The Research Status and Development Prospect of the Cross Air

Blow

Mingyuan Du

,Fengdong Pi

, He Liao

,Jinhong Li

and Xuehui Gan*

Textile Equipment Engineering Research Center of the Ministry of Education, Donghua University, No. 2999North

enmin

Road, Shanghai, China

Keywords: Cross air blow, research status, development prospect, technical route, flexibility.

Abstract: This paper briefly describes the development situation and present status of the cross air blow for the key

components of the spinning equipment at home and abroad. The structural characteristics of the circular

blow device are analyzed, and the development prospect of the cross air blow is discussed and

predicted. Combined with the current situation of development and application of flexible technology in

China’s chemical fiber industry, this paper discusses the application of flexible technology in the cross air

blow and points out the research methods and technological routes of the new flexible cross air blow.

1 PREFACE

Chemical fiber manufacturing is an important part of

basic materials and textile industry in China

whichhas strong international competitiveness. The

world's manufacturing center for chemical fiber

machinery is shifting to China1.

With the continuous growth of China's economy

and the increasing consumption capacity of domestic

residents, the demand of polyester fiber in China is

also increasing. From the polyester fiber production

distribution point of view, the proportion of filament

production increased year by year. China's polyester

fiber production totaled 3917.97million tons in 2015

while filament production was 29.5807 million tons.

Filament production increased by 12.26% and

accounted for more than 75% of the polyester fiber

production

.When melt spinning is used, the melt is

ejected from the spinneret’s capillaries, cooled by

blowing, stretched, and finally solidified into

filaments. Cooling has an important role in melt

spinning forming process. Heat exchange between

polymer melt and air flow directly affects the

velocity distribution,stress distribution and

temperature distribution during spinning process so

that the linear density uniformity,structural

uniformity,stability of surface morphological, the

length of solidifying region of fiber are

affected.With the increase of the high quality

product rate requirements in chemical fiber industry,

lateral blow air quenching device has been unable to

meet the requirements of filament production. The

circular blowair quenching device can effectively

solve the problem of wind energy loss due to the

large area of the lateral blow air quenching device.

In addition, the cross air blow device can also make

each wire wind uniformly, with potential economic

benefits and broad application prospects. At present,

China's polyester fiber single-line production

capacity is getting higher and higher, but product

homogeneity is serious and the differentiated rate of

chemical fiber products is insufficient. Problems like

overproduction of general-purpose products, poor

quality stability, and large fluctuations in

performance make it difficult to meet the increasing

demand for consistent product quality. Therefore,

achieving flexible processing in high-capacity and

continuous equipment and developing small

quantities and more varieties of products are urgent

technologies.

2 RESEARCH STATUS OF CROSS

AIR BLOW DEVICE

2.1 Research Status in China

Since the 1980s, China began to research and

develop cross air blow device. At that time the

research project was to improve the imported

equipment of polyester staple fiber and develop

domestic equipment based on the digestion and

absorption of foreign cross air blow device3.With

the adaptation to international textile technology

development, domestic manufacturers also begin to

research and develop cross air blow device used in

filament production in recent years.

China Shanghai Pacific Textile Complete

Equipment Co.,Ltd.4has developed polyester staple

fiber complete sets of equipment with low damping

outer cross air blow device which is equipped with a

blowing air volume automatic control system.In

order to adapt to the complexity of the raw materials

in the renewable polyester staple fiber complete

equipment, semi-open type outer cross air blow and

single-distribution air volume control device are

configured, which effectively meets the

requirements for the control of the air flow rate and

air temperature of the spinning process.Polyester

staple fiber spinning machine manufactured by

Hunan Shaoyang Textile Machinery Co., Ltd. is

equippedwith low damping inner cross air blow

device. It solves the problems of high investment

and high running cost caused by high wind pressure

of some main air ducts of high-damping imported

cross air blow device.Beijing Chonglee Machinery

Engineering Co., Ltd. has developed a new type of

outer cross air blow device for ultrafine fibers. The

air rectifier tube has the advantages of uniform air

blowing, easy cleaning and replacement. The line

sealing technology is used between blow head box

and spinning boxwhich ensures tight and reliable

sealing. The height of the no-wind zone can be

adjusted according to the requirements of the

production process. At the same time there is

cylinder lift which is supplemented by column-type

linear bearing guide rail. The device has the

characteristics of uniform lifting and stability, and

the positioning pin on the cross air blow device can

make the positioning of the ring blowing head more

precise.

At present, the most widely used technology is

the outer cross air blow technology. However,no

matter inner cooling or outer cooling, the volume

flow of the cross air blow increases geometrically as

the diameter of the spinneret and the cooling air

passing radius increase. The effect on the cooling

uniformity of the inner and outer fiber is also

magnified.Due to the high quality and technical

difficulty of producing differentiated fiber filaments,

such as fine and ultra-fine fibers, the requirements

for uniformity of filament cooling are higher.In

particular, it is required that the circumferential wind

speed be uniform, andthe range of wind speed is

extremely small, and the wind speed is stable and

smooth. The axial wind speed change curve is gentle

while the unevenness of wind speed is less than 4%.

However, the uniformity and stability of the wind

speed of the cross air flow device and the sealing of

the equipment still need to be further improved to

meet the quality requirements of the products.

2.2International Research Status

Internationally, the cross air blow devices for short-

fiber production have been developed and applied as

early as the 1970s. Such as Germany's Gemma,

Neumag, Inventa, and the Du Pont Co. have a lot of

research on the cross air blow device and formed

their own proprietary technologies. With the

growing demand for filament in the textile market,

cross air blow technology is increasingly used in

filament yarn production. In order to solve the high

quality requirements of filament cooling, foreign

manufacturers of cross air blow device are also

ongoing researching and improving. Three typical

technical schools of filament cooling were formed

gradually, namely TMT in Japan, Barmag in

Germany, and Samsung in Korea3.

TMT Machinery Co., Ltd. has developed a CIQ

outer cross air blow device for spinning fine denier

fiber. It can ensure the uniformity of the wind

received by each bundle, but the wind resistance of

the wind direction rectification cylinder is large so

that the energy consumption is relatively large.In

addition, it has excellent processability for porous

ultrafine fibers such as 0.3D monofilaments since

the reduction between rectifier holes. Spinning more

than 288 holes can be performed on spinnerets with

an outer diameter of 85mm.As shown in Fig. 1, the

EcoQuench outer cross air blow device developed

by OerlikonBarmag4not only reduces the amount of

air-conditioning air flow needed for the cooling

process of the strands silk by about 40%, but also

effectively saves energy consumption. The quality of

fine denier yarns is significantly improved, and the

CV value of the product can be reduced to 1.0 or

less.Inventa and Neumag have researched and

developed the inner cross air blow equipment, and

Zimmer has developed the outer cross air blow

technology.Most blowing heads were designed with

high damping in 1970swhose damping rectifier

element was made of microporous sintered material

or microporous non-metallic material while the air

pressure of the air duct is between 6000-8000 Pa.

The advantage of the high damping blower is that

the speed of the blowing cool air is stable and the

wind speed difference between the upper and lower

parts of the blower is small. The disadvantage is that

the energy consumption and the energy cost is high.

Figure 1: Eco Quench outer cross air blow system.

3 INTRODUCTION TO THE

STRUCTURE OF THE CROSS

AIR BLOW DEVICE

Such as the outercross air blowshown in Fig. 2. The

working principle of the device is as follows: After

the cooling air enters the air duct, rectification is

performed through the perforated plate 6 to enter the

lower air chamber, and then the second rectification

is performed through the perforated plate 4 to enter

the upper air chamber. Next, the cooling air is

rectified and homogenized through the outer porous

plate 1 and the inner porous plate 2. The cooling air

is then evenly blown from the wire mesh 3 to cool

the tow and finally to the surrounding air.The

cooling air finally blow out evenly from the wire

mesh 3 to cool the tow and dissipate to the

surrounding air.

The cooling air of the outer cross air blow is

blown circumferentially uniformly from the outside

of the tow to the arranged tow endlessly. The wind is

very close to the tow to make excellent use of

energy. Since the cooling air does not need to cross

the multi-layer fibers, the rise of the cooling air

temperature is small and the cooling conditions of

the tow are similar.

Figure2:Cross air blow structure diagram.

1-outer porous plate 2-inner porous plate 3-wire mesh

4-horizontal porous plate 5- air chamber6-perforated plate.

4 NEW FLEXIBLE CROSS AIR

BLOW DEVICE

Flexible manufacturing system (FMS) is a group of

CNC machine tools and other automated process

equipment, which is composed of computer

information control system and material automatic

storage system. The so-called flexible fiber spinning

technology

refers to adopting or replacing different

functional modules or devices on the same fiber

spinning equipment to produce different varieties

and different functions of differentiated fiber to meet

the production requirements of small batches and

varieties.

4.1Research on Flexible Cross Air Blow

Device

In recent years, due to the continuous growth of

domestic chemical fiber production capacity, the

growth rate of corporate profits has declined.

Against this background, the chemical fiber industry

as a whole is trying hard to adapt itself to the

complicated external environment such as sluggish

demand in the international market, the upgrading of

domestic consumption structure, the fluctuation of

raw material prices, and the high manufacturing

costs. The industry has basically maintained steady

growth by focusing on technological innovation,

smart manufacturing, and green circulation to

improve supply quality. Flexible and multifunctional

differential modification technologies will continue

to be the focus for the development of chemical fiber

companies in the near future. In addition, China's

“13th Five-Year Development Guidance Opinions

for Chemical Fiber Industry”6also listed flexible

technology as a key development area and direction,

and proposed to build an innovative platform for

chemical fiber efficient and flexible manufacturing

technologies to solve the technical bottleneck of

product development .At present, the design

processing and production of China's chemical fiber

equipment are becoming more mature and ever-

growing. The standardization, modularization and

multi-functionalization of spinning equipment are

still the main development directions in the future.

In addition, it is imperative to realize the interchange

of cross air blow and lateral blow, as well as the

development of flexible cross air blow systems that

adapt to small batches and varieties.

The term "flexibility" can be understood from an

engineering perspective as the ability and

characteristics to adapt to change. Specifically: (1)

Adapt to product changes such as product

modification and new product development; (2)

Adapt to changes in production systems such as new

equipment, new production methods, new control

systems, and new production personnel; (3) Adapt to

changes of requirements, such as changes in product

quantity and instability during the production cycle.

The flexibility of the flexible cross air blow device

can be embodied in four aspects, namely product

flexibility, mechanical flexibility, process flexibility,

and control system flexibility.

The main sign of product flexibility is the range

of flexibly adapted products which refers to the

range of differentiated and functionalized fibers that

can be blown and cooled by the flexible cross air

blow device. Mechanical flexibility refers to the

adaptability that machinery exhibits when the

product type changes, such as the requirement to

produce a certain size of fiber. It shows whether the

flexible cross air blow system has the necessary

functional devices, the adjustable range of the

machine output, and the ability to achieve fiber

performance. Process flexibility mainly depends on

the richness and reliability of the process. It is

required to provide the optimum blowing conditions

and the constraint parameters or evaluation functions

for blowing process control on all kinds of fibers

processed. The flexibility of the control system is

controlled by the computer and therefore depends on

the level and ability of the computer system to

operate in real time. The adoption of flexible

systems has greatly increased the degree of influence

of random factors. The computer system must

monitor the actual operating conditions of the

processing system at any time and correct the

process parameters and conditions in a timely

manner so that the production can maintain the best

state. The computer system must monitor the actual

operating state of the processing system at any time,

and correct the process parameters and conditions in

time to keep the production in the best condition. As

shown in Fig. 3, the machine flexibility and process

flexibility complement each other, and the flexibility

of the control system controls the mechanical

flexibility and process flexibility to achieve product

flexibility.

4.2 The Research Line of Flexible

Cross Air Blow Device

4.2.1 Establishing a Database Between

System Functional Structure and

Product Variety

The study of the flexible cross air blow device must

begin with fiber cooling forming theory. Combined

with the knowledge of heat transfer, a design

calculation method for the cross air blow would be

summarized firstly. The calculation of some

parameters provide sufficient theoretical basis for

the design of the device and ensure the rationality of

the windless area and the length of the blowing area,

such as cooling capacity, the volumetric flow of the

wind, the height of the air outlet, the inner and outer

diameters of the cross air blow head, the curve

equation of the pressure stabilizing chamberouter

wall. However, it’s difficult to calculate these

parameters due to the large number of parameters

and less research, the dependent variables between

parameters such as the length of the windless zone

and the blowing zone. On the basis of theoretical

calculation, the thermodynamic and kinetic

mathematical model of the complex system of the

cross air blow system would be established based on

the ansys simulation platform to study the different

wind pressure and wind speed distribution in the

cross air blow duct, as well as the relationship of

pressure difference between inside and outside of the

blowpipe. The rational air flow velocity and

temperature distribution would be studied by

simulating the entire spin cooling process to

establish a database between the functional structure

of the cross air blow system and the flexible

modified varieties to realize the flexibility

interchange between components and varieties.

4.2.2 Product Grouping Technology

The flexible modified varieties are grouped

according to the database between the functional

structure of the cross air blow system and the

flexible modified varieties to study the evolution of

fiber orientation and crystal structure in the process

of blowing. Designing flexibility with type-group

features can greatly reduce the workload of research

and design of flexible cross air blow systems, as

well as with the success or failure of flexible design

and with good technical and economic benefits.

Figure 3: The relation graph among Product Flexibility, Mechanical Flexibility, Process Flexibility, and Flexibility of

Control Systems.

4.2.3 Research and Design of Flexible Cross

Air Blow Device

The cross air blow device that can adjust

temperature and pressure would be designed

according to the distribution of the wind speed and

temperature in the cooling blower. Through the

selection of rectifying material and the design of the

air chamber, the cooling wind speed is ensured to be

stable, and the inner and outer layers of the tow are

cooled evenly. Wind temperature, air pressure, wind

speed, length of windless zone can be adjusted

according to the fiber to achieve modularity and

interchange ability of components and the cross air

blow device to meet the requirements of flexible

cooling in fiber production.

Figure4: The research roadmap of flexible cross air blow

device.

5CONCLUSIONS

Cross air blow device has shown the advantages in

terms of productivity, energy savings, and reduced

operating costson the spinning fine and ultrafine

fiber yarn. With the improvement of domestic

chemical fiber machining precision, domestic

production of cross air blow device has approached

or reached the international advanced level. The

cross air blow technology develops from single blow

heads, high damping and high energy consumption

to multiple blow heads, low damping, low energy

consumption, high efficiency and high blow quality.

However, there is still room for greater improvement

in avoiding overcapacity of general-purpose

products, increasing the differentiation rate of

chemical fiber products, and satisfying the

increasingly higher demands of users on the

consistency of product quality. It’s an urgent need to

break through the technology to achieve flexible

blow cooling and develop the small-batch and multi-

variety productsin the high-capacity continuous

equipment.

ACKNOWLEDGEMENT

Thanks very much for the support of the National

Key Research and Development Program

(2016YFB0302700), the Key Research and

Development Project of Jiangsu Province

(10317480) and the Fundamental Research Funds

for the Central Universities (18D110321) during the

project.

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