WO2023089364A1

WO2023089364A1 - A retrofittable valve for a hydro-pneumatic accumulator

Info

Publication number: WO2023089364A1
Application number: PCT/IB2021/060730
Authority: WO
Inventors: Jimmi WENDERBY
Original assignee: Dellner Hydratech Group
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2023-05-25

Abstract

Present disclosure discloses a retrofittable valve (7) for a hydro-pneumatic accumulator (50). The retrofittable valve includes a body (7a) defining a first cavity (8a) extending from a distal end (D), where the first cavity is structured to removably accommodate at least a portion of a pre-existing valve (5) of an accumulator. The body defines a second cavity (8b) extending from a proximal end (P) of the body, and a passage interconnecting the first cavity and the second cavity. Further, the retrofittable valve includes an end port (9) defined in the second cavity and having an inlet (9a), and a valve member (10b) movably positioned in the passage. The valve member is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet of the end port and a port of the pre-existing valve of the accumulator.

Description

“A RETROFITTABLE VALVE FOR A HYDRO-PNEUMATIC ACCUMULATOR”

TECHNICAL FIELD

[001] Present disclosure generally relates to the field of hydraulics and pneumatics. Particularly, but not exclusively, the present disclosure relates to a hydro-pneumatic accumulator. Further, embodiments of the present disclosure disclose a retrofittable valve for concealing a pre-existing valve of a hydro-pneumatic accumulator employed in a system, such as, but not limited to a wind turbine pitch actuation system.

BACKGROUND

[002] An accumulator is an energy reservoir that accumulates and delivers fluid power when required by the fluidic circuit or system. The accumulator can be of hydraulic or pneumatic type, or a combination of both, and may make use of a spring, a raised weight, or a compressed gas to accumulate and deliver energy during use. Apart from functioning as energy reservoirs, accumulators are also designed to smooth out surges or pulsations in the working fluid. Thus, accumulators play a vital role in optimizing operating efficiency of the fluid system apart from ensuring smooth, reliable operation of the system in which they are installed. Out of weight loaded, spring loaded and compressed gas type accumulators, compressed gas type is a popular choice owing to quick responsiveness to power demand in comparison to weight and spring- loaded counterparts. Accumulators find a wide range of applications including, but not limited to Agricultural machinery, Automotive, Construction equipment/machines, Utility vehicles, and sophisticated industrial areas such as aerospace industry, Power plant industry, Shipping/Marine systems, Chemical industries and so on. Wind Turbine sector is one of the areas which finds extensive utility of accumulators to optimize pitch regulation of blades.

[003] Wind Turbine is a prime mover which converts power in the wind into electricity. The conversion essentially involves utilizing aerodynamic lift forces to produce a net positive torque on a rotating shaft, resulting first in generation of mechanical power, and then its transformation into electricity through a generator. Wind turbine blades have airfoil profiles that are best suited to generate lift forces. The blades are typically attached to a central hub to constitute a rotor. The rotor is set in rotation under the influence of wind on the blades, characterized by changes in velocity (kinetic energy), pressure and several other factors associated with the wind motion. Wind characteristics like velocity, pressure, direction of flow, etc., are stochastic in nature due to which the blades are required to be continuously turned or pitched for optimal orientation relative to wind direction. A pitch mechanism is typically employed to control the pitching or turning of the blades relative to the hub depending on wind speed and direction. In a wind turbine having a hydraulic pitch control, pitching is brought about by a hydraulic pitch actuator which is usually associated with an accumulator.

[004] Gas loaded type accumulators use gas as a substitute to spring-cushion in conjunction with a hydraulic fluid. The gas and the hydraulic fluid are separated by a thin diaphragm, bladder, piston, or bellows. Hence, these accumulators are known by the term “hydropneumatic accumulators”. Since hydro-pneumatic accumulators make use of a hydraulic fluid which is relatively incompressible, such accumulators provide quick response to power demand. This plays a crucial role in maintaining the fluid pressure of the hydraulic system, as well as in dampening the pressure shocks. Typically, the life expectancy of a hydro-pneumatic accumulator may be up to 20 years. However, they require frequent maintenance and servicing of gas (pneumatic) valves and refilling of gas/pneumatic fluid to necessary pressures in order to facilitate reliable and safe operation of the Wind Turbines. As pitch actuation systems control pitching of blades through several millions of pressure cycles, they should readily allow changing of gas (pneumatic) valves in the hydro-pneumatic accumulators. Therefore, the gas valve, as a consumable, needs replacement after certain period of operation in a Wind Turbine. Replacement of existing gas valves with new ones is an extremely cumbersome and expensive process, which may result in long idle (standstill or inoperative) times of a wind turbine. Replacement of a damaged gas valve may also demand disassembly of certain components in the pitch actuation system, which is not desirable. Further, conditions such as leakage in the gas valve may lead to retardation of gas pressure resulting in pulsations in the pressure of the hydraulic fluid during operation. This may severely hamper the performance of the accumulator, and the hydraulic system altogether, and may be accompanied with energy losses, which therefore, has to be avoided. In view of these shortcomings, there is a need for addressing the problems associated with leakage and damage of the gas valve in accumulators of wind pitch actuation systems.

[005] Present disclosure is directed to overcome one or more limitations stated above, or other such limitations associated with the prior arts.

SUMMARY OF THE DISCLOSURE

[006] One or more shortcomings of conventional accumulators are overcome, and additional advantages are provided through the accumulator as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

[007] In one non-limiting embodiment of the disclosure, a retrofittable valve for a hydropneumatic accumulator is disclosed. The retrofittable valve includes a body defining a first cavity extending from a distal end, where the first cavity is structured to removably accommodate at least a portion of a pre-existing valve of an accumulator. The body defines a second cavity extending from a proximal end of the body, and a passage interconnecting the first cavity and the second cavity. Further, the retrofittable valve includes an end port defined in the second cavity and having an inlet, and a valve member movably positioned in the passage. The valve member is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet of the end port and a port of the pre-existing valve of the accumulator.

[008] In an embodiment of the disclosure, the first cavity is defined with a plurality of threads configured to engage corresponding threads defined on at least the portion of the pre-existing valve of the accumulator.

[009] In an embodiment of the disclosure, the end port is configured to receive a fluid from a fluid power source, where the fluid is a pneumatic fluid. Further, the retrofittable valve is a unidirectional valve, and the valve member of the retrofittable valve is one of a poppet, a ball, and a spool.

[0010] In an embodiment of the disclosure, the body comprises a transfer member removably disposed in at least a portion of the passage, and the transfer member includes a channel configured to fluidly couple the passage with the port of the pre-existing valve of the accumulator.

[0011] In an embodiment of the disclosure, the valve member in the first position allows flow of a fluid from the end port to the port of the pre-existing valve, and the valve member in the second position restricts the flow of the fluid from the end port to the port of the pre-existing valve.

[0012] In an embodiment of the disclosure, the retrofittable valve includes at least one sealing member that is annularly interposed between at least one of the body and at least the portion of the pre-existing valve, between the body and the transfer member, between the body and the end port, and between the valve member and the end port.

[0013] In another non-limiting embodiment of the disclosure, a hydro -pneumatic accumulator is disclosed. The accumulator includes a cylinder defining a chamber, and a piston movably disposed in the chamber, where the piston divides the chamber into a first chamber and a second chamber. The first chamber is fluidly coupled to an actuation system through a hydraulic valve, and the second chamber is in fluid communication with a pneumatic fluid source through a pneumatic valve. The accumulator further includes a retrofittable valve having a body. The body defines a first cavity extending from a distal end, where the first cavity is structured to removably accommodate at least a portion of the pneumatic valve of an accumulator. The body also includes a second cavity extending from a proximal end, and a passage interconnecting the first cavity and the second cavity. Further, the retrofittable valve includes an end port defined in the second cavity and having an inlet, and a valve member movably positioned in the passage. The valve member is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet of the end port and a port of the pre-existing valve of the accumulator.

[0014] In an embodiment of the disclosure, the actuation system is a wind turbine pitch actuation system.

[0015] In an embodiment of the disclosure, the hydro-pneumatic accumulator comprises a cover removably secured to the pneumatic valve.

[0016] In an embodiment of the disclosure, the first chamber is structured to store a hydraulic fluid, and the second chamber is structured to store pressurized pneumatic fluid. Further, the pneumatic valve comprises a flow passage accommodating a pneumatic valve member, and the pneumatic valve member is adapted to move between a third position and a fourth position to selectively allow flow of the pneumatic fluid into the second chamber of the accumulator.

[0017] In yet another non-limiting embodiment of the disclosure, a method for preventing leakage in a pre-existing valve in an accumulator of a wind turbine pitch actuating system is disclosed. The method includes removing, an existing cover, secured to a pre-existing valve of an accumulator, and then assembling, a retrofittable valve, to at least a portion of the preexisting valve having at least one leakage zone. The retrofittable valve includes a body defining a first cavity extending from a distal end, where the first cavity is structured to removably accommodate at least a portion of the pre-existing valve of the accumulator. Further, the retrofittable valve includes a second cavity extending from a proximal end of the body, and a passage interconnecting the first cavity and the second cavity. An end port having an inlet is defined in the second cavity, and a valve member is movably positioned in the passage. The valve member is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet of the end port and a port of the pre-existing valve of the accumulator. The at least one leakage zone in the pre-existing valve is concealed by the body of the retrofittable valve when the retrofittable valve accommodates at least the portion of the pre-existing valve.

[0018] In still another embodiment of the disclosure, a kit having a retrofittable valve is disclosed. The kit having the retrofittable valve is structured to be assembled over a pre-existing valve of an accumulator to prevent leakage.

[0019] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0020] The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:

[0021] FIG. 1 illustrates a schematic sectional view of a hydro-pneumatic accumulator, according to some embodiments of the present disclosure;

[0022] FIG. 2A illustrates a schematic perspective view of the pneumatic valve in the hydropneumatic accumulator of FIG. 1 along with a cover in the exploded condition; [0023] FIG. 2B illustrates a schematic exploded perspective view of the accumulator and the pneumatic valve of FIG. 2 along with a retrofittable valve, according to some embodiments of the present disclosure; and

[0024] FIG. 3 illustrates a schematic sectional view of the pneumatic valve assembled with the retrofittable valve, according to some embodiments of the present disclosure.

[0025] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the pitch actuator and the seal assembly illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

[0026] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular form disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0027] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of an assembly, a system, a device, or a method, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the accumulator and the valves of the present disclosure may be employed in several disciplines/areas such as wind turbines, industrial systems, aircraft systems, heavy machineries and earth moving equipment, aquatic and terrestrial vehicles, and the like. However, all the sub-systems of the accumulator and the valves are not illustrated in the drawings of the disclosure for the purpose of simplicity.

[0028] The terms “comprises...a”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that an assembly, a system, a device, or a method comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such an assembly, a system, a device, or a method. In other words, one or more elements in the assembly, the system, the device, or the method proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly, the system, the device, or the method.

[0029] Embodiments of the present disclosure disclose a retrofittable valve for an accumulator of a wind turbine pitch actuation system. The pitch actuation system including an actuator takes part in adjusting the pitch angle of the blade to optimize performance. The accumulator serves as an energy reservoir for the pitch actuator and other components associated with the pitch actuator to readily compensate pressure fluctuations in the hydraulic system. A typical accumulator employed in pitch actuation systems uses both hydraulic and pneumatic working fluids and is popularly known as a “hydro-pneumatic” accumulator. With continuous operation of the accumulator, there may be tendencies where the pneumatic valve of the hydro-pneumatic accumulator may develop one or more leakage sites/zones. This may result in undesired fluctuations or even loss of pressure of the pneumatic fluid inside the accumulator. The present invention addresses this problem through a retrofittable valve which may be accommodated on the leakage site/zone of the pneumatic valve. The retrofittable valve includes a body defining a first cavity structured to removably accommodate at least a portion of a pre-existing valve of an accumulator. In an embodiment of the disclosure, the first cavity may be defined with a plurality of threads configured to engage corresponding threads defined on at least the portion of the pre-existing valve of the accumulator.

[0030] The body also defines a second cavity extending from a proximal end of the body, with a passage interconnecting the first cavity and the second cavity. A valve member is movably positioned in the passage. Further, the retrofittable valve includes an end port defined in the second cavity, with the end port having an inlet. The valve member in the passage is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet of the end port and a port of the pre-existing valve of the accumulator. In an embodiment of the disclosure, the valve member in the first position allows flow of a fluid from the end port to the port of the pre-existing valve, and the valve member in the second position restricts the flow of the fluid from the end port to the port of the pre-existing valve. The end port is configured to receive a fluid from a fluid power source, where the fluid is a pneumatic fluid. Further, the retrofittable valve is a unidirectional valve, and the valve member of the retrofittable valve is one of a poppet, a ball and a spool. Apart from the valve member, the body also has a transfer member removably disposed in at least a portion of the passage. The transfer member includes a channel configured to fluidly couple the passage with the port of the pre-existing valve of the accumulator. The body also has at least one sealing member annularly interposed between at least one of the body and at least the portion of the pre-existing valve, between the body and the transfer member, between the body and the end port, and between the valve member and the end port for the purposes of sealing.

[0031] The disclosure also disclose a hydro-pneumatic accumulator for a wind turbine pitch actuation system is disclosed. The accumulator includes a cylinder defining a chamber, and a piston movably disposed in the chamber, where the piston divides the chamber into a first chamber and a second chamber. The first chamber is fluidly coupled to a wind turbine pitch actuation system through a hydraulic valve, and the second chamber is in fluid communication with a pneumatic fluid source through a pneumatic valve. Further, the pneumatic valve comprises a flow passage accommodating a pneumatic valve member, and the pneumatic valve member is adapted to move between a third position and a fourth position to selectively allow flow of the pneumatic fluid into the second chamber of the accumulator. The accumulator further includes a retrofittable valve having a body explained in the previous paragraphs. In an embodiment of the disclosure, the hydro -pneumatic accumulator may include a cover removably secured to the pneumatic valve for the purpose of concealing the pneumatic valve.

[0032] Present disclosure also disclose a method for preventing leakage in a pre-existing valve in an accumulator of a wind turbine pitch actuating system is disclosed. The method includes removing, an existing cover, secured to a pre-existing valve of an accumulator, and then assembling, a retrofittable valve, to at least a portion of the pre-existing valve having at least one leakage zone such that leakage zone in the pre-existing valve is concealed by the body of the retrofittable valve.

[0033] The following paragraphs describe the present disclosure with reference to FIGS. 1 to 3. In the figures, the same element or elements which have similar functions are indicated by the same reference signs.

[0034] The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Further, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description. It is to be understood that the disclosure may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices or components illustrated in the drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions or other physical characteristics relating to the embodiments that may be disclosed are not to be considered as limiting, unless the claims expressly state otherwise. Hereinafter, preferred embodiments of the present disclosure will be descried referring to the accompanying drawings. While some specific terms of “above”, “right,” or “left”, “on”, and other terms containing these specific terms and directed to a specific direction will be used, the purpose of usage of these terms or words is merely to facilitate understanding of the present invention referring to the drawings. Accordingly, it should be noted that the meanings of these terms or words should not improperly limit the technical scope of the present invention.

[0035] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the disclosure illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates.

[0036] FIG. 1 illustrates a schematic sectional view of a hydro -pneumatic accumulator (50) in accordance with some embodiments of the disclosure. The hydro -pneumatic accumulator (50) is referred to as an accumulator (50) for the sake of simplicity. The accumulator (50) has a cylinder (51) [or a shell] which constitutes the accumulator body. The cylinder (51) is defined with a chamber which may receive and store fluids under pressure. As shown, the chamber inside cylinder (51) may be provided with a piston (52) which may move linearly or reciprocate under the influence of fluid pressure. The piston (52) may partition or divide the chamber into a first chamber (FC) and a second chamber (SC). Since the accumulator (50) is of hydropneumatic type, the first chamber (FC) may receive hydraulic fluid (HF) via hydraulic valve

(53), and the second chamber (SC) may receive a pneumatic fluid (PF) via a pneumatic valve

(54). In an embodiment, the first chamber (FC) may be in fluid communication with one or more elements of a hydraulic system, such that excess pressurized hydraulic fluid (HF) circulating through the hydraulic system may enter into the first chamber (FC). The pressurized hydraulic fluid (HF) so entering the first chamber (FC) is stored in the first chamber (FC) and is delivered back to the hydraulic system whenever there is pulsation (or fluctuation) in pressure of hydraulic fluid (HF) in any part of the hydraulic system. For instance, if the pressure drops in any part of the hydraulic system due to malfunctioning of any part, the hydraulic valve (53) may be prompted to open so that pressurized fluid in the first chamber (FC) is immediately discharged into the hydraulic system to restore necessary fluidic pressure in the hydraulic system. Thus, the accumulator (50) serves as an emergency power and pressure source to keep the hydraulic system running in times of emergencies. The accumulator (50) may also be designed to compensate even the slightest pulsations in the pressure of hydraulic fluid (HF) within the hydraulic system. In an exemplary embodiment, the hydro-pneumatic accumulator (50) of the present disclosure may be associated with a pitch actuation system [not shown] in a wind turbine [not shown], although the hydro-pneumatic accumulator (50) may be suitably employed in association with any other device or an apparatus or a mechanism in a hydraulic system.

[0037] The second chamber (SC), as shown, may be a pneumatic (gas) chamber which may be fluidly coupled to a pneumatic source via the pneumatic valve (53). In an embodiment, the pneumatic valve (54) may be concealed by a cover (55) to protect the valve from external influences including, but not limited to environmental conditions, mechanical and fluidic loads, and so on. The cover (54) may be removed for the purpose of charging the second chamber (SC) with a pneumatic fluid (PF) (typically air or any other inert gas like nitrogen) under pressure. Once required quantity of pneumatic fluid (gas) is charged, the cover (55) may be secured back to the pneumatic valve (54). The extremities of both first chamber (FC) and second chamber (SC) may be concealed with chamber heads (56) and (57) respectively which may be designed to sustain large fluid pressures inside chambers (FC) and (SC). In operation, the pneumatic fluid (PF) under required pressure may be charged into the second chamber (SC) via pneumatic valve (54) by removing the cover (55). Once the pneumatic fluid (PF) is charged, the cover (55) may be closed. Now, the excess pressurized hydraulic fluid (HF) may be let into first chamber (FC) via hydraulic valve (53), such that the piston (52) displaces towards left and compresses the pneumatic fluid (PF) in the second chamber (SC). Compression of the pneumatic fluid (PF) further increases the pressure of the pneumatic fluid (PF). When the requirement arises in the hydraulic system as explained previously, the hydraulic valve (53) may be opened. The compressed pneumatic fluid (PF) at relatively higher pressure expands and pushes the piston (52) towards right to force the hydraulic fluid (HF) out of the first chamber (FC) via hydraulic valve (53) under necessary pressure. In an embodiment, the piston (52) may form a fluid tight joint with the cylinder (51) walls and may be provided with seals (58) to ensure leak-proof joint, in addition to mitigation of friction. In another embodiment, a lubricant may be circulated at the interface of the piston (52) and the cylinder (51) wall for the purpose of lubrication.

[0038] FIG. 2A illustrates perspective view of a pneumatic valve (54, 5) connected to the accumulator cylinder (51) with a cover (55) shown in exploded condition. Reference is also made to FIG. 2B which shows exploded perspective view of the pneumatic valve (54) along with a retrofittable valve (7) of the present disclosure. Throughout the specification, the pneumatic valve (54) is alternately referred to as pre-existing valve identified by the reference numeral (5). The pneumatic valve (54), as described previously, may take part in charging and discharging pneumatic fluid (PF) under pressure. With a number of eventual charge-discharge cycles, especially under the compressed state of pneumatic fluid (PF) during operation, the pneumatic valve (54) may develop one or more leakage sites/zones. The leakage of pneumatic fluid (PF) may lead to several complications, including but not limited to loss of pressure in the second chamber (SC). This may in turn demand frequent charging of the pneumatic fluid (PF) into the second chamber (SC) which is unfeasible, and highly expensive. There is also loss in power which may hamper performance of the hydraulic system and the pitch actuation system, leading to improper pitch angle regulation, that is undesirable. On the other hand, removal and replacement of a leaky pneumatic valve (54) is an extremely complex and expensive procedure, which adds to operational cost of the system or the device, for example, the wind turbine. The replacement of pneumatic valve (54) also adds to idle/non-operational time of such a system or a device, for example, the wind turbine. To address these complications associated with a leaky pneumatic valve (54), the present disclosure provides a retrofittable valve (7) which may be readily fitted or assembled over the leaky pneumatic valve (54). When assembled, the retrofittable valve (7) may conceal the leakage site/zone in the pneumatic valve (7), and thereby may enable charging of the pneumatic fluid (PF) into the second chamber (SC) easily and without the need for replacing the leaky pneumatic valve (7). In an embodiment, susceptible leaky zones or sites may be the regions where transition in crosssection takes place in the valve, joints, interfaces, contact regions, enlargement of flow passages inside the valve, or any other zone where stress concentration effects are high or tend to be high. [0039] As shown in FIGS. 2A and 2B, the pneumatic valve (54) may have a flanged portion (5c) and a port (5a) which may be fluidly coupled to a pneumatic fluid source [not shown]. The pneumatic valve (54) may be attached to the cylinder (51) through an enlarged portion (5e), as shown in FIG. 2A. In an embodiment, the enlarged potion (5e) may be in the form of a nut which may secure the pneumatic valve (54) with the cylinder (51). After the pneumatic fluid (PF) is charged into the second chamber (SC), the cover (55) may be secured to the pneumatic valve (54) such that the flanged portion (5c) and the port (5a) may reside inside the cover (55) for concealing the pneumatic valve (54). In an embodiment, the cover (55) may be threadingly accommodated over the port (5a) and the flanged portion (5c) of the pneumatic valve (54), where the flanged portion (5c) may be defined with male (external threads), and the cover (55) may be defined with female (internal) threads. Now, referring to FIG. 2B, when at least one leakage site [not shown] is identified in the pneumatic valve (54), the cover (55) may be detached and the retrofittable valve (7) may be removably assembled over the pneumatic valve (54). The retrofittable valve (7) may have a proximal end (P) which may be identical to the flanged portion (5c) of the pneumatic valve (54). Similarly, the retrofittable valve (7) may have an end port (9) which may be identical to the port (5a) of the pneumatic valve (54). In an embodiment, the end port (9) and the port (5a) may have exactly same geometry and dimensions, such that the retrofittable valve (7) may maintain same compatibility (fit or assembly) with the pneumatic fluid source, as that of the pneumatic valve (54).

[0040] Further, the proximal end (P) of the retrofittable valve (7) and the flanged portion (5c) may have exactly same geometry and dimensions, such that the proximal end (P) may have same compatibility with the cover (55) as that of the flanged portion (5c). In yet another embodiment, the flanged portion (5c) of the pneumatic valve (54) may be defined with male (external) threads, and the retrofittable valve (7) may be defined with female (internal) threads [explained with reference to FIG. 3 later]. This allows the retrofittable valve (7) to be threadingly engaged/assembled with the pneumatic valve (54). When at least one leakage site/zone is identified in the vicinity of the flanged portion (5c) and/or the port (5a), assembly of the retrofittable valve (7) above the flanged portion (5c) may conceal the identified leakage site/zone, while the retrofittable valve (7) still allows charging of the pneumatic fluid (PF) through the end port (9). This way, removal and replacement of the pneumatic valve (54) when it is leaking may be avoided, and consequently, shutting down/restart of the system or the device, such as the wind turbine, for replacement of the pneumatic valve (54) may be averted. In an embodiment, a spare retrofittable valve (7) and a standard torque tool, including but not limited to a wrench or a spanner may be placed in the vicinity of the accumulator for ready and quick assembly of the spare retrofittable valve (7) over the defective/leaky pneumatic valve (54).

[0041] FIG. 3 illustrates sectional view of the pneumatic valve (54) assembled with the retrofittable valve (7), in accordance with some embodiments of the disclosure. As shown, the pneumatic valve (54) [alternately referred to as “pre-existing valve (5)”] may have the flanged portion (5c), the enlarged portion (5e) in the form of a lock nut, and a connecting portion (5b) which bridges the pre-existing valve (5) with the cylinder (51). The flanged portion (5c) and the enlarged portion (5e) may be defined with a flow passage (6a) to accommodate the port (5a). The port (5a) may be integrally defined or inserted from outside within the flow passage (6a). The port (5a) in turn defines a central passage (CP) which may allow the pneumatic fluid (PF) entering from the port (5a) towards the connecting portion (5b) and subsequently into the cylinder (51) of the accumulator (50). The central passage (CP) may be provided with a pneumatic valve member (6b) which may selectively allow and restrict flow of the pneumatic fluid (PF) entering from the port (5a) towards the connecting portion (5b) and subsequently into the cylinder (51). In an embodiment, the pneumatic valve member (6b) includes, but not limited to a spring-loaded poppet, spool or a ball member. The spring (6c) may contract under the pressure [above a threshold value] of the pneumatic fluid (PF) when it enters and may extend when the pressure of the pneumatic fluid (PF) drops below the threshold value to close the pneumatic valve member (6b) and restrict the flow. The pneumatic fluid (PF) coming into the flow passage (6a) may pass through the channel (5d) defined in the connecting portion (5b) to enter into the cylinder (51). In an embodiment, sealing members (12) may be provided at various interfaces to ensure sealing joints at said interfaces.

[0042] Further, as shown in FIG. 3, the retrofittable valve (7) includes a body (7a) which may define a first cavity (8a) extending from a distal end (D) of the retrofittable valve (7). The first cavity (8a) may removably accommodate at least a portion of the pre-existing valve (5) of the accumulator (50). In an embodiment of the disclosure, the first cavity (8a) may be defined with a plurality of threads [female or internal threads] configured to engage corresponding threads [male or external threads] defined on the flanged portion (5c) of the pre-existing valve (5). The interface between the first cavity (8a) and the flanged portion (5c) may be provided with one or more seals (12) at the distal end for sealing purposes. The threading engagement allows easy assembly and disassembly of the retrofittable valve (7) relative to the pre-existing valve (5). In an embodiment, when the retrofittable valve (7) is threadingly connected to the pre-existing valve (5) as shown in FIG. 3, the first cavity (8a) may be concentrically and co-axially aligned with the central passage (CP) of the port (5a), as well as with the flow passage (6a) of the preexisting valve (5) to allow flow of the pneumatic fluid (PF). Further, the first cavity (8a) may continue into a second cavity (8b) through a passage (10a) present at the proximal end (P) or substantially extending through the proximal end (P). This way, the second cavity (8b), the passage (10a) and the first cavity (8a) of the retrofittable valve (7), together with the central passage (CP), flow passage (6a) and the channel (5d) define a coaxial, concentric flow path for the pneumatic fluid (PF), represented by the flow direction (FD).

[0043] When assembled, the retrofittable valve (7) may conceal one or more leakage site(s)/zone(s) present in the vicinity of the flanged portion (5c) and/or the port (5a). The retrofittable valve (7) may still allow charging of the pneumatic fluid (PF) through the end port (9) and the inlet (9a), while preventing leakage of the pneumatic fluid (PF) from the one or more leakage site(s)/zone(s) present in the vicinity of the flanged portion (5c) and/or the port (5a) of the pre-existing valve (5). This way, detachable assembly of the retrofittable valve (7) over the pre-existing valve (5) prevents detachment and replacement of the pre-existing valve (5) when leakage is detected. Consequently, shutting down/restart of the system or the device, including but not limited to the wind turbine, for the purpose of replacement of the pre-existing valve (5) may be avoided.

[0044] In an embodiment as shown in FIG. 3, a transfer member (11) may be removably disposed in the passage (10a) to bridge the passage (10a) with the central passage (CP). The transfer member (11) may include a channel (I la) configured to fluidly couple the passage (10a) with the port (5a) of the pre-existing valve (5). In an embodiment of the disclosure, assembly of the retrofittable valve (7) together with the transfer member (11) may partly press/push the pneumatic valve member (6b) to keep the pneumatic valve member (6b) partially open at all times. This way, when the retrofittable valve (7) is assembled over the preexisting valve (5), the pre-existing valve (5) may always remain in partially or substantially open condition to allow flow of pneumatic fluid (PF) at any instant of time. This may be beneficial when there is loss of sensitivity and/or stiffness of the spring (6c).

[0045] Further, as shown in FIG. 3, a valve member (10b) may be movably positioned in the passage (10a) and substantially inside the second cavity (8b). An end port (9) having an inlet (9a) may be integrally defined or inserted from outside into the second cavity (8b), such that the valve member (10b) may selectively open or close the passage (10a) defined in the end port (9) under biasing force of the elastomeric member such as spring (10c). To attain opening and closing conditions, the valve member (10b) in the passage (10a) may be adapted to move or actuate between a first position and a second position under the pressure of the pneumatic fluid (PF) and resisting spring (10c) force. Accordingly, the valve member (10b) may be configured to selectively establish [allow or restrict] fluid communication between the end port (9) and the port (5a) of the pre-existing valve (5) via the transfer member (11). In an embodiment of the disclosure, the valve member (10b) in the first position allows flow of a fluid from the end port (9) to the port (5a) of the pre-existing valve (5), and the valve member (10b) in the second position restricts the flow of the fluid from the end port (9) to the port (5a) of the pre-existing valve (5). In another embodiment, the inlet (9a) of the end port (9) is configured to receive a fluid, including but not limited to the pneumatic fluid (PF) from a fluid power source [not shown] .

[0046] Furthermore, the retrofittable valve (7) may be a unidirectional valve which may allow flow of the pneumatic fluid (PF) in the direction indicated by (FD) only. In an embodiment, the valve member (10b) of the retrofittable valve (7) may be one of a poppet, a ball and a spool biased by the spring (10c). In an embodiment of the disclosure, the body (7a) may also contain at least one sealing member (12) annularly interposed between at least one of the body (7a) and at least the portion of the pre-existing valve (5), between the body (7a) and the transfer member

(11), between the body (7a) and the end port (9), and between the valve member (10b) and the end port (9) for the purposes of sealing. In another embodiment, the at least one sealing member

(12) may be manufactured using an elastomeric material selected from a class of polymers like Nitrile (Buna), Neoprene, Ethylene Propylene (EPDM Rubber), Silicone, Fluorocarbon (Viton), and PTFE (Teflon) and combinations thereof.

[0047] Now, referring back to FIGS. 2A and 2B together with FIG. 3, a method for preventing leakage in the pre-existing valve (5) is described. The method involves firstly removing the existing cover (55) secured to the pre-existing valve (5), as shown in FIG. 2A. This is followed by a second step of removably assembling the retrofittable valve (7) to conceal the one or more leakage site(s)/zone(s) present in the pre-existing valve (5) [FIG. 2B], as explained in the previous paragraphs. Once the retrofittable valve (7) is removably assembled over the preexisting valve (5), the inlet (9a) of the end port (9) may be fluidly connected to the pneumatic fluid source to charge (admit) the pneumatic fluid (PF). The pneumatic fluid (PF) entering the inlet (9a) may exert pressure on the valve member (10b) to compress the spring (10c), and consequently, render the valve member (10b) in the first position or substantially close to the first position [open condition]. This allows the pneumatic fluid (PF) to further advance into the channel (I la) of the transfer member (11), represented by the flow direction (FD). The pneumatic fluid (PF) then strikes the pneumatic valve member (6b) in the central passage (CP), and exerts a pressure on the pneumatic valve member (6b) to compress the spring (6c). Under the spring (6c) compression, the pneumatic valve member (6b) actuates and opens further [since the pneumatic valve member (6b) is already opened by assembly of the retrofittable valve (7)]. This allows the pneumatic fluid (PF) to further advance towards the flow passage (6a), and subsequently into the second chamber (SC) of the cylinder (51) via the channel (5d) in the connecting portion (5b). Once the pneumatic fluid (PF) is charged to required pressure, a cover (55’) may be secured to the proximal end (P) of the retrofittable valve (7) to sustain the pressure inside second chamber (SC) of the accumulator (50). In an embodiment, a kit [not shown] containing one or more spare retrofittable valve(s) (7) and necessary tools, including but not limited to wrenches, pliers, drivers, spanners and so on may be positioned proximal to the pre-existing valve (5) for quick and easy assembly in the event of leakage.

[0048] The retrofittable valve (7) discussed in the present disclosure provides number of advantages. One of the advantages is that the consistency of the retrofittable valve (7) in terms of geometry and dimensions with those of pre-existing valve (5). This allows the retrofittable valve maintain compatibility with the charging setup and the pneumatic fluid source, without the need for design changes or auxiliary components for connections. Another advantage is that the provision of removable assembly (threading engagement) of the retrofittable valve over the pre-existing valve, which is extremely simple, quick, and not requiring highly skilled labour and/or sophisticated tools/equipment. The quick and ready assembly of the retrofittable valve also cuts the costs involved in replacement or repair of the leaky pre-existing valve. In addition, the assembly step reduces idle time/non-operating time of the system or the device, for example, a wind turbine, if at all a repair/replacement of the leaky pre-existing valve was performed. If a leakage in the retrofittable valve (7) is detected, it may be easily removed and replaced with a new retrofittable valve (7) to restore the accumulator (50) operation.

Equivalents:

[0049] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0050] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system) having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

[0051] Table of Reference Numerals:

Claims

Claims:

1. A retrofittable valve (7) for a hydro-pneumatic accumulator (50), the retrofittable valve (7) comprising: a body (7a), defining: a first cavity (8a) extending from a distal end (D), wherein the first cavity (8a) is structured to removably accommodate at least a portion of a preexisting valve (5) of an accumulator (50), a second cavity (8b) extending from a proximal end (P) of the body (7a), and a passage (10a) interconnecting the first cavity (8a) and the second cavity (8b), an end port (9) defined in the second cavity (8b) and having an inlet (9a); and a valve member (10b) movably positioned in the passage (10a), wherein the valve member (10b) is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet (9a) of the end port (9) and a port (5a) of the pre-existing valve (5) of the accumulator (50).

2. The retrofittable valve (7) as claimed in claim 1, wherein the first cavity (8a) is defined with a plurality of threads configured to engage corresponding threads defined on at least the portion of the pre-existing valve (5) of the accumulator (50).

3. The retrofittable valve (7) as claimed in claim 1, wherein the end port (9) is configured to receive a fluid from a fluid power source, and wherein the fluid is a pneumatic fluid (PF).

4. The retrofittable valve (7) as claimed in claim 1, wherein the retrofittable valve (7) is a unidirectional valve, and the valve member (10b) of the retrofittable valve (7) is one of a poppet, a ball, and a spool.

5. The retrofittable valve (7) as claimed in claim 1, wherein the body (7a) comprises a transfer member (11) removably disposed in at least a portion of the passage (10a), and wherein the transfer member (11) includes a channel (I la) configured to fluidly couple the passage (10a) with the port (5a) of the pre-existing valve (5) of the accumulator (50). The retrofittable valve (7) as claimed in claim 1, wherein the valve member (10b) in the first position allows flow of a fluid from the end port (9) to the port (5a) of the preexisting valve (5), and the valve member (10b) in the second position restricts the flow of the fluid from the end port (9) to the port (5a) of the pre-existing valve (5). The retrofittable valve (7) as claimed in claim 1 comprises at least one sealing member (12) annularly interposed between at least one of the body (7a) and at least the portion of the pre-existing valve (5), between the body (7a) and the transfer member (11), between the body (7 a) and the end port (9), and between the valve member (10b) and the end port (9). A hydro-pneumatic accumulator (50), comprising: a cylinder (51) defining a chamber; a piston (52) movably disposed in the chamber, wherein the piston (52) divides the chamber into a first chamber (FC) and a second chamber (SC); wherein the first chamber (FC) is fluidly coupled to an actuation system through a hydraulic valve (53), and the second chamber (SC) is in fluid communication with a pneumatic fluid source through a pneumatic valve (54); and; a retrofittable valve (7), comprising: a body (7a), defining: a first cavity (8a) extending from a distal end (D), wherein the first cavity (8a) is structured to removably accommodate at least a portion of the pneumatic valve (54) of an accumulator (50), a second cavity (8b) extending from a proximal end (P) of the body (7 a), and a passage (10a) interconnecting the first cavity (8a) and the second cavity (8b), an end port (9) defined in the second cavity (8b) and having an inlet (9a); and a valve member (10b) movably positioned in the passage (10a), wherein the valve member (10b) is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet (9a) of the end port (9) and a port (5a) of the pneumatic valve (54) of the accumulator (50). The hydro-pneumatic accumulator (50) as claimed in claim 8, wherein the actuation system is a wind turbine pitch actuation system. The hydro-pneumatic accumulator (50) as claimed in claim 8 comprises a cover (55) removably secured to the pneumatic valve (54). The hydro-pneumatic accumulator (50) as claimed in claim 8, wherein the first chamber (FC) is structured to store a hydraulic fluid (HF), and the second chamber (SC) is structured to store a pneumatic fluid (PF). The hydro-pneumatic (50) accumulator as claimed in claim 8, wherein the pneumatic valve (54) comprises a flow passage (6a) accommodating a pneumatic valve member (6b), and wherein the pneumatic valve member (6b) is adapted to move between a third position and a fourth position to selectively allow flow of the pneumatic fluid (PF) into the second chamber (SC) of the accumulator (50). The hydro-pneumatic (50) accumulator as claimed in claim 8, wherein each of the valve member (10b) and the pneumatic valve member (6b) is biased by an elastomeric member (10c, 6c), and wherein the elastomeric member (10c, 6c) is an axial spring. A method for preventing leakage in a pre-existing valve (5) in an accumulator (50), the method comprising: removing, an existing cover (55), secured to a pre-existing valve (5) of an accumulator (50); and assembling, a retrofittable valve (7), to at least a portion of the pre-existing valve (5) having at least one leakage zone, the retrofittable valve (7) comprising: a body (7a), defining: a first cavity (8a) extending from a distal end (D), wherein the first cavity (8a) is structured to removably accommodate at least a portion of the pre-existing valve (5) of the accumulator (50), a second cavity (8b) extending from a proximal end (P) of the body (7 a), and a passage (10a) interconnecting the first cavity (8a) and the second cavity (8b), an end port (9) defined in the second cavity (8b) and having an inlet (9a); and a valve member (10b) movably positioned in the passage (10a), wherein the valve member (10b) is adapted to move between a first position and a second position to selectively establish fluid communication between the inlet (9a) of the end port (9) and a port (5a) of the pre-existing valve (5) of the accumulator (50); wherein, the at least one leakage zone is concealed by the body (7 a) of the retrofittable valve (7) when the retrofittable valve (7) accommodates at least the portion of the preexisting valve (5). A kit comprising a retrofittable valve (7) of claim 1 being structured to be assembled over a pre-existing valve (5) of an accumulator (50) to prevent leakage.