JPH0523932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention provides a method for manufacturing heat and/or mass exchangers including tubes in a thermoplastic mold using an injection mold consisting of at least two parts, for example an upper mold and a lower mold. It relates to a method of manufacturing by injection molding of materials.

PRIOR ART From DE 28 24 934 A1, a method and a device for manufacturing a mass exchanger are known, in which a hollow fiber bundle is placed in a casting mold and a thermoplastic material molten therein is placed. inject. After solidification of the thermoplastic material, the fiber bundle is removed from the mold and cut at the solidified thermoplastic material. Two tube bases are thus created. If the tube base is integrally connected at both ends of the hollow fiber bundle, a mass exchanger is obtained which is still fitted with only the necessary connecting elements and is optionally placed in a housing. This patent application also states that experiments have already been carried out to obtain a tube base by pressure impregnating each end of a pre-cut hollow fiber bundle with a polymer composition. . However, this pressure impregnation has the disadvantage that the very thin walls of the hollow fibers are destroyed or crushed and the open fiber ends tend to become clogged.

A similar method is known from DE 30 27 087 A1, in which several tubes are provided with a tube base by injection molding.
A protrusion is introduced into the tube for injection molding. However, this method can only be applied advantageously if the tube exists in only one plane after injection molding, and the strength of the bond between the tube and the tube base is only as good as that obtained using the adhesive compound. I almost can't get over it. This known method is extremely expensive if the tubes are required to be arranged in several planes after injection molding. This method can often no longer be applied at all with regard to the desired position of the tube.

Furthermore, it is known from European Patent Application No. 22 234 to glue a metal tube and a tube base, in which case the metal tube is first inserted into the tube base and then the tube base is coated with adhesive from the outside. To improve adhesive adhesion, the adhesive may be exposed to increased pressure after coating. Furthermore, the metal tubes are interconnected via a number of thin layers between the two tube bases. In the case of compounds of this type, a large number of working steps are required and the curing of the adhesive is extremely time consuming. Coating the tube base with adhesive also takes longer and requires more care the more tubes are inserted into the tube base.

Problem to be Solved by the Invention It is an object of the invention to avoid the above-mentioned disadvantages and to provide a heat and/or mass exchanger comprising tubes, which consists of at least two parts, for example an upper mold and a lower mold, and which is particularly thin-walled. and/or for injection molding of thermoplastic materials using injection molds which are suitable for inserting easily deformable tubes and which ensure a sufficient connection between the tube and the tube base. Therefore, it is an object of the present invention to provide a manufacturing method.

Means for Solving the Problems The above problem is such that the first part (upper mold or lower mold) of the injection mold is made of plastic and can be connected to the tubes by fusion, and for each tube. An insert having a base with a through hole is arranged as a positioning element of the tube in such a way that the insert is arranged at least partially in a mating manner in the first part of the injection mold. inserted into;
Said tubes are inserted into each hole of the insert; a pin is inserted into each tube, and then the injection mold is inserted so that the pins are frictionally coupled ( molten thermoplastic material is passed through an injection channel built into the injection mold to the mold, insert and tube end. After cooling of the thermoplastic material, which is injected into a cavity formed by; at least initially still under pressure during cooling, the parts of the injection mold are separated, the pins are removed and the thermoplastic material The invention is solved by a method of the type mentioned at the outset, characterized in that the tube, which is connected to the insert via the tube, is removed from the first part of the injection mold.

The insert generally consists of plastic, but it is sufficient if the insert consists of another material and has a sufficiently thick plastic coating in the areas where the connection between the insert and the thermoplastic material and between the insert and the tube is to be made. be.

The method according to the invention is suitable for the production of tube-based heat and/or mass exchangers, in which a thermoplastic material is generally melted during injection molding and is injection molded under high pressure via an injection channel. It is injected into a cavity formed by a mold. Pressures of up to 80 bar are used during injection molding of thermoplastic materials. Higher pressures occur depending on the composition of the thermoplastic material and the configuration of the injection mold.

Injection molding according to the method of the invention is not limited to purely thermoplastic materials for injection molding materials. The thermoplastic material may also be mixed with suitable fillers, which can be present in the following forms: - globules or bodies with isotropic dimensions, such as hard fats, metals, oxides, graphites, fluxes, etc. - short rods or other objects whose dimensions are significantly larger in one dimension than in the other two dimensions, such as carbon fibres, asbestos fibres, plastic fibres, natural fibres, etc.; Platelets and other objects whose dimensions are significantly larger in two dimensions than in the third dimension, such as micas such as phlogopite or muscovite.

Furthermore, it may be advantageous to post-process the finished process product, for example the tube base, if appropriate after it has been fitted with other parts such as flanges, tubes, etc.
Irradiation, for example with gamma radiation, X-rays, radio frequency radiation or ultraviolet radiation, may be carried out, thereby increasing the softening point of the injection molded thermoplastic material used.

The term tube covers within the scope of the invention all tubular objects, such as tubes, hoses or hollow fibers. The shape of the cross-section of the tube is not limited to a circular cross-section, ie the tube can also have an oval or polygonal cross-section, for example triangular, square, square, pentagonal, etc.
The wall thickness of the tube formed by the external and internal cross-sectional shapes of the tube may be the same or different around the circumference of the tube. For example, the tube may have a rectangular external cross-sectional profile and a circular or elliptical internal cross-sectional profile. Also, the internal cross section of the tube is 1
It may have more than one through gap. The external and/or internal cross-section of the tube may also have knobs or fins, so that when such a tube is used in a heat and/or mass exchanger, turbulence of the fluid medium is reduced. Flow is increased, thereby providing increased efficiency. The tubes in which the method according to the invention can be particularly advantageously applied generally consist of polymers. Suitable polymers are, for example, polyamides, polyesters, polycarbonates, polypropylene, polyethylene, polyisoptylene, PVC,
Injection moldable copolymers containing tetrafluoroethylene monomers, polyvinylidene fluoride (PVDF), aromatic etherimides, polysulfones, polyethersulfones or polyesteretherketones (PEEK).

The tube is inserted into each hole of the insert such that the tube ends protrude inwardly from the base of the insert. To ensure safe positioning of the tube in the insert during the injection molding process, the tube can be fixed against longitudinal movement.

In the method according to the invention, it is advantageous to temperature-regulate the injection mold for cooling the thermoplastic material. Temperature regulation of the injection mold takes place in the simplest case by holes extending into the upper and/or lower mold and through which a temperature regulating medium, for example water, oil or gas, is conducted. I can do it.

In order to prevent adhesion between the injection molding material and tube and the injection mold and pin, the inner surface of the injection mold and the outer surface of the pin should have smooth surfaces or be polished or the adhesion between the tube and the pin should be avoided. Advantageously, it is coated with a material that prevents this.

Sticking between the pin and the tube can also be effectively avoided by cooling the pin during and/or after injection molding. For this purpose, the pin preferably has a through gap through which a coolant is passed for cooling the pin. Virtually all known liquid or gaseous refrigerants can be used for this purpose. However, it has proven advantageous to use a gas, preferably air or helium, as the refrigerant. Refrigerant may be supplied to the pin via the injection mold and exited through the tube or room air may be drawn in through the pin.

The method according to the invention is particularly advantageous in that several tubes are first joined to form a tube group, which tube group is inserted into a corresponding through hole in the insert base. The hollow fibers may, for example, be embedded as weft threads in the fabric, but also the flexible tubes may be joined to form a tube group if they are bent together. The method according to the invention is facilitated by the tubes being joined axis-parallel or nearly axis-parallel to form a tube group. Such a connection can, for example, advantageously take place in that the cross section of the tube group perpendicular to the tube axis has the form of a plate, for example a flat, contoured or spiral plate.

The joining of the tubes may also take place already during tube manufacture. For this purpose, the tubes may be assembled and glued together while still adhesive during casting.

Tubes with different cross-sections can also be combined to form tube groups. Within the scope of the invention, a plate-like shaped body having several through-gaps and thus having the shape of a tube base, for example, can be referred to as a tube or a group of tubes. This plate-like profile with several through-gaps may have the form of a flat plate, but it may also take the form of a contoured or spiral plate. The shapes of the irregular and spiral plates are shown and described in the drawings.

20-2000 pieces, 20-1000 pieces respectively, preferably
It is advantageous for between 20 and 100 tubes to be assembled to form a tube bank, so that plates with e.g. It has proven advantageous to use it as a starting material.

The method according to the invention preferably uses tubes made of non-porous material or of porous material with a pore volume of up to 90% and having a hydraulic diameter d _h of from 0.5 to 25 mm, preferably from 0.5 to 1.5 mm. can be applied in some cases. Another advantageous range is 0.8-10mm.

The hydraulic diameter d _h is well-known defined as the quotient of 4 x internal cross-sectional area divided by the internal circumference to be wetted (Dubbel, Taschenbuch fujür den Maschinenbau). den Maschinenbau), 13th edition (1970), p. 314]: d _h = 4・Internal cross-sectional area/wet internal circumference Since the hydraulic diameter d _h relates to the internal cross-section,
The condition applies that the hydraulic diameter is 0.5 to 25 mm for each individual through-hole in the case of tube banks or tube sheets.

The method according to the invention comprises a hydraulic diameter of 0.5 to 25 mm or
For tubes of 0.5 to 15 mm, it is advantageous if the wall thickness of the tube has a value of about 5 to 25% of the hydraulic diameter d _h at its thinnest point. Non-porous material or 50%
When using a tube made of porous material with a _pore volume of less than
It is 0.5-5 mm, preferably 0.8-3 mm. In this case, approximately 7.5 to 17.5 of the hydraulic diameter d _h at the thinnest point
Tube wall thicknesses having a value of % are preferred.

The thermoplastic materials used for the tubes, inserts and injection molding preferably consist of thermoplastic polymers. Advantageously, the respective thermoplastic polymers of which the tube, the insert and the thermoplastic material are constructed, at least in the region where the mutual connection takes place, belong to the same type of polymer with respect to their basic structure. It is likewise highly advantageous if the tube, the insert and the thermoplastic material, at least in the area where the mutual bonding takes place, are composed of thermoplastic polymers having the same or approximately the same melting point or melting point range.

With the method according to the invention, no difficulties arise with regard to the sealing quality and strength of the connection between tube and tube base. In particular, the sealing properties and strength of the joint between the tube and the tube base are determined by the fact that at least the tube is heated before injection of the thermoplastic material to a temperature Tc below the melting point temperature of the tube material or the average temperature of the melting range Tm. , the thermoplastic material to be further heated to a melt is heated to a temperature Ti higher than Tm, and the temperature difference Ti−Tm and
Tm-Tc is such that during injection of the melt, the tube is heated to a very high temperature in a short time and is firmly fused to the insert in the region of the hole in the insert, at least over a length corresponding to the wall thickness of the tube. If selected, it will have a favorable effect. Tm corresponds to the melting point temperature in the case of polymers with pronounced melting points.

The exceptional strength of the joint between the tube and the tube base is due to the temperature differences Ti-Tm and Tm-Tc, which cause the tube to be heated to very high temperatures in a short time during injection of the melt, causing the insert to This is achieved by selecting the hole to be rigidly fused with the insert over substantially the entire length of the hole.

The temperature difference Ti−Tm is advantageously between 20 and 90℃, preferably
Selected at 30-70℃. It has been found that with the invention a very strong and durable bond between the tube and the tube base is achieved in the temperature difference range mentioned above. This is particularly the case if the temperature difference Tm - Tc is selected to be at least equal to Ti - Tm and at most equal to Tm - 40°C. The initiation of the melt injection process and the progress of injection must begin with cooling of the tube.

The selected tube temperature to which the tube is heated or cooled is advantageously regulated via the gas conducted by the pin gap before, during and after the injection of the melt.

PVDF, polypropylene, polyethylene or polycarbonate have proven particularly advantageous as thermoplastic materials for tubes, inserts and injection molding materials.

In the device for carrying out the method according to the invention, an insert for positioning the pin in the first part of the injection mold is arranged at least partially in a mating manner; the first part of the mold has one common hole for all the tubes and the insert has one through hole for each tube with an inner dimension equal to the outer dimension of the tube; The second part of the injection mold is provided with a device for accommodating a number of pins having external dimensions equal to the internal dimensions of each tube and a number equal to the tubes of the heat and/or mass exchanger to be produced. Contains: An injection channel is built into the injection mold.

In this case the pins may be used singly or collectively (in
In this case, the pin may be inserted into a tube (Absatz) that can be inserted up to that point.
the second part of the injection mold has a first part such that the pin is oriented in an opening or hole provided for the pin in the second part of the injection mold. mounted on the part. If the number of tubes is very large, the pins may also be collectively interconnected in the localization range of the pins. However, the pin can also be mounted in the second part of the injection mold. In such embodiments, the pin is inserted into the bore of the tube during mounting of the second part onto the first part of the injection mold.

Advantageously, the first and/or second part of the injection mold includes a cooling device. In the simplest case, this device may be a hole extending into the first part or into the second part, through which a coolant, for example cooling water, cooling gas or cooling air, is conducted. The first and/or second part of the injection mold may also include a heating device. The heating device and the cooling device may also be formed from the same device.

Heating and cooling of the pins is advantageously achieved in that the pins each have a through-hole, with all the holes of the pins being connected to the medium distribution device in the second part of the injection mold. It can be done with This medium distribution device may at the same time be a heating and cooling device for the second part of the injection mold.

After the end of the method according to the invention, the insert of the first part of the injection mold, which is part of the tube base of the heat and/or mass exchanger to be produced, preferably consists of a thermoplastic polymer, while the injection mold All other parts of the mold (first part, second part,
(pins, etc.) are made of metal. This ensures good heat supply and heat release in all parts of the injection mold. Suitable metals are, for example, stainless steel, case hardened steel or copper.

The through hole of the insert advantageously has a play with respect to the outer dimensions of the tube. The concept of play (Spielpassung) is defined in DIN 7812, page 2. It is likewise advantageous for the external dimensions of the pin to have some play with respect to the internal dimensions of the tube.

To ensure that the pin can be easily inserted into the tube, the pin is tapered at its free end. The free end of the pin is the end of the pin that is not oriented or fixed in the second part of the injection mold and is provided for insertion into the tube. Furthermore, the pin end has a pointed point, a frustoconically shaped or otherwise shaped taper. The length of the pin is advantageously selected such that the pin protrudes from the hole in the insert during assembly of the injection mold. The length of the pin must therefore be greater than the thickness of the tube base to be manufactured, so that the support of the tube is ensured by the entire length of its embedment in the tube base.

Furthermore, the pin, except for the part where it is incorporated into the second part of the injection mold, advantageously has a slight taper towards its free end, so that it can be used after the end of the injection molding process. It becomes easier to remove the pin from the tube.

However, it is also advantageous to form the pin in such a way that it has a diameter that decreases towards its free end, except where it is taken into the second part of the injection mold. At sufficiently high pressures and sufficiently high temperatures of the molten material in the cavity formed by the parts and inserts of the injection mold, the tube is plastically deformed and fused in the area of the tube base, and this In this way, it can take the shape of a pin. As a result, the tube end is formed into a funnel-shaped tube, and the finished heat-
And/or in the mass exchanger advantageous flow conditions can be set in the region of the tube base.

Another advantage of the device according to the invention is obtained if the insert has at least one circumferential groove on its inner surface. As a result of the flow of molten material into this groove during injection molding, extrusion of thermoplastic material from the insert is also possible in the case of high stresses in the tube base, e.g. due to extreme thermal expansion of the tubes, in the finished heat and/or mass exchanger. be prevented from being

Next, the present invention will be explained in detail with reference to Examples.

Embodiment FIG. 1 is a schematic diagram of the assembled state of a device according to the invention for producing heat and/or mass exchangers containing tubes, in which case the tubes have already been inserted. ing. In the figure, 1 represents the upper mold, and 2 represents the lower mold. A cylindrical insert 3 with a base is inserted into the lower mold 2 and has one through hole 10 for each tube (only one through hole is shown in the diagram). The tube 8 is shown in cross section at the cylindrical insert portion, but the lower die 2
The lower range of is shown as a solid line. The other tube 8 is
For example, as shown in FIG.
It is inserted along. The upper mold 1 consists of a holder 4 into which a refrigerant distribution device 5 and a pin holder 6 are inserted. The holder 4, the refrigerant distribution device 5 and the pin holder 6 may be connected, for example, by a screw located at the location indicated by the dot-dashed line 130. In the pin holder 6,
A pin 7 with a through gap is inserted. Although only one pin 7 is shown for the sake of overview,
For example, other pins 7 may also be arranged along the dashed line 11. The free end of the pin 7 is shaped like a truncated pyramid. The length of the pin is selected such that the free end of the pin projects into the hole of the insert 3 and the length of the pin that projects from the upper mold is greater than the thickness of the tube base to be manufactured. The refrigerant is supplied to the through-hole of the pin 7 via the refrigerant supply port (indicated by arrow B) and the refrigerant distribution device 5, and after leaving the pin, it flows into the tube 8 and can exit from the rear end of the tube. can. The flow direction of the refrigerant is also determined by the refrigerant distribution device 5.
If a suction device is connected to , the direction opposite to arrow B may be selected. During this suction, the air surrounding the injection mold is used as a coolant. The insert 3 has on its outer surface a groove 9 into which the lower mold 2 fits in order to achieve axial fixation of the insert 3. In order to insert the insert 3 into the lower mold, the lower mold is formed in two parts (not shown in the drawing).

An injection channel 12 is built into the upper mold, and this channel allows the molten material for manufacturing the tube base to be introduced into the insert 3, the pin holder 6 (upper mold), and the tube 8 from the direction of arrow A. It is press-fitted under high pressure into the internal cavity 15 formed by. The holder 4 of the upper mold 1 has a hole 13, and the lower mold 2 has a hole 14.
are provided, and a refrigerant can be conducted through these holes.

The arrangement of the tubes in the tube base of a heat and/or mass exchanger that can be produced using the apparatus schematically illustrated in FIG. 1 is illustrated, for example, in FIGS. It is illustrated in . The cross-sectional outline of the tube sheets according to FIGS. 2 to 7 is circular in each case. In these figures, the tube base is 16
, and the tube is designated at 17. In each case, a tube with several through tubes 17 is present. The through tube 17 may be arranged in various ways on the tube base 16. In the case of FIG. 2, the through tube 17 of the tube base 16 is arranged within a hexagonal contour. In FIG. 3, the through pipe 17 of the pipe base 16 is shown.
is placed inside the outline of a rectangle. In the case of FIG. 4, the through tube 17 of the tube base 16 lies within a circular contour (only a portion of the through tube 17 is shown in the drawing). FIG. 5 is a linear layout diagram of the through tube 17, FIG. 6 is a wavy linear layout diagram, and FIG. 7 is a spiral layout diagram.

28 to 30 illustrate different cross-sectional shapes of tubes with only one through-hole. The tube 53 with the through gap 54 according to FIG. 28 has a circular outer cross-section and a circular inner cross-section. In this case, the outer and inner cross-sections can be arranged symmetrically or asymmetrically, as shown in FIG. 28. In the case of an asymmetrical arrangement of the outer and inner cross-sections, the tubes 53 have different wall thicknesses on the periphery.

The tube 55 according to FIG. 29 has a square outer cross-section, but the corners are rounded. The through-hole 56 of this tube 55 likewise has a square cross-sectional shape with rounded corners. In the case of the tube 55 of FIG. 29, instead of a square internal cross-section, a circular internal cross-section may also be present. Similarly, the inner cross-section may be square and the outer cross-section may be circular. Similarly, the external and/or circular cross-section is shown in FIG.
It may also have an oval shape, as shown as tube 57 having a .

When tubes are grouped in parallel to the axis to form a group of tubes, formations such as those illustrated in FIGS. 9-27 and 39 can occur, for example. FIG. 9 shows two plate-like tube groups 18 representing irregularly shaped plates. This irregular shape can be said to be step-like. Through the through-holes 19 it can be seen that both plates 18 each consist of several tubes. Although FIGS. 10-15 illustrate several different shapes of the tubesheet, these figures are shown merely as lines. The respective variants can be described as follows: variant 18 according to FIG. 10: stepped (as detailed in FIG. 9), variant 20 according to FIG. 4: plate with bent edges, FIG. Variant 21 according to:
Roof-shaped bent plate, variant 22 according to FIG. 13: Inclined plate with bent edges, variant 23, 24 according to FIG. 14: Cross-shaped plate, variant 2 according to FIG. 15
5: V-shaped plate. Various profiles of the tubesheet are suitable for presetting specific flow conditions of the medium flowing around the tubesheet.

Several such profiled plates are arranged in parallel to obtain a large exchange surface. This is illustrated in FIG. 8, where a profile plate according to FIGS. 9 and 10 is used, with several plates 18 arranged in parallel. In the case of No. 18, the outline of the irregularly shaped plate is also illustrated, but the illustration of the through gap is omitted, and in the case of No. 18', the irregular shape is simply drawn with lines.

FIG. 16 shows, by way of example, a spiral arrangement of two tube groups, one tube group consisting of tubes 26, the two end tubes marked 26' and 26''. 26 and 2 on the end tubes of the other tube group.
6'''' is attached. Both tube groups are also joined together via a plate tube group to give two spiral plate-tube groups. If the two spiral plate-tube banks are configured as illustrated in FIG.
and/or for a medium to flow around a tube in a mass exchanger, the same medium enters from the outer periphery, for example in the direction of the arrow C, is guided to the center and then directed outwards in the direction of the arrow. A flow path is formed that flows out again in the peripheral direction of D. In this case, the medium changes direction once, which increases the efficiency of such a heat exchanger.

17 to 27 illustrate an example of the internal structure of a tubesheet in partial and schematic cross-sectional views. FIG. 17 shows a through cavity 28 with a circular cross section.
This is a plate 27 having a. The projections 29 on the plate 27 represent turbulence promoters, which are used to create turbulence in the medium flowing around the plate. FIG. 18 shows a bridge plate 30 having a through-hole with a square cross-section and a turbulence generator 32. In FIG. Since the wall thickness of the tube plate according to FIG. 18 is relatively thin, the turbulence starting section 32
can also act as reinforcing ribs for the plate 30. Similarly, in FIG. 19, the air gap 34 penetrates,
A bridge plate 33 with reinforcing walls is shown.
In this case, a turbulence starting section 32 is shown.

FIG. 20 shows a portion of a tube group made up of two different types of tubes. The two types of tubes are primarily distinguished by their different diameters. In the embodiment shown in FIG. 20, the large diameter tubes 35 and the small diameter tubes 36 are alternated. The outer edge of this configuration is provided with a projection 37 of solid material, which serves as a protection against corrosion and damage. The protrusion 37 can be produced, for example, by welding a solid wire to the last tube 35. In the case of Fig. 21, several pipes 3 of the same diameter
8 are joined together.

In FIG. 22, a plate is indicated at 41, which includes a through cavity 40 having an elliptical cross-section. The plate 41 is reinforced at its outer edge as a protection against corrosion and damage. According to FIG. 23, the plate 42 has several circular through-holes 43. The plate 42 is provided with a protrusion 44 (protective protrusion). In the case of FIG. 24, the plate 45 also has a circular through-hole 46.

FIG. 25 shows a bridge plate 4 having a protective protrusion 48.
7 is shown. Similarly, FIG. 26 shows a hollow protective protrusion 5.
A bridge plate with 0 is shown. In the case of the bridge plate 51 shown in FIG. 27, the last bridge on the outer edge of the plate is cut open, into which a solid wire 52 is inserted as a protective projection.

FIG. 31 shows three tubes 59 that are twisted together and also form a group of tubes. A similar arrangement can also be obtained by weaving the tube as a "weft tube."

The cross section illustrated in these figures of a tube or group of tubes is
It is preferably universally suitable for carrying out the process according to the invention for producing heat and/or mass exchangers.

Figures 32 and 33 schematically illustrate the manner in which the tubesheet may be placed within the insert. In FIG. 32, the insert is designated 60, into which tube sheets 61 are inserted in parallel. 62 indicates the thermoplastic material injected by the method of the present invention to join the tube to the insert.

In the insert 63 according to FIG. 33, plates 64 are arranged one after the other and are connected to the insert 63 via a thermoplastic material 65.

Figures 34 and 35 show two embodiments of inserts 66 and 68, in which through holes 67 and 69 are arranged for the installation of tube sheets.

FIG. 36 shows a device according to the invention for producing a plate heat and/or mass exchanger. Insert 70 serving at the same time as a localizing element of the tubesheet
is inserted into the upper mold 71 which is positioned above the lower mold 72. The lower mold 72 has a through gap 73 provided for conducting a refrigerant or a heat medium. An injection flow path 74 is also incorporated in the lower mold 72 in the same manner. A T-shaped gap 75 is cut into the lower die 72. The same gap is the mount of the injection molding equipment and the lower mold 7
Used to hold 2. A pin 79 is inserted into the lower mold 72 in a frictional and engagement manner. Tubesheet 77 is positioned with insert 70 , with all through-gaps 78 of tubesheet 77 containing pins 79 . In the schematic diagram of FIG. 36, the through-holes 78 and pins 79 in the tubesheet 77 are only shown in the left half of the drawing. 76 in Figure 36
represents the gap formed by the lower mold 72, the tube plate 77, the insert 70 and optionally the pin 79, which is to be filled by injection molding with thermoplastic material.

To carry out the method according to the invention, the following procedure is carried out: the lower mold 7 is fixed to the injection molding device.
An insert 70 and an upper mold 71 are mounted on the top of the mold 2.
A tube sheet 77 is then inserted into each through hole of the insert 70 so that the pin 79 is oriented in the through gap 78 of the tube sheet 77. After all the tube sheets 77 are oriented, these tube sheets are fixed by known means so that they will not move in the axial direction. The lower die 72 and the pin 7
After 9 has also been heated to temperature T _c , the thermoplastic polymer is injected under pressure via injection channel 74 . Toward the end of this injection process, the lower mold 72 and eventually the pin 79
cooling is performed. After solidification of the thermoplastic polymer, the upper mold 71, which is formed in two parts for this purpose, can be removed and the insert 70 together with the tube sheet 77 connected thereto can be removed. Next, a new insert 70 and upper mold 71 are positioned on the lower mold 72. The free ends of the tube sheet 77 can now be inserted together into the holes of the second insert 70.

FIG. 37 shows a further device according to the invention for producing a plate heat and/or mass exchanger. In the case of the device, 80 is an insert;
81 indicates an upper mold, and 82 indicates a lower mold. For installation in an injection molding device, pins 89 are inserted in a friction-locking manner into the lower mold 82, which is provided with a T-shaped gap 85, each pin 89 having a through-gauge 90. have All through holes 90 of the pins 89 communicate with a distribution device 91 with which a refrigerant or heat medium can be supplied or drawn through the through holes of the pins 89. The lower mold 82 itself likewise has a heating and cooling device 83 . A plate 87 having a through gap 90 is an insert 8
It is localized at 0. Furthermore, the through gap 8 of the plate 87
8 and pin 89 are shown only in the left half of the drawing.

FIG. 38 illustrates a tube sheet heat exchanger manufactured by the method of the present invention. The tube bank plate 94 is connected at both ends to a welded insert 92 of a half-tube 95 in each case via injection molding material 93 . The tube plate 94' at the forefront is
In the schematic perspective view according to FIG. 39, the tubesheet 94 has been cut open to make it clear that it has more through-gaps than would be seen at the broken edge of the tubesheet 94'. The detailed view X shown in FIG. 39 further clarifies the structure of tube sheet 94'.
The cut-out portion of the tubesheet is designated here by 94'' and the through gap is designated by 96.

A tubesheet heat exchanger manufactured by the method of the invention, illustrated in perspective in FIG.
For example, it is suitable for heating and cooling air. half tube 9
5. Through the upper tube formed by the insert 92 and the thermoplastic polymer 93, a cooling or heating medium can be conducted in the direction of the arrow E, which medium then enters the through gap 96 of the tube bank plate 94. It thus enters the lower tube and flows out from the lower tube in the direction of the arrow F. The air flow blown between the tube sheets from the direction of the arrow G can be heated or cooled. Similarly, a medium entering in the direction of the arrow E and exiting in the direction of the arrow F can be cooled or heated by the same air flow (in the direction of the arrow G).

FIG. 40 schematically shows the structure of an insert 97 having a circumferential groove 98 on its inner surface and a circumferential groove 99 on its outer surface. Such an insert 97 can be installed, for example, in an injection mold according to FIG. The insert 97 is shown in cross section in the right half of the figure and in plan view in the left half. The through gap 100 is shown in cross section. In the plan view, the positions of other through gaps are indicated by dashed lines 101. The circumferential groove 98 on the inner surface of the insert 97 ensures safe prevention of axial movement of the thermoplastic material after injection and curing. The external circumferential groove 99 serves, on the one hand, to secure the insert 97 in the injection mold against axial movement, and on the other hand, the same groove serves, for example, to secure the insert 97 in the injection mold when the insert connected to the tube is inserted into the casing. It can be used for sealing purposes if it is pressed in.

FIG. 41 shows a pin 102 with a free end that is conically shaped. The tip of the free end is truncated and is illustrated in this case in the form of a hemisphere. The other end 103 of the pin 102 is of cylindrical design and is fitted into the bottom of an injection mold, which is shown only schematically.

FIG. 42 shows a pin 105 whose cross section also decreases towards its free end, the external contour of which can be seen as a parabolic curve. The pin 105 is fitted with its cylindrical end into a bottom portion 107, which is shown cut away. If very favorable flow conditions prevail in the finished heat and/or mass exchanger, the fourth
It is easily recognized that the configuration of the pin 105 as shown in FIG. 2 is always advantageous.

In order to avoid parallel cylindrical holes in the bottom of the injection mold, the pin 109
The rear end 108 has a square cross-section so that several identical pins can be juxtaposed which may be fitted together at the bottom of the injection mold. 43rd
The figure shows such an arrangement with six pins 109. Other cross-sections are also proposed for the rear end of the pin 109, for example hexagonal or rectangular cross-sections. In this way, the inlet channel to the pipe can be designed in a flow-technologically advantageous manner.

EXAMPLE 1 In FIG. 1, an apparatus according to the invention for manufacturing tube bases is shown in assembled condition. In this case, 1 represents the upper mold and 2 represents the lower mold. Lower mold 2
into which a cylindrical insert 3 is inserted, the base of which has one through hole 10 for each tube, although only one through hole is shown in this diagrammatic representation. A porous polypropylene tube with dimensions of 5.5/8.6 mm is inserted into the hole 10 of the cylindrical insert 3 up to the upper edge of the cylindrical insert 3. In this case, it is advantageous if the through hole of the cylindrical insert of the lower mold has a play with respect to the outer diameter of the tube that is inserted into the through hole of the cylindrical insert before injection molding. This concept of play is defined in DIN 7182, page 2. It is likewise advantageous for the outer diameter of the pin to have some play with respect to the inner diameter of the tube. The tube 8 is shown in cross section in the region of the cylindrical insert, but not in the lower part of the lower mold 2. The other tube 8 is inserted, for example, along the dashed line 11 as shown in the figure.

The upper mold 1 consists of a holder 4 (material number 1.2419), in which a refrigerant distribution device 5 (material number 1.2419) is installed.
1.2419) and pin holder 6 (material number 1.2419)
is installed. The holder 4, the refrigerant distribution device 5, and the pin holder 6 are connected, for example, to the dashed line 13.
They are connected to each other by screws located at certain positions, denoted by 0.

A pin 7 (material HWS) having a through hole with a diameter of 2 mm is inserted into the pin holder 6. Although only one pin is shown in the figure to make it easier to see the whole, other pins 7 may also be arranged, for example, along the dashed line 11. The free end of the pin 7 is shaped like a truncated pyramid (15°). The length of the pin is set such that the free end of the pin protrudes 15 mm into the hole of the insert 3, so that the length of the pin protruding from the upper mold is greater than the thickness of the tube base to be manufactured. . The thickness of the polypropylene tube base is 0.2·D in the described example.

Refrigerant supply port (indicated by arrow B) and refrigerant distribution device 5
A refrigerant (air 18 DEG C., permissible pressure 0.8-1.0 bar) is introduced into the through-hole of the pin 7 and, after leaving the pin, is injected into the tube 8 and exits from the rear end of the tube.

The insert 3 has a groove 9 on its outer surface with a width of 44 mm and a depth of 2 mm, into which the lower die 2 fits to achieve axial fixation of the insert 3. Lower mold 2
consists of two parts (not shown) for inserting the insert 3 into the lower mold.

The upper mold 1 incorporates an injection channel 12 through which the molten polypropylene material passes from the direction of arrow A to form the insert 3, the pin holder 6 (upper mold) and the tube 8. Cavity 15
It is pressed into the tank at a pressure of 40 bar and a temperature of 235°C.
A sustained pressure of 15 bar is required until the injected polypropylene material cools below its melting point temperature. The plasticized polypropylene material is filled with 30% glass fiber to reduce shrinkage. The melt index of the polypropylene used was 2g/10min.
(according to MFI230-5), and the crystal melting temperature is
The temperature is 160-166°C, and the melting point is 230-240°C.

A hole 13 is provided in the holder 4 of the upper mold 1, and a hole 14 is provided in the lower mold 2, through which a coolant or a heating medium can be conducted to adjust the temperature of the injection mold. Before the first injection, the mold is brought to a working temperature of 70 DEG C. with a liquid heating medium passing through holes 13 and 14.
This temperature is kept constant during the entire injection molding process.

After injection molding is performed, the injection mold to be divided is separated, and the insert 3 provided with the tube base is separated.
is removed from the mold.

Example 2 (Comparative Example) A chrome steel injection mold consists of an upper mold and a lower mold, and when assembled, both molds form a right-angled hexahedron with a length of 200 mm, a width of 150 mm, and a height of 50 mm. The height of the lower mold is 30 mm, and the height of the upper mold is 20 mm.

The lower mold is likewise provided with approximately rectangular depressions, the depth of which is 5 mm, and the distance from their upper edge to the outer edge of the lower mold is each 50 mm. 100
At the bottom of this recess with a surface area of × 50 mm ² 28
Each row has 20 pins inserted. Each row is parallel to the short side of the recess. The spacing between adjacent columns is 3.4
mm, and the spacing between adjacent pins in one row is 2 mm. The rows and pins within each row are centered with respect to the outer edge of the recess.

Each pin is 30 mm long and has an essentially cylindrical shape with an outer diameter of 1.7 mm. The front and back sides of these pins are
It is planarized to a thickness of 1.2 mm, and the planarized surfaces are arranged parallel to the columns. The top 3mm of the pin furthest from the bottom of the recess is tapered.

The upper mold has 28 slits with a spacing of 3.4 mm. The length of each slit is 95 mm and the width is 1.5 mm. The slits are arranged to pass a distance of 55 mm from one side to the other, so that the upper mold looks like a kind of cam. Similarly, it has a cam shape and has 28 teeth with a mutual spacing of 3.4 mm.
A side block having a cylindrical shape is pushed into the upper mold from the block side and fixed in such a way that the teeth of the block are arranged in the slits of the upper mold. The width of each tooth on the side block is 1.45mm, the length is 55mm, and the height is 20mm.
40 mm long slit-like holes are opened when the side block is connected to the upper mold, and when the upper mold is attached to the lower mold, the tips of the pins are positioned in these holes.

Rectangular cross section with rounded corners (maximum length 1.75mm, maximum width 1.25mm) with external width 39.9mm and external thickness 1.4mm
mm, curvature r = 0.2 mm) through hole (channel) 20
A polyvinylidene fluoride tube sheet with a tube plate disposed therein is inserted into each row of pins so that it abuts the bottom of a recess provided in the lower mold.

Now the injection mold is brought to a temperature of 25°C. Polyvinylidene fluoride (Tm = 176 °C, the PVDF used has a melt index according to ISO standard 1133 in addition to this melting point) by means of an injection channel in the injection mold parallel to the long side of the depression. The melt index takes a value of 5.5 at 235°C and a value of 10.0 at 270°C, the latter temperature being important in Example 7) when injected as a melt. The melt has a temperature of 235° C. upon entering the cavity. Once the injection mold is completely filled with melt, the pressure applied to the melt is kept at 30 bar until the temperature of the injection melt drops to 160 °C.

After complete cooling and solidification of the melt, the tube base formed, together with the connected tube, is removed from the injection mold.

The tube base molded from the melt is approximately 4% smaller in volume than the volume of the lower mold cavity.
Due to volume contraction during solidification of the melt, the tube sheet is fixed at the tube base in such a way that its surface has a corrugated or wrinkled surface at the location of the tube sheet's protrusion from the tube base. Normally, the internal pressure at which the intermediate wall of an uncast tubesheet ruptures within 60 seconds is approximately
28 bar. However, if the tubesheet is cast as described above, it will burst within 60 seconds at a pressure of 6 bar.

Example 3 (Comparative Example) Proceed as in Example 2. Before the PFDF (polyvinylidene fluoride) melt is injected into the cavity, the temperature of the injection mold and therefore also the tube sheet is controlled by a heating medium (oil).
It is then heated to 65°C. The heating medium is sucked in for this purpose by channels provided in the injection mold.

The bonded tube base of the tube sheet now formed from this has a volume shrinkage of 4.6%. The tube sheet is
It also has corrugations or wrinkles at the point where it protrudes from the tube base. The pressure at which the tubesheet ruptures within 60 seconds is again approximately 6 bar.

Example 4 The upper mold according to example 2, in which the side blocks have already been pushed in and fixed, is provided with a recess having a depth of 3 mm, a length of 102 mm and a width of 52 mm. In this hollow
An insert made of PVDF is inserted. The insert is 3 mm thick, 101 mm long and 51 mm wide.
Depending on the arrangement of the pins, the insert has slits that match the slits formed by the upper mold and the side blocks and are arranged in a row after insertion.
It has 28 pieces.

After the injection mold has been assembled with the insert and the tubesheet has been inserted as described in Example 1, the injection mold is heated to 25 °C and then the melt with a temperature of 235 °C consisting of PVDF is is injected into the cavity of the lower mold until a pressure of 30 bar is obtained.
Now, the injection mold is cooled to 160°C under this pressure. After complete cooling, the insert, which is now connected to the tube sheet via the injection molding material, is removed from the injection mold.

The volumetric shrinkage of the tube base is now only 2.3% relative to the volume of the lower mold cavity. The tubesheet does not form corrugations or wrinkles in any location and the pressure at which the tubesheet bursts within 60 seconds is approximately 28 bar.

If a tube sheet is to be removed from the tube base formed from the insert and the injection molded material, a tensile load of approximately 250 N per tube sheet must be applied for this purpose.

Example 5 Example 4 is repeated, but before the injection molding material is injected, the temperature of the injection mold and thus of the tubesheet insert is adjusted to 65°C.

After removing the part formed from the tubesheet, insert and injection molding material from the injection mold, the volumetric shrinkage is 2.2% and the bursting pressure is also 28 bar, while the tubesheet can withstand even a tensile load of 1350N. It is confirmed that it cannot be removed from the tube base.

Example 6 Repeat Example 4, but when injecting the injection molding material, the temperature of the injection mold is adjusted to 110°C, while the temperature of the insert and tubesheet are adjusted to 110°C after they are installed in the injection mold. It was raised in a separate furnace to a temperature of 145°C.

Once the injection mold has cooled down, the pressure with which the material is injected is reduced from 30 bar to 15 bar, but after 15 seconds it is increased to 40 bar, left at this pressure for 15 seconds, and then The pressure is reduced to 0 bar.

This method allows the injection mold to be additionally filled with injection molding material after cooling, thereby compensating for the shrinkage of the initially introduced material.

After removing the tubesheet, insert and the part formed from the injection molding material from the injection mold, ensure that the volumetric shrinkage of the injection molding material is only 2% and the bursting pressure is still 28 bar. I can do it. The tubesheet cannot be extracted from the tube base even under a tensile load of 1350N.

Example 7 The conditions of Example 5 are maintained, but the injection temperature of the PVDF melt is increased to 270°C. During injection of the melt, the melt flows out of the slit in the upper mold (between the slit wall and the outer wall of the tube sheet) at a pressure that should reach 30 bar.

Nevertheless, the product produced by this method still has a burst pressure of 28 bar. The tube sheet is approx.
It cannot be removed from the pipe base under a tensile load of 1000N. When applying a tensile load of 1000 N, stretching can be observed in some tube sheets in the area of the melt outflow location. In the case of these tubesheets, such amount of polymer has been drained that the polymer contacts the tubesheet in areas where it is no longer supported by the pins, so that the tubesheet is significantly deformed and partially deformed. has air bubbles on the wall.

This example shows that an excessively high selected temperature of the melt makes the success of the method according to the invention uncertain. However, the outflow of the melt through the slit will reduce the dimensions of the slit in the tubesheet and insert at the above temperatures, such that the gap between the tubesheet and the slit wall is reduced (e.g. tubesheet thickness 1.45 mm, slit width
1.5mm).

Example 8 Repeat Example 4, but before injecting the injection molding material to which 20% phlogopite (Mica) has been added evenly distributed, the temperature of the injection mold and tubesheet insert is increased to 80°C. Adjust to ℃. The maximum size of the micro mica plate was 300·10 ^-6 m.

After removing the tubesheet, the insert and the part formed from the injection molding material from the injection mold, it can be seen that the volumetric shrinkage of the injection molding material is likewise 2%, while the bursting pressure is 28 bar. The tube plate is
Even with a tensile load of 1350N, it could not be extracted from the tube base.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a device according to the invention for producing a heat and/or mass exchanger provided with tubes; FIGS. 2 to 7 are schematic illustrations of tubes with multiple through-holes; 8 is a schematic cross-sectional view of the irregularly shaped tube sheet, FIG. 9 is a perspective view of the irregularly shaped tube sheet, and FIG.
15 to 15 are schematic cross-sectional views showing various variants of tube sheets, FIG. 16 is a schematic cross-sectional view of a group of tubes in a spiral arrangement, and FIGS. 17 to 27 are schematic cross-sectional views showing various types of tube sheets. Schematic cross-sectional views of a tube sheet; FIGS. 28-30 are possible cross-sectional views of a single tube; FIG. 31 is a perspective view of a group of twisted tubes; FIGS. 32 and 33; is a schematic cross-sectional view of the tubesheet arranged in the insert,
34 and 35 are perspective views showing two embodiments of the insert, FIGS. 36 and 37 are schematic cross-sectional views of an apparatus for producing plate heat and/or mass exchangers according to the invention, and FIG. 38 39 is a perspective view of the X portion of FIG. 38; FIG. 40 is a schematic vertical sectional view of an insert having circumferential grooves; FIG. Figure and No. 42
The figure is a longitudinal sectional view showing an embodiment of the pin, and FIG. 43 is a perspective view showing the arrangement of several pins shown in FIG. 42. In the figure: 1, 72, 82...the second part of the injection mold,
2, 71, 81...first part of injection mold,
3, 70, 80, 97... insert, 7, 7
9,89...pin, 8...tube, 12,74,87
...Injection flow path, 13; 14, 73, 77, 87...
...Tube group, 83...Temperature control device, 98...Circumferential groove.

Claims (1)

Claims: 1. A heat and/or mass exchanger comprising a tube made of plastic, an injection mold consisting of at least two parts, for example an upper mold and a lower mold, and a pin insertable into said tube. In the method of manufacturing a thermoplastic material by injection molding, the first part of the injection mold (upper mold or lower mold) is made of plastic and is connectable to the tube by fusion. an insert having a base having one through hole for each tube as a positioning element for the tube, the insert being arranged in an at least partially mating manner in the first part of the injection mold; the tubes are inserted into each hole of the insert; a pin is inserted into each tube, and then the injection mold is inserted so that the pin is in the second part (lower mold or upper mold) of the injection mold. The molten thermoplastic material is inserted into the injection mold, the insert and the tube end via an injection channel built into the injection mold. After cooling of the thermoplastic material, which is injected into the cavity thus formed; at least initially still kept under pressure during cooling, the parts of the injection mold are separated, the pins are removed and the thermoplastic material is A method as described above, characterized in that the tube, which is connected to the insert via the tube, is removed from the first part of the injection mold. 2. The method of claim 1, wherein the molten material is injected under high pressure into the cavity formed by the injection mold, the insert and the tube end. 3. A method according to claim 1 or 2, wherein the tube is inserted into each hole of the insert such that the tube end projects inwardly from the base of the insert. 4. A method according to any one of claims 1 to 3, wherein the temperature of the injection mold is adjusted for cooling the thermoplastic material. 5. A method according to any one of claims 1 to 4, wherein the pin is cooled during and/or after injection molding. 6. The method of claim 5, wherein the pin has a through hole through which a coolant is passed for cooling the pin. 7. A method according to claim 6, wherein a gas, preferably air, is used as refrigerant. 8 First, several tubes are combined to form a tube group,
8. The method as claimed in claim 1, wherein the tube group is inserted into a corresponding through hole in the insert base. 9 Tubes are grouped axially parallel or approximately axially parallel so that the tube group cross-section perpendicular to the tube axis has the shape of a plate, e.g. a flat, irregular or spiral plate. 9. A method according to claim 8, formed in the form of: 10 20-2000 pieces each, preferably 20-100 pieces
10. The method according to claim 8, wherein individual tubes are grouped together to form a group of tubes. 11 Made of non-porous material or porous material with a pore volume of up to 90%, hydraulic diameter d _h 0.5 ~
11. The method according to claim 1, wherein a tube having a diameter of 25 mm is used, preferably between 0.8 and 15 mm. 12 Claim 1, wherein the wall thickness of the pipe at its thinnest point is about 5 to 25% of the hydraulic diameter.
The method described in Section 1. 13. A tube made of a non-porous material or of a porous material with a pore volume of less than 50% and having a hydraulic diameter d _h of 0.5 mm, preferably from 0.8 to 3 mm is inserted. Method described. 14 The wall thickness of the pipe at its thinnest point is the hydraulic diameter.
14. The method of claim 13, having a value of d _h of about 7.5 to 17.5%. 15. Any of claims 1 to 14, in which the tube, the insert and the thermoplastic material, at least in the area where the mutual bonding takes place, consist of thermoplastic polymers belonging to the same class of polymers with respect to their basic structure. or the method described in item 1. 16. Claims 1 to 15, wherein the tube, the insert and the thermoplastic material, at least in the area where the mutual bonding takes place, consist of thermoplastic polymers having the same or nearly the same melting point or melting point range. The method according to any one of the above. 17. Before injection of the thermoplastic material, at least the tube is heated to the melting point temperature or the average temperature of the melting point range of the tube material.
The thermoplastic material to be further heated is heated to a temperature Ti higher than _Tm ; and the temperature differences Ti - Tm and Tm - Tc cause the tube to be shortened during injection of the melt. Claim 15 or Claim 16, wherein the tube is heated to a very high temperature for a period of time and is selected so as to firmly integrate with the insert in the region of the hole of the insert over a length at least corresponding to the wall thickness of the tube. Method described. 18 The temperature differences Ti - Tm and Tm - Tc are selected such that during injection of the melt the tube is heated to a very high temperature in a short time and merges with the insert over almost the entire length of the hole in the insert. 18. The method according to claim 17. 19 Temperature difference Ti-Tm is 20 to 90℃, preferably 30
19. A method according to claim 17 or 18, wherein the temperature is selected at -70<0>C. 20. The method according to any one of claims 17 to 19, wherein the temperature difference Tm - Tc is selected to be at least equal to Ti - Tm and at most equal to Tm - 40°C. 21. The method according to any one of claims 6 to 20, wherein the selected tube temperature is regulated by a gas passed through the cavity of the pin during and after the injection of the melt. . 22. The thermoplastic material of the tube, insert and injection molding material comprises an injection moldable copolymer based on a fluorinated carbon compound, for example PVDF. the method of. 23. A method according to any one of claims 1 to 21, wherein the thermoplastic material of the tube, insert and injection molding material consists of polypropylene. 24. A method according to any one of claims 1 to 21, wherein the thermoplastic material of the tube, insert and injection molding material consists of polyethylene. 25. The method of any one of claims 1 to 21, wherein the thermoplastic material of the tube, insert and injection molding material consists of polybisphenol carbonate.