Anti-vibration support of U-bend flow tubes in a nuclear steam generator

In a heat exchanger having a plurality of spaced-apart tubes and further having at least one support bar disposed intermediately of the respective tubes, the improvement in reducing vibration of the tubes against the support bar, comprising a plurality of pairs of bifurcated legs having respective end portions and being joined together at a common bight portion, the bight portion being secured to the bar, and wherein each end portion resiliently engages a first tube and a second tube respectively, thereby substantially precluding vibration of the tubes.

An apparatus for supporting a flow tube in the U-bend of a bundle of tubes in a heat exchanger, wherein the flow tube has a spring constant K.sub.t and further has a pair of substantially diametrically-opposed sides, and wherein a pair of support bars including a first bar and a second bar is provided, such that the tube is disposed between the first and second bars, comprising a first spring carried by the first bar and resiliently engaging one side of the tube, a second spring carried by the second bar and resiliently engaging the other side of the tube, the springs having a substantially equal spring constant defined as K.sub.s, and the spring constant K.sub.s of the springs being substantially greater than the spring constant of K.sub.t of the tube, such that the tube is supported and substantially prevented from vibrating, and further comprising a plurality of hairpin springs, each hairpin spring having two legs, each leg having a bight, a middle and end portions, wherein the first and second springs carried by the first and second support bars are each a bowed middle portion of a hairpin spring leg, the end portion being secured to the support bar and the bight portion straddles the edge of the support bar.

An apparatus for supporting a flow tube in the U-bend of a bundle of tubes in a heat exchanger, wherein the flow tube has a spring constant K.sub.t and further has a pair of substantially diametrically-opposed sides, and wherein a pair of support bars including a first bar and a second bar is provided, such that the tube is disposed between the first and second bars, comprising a first spring carried by the first bar and resiliently engaging one side of the tube, a second spring carried by the second bar and resiliently engaging the other side of the tube, the springs having a substantially equal spring constant defined as K.sub.s, and the spring constant K.sub.s of the springs being substantially greater than the spring constant of K.sub.t of the tube, such that the tube is supported and substantially prevented from vibrating, and wherein the first and second springs carried by the first and second support bars respectively are each one leg of a pair of bifurcated legs joined together at a common bight, and the bight portion is secured to the respective bar.

The method of assembling a substantially vibration-free support for flow tubes in the U-bend of a heat exchanger comprising the steps of providing a plurality of spaced-apart flow tubes, providing a plurality of support bars, providing springs disposed on and secured to the support bars, providing springs disposed on and secured to the support bars, each spring having a pair of bifurcated legs exerting a resilient force on its respective flow tube which eliminates any clearance gap and substantially precludes vibration, inserting the support bars carrying the springs between columns of tubes, flexing each spring as it encounters each tube before reaching the installed position, and securing the support bar in position once each spring is resiliently engaging the correct flow tube.