GB2167109A - Control system and valve arrangement for multi-leg mine roof supports - Google Patents

Abstract

A control system for a multi-leg mine roof support, comprising a main control valve 2, at least two leg circuits 4A, 4B, an auxiliary valves 6A, 6B associated with each leg circuit 4A, 4B, each auxiliary valve 6A, 6B comprising a valve body 9 having a main port 10, two ports 11 and 12 intersecting the port 10 and each port 11 and 12 housing a spring-loaded, poppet valve member 13, 14, the port 11 being intersected by an auxiliary inlet port 15 connectable to a pressure fluid supply line 7 which by-passes the main valve 2, the intersection being at a neck 16 between the valve member 13 and a head 17 carried by the neck 16, the head 17 being subjectable to fluid pressure within the port 10 and being displaceable from the port 10 to unseat the valve member 13 upon fluid loading on the head 17 being greater than spring loading in the opposite direction, a transfer port 19 connecting the port 11 downstream of the valve member 13 thereof to the port 12, the poppet valve 14 in the port 12 being openable upon fluid passing through the port 11 to the port 12 via the port 19, and thereby into the port 10, and the second poppet valve 14 being closeable under the influence of its spring 20 upon the fluid pressure in the port 10 equalling the fluid pressure in the port 12, the port 19 and the port 11, with a communicating bore 21 extending between the port 19 of the first valve body 9 and the or each second valve body 9, whereby manual opening of the first valve member 6A or 6B of any valve body 9 results not only in the opening of the second valve member 14 of that body under the action of pressure fluid within the ports 11, 19, 12, but also in the opening of the second valve member 14 in the or each second valve body 9 under the action of pressure fluid passing to the port 19 of the or each second valve body 9 via the communicating bore 21. <IMAGE>

Description

SPECIFICATION Control system for multi-leg mine roof supports, and valve arrangement for such system This invention relates to a control system for a multi-leg mine roof support of the self-advancing, hydraulically powered kind, as are used extensively in longwall mining operations; and to a valve arrangement for such a system.

In GB Patent 2042035 is described a control system in which maintenance of a connection between a hydraulically extensible chock leg along a pressure fluid feed line connected between the leg and a conventionally provided mains pressure line extending along a mineral face is ensured via an auxilliary valve, irrespective of how long a main, manually operable valve is kept open by the support operator, until the leg pressure stabilises at the mains pressure. However, with a chock having two forward and two rearward legs for example, with the legs extending between a base means seated on the mine floor and a common canopy engaging the mine roof, the front legs are, by regulation, on a different leg circuit from the rear legs, thus necessitating the presence of two of the auxilliary valves.However, because of irregularities in the mine roof it is frequently the case that the front of the canopy strikes the mine roof before the rear, or vice versa, and in this circumstance, it is often difficult for the operator to appreciate whether the front legs or the rear legs are urging the canopy into roof engagement, and hence which legs have first set, or are in the process of being set, to the roof by fluid pressure supply from the mains via the auxiliary valve of the leg circuit, while furthermore the "non-set" leg circuit may be at a fluid pressure below the nominal mains pressure e.g.

800 p.s.i., and the main valve of this low pressure leg circuit may be released prematurely by the support operator before the auxilliary valve has been triggered and hence before support leg pressure stabilisation at the mains pressure can be ensured by the auxilliary valve.

According to a first aspect of the present invention, there is provided a control system for a multileg mine roof support, comprising a main control valve at least two leg circuits, an auxilliary valve associated with each leg circuit, each auxilliary valve comprising a valve body having a main port, first and second ports intersecting the main port and each first and second port housing a springloaded, poppet valve member, the first port being intersected by an auxilliary inlet port connectable to a pressure fluid supply line which by-passes the main valve, the intersection being at a neck between the valve member and a head carried by the neck, the head being subjectable to fluid pressure within the main port and being displaceable from the main port to unseat the valve member upon fluid loading on the head being greater than spring loading in the opposite direction, a transfer port connecting the first port downstream of the valve member thereof to the second port, the poppet valve in the second port being openable upon fluid passing through the first port to the second port via the transfer port, and thereby into the main port, and the second poppet valve member being closeable under the influence of its spring upon the fluid pressure in the main port equalling the fluid pressure in the second port, the transfer port and the first port, with a communicating bore extending between the transfer port of the first valve body and the or each second valve body, whereby manual opening of the first valve member of any valve body resulting not only in the opening of the second valve member of that body under the ac -tion of pressure fluid within the first port, the transfer port, and the second port, but also in the opening of the second valve member in the or each second valve body, under the action of pressure fluid passing to the transfer port of the or each second valve body via the communicating bore.

According to a second aspect of the present invention, there is provided a valve arrangement for use in a multi-leg mine roof support control system, comprising at least two valve bodies, each comprising a main control valve at least two leg circuits, an auxilliary valve associated with each leg circuit, each auxilliary valve comprising a valve body having a main port, first and second ports intersecting the main port and each first and second port housing a spring-loaded, poppet valve member, the first port being intersected by an auxilliary inlet port connectable to a pressure fluid supply line which by-passes the main valve, the intersection being at a nedk between the valve member and a heard carried by the neck, the head being subjectable to fluid pressure within the main port and being displaceable from the main port to unseat the valve member upon fluid loading on the head being greater than spring loading in the opposite direction, a transfer port connecting the first port downstream of the valve member thereof to the second port, the poppet valve in the second port being openable upon fluid passing through the first port to the second port via the transfer port, and thereby into the main port, and the second poppet valve member being closeable under the influence of its spring upon the fluid pressure in the main port equalling the fluid pressure in the second port, the transfer port and the first port, with a communicating bore extending between the transfer port of the first valve body and the or each second valve body, whereby manual opening of the first valve member of any valve body results not only in the opening of the second valve member of that body under the action of pressure fluid within the first port, the transfer port, and the second port, but also in the opening of the second valve member in the or each second valve body, under the action of pressure fluid passing to the transfer port of the or each second valve body via the communicating bore.

Thus, the control system and valve arrangement in accordance with the invention, by ensuring that once a first auxilliary valve has been activated manually to connect the legs of its circuit to the pressure fluid supply line e.g., mains pressure line, or, if a setting pressure higher than mains pressure is required, to a boost pressure line then second or subsequent auxilliary valves are activated automatically, thus guaranteeing the setting at the supply line pressure of the legs on the or each other leg circuit, irrespective of whether the second or subsequent auxilliary valves are manually activated at all by the choke operator or manually activated for an insufficient period of time.

For a six leg support, either two or three auxilliary valves could be provided. With a two valve arrangement, one valve would form part of the leg circuit of the two forward legs, and the other valve would form part of the leg circuit of the four rearward legs. With a three valve arrangement, each valve would form part of individual leg circuits for the forward, middle, and rearward legs.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic arrangement of a control system in accordance with the first aspect of the invention; and Figure 2 is a sectional view through a valve arrangement in accordance with the second aspect of the invention.

In the drawings, a control system for a multi-leg mine roof support (not shown) having two forwardly located hydraulically extensible chock legs 1A (one only shown), and at least two rearwardly located hydraulically extensible chock legs 1B (one only shown), comprises a main control valve 2 supplied with pressure fluid from a line 3 connected to a pressure source, two leg circuits, being a forward leg circuit 4A for the forward legs 1A, and a reaward leg circuit 4B for the rearward legs 1B, with a line 5 extending between the main valve 2 and an auxilliary valve 6A associated with the leg circuit 4A and an anciliary valve 6B associated with the leg circuit 4B. A by-pass line 7 connects each auxilliary valve 6 to the line 3 at a location upstream of the main valve 2, the by-pass line 7 incorporating a shut-off valve 8.Each auxilliary valve 6A, 6B, comprising a valve body 9 having a main port 10, first and second ports 11 and 12 respectively intersecting the main port 10 and each first and second port 11, 12 housing a spring-loaded, poppet valve member 13, 14 respectively, the first port 11 being intersected by an auxilliary inlet port 15 connectable to the by-pass line 7 the intersection being at a neck 16 between the valve member 13 and a head 17 carried by the neck 16, the head 17 being subjectable to fluid pressure within the main port 10 and being displaceable from the main port 10 to unseat the valve member 13 upon fluid loading on the head 17 being greater than spring loading in the opposite direction by a spring 18, a transfer port 19 connecting the first port 11 downstream of its valve member 13 to the second port 12, the poppet valve 14 in the second port 12 being openable upon fluid passing through the first port 11 to the second port 12 via the transfer port 19, and thereby into the main port 10, and the second poppet valve member 14 being closeable under the influence of its spring 20 upon the fluid pressure in the main port 10 equalling the fluid pressure in the second port 12, in the transfer port 19 and in the first port 11; with a communicating bore, conduit, or flow line 21 extending between the transfer port 19 of the valve body 9 of the auxiliary valve 6A and the transfer port 19 of the valve body of the auxiliary valve 6B, whereby manual opening of the first valve member of valve 6A, or 6B results not only in the opening of the second valve memher of that valve under the action of pressure fluid within the first port, the transfer port, and the second port, but also in the opening of the second valve member in the (or each) second valve 6B or 6A, under the action of pressure fluid passing through the transfer port 19 and communicating bore, conduit, or flow line 21 of the (or each) second valve.

Claims (7)

CLAiMS

1. A control system for a multi-leg mine roof support, comprising a main control valve at least two leg circuits, an- auxilliary valve associated with each leg circuit, each auxilliary valve comprising a valve body having a main port, first and second ports intersecting the main port and each first and second port housing a spring-loaded, poppet valve member, the first port being intersected by an auxilliary inlet port connectable to a pressure fluid supply line which by-passes the main valve, the intersection being at a neck between the valve member--and a head carried by the neck, the head being subjectable to fluid pressure within the main port and being displaceable from the main port to unseat the valve member upon fluid loading on the head being greater than spring loading in the opposite direction, a transfer port connecting the first port downstream of the valve member thereof to the second port, the poppet valve in the second port being openable upon fluid passing through the first port to the second port via the transfer port, and thereby into the main port, and the second poppet valve member being closeable under the influence of its spring upon the fluid pressure in the main port equalling the fluid pressure in the second port, the transfer port and the first port, with a communicating bore extending between the transfer port of the first valve body and the or each second valve body, whereby manual operating of the first valve member of any valve body results not only in the opening of the second valve member of that body under the action of pressure fluid within the first port, the transfer port, and the second port, but also in the opening of the second valve member in the or each second valve body, under the action of pressure fluid passing to the transfer port of the or each second valve body via the communicating bore.

2. A valve arrangement for use in a multi-leg mine roof support control system defined in Claim 1, comprising at least two valve bodies, each comprising a main control valve at least two leg circuits, an auxilliary valve associated with each leg circuit, each auxilliary valve comprising a valve body having a main port, first and second ports intersecting the main port and each first and second port housing a spring-loaded, poppet valve member, the first port being intersected by an auxilliary inlet port connectable to a pressure fluid supply line which by-passes the main valve, the intersection being at a neck between the valve member and a head carried by the neck, the head being subjectable to fluid pressure within the main port and being displaceable from the main port to unseat the valve member upon fluid loading on the head being greater than spring loading in the opposite direction, a transfer port connecting the first port downstream of the valve member thereof to the second port, the poppet valve in the second port being openable upon fluid passing through the first port to the second port via the transfer port, and thereby into the main port, and the second poppet valve member being closeable under the influence of its spring upon the fluid pressure in the main port equalling the fluid pressure in the second port, the transfer port and the first port, with a communicating bore extending between the transfer port of the first valve body and the or each second valve body, whereby manual opening of the first valve member of any valve body results not only in the opening of the second valve member of that body under the action of pressure fluid within the first port, the transfer port, and the second port, but also in the opening of the second valve member in the or each second valve body, under the action of pressure fluid passing to the transfer port of the or each second valve body via the communicating bore.

3. A control system as claimed in Claim 1, for a six leg support, comprising two or three auxilliary valves.

4. A control system as claimed in Claim 3, incorporating two auxilliary valves, with one auxilliary valve forming part of the leg circuit of two forward legs, and the other auxilliary valve forming part of the leg circuit of the four rearward legs.

5. A control system as claimed in Claim 3, incorporating three auxilliary valves, with each auxilliary valve forming part of the individual leg circuits of the forward, middle, and rearward legs.

6. A control system substantially as hereinbefore described with reference to the accompanying drawings.

7. A valve arrangement substantially as hereinbefore described with reference to the accompanying drawings.