The present invention refers to a valve device and a method for making internal protrusions into a metal tubular body of a valve device, to retain a ball shaped valving member in an axial direction of the valve device, for example in check valves, or valve devices of any type, suitable for being arranged in ducts, pumping units, in order to retain the ball member, preventing the same from being entrained by the flowing fluid in an open condition of the valve device; the invention refers also to a check valve device of ball type comprising a tubular body provided with internal protrusions to axially retain a movable ball member, and its use in pumping units and in fluid circulation ducts.
In a plurality of applications, for example in food, chemical and/or naval fields, use is made of check valves of ball type, enabling a fluid to flow in a prefixed direction, preventing the fluid from flowing backwards in a direction opposite to the previous one.
In general, a ball check valve comprises a valve body defining a flow path between an inlet and an outlet side for a fluid, in which a ball-shaped closure member is provided to axially move between a closed position against a sealing seat and an open position against internal retaining members or shoulder surfaces.
Ball check valves of the above mentioned type are known for example from GB 2287085, DE 102005012298 and JP 58124873.
In a plurality of technical fields in which use of check valves is made, a problem exists to prevent residues of fluid material from remaining on internal surfaces of the valve, or deposition at dead points, or undercuts, that could be cause of contamination.
In this regards, the roughness of the internal surface of the valve body, may also imply sometime a problem; furthermore, since the closure ball member of the valve device must be retained at the outlet side for the fluid, by providing proper retaining elements, for example internal protrusions by casting or machining the interior of the valve body, as disclosed for example in JP 58124873, GB 2287085 and DE 102005012298, some standards currently in force establish that the internal surface of a valve body exhibits adequately wide curvature radii, such to prevent deposition and residues of the flowing fluid from being formed inside the same valve device.
In pumping thick fluids, dual diaphragm pumps are frequently used provided with a system of ball check valves arranged and oriented for controlling the suction and delivery of the fluid, alternatively from branched out ducts of the same pump. In the case of pumping systems of this type, the pump assembly and the whole check valve system further require to be easily cleaned, in order to remove any possible residues of contaminated product without having to remove the pump assembly from a plant, or without having to dismount the entire check valves. Dual diaphragm pumps provided with a ball check valve system are shown for example in DE 102005012298 and U.S. Pat. No. 6,651,693.
In still other applications, a need may exist to dispose of a ball valve device conformed for enabling a controlled flow of a fluid along a duct, or through discharge openings, by preventing solid particles entrained by the fluid from passing through.
A main object of the present invention is to provide a method for making a retainer or stops for a ball member in a valve device suitable for conveying and/or circulation of a fluid, by a very simplified solution of relatively reduced cost.
A further object of the invention is to provide a ball valve device, such as a ball check valve, conformed with internal ball retaining members that are free from sharp edges and/or undercuts to prevent the formation deposition of residual material and contamination of the flowing fluid.
A still further object is to provide a pump unit, for example a pump of dual diaphragm type, provided with ball check valves according to the invention, as well as to provide alternative solutions in manufacturing ball check valves of conventional type.
According to the invention, a method has been provided for making a retainer for a ball member in a metal tubular body of a valve device, wherein a cylindrical wall of the tubular body is provided with one or more cup-shaped internal protrusions, suitable for preventing the ball member to be entrained by a flowing fluid, wherein the cup-shaped internal protrusions are formed by radially pressing and inwardly deforming the peripheral wall of the tubular body, at one or more deformable areas angularly spaced apart along an annular band.
According to another aspect of the invention a tubular body for a ball type valve device has been provided, in which the valve body is conformed with cup-shaped internal protrusions for retaining a ball member, according to the method of claim 1, as well as a check valve of the ball type according to claim 4, and a pumping unit comprising one or more ball check valves according to claim 8.
These and further features of the present invention, as well as some examples will be better apparent from the following description, with reference to the drawings, in which:
With reference to the
In
The protrusions 13A may be conformed anyway by radially pressing and deforming the cylindrical wall 11 of the tubular body 10, according to specific requirements of use; in the case of
The radial deformation of the areas 13 for the protrusions 13A along a peripheral band 12 of the cylindrical wall 11 of the valve body can be carried out in any suitable manner, by using any pressing device conformed for causing a radial deformation inwards the wall 11 of the valve device. In the example of
The thrust member 17 rearwardly extends with a stem 18, to apply the force F, which stem 18 can be manually actuated for example by a screw device, not shown, or by a hydraulic or pneumatic actuator, or actuator of any other suitable type. Preferably, three tubular guides 16 are mechanically connected to each other, as shown by 19, so that the resultant of the three forces F oriented towards the longitudinal axis of the tubular body 10 is substantially null; consequently, a central symmetry deformation is obtained for the internal protrusions 13A.
In
In order to prevent that one or both ends of the tubular body 10 become oval, or lose their circular shape during press-forming of the cup-shaped protrusions 13A, according to another aspect of the invention, after the band 12 and the deformable regions 13 of the wall 11 have been defined, a cylindrical counteracting plug member 20 is fitted into one or both ends of the tubular body 10,
Thus, according to the invention, after having determined the positions of the annular band 12 and the deformable areas 13, as well threading of the counteracting plug member 20, if necessary, into one or both ends of the tubular body 10, the tubular body 10 is positioned within the press-deforming device; radial forces F are progressively applied to the deformable areas 13 to cause the internal cup-shaped protrusions 13A to be formed with the desired shape and dimensions; the possible presence of the internal counteracting plug member 20, prevents the corresponding end of the tubular body 10 from become oval or deformed.
When the radial deformation of the wall 11 has ended, the tubular body 10 with the so formed internal protrusions 13A, can be removed by loosening the forces F, in order to successively subject said tubular body to other mechanical operations, for example for forming end joining portions of a valve body as described in the following, with reference to
In
The cylindrical wall 11 of the valve body, at each end thereof, is conformed or provided with a joint or connection element 26, 27 of any suitable type, for example consisting of a thread joint or an annular flange, as shown, for allowing a sealing connection, for example by a clamp 28, with a flange 29 of a connection piece to a duct 31A, in which the flange 29 is provided with a conical sealing seat 30 for the closure ball member 14, respectively with corresponding flange 29 for a connection piece to a duct 31B for the circulation of a fluid, or for connection to any hydraulic apparatus.
The
The example of
In both cases, the resulting valve device is suitable for operating in a vertical disposition in order to enable the ball member 14 to fall down under its own weight when an upstream pressure, or a downstream vacuum pressure is missing, or when the entraining effect of the fluid circulating through said valve device is missing. However, other applications and/or arrangements of the valve device are possible, by orienting said valve device in any slanted or horizontal condition, use being provided, in this case, of a counteracting spring, not shown.
Lastly, by way of example,
The dual diaphragm pump unit, indicated as a whole by reference number 35, comprises a central body 36 and two lateral bodies 37, each lateral body 37 defining a pumping chamber 38 closed by a flexible membrane 39 of circular shape. A linear actuator 40 of double-acting type, with relative slide valves for switching the fluid under pressure in order to control the reciprocating movement of the pump, is positioned in the central body 36. As shown, the pump unit 35 comprises, both at intake and delivery sides of the two pumping chambers 38, a ball check valve 25 of the type previously described with reference to
The combination of a pumping unit, in particular the dual diaphragm pump 35, with ball check valves according to the invention, results very advantageous since enables the entire pump unit to be rapidly installed and/or removed, as well as the pump unit and the same valves to be easy cleaned, by simply acting on the tightening clamps 28.
Consequently, the shown solution results very advantageous owing to the following reasons:
it enables the ball-retaining cup-shaped members 13A to be obtained by a simple mechanical deformation of the body of a tubular element 10, preventing thus the use of additional retaining elements;
it enables the retaining members 13A to be conformed with a required hemispherical or cup shape the internal surface of the tubular body 10 by gradual curvature radii, suitable for preventing sharp edges or undercut portions, i.e. such to remove or substantially reduce any risk of deposition of encrustation of the product or conveyed fluid;
it eventually enables different types of valve device to be designed, suitable for any application.
Consequently, all was said and shown in the enclosed drawings is intended to have been given by way of example only, and other modifications or variations can be produced without thereby departing from the enclosed claims.
Number | Date | Country | Kind |
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M12010A000974 | May 2010 | IT | national |