IE43181B1 - Process and apparatus for heat treating elongate thermal insulating shells - Google Patents

Abstract

1534597 Endless conveyers SAINT-GOBAIN INDUSTRIES 16 Sept 1976 [22 Sept 1975] 38370/76 Heading B8A Workpieces A, e.g. tubes, are conveyed through a hot gas heat-treatment zone at successive levels and in successive opposite directions, the workpieces being rolled the while about axes normal to their direction of movement. As shown the tubes are rolled along perforated plates 3 by bars 4 carried between a pair of endless chains 5. The upper and lower runs of the chains are used to convey the tubes in successive different directions. Transfer between the upper and lower runs and from one conveyer to the next is by gravity. The plates 3 may be inclined to the horizontal (Figs. 4 and 5, not shown). A particular application described is the heating of resin bonded fibrous shells in a gas-fired oven in order to harden the resin (Fig. 1, not shown).

Description

This invention relates to a process and apparatus for heat treating elongate thermal insulating shells in a chamber by hot gas of a required temperature and/or composition for treatment of the shells by contact with the gas.

The invention enables the size of a treating chamber to be less than that of a knoivn chamber, particularly in the direction of movement of .the shells, and at tin· same time ensures homogeneous and efficient heal- treat10 ment of shells..

According to the invention there is provided a process for heat treatment in a chamber by hot gas of elongate thermal insulating shells of fibres in which a binder is distributed, according to which motions of translation and of relation are imparted to each shell, wherein each shell Lj averses the chamber several times at different levels rolling over surfaces which are disposed at different levels in the chamber, such rolling being caused by contacting shells wi th members themselves subject to a motion of trans10 lation, which members cause each shell to pass through the chamber successively in one direction and then in the other at different levels, the hot gas being moved in the chamber so as to cause heat treatment of the shells at all the levels. The gas in the chamber may provide heat treat43181 - 3 meni. for polymerisation or hardening of the binder, The shells may, for example, be small diameter shells made of a felt in which a binder is distributed and having a permeable structure, with hardened and smooth internal and external surfaces.

Also according to lhe invention, in apparatus for carrying out. the process, a chamber may comprise at least I wo super imposed perforated plates on the surfaces of which the shells to be treated roll, and at least one endless chain subjected to a movement of translation and connected to members in contact with the shells, the upper run of the or each chain displacing shells in one direction on one perforated plate and the lower run displacing shells in the opposite direction on the other perforated plate, and wherein the chamber is heated by gas burners arranged at the bottom of the chamber, with gas deflectors above the burners, so that the shells on the surfaces of all the perforated plates are heat treated.

The invention will now be described by way of example, 2() wi th reference to the drawings in which:Flgure 1 is a part sectional elevation of an embodiment of the apparatus of the invention, and comprising an oven or chamber.

Figure 2 is a detail perspective view showing a 25 device for conveying and rolling shells through the chamber: Figure 3 is an enlarged section of a feed device forming part of tiie apparatus shown in Figure 1; and Figures 4 and 5 are detail sections of two variations. 181 - 4 The embodiment to be described relates to the application of the invention to cylindrical thermal insulating shells A made of felted fibres in which a plastics binder is distributed. The apparatus is designed to carry out substantially uniform heat treatment of the shells and to ensure polymerisation or hardening' of the binder.

During beat treatment in the chamber or oven, the shells are carried without constraint so as to avoid delamination of their outer layers and to prevent form10 ation of surface faults which ivould spoil their appearance. Also, while in the oven the shells are kept level over their length and carry out complete rotations about their axes so that the heat treatment is uniform throughout the thickness of each shell.

The shells A are successively brought to a vertically movable abutment or door 1 operated by a ram 2, the door slopping each shell for a short time before its introduction Into the oven, bo allow the shell to be properly positioned in relation to a driving member or bar 4· Opening of the door is controlled, so as to reduce heat loss from the oven.

To increase the time of stay of the shells in the oven while limiting the length of the latter, the oven has siveral superimposed levels, five in number in the pre25 sent embodiment (Fig. 3).

Each level has a perforated plate 3 having' one or more than one part on which the shells A are caused to roll by being driven by the bars 4 subject to a continuous motion of translation, produced by chains 5 connected (Fig. 2) to the bars. As seen in Figure 3 there are three pairs of - 5 4 3181 endless chains 5, each chain passing round and being driven by one of a pair of sprockets 6. The upper two pairs of chai ns move the sleeves in one direction by means of the upper chain runs and in the opposite direct5 ion by the lower chain runs. Thus each of the upper two chain pairs moves the sleeves at successive levels, but the lowest chain pair moves them in one direction only, as is apparent from Figure 3. Thus in the present embodiment there are five levels. The chains are driven by a single variable-speed drive unit (not shown).

Each shell A is carried between successive bars 4 on one of the perforated plates 3. Displacement of the pairs of chains 5 causes translation movement of the bars 4 (Fig. 2). Each shell A is pushed by the bar situated immediately upstream of it, and a motion of translation is thus imparted to it while rolling on the supporting plate 3. Between the end 9 of a plate and the last bar, in front of a pair of sprockets 6, is a space down through which a shell A can fall to the next lower level, Figure 3. At this next level, the bars 4 are driven in the opposite direction by the lower run of the pair of chains. The shells are therefore again moved horizontally under the same conditions but in the opposite direction to that in which they were previously moved at the next higher level. The shells finally leave the lowest level by rolling on an inclined plane 10.

The oven is heated by gas burners 12 at the floor 13 (Fig. l) and above which are domes 14 of stainless metal which prevent localised overheating of the lower level.

Even distribution of the hot ascending air through the whole height of the oven is provided for by a thin sheet oi perforate metal 15 which is parallel to the upper part of. (lie domes 14 and spared from them. 3181 - 6 After the heated air has passed over all the moving and rolling shells, it is exhausted through a chimney 16, such exhaust being controllable by a flap valve, Figure 1.

In the embodiment of Figures 1 to J the sleeves being treated are moved horizontally. In the variations shown in Figures 4 and 5, some of the levels may as shown be inclined to the horizontal. In Figure 4, the inclination is such that shells A ascend in the direction of displace10 ment, each shell being driven by the bar in contact with it. This provides for regular rotation of workpieces even if not exactly circular. In Figure 5, the inclination is such that shells A descend in the direction of displacement, shells being moved by gravity, and the bars 4 checking their movement. In addition to the advantage mentioned in connection with Figure 4, Figure 5 promotes evacuation of particles of matter which may have become detached from the shells during their passage through the oven.

Claims (11)

1. A process for heat treatment in a chamber by hot gas of elongate thermal insulating shells of fibres in which a binder is distributed, according to which motions of translation and of rotation are imparted to each shell, wherein each shell traverses the chamber several times at different levels rolling over surfaces which are disposed at different levels in the chamber, such rolling being caused by contacting shells with members themselves subject to a mol ion of translation, which members cause each shell to pass through the chamber successively in one direction and then in the other at different levels, the hot gas being moved in the chamber so as to cause heat treatment of the shells at all the levels.

2. A process according to claim 1, wherein the shells are cylindrical.

3. A process according to claim 1 or claim 2, wherein the heat treatment causes polymerisation or hardening of the binder.

4. Apparatus for carrying out a process according to any of claims 1 Lo 3, wherein the chamber comprises at least two superimposed perforated plates on the surfaces of which tiie shells to be treated roll, and at least one endless chain subjected (o a movement of translation and connected to members in contact with the shells, the upper run of the or each chain displacing shells in one direction on one perforated plate and the lower run displacing shells in fhe opposite direction on the other perforated plate, and wherein the chamber is heated by gas burners arranged at the bottom of the chamber, with gas deflectors above - 8 the burners, so that the shells on the surfaces of all the perforated plates are heat treated.

5. Apparatus according to claim 4 comprising a plurality of identical endless chains successively driving the shells, transfer of shells from one chain to the next being by gravity.

6. Apparatus according to claim 5 comprising a single drive unit for the endless chains,

7. Apparatus according to claim 6 wherein the drive unit 0 is a variable speed unit.

8. Apparatus according bo any of claims 4 to 7 wherein an abutment or door stops each shell for a short time before its introduction into the chamber, to allow the shell to be properly positioned in relation to a driving member. 5 9. Apparatus according to any of claims 4 to 8 wherein the plates are horizontal, the said members driving the workpieces. Id. Apparatus according to claim 9 wherein at least one ol the plates has a descending inclination in the direction 0 of workpiece displacement, the shells being moved by gravity, and the said members checking this movement.

9. 11. Apparatus according to claim 9 wherein at least one of the plates has an ascending inclination.

10. 12. A process for heat treating elongate thermal insul5 atLng shells substantially as herein described with reference to the drawings.

11. 13. Apparatus for heat treating elongate thermal insulating shells constructed and arranged substantially as herein described and shown ir the accompanying drawings.