TECHNICAL FIELD

[0001] This invention relates broadly to the field of mechanical valves, and more specifically to a flushing arrangement for a valve and a valve assembly including such a flushing arrangement.

BACKGROUND ART

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0003] Valves are well-known in the art and have been used since ancient times to regulate the movement of fluids in conduits. Valves are found in virtually every industrial process, including water and sewage processing, mining, power generation, processing of oil, gas and petroleum, food manufacturing, chemical and plastic manufacturing and many other fields. In processes involving the movement of abrasive or corrosive fluids, such as slurries, valves are required which removes the valve member or gate entirely from the path of the fluid flow to prevent abrasion of the valve member or gate. One such example is a knife gate valve.

[0004] Knife gate valves were originally designed for the paper and pulp industries, as the design offered improved lifespan in slurry applications compared to gate, diaphragm and ball valves. Most problems related with knife gate valves are due to seat failure - a slurry by its nature is typically highly abrasive and in some process plants, slurry contains solid particles that can be as large as 25mm in diameter. Slurry is generally pumped in a pipeline at velocity, e.g. 3.5m/s, to avoid settling of particles in the pipeline. The combination of such suspended solids and the slurry pumped at velocity generally means that pipeline equipment, such as valves, are constantly exposed to wear. As valves are typically used to control flow of a slurry, an increases of slurry velocity during the closing stroke of the valve as the area available for flow decreases, increases the velocity of the slurry, thus causing excessive wear during the opening and closing of valves.

[0005] Conventional thinking in addressing this problem was to use materials with higher wear resistance in the parts that is exposed to wear, but these materials are typically expensive, as well as difficult and costly to machine. The use of a so-called deflector cone has also been used by many manufacturers to deflect the slurry away from the seating area of a valve. These defector cones have a conical shape and are generally installed on the upstream side of the valve. Although somewhat effective in some instances, these defector cones often cause turbulence and localized wear in a different part of the valve or downstream pipeline.

[0006] Another conventional approach to addressing the problem of knife gate wear, is to incorporate a valve body design that offers a full-bore design, wherein the internal diameter of the valve is the same as the inside diameter of the mating pipe. In this manner, no part of the valve interferes with the slurry's flow path and no valve parts collide with the slurry particles, which reduces wear. Such conventional knife gates use two rubber sleeves compressed together, with the gate having a sharp edge, i.e. like a 'knife' which slides between the two rubber sleeves from top to bottom until the flow path is fully obstructed and flow is prevented.

[0007] This sleeved type knife gate design is commonplace for most slurry applications; however, the design still has shortcomings. The sleeved type design normally consists of a single unitary valve body casting or two mirror castings bolted together, with two sleeves compressed together with compression flanges (some designs rely on the adjacent pipe flanges to compress the sleeves) . A conventional valve will also typically have a stem or yoke and an actuator for displacing the kni fe gate , e . g . a hand wheel , a pneumatic or hydraulic cylinder, an electromechanical actuator, etc .

[ 0008 ] One shortcoming with such conventional kni fe gate valves is seat failure , where the valve seat cannot stand up to the solid and large particles that is forced into the seat during the closing stroke of the valve . Often a 'bedrock' is formed in slurry pipelines due to a combination of particle s i ze and lower velocities . The gate then has to ' cut ' through this bedrock or accretion layer o f particles which may cause damage the rubber seats . This also leads to the valve not being able to close fully, which may cause unscheduled operational downtime .

[ 0009 ] Many examples of conventional kni fe gate valves 'purge ' during the opening and closing stroke at the leading edge of the gate where the gate separate the sleeves - there is typically a small opening in front of the gate leading edge . Often particles lodge between the two sleeves in this resulting opening and cause a leak pathway . Consequential damage is caused by the slurry further eroding the seats and gate and often the body, as extreme velocities occur in these instances that may lead to premature valve failure .

[ 0010 ] A further shortcoming is that slurry build-up occurs in the body cavity over time and then causes valve failure . Every time the valve opens , a thin layer of slurry remains in the valve body cavity . Over a period of time , the slurry builds up to a stage where the body cavity is completely blocked . It is normal for a sleevetype kni fe gate valve to discharge some slurry during opening and closing cycles due to its inherent design . Such kni fe gate valve discharge can be controlled (not contained) with the use of an optional splash guard device , such as a splash bucket or splash plate . [ 0011 ] The splash plate typically bolts to the bottom of the valve housing with the use of an adapter plate . The splash plate is provided with ports to flush or drain away accumulated solids that may prevent full gate closure . Flush water can both enter and exit the clean-out area through the drain plate ports . These splash guard devices can be connected to an on-site piping system to provide a means of carrying the discharge away to a permanent drain or other collection point , however this i s expensive and often impractical to implement on a site .

[ 0012 ] Applicant has developed a knife gate valve arrangement in amelioration of many of the shortcomings of conventional kni fe gate valves . The present invention was conceived with the goal in mind of ameliorating flushing of such kni fe gate valves .

SUMMARY OF THE INVENTION

[ 0013 ] According to a first aspect of the invention there is provided a flushing arrangement for a kni fe gate valve , said flushing arrangement comprising : a fluid inlet comprising a check valve and a tee or wye fitting having first and second fluid outlets , the first outlet arrangeable in fluid communication with an input port of a flushing circuit of the kni fe gate valve ; a normally open hydraulic diaphragm valve arranged in fluid communication with an output port of said flushing circuit of the kni fe gate valve ; a needle valve supplied with fluid from the second fluid outlet of the tee or wye fitting and configured to actuate said diaphragm valve into a closed position when supplied by such second fluid outlet ; and a timer valve arranged in fluid communication with the diaphragm valve and configured to vent the second fluid supply from the needle valve at selectable intervals so that the diaphragm valve is actuated into an open position; wherein a mains fluid supply is connectable to the fluid inlet to flush the flushing circuit of the knife gate valve automatically at selectable intervals.

[0014] In an embodiment, the fluid inlet comprises an isolation valve for isolating the check valve and tee or wye fitting.

[0015] In an embodiment, the fluid inlet comprises a Y-strainer to facilitate the removal of impurities from the flushing arrangement .

[0016] In an embodiment, the fluid inlet comprises a pressure reducer to reduce a pressure of fluid received from the mains fluid supply .

[0017] In an embodiment, the needle valve is configured to actuate the diaphragm valve into a closed position by supplying an actuator chamber of said diaphragm valve with fluid.

[0018] In an embodiment, the timer valve is configured to vent the second fluid supply from the needle valve by venting an actuator chamber of said diaphragm valve.

[0019] In an embodiment, the timer valve vents the second fluid supply from the diaphragm valve to a sump or collection reservoir.

[0020] In an embodiment, an outlet of the diaphragm valve is arranged in fluid communication with a sump or collection reservoir for collecting fluid from the flushing circuit of the knife gate valve .

[0021] In an embodiment, the timer valve comprises a battery- operated timer valve. [ 0022 ] In an embodiment , the flushing arrangement comprises an isolation valve for isolating the diaphragm valve from the flushing circuit of the kni fe gate valve .

[ 0023 ] In an embodiment , the flushing arrangement is housed in an enclosure mountable proximate the kni fe gate valve .

[ 0024 ] According to a second aspect of the invention there is provided a kni fe gate valve assembly comprising : a kni fe gate valve member ; a valve body defining a pipeline coupling whereby the body is operatively arrangeable in line with a pipeline , at least two actuator supports configured to support actuators on opposite sides of the pipeline coupling, a gate guide with seal assembly for guiding the kni fe gate valve member between a closed position ( in which the valve member obstructs fluid flow through the pipeline coupling) and an open position ( in which the pipeline coupling is unobstructed to fluid flow) , said body further defining a flushing circuit for operative inj ection of flushing fluid about at least a portion of the gate guide to minimise accumulation of particles proximate the valve member when actuated between the open and closed positions ; at least two actuators each supported by an actuator support and configured to selectively actuate the valve member between the open and closed positions ; and a flushing arrangement comprising : i . a fluid inlet comprising a check valve and a tee or wye fitting having first and second fluid outlets , the first outlet arranged in fluid communication with an input port of the flushing circuit of the kni fe gate valve ; ii . a normally open hydraulic diaphragm valve arranged in fluid communication with an output port of said flushing circuit of the kni fe gate valve ; iii . a needle valve supplied with fluid from the second fluid outlet of the tee or wye fitting and configured to actuate said diaphragm valve into a closed position when supplied by such second fluid outlet; and iv. a timer valve arranged in fluid communication with the diaphragm valve and configured to vent the second fluid supply from the needle valve at selectable intervals so that the diaphragm valve is actuated into an open position; wherein a mains fluid supply is connected to the fluid inlet to flush the flushing circuit of the knife gate valve automatically at selectable intervals.

[0025] In an embodiment, the fluid inlet comprises an isolation valve for isolating the check valve and tee or wye fitting.

[0026] In an embodiment, the fluid inlet comprises a Y-strainer to facilitate the removal of impurities from the flushing arrangement .

[0027] In an embodiment, the fluid inlet comprises a pressure reducer to reduce a pressure of fluid received from the mains fluid supply .

[0028] In an embodiment, the needle valve is configured to actuate the diaphragm valve into a closed position by supplying an actuator chamber of said diaphragm valve with fluid.

[0029] In an embodiment, the timer valve is configured to vent the second fluid supply from the needle valve by venting an actuator chamber of said diaphragm valve.

[0030] In an embodiment, the timer valve comprises a battery- operated timer valve.

[0031] In an embodiment, the timer valve vents the second fluid supply from the diaphragm valve to a sump or collection reservoir. [ 0032 ] In an embodiment , an outlet of the diaphragm valve is arranged in fluid communication with a sump or collection reservoir for collecting fluid from the flushing circuit of the kni fe gate valve .

[ 0033 ] In an embodiment , the flushing arrangement comprises an isolation valve for isolating the diaphragm valve from the flushing circuit of the kni fe gate valve .

[ 0034 ] In an embodiment , the flushing arrangement is housed in an enclosure mounted proximate the kni fe gate valve .

[ 0035 ] According to a third aspect of the invention there is provided a valve assembly comprising : a valve having a flushing circuit ; and a flushing arrangement in accordance with the first aspect of the invention, said arrangement configurable to flush the flushing circuit of the valve automatically at selectable intervals .

[ 0036 ] According to a further aspect of the invention there is provided a flushing arrangement for a kni fe gate valve and a kni fe gate valve assembly, substantially as herein described and/or illustrated .

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be made with reference to the accompanying drawings in which :

Figure 1 is a diagrammatic overview representation of a flushing arrangement for a kni fe gate valve , in accordance with aspects of the present invention; Figure 2 is a diagrammatic front-sectional view representation of one embodiment of a kni fe gate valve useable with the flushing arrangement of Figure 1 ;

Figure 3 is diagrammatic side-sectional representation of the kni fe gate valve of Figure 2 ;

Figure 4 is a diagrammatic perspective-view representation of the kni fe gate valve of Figure 2 ;

Figure 5 is a front perspective-view diagrammatic representation of one embodiment of a kni fe gate valve arrangement in accordance with aspects of the invention, showing the valve member in the open position;

Figure 6 is a front perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 5 , showing the valve member in the closed position;

Figure 7 is a top perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 5 , showing the valve member in the open position;

Figure 8 is a top perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 7 , showing the valve member in the closed position;

Figure 9 is a bottom perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 5 , showing the valve member in the closed position;

Figure 10 is a top perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 8 , showing the valve member in the open position; Figure 11 is a sectional perspective-view diagrammatic representation of the kni fe gate valve arrangement o f Figure 5 , showing the valve member in the closed position;

Figure 12 is a sectional perspective-view diagrammatic representation of the kni fe gate valve arrangement of Figure 11 , showing the valve member in the open position;

Figure 13 is a perspective-view diagrammatic representation of one example of a gland of the kni fe gate valve arrangement of Figure 5 ; and

Figure 14 is a closer view of a side aspect of the gland of the gland of Figure 13 .

DETAILED DESCRIPTION OF EMBODIMENTS

[ 0037 ] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof . This description is included solely for the purposes of exempli fying the present invention to the skilled addressee . It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above .

[ 0038 ] In the figures , incorporated to illustrate features of the example embodiment or embodiments , like reference numerals are used to identi fy like parts throughout . Additionally, features , mechanisms and aspects well-known and understood in the art will not be described in detail , as such features , mechanisms and aspects will be within the understanding of the skilled addressee .

[ 0039 ] Broadly, the present invention provides for a flushing arrangement 10 for valve , such as a kni fe gate valve 8 , as well as kni fe gate valve assembly comprising such a flushing arrangement 10 installed with a kni fe gate valve 8 .

[ 0040 ] With conventional valve flushing arrangements , fluid such as water is drawn-of f a main water ring, and the valve is either flushed by means of opening a ball valve manually or by opening a 2-way solenoid valve electrically . Electric solenoid valves require an external energy supply to operate , which can make them expensive to install and operate , typically in remote locations where electricity supply is in scarce supply . Operators are not always disciplined and it is not always practical to flush valves manually, as many sites have a large number of valves . As a result , the practice of flushing valves gets neglected, and build-up occurs which leads to valve failure over time . The present invention seeks to address this shortcoming with conventional valve flushing practices .

[ 0041 ] With reference now to the accompanying figures , there is shown one broad embodiment of a flushing arrangement 10 for a kni fe gate valve 8 . The flushing arrangement 10 generally comprises a fluid inlet 12 which comprises a check valve 14 and a tee ( T ) or wye (Y) fitting having first and second fluid outlets 18 and 20 , as shown . The check valve 14 is to regulate fluid flow in one direction only and to prevent backflow through the fluid inlet 12 . Typically, the first outlet 18 is arrangeable in fluid communication with an input port 22 of a flushing circuit 54 of the kni fe gate valve 8 .

[ 0042 ] In the exempli fied embodiment , the fluid inlet 12 also comprises an isolation valve 34 for isolating the check valve 14 and tee or wye fitting 16 for maintenance purposes . In this embodiment , the fluid inlet 12 also comprises a Y-strainer 36 to facilitate the removal of impurities , such as debris and unwanted particles , from the flushing arrangement 10 . The fluid inlet 12 further comprises a pressure reducer 38 in order to reduce a pressure of fluid received from a mains fluid supply 32 , such as a water main supply, or the like . [ 0043 ] Flushing arrangement 10 also includes a normally open hydraulic diaphragm valve 24 which is arranged in f luid communication with an output port 26 of the flushing circuit 54 of the kni fe gate valve 8 , as shown . An outlet of the diaphragm valve 24 is typically arranged in fluid communication with a sump or collection reservoir (not shown) for collecting fluid from the flushing circuit 54 of the kni fe gate valve 8 . As known in the art of diaphragm valves , the diaphragm valve 24 generally comprises an actuator chamber which is suppliable with fluid, such as liquid, in order to open or close said valve .

[ 0044 ] Flushing arrangement 10 also includes a needle valve 28 which is supplied with fluid from the second fluid outlet 20 of the tee or wye fitting 16 , as shown . In one embodiment , the needle valve 28 is configured to actuate the diaphragm valve 24 into a closed position by supplying an actuator chamber of said diaphragm valve 24 with fluid . The needle valve 28 is also typically configured to actuate the normally open diaphragm valve 24 into a closed position when a timer valve 30 , as described below, is closed and the needle valve 28 is supplied by such second fluid outlet 20 , typically into an actuator chamber of the diaphragm valve 24 . When the timer valve 30 is open, the needle valve 28 will restrict flow into an actuator chamber of the diaphragm valve 24 so that , when the timer valve 30 opens , the outflow of fluid from an actuator chamber is greater than the inflow ( from the second fluid outlet 20 of the tee or wye fitting 16 ) to the actuator chamber of the diaphragm valve 24 , thereby allowing the diaphragm valve 24 to open . When the timer valve 30 closes again, the fluid from the second fluid outlet 20 , via the needle valve 28 , will accumulate in the actuator chamber of the diaphragm valve 24 , resulting in the normally-open diaphragm valve 24 closing .

[ 0045 ] Finally, flushing arrangement 10 further includes the timer valve 30 which is arranged in fluid communication with the diaphragm valve 24 and which is configured to vent the second fluid supply 20 from the needle valve 28 at selectable intervals so that the diaphragm valve 24 is actuated into an open position, as described above . In such a manner, the mains f luid supply 32 is connectable to the fluid inlet 12 to flush the flushing circuit 54 of the kni fe gate valve 8 automatically at selectable intervals .

[ 0046 ] In a typical embodiment , the timer valve 30 comprises a battery-operated timer valve . As with the outlet of the diaphragm valve 24 , in one embodiment the timer valve 30 vents the second fluid supply 20 from the diaphragm valve 24 to a sump or collection reservoir (not shown) . In one embodiment , the flushing arrangement 10 also comprises a further isolation valve 34 for isolating the diaphragm valve 24 from the flushing circuit 54 of the kni fe gate valve 8 for maintenance purposes .

[ 0047 ] Applicant believes it particularly advantageous that the present invention provides for flushing arrangement 10 configured to independently and automatically flush a flushing circuit i f a valve to prevent build-up of slurry and solid particles in the valve body cavity, thereby promoting valve service li fe and valve seat longevity . Arrangement 10 does not require site power or manual input to flush and find particular application in replacing conventional inef ficient valve flushing systems . Arrangement 10 does not require manual input to flush a valve , thereby saving time , ef fort and money . Arrangement 10 is also able to flush valves automatically according to a selectable schedule , thereby replacing mundane routine tasks that are often neglected with potentially catastrophic consequences .

[ 0048 ] The skilled addressee is to appreciate that the present invention includes a kni fe gate valve assembly comprising a kni fe gate valve member 42 and a valve body 44 defining a pipeline coupling 46 whereby the body 44 is operatively arrangeable in line with a pipeline . Such an assembly also includes at least two actuator supports 48 configured to support actuators 56 on opposite sides of the pipeline coupling 46 , as well as a gate guide 50 with seal assembly 52 for guiding the kni fe gate valve member 42 between a closed position ( in which the valve member 42 obstructs fluid flow through the pipeline coupling 46 ) and an open position ( in which the pipeline coupling 46 is unobstructed to fluid flow) .

[ 0049 ] The body 44 further defines a flushing circuit 54 for operative inj ection of flushing fluid about at least a portion of the gate guide 50 to minimise accumulation of particles proximate the valve member 42 when actuated between the open and closed positions . The valve assembly further includes at least two actuators 56 each supported by an actuator support 48 and configured to selectively actuate the valve member 42 between the open and closed positions .

[ 0050 ] Importantly, the assembly also includes the flushing arrangement 10 , as described above , wherein a mains fluid supply 32 is connected to the fluid inlet 12 to flush the flushing circuit 54 of the kni fe gate valve 8 automatically at selectable intervals . In one embodiment , the flushing arrangement 10 is housed in an enclosure 40 mountable proximate the kni fe gate valve 8 .

[ 0051 ] With reference now to Figure 5 to 14 of the accompanying figures , there is shown a further embodiment of a kni fe gate valve arrangement 110 that finds particular application with the flushing arrangement 10 , as described above . In the exempli fied embodiment , the valve arrangement 110 generally comprises a kni fe gate valve member 112 , a valve body 114 and actuators 126 .

[ 0052 ] The valve body 114 defines a pipeline coupling 116 whereby the body 114 is operatively arrangeable in line with a pipeline (not shown) , as is known in the art . The body 114 also defines at least two actuator supports 118 which is configured to generally support actuators 126 on opposite sides of the pipeline coupling 116 , as shown . [ 0053 ] The body 114 further broadly defines a gate guide 120 with some manner of seal assembly 122 for guiding the kni fe gate valve member 112 between a closed position ( in which the valve member 112 obstructs fluid flow through the pipeline coupling 116 ) and an open position ( in which the pipeline coupling 116 is unobstructed to fluid flow) .

[ 0054 ] The body 114 further generally defines a flushing circuit 124 for operative inj ection of flushing fluid about at least a portion of the gate guide 120 , described in more detail below, in order to minimise accumulation o f particles proximate the valve member 112 when actuated between the open and closed positions .

[ 0055 ] The valve arrangement 10 also generally includes at least two actuators 126 that are each supported by an actuator support 118 and are configured to selectively actuate the valve member 112 in unison between the open and closed positions .

[ 0056 ] Importantly, the gate guide 120 is generally configured such that a direction of travel of the valve member 112 when actuated into the open position is substantially along the direction of gravity . Similarly, the gate guide 120 is configured such that a direction of travel of the valve member 112 when actuated into the closed position is substantially against the direction of gravity . The skilled addressee will appreciate that the direction of gravity is towards the centre of the earth, i . e . downwards .

[ 0057 ] In particular, and in light of the problems experienced with accretion of particles due to gravity when pumping slurry in a pipeline , the valve arrangement 110 is generally installed such that the valve member 112 opens downwards , as shown in the accompanying figures . In this manner, closing the valve member 112 occurs from a bottom part of the pipeline ( or more speci fically, the conduit l 30 of the pipeline coupling 116 , as described below) , so that particles settling-out of a slurry due to the influence of gravity is displaced or pushed out of the way from the bottom of the pipeline as the valve member 112 closes, rather than the valve member 12 closing onto such particles, as per the conventional designs.

[0058] The knife gate valve member 112 is typically actuated into or out of the pipeline coupling 116 and transverse to the flow of fluid within the pipeline to change between the closed or open positions, respectively. Typically, the valve member 112 comprises a plate-like structure, as shown, configured to obstruct the flow of fluid through the pipeline when actuated into the closed position.

[0059] The valve body 114 may comprise a unitary structure, or it may be formed from the combination of different parts, depending on requirements, and as known in the art of valve manufacture.

[0060] In the present example, the pipeline coupling 116 comprises a flange 128 with fastener apertures for coupling with a similar pipeline flange, typically via nut and bolt fasteners, or the like. As shown, the pipeline coupling 116 comprises two pipeline flanges 128, one at each end, for arranging the valve body 114 in line with a pipeline, with a conduit 130 between said flanges 128 defining part of the gate guide 120.

[0061] In this embodiment, the gate guide 120 comprises a channel 132 defined transversely through the conduit 130 of the pipeline coupling 116 for guiding the valve member 112, as well as legs 134 projecting from the pipeline coupling 116 and configured to guide the valve member 112 within said channel 132.

[0062] The gate guide 120 also includes a foraminous partition or screen 136, such as a metal mesh, which is arranged between the legs 134 to allow visual inspection of the valve member 114 whilst preventing physical access thereto, i.e. prevention of possible pinch points for safety. To this end, the valve member 112 also includes a visual indicator 138 which is configured to facilitate visual inspection of the position the valve member 112 is in, e . g . the indicator 138 is typically a bright and easily-recognisable colour, or the like .

[ 0063 ] The seal assembly 122 typically includes at least one seal 140 arranged within the channel 132 to minimise fluid escaping from the pipeline when the valve member 112 is actuated between the open and closed positions , i . e . rubber sleeves forming seals , or similar seals well-known in the art . The seal assembly 122 further typically includes a gland 142 arranged about the valve member 112 at an interface between the pipeline coupling 116 and the atmosphere , where the valve member 112 enters the valve body 114 , to minimise fluid escaping from the pipeline . The gland 142 is typically held in place via suitable retaining plates (not shown) , or the like , as is known in the art .

[ 0064 ] In the example shown in Figures 13 and 14 , the gland 142 consists of two mirrored halves ( to facilitate easy replacement without requiring removal of the valve gate member 112 ) . The halves of the gland 142 combine to form a U-shaped groove 156 operatively surrounding the valve member 112 with outside dimensions configured so that the valve member 112 fits snugly between the halves . The gland is typically manufactured from ultra-high molecular weight general polyethylene (UHMWPE ) .

[ 0065 ] The gland 142 also typically includes packing apertures 154 on either side , as shown, that marry-up with similar apertures in the body 114 . Such packing apertures 154 are generally used to pack the gland 142 or groove 156 with, for example , packing fibres , such as polytetrafluoroethylene ( PTFE ) or Teflon™ fibre , which, when compressed, forms a seal around the valve member 112 . Each halve of the gland 142 also includes a separator 152 to ensure that , when more packing fibre is forced into the groove 156 , that suf ficient pressure is created on a side of the valve member . Without thi s separator 152 , the packing fibres will naturally compact against the larger surface of the valve member, thus leaving a potential leak path on the side thereof . The gland 142 is generally re-packable (via the apertures on the side of the valve body) in line under full line pressure and does not require the line to be drained or depressurised, allowing maintenance while the valve arrangement 110 is in service .

[ 0066 ] In general , separator 152 is 1mm short of the face of the groove , as shown . This is so that the packing fibres from both grooves 156 is able to meet and marry-up before they make contact with the valve member . Enough pressure is generally generated by the packing fibres and the separators 152 to ensure each groove 156 forms a fluid-tight seal against the valve member 112 .

[ 0067 ] The flushing circuit 124 generally comprises at least one external flushing fluid inj ection aperture 144 defined in the body 114 , as well as a flushing cavity 146 defined by the body 114 proximate the channel 132 . In this manner, flushing fluid is inj ectable at a higher pressure than fluid pressure within the pipeline in order to pressurise the flushing cavity 146 to minimise accumulation of particles within the channel 132 when the valve member 112 is actuated between the open and closed positions . Such a flushing cavity typically forms complementarily with the valve member 112 guided in the channel 32 , as will be appreciated by the skilled addressee .

[ 0068 ] In the exempli fied embodiment , the actuator supports 118 comprise an upper support 148 and part of the legs 150 of the gate guide 120 , as shown, whereby an actuator 126 is supportable between this upper support 148 at one end and the upper part of the legs 150 at another . The actuators 126 are typically selected from a group consisting of a pneumatic actuator, a hydraulic actuator, and an electromechanical actuator, as is well-known in the art . [ 0069 ] Applicant believes is particularly advantageous that the present invention provides for valve arrangement 110 wherein the valve member closes from bottom upwards , thus not forcing solid particles into the seal assembly, sleeves or seating areas of the valve member, thereby causing damage that can lead to valve failure . The arrangement instead allows the valve member 112 to ' cut ' through any particle accretions or so-called 'bedrock' to close towards the top, thereby eliminating crushing of solids into the seat area .

[ 0070 ] Applicant believes it a further advantage that the arrangement 110 , particularly the arrangement of the opposite actuators 126 , provides a more compact design roughly only 66% of traditional valve design height and can be installed in smaller spaces . The unique actuator configuration further provides a balanced distribution of forces , further facilitated by the external gate guide legs 134 . The valve arrangement 110 is thus able to be installed in hori zontal and vertical positions without excessive stress/wear on the valve body and actuator components and seals . This also eliminates the need for costly valve supports , as the weight of the valve member is supported by the gate guide 120 . With the actuators 126 mounted on opposite sides of the valve body 112 and connected to the top of the valve body 112 with the actuator supports 118 forming a stabiliser plate , excessive vibration is also minimised, resulting in less wear on valve parts , such as actuator seals and bearings further preventing premature valve failure .

[ 0071 ] Importantly, the valve arrangement 10 includes the flushing circuit 124 which allows for sel f-cleaning operation . During opening or closing of the valve member 112 , the flushing cavity 146 can be pressurised with external water with a higher pressure than the pipeline in-line pressure , leading to a net inflow of water, thus preventing solid particles from a slurry getting lodged in undes ired areas . In addition, Applicant believes it particularly advantageous that the gland 142 is repackable with packing fibres without requiring removal of the gland 142 , which greatly facilitates maintenance of the valve arrangement 110 whilst minimising operational downtime.

[0072] In the example embodiments, well-known processes, well- known device structures, and well-known technologies are not described in detail, as such will be readily understood by the skilled addressee. Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features. Where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0073] It is to be appreciated that reference to "one example" or "an example" of the invention, or similar exemplary language (e.g., "such as") herein, is not made in an exclusive sense. Various substantially and specifically practical and useful exemplary embodiments of the claimed subject matter are described herein, textually and/or graphically, for carrying out the claimed subject matter. Accordingly, one example may exemplify certain aspects of the invention, whilst other aspects are exemplified in a different example. These examples are intended to assist the skilled person in performing the invention and are not intended to limit the overall scope of the invention in any way unless the context clearly indicates otherwise.

[0074] Variations (e.g. modifications and/or enhancements) of one or more embodiments described herein might become apparent to those of ordinary skill in the art upon reading this application. The inventor (s) expects skilled artisans to employ such variations as appropriate, and the inventor (s) intends for the claimed subject matter to be practiced other than as specifically described herein. [0075] The use of the terms "a", "an", "said", "the", and/or similar referents in the context of describing various embodiments (especially in the context of the claimed subject matter) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising, " "having, " "including, " and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. No language in the specification should be construed as indicating any non-claimed subject matter as essential to the practice of the claimed subject matter.

[0076] Spatially relative terms, such as "inner, " "outer, " "beneath, " "below, " "lower, " "above, " "upper, " and the like, may be used herein for ease of description to describe one element or feature's relationship to another element (s) or feature (s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.