IMPROVED EVAPORATOR FOR COOLANT FLUIDS

Abstract: An evaporator for coolant fluids comprises two tabular elements of different diameter that are inserted coaxially one into the other so as to form a circumferential space within which coolant fluid can circulate. The said space is subdivided into a plurality of adjacent annular chambers by means of a series of annular baffles force-fitted in a sealing manner between the said two tubular elements. The said annular chambers intercommunicate by means of at least a bore made in each of the said baffles, the bore of one baffle being made diametrically opposite the bore in the adjacent baffle. At the opposed ends of the evaporator provision is also made for an inlet duct and for an outlet duct for the coolant fluid.

Description: The present invention relates to an improved evaporator for coolants, particularly but not exclusively adapted for use in foodstuff pasteurizers and devices for whisking icecream, especially for producing so-called soft icecream. Evaporators are known in which the coolant is passed through a hollow space formed between the walls of two tubular elements of different diameter inserted one into the other. In embodying evaporators of such type the problem requiring solution is minimization of coolant pressure drops and at the same time assurance that the coolant itself laps the entire heat-exchange surface in an even manner. It is known to solve this problem by means of a labyrinthine path for the coolant, by threading the outer tube internally, which is however a somewhat costly process and the depth of the threading is limited so that the evaporator is suitable only in the case of relatively high temperatures because of the low coolant flow rate. Another evaporator of the prior art is for instance described and shown in GB-A-720 921. This evaporator comprises two tubular elements of different diameter coaxially inserted one into the other, so as to form a circumferential space for coolant circulation. The said space is subdivided into a plurality of adjacent annular chambers by means of a series of annular baffles force-fitted in a sealing manner between the said two tubular elements. The said annular chambers intercommunicate by means of bores through each of the said baffles, the bore of one baffle being in a position diametrically opposite the bore of an adjacent baffle: provision also being made of the opposite ends of the evaporator for a coolant inlet duct and a coolant outlet duct. The overall object of the present invention is to satisfactorily resolve the aforesaid technical problem by embodying an evaporator which, though very economical to manufacture, features a labyrinthine circuit by means of which the coolant can evenly lap the entire heat exchange surface with minimal pressure drop. The said object is attained by embodying an evaporator as defined in claim 1. The structural and functional characteristics of the invention, and its advantages over the known art, will become more apparent from an examination of the following description, referred to the appended drawings which show an example of an evaporator embodied according to the innovative principles of the invention. In the drawings: Figure 1 is a cutaway perspective and sectioned view illustrating an evaporator embodied according to the invention; Figure 2 is a longitudinal section of the evaporator of Figure 1; and Figure 3 is a view of an enlarged particular. With reference to the drawings, the evaporator in question is indicated overall by 10 and consists structurally of two tubular elements 11, 12 of different diameter, internal and external respectively, which are inserted one into the other so as to form between them a space for coolant circulation. The elements 11, 12 are fixed to each other by terminal flanges 13, 14 welded onto them. In accordance with the invention, the space formed between the two tubular elements is subdivided into a plurality of circumferential chambers 15 by means of a series of adjacent annular baffles 16. The chambers 15 intercommunicate by means of sets of bores 17 in the baffles 16; as Figure 1 and 2 clearly show, the bores 17 of adjacent baffles 16 are diametrically opposed. More specifically,with particular reference to Figure 3, each baffle 16 features a circumferential edge, in the form of a claw 18, and a collar 19 having a conical portion 20. The baffles 16 can in this way be force-fitted, through the agency of the claw 18, onto the internal tubular element 11, the conical portions 20 of the baffles 16 surmounting the collar 19 of the adjacent baffles 16. The external tubular element 12 is then force-fitted onto the said portions 20. Alternatively, the conical portion 20 can be welded to the collar 19. The numerals 21 and 22 indicate, respectively, a coolant inlet duct and a coolant outlet duct at the opposite ends of the evaporator; the path followed by the coolant within the evaporator is indicated in Figure 1 by arrows. It will in this connection be seen that the coolant leaving the alternate bores divides in two opposed directions, using the same channel, until reaching the successive bores, and so on. In this way there is a double passage section and an evaporator length divided in half, with the resulting advantage of an equal service pressure and thus an equal distribution of coolant along the evaporator. It will also be seen that the evaporator according to the invention is extremely economical to manufacture, since it requires simply the making of the baffles 16, which can be sheared and drawn.

Claims: Evaporator for coolant fluids of the type comprising two tubular elements of different diameter (11,12) coaxially inserted one into the other so as to form a circumferential space for coolant circulation, wherein the said space is subdivided into a plurality of adjacent annular chambers (15) by means of a series of annular baffles (16), the said annular chambers (15) intercommunicating by means of at least a bore (17) through each of the said baffles (16), the bore (17) of one baffle (16) being in a position diametrically opposite the bore (17) of an adjacent baffle (16), provision also being made at the opposite ends of the evaporator for a coolant inlet duct (21) and a coolant outlet duct (22), characterised in that each of the said annular baffles (16) features a clawed circumferential edge (18) which is pressure-fitted onto the internal tube (11), and a collar (19) having a conical portion (20) adapted to couple to the collar (19) of the adjacent baffle (16), the external tubular element (12) being pressure-fitted onto the said conical portion (20). Evaporator as described in claim 1, characterised in that the said conical portion (20) is welded to the said collar (19).

Inventors: BRAVO, FRANCESCO
Applicants: BRAVO S.P.A.
Application year: 1988
Main classification: A23L3
IPC codes: A23G9, F28D7, A23L3, F25B39, B01D1, F28F9