Patent Application
20240210969
The present invention relates to a compact field calibratable pressure reducing valve. More particularly, the present invention relates to a novel pressure regulating valve of the Pressure Reducing Valve type, of compact size and field calibratable, i.e. when arranged in place, typically but not limitedly for use in fire-fighting systems.
Hydraulic water pressure reducing valves or devices are widely known and used, particularly in the fire-fighting protection systems sector, constructively they are straight globe and angle valves (as per NFPA14 standard), provided with means of manual field adjustment of the downstream pressure, either as dynamic pressure in the presence of flow or residual pressure or static pressure in the absence of flow.
These well-known types of valves are advantageously used in fire-fighting systems because they allow the water pressure to the connecting hoses of hydrants or other fire extinguishing systems, such as sprinklers, to be kept under control regardless of the static or residual pressure of the upstream supply.
For example, in a traditional fixed fire-fighting system in a multi-storey building, both the static and residual pressure of the supply arriving at the fire-fighting connection boxes on each floor will gradually decrease as the height or pressure head at which the floor of the building is located increases. The static and residual operating pressures of the system on the lower floors will therefore always be higher than the operating pressures on the upper floors.
The residual pressure adjustment at the valve outlet can be pre-set, allowing the valve to maintain constant outlet pressures as the elevation of the utilization changes in such a way to ensure that the correct required pressure is provided to each floor.
Pressure Reducing Valves also have the task of limiting downstream pressure even under non-flow and static pressure conditions, typically below 12 bar. This pressure control occurs through a pressure-controlled chamber inside the valve, otherwise the pressure reduction is not adjustable, but defined by the valve geometry itself.
Manual residual pressure adjustment can be instead performed directly on field, by means of tools or wrenches, depending on the available upstream pressure of the valve itself. These types of valves are generally classified according to how the pressure is adjusted and whether or not such adjustment is possible on field once installation.
In order to control the static and dynamic water pressures prescribed by design, these well-known types of fire valves are provided with elastic counter elements typically consisting of preloaded coil springs coaxially arranged to the plug stem.
The spring is preloaded in such a way that even when the valve is opened by acting on the handwheel or knob, the valve plug will remain closed until the outlet water pressure has reached a value equal to or less than the force required to overcome the spring resistance and lift the valve plug to open.
The reduction valves described above are specific valves for applications on fire-fighting systems that operate with very high flow rates and hydraulic fluid pressures, generally about an order of magnitude higher than the classic balancing valves used in other thermal field applications, said fluid flow rates typically about of 500 gpm (gallons per minute) equivalent to about 113 m3/h (cubic meters per hour) with inlet pressures about of 500 psi (pounds per square inch) equivalent to about 34 bar. However, the safety factor required for certifications of these valves by UL/FM certifying authorities is 5 times, or about 170 bar. A typical example of these types of pressure regulating valves are the well-known pressure reducing valves type, calibratable on field, manufactured by the Applicant in the series named A201, A202, A203, A204 (see Giacomini S.p.A. Product Catalogue, web address: https://www.giacomini.com/en/products/hose-sprinkler-valves-and-accessories).
However, these types of field calibratable Pressure Reducing Valves have some operational limits.
A typical limitation of these well-known types of valves particularly perceived in fire-fighting systems, is that the coil springs have considerably large dimension relative to the valve body, especially in length, and such as to allows the valve itself to operate at high pressure ranges, typical of fire-fighting systems. The distance between spring coils also must be such as to ensure that the spring can be preloaded over in a range of variable forces necessary to counteract the variable pressure of the water, thus necessarily making the coil spring bulky in length.
This limitation implies that field calibratable fire-fighting pressure reducing valves necessarily have large constructive overall dimensions, especially in the height dimension, in order to accommodate the coil springs, overall dimensions such that make valve installation in a traditional fire-fighting box difficult if not impossible.
The problem of how to reduce the overall dimensions of these well-known types of valves is particularly required in the state of the art.
A further limitation of these well-known types of valves is due to the fact that they are not easily adjustable at high flow rates and high outlet pressures as shown by diagrams in
A solution aimed to limiting overall height dimensions is described in U.S. Pat. No. 7,320,333 (B2) referring to a field adjustable pressure reducing valve, suitable for connection to a water supply line, which includes a valve body with an inlet for connection to the pressurized water supply line, an outlet, a passage extending between the inlet and outlet and a valve seat. A valve stem provided with a sealing element is disposed in said passageway. An automatic pressure reduction system is provided to push the sealing element toward the valve seat so as to close the passageway to reduce pressure to the outlet. The automatic pressure reducing system includes helical springs arranged in parallel in such a way as to occupy less space for a given spring load than conventional springs.
A further limitation of these well-known types of valves is also due to the fact that it is not possible to easily vary the spring stiffness by varying the working range of the valve, creating new models or developing existing models, without necessarily varying characteristics and dimensions of the compression coil springs.
However, the technical solution in U.S. Pat. No. 7,320,333 (B2), while providing more compact dimensions, does not confer advantages in terms of pressure regulation.
It is scope of the present invention to overcome and obviate, at least in part, the above-mentioned drawbacks and operational limitations.
More particularly, it is scope of the present invention to provide a field calibratable pressure reducing valve, i.e., once arranged in place, small and compact in size compared to known art valves and such that it can be easily operated and calibrated/adjusted by the user once installed inside a conventional fire-fighting box in very limited space.
A further scope of the present invention is to provide a compact field calibratable pressure reducing valve capable of being manufactured in modular families or series such that it can be operate over different pressure ranges while maintaining the same external overall dimensions of the valve, or of its adjusting portion, even in valve models suitable for operating over higher pressure ranges without having to increase proportionately its overall dimensions.
Not least scope of the present invention is to provide a compact field calibratable pressure reducing valve with improved control capability at high flow rates and high outlet pressures. Further scope still of the present invention is to provide a compact, field calibratable pressure reducing valve capable of a high level of mechanic strength and reliability over time, such that it can be easily and economically manufactured.
These and other scope are achieved by the compact field calibratable pressure reducing valve of the present invention in accordance with the independent claim.
The constructional and functional features of the compact field calibratable pressure reducing valve may be better understood from the detailed description below, in which reference is made to the attached drawings representing some preferred and non-limiting embodiments in which:
With reference to figures and in particular
The compact field calibratable pressure reducing valve 10 includes:
Said valve 10 has the novel feature of an elastic compression member 32 comprising a plurality of disc springs 36, 36′ also known as conical washer springs or Belleville springs, said disc springs 36, 36′ being axially arranged in a stack on said second stem portion 23 between said piston 26 and said adjustment ferrule 34.
Said plug 24 is slidingly disposed in axial direction in said body 11 integral with the first stem portion 22 placed in connection with piston 26 and said second stem portion 23 slidingly rotatable and operable by a handwheel 50 by means of a threaded coupling with a bell 18 fixed to body 11 of valve 10.
Said plurality of disc springs 36, 36′ have a traditional concave discoidal washer shape with a truncated cone development where each disc spring is configured to be elastically loaded in the axial direction. With reference still to the preferred embodiment form of
Said elastic compression member 32 comprising a plurality of disc springs 36, 36′ may also advantageously be defined by stacking each or groups of disc springs 36, 36′ with concavity in a concordant or opposite direction so as to obtain an elastic characteristic analogous to a conventional coiled compression spring or obtain an ideal design characteristic for the valve type and pressure ranges of valve operation.
Said elastic compression member 32 may also advantageously comprise two or more packs or stacks of disc springs arranged in series, said packs or stacks being formed of a first type of disc spring 36 and a second type of disc spring 36′ having different geometric and elastic characteristics.
A different stacking arrangement of the disc springs 36, 36′ allows the compression spring member 32 to absorb high compressive loads in a reduced housing space and bulk in both axial and radial directions compared to a conventional coiled compression spring.
A different configuration of the disc spring arrangement 36, 36′ allows the compression spring member 32 to achieve characteristic load and stroke curves of both linear and digressive or progressive types. By arranging said plurality of disc springs 36, 36′ or two or more stacked groups of them in series, arranged with alternating opposite concavity of the discs in the axial direction, as in the preferred embodiment of
With particular reference to the diagrams of
By varying for each group or stack of disc springs 36, 36′ the number or geometric characteristic of the discs, diameter and thickness, as well as the direction of stacking, variable stiffness values can be obtained depending on the compression.
Disc springs 36, 36′ also have further additional advantageous features compared to conventional coiled compression springs such as a low tendency to plastic deformation and elastic relaxation and a concentrically distributed load compared whit a coiled compression spring.
With special reference to
Said disc springs 36, 36′ are generally made of steel but can also be made of other materials having similar elasticity and strength.
Said valve body 11 and bell 18 are typically made of brass alloys for hydraulic use but may also be made of any oxidation resistant metal or polymeric plastic materials.
In the embodiment of the figures, given for illustrative and non-limiting purposes only, the inlet opening 12 is arranged at an angle of 90° with respect to the outlet opening 14, however in further possible alternative embodiments the inlet and outlet openings may also be arranged on the same axis at an angle of 180° or in intermediate positions.
Said hydraulic connection means 15 may be conventional male or female threads formed on the valve body at said inlet and outlet openings 12, 14 or other known types of male or female hydraulic connections such as fast couplings, fittings or equivalents.
Said disc springs 36, 36′ may also have in further variant embodiments, in addition to different thicknesses and diameters, shapes and profiles typical of known washers such as, for example, wave washer, tooth washer etc., having different mechanical behaviours.
Still, in the preferred embodiment of the figures, said shutter assembly with piston 26 and elastic compression member 32 can be slidingly arranged directly in body 11 of valve 10 or inside a lantern sleeve 40 defining a detachable cartridge assembly with respect to body 11 of valve 10.
In the preferred embodiment of the figures, the shutter assembly 20 is further configured to close the passage of water by translating in the direction opposite to the direction of passage of water from the inlet opening 12 to the outlet opening 14 but, in a variant embodiment, may be configured to close the passage of water by translating in the same direction as the passage of water.
From the description of the compact field calibratable pressure reducing valve 10 of the present invention, its operation described below is evident.
With reference to the figures and in particular
Referring only to
Said rod 52 is screwed into the conjugate thread of said bell 18 transmitting axial motion to said second stem portion 23 only when rod 52 moves by screwing upwardly (as in the configuration of
The upward axial movement of the second stem portion 23 in an axial direction leads the piston 26 and the second stem portion 22 upward, leading the shutter assembly 20 with the shutter 24 to close the passage within the chamber 16 of the body 11 by connecting the inlet opening 12 with the outlet opening 14 in a fluid connection.
When, on the other hand, the rod 52 is screwed sliding downwardly, the shutter assembly 20 with the first stem portion 22, the piston 26 and the second stem portion 23, connected together, can float freely translating in the axial direction, in such a way that the opening or closing of the shutter assembly 20 is not controlled by the position of the handwheel 50 but by the balance between the pressure force of the outgoing water (acting on a portion of the piston) and the elastic force of the compression of the spring member 32 with the disc springs 36, 36′.
The water pressure at the outlet opening 14, arriving through a passage 19 formed in the body 11, applies a pressure force on the exposed surface of the piston 26 counteracted by the force from the elastic compression member 32.
When the water pressure reaches a value such as to overcome the force of the elastic compression member 32, the piston 26, together with the shutter assembly 20, translates to close the passage of water between the inlet opening 12 and the outlet opening 14.
Reducing the water passage cross-section through the same half-closed shutter assembly 20 results in an additional pressure drop, i.e., a reduction in water pressure at the outlet opening 14 outlet, thereby allowing the piston 26 and the shutter assembly 20 to converge to a balance position.
The resistance of the elastic member 32 to the water pressure at the outlet opening 14 can be increased by loading and unloading the elastic compression member acting on the piston 26 in a direction opposite to the pressure force, by operating on the compression assembly 30 by screwing and unscrewing the adjustment ferrule 34 which slides in an axial direction with respect to the second stem portion 23 by compressing or decompressing the disc springs 36, 36′ of the elastic compression member 32.
Said adjustment ferrule 34 is typically provided with a plurality of holes or openings on its exposed surface suitable for housing a rod (not shown) in order to apply the rotational torque for adjustment. Said adjustment may be performed with any other type of tool or wrench acting on a conjugate profile formed on the outer surface of said adjustment ferrule 34 such as a conventional hexagon wrench.
With reference to the figures, the valve 10 can also be provided with a striker element 70 having a socket shape and capable of axially translating in solidarity with the handwheel 50 and the rod 52, said striker element 70 being capable of looking at reference means (not shown), which can be stamped or shown on the same striker element 70 or, in alternative forms on the bell 18 or other elements, in such a way as to visually indicate to the user the operating status of the valve, open or closed.
With reference still to the same figures and in particular to
With special reference again to
Said adjustment ferrule 34 of the compression assembly 30 may also advantageously be protected by a safety cover (not shown) to prevent tampering with the adjustment of the elastic compression member 32.
In the preferred embodiment of the valve 10 shown in the figures, the closing of the shutter 24 of the shutter assembly 20 is accomplished by a translation in a direction opposite to the direction of passage of water from the inlet opening 12 to the outlet opening 14.
The described invention however, in an alternative variant embodiment, may function mutatis mutandis in the same way in the opposite configuration, wherein the closure of the shutter of the shutter assembly occurs with a translation in a direction concordant with the direction of passage of water from the inlet opening 12 towards the outlet opening 14.
However, the first preferred embodiment configuration is further advantageous since the inlet pressure acts simultaneously and oppositely on the top face of the shutter 20 and on the exposed surface of the piston 26, making the closing mechanism of the shutter assembly less sensitive to said inlet pressure, i.e. more dependent on the outlet pressure alone which determines the operation of the valve 10.
As can be seen from the foregoing, the advantages that the compact field calibratable pressure reducing valve of the present invention achieves are obvious.
The compact field calibratable pressure reducing valve 10 of the present invention is particularly advantageous because it allows to provide the user with a device of sensibly reduced overall dimensions with respect to the known art, as from the comparison of
A further advantage of the compact field calibratable pressure reducing valve 10 of the present invention is that it is possible to stack disc springs 36, 36′ differently in order to change the spring constant stiffness or stroke of the stack of disc springs obtaining an overall stiffness constant analogous to a corresponding equivalent spring or to a plurality of spiral springs concentrically arranged in parallel, for example by stacking some disc springs 36 in a concordant direction thus obtaining a reduced bulk of the compression spring member 32 and consequently of the valve also in the direction radial to the axis of the same compression spring element.
A further advantage of the compact, field calibratable pressure reducing valve 10 is that it is also possible to use disc springs 36, 36′ of different thicknesses and shapes in order to have a wide range of modularity and to achieve any value of elastic constant or stiffness of the elastic compression member 32, in such a way as to be able to obtain values of stiffness and resulting spring rate that can be designed specifically for the type of use, being able to obtain an infinite number of values of the elastic constant or spring rate with a reduced valve space 10.
Although the invention has been described above with particular reference to a preferred embodiment, given for illustrative and non-limiting purposes, numerous modifications and variations will become obvious to a skilled person in the light of the above description. The present invention, therefore, is intended to encompass all modifications and variations falling within the scope of protection of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000010403 | Apr 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/053766 | 11/5/2021 | WO |
