GB2024872A - Apparatus for gas carburizing a bore - Google Patents

Abstract

Gas feeding means 3 and gas discharging means 5 are cantilevered on corresponding brackets 1 and 2 of a frame. The object 4 whose bore is to be carburized is clamped between the means 3 and 5, which are moved towards each other by pneumatic piston- and-cylinder devices. The means 3 and 5 and the object 4 are rotated by drives 9. A carriage 26 carrying heaters 24, 25 and a cooling sprayer 29 moves along the object 4 and supports it on rollers 28. The apparatus is used for gas carburizing the bores of pipes for conveying abrasive material. <IMAGE>

Description

SPECIFICATION Apparatus for gas carburizing a bore The present invention relates to apparatus for gas carburizing of a bore in object, e.g. for strengthening the bore of a pipe serving to handle abrasive material, e.g. pulp, or used for the pneumatic conveying of bulk materials.

With the hydraulic and pneumatic conveying of abrasive materials by pipelines coming into vogue, there is an ever increasing demand for pipes with high-strength bores. All the known equipment fails to meet this demand and, as a result, difficulties are experienced in operating pipelines for the pneumatic or hydraulic conveying of pulp and other abrasive materials.

What is desired is apparatus for gas carburizing the bore in an object which will improve the quality of the surface treated, assuring the formation of a carburized case of uniform depth at any point of the bore. It is equally desirable to automate the feeding of carburizing gas into the sealed off bore of the object while it is rotated.

Long objects should be prevented from bending under their own weight in the course of their treatment.

The present invention provides apparatus for the gas carburizing of the bore in an object incorporating a means of feeding gas into the bore of the treated object and a means of discharging gas from the bore of this object which are secured as cantilevers to corresponding brackets of a frame and are provided with drives causing them to displace longitudinally so as to clamp the treated object at the opposite end faces, said apparatus also incorporating a drive causing the treated object to rotate integrally with the means of feeding gas into the bore as well as with the means of discharging gas from the bore of the treated object and incorporating a manifold which communicates with a gas line of the means of feeding gas into the bore of the treated object whereas contrivances for heating and cooling are mounted on a table which is provided with a drive for longitudinal travel and is installed on horizontal guides.

Continuous rotation of the object, while the heating and cooling means are moved-along the bore, is instrumental in achieving a carburized case of uniform depth. The feeding of carburizing gas into the bore of the rotating object can be a completely automatic operation.

It is expedient for the means for feeding and discharging gas to be provided with spaces for a coolant to pass therethrough and to accommodate gas lines therein. This extends the service life of the means for feeding gas and the means for discharging gas.

It is also expedient to accommodate rollers on the carriage so as to give thereby support to the object. This will prevent the bending of the object during its heating up and eliminate residual deformation.

The apparatus allows automatic feeding of gas into the sealed off bore of the object while this object is being rotated. In addition, the apparatus can be used to extend the service life of the pipes used for conveying abrasive materials in either liquid or gaseous medium in huge amounts under the conditions of high velocities. An extension of the service life of pipelines is conductive to savings in the cost of conveying abrasive materials.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a gas-carburizing apparatus in its initial position; Figure 2 is a view similar to Figure 1, illustrating the apparatus in a position following the treatment of an object; Figure 3 is a plan view corresponding to Figure 1; Figure 4 is a sectional elevation of the means for feeding gas into the bore of the treated object, together with the mechanism imparting rotary motion thereto; and Figure 5 schematically illustrates the way carburizing gas is fed into the bore and discharged therefrom.

The illustrated apparatus for gas carburizing a bore in an object is installed on a frame having brackets 1 and 2 (Figures 1, 2 and 3). Mounted on the bracket 1 is a cantilevered means 3 for feeding gas into the bore of the object 4 shown by dot and dash lines. A cantilevered means 5 for discharging gas from the bore of the object 4 is arranged coaxially with the feeding means 3 and is mounted on the bracket 2. Each of the means 3 and 5 is provided with a drive 6 (Figure 4) enabling it to move longitudinally, the drive being, for example, a double-acting pneumatic pistonand-cylinder device whose chambers are connected to respective air passages 7 and 8 provided in the bracket.Both drives 6 are of identical construction, functioning so as to clear a space for the object 4 by moving the means 3 and 5 in the outward direction (i.e. away from each other) and then clamping the object 4 between the means 3 and 5 by displacing them inwardly until they abut against the object at the ends of the bore.

Rotary drives 9 for causing the object 4 to rotate by rotating the feeding means 3 and the discharging means 5 (which abut against the object) are mounted on the respective brackets 1 and 2. Alternatively, a single rotary drive 9 mounted on either the bracket 1 or the bracket 2 may be sufficient to rotate the object 4. Each rotary drive 9 is a d-c motor 10 (Figure 4) coupled to corresponding feeding or discharging means through the intermediary of gears 11, drive pins 12, and thrust flanges 1 3. The means 3 and 5 are located inside corresponding piston rods 14 of the drives (Figure 4) inducing longitudinal displacement.

The feeding means 3 is provided with a gas line 20 supplied by a manifold 1 5 communicating through a pipe 1 6 with supply pipes 1 7 and 1 8 via a slide valve 19 for the automatic initiating and stopping of the gas flow.

The means 3 for feeding gas and the means 5 for discharging waste gas are provided with cooling arrangements. To this end a coolant (water) is admitted through pipelines 21 communicating through manifolds 22 with a cooling spaces in the feeding means 3 being cooled, whereas the gas line 20 is mounted coaxially in the cooling space. A similar arrangement is provided for the discharging means 5.

The apparatus is provided with a contrivance 23 (Figure 1) for heating the object 4, comprising an induction oven 24 and an induction oven 25 controlled by a thermostat (or just one induction oven), mounted on a carriage or table 26 which is fitted with a drive (not shown) causing it to displace longitudinally and is installed on horizontal guides 27. Rollers 28 on the table 26 serve to support the heated object 4 and prevent it from bending. For the subsequent cooling of the object 4, the table 26 also carries a cooling contrivances in the form of a ring-shaped sprayer 29 connected to a pump 30 which feeds a coolant from a tank 31.

For the transverse displacement of the object 4; the apparatus has a feeder 32 in the form of a roller table of an inclined rack with a leverage 33, and a take-away arrangement 34 with a leverage 35.

The apparatus incorporates a number of electrical and mechanical interlocking devices for starting and stopping the existing drives. These devices are all of known design and therefore their description is omitted.

The apparatus operates in the following way.

An object 4 to be treated (Figure 1), for example a pipe, is removed from the feeder 32 (Figure 3) and placed by means of the leverage 33 into a position wherein it is coaxial with the means 3 and 5 (Figure 1). Next, compressed air is admitted through the passage 7 into the cylinder of the drive 6, which causes the means 3 to move toward the means 5 similarly actuated by another drive 6, with the result that the object 4 (pipe) is clamped at the end of the bore between the means 3 and 5. The tapered end faces of the means 3 and 5, which abut against the object 4, are given a shape assuring gas-tightness of the bore.As soon as the leverage 33 returns to its initial position (Figure 3), carburizing gas automatically starts flowing from the system of pipes 1 7 and 1 8 (Figures 4 and 5) via the slide valve 19, reaching the bore of the object 4 via the pipe 16, the manifold 15, and the gas line 20 of the feeding means 3.

Once the bore is filled with carburizing gas, the drives 9 imparting rotary motion to the means 3 and 5 and the object 4 are automatically set into operation, and simultaneously a coolant serving to cool down the means 3 is admitted into the water manifold 22 (Figure 4) from the pipe 21. The means 5 is cooled by a similar arrangement. The water contained in the tank 31 (Figure 1 and 2) is fed by the pump 30 into the induction ovens 24 and 25 to cool them down and also is fed into the sprayer 29. Then the drive for longitudinal displacement of the table 26 is automatically energized as well as the means 23 for heating the object 4. The table 26 is set into motion along the object 4 so that it is heated by the induction ovens 24 and 25 in succession and then cooled by the sprayer 29.When the table 26 arrives into the position illustrated in Figure 2, the drive of the table 26 is automatically cut off and so is the supply to the induction heaters 24, 25 and to the drives 9 rotating the means 3 and 5.

After that, the bore of the object 4 is blown through with an inert gas admitted thereinto with the aid of the slide valve 19 (Figure 4) and then, when the blowing is finished, the leverage 35 (Figure 3) is automatically set into operation.

Simultaneously, compressed air is admitted into the passage 8 (Figure 4) of the drive 6, causing the means 3 to displace longitudinally. The means 5 is also displaced in the same way, with the result that both means, moving in opposite directions, release the object 4, which is transferred to the take-away arrangement 34 (Figure 3) in the form of, for example, a rack or a rolling table. The leverage 35, after transferring the object 4 to the take-away arrangement 34, returns to its initial position. At the same time, the longitudinal drive of the table 26 is set to operate in reverse, returning the table to its original position indicated in Figure 1. After that, at the end of travel the drive of the table 26 is automatically stopped and so is the pump 30 feeding coolant into the means 3 and 5. This completes the cycle of treating the object (pipe), and for treating the next object the procedure is repeated exactly in the same way.

Claims (4)

1. Apparatus for gas carburizing a bore in an object, comprising feeding means for feeding gas into the bore and discharging means for discharging gas from the bore, which means are cantilevered on corresponding brackets of a frame, longitudinal drive means for moving the feeding means and the discharging means towards each other so as to clamp the object at opposite ends of the bore, rotary drive means for causing the object to rotate together with the feeding means and the discharging means, a gas supply manifold which communicates with a gas line of the feeding means, means for heating and cooling means being; mounted on a carriage guided for movement paranel to the bore of the object clamped between the feeding and discharging means, and a drive for moving the carriage.

2. Apparatus as claimed in claim 1, wherein the feeding means gas has a cooling space for passing a coolant, the gas line being accommodated in the cooling space.

3. Apparatus as claimed in claim 1 or 2, wherein rollers for supporting the object are mounted on the carriage.

4. Apparatus for gas carburizing a bore in an object, substantially as described hetein with reference to, and as shown in, the accompanying drawings.