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Twisted Tube

Twisted tube is a kind of enhanced heat transfer tubes that firstly presented by Swedish Alards Company, and then improved by the USA’ Koch Heat Transfer Company, LP.

Fig.   Twisted tube


1. Structure and manufacture of twisted tube

Structure and manufacture of twisted tube

The manufacturing process of twisted tube includes:"partial pressure" and "distortion". The tube’s cross section is nearly an ellipse, of which the ratio of long axis and short axis is designed according to the flow velocity in tube passes and shell passes of heat transfer tubes. When the flow rate in tube pass is low, the ratio of the long axis and short axis shall be increased, or the flow surface shall be reduced in order to increase the flow rate.

2. Enhanced heat transfer principles of twisted tube

The unique structure of twisted tube can make the flow in tube pass and shell pass in the spiral motion at the same time, by this way it enhanced the turbulent intensity. The heat transfer coefficient of the twisted tube is 40% higher than the normal one, but the pressure drop are almost same.

3. Advantages of heat transfer with twisted tube


1Lower pressure dropNo baffle plate, lower pressure drop in the shell pass
2Higher heat transfer efficiencyIt can increase the turbulent intensity, make the shell flow velocity and the direction change regularly, and enhance the mixture in lengthways
3Less depositNo blind zone in the shell

Fig. Stereogram of Stainless steel twisted tube

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Fig. Brass, copper twisted tube

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Fig. Carbon steel twisted tube

Seamless steel twisted tubes used for producing heat exchangers are complete ones without joints. Common materials used in steel tubes shows in bellow chart.


Tab.  Material of tube

TypeNo.StandardSupply condition
Carbon steel10、20GB/T 9948-2006
GB/T 6479-2000
GB/T 8163-2000
Annealed condition
Nickel   
Titanium   
Alloy of copper   
Austenitic stainless steel0Cr18Ni9GB/T 13296-2002
GB/T 14976-2002
Pickling & passivation
00Cr19Ni10
0Cr18Ni10Ti
0Cr17Ni12Mo2
00Cr17Ni14Mo2

4. Specification of twisted tube


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Fig. Basic dimension parameter figure of twisted tube


Tab. Basic parameter of twisted tube

Spec.Lead St(mm)Long axis a  (mm)Short axis b (mm)Length of bare ends L1  (mm)
Φ8200  Arbitrary length
Φ16200  Arbitrary length
Φ1920023.013.0Arbitrary length
Φ2520030.515.5Arbitrary length
Φ3220037.022.5Arbitrary length
Φ38200  Arbitrary length

Note: The above table is the basic parameter of standard twisted tube. Twisted tube can be manufactured as the St and L, if there are special requirements.

5. Application of the Twisted tube

As twisted tube has been fast developed and improved in recent years, it is much more reliable and effective, which can almost be used in all kinds of shell and tube heat exchangers. More than 1000 twisted tube heat exchangers have been used since 1984, which can be used in gas-gas, liquid-liquid and liquid-gas heat transfer process, including chemistry, petroleum, food, papermaking, electric power, metallurgy, mining, and urban heating industries.


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Along Liu(Dr. General Manager): 0086-181 1736 2230
Production base: Jiuhua Town, Rugao City, Nantong City, Jiangsu Province, PRC
Business office: Business Park of Meimei, NO.168 Jixin road, Minhang district, Shanghai city, PRC
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