Vertical square large air volume chemical washing treatment device

Abstract

The present invention relates to the technical field of industrial waste gas treatment equipment, and discloses a vertical square large air volume chemical washing treatment device, including a washing tower, a water spray device for spraying washing liquid and a filling layer placed at the lower end of the water spray device are arranged in the washing tower, a waste gas inlet for introducing waste gas is arranged at the lower part of the washing tower, and a waste gas outlet connected to the waste gas pipeline is arranged at the upper part, the water spray device includes a plurality of nozzles, a side branch pipeline is branched from the middle part of the waste gas pipeline and leads into the washing tower, and a compressor is arranged on the side branch pipeline so that the compressed gas can act on the washing liquid sprayed from the nozzle. The vertical square large air volume chemical washing treatment device disclosed by the present invention utilizes the kinetic energy of part of the waste gas after washing to compress it, and the compressed gas acts on the droplets, so that the droplets are further dispersed to form finer droplets, thereby improving the purification speed, and has the effect of being able to achieve large air volume washing.

Description

Technical Field

[0001] The invention relates to the technical field of industrial waste gas treatment equipment, in particular to a vertical square large-air-volume chemical washing treatment device. Background Art

[0002] The exhaust gas scrubber uses the principle of gas-liquid contact to remove pollutants from the exhaust gas. The exhaust gas enters from the bottom of the tower and fully contacts with the scrubbing liquid (usually water, chemical solution, etc.) sprayed from the top of the tower. During the contact process, the pollutants in the exhaust gas are absorbed, dissolved or chemically reacted by the scrubbing liquid, thereby achieving the purpose of purifying the exhaust gas.

[0003] The main components of the exhaust gas scrubber include nozzles for spraying scrubbing liquid to disperse it, fillers for increasing the contact area between the liquid and the airflow, fans for driving the airflow, and demisting layers for demisting.

[0004] It is common knowledge that the finer and denser the droplets sprayed from the nozzle, the larger the contact area with the filler, and thus the more complete the contact between the gas and the washing liquid. There is still room for improvement in the existing gas-liquid contact efficiency. In addition, the exhaust gas after washing has a certain kinetic energy after being discharged by the fan, which will cause waste if it is not recovered. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a vertical square large air volume chemical washing treatment device, which proposes to use the kinetic energy of part of the exhaust gas after washing to compress this part of the exhaust gas to form compressed gas, and then the compressed gas acts on the droplets sprayed from the nozzle, so that the gas further breaks up the droplets to form finer droplets, thereby increasing the purification speed, and then achieving the purpose of large air volume washing, and at the same time, it can also recover part of the kinetic energy of the exhaust gas to achieve energy reuse.

[0006] The vertical square chemical washing treatment device with large air volume proposed by the present invention comprises a washing tower, a water spraying device for spraying washing liquid and a filling layer arranged at the lower end of the water spraying device are arranged in the washing tower, a waste gas inlet for introducing waste gas is arranged at the lower part of the washing tower, and a waste gas outlet connected with the waste gas pipeline is arranged at the upper part;

[0007] Unlike the traditional exhaust gas scrubber, the water spray device includes several nozzles. A branch pipe is branched from the middle of the exhaust gas pipeline and leads into the scrubber. A compressor is arranged on the branch pipe so that the compressed gas can act on the scrubbing liquid sprayed from the nozzle.

[0008] The purpose of such arrangement is that the exhaust gas after washing has a certain kinetic energy. After a part of the exhaust gas is introduced into the compressor through the bypass pipe, the kinetic energy is further applied to the part of the exhaust gas, and then the exhaust gas is introduced into the washing liquid sprayed from the nozzle to further break up the washing liquid, which can increase the spray area of ​​the washing liquid and reduce the droplet size of the washing liquid.

[0009] In some examples of the present invention, a filter and a fan are also provided on the bypass pipeline. The filter is used to filter the washed exhaust gas to prevent impurities in the exhaust gas from affecting the operation of the compressor, and the fan is used to introduce the filtered exhaust gas into the compressor.

[0010] In some examples of the present invention, a pressure gauge is also provided on the bypass pipeline, and the pressure gauge is used to detect the pressure of the compressed gas, so as to control the operating efficiency of the compressor and avoid the compressed gas pressure being too high and affecting the exhaust gas extraction operation in the washing tower.

[0011] In some examples of the present invention, a pressure relief valve is also provided on the bypass pipeline. When the pressure is too high, the pressure relief valve releases part of the pressure to ensure the normal operation of the washing tower.

[0012] In some examples of the present invention, the nozzle includes a liquid-separating spiral and a gas-separating spiral extending in the spiral direction of the liquid-separating spiral, the inner spiral surface of the gas-separating spiral corresponds to the outer spiral surface of the liquid-separating spiral and a gap is formed therebetween, and an airway for introducing compressed gas and extending in the spiral direction of the gas-separating spiral is provided on the gas-separating spiral, the side of the airway extends to connect with the inner spiral surface to form a compressed gas outlet on the inner spiral surface, and the compressed gas outlet is also spiral-shaped as the airway extends;

[0013] The purpose of such setting is that the nozzle in the exhaust gas washing tower needs to have greater strength to cope with long-term operation. If a compressed gas channel is opened on the basis of the traditional spiral nozzle, it will inevitably affect the strength of the nozzle. Therefore, in this scheme, on the basis of the traditional spiral nozzle, an air separation spiral is introduced, and an air channel for the introduction of compressed air is opened on the air separation spiral, so that the compressed air can travel along the spiral direction and can be sprayed out through the gap to act on the washing liquid.

[0014] In some examples of the present invention, one end of the bypass pipeline extending into the washing tower is divided into several branches, and the several branches are connected to the air passages of several nozzles one by one; that is, the compressed air is distributed one by one at each nozzle.

[0015] In some examples of the present invention, a number of diverter plates are arranged in the airway, and the number of diverter plates are distributed along the spiral direction of the airway; the function of the diverter plates is to guide the gas in the airway, so that the compressed air changes direction to point to the gap, and then points to the liquid under the guidance of the two spiral side walls at the gap, so that the droplets are dispersed.

[0016] In some examples of the present invention, the liquid-separating spiral and the gas-separating spiral are connected by screws, and the two are sealed by a sealing member.

[0017] In some examples of the present invention, the nozzle further comprises an inner cylinder connected to the open end of the liquid-separating spiral and an outer cylinder connected to the open end of the gas-separating spiral, the inner cylinder penetrates the outer cylinder, a compressed air inlet is provided on the outer cylinder, and the branch and the airway are connected through the compressed air inlet;

[0018] The advantage of such a setting is that the entire nozzle still uses the appearance of the traditional structure, and the structure is compact. It only needs to process the existing nozzle and then additionally set up a gas distribution spiral and an outer cylinder to achieve the operation.

[0019] In some examples of the present invention, the outer cylinder is a nut-shaped structure, and one end of the inner cylinder extending out of the outer cylinder is provided with a thread;

[0020] The advantage of such a configuration is that the outer cylinder is used to replace the nut on the traditional nozzle, and the thread uses the connecting thread in the traditional structure, so that other structures in the water spray device can be connected to the nozzle without changing.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a schematic diagram of a vertical square chemical washing treatment device with a large air volume in an embodiment of the present invention;

[0024] Figure 2 is a front view of a nozzle in an embodiment of the present invention;

[0025] Figure 3 is a cross-sectional view of the nozzle at AA in an embodiment of the present invention;

[0026] Figure 4 It is a schematic diagram of the inner spiral surface of the gas-splitting spiral body at a certain section in an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the cross section of the shape of the droplet group sprayed by the traditional spiral nozzle;

[0028] Figure 6 A schematic diagram of a cross-sectional view of the shape of a group of liquid droplets ejected from a nozzle in an embodiment of the present invention;

[0029] Figure 7 A top view of a nozzle in an embodiment of the present invention;

[0030] Figure 8 A partial cross-sectional view of the nozzle at position BB in an embodiment of the present invention;

[0031] Fig. 9 Partial cross-sectional view of the nozzle at CC in an embodiment of the present invention.

[0032] Description of reference numerals:

[0033] Scrubber 100, filling layer 110, waste gas inlet 120, waste gas outlet 130, liquid storage layer 140, air chamber 150, demisting layer 160;

[0034] Water spray device 200, nozzle 210, liquid separation spiral 211, outer rotating surface 211-1, gas separation spiral 212, inner rotating surface 212-1, connecting section 212-1a, inclined section 212-1b, air passage 212-2, compressed gas outlet 212-3, splitter plate 212-4, gap 213, screw 214, seal 215, plug 216, inner cylinder 217, thread 217-1, outer cylinder 218, compressed air inlet 218-1, flat head screw 219, water pump 220, pipeline 230;

[0035] Dosing device 300, automatic dosing machine 310, drug storage cartridge 320, liquid level sensor 330;

[0036] Exhaust pipe 400;

[0037] Exhaust fan 500;

[0038] Auxiliary water spraying device 600, bypass pipeline 610, air compressor 620, filter 630, fan 640, pressure gauge 650, pressure relief valve 660. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0043] Reference below Figures 1 to 9 The vertical square-shaped chemical washing treatment device with large air volume depicts an embodiment of the present invention.

[0044] Please see attached Figure 1 , is a schematic diagram of a vertical square chemical washing treatment device with a large air volume, the chemical washing treatment device comprises a washing tower 100, the washing tower 100 is arranged in a vertical position, a water spraying device 200 for spraying washing liquid and a filling layer 110 arranged at the lower end of the water spraying device 200 are arranged in the washing tower 100, a waste gas inlet 120 for introducing waste gas is arranged at the lower part of the washing tower 100, and a waste gas outlet 130 connected to the waste gas pipeline 400 is arranged at the upper part;

[0045] For details, please refer to the attached Figure 1The washing tower 100 is a vertical structure, having a liquid storage layer 140, an air chamber 150, two stacked filling layers 110 and a demisting layer 160, etc.; wherein the water spraying device 200 can pump the liquid in the liquid storage layer 140 to the nozzle 210, and the liquid is sprayed out by the nozzle 210; an exhaust gas inlet 120 is arranged at the air chamber 150, and the exhaust gas enters the washing tower 100 from here; the filling layer 110 is filled with a fence-shaped structure with a large specific surface area, and the spraying direction of the nozzle 210 points to the filling layer 110, and the demisting layer 160 is equipped with a demisting device to remove water vapor in the exhaust gas.

[0046] Please continue to see the attached Figure 1 In addition to the nozzle 210 , the water spraying device 200 also includes a pipeline 230 and a water pump 220 . The water pump 220 is used to extract the liquid from the liquid storage layer 140 and transmit the liquid to the nozzle 210 through the pipeline 230 .

[0047] Please continue to see the attached Figure 1 The chemical washing treatment device also includes a dosing device 300, which is used to add liquid medicine into the liquid in the liquid storage layer 140 to form a washing liquid. The dosing device 300 includes an automatic dosing machine 310, etc. The input end of the automatic dosing machine 310 is connected to the medicine storage cylinder 320, and the output end is connected to the liquid storage layer 140. The dosing device 300 also includes a liquid level sensor 330. The liquid level sensor 330 is placed in the liquid storage layer 140 and is electrically connected to the automatic dosing machine 310 to obtain the liquid depth and then determine the amount of dosing.

[0048] Please continue to see the attached Figure 1 The exhaust gas pipeline 400 is connected to an exhaust fan 500, and the exhaust fan 500 draws air to form a negative pressure in the washing tower 100, so that the exhaust gas can run from bottom to top, so as to fully contact with the washing liquid sprayed in the filling layer 110, and discharge the washed exhaust gas.

[0049] Please continue to see the attached Figure 1 The water spray device 200 includes a plurality of nozzles 210, and the chemical washing treatment device further includes an auxiliary water spray device 600. The auxiliary water spray device 600 includes a bypass pipe 610 branched from the middle of the exhaust pipe 400, and the bypass pipe 610 leads into the washing tower 100. An air compressor 620 is provided on the bypass pipe 610 so that the compressed gas can act on the washing liquid sprayed from the nozzle 210;

[0050] That is, the exhaust gas in the exhaust gas pipeline 400 is divided into two paths, one path is discharged, and the other path enters the washing tower 100 after compression to act on the washing liquid, so that the droplets formed by the washing liquid have a smaller diameter and a larger area. At the same time, part of the kinetic energy of the exhaust gas can be utilized, which is equivalent to recovering part of the energy and making the washing efficiency of the washing tower 100 higher, thereby achieving the effect of large air volume.

[0051] Please continue to see the attached Figure 1 A filter 630 and a fan 640 are also provided on the bypass pipeline 610. The fan 640 is located between the filter 630 and the compressor 620. The filter 630 is used to filter the washed exhaust gas to prevent impurities from clogging the compressor 620. The fan 640 is used to introduce the filtered exhaust gas into the compressor 620.

[0052] Please continue to see the attached Figure 1 A pressure gauge 650 is also provided on the bypass pipeline 610. The pressure gauge 650 is used to detect the pressure of the compressed gas. The pressure gauge 650 is specifically arranged at a section of the compressor 620 away from the fan 640. It can detect the gas pressure to prevent excessive pressure from hindering the normal discharge of exhaust gas in the washing tower 100.

[0053] Please continue to see the attached Figure 1 The bypass pipe 610 is also provided with a pressure relief valve 660. When the pressure is too high, please continue to refer to the attached Figure 1 , release part of the pressure, thereby achieving pressure stability.

[0054] Please see attached Figure 2 , is a front view of the nozzle 210, the nozzle 210 includes a liquid-separating spiral 211 and a gas-separating spiral 212 extending in the spiral direction of the liquid-separating spiral 211, the inner spiral surface 212-1 of the gas-separating spiral 212 corresponds to the outer spiral surface 211-1 of the liquid-separating spiral 211, and a gap 213 is formed therebetween, and the gap 213 extends to connect with the upper end surfaces of the gas-separating spiral 212 and the liquid-separating spiral 211;

[0055] Please see attached Figure 3 , is a cross-sectional view of the nozzle 210 at AA, an air passage 212-2 for introducing compressed gas and extending along the spiral direction of the air passage 212 is provided on the air separation spiral 212 (the spiral structure of the air passage 212-2 is not shown in the figure), one end of the bypass pipeline 610 extending into the washing tower 100 is divided into a plurality of branches, and the plurality of branches are connected to the air passages 212-2 of the plurality of nozzles 210 one by one (the connection method is not shown in the figure), and the side portion of the air passage 212-2 extends to connect with the inner rotating surface 212-1 to form a compressed gas outlet 212-3 on the inner rotating surface 212-1;

[0056] Please see attached Figure 4 , is a schematic diagram of the inner spiral surface 212-1 of the gas-dividing spiral body 212 at a certain section, and the compressed gas outlet 212-3 is also spirally extended along with the gas passage 212-2.

[0057] Please continue to see the attached Figure 3The inner rotating surface 212-1 includes a connecting section 212-1a that is in contact with the outer rotating surface 211-1 and an inclined section 212-1b that forms a gap 213 with the outer rotating surface 211-1. The gap 213 is the gap 213 mentioned in the previous paragraph. The gap 213 is used for ejecting compressed air, and the compressed gas outlet 212-3 is also arranged on the inclined section 212-1b.

[0058] Please continue to see the attached Figure 3 A plurality of diverter plates 212 - 4 are disposed in the air passage 212 - 2 , and the plurality of diverter plates 212 - 4 are distributed along the spiral direction of the air passage 212 - 2 .

[0059] Compare this nozzle 210 to a conventional spiral nozzle:

[0060] Please see attached Figure 5 , is a cross-sectional view of the shape of a group of droplets ejected from a conventional spiral nozzle. The shape of the group of droplets is a spiral structure, and its cross-sectional shape is shown by g;

[0061] As for the operation of the nozzle 210, please continue to refer to the attached Figure 3 The compressed gas travels along the spiral direction a in the air channel 212-2, and is guided by the diverter plate 212-4 on the way to travel along the direction b, until it enters the gap 213, and is guided by the side wall (the inclined section 212-1b and the corresponding outer spiral surface 211-1) at the gap 213, and is basically ejected along the direction c, and meets the droplets from the direction d. The droplets are further dispersed by the gas and scattered within the range of M;

[0062] Thus forming an attachment Figure 6 The cross-sectional shape of the droplet group in is shown by G. By comparison, it is obvious that the area of ​​G is larger than that of G.

[0063] Please continue to see the attached Figure 3 , and also shows the connection mode between the liquid-separating spiral 211 and the gas-separating spiral 212, which are connected by a plurality of screws 214, and the screws 214 are distributed on each layer of the spiral, so that the liquid-separating spiral 211 and the gas-separating spiral 212 have a stable connection, and the liquid-separating spiral 211 and the gas-separating spiral 212 are sealed by a seal 215;

[0064] Specifically, the screw 214 passes through the connecting section 212-1a and the external rotating surface 211-1 corresponding to the connecting section 212-1a, and a seal 215 is arranged between the connecting section 212-1a and the external rotating surface 211-1. There are two seals 215, which are distributed in a spiral manner between the connecting section 212-1a and the external rotating surface 211-1, and the screw 214 is placed between the two.

[0065] Please continue to see the attached Figure 3A plug 216 is also provided at the head of the screw 214 to seal the screw 214 .

[0066] Please see attached Figure 7-8 , which is a top view of the nozzle 210 and a partial cross-sectional view at BB. The nozzle 210 also includes an inner cylinder 217 connected to the open end of the liquid-separating spiral 211 and an outer cylinder 218 connected to the open end of the gas-separating spiral 212. The inner cylinder 217 penetrates the outer cylinder 218. A compressed air inlet 218-1 is provided on the outer cylinder 218. The branch is connected to the airway 212-2 through the compressed air inlet 218-1.

[0067] Please see attached Fig. 9 , which is a partial cross-sectional view at CC, the inner cylinder 217 and the outer cylinder 218 are also connected by a flat head screw 219.

[0068] Please continue to see the attached Figure 1 The outer cylinder 218 is a nut-like structure, and the nozzle 210 can be operated by using a wrench to act on the nut-like structure. One end of the inner cylinder 217 extending from the outer cylinder 218 is provided with a thread 217 - 1, and the thread 217 - 1 is used to connect with the pipe 230.

[0069] Other components of the chemical washing treatment device according to the embodiment of the present invention, such as: the filling layer 110, the demisting layer 160, the automatic dosing machine 310, the liquid level sensor 330, the exhaust fan 500, the air compressor 620, the filter 630, the fan 640, the pressure gauge 650, the pressure relief valve 660, etc. and their operations are well known to ordinary technicians in the field and will not be described in detail here.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0071] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A vertical square chemical washing treatment device with a large air volume, comprising a washing tower, wherein a water spraying device for spraying washing liquid and a filling layer arranged at the lower end of the water spraying device are arranged in the washing tower, a waste gas inlet for introducing waste gas is arranged at the lower part of the washing tower, and a waste gas outlet connected to the waste gas pipeline is arranged at the upper part; Features: The water spray device includes a plurality of nozzles, a side branch pipe is formed in the middle of the exhaust pipe and leads into the washing tower, a compressor is arranged on the side branch pipe so that the compressed gas can act on the washing liquid sprayed from the nozzle; The nozzle includes a liquid-separating spiral and a gas-separating spiral extending in the spiral direction of the liquid-separating spiral, the inner spiral surface of the gas-separating spiral corresponds to the outer spiral surface of the liquid-separating spiral and a gap is formed therebetween, and the gas-separating spiral is provided with an airway for introducing compressed gas and extending along the spiral direction of the gas-separating spiral, the side of the airway extends to connect with the inner spiral surface to form a compressed gas outlet on the inner spiral surface, and the compressed gas outlet is also spiral-shaped as the airway extends.

2. The vertical square large air volume chemical washing treatment device according to claim 1 is characterized in that: The bypass pipeline is also provided with a filter and a fan, wherein the filter is used to filter the washed exhaust gas, and the fan is used to introduce the filtered exhaust gas into the compressor.

3. The vertical square large air volume chemical washing treatment device according to claim 1 is characterized in that: The bypass pipeline is also provided with a pressure gauge, which is used to detect the pressure of the compressed gas.

4. The vertical square large air volume chemical washing treatment device according to claim 1 is characterized in that: The bypass pipeline is also provided with a pressure relief valve.

5. The vertical square chemical cleaning treatment device with large air volume according to any one of claims 1 to 4, characterized in that: One end of the side branch pipeline extending into the washing tower is divided into a plurality of branches, and the plurality of branches are connected to the air passages of the plurality of nozzles in a one-to-one correspondence.

6. The vertical square chemical cleaning treatment device with large air volume according to any one of claims 1 to 4, characterized in that: A plurality of flow dividers are arranged in the air channel, and the plurality of flow dividers are distributed along the spiral direction of the air channel.

7. The vertical square chemical cleaning treatment device with large air volume according to any one of claims 1 to 4, characterized in that: The liquid-separating spiral body and the gas-separating spiral body are connected by screws, and the two are sealed by a sealing member.

8. The vertical square large air volume chemical washing treatment device according to claim 5 is characterized in that: The nozzle also includes an inner cylinder connected to the open end of the liquid-separating spiral and an outer cylinder connected to the open end of the gas-separating spiral. The inner cylinder passes through the outer cylinder. A compressed air inlet is provided on the outer cylinder. The branch is connected to the airway through the compressed air inlet.

9. The vertical square large air volume chemical washing treatment device according to claim 8, characterized in that: The outer cylinder is a nut-shaped structure, and one end of the inner cylinder extending out of the outer cylinder is provided with a thread.

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