Flow regulation valve

Abstract

"FLOW REGULATION VALVE". A valve assembly that includes a valve body defining a fluid passage. The first and second ends of the fluid passage define first and second fluid flow holes. A spring and piston are located in the fluid passage. The piston has a displacement length extending between the first and second positions with a third position located between them. The spring guides the piston from the first to the third position and is located outside the axial piston passage. The piston at least partially defines a first, second and at least a third opening. The first opening defines a variable constriction that increases in size when the piston moves from the first to the third position. The piston end wall defines the second opening and the piston side wall defines the third opening. The movement of the piston from the third to the second position exposes the third opening, increasing the area of ​​the second orifice.

Description

1526 i> > · FLOW REGULATING VALVE FUNDAMENTALS OF THE INVENTION 1. Field of the Invention The present invention relates to valves and, more specifically, to a flow regulating valve that regulates fluid flow in one direction and allows generally unregulated fluid flow in the opposite direction. 2. Description of the Related Technique In vehicles employing hydraulic systems, it is known to employ valves that limit the flow of hydraulic fluid through a fluid line leading to a hydraulic actuator, such as a motor or cylinder, to a maximum flow rate. For example, in a mower and threshing machine, it is known to use an internal combustion engine to drive a hydraulic pump. The hydraulic pump supplies pressurized hydraulic fluid to a hydraulic circuit. Each of the driven wheels of the mower and threshing machine may include a separate hydraulic motor that is driven by the hydraulic circuit. Each of the motors may be located in a separate circuit communicating with the hydraulic circuit. By reversing the direction of flow through the individual circuits with the use of a reversing pump, reversing valve, or other suitable device, the rotational direction in which the wheel is driven can also be reversed. In such a circuit, it is known to provide two flow control valves, one on each side of the hydraulic motor. The flow control valves are positioned in the circuit so that one valve limits the flow of hydraulic fluid through the hydraulic motor, or other hydraulically driven device, to a maximum flow rate in one direction, while the other valve limits the flow to a maximum flow rate in the opposite direction. During operation, while one valve is regulating the flow, it is desirable that the other valve in the circuit, which is not performing a flow control function, allows fluid to pass freely through it with minimal pressure drop and without restricting the fluid flow rate. By providing flow control valves in each individual hydraulic motor circuit, if one of the driven wheels begins to slip, the flow of hydraulic fluid to the slipping wheel will be limited to the maximum flow rate allowed by the valve. Limiting the flow rate of hydraulic fluid to the slipping wheel prevents excess hydraulic fluid from depriving the remaining wheels of sufficient hydraulic fluid flow, as well as preventing the slipping wheel from rotating, which could result in damage to the lawn, plants, and / or tires. Figures 1 and 2 illustrate a known example of such a flow control valve. The valve 10 shown in Figures 1 and 2 includes a valve body 12 that receives the outlet adapter 14 with an O-ring 15 or other suitable device providing a seal between them. The valve body 12 and the outlet adapter 14 include axially extending passages 16 and 18, respectively, to carry the hydraulic fluid. The valve 10 also includes the piston 20, the deflector element 22 and the spring 24 which provide regulation of fluid flow through the valve. Valve 10 limits the flow of hydraulic fluid to a predetermined design flow rate when hydraulic fluid is flowing through valve 10 in the direction indicated by the flow arrows 26 in Figure 1. When hydraulic fluid is flowing in this regulated direction, piston 20 will initially be in the position shown in Figure 2 where spring 24 guides piston 20 away from deflector 22 at a point where radial flange 28 engages valve body 12.The rate of hydraulic fluid flow through valve 10 depends on the pressure differential across valve 10. When the flow of hydraulic fluid through the calibrated orifice 30 in the direction indicated in Figure 1 increases, the pressure differential acting on piston 20 will also increase. When the pressure differential and the resulting force on piston 20 exceed the guiding force of spring 24, piston 20 will be oriented in the direction of deflector 22. As piston 20 moves in the direction of deflector 22, the annular orifice 32 defined between piston 20 and deflector element 22 decreases in size, thereby restricting the fluid flow through the valve. By appropriately selecting the dimensions of the spring and valve, valve 10 can be used to limit the fluid flow in the direction indicated in Figure 1 to a predetermined maximum flow rate. In Figure 2, the hydraulic fluid flow through valve 10 is in the opposite return flow direction as indicated by the flow arrows 27. When the fluid is flowing in this return direction, there is no fluid flow force to oppose the spring guidance force 24, and the annular orifice 32 maintains a constant dimension independent of the flow rate or pressure differential of the hydraulic fluid. Consequently, valve 10 does not positively control the flow rate of the hydraulic fluid through the valve in the return direction, and the flow is limited by the dimension of the measuring orifice 30. In other words, the valve does not regulate the fluid flow through the valve when the fluid is flowing in the direction indicated by the arrows 27 in Figure 2, but instead, the limited dimension of the measuring orifice 30 restricts the fluid flow through the valve, resulting in a pressure drop across the valve and undesirable energy losses and fluid heating. Another example of a known flow compensation valve assembly is shown in U.S. Patent No. 5,320,135. The valve assembly described in this patent can be used with hydraulic cylinders found in hydraulic platform lifts. The compensating valve 1 includes a valve body 10 receiving a sleeve 12 having an upper part 16 and a lower part 18. A piston 20 is received sliding within the sleeve 12 and, as best seen in Figures 3-6, a spring 30 is provided between the bottom end 19 of the lower sleeve part 18 and the top end wall 21 of the piston 20. The piston 20 includes an axial main orifice 22 and a pair of discharge orifices 23a and 23b in its side wall periphery part.In operation, as shown in Figure 3, when the hydraulic fluid is moving from the pump to the hydraulic cylinder from borehole 44 to borehole 41, as shown by the arrows, the hydraulic fluid moves around and between the lower sleeve part 18 and the inner wall part 54 of the valve body 10 and inside the sleeve 12 through the orifices 15a and 15b. As shown, during this condition, the piston 20 is forced in the direction of borehole 41, thus causing the discharge orifices 23a and 23b to be placed in communication with the discharge region 56 of the sleeve 12. Thus, the flow is supplied through the side discharge ports 23a and 23b, as well as through the main axial port 22. When the flow direction is reversed, with the fluid flowing from the hydraulic cylinder to the pump, there is little or no back pressure as shown in the Figure. 4. Spring 30 keeps piston 20 in the fully extended position, thus allowing flow through orifices 23a and 23b. When the flow from the hydraulic cylinder to the motor is increased, as shown in Figure 5, piston 20 acts against spring 30 and moves within the sleeve 12 of this cylinder. In this way, the fluid discharge ports 23a and 23b are closed so that flow occurs only through the main axial port 22. When the hydraulic fluid pressure increases further as shown in Figure 6, the piston exerts an even greater force against the spring 30, moving further into the sleeve 12 so as to partially block the outlet ports 15a and 15b. While the valve assembly described in U.S. Patent No. 5,320,135 can effectively regulate the flow of hydraulic fluid to the hydraulic cylinder of a hydraulic lift, it is not without drawbacks. If such a valve assembly were used to limit the flow of hydraulic fluid to a hydraulic motor by placing the valve in a hydraulic motor circuit, as shown in Figures 4-6 of U.S. Patent No. 5,320,135, the fluid flow would initially have to overcome the resistance of spring 30 before the valve is moved from the condition shown in Figure 4 to that shown in Figure 5. This could result in a relatively uneven transition where the fluid flow initially increases rapidly while the valve was in the condition of Figure 4 and then decreases rapidly when the valve is moved to the condition shown in Figure 5 where orifices 23a and 23b are closed.The flow rate could then resume its increase until the valve begins to close orifices 15a and 15b as shown in Figure 6. While this may be acceptable for the operation of a hydraulic lift, such a transition could result in the erratic and unacceptable operation of a wheel driven by a hydraulic motor. This erratic transition would likely be particularly evident when the fluid flow direction for such a hydraulic motor was reversed and the fluid flow was initially being increased. An improved valve assembly is desired. 5 which can be used to efficiently regulate fluid flow in one direction for a hydraulic device without rapid and irregular transitions and, in the other direction, allow unregulated fluid flow with minimal restriction, thus minimizing energy losses and fluid heating. SUMMARY OF THE INVENTION The present invention provides a flow regulating valve that regulates the flow rate of a fluid through the valve in one direction and allows return flow to flow efficiently through the valve in the opposite direction. The invention comprises, in one embodiment thereof, a valve assembly including a valve body defining a fluid passage extending through the valve body. The fluid passage has a first end and a second opposite end wherein the first end defines a first orifice through which fluid is communicated with and from the fluid passage and the second end defines a second orifice through which fluid is communicated with and from the fluid passage. A guiding element and a valve element are also provided. The valve element is movably arranged within the fluid passage inside the valve body and has a displacement length extending from a first position relative to the valve body to a second position relative to the valve body.The guiding element orients the valve element along the displacement length of the first position towards a third position located between the first and second positions. The valve element at least partially defines a first variable opening (e.g., variable annular opening 98), a second opening (e.g., calibrated orifice 62), and at least one third opening (e.g., openings 64). The first opening defines a variable constriction in the fluid passage between the first and second ends and has a size that progressively increases as the valve element moves from the first position to the third position.The second opening and at least one third opening define the second orifice wherein, when the valve element is disposed between the first and third positions, the second orifice is defined only substantially by the second opening and, when the valve element is in the second position, the second orifice is defined by the second opening and at least one third opening. The valve element defines a passage extending from the second orifice to the first opening and the guiding element is located outside the valve element passage. The fluid flows through the fluid passage in a first direction from the second end to the first end and exerts pressure on the valve element and guides the valve element to the first position.The flow of fluid through the fluid passage in a second direction, from the first end to the second end, exerts pressure on the valve element and orients the valve element to the second position. The invention comprises, in another embodiment thereof, a valve assembly including a valve body defining a fluid passage extending through the valve body. The fluid passage has a first end and a second opposite end. The first end defines a first orifice through which fluid communicates with and from the fluid passage, and the second end defines a second orifice through which fluid communicates with and from the fluid passage. A guiding element and a valve element are also provided. The valve element is movably arranged within the fluid passage inside the valve body and has a displacement length extending from a first position relative to the valve body to a second position relative to the valve body.The valve element also defines a third position along the travel length, where the third position is located between the first and second positions. The valve element defines at least partially a first variable opening and a second orifice. The first opening defines a variable constriction in the fluid passage between the first and second ends and has a dimension that progressively increases as the valve element moves from the first position to the third position. The second orifice is variably sized, where the second orifice defines a first area providing fluid communication with the fluid passage when the valve element is in the third position and defines a second area providing fluid communication with the fluid passage when the valve element is in the second position, with the second area being larger than the first area.The displacement length includes a portion of oriented displacement between the first and third positions, where the guiding element orients the valve element from the first position to the third position, and a portion of non-oriented displacement between the third and second positions, where the valve element is not oriented with respect to the guiding element. Fluid flow through the fluid passage in a first direction, from the second end to the first end, exerts pressure on the valve element and orients the valve element to the first position. Fluid flow through the fluid passage in a second direction, from the first end to the second end, exerts pressure on the valve element and orients the valve element to the second position. The invention comprises, in yet another embodiment thereof, a valve assembly including a valve body defining a fluid passage extending through the valve body. The fluid passage has a first end and a second opposite end. The first end defines a first orifice through which fluid is communicated to and from the fluid passage, and the second end defines a second orifice through which fluid is communicated to and from the fluid passage. A spring is disposed within the fluid passage and is engaged with the valve body. A piston is movably disposed within the fluid passage and is operably coupled with the spring. The piston has a travel length extending from a first position in the fluid passage to a second position in the fluid passage.The piston also defines a third position along the displacement length, where the third position is located between the first and second positions. The piston has a substantially cylindrical side wall defining a passage extending axially through the piston and an end wall located at a first axial end of the piston. The piston defines at least partially a first opening, a second opening, and at least a third opening. The first opening is in communication with the axial piston passage and is located at a second axial end of the piston opposite the first axial end. The first opening defines a variable constriction in the fluid passage between the first and second ends and has a dimension that progressively increases as the piston moves from the first position to the third position.The piston's end wall defines a second opening in communication with the axial piston passage, and the piston's side wall defines at least a third position near the end wall. When the piston is positioned between the first and third positions, the second orifice is defined only substantially by the second opening, and when said piston is in the second position, the second orifice is defined by the second opening and at least a third opening. The spring is located outside the axial piston passage. The fluid flow through the fluid passage in a first direction from the second end to the first end exerts pressure on the piston and orients the piston to the first position. The fluid flow through the fluid passage in a second direction from the first end to the second end exerts pressure on the piston and orients the piston to the second position. One advantage of the present invention is that it minimizes restriction and improves the return flow of fluid through the valve, thereby reducing energy losses and heat generated by the return fluid flow through the valve in the unregulated direction. Additionally, by removing the spring from inside the piston, the piston calibration orifice can be enlarged, thereby reducing the pressure drop experienced by the fluid flowing through the calibration orifice and improving valve operation for fluid flow in both regulated and unregulated flow directions. The regulation of fluid flow through the valve assembly in the regulated flow direction is also relatively smooth without abrupt transitions when the flow rate changes. BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned aspects and objectives of this invention, and the manner of achieving them, will become clearer and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which: Figure 1 is a cross-sectional view of a conventional flow control valve. Figure 2 is another cross-sectional view of the conventional flow control valve of Figure 1. Figure 3 is an exploded view of a valve according to the present invention. Figure 4 is a cross-sectional view of the valve in Figure 3 where the fluid is flowing in the regulated direction at less than the maximum flow rate. Figure 5 is another cross-sectional view of the valve from Figure 3 where the fluid is flowing in the regulated direction at the maximum flow rate. Figure 6 is another cross-sectional view of the valve from Figure 3 where the fluid is flowing in the unregulated direction. The corresponding reference characters indicate corresponding parts across all the various views. Although the exemplification shown here illustrates one embodiment of the invention, the embodiment described below is not intended to be exhaustive or to be constructed as limiting the scope of the invention to the precise forms described. DETAILED DESCRIPTION OF THE INVENTION A valve assembly 40 according to the present invention is shown in an exploded view in Figure 3. The valve assembly 40 includes a valve body 42 having a passage defined by three axially aligned cylindrical bore sections 44, 46, 48 of different diameters. In the illustrated embodiment, the valve element 50 takes the form of a piston 50 arranged alternately in the valve body 42. The piston 50 includes a cylindrical side wall 52 that defines the interior passage 54 extending from the first axial end 56 of the piston 50 to the second opposite axial end 58 of the piston 50. An end wall 60 is located at the first axial end 56 and includes a measuring orifice 62. A plurality of circumferentially spaced openings 64 are located in the side wall 52 near the first axial end 56.The second axial end 58 of the piston 50 is open, that is, it does not include an end wall or otherwise define a restriction within the axial passage 54. The radially external surface of the side wall 52 at the second axial end 58 forms a tapered surface 66 that cooperates with the deflector element 78. The piston 50 also includes a flange extending radially outward 68. A coupling element 70, which takes the form of a washer in the illustrated embodiment, is located between the flange 68 and the guide element 76. The washer 70 includes a planar annular element 72 having a flange 74 located on its outer circumference. In the illustrated embodiment, the guide element 76 is a helical spring, and the part of the spring 76 that directly engages the washer 70 is seated within the flange 74 to maintain proper engagement of the spring 76 with the washer 70 during the operation of the valve 40. A deflector element 78 is also shown in Figure 3 and includes a cylindrical side wall 80 having a first end 82. The first end 82 of the deflector 78 cooperates with the second axial end 58 and the tapered surface 66 to define a variable opening 98. A radially projecting flange 84 is used in securing the deflector 78 within the valve 40. An interior partition 86 extends through the interior space of the deflector and includes a drain hole 88. Circumferentially spaced openings 90 are located in the side wall 80 with the partition 86 being located between the first end 82 and the openings 90. The deflector 78 is fixed within the valve assembly 40 between the adapter body 92 and the valve body 42. The deflector 78 is held in place by the spring 76 which guides the radial flange 84 into engagement with the adapter body 92. Alternative methods of securing the deflector 78 may also be employed. Such alternative retention devices to prevent the deflector element 78 from moving in the direction of the piston 50 during reverse flow conditions could include a snap ring seated in an annular groove in the cylindrical bore 48, an annular flange projecting radially inward into the bore 48, or a step in the bore 48 that would engage the radial flange 84. Dashed lines 48a in Figure 3 schematically illustrate such an alternative retention device that could be formed by the snap ring or annular flange.The function of the baffle 78 could also be incorporated into another component part of the valve assembly 40, such as the adapter body 92 or the valve body 42. For example, the baffle 78 could be integrally formed with the adapter body 92. The adapter body 92 includes an internal fluid passage 94 which is in fluid communication with the hole 48, thereby forming a fluid passage 100 extending through the valve assembly 40 between the first hole 102 and the second hole 104. An O-ring 96 is used to provide a seal between the adapter body 92 and the valve body 42. Other suitable means of providing a seal may also be employed. Figure 4 illustrates valve assembly 40 with fluid flowing in a first direction from the second end 105 of fluid passage 100 to the first end 103 of fluid passage 100 as indicated by flow arrows 106. The flow direction illustrated in Figure 4 is the regulated flow direction of valve assembly 40. As shown in Figure 4, the fluid flow path through fluid passage 100 of valve assembly 40 begins with the fluid entering passage 100 through the second orifice 104. When piston 50 is in the position shown in Figure 4, the second orifice is defined only by an opening 62 that forms a calibrated orifice. The flow enters the axial passage 54 through the second orifice 104 and subsequently passes through the variable opening 98 to enter the bore section 48 where it passes through and around the spring 76 before entering the openings 90 in the deflector 78.After passing through deflector 78, the fluid enters passage 94 in outlet adapter 92 and then exits valve assembly 40 through the first orifice 102. Figure 4 illustrates the condition in which the fluid flow and pressure differential on opposite sides of piston 50 is not sufficient to overcome the guiding force of spring 76. In this condition, spring 76 guides washer 70 into engagement with the end face 47 of hole 48 in valve body 42. The discharge hole 46 is configured to allow flange 68 to be received and prevent the washer 70 from entering. In the illustrated embodiment, this is achieved using a circular washer 70 having a diameter larger than the cylindrical hole 46; however, other geometric shapes may also be employed. When the fluid is flowing in the direction indicated by the flow lines 106, a pressure differential between different points in the fluid path will exist and will generate forces acting on piston 50, primarily the pressure differential on each side of orifice 62 acting on the end wall 60, and will guide piston 50 to the position shown in Figure 4.At relatively low flow rates, the force acting on piston 50 generated by the pressure differential will be relatively low and will be unable to overcome the spring's guiding force 76. Figure 5 illustrates the assembly of valve 40 with the fluid flowing in the same direction as shown in Figure 4, but where the pressure differential on opposite sides of piston 50 is greater. In the condition illustrated in Figure 5, the force acting on piston 50 generated by the pressure differential is large enough to compress spring 76 and orient piston 50 towards deflector element 78. When piston 50 is oriented towards deflector 78, the annular opening 98 becomes progressively smaller and thus acts to restrict the flow of fluid through fluid passage 100. In general, a larger pressure differential would result in a higher flow rate through a given fluid passage. However, due to the variable constriction in fluid passage 100 defined by the variable opening 98, the opening 98 acts to constrict the flow of fluid through passage 100 and thus opposes the increased flow effects of an increasing pressure differential.At a sufficiently high pressure differential, the opening 98 can be completely closed with the tapered surface 66 engaging the end of the deflector 82. If the opening 98 is completely closed, a small amount of fluid can still pass through the drain fluid 88 and allow some fluid to be conducted through the fluid passage 100. Thus, the operable coupling of the spring 76 with the piston 50 provides a restriction, i.e., opening 98, which varies in response to the pressure differential of the fluid on opposite sides of the restriction and thus provides a fluid compensation mechanism that limits the fluid flow rate through the valve assembly 40 to a maximum value.The precise value of the maximum flow rate will be determined not only by the dimensions of the opening 62, the spring force of the spring 76 and the configuration of the variable opening 98, but also by the properties of the fluid flowing through the valve assembly, as will be recognized by those skilled in the art. Figure 6 illustrates the assembly of valve 40 with fluid flowing in a direction opposite to that shown in Figures 4 and 5, as indicated by the flow arrows 108 and sometimes referred to as the unregulated direction. When the fluid flows in the direction shown in Figure 6, if the piston Piston 50 is initially in the position shown in Figure 5, and will be guided by spring 76 to the position shown in Figure 4. In this position, an external radial part 73 of the coupling element 70 engages the end face 47 to limit the displacement of the coupling element, for example, washer 70. The piston 50 will then be guided to the position shown in Figure 6 due to the pressure differential and forces imparted to the piston 50 by the fluid impacting the piston 50, firstly at the end wall 60, when the fluid flows through the valve assembly 40. The displacement of the piston 50 will be interrupted at the position shown in Figure 6 due to the engagement of the flange 68 with the end face or shoulder 67 between the cylindrical passage sections 46 and 44. Thus, the piston 50 has a displacement length from a first position 50a represented in Figure 5 to a second position 50b represented in Figure 6 which has an oriented part and a non-oriented part. with regard to spring 76.The piston 50 also has a third position 50c, shown in Figure 5, between the first and second positions 50a, 50b. When the piston 50 is located between the first position 50a and the third position 50c, the spring 76 exerts a guiding force on the piston 50, impelling it in the direction of the third position 50c; thus, that part of the piston 50's displacement length between positions 50a and 50c is a guided portion. When the piston 50 is located between positions 50c and 50b, the piston 50 is not guided with respect to the spring 76. As described above, however, the piston 50 is guided by the fluid flow both towards and away from the deflector 78 when it is between positions 50c and 50b. When piston 50 is between positions 50a and 50c shown in Figures 5 and 4, respectively, the second orifice 104 is defined only by the measuring orifice 62, which has a fixed area for fluid communication through it. When piston 50 moves from position 50c to position 50b shown in Figure 6, the first end 56 of piston 50 is projected beyond the cylindrical section 43 of the valve body 42, exposing the openings 64 in the side wall 52. When the openings 64 are exposed, the area of ​​the second orifice 104 is effectively increased, improving the fluid outflow from the fluid passage 100. In the illustrated embodiment, the variable opening 98 is also increased when piston 50 moves from position 50c (Figure 4) to position 50b (Figure 6), increasing the space between the deflector end 82 and the piston end 58.It is not necessary for the opening 98 to vary in area when piston 50 is between positions 50c and 50b because valve assembly 40 is not performing a flow regulation function when the fluid flow positions piston 50 between 50c and 50b. However, the continued increase in opening 98, where opening 98 has its largest area when piston 50 is in position 50b, does not advantageously increase the fluid flow through valve assembly 40 in the reverse or unregulated direction shown in Figure 6. When the valve assembly is in the condition shown in Figure 6 and the fluid flow is reversed, the piston 50 will initially be in the position shown in Figure 6; however, since the piston 50 is not spring-oriented in this position, the piston 50 will move to the position shown in Figure 4 almost immediately upon reversal of the fluid flow due to the forces acting on the piston 50 caused by the fluid flow through the valve assembly 40, and the flow rate will not be subject to an irregular transition caused by the closing of the openings 64. Thus, by providing a piston 50 with a displacement length having a non-spring-oriented part 76, the fluid flow through the valve 40 in the direction shown in Figure 4 closes the openings 64 almost immediately and allows the hydraulic fluid flow rate to be smoothly regulated. It is also indicated that the efficient flow of fluid 10 through the valve assembly 40 is increased by the use of a large diameter spring that is located radially outward from the cylindrical side wall 52 of the piston 50. By providing a spring 76 having a diameter 77 that is larger than the diameter 51 of the piston 50 and locating the spring 76 outside the axial passage of the piston, the opening 62 in the end wall 60 can become larger because the end wall 60 should no longer engage the spring 76. The use of a larger measuring orifice 62 facilitates the efficient transport of fluid through the valve assembly 40 in both directions. By transporting the fluid more efficiently through the valve assembly 40, the fluid will experience less pressure loss and generate less heat when passing through the orifice 62 and valve assembly 40. Also seen in Figures 3-6 is an O-ring 110 located on the cylindrical section 43. The O-ring 110 is used to provide a seal between the valve body 42 and the structure to which the valve body 42 is attached. In a typical installation, the valve body 42 would be grooved into the bore of a cast iron valve body. Similarly, the O-ring 112 located on the adapter body 92 is used to provide a seal between the adapter body 112 and a fluid conduit or other fluid conveying structure. In a typical installation, the adapter body 92 would be placed in communication with a fluid conduit, for example, a hose or pipe, leading to a hydraulic motor. While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this description. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. C > .· · » ' · J . ' · J : O · _ * »4 .» · · JJ • ujt 9 9 0 9 t 9 -J ¢-.0^ 9--0 9 9 19^ · <_ 9 9 0 t « ·

Claims

CLAIMS 1. Valve assembly, CHARACTERIZED in that it comprises: a valve body defining a fluid passage extending through said valve body, said fluid passage having a first end and a second opposite end, said first end defining a first orifice through which the fluid is communicated with and from said fluid passage and said second end defining a second orifice through which the fluid is communicated with and from said fluid passage; a guiding element; a valve element movably disposed within said fluid passage within said valve body, said valve element having a displacement length extending from a first position relative to said valve body to a second position relative to said valve body,the said guiding element guiding the said valve element along the said 20 displacement length of the said first position in the direction of a third position disposed between the said first and second positions, the said valve element at least partially defining a first variable opening, a second opening and at least a third opening, the said first opening defining a variable constriction in the said fluid passage between the said first and second ends and having a size that progressively increases when the said valve element moves from the said first position to the said third position, the said second opening and the said at least one third opening defining the said second orifice wherein, when the said valve element is disposed between the said first position and the said third position, the said second orifice is defined only substantially by the said second opening and,when said valve element is in said second position, said second orifice is defined by said second opening and said at least one third opening; 10 wherein said valve element defines a valve element passage extending from said second orifice to said first opening, said guiding element being disposed outside said valve element passage; and 15 wherein the fluid flow, through said fluid passage within said valve body in a first direction from said second end to said first end, exerts pressure on said valve element and guides said valve element to said first position 20 and wherein the fluid flow, through said fluid passage within said valve body in a second direction from said first end to said second end,exerts pressure on said valve element and directs said valve element to said second position. 25 2. Valve assembly, according to claim 1, CHARACTERIZED in that said valve element is a substantially cylindrical piston.

3. Valve assembly, according to claim 2, CHARACTERIZED in that said piston includes an end wall disposed at a first axial end of said piston and a second substantially cylindrical side wall wherein said valve element passage is a passage extending axially through said piston defined by said side wall, said second opening communicating with said axial passage and being defined by said end wall, said first opening disposed near a second axial end of said piston opposite said first axial end,4. Valve assembly according to claim 3, characterized in that the piston is interchangeable within a substantially cylindrical bore defined in the valve body, the first axial end of the piston being disposed within the bore and substantially impeding fluid flow through the at least one third opening when the piston is disposed between the first and third positions, and in that the first axial end of the piston projects beyond the bore exposing the at least one third opening and permitting fluid flow through it when the piston is disposed in the second position.

5. Valve assembly according to claim 3,CHARACTERIZED in that said cylindrical side wall defines a first diameter and said guiding element is a helical spring defining a second diameter, said second diameter being larger than said first diameter.

6. Valve assembly, according to claim 1, CHARACTERIZED in that said displacement length of said valve element includes a guided displacement portion between said first and third positions in which said guiding element guides said valve element from said first position to said third position, and a non-guided displacement portion between said third position and said second position in which said valve element is non-guided with respect to said guiding element.

7. Valve assembly, according to claim 1,CHARACTERIZED in that the movement of said valve element from said third position to said second position increases the area of ​​said first opening.

8. Valve assembly, according to claim 1, CHARACTERIZED in that said second opening is a measuring orifice having a fixed area and in which the operable coupling of said guiding element and said valve element to define said variable first opening provides a pressure-compensated flow control mechanism whereby said valve assembly limits the fluid flow through said fluid passage in said first direction to a predefined maximum flow rate.

9. Valve assembly, CHARACTERIZED in that it comprises: a valve body defining a fluid passage extending through said valve body, said fluid passage having a first end and an opposite second end,The said first end defines a first orifice through which the fluid is communicated with and from said fluid passage, and the said second end defines a second orifice through which the fluid is communicated with and from said fluid passage; a guiding element; a valve element movably disposed within said fluid passage within said valve body and having a displacement length extending from a first position relative to said valve body to a second position relative to said valve body, said valve element further defining a third position along said displacement length, said third position disposed between said first and second positions, said valve element defining at least partially a first variable opening and said second orifice.The said first opening defines a variable constriction in the said fluid passage between the said first and second ends and having a dimension that progressively increases when the said valve element moves from the said first position to the said third position, the said second orifice being variably dimensioned in that the said second orifice defines a first area providing fluid communication with the said fluid passage when the said valve element is in the said third position and defines a second area providing fluid communication with the said fluid passage when the said valve element is in the said second position,the said second area being larger than the said first area; the said displacement length including a portion of oriented displacement between the said first and third positions wherein the said guiding element guides the said valve element from the said first position to the said third position and a portion of non-oriented displacement between the said third position and the said second position wherein the said valve element is non-oriented with respect to the said guiding element; and wherein the fluid flow through the said fluid passage, in a first direction from the said second end to the said first end exerts pressure on the said valve element and guides the said valve element to the said first position and wherein the fluid flow through the said fluid passage,in a second direction from said first end to said second end, it exerts pressure on said valve element and directs said valve element to said second position.

10. Valve assembly, according to claim 9, CHARACTERIZED in that said second orifice is defined by a second opening having a fixed area and at least one third opening, said second orifice being defined by said second opening when said valve element is between said first and third positions and said second orifice being defined by said second opening and said at least one third opening when said valve element is in said second position.

11. Valve assembly, according to claim 9, CHARACTERIZED in that said valve element is a substantially cylindrical piston.

12. Valve assembly, according to claim 11,CHARACTERIZED in that said piston includes a substantially cylindrical side wall defining a passage extending axially through said piston and a terminal wall disposed at a first axial end of said piston, said second orifice including a second opening defined by said terminal wall and communicating with said axial passage and at least a third opening defined by said side wall and disposed near said first axial end of said piston, said opening disposed near a second axial end of said piston opposite said first axial end.

13. Valve assembly, according to claim 12, CHARACTERIZED in that said piston is interchangeable within a substantially cylindrical bore defined in said valve body,The first axial end of said piston being disposed within said bore and substantially impeding the flow of fluid through said at least a third opening when said piston is disposed between said first and third positions, and wherein said first axial end of said piston projects beyond said bore exposing said at least a third opening and permitting the flow of fluid through it when said piston is disposed in said second position.

14. Valve assembly according to claim 12, CHARACTERIZED in that said cylindrical side wall defines a first diameter and said guiding element is a helical spring defining a second diameter, said second diameter being larger than said first diameter.

15. Valve assembly according to claim 14, CHARACTERIZED in that it further comprises a coupling element operably disposed between said spring and said piston,the said coupling element operably engages with said piston and transfers a guiding force from said spring to said piston when said piston is disposed between said first and third positions and wherein the movement of said piston from said third position to said second position operably disengages said coupling element and said piston.

16. Valve assembly, according to claim 9, CHARACTERIZED in that said second orifice includes a measuring orifice having a fixed area defining said first area and wherein the operable coupling of said guiding element and said valve element to define said first variable opening provides a pressure-compensated flow control mechanism whereby said valve assembly limits the fluid flow through said fluid passage in said first direction to a predefined maximum flow rate.

17. Valve assembly,according to claim 1, CHARACTERIZED in that the movement of said valve element from said third position to said second position increases the area of ​​said first opening.

18. Valve assembly, CHARACTERIZED in that it comprises: 10 a valve body defining a fluid passage extending through said valve body, said fluid passage having a first end and a second opposite end, said first end defining a first orifice through which fluid is communicated to and from said fluid passage and said second end defining a second orifice through which fluid is communicated to and from said fluid passage; a spring disposed within said fluid passage and engageable with said valve body; 20 a piston is movably disposed within said fluid passage and is operably coupled with said spring,the said piston having a displacement length extending from a first position in said fluid passage to a second position in said fluid passage, said piston further defining a third position along said displacement length, said third position disposed between said first and second positions, said piston having a substantially cylindrical side wall defining a passage extending axially through said piston and an end wall disposed at a first axial end of said piston, said piston defining at least partially a first opening, a second opening and at least a third opening, said first opening being in communication with said axial piston passage and disposed at a second axial end of said piston opposite said first axial end,the said first opening defining a variable constriction in the said fluid passage between the said first and second ends and having a dimension that progressively increases when the said piston moves from the said first position to the said third position, the said end wall of the said piston defining the said second opening in communication with the said axial piston passage, the said side wall of the piston defining at least one third position close to the said end wall wherein, when the said piston is disposed between the said first and third positions, the said second orifice is defined only substantially by, 2.0 said second opening and, when said piston is in said second position, said second orifice is defined by said second opening and said at least one third opening; wherein said spring is disposed outside said axial piston passage; and wherein the flow of fluid through said fluid passage in a first direction from said second end to said first end exerts pressure on said piston and orients said piston to said first position, and wherein the flow of fluid through said fluid passage in a second direction from said first end to said second end exerts pressure on said piston and orients said piston to said second position. 19.Valve assembly according to claim 18, characterized in that said piston is interchangeable within a substantially cylindrical bore defined in said valve body, said first axial end of said piston being disposed within said bore and substantially impeding the flow of fluid through said at least a third opening when said piston is disposed between said first and third positions, and said first axial end of said piston projects beyond said bore exposing said at least a third opening and permitting the flow of fluid through it when said piston is disposed in said second position.

20. Valve assembly according to claim 18, characterized in that said cylindrical side wall defines a first diameter and said guiding element is a helical spring defining a second diameter, said second diameter being larger than said first diameter.

21. Valve assembly, according to claim 20, CHARACTERIZED in that said piston includes a flange extending radially outwards operably coupled with said spring. 22.Valve assembly, according to claim 21, CHARACTERIZED in that it further comprises a coupling element operably disposed between said spring and said flange, said coupling element having an outer perimeter radially disposed outward from said flange, said coupling element operably engaging with said flange and transferring a guiding force from said spring to said flange when said piston is between said first and third positions, a radially external part of said coupling element engaging said valve body when said piston is in said third position and the movement of said piston from said third position to said second position operably disengaging said coupling element and said flange. 23.

23. Valve assembly according to claim 22, characterized in that said flange is received in a discharge hole having a configuration that prevents the entry of said coupling element to disengage said coupling element and said flange.

24. Valve assembly according to claim 18, characterized in that the movement of said piston from said third position to said second position increases the area of ​​said first opening.

25. Valve assembly according to claim 18, characterized in that said displacement length of said piston includes an oriented displacement portion between said first and second positions where said spring orients said piston from said first position to said third position and a non-oriented displacement portion between said third position and said second position where said piston is non-oriented with respect to said spring. 5.

26. Valve assembly according to claim 18, characterized in that said second opening is a measuring orifice having a fixed area and said valve assembly further comprises a deflector element disposed within said fluid passage wherein said 10. The first variable opening is defined between said deflector element and said piston, and the operable coupling of said spring and piston provides a compensated flow control mechanism whereby said valve assembly limits the fluid flow through said fluid passage in said first direction to a predefined maximum flow rate.

27. Valve assembly according to claim 26, CHARACTERIZED in that the fluid flow through said fluid passage in said second direction is substantially unregulated by said valve assembly. 18 15' 26 32 28 Fig. 1) (Previous technique)