GB2039362A - A pipeline having a compensation section for use in underground mine workings - Google Patents

Abstract

A ventilation pipeline 2 for use in underground mine workings has a fan 1 and downstream therefrom a section 3 with an opening 4 in its wall openable and closable by a pivoted plate 5. <IMAGE>

Description

SPECIFICATION A pipeline and a compensating section for use in underground mine workings The invention relates to a pipeline and a compensation section for use in underground mine workings.

Such apparatus can be used for avoiding the opening shock upon starting up ventilators and for compensating pressure waves, in particular in underground pipelines of flexible material, as well as for use as a compensation pipe in a ventilating cooler operated with a special ventilator as well as also for diluting blasting vapours andlor clouds of CH4 after a special ventilation installation has been switched on again.

The use of flexible pipelines, in particular in roadway-driving operations using blasting, has many advantages so far as conveyance and suspension of the pipeline are concerned but imports the disadvantage that the pressure waves caused by the blasting operation proceed at different speeds in the pipe and in the roadway and lead to great damage, and under certain circumstances to destruction of the pipeline.

A further disadvantage of flexible pipelines resides in the loading of the pipe skin by the additional mass accelerations which are effected upon starting up the ventilators, by the sudden filling out of the pipeline.

This so-called opening shock of the pipeline leads to tearing of the weld seams as well as to pulling out of the suspension means at the roof of the roadway, owing to the sudden movement which travels through the pipeline. Moreoverthe-connecting rings of the pipe sections may be torn open and the pipeline interrupted in this way.

Particular difficulties will occur when the ventilation of roadway-driving operations is restarted in the presence of CH4. The purging of the roadway must then be effected in such a manner that the permissible CH4 li-mits in the exhaust stream are not exceeded.

Furthermore, a particular problem is to be seen in the connection of the pipeline with the special ventilator of the cooler within the ventilation guide, in particular in roadway-driving with two-slice machines. Usually a compensation pipe is built into the pipeline in front of the special ventilator. Upon switching the cooler ventilator off which is mostly connected to the supply of the roadway-driving operation, the cooling and the ventilation.of the workface is interrupted. The ventilation gases do not flow for the largest part through the cooler, but escape uncooled into the roadway through the compensation pipe. Thereby, however, the safety of the miners working at the face is highly endangered.

According to the invention, there is provided a pipeline for use in underground mine workings which has a fan for passing gas through the pipeline, and a compensation pipe section on the pressure side of the fan, the section having a through passage between its ends and an opening in its wall with an adjustable flap which can be moved to open or to close the opening.

The flap closing the opening from the inside may be adjusted in cross-section approximately to the curvature of the pipe and may be adjustable by means of an opening mechanism.

The compensation pipe section may alternatively be provided with a flap which closes the opening from the outside and which in cross-section comprises a curvature adjusted to the compensation pipe, and an opening mechanism.

The most important advantage of the invention; however, is to be seen in the fact that the compensation pipe which is provided with an opening and an adjustable flap closing the opening may be used as à pressure wave compensator, a starting-up aid, or as a vapour diluting means and as a control flap for coolers in pipe assemblies.

Further preferabLe features of the invention are set forth in the sub-claims.

The technical advance of the invention is based on the fact that a series of grave problems occurring in the ventilating technique are solved in an economically favourable manner with one and the same compensating pipe section; such problems occur.

when pipelines of flexible material are used; in this solution, the safety of the miners working at the face is a foremost consideration; moreover, for example for the purpose of diluting CH4 which issues frorn the gangue, such devices for diluting and mixing are insertab!e additionally at any desired location of a long pipeline.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a section through a compensation pipe section according to the invention with an opening and closing mechanism, Figure 2 is a side view of the pipe section of Figure 1, showing the opening and closing mechanism, Figure 3 schematically illustrates the use of a pipeline according to the invention as a vapour diluting means and pressure wave compensator, Figure 4 shows a further example of use of a pipeline according to the invention as a starting-up aid, Figure 5 shows the use of a pipeline according to the invention as a compensation pipe in conjunction with a special ventilation installation provided with a cooling device, and Figure 6 is an embodiment of the compensating pipe section according to the invention with a flap closing the opening from the outside.

The compensation pipe section 3 illustrated in section in Figure 1 has an opening 4 in the pipe wall 13, the opening being constructed to be openable and closable by means of a flap 5 which can be swung inwardly by means of an opening mechanism 6. In the embodiment illustrated, the opening mechanism 6 provided is a hydraulically actuable adjuster device. The cylinder 10 is attached to the compensation pipe section 3 in a pivotal manner by means of a lug 8 and actuates a lever 9 which in turn is pivotally connected to the flap 5 which is illustrated by broken lines. However, the opening mechanism 6 can alternatively be controllable by mechanical, electrical or pneumatic means. The flap 5 is pivotally attached along a hinge axis which is parallel to the axis of the compensation pipe section 3.The axial pivotal connection by means of hinges 7 is clearly visible in the side view according to Figure 2.

The flap 5 as well as the rim of the opening 4 is provided with sealing means, for example foam rubber In one manner of working of the compensation pipe section 3, a ventilation short-circuit is produceable in a pipeline 2.

According to the example of use illustrated in Figure 3, of the compensation pipe section 3, the same is employed in the manner of working as a vapour diluting means. In a roadway 14 which is illustrated in diagrammatic form and in which the driving operation is performed by means of drilling and blasting, the special ventilation indicated in the drawing is necessary. Afan 1 is installed in a roadway 15, for example in a cross-cut, and the pipeline 2 of flexible material is laid in the roadway 14 to a location close to the face. The path of the ventilating gases on the pressure side of the fan 1 is indicated by the arrows A and B. Upon demand, that is to say after performance of the blasting operations or even upon the occurrence of methane layers the opening 4, which is constructed to be opened or closed by means of a flap 5, is opened a certain amount.The stream which then issues tangentially to the outer surface in the direction of the arrows drawn in full lines is subject to the known Coanda effect by means of which the whirling of air layers in the roadway cross-section is initiated. In order to obtain tangential flowing off in the sense of the Coanda effect a curved metal plate 11 is securely installed (Figure 1) within the compensation pipe section 3 and permits a nozzle effect to be obtained by the formation of a slot 12 between the plate 11 and the outer wall 13 upon closure of the flap 5 from inside towards the outside.

It may be envisaged that the flap 5, or the guide plate 11 which is curved and required for forming the slot, respectively, is produced as a unit.

The example of use illustrated in Figure 3 is not only for diluting vapours, but can also be used for compensating pressure waves. The pressure wave produced by the blasting operation is propagated within the roadway and within the pipeline 2 with a phase displacement which is smaller the lower the speed difference between the ventilating gases within and outside the pipeline 2. When the opening 4 within the pipe section 3 is opened by means of the opening mechanism 6, the flow speed in the pipe section at risk is reduced and simultaneously a phase displacement within and outside the pipe is consciously prevented. Moreover the pressure wave which still travels ahead slightly in the roadway can compensate through the opening 4 the pressure difference in the pipeline 2 and thus nearly cancel the phase displacement.

In the diagrammatically illustrated view from above according to Figure 4, the use of the pipeline as a starting-up aid for the ventilator fan 1 is illustrated.

The volume of the ventilating gas stream from the ventilator 1 in the direction of the arrow A is reduced within the pipeline 2 by the outlet stream at the opening 4, so that the pipeline 2' extending into the roadway 14 is blown up only by a partial ventilating gas stream. In this way the effect, usually known as opening shock, which occurs over the entire pipeline 2,2', is avoided. Owing to the adjustability of the flap 5 the partial gas stream is adjustable in such a manner that blowing up of the pipeline 2' occurs in such a slow manner that no damage is caused.

At the same time the compensation pipe section 3 arranged at the start of a roadway 14 can be used not only for starting up, but again also as a vapour diluting means and as a pressure wave compensator.

The use illustrated in Figure 5 of the compensation pipe section 3 as pressure compensation in the sequence: ventilator fan 1, pipeline 2, compensation pipe section 3, a special ventilator 16 and ventilatiqn cooler 17 has the object of exhausting a controlled, uncooled partial ventilating gas stream of the main pipeline 2 into the free roadway space.

The special ventilator 16 is switched of frequently, particularly if it is connected to the supply of the roadway 14. When the special ventilator 16 stops, the cooling and the air supply to the work face is interrupted. Merely a small portion of the gases flow through the cooler 17. The major portion escapes through a preceding pipe into the roadway. By closing the opening 4 by means of the adjustable flap 5 the gases of the pipeline 2 are forced to flow through the cooler 17. Admittedly the increased flow resistance must be overcome by the ventilator fan 1 in the pipeline 2, but a certain cooling power is produced and ventilation at the face is ensured.

When the compensation pipe section 3 is used for diluting vapours or outflows of gas, it is possible to arrange the flap 5 outside the pipe section 3 to cover the opening 4. In such an embodiment (see Figure 6) the guide plate 11 may be omitted and the nozzle effect can be obtained by opening the flap 5 to define a slot 12 between the flap 5 and the pipe wall 13. The outer casing is of nozzle-like construction in the axially arranged region of the air outlet. The edge of the opening 4 can be specially shaped as shown in Figure 6 to impove the characteristics of the flow 12.

An elastic pad 18 can be fixed to the outside of the pipe section 3 for the flap 5 to seal against.

The pipe section 3 can have flanges at each end by means of which it can be built into a ventilation pipe.

The pipe section 3 shown in Figure 1 can have an external casing constructed in the form of a nozzle in the axially arranged region of the air outlet.

In one arrangement, fans are connected in parallel, the compensation pipe section 3 being arranged immediately behind the branched pipe which leads the ventilation streams together to form a common ventilation stream.

Claims (15)

1. A pipeline for use in underground mine workings which has a fan for passing gas through the pipeline, and a compensation pipe section on the pressure side of the fan, the section having a through passage between its ends and an opening in its wall with an adjustable flap which can be moved to open orto close the opening.

2. A pipeline as claimed in claim 1, wherein, when seen in a cross-section through the pipe section, the flap has a curvature which follows the curvature of the pipe section.

3. A pipeline as claimed in claim 1 or claim 2, wherein the flap is movable into the interior of the pipe section to open the opening.

4. A pipeline as claimed in any preceding claim, including a plurality of compensation pipe sections, all arranged on the pressure side of a fan.

5. A pipeline as claimed in any preceding claim, wherein the flap is hinged to the wall of the pipe section, about a hinge axis which extends parallel to the pipe section axis.

6. A pipeline as claimed in any preceding claim, wherein sealing means are provided between the flap and the wall of the pipe section around the opening.

7. A pipeline as claimed in claim 6, wherein the sealing means is foam rubber.

8. A pipeline as claimed in any preceding claim, including a fixed curved guide plate positioned inside the pipe section adjacent the opening and spaced from the internal wall of the pipe section to form a guide slot for air passing out through the opening.

9. A pipeline as claimed in any preceding claim, wherein the compensation pipe section is arranged directly adjacent the pressure side of the fan.

10. A pipeline as claimed in claim 1, wherein fans are arranged in parallel and the compensation pipe section is arranged immediately behind a branched pipe which leads gas streams together to form a common stream.

11. Apparatus as claimed in claim 1 or claim 2, wherein the flap is movable outside the pipe section to open the opening.

12. Apparatus as claimed in any one of claims 1 to 10, wherein the compensation pipe section is provided with an external casing constructed in the form of a nozzle in the axially arranged region of the air outlet.

13. A compensation pipe section for inclusion in a pipeline in an underground mine working, the section having a through passage between its ends and an opening in its wall with an adjustable flap which can be moved to open or close the opening.

14. A pipeline for use in underground mine workings, substantially as herein described with reference to Figures 1 and 2 or Figure 3 or Figure 4 or Figure 5 or Figure 6 of the accompanying drawings.

15. A compensation pipe section substantially as herein described with reference to Figures 1 and 2 or Figure 6 of the accompanying drawings.