Metering valve for a gas

Abstract

Metering valve (1) for a fuel cell arrangement, wherein the metering valve (1) comprises a magnetic armature (10, 14) which is received in a valve housing (34) and is actuated via a solenoid coil (42), wherein the magnetic armature (10, 14) is divided into a plunger armature (10) and a plate armature (14), each of which opens or closes a seat (4, 40), characterized in that the plunger armature (10) opens or closes a first seat (4) and the plate armature (14) opens or closes a second seat (40) which is provided in the valve housing (34), wherein the plate armature (14) is supported on a sleeve (16) which magnetically separates the magnetic core (12) from the plunger armature (10) and the plate armature (14), and wherein an interior of a housing (26) receiving the solenoid coil (42) is sealed by a sealing element (18) received on the sleeve (16), in particular It is sealed with an O-ring.

Description

Technical area

[0001] The present invention relates to a metering valve, in particular for a fluid in gaseous form, which is used in particular as an H2 metering valve for fuel cells. State of the art

[0002] US 7,687,171 B2 discloses a multi-stage ejector for a fuel cell system, comprising at least one ejector main body for supplying hydrogen. Each of the ejector bodies comprises a number of nozzles arranged one behind the other, leaving predetermined gaps whose diameters increase at the corresponding nozzles as viewed from an inlet side of the ejector main body to an outward side thereof. Furthermore, a number of sub-inlets are formed on an outer surface of the ejector main body, which is connected to the gap or gaps between the individual nozzles. The ejector main body is housed in a housing and includes a main inlet for receiving recirculated hydrogen. The multi-stage ejector improves system performance by increasing the amount of recirculated hydrogen.Furthermore, at least one safety valve is provided at an inlet position of the ejector to definitively prevent the backflow of recirculated hydrogen gas. At least one heating device is provided extending around the ejector to improve cold-start capability.

[0003] US 8 999 593 B2 relates to an ejector for a fuel cell. The ejector is used in a fuel cell and comprises an ejector main body with an inlet port, an outlet port, a suction port, and a port for an oxidizing gas. Furthermore, three chambers are provided in the body, as well as a nozzle with a nozzle hole through which the fuel gas flows out, and a diffuser which mixes the fuel gas supplied via the nozzle and the gas discharged from the fuel cell and returns it to the suction port. Furthermore, a needle-shaped component is received on one side of the body, which extends axially along the nozzle into a cavity provided therein. A first and a second diaphragm are arranged opposite one another.

[0004] US 2016 / 0 003 239 A1 discloses a valve unit for regulating the flow of working fluid between a working chamber of a fluid processing machine and both a first and a second working fluid line.

[0005] It has been found that, for example, metering valves used in fuel cell applications, especially for hydrogen, current metering valve designs only have a small mass flow spread. A larger mass flow spread, on the other hand, is advantageous for good adaptation of the metering valve to different operating conditions, especially when conflicting requirements exist for partial load operation of the metering valve and its full load operation. Description of the invention

[0006] According to the invention, a metering valve for a fuel cell arrangement is proposed, which has a split magnet armature. The magnet armature comprises a plunger armature that actuates a first seat of the metering valve, and furthermore a plate armature that actuates a second valve seat of the metering valve for a fuel cell arrangement proposed according to the invention. By designing the magnet armature as a magnet armature divided into the plunger armature and the plate armature, two seats of the metering valve can be actuated independently of one another, thereby achieving a greater mass flow spread of the fluid to be metered, in particular of gaseous hydrogen. The two seats provided in the metering valve proposed according to the invention are preferably switched independently of one another, with one seat opening first, since the magnet is supplied with two different currents.First, the seat closed by the plate armature opens, as the plate armature has greater dynamics due to its lower mass. The use of two sequentially opening seats allows for considerable design flexibility with regard to the mass flows that can be achieved with the metering valve proposed according to the invention.

[0007] In an advantageous embodiment of the metering valve proposed according to the invention, the plunger actuates a first seat located in the lower region of the metering valve. The first seat is either opened or closed by the plunger. The plate armature opens or closes the second seat, which is formed in the valve housing of the metering valve proposed according to the invention.

[0008] The metering valve proposed according to the invention has a working air gap between the plunger and a magnetic core that is larger than the initial air gap between the plate armature and an air gap disk. The plunger, which opens a seat, and the plate armature, which opens a seat, are designed differently with regard to their air gaps and open sequentially. The plate armature, which has a smaller air gap, is significantly more dynamic due to its reduced mass and requires less current to attract, i.e., to open the associated seat.

[0009] The metering valve proposed according to the invention comprises a valve housing having at least one elevation in the region of the second seat. A fluid channel opens into the at least one elevation formed on the second seat in the valve housing of the metering valve. The plate armature, through which the second seat of the metering valve proposed according to the invention is actuated, has at least one opening. The opening enables the plate armature to be guided independently of the plunger armature, such that the at least one opening formed in the plate armature is penetrated by a projection on the valve housing with a complementary geometry.

[0010] In a further embodiment of the metering valve proposed according to the invention, the plate armature is supported on a sleeve which, on the one hand, magnetically separates the magnetic core and the plunger armature and the plate armature from one another and, on the other hand, is accommodated in a stationary manner in the valve housing between a housing which encloses the magnetic coil and, on the other hand, is located above the valve housing on which the plate armature is guided.

[0011] An interior space on the metering valve, in which the solenoid coil is accommodated, is sealed against the fluid to be metered by a sealing element accommodated on the sleeve, in particular designed as an O-ring.

[0012] The invention further relates to a use of the metering valve in a fuel cell arrangement. Advantages of the invention

[0013] The inventively proposed design of a metering valve with a first seat and a second seat allows for a greater spread of the mass flow of the fluid to be metered, in this context, hydrogen gas. Due to the sequential opening of the two seats, which are opened by the plunger and the plate armature, a greater mass flow spread can be achieved in the metering valve proposed according to the invention. The larger mass flow spread allows for improved adaptation of the metering valve proposed according to the invention to different operating conditions, in particular to conflicting requirements of the metering valve under full load and idle, as well as under operating conditions corresponding to partial load.Different mass flows, which can furthermore be achieved by the metering valve proposed according to the invention, are determined on the one hand by a corresponding design of the flow cross sections with regard to the diameter of the bores, for example by the diameter of the fluid channel opening at the second seat, which runs through the valve housing of the metering valve proposed according to the invention.

[0014] The solenoid coil arranged in the housing of the metering valve proposed according to the invention allows the first seat to be opened by the plunger armature by energizing the solenoid coil with high currents and attracting the plunger armature through the magnetic core. Due to the smaller air gap between the plate armature and the air gap disc, the second seat, which is located in the valve housing of the metering valve, opens at lower currents.

[0015] By dividing the magnet armature into a plunger mounted on a bearing rod and a plate armature mounted in the valve housing, a sequential actuation option is created, i.e., the possibility of opening the first and second seats of the metering valve proposed according to the invention relative to one another. The plate armature is mounted on a sleeve arranged stationary in the metering valve proposed according to the invention and serving for magnetic separation, actuated by a return spring. Actuation occurs independently of the actuation of the plunger, upon flow through the solenoid coil surrounding the magnetic core.

[0016] A sealing element is located on the sleeve, which is fixedly mounted in the metering valve proposed by the invention. This sealing element is embedded in a circumferential groove in the sleeve and seals the chamber of the metering valve in which the solenoid coil is located. The sleeve also serves a further function as a magnetic separator between the magnetic core and the armature. Short description of the drawings

[0017] The invention is described in more detail below with reference to the drawing.

[0018] It shows: Fig. 1 a metering valve, in the lower area of ​​which there is a first seat and a second seat, which is designed in the metering valve proposed according to the invention, Fig. 2 a detailed view of the valve housing in the area of ​​the plate anchor, Fig. 3 a mass flow / time characteristic curve, Fig. 4 and Fig. 5 further characteristic curves. Embodiments of the invention

[0019] Fig. 1 shows a dosing valve according to the invention.

[0020] From the representation according to Fig. 1 shows a metering valve 1, on which a fluid inlet 2 and a fluid outlet 3 are provided in the lower area. In the case of the metering valve 1 according to Fig. 1 The fluid to be dosed is in particular a gaseous fluid, for example hydrogen. By means of a pressure regulator arranged in the lower area of ​​the dosing valve 1 according to Fig. 1, the fluid inlet 2 is separated from the fluid outlet 3. The opening and closing of the first seat 4 in the lower area of ​​the metering valve 1 occurs by energizing a solenoid 10, which is enclosed by an annular magnetic coil. The magnetic coil is energized via a connector plug; a sealing element 5 is located between the fluid inlet 2 and the fluid outlet 3. A solenoid 10 is received on a bearing rod 24 that can be moved in the vertical direction. Its end face, defining a working air gap 22, lies opposite a magnetic core 12, which in turn is open in a sleeve 16. The sleeve 16 serves as a magnetic separation between the solenoid 10 and a plate armature 14. The magnetic coil 42 is enclosed by a housing 26. The interior of the housing 26, in which the magnetic coil 42 is located, is sealed by a sealing element 18 that can be configured, for example, as an O-ring.The sealing element 18 is received in a U-shaped groove which is received in the sleeve 16. By means of the sealing element 18 received in this groove, which is preferably designed as an O-ring, the interior of the housing 26 of the metering valve is sealed as shown in . Fig. 1 sealed against the fluid to be dosed.

[0021] A penetration surface designated by reference numeral 20 is formed in the area of ​​a working air gap 22, which is formed by the beveled end faces of the magnetic core 12 and the plunger 10. A gap is formed between the circumference of the bearing rod 24 and the circumference of the magnetic core 12.

[0022] On the underside of the housing 26, in which the magnetic coil 42 is accommodated, there is an air gap disk 30. Between this and the upper end face of the plate armature 14, an initial air gap 28 is defined by the thickness of this air gap disk 30, which defines an initial air gap 28 and is smaller than the working air gap 22 between the magnetic core 12 and the plunger armature 10. As can be seen from the illustration according to Fig. 2, the plate armature 14 is acted upon by a return spring 32. The plate armature is supported on the sleeve 16 by the return spring 32. The plate armature 14 has a number of openings 36 on its plate-shaped surface, which extends horizontally and rotationally symmetrically around the bearing rod 24. Corresponding projections 44, which are formed on the valve housing 34, protrude through these openings 36 of the plate armature 14. The projections 44 on the valve housing 34 are also supported on the sleeve 16. Thus, the plate armature 14, which is not connected to the plunger armature 10 and not to the bearing rod 24, is movable relative to the plunger armature 10.

[0023] Through the plate anchor 14 as shown in Fig. 2, a second seat 40, which is located in the valve housing 34, is opened or closed. The second seat 40 is formed on the one hand by the lower end face of the plate armature 14 and on the other hand by at least one elevation 38 (compare illustration according to Fig. 3), which is formed in the valve housing 34. In the area of ​​the at least one elevation 38 in the valve housing 34, a corresponding fluid channel 46 opens. If the plate armature 14 - which is acted upon by the return spring 32 - is in the closed state, the fluid channel 46, which opens in the area of ​​the at least one elevation 38, is closed and no fluid can escape via the fluid channel 46. The degree of opening of the second seat 40 is determined by the housing of the initial air gap 28, the height of which is defined by the thickness of the air gap disc 30. As can be seen from the illustration according to Fig. 2, the working air gap 22 between the magnetic core 12 and the upper bevelled end face of the plunger 10 is larger than the initial air gap 28 above the second seat 40.

[0024] From the detailed representation according to Fig. 2 shows that the plate armature 14 comprises an opening 36, for example an arcuate opening. This opening 36, which is located in the plate-shaped region of the plate armature 14, is penetrated by a projection 44 formed in the valve housing 34. The plate armature 14 can comprise a number of arcuate openings 36, for example three openings 36 formed at an angle of 120° to one another or four openings 36 formed at an angle of 90° to one another in the surface of the plate armature 14. Since the plate armature 14 is only acted upon by the return spring 32, which in turn is supported on the stationary sleeve 16, an independent bearing of the plate armature 14 for actuating the second seat 40 results in relation to the plunger armature 10, which is received on the bearing rod 24.

[0025] The invention proposed based on the Fig. 1 and Fig. The metering valve 1 for hydrogen, described in more detail in Figure 2, is preferably used in a fuel cell arrangement. The metering valve 1 has the working air gap 22, which is located between the opposite end faces of the magnetic core 12 and the plunger 10. The resetting of the plunger 10 takes place via a Fig. 1 and Fig. 2, a low-force return spring (not shown) is used. In contrast, the plate armature 14 of the split magnet armature has a small initial air gap 28. This allows a high magnetic force to be generated with a relatively small drive current. The plate armature 14 is reset via the return spring 32, which generates a high sealing force at the second seat 40. Magnetic sticking is prevented by the air gap disc 30, which is arranged opposite the end face of the plate armature 14 on the underside of the housing 26, which accommodates the magnet coil 42. Furthermore, the air gap disc 30 prevents the plate armature 14 from magnetically sticking to the housing 26. Magnetic separation is achieved via the sleeve 16. The sleeve 16 also has the task of holding the valve housing 34. The plate armature 14 is provided with openings 36; furthermore, the valve housing 34 has elevations 38.The plunger 10 is connected to the bearing rod 24 and penetrates the magnetic core 12 in the area of ​​the penetration surface 20. The plug-side mounting of the plunger 10 is effected via a second one shown in the illustration according to . Fig. 2 and Fig. 3 Bearing not shown. The magnetic circuit is closed externally by the housing 26.

[0026] The second seat 40 allows for a further degree of freedom in the design of the mass flow of the fluid to be metered, in this case hydrogen. Depending on the design of the seating surfaces of the first seat 4 and the second seat 40, different valve characteristics can be achieved (see Fig. 3 to 5).

[0027] Fig. 3 shows a mass flow / time characteristic curve.

[0028] Fig. 3 shows a mass flow / time characteristic curve 50, in which the mass flow ṁ is plotted against the time axis 58. As soon as the second seat 40 is opened by the plate armature 14, a mass flow 52 is established. Depending on the dimensioning of the fluid channel 46, which is established through the valve housing 34 to the second seat 40, the mass flow 52 flows when it opens. With a higher current flow to the solenoid coil 42, in addition to the opened second seat 40, the first seat 4 opens because the solenoid plunger 10 is attracted. Depending on the design of the flow cross sections, a mass flow 54 is established in this case, corresponding to the mass flow that flows through the already open second seat 40. In addition, when the first seat 4 is opened, the mass flow is added by corresponding current flow to the solenoid 10, which flows in the direction of the fluid outlet 3 when the first seat 4 is open (cf. Fig. 1) flows. Depending on the flow geometry, a mass flow spread 56 results as a function of the geometric parameters. A mass flow spread 56 is also already given by the fact that, according to the energization of the magnetic coil 42, the mass flow 52 only flows when the second seat 40 is open and a further increase in the mass flow in the direction of the fluid outlet 3 can be brought about. In addition to the open second seat 40, i.e. when the plate armature 14 is attracted, provided that there is appropriate energization, the first seat 4 opens by appropriate energization of the plunger 10 and the mass flow 54 is established, which is significantly greater than the mass flow 52 that occurs when only the second seat 40 is open. From the mass flow / time characteristic curve 50 according to Fig. 3 shows that the second seat 40 opens first due to the greater dynamics of the plate armature 14 at a first current level, and upon a further increase in the current level, the first seat 4 opens sequentially with the second seat 40 already open. During the time period t1, the second seat 40 is open, while during t2, both seats 4, 40 are open.

[0029] Fig. 4 shows the resulting average mass flows 62, 64 in a mass flow / time characteristic curve 50, plotted over the time axis 58. The plotted mass flows 62 and 64 represent average mass flows. During t1, the second seat 40 is open, while during t2 both seats 4, 40 are open.

[0030] In another variant, which is Fig. 5 is shown schematically, a mass flow / time characteristic curve 50 can be set, in which, with appropriate current supply to the magnetic coil 42, the second seat 40 is opened only for short periods of time, so that according to the Fig. 5, individual quantity pulses 60 can be generated in the direction of the gaseous medium in the fluid outlet 3. In this case, the metering valve 1 proposed according to the invention is energized in such a way that the first seat 4 remains substantially closed and the quantity pulses 60 emitted sequentially in quick succession are generated exclusively by a corresponding energization duration.

[0031] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of expert practice.

Claims

[1] Metering valve (1) for a fuel cell arrangement, wherein the metering valve (1) comprises a magnetic armature (10, 14) which is accommodated in a valve housing (34) and is actuated via a magnetic coil (42), wherein the magnetic armature (10, 14) is divided into a plunger armature (10) and a plate armature (14), each of which opens or closes a seat (4, 40), characterized by in that the solenoid armature (10) opens or closes a first seat (4) and the plate armature (14) opens or closes a second seat (40) which is formed in the valve housing (34), wherein the plate armature (14) is supported on a sleeve (16) which magnetically separates the magnetic core (12) from the solenoid armature (10) and the plate armature (14), and wherein an interior space of a housing (26) receiving the magnetic coil (42) is sealed by a sealing element (18), in particular an O-ring, received on the sleeve (16). [2] Dosing valve (1) according to claim 1, characterized bythat a working air gap (22) between the plunger armature (10) and a magnetic core (12) is larger than an initial air gap (28) between the plate armature (14) and an air gap disc (30). [3] Dosing valve (1) according to claim 1, characterized by that the valve housing (34) has at least one elevation (38) in the region of the second seat (40) into which a fluid channel (46) opens. [4] Dosing valve (1) according to claim 1, characterized by that the plate anchor (14) has openings (36) in which it is guided on the valve housing (34). [5] Dosing valve (1) according to claim 1, characterized by that the plate anchor (14) is movable independently of the actuation of the plunger anchor (10). [6] Use of the metering valve (1) according to one of claims 1 to 5 in a fuel cell arrangement.

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