GB2167162A

GB2167162A - Stop valve arrangement

Info

Publication number: GB2167162A
Application number: GB08527114A
Authority: GB
Inventors: David Raymond Oldroyd; Malcolm Wake
Original assignee: Fletcher Sutcliffe Wild Ltd
Current assignee: Fletcher Sutcliffe Wild Ltd
Priority date: 1984-11-14
Filing date: 1985-11-04
Publication date: 1986-05-21
Also published as: GB8527114D0; GB8428789D0

Abstract

A stop valve arrangement, 1 for a hydraulically powered, self- advancing mine roof support, comprising a valve body 2, a fluid flow port 3 extending through the valve body 2 from a fluid inlet end (4) to a fluid outlet end 8, a first valve 9 comprising a valve seat 10 located intermediate the port ends and an associated valve member 21 manually displaceable between an open position in which fluid flow through the port 3 is allowed as the valve member 21 is spaced from its seat 10, and a closed position in which fluid flow through the port 3 is prevented as the valve member 21 is in engagement with its seat 10; a second valve 28 in fluid flow communication with the port 3, the second valve 28 comprising a valve seat 37 and an associated valve member 33, the latter being displaceable via a ball 29, by the first valve member 21, 20, 23, 24 upon displacement of the first valve member 21, 20, 23, 24, between a closed position when the first valve 9 is in its open position, and an open position when the first valve 9 is in its closed position, with the second valve member 33 in its open position permitting fluid flow/exhaust from the port 3. <IMAGE>

Description

SPECIFICATION Stop valve arrangement This inventon relates to a stop valve arrangement, for use with fluid pressure operable equipment, and capable of isolating the equipment, particularly in an emergency situation, from the associated source of fluid pressure, which may be compressed air or hydraulic fluid such as water, oil or a water/oil emulsion.

For example, hydraulic equipment in the form of self-advancing mine roof supports incorporate several hydraulically extensible and retractable piston and cylinder units being, a multiple number of generally vertically arranged chock legs extending between a floor engaging base means and a roof engaging canopy means and at least one generally horizontally arranged advancing ram extending between the supports and an associated scraper chain conveyor for support, and conveyor, advancing purposes, with possibly a forward and/or rearward forepoling beam ram, and possibly a sprag plate ram.To actuate the piston and cylinder units such as those exemplified above, the standard arrangement is to provide a mains, service pressure line extending along the conveyor and hence along the associated mineral face, and a mains return or exhaust line, with feed and exhaust hoses extending between the supports and these lines, to take pressure fluid from the pressure line and to exhaust fluid to the exhaust line, as demanded by the roof support in accordance with the normal retraction, advance, and resetting sequence of a support. It is not uncommon however for back pressures to be generated in the exhaust line, and consequently for pis ton and cylinder units open to the exhaust line to be actuated inadvertently, even if only a creeping speed, with the consequent risk of mine personnel being- trapped by the hydraulic equipment and/or the associated hoses.This back pressure exhaust problem is not of course confined to mine roof supports, but is common to any equipment employing multiple numbers of fluid pressure operated devices connected to a common exhaust.

Hazardous inadvertent operation of a roof support has also been known to occur from a remote command source. Thus, when using the so called adjacent control system, a roof support operator located within the safety of a first roof support set to the roof and advancing a second, adjacent roof support by operation of valve gear on the first roof support could find that movement of hydraulic hoses extending between the first roof support and a third roof support inadvertently actuates the valve gear of the second roof support which, because of the adjacent control connections, inadvertently puts the first roof support into its advancing sequence. A similar possibility exists when operating the so called batch control system.

According to a first aspect of the present invention there is provided a stop valve arrangement comprising a valve body, a fluid flow port extending through the valve body from a fluid inlet end to a fluid outlet end, a first valve comprising a valve seat located intermediate the port ends and an associated valve member manually displaceable between an open, position in which fluid flow through the port is allowed as the valve member is spaced from its seat, and a closed position in which fluid flow through the port is prevented as the valve member is in engagment with its seat; a second valve in fluid flow communication with the port, the second valve comprising a valve seat and an associated valve member, the latter being displaceable by the first valve member upon displacement of the first valve member, between a closed position when the first valve is in its open position, and an open position when the first valve is in its closed position, with the second valve member in its open position permitting fluid flow/exhaust from the port.

According to a second aspect of the present invention there is provided a hydraulic circuit for a hydraulically powered, self-advancing mine roof support, comprising a mains, pressure line; a feed line to the support from the pressure line, and a stop valve arrangement as defined above incorporated in the feed line.

According to a third aspect of the present invention, there is provided a hydraulically powered, self-advancing, mine roof support incorporating a hydraulic circuit as defined above.

It will be appreciated that when the stop valve of the first aspect of the invention is incorporated in the circuit of the second aspect of the invention of a roof support of the third aspect of the invention, then any inadvertent actuation of a piston and cylinder unit of the roof support, resulting for example from back-pressure in the exhaust line, can be not only halted from further displacement by actuation of the stop valve, but by the resultant opening of the second valve, the pressure is automatically relieved. The stop valve is therefore available for emergency use. It will also be appreciated that if back-pressure in the exhaust line is causing the inadvertent piston and cylinder actuation, then exhausting the back pressure to atmosphere by the second valve is desirable, rather than a further connection to exhaust being made.

It is preferred for both the first and second valves to be of the poppet type. Preferably, the first valve member is mounted on a longitudinally displaceable spindle having an enlarged diameter head, a necked portion, and an interposed frusto-conical portion, the necked portion constituting, with a roller, ball or other curved surface provided on the sec ond valve member, a detent arrangement, whereby the respective valve members may be latched in positions in which fluid flow to the associated equipment is possible i.e., with the first valve open and the second valve closed.It is obviously desirable that when the stop valve arrangement has been actuated, to cause firstly isolation of the fluid pressure supply from the equipment and secondly ex hausting of the fluid pressure that would otherwise be retained within the port, the relevant valve dimensions are such that fluid flow and/or pressure does not result in the second valve being reseated. Conveniently, the roller, ball or curved surface of the second valve is carried at one end of a spindle extending from the valve member. It is preferred for the spindles of the first and second valves to be displaceable along orthogonal axis. It is thus necessary to provide the valve body with a first bore to receive slidably at least a portion of the first valve spindle and a second bore, extending radially from the first bore, to receive slidably at least a portion of the second valve spindle.

In detail, the first bore may be counterbored for accommodation at an inner end of the counterbore of the first valve seat, with the counterbore preferably tapped towards its outer end to receive a screw in bush to slidably support a shaft extending from the opposite side of the valve head to that of the spindle. The shaft preferably has a threaded terminal end on to which is screwed a manually operable push-pull button located externally of the valve body, the bush itself preferably being counterbored to receive an internally threaded connection stem of the pushpull button. The second bore may be similarly counterbored for accommodation at the inner end of the counter bore of the second valve seat, with a closure plug being screwed into a tapped outer end of this bore.

Thus, manual operation of the first valve is effected by the button being pulled outwardly, to open the first valve, to allow the associated equipment access to the source of pressure fluid, in which outer position the roller, ball or curved surface of the second valve engages the necked portion of the first valve spindle, thus closing the second valve. Maintenance of contact of the second spindle with the first spindle may be assisted by providing the second valve member with a spring e.g., a coil compression spring, rather than by relying on fluid pressure within the port and relative valve member/spindle dimensions.It follows that when the stop valve arrangement is displaced to its emergency stop condition i.e. the button is pressed or knocked inwardly, to close the stop valve arrangement, the roller or ball of the second valve spindle rides up the frustoconical surface, thereby progressivly displacing the second valve spindle, and hence its valve member, towards an open position.

The port of the valve body may be linear or stepped, depending on the required locations for the inlet and outlet ends.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial sectional view through a stop valve arrangement in accordance with the invention; Figure 2 is a side elevation in the direction of arrow A of Figure 1; and Figure 3 is an end elevaton in the direction of arrow B of Figure 1.

In the drawings, a stop valve arrangement 1 can be seen to comprise a valve body 2 with a fluid flow port 3 extending therethrough and comprising a fluid supply port 4, connectable to a source of pressure fluid, a fluid supply chamber 5, a first port portion 6, and a second port portion 7 at 90" to the portion 6 and terminating in fluid delivery end 8.

Within the fluid flow port 3, and specifically between the supply chamber 5 and the first port portion 6 is located a first valve 9 capable of allowing, in its open position, or preventing, in its closed position, flow of pressure fluid from the chamber 5 to the first port portion 6. In detail, the first valve 9 is of the poppet type comprising a valve seat 10 located at an inner end of a counterbore 11 and retained by a closure bush 12 screwed into a tapped, outer end of the counter bore and having a fluid seai 13. The bush 12 is provided with a through bore 14 and with a counterbore 15 in which is slidably located a stem 16 of a manually operable push/pull button 17 having a head 18.The stem 16 is internally screw threaded to receive a threaded shaft 19 of larger diameter than a spindle 20 of the first valve 9, the shaft 19 being a sliding fit within the through bore 14 and, within the chamber 5, an enlarged valve member 21 is provided, having a frusto-conical face 22 to engage the valve seat 10 in the closed position. Beyond the valve member 21 the spindle 20 continues across the second port portion 6 where an enlarged diameter head 23 of the spindle, with a frusto-conical surface 24, and a terminal head 25 are slidably located within a bore 26, the heads 23 and 25 being interconnected by a necked portion 27, and the bore 26 making fluid flow communication with the second port portion 6 when the first valve 9 is closed.

The necked portion 27 and surface 24 are engaged by a second valve 28, also of the poppet type and specifically by a ball 29 to constitute a detent arrangement on which ball 29 seats a terminal head 30 of a spindle 31 of the second valve, the head 30 being slidably located in a bore 32 which is in fluid flow communication with, and orthogonal to, the bore 26. The spindle 31 extends from the head 30 to an enlarged valve member 33 hav ing a frusto conical face 34 and located in an exhaust chamber 35, which is in permanent fluid flow communication with an exhaust outlet 36, the face 34 engaging a valve seat 37 in the closed position illustrated. Again, the valve seat 37 is located at an inner end of a counterbore 38 and is retained by a closure bush 39 screwed onto a tapped outer end of the counterbore and provided with a fluid seal 40.

In normal operation of the stop valve arrangement 1, the first valve 9 is open, and consequently the second valve 28 is closed, thus permitting fluid flow from the supply port 4 to the supply chamber 5, to the first port portion 6, to the second port portion 7, with fluid delivery at the end 8. Although pressure fluid-will leak past the heads 23, 25 and 30, and.consequently be present in bores 26 and 32, this is of no consequence for no flow to the exhaust outlet 36 can occur as the second valve 28 is closed.

When it is desired to activate the stop valve arrangement 1, to stop fluid flow to the end 8, the button 17 is pressed or knocked inwardly to close the first valve 9 with its valve member 21 engaging the valve seat 10, to stop any further fluid flow from the chamber 5. Simultaneously with such engagement, the surface 24 displaces the ball 29 and hence the spindle 31, thereby unseating the valve member 33 of the second valve 28 from engagement with its seat 37, so putting the bore 32 into fluid flow communication with the exhaust outlet 36, and consequently permitting fluid to exhaust from the port 3, and specifically from the first port portion 6, into the bore 26 and thereafter into the bore 32.

The second valve 28 is maintained in its open position by the action of pressure fluid within the chamber 5 on the valve member 18.

Claims

1. A stop valve arrangement comprising a valve body, a fluid flow port extending through the valve body from a fluid inlet end to a fluid outlet end, a first valve comprising a valve seat located intermediate the port ends and an associated valve member manually displaceable between an open, position in which fluid flow through the port is allowed as the valve member is spaced from its seat, and a closed position in which fluid flow through the port is prevented as the valve member is in engagment with its seat; a second valve in fluid flow communication with the port, the second valve comprising a valve seat and an associated valve member, the latter being displaceable by the first valve member upon displacement of the first valve member, between a closed position when the first valve is in its open position, and an open position when the first valve is in its closed position, with the second valve member in its open position permitting fluid flow/exhaust from the port.

2. A stop valve arrangement as claimed in Claim 1, wherein both the first and second valves are of the poppet type.

3. A stop valve arrangement as claimed in Claim 1 or Claim 2, wherein the first valve member is mounted on a longitudinally displaceable spindle having an enlarged diameter head, a necked portion, and an interposed frusto-conical portion, the necked portion constituting, with a roller, ball or other curved surface provided on the second valve member, a detent arrangement, whereby the respective valve members may be latched in positions in which fluid flow to the associated equipment is possible.

4. A stop valve as claimed in Claim 3, wherein the roller, ball or curved surface of the second valve is carried at one end of a spindle extending from the valve member.

5. A stop valve arrangement as claimed in any preceding Claim, wherein the spindles of the first and second valves are displaceable along orthogonal axis.

6. A stop valve arrangement as claimed in Claim 5, wherein the valve body is provided with a first bore to receive slidably at least a portion of the first valve spindle and a second bore, extending radially from the first bore, to receive slidably at least a portion of the second valve spindle.

7. A stop valve as claimed in Claim 6, wherein the first bore is counterbored for accommodation at an inner end of the counterbore of the first valve seat.

8. A stop valve arrangement as claimed in Claim 7, wherein the counterbore is tapped towards its outer end to receive a screw in bush to slidably support a shaft extending from the opposite side of the valve head to that of the spindle.

9. A stop valve as claimed in Claim 8, wherein the shaft has a threaded terminal end on to which is screwed a manually operable push-pull button located externally of the valve body.

10. A stop valve arrangement as claimed in Claim 9, wherein the bush is counterbored to receive an internally threaded connection stem of the push-pull button.

11. A stop valve arrangement as claimed in any one of Claims 6 to 10, wherein the second bore is counterbored for accommodation at the inner end of the counter bore of the second valve seat, with a closure plug being screwed into a tapped outer end of this bore.

12. A stop valve arrangement as claimed in any one of Claims 3 to 11, wherein the second valve member is provided with a spring.

13. A stop valve arrangement as claimed in Claim 12, wherein the spring is a coil compression spring.

14. A stop valve arrangement as claimed in any preceding Claim, wherein the port of the valve body is linear.

15. A stop valve arrangement as claimed in any one of Claims 1 to 13, wherein the port of the valve body is stepped.

16. A stop valve arrangement substantially as hereinbefore described with reference to the accompanying drawing.

17. A hydraulic circuit for a hydraulically powered, self-advancing mine roof support, comprising a mains, pressure line; a feed line to the support from the pressure line, and a stop valve arrangement as defined in any preceding claim.

18. A hydraulically powered, self-advancing, mine roof support incorporating a hydraulic circuit as defined in Claim 17.