u bending, bend tube, stainless steel pipe bend

Many heat exchangers are U-shaped to maximize tube surface and heat exchange in a confined room. A u-tube heat exchanger or let’s say a u-tube configuration also makes it simple to enter the package. This article will provide readers with an introduction to one of the most common heat exchangers, the u-tube heat exchanger.

What is u-tube heat exchanger?

U-tube heat exchanger is a form of tube and shell heat exchanger that is used in petroleum and chemical machinery. The tube box, casing, and tube buddle are the key components of a u-tube heat exchanger. Furthermore, drying is simple following the hydro test of the u-tube heat exchanger.

Both of the front header types may be used in a u-tube heat exchanger, and the rear header is usually an M-Type. The U-tubes allow for limitless thermal expansion, the tube bundle may be removed for cleaning, and small bundle-to-shell clearances are possible. However, since mechanical cleaning of the tubes is difficult, this type is normally used only when the tube side fluids are clean. The u-tube design has the drawback of not being able to provide pure counter-flow unless an F-Type Shell is used. Besides, u-tube designs are limited to an odd number of tube passes. This can be one of the disadvantages of u-tube heat exchanger.

On the other hand, about u tube heat exchanger advantages we need to say that the benefits stem from its compact size, which is also very powerful. Because of the U-shape, heat stress can be accounted for. A heat exchanger with U-tube packages takes up slightly less volume than a straight tube heat exchanger of the same design due to the bent individual tubes. Here also the concept of u tube vs straight tube heat exchanger comes to the scene. During the action, u-tube heat exchanger often provides only a low-pressure loss. Stainless steel can help to reduce corrosion and deposits. As a result, the number of repair cycles is greatly decreased. Additionally, a worn tube package may be replaced. If the input temperatures of the two media are very different, the material and construction must withstand extremely high heat stresses. As a result of the temperature differential, the metal expands at different points and to different extents, and cracks will form if the design is flawed. Because of the U-shape of the tube bundle, the heat exchanger can adjust for certain heat pressures very well and is hence well suited for operation with two output media at very different temperatures. Baffles are used in tube package heat exchangers to improve heat exchange.

Yes! There are more about u tube vs straight tube heat exchanger. Any manufacturer would have to decide whether to use a straight tube or a u-tube exchanger. The construction of the tube is important. If a manufacturer selects a tube design that is not appropriate for the application, it can result in exchanger damage or difficult-to-clean fouling. Both u-tube heat exchanger and straight heat exchanger are widely used in a variety of sectors, including food and beverage, chemical, and pharmaceuticals, and each has its own set of benefits and drawbacks. Except for the tube configuration and the rear bonnet, they are similar.

Let’s discover the advantages of straight tube heat exchanger first.

Advantages of straight tube heat exchanger

One of the most significant advantages of the straight tube heat exchanger is its simplicity. Straight tube exchanger is also common because of its flexibility. Straight tube exchanger allows for pure countercurrent flow within the exchanger without the need for a second one to be connected in series to the first. An F-type two-pass shell with a longitudinal baffle is favored over an E-type in these situations. The baffle divides the two currents. As the cold and heat streams travel in opposite directions, this is referred to as countercurrent movement. For all stages in the exchanger, the hot stream should be colder than the cold stream, though the cold stream’s exit temperature might be greater than the hot stream. Co current flow, on the other hand, defines the passage of hot and cold streams in the same direction. The cold stream must always be lower than the hot stream in this setting. This means that the cold stream’s outlet temperature must be slightly lower than the other. This is impossible to do when the streams are going in the same direction, so many manufacturers resist co current designs.

u tube heat exchanger advantages

Although straight tube heat exchanger has many advantages, it can fall short in certain ways. This is one of the reasons why the u-tube heat exchanger is so popular. While a straight tube design is safer since the tubing does not need to be curved, as with U-tubes, it can become very expensive when other necessary additions are considered. U-tubes, for example, need only one tube sheet and bonnet, resulting in significant cost savings.

Straight tube heat exchanger is vulnerable to the thermal expansion effect. As the tubes heat at varying speeds and pressures, it does not necessarily spread in sync. Since the tubes are attached to these other critical materials, this may cause damage to the tube layer and shell in a straight tube exchanger. This problem can be alleviated with an extension joint, but these additions are not inexpensive. A u-tube heat exchanger, on the other side, is only attached to the tube sheet and shell on one end, allowing for thermal expansion without causing damage to the rest of the system. Tube packets can also be conveniently separated from the exchanger thanks to U-tube designs. This makes it easier to examine and disinfect the shell and exterior of the tube bundle.

Cleaning is another important factor for designers to remember when designing an exchanger. Straight tubes are the simplest to vacuum when there are no twists to contend with. However, some straight tube designs make testing and cleaning of the shell more complicated because the tubes cannot be.

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U bend tubes for heat exchangers applied mostly in oil and gas plants, chemical and petrochemical plants, refineries, power plants and renewable energy plants. Low fin tubes can be supplied in the form of U bends.

Each U bend tube of our range is rigorously quality checked by our team of talented professionals on every stage of production to deliver the clients defect free best quality products. These U bend tubes can be custom designed in various diameters as per the requirements of our clients.

U tube heat exchanger

U-bend tubes are widely used in heat-exchanger systems. Heat-exchanger equipment on the basis of seamless stainless U-tubes is essential in strategically important and critical fields — nuclear and petrochemical machine building.

“U bend tubes for heat exchangers applied mostly in Oil & Gas plants, Chemical & Petrochemical plants, Refineries, Power plants, Renewable energy plants.”
  • Object medium: 10%sodium hydroxide+5%sodium hypochlorite
  • Shell Diameter: ø 800
  • Working Pressure: 1.5mpa
  • Working Temperature: 40º C~90º C
  • Heat Exchange Surface Area: 100M2
  • Material: Gr1\Gr2

Fin tube

Fin tubes are used in applications involving the transfer of heat from a hot fluid to a colder fluid through a tube wall. Furthermore, finned tubes are used when the heat transfer coefficient on the outside of the tubes is appreciably lower than that on the inside.

Note:
We produced condenser tube, carbon steel by the material out into the condenser tube, stainless steel condenser tube and carbon steel and stainless steel tubular mixed condensation out of three, according to the form of fixed tube plate, floating head type, U-tube heat exchanger, according to the structure into a single tube, twin-tube and multi-way tube, heat transfer area of 1 ~ 500m2, can be customized according to user needs.

U Tube Heat Exchanger

U tube heat exchanger is a kind of tube and shell heat exchanger, belongs to the petroleum and chemical equipments. This kind of heat exchanger is named after the‘U’shape tube. U tube heat exchanger is composed of some main components like the tube box, shell, and tube buddle. What’s more, it is easy to drying after the U tube heat exchanger hydrotest.

U Tube Heat Exchanger Advantages

  • The tube buddle can expand or contract freely, and they will not produce thermal stress due to the temperature difference between the tube and shell, which leads a good thermal compensation performance.
  • The structure is simple, with only one tubesheet and less sealing surface, thus,the price is low.
  • It is easy to make the u tube heat exchanger cleaning and maintenance, which is because the tube buddle can be drawn from the shell body.
  • This kind of heat exchanger has a light quality, is suitable for the situation with high temperature and high pressure.
U Tube Heat Exchanger Structure

U Tube Heat Exchanger Design

The biggest difference about u tube heat exchanger compared with other types of heat exchanger is the tube buddle structure, the longer the tube diameter is , the longer the minimum bending radius is. And the u tube heat exchanger bending radius should not less than two times the outer diameter of the heat exchanger tube.
U tube heat exchanger usually designed according to the ASME Code, Section VIII, Division 1. This high load U tube heat exchanger can prevent the stress damage caused by container inflation during the process of heating or cooling. As one end of the tube bundle is float, the heat exchanger can be guaranteed safety even under the extreme heat cycle. It is a ideal design method when the heat medium is steam.
ANSON can manufacture U tube heat exchanger in accordance with the ASME standard, TEMA, and API for 1, 2, or 4 pass U tube heat exchanger, other special requirements are also available.

TEMA Designations for Shell-and-Tube Heat Exchangers
 Stationary Head Types Shell Types Rear Head Types
A

channel and removable cover

E

one pass shell

Lfixed tubesheet
like ‘A’ stationary head
Bbonnet (integral cover)Ftwo pass shell
with longitudinal baffle
Mfixed tubesheet
like ‘B’ stationary head
Cchannel integral with
tubesheet and removable cover
Gsplit flowNfixed tubesheet
like ‘C’ stationary head
Nchannel integral
with tubesheet and removable cover
Hdouble split flowPoutside packed floating head
Dspecial high pressure closureJdivided flowSfloating head
with backing device (split_ring)
  Kkettle type reboilerTpull through floating head
  Xcross flowUu tube bundle
    Wpacked floating tube sheet
with lantern ring
      

  Ordering Information:

  • Please specify the type or standard you need, ASME standard or TEMA type. If you want a TEMA type heat exchanger please specify the type according to the above TEMA designation table, like TEMA Type BEM.
  • Please specify the material you need, we provide material from Steel, Stainless Steel to Copper Alloys. Other material options are also available.
  • Please specify the size you need. Like 1, 2, 4 or 6 pass and shell diameter, or other important dimensions you think

Products

U-Bend Tubes for heat exchanger

U-Bend Stainless Steel Tubes Package

‘U’ Bend Stainless Steel Tubes are manufactured in our plant as per the customer requirements. Bends can be Heat Treated in accordance with Clients’ requirements followed by hydrostatic testing and dye penetrant testing if required.

U bent tubes are widely used in heat-exchanger systems. Heat exchanger equipment on the basis of stainless U-tube is essential in strategically important and critical fields nuclear and petrochemical machine building.

U-tube heat exchangers Designed for high temperature applications, especially steam condensing or hot oil systems. Thïs model is selected when differential expansion makes a fixed tube sheet exchanger unsuitable and when conditions preclude a floating head type (HPF) selection.

Surface condition Finished U-tubes shall be free of scale, without scratches after bending

Dimensional tolerances U-tubes acc. to TEMA R.C.B.

Length of straight part -0/+5 mm
Flattening (also called “ovality”) at the bend shall not exceed 10% of the nominal tube outside diameter.
Wall thickness in bending part acc. to TEMA RCB 2.31 Minimum tube wall thickness in the bend part (T min)T(min) ≥ (SW × (2×R + D))/( 2× (R+D)where:

SW is smallest wall thickness D Nominal outside diameter R radius
Radius tolerance 1) for R 100 mm +/- 3 mm

2) for R ≥ 100 mm +/- 5 mm
Straightness tolerance max. 1,5 mm per 1 m
U-Tube ends: plain, vertically cut to the tube axis

Tube-bending line, installed at 2007, will allow to produce U-tubes as per such standards:

1. ASTM A688/A688M-08
2. ASTM A803/A803M
3. ASTM A556/A556M, ASME SA556
4. ASME SA-688

Initial Length
Maximum lengths of 27000mm can be supplied on request

Dimensions
Tubes OD in mm can be bent upon agreement: 15,8 – 16,0 – 17,0 – 18,0 – 19,05 – 20,0 – 21,3 – 25,4 -26,7 – 31,8 -38,1

Bending radius
Minimum: 1.5×OD
Maximum: 1500 mm

Heat treatment of the bend
U-bends with a bending radius up to maximum of 1500mm can be heat treated on request

The basic Testing and processing:
1. High Pressure Hydrostatic Test:Minimum:10 Mpa-25Mpa.
2. Air Under Water Test After Bending
3. U Tubes Wall Thickness Test
4. Eddy Current Test before U bend Formed
5. Ultrasonic Test before U bend Formed
6. Heat treatment to stress relieved
7. Ball passing test

The below sizes are those most frequently used,other sizes can be produced upon request.

Grade(UNS):Austenitic Stainless Steel:
304/304L/304H(1.4301/1.4306/1.4948); 316/316L(1.4401/1.4404); 316Ti(1.4571)

321(1.4541); 309S(1.4833); 310S(1.4845); 317L(1.4438)321H(1.4878); 347H (

1.4550);

Duplex Stainless Steel:
S32001, S32003, S31500, 2205(1.4462); S32304,(1.4362);S31803,2507 (S32750),S32760(1.4501)

;S32101(1.4162);

Super Austenitic Stainless Steel: 904L, S30432, S31042, 6Mo (S31254, N08367

)

Nickel Base Alloys:
Alloy 20 (UNS N08020), Monel 200 (UNS 02200), Monel 400 (UNS N04400),

Incoloy 800 (UNS N08800), Incoloy 800H (UNS N08810), Incoloy 800HT (UNS N08811), Incoloy 825 (UNS N08825),Inconel 600 (UNS N06600), 4J29, 4J36, GH3030, GH3039, C276 (UNS N10276)

Martensitic Stainless Steel:410(1.4006), 410S(1.4000), 420(1.4021)

Ferritic Stainless Steel:405(1.4002), 430(1.4016)

Outside Diameter:6 – 830mm
Wall Thickness:0.50 – 60mm
Standards(Norm): EN 10216-5DIN 17456, DIN 17458, DIN 2462, DIN 17455
 GB/T14975; T14976; T13296; GB5310;
 ASTM A213A269A312A511A789A790A928, A999, A1016, ASTM B161, ASTM B163, ASTM B165, ASTM B167, ASTM B338, ASTM B407, ASTM B423, ASTM B444,ASTM B619, ASTM B622, ASTM B626, ASTM B668, ASTM B677, ASTM B829
 JIS G3459, JIS G3463, JIS G3446, JIS G3447, JIS G3448, JIS G3468
 GOST 9940;GOST 9941;

Your best solution in Heat Exchange solution!
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