Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
  • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium
  • F24H1/14—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
  • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium
  • F24H1/14—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form
  • F24H1/142—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form using electric energy supply
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J31/00—Apparatus for making beverages
  • A47J31/44—Parts or details or accessories of beverage-making apparatus
  • A47J31/54—Water boiling vessels in beverage making machines
  • A47J31/542—Continuous-flow heaters
  • A47J31/545—Control or safety devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H15/00—Control of fluid heaters
  • F24H15/20—Control of fluid heaters characterised by control inputs
  • F24H15/212—Temperature of the water
  • F24H15/219—Temperature of the water after heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/0005—Details for water heaters
  • F24H9/001—Guiding means
  • F24H9/0015—Guiding means in water channels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/20—Arrangement or mounting of control or safety devices
  • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
  • F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
  • F24H9/2028—Continuous-flow heaters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
  • G01K1/14—Supports; Fastening devices; Arrangements for mounting thermometers in particular locations
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K13/00—Thermometers specially adapted for specific purposes
  • G01K13/02—Thermometers specially adapted for specific purposes for measuring temperature of moving fluids or granular materials capable of flow

Definitions

• the present invention relates to a device for heating liquid, comprising a flow through heater having a conduit for conveying liquid and means for heating the liquid while flowing through the conduit; and means for detecting a temperature of liquid at an outlet of the flow through heater, which are part of a device for controlling a temperature of liquid at the outlet of the flow through heater.
• the present invention relates to a method for increasing accuracy in controlling a temperature of liquid at an outlet of a flow through heater.
• a quantity of water is heated before being made to flow through a quantity of ground coffee beans.
• a boiler i.e. a device having a container for containing a quantity of liquid, and heating means which are associated with the container, and which serve for heating liquid that is present inside the container. As soon as the temperature of the liquid is at a desired level, the liquid may be drawn from the boiler and used for its intended purpose.
• a flow through heater i.e. a device having a conduit for conveying liquid and means for heating the liquid while flowing through the conduit.
• electric heating elements are arranged around the liquid conveying conduit.
• the object is achieved by providing an insert which is partially inserted in the liquid conveying conduit of the flow through heater, at an outlet side of the flow through heater, wherein a portion of the insert that is located inside the liquid conveying conduit of the flow through heater is occupying at least a substantial portion of space which is present in a portion of the liquid conveying conduit which is not directly associated with the heating means of the flow through heater.
• the difficulties in controlling the outlet temperature are caused by a delay in the feedback process, which is related to the usual design of the flow through heater.
• the liquid conveying conduit and the heating elements are arranged with respect to each other in such a way that the conduit is protruding over some length with respect to the heating elements, at both an inlet side and an outlet side of the flow through heater.
• this phenomenon will be referred to as the presence of dead volume in the flow through heater, and the portion of the conduit which is not directly associated with heating elements is referred to as ineffective portion of the flow through heater.
• the dead volume and the associated delay time it is noted that the larger the dead volume, the harder it is to realize a desired average outlet temperature under all circumstances. This is especially apparent when the dead volume is significant when compared to a total volume of the flow through heater, which is the case in flow through heaters which are suitable to be used in espresso devices, for example.
• the longer the delay time the slower the response of a feedback control loop, and the earlier an occurrence of instability. Therefore, a longer delay time leads to a restriction of the applicability of the flow through heater. For example, an application in an espresso device is practically not possible, as such an application requires a fast responding feedback control loop.
• the present invention provides such solution by proposing the application of an insert which is partially inserted in the liquid conveying conduit of the flow through heater, at an outlet side of the flow through heater, wherein a portion of the insert that is located inside the liquid conveying conduit of the flow through heater is occupying at least a substantial portion of the dead volume.
• the delay time in detecting the outlet temperature of liquid is significantly reduced, as an advantageous result of which controlling the outlet temperature can be performed more effectively and accurately. According to the present invention, it does not take a modification of the design of the flow through heater, nor does it take an upgrade of the components used in the temperature controlling process to achieve such an advantageous result, but it only takes the application of a simple additional component, namely the insert.
• the insert comprises a duct system for conveying liquid from the liquid conveying conduit of the flow through heater to an outlet of the insert.
• the duct(s) of the liquid conveying duct system of the insert serve for transporting the liquid through the ineffective portion of the flow through heater.
• a diameter of the duct(s) of such a liquid conveying duct system is significantly smaller than a diameter of the liquid conveying conduit of the flow through heater at the outlet of the flow through heater, so that the volume of the duct(s) is much smaller than the volume of the ineffective portion of the flow through heater, and the dead volume reducing effect of the application of the insert may be optimal.
• the insert according to the invention may comprise a duct which is extending from an outer surface of the insert to the liquid conveying duct system, in a portion of the insert that is located outside of the liquid conveying conduit of the flow through heater, wherein the means for detecting a temperature of liquid at the outlet of the flow through heater are associated with this duct.
• this duct is located as close as possible to the end of the liquid conveying duct of the flow through heater, so that the detection of the outlet temperature may take place at a location which is as close as possible to the end of the liquid conveying duct, and the length over which a dead volume exists, albeit a relatively small dead volume, is kept to a minimum.
• this duct system may comprise at least two ducts which are oriented at an angle with respect to each other.
• the duct system comprises at least one duct for letting in liquid to the duct system, wherein this at least one inlet duct is oriented substantially perpendicular to a flow direction of liquid in the flow through heater, and is extending from one side of the insert to another; and a duct for letting out liquid from the duct system, wherein this outlet duct is oriented substantially parallel to the flow direction of liquid in the flow through heater, and wherein the at least one inlet duct and the outlet duct are connected to each other.
• An advantage of applying a design of the liquid conveying duct system of the insert in which the at least one inlet duct is oriented at an angle to the outlet duct, and in which the inlet duct is extending from one side of the insert to another is that a situation in which liquid might remain at an outlet of the insert is prevented.
• the inlet duct functions as a kind of shortcut, and liquid cannot reach the outlet of the insert unless a sucking and/or pressing force is applied.
• the device according to the present invention may further comprise means for sealing a space between an outer surface of a portion of the insert that is located inside the liquid conveying conduit of the flow through heater and an inner surface of the liquid conveying conduit.
• suitable sealing means By using suitable sealing means, leakage of liquid from the liquid conveying conduit through a (narrow) space between the outer surface of the insert and the inner surface of the conduit is prevented.
• the sealing means which may comprise an O-ring or the like, are located behind the inlet(s) of the liquid conveying duct system of the insert as seen in the flow direction of liquid in the flow through heater.
• the insert is described in general as an insert which is intended for use in the device for heating liquid as described in the foregoing, comprising:
• a duct system for conveying liquid through the insert wherein a diameter of the duct(s) of the liquid conveying duct system is significantly smaller than an outer diameter of the end portion.
• the liquid conveying duct system comprises at least two ducts which are oriented at an angle with respect to each other.
• the liquid conveying duct system comprises at least one duct for letting in liquid to the duct system, wherein this at least one inlet duct is oriented substantially perpendicular to an axial direction of the insert, i.e. a longitudinal direction of the insert, and is extending from one side of the insert to another; and a duct for letting out liquid from the duct system, wherein this outlet duct is oriented substantially parallel to the axial direction of the insert, and wherein the at least one inlet duct and the outlet duct are connected to each other.
• the insert further comprises a duct which is extending from an outer surface of the insert to the liquid conveying duct system, in another portion of the insert than the end portion which is suitable to be inserted in a conduit for conveying liquid.
• the sealing means which are preferably used for avoiding leakage of liquid from the liquid conveying conduit of the flow through heater may be provided as (a) component(s) of the insert.
• the insert further comprises means such as an O- ring which are suitable to be used for sealing a space between two surfaces, wherein these sealing means are located at the end portion which is suitable to be inserted in a conduit for conveying liquid.
• the present invention also provides a method for increasing accuracy at an outlet of a flow through heater having a conduit for conveying liquid and means for heating the liquid while flowing through the conduit, wherein at least a substantial portion of space which is present in a portion of the liquid conveying conduit of the flow through heater which is not directly associated with the heating means of the flow through heater is filled up by providing an insert and introducing at least a portion of the insert in the liquid conveying conduit into the flow through heater, at an outlet side of the flow through heater.
• the method according to the present invention is carried out, only little play is allowed between an inner surface of the liquid conveying conduit of the flow through heater and an outer surface of the portion of the insert that is inserted in the liquid conveying conduit.
• the insert which is applied when the method according to the present invention is carried out may be the insert as defined in the foregoing, or any other suitable insert, provided that a reduction of the dead volume can be achieved through an occupation of this volume, and that a flow of liquid is not blocked.
• figure 1 diagrammatically shows a flow through heater
• figure 2 diagrammatically shows a portion of a flow through heater and an insert according to the present invention
• figures 3 and 4 show views of two longitudinal sections of an end of a liquid conveying conduit of the flow through heater and the insert.
• Figure 1 diagrammatically shows a flow through heater 1 as known in the art.
• the flow through heater 1 comprises a conduit 2 for conveying liquid and heating elements 3 which are arranged such as to closely surround the liquid conveying conduit 2.
• a cross-sectional area of the liquid conveying conduit has a circular shape, which does not alter the fact that other shapes are possible as well.
• the heating elements 3 At both an inlet side and an outlet side of the flow through heater 1, a length 4 of the liquid conveying conduit 2 is not directly associated with the heating elements 3. These lengths 4 are referred to as ineffective portions 4 of the flow through heater 1.
• a liquid such as water is made to flow through the liquid conveying conduit 2, while the heating elements 3 are operated for supplying heat to the liquid in order to achieve an increase of the temperature of the liquid.
• Three important factors in achieving a desired temperature of the liquid at an outlet 5 of the flow through heater 1 are the initial temperature of the liquid, the flow rate, and the supply of heat.
• a delay in the feedback control loop due to the presence of an ineffective portion 4 at the outlet of the liquid conveying conduit 2 of the flow through heater 1, there is a delay in the feedback control loop, which has a negative influence on the accuracy of the temperature controlling process.
• the delay in the feedback control loop is directly related to the volume of the ineffective portion 4 at the outlet of the flow through heater 1, which is referred to as dead volume.
• dead volume the volume of the ineffective portion 4 at the outlet of the flow through heater 1, which is referred to as dead volume.
• the ineffective portion 4 has a length of 2 cm
• an inner diameter of the liquid conveying conduit 2 is 1 cm
• the flow rate is 5 ml/s
• the outlet temperature is detected at the outlet 5 of the flow through heater 1
• the delay time appears to be 0.314 s. This value is found by determining the dead volume, and dividing the dead volume by the flow rate.
• a dead volume of 1.57 ml is significant compared to a total volume. Therefore, in such cases, the dead volume has a significant influence on a final temperature of the beverage.
• the present invention proposes measurements to make the dead volume as small as possible. These measurements involve the application of an insert 6 which is partially inserted in the liquid conveying conduit 2 of the flow through heater 1, as is illustrated by figure 2 in which the insert 6 is indicated by dashed lines. Furthermore, figure 2 indicates an appropriate position of a temperature sensor 7, which is in a portion of the insert 6 right outside of the flow through heater 1.
• the insert 6 is preferably designed such as to remove as much of the dead volume as possible, while at the same time allowing for a required flow of liquid.
• the design of the insert 6 will be further elucidated on the basis of figures 3 and 4, in which longitudinal sections of the insert 6 are shown, as well as a portion of the liquid conveying conduit 2 of the flow through heater 1 , in which the insert 6 is partially inserted.
• the example of the insert 6 as shown in figures 3 and 4 comprises three portions.
• a first portion 8 is an end portion which is suitable to be located inside the ineffective portion 4 of the flow through heater 1. Hence, an outer diameter of this end portion 8 of the insert 6 is smaller than an inner diameter of the liquid conveying conduit 2 of the flow through heater 1.
• a second portion 9 is another end portion which allows for connection of a hose or the like to the insert 6, and has an outlet 10 for the liquid at its free end.
• a third portion 11 is an intermediate portion which is intended to be arranged such as to abut against an end of the liquid conveying conduit 2 of the flow through heater 1. Hence, an outer diameter of this intermediate portion 11 of the insert 6 is larger than an inner diameter of the liquid conveying conduit 2 of the flow through heater 1.
• a duct system 12 for conveying liquid through the insert 6 is arranged.
• the duct system 12 comprises two ducts 13a, 13b which are extending in a radial direction of the insert 6, i.e. a direction perpendicular to a flow direction of liquid in the flow through heater 1.
• These ducts 13 a, 13b serve for letting in liquid to the insert 6 and conveying the liquid to a central location inside the insert 6 where the ducts 13a, 13b are crossing. Extending from this location to the outlet 10 of the insert 6, an outlet duct 14 is present inside the insert 6.
• the flow direction of liquid in the flow through heater 1 is indicated by means of arrows in the figures.
• the insert 6 has a duct 15 for accommodating one or more components or portions of components (now shown in figures 3 and 4) which are to be used in a process of detecting the outlet temperature of liquid.
• this duct 15 will be referred to as detection duct 5.
• the detection duct 15 is arranged in the intermediate portion 11 of the insert 6, and is extending from an outer surface of the insert 6 to the outlet duct 14, in order to allow free access of the detection component(s) to liquid flowing through the outlet duct 14.
• the detection duct 15 has a radial orientation in the insert 6, like the inlet ducts 13a, 13b.
• sealing means are arranged between an inner surface of the conduit 2 and the outer surface of the insert 6, at a position behind the position where the inlet ducts 13a, 13b of the insert 6 are located.
• any suitable type of sealing means may be applied.
• the sealing means comprise an O-ring 16 which is accommodated in a groove that is arranged in the outer surface of the insert 6.
• Figures 3 and 4 show that the dimensions of the end portion 8 of the insert 6 which is suitable to be located inside the ineffective portion 4 of the flow through heater 1 are chosen such that only minimal space is present between an outer surface of this portion 8 of the insert 6 and the inner surface of the liquid conveying conduit 2 of the flow through heater 1 when the insert 6 is in its proper position.
• the volume causing delay in the detection of the outlet temperature of liquid is no more than a volume which is the sum of the space which is present between the outer surface of the inserted portion 8 of the insert 6 and the inner surface of the liquid conveying conduit 2 of the flow through heater 1, the volume of the inlet ducts 13a, 13b of the insert 6, and the volume of the outlet duct 14 between the connection to the inlet ducts 13a, 13b and the position of the detection duct 15.
• the diameters of the ducts 13a, 13b, 14 of the liquid conveying duct system 12 of the insert 6 are significantly smaller than the diameter of the liquid conveying conduit 2 of the flow through heater 1 at the outlet side of the flow through heater 1, so that the dead volume can actually be as small as possible. Due to the reduction of the dead volume of the ineffective portion 4 of the flow through heater 1, the present invention allows for an improved way of controlling the outlet temperature, which results in better performances of the devices in which the invention will be applied. Examples of such devices which are worthy of mention here are beverage making devices, in particular coffee devices and espresso devices of various types, including the drip filter type and the pad processing type, and baby milk devices.
• a conventional flow through heater 1 is provided, wherein the dead volume at the outlet side of the flow through heater 1 is reduced by providing the insert 6 according to the present invention and introducing the end portion 8 of the insert 6 into the liquid conveying conduit 2 of the flow through heater 1.
• a flow through heater 1 of common design an effective portion and two ineffective portions 4 located at ends of the flow through heater 1 can be discerned, wherein the ineffective portions 4 are portions where a liquid conveying conduit 2 of the flow through heater 1 is not directly associated with heating means 3 of the flow through heater 1.
• the ineffective portions 4 are portions where a liquid conveying conduit 2 of the flow through heater 1 is not directly associated with heating means 3 of the flow through heater 1.
• a volume of the ineffective portion 4 at the outlet 5 constitutes a dead volume which causes a delay in the feedback process, resulting in instability and inaccuracy of the temperature control. In order to prevent this, the delay should be minimized. Therefore, it is desired to detect the outlet temperature as quick as possible after the effective portion of the flow through heater 1 as seen in a flow direction of liquid in the flow through heater 1.
• the insert 6 comprises a duct system 12 for conveying liquid from the liquid conveying conduit 2 of the flow through heater 1 to an outlet 10 of the insert 6.
• a diameter of the duct(s) 13a, 13b, 14 of the liquid conveying duct system 12 is significantly smaller than a diameter of the liquid conveying conduit 2 of the flow through heater 1 at the outlet 5 of the flow through heater 1, so that a volume of the liquid conveying duct system 12 is relatively small, and the presence of the duct system 12 in the insert 6 does not spoil the dead volume reducing effect of the application of the insert 6.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Physics & Mathematics (AREA)
• Food Science & Technology (AREA)
• Instantaneous Water Boilers, Portable Hot-Water Supply Apparatuses, And Control Of Portable Hot-Water Supply Apparatuses (AREA)
• Pipe Accessories (AREA)
• Control Of Temperature (AREA)
• Measuring Volume Flow (AREA)
• Control Of Resistance Heating (AREA)

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Applications Claiming Priority (3)

Publications (1)

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• 2009
  • 2009-11-09 DE DE202009015187U patent/DE202009015187U1/de not_active Expired - Lifetime
  • 2009-11-11 EP EP09756061A patent/EP2359071A2/en not_active Withdrawn
  • 2009-11-11 US US13/128,285 patent/US20110217027A1/en not_active Abandoned
  • 2009-11-11 KR KR1020117013265A patent/KR20110095886A/ko not_active Application Discontinuation
  • 2009-11-11 WO PCT/IB2009/055013 patent/WO2010055472A2/en active Application Filing
  • 2009-11-11 RU RU2011123882/06A patent/RU2011123882A/ru not_active Application Discontinuation
  • 2009-11-11 JP JP2011543873A patent/JP2012515891A/ja not_active Withdrawn
  • 2009-11-11 CN CN2009801455266A patent/CN102317703A/zh active Pending
  • 2009-11-13 CN CN2009202693926U patent/CN201569131U/zh not_active Expired - Fee Related

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