GB2147652A - Improvements relating to stopping doors in mine ventilation systems - Google Patents

Abstract

A door frame and stopping assembly for installing in mine roadway stoppings in which the door 10 is hinged at 7 to the top of the door frame and hangs down at an angle such that when it is the closed position, sealing surfaces around the periphery of the door are in face-to-face contact with the door frame, a latch 11 passing through the door can be rotated so that end 13 engages with a lug 14 when the door is dosed and is held securely in place against movement of the stopping by means of springs 15, 19. <IMAGE>

Description

SPECIFICATION Improvements relating to stoppings doors in mine ventilation systems So called "stoppings" are widely used in the mining industry and usually consist of a wall constructed of brickwork, concrete blocks or a steel fabrication, such a structure extends across the full width of the mine roadway which is to be sealed off, the ends of the stopping are recessed into the solid sides of the roadway in order to make the structure secure and minimise the leakage of air, in a similar manner the stopping extends from the roof of the roadway to the floor.Air stoppings serve two prime functions a) To provide an air-tight blockage between old, abandoned workings and the parts of the mine where mineral extraction is currently taking place thereby preventing a flow of air from the ventilating current into parts of the mine where it no longer needed thus allowing the maximum amount of air to be circulated and directed to the working sections of the mine. Conversely, the stoppings prevent the egress of potentially explosive and noxious gasses from flowing from the abandoned workings and fouling the ventilation system thereby endangering the lives of workmen.

b) The basic underground ventilation system consists of two or more parallel roadways leading from the mine entrance to the workings, one roadway is designated as the intake because it is along this roadway that the fresh air flows to the workings, the adjacent roadway acts as the return and along this flows the foul air on its journey to the surface. Because of the methods of mineral extraction, there are several inter-connecting roadways between the intake and return roadways. As the areas of mineral extraction advance, so it is necessary to erect stoppings across these roadways so directing the maximum amount of air to the mine workings and preventing any short circuiting of the ventilation system which will allow an escape of fresh air directly into the return airways and/or allow foul air to re-enter the flow of fresh air.

It is often desirable to instal an entry door in the structure of the stopping, these are often referred to as "man doors" and allow persons to pass through from one air roadway into another for the purpose of carrying out statutory examinations of the physical state of the roadway, obtain samples of the air for later analysis, measure the quantity of air flowing or take other essential ventilation measurements.

Such stoppings with built in man doors are well known in the mining industry and normally consist of a steel or timber frame set within the wall constructed of bricks, building blocks or steel sheeting, the door itself is made of timber or is a steel fabrication being attached by hinges to either of the vertical members of the frame and opening from the region of low air pressure into the region of high air pressure. The door is normally kept in the closed position by means of a latch on the door engaging with a hasp or keyed plate attached to the side of the frame which opposite to that on which the hinges.

Due to the special conditions which apply in the mining industry, the strata surrounding is in a constant state of movement created by the re-adjustment and settling of stresses of the subsiding strata. One aspect of this movement can be the uneven uplifting or heaving of the floor of the roadway, this action may result in the warping and displacement of the door frame with consequent unlatching of the door so allowing to be pushed or swing open, such a situation will allow the intake air to short-circulate the ventilation system and as the stoppings are usually located some distance from the main roadway, it may remain open for some length of time before the full effects are noticed.To a lesser degree, relative movement of the door frame members may cause gaps to appear between the abutting faces of the frame and the closed door so allowing excessive leakage of the air to take place so reducing the efficiency of the ventilation system. One other other possibility is the advent of a person passing through the door or doors and forgetting to close it or closing it and forgetting to properly latch it such that the door swings open a small amount and remains in that position for a long time.

The present invention relates to man doors incorporated in underground roadway stoppings and has for its object an improvement therein such that it will automatically close after a person has passed through, in addition, the door is latched to the frame and will remain secure even when the stopping is subjected to the animations of the surrounding subsiding strata and that the seal between the door and the abutting faces of the door frame will reduce air leakage to a minimum.

The invention will comprise for example a door frame and a door, the former is of a rectangular shape adapted to be mounted within an opening in a mine stopping, the top of the frame forming a lintel upon which the stopping above the opening will rest while the bottom member will bear on the stopping at the base of the opening, the two side members being attached to the previous members and extending from the base of the stopping opening to the top. The bottom member of the frame will extend forward beyond the vertical plane of the forward face of the top member of the frame while the two sides of the frame are inclined in a downward direction from the top member to the bottom member of the frame.The forward edges of the frame, each form a face which is engageable with the door, which is hinged to the top member of the frame, when it is swung down, the said door having a sealing surface around its periphery thereby sealing the opening in the frame when the door is closed and the sealing surface is in face-toface contact with the forward edges of the frame.

The frame is adapted to distort out of its rectangular shape without the door jamming or breaking the air seal. A latch is provided for latching the door closed, the latch comprises a bar extending through an opening in the door, one end of the bar is hooked and can engage with a projecting lug which is located on the bottom member of the door frame, the bar is capable of inward and outward movement through the door and is also capable of limited rotational movement in order for the hooked end to engage or disengage with the projecting lug.A compressive spring is slotted onto the bar and is located between the door handle and the door itself thus providing a bias to keep the door tightly sealed when the hook is in engagement with the lug of the bottom frame member, a further spring located within the door structure is in compression against a stop and the bar itself, alignment of this spring is ensured by a centering fitted at rightangles to the bar, the bias provided by this spring keeps the hook of the bar in place behind the lug provided on the bottom member of the door frame thereby reducing the risk of the hook becoming disengaged should strata pressure cause displacement of the frame.

In order that the invention may be fully understood and readily carried into effect, a preferred embodiment thereof will now be described, by way of example only, with reference to the drawings which accompany this specification, in which: Figure 1 shows a Front Elevation View of the invention as it would appear when sited within the stopping.

Figure 2 shows a Cross-sectional View of the invention along the line A-A.

A mine roadway stopping 1 may be built of brick, concrete blocks or panels of steel shuttering and it extends across the full width and height of the roadway, within the stopping is an aperture of a square or rectangular shape, around the perimeter of the aperture is located a frame whose constituent members may be formed from U channel sections with the webs thereof facing in an outward direction in order to key into the surrounding fabric of the stopping, the frame consists of a top lintel 2, a base member 3 and vertical right and left sides 4 and 5. To one web of the base member channel, being the web which faces in the same direction as the door, is attached another channel member 6 such that this second channel protrudes beyond the vertical plane of the wall and frame.To the webs of the vertical side members of the frame, being the webs which faces in the same direction of the door, are attached triangular or inclined sections 7 and 8, the inclined edge of these two sections are bent through an angle of ninety degrees to form a web, the base of the triangular sections extent in the same direction and for the same distance as the extending channel section 6 while their apex connect with the corresponding webs of the frame lintel, thus all four outer facing surfaces of the frame are in the same plane.A door 9 is formed of a metal plate and is hinged to the lintel of the frame by means of hinges 7 which allows the door to swing in a vertical arc, to the surface of the door which faces the door frame and around the outer edges of this surface is attached a sealing gasket 10 of rubber or some other elastomer, such that when the door is in the closed position, the sealing gasket and the outer edges of the inclined frame are in face-to-face contact so providing an airtight seal. A latch comprising a bar 11 extending through an opening 12 near to the bottom of the door structure, one end of the bar is bent to form a hook 13. This bar is capable of moving inward and outward in the opening and is also able to pivot in the opening, this pivotal movement allows the hooked end to engage or disengage with a protruding lug 14 located on the base member of the door frame. A spring 15 is concentric on bar 11 and is located between the latch handle 16 and the outer face of the steel plate door 9 thus providing the bar with a bias in the opening direction of the door. In order to ensure that the hooked end 13 of the bar is located securely behind the protruding lug when the door is closed, a coiled spring 17 is located within the door structure, provides a downward bias to the bar by being in compression between a stop 18 and a centering pin 19 on the bar.

Claims (6)

1. A door frame and door assembly for installation in an opening in a mine roadway stopping, comprising a rectangular frame having a lintel across the top, a bottom member bearing on the base of the opening and two side members attached to the lintel and bottom members, the side bottom member extends beyond the vertical plane of the frame while the two side members of the frame are inclined in a downward direction from the top lintel member to the edge of the bottom extended member, attached to the lintel by means of hinges is a door adapted to swing in a vertical arc, a latch bar passing through the door has a handle at one end and a hooked formation at the other end, the latch bar is capable of limited rotation in order for the hooked end to engage or disengage with a lug projecting from the bottom frame member, springs associated with the latch bar ensure bias to prevent opening of the door.

2. A door frame and door assembly as mentioned in Claim 1 wherein the top, bottom and side members of the frame are formed of lengths of U section beam with the vertical flanges of the facing in an outward direction in order to effectively key into the fabric of the mine roadway stopping.

3. A door frame and door assembly as mentioned in ciaims 1 and 2 in which the bottom member of the frame extends forward beyond the vertical plane of the frame while inclined portions extend forward from the top lintel member to the extended bottom member such that all four faces of the one side of the frame are in the same plane, the edges of these faces may be turned through an angle of 90 degrees to form flanges.

4. A door frame and door assembly as mentioned in any previous claim, in which a sealing gasket of rubber or some other elastomer is attached around the periphery of the door such that when the door is closed, the sealing gasket will be in face-to-face contact with the frame.

5. A door frame and door assembly as mentioned in any previous claim in which a spring is located around the latch bar, between the door and the handle of the latch, thereby providing a bias to keep the door tightly closed, a second compression spring is located within the door structure and bears against a stop and a centering pin on the latch bar and keeping the hooked end of the bar securely located behind the projecting lug on the bottom member of the frame.

6. A door frame and door assembly for installation in an opening in a mine roadway stopping, constructed and arranged substantially as herein described with reference to and as illustrated in any of the drawings accompanying this specification.