EP4067651B1 - Chamber dosing valve, metering system for same and method for dispensing a viscous medium - Google Patents

Description

The present invention relates to a chamber dosing valve for the metered dispensing of a viscous medium according to the preamble of claim 1, an associated dosing system and a method for the metered dispensing of a viscous medium according to the preamble of claim 15. In particular, the invention relates to a chamber dosing valve and a method for the finely metered dispensing of a viscous medium in small quantities, such as the dispensing of lubricants, adhesives, sealants and the like.

Technical area

In mechanical, automation, and process engineering, the application and dosing of various process media is required with the greatest possible precision, localization, and coverage. These media are characterized by very different physical and chemical properties.

The process media to be dosed include, for example, oils, varnishes, lubricants such as greases, resins, silicones, adhesives, sealants, gels, pastes, liquid polymers, casting compounds and pasty substances used in pharmaceutical, food technology or general industrial processing.

The media to be dosed and the user scenarios are characterized by a wide variety of parameters, resulting, for example, from the variety of applications, the characteristic material properties of the media to be applied, their supply, the prevailing media and ambient conditions during storage and application (e.g., temperature and humidity), the applied and required process pressures, the chemical reaction behavior and the potential corrosive effects of the media, and above all, their viscosity. Further complicating factors are the requirement to supply the media with repeatable accuracy and as uninterruptedly as possible in a wide variety of quantities or volumes, in a controlled and finely dosed manner.

State of the art

Various solutions for dosing systems – generally referred to as dosing valves or dosing units – are known from the state of the art, which can handle fluids of different types apply from one or more existing components.

Dosing systems for small-volume dosing of liquids and media of low viscosity are known. These are designed as syringe-like, single-chamber systems in various sizes, flow rates, and implementations. The mostly liquid dosing materials are applied with pinpoint accuracy via a longitudinal movement of a piston, for example, via hollow needles. Such dosing systems are known and used primarily in process engineering equipment, for the controlled filling of mostly liquid media and mixtures into special containers. Their application environment is determined, for example, by the requirements of filling technology, process-engineering media supply, or use in a laboratory environment.

The application area is being expanded with the use of comparable single-chamber systems in assembly technology, which also allows for the application of small quantities of various process media, some of which have higher viscosity. Current representative examples include syringe and small-quantity dosing in electrical and electronic encapsulation, the application of oily lubricants, and the application of reactants and process media in adhesive and sealing technology.

Such single-chamber dosing systems comprise, for example, a dosing unit and a drive unit that are connected to apply a medium from the dosing unit. The dosing unit comprises at least one media inlet, through which the medium is supplied to the dosing unit under pressure, and a media outlet, via which the medium is discharged from the dosing unit. The dosing unit has a media chamber with a media inlet and a media outlet, through which the medium enters the chamber and is discharged again from it. The media chamber comprises a dosing piston that is movable by means of the drive unit between a backward movement, during which the medium enters the chamber, and an advancing movement to discharge the medium through the media outlet.

Dosing systems based on single-chamber systems are characterized primarily by the simplicity of their design and the resulting robustness in the application environment. The dimensional design of the chambers and the easily controllable linear movement of the pistons result in a very simple and repeatable medium dispensing option, although the dispensed quantities are limited. The inherent disadvantage of the limitation in these implementations relates to both the total quantity and The continuous supply of the medium is also important. The use of such dosing systems does not allow for the conveyance of highly viscous media and requires pauses for refilling the process chambers.

As mentioned above, in known chamber dosing systems, a piston similar to a syringe is pulled, which sucks the lubricant into the chamber, and pressing the piston expels the lubricant. This has the advantage that dosing can take place independently of pressure. However, as briefly mentioned above, the disadvantage is that even with larger chamber volumes, the lubricant must be refilled, which means an interruption of approximately 30 seconds in the process. If, for example, a part needs to be moistened with lubricant in a manufacturing process, the production process must be interrupted for the corresponding loading time to load the chamber dosing valve. For example, one cycle must be interrupted every 10 cycles to reload the lubricant into the chamber. A further disadvantage of the chamber dosing valve is that continuous lubricating grease dispensing is not possible due to the loading process. Longer lubricant distances, for example the application of lubricant beads, are therefore impossible.

Another system known in the prior art is a dispenser that operates in the manner of an extruder. This system is not suitable for less viscous media, as it would otherwise operate very imprecisely. Furthermore, the system is very pressure-sensitive and can only be used at a maximum of 15 bar. Furthermore, the stator is susceptible to wear. However, unlike the conventional chamber-type metering valves, the dispenser allows for continuous and uniform dispensing of lubricating grease (subject to the limitations described above).

US 2018/0030966 A1 describes a dispensing device for a grease gun. The dispensing head has two plungers that are alternately moved back and forth by a single cam member and two opposing coil springs, thereby feeding the grease from the reservoir to the hose of the grease gun. The cam member rotates around a rotation axis that runs parallel to the longitudinal axes of the plungers. The drive must be arranged longitudinally accordingly, so the device is quite large.

Task

It is an object of the present invention to improve known chamber metering valves in such a way that a low-pulsation, preferably uninterrupted application of Media of varying viscosity can be delivered continuously, and the system is relatively small. A further objective is to provide a method for the metered delivery of a viscous medium, with the delivery being able to occur continuously and with low pulsation.

Description of the invention

The object of the invention is achieved by a chamber metering valve for the metered dispensing of a viscous medium according to claim 1, a metering system according to claim 13, and a method for the metered dispensing of a viscous medium according to claim 15. Advantageous embodiments and further developments can be found in the dependent claims.

A chamber metering valve for the metered dispensing of a viscous medium according to the present invention comprises a metering unit and a drive unit that are connected to one another. The metering unit has at least one media inlet, at which the medium is supplied to the metering unit under pressure. The metering unit also has a media outlet, via which the medium is dispensed from the chamber metering valve. The metering unit further has a first media chamber that includes a media inlet and a media outlet, as well as a metering needle. The metering needle is movable in an oscillating manner between a forward movement, referred to as a metering position, and a backward movement, referred to as a loading position. During the backward movement of the metering needle, the medium is pressed into the media chamber due to the pressure applied to the media inlet. During a forward movement, the medium is discharged from the media chamber via the media outlet.

The dosing unit further comprises at least one second media chamber with a media inlet, a media outlet, and a dosing needle. The media outlets of the first and the at least one second media chamber open into the media outlet of the dosing unit. Advantageously, only a single common media outlet is present, which is connected to the media outlets of the media chambers. The first and second media chambers are preferably structurally identical, but their designs may differ depending on the specific structural requirements of the chamber dosing valve.

According to the invention, each of the dosing needles of the media chambers is coupled to a cam disk arranged on a common rotation axis. Thus, at least two cam disks are provided—in the case of a two-chamber dosing valve. Accordingly, more chambers and thus more cam discs are present in chamber dosing valves with more than two chambers, such as three chambers with three cam discs on a common rotation axis in a three-chamber dosing valve. The rotation axis is coupled to the drive unit, so that when the rotation axis rotates, the dosing needles, via their coupling to the respective cam disc, can each oscillate between the forward movement (the dosing position) and the backward movement (the loading position). The at least two cam discs are shaped and arranged offset from one another on the rotation axis such that essentially a forward movement of a first dosing needle occurs while a backward movement of a second dosing needle occurs, so that a continuous discharge of the medium from the chamber dosing valve takes place. Thus, the forward movements of the first and second media chamber alternate, and at any time during the dosing process, medium is pressed from one of the media chambers for discharge from the chamber dosing valve into the media outlet - dosing takes place continuously.

A two-chamber system will be described below as a possible example of the invention. However, as already briefly mentioned above, the metering valve according to the invention can also have more than two chambers. Those skilled in the art will be able to adapt the device accordingly and, for example, arrange the cam discs offset by 120° on the rotation axis, instead of a 180° offset arrangement in a two-chamber system.

The chamber dosing valve can advantageously be designed in a modular manner, with the drive unit forming a first module and the dosing unit forming a second module, for example. All components of the dosing unit, such as the at least two media chambers with the associated dosing needles, the media inlet, the media outlet, the rotation axis with the cam discs, etc., can be housed in a single modular element, for example.

Furthermore, the present invention provides a method for the continuous and low-pulsation dosing of a viscous medium using a chamber dosing valve. A chamber dosing valve as described above can advantageously be used to implement the method.

In the method according to the invention, the medium is supplied to the chamber metering valve under pressure via a delivery unit. For this purpose, an inlet pressure of at least 10 bar (1 MPa) to a maximum of 50 bar (5 MPa) can be used. The chamber metering valve contains a medium chamber with a metering needle, which between a forward movement as the dosing position and a backward movement as the loading position. During the backward movement of the dosing needle, the delivery unit pushes the medium through a media inlet into the media chamber, and during the forward movement, the dosing needle pushes the medium through a media outlet from the media chamber into a media outlet of the chamber dosing valve, through which the medium leaves the chamber dosing valve.

According to the invention, at least two media chambers are provided, the dosing needles of which are each moved between the dosing position and the loading position via a rotating cam disk, for which purpose the cam disks are arranged on a common axis of rotation. The cam disks are shaped and arranged offset from one another on the axis of rotation such that the dosing position of the first dosing needle essentially alternates with the dosing position of the second dosing needle, and a first dosing needle executes a forward movement while a second dosing needle executes a reverse movement. Due to such an opposing movement of the dosing needles, medium is pressed from one of the media chambers into the media outlet at any time during the dosing process, whereby the medium is dosed continuously and with little pulsation from the chamber dosing valve.

To carry out the oscillating movement of the dispensing needles between a forward and a backward movement, or between a dispensing position and a loading position, the cam discs are designed, for example, as eccentrics. If the at least two media chambers are arranged parallel to one another, these eccentrics can, for example, be arranged rotated relative to one another on the axis of rotation in order to enable the forward movement of a first dispensing needle to alternate with the forward movement of a second dispensing needle. The offset of the cam disc along the axis of rotation results from the structural distance between the dispensing needles or the media chambers. By coupling the dispensing needle to a circumferential contour of the cam discs and the eccentric mounting of the cam discs, the rotational movement of the cam discs is converted into a linear movement of the dispensing needles and the at least two dispensing needles can be moved back and forth in the media chambers in a coordinated manner. By coordinating the media delivery from at least two media chambers into the media outlet of the chamber dosing valve, the media flow can be controlled and continuously maintained.

The chamber dosing valve according to the invention can also be called a proportional dosing valve, because the delivery of the medium, the dosing, is proportional to the distance that the Circumference of the cam disc, which moves the dispensing needle in the feed position. Due to a preferred design of the circumferential contour as an Archimedean spiral, the distance traveled on the circumference of the cam disc during the forward movement is precisely converted into a continuous linear movement of the dispensing needle; the distance traveled on the cam disc is converted in direct proportion to the distance traveled by the dispensing needle during the feed position.

With the metering valve and method according to the invention, a viscous medium can be dispensed in fine doses, and the dispensed quantity is reliably reproducible. The asynchronous oscillating movement of at least two metering needles enables continuous and precise delivery of the medium. By driving the metering needles via a common rotation axis and an external media reservoir, the chamber metering valve can have a small, compact design with few components.

It should also be mentioned that similarly constructed two-chamber systems exist in pump and conveyor technology. In pump and conveyor technology, media is pumped from a storage container and, for example, introduced into a pipe system. Dosing is not possible with such systems. It is important to note that in pump and conveyor technology, in accordance with the requirements placed on it, a suction pressure is built up when the piston is retracted. This suction pressure draws the medium from the container. The medium is then discharged, for example, into a pipe system. This is different with the present invention. Upstream of the metering valve according to the invention, the medium must be pumped from the storage container using a pump or similar conveying system and made available with pressure on the inlet side of the metering valve. By moving the piston back, the pressure applied on the inlet side forces the medium into the media chamber – not sucked in, as in conveyor systems. The invention lies in the ability to expel the medium already in the system from the system. In conveying technology, the medium is introduced into the system, and in dosing technology, the medium is discharged from the system in a controlled manner. In a pumping and conveying system, it is important that the medium is supplied reliably and at a constant pressure in a system, e.g., a pipe system. With a dosing valve, the focus is on metered, locally limited, or precisely dosed dispensing, i.e., the dispensing of a defined quantity. With the help of this dosing valve, lubrication quantities of 0.003 g can be precisely dosed. Therefore, despite some apparent similarities in the system designs, the systems are not comparable with one another, due to, among other things, the installation spaces and dead volumes, and are certainly not interchangeable. In conveying and pumping, the maximization of the material flow is the key. The focus is on precision, whereas in dosing, even the smallest possible dosage units must be dispensed accurately. Consequently, dosing technology strives for the smallest possible installation space, shortest supply line lengths, and minimal dead space volumes. Consequently, a dosing technology specialist would not consult pump and delivery systems to solve a problem that might arise.

This device enables sensitively adjustable small-quantity dosing, even of higher-viscosity lubricants. Media with higher viscosity pose various problems. Dosing is more difficult because high pressures of at least 10 bar must be applied, and even with such media, the media dispensing must be stopped and started quickly. Sealing against material leakage is particularly important. For uninterrupted dosing, the viscous grease flow must be kept flowing continuously. For controlled, sensitively adjustable grease dosing, small sizes and small dead spaces are required, as well as an integrated dosing valve with extremely small chamber volumes.

Controlled dosing of small quantities requires special precautions: The dosing quantity can be adjusted more sensitively the smaller the supply chambers in the pistons are selected and the more directly they are controlled. However, in order to be able to dose larger quantities of media, the drive design must be such that high rotational speeds are utilized on the drive side and induced vibrations are avoided.

The smaller the volume of the supply chambers, the shorter the required stroke lengths. This reduces the size of the camshafts and cam disks, along with the resulting imbalances. This allows for significantly more dynamic response and significantly improved running smoothness.

Due to the small size, disruptive effects such as pressure fluctuations or air pockets, as well as other disruptive factors, can have a greater impact. It is therefore important that the cam design maintains constant feed rates, that a short, consistent piston movement occurs during load changes, and that smooth tangential transitions are achieved in the cam design, as provided for in the particularly preferred version.

Fluctuations in pressure and media output are avoided by ensuring that the movements of the pistons are constant even at high drive-side rotation speeds This is achieved by torque-free piston bearings. At the same time, the piston tappets are pressed against the cam wheels with constant force via a return spring. A high degree of synchronization of both piston movements is achieved by a coupling that acts as directly as possible and is low in wear – torque-free bearings, direct roller contact, and no imbalance in the cam disks.

Preferably, the camshaft is controlled directly using the smallest axes. The direct connection to the engine ensures the smallest rise and fall times and allows for highly dynamic control.

Small dosing chambers allow for more precise control. At the same time, higher speeds are required to enable large volumes and continuous dosing. Stroke movements are shorter in small chambers/installation spaces. This also reduces the cam disks' inertia and their eccentricity (imbalance), which enables low-vibration piston excitation and a high rotation/stroke rate, and requires wear-free piston movement.

The present invention offers numerous advantages, some of which have already been explained above. The metering valve is low-maintenance and very compact. Continuous metering is possible, as one chamber is filled and simultaneously ejected from the other chamber. This allows for the application of grease beads, essentially a continuous application of grease. However, selective dispensing of the lubricant is also possible. This depends entirely on the operation of the system.

Various embodiments of a chamber metering valve and a method according to the invention are described below.

In one embodiment of the chamber metering valve according to the invention, the metering needles are preloaded toward the cam discs by a spring. Thus, the needles are always pressed against a circumferential contour of the cam discs, and the needles are coupled to the cam disc. For this purpose, a compression spring can be used, for example, which is supported on one side by a coupling end of the metering needle facing the cam disc and on the other side by the media chamber or a housing of the chamber metering valve. The spring ensures continuous drive transmission between the cam disc and the metering needle.

Alternatively or additionally, the dispensing needles can also be pushed through the medium against the cam disc, which flows under pressure into the media chamber as soon as the dosing needle begins to move backwards.

Furthermore, the dispensing needle can have a roller at its coupling end that rolls against the circumferential contour of the cam disc. As the cam disc rotates, the roller rolls smoothly along the circumferential contour and transfers the drive movement of the cam disc to the dispensing needle, either for extruding the medium from the media chamber during the dispensing position or for releasing the chamber volume to fill the media chamber during the loading position.

Furthermore, the dispensing needles are preferably mounted in the media chambers without torque. For this purpose, a seal package and/or bearings can be provided, for example.

In one embodiment of the chamber metering valve according to the invention, the drive unit is designed as an electric motor. The electric motor can be coupled to the rotational axis via its output shaft directly or indirectly, e.g., via a belt. Electric motors are compact and can generate high speeds. The motor is advantageously designed as a modular unit and can be mounted directly on the metering unit.

In a further embodiment of the chamber metering valve according to the invention, a check valve can be provided at the media inlet to the media chamber, preventing backflow from the media chamber into the supplying conveying system. Therefore, any medium that has been filled into the media chamber is discharged exclusively via the chamber's media outlet.

Furthermore, a control valve, preferably a check valve, is advantageously provided in each media outlet of each individual chamber, which prevents a backflow into the respective media chamber during an advancing movement of the dosing needle of an adjacent chamber or during a backward movement of the dosing needle of this chamber.

According to a particularly preferred embodiment of the invention, the media volumes from all media chambers are fed into a common media outlet. For this purpose, the medium is ejected into a common channel by each piston, also called a tappet, in this case usually referred to as a dosing needle. This means that the lubricating grease or other medium in the system is drawn into the piston chamber, in this case usually referred to as the media chamber, by one piston, while the other piston is in ejection mode and ejects the medium again. The ejection by both pistons takes place into one and the same outlet channel and flows into the common media outlet. In a particularly preferred embodiment of the invention, the cam disk is designed so that the ejection interval of both pistons overlaps. With a correspondingly precise design of the cam disks, also known as cams, the overall ejection is completely uninterrupted, i.e. not just with low pulsation, but pulsation-free. It has been shown that with exact alternating operation, i.e. when one piston is in the loading interval while the other is in the ejection interval, although low-pulsation dosing is possible, a lubricating grease bead of exactly the same thickness or width cannot be ejected. Instead, slight deviations in the amount of lubricating grease have been observed, i.e. the bead becomes somewhat uneven. By creating an overlap interval, this problem is eliminated; shortly before the piston currently in the ejection interval ends its ejection activity, the second piston already begins its ejection interval.

The check valves and control valves mentioned above prevent carryover or run-on in the outlet, which can be a problem, especially with viscous media introduced at high working pressures. The shut-off valve at the media outlet is particularly important, as it promotes run-on and drip-free media dosing.

1. 1. Der Hinweg, d. h. der Weg, auf welchem der Ausstoß, also die Vorwärtsbewegung der Dosiernadel stattfindet, ist länger als der Rückweg, also der Weg, auf welchem die Medienkammer geladen wird. Die unterschiedliche Weglänge wird durch unterschiedliche Radien erzielt. Auf dem Hinweg wird bevorzugt eine archimedische Spirale genutzt. Eine Spirale wird pro Grad in exakt denselben linearen Weg umgesetzt. Hierdurch bewegt sich folglich der Stößel immer um den gleichen Weg nach vorne. Auf diese Art und Weise wird ein gleichmäßiger Ausstoß überhaupt möglich.
2. 2. Auf dem Rückweg hingegen ist die exakte Form unerheblich, denn über eine Feder erfolgt die Rückstellung des Kolbens und es ist lediglich wichtig, dass zum neuen Ausstoßzeitpunkt die Kammer vollständig gefüllt ist. Infolgedessen wird für den Rückweg bevorzugt ein einfacher Radius verwendet.
3. 3. Der Überlappungsbereich, in dem beide Kolben dosieren, ist bevorzugt ein einfacher Radius. Die Spirale des Vorlaufs endet mit Beginn des Überlappungsbereichs. Ein Fachmann ist in der Lage, den Radius des Überlappungsbereichs experimentell zu ermitteln, z. B. indem so lange der Radius angepasst und geändert wird, bis die gewünschte unterbrechungsfreie Dosierung stattfindet.
4. 4. Es wird in einem Abschnitt von mehr als 180 Grad des Kurvenscheibenumfangs dosiert, also ausgestoßen. Entsprechend ist der Rückweg kleiner als 180 Grad.

Some preferred designs and properties of the cam discs are explained below:

1. 1. The forward path, i.e. the path along which the dispensing needle is discharged, i.e., the forward movement, is longer than the return path, i.e., the path along which the media chamber is loaded. The different path lengths are achieved by different radii. An Archimedean spiral is preferably used on the forward path. A spiral is converted into exactly the same linear path per degree. As a result, the plunger always moves forward the same distance. This makes consistent discharge possible.
2. 2. On the return path, however, the exact shape is irrelevant, as the piston is reset by a spring, and it only matters that the chamber is completely filled at the new ejection point. Consequently, a simple radius is preferred for the return path.
3. 3. The overlap area in which both pistons meter is preferably a simple radius. The spiral of the pre-run ends at the beginning of the overlap area. A person skilled in the art is able to determine the radius of the overlap area experimentally, e.g., by adjusting and changing the radius until the desired uninterrupted dosing takes place.
4. 4. Metering, or ejection, takes place over a section of the cam disk circumference of more than 180 degrees. Accordingly, the return path is less than 180 degrees.

This multi-chamber metering valve has various advantages, some of which have already been mentioned above. The cam disk design described above results in even more advantages, namely: No referencing is necessary. It is completely irrelevant what state the system is in when it is stopped; it can simply continue. It also makes no difference whether an identical amount of lubricant is to be dispensed in each cycle or whether, for example, a program is to be run in which, for example, two individual drops are to be dispensed alternately and then a short distance is to be metered continuously. None of this is important for this system, as it is completely reference-free. It is an endless system. The system can be restarted at any point. Even if the emergency stop is activated, the system can simply be restarted again.

Advantageously, the common media outlet may have a check valve or a control valve, preferably a check valve, for regulating the discharge of the medium from the chamber dosing valve and in particular for preventing backflow into lines and channels of the dosing valve leading to the common media outlet.

The check valves in the media inlets, the control valves or check valves in the media outlets and in the media outlet can together form a valve system for regulating the continuous media flow and thus the applied media quantity.

The chamber metering valve according to the invention, unlike, for example, the extruder-type dispenser known in the prior art, is particularly well suited for ointment-like and viscous, so-called pasty media, such as lubricants. With this metering device, lubricating greases with a consistency that falls into classes 000 to 3 according to the NLGI (National Lubrication Grease Institution) classification system can be metered (see also DIN 21 818). Gear greases, for example, fall into the NLGI consistency classes 000, 00, 0, and 1, whereas rolling bearing greases and plain bearing greases fall into classes 2 and 3 (as well as 4).

Since modern machine, automation and process technologies often require only small and finely dosed process media, the media chambers advantageously have a maximum volume of 5,000 mm ³ , in particular of 1,000 mm ³ , preferably of 500 mm ³ , even more preferably of 200 mm ³ or less.

Furthermore, the media chambers are advantageously designed as elongated cylinders in order to achieve an advantageous stroke length of the dosing needles.

To ensure a continuous flow of medium from the media chambers, the control valve or check valve in the media outlets is designed such that a minimum pressure in the media chamber of 30 bar, preferably 35 bar, and particularly preferably over 40 bar, is required to open the control valve or check valve. These pressures ensure that sufficient thrust is present to continuously press medium into the media outlet and to release a defined amount of medium from the chamber metering valve.

In yet another embodiment of the chamber dosing valve according to the invention, the dosing unit has a guide sleeve for each dosing needle to guide the oscillating movement of the dosing needle. Advantageously, at least two, preferably at least three, independent sealing devices are provided in the guide sleeve to seal between the media chamber and the dosing needle. The sealing devices can be formed, for example, by sealing rings that are held by the guide sleeve and form a contact surface for the dosing needle. The at least two sealing devices form a sealing package that reliably prevents uncontrolled leakage of medium from the media chamber.

In a preferred embodiment, three O-ring seals are provided in each media chamber. Their combination in series ensures the required high level of tightness of the system under the demanding process requirements described here, especially the high working pressures. Particularly preferably, the complete seal package is mounted in a sleeve and simultaneously serves to guide the dispensing needle.

In yet another embodiment of the chamber metering valve according to the invention, the medium in the media chambers can be tempered by means of a heating and/or cooling device. The temperature of the medium in the chambers can thus be adjusted to the requirements for a defined and reproducible discharge of the medium from the chamber metering valve.

According to a further aspect of the present invention, a dosing system is further provided, which comprises a chamber dosing valve as described above and a control unit for the chamber metering valve. Using the control unit, for example, a rotational speed of the rotational axis can be set; the check valves, metering valves, and/or control valves can be controlled, e.g., depending on an applied pressure; a temperature for the media chambers can be determined, and/or the medium pressure at the media inlet can be adjusted. In particular, the chamber metering valve can be controlled depending on the viscosity of a medium, so that a reproducible dispensing of a preset amount of media can be variably determined within a defined time window.

Short character description

Figur 1:

eine perspektivische Darstellung eines Kammerdosierventils der vorliegenden Erfindung;

Figur 2:

das Kammerdosierventil aus Figur 1 in einer ersten Seitenansicht;

Figur 3:

eine weitere Seitenansicht des Kammerdosierventils der Figur 1;

Figur 4:

eine Vorderansicht des Kammerdosierventils der Figur 1;

Figur 5:

eine erste Schnittdarstellung des Kammerdosierventils der Figur 1 in Längsrichtung einer Rotationsachse des Kammerdosierventils (Schnitt A - A in Figur 3);

Figur 6:

eine zweite Schnittdarstellung des Kammerdosierventils der Figur 1 in Querrichtung der Rotationsachse des Kammerdosierventils (Schnitt B - B in Figur 4);

Figur 7:

eine dritte Schnittdarstellung durch die Antriebseinheit des Kammerdosierventils der Figur 1 (Schnitt C - C in Figur 3);

Figur 8:

eine drei-dimensionale Detailansicht einer Dosiereinheit und einer Antriebseinheit des Kammerdosierventils aus Figur 1;

Figur 9:

eine Explosionsdarstellung diverser Bauteile des Kammerdosierventils aus Figur 1; und

Figur 10:

eine Detaildarstellung eines bevorzugten Ausführungsbeispiels einer Kurvenscheibe zum Einsatz in einem Kammerdosierventil der Figur 1, gleichzeitig eine schematische Darstellung eines Verfahrens nach der vorliegenden Erfindung anhand von Rotationsphasen der Kurvenscheibe auf der Rotationsachse des Kammerdosierventils aus Figur 1

The present invention is easier to understand with reference to the accompanying figures, which illustrate an advantageous embodiment of the chamber metering valve by way of example, without limiting the present invention to them. The figures show:

Figure 1:

a perspective view of a chamber metering valve of the present invention;

Figure 2:

the chamber dosing valve Figure 1 in a first side view;

Figure 3:

another side view of the chamber dosing valve of the Figure 1 ;

Figure 4:

a front view of the chamber dosing valve of the Figure 1 ;

Figure 5:

a first sectional view of the chamber dosing valve of the Figure 1 in the longitudinal direction of a rotation axis of the chamber dosing valve (section A - A in Figure 3 );

Figure 6:

a second sectional view of the chamber dosing valve of the Figure 1 in the transverse direction of the rotation axis of the chamber dosing valve (section B - B in Figure 4 );

Figure 7:

a third sectional view through the drive unit of the chamber dosing valve of the Figure 1 (Section C - C in Figure 3 );

Figure 8:

a three-dimensional detailed view of a dosing unit and a drive unit of the chamber dosing valve from Figure 1 ;

Figure 9:

an exploded view of various components of the chamber dosing valve from Figure 1 ; and

Figure 10:

a detailed view of a preferred embodiment of a cam disc for use in a chamber metering valve of the Figure 1 , at the same time a schematic representation of a method according to the present invention based on rotation phases of the cam disc on the rotation axis of the chamber dosing valve from Figure 1

Character description

Certain terms are used in the following description for convenience and are not intended to be limiting. For example, the words "right," "left," "bottom," and "top" indicate directions in the drawing to which reference is made. The terms "inside," "outside," "below," "above," "left," "right," or similar terms are used to describe the relative arrangement of designated parts, the relative movement of designated parts, and the directions toward or away from the geometric center of the invention, as well as designated parts thereof, as illustrated in the figures. These spatial relative terms also include positions and orientations other than those illustrated in the figures. For example, if a part illustrated in the figures is reversed, elements or features described as "below" are then "above." The terminology includes the words expressly mentioned above, derivatives of the same, and words of similar meaning.

To avoid repetition in the figures and the associated description of the various aspects of the invention, certain features should be understood as common to different aspects and embodiments. The omission of an aspect from the description or a figure does not imply that this aspect is missing in the associated embodiment. Rather, such omission can serve to improve clarity and avoid repetition. In this context, the following definition applies to the entire further description: If reference symbols are included in a figure for the purpose of graphic clarity but are not mentioned in the immediately associated descriptive text, reference is made to their explanation in preceding figure descriptions. If, in addition, the descriptive text immediately associated with a figure mentions reference symbols that are not included in the associated figure, reference is made to the preceding and following figures. Similar reference symbols in two or more figures represent similar or identical elements.

The invention is described below using the single exemplary embodiment across the figures.

In the Figures 1 to 9 An embodiment of a chamber metering valve and a method for the continuous and low-pulsation metering of a viscous medium using such a chamber metering valve according to the invention are presented. The embodiment shown is particularly well suited for the metering and application of Lubricants such as greases, as used in machine, automation, and process technology. In principle, a chamber metering valve according to the invention can also be used to meter oils, as well as for almost solid, highly viscous, and sticky media. Figure 10 a particularly preferred design of a cam disc is shown, as it can preferably be used in a chamber dosing valve 100.

Figure 5 shows a longitudinal section through the chamber metering valve 100 with two media chambers 5, 6 according to the present invention. The chamber metering valve comprises a drive unit 1 and a metering unit 2. Details of the chamber metering valve 100 are described with reference to Figure 9 described.

The dosing unit 2 has a media inlet 3 for supplying the chamber dosing valve 100 with a medium to be applied from a reservoir (not shown) and a media outlet 4 for continuously dispensing the medium from the chamber dosing valve 100. Connections for an alternative media inlet 3' and an alternative media outlet 4' are provided in order to be able to accommodate the structural conditions at the site of use if necessary. The dosing unit 2 has a first media chamber 5 and a second media chamber 6, which are aligned parallel to one another in a housing of the dosing unit 2. The media chambers 5 and 6 each have a media inlet 7 and 7', respectively, and a media outlet 8 and 8', respectively. The media outlets 8 and 8' of the at least two media chambers 5 and 6 each open into the media outlet 5 of the dosing unit 2. Furthermore, each media chamber has a dosing needle that is displaceably mounted in the chamber, i.e. a first dosing needle 9 in the first media chamber 5 and a second dosing needle 10 in the second media chamber 6. The dosing needles 9 and 10 each have a feed end 11, 11' and a coupling end 12, 12'. Coupling sleeves 13, 13' are firmly attached to the coupling end 12, 12' of the dosing needles 9 and 10, which serve as bearings for rollers 14, 14' at the end of the dosing needles 9 and 10. Furthermore, a spiral spring 15, 15' is provided for each dosing needle 9 and 10, which is clamped between the coupling end 12, 12' of the dosing needles and a housing-fixed stop 16, 16'. The spiral springs 15, 15' clamp the dosing needles 9 and 10 in the loading position, ie in Figure 1 to the left, forward.

A check valve is provided in each of the media inlets 7 and 7' leading to the media chambers 5 and 6, respectively. In the section of the Figure 2 The check valve 17 is located in the media inlet 7', which prevents the medium from flowing back from the media chamber toward the reservoir. A similar check valve is also provided in the media inlet 7.

Furthermore, a control valve or check valve 18 is provided in each media outlet 8 or 8', which prevents backflow into the respective media chamber and regulates the outlet of the medium from the respective media chamber.

In addition, a control or check valve 19 is provided in the common media outlet 4, into which the media outlets 8 and 8' open (see Figure 5 ), which supports the fine dosing of the media application.

The check valves and control valves prevent carryover or overflow at the media outlet and the media outlets, which can be particularly problematic with viscous media that are fed at high working pressures. The valve at the media outlet, in particular, prevents overflow and drip-free media dosing.

The coupling ends 12 of the dispensing needles 9 and 10 are aligned in the direction of a rotational axis 20 and perpendicular to it. The rotational axis 20 is rotatably mounted in bearings 21 and 21' in the housing of the dispensing unit 2. Arranged on the rotational axis 20 are a first cam disc 22, which interacts with the first dispensing needle 9, and a second cam disc 23, which interacts with the second dispensing needle 10, which rotate together with the rotational axis 20. The cam discs 22 and 23 are mounted eccentrically, rotated by 180° relative to one another, and offset longitudinally on the rotational axis 20. The rotational axis 20 and the cam discs 22 and 23 together form a type of camshaft, which acts on the dispensing needles 9 and 10 of the media chambers 5 and 6. For this purpose, the dispensing needles 9 and 10, with their respective rollers 14, rest against a circumferential contour 24 and 24', respectively, of the cam discs 22 and 23, with the rollers 14 being pressed against the circumferential contours 24 and 24', respectively, by the compression springs 15. The dispensing needles 9 and 10 are thus coupled to the cam discs 22 and 23 via the rollers 14. The rotation axis 20, in turn, is coupled to the drive unit 1 so that it can be driven in rotation by the latter.

As can be seen from the Figures 5 and 6 As can be seen, the dosing unit 2 has a guide sleeve 30, 30' for each of the dosing needles 9 and 10 to guide a movement of the dosing needles 9 and 10, which are respectively connected to the media chambers 5 and 6. The guide sleeves 30, 30' serve to support the dosing needles in a torque-free manner.

At the same time, the guide sleeves 30, 30' function as a sealing package. In the preferred embodiment shown, each guide sleeve 30, 30' contains three seals 31, 33, 34 or 31, 33' and 35', which form a gap between the dispensing needle and Seal the media chamber. The seals 31, 31', 33, 33', 35, 35', for example sealing rings such as O-rings, are arranged separately from one another in the guide sleeve 30 and 30', respectively, and thus each form an independent seal. These seals together form a seal package for sealing the media chamber and the dispensing needle. The combination of the seals 31, 33, 35 and 31', 33', 35' arranged in series ensures the required high level of tightness for demanding process requirements.

For venting each media chamber 5 and 6, a vent 32, 32', e.g. a vent valve, is provided.

For the metered dispensing of a viscous medium, the dispensing needles 9 and 10 of the dispensing unit 2 are movably driven by the drive unit 1 by a rotation of the rotation axis 20, oscillating between a forward movement as a dispensing position and a backward movement as a loading position. The rotation axis 20 is in turn driven by the drive unit 1. The two cam discs 22 and 23 are shaped and arranged offset from one another on the rotation axis 20 in such a way that essentially a forward movement of the first dispensing needle 9 occurs during a backward movement of a second dispensing needle 10, so that a continuous dispensing of the medium from the chamber dispensing valve takes place. In the loading position, i.e. during a backward movement of the dispensing needles 9 and 10, medium is supplied to the media chambers 5 and 6 under pressure from a reservoir. In the dispensing position, i.e. When the dispensing needles 9 and 10 advance, medium is extruded from the respective media chamber. Due to the counter-rotation of the dispensing needles 9 and 10, medium is discharged alternately from either the first media chamber 5 or the second media chamber 6. The synchronization of the cyclic and asynchronous advance movements for the discharge of medium from the chambers can be achieved via the shape and dimensioning of the cam discs 22 and 23 and via the rotation speed of the rotation axis 20.

Figure 8 shows a three-dimensional partial section of the chamber dosing valve with the rotation axis 20, which carries the first cam disc 22 and the second cam disc 23, and the dosing needles 9 and 10 as well as their coupling by means of the rollers 14 to the cam discs 22 and 23.

In Figure 9 Among other things, the components of the drive unit 1 are shown (see also Figure 7 ). In the illustrated embodiment of the chamber metering valve 100, the drive unit is designed as an electric motor 50. The electric motor 50 comprises an output shaft 51, which protrudes outwardly from a housing of the electric motor 50. A support plate 54 is attached to the housing, on which a first drum 52 and a second drum 53 are rotatably mounted offset from the first drum 52. The first drum 52 can be coupled to the output shaft 51 and the second drum 53 can be coupled to the rotation axis 20 of the dosing unit 2. A transmission belt 55 is placed around the first drum 52 and the second drum 53 so that rotation of the output shaft 51 can be transmitted via the first drum 52 and the belt 55 to the second drum 53 and thus to the rotation axis 20. A cover 56 can be attached over the drums 52 and 53 as well as the belt 55. With the electric motor 50, speeds of up to 1,200 min ^-1 are achieved on the rotation axis 20. For continuous delivery of the medium from the chamber dosing valve, speeds of 50 to 100 min ^-1 are usually used.

To control the dosing and application of the medium from the chamber dosing valve, a control unit can be provided on the chamber dosing valve or remotely therefrom, which, for example, controls the drive unit and the valves of the chamber dosing valve. Furthermore, a device for heating and/or cooling the medium in the media chambers can be provided, which can also be controlled via the control unit. The media chambers are preferably machined from an aluminum block. Any accompanying heating or cooling is quickly transferred to the medium through the aluminum.

In Figure 10 An advantageous embodiment of the cam disk 22 is described. The cam disks 22, 23 are identically constructed. However, they are arranged offset along the longitudinal axis of the rotation axis 20 according to the distance between the media chambers 5 and 6. For the present embodiment of a chamber metering valve with two media chambers, the cam disks 22 and 23 are also provided rotated by 180° on the rotation axis 20.

In Figure 10 Only one cam disc 22 is shown. It is eccentrically designed, as can be clearly seen. The circumferential contour 24 has various sections, which divide the rotation of the cam disc around the rotation axis 20 into different rotation phases. The individual rotation phases can be distinguished from one another based on their geometric design. The main sections can be a forward sector 40 for the forward movement and a return sector 41 for the backward movement of the dispensing needle. The forward sector 40 extends from the low point 45, which can also be regarded as the starting point of a movement cycle of a dispensing needle, to the high point 44. The return sector 41 extends from the high point 44 to the low point 45.

As can be seen in the preferred embodiment shown, a circumferential contour section of the advance sector 40 differs from a circumferential contour section of the return sector 41 in such a way that the advance movement lasts longer than the return movement - the path of the advance sector 40 is longer than the path of the return sector 41.

Due to the above path difference, an overlap sector 42 results, in which both dispensing needles 9 and 10 execute a feed movement simultaneously for a short period of time. The two dispensing needles 9 and 10 move briefly in the same direction. During this period, one cam disc has already begun the feed movement by crossing the low point 45, while the other cam disc is at the end of the feed movement, in the overlap sector 42. This prevents a dead center during the media dispensing during the reversal of the movement.

The circumferential contour 24 can be divided into different sections, which can be distinguished based on their geometric properties.

As already mentioned above, the advance sector 40 extends from the low point 45 to the high point 44. In the first section of this path, the circumferential contour 24 is a straight line - reference numeral 43. This is followed by a large section in the shape of an Archimedean spiral - reference numeral 46. In this section, the path length of the cam disc is directly proportional to the path of the dispensing needle. Towards the high point 44, there is a transition radius from the advance 40 to the return 41 - the overlap sector 42.

The return sector 41 extends from the high point 44 to the low point 45. For the most part, this is a simple radius. Immediately before the low point 45, another radius is provided—the transition radius from the return to the forward point 47.

As already mentioned, for a continuous feed movement of the dispensing needle, the circumferential contour in the main part of the advance sector 40 is advantageously designed in a spiral shape (section 46). This means that the radius continuously increases from the beginning of the advance phase to the end of the advance phase. At the same time, a radius of the circumferential contour in the return sector 41 can be oval. This means that the radius increases from the beginning of the return phase to the middle of this phase and then decreases again until the end of the return phase. This results in a symmetrical change in the radius around the middle of the return phase.

Figure 10 illustrates the special shape of the cam disks 22 and 23 mounted on the rotation axis 20 in a preferred embodiment of a chamber metering valve 100 according to the invention. In the forward sector 40, the circumferential contour 24, 24' of the cam disks is largely spiral-shaped, and in the return sector 41, a continuously increasing radius is provided such that the circumferential contour 24, 24' forms a kind of semi-oval. This shape results in a largely counter-rotating movement of the metering needles 9 and 10, whereby the emptying and refilling of each media chamber 5 and 6 takes place alternately in a single revolution of the rotation axis 20. In addition, the circumferential contour 24, 24' in the transition sectors 42 and 47 is shaped in such a way that an overlapping area of the movement of both dispensing needles results, in which a targeted, short-term, co-directional advance movement of the dispensing needles in the media chambers occurs. At the beginning of a cycle at the starting point 43, the advance phase starts via the advance sector 40, which leads to the forward movement of the dispensing needle in the media chamber and thus to its emptying. This is followed by the aforementioned overlap sector 42 at the end of the advance sector 40. Subsequently, upon reaching a high point 44, a return phase starts via the return sector 41, during which a backward movement of the dispensing needle in the media chamber occurs and this is refilled with medium from the reservoir. The cycle ends when the low point 45 is reached. The tangentially executed transition area 47 leads back via the low point 45 as the starting point of the movement to the straight line 43 as the initial path of the cycle.

List of reference symbols

1

drive unit

2

Dosing unit

3, 3'

Media entrance

4, 4'

Media output

5

first media chamber

6

second media chamber

7, 7'

Media entrance

8, 8'

Media outlet

9

first dispensing needle

10

second dosing needle

11, 11'

Feed end

12, 12'

Coupling end

13, 13'

coupling sleeve

14, 14'

role

15, 15'

spiral spring

16, 16'

stop

17

check valve

18

control valve

19

control valve

20

axis of rotation

21, 21'

warehouse

22

first cam disc

23

second cam disc

24, 24'

circumferential contour

30, 30'

Guide sleeve

31, 31'

seal

32, 32'

Ventilation

33, 33'

seal

34, 34'

seal

40

Lead sector

41

Return sector

42

Overlap sector

43

Straight

44

high point

45

Low point

46

spiral

47

Transition radius from return to supply

50

electric motor

51

Output shaft

52

first drum

53

second drum

54

carrier plate

55

transmission belt

56

cover

57

Electrical connection

100

Chamber dosing valve

Claims (15)

1. Chamber dosing valve (100) for the metered dispensing of a viscous medium, comprising a metering unit (2) and a drive unit (1) which are connected to each other, wherein the metering unit (2) comprises at least one media inlet (3), at which the medium is supplied under pressure to the metering unit, and a media outlet (4), via which the medium is dispensed from the chamber dosing valve,

   wherein the metering unit comprises a media chamber (5) having a media entrance (7) and a media exit (8),

   wherein the media chamber (5) comprises a metering needle (9) which is movable in an oscillating manner between a forward movement as a metering position and a backward movement as a charging position,

   wherein, during the backward movement of the metering needle (9), the medium is pressed into the media chamber (5) as a result of the applied pressure at the media inlet (3),

   wherein the metering unit comprises at least two media chambers (5, 6) having a media entrance (7, 7') and a media exit (8, 8'),

   wherein the media exits (8, 8') of the at least two media chambers (5, 6) open into the media outlet (4) of the metering unit,

   characterized in that

   each media chamber (5, 6) comprises a metering needle (9, 10) which in each case is coupled to a cam disk (22, 23), and the cam disks (22, 23) are arranged on a common rotating axle (20) which is coupled to the drive unit (1) such that, as the rotating axle (20) rotates, the metering needles (9, 10) are in each case movable in an oscillating manner between the forward movement as the metering position and the backward movement as the charging position,

   wherein the at least two cam disks (22, 23) are shaped and arranged offset from each other on the rotating axle (20) in such a way that substantially a forward movement of a first metering needle (9) takes place during a backward movement of a second metering needle (10), so that the medium is continuously dispensed from the chamber dosing valve.
2. Chamber dosing valve (100) according to claim 1,
   characterized in that
   the metering needles (9, 10) are biased in the direction of the cam disks (22, 23) by means of a spring (15).
3. Chamber dosing valve (100) according to claim 1 or 2,
   characterized in that
   the metering needles (9, 10) have, at a coupling end (12), a roller (14) which bears in a rolling manner against a circumferential contour (24, 24') of a cam disk (22, 23).
4. Chamber dosing valve (100) according to any one of the preceding claims,
   characterized in that
   the drive unit is designed as an electric motor, which directly or indirectly drives the rotating axle.
5. Chamber dosing valve (100) according to any one of the preceding claims,
   characterized in that
   a check valve (17) is provided at the media entrance (7, 7') to the media chamber (5, 6), which prevents any backflow from the media chamber (5, 6).
6. Chamber dosing valve (100) according to any one of the preceding claims,
   characterized in that
   the media exits (8, 8') from the media chambers (5, 6) open into a common media outlet (4) from the metering unit (2), and a control valve or a check valve (18) is provided in each media exit (8, 8'), which prevents any backflow into the respective media chamber (5, 6).
7. Chamber dosing valve (100) according to any one of the preceding claims,
   characterized in that
   a check valve (19) or a control valve is arranged in the region of the common media outlet (4).
8. Chamber dosing valve (100) according to claim 6 or 7,
   characterized in that
   the control valve or check valve (18) is designed such that a minimum pressure in the media chamber of 30 bar, preferably 35 bar, particularly preferably 40 bar, is required in order to open the control valve or check valve (18).
9. Chamber dosing valve (100) according to any one of the preceding claims,
   characterized in that
   the metering unit (2) has, for each metering needle (9, 10), a guide sleeve (30) for guiding the oscillating movement of the metering needle (9, 10), in which in each case at least two mutually independent sealing devices are provided for sealing between the media chamber (5, 6) and the metering needle (9, 10).
10. Chamber dosing valve (100) according to any one of the preceding claims,
    characterized in that
    each media chamber (5, 6) has a maximum volume of 5000 mm³, in particular 1000 mm³, preferably 500 mm³, even more preferably 200 mm³ or less.
11. Chamber dosing valve (100) according to any one of the preceding claims,
    characterized in that
    the medium in the media chambers (5, 6) can be temperature-controlled by means of a heating or cooling element.
12. Chamber dosing valve (100) according to any one of the preceding claims,
    characterized in that
    a circumferential contour (24, 24') of the cam disks (22, 23) has a forward run sector for the forward movement and a return run sector for the backward movement of the reciprocating piston, wherein a contour portion of the forward run sector differs from a contour portion of the return run sector in such a way that the forward movement lasts longer than the backward movement.
13. Metering system, comprising a chamber dosing valve (100) according to claim 1 and a control unit for the chamber dosing valve.
14. Metering system according to the preceding claim,
    characterized in that
    the control unit controls a speed of rotation of the rotating axle (20) and/or check valves (17), metering valves (19) and/or control valves (18) as a function of an applied pressure, in particular as a function of the viscosity of a medium.
15. Method for metering a viscous medium, continuously and with little pulsation, using a chamber dosing valve (100),

    wherein the medium is supplied under pressure to the chamber dosing valve by way of a conveyor unit,

    wherein a media chamber (5) in the chamber dosing valve has a metering needle (9) which is moved between a forward movement as a metering position and a backward movement as a charging position,

    wherein during the backward movement of the metering needle (9) the conveyor unit presses the medium into the media chamber (5), and during the forward movement the metering needle (9) presses the medium out of the media chamber (5) into a media outlet (4), via which the medium leaves the chamber dosing valve,

    characterized in that

    at least two media chambers (5, 6) are provided, the metering needles (9, 10) of which are in each case moved between the metering position and the charging position by means of a cam disk (22, 23) arranged on a common rotating axle (20),

    wherein the cam disks (22, 23) are shaped and arranged offset from each other on the rotating axle (20) in such a way that the metering position of a first metering needle (9) substantially alternates with the charging position of a second metering needle (10), so that medium from one of the media chambers (5, 6) is being pressed into the media outlet (4) at all times during the metering process,

    as a result of which the medium is metered out of the chamber dosing valve continuously and with little pulsation.

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