GB2542217A

GB2542217A - A partition plate tightening element for a heat exchanger

Info

Publication number: GB2542217A
Application number: GB1603293.0A
Authority: GB
Inventors: Conrad Joachim
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2015-09-10
Filing date: 2016-02-25
Publication date: 2017-03-15
Also published as: GB201603293D0

Abstract

A partition plate tightening element 400 connects a head 100 of a heat exchanger 10 to a tubesheet 200. The tightening element is connected to a partition plate 110 of the head by a first solvable (separable) connection, and to the tubesheet by a second solvable connection. The tightening element tightens sections 111, 112 of the head divided by the partition plate. The tightening element may comprise a first sheet (411, fig 3) and a second sheet (412) parallel to each other and separated by a distance equal to the thickness of the partition plate. The length of the tightening element may be at least as large as a distance from a rim 103 of the head to a position up to which the partition plate extends inside the head, and its width may be equal to the inner diameter of the head or tubesheet. The tightening element may comprise first and second gaskets (431, 432). The solvable connections may be plug-in connections.

Description

Description A partition plate tightening element for a heat exchanger

The invention relates to a partition plate tightening element for a heat exchanger with a head and a tubesheet connectable with each other as well as to a corresponding heat exchanger.

Prior art

Heat exchangers can comprise a head or front end (so called channel or bonnet), a middle section (so called tubesheet) and a rear end. A plurality of tubes or pipes can be arranged inside the tubesheet. Head and tubesheet can be constructed separately from each other e.g. by means of flange connection. A first medium can for example be conducted into the heat exchanger by means of an inlet in the head and can be conducted through the tubes inside the tubesheet. The flow direction of the first medium can be reversed in the rear end and the first medium can be conducted again through the tubes towards the head. There, it can be conducted out of the heat exchanger by means of an outlet in the head. A second medium can be conducted through the tubesheet around the tubes, in order to perform a heat exchange between the first and second medium.

Since the first medium is usually conducted in two different flow directions through the head, the head can be divided in two separate sections by means of a so called partition plate. The head can also be divided in several sections by a plurality of partition plates, so that the first medium can pass several times through the head and through the tubesheet (so called mulita pass heat exchanger). For proper operation of the heat exchanger, the different sections of the head are tightened to prevent leakage of the medium between the sections.

It is desirable to provide means for a proper tightening of sections inside a head of a heat exchanger separated by partition plates.

Disclosure of the invention

The invention relates to a partition plate tightening element for a heat exchanger with a head and a tubesheet connectable with each other, and to a corresponding heat exchanger with the features of the independent claims. Further advantages and embodiments of the invention will become apparent from the description and the appended figures. Advantages and embodiments of the partition plate tightening element and the heat exchanger according to the invention arise from the following description in an analogous manner.

Head and tubesheet are particularly connectable via a separable connection, especially via flanges. Particularly, a rim of the head is connectable with a rim of the tubesheet. At least one partition plate is arranged inside the head, dividing the head into at least two sections. The partition plate can be fixated to the head, e.g. by welding. The partition plate tightening element is adapted to tighten sections of the head divided by the partition plate. For this purpose, the partition plate tightening element is adapted to be connected with the partition plate of the head via a first solvable connection and with the tubesheet via a second solvable connection.

It should be understood that the heat exchanger can comprise further elements, like a rear end, inlets, outlets, tubes, pipes, etc. Moreover, it is to be understood that the following description applies in analogous manner for heat exchangers with one partition plate as well as with several partition plates. Particularly, for each partition plate a separate partition plate tightening element is provided.

Advantages of the invention

The partition plate tightening element is particularly a replaceable element. Thus, according to the current conditions of the heat exchanger, an accordingly adapted partition plate tightening element can be used in order to guarantee proper tightening of the sections and a proper operation of the heat exchanger.

Head and tubesheet can for example be separated from each other for maintenance and/or repairs. By means of the partition plate tightening element, tightening of the head sections can easily be achieved when reconnecting the head and tubesheet.

Thus, maintenance and repairs can easily be conducted and the heat exchanger can afterwards easily be taken into operation again.

In conventional heat exchangers, the partition plate can, for example, be plugged into a groove in the tubesheet in order to provide tightening of the sections. For this purpose, conventional partition plates protrude beyond the rim of the head. However, positions close to the head rim can be covered by a partition plate of that kind and cannot be accessed for maintenance or repairs. Thus, in conventional heat exchangers, conventional partition plates possibly have to be removed at least partially in order to provide access to positions close to the head rim for maintenance or repairs. By means of the invention, this disadvantage can be overcome.

Since the partition plate tightening element can be separated from the heat exchanger by the solvable connections, easy access to positions of the heat exchanger during maintenance or repairs can be provided. Especially, positions close to the rims of the head or tubesheet are not covered by elements for support or tightening of the partition plate.

Due to high stresses and thermal loads, the partition plate can abrade and its length (in direction to a main axis of the heat exchanger) can reduce. In conventional heat exchangers with a partition plate being plugged into a groove in the tubesheet, the problem arises that the partition plate cannot be properly plugged into the corresponding groove without increasing attrition. Thus, tightening of the sections cannot be provided any more and expensive repairs have to be applied. However, by means of the invention, this disadvantage can also be overcome, since the partition plate tightening element can easily be replaced by a new one adapted to the current dimensions of the partition plate.

During operation of the heat exchanger, high temperature differences between an inlet and an outlet of a medium conducted through the heat exchanger can occur, leading to the high thermal loads and strains of the heat exchanger materials. Especially during a start-up of the heat exchanger high thermal stresses of the "cold" heat exchanger (usually having ambient temperature) and the comparatively high temperature medium conducted through the heat exchanger (up to several hundred degrees Celsius) can occur. This can lead to attrition of the partition plate as discussed above. Thus, the heat exchanger particularly needs to be maintained regularly, easily practicable by means of the invention.

Moreover, by means of the partition plate tightening element a revamp of the heat exchanger can be enabled. An old partition plate tightening element used before the revamp can be replaced by a new partition plate tightening element adapted to the new revamped design of the heat exchanger. Thus, no structural changes have to be applied to the heat exchanger to provide tightening of the sections after the revamp.

Advantageously, the at least one partition plate does not protrude beyond the rim of the head. Thus, the rim and positions close to the rim are not covered by the partition plate(s) and can easily be accessed for maintenance or repairs. Preferably, the at least one partition plate extends inside the head (in direction parallel to the main axis of the heat exchanger) up to a specific distance before the rim of the head. According to a particularly advantageous embodiment, a length of the partition plate tightening element (i.e. its dimension in direction parallel to the main axis of the heat exchanger) is preferably at least as large as this specific distance. Thus, the partition plate tightening element is particularly adapted to the length of the partition plate. A potential gap between the edge of the partition plate and the rim of the tubesheet is thus bridged by the partition plate tightening element. The partition plates can flexibly be constructed independently from the need of tightening, which is provided by the flexibly changeable partition plate tightening element.

According to an advantageous embodiment of the invention, the partition plate tightening element comprises a first and a second sheet parallel to each other. A distance between the first and the second sheet is essentially or exactly equal to a thickness of the partition plate. Thus, the sheets can especially be slipped on the partition plate. The length of the sheets is preferably at least as large as the specific distance from the head rim to the position up to which the partition plate extends. The space between the sheets can be hollow or at least partially be filled with an expedient material, e.g. a gasket material. The sheets can be made of an expedient material, e.g. of the same material as the head and/or tube sheet.

Preferably, a width of the partition plate tightening element (i.e. its dimension in direction perpendicular to the main axis of the heat exchanger), particularly a width of the first and the second sheet, is essentially or exactly equal to the inner diameter of the head and/or the tubesheet. Thus, proper tightening of the sections along the entire diameter of the head/ tubesheet is guaranteed.

According to a preferred embodiment, the partition plate tightening element comprises a first gasket and/or a second gasket. The first and/or the second gasket is/are preferably constructed as grooved metal gasket. The first gasket is preferably adapted to tighten the first solvable connection between the partition plate tightening element and the partition plate. Particularly, the first gasket is arranged between the first and second sheet and forms a contact surface of the partition plate tightening element with the partition plate. The second gasket is preferably adapted to tighten the second solvable connection between the partition plate tightening element and the tubesheet. Particularly, the second gasket forms a contact surface of the partition plate tightening element with the tubesheet.

Advantageously, the first and/or the second solvable connection is/are a plug-in connection. Thus, the partition plate tightening element can easily be plugged into the tubesheet and the head when connecting tubesheet and heat with each other. Also, the partition plate tightening element can easily be removed or replaced when separating tubesheet and head without any technical effort. The partition plate tightening element is preferably adapted to be slipped on the partition plate, particularly via the first and second sheet. Preferably, the partition plate tightening element is adapted to be plugged into a partition plate support element arranged at the tubesheet. This partition plate support element can, for example, be constructed as a groove in the tubesheet or as a rail arranged on the tubesheet.

Advantageously, the heat exchanger comprises a first flange arranged at the head, particularly at the rim of the head, and a second flange arranged at the tubesheet, particularly at the rim of the tubesheet. By means of the flanges, the head and the tubesheet are preferably connectable with each other via a separable connection.

According to a preferred embodiment, the heat exchanger comprises a weld ring gasket, wherein a first part of the weld ring gasket is welded to the rim of the head, preferably to the first flange, and a second part of the weld ring gasket is welded to a rim of the tubesheet, preferably to the second flange. By means of the weld ring gasket, leakage between the head and the tubesheet, particularly of the flange connection, is prevented.

Due to the temperature differences during start-up and operation of the heat exchanger, high thermal loads and strains of the weld ring gasket can occur. The weld ring gasket and the head/tubesheet are usually made of different materials. For example, the head and the tubesheet can be made of chromium-molybdenum steel whereas the weld ring gasket can be made of stainless steel. Since these different materials behave differently when exposed to high temperatures (particularly since they expand differently), huge stresses of the weld ring gasket can occur, particularly huge stresses of the welded joint between weld ring gasket and head/tubesheet. Thus, the weld ring gasket, particularly the corresponding welded joint, needs to be maintained regularly to prevent leakage between head and tubesheet, easily practicable by means of the invention.

As discussed above, the partition plate preferably extends up to a specific distance before the rim of the head. Thus, the rim and positons close to the rim are preferably not covered by the partition plate and can easily be accessed for maintenance or repairs without the need to remove the partition plate or parts of it. The at least one partition plate advantageously extends inside the head to a position before the weld seam of the welded joint. Thus, the weld seam can easily be accessed for maintenance or repairs. Moreover, the first part of the weld ring gasket can easily be removed and replaced if necessary, and new first part of the weld ring gasket can easily be welded to the head rim.

The heat exchanger is preferably a TEMA heat exchanger according to the standards of the TEMA (Tubular Exchanger Manufacturers Association), preferably a shell-and-tube heat exchanger. Head, tubesheet and rear end of the heat exchanger can expediently be constructed according to TEMA standards. For example, the head can be constructed as a so called Type A head (channel wit removable cover) or as a Type B head (bonnet with integral cover). The tubesheet can e.g. be constructed as type E tubesheet (obe pass shell) or as a Type F tubesheet (two pass shell with longitudinal baffle). The heat exchanger can, for example, be used in a hydrogen plant for hydrogen production.

It should be noted that the previously mentioned features and the features to be further described in the following are usable not only in the respectively indicated combination, but also in further combinations or taken alone, without departing from the scope of the present invention.

The present invention will now be described further, by way of example, with reference to the accompanying drawings, in which FIG. 1 schematically shows a preferred embodiment of a heat exchanger according to the invention in a side view. FIG. 2 schematically shows a part of a preferred embodiment of a heat exchanger according to the invention in a side view. FIG. 3 schematically shows a preferred embodiment of a partition plate tightening element according to the invention in a side view. FIG. 4 schematically shows a part of a preferred embodiment of a heat exchanger according to the invention with a head and a tubesheet separated from each other in a side view. FIG. 5 schematically shows part of a head of a preferred embodiment of a heat exchanger according to the invention.

Detailed description

In FIG. 1 a preferred embodiment of a heat exchanger 10 according to the invention in form of a shell-and-tube heat exchanger is schematically shown in a sectional side view. The shell-and-tube heat exchanger 10 is especially a TEMA heat exchanger, i.e. constructed according to the standards of the TEMA (Tubular Exchanger Manufacturers Association).

The heat exchanger 10 comprises a front end or head 100, a tubesheet 200, and a rear end 300. In this particular example of FIG. 1, the heat exchanger 10 is shown as a Type BEM heat exchanger according to TEMA standards, with a Type B head 100, a

Type E tubesheet 200, and a type M rear end 300. Head 100, tubesheet 200, and rear end 300 are for example made of chromium-molybdenum steel.

The head 100 comprises an inlet 101 and an outlet 102. A partition plate 110 is arranged inside the head 100 and divides the head 100 into two sections 111 and 112. The partition plate 110 can for example also be made of chromium-molybdenum steel. The tubesheet 200 also comprises an inlet 201 and an outlet 202, as well as a plurality of tubes 210 arranged inside the tubesheet 200. A first number 211 of tubes 210 is provided for a flow of a medium in a first flow direction and a second number 212 of tubes 210 is provided for a flow of a medium in a second flow direction, reversed to the first flow direction. For reasons of simplification, two tubes are shown in FIG. 1, but the tubesheet can comprise an expedient amount of tubes 210. A first flange 120 is arranged at a rim 103 of the head 100 and a second flange 220 is arranged at a rim 203 of the tubesheet 200. By means of the first flange 120 and the second flange 220 the head 100 and the tubesheet 200 are connectable with each other via a separable flange connection. A first medium can be conducted into section 111 of the head 100 via inlet 101. From there, the first medium is conducted through the first number 211 of tubes 210 in the first flow direction towards the rear end 300. The flow of the medium is reversed in a cavity 301 of the rear end 300 and the first medium is conducted through the second number 212 of tubes 210 in the second flow direction into the second section 112 of the head 100. The first medium is conducted out of the head 100 through the outlet 102. A second medium can be conducted into the tubesheet 200 via inlet 201, through the tubesheet 200 around the tubes 210, in order to perform a heat exchange between the first and second medium, and out of the tubeshet 200 via outlet 202.

In FIG. 2 the head 100 and a part of the tubesheet 200 of the heat exchanger 10 according to FIG. 1 are schematically shown in a sectional side view. Identical reference figures in the drawings refer to identically constructed elements.

As can be seen in FIG. 2 the heat exchanger comprises a weld ring gasket. A first part 130 of this weld ring gasket is welded to the rim 103 of the head, particularly to the first flange 120, and a second part 230 of the weld ring gasket is welded to the rim 203 of the tubesheet 200, particularly to the second flange 220. When the head 100 and the tubesheet 200 are connected with each other, the first and second part 130 and 230 of the weld ring gasket are also welded with each other in order to prevent leakage of the flange connection and leakage between head 100 and tubesheet 200.

In order to prevent leakage between the sections 111 and 112 and to tighten the partition plate, a preferred embodiment of a partition plate tightening element 400 according to the invention is connected with the partition plate 110 and with the tubesheet 200.

Section A, represented by a dashed-dotted circle in FIG. 2, is shown more detailed in FIG. 3. As can be seen in FIG. 3, the partition plate tightening element 400 comprises a first sheet 411 and a second sheet 412 parallel to each other, for example made of stainless steel. A distance between the first and the second sheet 411 and 412 is equal to a thickness of the partition plate 110. A fist part 413 of the space between the first and the second sheet 411 and 412 is filled with a material, e.g. also stainless steel; a second part 414 is a cavity. A first gasket 431 in form of a grooved metal gasket is arranged between the first and the second sheet 411 and 412.

The partition plate tightening element 400 can be slipped onto the partition plate 110 up to the first gasket 431. Thus, the partition plate tightening element 400 is connectable with the partition plate 110 via a first solvable connection in form of a plug-in connection. This first solvable connection is tightened by means of the first gasket 431. A partition plate support element in form of a first rail 421 and a second rail 422 is arranged at the rim 203 of the tubesheet 200. The partition plate tightening element 400 can be plugged into or slid in-between these rails 421 and 422. Thus, the partition plate tightening element 400 is connectable with the tubesheet 200 via a second solvable connection, e.g. in form of a plug-in connection. The partition plate support element 400 comprises a second gasket 432 in form of a grooved metal gasket in order to tighten this second solvable connection.

In FIG. 4 the heat exchanger 10 is schematically shown analogously to FIG. 2, but with the head 100 and the tubesheet 200 separated from each other. The partition plate tightening element 400 is detached from the head 100 and the tubesheet 200. With head 100 and tubesheet 200 separated from each other and with the detached partition plate tightening element 400, maintenance and/or repairs of the heat exchanger can be performed. Particularly, a weld seam of the connection between the first part 130 of the weld ring gasket and the first flange 120 can easily be maintained or repaired.

In FIG. 5 a part of the head 100 separated from the tubesheet 200 is schematically shown. Partition plate 110 is shown in FIG. 5 in top view. As can be seen in FIG. 4 and FIG. 5, the partition plate 110 does not protrude beyond the rim 103 of the head 100. Inside the head 100 the partition plate 110 extends up to a specific distance D before the rim 103 of the head 100. The length of the partition plate tightening element 400, particularly the length of the first and second sheet 411 and 412 is at least as large as this specific distance D.

The partition plate 110 extends inside the head to a position before the weld seam 131 of the welded joint between the first part 130 of the weld ring gasket and the first flange 120. The weld seam 131 is thus not covered by the partition plate 110 and can easily be maintained or repaired.

Reference list 10 heat exchanger, shell-and-tube heat exchanger, TEMA heat exchanger 100 head 101 inlet 102 outlet 103 rim of the head D distance before the rim of the head 110 partition plate 111 section of the head 112 section of the head 120 first flange 130 weld ring gasket, first part of the weld ring gasket 131 weld seam 200 tubesheet 201 inlet 202 outlet 203 rim of the tubesheet 210 tubes 211 first number of tubes 212 second number of tubes 220 second flange 230 weld ring gasket, second part of the weld ring gasket 300 rear end 301 cavity 400 partition plate tightening element 411 first sheet 412 second sheet 413 first part of the space between the first and second sheet 414 second part of the space between the first and second sheet 421 partition plate support element, first rail 422 partition plate support element, second rail 431 first gasket, grooved metal gasket 432 second gasket, grooved metal gasket

Claims

1. A partition plate tightening element (400) for a heat exchanger (10) with a head (100) and a tubesheet (200) connectable with each other, said partition plate tightening element being - adapted to be connected with a partition plate (110) of the head (100) via a first solvable connection and with the tubesheet (200) via a second solvable connection, and adapted to tighten sections (111, 112) of the head (100) divided by the partition plate (110).

2. The partition plate tightening element (400) according to claim 1, wherein a length of the partition plate tightening element (400) is at least as large as a specific distance (D) from a rim (103) of the head (100) to a position up to which the partition plate (110) extends inside the head (100).

3. The partition plate tightening element (400) according to claim 1 or 2, comprising a first sheet (411) and a second sheet (412) parallel to each other, wherein a distance between the first sheet (411) and the second sheet (412) is essentially or equal to a thickness of the partition plate (110).

4. The partition plate tightening element (400) according to any one of the preceding claims, wherein a width of the partition plate tightening element (400) is essentially or exactly equal to the inner diameter of the head (100) and/or the tubesheet (200).

5. The partition plate tightening element (400) according to any one of the preceding claims, comprising a first gasket (431), preferably a grooved metal gasket, adapted to tighten the first solvable connection between the partition plate tightening element (400) and the partition plate (110) and/or a second gasket (432), preferably a grooved metal gasket, adapted to tighten the second solvable connection between the partition plate tightening element (400) and the tubesheet (200).

6. The partition plate tightening element (400) according to any one of the preceding claims, wherein the first solvable connection and/or the second solvable connection is a plug-in connection.

7. The partition plate tightening element (400) according to any one of the preceding claims, adapted to be slipped on the partition plate (110).

8. The partition plate tightening element (400) according to any one of the preceding claims, adapted to be plugged into a partition plate support element (421,422) arranged at the tubesheet (200).

9. A heat exchanger (10), comprising a head (100) and a tubesheet (200) connectable with each other, at least one partition plate (110) dividing the head (100) into at least two sections (111, 112), and at least one partition plate tightening element (400) according to any one of the preceding claims.

10. The heat exchanger (10) according to claim 9, wherein the at least one partition plate (110) does not protrude beyond a rim (103) of the head (100).

11. The heat exchanger (10) according to claim 9 or 10, wherein the at least one partition plate (110) extends inside the head (100) up to a specific distance (D) before the rim of the head and wherein a length of the partition plate tightening element (400) is at least as large as the specific distance (D).

12. The heat exchanger (10) according to any one of the claims 9 to 11, further comprising a first flange (120) arranged at the head (100), particularly at the rim (103) of the head (100), and a second flange (220) arranged at the tubesheet (200), particularly at the rim (203) of the tubesheet (200), wherein the head (100) and the tubesheet (200) are connectable with each other via the first and second flanges (120, 220).

13. The heat exchanger according to any one of the claims 9 to 12, further comprising a weld ring gasket, wherein a first part (130) of the weld ring gasket is welded to the rim (103) of the head (100) and a second part (230) of the weld ring gasket is welded to a rim (203) of the tubesheet (200).

14. The heat exchanger (10) according to claim 13, wherein the at least one partition plate (110) extends inside the head (100) to a position before a weld seam (131) of the welded joint between the weld ring gasket and the rim (103) of the head (100).