Shut-off valve with incorporated expansion nozzle, for pressurised fluids of air cooling/heating apparatus

Abstract: Shut-off valve for pressurised fluids in particular for air cooling/heating apparatus comprising at least one condenser and at least one fluid evaporator to be placed in communication with each other by means of a pipe (15), wherein said valve comprises at least one duct (13; 113) which has arranged inside it a nozzle (20; 120) in which there is coaxially formed a capillary duct (26; 126) designed to cause rapid expansion of the fluid when it emerges from the nozzle, said nozzle being held in position by means (13e) for securing the said pipe (15) to the valve.

Description: The present invention relates to a shut-off valve for pressurised fluids of air cooling/heating apparatus such as conditioners and the like, wherein said valve comprises at least one duct which has arranged inside it a nozzle in which there is coaxially formed a capillary duct designed to cause rapid expansion of the fluid when it emerges from the nozzle, the pipe connecting the condenser and evaporator of the apparatus. It is known in the sector relating to the construction of air conditioners of the need to cause circulation of the ambient air through two heat exchangers which form respectively the condenser and the evaporator of the refrigerating cycle. It is also known that the condenser and the evaporator must be placed in communication with each another by means of shut-off valves and devices, such as for example thermostatic valves or capillaries designed to cause rapid expansion of the cooling fluid when the latter passes from one component to another. Said valves and expansion means are normally arranged inside the conditioner if the latter is of the conventional type with a single body; on the other hand, if the conditioner is of the type with a separate evaporator to be positioned inside the room, the valve is positioned outside and the expansion means inside the conditioner itself. More particularly, expansion may be performed upstream of the shut-off valve, i.e. in the condenser, or downstream of the shut-off valve, i.e. in the evaporator. Since the dimensioning of the means for expansion of the cooling fluid depends on the efficiency of the conditioner in relation to the different external temperatures, the technical problem which is posed is that of providing an expansion element which is accessible externally and easily interchangeable, in accordance with the variation in the said external temperatures at which the air conditioner is used and the length of the pipes thereof, without the need for complex welding operations. Within the scope of this technical problem, a further need is that said fluid expansion means should be associated with the valve for shutting off the said fluid during its travel path from/to the condenser/evaporator, thus making possible greater standardisation of the component parts with a reduction in the warehouses and transportation costs. From patent specification US-A-5 507 468 it is known to provide a nozzle within a duct, where the nozzle includes a capillary duct through which fluid passes and which is designed to cause rapid expansion of the fluid when it emerges from the nozzle, and where the end of the tube is outwardly flared and is held between a flare fitting nut and a conical end of a restrictor member. The nozzle, however, is spaced from the flared tube, and is otherwise moveable with respect thereto, and to the flare fitting nut. An object of the present invention is moreover that of providing a valve associated with fluid expansion means which may be used indifferently for operation of the apparatus in cooling cycles (air conditioners) or heating cycles (heat pumps). These results are achieved by the present invention, which envisages a shut-off valve for pressurised fluids in particular for air cooling/heating apparatus comprising at least one condenser and at least one fluid evaporator to be placed in communication by means of a pipe, wherein said valve comprises at least one duct which has arranged inside it a nozzle in which there is coaxially formed a capillary duct designed to cause rapid expansion of the fluid when the latter emerges from the nozzle, said nozzle being held in position by means for securing the said pipe to the valve. Further details may be obtained from the following description of an example of embodiment of the invention, provided with reference to the accompanying drawings in which: Figure 1 shows a partially sectioned exploded view of the valve according to the present invention with the single-acting expansion element incorporated; Figure 2 shows a partially sectioned view of the valve with the expansion element, in the assembled condition; Figure 3 shows a partially sectioned view of the valve according to the present invention with double-acting expansion means open for operation as an air conditioner; Figure 4 shows a cross-section along the plane indicated by IV-IV in Fig. 3; Figure 5 shows a partially sectioned view of the valve according to the present invention with double-acting expansion means open for operation as a heat pump; Figure 6 shows a partially sectioned view of a variation of an example of embodiment of the valve with double-acting expansion means. As shown in Figures 1 and 2, the valve 10 according to the invention is of the three-way type and substantially consists of a body 11 which has formed inside it three ducts, respectively: 12 for delivery of the fluid from the condenser, 13 for coupling to the pipe 15 (Fig. 2) for connection to the evaporator (not illustrated), and 16 for insertion of an instrument 16a (Fig. 2) for detecting and measuring the pressure of the liquid present inside the piping of the apparatus. The valve is completed by an obturator 18 which can be operated by means of a spanner acting on an adjusting nut 18a. The duct 13 is formed inside an outlet 13a with an external threading 13b; said outlet has inside it two coaxial seats, respectively 13c and 13d, for housing and receiving in abutment a filtering element 17 and a nozzle 20 retained in their seats by a nut 13e which can be tightened on the threading 13b of the outlet 13. The said nozzle 20 has an external surface formed with at least two conical surfaces 21 and 22 of opposite inclination, designed to ensure a seal respectively with the duct 13 of the valve body and the pipe 15 for connection to the evaporator. On the external surface of the nozzle 20 there is also formed an annular groove 23 for partially containing an annular sealing gasket 23a. The opposite front surfaces 24 and 25 of the nozzle have respective recessed seats 24a, 25a connected to one another by a capillary duct 26 coaxially formed inside the nozzle 20 and designed to cause the desired rapid expansion of the fluid prior to its transfer from the condenser to the evaporator. Although a preferred three-way embodiment has been described, it is obvious, however, that the valve according to the invention may be realized also with a two-way valve if it were not required to take the measurement of the pressure value of the liquid by means of the instrument 18. As illustrated in Figures 3, 4 and 5, the valve according to the invention may also be constructed with a double-acting expansion nozzle 120 for use in apparatus which functions both as an air conditioner and as a heat pump. In this case, in fact, it is required that expansion should occur in one direction or the other. In said embodiment it is envisaged that the outlet 113a should be elongated so as to form an internal duct 113 having a length such that it can contain two nozzles 120 which are identical to one another, but arranged opposite one another and movable in the axial direction along the duct 113 itself as will be specified more clearly below. Each nozzle, however, has an axial capillary duct with a different gauge depending on the different expansion which it must perform. More particularly, inside the duct 113 there is provided a seat 113c for the filter 17 and an additional seat 113d for housing a bush 127 which has coaxially inserted inside it the nozzle 120 which has a frustoconical anterior frontal surface 121 for effecting the seal against the corresponding seat and a rear part provided with radial fins 120a, at the rear end of which there is formed a projection 120b designed to come into contact with the rear end 127a of the bush 127 and with a spacer 128 inserted in the said duct 113 and provided with an annular depression 128a which allows a limited degree of axial sliding of the nozzle 120. As clearly illustrated in Figs. 3 and 5, the two nozzles 120 and the other parts are arranged so as to form a perfect mirror-image. Consequently, during operation as an air conditioner (Fig. 3) where expansion of the fluid must occur during flowing of the fluid from the valve 10 to the pipe 15, the pressure of the fluid itself produces sliding to the right of both the nozzles 120, thus causing opening of the aperture 113f defined between the nozzle 120 and the bush 127 of the right-hand nozzle and closing of the aperture 113g defined between the bush 127 and the left-hand nozzle 120. In this configuration, the fluid from the duct 12 of the valve 10 is able to flow freely until it encounters the left-hand nozzle where, in order to pass through it, it is necessarily channelled into the capillary 126 at the outlet of which the desired expansion occurs. Operation occurs in exactly the same manner, but in the opposite direction, during operation of the apparatus as a heat pump illustrated in Fig. 5, in which it is the right-hand nozzle which is open and the left-hand nozzle which is closed. Figure 6, finally, illustrates a variation of embodiment of the valve 10 with bidirectional expansion, in which the valve 10 has a configuration identical to that of Fig. 2 and is therefore not described further, while the second nozzle 120 is inserted inside the connector 30 fixed to the evaporator only schematically shown at 40. Said connector has a tubular section 33 with threading 33a, inside which the nozzle 120 is inserted as already described for Figs. 3 and 5. Finally the pipe 15 is inserted and is retained by the nut 34, causing the same operation described for Figs. 3 and 5 already mentioned, but with greater standardization of component parts. In this case, in fact, the valve 10 may be remain unvaried with respect to the single-acting configuration according to Fig. 2. Many variants may be introduced as regards the realization of the parts which make up the invention, without thereby departing from the protective scope of the present invention as defined by the claims which follow.

Claims: Shut-off valve for pressurised fluids in particular for air cooling/heating apparatus comprising at least one condenser and at least one fluid evaporator to be placed in communication with each other by means of a pipe (15), said valve comprising at least one duct (13; 113) which has arranged inside it a nozzle (20; 120) in which there is coaxially formed a capillary duct (26; 126) through which the fluid passes and which is designed to cause rapid expansion of the fluid when it emerges from the nozzle, characterized in that : said nozzle is held in position by means (13e) for securing the said pipe (15) to the valve, and said nozzle has two opposite inclined surfaces (21, 22), one surface (21) of which engages a corresponding surface (13c, 13d) of the duct (13, 113) so as to provide a seal preventing passage of the fluid, and the other surface (22) of which engages a flared end of the pipe, said means for securing being a flare-fitting nut (13e) threaded onto said valve. Valve according to claim 1, characterized in that on the body of the said nozzle (20) there is provided an annular seat (23) for housing an annular sealing element (23a). Valve according to claim 1, characterized in that said duct (13) has a seat (13c) for housing and receiving in abutment an element (17) for filtering the expansion fluid. Valve according to claim 1, characterized in that said valve is of the three-way type. Valve according to claim 1, characterized in that said valve is of the two-way type. Valve according to claim 1, characterized in that said duct (113) has elongated dimensions so as to contain two nozzles (120) located opposite one another for bidirectional expansion. Valve according to claim 6, characterized in that said elongated duct (113) has seats (113d) for housing respective bushes (127) inside which an associated nozzle (120) is coaxially inserted. Valve according to claim 6 or 7, characterized in that said first and second nozzles (120) have radial fins (120a) at the rear end of which there is provided a projection (120b). Valve according to claim 6, 7 or 8, characterized in that said nozzles (120) are coaxially slidable inside said duct (113). Valve according to claim 8 or 9 in combination with claim 8, characterized in that inside said duct (113) there is arranged a spacer (128) provided with an annular projection (128a) designed to come into contact with the said projections (120b) of the nozzles (120) so as to limit the axial travel thereof. Valve according to any one of claims 6 to 10, characterized in that said nozzles (120) have a coaxial internal duct of differing diameter with respect to one another. Valve according to claim 6, characterized in that said second nozzle (120) is inserted inside a connector (30) fixed to an evaporator (40) connected to the condenser by means of said pipe (15).

Inventors: CASIRAGHI DANIELE, CASIRAGHI, DANIELE
Applicants: PARKER HANNIFIN CORP, PARKER-HANNIFIN CORPORATION
Application year: 1997
Main classification: F25B41
IPC codes: F25B41