Valve tappet rod

Abstract

The present invention relates to a valve tappet rod (1, 1") for a valve (100, 100") of a metering system (200) for metering material. The valve tappet rod (1, 1") has an elongated, generally cylindrical body having a tappet tip (60) at a forward end (B), a tappet head (10) in an opposite head region (A), and therebetween, from the tappet head (10) to the tappet tip (60), at least a first guide sleeve portion (20), a narrow portion (30), a second guide sleeve portion (40), and a fluid portion (50). The outer diameter (30d, 30d") of the narrow portion (30) is reduced compared to the outer diameters (20d, 20d", 40d, 40d") of the guide sleeve portions (20, 40). The invention further relates to a valve (100, 100") having a valve tappet rod (1, 1") of this type, and to a metering system (200) having a valve (100, 100") of this type or a valve tappet rod (1, 1") of this type.

Description

[Technical Field]

[0001] The present invention relates to a valve tappet rod for a valve of a metering system, to a valve having such a valve tappet rod, and to a metering system having such a valve or such a valve tappet rod. [Background technology]

[0002] A (micro)metering system for precisely metered delivery of liquid or viscous metering material, having an actuator unit for driving the valve tappet rod of a valve of the type mentioned at the outset, is known, for example, from DE 10 2017 122 034 A1. Furthermore, very small amounts of metered material can thereby be precisely delivered to the target surface of a workpiece without the metering system itself coming into contact with said target surface. The valve tappet rod here is an elongated body that is very thin in relation to its length and is guided longitudinally movably in a suitable counterpiece of the valve (here, for example, a sleeve or guide sleeve). By means of the valve tappet rod, the desired, precisely metered amount of metering medium or material can be extruded or dispensed in a controlled manner from the nozzle chamber or valve chamber, i.e., from a reservoir, through an opening in the nozzle chamber.

[0003] The valve tappet rod is now guided over a very large distance in the valve sleeve, which causes friction and wear. To ensure the longest possible durability of the part, it is lubricated with specific oils or greases, as is common for such bearings or guides. This actually has a positive effect on the wear of the valve tappet rod and guide sleeve. However, the use of specific lubricants also increases the damping of the system and therefore affects the force and speed at which the valve tappet rod can be moved in the guide sleeve. Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to provide an improved valve tappet rod and corresponding valve or metering system that is more resistant to wear and exhibits less damping during movement. [Means for solving the problem]

[0005] This problem is solved by a valve tappet rod according to claim 1, a valve according to claim 9 and a metering system according to claim 12.

[0006] A valve tappet rod according to the invention for a valve of a metering system for metering material conventionally comprises an elongated, approximately cylindrical body, which is to be understood as a rod-like object, preferably rotationally symmetrical in the longitudinal direction, which, on the one hand, is longer than it is wide (thickness), and, on the other hand, is preferably made of solid material (i.e., not hollow inside).

[0007] Alternatively, however, it is also conceivable to configure the body of the valve tappet rod so that it is hollow inside in order to save weight, for example by manufacturing it in two parts from an elongated sleeve with a welded, worn tappet tip, or from at least two materials joined by a suitable method.

[0008] In the following, the valve tappet rod will, for the sake of brevity, also be abbreviated synonymously by "tappet".

[0009] At the front longitudinal end of the body, the tappet is configured with a tappet tip. Contrary to what may be implied by the chosen term, however, this term does not necessarily refer to the pointed character of such a tappet tip, but rather simply defines only the frontmost (i.e., discharge-side) part of the tappet's body. The tappet tip thus represents the front face or shape of the body, which may, for example, be slightly rounded, spherical, flattened, or provided with a spherical or parabolic depression. It generally (as in conventional spice grinders) serves to displace, i.e., for example, push aside, a material, such as a metered material, as will be made clearer further below. This means that the tappet tip comes into contact with the metered material and is responsible for its actual supply or discharge.

[0010] At the head region opposite the body and spaced longitudinally therefrom, the tappet forms a tappet head. The head region is not necessarily to be understood as the actual end of the body. It can also refer to a kind of "flange" in the end region of the body if the end region does not directly define the end. The tappet head additionally serves as the effective region of an actuating element, for example an actuator unit, as will be explained further below.

[0011] The function and role of the tappet tip and of the tappet head of the tappet will become clearer and more clearly apparent below with respect to the valve according to the invention and to the metering system in which the valve tappet rod is formed as a component or replacement part.

[0012] As just mentioned, the tappet head is spaced apart from the tappet tip of the tappet. To this end, according to the invention, the following parts adjoin each other along the body (from the tappet head to the tappet tip):

[0013] First, the first guide sleeve part preferably abuts the tappet head side by side. This guide sleeve part is formed with an outer diameter that allows it to be accurately introduced into the associated tappet centering screw or guide sleeve during valve assembly. Such guide sleeves used in valves for straight and centered guidance of the valve tappet rod have, for example, at least one continuous bore with a preferably uniform inner diameter of the tappet. To prevent the tappet from sliding completely through the guide sleeve, at least the outer diameter of the tappet head is larger than the inner diameter of the guide sleeve. Therefore, when the tappet is introduced into the guide sleeve, it abuts on the guide sleeve at the latest against the tappet head, but in particular already indirectly against a restoring element attached between the tappet head and the guide sleeve.

[0014] Adjacent to the first guide sleeve portion is a narrow portion, which in turn is adjacent to the second guide sleeve portion, so that the narrow portion is surrounded by two guide sleeve portions.

[0015] As the name already suggests, the cross section of the narrowed portion is reduced (or narrowed) with respect to the adjacent portions. The narrowed portion here has a smaller or reduced outer diameter compared to the outer diameters of the first and second guide sleeve portions. That is, the cross section or cross-sectional area through the body of the tappet is smaller in the region of the narrowed portion than in the adjacent regions of the guide sleeve portions.

[0016] Further towards the tappet tip, the fluid section adjoins the second guide sleeve section (at the opposite end of the narrow section). The fluid section itself in turn also adjoins the tappet tip. In a preferred variant of the tappet, the tappet tip may here additionally be integrated therebetween (i.e. between the tappet tip and the fluid section), as will be further explained below. The fluid section refers to the part along the body of the tappet that is in contact with the metered material to be metered or dispensed during operation of the tappet in a valve of the metering system. The structure of the valve and of the metering system will likewise be explained in more detail below.

[0017] A valve according to the invention for a metering system comprises a valve tappet rod according to the invention.

[0018] As is typical for valves, it here also preferably comprises at least one generally sleeve-shaped or hollow-cylindrical valve body, preferably tapered overall conically towards the front, which valve body surrounds or borders the guide sleeve, preferably along its outer surface all around.

[0019] The valve tappet rod is movably guided in this guide sleeve in the valve body, i.e. the guide sleeve forms a bearing for the valve tappet rod in the valve body, in which, according to the invention, at least the guide sleeve portion of the valve tappet rod resides partially and the narrowed portion entirely during intended operation.

[0020] To allow the guide sleeve to be introduced into the valve body during installation, at least one cover surface of the valve body preferably has a corresponding opening. After introduction, the guide sleeve (with the introduced valve tappet rod, pressed restoring element, and pressed sealing element) can be screwed into the valve body from above, clamped, clicked, and / or engaged so that the valve body is closed upward. On the base surface located opposite the cover surface, there is a further opening in the valve body, to which, as mentioned, the valve body as a whole tapers slightly conically. This opening is the metering or nozzle opening of the valve, or here, this opening is fitted with a nozzle having a nozzle opening through which the metered material is dispensed during intended operation. Simply put, the nozzle opening can be opened or closed here by the tappet. This means that the tappet here serves as a closing element of the valve (or of the valve's nozzle). More precisely, the nozzle opening may be opened or closed by a tappet (in particular by the tappet tip or a tappet tip adjacent to it), which is pressed into a valve seat or sealing seat of the valve (or of the nozzle) and is movably mounted relative to this nozzle opening. The valve body thus forms both a kind of "fitting" for the guide sleeve and, furthermore, a closable internal space into which the metered material can be introduced for metering.

[0021] In order for the tappet to return to its starting state (or to its starting position again after the discharge movement), the valve may optionally further comprise a restoring element, for example a spring element or the like, which, in the assembled state of the valve, is attached between said tappet head of the valve tappet and the stop of the guide sleeve.

[0022] The valve further comprises a nozzle chamber (or valve chamber) corresponding to the interior already described above. The valve chamber defines a lower region on the side of the valve body facing away from any restoring element. Preferably, a supply channel (or supply opening) may be formed in the wall of the valve chamber, so that metered material can be introduced into the valve chamber. The valve chamber then contains metered material for the metering system during operation, which is supplied into the valve chamber via the supply channel of the valve and the supply line of the metering system, so that the metered material can be dispensed by the tappet from the valve chamber or nozzle chamber in a precisely metered manner.

[0023] According to the invention, the valve further comprises a sealing element for sealing between the guide sleeve (in particular the hollow cylindrical region of the guide sleeve) and the valve chamber of the valve body, in which the metering material is located at least for operation, which means that the (fluid) region in contact with the metering material, as intended, is sealed from the rest of the valve.

[0024] Such a generally annular sealing element preferably has a central tappet opening with an inner diameter that provides a tight seal against the tappet. In the intended assembled state of the valve, in the metering system, the sealing element is preferably positioned relative to the guide sleeve so that it is located in front of the guide sleeve within the valve body, where it is pressed in a sealing manner between the edge of the hollow cylindrical valve chamber of the valve body and the edge of the guide sleeve. It thus also seals radially outward. This prevents metering material from reaching the hollow cylindrical region of the guide sleeve (described further below) and, potentially, between the tappet and the guide sleeve, unless the sealing element is damaged. Further preferred solutions for preventing this problem are described further below.

[0025] The metering system according to the invention comprises a valve according to the invention having a valve tappet rod according to the invention. Furthermore, the metering system may comprise a supply line to the supply channel of the valve for supplying metered material into the valve chamber or nozzle chamber and, optionally, a metered material storage holder (e.g. for a metered material container such as a cartridge, bottle, etc.). The supply line here connects the metered material container (preferably inserted into the metered material storage holder) with the supply channel opening through the wall of the valve in the valve chamber.

[0026] Instead of the metered material storage holder, the metering system can also be connected to a tank or container from which the metered material is continuously fed or guided into the valve chamber via a supply channel. For this purpose, the container can be connected to the supply channel or fluid channel of the valve via a supply line. The metered material in the metered material container, preferably held by the metered material storage holder, can be acted upon by pressure so that the metered material reaches, inter alia, the valve chamber via the supply channel. Preferably, the metered material container can also be acted upon by pressure for operation, for example by a pump (or similar) of the metered material storage holder. It is also conceivable that the metered material flows into the valve chamber by itself (or by gravity), especially if it is very liquid.

[0027] As is usual, the metering system further comprises an actuator unit for actuating or accelerating the valve tappet rod, which actuator unit applies or generates a stroke directly or indirectly to the tappet head. The actuator unit can transmit or apply a desired time-limited impact to the tappet head of the tappet, for example by means of a lever, actuator, etc. Similarly, but with a corresponding configuration or embodiment, the actuator unit can also apply an impact or traction force to the tappet, which in turn returns the tappet.

[0028] Due to the reduced diameter according to the present invention in the narrow section between the two guide sleeve sections, it can be achieved that the damping between the valve tappet rod and the associated surrounding guide sleeve is reduced (or decreased) during relative movement of the valve tappet rod with respect to the guide sleeve.

[0029] Furthermore, the narrowed portion of the valve tappet rod can advantageously be used to form a lubricant reservoir that permanently lubricates the valve tappet rod or tappet sufficiently in operation with the intended discharge and retraction movements, so that material friction and wear are kept as low as possible. For this purpose, a thin film of lubricant can be applied to the narrowed portion before installation.

[0030] Additionally or alternatively, the narrowed portion may be used to take the wear or material abrasion from the movement of the tappet so that the tappet or valve or metering system remains in a functioning state for a longer period of time.

[0031] Due to the narrowed portion being formed on the tappet, the guide sleeve itself may advantageously be generally smooth (or simple), i.e., without grooves introduced into the bore, recesses, etc. This considerably facilitates that the guide sleeve can preferably be at least partially formed of a hard material, such as, for example, a metal matrix composite material (e.g., a hard metal), preferably having hard material particles. Further hard materials are listed in addition below. In practice, it has proven to be extremely laborious and expensive to configure an inner bore with a hard material guide sleeve (especially a hard metal guide sleeve) to be larger in the middle than in the start and end regions of the inner bore.

[0032] Furthermore, particularly advantageous configurations and further developments of the invention will become apparent from the dependent claims and from the following description, whereby independent claims of one claim category may be further developed in the same way as dependent claims of another claim category, and in particular, further individual features of different exemplary embodiments may be combined into new exemplary embodiments.

[0033] During installation of the valve for its intended operation, the valve tappet rod is installed in a valve body having a valve chamber with two openings. Here, it extends into the valve chamber through the opening on the tappet head side and projects (over a distance of a defined stroke length) to the nozzle opening on the opposite side of the valve chamber, so that it closes at the full deflection (i.e., maximum stroke length) of the tappet in the tappet-disengaged closed position. In the opening of the valve chamber on the tappet head side, the fluid part of the tappet is positioned in a state where the annular sealing element is pressed (or overlapped) and thus permanently and tightly closed. At the same time, the tappet, or at least the tappet tip, is located at the opposite end of this starting position, over the distance of the maximum stroke length, in the valve seat or sealing seat of the nozzle (or the outlet opening of the nozzle insert for the nozzle) to close the nozzle opening in the tappet's disengaged closed position and thus limit the metering amount.

[0034] Depending on the application, the valve chamber is filled (via a supply channel in the valve chamber) with a corresponding (suitable) metering material which may be introduced into the valve chamber of the metering system for this purpose from a metering material container and acted upon by pressure, or which may already be present in the metering material container in a state in which it can be acted upon by pressure. Possible metering materials to be used are, for example, adhesives, solder paste or soldering paste, water, oil, paint, lacquer, etc.

[0035] The metered material can then be extruded or dispensed from the valve chamber onto the workpiece in a desired, precisely metered amount by a tappet in combination with a suitable nozzle (or by a nozzle insert for the nozzle). For metered dispensing of the metered material, for example, the actuator unit of the metering system generates a desired stroke or impulse (during the movement of the fluid part, the tappet tip, and the surrounding tappet tip) that is rigidly transmitted as a dispensing movement by the tappet head directly into the tappet tip of the tappet, in order to bring or dispense the metered material there. Depending on the desired dispensing of the metered material, the valve tappet rod is then reciprocated from the starting position at the desired frequency and for the desired duration during each stroke, i.e., moved at least partially into or out of the nozzle or sealing seat. For example, the tappet may dispense only half of its maximum stroke length in order to only reduce the metered amount between two strokes and not completely stop it.

[0036] Depending on the viscosity of the metered material, the valve can be operated in a so-called opening operation, in which the tappet tip is not moved into the valve seat between two strokes (and therefore the valve is not closed). This is conceivable in the case of viscous materials. The discharge of the metered material then occurs only by the forward movement of the valve tappet rod, which is moved towards the valve seat (so-called "jetting"), and not by the pressure of the metered material in the valve chamber. In the case of more easily flowing media, it is also naturally conceivable to operate the valve in such a way that it is always closed between two metering steps, for example by the above-mentioned restoring element. Furthermore, in the case of the opening operation, which is otherwise preferred here, the valve can, however, be closed, for example, if metering is not to be carried out for a longer period of time.

[0037] There are various possibilities for the configuration of the individual parts of the valve tappet rod:

[0038] The outer diameters of the respective guide sleeve portions of the tappets can be selected at most to be larger than they would be able to occlude their associated inner diameters of the guide sleeve with an exact fit, without excess play. The guide sleeve can therefore have a borehole inner diameter that is minimally larger than the outer diameter of the tappet in the guide sleeve portion. An example of such a fit can be, for example, approximately H7 / f7 or H7 / g6 (according to DIN 7157). The tappets can thus be guided in an exactly centered manner within the openings of the guide sleeve.

[0039] Preferably, the length and position of the narrowed portion along the tappet may be selected such that the narrowed portion moves only within the associated guide sleeve during intended delivery and retraction movements with a defined stroke, which may depend on the deflection or operation of the actuator unit, in operation of the tappet, i.e. the tappet may be formed such that the guide sleeve portion always remains at least partially within the guide sleeve during intended delivery and retraction movements of the tappet relative to the operating guide sleeve.

[0040] This ensures that the front opening of the guide sleeve is always closed and that no metering material can get in in this area (for example, if the sealing element were to be defective), i.e. access to the narrow part of the tappet is therefore permanently blocked at least partially over its longitudinal extent by the second guide sleeve part arranged therein.

[0041] In principle, the guide sleeve portions of the valve tappet may be configured with different outer diameters. Preferably, the outer diameters of the guide sleeve portions of the valve tappet rod may be of equal size, especially when the borehole inner diameters of the guide sleeves are of successively equal size.

[0042] The outer diameter of the narrowed portion may preferably be the same as the outer diameter of the fluid portion.

[0043] Preferably, the length of each guide sleeve portion of the tappet can be at least the maximum vibration amplitude (or maximum stroke) of the tappet, i.e. the given stroke length of maximum delivery or maximum rebound (i.e. the intended maximum target stroke length during intended operation), i.e. if each guide sleeve portion corresponds in length to at least the stroke length, a part of each guide sleeve portion always remains within the associated guide sleeve during such movement, so that no metered material can reach into the guide sleeve.

[0044] Alternatively, or in addition, the narrow portion of the tappet may be shorter than the overall length of the associated guide sleeve by at least two such maximum stroke lengths, whereby a similar objective may be achieved if the narrow portion is located intermediate the guide sleeve portions.

[0045] Preferably, the maximum target stroke length of the actuator unit stroke may be at least 0.25 mm, particularly preferably 0.5 mm, and most particularly preferably 1 mm.

[0046] If the actuator unit acts in only one direction and thus, for example, impacts the tappet head, a restoring element, as already mentioned, can optionally be inserted between the tappet head and the guide sleeve to return the valve tappet rod to its starting state after the discharge movement due to the stroke of the actuator unit. A particularly recommended restoring element for this purpose is a torsion coil spring, such as a helical coil spring. This consists, for example, of a helically wound wire and is characterized by being available in any desired variant and usually being particularly economical. Due to its helical or approximately hollow cylindrical shape, it can be at least partially pressed against the valve tappet rod by a corresponding selection of the inner diameter.

[0047] To ensure that the coil spring can only be pressed against the valve tappet rod (starting from the tappet tip) up to the tappet head, the tappet head can preferably be configured as follows: For example, it can have an actuating flange for an actuator unit of the metering system, e.g., as a stop and / or guide for the coil spring due to the elasticity (preferably a spring-loaded bearing) of the valve tappet rod relative to the associated guide sleeve. Such an actuating flange is to be understood as a flange or protrusion, or else an end piece or end tappet plate, formed so that the actuator unit can act on it, as appropriate, by a lever or actuator suitable for this, and thus generate the stroke already mentioned above in order to move the valve tappet rod as intended. Preferably, an actuator unit can be used for this, as disclosed in DE 2017122034 A1.

[0048] For the centered guidance of the coil spring, the tappet head preferably has, in addition to the actuation flange, a guide ledge, which can be arranged, for example, between the actuation flange and the first guide sleeve part. The guide ledge here can be configured flange-like, but it can also be realized simply as a kind of "step" or ledge.

[0049] This "step" (or ledge) may be abrupt or perpendicular to the actuation flange or to the first guide sleeve portion.

[0050] Preferably, the transition from the guide ledge to the adjacent portion may be fillet-like, i.e., the respective outer diameter continues via a short fillet, expanding or reducing the radius to a larger or smaller outer diameter in an "arc" manner. In this way, the transition is produced in a cutting process, as a lathe or milling machine can operate more quickly in succession without interruption between two different radii, and thus, for example, milling, turning, or grinding can be performed.

[0051] Particularly preferably, here the outer diameter of the guide ledge may be larger than the outer diameter of the first guide sleeve part. This is particularly advantageous if, for example, a coil spring is selected which has an inner diameter that is clearly larger than the outer diameter of the guide sleeve part, so that the coil spring is then mounted with a relatively large amount of play (i.e. loosely and as frictionlessly as possible) to the guide sleeve part.

[0052] Most particularly preferably, the outer diameter of the actuation flange may be greater than the outer diameter of the adjacent guide ledge.

[0053] Thus, as already mentioned above, it is thus achieved that, provided that an appropriately selected coil spring is used (which can be pressed against the guide ledge from the direction of the tappet tip and abuts against the actuating flange), the coil spring is guided in a centered manner on the guide ledge, and furthermore, the coil spring is held at its end towards the head area on the tappet by the actuating flange for the actuator unit, thus achieving the desired return or retraction movement of the valve tappet rod against the spring force of the coil spring.

[0054] There are also different possibilities for other transitions between further portions.

[0055] Preferably, the ledge can be configured steeper between the first guide sleeve portion and the narrow portion than at the transition between the narrow portion and the second guide sleeve portion. This offers advantages in terms of manufacturing techniques, since milling, turning, and / or grinding can be performed on the valve tappet rod being manufactured (e.g., in the direction from the tappet tip to the tappet head) in a continuous manufacturing process, without the need for corresponding reverse release and clamping or re-clamping. This also allows material wear of the tappet and the associated guide sleeve during operation to accumulate in this section without reducing the quality of the metering results of the metering system over a longer period of time. Furthermore, the narrow portion can be used as a lubricant reservoir, from which lubricant flows more easily in the direction of the second guide sleeve portion than in the direction of the first guide sleeve portion due to the steeper ledge there.

[0056] Tests have shown that components of the metering system thus need to be removed for cleaning purposes more rarely than in the absence of the narrow sections described above, which preferably have such transitions to adjacent sections, which in turn also brings technical, production and economic advantages.

[0057] As in a particularly preferred variant, the two guide sleeve portions may have the same outer diameter, and therefore the steeper ledge between the first guide sleeve portion and the narrow portion may at the same time be shorter than the transition between the narrow portion and the second guide sleeve portion.

[0058] Particularly preferably, the fluid portion has an outer diameter that is smaller than the outer diameter of the second guide sleeve portion. For example, the passage between these two portions may be continuous, stepped or abruptly reduced.

[0059] Preferably, the ledge can be formed "shoulder-like" between the second guide sleeve part and the fluid part. This shoulder then serves to position the sealing element already mentioned above on the shoulder on the tappet and can be held in this position along the tappet during the intended discharge or recovery movement of the tappet during operation. During assembly of the sealing element on the tappet, this shoulder therefore serves as a kind of "stop" or "positioning aid" when the sealing element is positioned on the tappet from the tappet tip.

[0060] Particularly preferably, the ledge may be configured with a fillet having a fillet radius of at least 0.01 mm, particularly preferably at least 0.1 mm, most particularly preferably at least 0.25 mm, and / or preferably a fillet radius of at most 2 mm, particularly preferably at most 1 mm, and most particularly preferably at most 0.5 mm.

[0061] To further secure the sealing element against displacement along the tappet, the fixed annular inner sleeve may be further integrated into the sealing element, the inner sleeve having an annular groove or tongue that may engage with a corresponding tongue or groove of the sealing element so that the inner sleeve is firmly secured within the sealing element. In this case, in the fully installed state, the inner sleeve may be positioned inside the sealing element over the sealing point of the sealing element on the tappet, for example, with a serpentine membrane seal as described further below, so that the shoulder-like ledge mentioned above may strike thereon. This may reinforce the membrane seal as a whole, which in turn may hold the membrane seal more stably and securely in the desired position on the tappet.

[0062] Preferably, the opening or bore of the sealing element (through which the tappet passes in the installed state) can be made smaller in size relative to the associated outer diameter of the tappet, i.e., it can thus be positioned particularly tightly relative to the radially inner annular first sealing point on the tappet and can thus also remain in the desired position during movement of the tappet. Overall, this allows for the tappet and the membrane seal not only to be fixed against sliding relative to one another in the intended placed or pressed state, but also to be connected to one another in a force-fit manner, i.e., therefore particularly tightly.

[0063] In the simplest case, the sealing element can be a conventional O-seal-like ring seal.

[0064] As already mentioned, the sealing element may preferably be a membrane seal, which, as a different type of ring seal, comprises a central opening through which the tappet extends during operation, and which opening may then be manufactured with a smaller size relative to the associated outer diameter so that it is particularly tight against the tappet and remains in the desired position during the movement of the tappet.

[0065] The membrane seal here may have an elastic transition area (or elastic flexible membrane) between a first sealing point around the tappet and a radially outer annular second sealing point between the guide sleeve and the valve chamber. The first sealing point here defines the circular inner edge of an opening in the center of the membrane seal, which in operation is located directly against the valve tappet rod or indirectly via a corresponding inner sleeve in the fillet. The second sealing point here means the radially outer annular sealing point, and therefore the annular contact surface between the guide sleeve and the valve chamber of the valve, where the membrane seal seals around the inlet opening of the valve tappet rod into the valve chamber.

[0066] In a particularly preferred variant, the membrane seal can be configured in a serpentine manner, i.e., by a serpentine membrane whose cross section extends from the central opening toward the outer edge in an undulating or serpentine manner. During the intended discharge or retraction of the tappet, in which the first radially inner sealing point moves fixedly with the tappet relative to the second (positionally fixed) radially outer sealing point between the guide sleeve and the valve chamber, the serpentine membrane can be easily deployed without the material itself being stretched or stressed. This membrane seal thus remains tight against the sealing points, particularly since neither the first nor the second sealing point is moved or stressed during movement. The serpentine configuration of the membrane seal has the advantage that a larger stroke length can therefore be realized.

[0067] In an alternative preferred variant, the membrane seal may rather be configured to be flat, i.e. to extend in a substantially straight line in cross section from the radially inner opening to the radially outer edge, The advantage of this embodiment is that it is clearly simpler to manufacture, saves more in terms of material and is therefore also more economical.

[0068] Particularly preferably, however, the sealing element can also be embodied as a sliding seal. Here, in the initial state, the seal can also be, for example, substantially flat. Furthermore, it can likewise be formed with a central opening or bore that is sized smaller relative to the valve tappet rod, through which the valve tappet rod is guided. The radially outer sealing point of the sliding seal can here remain positionally fixed. In contrast, the radially inner sealing point of the sliding seal on the central bore, which is made smaller, can slide along the valve tappet rod as it moves and seal there due to the tight fit with its smaller size.

[0069] Thus, optionally, the sliding seal may further comprise a spring element which increases the prestressing force with which the sealing element is pressed against the valve tappet rod, so that the sealing capacity is further improved. The sliding seal may here be arranged on the valve tappet rod, and the corresponding fillet may be configured in a direction towards the tappet head such that, upon movement of the valve tappet rod, no contact is made between the fillet and the seal, which slides as it is rigid.

[0070] The guide sleeve preferably extends beyond the threaded region of the guide sleeve on the tappet tip side and may thus surround the hollow cylindrical region already mentioned above, which forms a kind of "pre-chamber" around the opening of the bore of the guide sleeve on the tappet tip side. Centrally within this hollow cylindrical region, during operation, the tappet moves back and forth at the first sealing point radially inside the sealing element. Here, even during the intended discharge or retraction movement of the tappet, part of the second guide sleeve part (at least partially in the disengaged state of the valve tappet rod) and / or part of the fluid part of the tappet always remains within the threaded region of the guide sleeve.

[0071] In the event of a failure or leak of the sealing element, the hollow cylindrical region of the guide sleeve or the pre-chamber may preferably be formed with at least one drainage bore in its outer surface, so that metered material flowing out of the valve chamber, possibly through the seal into the pre-chamber, can be directed away via the drainage bore before being pushed or forced into the intermediate space between the tappet and the guide sleeve due to pressure from the drooping metered material (in the case of a fully filled pre-chamber). Thus, the pre-chamber cannot be filled in the event of a seal leak. Rather, the metered material can preferably flow or leak out of the drainage bore into a collection area specially designed for this purpose, such as a collection area in the valve body. This can inform the user of the metering system that the sealing element is damaged and should be replaced (e.g., by the formation of an open viewing window, if applicable, with an unobstructed view into the collection area in the wall of the valve body, at the height of the hollow cylindrical region of the guide sleeve in the region of the drainage bore). If necessary, for example, a camera or optical sensor or the like can also be used for this in a manner that supports the user. The drainage bore can thus serve as an indication to the user to quickly (as quickly as possible) reveal any sealing defects without damage to the workpiece and be able to remedy it in a material- and cost-saving manner.

[0072] In conventional metering systems, this possibility generally does not exist. The sensors or measuring devices installed in this respect are expensive and prone to errors. Therefore, even if it should be possible to measure the seal leakage in any way to determine, if applicable, when the sealing element is damaged and must be replaced, it is thus more complicated and more costly.

[0073] The drainage bore is preferably positioned so as to technically notify the user that a sealing leak is present (eg it can be directly observed or seen from the outside).

[0074] In known metering systems, a seal leak generally only becomes apparent when the metered material has already flowed out of the metering system and dripped or flowed onto the workpiece. To prevent this problem from occurring in the first place, or even prevent it from happening, the seal is therefore preventatively replaced or replaced with a new one after a specified number of use cycles. However, the seal is therefore not worn out until it actually fails, and this method is neither economical nor sustainable.

[0075] Regarding the dimensions of the individual parts in the longitudinal direction of the tappet and also in its transverse direction, there are also different possibilities, which are further described below.

[0076] In a preferred variant, the tappet may have a tappet tip between the tappet tip and the fluid part, as already mentioned above. Such a tappet tip is understood to mean a section along the tappet that has an increasing or decreasing outer diameter (depending on the point of view) from its start point to its end point. That is, the tappet tip may therefore adjoin the tappet tip at one end and the fluid part at the other end. Here, the outer diameter of the tappet tip may taper conically from the outer diameter of the fluid part to the outer diameter (or twice the radius) of the tappet tip. That is, the outer diameter of the tappet tip may decrease conically towards the tappet tip.

[0077] During operation in the assembled state of the valve, the tappet is positioned within the valve so that its entire fluid section is located within the valve chamber. At the upper end of the fluid section, a membrane seal is positioned on a shoulder against the second guide sleeve section so that the valve chamber is sealed upward. Adjacent to the fluid section at its lower end are the tappet tip and the tappet tip, which, in a disengaged or biased closed position (in which the restoring element is maximally compressed or alternatively separated), are positioned within the sealing or valve seat of the nozzle or nozzle insert that can be used as a nozzle. In the starting position, the tappet tip is spaced from the valve seat by the stroke length and can then be discharged to the closed position as appropriate during the stroke. Preferably, the tappet tip and the conical tappet tip are adapted in shape or external shape and size to precisely fit the conically tapering internal shape of the associated nozzle or nozzle insert that can be inserted for the nozzle, to provide a tight seal in the closed position.

[0078] Preferably, the length of the tappet tip for the associated nozzle or for the nozzle insert as a nozzle of the valve can vary depending on the radius of the tappet tip, which in turn can also depend on the desired application and metering material.

[0079] Alternatively, or in addition, the length of the tappet tip for the associated nozzle may preferably be at least 0.5 mm, particularly preferably at least 2.5 mm, and most particularly preferably at least 5 mm.

[0080] Alternatively, or in addition, the length of the tappet tip for the associated nozzle may preferably, but not necessarily, amount to a maximum of 5 mm, particularly preferably a maximum of 7.5 mm, most particularly preferably 10 mm.

[0081] The invention will now be explained in more detail once again using exemplary embodiments and with reference to the accompanying drawings, in which like components are provided with like reference numerals in the various figures and in which the figures are generally not drawn to scale. [Brief explanation of the drawings]

[0082] [Figure 1] 1 shows a perspective view in three-quarter section of a first variant of a first exemplary embodiment of a valve tappet rod according to the invention, in a first exemplary embodiment of a valve according to the invention, with a serpentine membrane seal, in a partially shown metering system; [Figure 2] 3A is a perspective view in three-quarter section of a second variant of the first exemplary embodiment of a valve tappet rod according to the present invention in an exemplary embodiment of a valve according to the present invention according to FIG. 1 with a flat membrane seal; FIG. [Figure 3] 2 is a three-quarter cross-sectional perspective view of a second exemplary embodiment of a valve tappet rod according to the present invention, in a second exemplary embodiment of a valve according to the present invention, of a partially shown metering system having a serpentine membrane seal as in FIG. [Figure 4] 2 is an exploded view of a first exemplary embodiment of the valve tappet rod according to the present invention of FIG. 1; FIG. [Figure 5] 4 is an exploded view of a third exemplary embodiment of the valve tappet rod according to the present invention of FIG. 3; FIG. [Figure 6] 2 is a rough schematic cross-sectional view of the structure of the metering system of FIG. 1 with a sliding seal; DETAILED DESCRIPTION OF THE INVENTION

[0083] 1-3, similar parts of several exemplary embodiments of a metering system 200 according to the present invention will be described, firstly with a valve 100, 100″ according to the present invention, in which only a portion of the metering system 200 is shown, with the remaining components of the metering system 200 omitted at the expense of an enlarged view of the valve 100, 100″.

[0084] FIG. 6 shows an overall view in this regard in which the entire structure of a metering system as known from DE 10 2017 122 034 A1 is shown, by way of example, broadly and diagrammatically in slightly modified form in partial cross section. In doing so, in particular here, the sealing element 150 is a sliding seal that is arranged around the tappet 1, 1″ and slides therewith on the radially inner sealing point when the tappet 1, 1″ moves. In order to clarify the interaction of the components essential to the invention here, only the parts of the valve 100, 100″ and the actuator unit 220 of the metering system 200 that are necessary for operation are shown diagrammatically in cross section. The actuator unit 220 is therefore only shown broadly and diagrammatically, and details of the valve 200, 100″ are not shown in the overview due to the minimized representation. This applies in particular to details of the valve tappet rod 1, 1″, such as its different parts 20, 30, 40, 50, 55, etc., which will be described in more detail below. Furthermore, the valve 100, 100″ shown in FIG. 6 is only representative of all valves 100, 100″ according to the invention, as shown in more detail, for example in one of the FIGS. 1 to 3.

[0085] In contrast, Fig. 1 shows a particularly preferred variant of the exemplary embodiment of the metering system 200 with a serpentine membrane seal 150m as sealing element 150 in the valve 100. In Fig. 2 a further preferred variant of the exemplary embodiment of the metering system 200 with a flat membrane seal 150f in the valve 100 is shown. With the exception of the membrane seals 150f, 150m and the correspondingly adapted dimensions 30l, 40l of the narrow part 30 and the second guide sleeve part 40 of the valve tappet rod 1, all components are identical here. Fig. 3 shows an exemplary embodiment of the metering system 200 according to the invention for a second exemplary embodiment of the valve 100" according to the invention.

[0086] In the valve 100 shown in FIG. 1, a first variant of the first exemplary embodiment of a valve tappet rod 1 according to the invention is arranged as shown in FIG. 4. FIG. 2 shows a second variant of the first exemplary embodiment of a valve tappet rod 1 according to the invention in such a valve 100. This variant has a shortened narrow section 30 and therefore a lengthened second guide sleeve section 40, so that the tappet 1 has a somewhat higher braking friction compared to the first variant (but still clearly lower overall compared to without the narrow section 30). In FIG. 3, a third exemplary embodiment of a valve tappet rod 1" according to the invention is arranged in the valve 100", which can be seen in isolation in FIG. 5.

[0087] As can be seen in Figures 1 to 3 and 6, the main components of these metering systems 200 include, in addition to the valves 100, 100", a hydraulic unit 211 (partially shown here in Figure 6, which is formed in accordance with the basic principle and by bayonet coupling to the actuator unit according to DE 102017122034 A1, simultaneously with the already known bayonet hydraulic part 211), and a valve support 212 which surrounds the valves 100, 100" (in the region of the valve chambers 104, 104" of the valve bodies 101, 101" of the valves 100, 100") and serves to connect the valves 100, 100" with a supply line for the metered material from a metered material container (not shown). The supply line in the connected state is now adjacent to the supply channel 180 in the valve 100, 100" (more precisely, the supply channel 180 into the valve chamber 104, 104 passing through the walls 104w, 104w" of the valve chamber 104, 104" of the valve 100, 100").

[0088] The metering system 200 as already described above and to be seen in FIG. 6 further comprises an actuator unit 220 for actuating the valve tappet rod 1, 1″ (further details about the actuator unit 220 will be explained in more detail below) substantially on the valve 100, 100″ or on the tappet head 10 of the valve tappet rod 1 in an actuator chamber 221 of the housing 240 of the metering system 200. The metering system 200 shown in FIG. 6 further comprises a metering material storage holder 270 for holding an exchangeable metering material container and, as shown here, a heating device 250 mounted, for example, on the valve holder 212 of the fluid unit 211, or a heating module 250 having at least one heating connection cable 251. The metering material can thus be heated to the desired metering temperature during operation, as required. Relative directional indications such as “upper”, “lower”, “inner”, “outer”, “front side”, “rear side”, “longitudinal side”, etc. are used here arbitrarily to indicate the illustration in the figures.

[0089] The valves 100, 100" of the metering system 200 essentially serve to allow the supply or discharge of metered material in a metered manner by means of valve tappet rods 1, 1" which are moved by actuator units 220, as will be further explained below.

[0090] The overall structure of the valves 100, 100″ can be representatively described by the valve 100 as follows: the valve 100 has an elongated hollow cylindrical valve body 101 (the longitudinal direction here corresponds to the vertical direction in the drawing) or fitting 101 (represented by a dot), which here in FIG. 1 surrounds, at the top, a guide sleeve 105 (represented by a check), and at the bottom is formed as a funnel-shaped valve chamber 104 for metering material.

[0091] For this purpose, the valve body 101 is inserted into the circular opening of the already mentioned valve support 212 of the hydraulic unit 211 approximately to the height of the valve chamber 104 and is thus held in an upright position (here in the figure). As can be seen in FIG. 6, the valve body 101 is mounted or embedded laterally in the metering system 200 between two cylinder pins 225 in a guide cylinder 226. Here, the actuator spring 222f of the actuator unit 220 is arranged around the valve body 101 in the guide cylinder 226 so that the actuator spring 222f pushes the lever 223 of the actuator unit 220 upwards at the end where the lever 223 contacts the tappet 1. The manner of operation of the actuator unit 220 will be described in more detail below. This actuator unit 220 as a whole is also described in more detail in DE 10 2017 122 034 A1.

[0092] At this point, for the sake of completeness, it is pointed out that the weighing system 200 according to the invention is not limited to this orientation for weighing materials, and thus, for example, weighing in horizontal or other orientations (e.g. overhead) is also conceivable.

[0093] As already mentioned above, the valve tappet rod 1, also simply referred to as tappet 1 hereinafter, is located in a guide sleeve 105, which will be described in more detail below. Between the tappet head 10 of the tappet 1 (described further below) and the guide sleeve 105, a restoring element 120, which will also be described in more detail below, is arranged. Further down along the tappet 1 (in the direction of the tappet tip 60), approximately at the level of the valve support 212, a serpentine membrane seal 150m (see FIG. 1 ), as already mentioned as a sealing element 150, is arranged around the tappet 1 and between the guide sleeve 105 and the valve chamber 104 of the valve body 101, which will be described in more detail below.

[0094] As shown in detail in Figure 1, the hollow cylindrical or sleeve-like valve body 101 comprises an upper opening 101a on the tappet head side (here clearly above the valve support 212), a lower opening 101b on the tappet tip side (below the valve support 212), and in an intermediate region therebetween several open sight windows 103 in that part of the outer wall of the valve body 101 (the lower edges of the sight windows 103 are here located at the level of the upper edge of the valve support 212).

[0095] Between the upper and lower openings 101 a, 101 b, the inner diameter of the valve body 101 changes several times. Overall, the inner diameter decreases substantially in several steps from the upper opening 101 a, through which the guide sleeve 105 is introduced, to the upper edge of the sight window 103, and again from the lower edge of the sight window 103 (or the upper edge of the valve chamber 104) to the lower opening 101 b. Between them, in the region of the sight window 103, the inner diameter of the valve body 101 (or the inner cavity between the sight windows 103 in the outer wall) is continuously the same size.

[0096] Here, the area above the inner viewing window 103 in the valve body 101 is shaped so that the guide sleeve 105 lies in a threaded state after being screwed therein (as will be explained in more detail below) from above into a given position for the completed assembly of the valve 100. For this, the inner side of the wall of the valve body 101 has, in this area, at least one (internal) thread (or internal thread) into which the external thread (or (externally) threaded segment) 102 of the guide sleeve 105 (as will be explained in more detail below) is screwed, thus preventing relative longitudinal movement during operation.

[0097] Alternatively, the inside of the wall of the valve body 101 may have at least one step in this area into which a protrusion or bead of the guide sleeve 105 may be engaged or clicked to connect the two components together without rotational movement.

[0098] Separately from this, on the outside, approximately at the level of this inner thread, a valve body annular groove 101n is machined on the outside of the wall of the valve body 101, in which a typical O-ring 101o (or ring seal 101o) of the valve 100 (FIG. 6) is located in the completed assembled state of the valve 100 in the metering system 200. This ring seal 101o ensures that, in the assembled state, the plug connection of the hydraulic unit 211 is annularly sealed against the mating plug connection of the actuator unit 200, as disclosed in DE 102017122034 A1.

[0099] Below the viewing window 103, the interior of the valve body 101 forms, as already mentioned, the nozzle chamber (or valve chamber) 104. The valve chamber 104 has as its upper closure (or as a flat upper edge) a sealing edge 104t on which the sealing element 150 rests as membrane sides 150f, 150m. Further downwards, in the direction of the opening 101b in the valve body 101 on the tappet tip side, first extends the actual valve chamber 104. Above the step in the wall 104w of this valve chamber 104, which reduces the internal diameter, the already mentioned feed channel 180 opens into the valve chamber 104, through which the metered material is introduced into the valve chamber 104 during operation.

[0100] Below this step, in the last third of the valve chamber 104, a clamping edge 104k, which also reduces the inner diameter, projects flange-like into the valve chamber 104. Here, the narrowing of the inner diameter of the valve chamber 104 extends conically or funnel-like from above (and therefore becomes continuously narrower) towards this clamping edge 104k. In contrast, the clamping edge 104k coming from below constitutes a ledge (or right-angled step) that suddenly becomes wider partway along the inner wall or wall 104w of the valve chamber 104. This step or clamping edge 104k serves as a stop for the nozzle 111 (or an inserted nozzle insert 111), as will be explained below.

[0101] Outside, in the area below the step, the valve chamber 104 or valve body 101 is provided with an external thread 104g for tightly screwing a nozzle adjusting nut 110 thereon. The nozzle adjusting nut 110 is here a threadable hollow cylindrical sleeve with a central circular nozzle adjusting nut opening 110a that is smaller than the opening 101b in the valve body 101 on the tappet tip side. Here, the nozzle adjusting nut opening 110a is formed in the lower part of the nozzle adjusting nut 110, with a smaller bore diameter than in the upper part of the nozzle adjusting nut 110. The upper part of the nozzle adjusting nut 110 is further provided with an internal thread 110g that screws into the external thread 104g of the valve body 101 or valve chamber 104. Between the screwed-in nozzle adjusting nut 110 and the lower end of the valve chamber 104, more precisely, the right-angled clamping edge 104k of the valve chamber 104, a nozzle insert 111 (actual nozzle 111) is arranged, which is clamped to the valve chamber 104 when the nozzle adjusting nut 110 is screwed in. The nozzle insert 111 also has an opening (or nozzle opening) 111a formed therein. On its upper side, the nozzle insert 111 has a conical, downwardly tapering (or funnel-shaped) internal shape (as a valve seat 111d or sealing seat 111d for the tappet 1) to allow the metered material to flow, accelerate the discharge speed, and adjust the discharge amount (depending on the inserted nozzle insert 111). Thus, finer structures or shapes of the metered material may be metered onto the workpiece by the metering system 200.

[0102] 1, the guide sleeve 105 (marked with checks), already mentioned several times above, comprises in its longitudinal direction four regions for the tappet 1, which should be differentiated according to their function. In the end region arranged closer to the tappet head 10 of the tappet 1 during operation, the guide sleeve 105 is formed as a restoring element (or spring) holder 105a, i.e. the outer diameter of the spring holder 105a is at a minimum smaller than the inner diameter of the wound restoring element 120 (here in fact the associated coil spring 120) used for this purpose.

[0103] The return or spring stop 105b of the guide sleeve 105 adjoins the spring catch 105a, and the outer diameter of said stop is wider than that of the spring catch 105a above it. This outer diameter is, for example, wider precisely so that it terminates flush with the outer diameter of the coil spring 120.

[0104] The coil spring 120 is helical or "hollow cylindrical", as is common for such torsion or coil springs 120, and has at least the necessary spring force (as a restoring force) to balance the force of the actuator unit 220 of the weighing system 200.

[0105] The coil spring 120 in the completed assembled state is thus guided flush between the spring stop 105b and the tappet head 10 of the tappet 1, i.e. it is at least partially pressed on both sides against the bolt-like fasteners 10, 105b for the coil spring 120, in such a way that when viewed in the radial direction, the coil spring 120 terminates flush and without protrusions, as will be explained further in the context of assembly at the end. This arrangement of the coil spring 120 ensures that, after compression by the actuator 222 or lever 223 of the actuator unit 220, the coil spring 120 exerts the desired linear, opposing restoring force on the tappet 1 as intended, thereby providing that the tappet 1 automatically reaches or returns to its initial state again with a time lag after an impact of the actuator unit 220.

[0106] Here, the movement mechanism of the actuator 222 of the actuator unit 220 works as follows: the actuator 222 acts on the area of ​​the lever 223 of the actuator unit 220 and is mounted at its end in a lever bearing 224 so as to be rotatable about the tilt axis K. The impact of the actuator 222 acting on the lever 223 between the lever bearing 224 and the contact surface 223k of the lever 223 with the tappet head 10 can be displaced via the lever 223 and a space can be created above the tappet head 10.

[0107] At this point, for the sake of completeness, it is pointed out that the weighing system 200 according to the invention preferably comprises an actuator unit 220 having a piezoelectric actuator (e.g. a piezoelectric stack), but this does not exclude that a different actuator mechanism could also be used, such as, for example, a pneumatically driven actuator, etc.

[0108] Adjacent to the spring stop 105b of the guide sleeve 105 is a threaded region 105c, characterized by the fact that the guide sleeve 105 is connected, or screwed onto the valve body 101, or engaged or clicked into as described above, during installation in the valve body 101. To this end, the guide sleeve 105 comprises at least one connecting element, here in fact a threaded segment 102, i.e. a protruding threaded segment 102, which engages with a corresponding internal thread of the valve body 101.

[0109] Again, further downwards (in the direction of the nozzle 111), opposite the spring stop 105b, a hollow cylindrical region 105d adjoins the threaded region 105c of the guide sleeve 105. This hollow cylindrical region 105d is arranged at the lower end of the guide sleeve 105 and is characterized in that the major part of the diameter (seen in cross section) of the guide sleeve 105 is now recessed at the front, so that the guide sleeve 105 consists only of an outer annular hollow cylindrical wall therein and a cavity (or pre-chamber) is again arranged in the guide sleeve 105 on the nozzle side. In other words, in the hollow cylindrical region 105d, only annular wall sections of the guide sleeve 105 remain, which are further provided with advantageously radially extending drainage bores 107. These can basically be selected as desired with regard to their shape, for example, circular, elliptical, semicircular, angled, e.g., rhomboid, trapezoidal, star-shaped, triangular, etc., or elongated, such as a slit that wraps around at least partially around the circumference. The so-called drainage bores 107 simply refer to through-openings or outwardly continuous openings in the hollow cylindrical region 105d of the guide sleeve 105, through which, as the name already indicates, material (in this case, possibly metered material) can be guided away. They provide that metered material that has unintentionally reached the hollow cylindrical region 105d can also reach the outside again from the hollow cylindrical region 105d. How metered material can generally get into the hollow cylindrical region 105d of the guide sleeve 105 will be explained further below.

[0110] As for the remaining aforementioned regions 105a, 105b, 105c, on the other hand, it can be said that the front bore 106 passing longitudinally through these regions from the opening 106a on the tappet head side (here, at the upper end of the spring retainer 105a) to the opening 106b on the tappet tip side (at the upper end of the hollow cylindrical region 105d) has a continuously constant borehole inner diameter 106d that is significantly smaller than the aforementioned bore in the hollow cylindrical region 105d.

[0111] An advantage of a continuously constant bore 106 in the guide sleeve 105 is that the guide sleeve 105 is thereby easier to produce and can be manufactured from hard metal or another hard material, as shown in Figure 3. This provides that at least the inner guide sleeve portions 105a", 105b" in contact with the tappet 1 can be formed from a significantly more wear-resistant and more robust material, as will be explained further below.

[0112] Below the hollow cylindrical region 105d of the guide sleeve 105 is arranged the already mentioned sealing element 150, here actually formed as a serpentine membrane seal 150m in Figure 1. This "ring seal" seals around a portion of the tappet 1 and between the annular lower edge of the hollow cylindrical region 105d of the guide sleeve 105 and the annular upper edge (or sealing edge) 104t of the valve chamber 104.

[0113] The radially inner annular first sealing point 151 of the membrane seal 150f, 150m here seals against the tappet 1 by being undersized relative to the outer diameter 50d of the fluid part 50. Here, a fixed inner sleeve 150i may be arranged on this first sealing point 151 (here as part of the membrane seal 150m as shown in Figures 1 and 2), which is fixedly mounted in position within the membrane seal 150m by means of a tongue and groove joint. The inner sleeve 150i additionally has an inner diameter that abuts against the ledge 45 on the valve tappet rod 1, as will be further explained below.

[0114] A radially outer annular second sealing point 152 is located between the lower edge of the hollow cylindrical region 105d and the upper edge of the valve chamber 104. This second sealing point 152 is compressed from above and below during assembly of the guide sleeve 105 in the valve chamber 104, thus providing a continuous seal due to the (contact) pressure described above.

[0115] Between these two sealing points 151, 152, a flexible and / or elastic transition area 153 or membrane 153 ensures that the membrane seals 150f, 150m seal the valve chamber upward against the guide sleeve 105 as intended, thus preventing metering material from reaching into the hollow cylindrical area 150d of the guide sleeve 105, as the case may be.

[0116] Nevertheless, if the metered material were to reach upwards through the membrane seals 150f, 150m, for example in the event of a seal failure, the already mentioned drainage bore 107 in the hollow cylindrical region 105d provides that the metered material reaches an area visible to the user, where it is visually noticed by the viewing window 103 (for example directly by the user or via a user camera). In order to give the user more time to be able to quickly reveal this malfunction, moreover, there is a particularly large amount of space in the hollow cylindrical region 150d to be able to accommodate the metered material flowing out of the valve chamber 104 for as long as possible in the event of a possible seal failure.

[0117] Furthermore, because they are somewhat spaced apart from one another, additional metered material collects between the outside of the radially outer sealing point 152 of the membrane seal 150f, 150m and the wall adjacent to the outside of the valve chamber 104. This space thus defines a kind of cavity or collection area 104s below and outside the guide sleeve 105 or drainage bore 107. Only if this collection area 104s further overflows will metered material flow out of the viewing window 103. The user therefore has more time to visually reveal a seal failure by looking into the viewing window 103 before overflowing actually occurs. They can then prepare for replacement of the valve 100, 100″ before the overflowing metered material can reach the area of ​​the workpiece that should be kept clean.

[0118] The somewhat flat membrane seal 150f shown in FIG. 2 is further shaped so that the metered material first collects on the membrane seal 150f before flowing out through the drainage bore 107.

[0119] During normal operation, this spacing or material gap through the viewing window 103 and the drainage bore 107, however, additionally has a further primary function: it provides thermal insulation so that heat conduction or heat exchange into the areas 105a, 105b, 105c, 105d located above it is reduced, for example in the case of heated or cooled metering material, or conversely, for example in the case of a particularly heated actuator below.

[0120] With the aid of FIG. 4, a first preferred exemplary embodiment of a valve tappet rod 1 or tappet 1 according to the invention will now be described, as it can be used in the exemplary embodiment according to FIG.

[0121] As can be seen from the isolated view of the tappet 1 in Figure 4, the tappet 1 relates to an elongated (cylindrical) body having a longitudinal axis LA in the longitudinal direction of the body. Along the longitudinal axis LA, the tappet 1 comprises a plurality of sections 10, 20, 30, 40, 50, 55, 60 of different lengths, which differ from one another, in particular, in their width in the direction perpendicular to the longitudinal axis LA, or in their outer diameters 11d, 13d, 20d, 30d, 40d, 50d or in their radius 60r.

[0122] The tappet 1 is formed with a tappet head 10 in an upper head region A and a tappet tip 60 at an opposite lower end B, longitudinally spaced therefrom along the longitudinal axis LA. Between the tappet head 10 and the tappet tip 60 of the tappet 1 are arranged portions 20, 30, 40, 50, 55 formed with preferred lengths 20l, 30l, 40l, 50l, 55l, respectively. Overall, the tappet 1 therefore has a total length 1l here, corresponding to the sum of the lengths 10l, 20l, 30l, 40l, 50l, 55l. The length of the tappet tip 60 is to be ignored here.

[0123] The first guide sleeve part 20 adjoins the tappet head 10. Adjacent to this is in turn the narrow section 30, which is followed by the second guide sleeve part 40. Adjacent to that is the fluid section 50 and then the tappet tip part 55, which adjoins directly at the end with the tappet tip 60.

[0124] The tappet head 10 here extends in the longitudinal direction LA through two parts 11, 13: the actuating flange 11 (on the surface side, as the end of the head region A) and the guide ledge 13, which continues over a short, thinned transition 14 (or section) towards the first guide sleeve part 20. The two parts 11, 13 differ substantially from each other in their outer diameters 11d, 13d. The outer diameter 11d of the actuating flange 11 here is larger than the outer diameter 13d of the guide ledge 13. During operation, the actuating flange 11 of the tappet 1 serves as an attack point for the actuating member or lever 223 of the actuator unit 220 (see FIG. 6). Here, the actuating flange 11 is in at least temporary contact with the contact surface 223k of the lever 223. At the same time, the larger outer diameter 11d of the actuation flange 11 provides that the coil spring 120 bears upwards against the tappet 1 when it is brought into its operating position in the tappet head 10. The outer diameter 13d of the guide ledge 13 is here selected so that the helical coil spring 120 is guided inwardly through the guide ledge 13, i.e. the inner diameter of the coil spring 120 is large enough that it just fits into the guide ledge 13.

[0125] The aforementioned transition 14 from the guide ledge 13 to the first guide sleeve part 20 is formed in the form of a fillet. The outer diameter 20d of the first guide sleeve part 20 is therefore smaller than the outer diameter 13d of the guide ledge 13. At the lower end of the first guide sleeve part 20, a sharp, relatively steep ledge 25 is formed up to the narrow part 30, the outer diameter 30d of which is again smaller than the outer diameter of the first guide sleeve part 20. This ledge 25 is short and "steep" relative to the transition 35 at the lower end of the narrow part 30 to the second guide sleeve part 40. This transition 35 can therefore be described rather as a "flat ramp" or slope that is relatively long and has a barely noticeable gradient.

[0126] The lower end of the second guide sleeve part 40 is now also formed with a sharp ledge 45, or fillet 45. This fillet 45 preferably has a fillet radius 45r of at least 0.01 mm, particularly preferably at least 0.1 mm, and most particularly preferably at least 0.25 mm. This ensures that the already mentioned inner sleeve 150i of the membrane seal 150f, 150m is held in place particularly well along the tappet 1 during the discharge movement (downward) of the tappet 1 in operation in the valve 100 of the metering system 200. This is because the inner sleeve 150i rests with its inner edge directly against the tappet 1 in the upper end region of the fluid part 50, so that the inner sleeve 150i and the membrane seal 150m are moved in the intended direction of discharge past the ledge 45 during the discharge movement of the tappet 1.

[0127] At its lower end, the fluid section 50 extends almost smoothly to a tappet tip 55 near the tappet tip 60. The tappet tip 55 of the tappet 1 tapers conically to the tappet tip 60. As already mentioned, the end A of the tappet 10 forms the rounded tappet tip 60, which here has a radius 60r of R 0.20 mm in FIG. 4 (with a tolerance of ±0.01 mm so that equivalent results can be achieved later with a new part when replacing a defective part). This radius 60r is here, by way of example, adapted to the nozzle 111 of the valve 100. In general, however, an exact adaptation of the radius 60r to the nozzle 111 of the valve 100 is not necessary. Different size combinations are also conceivable, e.g., a smaller radius of the tappet tip 60 with a larger nozzle cross-section.

[0128] In this respect, it is pointed out that the radius 60r within the scope of the present invention may vary from a particularly small radius, and therefore almost "point-like", to a somewhat larger radius 60r, i.e., larger than, for example, the diameter 30d, 50d of the valve tappet rod 1.

[0129] The individual portions 10, 20, 30, 40, 50, 55, 60 of the tappet 1 differ, on the one hand, in their length along the longitudinal axis LA, and, on the other hand, in their width in the direction perpendicular to the longitudinal axis LA, or in their outer diameter, but otherwise they have no substantially characterizing features.

[0130] As shown in FIG. 4, in a first variant of the first preferred exemplary embodiment of the tappet 1, the portions 10, 20, 30, 40, 50, 55 of the tappet 1 may be formed with the following lengths 10l, 20l, 30l, 40l, 50l, 55l:

[0131] The tappet head 10 preferably has a length 10l of about 2 mm, the first guide sleeve portion 20 has a length 20l of about 3.5 mm, the narrow portion 30 has a length 30l of about 16 mm, the second guide sleeve portion 40 has a length 40l of about 5 mm, the fluid portion 50 has a length 50l of about 13.7 mm, and the tappet tip portion 55 (together with the tappet tip 60) has a length 55l of about 3 mm. The tappet 1 therefore has a preferred overall length 1l of about 43.2 mm.

[0132] However, in a second variant of the first preferred exemplary embodiment of the tappet 1, the portions 10, 20, 30, 40, 50, 55 of the tappet 1 may also be formed with the following lengths: 10l, 20l, 30l, 40l, 50l, 55l:

[0133] Preferably, the tappet head 10 has a length 10l of approximately 2 mm, the first guide sleeve portion 20 has a length 20l of approximately 3.5 mm, the narrow portion 30 has a length 30l of approximately 10 mm, the second guide sleeve portion 40 has a length 40l of approximately 5 mm, the fluid portion 50 has a length 50l of approximately 19.7 mm, and the tappet tip portion 55 (together with the tappet tip 60) has a length 55l of approximately 3 mm. This tappet 1 thus likewise has a preferred overall length 1l of approximately 43.2 mm. In this variant, however, the second guide sleeve portion 40 is arranged offset or displaced by approximately 6 mm towards the tappet head 10, so that the narrow portion 30 is approximately 6 mm shorter and the fluid portion 50 is therefore approximately 6 mm longer.

[0134] In the second particularly preferred exemplary embodiment of the tappet 1" according to FIG. 5, the lengths 30l", 50l", 55l" of the sections 30, 50, 55 are shorter, and only the length 40l" of the section 40 is somewhat longer. The tappet 1" is therefore, however, shorter overall.

[0135] Particularly preferably, the tappet head 10 has a length 10l" of approximately 2 mm, the first guide sleeve portion 20 has a length 20l" of approximately 3.5 mm, the narrow portion 30 has a length 30l" of approximately 10 mm, the second guide sleeve portion 40 has a length 40l" of approximately 5.95 mm, and the fluid portion 50, tappet tip portion 55 and tappet tip 60 have lengths 50l", 55l", 60r of approximately 11.7 mm. This tappet l" therefore has a particularly preferred overall length 1l" of approximately 33.2 mm.

[0136] This overall shorter tappet 1" is perfectly suitable for use, for example, in a valve 100" of a metering system 200 as shown in FIG.

[0137] A particularly preferred exemplary embodiment, also shown only in part, of a metering system 200 according to the invention with a second exemplary embodiment of a valve tappet rod 1" according to the invention, in turn also shows, by way of example, a valve 100" in which a serpentine membrane seal 150m is installed as sealing element 150. However, as shown in FIG. 2, a flat membrane seal 150f can also be used.

[0138] Such a metering system 200, such as that of Figure 3, is recommended when it is not desired to discharge any metered material that must be heated or warmed before metering. The tappet 1" or valve 100" can then be made shorter, since there is no heating unit that must be present in the metering system 200, which must be positioned at a specific distance relative to the tappet tip 60.

[0139] In contrast to the exemplary embodiment above, the body of the valve 100" for the metering system 200 is therefore here shorter.

[0140] As a more specific feature, the guide sleeve 105" already mentioned above now consists of inner guide sleeve portions 105a", 105b" and outer guide sleeve portions 105c", 105d". The inner guide sleeve portions 105a", 105b" have a shape that is very easy to produce and can be relatively advantageously produced from a more robust substance (or material) that wears less rapidly in the case of continuous stress (along the bore 103). For example, the inner guide sleeve portions 105a", 105b" can be made of, for example, hard metal, ceramic, zirconium oxide, silicon oxide, etc. , silicon nitride or silicon carbide, and the outer guide sleeve parts 105c", 105d" can be manufactured from a softer and more economical material, such as stainless steel, since they are not exposed to any abnormal stresses. The two guide sleeve parts 105a", 105b", 105c", 105d" (consisting of the spring seat 105a", the spring stop 105b", the threaded region 105c" and the hollow cylindrical region 105d") can preferably be connected to each other by pressing, gluing or in a further joining process.

[0141] The hollow cylindrical region 105d" of the guide sleeve 105" differs slightly from the hollow cylindrical region 105d of the guide sleeve 105. The hollow cylindrical region 105d" is rather represented as a kind of "hollow spherical region", and its drainage bore 107" can be significantly smaller thanks to the shorter valve body 101". Instead, an overall, but smaller, drainage bore 107" is present in order to be able to direct as much metered material away as possible.

[0142] In a direction perpendicular to the longitudinal axis LA of the tappet 1, 1", i.e. in the transverse or radial direction, there are the following preferred outer diameters 11d, 11d", 13d, 13d", 20d, 20d", 30d, 30d", 40d, 40d", 50d, 50d", or radii 60r, 60r", for the individual portions 10, 20, 30, 40, 50, 60 of the two exemplary embodiments of the tappet 1, 1".

[0143] The operating flange 11 of the tappet head 10 preferably has an outer diameter 11d, 11d" of approximately 4.6 mm, the guide portion 13 of the tappet head 10 has an outer diameter 13d, 13d" of approximately 3.15 mm, the first guide sleeve portion 20 has an outer diameter 20d, 20d" of approximately 1.7 mm, the narrow portion 30 has an outer diameter 30d, 30d" of approximately 1.5 mm, the second guide sleeve portion 40 has an outer diameter 40d, 40d" of approximately 1.7 mm, the fluid portion 50 has an outer diameter 50d, 50d" of approximately 1.5 mm, the tappet tip 60 has a radius 60r of approximately 0.2 mm, and the tappet tip 60 of the second exemplary embodiment of tappet 1" has a radius 60r" of approximately 0.35 mm.

[0144] All components of the exemplary embodiments of the metering system 200 according to the invention or of the valve 100, 100" according to the invention can be replaced separately by the user in the field, i.e. disassembled and reassembled in the manner of a modular system.

[0145] When mounting the tappets 1, 1" in the valves 100, 100" in the metering system 200, first the coil spring 120 is pressed onto the tappet 1, 1" from the tappet tip 60 onto the tappet head 10. Then (also starting from the tappet tip 60) the guide sleeve 105, 105" is pressed onto the tappet 1, 1" so that the coil spring 120 slides over the spring seat 105a, 105a" and is guided between the tappet head 10 and the spring stop 105b, 105b". This allows the inner sleeve 150i to slide over the flat tappet head 10, 105a, 105a" into which the inner sleeve 150i has already been inserted. The membrane seal 150f (or serpentine membrane seal 150m) is pressed against the tappet 1, 1" (again, starting from the tappet tip 60) until it abuts the hollow cylindrical region 105d, 105d" of the guide sleeve 105. The just-assembled components are then inserted from above into the opening 101a of the valve body 101, 101" of the valve 100, 100" and screwed in. The completed assembled valve 100, 100" is thereby installed in the corresponding position in the metering system 200, as can be seen in Figure 6. For this, the valve 100, 100" is inserted into a holding position in the metering system 200 between two cylinder pins 225, or the actuator spring 222f into the guide cylinder 226 of the actuator unit 220.

[0146] Finally, it is pointed out once again that the device described in detail above only relates to an exemplary embodiment that can be modified in various ways by those skilled in the art without departing from the scope of the present invention. Therefore, other restoring or sealing elements, such as ring seals, etc., also fall within the scope of the present invention. Furthermore, the use of the indefinite articles "a" or "an" does not exclude that each feature may be present several times. Similarly, the terms "arrangement," "element," "module," and "system" do not exclude that each component may consist of several interacting subcomponents, possibly spatially distributed. [Explanation of symbols]

[0147] 1.1" valve tappet rod 1l, 1l" valve tappet rod overall length 10 Tappet Head 10l, 10l” tappet head length 1l Actuation flange 1ld, 11d" Operating flange outer diameter 12 Transition / Fillet 13 Guide Ledge 13d, 13d" guide ledge outer diameter 14 Transition / Fillet 20 first guide sleeve portion 20d, 20d" Outer diameter of first guide sleeve part 20l, 20l” Length of first guide sleeve section 25 Ledge 30 Narrow part 30d, 30d” Narrow outer diameter 30l, 30l” Narrow section length 35 Transition 40 second guide sleeve portion 40d, 40d" Outer diameter of second guide sleeve 40l, 40l” Second guide sleeve length 45 Ledge / Fillet 45r fillet radius 50 Fluid Section 50d, 50d" Fluid Outer Diameter 50l, 50l” fluid length 55 Tappet tip 55l, 55l” Tappet tip length 60 Tappet tip 60r, 60r” Tappet tip radius 100, 100" valve 101, 101" Valve Body / Fitting 101a Valve body opening, tappet head side 101b Valve body opening, tappet tip side 101n Valve body annular groove 101o Seal / O-ring 102 screw segments 103, 103" valve body sight window 104, 104" Valve chamber of valve body 104g external thread 104k clamping edge 104s Collection Area 104t Seal Edge 104w, 104w” Valve chamber wall 105, 105" guide sleeve 105a, 105a” Guide sleeve spring holder 105b, 105b” Guide sleeve spring stop 105c, 105c” Guide sleeve thread area 105d, 105d” Hollow cylindrical area of ​​guide sleeve 106 Guide sleeve bore 106a Opening, tappet head side 106b Opening, tappet tip side 106d Borehole inner diameter / Inner diameter of bore 107, 107" drainage bore 110 Nozzle adjustment nut 110a Nozzle adjustment nut opening 110g internal thread 111 Nozzle / Nozzle Insert 111a nozzle opening 111d Valve seat / sealing seat 120 restoring element / coil spring 150 sealing elements / membrane seals 150m membrane seal, serpentine 150f membrane seal, flat 150i Serpentine Membrane Seal Inner Sleeve 151 First sealing point 152 Second sealing point 153 Transition Region / Membrane 180 Supply Channels 200 Weighing System 211 Fluid Unit / Bayonet Type Fluid Section 212 Valve support 220 Actuator Unit 221 Actuator Chamber 222 Actuator 222f Actuator Spring 223 Lever 223k contact surface 224 Lever bearing 225 Cylinder pin 226 Guided cylinder 240 Housing 250 Heating Device / Heating Module 251 Heating Connection 270 Weighing material storage holder A Valve tappet rod head area B Valve tappet rod end, front side LA Longitudinal axis of valve tappet rod

Claims

1. A valve tappet rod (1, 1") for a valve (100, 100") of a metering system (200) for metering material, comprising: The valve tappet rod (1, 1 ″) The tappet tip (60) is at the front end (B), A tappet head (10) is provided on the opposite side in the head area (A), and The valve has an elongated, generally cylindrical body between the tappet head (10) and the tappet tip (60), and has at least a first guide sleeve portion (20), a narrow portion (30), a second guide sleeve portion (40), and a fluid portion (50) formed from the tappet head (10) to the tappet tip (60), the outer diameter (30d, 30d") of the narrowed portion (30) is reduced compared to the outer diameter (20d, 20d", 40d, 40d") of the guide sleeve portion (20, 40); A valve tappet rod (1, 1"), wherein a ledge (45) is formed in the shape of a shoulder to hold a sealing element (150f, 150m) in place between the second guide sleeve portion (40) and the fluid portion (50).

2. 2. The valve tappet rod according to claim 1, wherein the outer diameters (20d, 20d", 40d, 40d") of the guide sleeve portions (20, 40) are equal in size, and / or the outer diameter (30d, 30d") of the narrow portion (30) is approximately the same in size as the outer diameter (50d, 50d") of the fluid portion (50).

3. 3. Valve tappet rod according to claim 1 or 2, wherein the tappet head (10) has an actuation flange (11) for an actuator unit (220) of the metering system (200).

4. 4. A valve tappet rod according to claim 3, wherein the tappet head (10) has a guide ledge (13) for centered guidance of a restoring element (120).

5. 5. The valve tappet rod according to claim 4, wherein an outer diameter (13d, 13d") of the guide ledge (13) is larger than the outer diameter (20d, 20d") of the first guide sleeve portion (20), and an outer diameter (11d, 11d") of the operating flange (11) is larger than the outer diameter (13d, 13d") of the guide ledge (13).

6. 6. A valve tappet rod according to claim 1, wherein a ledge (25) between the first guide sleeve portion (20) and the narrow portion (30) is formed to be steeper than a transition (35) between the narrow portion (30) and the second guide sleeve portion (40).

7. The valve tappet rod according to any one of claims 1 to 6, wherein the fluid portion (50) has an outer diameter (50d, 50d") smaller than the outer diameter (40d, 40d") of the second guide sleeve portion (40).

8. 2. A valve tappet rod according to claim 1, wherein the ledge (45) is shoulder-shaped as a fillet (45).

9. 9. A valve tappet rod according to claim 8, wherein the fillet (45) has a fillet radius (45r) of at least 0.01 mm and / or a fillet radius (45r) of at most 2 mm.

10. the tappet tip (55) adjacent to said tappet tip (60) has a length (55l, 55l") of at least 0.25 mm and / or a length (55l, 55l") of at most 10 mm; and / or the tappet head (10) has a length of at least 0.25 mm (10l, 10l") and / or a length of at most 10 mm (10l, 10l"), and / or the first guide sleeve portion (20) has a length (20l, 20l") of at least 1 mm and / or a length (20l, 20l") of at most 20 mm, and / or the second guide sleeve portion (40) has a length (40l, 40l") of at least 1 mm and / or a length (40l, 40l") of at most 20 mm, and / or the narrowed portion (30) has a length (30l, 30l") of at least 1 mm and / or a length (30l, 30l") of at most 25 mm, and / or Valve tappet rod according to any one of claims 1 to 9, wherein the fluid portion (50) has a length of at least 1 mm (50l, 50l") and / or a length of at most 50 mm (50l, 50l")

11. The tappet tip (60) has a radius (60r, 60r") of at least 0.1 mm and / or a radius (60r, 60r") of at most 0.8 mm, and / or The working flange (11) of the tappet head (10) has an outer diameter (11d, 11d") of at least 3.2 mm and / or an outer diameter (11d, 11d") of at most 10 mm, and the guide ledge (13) of the tappet head (10) has an outer diameter (13d, 13d") of at least 1.75 mm and / or an outer diameter (13d, 13d") of at most 9 mm; and / or the first guide sleeve portion (20) has an outer diameter (20d, 20d") of at least 1.55 mm and / or an outer diameter (20d, 20d") of at most 2.9 mm; and / or the second guide sleeve portion (40) has an outer diameter (40d, 40d") of at least 1.55 mm and / or an outer diameter (40d, 40d") of at most 2.9 mm; and / or The narrow portion (30) has an outer diameter (30d, 30d") of at least 1 mm and / or an outer diameter (30d, 30d") of at most 3 mm, and / or A valve tappet rod according to any one of claims 1 to 10, wherein the fluid portion (50) has an outer diameter (50d, 50d") of at least 0.5 mm and / or an outer diameter (50d, 50d") of at most 3 mm.

12. A valve (100, 100") for a metering system (200) for metering materials, comprising a valve tappet rod (1, 1") according to any one of claims 1 to 11.

13. The valve (100, 100") has at least a generally hollow cylindrical valve body (101, 101") surrounding a guide sleeve (105, 105"), wherein during intended operation at least the guide sleeve portion (20, 40) remains partially within the guide sleeve (105, 105") and the narrow portion (30) of the valve tappet rod (1, 1") entirely within the guide sleeve (105, 105"); a valve chamber (104, 104") for receiving the metered material in a lower region of the valve body (101, 101") on the side facing away from the tappet head (10); a sealing element (150f, 150m) for sealing between the guide sleeve (105, 105") and the valve chamber (104, 104") of the valve body (101, 101"); The valve of claim 12, comprising:

14. The valve (100, 100") has at least a restoring element (120) mounted between the tappet head (10) of the valve tappet rod (1, 1") and the guide sleeve (105, 105") for the valve tappet rod (1, 1"); and / or a sealing element (150f, 150m) formed as a serpentine membrane seal (150m) or a flat membrane seal (150f); 14. The valve of claim 13, comprising:

15. 15. A valve according to claim 13 or 14, comprising a conically tapering tappet tip (55) of the valve tappet rod (1) between the tappet tip (60) and the fluid part (50) and adjacent to the tappet tip (60), wherein a length (55l, 55l") of the tappet tip (55) for an associated nozzle (111) of the valve (100) varies depending on the radius (60r, 60r") of the tappet tip (60) and / or the length (55l, 55l") of the tappet tip (55) for the associated nozzle (111) is a maximum of 3 mm.

16. Valve according to any one of claims 13 to 15, wherein the guide sleeve (105, 105") is at least partly made of a hard material and / or of at least two parts, of a metal matrix composite material with hard material particles.

17. A valve according to any one of claims 13 to 16, wherein the guide sleeve (105, 105") is at least partly made of hard metal.

18. Valve according to any one of claims 13 to 17, wherein the guide sleeve (105, 105") is made at least partly of a hard material, that is a metal matrix composite having hard material particles.

19. A metering system (200) comprising a valve (100, 100") according to any one of claims 12 to 18 or at least a valve tappet rod (1, 1") according to any one of claims 1 to 11, a supply channel (180) for the metered material; and an actuator unit (220) for actuation of the valve tappet rod (1, 1"), exerting a stroke having a maximum stroke length of 1 mm, directly or indirectly on the tappet head (10); A weighing system (200) comprising:

20. 20. The weighing system of claim 19, comprising a weighed material storage holder (270) for holding a weighed material container.

21. 21. A metering system according to claim 19 or 20, wherein the length (20l, 20l", 40l, 40l") of each guide sleeve portion (20, 40) of the valve tappet rod (1, 1") corresponds at least to the stroke length of the valve tappet rod (1, 1").

22. A metering system (200) having a valve (100, 100") according to any one of claims 13 to 18, comprising a supply channel (180) for metered material and an actuator unit (220) for actuation of the valve tappet rod (1, 1"), directly or indirectly acting on the tappet head (10), with a stroke having a maximum stroke length of 1 mm, 1. A metering system, wherein the narrow portion (30) of the valve tappet rod (1, 1") is shorter than the associated guide sleeve (105) of the valve (100, 100") by at least twice the maximum stroke length of the valve tappet rod (1, 1").

23. 12. Use of a valve tappet rod (1, 1 ") according to any one of claims 1 to 11, having at least one narrow portion (30) surrounded by two guide sleeve portions (20, 40) as a lubricant reservoir for automatic lubrication of the valve tappet rod (1, 1 ") during operation of the valve tappet rod (1, 1 ") during its intended discharge and retraction movements.

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