AU2003240404A1 - Pressure and flow control valve - Google Patents

Abstract

A valve (1) serves to reduce pressure, particularly in nozzling devices. Said valve (1) is situated in the branch line (4) behind a switching valve (3) and before a nozzle (5) and comprises a high-pressure piston (10) and a low-pressure piston (18), which are equipped with axial and radial bores (11, 12 and 19, 20, 21) and disposed so that their piston heads (13, 22) abut against one another. By using a valve (1) of the aforementioned type, the pressure of the water supplied to the nozzling device or to the dust control device can be reduced, for example, from 100 to 20 or 30 bar while a regulation of quantity simultaneously ensues.

Description

VERIFICATION OF TRANSLATION Australian application No.: I, Thomas Ermer of Wordmaster Translations P/L, 19 High Road, Camberwell, 3124, am the translator of the document(s) attached and I state that the following is a true translation to the best of my knowledge and belief of International patent application PCT/DEO3/01391 (WO 03/093645 Al). Australian application for: Dated: 23.11.2004 S NAATIn No. 11738 THOMAS ERMER a TRANSLATOR Signature of translator:MAN-> ENGLISH Pressure and flow control valve The invention concerns a valve to control the pressure and the flow rate for consumers of pressurised fluid in underground mining and tunnel construction 5 with a valve housing accommodating the parts controlling the pressure and the quantity in its passing-through bore. To supply consumers from a single circuit with high pressure and with a correspondingly reduced pressure of the system by connecting a pressure 10 reducing device has been known for many years from the oil hydraulics and steam pressure technology. From "Einf0hrung in die Olhydraulik" [introduction in the oil hydraulics], Teubner Verlag [publisher], Stuttgart, 1984, p.137, a circuit diagram is known, where such a pressure reducing device is shown and explained. From "Hydrauliktrainer", a teaching and information book about hydraulics, copyright 15 1978 with G.L.Rexroth GmbH, it is explained on p.122, that the secondary pressure, i.e. the output pressure, is reduced with a pressure reducing valve. The secondary pressure is held constant independently from the input pressure as soon as it exceeds the set pressure. Therefore according to this state-of-the-art one can reduce the pressure in one section of a circuit to a value that is below 20 that of the pressure of the system. Similarly, steam pressure reducing valves have been known at least since 1925 ("Die Praxis des modernen Maschinenbaus", [Modern machine construction practice] Verlag C.U.Weller). It is explained on p.491, that the purpose of these known steam pressure reducing valves is to reduce, in certain cases, the normal pressure acting on the boiler 25 according to the consumer connected downstream. The valve used for this purpose at that time is explained in great detail in this state-of-the-art. In underground mining and tunnel construction, but also in other areas several consumers positioned in succession and a consumer with a different requirement are often connected to a supply line with the pressure generator. To satisfy the 30 various requirements, the supply line is charged with pressurised fluid in accordance with the consumer of the highest pressure. A correspondingly high pressure is frequently set also when a plurality of consumers is intended. In this case for the consumer, that requires a low pressure, the pressurised fluid is reduced, if possible and necessary, to the corresponding lower pressure (DE-A AMENDED PAGE 2 195 37 448 and DE-U-295 21 969). Pressure reducing valves of this kind, with which by means of a correspondingly constructed piston the pressure is so far reduced, that at least the pressure required by the consumer is approximately produced, are also known. At the same time it is difficult to accurately maintain 5 this reduced pressure over the period required, particularly when several consumers are connected to such a supply line. This is particularly the case in underground mining, when the pressurised water supplied at approx. 100 bar to the longwall face is required both for settling the dust behind the shield supports (in the crevasse) and in front of the shield supports (in the machine track). It is 10 known to provide the nozzles used in these fields for the excavating track and the extraction track regions with a correspondingly reduced water pressure, in fact at approx. 20 bar, however, so far it has not been possible to correctly supply these nozzles which also require a smaller quantity of water. At best this can be accomplished by that a special flow control valve is used, which is installed either 15 before or after the pressure regulation and is set according to the quantity. Apart from the fact, that a special valve is required for this, it is always a problem to adjust and balance these various valves so that the supply of the dust-settling nozzles is ensured with the correct water pressure and the correct quantity of water. US 3,196,016A and GB 606 623A also show so called seat valves, that 20 open and close openings with large cross-sections with tiny strokes. When the piston is lifted, the medium, the quantity of which cannot be controlled, flows in the direction of the low pressure section. Therefore the object of the invention is to provide a valve, particularly when 25 settling dust using nozzles in underground mining and tunnel construction, that provides water from the high-pressure supply line in a simple and reliable manner, that can be accurately adjusted with regard to both pressure and quantity to suit the requirements of the respective nozzles and has a simple in construction. 30 According to the invention this objective is achieved by the features of claim 1. With the aid of a valve constructed in this manner, it is possible to reduce the pressure of the high-pressure fluid in the supply line to such an extent, that the AMENDED PAGE 3 pr.essurised fluid with its original 100 bar will have, for example, a pressure of only 20 bar, and it is then supplied to the nozzle, while simultaneously the quantity is so adjusted that the performance of the nozzle will be at its optimum. At the same time the construction of the valve will ensure, that the values set 5 once can be reliably maintained for the entire application. Thus it is possible for the first time to provide devices and valves for equipment of this type in underground mining which are important and necessary for a reliable operation, that operate in the optimum range of the respective nozzle with regard both of pressure and quantity and consequently ensure a very effective settlement of the 10 dust. The pressurised medium, passing the high-pressure section, is adjusted for the quantity corresponding to the prevailing requirements by the throttle gap, while simultaneously by choosing the dimensions of the high-pressure and low pressure sections the required reduction of the pressure will also be accomplished. Thus a medium, that is optimally suitable to settle the dust in the 15 extracting region, can be provided past the high-pressure line with a single valve in the shortest possible manner. The construction of the valve is simple and it works reliably and accurately. The high-pressure section, having a smaller diameter, is first flown through by the pressurised fluid in the direction of flow, so that to be regulated with regard to its quantity and pressure. It is, however, also 20 conceivable to arrange the high-pressure section past the low-pressure section, but in this case special bores in the housing and additional efforts are required, not necessarily increasing the reliability of the valve. According to an appropriate development the invention provides that the high 25 pressure section and the low-pressure section with their radial bores with their closed piston heads are provided in the passing-through bore abutting against one another. Thus the pressurised fluid, i.e. the highly pressurised water, flows first through the high-pressure section with its axial and radial bores, and then conveyed through the throttle gap as well as regulated in its quantity. The 30 following low-pressure section ensures the corresponding reduction of the pressure, while the smaller high-pressure section is brought by the larger low pressure section to a position and held there, this position allowing the passing of only a very limited quantity of pressurised fluid, in fact through the throttle gap, so that a very uniform reduction of the quantity takes place. Thus it is ensured, that AMENDED PAGE 4 pressurised fluid with the optimum quantity is always available during the atomising process, while simultaneously the pressure reduction is also ensured by the differently dimensioned pistons and piston parts. Therefore during operation no measurings or additional equipment is necessary to ensure this 5 optimum quantity and pressure. At the same time the pistons, abutting with their piston heads against one another, influence one another in such a manner, that during the atomising process the pressure and quantity setting will be, as already mentioned, retained, whereas after the closing of the pilot valve, that, as a rule, is connected upstream, the pressure in the "system" decreases, so that the 10 pressure is correspondingly reduced and the smaller high-pressure section will occupy a position which, when switched on again, ensures that the region between the pressure reducing valve and the nozzle will be filled very quickly with pressurised fluid, so that the valve reaches the described controlling position very quickly and ensures that the pressurised fluid is held ready and is available 15 precisely with regard to the quantity and pressure which is necessary to settle the dust. It is understood, that the adjustment and control of the pressure and of the quantity is advantageous also for other purposes and can be correspondingly adjusted, by correspondingly harmonising the diameters and the throttle gap. 20 For the purpose of ensuring the passing over from the high-pressure section to the low-pressure section, the low-pressure section and the high-pressure section are arranged abutting against one another in the region of an extension of the passing-through bore the length of which corresponds to the displacement path of the low-pressure section and ensures the further flow of the pressurised fluid. 25 Thus the pressurised fluid flows through the high-pressure section and the throttle gap surrounding it first into the extension and therefrom exits through the radial bores of the low-pressure section into the axial bore and further via the line to the nozzle. In doing so, the low-pressure section can retract only so far, that the radial bores remain within the extension, so that the pressurised fluid can always 30 flow from there through the low-pressure section. To ensure the pressure reduction and a uniform further flowing of the pressurised fluid, it is additionally provided that the low-pressure section has more radial bores and consequently a larger cross-section of the openings than the high AMENDED PAGE 5 pressure section. This cross-section of the openings is particularly realised by the radial bores used, while the number of radial bores in the low-pressure section is twice that of the number in the high-pressure section. 5 For the quantities of pressurised fluid necessary to settle the dust, in fact for the reduced pressurised fluid, it is appropriate to construct the throttle gap cylindrically and permitting a stroke of 10 mm. This will ensure a very uniform escape of the pressurised fluid through the throttle gap, so that no detrimental turbulences or other problems will occur and an adequate length of the throttle 10 gap is always available, even when the smaller high-pressure piston or the high pressure section is correspondingly displaced in the bore of the housing. After reaching the pressure in the line, the low-pressure section should push the high-pressure section back in the passing-through bore so that the throttle gap 15 would remain effective. This is reliably achieved by that the larger step of the low pressure section is allocated to the low-pressure connection. Consequently a correspondingly large area will be available, ensuring that upon reaching the corresponding pressure the low-pressure section will correspondingly push back the high-pressure section. Due to its stepped construction the low-pressure 20 section itself can extend only as far as this is allowed by the two steps, by virtue of which a seizure of the high-pressure section is prevented. Rather do both pistons remain in a position, that makes a corresponding displacement in the direction or against the direction of the flow possible. 25 The reciprocating movement of the low-pressure section is further ensured by that the low-pressure section has a groove and an O-ring in the region of the larger step. This will ensure that the pressurised fluid cannot pass by the stepped piston or the low-pressure section, but presses the low-pressure section against the high-pressure section, so that to push this back into its passing-through bore. 30 For this purpose a seal with an O-ring, sealing the smaller step of the low pressure section, is embedded in the wall of the passing-through bore. Due to this the pressurised fluid cannot enter in this region either into the gap between the low-pressure section and the passing-through bore. AMENDED PAGE 6 When the valve opens, the low-pressure section can be driven by the high pressure section up to its stop. To ensure then a start at a pressure situation correspondingly achieved, it is provided that the low-pressure section has a starting radial bore or a groove at that impact end which is facing the low 5 pressure connection. The purpose of this starting radial bore is to ensure that the pressurised fluid can flow behind the impact end to ensure the outward movement of the low-pressure section. The even retraction and extension of the low-pressure section is further ensured 10 by providing a radially extending ventilation bore between the two hydraulic steps of the stepped piston. The low-pressure section draws air from the atmosphere through this ventilation bore when it is pushed back into its initial position by the high-pressure section. In the case of a reversed movement the air is pushed out into the atmosphere, so that the movement of the low-pressure section is kept 15 and secured at its optimum. To prevent the penetration of dust and of other materials that may cause problem into the ventilation bore and thus to prevent any damaging of the surface of the low-pressure section, the ventilation bore has a dust protective closure. It is 20 conceivable in this case that a rubber ring or a rubber hose is pushed on, that makes the flow-through of the air possible, while the drawing in of dust or similar components is prevented. The installation into a hydraulic line or a similar line is facilitated and a 25 replacement is made possible by that the valve housing with the passing through bore has on both sides a socket guide with a DN 10 plug connection. A plug connection with another dimension can, of course, also be used, but in the underground mining the DN 10 plug connection is the most frequently used one. By constructing the housing in this manner, the corresponding pressure reducing 30 valve can be simply installed and replaced, should this become necessary, for example when the reduction ratio has to be changed, as this is predetermined by the dimensions of the high-pressure section, low-pressure section and other details. A simple and purposeful construction of the corresponding pressure reducing valve is achieved when the socket guides can be screwed into the AMENDED PAGE 7 housing and are correspondingly sealed. Thus commercially available socket guides can be used, that can be simply screwed into the housing and so secured and sealed, that the valve can reliably function. In fact it could be useful to integrate the high-pressure section into the associated socket guide, i.e. to 5 provide there a corresponding special bore, because then no special components are necessary on this side of the housing. In that case both pistons can be simply inserted and the pressure reducing valve can be completed by assembling or screwing it together. As a rule, this is carried out above ground in the manufacturing workshop, but, if necessary, a checking or even repair can be 10 carried out also underground, since the construction of the valve is simple and understandable. For the consumers, that should be hydraulically tight, it is of advantage if in the region of the throttle gap an O-ring is provided, that can be passed by the radial 15 bores of the high-pressure section. This O-ring is embedded in the wall of the passing-through bore, for which purpose it has a groove and ensures that the pressurised fluid can penetrate into the extension through the throttle gap only when the high-pressure section passes the O-ring. 20 The invention is particularly characterised in that a pressure reducing and a volume controlling valve is produced, that can be particularly advantageously applied in underground mining and tunnel construction, where the required pressurised fluid, i.e. water as a rule, can be pumped into the longwall at a relatively high pressure. It will be reduced there on the respective consumer or 25 shortly before it to that extent and the quantity is so regulated, that it is discharged on the respective nozzle with the exact quantity and at a pressure that is appropriate to produce the mist, contributing and leading to the correct and reliable settling of the coal/rock dust. It is surprising and advantageous on this occasion, that with the aid of the single valve used not only is the pressure 30 reduced, for example, from 100 bar to 20 bar, but simultaneously the discharged quantity is also predetermined and adjusted to suit the respective nozzles to settle the dust. In the case of a 100:20 ratio the quantity can be set to 1-30 L, in this case preferably to approx. 5 L. In this manner a jet is produced on the discharge end of the nozzle, that results in a mist having droplets exactly with the AMENDED PAGE 8 sizes necessary to settle coal and rock dust. It is a further advantage, that such a valve can be simply installed in the existing line, preferably immediately after a pilot valve or possibly without such, so that the line is below 20 bar within a walling structure to the roof tip, so that optimal conditions are produced overall. 5 The pressure and quantity reducing valve can also be replaced and simply repaired, because it comprises few components, while the reciprocating components are so accommodated in the housing, that they cannot be damaged from the outside nor can they impair other devices, but particularly people. 10 Further details and advantages of the subject matter of the invention become apparent from the following description of the associated drawing, in which a preferred embodiment is illustrated with the necessary details and individual parts. They show in: 15 Fig.1 - a longitudinal section through a pressure reducing valve, Fig.2 - a schematic sketch regarding the installation of the pressure reducing valve used in mining, 20 Fig.3 - an enlarged illustration of the transition region of the two pistons, and Fig.4 - a side view of the pressure reducing valve. To reduce the pressure of a fluid the valve 1 shown in Fig.1 is provided. 25 According to Fig.2, in the application example shown there, this valve 1 is installed between a pilot valve 3 allocated to the supply line 2 and a nozzle 5 in a branch line 4, to ensure that the nozzle 5 is charged with water or another fluid the pressure of which is reduced and the quantity of which is set. 30 If, for example, the water flowing from the supply line 2 with a pressure of, for example 100 bar, is conveyed to the branch line 4 via the pilot valve 3, valve 1 will ensure that the pressurised water is reduced from 100 bar to 20 bar and flows to the nozzle 5 with a quantity of approx. 1 to 5 L. A dust nozzle adjusted in this manner provides unusually good results when used to settle the coal/rock dust. AMENDED PAGE This is ensured by reducing the pressure and adjusting the quantity of water to 1 30 L/min, preferably to 5 L/min. To enable the reduction of the pressure from 100 bar to 20 bar and to 5 correspondingly set the quantity, the valve 1 has a valve housing 8 with a bore 9 passing through longitudinally. In this passing-through bore 9 in the direction of flow 6 first a high-pressure section 10 is provided having an axial bore 11 in the form of a blind hole and radial bores 12. The piston head 13 abuts against the piston head 22 of the low-pressure section 18. The impact end 14 ensures that 10 the high-pressure section 10 can be displaced in the associated bore up to the impact end. The low-pressure section 18 also has an axial bore 19 in the form of a blind hole as well as a plurality of radial bores 20, 21. This low-pressure section 18 is 15 constructed as a stepped piston 24, wherein the larger step 25 has an impact end 23, while the smaller step 26 carries the piston head 22, that abuts against the piston head 13 of the high-pressure section 10. This head-to-head position takes place in an extension 30 of the passing-through bore 9, so that the pressurised fluid can flow from the radial bore 12 into the extension 30 and therefrom via the 20 radial bores 20, 21 into the low-pressure section 18. On this occasion the highly pressurised water is reduced purposefully by selecting the diameters from 100 bar to 20 bar, as mentioned above, while other reduction ratios are also feasible. When the inflow of the highly pressurised water is unblocked by the pilot valve 3 25 to the valve 1, the high-pressure section 10 is moved from its seat in the direction of the low-pressure connection 28, by doing so it correspondingly displaces the low-pressure section 18, until its impact end 23 abuts against the low-pressure connection 28 or the socket guide 50. The highly pressurised water then flows further to the nozzle 5 through the branch line 4, so that the corresponding 30 pressure is built up in the branch line 4, due to which a corresponding pressure occurs behind the impact end 23, ensuring that the low-pressure section 18 displaces now in the passing-through bore 9 the high-pressure section 10 against the direction of the flow, until the impact end 14 abuts against the stop 15 of the passing-through bore 9. The highly pressurised water can penetrate only through AMENDED PAGE 10 the radial bores 12 into the throttle gap 44, where the targeted reduction of the quantity is determined, so that to further stream via the extension 30, the radial bore 20, 21 into the axial bore 19 and thus in the direction of the nozzle 5, i.e. in the direction of flow 6. 5 The "opening" of the low-pressure section 18 is ensured by that on the impact end 23 a starting radial bore 34 or also corresponding grooves are provided, that ensure that the pressurised fluid will always reach the region of the impact end 23. The O-ring 33, provided in the groove 32, ensures that the pressurised fluid 10 cannot exit from the extension 30 along the smaller step 26. The groove 32 is formed in the wall 39 of the passing-through bore 9, whereby the O-ring 33 can then stroke along the smaller step 26 and ensure that the pressurised fluid cannot pass through. The larger step 25 also has a seal 40 with an O-ring 41 to prevent the passing of the pressurised fluid on the starting radial bore 34 along the larger 15 step 25. Between the larger step 25 and the smaller step 26 a ledge 35 is formed, and a ventilation bore 36 is provided there also, the purpose of which is to ensure that the movement of the low-pressure section 18 in the form of the stepped piston 24 20 will not be hindered. According to Fig.4 the ventilation bore 36 is so sealed by a dust protective closure, that foreign materials cannot reach the surfaces of the low-pressure section 18 through the ventilation bore 36. According to Fig.3 it is also feasible to provide the smaller high-pressure section 25 10 with'an O-ring 43, thus producing an enclosed and sealed system. The pressurised fluid can flow in the direction of the extension 30 via the throttle gap 44 only when this O-ring 43 is passed by the radial bores 12. On both sides of the housing 8 socket guides 46, 50 are provided to enable a 30 simple installation of the valve 1 in the branch line 4. These socket guides 46, 50 have threads 47, 51 and seals 48, 52, to achieve a rapid and reliable connection with the housing 8. By means of the plug connection 49, 53 a rapid and reliable connection with the hose ends of the branch line 4 is possible. Both Figs.1 and 4 illustrate this. AMENDED PAGE 11 In the embodiment shown the high-pressure section 10 has an axial bore 11 with a diameter of 5 mm and two radial bores 12 with a diameter of 2 mm. The larger low-pressure section 18 has an axial bore 19 with a diameter of 10-14 5 mm and four radial bores 20, 21 with a diameter of 2.7 mm. AMENDED PAGE

Claims (13)

1. A valve to control the pressure and the flow rate for consumers of pressurised fluid in underground mining and tunnel construction with a valve housing (8) 5 accommodating the parts (10, 18) controlling the pressure and the quantity in its passing-through bore (9), characterised in that in the passing-through bore (9) of the valve housing (8) a multipart piston (10, 18) having a high-pressure section (10) and a low-pressure section (18) is displaceably provided, the high-pressure section (10) of which has an axial bore (11) and a plurality of 10 radial bores (12) and is constructed in the passing-through bore (9) forming a throttle gap (44) that is predetermined with regard to its length and width and its low-pressure section (18) is provided in the direction of the flow (6) downstream to the high-pressure section (10) and has one axial bore (19) and a plurality of radial bores (20, 21) and is constructed as a stepped piston 15 (24).

2. A valve according to claim 1, characterised in that the high-pressure section (10) and the low-pressure section (18) with the radial bores (20, 21) with their closed piston heads (13, 22) are provided in the passing-through bore (9) 20 abutting against one another.

3. A valve according to claim 1 and claim 2, characterised in that the low pressure section (18) and the high-pressure section (10) are arranged abutting against one another in the region of an extension (30) of the passing 25 through bore (9), the length of which corresponds to the displacement path of the low-pressure section (18) and ensures the further flow of the pressurised fluid through the radial bores (20, 21).

4. A valve according to claim 1, characterised in that the low-pressure section 30 (18) has more radial bores (20, 21) and consequently a larger cross-section of the openings than the high-pressure section (10).

5. A valve according to claim 1, characterised in that the throttle gap (44) has a cylindrical construction and permits a stroke of 10 mm. AMENDED PAGE 13

6. A valve according to claim 1, characterised in that the larger step (25) of the low-pressure section (18) is allocated to the low-pressure connection (28).

7. A valve according to claim 6, characterised in that in the region of the larger 5 step (25) the low-pressure section (18) has a groove (40) and an O-ring (41).

8. A valve according to claim 1, characterised in that the low-pressure section (18) has a starting radial bore (34) or a groove at that impact end (23) which is facing the low-pressure connection (28). 10

9. A valve according to claim 1, characterised in that a radially extending ventilation bore (36) is provided between the two hydraulic steps (25, 26) of the stepped piston (24). 15

10. A valve according to claim 9, characterised in that the ventilation bore (36) has a dust protective closure (37).

11. A valve according to claim 1, characterised in that a seal (32) with O-ring (33) is embedded in the wall (39) of the passing-through bore (9), that seals the 20 smaller step (26) of the low-pressure section (18).

12. A valve according to claim 1, characterised in that the valve housing (8) with the passing through bore (9) has on both sides a socket guide (46, 50) with a DN 10 plug connection (49, 53). 25

13. A valve according to claim 1, characterised in that in the region of the throttle gap (44) an O-ring (43) is provided, that can be passed by the radial bores (12) of the high-pressure section. 30 AMENDED PAGE