WO1995005227A1 - Falling film evaporator with an automatic cleaning system - Google Patents

Falling film evaporator with an automatic cleaning system Download PDF

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Publication number
WO1995005227A1
WO1995005227A1 PCT/DE1994/000938 DE9400938W WO9505227A1 WO 1995005227 A1 WO1995005227 A1 WO 1995005227A1 DE 9400938 W DE9400938 W DE 9400938W WO 9505227 A1 WO9505227 A1 WO 9505227A1
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WO
WIPO (PCT)
Prior art keywords
falling film
brushes
film evaporator
cleaning
heat exchanger
Prior art date
Application number
PCT/DE1994/000938
Other languages
German (de)
French (fr)
Inventor
Yuyao Qin
Original Assignee
Yuyao Qin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yuyao Qin filed Critical Yuyao Qin
Publication of WO1995005227A1 publication Critical patent/WO1995005227A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
    • F28G1/00—Non-rotary, e.g. reciprocated, appliances
    • F28G1/16—Non-rotary, e.g. reciprocated, appliances using jets of fluid for removing debris
    • F28G1/163—Non-rotary, e.g. reciprocated, appliances using jets of fluid for removing debris from internal surfaces of heat exchange conduits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto 
    • B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
    • B08B9/027—Cleaning the internal surfaces; Removal of blockages
    • B08B9/04—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes
    • B08B9/053—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction
    • B08B9/055—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction the cleaning devices conforming to, or being conformable to, substantially the same cross-section of the pipes, e.g. pigs or moles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto 
    • B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
    • B08B9/027—Cleaning the internal surfaces; Removal of blockages
    • B08B9/04—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes
    • B08B9/053—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction
    • B08B9/057—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes moved along the pipes by a fluid, e.g. by fluid pressure or by suction the cleaning devices being entrained discrete elements, e.g. balls, grinding elements, brushes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
    • F28G1/00—Non-rotary, e.g. reciprocated, appliances
    • F28G1/02—Non-rotary, e.g. reciprocated, appliances having brushes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination

Definitions

  • the invention which mainly consists of three different assemblies (product distribution system, heat exchanger and automatic cleaning system), has two exemplary embodiments, which are described below.
  • the first embodiment is shown in Fig.la and Fig.lb.
  • the product distribution system is designed as a flat, rectangular container with both ends closed.
  • flat jet nozzles (7 in Fig. La) are arranged in rows, the number of which is equal to the number of evaporator chambers (10 in Fig.la).
  • the center lines of the rows are in the planes of symmetry of the associated evaporator chambers.
  • the nozzles in a row are at a distance of 35-45 mm and alternately spray in the vertical direction on two sides of the evaporator chamber with an inclination angle of approximately 20 °.
  • the shape of the spray generated with the flat jet nozzle is flat and fan-shaped with a mist cone angle of approximately 110 °.
  • the amount sprayed depends on the type of nozzle, the pressure in the product distribution system and the physical properties of the product.
  • the mass distribution of the spray mist of a nozzle transversely to the main spray cone axis corresponds approximately to a normal distribution.
  • the angle of inclination of the nozzles (approx. 20 °), the spray cone angle (110 °), the distance between two neighboring nozzles and the distance between the nozzles and the evaporator chamber surfaces are matched to one another in such a way that at least a 20 percent overlap of the spray fog is guaranteed by two neighboring nozzles working in the same direction. This leads to an even distribution of the liquid on the walls of the evaporator chambers.
  • the distribution system has the advantage that the falling film produced thereby has a high initial speed.
  • the heat exchanger with a rectangular outer shape consists of a series of narrow, rectangular chambers and has a surface with ribbed plates on the steam side. At the upper end of the heat exchanger, where the spray mist hits the heat exchanger surfaces, the distribution of the liquid is very uneven, so that there is an increased risk of fouling here. In order to prevent fouling processes as much as possible, an approximately 0.1m high cooling zone (8 in Fig.la) is arranged in this area, which makes it possible to cool this part of the heat exchanger.
  • the automatic cleaning system consists of cleaning brushes (16 in Fig. Lb), brush heads (18 in Fig. Lb), distribution brushes (19 in Fig.
  • Each drive rod is sealed against the bottom of the heat exchanger with a rubber seal.
  • Each evaporation chamber is assigned a brush which is adapted to the width and length of the chamber and which is mounted on a brush head.
  • the brush heads are supported by two drive rods mounted on the two distributor pipes. All brush heads, drive rods and distributor pipes are hollow. Holes with a diameter of approx. 3 mm are made on the long sides of the brush heads (17 in Fig.lb).
  • the distance between two neighboring holes is approx.15mm.
  • the liquid product pumped in during the cleaning phase can escape through the product inlet, distribution pipes, drive rods, brush heads and through the small holes. All brushes, brush heads, drive rods and the two distribution pipes form a rigid body that moves up and down during operation in freely selectable time intervals by means of a motor, gear mechanism and spindle drive becomes.
  • a cleaning cycle takes about 30 seconds. The brushes then remain in their resting position on the bottom of the evaporator until the next cleaning cycle (SS in Fig. La).
  • SS in Fig. La the next cleaning cycle
  • the following measures are taken: a)
  • the cleaning brushes are designed so that triangular between the bristles
  • liquid film produced by the nozzle distribution system has a falling speed higher than the speed of the downward moving brushes, no dry surfaces are created when the brushes move downward.
  • the second embodiment is shown in Fig.2 and Fig.3.
  • the product distribution system consists of a distribution plate (8 in Fig.2) and distribution pipes (9 in Fig.2).
  • the rooms separated by the distribution plate are connected to each other by two pipes (7 in Fig.2).
  • the walls of the evaporator chamber protrude into the lower room.
  • V-shaped recesses are arranged on the upper edge of the walls of the evaporator chamber (see detail Y in Fig. 3).
  • the liquid product flows through the distribution plate through the distribution pipes to the upper end of the heat exchanger. It is evenly distributed through the V-shaped recesses at the upper end of the evaporator chamber and flows down in a thin film under the influence of gravity.
  • the heat exchanger has a rectangular outer shape.
  • Its evaporator chamber consists of a series of narrow, rectangular and vertical chamber elements, which are connected in the middle by a narrow, orthogonal chamber (see section I - L in Fig.2).
  • the evaporator chamber is delimited by corrugated plates on both sides and ribbed on the steam side by needles or drilled plates, so that on the one hand the stability of the evaporator chamber walls is increased and on the other hand the heat transfer coefficient is improved. It is possible to manufacture the main part of the heat exchanger by soldering in a salt bath.
  • the automatic cleaning system consists of cleaning brushes (11 in Fig.2), a brush head (12 in Fig.2), distribution brushes (13 in Fig.2), two drive rods (6 in Fig.2), a crossbar (4 in Fig. 2), a spindle drive (3 in Fig.2) and gear transmission system (1 in Fig.2) with motor and control system (2 in Fig.2).
  • the two drive rods are sealed against the evaporator cover with a rubber seal.
  • the brush head which is supported by the two drive rods mounted on the crossbar, has the same shape as the evaporator chamber (see Fig. 4).
  • Two cleaning brushes (see Fig. 5) and distribution brushes, which are mounted on the top and bottom of the brush head, are assigned to each evaporator chamber element.
  • All brushes, the brush head, the crossbar and the two drive rods form a rigid body, which is moved occasionally by the motor, gear mechanism and spindle drive during operation at freely selectable time intervals in order to clean all heat exchanger surfaces twice.
  • the cleaning brushes move between positions SS and EE in Fig.2.
  • a cleaning cycle takes about 30 seconds.
  • the brushes then remain in their rest position until the next cleaning cycle, which is located in the evaporator cover between the distribution pipes (position SS in Fig. 2).
  • On two opposite walls of the evaporator cover and the evaporator bottom are the guide grooves (5 and 15 in Fig. 2), which are adapted in size, number and position to the evaporator chamber elements, and which ensure the problem-free movement of the cleaning brushes as they enter and exit the evaporator chamber , arranged.
  • the cleaning plates (10 in Fig. 2) are welded to the distribution pipes. Two cleaning plates are assigned to each cleaning brush. The length of the plate and the distance between these two plates adapt to the brush geometry. About 2mm long, conical spikes are arranged on the convex working surfaces of the cleaning plates (see detail Y in Fig.3). As a result, the cleaning brushes move as the cleaning system moves up and down partly mechanically dehumidified and cleaned.
  • the speed of the cleaning system during the downward movement is greater than the flow speed of the product film, dry surfaces are created. For this reason, the speed of the cleaning brushes moving downwards is set low at approx.0.5m high upper area of the evaporation chamber in order to minimize or avoid the formation of dry surfaces.
  • the evaporator chamber is separated into two rooms by the cleaning brushes, which are connected to one another by bores (14 in Fig. 2) in order to minimize pressure differences that occur.
  • all of the heat exchanger surfaces can be cleaned online by the clocked movement of the automatic cleaning system without interrupting the production process, and the fouling resistances can thus be kept to almost zero.

Abstract

The enduring fouling occurring at the heat exchange surfaces of known falling film evaporators causes big costs. A new falling film evaporator with automatic cleaning system should prevent such enduring fouling from occurring during the production process or reduce it almost to zero. The heat exchanger surfaces of the falling film evaporator, which on the steam side are finely ribbed, may be continuously cleaned during the production process by an automatic cleaning system which mainly consists of a brush head adapted to the dimensions of the evaporation chamber and of cleaning and distributing brushes mounted thereon. The brushes are moved up and down at freely selectable intervals by means of a driving system. The falling film evaporator is suitable for evaporating and concentrating liquid products in the chemical and food processing industry, for example for desalinating sea water.

Description

Beschreibung Fallfilmverdampfer mit automatischem Reinigungssystem Description Falling film evaporator with automatic cleaning system
Es ist bekannt, daß technische Fallfilmverdampfer gewöhnlich aus einem Bündel senk¬ rechter Rohre, auf deren Innenseite ein siedender Flüssigkeitsfilm unter dem Einfluß der Schwerkraft herabfließt, bestehen. Ablagerung von Feststoffen auf den Wärmetauscher- Flächen von Verdampfern ist ein gravierendes Problem und verursacht große Kosten. Der in Patentanspruch 1 angegebenen Erfindung liegt das Problem zugrunde, die Foulingwiderstände des Fallfilmverdampfers während des Produktionsprozesses nahezu auf null zu halten. Dieses Problem wird durch das im Patentanspruch 1 aufgeführte, on line arbeitende automatische Reinigungssystem mit dem ihm angepassten Wärmetauscher gelöst. Der mit der Erfindung erzielte Vorteil besteht insbesondere darin, daß die Wärmetau¬ scher-Flächen des Verdampfers ständig gereinigt werden können, ohne den Produktions¬ prozeß zu unterbrechen und so die Foulingwiderstände beliebig gering gehalten werden können.It is known that technical falling film evaporators usually consist of a bundle of vertical tubes, on the inside of which a boiling liquid film flows down under the influence of gravity. Deposition of solids on the heat exchanger surfaces of evaporators is a serious problem and causes great costs. The invention specified in claim 1 is based on the problem of keeping the fouling resistances of the falling film evaporator almost at zero during the production process. This problem is solved by the on-line automatic cleaning system listed in claim 1 with the heat exchanger adapted to it. The advantage achieved by the invention is in particular that the heat exchanger surfaces of the evaporator can be cleaned continuously without interrupting the production process and the fouling resistances can thus be kept as low as desired.
Die Erfindung, die hauptsächlich aus drei verschiedenen Baugruppen (Produktvertei- lungssystem, Wärmetauscher und automatisches Reinigungssystem) besteht, hat zwei Ausführungsbeispiele, die im folgenden beschrieben werden.The invention, which mainly consists of three different assemblies (product distribution system, heat exchanger and automatic cleaning system), has two exemplary embodiments, which are described below.
1. Erstes Ausführungsbeispiel1. First embodiment
Das erste Ausführungsbeispiel ist in Abb.la und Abb.lb dargestellt.The first embodiment is shown in Fig.la and Fig.lb.
Das Produktverteilungssystem ist als flacher, rechteckiger Behälter, dessen beide Enden geschlossen sind, ausgeführt. Am unteren Boden sind Flachstrahldüsen (7 in Abb. la) in Reihen angeordnet, deren Anzahl gleich der Anzahl der Verdampferkammern ist (10 in Abb.la). Die Mittellinien der Reihen befinden sich in den Symmetrieebenen der zugehörigen Verdampferkammern. Die Düsen in einer Reihe haben einen Abstand von 35 - 45 mm und sprühen in der vertikalen Richtung abwechselnd nach zwei Seiten der Verdampferkammer mit einem Neigungswinkel von etwa 20°. Die Form des mit der Flachstrahldüse erzeugten Sprühnebels ist flach und fächerförmig mit einem Nebelkegelwinkel von etwa 110°. Die gesprühte Menge ist abhängig von dem Typ der Düse, dem Druck im Produktverteilungssystem und den physikalischen Eigenschaften des Produktes. Die Massenverteilung des Sprühnebels einer Düse quer zu der Sprüh¬ kegel-Hauptachse entspricht näherungsweise einer Normal Verteilung. Der Neigungwinkel der Düsen (ca. 20°), der Sprühnebel-Kegel winkel (110°), der Abstand zwischen zwei benachbarten Düsen und der Abstand zwischen Düsen und Verdampferkammer-Oberflä- chen sind so aufeinander abgestimmt, daß mindestens eine zwanzigprozentige Überlagerung der Sprühnebel von zwei benachbarten und in die gleiche Richtung arbeitenden Düsen gewährleistet ist. Dies führt zu einer gleichmäßigen Verteilung der Flüssigkeit auf den Wänden der Verdampferkammern. Das Verteilungssystem bietet den Vorteil, daß der dadurch erzeugte Fallfilm eine hohe Anfangsgeschwindigkeit besitzt. Der Wärmetauscher mit einer rechteckiger äußerer Form besteht aus einer Reihe schmaler, rechteckiger Kammern und hat dampfseitig eine mit Platten berippte Oberfläche. Am oberen Ende des Wärmetauschers, wo die Sprühnebel auf die Wärmetauscher-Flächen auftreffen, ist die Verteilung der Flüssigkeit sehr ungleichmäßig, so daß hier eine erhöhte Fouling-Gefahr besteht. Um Fouling-Prozesse möglichst zu unterbinden, ist in diesem Gebiet eine ca. 0.1m hohe Kühlzone (8 in Abb.la) angeordnet, die es ermöglicht diesen Teil des Wärmetauschers zu kühlen. Das automatische Reinigungssystem besteht aus Reinigungsbürsten (16 in Abb. lb), Bürstenköpfen (18 in Abb. lb), Verteilbürsten (19 in Abb. lb), Antriebsstangen (3 in Abb. la), Verteilerrohren (2 in Abb. la), dem Produktzulauf (1 in Abb. la), einem Spindelantrieb (12 in Abb.la) und Zahnradgetriebesystem (14 in Abb.la) mit Motor und Regelungssystem (13 in Abb.la). Jede Antriebsstange ist gegen den Boden des Wärmetauschers mit einer Gummidichtung abgedichtet. Jeder Verdampfkammer ist eine der Breite und Länge der Kammer angepasste Bürste, die auf einen Bürstenkopf montiert wird, zugeordnet. Die Bürstenköpfe werden durch jeweils zwei auf den beiden Verteilerrohhren montierte Antriebsstangen gestützt. Alle Bürstenköpfe, Antriebsstangen und Verteilerrohe sind hohl. An den Längsseiten der Bürstenköpfe sind Löcher mit ca. 3mm Durchmesser angebracht (17 in Abb.lb). Der Abstand zwischen zwei benachbarten Löchern beträgt ca.15mm. Das während der Reinigungsphase eingepumpte flüssige Produkt kann durch Produktzulauf, Verteilerrohre, Antriebsstangen, Bürstenköpfe und durch die kleinen Löcher austreten. Alle Bürsten, Bürstenköpfe, Antriebsstangen und die zwei Verteilerrohre bilden einen starren Körper, der mittels Motor, Zahnradgetriebe und Spindelantrieb während des Betriebes in frei wählbaren Zeitintervallen auf und ab bewegt wird. Ein Reinigungszyklus dauert ca.30 Sekunden. Danach bleiben die Bürsten bis zum nächsten Reinigungszyklus an ihrer Ruheposition am Boden des Verdampfers (S-S in Abb. la). Um das Entstehen von trockenen Flächen, wie sie bei der Aufwärtsbewegung der Bürsten entstehen, zu vermeiden, werden die folgenden Maßnahmen getroffen: a) Die Reinigungsbürsten sind so gestaltet, daß zwischen den Borsten dreieckigeThe product distribution system is designed as a flat, rectangular container with both ends closed. At the bottom bottom, flat jet nozzles (7 in Fig. La) are arranged in rows, the number of which is equal to the number of evaporator chambers (10 in Fig.la). The center lines of the rows are in the planes of symmetry of the associated evaporator chambers. The nozzles in a row are at a distance of 35-45 mm and alternately spray in the vertical direction on two sides of the evaporator chamber with an inclination angle of approximately 20 °. The shape of the spray generated with the flat jet nozzle is flat and fan-shaped with a mist cone angle of approximately 110 °. The amount sprayed depends on the type of nozzle, the pressure in the product distribution system and the physical properties of the product. The mass distribution of the spray mist of a nozzle transversely to the main spray cone axis corresponds approximately to a normal distribution. The angle of inclination of the nozzles (approx. 20 °), the spray cone angle (110 °), the distance between two neighboring nozzles and the distance between the nozzles and the evaporator chamber surfaces are matched to one another in such a way that at least a 20 percent overlap of the spray fog is guaranteed by two neighboring nozzles working in the same direction. This leads to an even distribution of the liquid on the walls of the evaporator chambers. The distribution system has the advantage that the falling film produced thereby has a high initial speed. The heat exchanger with a rectangular outer shape consists of a series of narrow, rectangular chambers and has a surface with ribbed plates on the steam side. At the upper end of the heat exchanger, where the spray mist hits the heat exchanger surfaces, the distribution of the liquid is very uneven, so that there is an increased risk of fouling here. In order to prevent fouling processes as much as possible, an approximately 0.1m high cooling zone (8 in Fig.la) is arranged in this area, which makes it possible to cool this part of the heat exchanger. The automatic cleaning system consists of cleaning brushes (16 in Fig. Lb), brush heads (18 in Fig. Lb), distribution brushes (19 in Fig. Lb), drive rods (3 in Fig. La), distributor pipes (2 in Fig. La), the product inlet (1 in Fig. la), a spindle drive (12 in Fig.la) and gear transmission system (14 in Fig.la) with motor and control system (13 in Fig.la). Each drive rod is sealed against the bottom of the heat exchanger with a rubber seal. Each evaporation chamber is assigned a brush which is adapted to the width and length of the chamber and which is mounted on a brush head. The brush heads are supported by two drive rods mounted on the two distributor pipes. All brush heads, drive rods and distributor pipes are hollow. Holes with a diameter of approx. 3 mm are made on the long sides of the brush heads (17 in Fig.lb). The distance between two neighboring holes is approx.15mm. The liquid product pumped in during the cleaning phase can escape through the product inlet, distribution pipes, drive rods, brush heads and through the small holes. All brushes, brush heads, drive rods and the two distribution pipes form a rigid body that moves up and down during operation in freely selectable time intervals by means of a motor, gear mechanism and spindle drive becomes. A cleaning cycle takes about 30 seconds. The brushes then remain in their resting position on the bottom of the evaporator until the next cleaning cycle (SS in Fig. La). In order to avoid the formation of dry surfaces, such as occur when the brushes move upwards, the following measures are taken: a) The cleaning brushes are designed so that triangular between the bristles
Produktdurchtrittsöffnungen entstehen (15 in Abb.lb), so daß die von den aufwärts bewegten Bürsten gesammelte Flüssigkeit nach unten abfließen kann. b) Wenn sich die Bürstenaufwärts bewegen, wird automatisch ein Ventil geöffnet und ein Teil des flüssigen Produktes fließt durch den Produktzulauf, die Verteilerrohre und die Antriebsstangen in die Bürstenköpfe, wo es durch die seitlich angeordneten Löcher austritt und die Wärmetauscher-Flächen benetzt. c) Unterhalb der Löcher ist an jedem Bürstenkopf eine weitere, weiche Verteilbürste installiert, die das flüssige Produkt gleichmäßig auf den Oberflächen verteilt.Product through openings are created (15 in Fig.lb) so that the liquid collected by the brushes moving upwards can flow downwards. b) When the brushes move upwards, a valve is automatically opened and part of the liquid product flows through the product inlet, the distributor pipes and the drive rods into the brush heads, where it exits through the holes on the side and wets the heat exchanger surfaces. c) Below the holes, another soft distribution brush is installed on each brush head, which distributes the liquid product evenly on the surfaces.
Wenn der durch das Düsenverteilungssystem produzierte Flüssigkeitsfilm eine höhere Fallgeschwindigkeit als die Geschwindigkeit der sich abwärts bewegenden Bürsten besitzt, entstehen bei der Abwärtsbewegung der Bürsten keine trockenen Flächen.If the liquid film produced by the nozzle distribution system has a falling speed higher than the speed of the downward moving brushes, no dry surfaces are created when the brushes move downward.
2. Zweites Ausführungsbeispiel2. Second embodiment
Das zweite Ausführungsbeispiel ist in Abb.2 und Abb.3 dargestellt.The second embodiment is shown in Fig.2 and Fig.3.
Das Produktverteilungssystem besteht aus Verteilplatte (8 in Abb.2) und Verteilungs¬ rohren (9 in Abb.2). Die durch die Verteilplatte getrennten Räume sind durch zwei Rohre (7 in Abb.2) miteinander verbunden. In den unteren Raum ragen die Wände der Verdampferkammer. Am oberen Rand der Wände der Verdampferkammer sind V-förmi- ge Aussparungen angeordnet (vgl. Einzelheit Y in Abb.3). Das flüssige Produkt fließt über die Verteilplatte durch die Verteilungsrohre auf das obere Ende des Wärme¬ tauschers. Es wird durch die V-förmigen Aussparungen gleichmäßig an dem oberen Ende der Verdampferkammer verteilt und fließt unter dem Einfluß der Schwerkraft in einem dünnen Film nach unten. Der Wärmetauscher hat eine rechteckige äußere Form. Seine Verdampferkammer besteht aus einer Reihe schmaler, rechteckiger und senkrechter Kammerelemente, die in ihrer Mitte durch eine schmale, orthogonale Kammer verbunden sind (vgl. Schnitt I - L in Abb.2). Die Verdampferkammer ist von beidseitig gewellten Platten begrenzt und dampfseitig von Nadeln oder gebohrten Platten berippte, so daß zum einen die Stabilität der Verdampferkammerswände erhöht wird und zum anderen der Wärmedurchgangs¬ koeffizient verbessert wird. Es ist möglich, der Hauptteil des Wärmetauschers durch Löten im Salzbad herzustellen. Das automatische Reinigungssystem besteht aus Reinigungsbürsten (11 in Abb.2), einem Bürstenkopf (12 in Abb.2), Verteilbürsten (13 in Abb.2), zwei Antriebstangen (6 in Abb.2), einer Querstange (4 in Abb.2), einem Spindelantrieb (3 in Abb.2) und Zahnradgetriebesystem (1 in Abb.2) mit Motor und Regelungssystem (2 in Abb.2). Die zwei Antriebstangen sind gegen den Verdampferdeckel mit einer Gummidichtung abgedichtet. Der Bürstenkopf, der durch die zwei auf die Querstange montierten Antriebstangen gestützt wird, hat die gleiche Form wie die Verdampferkammer (vgl. Abb.4). Jedem Verdampferkammerelement sind zwei Reinigungsbürsten (vgl. Abb.5) und Verteilbürsten, die jeweils auf der Ober- und Unterseite des Bürstenkopfs montiert wird, zugeordnet. Alle Bürsten, der Bürstenkopf, die Querstange und die zwei Antriebs¬ stangen bilden einen starren Körper, der mittels Motor, Zahnradgetriebe und Spindelantrieb während des Betriebes in frei wählbaren Zeitintervallen ab und auf bewegt wird, um alle Wärmetauscher-Flächen zwei mal zu reinigen. Die Reinigungsbürsten bewegen sich zwischen Positionen S-S und E-E in Abb.2. Ein Reinigungszyklus dauert ca.30 Sekunden. Danach bleiben die Bürsten bis zum nächsten Reinigungszyklus an ihrer Ruheposition, die sich in dem Verdampferdeckel zwischen den Verteilungsrohren befindet (Position S-S in Abb.2). An zwei gegenüberliegenden Wänden des Verdampfer¬ deckels und des Verdampferbodens sind die in Größe, Anzahl und Position an die Verdampferkammerelemente angepassten Führungsnuten (5 und 15 in Abb.2), die die problemlose Bewegung der Reinigungsbürsten bei ihre Ein- und Austritt aus der Verdampferkammer gewährleisten, angeordnet.The product distribution system consists of a distribution plate (8 in Fig.2) and distribution pipes (9 in Fig.2). The rooms separated by the distribution plate are connected to each other by two pipes (7 in Fig.2). The walls of the evaporator chamber protrude into the lower room. V-shaped recesses are arranged on the upper edge of the walls of the evaporator chamber (see detail Y in Fig. 3). The liquid product flows through the distribution plate through the distribution pipes to the upper end of the heat exchanger. It is evenly distributed through the V-shaped recesses at the upper end of the evaporator chamber and flows down in a thin film under the influence of gravity. The heat exchanger has a rectangular outer shape. Its evaporator chamber consists of a series of narrow, rectangular and vertical chamber elements, which are connected in the middle by a narrow, orthogonal chamber (see section I - L in Fig.2). The evaporator chamber is delimited by corrugated plates on both sides and ribbed on the steam side by needles or drilled plates, so that on the one hand the stability of the evaporator chamber walls is increased and on the other hand the heat transfer coefficient is improved. It is possible to manufacture the main part of the heat exchanger by soldering in a salt bath. The automatic cleaning system consists of cleaning brushes (11 in Fig.2), a brush head (12 in Fig.2), distribution brushes (13 in Fig.2), two drive rods (6 in Fig.2), a crossbar (4 in Fig. 2), a spindle drive (3 in Fig.2) and gear transmission system (1 in Fig.2) with motor and control system (2 in Fig.2). The two drive rods are sealed against the evaporator cover with a rubber seal. The brush head, which is supported by the two drive rods mounted on the crossbar, has the same shape as the evaporator chamber (see Fig. 4). Two cleaning brushes (see Fig. 5) and distribution brushes, which are mounted on the top and bottom of the brush head, are assigned to each evaporator chamber element. All brushes, the brush head, the crossbar and the two drive rods form a rigid body, which is moved occasionally by the motor, gear mechanism and spindle drive during operation at freely selectable time intervals in order to clean all heat exchanger surfaces twice. The cleaning brushes move between positions SS and EE in Fig.2. A cleaning cycle takes about 30 seconds. The brushes then remain in their rest position until the next cleaning cycle, which is located in the evaporator cover between the distribution pipes (position SS in Fig. 2). On two opposite walls of the evaporator cover and the evaporator bottom are the guide grooves (5 and 15 in Fig. 2), which are adapted in size, number and position to the evaporator chamber elements, and which ensure the problem-free movement of the cleaning brushes as they enter and exit the evaporator chamber , arranged.
Unterhalb der Ruheposition sind die Reinigungsplatten (10 in Abb.2) an die Verteilungs¬ rohre geschweißt. Jeder Reinigungsbürste sind jeweils zwei Platten zugeordnet. Die Länge der Platte und der Abstand zwischen diesen zwei Platten passt an die Bürste- geometrie an. Auf den konvexen Arbeitsoberflächen der Reinigungsplatten sind etwa 2mm lange, kegelförmige Dornen angeordnet (vgl. Einzelheit Y in Abb.3). Dadurch werden die Reinigungsbürsten bei der Ab- und Aufbewegung des Reinigungssystems teilweise mechanisch entfeuchtet und gereinigt.Below the rest position, the cleaning plates (10 in Fig. 2) are welded to the distribution pipes. Two cleaning plates are assigned to each cleaning brush. The length of the plate and the distance between these two plates adapt to the brush geometry. About 2mm long, conical spikes are arranged on the convex working surfaces of the cleaning plates (see detail Y in Fig.3). As a result, the cleaning brushes move as the cleaning system moves up and down partly mechanically dehumidified and cleaned.
Um das Entstehen von trockenen Flächen, wie sie bei der Aufwärtsbewegung derTo prevent the emergence of dry surfaces, such as the upward movement of the
Bürsten entstehen, zu vermeiden, werden die folgenden Maßnahmen getroffen: a) In der Mitte der Reinigungsbürsten sind ca.10mm breite Schlitze (vgl. Abb.5) und zwischen den Reinigungsbürsten und dem Bürstenkopf sind Schlitze von 10mm Höhe angeordnet. Durch diese Schlitze kann der abwärtsfließende Produktfilm bei der Aufwärtsbewegung der Bürsten nach unten abfließen. b) Unterhalb des Reinigungskopfs sind weiche Verteilbürsten (13 in Abb.2) angeordnet, die das durch die Schlitze abfließende Produkt gleichmäßig auf die Wände der Verdampferkammer verteilen.To avoid brushes, the following measures are taken: a) In the middle of the cleaning brush there are approx.10mm wide slots (see Fig.5) and between the cleaning brushes and the brush head there are 10mm high slots. Through these slots, the downward flowing product film can flow downward as the brushes move upward. b) Soft distribution brushes (13 in Fig.2) are arranged below the cleaning head, which distribute the product flowing through the slots evenly over the walls of the evaporator chamber.
Wenn die Geschwindigkeit des Reinigungssystem bei der Abwärtsbewegung größer als die Fließgeschwindigkeit des Produktfilms ist, entstehen trockene Flächen. Deswegen wird die Geschwindigkeit der abwärtsbewegenden Reinigungsbürsten bei ca.0.5m hochem oberem Gebiet der Verdampfkammer niedrig eingestellt, um die Entstehung der trockenen Flächen zu minimieren oder zu vermeiden.If the speed of the cleaning system during the downward movement is greater than the flow speed of the product film, dry surfaces are created. For this reason, the speed of the cleaning brushes moving downwards is set low at approx.0.5m high upper area of the evaporation chamber in order to minimize or avoid the formation of dry surfaces.
Während des Reinigungsprozesses wird die Verdampferkammer durch die Reinigungs¬ bürsten in zwei Räume getrennt, die durch Bohrungen (14 in Abb.2) miteinander verbunden sind, um auftretende Druckdifferenzen zu minimieren.During the cleaning process, the evaporator chamber is separated into two rooms by the cleaning brushes, which are connected to one another by bores (14 in Fig. 2) in order to minimize pressure differences that occur.
Bei zwei Ausführungsbeispielenkönnen alle Wärmetauscher-Flächen durch die getaktete Ab- und Aufbewegung des automatischen Reinigungssystems ohne Unterbrechung des Produktionsprozesses on line gereinigt werden, und damit die Foulingwiderstände nahezu auf null gehalten werden. In two exemplary embodiments, all of the heat exchanger surfaces can be cleaned online by the clocked movement of the automatic cleaning system without interrupting the production process, and the fouling resistances can thus be kept to almost zero.

Claims

Patentansprüche Claims
1. Fallfilmverdampfer mit automatischem Reinigungssystem zum Einsatz in der chemi¬ schen- und/oder der Lebensmittelindustrie, bestehend aus einem Produktverteilungs¬ system, einem Wärmetauscher und einem Reinigungssystem, bei dem der Wärmetau- scher-Flächen mit Bürsten zu reinigen ist, die entlang der Wärmetauscher-Flächen bewegbar sind, dadurch gekennzeichnet, daß die Bürsten vor und/oder nach der Rei¬ nigung in einer Ruheposition angeordnet sind, die außerhalb des Wärmetauschers ist.1. Falling film evaporator with automatic cleaning system for use in the chemical and / or food industry, consisting of a product distribution system, a heat exchanger and a cleaning system in which the heat exchanger surfaces are to be cleaned with brushes that run along the Heat exchanger surfaces can be moved, characterized in that the brushes are arranged before and / or after the cleaning in a rest position which is outside the heat exchanger.
2. Fallfilmverdampfer gemäß Anspruch 1, dadurch gekennzeichnet, daß die Bürsten an den Enden von Schubstangen angeordnet sind. 2. Falling film evaporator according to claim 1, characterized in that the brushes are arranged at the ends of push rods.
3. Fallfilmverdampfer gemäß Anspruch 1. dadurch gekennzeichnet, daß das Reinigungs¬ system härtere Reinigungsbürsten und weichere Verteilbürsten enthält.3. Falling film evaporator according to claim 1, characterized in that the cleaning system contains harder cleaning brushes and softer distribution brushes.
4. Fallfilm Verdampfer gemäß Anspruch 1, dadurch gekennzeichnet, daß die Reini¬ gungsbewegung der Bürsten über Spindelantrieb erfolgt.4. Falling film evaporator according to claim 1, characterized in that the cleaning movement of the brushes takes place via a spindle drive.
5. Fallfilmverdampfer gemäß Anspruch 2 und 4, dadurch gekennzeichnet, daß die Schubstangen durch mit Dichtungen versehene Öffnungen aus dem Verdampfer austreten und das Spindelantrieb außerhalb angeordnet ist. 5. Falling film evaporator according to claim 2 and 4, characterized in that the push rods emerge from the evaporator through openings provided with seals and the spindle drive is arranged outside.
PCT/DE1994/000938 1993-08-19 1994-08-17 Falling film evaporator with an automatic cleaning system WO1995005227A1 (en)

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DE4327839A DE4327839A1 (en) 1993-08-19 1993-08-19 Nozzle falling film evaporator with automatic cleaning system
DEP4327839.6 1993-08-19

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DE202012005542U1 (en) 2012-06-07 2012-06-26 Johannes Rainer Device for cleaning the outer surfaces of heat exchangers
US9568253B2 (en) 2011-04-18 2017-02-14 Empire Technology Development Llc Dissipation utilizing flow of refrigerant
US10010811B2 (en) 2013-05-28 2018-07-03 Empire Technology Development Llc Evaporation-condensation systems and methods for their manufacture and use
US10065130B2 (en) 2013-05-28 2018-09-04 Empire Technology Development Llc Thin film systems and methods for using same

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FR2775767B1 (en) * 1998-03-06 2000-06-02 Packinox Sa DEVICE FOR CLEANING A CIRCULATION CHANNEL OF A THERMAL EXCHANGE FLUID IN A PLATE HEAT EXCHANGER
CN100455972C (en) * 2007-01-17 2009-01-28 哈尔滨工业大学 Online pollution repellent, heat exchanger equipment and method for tube cluster of cold and heat sources from sewage and surface water
DE102008040006A1 (en) * 2008-08-27 2010-03-04 Qvf Engineering Gmbh Evaporating device for evaporating liquid in reactor, has side wall, base wall and heating device for heating side wall, where liquid distributing device has pumping circuit for pumping liquid contained in reactor
CN114669066B (en) * 2022-03-24 2023-09-26 四川点石能源股份有限公司 MVR evaporation concentration system

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DE935339C (en) * 1953-11-17 1955-11-17 Walter Hartwig Device for cleaning the inner walls of pipes in vertical pipe systems
DE1619697A1 (en) * 1967-05-31 1971-07-08 Bayer Ag Falling film evaporator
DE2948387A1 (en) * 1979-12-01 1981-06-04 Crombeen, Alfonsus Franciscus, 6000 Frankfurt Cleaning tube nest containing heat exchangers - uses brushes which are mechanically moved through tubes during operation
DE3644629A1 (en) * 1986-12-29 1988-07-07 Reininger Gmbh Vertical flow-heat distributor with heat recovery and harmful-substance reduction

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DE935339C (en) * 1953-11-17 1955-11-17 Walter Hartwig Device for cleaning the inner walls of pipes in vertical pipe systems
DE1619697A1 (en) * 1967-05-31 1971-07-08 Bayer Ag Falling film evaporator
DE2948387A1 (en) * 1979-12-01 1981-06-04 Crombeen, Alfonsus Franciscus, 6000 Frankfurt Cleaning tube nest containing heat exchangers - uses brushes which are mechanically moved through tubes during operation
DE3644629A1 (en) * 1986-12-29 1988-07-07 Reininger Gmbh Vertical flow-heat distributor with heat recovery and harmful-substance reduction

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9568253B2 (en) 2011-04-18 2017-02-14 Empire Technology Development Llc Dissipation utilizing flow of refrigerant
DE202012005542U1 (en) 2012-06-07 2012-06-26 Johannes Rainer Device for cleaning the outer surfaces of heat exchangers
US10010811B2 (en) 2013-05-28 2018-07-03 Empire Technology Development Llc Evaporation-condensation systems and methods for their manufacture and use
US10065130B2 (en) 2013-05-28 2018-09-04 Empire Technology Development Llc Thin film systems and methods for using same

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