WO2020069909A1 - Dosiersystem mit kühleinrichtung - Google Patents
Dosiersystem mit kühleinrichtungInfo
- Publication number
- WO2020069909A1 WO2020069909A1 PCT/EP2019/075644 EP2019075644W WO2020069909A1 WO 2020069909 A1 WO2020069909 A1 WO 2020069909A1 EP 2019075644 W EP2019075644 W EP 2019075644W WO 2020069909 A1 WO2020069909 A1 WO 2020069909A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- actuator
- piezo actuator
- cooling
- dosing
- movement mechanism
- Prior art date
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
- B05C5/02—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
- B05C5/0225—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work characterised by flow controlling means, e.g. valves, located proximate the outlet
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/10—Storage, supply or control of liquid or other fluent material; Recovery of excess liquid or other fluent material
- B05C11/1002—Means for controlling supply, i.e. flow or pressure, of liquid or other fluent material to the applying apparatus, e.g. valves
- B05C11/1034—Means for controlling supply, i.e. flow or pressure, of liquid or other fluent material to the applying apparatus, e.g. valves specially designed for conducting intermittent application of small quantities, e.g. drops, of coating material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
- B05C5/001—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work incorporating means for heating or cooling the liquid or other fluent material
Definitions
- Dosing system with cooling device The invention relates to a dosing system for a dosing agent with a nozzle, a feed channel for dosing agent, an ejection element, an actuator unit coupled to the ejection element and / or the nozzle with a piezo actuator and a cooling device.
- the invention further relates to a method for operation and a method for producing such a metering system.
- Dosing systems of the type mentioned at the outset are usually used to specifically meter a medium to be metered, typically a liquid to viscous metering agent.
- a medium to be metered typically a liquid to viscous metering agent.
- microdosing technology it is often necessary that very small quantities of a dosing agent are precise and contactless. H. can be applied to a target surface without direct contact between the dosing system and a target surface.
- Such a contactless process is often referred to as the “jet process”.
- a typical example of this is the dosing of adhesive dots, solder pastes etc. when assembling printed circuit boards or other electronic elements, or the application of converter materials for LEDs.
- An important requirement here is to deliver the dosing agents to the target surface with high precision, i.e. at the right time, in the right place and in a precisely dosed quantity.
- This can be done, for example, by dispensing the dosing agent drop by drop through a nozzle of the dosing system.
- the medium only comes into contact with an interior of the nozzle and a, mostly front, area of an ejection element of the metering system.
- a preferred method here is the ejection of individual droplets in a kind of “ink-jet method”, as may be the case. a. is also used in inkjet printers.
- the size of the droplets or the amount of medium per droplet can be predicted as precisely as possible by the structure and the control as well as by the effect of the nozzle.
- the dosing substance can also be sprayed on in a jet.
- a movable ejection element (usually a plunger) can be arranged in the nozzle of the dosing system.
- the ejection element can be pushed forward in the interior of the nozzle at a relatively high speed in the direction of a nozzle opening or outlet opening, as a result of which a drop of the medium is ejected and then withdrawn again.
- the nozzle of the dosing system itself can be moved in an ejection or retraction direction.
- the nozzle and an ejection element arranged in the interior of the nozzle are moved in a relative movement towards or away from one another. The relative movement can either take place solely by moving the outlet opening or the nozzle, or at least in part also by moving the ejection element accordingly.
- the ejection element can also be brought into a closed position by firmly connecting it to a sealing seat of the nozzle opening in the nozzle and temporarily remaining there. In the case of more viscous dosing substances, it may also be sufficient for the ejection element to simply be in the retracted position, i.e. H. remains away from the sealing seat without a drop of the medium escaping.
- the present invention can be used in all of the aforementioned variants, regardless of the specific ejection principle, ie. H. with a jet process, an open ink-jet process, a classic closure element or a movably designed nozzle. The movement of the ejection element and / or the nozzle usually takes place with the aid of an actuator system of the metering system.
- the dosing system typically comprises a movement mechanism coupled to the actuator system and the ejection element.
- the movement mechanism can e.g. B. be realized by means of a lever on which the actuator system is supported.
- the lever itself can rest on a lever bearing and can be tilted about a tilt axis in such a way that the movement of the actuator system is transmitted to the ejection element via a contact surface of the lever.
- the movement mechanism can also be designed to transmit the force generated by the actuator system for moving the nozzle.
- the actuator system can be implemented in various ways, with piezo actuators preferably being used in particular in applications which require a very fine dosage resolution.
- Piezo actuators which are also referred to as piezoelectrically operated actuators, have compared to other types of actuators, e.g. B. hydraulically, pneumatically and / or electromagnetically operated actuators, the advantage of very precise and above all fast controllability.
- Piezo actuators are advantageously distinguished by extremely short reaction or response times, which are usually well below the corresponding values of other actuator principles.
- Another advantage is that piezo actuators take up comparatively little space within a metering system compared to other types of actuators. Piezo actuators thus offer an efficient solution for the operation of dosing systems, especially for very fine dosing requirements.
- piezo actuators are components in which large power losses are implemented, which can cause the piezoelectric material to become very hot. Since piezo actuators have a temperature-dependent behavior, heating of the actuator material can equally influence the longitudinal expansion of the piezo actuator in the non-expanding (non-expanded) state and the deflection of the piezo actuator under voltage. In addition to the piezo actuator, the components of the movement mechanism can also heat up during operation of the dosing system due to the frictional heat that arises, especially with high-frequency dosing requirements.
- a thermal expansion of one or more of the above-mentioned components can lead to an undesirable change in the lifting process of the ejection element, so that the amount of dosing agent dispensed during operation of the dosing system can increasingly deviate from a desired value. Consequently, the temperatures of the piezo actuator and the movement mechanism can have a direct impact on the precision of the dosing system.
- the entire piezo actuator can be flowed around with compressed room air or compressed air, since compressed air is already available in most dosing system systems.
- the movement mechanism is not subjected to a separate flow, but only the exhaust air from the piezo actuator flows around it. It has turned out to be disadvantageous that as the ambient temperature of the dosing system increases, the compressed air can no longer dissipate enough heat from the piezo actuator to permanently keep the piezo actuator and other temperature-sensitive areas of the dosing system below a temperature critical for the precise operation of the dosing system hold.
- a metering system according to the invention for a liquid to viscous metering agent comprises at least one nozzle, a feed channel for metering agent, an ejection element, an actuator unit coupled to the ejection element and / or the nozzle with at least one piezo actuator to move the ejection element and / or the nozzle, and a cooling device.
- tappet is used as a synonym for an ejection element, without restricting the invention thereto.
- the dosing agent can be dispensed from the dosing system according to the invention in one of the ways explained at the outset, ie. H. the dosing system is not limited to a specific ejection or functional principle.
- an ejection element which can be moved at relatively high speed for ejecting the dosing material from the nozzle can be arranged in the nozzle of the metering system (in particular in the area of the nozzle, for example, just before the outlet opening).
- an outlet opening of the metering system according to the invention can be designed to be movable. Nevertheless, in the following, for the sake of clarity, it is assumed that the dosing agent is dispensed by means of a movable ejection element, e.g. B. a pestle. However, the invention is not intended to be so limited.
- the actuator unit comprises at least one piezo actuator and a movement mechanism which interacts functionally with the piezo actuator and which, as explained at the beginning, can preferably comprise at least one lever and one lever bearing.
- a fluidic unit of the dosing system is to be distinguished from the actuator unit, which comprises the components that come into contact with the dosing substance.
- the movement mechanism of the actuator unit is designed to functionally couple the ejection element to the at least one piezo actuator of the metering system.
- the coupling takes place in such a way that the forces and movements exerted by the piezo actuator are passed on in such a way that the desired movement of the ejection element results therefrom Dispensing of the dosing agent from the nozzle results.
- the movement mechanism thus represents a, preferably multi-part, force-transmitting coupling, at least temporarily, in order to convert the deflection of the piezo actuator into a, preferably vertical, movement of the ejection element.
- the coupling between the movement mechanism and the ejection element is preferably not a fixed coupling. This means that the two components are preferably not screwed, welded, glued, etc. for coupling.
- the metering system comprises a cooling device with a feed device for feeding a precooled cooling medium into a housing of the metering system, in particular into a housing of the actuator unit.
- the housing of the actuator unit limits the actuator unit with respect to an ambient atmosphere of the metering system, i. H. it forms a covering of the actuator unit and therefore comprises at least one piezo actuator and the movement mechanism of the metering system.
- the feed device has a number of, that is to say one or more, connection or coupling points for an (external) cooling medium supply line in a region of the housing, as well as a connection to the (respective) coupling point and into an interior of the housing extending feed channel arrangement.
- the feed device can furthermore comprise a number of components for regulating a volume flow and / or pressure of the cooling medium flowing into the housing, for example: B. a pump or a proportional valve, and possibly other components.
- the cooling device is designed for direct, predominantly selective cooling of at least a partial area of the piezo actuator and / or the movement mechanism of the actuator unit coupled to the piezo actuator by means of the pre-cooled cooling medium.
- “Direct” cooling of a sub-area means that the respective sub-area, in particular its surface, is the focus of the cooling.
- the respective sub-area can preferably be flowed or blown directly with the pre-cooled cooling medium.
- the cooling of a partial area in the housing itself takes place. H. directly on the spot". The cooling is therefore not carried out “indirectly” by cooling the housing or parts of it from the outside (eg by means of conduction).
- the cooling device may include flow directing elements within the housing, e.g. B. separately controllable flow channels, baffles, fans, etc. in order to direct the cooling medium to a specific sub-area. Accordingly, there can be areas of the surface of the piezo actuator or movement mechanism that are not included in the partial area to be cooled and are therefore excluded from direct cooling.
- a number of sub-areas ie one or more sub-areas, which in total essentially comprise the entire surface of the piezo actuator or the components of the movement mechanism, are acted upon directly by the cooling medium, so that the invention below, without limitation, will be described based on this embodiment.
- a pure flow of other areas of the metering system with the cooling medium as (partial) areas of the piezo actuator or the movement mechanism, for. B. an outside of the housing is not covered by the invention.
- the areas of the housing lying inside the housing, for. B. the walls, which form a chamber surrounding the piezo actuator (actuator chamber) and a chamber surrounding the movement mechanism, are not the goal of direct cooling.
- These areas or surfaces of the metering system, which are not encompassed by a sub-area to be cooled, are therefore not specifically flowed or blown onto by the cooling medium, but rather only “flowed with”. This means that the cooling medium necessarily passes through these areas on the way from the feed device to an outlet opening from the housing, the areas themselves not being the focus of direct cooling by the cooling device.
- the cooling device can be designed to selectively cool only a number of partial areas of one or more piezo actuators. This means that the movement mechanism would not be affected by the direct cooling.
- the direct cooling could also be directed only to one or more sub-areas of the movement mechanism, the piezo actuator not being included in the direct cooling.
- the piezo actuator and the movement mechanism can therefore be cooled separately by means of the cooling device according to the invention.
- the cooling device can also be designed to be a number to cool parts of the piezo actuator and the movement mechanism directly as a unit, as will be explained later.
- a precooled cooling medium is to be understood to mean that the cooling medium, at least at the time of entry into the housing, has a predefinable (target) temperature.
- target the (target) temperature of the cooling medium is lower, and under certain circumstances also significantly lower, than an ambient temperature of the metering system.
- the “real” cooling according to the invention with a cooled cooling medium thus differs from a flow around the piezo actuator with compressed room air for “cooling purposes”.
- the cooling medium is subjected to cooling or heat removal before being fed into the housing, ie heat or thermal energy is specifically removed from the cooling medium, for example by means of a cooling device of the cooling device, as will be explained later
- the pre-cooled cooling medium can have a (target) temperature of at most 18 ° C., preferably at most 10 ° C., particularly preferably at most 1 ° C., at the time of entry into the housing.
- the process heat generated during operation of the metering system is dissipated particularly effectively by the piezo actuator or movement mechanism.
- the “real” and targeted or directional cooling according to the invention leads to a significant improvement in the cooling capacity, so that with the same volume flow of the cooling medium, significantly more thermal energy per unit of time is supplied directly by one cooling surface can be dissipated.
- the particularly temperature-sensitive components of the dosing system e.g.
- piezo actuator and movement mechanism can be cooled even at high outside temperatures in such a way that the undesired, thermally induced expansion of these components explained at the outset is prevented and the high precision of the dosing system is permanently high is achieved. Due to the particularly effective cooling, the dosing system can be operated with a maximum dosing frequency even at high ambient temperatures. Furthermore, the temperature-sensitive components of the metering system can be cooled selectively and selectively by means of the cooling device, cooling of the other components or of the housing itself being unnecessary. The consumption of pre-cooled cooling medium can thus be reduced.
- a dosing system for dosing dosing agent comprising a nozzle, a feed channel for dosing agent, an ejection element, an actuator unit coupled to the ejection element and / or the nozzle, and a cooling device
- a precooled cooling medium is fed to the cooling device by means of a feed device.
- one or more partial areas of the piezo actuator are cooled directly by the cooling device by means of the pre-cooled cooling medium.
- At least a portion of a movement mechanism of the actuator unit coupled to the piezo actuator is directly cooled by the cooling device by means of the precooled cooling medium, that is to say the cooling medium flows in a targeted or focused manner or is blown onto it.
- the cooling medium flows in a targeted or focused manner or is blown onto it.
- a number of sub-areas which, taken together, comprise the surface of the piezo actuator and / or the movement mechanism can be cooled directly.
- the cooling device can be controlled and / or regulated accordingly by means of a control and / or regulating unit coupled to the metering system, as will be explained later.
- the dosing system is equipped with a cooling device.
- the cooling device is equipped with a feed device for feeding a pre-cooled cooling medium into a housing of the metering system.
- the metering system in particular the cooling device, is designed such that at least a partial area of the piezo actuator and / or a movement mechanism coupled to the piezo actuator can be cooled directly by means of the precooled cooling medium during operation of the metering system.
- the at least one piezo actuator of the metering system can comprise an actuator housing which is at least partially flexible, e.g. B. a wrinkled metal bellows in which is hermetically encapsulated a number of piezo elements.
- the actually “active” piezo actuator preferably a monolithic piezoceramic multilayer actuator with a number of stacked layers of a piezoelectrically active material
- a separate actuator cover as an actuator housing
- the actuator casing is permanently connected to the piezo stack encapsulated therein or the two components form a functional unit, the actuator casing is considered within the scope of the invention as a component of the piezo actuator.
- the actuator casing of the at least one piezo stack is preferably designed so that even during operation of the metering system, ie when the piezo stack is deflected, no substances or substances can penetrate the actuator casing from the outside inwards or in the opposite direction.
- the actuator cover is designed such that it is impermeable to water or moisture in general. Due to the encapsulation, in this embodiment of the invention, at least a partial area of an outer surface or outer side of the actuator shell facing away from the piezo stack, preferably its entire surface, is directly blown or blown with cooling medium.
- a heat-conducting medium surrounding the piezo stack for dissipating heat from a surface of the piezo stack can be arranged in the actuator shell.
- the heat-conducting medium can preferably be designed in such a way that heat is transferred from the piezo stack surface to the actuator casing, for example by means of construction and / or convection.
- B. a metal body is transferred.
- the piezo stack surface can preferably represent a heat transfer surface for the heat source, it being possible for at least a portion (to be cooled) of the actuator casing to be designed as a heat transfer surface for the heat sink.
- the actuator casing can also comprise a medium for suppressing moisture.
- a metering system with at least one hermetically encapsulated piezo stack it can advantageously be achieved that the piezoelectrically active material is largely completely shielded from harmful external (environmental) influences of the metering system, in particular moisture, even during operation of the metering system, the “longevity “The piezo actuator is significantly improved.
- the particularly effective cooling device of the dosing system ensures that the piezo stack extends in spite of the encapsulation, which can become very hot inside during operation. is cooled accordingly.
- the (uninterrupted) service life of the dosing system can also be significantly increased.
- a liquid or aqueous cooling medium can also advantageously be used for cooling, since thawing of the piezoelectrically active material due to the hermetically sealed encapsulation is prevented.
- the cooling device can be designed to generate the direct cooling of at least a portion of the piezo actuator and / or the movement mechanism coupled to the piezo actuator by means of a control and / or regulating unit as a function of at least one as a result of the operation To control and / or regulate the state parameters of the dosing system.
- This process is also known as thermal control.
- the metering system is preferably coupled to a control and / or regulating unit.
- a number of partial areas, which in total z. B. comprise the entire surface of the piezo actuator or the movement mechanism are combined in terms of control technology to form a unit and are regulated uniformly as a function of at least one state parameter.
- control is used below as a synonym for control and / or regulation. This means that even when a control is mentioned, the control can include at least one control process.
- a controlled variable (as the actual value) is generally recorded continuously and compared with a reference variable (as the setpoint).
- the control is usually carried out in such a way that the controlled variable is adjusted to the reference variable. This means that the controlled variable (actual value) continuously influences itself in the action path of the control loop.
- a state parameter e.g. B. a (surface) temperature in at least a partial area of the piezo actuator and / or a (surface) temperature in at least a partial area of the movement mechanism coupled to the piezo actuator and / or a temperature in at least a partial area of an outside of the housing (" Outside temperature ").
- the metering system can comprise one or more temperature sensors, which are preferably coupled to a control unit of the metering system. In order to monitor the temperature of the piezo actuator spatially (as high a resolution as possible), several temperature sensors can be implemented along a longitudinal extension on the actuator surface of the piezo actuator.
- a plurality of temperature sensors can also be arranged in different areas of an inner wall and / or outer wall of the actuator shell.
- a number of temperature sensors can also be arranged in direct contact with at least one component of the movement mechanism, e.g. B. the lever.
- a number of temperature sensors can be mounted in the immediate vicinity of a respective component on or in the housing in order to estimate or extrapolate the temperature of the component.
- the temperature sensors can also be designed to determine the temperature of an assigned sub-area of the movement mechanism or of the piezo actuator from a certain distance, eg. B. by means of infrared temperature sensors.
- a relevant state parameter, depending on which the control takes place can preferably correspond to an average temperature or a maximum temperature of a number of sub-areas of the piezo actuator and / or movement mechanism.
- Another state parameter can be a length of at least a partial area of the piezo actuator.
- piezo actuators or the individual piezo elements can have a temperature-dependent expansion behavior. Therefore, to monitor the (operating) state of the piezo actuator, at least one so-called strain gauge for monitoring an absolute length and / or a dynamic change in length of the piezo actuator can be attached to the actuator surface. By means of the strain gauge, both the longitudinal expansion of the entire actuator and a section thereof can be monitored.
- the strain gauge can also be provided in the interior of an actuator cover (e.g. in the area of an inner wall) and / or on an outside of the actuator cover.
- a distance between the ejection element, preferably a plunger tip, and the nozzle or a nozzle seat of the metering system when the metering system is open can be used as a status parameter for controlling the cooling.
- signs of wear can occur, particularly in the area of the plunger tip, which can cause the plunger to shorten.
- a thermally induced change in length of the actuator can also result in the fact that the actual position of the plunger tip deviates from a desired position due to the coupling with the movement mechanism.
- the metering system can have at least one motion sensor, e.g. B. include a magnetic sensor for measuring the distance of a movable component.
- At least one thermally compensated Hall sensor can preferably be arranged in a region of the housing in such a way that the sensor can interact with a magnet of the plunger and / or the lever in order to carry out a preferably vertical displacement measurement of the plunger or lever.
- a position of the plunger tip in the closed state of the metering system can preferably be compared with a position in the open state in order to determine the actual movement of the plunger or the plunger tip for dispensing the dosing agent.
- a further additional or alternative state parameter can be the quantity of dosing agent dispensed by the dosing system in a certain time interval.
- the piezo actuator can become very hot due to the work to be done, especially with high-frequency dispensing and / or with highly viscous media. Therefore, a flow rate of the medium, e.g. B. in the area of the feed channel, are taken into account as state parameters.
- a flow rate of the medium e.g. B. in the area of the feed channel
- At least one flow sensor can be arranged in an area of the feed channel.
- a “learned” (metering substance-specific) state parameter it is also possible for a “learned” (metering substance-specific) state parameter to be stored in the control unit or in the metering system.
- the control concept can therefore preferably also be used in metering systems in which the piezo actuator and / or the movement mechanism are used for “cooling purposes” with an uncooled cooling medium, for. B. compressed room air (ie no pre-cooled cooling medium in the sense of the invention), flows around.
- the “cooling” of at least a partial area of the piezo actuator and / or of the movement Mechanism ie the flow around or flow to a respective section for “cooling purposes”, depending on the length of at least a section of the piezo actuator and / or a distance between the ejection element and the nozzle of the dosing system and / or a dosing agent quantity .
- the aforementioned status parameters provide essential knowledge about the current (operating) status of the actuator unit and can therefore be used for corresponding compensation measures as part of a comprehensive temperature management of the metering system.
- a control in particular a regulation of the direct cooling of at least one partial area of the piezo actuator and / or movement mechanism can preferably take place in such a way that at least one state parameter in these partial areas requiring control is permanent during operation of the metering system, in particular also under load fluctuations of the piezo actuator , is kept stable in a non-critical area, d. H. corresponds to a predetermined target value.
- the setpoint is preferably not exceeded or undershot as a result of the regulation.
- the control can also be carried out in such a way that the status parameter is kept continuously in a desired range during operation.
- a corresponding setpoint or setpoint range can be assigned to the respective status parameter as the actual value.
- B. is stored in the control unit.
- a different setpoint can be assigned to one and the same state parameter in different areas of the actuator unit. For example, a temperature setpoint of the piezo actuator could be significantly higher than a temperature setpoint of the movement mechanism.
- the direct cooling of a number of subareas of the piezo actuator can preferably be regulated in such a way that a temperature of the actuator surface (as the desired value) during operation of the metering system constantly corresponds to an ambient temperature of the metering system. In this way, a “thermal constancy” of the piezo actuator can be achieved, whereby thermally induced longitudinal expansion of the piezo actuator is largely prevented during operation.
- the maximum permissible temperature (in operation) of the piezo actuator can be set as the setpoint value so that the highest possible dosing precision of the dosing system is achieved.
- the current and / or expected power conversion of the actuator can preferably be taken into account. Due to the poor thermal conductivity of the commonly used piezo material, it can in the event of strong fluctuations in the load of the piezo actuator, in particular in the case of an encapsulated piezo actuator, the heat loss generated in the interior of the piezo actuator or in the piezo stack is not conducted quickly enough to the outside to the cooled surface of the piezo actuator or the actuator shell.
- a temperature gradient can form from a core of the actuator or the piezo stack to its outer surfaces or to the actuator shell.
- the length of the piezo actuator or piezo stack can therefore change despite reaching a target temperature on the surface of the piezo actuator or the actuator shell.
- the respective power conversion of the piezo actuator can be taken into account, which z. B. is stored in the control unit in order to determine a “corrected” target temperature of the surface (of the piezo actuator or the actuator shell), which prevents a longitudinal expansion of the overall piezo actuator even in the event of dynamic load changes of the piezo actuator or the encapsulated piezo stack .
- the longitudinal expansion of the piezo actuator could also be directly taken into account as the desired value, which, as said, can be determined by means of strain sensors.
- the control in particular the thermal regulation of the cooling of a number of subareas of the piezo actuator, can preferably take place in such a way that the piezo actuator has a constant, predefinable piezo actuator length during operation of the metering system. Accordingly, an “output” length of the piezo actuator at room temperature or a maximum tolerable length of the piezo actuator could be used as the setpoint.
- the direct cooling of a number of sub-areas of the movement mechanism can be regulated (thermally) in such a way that as constant as possible a constant (constant) movement of the ejection element, in particular the tip thereof, is achieved during operation of the metering system.
- a distance between a plunger tip and a nozzle insert or a sealing seat of the nozzle when the metering system is open or a distance of the plunger tip per plunger stroke could serve as the setpoint or setpoint range. It is also conceivable that a maximum permissible “outside temperature” of the housing is used as the setpoint.
- an essentially “real-time comparison” of at least one status parameter with the assigned target value can take place in the control unit.
- a plurality of partial areas can preferably be regulated uniformly as a function of only one state parameter, at least one further state parameter being continuously “monitored” by the control unit at the same time.
- a “monitoring” is e.g. B. useful if a respective state parameter (currently) clear is below an assigned setpoint, so that regulation is not (yet) necessary in this regard.
- the actual value of the "monitored" state parameter approaches a setpoint, e.g. B. as a result of changed operating conditions of the actuator this state parameter for controlling the cooling could also be taken into account.
- the respective status parameters depending on which the direct cooling of a number of partial areas takes place, can preferably change during operation of the metering system.
- the intensity of the cooling can be regulated, for. B. by regulating a volume flow of the pre-cooled cooling medium flowing into the housing. Consequently, the strength with which the cooling medium is applied to a number of sub-areas can also be regulated.
- the (target) temperature of the pre-cooled cooling medium can also be regulated when it enters the housing.
- the control unit can be coupled to a refrigeration generating device.
- the intensity of the direct cooling can preferably be adapted dynamically (as required) during operation of the metering system.
- the exact "location" of the direct cooling can also be regulated.
- the piezo actuator and the movement mechanism can preferably be acted upon separately with cooling medium, as will be explained below.
- the cooling device of the metering system can be designed to jointly, that is, a number of sub-areas of the piezo actuator and the movement mechanism. H. as a unit, directly for cooling ("combined cooling").
- the cooling device preferably comprises only a single cooling circuit, each with a feed device or discharge device for cooling medium, the cooling circuit comprising the actuator chamber and the chamber of the movement mechanism together. This means that partial areas of the piezo actuator and the movement mechanism are acted upon by a cooling medium of the same (target) temperature.
- the direct cooling can preferably be controlled as a function of a state parameter of only one of the two components. For example, the direct cooling of the piezo actuator and the movement mechanism could only be regulated as a function of a surface temperature of the piezo actuator.
- the cooling device can also be designed to separately control and / or regulate the direct cooling of at least a portion of the piezo actuator by means of the control unit, in particular separates or independently of the control and / or regulation of the direct cooling of at least a portion of the movement mechanism coupled to the piezo actuator.
- the cooling device can therefore preferably have two separately designed cooling circuits to be operated independently, each with separate feed and discharge devices - Gen include which can be loaded individually with the pre-cooled cooling medium.
- the cooling circuit for cooling the piezo actuator can preferably be designed separately, in particular (spatially) separately from a cooling circuit for cooling the movement mechanism.
- control unit can also comprise two separate “cooling control or control circuits” in order to record and process the respective status parameters of the piezo actuator or the movement mechanism separately from one another, ie to supply the respective cooling circuits with cooling medium accordingly and that Guide the cooling medium to the respective areas to be cooled.
- a number of partial areas of the piezo actuator e.g. B. the entire actuator surface can be cooled by the cooling device to a first target temperature such that conditions which are as advantageous as possible for the operation of the actuator or the dosing accuracy is increased.
- a number of sub-areas of the movement mechanism e.g. B. a "head region" of the lever, which comes into contact with the plunger, can be cooled by means of the cooling device to a second target temperature, which can differ from the first target temperature.
- the separate cooling of these sub-areas makes it possible to decouple the cooling of the movement mechanism from the often very dynamic cooling requirements of the piezo actuator.
- the direct cooling of partial areas of the movement mechanism can preferably be regulated (thermally) in such a way that signs of wear and tear of components of the movement mechanism and / or ejection element can be compensated for.
- the movement mechanism can heat up, in particular due to frictional heat.
- the plunger can heat up due to contact with a preheated medium in the area of the plunger tip.
- the at least intermittent coupling of the two components can also influence one another thermally.
- a thermal expansion of the lever, in particular in a region of the “lever head”, and / or a plunger head of the plunger can preferably be used to compensate for a shortening of the plunger in the region of the nozzle due to wear, in order to compensate for the desired stroke of the To keep the tappet stable (as a status parameter).
- the plunger projects at least partially, in particular with the plunger head, into a chamber of the dosing system surrounding the movement mechanism, so that the plunger is “flowed through” by the cooling medium for cooling the movement mechanism.
- the movement mechanism can therefore preferably be cooled less intensively than the possibly highly heated piezo actuator, in order to use the (inherent) heat present in the lever and / or plunger to maintain the desired stroke of the plunger.
- the direct flow of the movement mechanism can be controlled in such a way that the desired stroke of the tappet is maintained in the event of “co-flow” of at least partial areas of the ejection element.
- the temperature management of the metering system can advantageously be used to ensure that the extent and the intensity of the cooling of the piezo actuator or movement mechanism are always adapted to the current (operating) state of the actuator unit.
- load fluctuations of the piezo actuator can be taken into account in order to correspondingly throttle the cooling output in times of lower load on the actuator unit and thus to reduce the consumption of cooling medium.
- Decoupling the cooling of the piezo actuator and the movement mechanism can lead to a further reduction in the cooling medium consumption. Furthermore, this also increases the scope for compensation measures against signs of wear of the movement mechanism, which can have an advantageous effect on the precision of the metering system.
- a metering system with “combined cooling” offers the advantage of simplifying the design of the cooling device and thus reducing the manufacturing costs of the metering system, since only one common cooling circuit is required for the entire actuator unit. This type of construction can also compensate for signs of wear, e.g. B. by selective heating of the movement mechanism, as will be explained later.
- the pre-cooled cooling medium which is supplied to the cooling circuit or circuits is preferably designed for this purpose, ie cold enough and present in the housing in a sufficient quantity in order to permanently maintain a predeterminable cooling capacity during operation of the metering system.
- the control unit can preferably (low) determine the (target) temperature of the cooling medium in such a way that a (respective) setpoint explained at the beginning in at least a partial area of the piezo actuator and / or the movement mechanism coupled to the piezo actuator during operation in succession direct cooling is kept stable.
- the cooling device can comprise a refrigeration device.
- the cooling device in particular the feed device, is preferably designed to provide the precooled cooling medium in the actuator chamber and / or the chamber of the movement mechanism in the housing.
- the cooling device is preferably also designed to distribute the precooled cooling medium in the housing as required.
- the pre-cooled cooling medium also has a certain (target) temperature when it hits the surface of a number of partial areas of the piezo actuator or of the movement mechanism.
- the cooling device can comprise flow-directing elements within the housing, eg. B. separately controllable flow channels, baffles, fans etc.
- the cooling device thus comprises at least components to cool a cooling medium to a (target) temperature, to provide the cooling medium in the housing with a (target) temperature, the cooling medium in the housing to lead into a number of sub-areas of the piezo actuator and / or the movement mechanism, to discharge the cooling medium from the housing and optionally to feed it again to the refrigeration device.
- the cooling device for cooling the cooling medium can preferably comprise any type of “active” cooling source.
- the cold source is preferably designed to actively heat energy from a substance, for. B. a cooling medium, to actively "generate" cold.
- the cooling device can therefore preferably comprise at least one cold source.
- the refrigeration device can be designed separately, that is, not as a fixed component of an individual metering system.
- the refrigeration device can preferably interact with a plurality of metering systems.
- the cooling device can be supplied by means of a cooling medium supply line to the cooling device, e.g. B. a temperature-insulated flexible line, can be coupled to at least one connection point of the housing.
- the refrigeration device is preferably designed to cool the cooling medium to a specific absolute (target) temperature.
- the refrigeration device can preferably be operated regardless of a temperature and / or humidity of the ambient air of the metering system or the refrigeration device. This means that the temperature of the cooling medium can not only be reduced relative to an ambient temperature by means of the refrigeration device, but can also be reduced to “any”, ie. H. value set with regard to the operation of the dosing system.
- the refrigeration device can preferably use the principle of a refrigeration machine (as a refrigeration source).
- the refrigeration device could include at least one compression refrigeration system.
- Such a refrigeration machine can preferably be designed to supply two or more separate metering systems with cooled cooling medium. Liquid and / or gaseous media are suitable as the cooling medium, cooling media with a high heat capacity being preferred.
- the refrigeration device could make use of the principle of thermoelectric cooling.
- the refrigeration device can therefore preferably comprise at least one Peltier element (as a refrigeration source).
- the refrigeration device can comprise at least one vortex tube (as a refrigeration source) for cooling the cooling medium to a specific (target) temperature.
- the temperature of the cooled air emerging from the vortex tube can preferably be regulated by means of an adjustable control valve in the region of a hot air outlet of the vortex tube.
- a volume flow of the air flowing into a swirl chamber of the swirl tube can also be adjusted in order to obtain a pre-cooled amount that is appropriate for the needs
- To provide cooling medium e.g. B. by means of a proportional valve upstream of the vortex tube.
- the control valve or the proportional valve of a respective vortex tube can preferably be controlled by means of the control unit in such a way that the cooling medium is provided in the housing with a (target) temperature.
- the amount of precooled cooling medium provided by a single swirl tube is preferably sufficient for direct cooling of the temperature-sensitive components of an actuator unit.
- the refrigeration device can particularly preferably be a refrigeration machine, e.g. B. include a compression refrigeration system, and at least one interacting, downstream vortex tube.
- the cooling device can therefore preferably also have more than one, ie. H. comprise at least two different cold sources.
- the plurality of cold sources can be designed to be separately controllable.
- a cooling medium which has already been preheated or cooled can preferably be finally cooled to a (target) temperature by means of the vortex tube. As a result of this interaction, the cooling medium can also be cooled to temperatures below a “lowest possible” cooling temperature of a refrigerator.
- the cooling device of the cooling device can advantageously be achieved by means of the cooling device of the cooling device that a sufficiently large amount of a sufficiently cooled cooling medium is always present in the housing in order to be able to keep one or more status parameters in a number of partial areas in the operation of the metering system permanently in an uncritical target area.
- a refrigeration machine interacts with a vortex tube
- a very wide or deep control range of the cooling can be achieved.
- the dosing system can also be used under unfavorable environmental conditions such as B. operate particularly high temperatures with a maximum dosing frequency, at the same time ensuring high dosing precision.
- At least a partial area of the movement mechanism of the actuator unit coupled to the piezo actuator can comprise a controllable heating device for heating at least a partial area of the movement mechanism.
- the heating device can be implemented as part of the movement mechanism, for. B. in the form of a heating coil in or on the lever.
- the housing of the actuator unit can comprise at least one heating device that can be regulated by means of the control unit for heating at least a partial area of the movement mechanism.
- the subarea can preferably be heated to a predeterminable temperature by means of conduction.
- the heater e.g. B. a heating cartridge or a heating coil can be thermally decoupled from the piezo actuator, for. B. by means of an insulating air-filled slot in the housing between the heater and the piezo actuator.
- the housing can preferably comprise at least one temperature sensor, in particular in an area between the heating cartridge and the thermal decoupling.
- a heating device can also be provided for heating the nozzle or the metering material in the nozzle area.
- the heating device is preferably designed, in cooperation with the cooling device of the metering system, to keep one or more state parameters of the metering system as constant as possible during operation in a number of partial areas of the piezo actuator and / or movement mechanism, preferably in the area of a respective setpoint .
- the heating device and the cooling device of the metering system can preferably cooperate in such a way that a (target) temperature in at least a partial area of the piezo actuator and / or the movement mechanism coupled to the piezo actuator and / or a length of the piezo actuator and / or a distance between the Ejection element and the nozzle in the open state of the metering system and / or a metering agent quantity during metering agent dispensing is predominantly constant in the operation of the metering system.
- the heating effect and the cooling effect can preferably be coordinated with one another by means of the control unit in such a way that at least one “control status parameter” is kept in a desired range in the most efficient manner during operation of the metering system.
- the control unit can preferably comprise a “heating control circuit” in order to control the heating device separately, in particular separately from the cooling device.
- the heating device and the cooling device can preferably be operated at least temporarily in parallel, ie a number of partial areas can be heated and cooled directly at the same time (“overlapping control”).
- the “overlapping control” is preferably carried out in such a way that the consumption of heating energy or cooling medium is as low as possible is, ie the heating device and the cooling device do not continuously work against each other at full load.
- the cooling device could be controlled in such a way that a target temperature is reached in an area of the actuator surface.
- the heating device can be controlled in such a way that a number of sub-areas of the movement mechanism (and by means of conduction also of the ejection element or plunger) are heated to a (higher) desired temperature in order to maintain a desired value of the stroke of the ejection element.
- the heating device can also be controlled in order to achieve a desired thermally induced expansion in a region of the housing, in particular in a region of the housing that encompasses the chamber of the movement mechanism.
- the thermally induced expansion of at least one area of the housing can preferably take place in such a way that a setpoint value of the stroke of the ejection element is kept stable during operation of the metering system.
- the possibility of wear compensation can be further improved by means of a separately controllable heating device.
- B. by a shortening of the ejection element or plunger is compensated for by targeted heating or controlled thermal expansion of individual sections of the movement mechanism or indirectly also of the plunger and / or the housing.
- the plunger tip can thus always be positioned at an initial or nominal distance from the nozzle when the dosing system is open, so that the quantity of dosing agent emitted per plunger stroke remains constant.
- the heating device is designed and arranged in the metering system in such a way that the relevant status parameters of the piezo actuator (eg the actuator temperature or length) can also be kept in a non-critical range.
- the advantages mentioned above can also be used in the “combined cooling” system, so that despite a direct application of a number of parts of the movement mechanism with a possibly very cold cooling medium, a desired thermal expansion of these areas is achieved can be.
- a constructive simplification of the dosing system a permanently high precision in the dispensing of the dosing agent can be achieved.
- the slight, controlled “working against one another” (“overlapping control”) of the heating device and cooling device can also advantageously contribute to an increased “rigidity” or constancy of a state parameter of the dosing system with respect to external interference.
- FIG. 1 shows a sectional view of a metering system according to an embodiment of the invention
- FIGS. 2 to 4 parts of metering systems shown in section in accordance with other embodiments of the invention.
- FIG. 5 shows parts of an actuator unit of a dosing system according to an embodiment of the invention, shown in section,
- FIG. 6 shows a sectional view of an encapsulated piezo actuator for a dosing system according to an embodiment of the invention
- Figure 7 is a schematic representation of a cooling device for a metering system according to an embodiment of the invention.
- the metering system 1 is shown here in the usual intended position or position, eg. B in the operation of the metering system 1.
- a nozzle 40 in the lower region of the metering system 1, so that the drops of the medium are ejected downward through the nozzle 40 in an ejection direction R.
- this information always refers to such a, usually usual position of the dosing system 1.
- this does not exclude that the dosing system 1 in special applications also in a different position can be used and the drops are ejected laterally, for example.
- pressure and precise construction as well as control of the entire ejection system this is also possible in principle.
- the essential components of the metering system 1 include an actuator unit 10 and a fluidic unit 30.
- the actuator unit 10 and the fluidic unit 30 are firmly connected to one another, for example by B. by means of a fixing screw 23.
- the respective assembly pen 10, 30 can also be implemented in the manner of plug-in coupling parts which can be coupled to one another to form a quick coupling. Then the actuator unit 10 and the fluidic unit 30 could be coupled to one another without tools, in order to form the dosing system 1.
- Actuator unit 10 essentially comprises all components which drive or move an ejection element 31, here a plunger 31, in nozzle 40.
- B. a piezo actuator 60 and a movement mechanism 14 to be able to actuate the ejection element 31 of the fluidic unit 30 and similar components, as will be explained below.
- the fluidic unit 30 comprises all other parts which are in direct contact with the medium, and also the elements which are necessary for the relevant ones in contact with the medium to assemble standing parts together or to hold them in position on the fluidic unit 30.
- the actuator unit 10 comprises an actuator unit housing block 11 with two internal chambers, namely on the one hand an actuator chamber 12 with a piezo actuator 60 located therein and on the other hand an action chamber 13 into which the movable ejection element 31, here the Ram 31, the fluidic unit 30 protrudes.
- the plunger 31 Via a movement mechanism 14, which protrudes from the actuator chamber 12 into the action chamber 13, the plunger 31 is actuated by means of the piezo actuator 60 such that the fluid to be dosed is ejected by the fluidic unit 30 in the desired amount at the desired time.
- the plunger 31 closes a nozzle opening 41 and thus also serves as a closure element 31. However, since most of the medium is only ejected from the nozzle opening 41 when the plunger 31 moves in the closing direction, it is used here as an ejection element 31 - draws.
- control the piezo actuator 60 it is electrically or signal-technically connected to a control unit 90 of the metering system 1.
- the connection to this control unit 90 is made via control cables 91, which are connected to suitable piezo actuator control connections 66, e.g. B. suitable plugs are connected.
- the two control connections 66 are each coupled to a contact pin 61 or to a respective connection pole of the piezo actuator 60 in order to control the piezo actuator 60 by means of the control unit 90.
- the control connections 66 can be guided through the housing 11 in a sealed manner such that essentially no air can penetrate from the outside into the actuator chamber 12 in the area of the respective implemented control connections 66, e.g. B.
- the piezo actuator 60 in particular the piezo actuator control connections 66, can, for. B. can be provided with a suitable memory unit (eg an EEPROM or the like) in which information such as an article name etc. or control parameters for the piezo actuator 60 are stored, which can then be read out by the control unit 90 in order to determine the Identify piezo actuator 60 and control it in the appropriate manner.
- Control cables 91 may include multiple control lines and data lines. However, since the basic control of piezo actuators is known, this will not be discussed further.
- the piezo actuator 60 can expand (expand) and contract again in the longitudinal direction of the actuator chamber 12 in accordance with a connection by means of the control device 90.
- the piezo actuator 60 can be inserted into the actuator chamber 12 from above.
- a spherical cap which can be adjusted in height by a screwing movement (not shown here) can then serve as the upper abutment, wherein a precise adjustment of the piezo actuator 60 to a movement mechanism 14, here a lever 16, is made possible.
- the piezo actuator 60 is mounted on the lever 16 downward via a pressure piece 20 tapering at an acute angle, which in turn rests on a lever bearing 18 at the lower end of the actuator chamber 12.
- the lever 16 can be tilted about a tilt axis K via this lever bearing 18, so that a lever arm of the lever 16 projects through an opening 15 into the action chamber 13.
- the lever arm has a contact surface 17 which points in the direction of the plunger 31 of the fluidic unit 30 coupled to the actuator unit 10 and which presses on a contact surface 34 of a plunger head 33.
- the contact surface 17 of the lever 16 is permanently in contact with the contact surface 34 of the plunger head 33, in that a plunger spring 35 presses the plunger head 33 against the lever 16 from below.
- the lever 16 rests on the plunger 31.
- the plunger spring 35 it would also be possible for the plunger spring 35 to be at a distance between the plunger 31 and the lever 16 in an initial or rest position, so that the lever 16 initially swings down drives freely through a certain section of the route and absorbs and then hits the plunger 31 or its contact surface 34 with a high pulse in order to increase the ejection pulse which the plunger 31 in turn exerts on the medium.
- the lever 16 at the end at which it comes into contact with the plunger 31, is pushed upwards by an actuator spring 19.
- the fluidic unit 30 is here by means of a fixing screw 23 with an actuator unit
- the tappet 31 is supported by means of the tappet spring 35 on a tappet bearing 37, to which a tappet seal 36 adjoins at the bottom.
- the tappet spring 35 pushes the tappet head 33 away from the tappet bearing 37 in the axial direction upwards.
- a plunger tip 32 is thus also pressed away from a sealing seat 43 of the nozzle 40. That is, Without external pressure from above on the contact surface 34 of the plunger head 33, in the idle position of the plunger spring 35, the plunger tip 32 is at a distance from the sealing seat 43 of the nozzle 40.
- a nozzle opening 41 is also free or unlocked.
- the dosing agent is fed to the nozzle 40 via a nozzle chamber 42 to which a feed channel 44 leads.
- the feed channel 44 is connected to a medium reservoir 46 by means of a reservoir interface 45.
- the fluid unit 30 can also comprise a number of additional components which are usually used in metering systems of this type, such as, for example, B. a frame part 47, a heating device 48 with heating connection cables 49 etc., to name just a few. Since the basic structure of metering systems is known, for the sake of clarity, components which relate to the invention at least indirectly are predominantly shown here.
- the metering system 1 comprises a cooling device 2 with a feed device 21 in order to feed a precooled cooling medium to the housing 11 of the actuator unit 10.
- the feed device 21 here comprises a plug nipple 21 or a hose olive 21 as a coupling point for connecting a cooling medium supply line (not shown).
- a cooling medium supply line not shown.
- the feed device 21 further comprises an inflow channel 26 adjoining the plug nipple 21.
- the inflowing cooling medium is directed inside the actuator chamber 12 by means of flow-directing elements (not shown here) to a number of partial areas of the piezo actuator 60, so that preferably the entire surface of the piezo actuator 60 is blown directly with the cooling medium.
- the actuator chamber 12 is continuously connected to the action chamber 13.
- the cooling medium flowing into the actuator chamber 12 e.g. B. compressed and cooled to a target temperature, directed by the cooling device so that a number of sub-areas of the movement mechanism is cooled directly.
- the cooling device is designed to form a cooling medium flow within the actuator chamber 12 and the action chamber 13 and to direct it in such a way that predominantly only the surfaces of parts to be cooled are focused, preferably frontally, with the cooling medium.
- other areas of the metering system 1 that are not to be cooled directly for. B. an outer wall of the housing 11 or an inner wall of the actuator chamber 12 or the action chamber 13, not blown in a focused manner with the cooling medium. The latter areas are passed or streaked by the cooling medium (“co-flowed”), but not directly flowed against, so that the cooling medium does not develop its full cooling capacity here.
- the cooling medium leaves the housing by means of a discharge duct 27 of a discharge device 22.
- the discharge device 22 is designed here as part of the cooling device 2 according to the invention.
- Mechanical abrasion from the actuator chamber 12 or action chamber 13 can preferably also be removed from the metering system 1 by means of the cooling medium flow.
- a number of sub-areas of the piezo actuator and the movement mechanism are combined, i. H. as one unit, directly cooled ("combined cooling"). Accordingly, the metering system 1 here only comprises one cooling circuit.
- the piezo actuator 60 and the movement mechanism 14 can be cooled directly with a constant intensity during operation of the metering system (“uncontrolled cooling”).
- the direct cooling by means of the control unit 90 is regulated as required. Since the piezo actuator 60 and the motion supply mechanism 14 are cooled here together or as a unit, the control unit 90 only requires a single control and / or regulating circuit.
- the cooling could be regulated as a function of a temperature of the actuator surface (as a status parameter) in order to regulate the piezo actuator 60 to a constant length during operation.
- the piezo actuator 60 can comprise a number of temperature sensors, the corresponding measured values being supplied to the control unit 90 by means of temperature sensor connection cables. This will be explained later with reference to FIGS. 3 and 6.
- the control unit 90 is equipped with a refrigeration device, e.g. B. a compression refrigeration system and / or a vortex tube (see FIG. 7), and controls them in dependence on the state parameter in such a way that a sufficiently cooled cooling medium with such a volume flow is supplied to the housing 11 and distributed in the housing 11 in such a way that the at least one status parameter as a result of the direct cooling corresponds permanently to an assigned setpoint.
- a refrigeration device e.g. B. a compression refrigeration system and / or a vortex tube (see FIG. 7)
- the housing 11 comprises a heating device 51, here a heating cartridge 51, which can be controlled by the control unit 90 by means of heating cartridge connection cables 92.
- the heat generated by the heating cartridge 51 leads z. B.
- a temperature sensor 52 is arranged in the housing 11 in the immediate vicinity of the heating cartridge 51 and is coupled to the control unit 90 by means of temperature sensor connection cables 86.
- the data determined by the temperature sensor 52 can be used to detect a temperature in a region of the housing 11.
- the control unit 90 can control the heating cartridge 51 in such a way that the housing 11, in particular an area of the housing 11 comprising the action chamber 13, is heated to a desired temperature despite the direct cooling of the movement mechanism 14 with the cooling medium (“overlapping Control ”) to achieve a desired thermal expansion of the housing 11.
- the thermal expansion can e.g. B. cause a length of the housing 1 1, which here corresponds to the vertical extension of the housing 1 1, increases by a desired amount.
- a position of the movement mechanism 14 relative to the piezo actuator 60 can also be changed (relatively). This changes the position of the lever 16 in relation to the ejection element 31, since the distance of the lever bearing 18 to the piezo actuator 60 is also influenced thereby, and in turn the distance between the ejection element 31 and the nozzle 40 of the metering system 1.
- a motion sensor 53 for example, a thermally compensated Hall sensor 53 is arranged, which interacts with a magnet in the area of the “lever head” (not shown), by a predominantly vertical movement of the “lever head” here as a result of a deflection of the piezo actuator 60 to determine.
- the vertical movement of the “lever head” essentially corresponds to a (vertical) stroke of the plunger 31.
- the data from the Hall sensor 53 distance measurement per plunger stroke
- conclusions can be drawn about the actual distance between the plunger tip 32 and the nozzle 40 or nozzle seat 43 when the metering system is in the open state (as a state parameter).
- the control unit 90 can e.g. B. taking into account the data of the temperature sensor 52 and the Hall sensor 53, control the heating cartridge 51 so that a desired stroke of the plunger 31 despite wear of the components of the movement mechanism 14 and / or the plunger 31 even during the direct cooling of the movement mechanism 14 is kept stable.
- the housing 11 comprises a vertically running air-filled slot 50 in order to thermally decouple the heating cartridge 51 from the piezo actuator 60 to be cooled.
- the heat generated by the heating cartridge 51 is thus predominantly directed in the direction of the movement mechanism 14.
- thermal decoupling of the actuator chamber 12 from the action chamber 13 can also be provided (FIG. 2).
- FIG. 2 shows parts of a metering system according to another embodiment of the invention.
- the fluidic unit corresponds here and in FIGS. 3 and 4 to that Structure according to the fluidic unit of Figure 1, so that this assembly is only partially shown below for clarity.
- the control unit and the corresponding cables for contacting the piezo actuator or the heating cartridge and the temperature sensor in the housing are also not shown in the following, or only partially, in order to save repetition.
- the cooling device 2 of the metering system 1 here comprises two separately designed and controllable cooling circuits in order to cool the piezo actuator 60 independently or separately from the movement mechanism 14.
- a first cooling circuit of the cooling device 2 is designed to cool the piezo actuator 60 directly, the cooling circuit comprising a feed device 21 with an inflow channel 26 and a cooperating discharge device 25 with an outflow channel 27 in the lower region of the actuator chamber 12.
- At least one O-ring 54 is located between a foot region of the piezo actuator 60, e.g. B. a circular plate on which the piezo actuator 60 is attached, and an inner wall of the actuator chamber 12.
- the O-ring 54 thus limits the actuator chamber 12 towards the bottom and forms a barrier for the cooling medium.
- the O-ring 54 is part of the cooling device 2. Because of the subdivision, a chamber is formed below the O-ring 54 in the region of the lever bearing 18, which chamber is no longer included in the cooling circuit of the actuator chamber 12. This chamber is connected to the action chamber 13 by means of the opening 15 and is therefore regarded in this embodiment as part of the action chamber 13, that is to say as a chamber 13 surrounding a movement mechanism 14 of the metering system 1.
- the cooling device 2 here comprises a second, separate cooling circuit for the direct cooling of at least a partial area of the movement mechanism 14.
- the (expanded) action chamber 13 has its own supply device 24 with an inflow channel 26 for a pre-cooled cooling medium and a discharge device 22 interacting therewith with one Outflow channel 27.
- the cooling device 2 can be controlled by means of the control unit (not shown here) in such a way that the two cooling circuits are supplied separately with cooling medium by means of the independently designed supply device 21 or 24.
- the current volume flow and the respective temperature of the supplied cooling medium are adapted to a particular situation of the piezo actuator 60 or of the movement mechanism 14 as required.
- a less intensive cooling of the movement mechanism 14 can lead to the friction heat of the movement mechanism 14 being generated alone being sufficient for wear compensation.
- the housing 11 here further comprises a horizontal air-filled slot 50 in order to thermally decouple the piezo actuator 60, which is typically cooled more than the movement mechanism 14, from the movement mechanism 14. Unwanted thermal interactions between the two cooling circuits can thus be reduced.
- FIG. 3 shows a further embodiment of a metering system which essentially corresponds to that of FIG. 1 with regard to the cooling device.
- the piezo actuator here comprises an actuator housing 62, in which a piezo stack is hermetically sealed.
- the piezo actuator or the piezo stack is connected here by means of the two outer contact pins 61 (see also FIG. 6).
- the two contact pins 61 shown here in the middle are used to transmit the measured values of a number of temperature sensors of the piezo actuator or the piezo stack from the actuator sleeve 62 to the control unit (not shown).
- the contact pins 61 are each connected to the control unit on the one hand by means of temperature sensor connection cables 86 and on the other hand in the actuator sleeve 62 to one or more temperature sensors (not shown).
- FIG. 4 essentially corresponds to the metering system from FIG. 2.
- a piezo stack encapsulated in an actuator sleeve 62 is also arranged in the actuator chamber 12.
- cooling medium is directly applied to a number of partial areas of a surface or to the outside of the actuator sleeve 62 facing the actuator chamber 62 by means of a first cooling circuit of the cooling device 2.
- the precooled cooling medium can be applied to at least a portion of the movement mechanism 14 by means of a second cooling circuit of the cooling device 2.
- FIG. 5 shows in detail a part of an actuator unit with an encapsulated piezo actuator for a metering system according to an embodiment of the invention.
- the actuator sleeve 62 with the piezo stack encapsulated therein is arranged in the actuator chamber 12 in such a way that the actuator envelope 62, at least in the region of bulges 82, borders directly on an inner side 80 of the wall 79 of the actuator chamber 12. Between the respective bulges 82 of the actuator sleeve 62 there are periodically substantially horizontally extending indentations
- the cooling device 2 here comprises a cooling medium supply line 84, which is coupled to a pump 28 of a supply device 21.
- the coolant supply line could be any suitable coolant supply line.
- the pump 28 can also be coupled to an adjustable cooling air supply (not shown) of the feed device 21.
- the pump 28 can be controlled by the control unit 90 by means of a control connection 29.
- the pump 28 In order to supply the cooling medium to the actuator chamber 12, the pump 28 is connected to an inflow channel 26 for the cooling medium by means of the feed device 21.
- the inflow channel 26 of the cooling device 2 runs here directly along an outer side 81 of the chamber wall 79, ie. H. the inflow channel 26 is delimited by the outside 81 of the chamber wall 79 and the housing 11.
- the inflow channel 26 has a number of openings 88 or openings 88 in the chamber wall 79 along the actuator chamber 12. A respective opening 88 thus represents a connection between the inflow channel 26 and the actuator chamber 12.
- the latter is positioned in the actuator chamber 12 in such a way that an opening 88 between the inflow channel 26 and the actuator chamber 12 and a cooperating opening 88 '(shown here on the left) between the actuator chamber 12 and an outflow channel 27 in a horizontal plane with a single groove 83 of the actuator sleeve 62 are arranged.
- the gaseous and / or liquid cooling medium flowing through a respective opening 88 from the inflow channel 26 into the actuator chamber 12 is guided along a respective channel 83, which is vertically delimited by the adjacent bulges 82, essentially horizontally along the actuator sleeve 62 and finally arrives into the outflow channel 27 or by means of the discharge device 25 into a cooling medium discharge line 85 of the cooling device 2.
- a number of partial areas of the actuator casing 62 are thus cooled directly.
- a heat-conducting medium can be arranged in the actuator sleeve 62, as will be explained with reference to FIG. 6.
- the piezoelectrically active material 67 that is to say the piezo stack 67, is arranged between a cover 64 and a bottom 63 of the actuator casing 62 and is laterally surrounded by a fold-like casing 74.
- the jacket 74 is firmly connected to the cover 64 and the bottom 63 in order to hermetically seal the piezo stack 67 from its surroundings.
- the cover 64 comprises four glass leadthroughs 65 (only one shown here), by means of which a contact pin 61 is hermetically sealed and electrically insulated from the interior of the actuator cover 62 to the outside of the actuator cover 62.
- a contact pin 61 is connected to an outer electrode 70 of the piezo stack 67, for. B. soldered.
- a total of two outer electrodes 70 run on two opposite sides of the piezo stack 67 along its longitudinal extent between the two inactive head or foot areas 73 on the outside or surface 77 of the piezo stack 67.
- Four temperature sensors 78 are arranged in the actuator sleeve 62; three of them on the surface 77 of the piezo stack 67 along the longitudinal extent of the piezo stack 67 and another in measurement contact with the jacket 74 or the inner wall 74 of the actuator sleeve 62.
- a respective temperature sensor 78 with two contact pins 61 each can be connected in order to generate measured values or to transmit them to the control unit.
- the individual sensor signals can also be placed on only one contact pin 61 and modulated in a suitable manner, provided the temperature sensors 78 are bus-compatible IC temperature sensors.
- a strain gauge 87 is also arranged in the actuator sleeve 62 on the surface 77 of the piezo stack 67. The strain gauge 87 extends here essentially along the entire longitudinal extent of the encapsulated piezo stack 67, that is to say between an inactive foot or head region 73.
- the corresponding measured values (state parameters) of the strain gauge 87 can be transmitted to the control unit of the metering system by means of contact pins 61 (Not shown).
- a further strain gauge 87 is arranged on the outside of the actuator sleeve 62, the strain gauge 87 extending there between the bottom 63 and the cover 64 and thus being able to detect an overall deflection, in particular also a change in length, due to the temperature, of the encapsulated piezo stack 67.
- the actuator sleeve 62 comprises a liquid and / or solid filling medium 75 which efficiently dissipates the heat generated during operation from the surface 77 and transfers it to a region of the actuator sleeve 62 which is free from direct cooling is included by means of the cooling device.
- the filling medium can also comprise a moisture-suppressing medium.
- the actuator sleeve 62 further comprises an expansion area 76, e.g. B. a gas bubble 76 or a gas-filled region 76.
- FIG. 7 schematically shows the structure of a cooling device 2 according to an embodiment of the metering system for the direct cooling of a number of partial areas of the piezo actuator or of the movement mechanism.
- the control unit 90 controls a refrigeration device 55 of the cooling device 2, e.g. B. a compression refrigerator 55, depending on at least one state parameter of the metering system 1 so that the cooling medium is cooled to a certain (first) temperature.
- the cooling medium e.g. B. compressed room air
- the refrigerator 55 is supplied by means of a coolant supply KMZ.
- the cooling medium emerging from the cooling machine 55 has already been cooled to a temperature below the ambient temperature of the metering system 1 and reaches a downstream vortex tube 57 of the cooling device 2 by means of suitable insulated lines.
- the vortex tube 57 comprises a controllable control valve 94 in the area of a hot air outlet HAW of the vortex tube 57. Both the temperature and the valve 94 can be controlled by means of the valve 94 the (volume) flow of the cooled cooling medium ("cold air portion") can be regulated. Basically, opening the valve leads to a reduction in the current and also in the temperature of the cooled air emerging from the vortex tube 57. The cooled cooling medium leaves the vortex tube 57 at a cold air outlet of the vortex tube 57 in one direction SKM.
- a "hot air portion" of the vortex tube is led away from the vortex tube 57 or dosing system 1 by means of the hot air outlet HAW.
- a proportional valve 56 can be connected upstream of the vortex tube 57, which can be controlled by means of the control unit 90.
- the cooling medium is fed into the housing 11 of the metering system by means of a cooling medium supply line 84, which is coupled on the one hand to the vortex tube 57 and on the other hand to a feed device 21. Tems 1 introduced to cool a number of sub-areas of the piezo actuator and the movement mechanism together ("combined cooling).
- a controllable pressure reducer 59 is provided here between the vortex tube 57 and the feed device 21.
- the actuators described, the controllable compression refrigerator 55, the proportional valve 56, the pressure reducer 59 and the controllable control valve 94 can be used individually or in addition.
- the arrangement of the basic cooling circuit shown thus shows an almost maximum expansion stage in order to describe the function of the individual components.
- a first vortex tube 57 can be provided for cooling the piezo actuator as needed and a second vortex tube 57 for cooling the movement mechanism as needed.
- the cooling medium is guided through the housing 11 by means of the cooling device 2 in such a way that a number of partial areas of the piezo actuator and the movement mechanism are cooled directly.
- the cooling medium which may have warmed up as a result of the heat dissipation from the piezo actuator or movement mechanism, is removed from the housing 11 by means of at least one discharge device 22 or a cooling medium discharge line 85 or in the area of a hot air outlet HAD of of the actuator unit 10.
- a further pressure reducer 59 is arranged here in the area of the hot air outlet HAD.
- the pressure reducers 59 are shown here as optional components of the cooling device 2.
- the proportional valve 56 is already designed to set the pressure in the cooling medium supply line 84 or in the cooling circuit via the possible flow through the vortex tube 57, eg. B. to reduce.
- the flow of cooling medium through the vortex tube 57 and the division into a hot air part and a cold air part also lead to a reduction in pressure.
- the housing 11 comprises a heating cartridge 51, which can be controlled by means of the control unit 90 such that at least a portion of the movement mechanism is heated to a (target) temperature. Furthermore, a number of temperature sensors 78, 52 are arranged in the actuator unit 10 in order to determine a temperature of at least one partial area to detect the piezo actuator or the movement mechanism. The corresponding data are supplied to the control unit 90 as status parameters of the metering system.
- control unit 90 can calculate or carry out a temperature management of the dosing system in order to achieve a high, as constant as possible dosing precision.
- control unit 90 can control the individual components of the cooling device 2, that is to say the cooling machine 55, the proportional valve 56, the vortex tube 57 or the control valve 94, the pressure reducer 59, the heating cartridge 51 and, if appropriate, further components with corresponding ones Apply control signals.
- HAD hot air outlet dosing system HAW hot air outlet swirl tube K tilting axis
Landscapes
- Reciprocating Pumps (AREA)
- Coating Apparatus (AREA)
- Fuel-Injection Apparatus (AREA)
- Micromachines (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020217008205A KR20210068410A (ko) | 2018-10-05 | 2019-09-24 | 냉각 장치를 갖는 도징 시스템 |
JP2021515577A JP2022501184A (ja) | 2018-10-05 | 2019-09-24 | 冷却装置を備える投与システム |
US17/278,608 US11498092B2 (en) | 2018-10-05 | 2019-09-24 | Dosing system with a cooling device |
CN201980062163.3A CN112770845B (zh) | 2018-10-05 | 2019-09-24 | 具有冷却装置的计量系统 |
EP19782925.2A EP3860771A1 (de) | 2018-10-05 | 2019-09-24 | Dosiersystem mit kühleinrichtung |
SG11202102551QA SG11202102551QA (en) | 2018-10-05 | 2019-09-24 | Dosing system with a cooling device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102018124662.5A DE102018124662A1 (de) | 2018-10-05 | 2018-10-05 | Dosiersystem mit Kühleinrichtung |
DE102018124662.5 | 2018-10-05 |
Publications (1)
Publication Number | Publication Date |
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WO2020069909A1 true WO2020069909A1 (de) | 2020-04-09 |
Family
ID=68138024
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2019/075644 WO2020069909A1 (de) | 2018-10-05 | 2019-09-24 | Dosiersystem mit kühleinrichtung |
Country Status (8)
Country | Link |
---|---|
US (1) | US11498092B2 (de) |
EP (1) | EP3860771A1 (de) |
JP (1) | JP2022501184A (de) |
KR (1) | KR20210068410A (de) |
CN (1) | CN112770845B (de) |
DE (1) | DE102018124662A1 (de) |
SG (1) | SG11202102551QA (de) |
WO (1) | WO2020069909A1 (de) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11384860B2 (en) * | 2017-05-08 | 2022-07-12 | Changzhou Mingseal Robot Technology Co., Ltd. | Fluid micro-injection device and flow channel assembly thereof |
BE1026401B1 (fr) * | 2018-06-20 | 2020-01-30 | Fast Eng Sprl | Dispositif pour la regulation de la temperature dans une enceinte |
WO2021019304A1 (en) * | 2019-07-30 | 2021-02-04 | Voyager Products Inc. | System and method for dispensing liquids |
Citations (5)
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KR101150139B1 (ko) * | 2012-01-12 | 2012-06-08 | 이구환 | 냉각수단이 구비된 디스펜서 |
US20150300748A1 (en) * | 2013-08-14 | 2015-10-22 | Protec Co., Ltd. | Temperature-sensing piezoelectric dispenser |
US20160136661A1 (en) * | 2014-11-18 | 2016-05-19 | Protec Co., Ltd | Piezoelectric dispenser and method of calibrating stroke of the same |
US20160339470A1 (en) * | 2015-05-22 | 2016-11-24 | Nordson Corporation | Piezoelectric jetting system with quick release jetting valve |
WO2017213920A1 (en) * | 2016-06-08 | 2017-12-14 | Nordson Corporation | Controlled temperature jetting |
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US20060188645A1 (en) * | 2005-02-18 | 2006-08-24 | Forti Michael S | Deposition device having a thermal control system |
DE102012104963A1 (de) * | 2012-06-08 | 2013-12-12 | Windmöller & Hölscher Kg | Vorrichtung zum Kühlen einer Folie mit einem Hebelsystem |
DE102012109124A1 (de) * | 2012-09-27 | 2014-03-27 | Vermes Microdispensing GmbH | Dosiersystem, Dosierverfahren und Herstellungsverfahren |
DE102013102693A1 (de) | 2013-03-15 | 2014-09-18 | Vermes Microdispensing GmbH | Dosierventil und Dosierverfahren |
DE102014205343A1 (de) * | 2014-03-21 | 2015-09-24 | Siemens Aktiengesellschaft | Kühlvorrichtung für eine Spritzdüse bzw. Spritzdüsenanordnung mit einer Kühlvorrichtung für das thermische Spritzen |
US11141755B2 (en) * | 2015-05-22 | 2021-10-12 | Nordson Corporation | Piezoelectric jetting system and method with amplification mechanism |
DE102016014943A1 (de) * | 2016-12-14 | 2018-06-14 | Dürr Systems Ag | Druckkopf mit Temperiereinrichtung |
-
2018
- 2018-10-05 DE DE102018124662.5A patent/DE102018124662A1/de active Pending
-
2019
- 2019-09-24 JP JP2021515577A patent/JP2022501184A/ja not_active Withdrawn
- 2019-09-24 CN CN201980062163.3A patent/CN112770845B/zh active Active
- 2019-09-24 US US17/278,608 patent/US11498092B2/en active Active
- 2019-09-24 EP EP19782925.2A patent/EP3860771A1/de active Pending
- 2019-09-24 SG SG11202102551QA patent/SG11202102551QA/en unknown
- 2019-09-24 KR KR1020217008205A patent/KR20210068410A/ko not_active Application Discontinuation
- 2019-09-24 WO PCT/EP2019/075644 patent/WO2020069909A1/de active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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KR101150139B1 (ko) * | 2012-01-12 | 2012-06-08 | 이구환 | 냉각수단이 구비된 디스펜서 |
US20150300748A1 (en) * | 2013-08-14 | 2015-10-22 | Protec Co., Ltd. | Temperature-sensing piezoelectric dispenser |
US20160136661A1 (en) * | 2014-11-18 | 2016-05-19 | Protec Co., Ltd | Piezoelectric dispenser and method of calibrating stroke of the same |
US20160339470A1 (en) * | 2015-05-22 | 2016-11-24 | Nordson Corporation | Piezoelectric jetting system with quick release jetting valve |
WO2017213920A1 (en) * | 2016-06-08 | 2017-12-14 | Nordson Corporation | Controlled temperature jetting |
Also Published As
Publication number | Publication date |
---|---|
DE102018124662A1 (de) | 2020-04-09 |
US11498092B2 (en) | 2022-11-15 |
JP2022501184A (ja) | 2022-01-06 |
US20210354168A1 (en) | 2021-11-18 |
EP3860771A1 (de) | 2021-08-11 |
CN112770845A (zh) | 2021-05-07 |
CN112770845B (zh) | 2023-08-08 |
KR20210068410A (ko) | 2021-06-09 |
SG11202102551QA (en) | 2021-04-29 |
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