Improved automatic bleeding valve for hydraulic systems

Abstract: An improved automatic bleeding valve for hydraulic systems comprising: an outer body (1), a cover (5), a float (11) provided with an inclined surface (13) for acting onto the stem (15) of a valve head member (17), a spring (25) for pressing said member (17) against a toric gasket (23), a plug (27) for setting the manual or automatic operation mode of the valve; wherein the lower end (7) of the body (1) is provided with a calibrated hole (49) opening into a first air expansion chamber (51); wherein a bleeding spout (35) is equipped, upward of said opening (19), with an air expansion chamber (53), and with two facing recesses (55) for the air outlet, and wherein a sealing annular gasket (41) is provided, having a T shape, the stem (43) of which has a calibrated hole (45) for the same purpose.

Description: The present invention relates to an automatic bleeding valve for hydraulic systems such as hot-water heating systems by thermosiphon circulation and the like, particularly for large airflow systems. As it is known in hydraulic systems where a (usually hot) fluid circulates, for achieving an optimum operation of the system all traces of air are to be removed. A convenient and known way to achieve the above result is to install a bleeding valve, either manually or automatically operated, at the highest point of the system. The valves of this type comprise a floating member that rests into a seat and causes an automatic air discharge when the floating member is no longer in contact with the water. DE 2235161 discloses an automatic bleeding valve for hydraulic systems particularly for large air flow systems, comprising an outer body, a float movable inside said body and provided with a valve head member adapted to automatically open and close a bleeding opening when said float is respectively lowered or lifted, a cover fixed to said body with an interposed sealing gasket therebetween, said member being sealingly urged against a toric gasket by a spring, and a plug housed in the cover. FR 774492 discloses an air discharge device wherein the movements of a valve adapted to close a bleeding opening are controlled by an oscillating lever supporting at its both respective extremities two masses having different volumes and densities. FR 775296 describes an air discharge device of the type comprising a valve, the opening and the closure of said valve being provoked respectively by the lowering or by the lifting of the level of liquid inside a conduit, wherein the vertical movements of the valve are controlled by two counter-acting forces, one of which, obtained by means of a spring, remains constant, while the other force depends on the action of a weight. DE 2714118 describes a bleeding valve comprising a cylindrical housing and a float inside said housing, wherein the housing is mounted on a seat at the inside of which a plug valve is inserted. US 4,927,114 describes a tilt valve cartridge for a pneumatic mechanism which has a cylindrical housing having two open ends, an annular valve seat secured in one open end, a valve member in tiltable contact with the annular seat and having a valve stem which extends through the valve seat and protrudes from the end of the cylinder, a spring to hold the valve member in a normally closed relationship with the valve seat, a sealing element secured to the cylindrical housing on its exterior surface so as to seal the interface between the cartridge and the mechanism, and retention feature to capture the valve member and valve biasing spring within the cylindrical cartridge. However in systems with large flow rates and high pressures of the air to be ejected, the outcoming air jet directly strikes and lifts the float, thus closing the passage even when all the air has not been completely ejected and the float is in contact with water. The invention aims to solve the above mentioned problem and to provide an automatic valve of the float type that achieves the following advantages over the presently used valves: a reduced size; a correct operation with large air flow rates; a simple construction; a strongly limited cost; an improved reliability due to the absence of kinematic devices that might easily be blocked by the limestone present in hard waters at many locations. The novel characteristics of the bleeding valve according to the invention will become evident from the characterizing portion of the claims. The invention will now be disclosed with details with reference to the attached drawings, supplied only for exemplary and non limiting purposes, in which: Fig. 1 is a longitudinal cross sectional view of a device according to the invention in the automatic operation mode with the float in a lifted position (closed device); Fig. 2 is a longitudinal cross sectional view of a device according to the invention in the automatic operation mode with the float in a lowered position (open device); Fig. 3 is a longitudinal cross sectional view of a device according to the invention in the manual operating mode (closed device); Fig. 4 is a cross sectional view along line IV-IV of Fig. 3 illustrating the valve head and seat. As shown in the Figures, a bleeding valve according to the invention substantially comprises: an outer cylindrically shaped body 1, having a threaded upper end 3 for securing a circular cover 5 which is equipped with a radial bleeding spout 35, and a threaded lower end 7 for securing the body 1 to the system, a sealing gasket 9 being interposed between the cover 5 and the outer body 1. A float 11 is movable inside the body 1 and has an inclined surface 13 for acting onto a stem 15 of a valve head member 17 for automatically opening and closing a bleeding orifice or opening 19 in the cover when the float 11 is lowered or lifted respectively, the stem 15 terminating with an enlarged portion 21 for sealingly abutting against a toric gasket or "O ring" 23. A return spring 25, usually a conical spring, urges the member 17 against said toric gasket 23. A plug 27 is housed in said cover 5 and allows for the automatic operation of the bleeding valve when the plug is unscrewed, or sets the bleeding valve to the manual operation mode when it is screwed and occludes the opening 19. The sealing member or toric gasket 23 is common to both the automatic and the manual operating mode and such annular gasket is received in a groove 29 formed in the cover 5 and maintained therein without any dedicated fastening means. The end portion of the outlet opening is provided with an inwardly projecting caulked rim 33 to prevent the plug 27 from falling out of the cover after it has been loosened to enable the automatic operating mode. The plug 27 is flush in a seat of the bleeding spout 35, so that no component protrudes from the cover 5 besides the spout 35. The automatic system for closing and opening the valve is housed in the bleeding spout 35, whereby the full volume of the body 1 is free for housing the movable float 11. A plurality of fins 37 is provided on the bottom surface of the float 11 for better conveying the air towards the exhaust or bleeding opening. The lower end 7 of the body 1 is provided with a calibrated (gauged) hole 49 for air inlet and such hole opens into (communicates with) a first air expansion chamber 51. Upstream of the opening 19, in the bleeding spout 35 a second expansion chamber 53 is formed, with two facing recesses 55 in correspondence of the enlarged portion 21, these recesses assisting the air outlet, and with two facing guides 56 shaped like circle arcs, and acting as guide members for the head of the valve enlarged portion 21. Moreover downstream of said toric gasket 23, towards the closing plug 27, a sealing annular gasket 41 is positioned, having a cross section shaped like a horizontal T, the stem 43 of which has a calibrated hole 45 for allowing the air passage. The plug 27, when screwed for the manual closure, abuts against the head 47 of the sealing gasket 41 downstream of the toric gasket (O ring) 23. Numeral reference 57 indicates two notches formed in the head of plug 27, through which the air escapes from the valve when the plug is open, both in the automatic and manual operating mode.

Claims: An automatic bleeding valve for hydraulic systems particularly for large air flow systems, substantially comprising: an outer body (1) having an uppe (3) and a lower threaded end (7), said body being securable to said system through said lower threaded end (7); a float (11) movable inside said body (1) and provided with an inclined surface (13) for acting onto a stem (15) of a valve head member (17) adapted to automatically open and close a bleeding opening (19), when said float (11) is lowered or lifted, respectively; a cover (5) fixed to said body through said upper threaded end (3) with an interposed sealing gasket (9) therebetween, said member (17) being sealingly urged against a toric gasket (23) by a spring (25); a plug (27) housed in said cover (5) for allowing an automatic operating of said bleeding valve when the plug is unscrewed, and the manual operation of the bleeding valve when the plug is screwed, characterized in that - upstream of said bleeding opening (19) - a bleeding spout (35) is provided with an air expansion chamber (53), and in correspondence of an enlarged portion (21) of said valve member (17), said bleeding spout (35) is provided with two facing recesses (55) assisting the air outlet and with two facing guides (56) shaped like arcs of circles and acting as guides for said enlarged portion (21) of the valve head member. An automatic bleeding valve for hydraulic systems according to claim 1 characterized in that the lower end (7) of said body (1) is provided with a calibrated hole (49) for air inlet that communicates with a further air expansion chamber (51). An automatic bleeding valve for hydraulic systems as claimed in claims 1 and/or 2, characterized in that downstream of said toric gasket (23), towards said closing plug (27), a sealing annular gasket (41) is disposed having a cross section shaped like a horizontal T, the stem (43) of said toric gasket (23) has a calibrated hole (45) for allowing the air passage, and said closing plug (27) - when screwed for the manual closure - abuts against the head (47) of said sealing gasket (41) downstream of said toric gasket (23). An automatic bleeding valve as claimed in claim 3, characterized in that said toric gasket (23) is received in a groove (29) of the cover (5) and maintained therein without any dedicated fastening means. An automatic bleeding valve as claimed in claim 3, characterized in that the end of said bleeding spout is provided with an inwardly projecting rim (33) that is caulked to prevent said plug (27) from coming out of said spout after said plug has been loosened for the automatic operation of the valve. An automatic bleeding valve as claimed in claim 3, characterized in that a plurality of fins (37) are provided on the bottom surface of said float (11) for better conveying the air towards the bleeding opening. An automatic bleeding valve as claimed in claim 3, characterized in that said sealing gasket (41) is inserted or screwed in a suitable seat. An automatic bleeding valve as claimed in claim 3, characterized in that upstream of the recess housing said toric gaske (23) there is provided said air expansion chamber (53) provided in the bleeding spout (35). An automatic bleeding valve as claimed in claim 7, characterized in that said sealing member (23) is a rubber gasket of toric or flat configuration. An automatic bleeding valve as claimed in any claims 4 to 8, characterized in that the groove (29) in which said sealing member (23) is inserted has a different shape from a toric or flat shape, e.g. a "dovetail" shape, for an improved retaining of said sealing member under high pressure conditions.

Inventors: FERRERO RICCARDO, FERRERO, RICCARDO
Applicants: FAMFERS N C DI RICCARDO FERRER, FAMFERS.N.C. DI RICCARDO FERRERO & C.
Application year: 1999
Main classification: F16K24
IPC codes: F24D19, F16K24