Ellipse Finned Tube Heat Exchanger for Drying System of Printing Machine

Ellipse Finned Tube Heat Exchanger for Drying System of Printing Machine

Oval tube finned tube heat exchanger in the printing machine drying system is the core heating element, its design features and printing drying process needs are highly adaptable to efficiently transfer heat to the printed materials (such as paper, film, etc.), to achieve rapid curing of ink, coating.

The core of the printing press drying system is to realize the drying of printed materials through hot air circulation:

Steam or high-temperature fluid (such as hot water, thermal oil) is passed into the base tube of the elliptical tube finned tube heat exchanger to release heat;

The heat is transferred through the wall of the elliptical tube to the external fins, and the fins quickly distribute the heat to the surrounding air by virtue of their large expansion area;

The fan will heat the air (usually at a temperature of 50-150°C, adjusted according to the type of printing materials and inks) and the air will be heated. The fan blows the heated air (usually at a temperature of 50-150°C, adjustable according to the printing material and ink type) onto the surface of the freshly printed substrate to remove the solvents (e.g., water, organic solvents) in the ink/coating through the convection heat exchanger to realize drying and curing;

part of the underutilized hot air is recycled into the heat exchanger through the recycling device to reduce the waste of heat.

Core Advantages of Elliptical Tube Finned Tube Heat Exchanger for Printing Drying Scenarios

High-efficiency heat transfer to meet the demand for fast drying

The flat structure of elliptical tubes reduces the resistance of the air flowing through the fins, which reduces the energy consumption of the fan and at the same time allows the hot air to pass over the surface of the fins more uniformly, and the heat transfer efficiency is increased by 10-20% compared with the traditional round tube finned heat exchanger.

The close bonding between the fins and elliptical tubes (e.g., high-frequency welding) reduces the contact and thermal resistance, which enables rapid response to the drying process. The close combination of fins and elliptical tube (such as high-frequency welding process) reduces the contact thermal resistance, which can quickly respond to the demand of drying temperature and avoid the problems of scuffing and dirtying, inadmissible overprinting, etc. caused by untimely drying of prints

Good uniformity of hot air, to protect the quality of printing

The arrangement of elliptical tubes (usually staggered) with the regular distribution of fins can make the temperature field of the heated air more uniform, to avoid local overheating leading to deformation of prints (such as wrinkles in the paper, film shrinkage) or discoloration of the ink;

Compared with other heat exchangers (eg, light tube, plate heat exchanger), the fins of the large area of the heat dissipation can reduce the temperature difference between the hot air (generally controlled within ± 2 ℃), to ensure the consistency of different areas of print drying. The large heat dissipation area of the fins reduces the temperature difference of the hot air (generally within ±2℃) and ensures the consistency of drying in different areas of the print.

Compact structure, adaptable to the space limitation of the printing machine

The flat design of elliptical tube saves more space than round tube, and with high-density fins, it can realize large heat exchange area in the limited cavity of the drying box of the printing machine (usually with narrow width), which can satisfy the demand of “small space, high heat”.

Strong vibration-resistant performance can adapt to the slight vibration of the printing machine when it is in high speed, avoiding the fins from loosening or vibrating. Strong anti-vibration performance, can adapt to the slight vibration when the printing machine is running at high speed, avoiding the fins loosening or tube deformation.

Temperature and environmental resistance to match the printing scene

Printing drying temperature is usually 50-150 ℃, elliptical tube finned tube (especially stainless steel) can stably withstand the thermal stress of this temperature range, and resistant to ink volatiles (such as a small amount of organic solvent vapor) of the slight corrosion;

If the printing workshop there is paper dust, ink particles, elliptical tube streamlined structure compared to the round tube is less prone to dust accumulation (to reduce the dead space of the dust adherence), to facilitate the cleaning and maintenance of later. The streamlined structure of the oval tube is less prone to dust accumulation than the round tube (less dust adhering to the dead space).

Oval tube finned tube heat exchanger on the printing process of the key role of to enhance the drying speed, matching the production capacity of the printing press

printing press running speed (such as gravure printing machine can be up to 300-600 m / min) requires drying system in a very short period of time to complete the ink curing. The high efficiency of the elliptical finned tube heat exchanger heats the air to the target temperature (e.g. 80-120°C for film printing), ensuring that the solvents evaporate as the print passes through the drying zone and avoiding sticking during winding.

Protect the physical properties of printed materials

Paper, film and other substrates are sensitive to temperature, overheating is easy to cause dimensional changes (such as paper expansion). The elliptical tube finned tube heat exchanger's uniform heat dissipation characteristics can accurately control the temperature of the hot air, with temperature sensors to realize closed-loop regulation, reducing the print waste caused by temperature fluctuations.

Reduced energy consumption and environmental requirements

The printing industry has high energy costs and environmental requirements. The elliptical tube's low flow resistance design reduces fan power consumption, while the high efficiency of heat transfer reduces steam/heat source consumption (15%-20% energy savings compared to traditional heat exchangers) and indirectly reduces carbon emissions.