DE102022131063A1 - Heat exchanger - Google Patents

Abstract

Heat exchanger comprising a housing and a heat exchanger tube, wherein the heat exchanger tube is arranged in an interior of the housing, wherein the housing has two cover plates, a hollow cylindrical outer wall with a cylinder axis and at least two screws, wherein the outer wall extends between the cover plates so that the two cover plates extend substantially perpendicular to the cylinder axis, and wherein the two screws clamp the cover plates in the axial direction against the outer wall.

Description

Technical area

The present disclosure relates to a heat exchanger comprising a housing and a heat exchanger tube, wherein the heat exchanger tube is arranged in an interior of the housing.

Technological background

Heat exchangers are used to transfer thermal energy from a material stream flowing in the heat exchanger tube to another material located inside the housing, or vice versa. The process is used in many technical fields, for example in air conditioning technology, cooling technology in industrial production plants or in energy technology for handling liquid gas.

In the chemical and pharmaceutical industries, for example, heat exchangers are used in which liquid nitrogen is passed through the heat exchanger tube, thereby cooling a heat transfer medium inside the heat exchanger housing. The heat transfer medium can then be used, for example, to cool a reactor. This offers the advantage that the liquid nitrogen does not come into direct contact with the materials being produced. In this way, the temperature of the production process can be better controlled, the risk of severe undercooling of the product mixture can be reduced and excessive liquid nitrogen consumption can be prevented.

Heat exchangers are used in various places when handling liquid gas. For example, heat exchangers are used to cool or liquefy a fluid, but are also used for heating or re-evaporation. Fluids include gases and liquids. Helium, hydrogen, argon or nitrogen are particularly used in the heat exchanger tube.

When using a heat exchanger, there is often a high pressure in the heat exchanger tube and in the interior of the heat exchanger housing, which the heat exchanger housing must withstand. For process temperatures in the low temperature range, high-alloy stainless steels are generally used, which are designed as seamlessly as possible as a housing or heat exchanger tube. Individual components of the heat exchanger housing are precisely welded using devices known from the state of the art in order to ensure sufficient pressure stability.

In order to ensure the safety of the heat exchanger in the long term, the housing and the heat exchanger tube must be maintained at regular intervals. For the welded housings mentioned above, this means welding the housing before maintenance and then welding the housing again after maintenance. This leads to a high level of time required for maintenance.

The present disclosure is therefore based on the aspect of providing a heat exchanger which facilitates the maintenance of the interior of the housing, but at the same time offers sufficient pressure stability for various applications.

Summary of Revelation

The aspect underlying the present disclosure is solved by a heat exchanger according to the appended independent claim. For this purpose, the housing of the heat exchanger has the two cover plates mentioned at the beginning, a hollow cylindrical outer wall with a cylinder axis and at least two screws, wherein the outer wall extends between the cover plates so that the two cover plates extend substantially perpendicular to the cylinder axis, and wherein the two screws clamp the cover plates in the axial direction against the outer wall.

In contrast to heat exchangers known from the prior art, the housing of the heat exchanger according to the disclosure has several components that are only clamped together by a screw connection. Welding of the components is not necessary, so maintenance is carried out by separating the components from one another by loosening the screws. This leads to a significant time saving when maintaining the heat exchanger according to the disclosure. At the same time, the two screws that clamp the cover plates against the outer wall in the axial direction ensure that the housing has sufficient pressure stability.

Preferably, the at least two screws for tensioning the cover plates against the outer wall are passed through corresponding openings in a first of the two cover plates and engaged with the second cover plate so that the cover plates are tensioned towards each other.

Alternatively, in a further embodiment, the outer wall has a first collar and a second collar with which the screw ben to tension the cover plates against the outer wall.

Various designs of screws can be used as screw connections to ensure sufficient tension of the cover plates against the outer wall.

In one embodiment, a through-bolt is used for each of the two screws, which is passed through a through hole in the second cover plate and tightened with a nut. It goes without saying that the screw head is larger than the diameter of the opening in the first cover plate, so that tightening is possible.

Alternatively, in one embodiment, the screws are a threaded rod, the ends of which are each tightened against the two cover plates with a nut. In both embodiments, the nut can also be designed as a hydraulic nut.

Alternatively, in one embodiment, a thread is provided in one of the cover plates, with which the screw is engaged.

In a further embodiment, the housing has at least three screws that clamp the cover plates against the outer wall. The more screws that clamp the cover plates, the more evenly the clamping force is transferred to the outer wall of the housing and deformation of the outer wall is prevented.

In a further embodiment, the two screws are expansion screws which are pre-tensioned so that they tension the cover plates towards each other and against the outer wall even when the heat exchanger and thus the material of the screws heats up. An expansion screw is an elastically stretchable screw which is characterized by a shaft which has a thinner diameter than a threaded section of the screw and which works according to the principle of a pre-tensioned tension spring. This offers the advantage that the tensile force exerted by the screw changes only slightly, even through plastic deformation of the screw, e.g. through thermal heating, and the pressure stability of the housing according to the disclosure is thus guaranteed even at different temperature ranges.

In a further embodiment, at least one of the two screws has a defined breaking strength for forming a break protection for the heat exchanger against excess pressure in the housing. If the pressure in the interior of the housing therefore exceeds a certain value, the screws break and the pressure escapes from the interior of the housing. This increases the operational reliability of the heat exchanger according to the disclosure.

In a further embodiment, the two cover plates and the outer wall are at least two, preferably three separate parts that are not connected to one another in a material-locking manner. This simplifies maintenance if not all parts are connected to one another in a material-locking manner. For example, in one embodiment, one of the covers is connected to the outer wall in a material-locking manner, while the second cover is a separate part.

In one embodiment, an annular first groove is formed in a surface of one of the two cover plates, the outer wall extending into the first groove in the axial direction.

In a further embodiment, an annular first groove is formed in a surface of each of the two cover plates, with the outer wall extending into each of the two first grooves in the axial direction. This results in the outer wall being stably clamped between the cover plates.

In a further embodiment, the first groove, but in particular each of the two first grooves, has a substantially U-shaped cross-sectional profile in a radial plane that is spanned by the cylinder axis and a radius perpendicular to the cylinder axis. In one embodiment, the first groove, in particular each of the two first grooves, has two annular side wall surfaces facing each other, wherein a first O-ring seal is arranged in the first groove, in particular in each of the two first grooves, such that the first O-ring seal is in sealing contact with a first of the two side wall surfaces and the outer wall. In particular, in one embodiment, the O-ring seal is embedded in the first of the two side wall surfaces of each of the two first grooves and/or the outer wall is chamfered at its ends. It goes without saying that other cross-sectional profiles, such as a V-shaped cross-sectional profile or an angular cross-sectional profile, are also possible for the design of the first groove or the first grooves.

In a further embodiment, a second O-ring seal is arranged in the first groove, in particular in each of the two first grooves, such that the second O-ring seal is in sealing contact with a second of the two side wall surfaces and the outer wall. In one embodiment, the second O-ring seal is in the second of the two side wall surfaces of the first groove, in particular each of the first two grooves.

The O-ring seals ensure that the medium is held securely in the interior of the housing.

The arrangement of the outer wall in a groove of the cover plates also offers the advantage that a leakage of the heat exchanger housing can be easily detected in the area of the groove if the medium penetrates from the interior of the housing into the space formed by the groove between the first O-ring seal and the second O-ring seal.

In one embodiment, the heat exchanger therefore has a housing leak detector, wherein the housing leak detector is set up and arranged such that it detects a leak in the housing during operation of the heat exchanger, wherein the housing leak detector is in fluid communication with at least one of the two first grooves via a housing leak detector line, wherein the housing leak detector line opens into a region of the respective groove sealed by the two O-ring seals.

In a further embodiment, the housing has a hollow cylindrical inner wall, wherein the outer wall concentrically surrounds the inner wall, so that the interior of the housing is ring-shaped. In a further embodiment, the cover plates are also ring-shaped, so that the heat exchanger has a passage in the middle, which is enclosed by the inner wall and through which, for example, lines or fastening means are passed.

In one embodiment, an annular second groove is formed in the surface of one of the two cover plates, the inner wall extending into the second groove in the axial direction. In one embodiment, an annular second groove is formed in the surface of each of the two cover plates, the inner wall extending into each of the second grooves in the axial direction. It is understood that in one embodiment, the design and sealing of the second grooves is the same as that of the first grooves, as previously described in embodiments thereof. This also applies in particular to the design of the housing leak detector, the housing leak detector line of which in one embodiment is in fluid communication with one of the two second grooves.

In one embodiment, each of the first and second grooves is in fluid communication with a housing leak detector via a housing leak detector line.

In a further embodiment, the heat exchanger has a heat exchanger tube leak detector, wherein the heat exchanger tube leak detector is set up and arranged such that it detects a leak in the heat exchanger tube during operation of the heat exchanger, wherein the heat exchanger tube leak detector is in fluid communication with the interior of the housing via a heat exchanger tube leak detector line and wherein the heat exchanger tube leak detector line opens into the interior.

The heat exchanger tube leak detector is preferably a pressure detector or a gas sensor, for example a helium detector. This makes it possible to reliably determine whether the material flowing through the heat exchanger tube penetrates into the interior of the housing.

In a further embodiment, the heat exchanger tube is guided through one of the two cover plates. In particular, in a further embodiment, the passage is realized using a cutting ring screw connection.

In a further embodiment, the heat exchanger tube is designed in a spiral shape. This leads to an increase in the surface area of the heat exchanger tube, whereby the thermal energy is transferred particularly effectively from the heat exchanger tube to the medium in the interior of the heat exchanger.

Possible materials for the heat exchanger tube, especially if in one embodiment helium flows through the heat exchanger tube, are TP316L, HP120 or Grade X.

Short character description

Further advantages, features and possible applications of the present disclosure will become clear from the following description of two embodiments and the associated figures. Identical components are provided with the same reference numerals.

• 1a zeigt eine schematische Darstellung eines Schnitts parallel zur Zylinderachse durch eine erste Variante eines Wärmetauschers.
• 1b zeigt einen Ausschnitt der unteren linken Ecke der in 1a dargestellten Variante
• 2 zeigt eine schematische Darstellung eines Schnitts parallel zur Zylinderachse durch eine zweite Variante eines Wärmetauschers.
• 3 zeigt eine schematische Darstellung eines Schnitts parallel zur Zylinderachse durch eine dritte Variante eines Wärmetauschers.

The foregoing general description, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the accompanying figures. It is to be understood that the illustrated embodiments are not limited to the precise arrangements shown.

• 1a shows a schematic representation of a section parallel to the cylinder axis through a first variant of a heat exchanger.
• 1b shows a section of the lower left corner of the 1a shown variant
• 2 shows a schematic representation of a section parallel to the cylinder axis through a second variant of a heat exchanger.
• 3 shows a schematic representation of a section parallel to the cylinder axis through a third variant of a heat exchanger.

Detailed description

The one in the 1a and 1b The heat exchanger 1 shown has a housing 2 and a heat exchanger tube 3 arranged in the interior 4 of the housing 2. The heat exchanger tube 3 is spiral-shaped and made of TP316L, HP120 or Grade X.

The housing 2 is formed from two cover plates 2a, 2b and a hollow cylindrical outer wall 2c, which enclose the interior 4. The hollow cylindrical outer wall 2c is arranged cylindrically around a cylinder axis 100, to which the two cover plates 2a, 2b extend essentially perpendicularly. The heat exchanger tube 3 is guided through both of the two cover plates 2a, 2b. The two cover plates 2a, 2b and the outer wall 2c are separate components that are clamped against each other by means of eight screws 5a, 5b (in the sectional view shown, only two screws 5a, 5b are visible).

The screws 5a, 5b are designed in such a way that they are guided through an opening in a first 2a of the two cover plates 2a, 2b, wherein a diameter of the screw head of the screws 5a, 5b is selected such that the screws 5a, 5b cannot be guided completely through the opening of the first cover plate 2a. In the second 2b of the two cover plates 2a, 2b, a further through-opening is provided for the screws 5a, 5b, through which a threaded section of the screws 5a, 5b is guided. At the end of the threaded section, a hydraulic nut is provided, with which the cover plates 2a, 2b are clamped towards each other and against the outer wall 2c. Alternatively, the screws 5a, 5b are a threaded rod, which is clamped at its ends with a nut against the cover plates 2a, 2b and the outer wall 2c.

To accommodate the outer wall 2c, a first groove 21a, 21b is provided in the surface 20a, 20b of the cover plates 2a, 2b, into which the outer wall 2c extends in the axial direction.

By clamping the cover plates 2a, 2b against the outer wall 2c, a pressure-stable housing 2 is achieved, which also meets the requirements of low-temperature applications for heat exchangers 1 and at the same time offers simplified maintenance options.

The screws 5a, 5b are preferably expansion screws which are pre-tensioned so that they tension the cover plates 2a, 2b towards each other and against the outer wall 2c even when the heat exchanger 1 and thus the screws 5a, 5b are heated. The screws 5a, 5b also have a defined breaking strength in order to ensure that the heat exchanger 1 is protected against breaking if the pressure in the interior 4 of the housing 2 exceeds a certain value.

In order to seal the interior 4 of the housing 2, a first O-ring seal 61a, 61b and a second O-ring seal 62a, 62b are arranged in the first grooves 21a, 21b. The first grooves 21a, 21b have a substantially U-shaped cross-sectional profile in a radial plane spanned by the cylinder axis 100 and a radius 101 perpendicular to the cylinder axis 100, so that each of the two first grooves 21a, 21b has two annular side wall surfaces 221a, 221a', 221b, 221b' facing each other. The side wall surfaces 221a, 221a', 221b, 221b' are designed such that the first O-ring seals 61a, 61b are in contact with the first 221a, 221b of the respective two side wall surfaces 221a, 221a', 221b, 221b' and the second O-ring seals 62a, 62b are in contact with the second 221a', 221b' of the respective two side wall surfaces 221a, 221a', 221b, 221b'. As a result, the first and second O-ring seals 61a, 61b, 62a, 62b are each in contact with the outer wall 2c and the respective side wall surfaces 221a, 221a', 221b, 221b' of the first grooves 21a, 21b. Furthermore, in particular 1b It can be seen that the ends of the outer wall 2c are chamfered so that the first and second O-ring seals 61a, 61b, 62a, 62b can fit into the first grooves 21a, 21b.

In order to detect a leak in the housing 2, the heat exchanger 1 also has a housing leak detector 6, which is in fluid communication with at least one of the two first grooves 21a, 21b via a housing leak detector line 7, wherein the housing leak detector 7 opens into an area 8 of the respective groove 21a, 21b that is sealed by the two O-ring seals 61a, 62a or 61b, 62b. Due to this arrangement, the housing leak detector 6 detects, for example, a pressure change in the sealed area 8 when medium from the interior 4 penetrates into the actually sealed area 8.

Furthermore, the heat exchanger 1 in 1 a heat exchanger tube leak detector 9, which is in fluid communication with the interior 4 via a heat exchanger tube leak detector line 10. The heat exchanger tube leak detector 9 is, for example, a gas sensor that detects a specific gas in the interior 4 that flows through the heat exchanger tube 3 and unintentionally escapes from it.

In the 2 The variant of the heat exchanger shown differs from the one in the 1a and 1b shown variant in that the outer wall 2c has a first collar 32a and a second collar 32b which protrudes from the outer wall 2c in the direction of the radius 101, wherein the screws 5a, 5b are brought into engagement with the collars 32a, 32b of the outer wall 2c in order to prestress the cover plates 2a, 2b against the outer wall 2c.

The 3 Heat exchanger 1 shown differs from that shown in the 1a and 1b shown heat exchanger 1 only in that the housing 2 further has a hollow cylindrical inner wall 2d, wherein the outer wall 2c concentrically surrounds the inner wall 2d, so that the interior 4 of the housing 2 is ring-shaped. The heat exchanger tube 3 winds in a spiral shape and the inner wall 2d of the housing 2.

To clamp the inner wall 2d, the surface 20a, 20b of the two cover plates 2a, 2b each has a second groove 22a, 22b into which the inner wall 2d extends in the axial direction. For the sake of simplicity, the seal of the inner wall 2d has not been provided with reference numerals. However, the structure is analogous to the structure described for the outer wall 2c and also has a first and a second O-ring seal which are in contact with the inner wall and the side wall surfaces of the second grooves 22a, 22b.

List of reference symbols

1

Heat exchanger

2

Housing

2a, 2b

Cover plates

2c

Exterior wall

2d

Interior wall

3

Heat exchanger tube

4

inner space

5a, 5b

Screws

6

Housing leak detector

7

Housing leak detector line

8th

sealed area

9

Heat exchanger tube leak detector

10

Heat exchanger tube leak detector line

20a, 20b

Surface of the cover plates

21a, 21b

first grooves

22a, 22b

second grooves

32a, 32b

Collar of the outer wall

61a, 61b

first O-ring seals

62a, 62b

second O-ring seals

100

Cylinder axis

101

radius

221a, 221b, 221a', 221b'

Side wall surfaces of the first grooves

Claims (13)

Heat exchanger (1) having a housing (2) and a heat exchanger tube (3), wherein the heat exchanger tube (3) is arranged in an interior space (4) of the housing (2), characterized in that the housing (2) has two cover plates (2a, 2b), a hollow cylindrical outer wall (2c) with a cylinder axis (100) and at least two screws (5a, 5b), wherein the outer wall (2c) extends between the cover plates (2a, 2b) so that the two cover plates (2a, 2b) extend substantially perpendicular to the cylinder axis (100), and wherein the two screws (5a, 5b) clamp the cover plates (2a, 2b) in the axial direction against the outer wall (2c). Heat exchanger (1) according to one of the preceding claims, wherein the two screws (5a, 5b) are expansion screws which are pre-tensioned so that they tension the cover plates (2a, 2b) towards each other and against the outer wall even when the heat exchanger (1) is heated. Heat exchanger (1) according to one of the preceding claims, wherein at least one of the two screws (5a, 5b) is used to form a Fracture protection of the heat exchanger (1) against excess pressure in the housing (2) has a defined breaking strength. Heat exchanger (1) according to one of the preceding claims, wherein the two cover plates (2a, 2b) and the outer wall (2c) are at least two, preferably three separate parts which are not integrally connected to one another. Heat exchanger (1) according to one of the preceding claims, wherein an annular first groove (21a, 21b) is recessed into a surface (20a, 20b) of each of the two cover plates (2a, 2b), wherein the outer wall (2c) extends into each of the two first grooves (21a, 21b) in the axial direction. Heat exchanger (1) according to the preceding claim, wherein each of the two first grooves (21a, 21b) has a substantially U-shaped cross-sectional profile in a radial plane spanned by the cylinder axis (100) and a radius (101) perpendicular to the cylinder axis (100), so that preferably each of the two first grooves (21a, 21b) has two annular side wall surfaces (221a, 221a', 221b, 221b') facing each other, wherein in each of the two first grooves (21a, 21b) a first O-ring seal (61a, 61b) is arranged such that the first O-ring seal (61a, 61b) is in sealing contact with a first (221a, 221b) of the two side wall surfaces (221 a, 221a', 221b, 221b') and the outer wall (2c) is. Heat exchanger (1) according to the preceding claim, wherein in each of the two first grooves (21a, 21b) a second O-ring seal (62a, 62b) is arranged such that the second O-ring seal (62a, 62b) is in sealing contact with a second (221a', 221b') of the two side wall surfaces (221a, 221', 221b, 221b') and the outer wall (2c). Heat exchanger (1) according to the preceding claim, wherein the heat exchanger (1) has a housing leak detector (6), wherein the housing leak detector (6) is set up and arranged such that it detects a leak in the housing (2) during operation of the heat exchanger (1), wherein the housing leak detector (6) is in fluid communication with at least one of the two first grooves (21a, 21b) via a housing leak detector line (7), wherein the housing leak detector line (7) opens into a region (8) of the respective groove (21a, 21b) sealed by the two O-ring seals (61a, 61b). Heat exchanger (1) according to one of the preceding claims, wherein the housing (2) has a hollow cylindrical inner wall (2d), wherein the outer wall (2c) concentrically surrounds the inner wall (2d) so that the interior space (4) of the housing (2) is annular. Heat exchanger (1) according to the preceding claim, wherein an annular second groove (22a, 22b) is recessed into the surface (20a, 20b) of each of the two cover plates (2a, 2b), wherein the inner wall (2d) extends into each of the second grooves (22a, 22b) in the axial direction. Heat exchanger (1) according to one of the preceding claims, wherein the heat exchanger (1) has a heat exchanger tube leak detector (9), wherein the heat exchanger tube leak detector (9) is set up and arranged such that it detects a leak in the heat exchanger tube (3) during operation of the heat exchanger (1), wherein the heat exchanger tube leak detector (9) is in fluid communication with the interior (4) of the housing (2) via a heat exchanger tube leak detector line (10) and wherein the heat exchanger tube leak detector line (10) opens into the interior (4). Heat exchanger (1) according to one of the preceding claims, wherein the heat exchanger tube (3) is passed through at least one of the two cover plates (2a, 2b). Heat exchanger (1) according to one of the preceding claims, wherein the heat exchanger tube (3) is spiral-shaped.