CN210741574U

CN210741574U - RD wedge-shaped flowmeter with heat preservation jacket

Info

Publication number: CN210741574U
Application number: CN201922144659.5U
Authority: CN
Inventors: 王乐; 朱红斌; 朱萍萍
Original assignee: Anwei Electromechanical Equipment Manufacturing Shanghai Co Ltd
Current assignee: Anwei Electromechanical Equipment Manufacturing Shanghai Co Ltd
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2020-06-12
Anticipated expiration: 2029-12-02

Abstract

The utility model relates to a RD wedge flowmeter with heat preservation presss from both sides cover, it includes the flow tube, and each rigid coupling in the both ends of flow tube has a ring flange, and the perpendicular intercommunication of length direction of flow tube outer peripheral face flow tube has two connecting pipes, and the one end that the flow tube was kept away from to the connecting pipe is provided with the pressure gauge, and the flow tube is intraductal still to be provided with a wedge throttle, and flow tube outer peripheral face cover is equipped with a heat preservation shell, and the heat preservation shell includes the first casing and the second casing of two mutual locks, and the both ends of heat preservation shell are pushed up respectively and are touched on the ring flange at flow tube both ends, set up first heat tracing medium hole on the first casing, seted up second heat tracing medium hole on the second casing, still be provided with in the heat preservation shell one and be used for leading the guide plate that water vapour regularly flowed in the heat tracing layer.

Description

RD wedge-shaped flowmeter with heat preservation jacket

Technical Field

The utility model belongs to the technical field of fluid measurement's technique and specifically relates to a RD wedge flowmeter with heat preservation clamp cover is related to.

Background

The wedge-shaped flowmeter is a differential pressure type flow meter, the measurement principle of the wedge-shaped flowmeter is completely the same as that of other differential pressure type flow meters, and the wedge-shaped flowmeter is a flow measurement method based on a Bernoulli equation and a flow continuity equation. The traditional differential pressure type instrument changes the mode of throttling in the center of a pipeline, and a wedge-shaped throttling device is added into the pipeline instead. It can measure gas, liquid and steam, and is suitable for measuring high-viscosity fluid and dirty fluid, and when the viscosity is up to 500MPa.s, it can still make high-precision measurement. The method is widely measured in industries such as petrifaction, steel, oil refining and the like.

As shown in FIG. 1, the wedge-shaped flowmeter comprises a measuring pipe 6 for accommodating the flow of fluid, two pressure-taking pipes 61 are communicated with the outer peripheral surface of the measuring pipe 6 along the length direction of the measuring pipe 6, and a pressure gauge 13 for measuring the fluid pressure at the pressure-taking pipes 61 is arranged on the pressure-taking pipes 61. A wedge-shaped throttling piece 14 with a triangular cross section is further fixedly connected between the two pressure taking pipes 61 in the measuring pipe 6, the end angle of the wedge-shaped throttling piece 14 is arranged away from the pressure taking pipes 61, pressure of fluid passing through the wedge-shaped throttling piece 14 is changed, so that pressure difference is obtained through the pressure gauges 13 on the two sides of the wedge-shaped throttling piece 14, and the flow of the fluid flowing through the measuring pipe 6 is calculated according to the Bernoulli equation.

In some special industries and special fluid measurement, the temperature is always kept unchanged during measurement, if the measurement temperature is reduced along with the fluid flowing for a period of time, the viscosity of the fluid is changed, meanwhile, the temperature is reduced too much, the fluid is subjected to physical phenomena such as solidification and crystallization, the measurement cannot be carried out, and the instrument is seriously scrapped. The existing heat preservation technology is usually used for packaging heat preservation cotton on a measured process pipeline, but the temperature reduction speed can be only reduced in the process, and the temperature of the measured fluid cannot be fundamentally maintained.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a RD wedge flowmeter with heat preservation cover, it has the effect that can keep warm to being surveyed the fluid.

The above utility model discloses an above-mentioned utility model's purpose can be realized through following technical scheme:

an RD wedge-shaped flowmeter with a heat-insulating jacket comprises a flow tube, wherein two flanges are fixedly connected to two ends of the flow tube respectively, two connecting pipes are vertically communicated with the outer peripheral surface of the flow tube along the length direction of the flow tube, a pressure gauge is arranged at one end of each connecting pipe far away from the flow tube, a wedge-shaped throttling element is further arranged in the flow tube and positioned between the two connecting pipes, the flow tube outer peripheral face is sleeved with a heat preservation shell, a heat tracing layer is formed in a gap between the heat preservation shell and the flow tube outer peripheral face, the heat preservation shell comprises a first shell and a second shell which are mutually buckled, a first connecting plate is fixedly connected to the end portions, facing one side of the connecting pipe, of the first shell and the end portion, facing away from the connecting pipe, of the second shell, a second connecting plate is fixedly connected to the end portions, facing away from the connecting pipe, of the first shell and the end portion, and after the first shell and the second shell are mutually buckled, the two first connecting plates and the two second connecting plates are fixed through bolts and nuts respectively.

Two ends of the heat preservation shell are respectively abutted against flange plates at two ends of the flow tube, a first heat tracing medium hole for introducing a heat tracing medium into a heat tracing layer is formed in the first shell, a second heat tracing medium hole for accommodating the outflow of the heat tracing medium is formed in the corresponding second shell, and the first heat tracing medium hole and the second heat tracing medium hole are respectively positioned at two ends of the flow tube in the length direction; the heat tracing layer is also internally provided with a guide plate for guiding the water vapor to flow regularly in the heat tracing layer, and the guide plate is spirally arranged on the peripheral surface of the flow pipe along the length direction of the flow pipe.

By adopting the technical scheme, when fluid flows through the flow tube, the fluid passes through the wedge-shaped throttling element and is limited by the wedge-shaped throttling element, so that the flow velocity of the fluid is increased, the pressure is reduced, the fluid pressures on two sides of the wedge-shaped throttling element can be measured respectively at the moment, the pressure difference is read, and the flow of the fluid in the flow tube can be calculated through the Bernoulli equation. When the flow tube measures some fluid needing heat preservation, workers can wind the guide plate on the peripheral surface of the flow tube, the outer side of the guide plate is buckled with a first shell and a second shell, bolts and nuts are respectively penetrated through the first connecting plate and the second connecting plate, thereby fixing the first shell and the second shell on the peripheral surface of the flow tube, at the moment, a worker can introduce heat tracing media for heat preservation into the first heat tracing media hole, the heat tracing media are mutually contacted with the outer wall of the flow tube, thereby preserving the heat of the fluid in the flow tube, leading the heat tracing medium to be in uniform contact with the peripheral surface of the flow tube after being guided by the guide plate, and flows out of the second heat tracing medium holes, thereby reducing heat loss when the fluid flows from the flow tube, further, the deterioration of the fluid quality due to the temperature decrease or the clogging of the flow tube by crystals can be reduced.

The present invention may be further configured in a preferred embodiment as: the one side rigid coupling of ring flange towards the heat preservation shell has a cross-section to be the card strip of L type, and the one end of card strip and the perpendicular rigid coupling in surface of ring flange, the one end that the ring flange was kept away from to the card strip deviate from the flow tube setting, correspond all offer on first casing and the second casing with card strip complex draw-in groove.

Through adopting above-mentioned technical scheme, through mutually supporting of card strip and draw-in groove, can be on the one hand to first casing, second casing and flow tube position reciprocal anchorage, on the other hand can strengthen the leakproofness between heat preservation shell and the ring flange to the condition emergence of revealing in the gap between ring flange and the heat preservation shell has been reduced to vapor.

The present invention may be further configured in a preferred embodiment as: and one end of the clamping strip, which is far away from the flange plate, is fixedly connected with an isolating strip.

Through adopting above-mentioned technical scheme, detain when the draw-in groove and establish on card strip terminal surface to during the extrusion parting bead, the parting bead takes place deformation and then can fill the gap between draw-in groove and the card strip, thereby further improved the leakproofness between heat preservation shell and the ring flange.

The present invention may be further configured in a preferred embodiment as: the end face of the first shell facing the second shell is provided with a buckling groove, and a buckling strip which can be clamped into the buckling groove is fixedly connected to the end face corresponding to the second shell.

Through adopting above-mentioned technical scheme, the lock strip card is gone into the lock inslot to the convenience when having improved first casing and second casing counterpoint, and can be with first casing and second casing reciprocal anchorage, thereby stability when having improved first casing and second casing lock.

The present invention may be further configured in a preferred embodiment as: a rubber pad is further arranged between the two first connecting plates, and a rubber pad is also arranged between the two corresponding second connecting plates.

Through adopting above-mentioned technical scheme, the setting of rubber pad is twisted when bolt and nut each other to make first connecting plate or second connecting plate closely paste and lean on the back, the rubber pad is extruded, and fills the gap of junction, and then has improved the leakproofness of first casing with the second casing junction.

The present invention may be further configured in a preferred embodiment as: the inner peripheral surfaces of the first shell and the second shell are provided with clamping grooves which are used for accommodating the guide plate and clamping and fixing the guide plate.

Through adopting above-mentioned technical scheme, the guide plate card is gone into corresponding screens inslot after first casing and the mutual lock of second casing to improved the guide plate on the one hand and to the spaced leakproofness of heat tracing layer, on the other hand screens groove can be fixed the guide plate screens, thereby improved the stability of guide plate during operation.

The present invention may be further configured in a preferred embodiment as: after the first shell and the second shell are buckled with each other, the first heat tracing medium hole and the second heat tracing medium hole are arranged back to back.

By adopting the technical scheme, when the heat tracing medium flows into the heat tracing layer from the first heat tracing medium hole on the outer peripheral surface close to one end of the flow tube, the heat tracing medium can be fully contacted with the outer peripheral surface of the flow tube and is discharged from the second heat tracing medium hole close to the other end of the flow tube, so that the heat preservation efficiency of the heat tracing medium on the flow tube is improved.

The present invention may be further configured in a preferred embodiment as: the outer peripheral face of the heat preservation shell is further sleeved with a heat insulation layer made of rubber materials, and heat insulation cotton is filled between the heat insulation layer and the heat preservation shell.

Through adopting above-mentioned technical scheme, through thermal-insulated cotton with the thermal-insulated effect of heat insulation layer to further improved the heat preservation effect of flow tube, and heat insulation layer and thermal-insulated cotton setting can also protect the staff, reduce the condition emergence that the staff is scalded by the heat preservation shell.

To sum up, the utility model discloses a following at least one useful technological effect:

1. the heat insulation performance of the peripheral surface of the flow tube is improved; through the arrangement of the heat preservation shell, the heat tracing medium in the heat tracing layer can preserve heat of the outer peripheral surface of the flow tube, so that the temperature reduction of fluid after passing through the flow tube is reduced;

2. the safety of the RD wedge-shaped flow meter with the heat-preservation jacket in use is improved; through the setting of heat insulation layer and thermal-insulated cotton, it takes place to have reduced the condition that the staff mistake is scalded after touching the heat preservation shell outer peripheral face.

Drawings

FIG. 1 is a schematic diagram of a prior art wedge-shaped flowmeter;

FIG. 2 is a schematic diagram of the overall structure of an RD wedge flow meter with a thermal jacket;

FIG. 3 is a schematic view showing the structure of the thermal insulating case;

FIG. 4 is an exploded view showing the connection relationship of the insulating cases;

FIG. 5 is a schematic structural view showing the mating relationship between the card strip and the card slot;

FIG. 6 is a cross-sectional view of an internal structure embodying an RD wedge flow meter with a thermal jacket;

FIG. 7 is an enlarged view of detail A of FIG. 6;

fig. 8 is a schematic view showing the structure of the sealing strip and the sealing groove.

In the figure, 1, a flow tube; 11. a connecting pipe; 111. a sealing strip; 13. a pressure gauge; 14. a wedge-shaped orifice; 2. a flange plate; 21. clamping the strip; 211. a spacer bar; 3. a heat preservation shell; 31. a first housing; 311. a first heat trace medium hole; 312. buckling the groove; 32. a second housing; 321. a second heat tracing medium hole; 322. a fastening strip; 33. accommodating grooves; 331. a sealing groove; 34. a first connecting plate; 35. a second connecting plate; 38. a card slot; 39. a rubber pad; 4. heat tracing layer; 41. a baffle; 42. a clamping groove; 5. a heat insulating layer; 51. heat insulation cotton; 6. a measurement tube; 61. and (6) a pressure tapping pipe.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 2 and fig. 3, for the utility model discloses a RD wedge flowmeter with heat preservation presss from both sides cover, including flow tube 1, each rigid coupling in flow tube 1's both ends has one and the flange dish 2 of the pipe connection that awaits measuring, flow tube 1's outer peripheral face perpendicular to flow tube 1's axis direction rigid coupling has connecting pipe 11, and connecting pipe 11 and flow tube 1 are inside to communicate each other, the tip intercommunication that flow tube 1 was kept away from to connecting pipe 11 has a pressure gauge 13, pressure gauge 13 passes through flange joint with connecting pipe 11, connecting pipe 11 border flow tube 1's length direction is provided with two, and two connecting pipes 11 are located flow tube 1's homonymy. A wedge-shaped throttling element 14 (see fig. 6) is further arranged in the flow tube 1, the wedge-shaped throttling element 14 is positioned between the two pressure gauges 13, and the wedge-shaped throttling element 14 is fixedly connected with the inner circumferential surface of the flow tube 1 on the side where the connecting pipe 11 is fixedly connected, so that the two pressure gauges 13 can respectively measure the pressure change of the fluid before throttling and after throttling, and the flow rate of the fluid passing through the flowmeter can be calculated through the bernoulli equation.

As shown in fig. 4 and 5, when the flow meter is measuring some temperature-sensitive fluids, the flow meter needs to be thermally insulated. The outer peripheral face cover of flowmeter is equipped with a heat preservation shell 3, and heat preservation shell 3 is including detaining each other and establishing first casing 31 and the second casing 32 at flow tube 1 outer peripheral face, and the cross-section of first casing 31 and second casing 32 is semicircle annular to the holding tank 33 that is used for holding connecting pipe 11 is seted up at the border of first casing 31 and second casing 32. The first shell 31, the second shell 32 is fixed with a first connecting plate 34 on the outer peripheral surface of the end part close to the connecting pipe 11, and the two first connecting plates 34 are arranged in parallel; the outer peripheries of the end parts of the first shell 31 and the second shell 32 far away from the connecting pipe 11 are respectively fixedly connected with a second connecting plate 35, and the two second connecting plates 35 are arranged in parallel; the two first connecting plates 34 are provided with bolts and nuts for attaching the two first connecting plates 34 to each other, and the second connecting plate 35 is also provided in the same manner. The first housing 31 and the second housing 32 are fastened and fixed to each other by the mutual engagement of the bolt and the nut. The inner space formed by the first case 31 and the second case 32 after being fastened is a cylinder, and the diameter of the cross-sectional circle of the cylinder is larger than the outer diameter of the flow tube 1, so that a heat-tracing layer 4 is formed between the first case 31, the second case 32 and the flow tube 1. The end parts of the first shell 31 and the shell 32 are respectively abutted against the flange plates 2 at two ends of the flow tube 1, one surface of the corresponding flange plate 2 facing the heat preservation shell 3 is also provided with an annular clamping strip 21, the section of the clamping strip 21 is L-shaped, one end of the clamping strip 21 is vertically and fixedly connected with the surface of the flange plate 2, and the other end of the clamping strip 21 is bent along the direction departing from the flow tube 1; a slot 38 matched with the clamping strip 21 is formed on the inner peripheral surface of the first shell 31 and the second shell 32. After the first shell 31 and the second shell 32 are fastened with each other, the clamping strip 21 is clamped into the clamping groove 38, so that the sealing performance of the heat tracing layer 4 is enhanced. One end of the clamping strip 21, which is far away from the flange 2, is fixedly connected with a rubber isolation strip 211, and after the first shell 31 and the second shell 32 are buckled with each other, the isolation strip 211 is pushed into the bottom surface of the sealing groove 331 and tightly attached to the bottom surface of the sealing groove 331, so that the sealing property between the heat preservation shell 3 and the flange 2 is further strengthened.

As shown in fig. 6 and 7, the end surface of the first casing 31 contacting with the second casing 32 is provided with a fastening groove 312, the end surface of the second casing 32 contacting with the first casing 31 is fixedly connected with a fastening strip 322 matching with the fastening groove 312, the inner circumferential surface of the accommodating groove 33 is provided with a sealing groove 331 (shown in fig. 8), and the outer circumferential surface of the connecting tube 11 is fixedly connected with a sealing strip 111 (shown in fig. 8) capable of being clamped into the sealing groove 331. After the first case 31 and the second case 32 are fastened to each other, the sealing strip 111 is clamped into the sealing groove 331, the fastening strip 322 is clamped into the fastening groove 312, and the positions of the first case 31, the second case 32 and the flow tube 1 can be relatively fixed by the mutual fit between the sealing strip 111 and the sealing groove 331, and the sealing performance between the first case 31, the second case 32 and the connecting tube 11 is improved. The engagement grooves 312 and the engagement strips 322 cooperate with each other, so that the sealing performance of the engagement between the first shell 31 and the second shell 32 is improved. A rubber pad 39 is further arranged between the two first connecting plates 34, and a rubber pad 39 is also arranged between the two second connecting plates 35, so that when the first shell 31 and the second shell 32 are buckled with each other and fixed with each other through the fixing bolt and the fixing nut, the rubber pad 39 is extruded, and the sealing performance of the joint of the first shell 31 and the second shell 32 is improved.

As shown in fig. 3 and 4, the first case 31 is provided with a first heat tracing medium hole 311, the second case 32 is provided with a second heat tracing medium hole 321, the first heat tracing medium hole 311 and the second heat tracing medium hole 321 are oppositely arranged opposite to the flow tube 1 and are respectively located on the outer peripheral surfaces of the flow tube 1 near the two ends, and the first heat tracing medium hole 311 and the second heat tracing medium hole 321 are both communicated with the heat tracing layer 4. The first heat trace medium holes 311 can be filled with heat trace medium for heat preservation (in this embodiment, the heat trace medium is set to be steam), and the heat trace medium flows in the heat trace layer 4 and flows out of the second heat trace medium holes 321. In order to make the heat tracing medium flow more regularly in the heat tracing layer 4, a guide plate 41 is further arranged in the heat tracing layer 4, the guide plate 41 is spirally arranged on the outer peripheral surface of the flow pipe 1 along the length direction of the flow pipe 1, a clamping groove 42 for accommodating the side wall of the guide plate 41 is formed in the inner peripheral surfaces of the first shell 31 and the second shell 32, and the guide plate 41 is clamped into the corresponding clamping groove 42 after the first shell 31 and the second shell 32 are mutually buckled, so that on one hand, the sealing performance of the guide plate 41 on the heat tracing layer 4 is improved, on the other hand, the clamping groove 42 can clamp and fix the guide plate 41, and the stability of the guide plate 41 during operation is improved.

As shown in fig. 6, the outer circumferential surface of the thermal insulation case 3 is further sleeved with a thermal insulation layer 5, thermal insulation cotton 51 is filled between the thermal insulation layer 5 and the thermal insulation case 3, the thermal insulation effect of the flow tube 1 is further improved by the thermal insulation cotton 51 and the thermal insulation layer 5, and the arrangement of the thermal insulation layer 5 and the thermal insulation cotton 51 can also protect workers, so that the situation that the workers are scalded by the flow tube 1 is reduced.

The implementation principle of the embodiment is as follows: when a worker installs a heat preservation jacket on the surface of the RD wedge-shaped flowmeter, firstly, the guide plate 41 is wound on the outer peripheral surface of the flow tube 1, the first shell 31 and the second shell 32 are simultaneously buckled on the outer peripheral surface of the flow tube 1, and one surface, far away from the flow tube 1, of the guide plate 41 is clamped into the clamping groove 42; the card strip 21 is clamped into the card slot 38; the snap strips 322 snap into the snap grooves 312. The worker can then thread bolts and nuts through the two first connecting plates 34 and the two second connecting plates 35, respectively. So that the first shell 31 and the second shell 32 are mutually buckled on the outer peripheral surface of the flow pipe 1, and finally, the worker sticks the heat insulation cotton 51 on the outer peripheral surface of the heat insulation shell 3 and fixedly connects the heat insulation layer 5 on the outer side of the heat insulation cotton 51. At this time, the worker can introduce the water vapor into the first heat tracing medium hole 311, the water vapor is uniformly contacted with the outer circumferential surface of the flow tube 1 under the guiding action of the guide plate 41, so that the heat of the flow tube 1 and the fluid in the flow tube 1 is preserved, and the preserved water vapor flows out from the second heat tracing medium hole 321.

The embodiment of this specific implementation mode is the preferred embodiment of the present invention, not limit according to this the utility model discloses a protection scope, so: all equivalent changes made according to the structure, shape and principle of the utility model are covered within the protection scope of the utility model.

Claims

1. The utility model provides a RD wedge flowmeter with heat preservation presss from both sides cover, including flow tube (1), each rigid coupling in the both ends of flow tube (1) has a ring flange (2), flow tube (1) outer peripheral face is along the length direction vertical intercommunication of flow tube (1) has two connecting pipes (11), the one end that flow tube (1) were kept away from in connecting pipe (11) is provided with pressure gauge (13), still be provided with a wedge throttle (14) in flow tube (1), wedge throttle (14) are located between two connecting pipes (11), its characterized in that: the heat insulation shell (3) is sleeved on the outer peripheral surface of the flow tube (1), a heat tracing layer (4) is formed in a gap between the heat insulation shell (3) and the outer peripheral surface of the flow tube (1), the heat insulation shell (3) comprises a first shell (31) and a second shell (32) which are mutually buckled, the end parts, facing one side of the connecting tube (11), of the first shell (31) and the end part, facing one side of the connecting tube (11), of the second shell (32) are fixedly connected with a first connecting plate (34), the end parts, facing away from the connecting tube (11), of the first shell (31) and the end part, facing away from the connecting tube (11), of the second shell (35) are fixedly connected with a second connecting plate (35), and after the first shell (31) and the second shell (32) are mutually buckled, the two first connecting;

two ends of the heat preservation shell (3) are respectively abutted against flange plates (2) at two ends of the flow pipe (1), a first heat tracing medium hole (311) for introducing a heat tracing medium into the heat tracing layer (4) is formed in the first shell (31), a second heat tracing medium hole (321) for accommodating the heat tracing medium to flow out is formed in the corresponding second shell (32), and the first heat tracing medium hole (311) and the second heat tracing medium hole (321) are respectively positioned at two ends of the flow pipe (1) in the length direction; the heat tracing layer (4) is also internally provided with a guide plate (41) for guiding the water vapor to regularly flow in the heat tracing layer (4), and the guide plate (41) is spirally arranged on the peripheral surface of the flow pipe (1) along the length direction of the flow pipe (1).

2. An RD wedge flow meter with a thermal jacket according to claim 1, wherein: the one side rigid coupling of ring flange (2) orientation heat preservation shell (3) has a cross-section to be card strip (21) of L type, and the one end of card strip (21) and the perpendicular to surface rigid coupling of ring flange (2), the one end that ring flange (2) were kept away from in card strip (21) set up apart from flow tube (1), correspond all offer on first casing (31) and second casing (32) with card strip (21) complex draw-in groove (38).

3. An RD wedge flow meter with a thermal jacket according to claim 2, wherein: one end of the clamping strip (21) far away from the flange plate (2) is fixedly connected with an isolating strip (211).

4. An RD wedge flow meter with a thermal jacket according to claim 1, wherein: the end face of the first shell (31) facing the second shell (32) is provided with a buckling groove (312), and a buckling strip (322) which can be clamped into the buckling groove (312) is fixedly connected with the end face corresponding to the second shell (32).

5. The RD wedge flow meter with thermal jacket according to claim 4, wherein: a rubber pad (39) is further arranged between the two first connecting plates (34), and a rubber pad (39) is further arranged between the two corresponding second connecting plates (35).

6. An RD wedge flow meter with a thermal jacket according to claim 1, wherein: the inner peripheral surfaces of the first shell (31) and the second shell (32) are provided with clamping grooves (42) which contain the guide plate (41) and clamp and fix the guide plate (41).

7. An RD wedge flow meter with a thermal jacket according to claim 1, wherein: after the first shell (31) and the second shell (32) are buckled with each other, the first heat tracing medium hole (311) and the second heat tracing medium hole (321) are arranged in a back-to-back manner.

8. An RD wedge flow meter with a thermal jacket according to claim 1, wherein: the heat insulation shell is characterized in that a heat insulation layer (5) is further sleeved on the peripheral surface of the heat insulation shell (3), and heat insulation cotton (51) is filled between the heat insulation layer (5) and the heat insulation shell (3).