Air finned tube radiator construction and cleaning

Air finned tube radiator construction and cleaning

Structure of air finned tube radiators

The air finned tube radiator is mainly composed of a tube bundle, a ventilator and a frame. 3 parts. The tube bundle includes heat transfer tubes, tube boxes, side beams and cross beams etc. It can be arranged in 3 basic forms: horizontal, vertical and sloping top. Among them, the horizontal arrangement has a large heat transfer area, uniform air distribution and good heat transfer; when the sloping top arrangement is used, the ventilator is installed in the central space of the herringbone, covering a small area and having a compact structure.

 To offset the effect of the lower heat giving coefficient on the air side, tubes with fins on the outer wall of the light tube are usually used. The finned tubes are used as heat transfer tubes to expand the heat transfer area. The finned tubes are arranged in layers and their ends are connected to the tube box by welding or expansion methods. The rows of tubes are generally 3-6 rows of tube bundles in series sizes up to 30 metres. The outer diameter of the light tube is often 25 mm and 38 mm, the fin height is generally taken as 12-15 mm and the width is 505-2375 mm.

 The finned tube is the core element of the air finned tube radiator and its form and material directly affects the performance of the equipment. The tubes can be made of carbon steel, copper, aluminium and stainless steel; fin materials are determined according to the use of the environment and manufacturing process, mostly with industrial pure aluminium, in the case of high corrosion prevention requirements or in the manufacturing process conditions are also used copper or stainless steel.

 The fins can be arranged horizontally or vertically. The basic forms of finned tubes are: winding type, inlay type, rolling type, sleeve type, welding type, elliptical tube type, turbulent flow type (including spoke type, slotted and corrugated type, etc.). The structure of the pipe box mainly has flange type, pipe plug type and collection pipe type. The former is generally used for low and medium pressure, and the latter two for high pressure. In order to adapt to the thermal expansion of the tube bundle, one end of the tube box is not fixed, allowing for displacement along the tube length.

Areas of application of air finned tube radiators

Refining and petrochemical tower top vapour condensation; reflux oil, tower bottom oil cooling; cooling of various reaction products; cooling of circulating gases and condensation of power station turbine exhaust.

Cleaning of air finned tube radiators

Because most of the cooling water contains calcium, magnesium ions and acid carbonate. When the cooling water flows through the metal surface, there is the generation of carbonate. In addition, the oxygen dissolved in the cooling water also causes corrosion of the metal and the formation of rust. As a result of the rust scale, the heat transfer effect of the condenser is reduced. In severe cases, the cooling water has to be sprayed outside the shell and the scaling can be serious. Blocking the tube, making the heat exchange effect useless.

 Studies have shown that scale deposits have a huge impact on heat transfer losses, and as the deposits increase they can cause energy costs to rise. Even a very thin layer of scale can increase the operating costs of the scaled part of the plant by more than 40%. Keeping the cooling channels free of mineral deposits can go a long way to improving efficiency, saving energy and extending the life of the equipment, while saving production time and money.

 For a long time traditional cleaning methods such as mechanical methods, high pressure water, chemical cleaning, etc. in the cleaning of equipment there are many problems: can not completely remove scale and other deposits, acid corrosion of equipment to form loopholes, residual acid on the material to produce secondary corrosion or corrosion under the scale, eventually leading to the replacement of equipment, in addition, the cleaning waste liquid is toxic and requires a lot of money for wastewater treatment.