EP4067651A1 - Chamber dosing valve, metering system for same and method for dispensing a viscous medium - Google Patents

Abstract

The present invention relates to a chamber metering valve (100) for the metered delivery of a viscous medium, having a metering unit (2) and a drive unit (1), which are connected to one another. The dosing unit (2) comprises at least one media inlet (3) at which the medium is fed to the dosing unit under pressure, and a media outlet (4) via which the medium is discharged from the chamber dosing valve, the dosing unit having a media chamber (5) with a media inlet (7) and a media outlet (8). The media chamber (5) also includes a dosing needle (9) which can be moved in an oscillating manner between a forward movement as a dosing position and a backward movement as a loading position, with the backward movement of the dosing needle (9) causing the medium to flow out due to the pressure applied at the medium inlet (3 ) is pushed into the media chamber (5). According to the invention, the dosing unit comprises at least two media chambers (5, 6) with a media inlet (7, 7') and a media outlet (8, 8'), the media outlets (8, 8') of the at least two media chambers (5, 6) being in the media outlet (4) of the dosing unit, each media chamber (5, 6) comprising a dosing needle (9, 10) which is coupled to a cam disc (22, 23), and the cam discs (22, 23) on a common one axis of rotation (20), which is coupled to the drive unit (1), so that when the axis of rotation (20) rotates, the dosing needles (9, 10) can each be moved in an oscillating manner between the forward movement as the dosing position and the backward movement as the loading position. The at least two cam disks (22, 23) are shaped in such a way and are arranged offset to one another on the axis of rotation (20) in such a way that a first metering needle (9) is essentially advanced during a backwards movement of a second metering needle (10), so that continuous dispensing of the medium from the chamber metering valve. The invention further relates to a dosing system and a dosing method.

Description

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

technical field

In machine, automation and process technology, the application and dosing of various process media that is as precise as possible, locally delimitable and as comprehensive as possible is required. The latter are characterized by very different physical and chemical properties.

The process media to be dosed include e.g. B. oils, paints, lubricants such. B. fats, resins, silicones, adhesives, sealants, gels, pastes, liquid polymers, casting compounds and pasty substances of pharmaceutical, food technology or general industrial processing technology.

The media to be dosed and the user scenarios are characterized by a large variety of parameters, which result, for example, from the variety of applications, the characteristic material properties of the media to be applied, their provision, the media and environmental conditions prevailing during storage and application (e.g. temperature and humidity), used and necessary process pressures, the chemical reaction behavior and the possible corrosive effects of the media and, above all, their viscosity. A further complication is the requirement to provide the media in a controlled and finely dosed manner in a wide range of quantities or volumes, with repeat accuracy and as far as possible without interruption.

State of the art

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

So dosing systems for dosing small amounts of liquids and media of low viscosity are known, which are designed like a syringe as a one-chamber system in different sizes, flow rates and forms of realization. The mostly liquid dosing substances are applied with pinpoint accuracy, for example via hollow needles, via a longitudinal movement of a piston. Such dosing systems are known and used by a. in process engineering apparatus technology, for the controlled filling of mostly liquid media and mixtures in special containers. Your field of application is determined, for example, by the requirements of the filling technology, the procedural media provision or use in the laboratory environment.

The field of application is expanded with the use of comparable single-chamber systems in assembly technology, in order to also apply small amounts of process media of all kinds, some of which have a higher viscosity. As current representative examples, syringes and dosing small quantities in electrical and electronic casting, the application of oily lubricants and the application of reaction agents and process media in adhesive and sealing technology should be mentioned at this point.

Such single-chamber dosing systems include, for example, a dosing unit and a drive unit, which are connected to one another in order to apply a medium from the dosing unit. The dosing unit comprises at least one media inlet, at 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, via which the medium enters the chamber and is administered from it again. The media chamber includes a dosing piston which is moveable by the drive unit between a reverse movement while the medium enters the chamber and a forward movement for dispensing the medium through the medium outlet.

Such dosing systems based on one-chamber systems are characterized above all by the simplicity of their structure and the resulting robustness in the field of application. The dimensional design of the chambers and the easily controllable linear movement of the pistons result in a very simple and repeatable, but only limited possibility of media delivery. The system-immanent disadvantage of the restriction in these forms of implementation refers both to the total amount and also the process-continuous provision of the medium. The use of such dosing systems does not allow the conveyance of highly viscous media and requires pauses to refill the process chambers.

As mentioned above, in the known chamber metering systems, a plunger in the manner of a syringe is pulled, whereby the lubricant is sucked into the chamber and by depressing the plunger the lubricant is expelled. This has the advantage that dosing can be carried out independently of the pressure. However, as mentioned briefly above, the disadvantage is that the lubricant has to be recharged even with larger chamber volumes, which means an interruption of approx. 30 seconds. means in the process flow. must z. If, for example, a part is wetted with lubricant in a production process, the production process must be interrupted for the corresponding loading time in order to load the chamber metering valve. It has to be e.g. B. be suspended every 10 cycles a cycle to load the lubricant back into the chamber. Another disadvantage of the chamber metering valve is that continuous grease dispensing is not possible due to the loading process. Longer stretches of lubricant, for example the application of lubricant beads, are therefore impossible.

Another system is known in the prior art, namely a dispenser that works in the manner of an extruder. This system is not suitable for less viscous media, as it would otherwise work very imprecisely. In addition, the system is very pressure-sensitive and can be used up to a maximum of 15 bar. In addition, the stator is susceptible to wear. However, unlike the known chamber metering valves, the dispenser allows a continuous and uniform delivery of lubricating grease (subject to the restrictions described above).

task

It is an object of the present invention to improve known chamber metering valves in such a way that low-pulsation, preferably uninterrupted application of media of different viscosity is possible with continuous media delivery. One goal is that interruptions in the dosing process due to loading of the chamber dosing valve should be eliminated as completely as possible. The task is also to provide a method for metered dispensing of a viscous medium, it being possible for the dispensing to take place continuously and with little pulsation.

invention description

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

A chamber metering valve for the metered delivery of a viscous medium according to the present invention comprises a metering unit and a drive unit which are connected to one another. The dosing unit has at least one media inlet, at which the medium is supplied to the dosing unit under pressure. The dosing unit also has a media outlet, via which the medium is released from the chamber dosing valve. Furthermore, the dosing unit has a first media chamber, which includes a media inlet and a media outlet as well as a dosing needle. The dispensing needle is oscillatingly movable between an advance movement as a dispensing position and a reverse movement as a loading position. When the dosing needle moves backwards, the medium is pressed into the media chamber due to the pressure applied at the media inlet. During a feed movement, the medium is discharged from the media chamber via the media outlet.

According to the invention, the dosing unit 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 medium chambers are preferably identical in construction, but can differ from one another in their designs depending on the given structural requirements for the chamber metering valve.

Each of the dosing needles of the media chambers is coupled to a cam disk that is arranged on a common axis of rotation. Thus, at least two cam discs are provided - when the chamber metering valve is designed as a two-chamber metering valve. Correspondingly more chambers and thus cam disks are present in chamber metering valves with more than two chambers, such as three chambers with three cam disks on a common axis of rotation in a three-chamber metering valve. The axis of rotation is coupled to the drive unit, so that when the axis of rotation rotates, the dosing needles each oscillating between the feed movement as the dosing position and via their coupling to the respective cam disk the reverse movement than the loading position are movable. The at least two cam disks are shaped in such a way and arranged offset to one another on the axis of rotation such that a first metering needle is essentially advanced during a backwards movement of a second metering needle, so that the medium is continuously dispensed from the chamber metering valve. Thus, the feed movements of the first and second media chambers alternate and at any point in time during the dosing process, medium is pressed from one of the media chambers for dispensing from the chamber dosing valve into the media outlet - dosing takes place continuously.

A two-chamber system is always described below as a possible example of the invention. As already mentioned briefly above, however, 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, to arrange the cam discs on the axis of rotation by 120°, instead of being offset by 180° in a two-chamber system.

The Kammerdosierventil can advantageously be modular, with z. B. the drive unit form a first module and the dosing unit form a second module. 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 axis of rotation with the cam discs, etc. can be accommodated in a modular element, for example.

Furthermore, according to the present invention, a method for the continuous and low-pulsation metering of a viscous medium using a chamber metering valve is provided. A chamber metering valve as described above can advantageously be used to carry out the method.

In the method according to the invention, medium is fed under pressure to the chamber metering valve via a delivery unit. For this z. B. an inlet pressure of at least 10 bar (1 MPa) to a maximum of 50 bar (5 MPa) can be used. A media chamber with a metering needle is provided in the chamber metering valve, which is moved between a forward movement as a metering position and a backward movement as a loading position. During the backward movement of the dosing needle, the conveyor 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 metering valve, via which the medium leaves the chamber metering 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 in such a way and are arranged offset to 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 performs a forward movement while a second dosing needle performs a backward movement. Such a counter-rotating movement of the metering needles means that medium is pressed out of one of the medium chambers into the medium outlet at any point in time during the metering process, as a result of which the medium is metered out of the chamber metering valve continuously and with little pulsation.

To carry out the oscillating movement of the dosing needles between a forward movement and a backward movement, or between a dosing 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 be arranged rotated relative to one another on the axis of rotation, for example, in order to allow the feed movement of a first dosing needle to alternate with the feed movement of a second dosing needle. The displacement of the cam disc along the axis of rotation results from the structural distance between the dosing needles and the media chambers. By coupling the dosing needle to a peripheral contour of the cam disks and the eccentric mounting of the cam disks, the rotational movement of the cam disks is converted into a linear movement of the dosing needles and the at least two dosing needles can be moved back and forth in the media chambers in a coordinated manner. By coordinating the release of media from at least two media chambers into the media outlet of the chamber metering valve, the media flow can be controlled and continuously maintained.

The chamber metering valve according to the invention can also be referred to as a proportional metering valve, because the delivery of the medium, the metering, takes place proportionally to the path covered by the circumference of the cam disc that moves the metering needle in the advance position. The distance covered on the circumference of the cam disc on the way there is precisely converted into a continuous linear movement of the dosing needle due to a preferred design of the circumferential contour as an Archimedean spiral; the distance covered on the cam disk is converted directly proportionally into the distance covered by the dosing needle in the feed.

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

It should also be mentioned that there are similarly built two-chamber systems in pump and conveyor technology. In pump and conveyor technology, media are conveyed from a storage tank and, for example, introduced into a pipe system. Metering is not possible with such systems. It is important to note that in pump and conveyor technology, suction pressure is built up when the piston is pulled back, depending on the requirements placed on it. This suction pressure pulls the medium out of the container. The medium is then released, for example, into a line system. Unlike the present invention. In front of the metering valve according to the invention, the medium has to be pumped out of the reservoir using a pump or similar conveyor system and made available under pressure on the inlet side of the metering valve. By moving the piston back, the medium is pressed into the medium chamber due to the pressure applied on the input side - not sucked in, as is the case with conveyor systems. The invention lies in removing the medium already in the system from the system. With conveyor technology, medium is introduced into the system and with dosing technology, medium is removed from the system in a controlled manner. In a pump and conveying system, it is important that the medium in a system, e.g. B. a line system, is provided reliably and with constant pressure. With a dosing valve, the focus is on the dosed, locally limited or precise delivery, i.e. the delivery of a defined quantity. With the help of this dosing valve, grease quantities of 0.003 g can be dosed exactly. The systems are therefore, despite z. T. present apparent similarity of the system structures, not comparable, among other things because of the installation space and dead volumes, and certainly not interchangeable. When conveying and pumping, the focus is on maximizing the material flow, whereas when dosing, even the smallest possible dosing quantity units should still be delivered precisely. As a result, the dosing technology strives for the smallest installation spaces, the shortest supply line lengths and minimum dead space volumes. A specialist in dosing technology would therefore not consult pumping and conveying systems in order to solve a problem that arises.

In the present case, a sensitively adjustable dosing of small amounts is made possible, even for highly viscous lubricants. Media with higher viscosity bring various problems with them. Dosing is more difficult because high pressures of at least 10 bar have to be used. Even with such media, the media delivery must be stopped and started quickly. Sealing against material leakage is particularly important. For uninterrupted dosing, the viscous flow of lubricating grease must be kept running. Small sizes and small dead spaces are required for controlled, sensitively adjustable grease metering, as well as an integrated metering valve with the smallest chamber volumes.

The controlled dosing of small quantities requires special precautions: the dosing quantity can be adjusted more sensitively the smaller the supply spaces 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 drives must be designed in such a way that high rotational speeds can be used on the drive side and induced vibrations are avoided.

The smaller the volumes of the supply chambers, the shorter the required lengths of the stroke movements. This means that the camshafts and the cam disks, together with the resulting imbalances, become smaller or smaller. It can be reacted much more dynamically and a significantly improved running smoothness is achieved.

Due to the small size, disruptive effects such as pressure fluctuations or air pockets as well as other disruptive effects can have a greater impact. It is correspondingly important that the feed speeds of the supply are kept constant by a corresponding design of the cam disk, that a piston movement occurs briefly in the same direction during load changes and that smooth tangential transitions occur when the cam disk is designed, as provided for in the particularly preferred embodiment.

Fluctuations in pressure and media delivery are avoided by the fact that the movements of the pistons are jerk-free even at high rotational speeds on the drive side, which is achieved by a torque-free bearing of the pistons. 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 through a coupling that acts as directly as possible and is low-wear - torque-free storage, direct roller contact, no imbalances in the cam discs.

The camshaft is preferably controlled directly with the smallest axes. The direct connection to the motor ensures the shortest rise and fall times and allows highly dynamic control.

In the case of small dosing chambers, more fine-grained control is possible. At the same time, you have to work at a higher speed to enable large quantities and continuous dosing. The stroke movements are shorter in small chambers / installation spaces. This means that the cam discs (inertia) and their eccentricity (imbalance) are smaller, which makes low-vibration excitation of the pistons and a high number of revolutions/strokes possible and requires the piston movement to be implemented without wear.

The present invention brings with it numerous advantages, such as e.g. T. already explained above. The metering valve requires little maintenance and is very compact. Continuous dosing is possible because one chamber is filled and the other chamber is ejected at the same time. This makes it possible to apply beads of lubricating grease, i.e. in principle the endless application of lubricating grease. In exactly the same way, however, a selective delivery of the lubricant is possible. This depends solely on the operation of the system.

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

In an exemplary embodiment of the chamber metering valve according to the invention, the metering needles are prestressed in the direction of the cam discs by means of a spring. Thus, the needles are always pressed against a peripheral contour of the cam and the needles are coupled to the cam. A compression spring can be used for this, for example, which is supported on the one hand on a coupling end of the metering needle pointing towards the cam disk and on the other hand on the media chamber or a housing of the chamber metering valve. The spring ensures a continuous transmission of drive between the cam and the dispensing needle.

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

Furthermore, the dosing needle can have a roller at its coupling end, which rolls against the peripheral contour of the cam disk. During the rotation of the cam, the roller thus rolls smoothly on the peripheral contour and transmits the drive movement the cam disk on the dosing needle to press the medium out of the media chamber during the dosing position or to release the chamber volume to fill the media chamber during the loading position.

Furthermore, the dosing needles are preferably mounted in the media chambers in a torque-free manner. A seal package and/or bearings can be provided for this purpose, 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 with its output shaft directly or indirectly such. B. via a belt to be coupled to the axis of rotation. Electric motors are small and can generate high speeds. The motor is advantageously designed as a modular unit and can be arranged directly on the dosing unit.

In a further exemplary embodiment of the chamber metering valve according to the invention, a non-return valve can be provided at the media inlet to the media chamber, which prevents backflow from the media chamber into the supplying conveyor system. A medium that has been filled into the media chamber is therefore only released via the media outlet of the chamber.

Furthermore, a control valve, preferably a non-return valve, is advantageously provided in each media outlet of each individual chamber, which prevents backflow into the respective media chamber when the metering needle of an adjacent chamber moves forward or when the metering needle of this chamber moves backwards.

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 referred to as a tappet, in the present case usually referred to as a dosing needle. This means that the lubricating grease or other type of medium in the system is drawn in by one piston into the piston chamber, usually referred to here as the media chamber, while the other piston is in ejection mode and ejects the medium again. The ejection by both pistons takes place in one and the same outlet channel and ends in the common media outlet. In a particularly preferred embodiment of the invention, the cam disc is designed in such a way that the ejection interval of both pistons overlaps. With a correspondingly precise design of the cam discs, also referred to as cams, the total output is completely uninterrupted, i.e. not only low pulsation but pulsation free. It was shown that with precise alternating operation, ie when one piston is in the loading interval while the other is in the ejection interval, low-pulsation dosing is possible, but that an exactly uniformly thick or wide bead of grease cannot be ejected . Instead, small deviations in the amount of grease have been observed, ie the bead becomes somewhat uneven. By providing an overlap interval, this problem is eliminated; shortly before the piston that is 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 overrun in the outlet, which v. a. with viscous media that are introduced with high working pressures could be a problem. The shut-off valve at the media outlet is particularly important, as it promotes overrun 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 configurations and properties of the cam discs are explained below:

1. 1. The outward path, ie the path on which the ejection, ie the forward movement of the dosing needle, takes place, is longer than the return path, ie the path on which the media chamber is loaded. The different path lengths are achieved by different radii. On the way there, an Archimedean spiral is preferably used. A spiral translates to exactly the same linear path per degree. As a result, the ram always moves forward the same way. In this way, an even discharge is possible at all.
2. 2. On the way back, however, the exact shape is irrelevant, because the piston is reset by a spring and it is only important that the chamber is completely filled at the new ejection time. As a result, a simple radius is preferred for the return path.
3. 3. The area of overlap in which both pistons meter is preferably a simple radius. The spiral of the advance ends with the beginning of the overlapping area. A person skilled in the art is able to determine the radius of the overlap area experimentally, e.g. B. by adjusting and changing the radius until the desired uninterrupted dosing takes place.
4. 4. It is metered, i.e. ejected, in a section of more than 180 degrees of the circumference of the cam disk. Accordingly, the return path is less than 180 degrees.

The present multi-chamber metering valve has various advantages, such as T. already mentioned above. Due to the cam design described above, there are other advantages, namely: No referencing is necessary. It doesn't matter what state the system is in when it's stopped, it can just keep going. It also makes no difference whether an identical quantity of lubricant is to be dispensed in each cycle or whether, for example, a program is to be run through in which, for example, two individual drops are to be dispensed alternately and then metered continuously over a short distance. None of this plays a role for the present system, since it is completely free of referencing. It is an endless system. The system can be restarted at any point. Even if the emergency stop is actuated, the system can easily continue to be operated.

The common media outlet can advantageously have a non-return valve or a control valve, preferably a non-return valve, for regulating the delivery of the medium from the chamber metering valve and in particular for preventing backflow into lines and channels of the metering valve leading to the common media outlet.

The non-return valves in the media inlets, the control valves or non-return valves, in the media outlets and in the media outlet can together form a valve system for regulating the continuous flow of media and thus the amount of media applied.

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

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

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

In order to ensure that the medium escapes continuously from the media chambers, the control valve or the non-return valve in the media outlets is designed in such a way that a minimum pressure of 30 bar, preferably 35 bar, particularly preferably over 40 bar, to Opening the control valve or check valve is required. At these pressures, it can be ensured that there is sufficient thrust to continuously press the medium into the media outlet and to be able to release a defined quantity of the medium from the chamber metering valve.

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

In a preferred embodiment, three seals in the form of O-rings are provided in each media chamber. The combination of the same in series ensures the required high tightness of the system with the demanding process requirements, as described here, v. a. the high working pressures. The complete set of seals is particularly preferably mounted in a sleeve and at the same time serves to guide the dosing needle.

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

According to a further aspect of the present invention there is further provided a metering system comprising a chamber metering valve as described above and a control unit for the chamber metering valve. The control unit can be used, for example, to set a rotational speed of the axis of rotation; B. controlled depending on an applied pressure, it can be determined a temperature for the media chambers and / or the medium pressure at the media inlet can be adjusted. In particular, the chamber metering valve can be controlled as a function of the viscosity of a medium, so that a reproducible delivery of a preset amount of media can be variably determined in a defined time window.

Character brief 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 can be understood more easily with reference to the accompanying figures, which present an advantageous embodiment of the chamber metering valve by way of example, without restricting the present invention to these. The figures show:

Figure 1:

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

Figure 2:

the chamber metering valve figure 1 in a first side view;

Figure 3:

another side view of the chamber metering valve figure 1 ;

Figure 4:

a front view of the chamber metering valve of FIG figure 1 ;

Figure 5:

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

Figure 6:

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

Figure 7:

a third sectional view through the drive unit of the chamber metering valve figure 1 (cut C - C in figure 3 );

Figure 8:

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

Figure 9:

shows an exploded view of various components of the chamber metering valve figure 1 ; and

Figure 10:

a detailed view of a preferred embodiment of a cam for use in a chamber metering valve figure 1 , at the same time a schematic representation of a method according to the present invention based on rotation phases of the cam on the axis of rotation of the chamber metering valve 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 denote "right", "left", "down" and "up" directions in the drawing to which reference is made. The terms "inside", "outside", "below", "above", "left", "right" or the like are used to describe the relative arrangement of designated parts, the movement of designated parts relative to one another, and directions toward or away from the geometric center of the invention and designated parts thereof as shown in the figures. This spatial relative information also includes positions and orientations other than those shown in the figures. For example, if a part shown in the figures is turned over, elements or features described as "below" are then "above". The terminology includes the words expressly mentioned above, derivatives thereof and words of similar import.

In order to avoid repetition in the figures and the associated description of the various aspects of the invention, certain features should be understood as being common to various aspects and exemplary embodiments. The omission of an aspect in the description or a figure does not imply that this aspect is missing in the associated exemplary embodiment. Rather, such omission may serve for clarity and to avoid repetition. In this context, the following stipulation applies to the entire further description: If reference numbers are contained in a figure for the purpose of clarity in the drawing, but are not mentioned in the directly associated description text, reference is made to their explanation in the preceding figure descriptions. If, in addition, in the descriptive text belonging directly to a figure, reference signs are mentioned which are not contained in the associated figure, then reference is made to the preceding and following figures. Similar reference numbers in two or more figures indicate similar or identical elements.

The invention is described below with reference to the single exemplary embodiment, including 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 is shown. The embodiment shown is particularly suitable for the metering and application of lubricants such. B. fats, as they are used in machine, automation and process technology. In principle, a chamber metering valve according to the invention can also be used for metering oils, as well as for almost solid, highly viscous and sticky media. In figure 10 a particularly preferred design of a cam disc is shown, as can be preferably used in a chamber metering 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 includes a drive unit 1 and a metering unit 2. Details of the chamber metering valve 100 are based on FIG figure 9 described.

The dosing unit 2 has a media inlet 3 for supplying the chamber metering valve 100 with a medium to be applied from a reservoir (not shown) and a media outlet 4 for the continuous delivery of the medium from the chamber metering valve 100 . Connections for an alternative media input 3' and an alternative media output 4' are provided in order to be able to do justice to the structural conditions at the place 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 or 7' and a media outlet 8 or 8'. 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. Each media chamber also has a dosing needle that is movably mounted in the chamber, ie 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 fixedly attached to the dosing needles 9 and 10 at the coupling end 12, 12' and 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 stop 16, 16' fixed to the housing. The spiral springs 15, 15' tension 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' to the media chambers 5 and 6, respectively. In the cut of figure 2 the non-return valve 17 is inserted in the media inlet 7', which prevents the medium from flowing back out of the media chamber in the direction of the storage vessel. Such a 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 exit of the medium from the respective media chamber.

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

The non-return valves and control valves prevent entrainment or after-running in the media outlet and in the media outlets, which can be a problem, especially with viscous media that are fed with high working pressures. Above all, the valve at the media outlet prevents overrun and drip-free media dosing.

The coupling ends 12 of the dosing needles 9 and 10 are aligned in the direction of an axis of rotation 20 and perpendicular to it. The axis of rotation 20 is rotatably mounted in bearings 21 and 21 ′ in the housing of the dosing unit 2 . A first cam disk 22 , which interacts with the first dosing needle 9 , and a second cam disk 23 , which interacts with the second dosing needle 10 , are arranged on the axis of rotation 20 and rotate together with the axis of rotation 20 . The cam discs 22 and 23 are eccentric, rotated through 180° to one another and offset in the longitudinal direction on the axis of rotation 20 . The axis of rotation 20 and the cam disks 22 and 23 together form a type of camshaft which acts on the dosing needles 9 and 10 of the media chambers 5 and 6 . For this purpose, the dosing needles 9 and 10 with their respective rollers 14 rest against a peripheral contour 24 or 24' of the cam disk 22 and 23, the rollers 14 being pressed by the compression springs 15 against the peripheral contours 24 or 24'. The dosing needles 9 and 10 are thus coupled to the cam disks 22 and 23 via the rollers 14 . The axis of rotation 20 is in turn coupled to the drive unit 1 in order to be able to be driven in rotation by it.

How 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 for guiding a movement of the dosing needles 9 and 10, which each adjoin the media chambers 5 and 6. The guide sleeves 30, 30' are used for the torque-free mounting of the dosing needles.

At the same time, the guide sleeves 30, 30' have the function of a sealing package. In the preferred embodiment shown, there are three seals 31, 33, 34 or 31, 33' and 35' in each guide sleeve 30, 30', which seal an intermediate space between the dosing needle and 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 or 30' and thus each form an independent seal. The seals mentioned together form a seal package for sealing between the media chamber and the dosing needle. The combination of the seals 31, 33, 35 or 31', 33', 35' ensures the high level of tightness required for demanding process requirements.

To vent each media chamber 5 and 6 is a vent 32, 32 ', z. B. a vent valve provided.

For the metered dispensing of a viscous medium, the metering needles 9 and 10 of the metering unit 2 are driven by the drive unit 1 by rotating the axis of rotation 20 to oscillate between a forward movement as a metering position and a backward movement as a loading position. The axis of rotation 20 is in turn driven by the drive unit 1 . For this purpose, the two cam disks 22 and 23 are shaped in such a way and arranged offset to one another on the axis of rotation 20 such that essentially a forward movement of the 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 metering valve. In the loading position, i. H. When the dosing needles 9 and 10 move backwards, medium from a reservoir is supplied to the medium chambers 5 and 6 under pressure. In the dosing position, i. H. With a forward movement of the dosing needles 9 and 10, medium is pressed out of the respective medium chamber. Due to the counter-rotation of the dosing 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 feed movement 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 rotational speed of the axis of rotation 20 .

figure 8 shows a three-dimensional partial section of the chamber metering valve with the axis of rotation 20, which carries the first cam disk 22 and the second cam disk 23, and the metering needles 9 and 10 and their coupling by means of the rollers 14 to the cam disks 22 and 23.

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

In order to control the dosing and application of the medium from the chamber metering valve, a control unit can be provided on the chamber metering valve or remotely from it, which controls, for example, the drive unit and the valves of the chamber metering valve. Furthermore, a device for heating and/or cooling the medium in the medium chambers can be provided, which can also be regulated via the control unit. The media chambers are preferably machined from an aluminum block. Concomitant heating or cooling is rapidly transmitted to the medium through the aluminum.

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

In figure 10 only one cam 22 is shown. It has an eccentric design, as can be clearly seen. The peripheral contour 24 has different sections, which divides the rotation of the cam about the axis of rotation 20 into different phases of rotation. The individual rotation phases can be distinguished from each other based on their geometric design. A forward sector 40 for the forward movement and a return sector 41 for the backward movement of the dosing needle can be distinguished as the main sections. The advance 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 illustrated preferred embodiment, a peripheral contour section of the forward sector 40 differs from a peripheral contour section of the return sector 41 in such a way that the feed movement lasts longer than the backward movement - the path of the forward sector 40 is longer than the path of the return sector 41.

Due to the above path difference, there is an overlapping sector 42 in which both dosing needles 9 and 10 simultaneously perform a feed movement for a short period of time. The two dosing needles 9 and 10 move briefly in the same direction. During this period, one cam disk has already started the feed movement by crossing the low point 45, while the other cam disk is at the end of the feed movement, in the overlapping sector 42. This avoids a dead center in the media output during the reversal of movement.

The peripheral contour 24 can be divided into different sections, which can be distinguished on the basis of their geometric properties.

As already mentioned above, the forward sector 40 extends from the low point 45 to the high point 44. In the first section of this path, the peripheral contour 24 is a straight line - reference number 43. This is followed by a large section which has the shape of an Archimedean spiral - reference number 46 In this section, the path length of the cam disk is converted directly proportionally into the path of the dosing needle. Towards the high point 44 there is a transition radius from the forward flow 40 to the return flow 41 - the overlapping sector 42.

The return sector 41 extends from the high point 44 to the low point 45. This is for the most part a simple radius. Another radius is provided immediately before the low point 45 - the transition radius from the return to the forward 47.

As already mentioned, the peripheral contour in the main part of the forward sector 40 is advantageously designed in a spiral shape (section 46) for a continuous feed movement of the dosing needle. This means that the radius increases continuously from the beginning of the advance phase to the end of the advance phase. At the same time, a radius of the peripheral contour in the return sector 41 can be oval-shaped. 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. There is thus a symmetrical change in radius around the center of the retrace phase.

figure 10 clarifies the special shape of the cam disks 22 and 23 mounted on the axis of rotation 20 in a preferred exemplary embodiment of a chamber metering valve 100 according to the invention. that the peripheral contour 24, 24' is a type forms a semi-oval. The shape leads to a largely counter-rotating movement of the dosing needles 9 and 10, as a result of which the emptying and refilling of each media chamber 5 and 6 takes place alternately in a single rotation of the axis of rotation 20. In addition, the peripheral contour 24, 24′ in the transition sectors 42 and 47 is shaped in such a way that there is an overlapping area for the movement of both dispensing needles, in which there is a targeted, short-term feed movement of the dispensing needles in the same direction in the media chambers. 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 dosing needle in the media chamber and thus to its emptying. At the end of the forward sector 40, it is followed by the already mentioned overlapping sector 42. After that, when a high point 44 is reached, a return phase via the return sector 41 starts, during which the dosing needle moves backwards in the media chamber and this is again filled with medium from the reservoir. The cycle ends when the low point 45 is reached. The tangential 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.

Reference List

1

drive unit

2

dosing unit

3, 3'

media input

4, 4'

media exit

5

first media chamber

6

second media chamber

7, 7'

media inlet

8, 8'

media outlet

9

first dosing needle

10

second dosing needle

11, 11'

end of feed

12, 12'

coupling end

13, 13'

coupling sleeve

14, 14'

role

15, 15'

spiral spring

16, 16'

attack

17

check valve

18

control valve

19

control valve

20

axis of rotation

21, 21'

warehouse

22

first cam

23

second cam

24, 24'

perimeter contour

30, 30'

guide sleeve

31, 31'

poetry

32, 32'

ventilation

33, 33'

poetry

34, 34'

poetry

40

forward sector

41

rewind sector

42

overlap sector

43

Just

44

peak

45

rock bottom

46

spiral

47

Transition radius from return to forward

50

electric motor

51

output shaft

52

first drum

53

second drum

54

backing plate

55

transmission belt

56

cover

57

electrical connection

100

chamber metering valve

Claims (15)

Chamber metering valve (100) for the metered delivery of a viscous medium with a metering unit (2) and a drive unit (1) which are connected to one another,
wherein the dosing unit (2) comprises at least one media inlet (3), at which the medium is supplied to the dosing unit under pressure, and a media outlet (4), via which the medium is discharged from the chamber metering valve,
wherein the dosing unit comprises a media chamber (5) with a media inlet (7) and a media outlet (8),
wherein the media chamber (5) comprises a dosing needle (9) which can be moved in an oscillating manner between a forward movement as a dosing position and a backward movement as a loading position,
wherein during the backward movement of the dosing needle (9) the medium is pressed into the medium chamber (5) due to the pressure applied at the medium inlet (3),
characterized in that
the dosing unit comprises at least two media chambers (5, 6) with a media inlet (7, 7') and a media outlet (8, 8'),
wherein the media outlets (8, 8') of the at least two media chambers (5, 6) open into the media outlet (4) of the dosing unit,
wherein each media chamber (5, 6) comprises a dosing needle (9, 10), each of which is coupled to a cam (22, 23), and the cams (22, 23) are arranged on a common axis of rotation (20) which is the drive unit (1) is coupled so that when the rotation axis (20) rotates, the dosing needles (9, 10) can each be moved in an oscillating manner between the forward movement as the dosing position and the backward movement as the loading position,
wherein the at least two cam disks (22, 23) are shaped and offset from one another on the axis of rotation (20) so that essentially a forward movement of a first dosing needle (9) takes place during a backward movement of a second dosing needle (10), so that a continuous The medium is discharged from the chamber metering valve. Chamber metering valve (100) according to claim 1,
characterized in that
the dosing needles (9, 10) are pretensioned in the direction of the cam discs (22, 23) by means of a spring (15). Chamber metering valve (100) according to claim 1 or 2,
characterized in that
the dosing needles (9, 10) have a roller (14) at a coupling end (12), which rolls against a peripheral contour (24, 24') of a cam disc (22, 23). Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
the drive unit is designed as an electric motor which drives the axis of rotation directly or indirectly. Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
a non-return valve (17) is provided at the media inlet (7, 7') to the media chamber (5, 6) and prevents backflow from the media chamber (5, 6). Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
the media outlets (8, 8') from the media chambers (5, 6) open into a common media outlet (4) from the dosing unit (2) and a control valve or a check valve (18) is provided in each media outlet (8, 8'). , which prevents backflow into the respective media chamber (5, 6). Chamber metering 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 area of the common media outlet (4). Chamber metering valve (100) according to claim 6 or 7,
characterized in that
the control valve or check valve (18) is designed in such a way that a minimum pressure of 30 bar, preferably 35 bar, particularly preferably 40 bar, is required in the media chamber to open the control valve or check valve (18). Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
the dosing unit (2) for each dosing needle (9, 10) a guide sleeve (30) for guidance the oscillating movement of the dosing needle (9, 10), in which at least two independent sealing devices for sealing between the media chamber (5, 6) and the dosing needle (9, 10) are provided. Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
each media chamber (5, 6) has a maximum volume of 5,000 mm ³ , in particular 1,000 mm ³ , preferably 500 mm ³ , even more preferably 200 mm ³ or less. Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
the temperature of the medium in the media chambers (5, 6) can be controlled by means of a heating or cooling element. Chamber metering valve (100) according to any one of the preceding claims,
characterized in that
a peripheral contour (24, 24') of the cam discs (22, 23) has a forward sector for the feed movement and a return sector for the backward movement of the thrust piston, with a contour section of the forward sector differing from a contour section of the return sector in such a way that the feed movement lasts longer as the backward movement. A dosing system comprising a chamber metering valve (100) according to claim 1 and a control unit for the chamber metering valve. Dosing system according to the preceding claim,
characterized in that
the control unit controls a rotational speed of the axis of rotation (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. Method for the continuous and low-pulsation metering of a viscous medium using a chamber metering valve (100),
the medium is fed under pressure to the chamber metering valve via a delivery unit,
wherein a medium chamber (5) in the chamber metering valve has a metering needle (9) which is moved between a forward movement as a metering position and a backward movement as a loading position,
whereby during the backward movement of the dosing needle (9) the delivery unit pushes the medium into the media chamber (5) and during the forward movement the dosing needle (9) pushes the medium out of the media chamber (5) into a media outlet (4) via which the medium chamber metering valve leaves,
characterized in that
at least two media chambers (5, 6) are provided, the dosing needles (9, 10) of which are each moved between the dosing position and the loading position via a cam disk (22, 23) arranged on a common axis of rotation (20),
wherein the cam disks (22, 23) are shaped and offset from one another on the axis of rotation (20) so that the dosing position of a first dosing needle (9) essentially alternates with the loading position of a second dosing needle (10),
so that medium is pressed from one of the medium chambers (5, 6) into the medium outlet (4) at any point in time during the dosing process,
whereby the medium is dosed continuously and with little pulsation from the chamber dosing valve.

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