GB1585373A

GB1585373A - Method and device for scarfing a workpiece surface to remove defects

Info

Publication number: GB1585373A
Application number: GB3021877A
Authority: GB
Original assignee: Centro Maskin I Goteborg AB
Current assignee: Centro Maskin I Goteborg AB
Priority date: 1976-07-19
Filing date: 1977-07-19
Publication date: 1981-03-04
Also published as: SE7608210L; JPS5311863A; JPS5625905B2; DE2731864A1; SE407353B; FR2358955A1

Description

(54) METHOD AND DEVICE FOR SCARFING A WORKPIECE SURFACE TO REMOVE DEFECTS (71) We, CENTRO-MASKIN GOTEBORG AB, a Swedish joint-stock company, of Fack, S402 56 Göteborg 47, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of and a device for scarfing a workpiece surface.

In scarfing, oxygen gas of high purity is used almost exclusively as oxidising medium. Heretofore the oxygen gas was considered to have to flow out from a scarfing device in a laminar way.

The laminar gas flow can give rise to elevated portions of ridge shape in the worked zone.

Such ridge-shaped portions are undesirable and require subsequent working by grinding or the like.

The laminar gas flow over the workpiece surface being worked does not permit an effective contact or exchange between the workpiece and the oxidising gas molecules, because the laminar flow is divided into several layers with different flow rates, of which layers the one closest to the workpiece surface has the lowest rate.

According to the invention, there is provided a method of scarfing a workpiece surface, wherein turbulence is imparted to the whole of a flow of oxidising gas, and the turbulent gas is discharged from the exit end of a scarfing device onto the workpiece surface.

The invention also provides a scarfing device comprising an inlet for oxidising gas, a gas passage through the device, a vortex generator in the passage for imparting turbulence to the whole of the gas, and an outlet for the turbulent gas.

The invention also provides an alternative form of scarfing device, comprising an inlet for oxidising gas, a gas passage through the device and an outlet for the gas, the surfaces of the gas passage being formed so as to impart turbulence to the whole of the oxidising gas flowing through.

Owing to the fact that the gas is caused to flow with turbulence, the formation of ridges on the workpiece surface is prevented.

The invention is described in the following, by way of example, with reference to the accompanying drawing, in which Figure 1 is a lateral view of a scarfing device intended for turbulent gas flow, and Figure 2 is a view from above of the device according to Figure 1.

The scarfing device 1 is preferably hingedly supported and adjustable in height. An eccentrically mounted bar 17 can distribute the gas from several gas hoses 11-16 into a gas passage 3 in the scarfing device 1.

Within the passage 3 a vortex generator 2 is located which, in the embodiment shown, is formed with balls arranged in rows laterally offset relative to each other. The gas, after passing through the vortex generator 2, flows down the passage 3 with a turbulent flow.

The embodiment shown comprises only one scarfing device. It is, however, possible to arrange several devices to the side of each other, possibly offset in the longitudinal direction, so that an entire workpiece surface can be worked during one feed process.

The method described can be utilized with most known scarfing devices. It may, however, be necessary to increase the pressure of the working gas, because a certain pressure drop takes place over the vortex generator, and at the same time the feed rate between workpiece and scarfing device should be increased for a given working depth, because the higher efficiency of the exchange between gas and workpiece molecules increased the working capacity substantially.

The device described produces a worked area without ridge-shaped portions and ensures exchange between oxidising oxygen molecules and the workpiece surface.

The scarfing device is especially suitable for spot scarfing a workpiece surface and permits very efficient and troublefree scarfing.

WHAT WE CLAIM IS: 1. A method of scarfing a workpiece surface, wherein turbulence is imparted to the whole of a flow of oxidising gas, and the turbulent gas is discharged from the exit end of a scarfing device onto the workpiece surface.

2. A scarfing device comprising an inlet for oxidising gas, a gas passage through the device, a vortex generator in the passage for imparting turbulence to the whole of the gas, and an outlet for the turbulent gas.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) METHOD AND DEVICE FOR SCARFING A WORKPIECE SURFACE TO REMOVE DEFECTS (71) We, CENTRO-MASKIN GOTEBORG AB, a Swedish joint-stock company, of Fack, S402 56 Göteborg 47, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of and a device for scarfing a workpiece surface. In scarfing, oxygen gas of high purity is used almost exclusively as oxidising medium. Heretofore the oxygen gas was considered to have to flow out from a scarfing device in a laminar way. The laminar gas flow can give rise to elevated portions of ridge shape in the worked zone. Such ridge-shaped portions are undesirable and require subsequent working by grinding or the like. The laminar gas flow over the workpiece surface being worked does not permit an effective contact or exchange between the workpiece and the oxidising gas molecules, because the laminar flow is divided into several layers with different flow rates, of which layers the one closest to the workpiece surface has the lowest rate. According to the invention, there is provided a method of scarfing a workpiece surface, wherein turbulence is imparted to the whole of a flow of oxidising gas, and the turbulent gas is discharged from the exit end of a scarfing device onto the workpiece surface. The invention also provides a scarfing device comprising an inlet for oxidising gas, a gas passage through the device, a vortex generator in the passage for imparting turbulence to the whole of the gas, and an outlet for the turbulent gas. The invention also provides an alternative form of scarfing device, comprising an inlet for oxidising gas, a gas passage through the device and an outlet for the gas, the surfaces of the gas passage being formed so as to impart turbulence to the whole of the oxidising gas flowing through. Owing to the fact that the gas is caused to flow with turbulence, the formation of ridges on the workpiece surface is prevented. The invention is described in the following, by way of example, with reference to the accompanying drawing, in which Figure 1 is a lateral view of a scarfing device intended for turbulent gas flow, and Figure 2 is a view from above of the device according to Figure 1. The scarfing device 1 is preferably hingedly supported and adjustable in height. An eccentrically mounted bar 17 can distribute the gas from several gas hoses 11-16 into a gas passage 3 in the scarfing device 1. Within the passage 3 a vortex generator 2 is located which, in the embodiment shown, is formed with balls arranged in rows laterally offset relative to each other. The gas, after passing through the vortex generator 2, flows down the passage 3 with a turbulent flow. The embodiment shown comprises only one scarfing device. It is, however, possible to arrange several devices to the side of each other, possibly offset in the longitudinal direction, so that an entire workpiece surface can be worked during one feed process. The method described can be utilized with most known scarfing devices. It may, however, be necessary to increase the pressure of the working gas, because a certain pressure drop takes place over the vortex generator, and at the same time the feed rate between workpiece and scarfing device should be increased for a given working depth, because the higher efficiency of the exchange between gas and workpiece molecules increased the working capacity substantially. The device described produces a worked area without ridge-shaped portions and ensures exchange between oxidising oxygen molecules and the workpiece surface. The scarfing device is especially suitable for spot scarfing a workpiece surface and permits very efficient and troublefree scarfing. WHAT WE CLAIM IS:

1. A method of scarfing a workpiece surface, wherein turbulence is imparted to the whole of a flow of oxidising gas, and the turbulent gas is discharged from the exit end of a scarfing device onto the workpiece surface.

3. A scarfing device, comprising an inlet for oxidising gas, a gas passage through the device and an outlet for the gas, the surfaces of the gas passage being formed so as to impart turbulence to the whole of the oxidising gas flowing through.

4. A method of scarfing a workpiece surface, substantially as herein described with reference to the accompanying drawings.

5. A scarfing device substantially as herein described with reference to the accompanying drawings.