EP0117425A1 - Signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like - Google Patents

Signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like Download PDF

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Publication number
EP0117425A1
EP0117425A1 EP84100705A EP84100705A EP0117425A1 EP 0117425 A1 EP0117425 A1 EP 0117425A1 EP 84100705 A EP84100705 A EP 84100705A EP 84100705 A EP84100705 A EP 84100705A EP 0117425 A1 EP0117425 A1 EP 0117425A1
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EP
European Patent Office
Prior art keywords
evaporator
sensor
plate
console
reflex
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Granted
Application number
EP84100705A
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German (de)
French (fr)
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EP0117425B1 (en
Inventor
Wilhelm Korsmeier
Klaus Klein
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EON Ruhrgas AG
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Ruhrgas AG
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Priority to AT84100705T priority Critical patent/ATE26170T1/en
Publication of EP0117425A1 publication Critical patent/EP0117425A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/02—Detecting the presence of frost or condensate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/11—Sensor to detect if defrost is necessary
    • F25B2700/111—Sensor to detect if defrost is necessary using an emitter and receiver, e.g. sensing by emitting light or other radiation and receiving reflection by a sensor

Definitions

  • the invention relates to a signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like.
  • the evaporator may freeze on the air side depending on the air humidity and air temperature.
  • the layer of frost deposited on the evaporator fins worsens the heat transfer from the air to the heat transfer medium that flows in cooled and has to be reheated in the evaporator, as a result of which the surface temperature of the evaporator drops and the air gaps between the evaporator fins can also increase due to the thickening layer of frost, and must therefore be defrosted are, for example by temporarily interrupting a further heat removal from the evaporator by the heat transfer medium.
  • the initiation of the defrosting process depending on the surface temperature or outside air temperature of the evaporator and whether a set temperature threshold value below which icing could occur is not sufficiently satisfactory and reliable. If the dew point in the evaporator on the air side and a temperature threshold value that has been adapted to it is not immediately necessary a layer of frost is formed, but initially only a layer of condensed water can emerge that drains off by itself and does not require a defrosting process that would unnecessarily interrupt the heat pump operation. If the temperature threshold value is set too low, the formation of a frost layer, which may already significantly impair the heat transfer, may have occurred before the temperature falls below it and the necessary defrosting process may start too late. The defrost time is also predefined.
  • the object of the invention is therefore to find a solution with which the defrosting process can be reliably initiated when there is a risk of icing and the formation of a frost layer and is ended when the frost layer has been defrosted.
  • the invention achieves this object by using a signal transmitter which monitors the evaporator and acts on the automatic defrosting device, which has a console made of heat-conducting material which can be fastened to the evaporator and a sensor block which is attached to the console and in which a temperature sensor touching the console and one on a frost formation point of the evaporator or the console-oriented optical reflex sensor are arranged, both of which can be connected to a signal receiver by signal lines.
  • This signal generator initiates the defrosting process by ANDing the signals generated by the two sensors in the correspondingly designed, amplifying signal receiver of the defrosting control device, which is preferably common to both sensors, if not only the temperature value measured by the temperature sensor on the evaporator surface, for example between O and minus 10 degrees Celsius set temperature threshold falls below and the temperature sensor generates a signal, but also the reflex sensor detects an actually occurring layer of frost by exceeding a set light reflection threshold value and thus generates a further signal.
  • the temperature signal of the temperature sensor and the reflex signal of the reflex sensor are canceled in the defrosting phase, i.e. the frost layer has thawed and the evaporator surface temperature has risen to such an extent that ice or frost can no longer be present, the defrosting process is ended by the defrosting device.
  • the signal transmitter of FIGS. 1 and 2 contains a bracket 1 made of heat-conducting material, for example copper, which can be attached to the evaporator and a sensor block 2, preferably made of plastic, attached to the bracket.
  • the sensor block 2 contains embedded a temperature sensor 3, which touches the console in a heat-conducting manner, and an optical reflex sensor 4, which emits light and responds to the reflection of light by an emerging frost layer.
  • the signal lines 5 of both sensors are moisture-tight from the sensor block 2 led out and connectable to a signal receiver.
  • the console 1 is designed as a plate which can be inserted into a gap 6 between two evaporator fins 7.
  • the sensor block 2 is attached to a plate bend 8, so that the reflex sensor 4 is aligned with its optical axis in an air gap 6 between two evaporator fins.
  • the optical axis of the reflex sensor which is essentially parallel to the evaporator fins 7, expediently runs close to the surface of an evaporator fin, so that the reflex sensor can detect a developing frost layer in good time.
  • the plate 1 has a trapezoidal shape, so that it can be inserted with its two plate edges 9 between two evaporator tubes 10 by clamping.
  • the plate 1 has break-off perforations 11 in one or more rows, so that the plate width between the wedge-shaped plate edges 9 can be adapted to larger differences in the distance between the evaporator tubes 10 by breaking off edge strips.
  • the temperature sensor 3 uses the plate 1 to measure both the temperature of the air flowing through the evaporator and the surface temperature of the evaporator.
  • the contact points between the plate edges 9 and the evaporator tubes 10 are not very large, as long as there is no frost or ice formation, but as soon as moisture falls below a dew point or at an even lower evaporator temperature, frost forms via the heat-conducting moisture or frost further heat flow possibility and ver With increasing icing, the connection and thus the heat conduction between the plate 1 and the evaporator improves. If the surface temperature of the evaporator determined by the temperature sensor via plate 1 drops below a set temperature threshold value at which a risk of icing can begin, a first signal is generated in the defrost control device by the temperature sensor.
  • a switching delay of the defrost control device can preferably be provided so that a short-term shortfall in the temperature threshold value and in excess of the light reflection threshold value does not yet lead to the defrosting process being initiated.
  • a switch for the termination of the defrosting process after canceling the temperature and the reflection signal - be provided without delay.
  • the formation of a frost layer by means of the reflex sensor can also be monitored in pulse mode if continuous operation of the light emitting diode of the reflex sensor is not desired.
  • the signal transmitter shown in FIGS. 3 and 4 functions in an analogous manner.
  • the plate-shaped console 1 contains an auxiliary reflective surface 12, on which a frost layer also forms when the evaporator is iced up, and the optical sensor 4 has its optical axis aligned with this auxiliary reflective surface 12.
  • the auxiliary reflective surface 12 is formed on its surface facing the reflex sensor 4 matt black, so that no light reflection and thus no output signal of the reflex sensor occurs if there is still no white, strong reflective frost formation has occurred or if there is only a transparent liquid condensation deposit on the matt black surface, which flows off by itself from the auxiliary reflecting surface 12 and does not require any defrost initiation.
  • the auxiliary reflecting surface 12 has a downwardly directed water drainage tip 13 on its lower edge.
  • An additionally provided, horizontally directed further water drainage tip improves the dripping off when the signal transmitter is used in a position rotated by 90 degrees becomes.
  • the auxiliary reflecting surface 12 has a reflecting point 14 which is curved toward the sensor block 2 and around which the water flows to the water outlet tip 13, so that the reflecting point 14 remains largely without a water film and reflects as little light as possible.
  • the signal transmitter can be conveniently arranged at the points where experience shows that, depending on the type and flow of the evaporator, one is most convenient by inserting the plate between evaporator fins and clamping between evaporator tubes, for example on the suction side of the evaporator icing or frost formation that disturbs the refrigeration cycle.
  • the type of icing of evaporators is strongly influenced by the state of the outside air.
  • the ice layer on the evaporator can be found in a color range from transparent (ice partly with water) to white.
  • the reflex sensor must recognize this area.
  • the reflex sensor should not only evaluate the degree of reflection, but also the reflection distance in order to detect the ice layer thicknesses. From these conditions it can be seen that the reflex sensor cannot always provide the correct signal without additional information.
  • the signal of the reflex sensor is clearly assigned to the state of the evaporator.
  • the signal from the reflex sensor means the presence of icing at low temperatures and the presence of water at positive temperatures.
  • the temperature is at most 0 0 C. Only when the temperature sensor reaches positive temperatures, the ice has melted and the defrosting process can then be ended at the right time.
  • the AND linkage of both signals is an important feature of the signal generator or defrost sensor.
  • the thickness of the ice layer is also determined with the reflex sensor.
  • the reflex sensor advantageously works in the infrared range and is clocked and a suitable light filter is arranged in front of the reflex sensor designated by the number 4 in FIGS. 1 and 3, which shields the reflex sensor against interfering light such as daylight or fluorescent lamps and thereby influences the reflex sensor incorrectly Flashing light switches off.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Defrosting Systems (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)

Abstract

1. A signal transmitter arrangement for controlling the defrosing of the air side of an evaporator means of a heat pump or the like comprising a sensing assembly consisting of a temperature sensing device for measuring the temperature on the surface of said evaporator means and a sensing device responding to the formation of frost or ice, said two sensing devices being coupled to a receiver for the transmission of signals, wherein said signal transmittal arrangement comprises a thermally conductive console (1) attachable to said evaporator means to which said sensing assembly (2) is connected, said temperature sensing device (3) being connected with said sensing assembly in a thermally conductive fashing, and wherein said sensing assembly comprises a photosensitive sensing device (4) constituting the second sensing device the optic axis of said photosensitive sensing device being aligned to an auxiliary matte black reflective surface (12) arranged vertically on said console, said reflective surface having a circular area of reflection (14) convex relative to said sensing assembly (2).

Description

Die Erfindung betrifft einen Signalgeber zur Steuerung des Abtauvorganges an der Luftseite des Verdampfers einer Wärmepumpe oder dergleichen. Zum Beispiel bei Wärmepumpen mit einem Luftwärme aufnehmenden Verdampfer kann es je nach Luftfeuchtigkeitsgehalt und Lufttemperatur zu einer Vereisung des Verdampfers an der Luftseite kommen. Die auf den Verdampferlamellen sich niederschlagende Reifschicht verschlechtert den Wärmeübergang von der Luft an das abgekühlt zufließende und im Verdampfer wieder zu erwärmende Wärmeträgermedium, wodurch die Oberflächentemperatur des Verdampfers absinkt und die Luftspalte zwischen den Verdampferlamellen auch durch die dicker werdende Reifschicht zuwachsen können, und muß daher abgetaut werden, beispielsweise durch vorübergehende Unterbrechung eines weiteren Wärmeentzugs aus dem Verdampfer durch das Wärmeträgermedium. Hierzu hat man bislang die Oberflächentemperatur des Verdampfers oder die Außenlufttemperatur kontrolliert, um mit einer automatischen zeitabhängigen Intervallabtausteuerungseinrichtung den Abtauvorgang einzuleiten, sobald der gemessene Temperaturwert einen in der Abtausteuerungseinrichtung eingestellten und vorgegebenen Schwellenwert unterschreitet. Die Einleitung des Abtauvorganges in Abhängigkeit davon, welche Oberflächentemperatur oder Außenlufttemperatur der Verdampfer hat und ob ein eingestellter Temperaturschwellenwert, bei dem eine Vereisung vorkommen könnte, unterschritten wird, ist jedoch nicht genügend befriedigend und zuverlässig. Wenn in dem Verdampfer luftseitig der Taupunkt und ein dazu angepaßter Temperaturschwellenwert unterschritten wird muß nicht sogleich schon eine Reifschicht entstehen, sondern kann zunächst nur eine Kondenswasserschicht entstehen, die von selbst abfließt und keinen Abtauvorgang erfordert, durch den der Wärmepumpenbetrieb unnötig unterbrochen würde. Bei zu niedrig eingestelltem Temperaturschwellenwert kann vor dessen Unterschreiten bereits die Bildung einer gegebenenfalls schon den Wärmeübergang erheblich verschlechternden Reifschicht eingetreten sein und kann der notwendige Abtauvorgang zu spät einsetzen. Außerdem wird die Abtauzeit fest vorgegeben.The invention relates to a signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like. For example, in the case of heat pumps with an evaporator that absorbs air heat, the evaporator may freeze on the air side depending on the air humidity and air temperature. The layer of frost deposited on the evaporator fins worsens the heat transfer from the air to the heat transfer medium that flows in cooled and has to be reheated in the evaporator, as a result of which the surface temperature of the evaporator drops and the air gaps between the evaporator fins can also increase due to the thickening layer of frost, and must therefore be defrosted are, for example by temporarily interrupting a further heat removal from the evaporator by the heat transfer medium. For this purpose, one has previously checked the surface temperature of the evaporator or the outside air temperature in order to initiate the defrosting process with an automatic time-dependent interval defrosting device as soon as the measured temperature value falls below a preset threshold value set in the defrosting device. However, the initiation of the defrosting process depending on the surface temperature or outside air temperature of the evaporator and whether a set temperature threshold value below which icing could occur is not sufficiently satisfactory and reliable. If the dew point in the evaporator on the air side and a temperature threshold value that has been adapted to it is not immediately necessary a layer of frost is formed, but initially only a layer of condensed water can emerge that drains off by itself and does not require a defrosting process that would unnecessarily interrupt the heat pump operation. If the temperature threshold value is set too low, the formation of a frost layer, which may already significantly impair the heat transfer, may have occurred before the temperature falls below it and the necessary defrosting process may start too late. The defrost time is also predefined.

Die Erfindung hat sich daher die Aufgabe gestellt, eine Lösung zu finden, mit der der Abtauvorgang zuverlässig bei Auftreten einer Vereisungsgefahr und Entstehen einer Reifschicht eingeleitet werden kann und bei erfolgtem Abtauen der Reifschicht beendet wird. Diese Aufgabe löst die Erfindung durch die Anwendung eines den Verdampfer überwachenden und auf die automatische Abtausteuerungseinrichtung einwirkenden Signalgebers, der eine an dem Verdampfer befestigbare Konsole aus wärmeleitendem Material und einen an der Konsole angebrachten Sensorblock aufweist, in dem ein wärmeleitend die Konsole berührender Temperatursensor und ein auf eine Reifbildungsstelle des Verdampfers oder der Konsole ausgerichteter optischer Reflexsensor angeordnet sind, die beide durch Signalleitungen mit einem Signalempfänger verbindbar sind. Mit diesem Signalgeber wird durch eine UND-Verknüpfung der von beiden Sensoren erzeugten Signale in dem entsprechend ausgebildeten, verstärkenden, vorzugsweise für beide Sensoren gemeinsamen Signalempfänger der Abtausteuerungseinrichtung der Abtauvorgang eingeleitet, wenn nicht nur der vom Temperatursensor gemessene Temperaturwert an der Verdampferoberfläche einen beispielsweise zwischen O und minus 10 Grad Celsius eingestellten Temperaturschwellenwert unterschreitet und der Temperatursensor ein Signal erzeugt, sondern außerdem auch noch vom Reflexsensor durch überschreiten eines eingestellten Lichtreflexionsschwellenwertes eine tatsächlich eingetretene Reifschicht festgestellt und so ein weiteres Signal erzeugt wird. Sobald in der Abtauphase das Temperatursignal des Temperatursensors und das Reflexsignal des Reflexsensors aufgehoben sind, das heißt die Reifschicht abgetaut ist und die Verdampferoberflächentemperatur so weit angestiegen ist, daß kein Eis oder Reif mehr vorhanden sein kann, wird der Abtauvorgang von der Abtausteuerungseinrichtung beendet.The object of the invention is therefore to find a solution with which the defrosting process can be reliably initiated when there is a risk of icing and the formation of a frost layer and is ended when the frost layer has been defrosted. The invention achieves this object by using a signal transmitter which monitors the evaporator and acts on the automatic defrosting device, which has a console made of heat-conducting material which can be fastened to the evaporator and a sensor block which is attached to the console and in which a temperature sensor touching the console and one on a frost formation point of the evaporator or the console-oriented optical reflex sensor are arranged, both of which can be connected to a signal receiver by signal lines. This signal generator initiates the defrosting process by ANDing the signals generated by the two sensors in the correspondingly designed, amplifying signal receiver of the defrosting control device, which is preferably common to both sensors, if not only the temperature value measured by the temperature sensor on the evaporator surface, for example between O and minus 10 degrees Celsius set temperature threshold falls below and the temperature sensor generates a signal, but also the reflex sensor detects an actually occurring layer of frost by exceeding a set light reflection threshold value and thus generates a further signal. As soon as the temperature signal of the temperature sensor and the reflex signal of the reflex sensor are canceled in the defrosting phase, i.e. the frost layer has thawed and the evaporator surface temperature has risen to such an extent that ice or frost can no longer be present, the defrosting process is ended by the defrosting device.

Der erfindungsgemäße Signalgeber und seine wirkungsweise sowie vorteilhafte Ausgestaltungsformen werden nachstehend anhand der Zeichnung von zwei Ausführungsbeispielen näher erläutert. In der Zeichnung zeigt

  • Figur 1 ein erstes Ausführungsbeispiel des Signalgebers in perspektivischer Darstellung,
  • Figur 2 den in einen Verdampfer eingesetzten Signalgeber der Figur 1 in der Ansicht von oben,
  • Figur 3 ein zweites Ausführungsbeispiel in perspektivischer Darstellung,
  • Figur 4 den in einen Verdampfer eingesetzten Signalgeber der Figur 3 in der Ansicht von unten.
The signal generator according to the invention and its mode of operation and advantageous embodiments are explained in more detail below with reference to the drawing of two exemplary embodiments. In the drawing shows
  • FIG. 1 shows a first exemplary embodiment of the signal transmitter in a perspective view,
  • FIG. 2 shows the signal transmitter of FIG. 1 inserted into an evaporator in a view from above,
  • FIG. 3 shows a second exemplary embodiment in perspective,
  • Figure 4 shows the signal transmitter used in an evaporator of Figure 3 in the view from below.

Der Signalgeber der Figuren 1 und 2 enthält eine am Verdampfer befestigbare Konsole 1 aus wärmeleitendem Material, zum Beispiel Kupfer, und einen an der Konsole angebrachten Sensorblock 2 vorzugsweise aus Kunststoff. Der Sensorblock 2 enthält eingebettet einen Temperatursensor 3, der wärmeleitend die Konsole berührt, und einen optischen Reflexsensor 4, der Licht aussendet und auf die Lichtreflexion durch eine entstehende Reifschicht anspricht. Die Signalleitungen 5 beider Sensoren sind feuchtigkeitsdicht aus dem Sensorblock 2 herausgeführt und mit einem Signalempfänger verbindbar. Die Konsole 1 ist als Platte ausgebildet, die in eine Lücke 6 zwischen zwei Verdampferlamellen 7 einführbar ist. Der Sensorblock 2 ist an einer Plattenabwinkelung 8 befestigt, so daß der Reflexsensor 4, mit seiner optischen Achse in einen Luftspalt 6 zwischen zwei Verdampferlamellen ausgerichtet ist. Die zu den Verdampferlamellen 7 im wesentlichen parallele optische Achse des Reflexsensors verläuft zweckmäßigerweise nahe an der Oberfläche einer Verdampferlamelle, damit der Reflexsensor rechtzeitig eine entstehende Reifschicht feststellen kann. Zur einfachen Befestigung des Signalgebers an dem Verdampfer hat die Platte 1 eine Trapezform, so daß sie mit ihren beiden Plattenrändern 9 zwischen zwei Verdampferröhren 10 klemmend eingesteckt werden kann. Wenigstens längs eines Plattenrandes 9 besitzt die Platte 1 Abbrechperforationen 11 in einer oder mehreren Reihen, so daß sich die Plattenbreite zwischen den keilförmig zueinander verlaufenden Plattenrändern 9 durch Abbrechen von Randstreifen an größere Unterschiede des Abstandes zwischen den Verdampferröhren 10 anpassen läßt. Der Temperatursensor 3 mißt über die Platte 1 sowohl die Temperatur der den Verdampfer durchströmenden Luft als auch die Oberflächentemperatur des Verdampfers. Die Berührungsstellen zwischen den Plattenrändern 9 und den Verdampferröhren 10 sind, solange keine Reif- oder Eisbildung vorhanden ist, nicht sehr groß, sobald jedoch bei einer Taupunktunterschreitung ein Feuchtigkeitsniederschlag oder bei noch tieferer Verdampfertemperatur eine Reifbildung auftritt, entsteht über die wärmeleitende Feuchtigkeit beziehungsweise den Reif eine weitere Wärmeflußmöglichkeit und verbessert sich mit zunehmender Vereisung die Verbindung und damit die Wärmeleitung zwischen der Platte 1 und dem Verdampfer. Sinkt die vom Temperatursensor über die Platte 1 festgestellte Oberflächentemperatur des Verdampfers unter einen eingestellten Temperaturschwellenwert ab, bei dem eine Vereisungsgefahr beginnen kann, entsteht in der Abtausteuerungseinrichtung durch den Temperatursensor ein erstes Signal. Erst wenn der Reflexsensor auf eine entstehende,reflektierende Reifschicht anspricht und ein zweites Signal erzeugt, wird der Abtauvorgang eingeleitet. Hierbei kann vorzugsweise eine Schaltverzögerung der Abtausteuerungseinrichtung vorgesehen sein, damit eine kurzfristige Unterschreitung des Temperaturschwellenwertes und überschreitung des Lichtreflexionsschwellenwertes noch nicht zu einer Einleitung des Abtauvorganges führen. Gleichartig kann auch für die Beendigung des Abtauvorganges nach Aufhebung des Temperatur- und des Reflexionssignals eine Schalt- verzögerung vorgesehen werden. Die Überwachung einer Reifschichtbildung mittels des Reflexsensors kann auch im Impulsbetrieb stattfinden, falls ein Dauerbetrieb der Lichtsendediode des Reflexsensors nicht gewünscht wird.The signal transmitter of FIGS. 1 and 2 contains a bracket 1 made of heat-conducting material, for example copper, which can be attached to the evaporator and a sensor block 2, preferably made of plastic, attached to the bracket. The sensor block 2 contains embedded a temperature sensor 3, which touches the console in a heat-conducting manner, and an optical reflex sensor 4, which emits light and responds to the reflection of light by an emerging frost layer. The signal lines 5 of both sensors are moisture-tight from the sensor block 2 led out and connectable to a signal receiver. The console 1 is designed as a plate which can be inserted into a gap 6 between two evaporator fins 7. The sensor block 2 is attached to a plate bend 8, so that the reflex sensor 4 is aligned with its optical axis in an air gap 6 between two evaporator fins. The optical axis of the reflex sensor, which is essentially parallel to the evaporator fins 7, expediently runs close to the surface of an evaporator fin, so that the reflex sensor can detect a developing frost layer in good time. For easy attachment of the signal generator to the evaporator, the plate 1 has a trapezoidal shape, so that it can be inserted with its two plate edges 9 between two evaporator tubes 10 by clamping. At least along a plate edge 9, the plate 1 has break-off perforations 11 in one or more rows, so that the plate width between the wedge-shaped plate edges 9 can be adapted to larger differences in the distance between the evaporator tubes 10 by breaking off edge strips. The temperature sensor 3 uses the plate 1 to measure both the temperature of the air flowing through the evaporator and the surface temperature of the evaporator. The contact points between the plate edges 9 and the evaporator tubes 10 are not very large, as long as there is no frost or ice formation, but as soon as moisture falls below a dew point or at an even lower evaporator temperature, frost forms via the heat-conducting moisture or frost further heat flow possibility and ver With increasing icing, the connection and thus the heat conduction between the plate 1 and the evaporator improves. If the surface temperature of the evaporator determined by the temperature sensor via plate 1 drops below a set temperature threshold value at which a risk of icing can begin, a first signal is generated in the defrost control device by the temperature sensor. Only when the reflex sensor responds to an emerging, reflecting layer of frost and generates a second signal, the defrosting process is initiated. In this case, a switching delay of the defrost control device can preferably be provided so that a short-term shortfall in the temperature threshold value and in excess of the light reflection threshold value does not yet lead to the defrosting process being initiated. Similarly, a switch for the termination of the defrosting process after canceling the temperature and the reflection signal - be provided without delay. The formation of a frost layer by means of the reflex sensor can also be monitored in pulse mode if continuous operation of the light emitting diode of the reflex sensor is not desired.

In analoger Weise funktioniert der in den Figuren 3 und 4 dargestellte Signalgeber. Hier jedoch enthält die plattenförmige Konsole 1 eine Hilfsreflexfläche 12, auf der sich bei einer Vereisung des Verdampfers ebenfalls eine Reifschicht bildet, und ist der Reflexsensor 4 mit seiner optischen Achse auf diese Hilfsreflexfläche 12 ausgerichtet. Die Hilfsreflexfläche 12 ist auf ihrer dem Reflexsensor 4 zugekehrten Oberfläche mattschwarz ausgebildet, damit keine Lichtreflexion und somit auch kein Ausgangssignal des Reflexsensors auftritt, wenn noch keine weiße, stark reflektierende Reifbildung eingetreten ist oder wenn erst auf dem mattschwarzen Untergrund ein durchsichtiger flüssiger Kondensniederschlag vorliegt, der von selbst von der Hilfsreflexfläche 12 abfließt und keine Abtaueinleitung erfordert. Um das Abtropfen von Wasser von der vertikal verlaufenden Hilfsreflexfläche 12 zu fördern, hat die Hilfsreflexfläche 12 an ihrer Unterkante eine abwärts gerichtete Wasserablaufspitze 13. Eine zusätzlich vorgesehene, horizontal gerichtete weitere Wasserablaufspitze verbessert das Abtropfen, wenn der Signalgeber in einer um 90 Grad verdrehten Position angewendet wird. Ferner besitzt die Hilfsreflexfläche 12 einen zum Sensorblock 2 hin gewölbt ausgebildeten Reflexpunkt 14, um den herum das Wasser zur Wasserablaufspitze 13 fließt, so daß der Reflexpunkt 14 weitgehend ohne Wasserfilm bleibt und möglichst wenig Licht reflektiert.The signal transmitter shown in FIGS. 3 and 4 functions in an analogous manner. Here, however, the plate-shaped console 1 contains an auxiliary reflective surface 12, on which a frost layer also forms when the evaporator is iced up, and the optical sensor 4 has its optical axis aligned with this auxiliary reflective surface 12. The auxiliary reflective surface 12 is formed on its surface facing the reflex sensor 4 matt black, so that no light reflection and thus no output signal of the reflex sensor occurs if there is still no white, strong reflective frost formation has occurred or if there is only a transparent liquid condensation deposit on the matt black surface, which flows off by itself from the auxiliary reflecting surface 12 and does not require any defrost initiation. In order to promote the dripping of water from the vertically running auxiliary reflecting surface 12, the auxiliary reflecting surface 12 has a downwardly directed water drainage tip 13 on its lower edge. An additionally provided, horizontally directed further water drainage tip improves the dripping off when the signal transmitter is used in a position rotated by 90 degrees becomes. Furthermore, the auxiliary reflecting surface 12 has a reflecting point 14 which is curved toward the sensor block 2 and around which the water flows to the water outlet tip 13, so that the reflecting point 14 remains largely without a water film and reflects as little light as possible.

Mit der dargestellten und beschriebenen Ausbildung der Konsole als Platte kann der Signalgeber durch Einführen der Platte zwischen Verdampferlamellen und Einklemmen zwischen Verdampferröhren zum Beispiel an der Ansaugseite des Verdampfers bequem an denjenigen Stellen angeordnet werden, an denen je nach Art und Durchströmung des Verdampfers erfahrungsgemäß am ehesten eine den Kältekreislauf störende Vereisung beziehungsweise Reifbildung eintritt.With the illustrated and described design of the console as a plate, the signal transmitter can be conveniently arranged at the points where experience shows that, depending on the type and flow of the evaporator, one is most convenient by inserting the plate between evaporator fins and clamping between evaporator tubes, for example on the suction side of the evaporator icing or frost formation that disturbs the refrigeration cycle.

Die Art der Vereisung von Verdampfern wird stark von dem jeweiligen Zustand der Außenluft beeinflußt. Die Eisschicht am Verdampfer ist in einem Farbbereich von transparent (Eis zum Teil mit Wasser) bis weiß anzutreffen. Diesen Bereich muß der Reflexsensor erkennen. Ferner soll der Reflexsensor nicht nur den Reflexionsgrad, sondern auch den Reflexionsabstand auswerten, um die Eisschichtstärken zu erfassen. Aus diesen Bedingungen heraus ist zu erkennen, daß der Reflexsensor ohne eine zusätzliche Information nicht immer das richtige Signal liefern kann. Mit Hilfe des Temperatursensors wird das Signal des Reflexsensors dem Zustand des Verdampfers eindeutig zugeordnet. So zum Beispiel bedeutet das Signal des Reflexsensors bei niedrigen Temperaturen das Vorhandensein einer Vereisung und bei positiven Temperaturen ein Vorhandensein von Wasser. Solange beim Abtauvorgang noch Eis vorhanden ist, beträgt die Temperatur höchstens 00 C. Erst wenn der Temperatursensor positive Temperaturen erreicht, ist das Eis geschmolzen und kann dann der Abtauvorgang zur richtigen Zeit beendet werden. Die UND-Verknüpfung beider Signale ist ein wichtiges Merkmal des Signalgebers beziehungsweise Abtausensors. Mit dem Reflexsensor wird auch die Stärke der Eisschicht bestimmt. Vorteilhafterweise arbeitet der Reflexsensor im Infrarotbereich und wird er getaktet und wird vor dem in den Figuren 1 und 3 mit der Ziffer 4 bezeichneten Reflexsensor ein geeignetes Lichtfilter angeordnet, welches den Reflexsensor gegen Störlicht wie zum Beispiel Tageslicht oder Leuchtstofflampen, abschirmt und dadurch Fehlbeeinflussungen des Reflexsensors durch Störlicht ausschaltet.The type of icing of evaporators is strongly influenced by the state of the outside air. The ice layer on the evaporator can be found in a color range from transparent (ice partly with water) to white. The reflex sensor must recognize this area. Furthermore, the reflex sensor should not only evaluate the degree of reflection, but also the reflection distance in order to detect the ice layer thicknesses. From these conditions it can be seen that the reflex sensor cannot always provide the correct signal without additional information. With the help of the temperature sensor, the signal of the reflex sensor is clearly assigned to the state of the evaporator. For example, the signal from the reflex sensor means the presence of icing at low temperatures and the presence of water at positive temperatures. As long as there is still ice during the defrosting process, the temperature is at most 0 0 C. Only when the temperature sensor reaches positive temperatures, the ice has melted and the defrosting process can then be ended at the right time. The AND linkage of both signals is an important feature of the signal generator or defrost sensor. The thickness of the ice layer is also determined with the reflex sensor. The reflex sensor advantageously works in the infrared range and is clocked and a suitable light filter is arranged in front of the reflex sensor designated by the number 4 in FIGS. 1 and 3, which shields the reflex sensor against interfering light such as daylight or fluorescent lamps and thereby influences the reflex sensor incorrectly Flashing light switches off.

Claims (4)

1. Signalgeber zur Steuerung des Abtauvorganges an der Luftseite des Verdampfers einer Wärmepumpe oder dergleichen, dadurch gekennzeichnet, daß der Signalgeber eine an dem Verdampfer befestigbare Konsole (1) aus wärmeleitendem Material und einen an der Konsole angebrachten Sensorblock (2) aufweist, in dem ein wärmeleitend die Konsole berührender Temperatursensor (3) und ein auf eine Reifbildungsstelle des Verdampfers oder der Konsole ausgerichteter optischer Reflexsensor (4) angeordnet sind, die beide durch Signalleitungen (5) mit einem Signalempfänger verbindbar sind.1. Signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like, characterized in that the signal transmitter has a bracket (1) made of heat-conducting material and an attached to the console sensor block (2), in which a A temperature sensor (3) contacting the console in a heat-conducting manner and an optical reflex sensor (4) aligned with a frost formation point of the evaporator or the console, both of which can be connected to a signal receiver by signal lines (5). 2. Signalgeber nach Anspruch 1, dadurch gekennzeichnet, daß die Konsole aus einer Platte (1) besteht, die zwischen zwei Verdampferlamellen einführbar und mit gegenüberliegenden Plattenrändern (9) zwischen zwei Verdampferröhren einklemmbar ist, und daß der Reflexsensor (4) des Sensorblocks (2) mit seiner optischen Achse in den Luftspalt zwischen zwei Verdampferlamellen im wesentlichen parallel zu diesen verlaufend ausgerichtet ist.2. Signal generator according to claim 1, characterized in that the console consists of a plate (1) which can be inserted between two evaporator fins and with opposite plate edges (9) between two evaporator tubes, and that the reflex sensor (4) of the sensor block (2nd ) is aligned with its optical axis in the air gap between two evaporator fins essentially parallel to these. 3. Signalgeber nach Anspruch 1, dadurch gekennzeichnet, daß die Konsole aus einer Platte (1) besteht, die zwischen zwei Verdampferlamellen einführbar ist und mit gegenüberliegenden Plattenrändern (9) zwischen zwei Verdampferröhren einklemmbar ist, daß die Platte eine vertikal verlaufende, mattschwarze Hilfsreflexfläche (12) aufweist, die vorzugsweise mit einem zum Sensorblock (2) hin gewölbt ausgebildeten Reflexpunkt (14) versehen ist und vorzugsweise eine an ihrer Unterkante abwärts gerichtete Wasserablaufspitze (13)enthält, und daß der Reflexsensor (4) des Sensorblocks (2) mit seiner optischen Achse auf die Hilfsreflexfläche (12) ausgerichtet ist.3. Signal generator according to claim 1, characterized in that the console consists of a plate (1) which can be inserted between two evaporator fins and with opposite plate edges (9) can be clamped between two evaporator tubes, that the plate has a vertically running, matt black auxiliary reflex surface ( 12), which preferably with a Sensor block (2) is arched reflex point (14) and preferably contains a downward-directed water drainage tip (13), and that the reflex sensor (4) of the sensor block (2) is aligned with its optical axis on the auxiliary reflex surface (12) is. 4. Signalgeber nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß die die Verdampferröhren berührenden Plattenränder (9) keilförmig zueinander verlaufen und die Platte (1) längs wenigstens eines Plattenrandes Abbrechperforationen (11) aufweist.4. Signal generator according to claim 2 or 3, characterized in that the plate edges touching the evaporator tubes (9) extend in a wedge shape to one another and the plate (1) has break-off perforations (11) along at least one plate edge.
EP84100705A 1983-01-29 1984-01-24 Signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like Expired EP0117425B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84100705T ATE26170T1 (en) 1983-01-29 1984-01-24 SIGNALS FOR CONTROLLING THE DEFROSTING PROCESS ON THE AIR SIDE OF THE EVAPORATOR OF A HEAT PUMP OR SIMILAR.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3303054 1983-01-29
DE3303054A DE3303054C2 (en) 1983-01-29 1983-01-29 Signal generator for controlling the defrosting of the evaporator of a heat pump

Publications (2)

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EP0117425A1 true EP0117425A1 (en) 1984-09-05
EP0117425B1 EP0117425B1 (en) 1987-03-25

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EP84100705A Expired EP0117425B1 (en) 1983-01-29 1984-01-24 Signal transmitter for controlling the defrosting process on the air side of the evaporator of a heat pump or the like

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EP (1) EP0117425B1 (en)
AT (1) ATE26170T1 (en)
DE (1) DE3303054C2 (en)
NO (1) NO158269C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007072523A1 (en) * 2005-12-19 2007-06-28 Ixfin S.P.A. System for automated defrosting of a refrigerating apparatus
ITPD20120148A1 (en) * 2012-05-10 2013-11-11 Enerblue S R L HEAT PUMP AND AUTOMATIC DEFROSTING METHOD OF CHECKING A HEAT PUMP

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112303947A (en) * 2020-11-02 2021-02-02 中科美菱低温科技股份有限公司 Double-evaporator refrigeration system, refrigeration equipment and control method of refrigeration system of refrigeration equipment

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2453140A1 (en) * 1973-11-08 1975-05-15 Upo Oy DEVICE FOR MONITORING THE FORMATION AND DEFROSTING OF TIRE MATERIALS ON THE COOLING ELEMENTS OF A REFRIGERATING SYSTEM
DE2637129A1 (en) * 1976-08-18 1978-02-23 Bosch Gmbh Robert DEVICE FOR DEFROSTING EVAPORATORS IN REFRIGERANT CIRCUITS, IN PARTICULAR OF HEAT PUMPS
GB2068100A (en) * 1980-01-12 1981-08-05 Danfoss As Defrosting equipment
EP0066862A1 (en) * 1981-06-08 1982-12-15 Russell Coil Company Demand defrost system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3280577A (en) * 1963-11-20 1966-10-25 Matsushita Electric Ind Co Ltd Automatic defrosting control device
DD152404A1 (en) * 1980-07-28 1981-11-25 Dieter Voekler DEFROST CONTROL FOR THE INTRODUCTION OF DEFROSTING FOR COOLANT EVAPORATOR
EP0082144B1 (en) * 1981-06-26 1986-08-27 ALSENZ, Richard H. Refrigerator defrost control

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2453140A1 (en) * 1973-11-08 1975-05-15 Upo Oy DEVICE FOR MONITORING THE FORMATION AND DEFROSTING OF TIRE MATERIALS ON THE COOLING ELEMENTS OF A REFRIGERATING SYSTEM
DE2637129A1 (en) * 1976-08-18 1978-02-23 Bosch Gmbh Robert DEVICE FOR DEFROSTING EVAPORATORS IN REFRIGERANT CIRCUITS, IN PARTICULAR OF HEAT PUMPS
GB2068100A (en) * 1980-01-12 1981-08-05 Danfoss As Defrosting equipment
EP0066862A1 (en) * 1981-06-08 1982-12-15 Russell Coil Company Demand defrost system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007072523A1 (en) * 2005-12-19 2007-06-28 Ixfin S.P.A. System for automated defrosting of a refrigerating apparatus
ITPD20120148A1 (en) * 2012-05-10 2013-11-11 Enerblue S R L HEAT PUMP AND AUTOMATIC DEFROSTING METHOD OF CHECKING A HEAT PUMP

Also Published As

Publication number Publication date
NO840332L (en) 1984-07-30
EP0117425B1 (en) 1987-03-25
ATE26170T1 (en) 1987-04-15
NO158269B (en) 1988-05-02
DE3303054A1 (en) 1984-08-02
DE3303054C2 (en) 1994-02-10
NO158269C (en) 1988-08-10

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