IMPROVEMENTS TO AIR-CONDITTONING PLANT

Technical Field

The present invention relates to an air conditioning plant and in particular of heat exchangers in which, the feed of the intended fluid, for example Freon, to the bundle of tubes within the heat exchanger is performed by a distributor that comprises a main fluid supply pipe that leads into a distributor chamber from which there lead off various short ducts equal in number but slightly smaller in diameter than the tubes of the heat exchanger to be supplied, in such a way that every tube of the tube bundle to be supplied with the fluid, which comprises the heat exchanger, is supplied directly in equal measure to the other tubes.independently of its position in relation to the main supply pipe. Background Art

Air conditioning plant can be classified according to intended use as either "civil ^" ' or "industrial". The former type is used in theatres,cinemas, hospital, hotels, offices, private dwellings etc. and is intended to maintain conditions, of temperature and air purity in

the environments frequented by people and with a wiew to their well being that are better adapted health-wise to the uman organism than those conditions that establish themselves naturally. The latter type is used to obtain artificially specific environmental conditions that make possible or improve the manufacture of products the characteristics or quality of which are influenced by the temperatture and humidity of the ambient air,such that, independently of the weather outside, the manufacturing process can continue regularly throughout the year. Air conditioning plants include .in outline, fans to produce conditioner air.cooiing and heating batteries, filters and humidifiers, control shutters, automatic control device, connecting pipes and taps.

The plant is completed by a cooling group to produce cooling and for summer operation, a boiler to produce hot water or steam for winter operation and openings for delivery of the conditioned air or extraction of recycled air.

A fundamental component of the air- conditioning plant is the heat exchanger, which is substantially a device that achieves exchange of heat between two fluids, Generally ,the heat exchangers in use

consist of a set of tubes inside a casing that is generally cylindrical.

The cooling fluid circulates in the tubes, while the other fluid circulates within the cylindrical casing tha contains the tubes. The circulation of the fluid within the tubes is designed in such a way as to make it run the lenght of the exchanger two of four or more times, while the fluid around the tubes follows a zigzag route between the tubes.guided by diaphragms located at right angles to them.

Although they function, such heat exchangers give a low yield as a result both of the poor distribution of the fluid within the tubes by the means used to feed in the fluid circulating within the tubes, and because of the poor circulation of the second fluid outside the tubes within the container.

At present, distribution of the fluid into the tubes is from a diffuser located near the start of the tube bundle to be fed and which .thanks to one or more deflectors, distributes the fluid towards the entrance of the tubes. With this device the fluid is certainly distributed into the tubes on the same axis and closest to the outlet, whereas those furthest away and which can be reached only by the fluid deviated by the deflectors inevitably receive less fluid.

The second fluid ,which must circulate between the tubes of the bundle to achieve the exchange of heat, also encounters difficulties of circulation due both to distribution of the diaphragms located

transversely to the tubes and which create the route the fluid is obliged to follows between the tubes- and to the shape of the internal part of the container wich causes bad circulation of the second fluid ,to the point where it may be stagnant in some parts of the container.

It si clear that what has been described causes a marked fall in the yield of the heat exchanger, which at present must be over dimensioned in order to ensure that the needs of the plant are met. In order to overcome the problems mentioned .some improvements have been made to heat exchangers in respect to the device for distribution of the fluid within the tube bundle and the circulation and distribution of the fluid between the tubes as well as in the internal part of the outer casing, which make it possible to considerably increase the yield of the heat exchanger .at same time redcucing the noise level. Disclosure of Invention

According to the invention .the feed of the intended fluid .for example Freon. to the bundle of tubes within the heat exchanger is performed by a distributor that comprises a main fluid supply pipe that leads into a distribution chamber from which there lead off various short ducts equal in number but slightly smaller in diameter than the tubes of the heat exchanger to be supplied, in such a way

that every tube of the tube bundle to be supplied with the fluid, which comprises the heat exchanger, is supplied directly in equal measure to the other tubes, independently of its position in relation to the main supply pipe.

A second object of the invention is that of improving the circulation of the second fluid within the outer casing of the exchanger which enclose the tube bundle in such a way that the exchange of heat take place in a constant and uniform manner.

According to the invention, in proximity to the inlet and outlet of the fluid that circulates betwen the tubes, deflectors are arranged that have an inclination that starts form the perimeter of the inlet towards the nearest bulkhead which traverses the piping, thus preventing the second fluid . for example water, from dispersing at the entrance .oblinging it to channel itself in a direction transverse to the whole tube bundle. The second fluid for example water .then follows an imposed course .as is usual , determined by a series or bulkheads parallel to the first, which are arranged between the tubes at regular intervals at right angles to their longitudinal axis. According to the invention the tubes are arranged within the outer container in such a way that, seen from the front, the tubes in each bundle present an external perimeter similar to a square or rectangle such that , disposing of two longitudinal walls , one per side, within

the container, parallel to the horizontal axis of the container that passes through the inlet, one reduces the internal curvature of the outer container of the tubes, increasing the force of the fluid that passes through it and avoiding dead zones in the pripheral tubes where the fluid either does not arrive or stagnates, compromising heat exchange between the fluid that circulates within the tubes and that which circulates around them .

Again for the same reason described above, the opposite extremity to that for the feed to the tubes, a second bulkhead is positioned that follows the form of the outside of the tubes, forcing the fluid to circulate faster and preventing it being wasted in zones where tubes are not present.

What has been said in summary to this point can be better understood from the detailed description that follows, given with reference to the drawings attached in which :

Brief Description of the Drawings

Figure 1 shows a view in vertical section of the heat exchanger of which in the present invention.

Figure 2 shows a view in horizontal section of the heat exchanger of wich in section 1.

Figure 3 shows a front view of a possible arrangement of the tube

bundles within the heat exchanger.

Figure 4 shows a front section of the heat exchanger

Figure 5 shows a view in plan of the feed diffuser of the fluid into the tubes

Figure 6 shows a section of the feed-diffuser of wich in figure 5

Figure 7 and 8 shows possible variants of the feed diffuser of the fluid into the tubes.

According to the present invention, the heat exchanger comprises a set of tubes arranged as can be seen in figures 1 and 2, in such a way that the fluid with which they are fed runs the whole length of the exchanger twice.The tubes 1 are arranged within an outer shell

2 substantially cylindrical in shape and closed at one end by a round cover 3. while it is closed at the opposite end by the assembly formed by the feed diffuser 4. In proximity to the feed-diffuser block, on the upper part of the casing, there is the hole 5 by which the second fluid, for exmple water, enters, while in approximate correspondence with the cover 3, the outlet 6 of the second fluid is envisaged.

As indicate above, the tubes 1 arranged within the container 2 are fed with the fluid necessary by means of the feed-dispenser 4, which

,as can be seen in the figure comprises a duct 7 through which the fluid, for exmple Freon, is fed within the chamber 8 in wich there

are many short ducts 9 arranged in such a way that each of the ducts 9, thanks to its diameter being slightly less than that of the tube 1, is inserted into the corresponding tube 1.When .for the first time, the fluid to be fed into the tube 1 is fed into a chamber 8 through the duct 7, each of the tubes 1 is feed directly, thus avoiding the non uniformity of feed presented by the fed systems currently in use. Figure 7 shows a possible variant of the solution described, in wich all the feed ducts 9 are made to converge on a single manifold to which the inlet for the fluid to be fed into the tubes 1 is connected. Figure 8 shows a further variant of the feed device described , a set of nozzles obtained by pressing which, inserted into the tubes, allows them to be fed with the fluid.

In order to improve the circulation of the second fluid present within the casing 2. but outside the tubes 1, adjoining the delivery inlet for the fluid . wich may be for example water, a deflector 1 1 is envisaged that conveys the entering fluid directly onto the tubes 1 , imposing rigth from the start the route that the fluid must necessarily follows thanks to the diaphragms 12 present at interval along all the lenght of the tubes 1 as far as the outlet 6.

A further improvement of the circulation of the fluid within the tubes 1 has been obtained by arranging the tubes 1 in such a way ,as can be easily seen in figure 4, that the design of the cross section is

like a square or rectangle which, by means of the special bulkheads 13 arranged in parallel to the longitudinal axis of the heat exchanger by the side of the tubes 2. one obtains a restriction of the internal volume of the outer casing and a consequent increase of the pressure at which the fluid circulates within the tubes . at the same time preventing the creation of the dead areas not reached by the fluid or in which circulation of the fluid takes place very slowly or there is stagnation: again for the same motives just desccribed there is a further bulkhead 14 positioned at the final part of the tube 1 in correspondence with the internal part of the cover 3. The arrangement of the diaphgrams 12 and in particular of the passage of the tubes within them makes it possible to have a tube bundle free from the vibrations caused by the passage of the second fluid, vibrations that create a marked incrrease in noise and in the risk of rupture of the tubes with the passage of time. To what has far been described and illustrated there may be made all the modifications dictated by pratical application and by experts of the sector without leaving from the ambit of the invention as appears from the claims which follow.