U-shaped heat exchanger tubes

U-shaped heat exchanger tubes are a type of shell and tube heat exchanger that have a tube bundle made of continuous tubes bent into a U-shape.

The bend side is free-floating and this helps in thermal expansion without requiring expansion joints. U-tube heat exchangers have a simple structure which makes them easy to manufacture and maintain. They are commonly used in shell and U-tube heat exchangers.

U bent heat exchanger tubes are used in various industrial applications for heat transfer between fluids, such as in boilers and condensers. U bent heat exchanger tubes are made from a variety of materials including stainless steel, titanium, and copper alloys depending on the application and environmental factors. They are typically designed to withstand high temperatures and pressures and are used in both liquid and gas applications.

Both ends of the U-tube are fixed on the same tube plate, and the shell and heat exchange tubes are separated. This allows the tube bundle to freely expand and contract without generating temperature difference stress, which is a problem that can occur in other types of heat exchangers.

U-shaped heat exchanger tubes have a simple structure which makes them easy to manufacture and maintain. They are commonly used in shell and U-tube heat exchangers, which consist of a cylindrical shell with U-shaped tubes inside. The U-tube design allows for better heat transfer efficiency, and the compact size of the U-shaped tubes means that the heat exchanger can be very powerful despite its small footprint.

Overall, U-shaped heat exchanger tubes are a popular choice for many industrial applications due to their simplicity, efficiency, and compact size.

U-tubes are made of precision straight tubes. These precision straight tubes are completed after cold rolling and bright annealing. In order to meet the technical conditions of our customers, every step of the process is strictly controlled.

U-tubes are mainly divided into two categories according to materials: stainless steel U-tubes and alloy steel U-tube

Measuring, cutting, deburring and cleaning of U bent tube

• U-bend pipes are measured exactly in accordance with relevant standards.
• All U bend pipes are cut to the specified leg lengths, ends are deburred and the u bend tubes are internally cleaned with air.
• Before packing, both ends of U-bend pipes are capped with plastic caps.

U-tube explanation

a...................The difference in length between two straight pipe sections
c..............The tangent spacing of the outer wall of the elbow
Da............nominal steel pipe outer diameter
E..............The distance between the outer diameters of the two straight ends
f...............the distance between the ends of the two straight ends
l............... straight tube length
Lg............. straight pipe section plus total length of pipe
Rm...........nominal bending radius
S.............nominal wall thickness
Smin.......The minimum wall thickness at the back of the elbow
t...............the bend deviates from the horizontal distance
So...........Standard minimum wall thickness

Drawing

Heat treatment

If requested by the customer, we add a straight pipe section with a minimum of 150mm according to the elbow.
Heat treatment is performed.

The computer controls the heat treatment furnace and records all the data.
The tube is filled with a protective gas - argon.

We can provide all the forms of annealing

• Solution annealing
• Stress relief annealing
• Stabilized annealing

Technical Parameters

Outer diameter: 12.7-38 mm
The bending radius is from 1.5 times the outer diameter to 1250 mm. The outer diameter is over 28mm,
The minimum bend radius can be further discussed.
Straight pipe length is the shortest 1000mm
Straight pipe length up to 12000mm
The bending radius is below 1000mm and heat treatment is required.

Bent pipe technology standard

• Technical Standard 7-2-1179
• DIN 2879, TEMA RCB 2.31
• Can be specified according to customer requirements. Can also follow some general techniques Specifications.

Hydrostatic test

• All U-tubes are subjected to a hydrostatic test after heat treatment.
• The test time is not less than 5 seconds at the set pressure.
• All tubes were blown dry and carefully cleaned after the test.

Measuring, cutting, deburring, cleaning

• Accurately measure U-tubes according to relevant standards or customer requirements.
• All pipes should be cut to length, deburred, and air dried to the inner wall.
• Seal the ends with a plastic cap before packing.

Packing for U bend Tubes

We packs all U Tube bundles in bespoke wooden boxes and separate all U Tubes of different radii using finger pallets to facilitate easy assembly of bundles on receipt.

Any type of packing is available according to customer need to worldwide destinations.

• For roadfreight in timber fingers or skids.
• In strong open or closed wooden boxes depending destination.
• Each bundle is protected with plastic sheets.
• Customers can provide their own packing or Salem can prepare a packing plan.
• Detailed packings lists are attached to wooden cases to give quick and clear identification of contents.

Standard for U-shaped heat exchanger tubes

The semi-finished product for U bend tubes are heat exchanger tubes, manufactured and supplied according to DIN 28180 and ASTM A179.

Tubes for heat exchangers are made of steel according to:

Chemical Composition and Mechanical Properties (Part)

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.

U-Bend Fabrication Tolerances

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.