DD207642A3 - SELF-CLEANING HEAT TRANSFER PIPE - Google Patents

Abstract

The invention relates to a universally applicable self-cleaning heat transfer tube with a cylindrical cross section, which is traversed by fluid media. The aim is to create a no or only limited polluting heat transfer tube with improved internal heat transfer conditions, thus increasing the efficiency and reliability of heat transfer. The invention has the object to provide a correspondingly expedient embodiment of heat transfer tubes and is thereby solved that a known helical or schneckenfoermig formed element that is rotatably mounted in the interior of a pipe by means of a holding device at the inlet end of the tube from single, each other connected and at least limited to each other tiltable members whose edge zones are turned away from the direction of rotation exists. The invention can be applied in heat transfer media, in particular the chemical and brine industry.

Description

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Self-cleaning heat exchanger tube. _;

Anwe_ndungs_g £ bi ^ et_der_Erfi_ndung

The invention relates to a self-cleaning heat exchanger tube with a cylindrical cross-section, which is traversed by fluid media and in particular e.insetzbar for heat exchangers of the chemical and SoIe industry.

According to US Pat. No. 4,174,750, a self-cleaning heat exchanger tube with a spiral-shaped installation is known, which is rotatably mounted on one side on the side of the media inlet by means of a composite part. This device is proposed for. Use in heat exchangers to prevent dirt layer deposits on the pipe inner wall and improve the internal heat transfer conditions. · '-

The disadvantage of the solutions mentioned is that their use, in particular for pipe lengths greater than 2 m, as they are used in industry, 'is problematic. This can be explained by the high demands on the straightness of the helical installation, which can hardly be realized in industrial production, and which corresponded to it

The longer the Rohre- used are, the more 'in · Folge.schwerkraftbedingter deflection or deflection as a result of process-related thermal> stresses the danger of Abweiches from this requirement. Such influences are exposed to the vast number of tubular heat exchanger, which leads to jamming of the installation inside the pipe and is still favored by the sharp-edged wheels .. 'It is conceivable, even larger lengths of pipe with a rotatably mounted spiral installation aus-. prepare, if one manufactures this from a sufficiently flexible plastic material. The disadvantage, however, is that due to increased friction between the pipe wall and installation required for the rotational movement

Impulse and thus the flow rate of the medium must be very high. Under these circumstances, however, wall shear stress and turbulence can be sufficiently great to prevent overgrowth. Prevent dirt layer. In addition, with increasing signs of wear of the installation is expected.-Further limited. the field of application of plastic materials to relatively low temperature ranges, during which problems of contamination, in particular at high temperatures, occur more frequently.

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^ iel_der_Erfindung

The object of the invention is to provide a universally applicable self-cleaning heat exchanger tube, which increases the performance and reliability of the apparatus and avoids the shortcoming of the characterizing prior art. ,. '

The object of the invention lies in the expedient embodiment of a heat transfer medium through which fluid media flows, in the interior of which the heat transfer reducing dirt layer builds up. to prevent or to limit to a technically inconsequential extent and is significantly improved by increased boundary layer turbulence at a relatively low pressure drop increase in heat transfer.

The object is achieved in that a per se known, helical or helical 'formed element which is rotatably mounted in a tubular body on one side, from .einzelnen interconnected ¹ and at least limited to each other tiltable members whose edge zones are turned away from the direction of rotation, consists. These elements can be formed both from links of the same direction of rotation as well as alternately from left and right-hand links. . · '..'

f) Additional information 1 -

The invention will be explained in more detail using an exemplary embodiment. It shows:

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Figure 1: longitudinal section through the heat exchanger tube

'. with built-in Rotationslement, consisting

from links of equal mobility

Figure 2: top view of the heat exchanger tube

Figure 3: sectional view of the bearing member in two

'Views -' ..

FIG. 4: Illustration of the swivel angle oC

The self-cleaning heat exchanger tube (Fig. 1) is composed essentially of five parts: The tubular body T, preferably helical members 2 of the element, the holding device 4 and the position member 3 of the element at the entrance end of the tubular body 1 and the connecting members 5 of the individual members 2 with each other. , , , , _

The bearing 3 * (Fig. 1, Fig. 3) was shown in the form of a ball joint; but there are also other rotational movement permitting embodiments possible

The element consists of gleichgängigen, helical members 2, which are not unrestricted radially rotatable from each other. As'Verbindungsorgä'ne 5 simple Drahtöse ^ were selected. In order to prevent jamming of the element in the tubular body 1 'and thus to ensure trouble-free operation, the individual elements 2 must be connected to each other in such a way that they are at least an angle cC = 2 (ie dp,. ) / "- ,. ^ n are mutually pivotable (Fig. 4). Furthermore, it is necessary that the edges of the members 2 are turned away to the direction of rotation, which is preferably achieved by inde _v m whose cross-section "S ^ -shaped.

Another advantage is that the edges of the links 2 slide during their rotation on a fluid film, which significantly increases the life of the device:. ^. -.

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This design corresponds to the simplest construction and should be used for processes with a sufficiently high flow impulse of the fluid. Of course, connecting members 5 in the form of ball joints or the like are also possible. Such a design would continue to allow the rotational movement of the others in the event of a possible standstill of one or more members 2.

With decreasing momentum, the pitch should be reduced, if this is no longer possible, should the more complicated variants with double "S" cross-shaped helical cross-section ¹ and opposing links 2, to the rotation of the member 2 opposite to the rotation of the fluid flow for rotation take advantage of the subsequent member 2, be resorted to.

The length and radial extent of the links 2 is primarily dependent on their manufacturing tolerances, the tolerances of the tubular body inner diameter and its straightness. Growing lengths of the links 2 therefore generally require increasing gap widths between the link and tube body inner diameters. Preferably, the lengths of the individual members 2 should have the fifth to fifteenth value and their largest radial extent Cd ₁ ···) the 0.85th to 0.95th part of the tube body inner diameter.

The material combination between pipe body 1 and element. depends on the process parameters and the chemical and physical properties of the used. Fluid. Thus, for example, elements made of plastic or glass can be used in box-coated tubes and for particularly corrosive media in the lower temperature range, and ceramic materials can also be used for higher temperatures. Stainless steel is suitable for non-rusting media. Non-ferrous metal elements ^:

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. prove for "a large part of the occurring cases of use as advantageous.

The holding device 4 (Fig. 1, Fig. 2) of the element is designed as a slightly conical bush to create a frictional, releasable connection with the tubular body 1. This allows, if necessary, easy replacement of the elements, for example, to adapt to changed operating conditions.

The solution according to the invention works as follows:

If the self-cleaning Wärmeübertragerrohr flows through a fluid with a sufficiently high flow impulse,. wherein the medium entry is on the side of the holding device 4, so learn the Glie-. The 2 of the 'element an angular momentum and are put into' rotary motion. The "S" shaped helical transverse effect causes the links 2 to always slide on a thin fluid cushion during rotation, resulting in high boundary layer turbulence and thus. Improvement of heat transfer leads. The accumulation of dirt and -abtragung takes place in this self j reinigenden'Wärmeübertragerrohr quasi simultaneously and die.maximale, dirt layer thickness reaches its asymptotic value at very low levels. This is ensured by the sweeping the pipe inner wall by means of the helical edges of the rotating members 2. With each rotation of the links 2 is carried · "a Pseudoberühru-ng each of the Rohri'nnenwand bilden-; the surface element ^1,.

/ In any case, it is process technology favorable; to aim for high rotatory behavior of links 2.

The advantages of the invention are:. , , •1 . 'Materialedavigation by the possibility of a-r, evenly high' .Werrerubertraguiigsleistung, so that the apparatuses can be made smaller. , '

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2. Operating cost savings by eliminating operating. Interruptions and process parameter changes.

modifications for pipe cleaning. ·

3. High operational reliability, even in case of failure of some or even all elements due to the better Versehmutzungsverhaltens and better heat transfer conditions, compared.zum conventional empty pipe. , '.

4. Favorable possibility of element change (for example, to adapt to changed operating conditions). '_

Claims (4)

237028 4 , Self-cleaning heat exchanger tube with cylindrical cross-section, which contains a helically or helically shaped, over-the entire tube length 'continuously extending element containing the I, Media entry of the tubular body by means of a holding device and a bearing member on one side rotatably - '' ^ is fixed, characterized in that the element 'of individual, interconnected members (2) whose.Randzonen are turned away to the direction of rotation, and'homogen from limbs (2) the same direction or alternately from left and right-handed links (2) is constructed. 2. Self-cleaning heat exchanger tube according to item 1-, characterized in that the individual members (2) of the element have a length of 2 to 50 times the tubular body inner diameter ¹ . -. ' 3.- self-cleaning heat exchanger tube according to item 1, characterized in that the largest radial extent of the element, the 0.7th to O, 98th part of the tubular body inner diameter d. is. \ 4. Self-cleaning heat exchanger tube according to item 1, characterized in that the ends of the age-. nierend left and right-hand members (2) of the element punctiform at their axes of rotation ver -.- bound or stored and arranged radially to each other unrestricted rotatably and the members (.2) with respect to the axis of rotation at least to the :., -., ·. "Angle cL = 2 (d. - d ^.) / 1 _αι (d.) - inner diameter of the pipe, d. _p , ^: . __ , - largest radial.; extension of the member (2); I _- ^ -, ^ - length 'of the individual members (2) of the element.) in all 'the. pipe axis 2370 28 4 including levels pivotally, but are not provided axially displaceable depending on the forces occurring. ¹ Self-cleaning heat exchanger tube according to item 1, characterized in that the pitch (h) of the elements (2) of the element as a function of the mass flow rate and the flow velocity. is executed and. with increasing pulse of the current. increasing medium increases. _s . ' Self-cleaning heat exchanger tube according to item 1 ,. characterized in that the tubular body (1) as well as the element of steel, non-ferrous metals, plastic, glass or ceramic materials or combinations thereof may exist. For this 1 page drawings