GB2038915A - Improvements Relating to Shearer Loaders - Google Patents

Abstract

A shearer loader mining machine has shearer drums on pivoted support arms at each end of the machine. Each drum requires a ventilation supply, particularly at the end face adjacent the seam, to dissipate methane or other gas, and preferably also a water supply to trickle nozzles to lay dust. This machine has a duct (21) along each support arm (4) leading into a fixed tube (15) coaxial with the drum and delivering at the end remote from the arm. The drive means, generally reduction gearing (12), surrounds the tube within the drum. An injection nozzle (23) at the root of the arm induces air through an intake (22) just downstream and thus well clear of the dust-laden drum cutting zone and conveyor. The air stream may then be directed through a venturi (24) and before entry to the tube (15) be boosted by a further injection nozzle (53). The tube can also be used, in conjunction with further members (34, 38, 41), to convey water to the trickle nozzles. <IMAGE>

Description

SPECIFICATION Improvements Relating to Shearer Loaders The invention relates to shearer loaders for underground mining. It is concerned with the shearer drum assemblies, which each have a shearer drum mounted rotatably on a support arm, and the ventilation of the drum end face near the mineral face by means of a stream of pressure medium produced by an injection nozzle and flowing through an axial passage in the drum drive shaft.

It has been proposed to provide the cutting head of a winning machine with liquid spray or trickle nozzles for dust suppression and with ventilating means. In one form, the injector nozzle required for ventilating the shearer drum zone near the face is disposed in a tube arranged centrally of the axis of rotation of the winning tool and is near the face. The stream of liquid produced by the nozzle induces an air flow along the tube. The required liquid is supplied to the trickle nozzles and the injector nozzle though separate lines.

There has also been proposed a mechanism in which a nozzle producing the air flow is disposed in a component arranged near that side of the loader frame which is remote from the face. In this case the injection nozzle co-operates with a tube which is arranged co-axially within the shearer drum. This tube supplies the liquid for dust suppression to the nozzles on the drum periphery. A stream of water is sprayed through the hollow shaft which drives the winning tool and extends around the tube to produce a flow of air towards the back of the cut. In this construction the injection nozzle receives its liquid through one line and the spray nozzle through another.

In both of these prior art systems the intake orifices of the ventilation duct are in the goaf region of the shearer drum and are therefore always in a place where there is very heavy soiling. Consequently, and particularly when the drum is required to undercut, the stream of air which the injection nozzle has induced immediately above the material on the face conveyor is bound to contain quite substantial amounts of dust. After quite a short period of operation the dust greatly restricts or even completely clogs the duct or passage available to the air flow. Ventilation of the drum end face adjacent the mineral face is therefore at least severely impaired and possibly completely inhibited.

It is therefore desirable to improve the ventilation of shearer loaders and prevent as much as possible accumulation of dust and muck in the air passages.

According to the present invention, there is provided a shearer drum assembly for underground mining machines, the assembly comprising a shearer drum rotatably mounted on a pivoted support arm and ventilating means for supplying air to the end face of the drum that is to cooperate with the mineral face, the ventilating means including a passage co-axially through the drum, a duct extending over at least some of the length of the arm and communicating at one end with said passage in the region of the drum axis, an air intake towards the other end of said duct, and an injection nozzle upstream of said intake connectable to a pressure medium line to produce an air stream in said duct and passage.

With this arrangement the air required for the drum end face at the back of the cut is taken from a region further away from the drum working zone than was previously the case, and-even in the lowest drum position-further from the face conveyor removing the mined material. There is therefore much less risk of dirt and muck entering the ventilation duct.

Advantageously, the ventilation duct is disposed on the goaf side of the support arm and extends to near the support arm pivot axis. This feature maximises the distance between the intake and the drum or face conveyor, and further protects the duct system.

Preferabiy, the passage is provided by a tube which extends through co-axial drive means for the drum, said tube having a delivery end adjacent said drum end face and being rigidly and nonrotatably connected at its other end to the support arm.

When the shearer drum has spray nozzles for dust suppression disposed on its periphery and/or end face, the tube conveniently has tubular members surrounding its end portions with clearance to form annular chambers, a first such member, extending substantially over the width of the support arm, being secured to the tube, and a second such member, at the delivery end of the tube, being rotatably mounted but axially confined on the tube and within the drive means, the chambers of the two tubular members being interconnected and forming part of a liquid conduit to said spray nozzles. These tubular members can be arranged so as not to impede assembly and dismantling of the shearer drum and can provide a reliable tight closure effectively preventing any of the trickling liquid from entering the reduction gearing within the drum.

Conveniently, said chambers are interconnected by a segmental-section duct within said tube, said duct being provided by a chordal barrier over a region of the tube nearest the support arm pivot axis. The reason for this arrangement is as follows. The bore diameter of the reduction gearing is of a given size and the tube providing the ventilation passage is of maximum diameter within that bore. The two tubular members defining the chambers are at the ends of the tube and to interconnect them exteriorly is generally impractical. Thus the intercommunicating duct is best within the tube, and the cross-section of the ventilation passage therefore has to be restricted slightly, but only in the intermediate region where for reasons of space it is generally impossible to fit an exterior tubular member.By arranging this restriction over the portion of the tube which is near the support arm pivot axis, from which direction the air is flowing and being swept round into the passage, the restriction does not appreciably impair the flow of the air, which in any event would concentrate on the opposite side of the passage.

In another preferred feature, to improve air conveyance and to boost ventilation of the drum end face, another injection nozzle is disposed coaxially of the shearer drum axis at said one end of the duct and is directed along said passage. This other injection nozzle is conveniently disposed at one end of a bore in an attachment at said one end of the duct, the other end of the bore being plugged and the zone between being connectable to a pressure fluid supply. This other injection nozzle can be fitted subsequently if required to supplement the first one or it can be used on its own to ventilate the drum end near the mineral face.

Preferably a venturi, symmetrical about its axis and with a shorter convergent entry portion than divergent exit portion, is disposed downstream of the intake of the ventilation duct. The injection nozzle upstream of the intake is conveniently adjustable for its spray cone to impinge on the entry of the venturi immediately upstream of the throat thereof. This can appreciably improve the air flow.

For a better understanding of the invention one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a rear elevation of a shearer loader; Figure 2 shows, partly in longitudinal section, a support arm of the machine of Figure 1; Figure 3 is a longitudinal section through one of the shearer drums, the reduction gearing being shown only in part; Figure 4 is a cross-section through a ventilation duct on the line IV--IV of Figure 7; Figure 5 is a section on the line V-V of Figure 2; Figure 6 is a sectioned view showing the shearer drum support arm in the region where the ventilation duct enters the drum, and Figure 7 is a section through the shearer drum at the delivery end of the ventilation passage.

A shearer loader 1 is disposed adjacent a face conveyor 2 in a coal-winning area; its leading shearer drum 3 cuts into the mineral seam presented to it while its trailing or rear shearer drum 3 works on the exposed roof strip. The two drums 3 are carried at the free ends of respective pivoted support arms 4 at opposite ends of the machine. They are vertically adjustable, the arms each pivoting about a horizontal axis transverse to the direction of machine movement. The machine 1 is advanced by means of a fixed chain 5 which extends over the length of the face and with which a sprocket 6 of a winch 7 engages for the machine to pull itself along. As it moves the machine 1 bears by way of skids 8, 9 or the like on the goaf side of the conveyor 2, the skids 8, 9 engaging around a tubular bar (not shown) which guides the machine.Within the winning area the machine 1 bears, for example by way of skids or runners (not shown), on a machine track or the like which is secured to the face side of the conveyor 2 and which bears directly on the floor, for example by way of a resilient skid or runner.

The material detached by the drums 3 is received by helical scrapers (not shown) on the drums 3 and discharged laterally onto conveyor 2.

The drum end faces which are adjacent the cut are ventilated to reduce the risk of explosion caused by accumulation of methane in that area.

Also, trickle nozzles (not shown) are provided on the peripheries of the two drums 3 and serve to ensure immediate precipitation at the place of origin of the dust evolved near the cutter picks 10.

Referring to Figure 3, which is a longitudinal section through one of the two drums 3, planetary reduction gearing 12 extends into drum body or envelope 11 and is coupled to further gearing or transmission within the support arm 4. The gearing 12 is releasably connected to the body 11 by way of flange 13. Its primary member is a pinion shaft 14 which projects co-axially into the drum from the support arm 4. It has a longitudinal bore receiving a torsion tube 1 5 which provides a longitudinal passage 1 6. The tube 1 5 extends through the shaft 14 over the whole width of the support arm 4 and projects beyond the flange 1 3 to a zone near the drum end face.There it terminates in a closure plate 1 7 having peripherally distributed ventilation ducts 1 8 which issue near the drum end face. The passage 1 6 serves as a continuation of a ventilation duct 21 extending along the arm 4 through which flows the air required to reduce the concentration of methane at the drum end face.

The tube 1 5 is rigidly secured, e.g. by welding, to a cover 19 which closes a recess 20 in the support arm 4 on the goaf side. The ventilation duct 21 is joined to the goaf side of the cover 1 9.

As best seen in Figure 2, at the root of the arm 4 there is an air intake grille 22 for the duct 21, and an injection nozzle 23 for spraying air-flowinducing water at high pressure into the duct 21 is disposed just upstream thereof. A venturi 24 downstream of the intake grilie 22 improves the throughput of air. The venturi 24 is symmetrical about its axis and has a relatively short convergent entry portion a and an elongated divergent exit portion b to ensure a substantially smooth flow of air through the swept curve orifice in the cover 19 and into the passage 1 6. The nozzle 23 may be adjustable either longitudinally of the duct or in its spray cone angle, so that the spray cone hits the venturi just upstream of the throat in portion a. To reduce flow resistance the tube 1 5 has a very large cross-section which takes up substantially the whole diameter of the bore in the pinion shaft 14.

Disposed alongside duct 21 is a liquid duct 25, shown in cross-section in Figure 5, via which the liquid required for operation of the trickle nozzles of the drum 3 is supplied. The water enters the duct 25 through an inlet orifice 26, and leaves via a recess 27 in cover 1 9. The recess 27 extends over substantially a quadrant curving around the end of duct 21 and is closed externally by a welded-on metal plate 28 (Figure 2). The cover 1 9 has an immediately contiguous corresponding recess 29, which is not connected to the recess 27 but is closed by the same plate 28 that closes the recess 27, the plate 28 being generally semicircular. This double recess arrangement enables the cover 1 9 to be used on either support arm 4.

The water entering the recess 27 flows through a port 30 in cover 19 and via further port 31 into an annular, inwardly facing groove 32 in a flange 33 welded to a tubular member 34 extending over substantially the whole width of the support arm 4. The member 34 surrounds the tube 1 5 with radial clearance over most of its length forming annular chamber 35, but reduces in diameter at the end remote from the flange 33 to be welded circumferentially to the tube 1 5. By way of the annular chamber 35 and a radial bore 36 trough tube 1 5 at said opposite end of the chamber, the water flows into a duct 37, which is a segment of passage 1 6 defined by a metal plate 38 as best seen in Figure 4.This plate is welded inside the tube 1 5 to provide a chordal barrier over the region nearest the pivot axis of the support arm 4, for the reason explained above.

The duct 37 connects the annular chamber 35, by way of a further bore 39 in tube 15, to an annular chamber 40 defined by a tubular member 41 beyond the pinion shaft 1 4 and surrounding the tube 1 5 with radial clearance (Figure 7).

In contrast to the member 34, which is fixedly welded to the tube 1 5, the member 41 is constrained only longitudinally relative to the tube 1 5. It has a shallow external annular rib 42 releasably engaging in a recess 46 formed by a two-part collar 43, 43a. This collar also serves as a bearing for the member 41 and is retained axially by a circlip 45. The collar 43, 43a is protected by means of two ring seals 44. Further seals 47 acting between the member 41 and the tube 1 6 provide a closure at both ends of the annular chamber 40. The chamber 40 communicates, by way of a port 48 in the member 41, with an annular groove 49 in the gearing 12 and thence by way of bores 50 with the trickle nozzles on the drum periphery.

As Figure 6 shows, the ventilation duct 21 can have fitted to it an alternafive or extra injection attachment 51. This has a bore 52 concentric of the drum axis, closed externally by a plug 54 and receiving internally an injection nozzle 53 which sprays along the passage 16, into the drum. The nozzle 53 can either boost the nozzle 23 or replace it to produce the air flow necessary to ventilate the drum end face. The nozzle 53 is screwed into the bore 52, and the zone between nozzle and plug communicates with a duct (not shown) which is supplied with the high pressure liquid necessary to produce the injection effect.

Claims (13)

Claims

1. A shearer drum assembly for underground mining machines, the assembly comprising a shearer drum rotatably mounted on a pivoted support arm and ventilating means for supplying air to the end face of the drum that is to cooperate with the mineral face, the ventilating means including a passage co-axially through the drum, a duct extending over at least some of the length of the arm and communicating at one end with said passage in the region of the drum axis, an air intake towards the other end of said duct, and an injection nozzle upstream of said intake connectable to a pressure medium line to produce an air stream in said duct and passage.

2. An assembly according to Claim 1, wherein the ventilation duct is dispoed on the goaf side of the support arm and extends to near the support arm pivot axis.

3. An assembly according to Claim 1 or 2, wherein the passage is provided by a tube which extends through co-axial drive means for the drum, said tube having a delivery end adjacent said drum end face and being rigidly and nonrotatably connected at its other end to the support arm.

4. An assembly according to Claim 3, wherein spray nozzles are disposed on the periphery and/or end face of the drum, and wherein said tube has tubular members surrounding its end portion with clearance to form annular chambers, a first such member, extending substantially over the width of the support arm, being secured to the tube, and a second such member, at the delivery end of the tube, being rotatably mounted but axially confined on the tube and within the drive means, the chambers of the two tubular members being interconnected and forming part of a liquid conduit to said spray nozzles.

5. An assembly according to Claim 4, wherein said chambers are interconnected by a segmental-section duct within said tube, said duct being provided by a chordal barrier over a region of the tube nearest the support arm pivot axis.

6. An assembly according to any preceding claim, wherein another injection nozzle is disposed co-axially of the shearer drum axis at said one end of the duct and is directed along said passage.

7. An assembly according to Claim 6, wherein said other injection nozzle is disposed at one end of a bore in an attachment at said one end of the duct, the other end of the bore being plugged and the zone between being connectable to a pressure fluid supply.

8. An assembly according to any preceding claim, wherein a venturi is disposed downstream of the intake of the ventilation duct.

9. An assembly as claimed in Claim 8, wherein the convergent entry portion of the venturi is of lesser length than the divergent exit portion.

10. An assembly according to Claim 8 or 9, wherein the injection nozzle upstream of the intake is adjustable for its spray cone to impinge on the entry of the venturi immediately upstream of the throat thereof.

11. An assembly according to Claim 8, 9 or 10, wherein the venturi is symmetrical about its axis.

12. A shearer drum assembly substantially as hereinbefore described with reference to the accompanying drawings.

13. A shearer loader having at each end an assembly as claimed in any preceding claim.