EP3567333A1 - Drive device for a cleaning device for a heat exchanger - Google Patents

Abstract

The invention relates to a drive device for a cleaning device (10) for a cylinder tube of a heat exchanger (13, 212). The drive device comprises a threaded spindle (3) which is adapted to be arranged in an axial direction (100) coaxially with the cylinder tube of the heat exchanger (13) in the cylinder tube and by rotation a cleaning element (12) in the cylinder tube along the axial direction (100) to move. Furthermore, the drive device has a coupling element (30, 210) with a first rotor (32) and a second rotor (34) coupled to the first rotor (32), the first rotor (32) mechanically rigid with the threaded spindle (3) and with the cylinder tube fluid-tight and / or pressure-tight connectable, and wherein the second rotor (34) with a drive element (208) is mechanically connectable such that the threaded spindle through the drive member (208) via the second rotor and the first rotor is rotatable , Furthermore, the invention relates to a cleaning device (10) and a heat exchanger (13).

Description

The invention relates to a drive device for a cleaning device for a heat exchanger, and a cleaning device and a heat exchanger with such a drive device. The invention is therefore particularly in the field of heat exchangers.

Heat exchangers for heating or for cooling a working medium are widely known from the prior art. Without restricting generality, the working medium natural gas will be considered in more detail below. Natural gas from soil reservoirs often has a particularly high percentage of unwanted accompanying substances and particularly high proportions of water. It is desirable to remove the impurities as well as the water content from the natural gas before it is used for further purposes. One possibility for this is the cooling of the natural gas in one or more steps to suitable low temperatures. In particular, in this case, a liquefaction of the natural gas may be appropriate.

During the cooling of natural gas, sediments on the heat transfer surfaces usually occur due to the aforementioned accompanying substances in the heat exchanger, the time course of such deposits depending on the operating conditions and the respective natural gas composition. The heat transfer surfaces must therefore be cleaned at certain intervals. For the reasons mentioned, however, it is difficult to specify generally valid cleaning intervals for the relevant heat exchangers.

Condensing and freezing impurities such as water, CO. as well as hydrocarbon compounds are deposited on the heat transfer surfaces and thus reduce the heat transfer. Even at operating temperatures above the freezing point of water, it may also come to the heat transfer surfaces to form methane hydrate.

Cylinder tubes of heat exchangers may for example be provided with a cleaning device, by means of which deposits of the Heat transfer surfaces can be removed mechanically in the cylinder tubes. For example, the DE 10 2015 010 455 A1 such a cleaning device.

However, such a cleaning device has the disadvantage that for the drive element, which is typically designed as an electric motor, an electrical wiring must be provided. Since the electric motor together with the cleaning device often has to be accommodated in a pressure-tight environment with the interior of the cylinder tube, therefore, typically a pressure-tight current feedthrough is necessary in order to be able to supply the drive element with electrical energy from an external energy source. This not only increases the production cost and thus the manufacturing cost, but also increases the maintenance and the risk of leaks in the heat exchanger system.

It is therefore the object of the present invention to provide a simplified and more reliable way of cleaning the cylinder tubes of heat collectors.

This object is achieved by a drive device, a cleaning device and a heat exchanger with the features of the respective independent claims. Preferred embodiments are the subject of the dependent claims and the following description.

In a first aspect, the invention relates to a drive device for a cleaning device for a cylinder tube of a heat exchanger. The drive device has a threaded spindle which is adapted to be arranged in an axial direction coaxially with the cylinder tube of the heat exchanger in the cylinder tube and to move by rotation a cleaning element in the cylinder tube along the axial direction. Furthermore, the drive device has a coupling element with a first rotor and a second rotor coupled to the first rotor, wherein the first rotor with the threaded spindle is mechanically rigid and fluid-tight and / or pressure-tight manner with the cylinder tube, and wherein the second rotor with a drive element is mechanically connectable such that the threaded spindle is rotatable by the drive element via the second rotor and the first rotor.

In another aspect, the invention relates to a cleaning device for a heat exchanger, comprising a drive device according to the invention, and a cleaning element which can be attached to the threaded spindle, that the cleaning element is displaceable by rotation of the threaded spindle in the axial direction through the cylinder tube.

In a further aspect, the invention relates to a heat exchanger, comprising at least one cylinder tube, wherein the at least one cylinder tube is equipped with a cleaning device according to the invention, and at least one drive element, which is mechanically connected to the second rotor of the at least one cleaning device that the second rotor can be driven by the drive element.

The fact that the first rotor can be connected to the cylinder tube in a fluid-tight and / or pressure-tight manner means that the first rotor can be connected to the cylinder tube in such a way that no fluid can penetrate between the first rotor and the cylinder tube and no fluid can flow through the first rotor can escape from the cylinder tube. If the first rotor is pressure-tightly connected to the cylinder tube, no fluid can penetrate between the first rotor and the cylinder tube or through the first rotor even if the fluid has a significant overpressure relative to the ambient pressure outside the cylinder tube and / or outside the first rotor For example, an overpressure of 10 bar, 20 bar, 50 bar or 100 bar.

The fact that the threaded spindle is rotatable or can be set in rotation means that the threaded spindle is rotatable about its longitudinal axis, which extends in the axial direction.

The invention has the advantage that by means of the coupling element, an efficient transmission of the driving force and / or a drive torque from the drive element to the threaded spindle and thus to the cleaning element can be transmitted without interruption and / or implementation by a delimitation or Shielding of a pressure area within the cylinder tube with respect to an outside area outside the Cylinder tube and / or outside of the first rotor is required. In other words, the preferably closed interior of the cylinder tube, when it is in communication with the first rotor, must not be made accessible in order to provide the driving force from the drive element to the first rotor. In this way, the manufacturing cost of the drive device can be reduced, whereby the manufacturing cost can be reduced.

Furthermore, the invention offers the advantage that bushings through a delimitation or wall, for example for supply lines, are not required, since the drive element according to the invention is not necessarily arranged in a pressure region which is in fluid communication with the interior of the cylinder tube got to. Rather, the drive element can be arranged outside this pressure range, where, for example, an ambient pressure prevails, which can be significantly lower than the pressure prevailing in the pressure region in the interior of the cylinder tube pressure. As a result, it is not absolutely necessary that the drive element is also designed for operation under high pressure. Rather, commercially available drive elements, such as commercially available electric motors, may be used, which are not necessarily suitable for operation under high pressure. As a result, the production costs can be further reduced.

In addition, the invention has the advantage that the risk of leaks can be reduced since it is possible to dispense with bushings which are conventionally required for connecting a power supply to a drive element arranged in the pressure region. As a result, on the one hand the maintenance effort can be reduced and on the other hand a susceptibility to errors or downtimes of the heat exchanger can be reduced.

Preferably, the second rotor is defined fluid-tight and / or pressure-tight from the first rotor. In other words, the first rotor and the second rotor are coupled to one another in such a way that there is no fluidic connection between the two. This offers the advantage that no fluid can penetrate to a coupling point between the first and the second rotor even if a higher or lower pressure prevails at the position of the first rotor than at the position of the second rotor. Particularly preferably, the first rotor and the second rotor are so separated fluid-tight from each other, that even with a large pressure difference no fluid can pass from the first rotor to the second rotor, or vice versa. This allows, for example, that the first rotor in the pressure region, which is in fluid communication with the interior of the cylinder tube, can be arranged, while the second rotor is arranged outside, for example at ambient pressure, or vice versa.

Preferably, the coupling element has a magnetic coupling, or is designed as such. This enables efficient coupling by means of magnetic forces, so that a mechanical connection between the first and the second rotor for power transmission is not necessarily required. This is particularly advantageous in that this allows a simple and / or efficient fluid-tight and / or pressure-tight demarcation between the first and the second rotor. Particularly preferably, the coupling element has a containment shell which delimits the first rotor and the second rotor in a fluid-tight and / or pressure-tight manner from one another. In this case, for example, the first rotor may be arranged within the containment shell, preferably on a side facing the cylinder tube and / or the threaded rod side of the coupling unit, while the second rotor is disposed outside of the split pot, preferably on a side facing away from the cylinder tube and / or the threaded rod side clutch unit. In this case, the first rotor and the second rotor can preferably be magnetically coupled through the gap pot. In this case, the coupling element is preferably designed such that a torque applied to the second rotor by the drive element is at least partially transferable to the first rotor. In other words, by driving the second rotor, the first rotor can be at least partially driven. The transmission of the driving force acting on the second rotor by the drive element or of the drive torque on the first rotor may be subject to slip.

Preferably, a heat exchanger has a plurality of cylinder tubes, each with a cleaning device. Particularly preferably, a heat exchanger has a plurality of drive elements. In particular, each cylinder tube of a heat exchanger may have its own cleaning device and preferably a drive element connected thereto. Alternatively, several cleaning devices can be driven by a drive unit.

Preferably, the heat exchanger comprises a control unit which is adapted to determine a position of the at least one cleaning element along the at least one threaded spindle and / or along the at least one cylinder tube in the axial direction and / or to control and / or at least one drive element to control that the at least one cleaning element occupies a predetermined position and / or performs a predetermined movement in the axial direction. The control unit may be integrated, for example, in the drive unit and / or in the drive element and / or in the cleaning device or be connected thereto. Preferably, each cleaning device and / or each drive element can be controlled and / or controlled by its own control unit, or a control unit can be designed to control and / or regulate a plurality of cleaning devices and / or drive elements.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is schematically illustrated by means of an embodiment in the drawings and will be described below with reference to the drawings.

• Figur 1 zeigt schematisch einen Längsschnitt durch eine Ausführungsform eines Wärmetauschers.
• Figur 2 zeigt in einer schematischen Darstellung ein Funktionsprinzip einer Regelung für eine Antriebsvorrichtung.

Brief description of the figures

• FIG. 1 shows schematically a longitudinal section through an embodiment of a heat exchanger.
• FIG. 2 shows a schematic representation of a principle of operation of a control for a drive device.

Detailed description of the figures

FIG. 1 schematically shows a longitudinal section through an embodiment of a heat exchanger 13, as it can be used in particular for cooling natural gas. In this simple embodiment, the heat exchanger 13 has an outer cylinder tube 1, which surrounds a cylinder tube, which is designed as a cooling coil 2. This cooling coil 2 has at least one, preferably spiral, channel 23 on its outer surface, which serves to guide a coolant. This channel 23 is generated by a corresponding helix 21 on the outer surface of the cooling coil 2. The inner surface of the hollow cylindrical cooling coil 2 has guide or profile grooves (not shown), which serve to guide a cleaning element 12, which is also referred to as a scraper. For example, the cleaning element 12 may be formed as an ice scraper.

The heat exchanger 13 has a cleaning device 10, which has a threaded spindle 3 located in the interior of the cooling coil 2 and extending in an axial direction 100. The threaded spindle 3 is driven via a first rotor 32, which is designed as an inner rotor, and is mounted in a bearing point, which is preferably designed as an axial / radial mixing bearing 5. At the other end of the threaded spindle 3, this can be stored in a radial bearing, which is preferably designed as a plain bearing bush (not shown). At the other end of the heat exchanger 13 may also be present a thermally decoupled condensate reservoir and a heating element for heating condensate in the condensate reservoir to melt the discharged through the cleaning element 12 there condensate and dissipate.

The first rotor 32 is formed as an inner rotor as part of a coupling element 30, which further comprises a second rotor 34, or as an outer rotor comprises. The coupling element 30 is designed as a magnetic coupling, so that the first rotor 32 and the second rotor 34 are separated from each other by a split pot 36 and coupled to each other via a magnetic force which is provided by the magnetic elements 38. This allows the rotor to be in fluid communication with the interior 2a of the cooling coil 2, while the second rotor 34 is disposed apart therefrom and may, for example, be exposed to ambient pressure. Thus, the first rotor 32 may be another The split pot is designed such that it can withstand a pressure difference between the interior 2a and the environment outside the cooling coil 2 and the second rotor 34 and that the first rotor 32 and the second rotor 34 can be coupled through the gap pot 36 via the magnetic elements 38. Thus, the second rotor 34 can be driven by a drive element (not shown) arranged outside the heat exchanger 13 or the cooling coil 2, the drive force being at least partially transmitted via the magnetic coupling to the first rotor 32 in order to rotate the threaded rod 3 and thereby to move the cleaning element 12.

By turning the second rotor 34, the threaded spindle 3 is thus set in rotation, so that the cleaning element 12 is displaced on the threaded spindle 3 along the cooling coil 2 in the axial direction. In the present example, a threaded spindle 3 is used for example with trapezoidal profile. A reversal of the direction of movement of the reamer 12 requires a reversal of the direction of rotation of the threaded spindle 3.

During operation of the heat exchanger 13, for example, moist, polluted working medium is introduced into the intermediate space between threaded spindle 3 and between cooling coil 2 or into the interior of the cylinder tube via a working medium inlet opening 14 on both sides and flows in the axial direction 100 to the working medium outlet opening (not shown) The working medium flows on the inner surface of the hollow cylindrical cooling coil 2 along the axial direction 100. Coolant is supplied to the space between the cooling coil 2 and the outer cylinder tube 1 via a coolant inlet opening 16 on both sides, the coolant being supplied to the other end of the heat exchanger 13 flows and leaves through the coolant outlet opening (not shown). In this case, the coolant flows spirally in the axial direction in the channel 23 formed between the outer cylindrical tube 1 and the cooling coil 2. The coolant removes heat from the cooling coil 2, which in turn removes heat from the working medium.

Due to the different pressure ratios between the cooling medium, for example nitrogen at a maximum of 10 bar, and the working medium, here CNG with impurities including nitrogen of 4 to 220 bar, and an ambient pressure of about 1 bar, nitrogen can be used as a companion at high pressure (For example, at 10 bar) caused by liquid nitrogen at low pressure (for example, at 1 bar), caused by the different pressure-dependent phase transitions to liquefy and deposited. The heat exchanger 13 proposed here can thus also be used for the liquefaction of nitrogen.

For the purpose of cleaning the heat transfer surfaces, for example of water or ice in the first stage or of higher hydrocarbons, CO ₂ and / or other impurities, the threaded spindle 3 is rotated by a drive element via the coupling element in rotation. The cleaning element 12, which engages in the thread of the threaded spindle 3, is thereby displaced in a translational movement in the axial direction. On its way in the axial direction, the cleaning element 12 takes with it the aforementioned condensed accompanying substances. These are pushed into the same upon reaching the condensate reservoir at the other end of the heat exchanger.

It should be noted that the heat exchanger 13 explained here can be adapted and used not only for natural gas liquefaction but also for a large number of industrial applications with appropriate working media. The cleaning device 10 and / or the cleaning element 12 can be adapted as a little complex replacement parts to the needs of the respective applications and quickly replaced in the event of damage.

FIG. 2 shows a schematic representation of a principle of operation of a controller 200 for a drive device or a cleaning device 10 or a heat exchanger 13. According to this embodiment, a control unit is provided, which may have, for example, a drive controller 202, which may be communicatively connected to a computing unit 204 and / or may be integrated with the arithmetic unit 204 in the control unit. The drive controller 202 is supplied by a power supply or power supply 206 with electrical energy or voltage. The power supply 206 is preferably designed to also provide the required electrical energy or voltage for the drive element 208, which may be designed as an electric motor. The drive controller 202 and / or the computing unit 204 calculates the electrical voltage applied to the drive element 208, For example, with the aid of stored characteristic data of the drive element, a resulting torque which is provided by the drive element 208 on the second rotor of the coupling element 210, which may be designed as a magnetic coupling. Furthermore, the drive controller 202 and / or the arithmetic unit 204 allow measuring or determining a rotational speed of the drive element 208 and thus a relative rotational angle of the drive motor, and optionally of the second rotor of the coupling element 210. The drive element 210 is connected to the coupling element 210, in particular with its second rotor, mechanically connected to transmit a driving force and / or a drive torque directly. The torque provided by the drive element 210 is thereby introduced into the second rotor of the coupling element and, preferably via the magnetic coupling, applied to the first rotor, which can constitute an inner rotor, and thus the threaded spindle of the heat exchanger 212. This torque transmission can be slip-related, ie that deviations can occur between the torque provided at the first rotor and the torque transmitted to the second rotor. According to previously determined characteristics of the drive element 208 and the coupling element 210, which are stored for example in the arithmetic unit 204, a ratio of torque to slip angle can be formed. Via a previously known thread pitch of the threaded spindle of the heat exchanger 212, the position of the cleaning element along the axial direction can then be determined and / or a change in position of a motor rotation of the drive element 208 can be assigned. The achievement of end positions of the cleaning element in the axial direction in the cylinder tube or along the threaded spindle can be determined for example via a first initiator 214 for the first end position and a second initiator 216 for the second end position.

According to a preferred embodiment, for example, the torque exerted by the drive element 208 on the second rotor of the coupling element 210, 40 Nm and a slip angle at the torque of 40 Nm 7 °. A thread pitch of the threaded spindle is 8 mm per thread turn according to this embodiment. At a relative rotation angle of 7200 ° since the departure from the first initiator 214 in the axial direction to the second initiator, the position of the cleaning element can be calculated as follows: (7200 ° -7 °) * 8mm / 360 ° = 159.84mm.

reference numeral

1

Outer cylinder tube

2

cooling coil

2a

Interior of the cooling coil

3

screw

5

Axial / radial mixing camp

10

cleaning device

12

cleaning element

13

heat exchangers

14

Working fluid inlet port

16

Coolant inlet opening

21

Spiral on the outer surface of the cooling coil

23

Channel of the cooling coil

30

coupling member

32

first rotor

34

second rotor

36

containment shell

38

magnetic elements

100

axial direction

200

Operation of the scheme

202

drive controller

204

computer unit

206

power supply

208

driving element

210

coupling member

212

heat exchangers

214

first initiator

216

second initiator

Claims (11)

Drive device for a cleaning device (10) for a cylinder tube of a heat exchanger (13, 212), the drive device comprising: - A threaded spindle (3) which is adapted to be arranged in an axial direction (100) coaxial with the cylinder tube of the heat exchanger (13) in the cylinder tube and by rotation a cleaning element (12) in the cylinder tube along the axial direction ( 100) to move; - A coupling element (30, 210) having a first rotor (32) and a second rotor (34) coupled to the first rotor (32), said first rotor (32) with the threaded spindle (3) mechanically rigid and with the cylinder tube fluid-tight and / or pressure-tight connectable, and wherein the second rotor (34) with a drive element (208) is mechanically connectable such that the threaded spindle through the drive element (208) via the second rotor and the first rotor is rotatable. Drive device according to claim 1, wherein the second rotor (32) fluid-tight and / or pressure-tight from the first rotor (34) is delimited. Drive device according to claim 1 or 2, wherein the coupling element (30, 210) comprises a magnetic coupling or is formed as such. Drive device according to claim 3, wherein the coupling element (30, 210) has a split pot (36) which defines the first rotor (32) and the second rotor (34) fluid-tight and / or pressure-tight from each other. Drive device according to claim 4, wherein the first rotor (32) and the second rotor (34) are magnetically coupled through the gap pot (36). Drive device according to one of the preceding claims, wherein the coupling element (30, 210) is designed such that a by the drive element (208) to the second rotor (34) acted upon torque is at least partially transferable to the first rotor (32). Cleaning device (10) for a heat exchanger (13), comprising: - A drive device according to one of the preceding claims; - A cleaning element (12) which in such a way on the threaded spindle (3) is attachable, that the cleaning element (12) by rotation of the threaded spindle (3) in the axial direction (100) is displaceable through the cylinder tube. Heat exchanger (13), comprising: - At least one cylinder tube, wherein the at least one cylinder tube is equipped with a cleaning device (10) according to claim 7; - At least one drive element (208) which is so mechanically connected to the second rotor (34) of the at least one cleaning device (10), that the second rotor (10) by the drive element (208) is drivable. Heat exchanger (13) according to claim 8, wherein the drive element (208) comprises an electric motor or is designed as such. Heat exchanger (13) according to claim 8 or 9, wherein the heat exchanger (13) comprises a plurality of cylinder tubes, each having a cleaning device (10) according to claim 7 and a plurality of drive elements (208). Heat exchanger (13) according to one of claims 8 to 10, further comprising a control unit which is adapted to a position of the at least one cleaning element (12) along the at least one threaded spindle (3) and / or along the at least one cylinder tube in the axial Direction (100) to determine and / or the at least one drive element (208) to control and / or regulate so that the at least one cleaning element (12) occupies a predetermined position in the axial direction (100) and / or a predetermined movement in the axial direction (100) performs.

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