Title of Invention

VALVE TO CONTROL A FLUID

Abstract

A valve to control a fluid, in particular to control a gas, is proposed comprising of a valve casing that receives an operating device for a magnet armature that is operated to move in an axial direction in the valve casing and is provided with a valve closing element at whose front side a sealing element (29) is located that works together with the valve seat (21) which is designed at a seat plate (26) in such a manner that a fluid stream can be controlled by venting holes (28) of the seat plate (26). The valve seat (21) is formed by an essentially circular inner shoulder (30) and an essentially circular outer shoulder (31) and the venting holes (28) are located between the inner shoulder (30) and the outer shoulder (31). (Figure 3).

Full Text

Valve to Control a Fluid Prior Art The invention emanates from a valve to control a fluid, particularly to control a gas, in accordance with the type defined in greater detail in the preamble of patent claim 1. This type of valve is established in practice and applicable for example, as a gas control valve in a fuel cell or also in a gas engine. The established valve comprises of a valve casing that can be designed to have several parts and in which an operating device for a magnet armature is located. The magnet armature can be driven axially in a correspondingly built receptacle of the valve casing, sleeve-shaped wherever applicable, and provided with a valve closing element that works together with the valve seat in such a manner that a fluid flow can be controlled by at least one venting hole that is located in a seat plate and leads to the venting side of the valve. An elastic seal that serves to control a gas is located at the front side of the valve closing element that faces the valve seat and is made from an elastomer, PEEK or a similar material and abuts the valve seat when the valve closing element is closed. The elastic seal hereby lies essentially over the entire surface of the seat plate that faces the valve closing element. The basic problem in the case of gas valves is that the dry and gas-type medium to be controlled can cause heavy abrasion in the valve seat area i.e. in the sealing area, which could lead to changes in the functional characteristics of the valve and also to an unacceptably high leakage rate when the valve closing element is closed. A further problem in the case of the established valve described above is that leakages could occur in the valve seat area due to the clearance-conditional, tangential erection of the magnet armature. Due to high surface pressure, the tangential erection of the magnet armature could also be the reason in particular for high abrasion of the seal during valve operation. Furthermore sealing of the venting hole by a surface can result in setting effects that have a negative impact such as, for example, penetration of the seal in the venting hole and other disadvantageous changes in the venting hole area. Advantages of the Invention The valve in accordance with the invention to control a fluid, particularly to control a gas, with features according to the preamble of patent claim 1, in which the valve seat is created by an essentially circular, inner shoulder and an essentially circular outer shoulder and the venting holes are located between the inner and outer shoulders, has the advantage that the impermeability of the valve is guaranteed for its service life even during setting procedures or in the case of oblique positioning of the magnet armature and/or the valve closing element, since the sealing element does not lie across the full surface but essentially lies on the valve seat along circular lines when the valve closing element is closed. The geometry of the valve seat determines the impermeability of the valve. A gas valve with a valve seat that is designed in accordance with the invention, offers an optimised seating geometry which ensures high impermeability and permanent stability of the valve function during the valve's service life in all operating conditions. A valve seat, designed in accordance with the invention, that is easy to manufacture as well as cost-effective, in addition offers the advantage that an opening procedure of the magnet armature and of the valve closing element respectively is supported by the gas to be controlled since the same already flows below the sealing element upstream of the valve seat when the valve closing element is closed. Improved gas inflow is thus also present in the region of the valve seat in the valve according to the invention. As a result of the high impermeability of the valve seat that is essentially pre-determined by the seating geometry and present even in the case of low temperatures, there is a wide variety of materials that can be used for the sealing element as well as great latitude with regard to shape. The valve in accordance with the invention is meant particularly for mass stream regulation of gases such as hydrogen and natural gas and can, for example, be employed in a fuel cell or also in a gas engine. In the case of a specific embodiment of the valve in accordance with the invention, the shoulders at that side facing away from the venting holes each have a diagonally sloping outer flange. The outer flanges can each be designed as straight sloping surfaces i.e., as conical surfaces and in this case enclose a pointed angle with the front surface of the seal and of the sealing element respectively. The outer flanges can alternatively also have a curved cross-section, which can be provided with a consistent or even with a changing radius. In order to improve streaming behaviour of the gas that is controlled by means of the valve in accordance with the invention and in order to reduce abrasion of the sealing element, the shoulders at that side that faces the venting hole have an inner flange each that is preferably built with a curved cross-section and/or radius. It is, however, also conceivable that the inner flange can consist essentially of a conical surface that crosses over in a chamfer of the respective shoulder and/or is formed by this kind of chamfer. The front sides of the shoulders with which the sealing element comes into contact when the valve closing element is closed are, as a rule, curved. Alternatively it is, however, also conceivable that the shoulders each have a front side that is essentially parallel to the front side of the seal and consequently has a planar surface. The shoulders whose flanges are formed by conical surfaces and/or levels with an angle of inclination of, for example 10° or even formed by curved surfaces, ensures that the sealing element of the valve closing element always sits flat or linear on the valve seat thus achieving high impermeability. The shoulders can hereby be manufactured with cross-sections that are symmetric to one another or even with surfaces and/or curves having varying designs. The abovementioned seating geometry described can be manufactured to have a single level or several levels. The seating geometry can, for example, be manufactured in such a manner that the seat plate is machined using a form single-point cutting tool first after a rotary process and subsequently after a form grinding process. It is practical, particularly when the seating geometry is manufactured according to a form grinding process, to have grooves emerge during grinding that are located along the injection apertures with reference to the circular lines and that run concentric and in a non-radial fashion which favourably influences the valve's impermeability. Concentrically running grooves prevent penetration of the sealing element by the gas that is to be controlled, which could present a potential leakage risk during the course of the valve's service life, particularly in the case of grooves that run in a radial direction. Other advantages and beneficial designs of the invention according to the invention can be derived from the description, the drawing and the patent claims. Drawing Four exemplary embodiments of a valve according to the invention are illustrated in a schematic, simplified manner and are described in greater detail in the following description. Figure 1 illustrates a simplified longitudinal section through the first embodiment of a gas valve; Figure 2 is a magnified illustration of the area marked II in Figure 1; Figure 3 is a magnified illustration of the area marked III in Figure 2; Figure 4 illustrates that area of the gas valve according to Figure 1, shown in Figure 3 but, however, before using a fine grinding process; Figure 5 shows an alternative valve seat with adjacent sealing element; Figure 6 illustrates the valve seat geometry according to Figure 5 before using a fine grinding process; Figure 7 illustrates manufacture of the valve seat geometry presented in Figure 5; Figure 8 is a top view of a valve plate with the valve seat geometry illustrated in Figure 5; Figure 9 is a longitudinal section illustration of a third embodiment of a valve's valve seat of the type illustrated in Figure 1; and Figure 10 is a longitudinal section of a fourth embodiment of a valve's valve seat of the type illustrated in Figure 1 before using a fine grinding process. Description of the Exemplary Embodiments A gas valve is illustrated in Figure 1 that is designed for employment in a fuel cell or in a gas engine and serves to regulate gas flow of, for example, hydrogen, LPG (liquid petroleum gas) or CNG (compressed natural gas) from a supply side 11 to a venting side 12. The valve 10 has a multiple part casing 13 that accepts a magnetic coil 14 that encompasses a guide bush 15. An essentially tubular plug 16 is fixed in the guide bush 15. A spiral spring 17 that serves as a pre-loaded spring and that acts upon the magnet armature 18 is pushed into the plug 16. The magnet armature 18 moves longitudinally in the guide bush 15 during operation. The magnet armature 18 is essentially tubular and forms a valve closing element 20 at its side that faces away from the pre-loaded spring 17. The valve closing element 20 works together with a valve seat 21 that is illustrated in greater detail in Figures 2 to 4. Furthermore, the magnet armature 18 is provided with an internal space 22 that is connected to the supply side 11 of the valve 10 and from which radial venting bores 23 and an axial venting bore 24 branch off in the present exemplary embodiment. The radial venting bores 23 lead to a high-pressure chamber 25 that is bordered radially by the guide bush 15. The axial venting bore 24 leads to the front side of the magnet armature 18. As can be gathered from Figures 2 to 4 in particular, the valve seat 21 is designed at a base plate 26 of an essentially cup-shaped component 27t this base plate 26 being designed as a seat plate. The base plate 26 is provided with a plurality of venting holes 28 that are designed as nozzles and that connect the high-pressure chamber 25 to the venting side 12 of the valve 10 when the valve closing element and magnet armature 18 respectively are open. The nozzles and/or holes 28 are located along a circular line and are covered by a sealing element 29 when the valve closing element and magnet armature 18 respectively are closed. The sealing element 29 can be made from a synthetic material such as elastomer, PEEK or something similar and is fixed at the front side of the magnet armature 18 and lies on the valve seat 21. The sealing element 29 can be provided with a coating of, for example, PTFE, to increase diagonal manoeuvrability. The valve seat 21 is formed by a circular inner shoulder 30 and a circular outer shoulder 31, whereby the venting holes 28 are located between the inner shoulder 30 and the outer shoulder 31. Shoulders 30 and 31 have an outer flange 32 and 33 respectively at their sides that faces away from the venting holes 28 that is designed as a straight sloping conical surface and encloses an angle of approximately 10° with the front surface of the sealing element 29. The outer flanges 32 and 33 cross over in each case into an essentially bulging elevation 34 and 35 respectively, which form an arched strike surface of the respective shoulder 30 and 31. At that side that faces the nozzles 28, the arched front surfaces 34 and 35 each cross over again into a curved, diagonally sloping inner flange 36 and 37 respectively having a radius of, for example, 0.1 mm. In order to produce the valve seat 21 geometry illustrated in Figure 3 in particular, a multi-stage process is used at present in which the general contour illustrated in Figure 4 is first manufactured-using a rotary process and then the area in Figure 4 that is provided reference number 38 is worn down using a fine grinding process so that the surface contour of the valve seat 21 illustrated in Figure 3 is created in which the inner shoulder 30 has a cross-section that is designed to exhibit mirror symmetry with the cross-section of the outer shoulder 31. After the fine grinding process, the valve seat exhibits grooves that are located essentially concentric to shoulders 30 and 31. An alternative embodiment of valve seat geometry in a gas valve of the type illustrated in Figure 1 and designed in accordance with the invention is illustrated in Figures 5 to 8. Corresponding to the exemplary embodiment according to Figures 2 to 4, the exemplary embodiment illustrated in Figures 5 to 8 has a valve seat 21' that is created by a circular inner shoulder 30' and a circular outer shoulder 31'. The shoulders 30' and 31' each have an outer flange 32' and 33' respectively at that side that faces away from the venting holes 28. The outer flange 32' and/or 33' is designed as a straight sloping conical surface and encloses an angle of approximately 10° together with the front surface of a sealing element 29 that is made from elastomer. The outer flanges 32' and 33' each cross over to bulging elevation 34' and 35' respectively, which form the front surface of the respective shoulder 30' and/or 31' and come into contact with the sealing element 29. The bulging elevations 34' and 35' cross over through a radius at that side that faces the venting holes 28 into a steeply sloping inner flange 36' and/or 37' that has a mild concavity. Manufacture of the valve seat 21 illustrated in detail in Figure 5, takes place similarly in two stages and in fact in such a manner that the a general contour is first produced at the seat plate that is designed with an area that is furnished with reference sign 38' in Figure 6 and that is worn down by means of a subsequent fine grinding process. For this purpose, as can be derived from Figure 7, a form single-point cutting tool 44 is used, for example, that is placed on the general contour and wears down the area 38' shown in Figure 6 by a rotary movement. The axis of the form single-point cutting tool 44 creates an axis 45 of circular shoulders 30' and 31' here too whereby grooves 46 that run concentric to shoulders 30' and 31'arise at the valve seat 21' due to the form grinding process. Figure 9 illustrates another embodiment of a valve seat 21" pertaining to a gas -valve of the type illustrated in greater detail in Figure 1. The valve seat 21" by and large corresponds to the valve seat in Figure 5 but differentiates itself in that it has outer flanges 32" and 33" respectively at both shoulders 30" and 31", these flanges exhibiting a curved cross-section i.e., a radius. Figure 10 illustrates yet another embodiment of a valve's valve seat of the type illustrated in Figure 1 before fine metal finishing. This valve seat is similarly created by an inner shoulder 30"' and an outer shoulder 31'" each of which have diagonally sloping flanges 32"' and 33'" at that side that faces away from nozzles 28. Shoulders 30'" and 31'" at that side that faces nozzles 28 are each provided with diagonally sloping inner flanges 36'" and 37'" respectively that are designed as conical surfaces. Area 38'" that is triangular in cross-section is worn down during the fine metal finishing at the front side of shoulders 30"' and 31"' respectively so that a front surface 34"' and 35'" respectively emerges that is essentially parallel to the front side of the sealing element that is not represented in Figure 10. Claims 1. Valve to control a fluid, in particular to control a gas, comprising of a valve casing (13) that receives an operating device (14) for a magnet armature (18), that moves axially in the valve casing (13) during operation and that is provided with a valve closing element (20) at whose front side a sealing element (29) is located which works together with valve seat (21, 21', 21", 21"') designed at a seat plate (26) in such a manner that a fluid stream can be controlled by venting holes (28) of the seat plate (26), characterised in that the valve seat (21, 21', 21", 21'") is formed by an essentially circular inner shoulder (30, 30'. 30", 30'") and an essentially circular outer shoulder (31, 31', 31", 31"') and that the valve holes are located between the inner shoulders (30, 30', 30", 30"') and the outer shoulders (31, 31', 31", 31"'). 2. Valve according to Claim 1, characterised in that the shoulders (30, 30', 30", 30"', 31, 31', 31', 31'") each have a diagonal sloping outer flange (32, 32', 32", 32"', 33, 33\ 33", 33") at that side that faces away from the venting holes (28). 3. Valve according to Claim 2, characterised in that the diagonal sloping outer flanges (32, 32', 32", 32'", 33, 33', 33", 33") are each designed as conical surfaces. 4. Valve according to Claim 2, characterised in that the diagonal sloping outer flanges (32", 33") are each designed with a curved cross- section. 5. Valve according to Claim 1, characterised in that the shoulders (30, 30\ 30", 31, 31', 31") each have a curved front surface (34, 34', 34", 35, 35', 35"). 6. Valve according to Claim 1, characterised in that, the shoulders (30'", 31'") each have a front surface (34"', 35'") that are essentially parallel to the front surface of the seal (29). 7. Valve according to Claim 1, characterised in that the shoulders (30, 30'", 31, 31"') each have a diagonal sloping inner flange (34, 34'", 35, 35'") at that side that faces the venting holes (28) that is preferably provided with a radius. 8. Valve according to Claim 1, characterised in that the inner shoulder (30, 30', 30"') has a cross-section that is designed to essentially exhibit mirror symmetry with the cross-section of the outer shoulder (31, 31', 31"). 9. Valve according to one of Claims 1 to 6, characterised in that the valve seat (21, 21', 21", 21'") is manufactured using a form machining process such as a rotary process, a grinding or an eroding process and has grooves (46) that are essentially located concentric to shoulders (30, 30', 30", 30"', 31, 31', 31", 31'").

Documents:

1509-CHENP-2006 AMENDED CLAIMS 13-01-2012.pdf

1509-CHENP-2006 AMENDED PAGES OF SPECIFICATION 13-01-2012.pdf

1509-CHENP-2006 EXAMINATION REPORT REPLY RECIEVED 13-01-2012.pdf

1509-CHENP-2006 CORRESPONDENCE OTHERS 25-02-2011.pdf

1509-CHENP-2006 CORRESPONDENCE PO.pdf

1509-CHENP-2006 FORM-18.pdf

1509-CHENP-2006 FORM-3 13-01-2012.pdf

1509-CHENP-2006 OTHER PATENT DOCUMENT 13-01-2012.pdf

1509-CHENP-2006 POWER OF ATTORNEY 13-01-2012.pdf

1509-chenp-2006-abstract.image.jpg

1509-chenp-2006-abstract.pdf

1509-chenp-2006-claims.pdf

1509-chenp-2006-correspondnece-others.pdf

1509-chenp-2006-description(complete).pdf

1509-chenp-2006-drawings.pdf

1509-chenp-2006-form 1.pdf

1509-chenp-2006-form 26.pdf

1509-chenp-2006-form 3.pdf

1509-chenp-2006-form 5.pdf

1509-chenp-2006-pct.pdf