GB2157993A - An improved apparatus for impressing pads on tubular bodies - Google Patents

Abstract

The apparatus comprises a bolster 1 slidable within a tubular body 10 and having a cross-sectional configuration conforming to that of the tubular body. The bolster carries a fluid-actuated former which is urged outwardly against a localised region of the tubular body to impress into a die-recess 13 an external pad on the body. Additional fluid-actuated means may operate in directions perpendicular to that of the former to support the body. <IMAGE>

Description

SPECIFICATION An improved apparatus for impressing pads on tubular bodies The present invention concerns apparatus for impressing pads on the exterior of tubular bodies. In particular, the invention concerns apparatus for impressing spacer pads on the exterior of nuclear fuel wrappers.

Wrappers are used for the containment of nuclear fuel in certain reactors comprise elongate tubular bodies of hexagonal cross-section. The wrappers containing fuel are stacked together and it is required to provide spacing between the wrappers. Such spacers can be provided by impressing pads on the surfaces of the wrappers. To avoid movement and vibration of the assembled wrappers it is necessary to impress pads accurately and uniformly.

According to the present invention apparatus for impressing pads on the exterior of tubular bodies comprises a bolster slidable within a tubular body and having a cross-section configuration conforming to that of the hollow body, at least one fluidactuated former on the bolster operable to engage and deform a localised region of the body outwardly to impress an external pad on the body and clamp means for fixedly securing the body during the formation of the pad.

Preferably, the bolster carries additional fluid-actuated means operable in a direction normal to the direction of operation of the former, the additional fluid-actuated means serving to maintain the hexagonal configuration of the body during impression of the pad.

The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a diagrammatic sectional view of a bolster, Figure 2 is an elevation of the bolster in the direction of the Arrow A in Figure 1, Figure 3 shows the bolster positioned within a nuclear fuel wrapper.

With reference to Figures 1 and 2, a bolster 1 comprises a solid metal block of hexagonal section. A slot 2 extending centrally of the upper face of the block communicates through cylinders 3 with a gallery 4 for a pressure fluid. An external pressure fluid line can be coupled to the gallery 4 by means of a threaded coupling 5 in an end face of the block. A former is located in the slot 2 and normally does not extend beyond the upper face of the block. The application of pressure fluid to the gallery 4 and the cylinder 3 displaces the former outwardly beyond the face of the block.

In a similar manner, slots 6 at the opposing central apices of the block communicate through cylinders 7 and pressure fluid galleries 8 with a further threaded coupling 9 in the end face for a pressure fluid line. The slots 6 accomodate clamp members which are extended beyond the apices on application of pressure fluid.

Figure 3 shows the block mounted within an hexagonal wrapper 10 for nuclear fuel. The wrapper 10 is supported on a platen 11 and its upper surface is engaged by a die block 12 having a recess 13 conforming to the profile of the former in the bolster. The wrapper 10 is securely clamped between the platen and the die block and pressure fluid is applied to the bolster to extend the former and the clamps. The clamps operating outwardly at the opposite apices of the wrapper and in a plane normal to that of the former maintain the wrapper against inward deformation on the application of pressure exerted by the former to the upper face of the wrapper. The former creates a pad or protruberance on the exterior of the upper face.

The shape and dimensions of the pad are determined by the shape and dimensions of the former.

As a result the pad is formed to close and reproducable tolerances.

In the above embodiment a pad is formed on one face only of the wrapper. By appropriate modification it is possible to provide a bolster capable of forming pads simultaneously on two or more faces of the wrapper.

1. Apparatus for impressing pads on the exterior of tubular bodies comprising a bolster slidable within a tubular body and having cross-sectional configuration conforming to that of the tubular body, a fluid-actuated former on the bolster operable to engage and deform a localised region of the body outwardly to impress an external pad on the body and clamp means for fixedly securing the body during the formation of the pad.

2. Apparatus as claimed in Claim 1 including additional fluid-actuated means operable in a direction normal to the direction of operation of the former to maintain the configuration of the tubular body during impression of the pad.

3. Apparatus for impressing pads on the exterior of tubular bodies constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An improved apparatus for impressing pads on tubular bodies The present invention concerns apparatus for impressing pads on the exterior of tubular bodies. In particular, the invention concerns apparatus for impressing spacer pads on the exterior of nuclear fuel wrappers. Wrappers are used for the containment of nuclear fuel in certain reactors comprise elongate tubular bodies of hexagonal cross-section. The wrappers containing fuel are stacked together and it is required to provide spacing between the wrappers. Such spacers can be provided by impressing pads on the surfaces of the wrappers. To avoid movement and vibration of the assembled wrappers it is necessary to impress pads accurately and uniformly. According to the present invention apparatus for impressing pads on the exterior of tubular bodies comprises a bolster slidable within a tubular body and having a cross-section configuration conforming to that of the hollow body, at least one fluidactuated former on the bolster operable to engage and deform a localised region of the body outwardly to impress an external pad on the body and clamp means for fixedly securing the body during the formation of the pad. Preferably, the bolster carries additional fluid-actuated means operable in a direction normal to the direction of operation of the former, the additional fluid-actuated means serving to maintain the hexagonal configuration of the body during impression of the pad. The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a diagrammatic sectional view of a bolster, Figure 2 is an elevation of the bolster in the direction of the Arrow A in Figure 1, Figure 3 shows the bolster positioned within a nuclear fuel wrapper. With reference to Figures 1 and 2, a bolster 1 comprises a solid metal block of hexagonal section. A slot 2 extending centrally of the upper face of the block communicates through cylinders 3 with a gallery 4 for a pressure fluid. An external pressure fluid line can be coupled to the gallery 4 by means of a threaded coupling 5 in an end face of the block. A former is located in the slot 2 and normally does not extend beyond the upper face of the block. The application of pressure fluid to the gallery 4 and the cylinder 3 displaces the former outwardly beyond the face of the block. In a similar manner, slots 6 at the opposing central apices of the block communicate through cylinders 7 and pressure fluid galleries 8 with a further threaded coupling 9 in the end face for a pressure fluid line. The slots 6 accomodate clamp members which are extended beyond the apices on application of pressure fluid. Figure 3 shows the block mounted within an hexagonal wrapper 10 for nuclear fuel. The wrapper 10 is supported on a platen 11 and its upper surface is engaged by a die block 12 having a recess 13 conforming to the profile of the former in the bolster. The wrapper 10 is securely clamped between the platen and the die block and pressure fluid is applied to the bolster to extend the former and the clamps. The clamps operating outwardly at the opposite apices of the wrapper and in a plane normal to that of the former maintain the wrapper against inward deformation on the application of pressure exerted by the former to the upper face of the wrapper. The former creates a pad or protruberance on the exterior of the upper face. The shape and dimensions of the pad are determined by the shape and dimensions of the former. As a result the pad is formed to close and reproducable tolerances. In the above embodiment a pad is formed on one face only of the wrapper. By appropriate modification it is possible to provide a bolster capable of forming pads simultaneously on two or more faces of the wrapper. CLAIMS

1. Apparatus for impressing pads on the exterior of tubular bodies comprising a bolster slidable within a tubular body and having cross-sectional configuration conforming to that of the tubular body, a fluid-actuated former on the bolster operable to engage and deform a localised region of the body outwardly to impress an external pad on the body and clamp means for fixedly securing the body during the formation of the pad.

2. Apparatus as claimed in Claim 1 including additional fluid-actuated means operable in a direction normal to the direction of operation of the former to maintain the configuration of the tubular body during impression of the pad.

3. Apparatus for impressing pads on the exterior of tubular bodies constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.