition. The piece of resilient material is mounted in its bent, stressed condition in a frame which holds the material in the bent condition. The piece of resilient material may be cut from silicone rubber tubing such as is used for peristaltic pumps. The frame may be two annular members, one of which is a push fit in the other, with the other having an annular shoulder against which a disc of the resilient material is trapped and sealed by the one annular member.