US3916631A

US3916631A - Mine roof support equipment

Info

Publication number: US3916631A
Application number: US447341A
Authority: US
Inventors: James Malcolm Agnew; Granville Collis James
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1973-03-16
Filing date: 1974-03-01
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04
Also published as: GB1449886A; DE2410967A1

Abstract

A mine roof support canopy is provided with an air-flow inducing device arranged to extract dust laden and and/or dust associated with the ventilation air flow and to direct the induced air flow away from the ventilation air flow.

Description

United States Patent 1 1 Agnew et al. Nov. 4, 1975 MINE ROOF SUPPORT EQUIPMENT 3,387,889 6/1968 Ziemba et al 299/12 3, 8 2 299 12 X 1 1 James Malcolm 3,212,252 5/1212 x Collis James, both of Englanii FOREIGN PATENTS OR APPLICATIONS [73] Asslgnee: Coal Industry (Patems) Limited 2,051,875 4/1972 Germany 61/45 D London, England 22 F'l d: M l 1974 1 1e ar Primary Examiner-Paul R. Gilliam [21] Appl. NO-I 4 ,341 Assistant Examiner'David H. Corbin Attorney, Agent, or Firm-James C. Wray [30] Foreign Application Priority Data Mar. 16, 1973 United Kingdom 12738/73 [57] ABSTRACT [52] US. Cl 61/45 D (:1. ..1 A mine roof upport anopy is provided an air- Fleld of Search 6l/45 flow inducing device arranged to extract dust laden 299/12 and and/or dust associated with the ventilation air flow and to direct the induced air flow away from the [56] References Cited ventilation air flow.

UNITED STATES PATENTS 2,032,404 3/1936 Fisher 261/116 11 Claims, 4 Drawing Figures US. Patent Nov. 4, 1975 Sheet 1 of 2 FIG. 2.

FIGJ.

US, Patsm Nov. 4, 1975 Sheet 2 of2 3,916,631

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MINE RGOF SUPPORT EQUIPIVENT This invention relates to mine roof support equipment and in particular although not exclusively the mine roof support equipment for installation along a longwall face.

It is conventional practice in an underground mine to have a plurality of mine roof supports installed side-byside along the length of a longwall working face. As the working face advances each of the roof supports, in turn is withdrawn from its mine roof supporting position, advanced towards the working face and reset to the mine roof. Unfortunately, if the mine roof is of a friable material, when the conventional roof support is withdrawn from its supporting position, broken rock material tends to fall from the sides of the roof engaging member into the main ventilation air flow along the face. The broken rock material usually contains a relatively high proportion of fine particles which are carried by the ventilation air flow giving rise to dust clouds.

An object of the present invention is to provide mine roof support equipment which reduces the above mentioned dust problem.

According to the present invention mine roof support equipment comprises at least one extensible hydraulic prop, a roof canopy supported by the prop, and apparatus for inducing air flow, the apparatus being arranged along the roof canopy.

Preferably, the apparatus comprises a member providing an elongated passage which is open at one end and a fluid outlet nozzle arranged to direct a jet of fluid along the passage towards the open end.

Advantageously, air-inlet means extend longitudinally along the member and in which case they may comprise a slot formed in the wall of the member and extending longitudinally along the member.

Preferably, the slot is generally wedge shaped, being tapered inwardly towards the open end of the passage.

The cross-sectional area of the passage may get smaller away from the open end of the passage.

The cross-sectional area of the passage may get smaller towards the open end of the passage.

The opposite end of the passage to the open end may be closed by a hinged flap.

The air-inlet means may be constituted, at least in part, by having the opposite end of the passage to the said open end at least partly open.

Advantageously, the roof support equipment comprises control means which control the supply of fluid to the fluid outlet nozzle.

By way of example only, one embodiment of the present invention will be described with reference to the accompanying drawings in which:

FIG. 1 is an incomplete perspective view of mine roof support equipment constructed in accordance with the present invention;

FIG. 2 is an incomplete end view of FIG. 1 drawn on an enlarged scale;

FIG. 3 is a longitudinal section through a detail of FIG. l; and

FIG. 41 is an end view of the detail of FIG. 3.

Referring to FIGS. 1 and 2 of the drawings, these show a part of a mine roof support installed along a longwall coal face in an underground coal mine. In the drawing only a part of one roof support is shown but in 2 operation a plurality of similar supports are installed side-by-side along the whole length of the working face.

The roof support comprises a plurality of legs 10 which are carried on a floor mounted base (not shown) and which support a roof canopy 11 extending from adjacent to the working face towards the goaf. The direction of the main ventilation current along the face is indicated by arrow X.

The roof support comprises apparatus 20 for inducing air flow, the apparatus being described in detail with particular reference to FIGS. 3 and 4. The apparatus 20 is secured along the downstream side edge of the roof canopy 11 by means (not shown) for example brackets bolted to the roof canopy. In other embodiments of the invention the apparatus is built into the roof canopy.

The apparatus 20 comprises a tubular member 21 providing an elongated passage 22 which is open at one end 23 and which is closed at the other end by a hinged flap 24. The flap can be raised to allow access to the passage 22.

A fluid outlet nozzle 25 is mounted on a radial arm 26 extending within the passage 22, the fluid supply being fed from a hose (not shown) via the arm to the nozzle. The nozzle is arranged to direct a jet of fluid, for example a liquid such as water, towards the open end 23 of the passage.

A generally wedged-shaped slot 27 is formed in the wall of the tubular member 21 and extends longitudinally along one side of the member. The slot 27 is tapered inwardly towards the open end 23 of the passage. A portion of the base of the tubular member 21 is cut away so that the cross-sectional area of the passage reduces towards the closed end, the cut-away portion of the circular tube being replaced by a plate 28.

In modifications of the apparatus the cross-sectional area of the passage approaching the open end 23 may reduce.

In further modifications of the apparatus the passage is other than circular in cross-section for example, the passage may have a square, rectangular or oval cross section.

In still further modifications of the apparatus the fluid outlet nozzle is located adjacent to the wall of the member. Some modifications of the apparatus comprise a plurality of fluid outlet nozzles.

In operation of the apparatus 20, fluid for example water, is fed to the outlet nozzle 25 via the radial arm 26 and is discharged as a jet directed towards the open end 23 of the passage 22. The jet of water is arranged to impinge on the wall of the passage and induces an air flow along the passage towards the open end of the passage, fresh air being drawn into the passage through the slot 27 which forms air inlet means. The slot 27 is tapered so that the resistance to air flow passing through any one portion of the slot reduces as the distance of the portion from the noule 25 is increased. Thus, fresh air tends to flow through the slot 27 along the whole length of the slot.

The cross-sectional area of the passage is reduced towards the closed end to ensure that a substantially constant air flow velocity is achieved along the length of the passage, i.e. where the quantity of air flow along the passage is less, the cross-sectional area of the passage is correspondingly reduced.

In the operation of the working face, as the face advances each of the roof supports is advanced in turn towards the working face. To advance a roof support,

the operator activates a control valve block (not shown) to retract the legs until the roof canopy 11 is clear of the mine roof. When the roof canopy is just clear of the roof an advancing ram (not shown) anchored to an armoured conveyor arranged along the working face advances the roof support. When the support is fully advanced the legs 10 are extended until the roof canopy is supporting the mine roof. The operation is then repeated with the next adjacent support.

One problem which frequently occurs when the mine roof is of a friable material is that when a conventional roof canopy is lowered from the mine roof, broken rock material tends to fall from the side of the roof canopy into the main ventilation air flow. The broken rock material usually contains a relatively large proportion of fine particles which are carried by the ventilation air flow giving rise to dust clouds.

However, with the roof support as shown in FIGS. 1 or 2 of the drawings, when the operator activates the control valve block to advance the support, control means (not shown) are provided on the roof support which feed a liquid, usually water, along a hose (not shown) to the outlet nozzle 25 within the passage. The water jet so produced induces an air flow out of the open end of the passage towards the goaf, air being drawn into the passage through the slot 27. Thus any fine particles of mineral falling over the side of the roof canopy 11 are drawn through the slot 27, into the passage 22 and then discharged through the open end 23 into the goaf. During the passage of the particles through the jet of water a high proportion tend to become wetted by the water and thereby fall to the goaf floor. The remainder are directed away from the main ventilation air flow and rather than forming a dust cloud tend to gradually settle onto the goaf floor.

When the roof canopy is reset to the mine roof, the control means cut off the water supply to the nozzle 25. The hinged flap 24 enables an operator to remove any particles of rock which may have settled inside the passage 22.

In modifications of the invention apparatus for inducing an air flow is provided on each side edge of the roof canopy.

We claim:

1. Mine roof support equipment comprising at least one extensible hydraulic prop, a roof canopy supported by the prop, and air flow inducing means for extracting 4 dust from near the roof canopy, the air flow inducing means including a member mounted along the roof canopy, an air-inlet means in the member for admitting dust and means mounted in the member to draw dust through the air-inlet means.

2. Equipment as claimed in claim 1, in which the member has an elongated passage which is open at one end, and wherein the means mounted in the member is a fluid outlet nozzle arranged to direct a jet of fluid along the passage toward the open end.

3. Equipment as claimed in claim 2, in which the air- .inlet means extend longitudinally along the member.

4. Equipment as claimed in claim 3, in which the airinlet means comprise a generally wedge shaped slot formed in the wall of the member and extend longitudinally along the member.

5. Equipment as claimed in claim 4, in which the slot is tapered inwardly towards the open end of the passage.

6. Equipment as claimed in claim 5, in which the cross-sectional area of the passage reduces in a direction away from the open end of the passage.

7. The mine roof support apparatus of claim 1 wherein the roof canopy has a side edge, and wherein the air flow inducing means is mounted on the side edge of the roof canopy.

8. The mine roof support equipment of claim 7, wherein the roof canopy extends longitudinally in a direction toward a working face of a mine and has side edges extending longitudinally, and wherein the air flow inducing means is mounted on the roof canopy along a longitudinally extending side edge of the roof canopy.

9. The mine roof support equipment of claim 8, wherein the equipment is mounted adjacent a main ventilation current flowing transverse to a longitudinal direction of the roof canopy, and wherein the member is mounted along a side edge of the roof canopy downstream with respect to the main ventilation current.

10. The mine roof support equipment of claim 7, wherein the member extends substantially all along the side edge of the roof canopy.

, 11. The mine roof support equipment of claim 7, wherein the air flow inducing means has a longitudi nally extending inlet slot positioned outward from the side edge of the roof canopy.

Claims

1. Mine roof support equipment comprising at least one extensible hydraulic prop, a roof canopy supported by the prop, and air flow inducing means for extracting dust from near the roof canopy, the air flow inducing means including a member mounted along the roof canopy, an air-inlet means in the member for admitting dust and means mounted in the member to draw dust through the air-inlet means.

3. Equipment as claimed in claim 2, in which the air-inlet means extend longitudinally along the member.

4. Equipment as claimed in claim 3, in which the air-inlet means comprise a generally wedge shaped slot formed in the wall of the member and extend longitudinally along the member.

11. The mine roof support equipment of claim 7, wherein the air flow inducing means has a longitudinally extending inlet slot positioned outward from the side edge of the roof canopy.