A convector for cooling of a fluid circulating in a pipe

Technical field The present invention relates to a convector for cooling a liquid circulating in a pipe according to the preamble of claim 1, for example in a pipe carrying a cooling liquid flowing from a plastic processing plant. The convector comprises at least one set of finned pipes in which said cooled liquid will circulate, and at least one fan which is the source of an air stream hitting the outside of said finned pipes to cool the liquid. Such a convector is known from EP-A-1

477 756.

BACKGROUND OF THE INVENTION [0002] A common method to increase the convector's cooling capacity, which reduces the temperature of the working fluid supply even below ambient temperature, is to spray the convector pipe set with nebulized water, which during evaporation into the air stream generated by the fan lowers the temperature of said air stream and thus also working liquid temperature: Nevertheless, the evaporating water leaves sediment from accumulated salts, e.g. limestone and others, on the set of pipes and their fins. Deposition of salt during long-term use results in a decrease in convector heat exchange capacity, and hence, requires costly maintenance and / or earlier demineralization of nebulized water, which results in increased costs. Existing systems are always equipped with a recirculation system for nebulized water that has not yet evaporated, with a suitable bleed valve to maintain salt concentration at acceptable levels. Objects and summary of the invention [0003] The present invention aims to avoid these drawbacks by means of a convector according to claim 1. According to the invention, the convector comprises a chamber through which the convector air flow passes, and which is upstream of said set of pipes with respect to the air flow direction. Inside the chamber, water nebulization is carried out via spray nozzles. According to the invention, the chamber - hereinafter referred to as the "adiabatic chamber", because the heat exchange between the air stream and the chamber walls is negligible - is defined by the side walls and at least two steam-filled packages located in the chamber at the beginning and end of the chamber, in air flow direction through the chamber. Preferably, said packages are filled honeycomb shaped packages. Nebulized water, which does not evaporate directly inside the chamber, moisturizes the entire large cell surface of the mentioned honeycomb packages and continues to evaporate there. In this way, the injected water absorbs the heat of evaporation from the air stream, cooling said stream before it passes through the set of pipes and thereby lowering the supply temperature of the working liquid.

[0004] According to a preferred embodiment of the invention, the convector comprises control means for controlling the flow rate of nebulized water injected into the adiabatic chamber depending on the temperature and / or humidity of the ambient air, and / or the temperature of the working liquid and / or the flow rate of the stream air generated by the fans in such a way that all the injected water evaporates in the chamber and the filled packages in the shape of honeycombs, which will prevent the pipe sets from getting wet and dispersed into the environment. [0005] In this way, demineralization or recycling of water is not necessary and salts do not deposit on the finned tube sets. The only maintenance required is periodic cleaning or replacement of the honeycomb filled packets on which salts contained in the injected water are deposited. These packages - whose cost, due to their form, is limited - are available on the market and consist of many thin plastic sheets placed side by side and partly connected with each other, the layers being folded in such a way as to form numerous channels small diameter, which can be used for air generated by convector fans. In this way, the water particles that are still in the liquid state supplied from the adiabatic chamber settle in the channels of the filled honeycomb shaped packets, characterized by a deviation of direction and a relatively large contact surface with the air stream, which promotes evaporation.

[0006] Said convector control means according to the invention may include ambient temperature and humidity sensors connected to the control circuit, and a valve for regulating the flow rate of nebulized water operated by said control circuit to ensure complete evaporation of the water before it reaches the set of finned pipes .

[0007] In addition to the packages at the beginning and end of the chamber, the adiabatic chamber may further comprise between them other spaced apart steam-filled honeycomb shaped packets, the water injection nozzles being positioned between one or more pairs of said adjacent filled packets . Said nozzles preferably spray water in the opposite direction to the air flow inside the adiabatic chamber. Brief description of the drawings [0008] The invention will be better understood by means of the following description with the accompanying drawing, which is only a non-limiting example of said invention. In the drawing:

Figure 1 is a side view of a convector with five fans with the side cover panel partially removed;

Figure 2 is a view of the convector along the line II-II in Figure 1;

Figure 3 is an enlarged cross-sectional view of the convector along the line III-III in Figure 1;

Figure 4 is an enlarged cross-sectional view taken along the line IV-IV in Figure 2;

Figure 5 shows an enlargement of detail V in Figure 3; and

EP 1 920 207

Figure 6 shows an enlargement of detail VI of Figure 5.

Detailed description of an embodiment of the invention [0009] With reference to Figures 1 and 2, a convector for cooling a liquid circulating in a pipe comprises a structure with five adjacent modules, such as a module designated by reference numeral 1, and equipped with vertical legs 3 resting on the ground, wherein the modules are separated by metal panels laterally from each other and from the external environment. From left to right (with reference to Figure 1) a pair of finned pipe sets 7 (see also Figure 3) arranged in the shape of the letter V pass through the entire set of modules 1, the sets of pipes are equipped with inlet and outlet pipe branches at the ends, marked with 7A and 7B (see also Figure 4), in which the fluid communicates with sections 9A and 9B of the branch of the supply and delivery pipe, respectively, in which the refrigerated liquid circulates.

[0010] Each module 1 comprises a vertical axis fan 11, shielded from above by a grate 11A, which produces an air stream flowing according to arrow F1 (Figure 1), passing from below upwards through the module and successively through the respective piece of pipe set 7. Pipes the pipe set 7 has fins 7C (Figure 4) to increase the heat exchange between the circulating liquid and the air stream produced by the fan 11.

[0011] According to the invention, each convector module 1 has - located upstream of the pipe set 7, in relation to the direction of air flow according to F1 - a chamber 13, called an "adiabatic chamber", limited laterally by panels 5 and in the flow direction F1 limited at the inlet filled with packet 15 and placed at the outlet filled with packet 17. (See also Figure 5.) The filled packets 15, 17 may preferably be honeycomb packets. In a known manner, the filled packets, and in particular the filled honeycomb packets, are made of corrugated or wrinkled L plastic layers, said layers being placed next to each other and glued together to form, with appropriate corrugations, a series of small tubes inclined from the vertical, suitable for this, to allow the air stream to flow along the F1 direction and provide a large contact surface with said jet. Passing through the assembly of modules 1, at the level of the respective adiabatic chambers 13 there is a pair of water supply pipes 19, to which in each chamber 13 sprayers 21 are connected, in fluid communication with said pipes 19. The pipes 19 contain water under pressure, e.g. 2-4 bar, and the atomizers 21 (see Figure 5) have respective nozzles 21A downward, i.e. in the opposite direction to the airflow direction F1. Nozzles 21A have a relatively small diameter, for example, several tenths of a millimeter, to very accurately nebulize water inside the adiabatic chamber.

[0012] The convector also includes a controller for the flow rate of nebulized water flowing in the pipes 19, depending on the speed of the fan 11 (and thus also the flow of air flowing along the F1), and / or the temperature and humidity of the ambient air and / or the temperature of the working liquid determined by special sensors (not shown

EP 1 920 207 in the drawings). The controller, e.g. by timing the special on / off valve, differentiates the water flow rate in such a way that:

- water that is finely atomized inside each chamber 13, and which - carried by the air stream along the F1 direction - moisturizes the tubes of the filled package 17, completely evaporated at the outlet of the package in such a way that the air stream supplied from the filled package 17 does not contain particles liquid water, thus avoiding moisture in the pledge of the finned pipes 7 and the accumulation of salt deposits on them;

- the water that flows into the inlet adiabatic chamber packet 15 has completely evaporated before reaching the inlet of the packet 15 being filled by gravity, thereby avoiding the water falling and dispersing on the ground.