CN212915103U

CN212915103U - VOCs (volatile organic compounds) and odor treatment equipment for industrial sewage gathering and transportation system

Info

Publication number: CN212915103U
Application number: CN202021267314.5U
Authority: CN
Inventors: 宫正; 周畅; 李玉善; 李立远; 陈勇
Original assignee: Dalian Andmir Equipment Co ltd
Current assignee: Dalian Andmir Equipment Co ltd
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2021-04-09
Anticipated expiration: 2030-07-02

Abstract

The utility model discloses VOCs and odor treatment equipment for an industrial sewage gathering and transportation system, which comprises a first air purifying device, a second air purifying device, an induced draft fan, an exhaust chimney and a sealing well cover, and is characterized in that a plurality of first air purifying devices are dispersedly and independently and hermetically arranged at one or more well mouths of each sewage gathering and transportation pipeline in the sewage gathering and transportation system; a gas collection well cover is arranged at the collection position of two or more sewage collection and transportation pipelines in the sewage collection and transportation system or on each sewage collection and transportation pipeline, and the gas collection well cover is sequentially communicated with a group of independent induced draft fans, second air purification devices and exhaust chimneys through pipelines; the sewage gathering and transporting system is provided with a sealing well cover used for sealing the sewage gathering and transporting system at a wellhead and/or an open position which is not provided with the first wind purifying device.

Description

VOCs (volatile organic compounds) and odor treatment equipment for industrial sewage gathering and transportation system

Technical Field

The utility model relates to a petrochemical field, specifically speaking relates to a be used for defeated system of sewage collection among the petrochemical industry, carry out the treatment facility of effective improvement to the foul smell of each inspection shaft, bilge well and/or other uncovered position outputs.

Background

Volatile Organic Compounds (VOCs) and hydrogen sulfide (H)₂S), organic sulfide, odorous gas, benzene, toluene, xylene and the like are main pollutants in the odor discharged by the petrochemical industry, and with the stricter requirements on ecological environment, the establishment of a standardized odor control task by petrochemical enterprises is urgent. In which VOCs and H are used₂S is typical malodorous gas, which not only causes great potential safety hazard to enterprise production, but also causes serious corrosion to equipment and pipelines and increases production cost. Meanwhile, the life health of the staff is greatly harmed, and the ecological environment is seriously influenced. And the harmful gases generated in the production process are organized and treated, so that qualified emission is realized. However, in the sewage collecting and transporting system, odor is still generated and is discharged from each inspection well, sewage well or other open positions, which belongs to inorganization odor discharge and is not properly disposed, and because the sewage collecting and transporting system has long pipelines and a large number of inspection wells, sewage wells or other open positions, namely, the sewage collecting and transporting system has the characteristics of wide dispersion area, low relative pollutant concentration, high collection and detection difficulty and the like, the odor discharged from the sewage collecting and transporting system is difficult to carry out organized and standardized treatment technology and means.

In particular, because the sewage gathering and transportation system has a large transportation range and complicated trend of each sewage pipeline, the sewage is difficult to be effectively collected and treated uniformly and is discharged organized, in order to solve the problem, the existing method is to directly seal all well covers in the sewage gathering and transportation system, although the unorganized discharge of odor is reduced to a certain degree, most toxic and harmful gases are continuously accumulated and enriched in the sewage well and the pipeline, and the potential risks of pipeline corrosion and sewage well explosion are aggravated.

SUMMERY OF THE UTILITY MODEL

Aiming at the unorganized discharge of VOCs and H in pollution sources such as sewage pipelines, sewage wells, oil separating wells and the like in a sewage gathering and transportation system₂The utility model provides a VOCs and odor treatment equipment that is used for defeated system of industrial sewage collection that distributed, treatment effeciency are higher, the overall arrangement is more nimble, technical feasibility is higher for odor treatment' S such as S technical difficulty and current processing method not enough.

The utility model discloses a VOCs and odor treatment equipment for industrial sewage gathering and transportation system, which comprises a first air purifying device, a second air purifying device, a draught fan, an exhaust chimney and a sealing well cover, wherein a plurality of first air purifying devices are separately and independently arranged at one or more well openings of each sewage gathering and transportation pipeline in the sewage gathering and transportation system in a sealing way; a gas collection well cover is arranged at the collection position of two or more sewage collection and transportation pipelines in the sewage collection and transportation system or on each sewage collection and transportation pipeline, and the gas collection well cover is sequentially communicated with a group of independent induced draft fans, second air purification devices and exhaust chimneys through pipelines; the sewage gathering and transporting system is provided with a sealing well cover used for sealing the sewage gathering and transporting system at a wellhead and/or an open position which is not provided with the first wind purifying device.

Preferably, a wellhead for installing the first wind purifying device is manufactured on a wellhead concrete foundation, and a positioning embedded part for sealing and fixing the first wind purifying device is buried in the wellhead concrete foundation.

Preferably, first air purification device is including the box, the box is formed with base part and main part respectively inside from up being provided with preprocessing unit, membrane processing unit, absorption processing unit according to the preface down, the top of box is sealed, is fixed with a row of wind lid.

Preferably, a plurality of rings locating lever are installed to the base portion of box, the rings locating lever is the internal thread siphunculus, and upper portion and the direct threaded connection of eyebolt, bottom and the peripheral location built-in fitting in well head position and first sealed pad are connected.

Preferably, the membrane processing unit is fixedly installed in the main body part above the pretreatment unit, and comprises a support frame fixedly connected with the inner wall of the box body and a selective unpowered gas membrane device hermetically connected with the support frame through a sealing ring.

Preferably, the unpowered gaseous membrane device of selectivity with the shape phase-match of box is including being located arch all around, being concave pelvic floor structure in the middle of being located, is provided with an annular groove in the middle of arch all around, the pelvic floor structure is provided with a logical groove in middle lowest position to be provided with automatic drainage choke device in the middle of leading to the groove, the pelvic floor structure is followed lead to the groove and form the inclined plane toward the side, it has the unpowered gaseous membrane of selectivity to paste on the inclined plane.

Preferably, the adsorption treatment unit comprises a packing rack detachably connected with the top in the box body, the bottom of the packing rack is provided with a rack slotting tool which can be hermetically connected with the membrane treatment unit, a plurality of packing boxes which are parallel up and down and can be filled and replaced with different materials respectively are arranged in the packing rack, and a second sealing gasket is arranged at the joint of each packing box and the packing rack.

The utility model discloses in be arranged in VOCs and odor treatment equipment of defeated system of industry sewage collection for every sewage collection defeated pipeline solves VOCs and H in the unorganized emission foul smell among the defeated system of current sewage collection with a brand-new distributed processing mode₂S and other odor pollutants, and realizes VOCs and H in the sewage gathering and transportation system well and in the drainage pipeline₂S and other odors are collected, conveyed, purified and discharged organically.

Through the second air purifying device integrating power and multi-technology coupling, a pretreatment technology, a desulfurization technology, a photocatalytic oxidation technology, a biological deodorization technology and an adsorption technology are arranged in the second air purifying device, odor generated by the industrial sewage gathering and transportation system is collected in a centralized manner and discharged after treatment.

Based on the use of the first air purifying device and the second air purifying device, the modular design and standardized production can be realized, and the device has the characteristics of low investment operation cost, high treatment efficiency and technical feasibility, flexible layout, simple and convenient installation and maintenance and the like.

Drawings

Fig. 1 is a schematic structural view of the odor treatment device of the present invention.

Fig. 2 is a schematic front view of the first wind purifying device of the present invention.

Fig. 3 is a schematic view of the internal structure of the first wind purifying device of the present invention.

Fig. 4 is a schematic perspective view of the middle box body of the present invention.

Fig. 5 is a schematic perspective view of the selective unpowered gas membrane device of the present invention.

Fig. 6 is a schematic side view of a selective unpowered gas membrane unit of the present invention.

Fig. 7 is an enlarged schematic view of a portion a in fig. 3.

The reference numbers in the figures illustrate: 1 a first air purifying device, 2 a second air purifying device, 3 a wellhead concrete foundation, 4 an air collecting well cover, 5 an induced draft fan, 6 a sealing well cover, 7 a sewage gathering and transportation pipeline, 8 an exhaust chimney, 9 a pipeline, 10 a base part, 11 a main body part, 12 a flame-retardant heat-insulating layer, 13 a lifting ring positioning rod, 14 a lifting ring bolt, 15 a positioning embedded part, 16 a first sealing gasket, 17 a pretreatment unit, 18 a membrane treatment unit, 19 an adsorption treatment unit and 20, the device comprises a ventilation cover, a 30 supporting frame, a 31 sealing ring, a 32 selective unpowered gas membrane device, a 33 annular groove, a 34 bulge, a 35 basin bottom structure, a 36 automatic drainage and air blocking device, a 37 through groove, a 38 selective unpowered gas membrane, 39 liquid jelly glue, a 40 filler hanger, a 41 filler box, a 42 hanger slotting tool, a 43 second sealing gasket, a 50 ventilating window, a 51 lock catch, a 52 fire blocking net, a 53 fire retardant type heat preservation layer and a 54 third sealing gasket.

Detailed Description

Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings, wherein the illustrated embodiments are illustrative of the present invention and not restrictive. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As shown in fig. 1, the utility model discloses a VOCs and odor treatment equipment for industrial sewage gathering and transportation system includes a plurality of unpowered purification treatment's first air purification device 1, multiunit are by the power purification device that second air purification device 2, draught fan 5, exhaust stack 8 are constituteed to and be used for sealing the whole sewage gathering and transportation system's sealed well lid. Firstly, planning and distinguishing each sewage gathering and transporting pipeline in a sewage gathering and transporting system according to the trend of the sewage gathering and transporting pipeline, and independently treating each planned and distinguished sewage gathering and transporting pipeline (also called a drainage pipeline) 7; a plurality of first wind purifying devices 1 are dispersedly and independently and hermetically arranged at one or more wellheads of sewage gathering and transporting pipelines in a sewage gathering and transporting system; a gas collection well cover 4 is arranged at the collection position of two or more than two sewage collection and transportation pipelines in the sewage collection and transportation system, and the gas collection well cover 4 is sequentially communicated with a group of power purification devices through a pipeline 9. The method comprises the following specific operations:

1) planning and distinguishing each sewage gathering and transportation pipeline in the sewage gathering and transportation system according to the trend of the sewage gathering and transportation pipeline, and independently treating each planned and distinguished sewage gathering and transportation pipeline (also called a drainage pipeline) 7; specifically, a first wind purifying device 1 is hermetically arranged at one or more wellheads of each sewage gathering and transportation pipeline 7; for example, the sewage gathering and transportation system distributed in a shape like a Chinese character 'tian' is distinguished according to the trend of each sewage gathering and transportation pipeline 7, and the sewage gathering and transportation pipelines 7 with 12 line segments and the collection positions of 9 sewage gathering and transportation pipelines 7 are arranged, a plurality of water seal well heads, inspection well heads, oil separation well heads, water collection well heads and the like are distributed on the sewage gathering and transportation pipeline 7 of each line segment, preferably, the utility model discloses install a first air purifying device 1 on the well heads at the starting end and the tail end of the sewage gathering and transportation pipeline 7 of each line segment, certainly can install a plurality of first air purifying devices 1 on a plurality of well heads of the sewage gathering and transportation pipeline 7 of each line segment (strip), and the specific well heads can be different from the water seal well heads, the inspection well heads, the oil separation well heads and the water collection well heads; before the installation of first air purification device 1, need make well head concrete foundation 3 at the installation well head, make firm, level and smooth ground, guarantee first air purification device 1 installation and the stability and the leakproofness of operation.

2) A gas collection well cover 4 is added at the collection position of the sewage collection and transportation pipeline 7 and is used for collecting odor generated in the sewage collection and transportation system, and the gas collection well cover 4 is sequentially communicated with an induced draft fan 5, a second air purification device 2 and an exhaust chimney 8 through a pipeline 9;

the method comprises the following steps: still take the sewage gathering and transportation system distributed in a shape like a Chinese character 'tian' as an example, a gas collection well cover 4 is arranged at four corners and at the position where the middle is criss-cross, a group of draught fans 5, second air purifying devices 2 and exhaust chimneys 8 are arranged aiming at one gas collection well cover 4, the draught fans 5 are used for pumping out odor in the sewage gathering and transportation system through pipelines 9 and the gas collection well cover 4, the odor enters the second air purifying devices 2 for collection, transportation and purification treatment, and finally the odor is organized and discharged through the exhaust chimneys 8. The second air purifying device 2 is a power type multi-technology coupling combined waste gas purifying device, and the related coupling combined technology mainly comprises a pretreatment technology, a desulfurization technology, a photocatalytic oxidation technology, a biological deodorization technology and an adsorption technology, and is used for intensively collecting odor generated by the industrial sewage gathering and transportation system and discharging the odor after treatment. The second wind purifying device 2 may be a wind purifying device in the prior art of tissue processing, and will not be described in detail herein.

Certainly, the second air purifying device 2 can also be installed at the interlude of every sewage gathering and transportation pipeline 7, sets up the gas collection well lid 4 at the interlude of sewage gathering and transportation pipeline 7 promptly, is applicable to the sewage gathering and transportation pipeline 7 of longer distance, takes out VOCs and the foul smell in the sewage gathering and transportation pipeline 7, carries out effective processing.

3) Sealing treatment is carried out on the well mouth and/or the open position of the sewage gathering and transportation system which is not provided with the first air purifying device 1 by using a sealing well cover 6;

the method comprises the following steps: the well mouth of each line segment (strip) sewage gathering and transportation system 7 which is not provided with the first air purifying device 1 is sealed by the sealing well cover 6, namely the sealing well cover 6 is used for replacing the original well cover in the sewage gathering and transportation system, so that the sealing performance of the whole sewage gathering and transportation system is ensured, and the gas in the whole sewage gathering and transportation system can only be discharged after being treated by the first air purifying device 1 and/or the second air purifying device 2;

the operation is carried out in the following way:

under the normal state, the first air purifying device 1 carries out desulfurization, oxidation and adsorption treatment on the odor in the sewage gathering and transportation system, and directly discharges the gas which reaches the standard and is discharged; in particular to a method for realizing the unpowered operation by utilizing the membrane processing unit 18 in the first air purifying device 1 to purify the unorganized exhaust gas. In detail, the toxic and harmful gas volatilized in the sewage gathering and transportation system firstly enters the pretreatment unit 17 of the first air purifying device 1 to remove water mist and oil gas, then the enrichment and screening of pollutants are realized through the membrane treatment unit 18, and H in the pollutants₂The S is decomposed and removed after passing through a desulfurization unit in the adsorption treatment unit, most of VOCs and other odor are polymerized and decomposed after passing through a catalytic oxidation unit, and the remaining few VOCs and other odor are finally and thoroughly adsorbed and purified in the adsorption unit.

When the gas pressure in the sewage gathering and transportation system reaches a preset value, the second air purifying device 2 is started, the odor in the sewage gathering and transportation system is extracted through the draught fan 5, the second air purifying device 2 is used for desulfurization, oxidation and adsorption treatment, and finally the gas which reaches the standard and is discharged through the exhaust chimney 8. All pollutant indexes of the gas purified by the first air purifying device 1 and the second air purifying device 2 meet the emission standards regulated by the relevant national standards, and the potential safety hazard and the environmental protection risk caused by the unorganized emission of odor of a sewage gathering and transportation system in an enterprise factory are thoroughly solved.

Of course, the second air purifying device 2, the draught fan 5 and the exhaust chimney 8 can also adjust the start-stop time according to the length of the sewage gathering and transportation system and the working condition, so that the regular start is realized.

When the second air purifying device 2, the draught fan 5 and the exhaust chimney 8 work, the first air purifying device 1 reversely admits air, and air is input into the industrial sewage gathering and transportation system through the first air purifying device 1 to supplement the gas pressure of the industrial sewage gathering and transportation system.

As shown in fig. 2 and 3, the first air purifying device 1 includes a box body, the bottom of the box body is open and can be hermetically connected with the inspection well, the sewage well and/or the open position, the top of the box body is hermetically and fixedly connected with an exhaust cover 20, so that all odor discharged from the inspection well, the sewage well and/or the open position enters the box body, demisting, dewatering, desulfurizing, oxidizing and adsorbing treatment is performed inside the box body, and the odor is discharged into the air from the exhaust cover 20 after reaching the discharge standard.

The box body is integrally formed by metal materials, and of course, the box body can also be integrally formed by injection molding of other plastics with fireproof functions. The utility model provides a box is a closed box that only has upper and lower open, forms base portion 10 and main part 11, and longitudinal section is the T font of invering, and transverse section can be square, also can be other shapes such as circular, as shown in fig. 4, and this embodiment uses square as the example to explain. The inside from bottom to top of box is fixed mounting in proper order has preprocessing unit 17, membrane processing unit 18, collects desulfurization, oxidation, absorption function adsorption treatment unit 19 as an organic whole. The method comprises the following steps:

as shown in fig. 3, a flame-retardant insulation layer 12 is fixedly attached to an inner wall surface of the main body portion 11 of the box body in a sticking manner. And hanging ring positioning rods 13 which penetrate through the base part 10 are respectively arranged at four corners of the base part 10. The lifting ring positioning rod 13 is an internal thread through pipe, the upper part of the lifting ring positioning rod is directly in threaded connection with the lifting ring bolt 14, and the mounting and the dismounting are convenient; the bottom is connected to a positioning embedment 15 embedded in the wellhead concrete foundation 3 and sealed by a first seal gasket 16 before the base portion 10 is connected to the positioning embedment 15, preventing odor discharged from the inspection well, the sewage well and/or the open place from being discharged from a gap between the box body and the ground.

The base portion 10 is internally and fixedly provided with a pre-processing unit 17, the shape of the pre-processing unit 17 is the same as that of the box body, and the pre-processing unit 17 is a square demisting device which is fixedly positioned and fixed on the inner top of the base portion 10 through a set screw (not shown in the figure), so that all the gas entering the box body of the processing body can rise into the main body portion 11 after passing through the demisting device. The defogging device is a mature product sold in the market, and the specific structure and the working principle of the defogging device are not described in detail.

The membrane treatment unit 18 is fixedly mounted inside the main body 11 above the pretreatment unit 17, and as shown in fig. 3, the membrane treatment unit 18 includes a support frame 30 fixed to the inner wall surface of the tank by welding or the like, and a selective non-powered gas membrane unit 32 sealingly connected to the support frame 30 by a sealing ring 31, a bolt or the like. In detail, the selective unpowered gas membrane device 32 is matched with the shape of the box body, is square, and as shown in fig. 5, comprises a protrusion 34 positioned on the periphery and a basin bottom structure 35 positioned in the middle and concave, an annular groove 33 is arranged in the middle of the protrusion 34, a through groove 37 is arranged at the lowest position in the middle of the basin bottom structure 35, and an automatic water and gas discharging and blocking device 36 is arranged in the middle of the through groove 37, wherein the automatic water and gas discharging and blocking device 36 is made of ABS + PC plastic, and can discharge redundant liquid in the through groove 37. The basin bottom structure 35 forms an inclined plane from the through groove 37 to two sides, a selective unpowered gas membrane 38 is adhered on the inclined plane of each side, gas entering through the demisting device can enter the upper part of the membrane processing unit 18 through the selective unpowered gas membrane 38, and water is stopped below the membrane processing unit 18 by the selective unpowered gas membrane 38. A small amount of water entering the membrane treatment unit 18 above the selective non-energized gas membrane 38 is collected by the channel 37 and discharged from the automatic water discharge air lock 36. The selective unpowered gas membrane 38 is a commercially available mature product and will not be described in detail.

The interior top installation of box adsorbs processing unit 19, adsorbs processing unit 19 including the filler stores pylon 40 of fixed mounting top in the box, and filler stores pylon 40 is a square frame that matches with box shape side, seals all around, the open structure in both ends. The bottom of the packing hanger 40 is provided with a square hanger slotting cutter 42, when the packing hanger 40 is arranged in the box body, the hanger slotting cutter 42 is just inserted into the annular groove 33 arranged on the bulge of the selective unpowered gas membrane device 32, then the liquid jelly 39 is injected into the annular groove 33, after the liquid jelly 39 is solidified, a good sealing effect is formed between the membrane treatment unit 18 and the adsorption treatment unit 19, and simultaneously the bottom of the packing hanger 40 is abutted against the upper surface of the bulge 34 of the selective unpowered gas membrane 38, as shown in fig. 6.

The inside stuffing box 41 that is equipped with three parallel arrangement from top to bottom of filler stores pylon 40, stuffing box 41 inserts the installation through drawer type structure, from up three stuffing box 41 inside filled with decomposition material according to the preface down, catalytic material, adsorbing material, can carry out the desulfurization to the foul smell among the gathering and transportation system, the oxidation, effective processing such as absorption, the junction between every stuffing box 41 and filler stores pylon 40 all is provided with the sealed pad 43 of second, this sealed pad 43 of second is rubber packing, can the effective control foul smell flow direction, and the treatment efficiency is improved. When the replacement of the packing is required, the adsorption treatment unit 19 is taken out together with the membrane treatment unit 18, and the replacement of the packing and the replacement of the selective unpowered gas membrane 38 are performed.

The upper part of the box body is provided with a detachable exhaust cover 20, the exhaust cover 20 is provided with a ventilation window 50, the ventilation window 50 is internally provided with a fire retardant net 52, the fire retardant net 52 is made of brass, the inner wall of the exhaust cover 20 is provided with a fire retardant type heat preservation layer 53, the exhaust cover 20 is connected with the top of the box body in a hidden locking way through two lock catches 51 arranged inside, and the space between the exhaust cover 20 and the box body is sealed by a third sealing gasket 54, as shown in figure 7.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A VOCs and odor treatment device for an industrial sewage gathering and transportation system comprises a first air purifying device, a second air purifying device, an induced draft fan, an exhaust chimney and a sealing well cover, and is characterized in that a plurality of first air purifying devices are dispersedly and independently and hermetically arranged at one or more well mouths of sewage gathering and transportation pipelines in the sewage gathering and transportation system; a gas collection well cover is arranged at the collection position of two or more sewage collection and transportation pipelines in the sewage collection and transportation system or on each sewage collection and transportation pipeline, and the gas collection well cover is sequentially communicated with a group of independent induced draft fans, second air purification devices and exhaust chimneys through pipelines; the sewage gathering and transporting system is provided with a sealing well cover used for sealing the sewage gathering and transporting system at a wellhead and/or an open position which is not provided with the first wind purifying device.

2. The apparatus according to claim 1, wherein the first air purifying device is installed at a wellhead concrete foundation, and a positioning embedded part for sealing and fixing the first air purifying device is embedded in the wellhead concrete foundation.

3. The apparatus according to claim 1, wherein the first air purifier comprises a housing, the housing is formed with a base portion and a body portion, the housing is internally provided with a pretreatment unit, a membrane treatment unit and an adsorption treatment unit in sequence from bottom to top, and a top of the housing is sealed and fixed with an exhaust cover.

4. The apparatus according to claim 3, wherein the base of the housing has a plurality of rings, the rings are internally threaded, the upper part of the rings is directly threaded with bolts, and the bottom of the rings is connected with the first gasket and the positioning embedded part around the wellhead.

5. A VOCs and odor control device for industrial sewage collection and transportation system according to claim 4 wherein said membrane treatment unit is fixedly mounted inside said main body portion above said pretreatment unit, said membrane treatment unit comprising a support frame fixedly attached to an inner wall of said housing, and a selective non-powered gas membrane unit sealingly attached to said support frame by a sealing ring.

6. A VOCs and odor control device for industrial sewage gathering and transportation system according to claim 5 wherein the selective unpowered gas membrane device matches the shape of the tank body and includes a raised peripheral and a recessed middle basin bottom structure, an annular groove is provided in the middle of the raised peripheral, the basin bottom structure is provided with a through groove in the lowest middle position and an automatic drainage and air-lock device in the middle of the through groove, the basin bottom structure forms an inclined plane from the through groove to the side edge, and the selective unpowered gas membrane is adhered on the inclined plane.

7. The apparatus according to claim 3, wherein the adsorption treatment unit comprises a packing rack detachably connected to the top of the box body, the bottom of the packing rack is provided with a rack slotting tool which can be hermetically connected to the membrane treatment unit, the packing rack is internally provided with a plurality of packing boxes which are parallel up and down and can be filled with and replace different materials, and a second sealing gasket is arranged at the joint of each packing box and the packing rack.