valve

Abstract

The valve (19.1) includes a flow passage connecting the housing inlet (42) and outlet (44), a valve seat (48) disposed within the flow passage, a closure member (50) displaceable between closed and open positions, and a throttling element (52) displaceable with the closure member. The throttling element has a forward portion (70) of increasing cross-sectional area, a frusto-conical rear portion (72) and an intermediate portion (74) of sufficient length such that the intermediate portion enters the guide portion (49) of the flow passage before the seal (56) contacts the valve seat. The throttling element is configured to progressively reduce the effective cross-sectional area of ​​the flow passage as the closure member is displaced from the open position toward the closed position.

Description

[Technical field]

[0001] The present invention relates to a valve and a method for operating the valve. More specifically, it relates to a valve and a pressure exchange chamber ("PEC") pump system using the valve. It further relates to a PEC pump system kit and a valve closure unit. [Background technology]

[0002] Sometimes, when valves are used to regulate the flow of media, particularly when a fast-flowing fluid needs to be stopped quickly, significant shock loads can be experienced when the valve is closed. Under certain circumstances, these shock loads can be so significant that they can compromise the integrity of the system of which the valve forms a part.

[0003] One application where this could potentially occur is in a PEC pump system. A PEC pump system typically comprises one or more pipes, each having a media or pump-fluid valve arrangement at one end and a drive-fluid valve arrangement at the other end. The combination of each pipe and its associated valves constitutes a PEC.

[0004] Operating a PEC involves rapidly changing the pressure inside the PEC, which means that traditional means of preventing shock loads (also known as water hammer), such as gas shock absorbers, cannot be used.

[0005] For example, shock loads can occur within a PEC when media is drained therefrom and the media outlet and drive fluid inlet valves close before the media inlet and drive fluid outlet valves open to fill the PEC. Due to the high flow velocity of the drive fluid, the closure of the drive fluid inlet valve (which stops the fluid flow) can result in a substantial hydraulic shock or pressure surge with potentially damaging consequences.

[0006] There are many other applications in which valves are used to stop fast flowing fluids where this problem could potentially occur.

[0007] Among the aims of embodiments of the present invention is to provide means by which this problem may at least be ameliorated, or to provide a useful alternative. Summary of the Invention

[0008] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0009] In this application, sequence numbers (first, second, third, etc.) are arbitrarily assigned and used to distinguish parts herein, but do not indicate a particular order, sequence, or importance. Features described as optional with respect to one aspect are intended to be applicable as optional to all other aspects, where possible.

[0010] According to a first aspect of the invention, there is provided a valve comprising a housing, an inlet leading into the housing, an outlet leading from the housing at a location spaced from the inlet, a flow passage connecting in fluid communication the inlet and the outlet, a valve seat positioned within the flow passage and comprising a frusto-conical portion having a wide end and a narrow end spaced apart in a longitudinal direction, a guide portion extending coaxially away from the narrow end of the frusto-conical portion, a closure member displaceable between a closed position preventing flow of a medium through the flow passage and an open position allowing flow of a medium through the flow passage, and a throttle element displaceable together with the closure member, the throttle element being inserted into the guide portion when the closure member is displaced towards its closed position, A valve is provided that comprises a throttling element including: (i) a forward portion having a cross-sectional area that increases for at least a portion of its length away from the tip of the throttling element; (ii) a frusto-conical rear portion complementary to the valve seat; and (iii) an intermediate portion extending between the forward and rear portions and having a sufficient length such that the intermediate portion enters a guide portion of the flow passage before the seal contacts the valve seat, thereby adjusting the effective cross-sectional area of ​​the flow passage as the closure member is displaced from its open position toward its closed position and reducing impact loads by progressively reducing the cross-sectional area of ​​the flow passage.

[0011] The valve closure member optionally includes an elastomeric seal having a frusto-conical sealing surface that sealingly abuts against the valve seat in the closed position.

[0012] The guide portion may define a circular cross-section, an elliptical cross-section, a polygonal cross-section, or any other convenient shape.

[0013] The valve may comprise an actuated valve and may include an actuator for displacing the closure member between its open and closed positions.

[0014] The valve seat may be annular and may be disposed about the flow passage such that the flow passage extends (or passes) therethrough.

[0015] The valve seat may comprise a surface of the housing that may be hardened (eg, by coating or infiltrating with a hard material) or an insert.

[0016] The throttling element preferably extends through the valve seat and into a portion of the flow passage adjacent it, thereby gradually reducing the area between the sides of the flow passage and the throttling element, effectively reducing the cross-sectional area of ​​the flow passage.

[0017] The seal may be fixed to and displaceable with the throttling element, the seal being positioned adjacent to and projecting radially beyond the rear portion of the throttling element such that a sealing surface of the seal contacts the valve seat before the rear portion of the throttling element. The seal may comprise an elastomeric material.

[0018] The dimensions of the closure member may be selected to achieve a desired throttle profile. In one embodiment, the intermediate portion of the closure member has a diameter 0.5 to 1 mm less than the diameter of the guide portion of the flow passage.

[0019] The guide portion may have a cylindrical shape. Alternatively, the guide portion may have a different shape.

[0020] According to a second aspect of the present invention, there is provided a PEC pump system comprising at least one PEC having a medium valve arrangement at one end thereof and a drive fluid valve arrangement at an opposite end thereof, at least one of the valve arrangements including at least one valve of the type described above.

[0021] In a preferred embodiment, at least the drive fluid inlet valve of the drive fluid valve arrangement is a valve of the type described above.Optionally, the drive fluid outlet valve of the drive fluid valve arrangement is a valve of the type described above.

[0022] The PEC pump system may include a plurality of PECs arranged in parallel and a feeder including a feeder pump having a suction side and a discharge side connected in flow communication with a media inlet valve.

[0023] The components of the PEC pump system may be shipped disassembled or in prefabricated kit form for assembly on-site.

[0024] Thus, according to a third aspect of the present invention, there is provided a PEC pump system kit comprising parts of the second aspect.

[0025] According to a fourth aspect of the present invention, there is provided a method of reducing shock loads in a flow path for a medium in a pressure pump system, the method comprising: (i) reducing an effective cross-sectional area of ​​the flow path to throttle the medium flow; (ii) substantially closing the flow path after reducing its effective cross-sectional area; and (iii) sealing the flow path with an elastomer only after substantially closing the flow path.

[0026] The method may be carried out using a profiled valve body and housing.

[0027] Reducing the effective cross-sectional area of ​​the flow passage to throttle the media flow may be performed by inserting a forward portion of a throttle element into a portion of the flow passage. The throttle element may have a leading edge and a trailing edge, the leading edge having an increasing cross-sectional area extending from the leading edge to the trailing edge over at least a portion of its length.

[0028] The step of substantially closing the flow passage after reducing its effective cross-sectional area may be performed by inserting an intermediate portion of the throttling element into the lower portion of the flow passage, the intermediate portion being only slightly smaller than the diameter of the lower portion of the flow passage.

[0029] The intermediate portion may extend between the anterior portion and the posterior portion.

[0030] The step of sealing the flow passage with an elastomer only after substantially closing the flow passage may be performed using an elastomeric seal mounted above and projecting laterally beyond a complementary frusto-conical rear portion of the valve seat. The lateral projection may comprise a radial projection.

[0031] By virtue of this embodiment, the throttling function is separated from and precedes the sealing function.

[0032] According to a fifth aspect of the present invention there is provided a valve closure unit for use in a valve of the type described above having a hollow housing defining a first opening, a second opening spaced from the first opening, a flow passage connecting the first and second openings in flow communication, and a valve seat provided in the flow passage, the closure unit including a closure member configured to sealingly seat against the valve seat, and a throttling element having a leading end and a trailing end, the leading end of the throttling element having a smaller cross-sectional area than the trailing end, the throttling element being displaceable together with the closure member such that as the closure member is displaced towards its closed position the throttling element extends through the valve seat and into a portion of the flow passage adjacent thereto, thereby progressively reducing the area between a side of the flow passage and the throttling element, effectively progressively reducing the cross-sectional area of ​​the flow passage.

[0033] According to a sixth aspect of the present invention, there is provided a valve comprising: a housing; an inlet leading into the housing; an outlet leading from the housing at a location spaced from the inlet; a flow passage connecting in flow communication the inlet and the outlet, the flow passage including a frusto-conical portion having a wide end and a narrow end spaced longitudinally therefrom, and a cylindrical portion extending coaxially away from the narrow end of the frusto-conical portion; a valve seat positioned within the flow passage and comprising the frusto-conical portion; a closure member displaceable between a closed position in which it seats against the valve seat to prevent flow of a medium through the flow passage and an open position in which it allows flow of a medium through the flow passage, the closure member including an elastomeric seal having a frusto-conical sealing surface that sealingly abuts against the valve seat in the closed position; and a throttling element having a leading end and a trailing end, the leading end of the throttling element having a smaller cross-sectional area than the trailing end, the throttling element being configured to be operable to selectively move the closure member between the closed position and the open position. and a throttling element displaceable with the member and inserted into the cylindrical portion as the closure member is displaced toward its closed position, the throttling element including: (i) a forward portion having a cross-sectional area that increases for at least a portion of the length of the throttling element away from the tip; (ii) a rear portion that is frusto-conical in shape and complementary to the valve seat; and (iii) an intermediate portion extending between the forward and rear portions, the intermediate portion being cylindrical in shape and the length of the intermediate portion of the throttling element being sufficiently long such that it enters the cylindrical portion of the flow passage before the seal contacts a surface of the valve seat, thereby adjusting the effective cross-sectional area of ​​the flow passage as the closure member is displaced from its open position toward its closed position and reducing impact loads by progressively reducing the area between the side of the flow passage and the throttling element, effectively reducing the cross-sectional area of ​​the flow passage. [Brief description of the drawings]

[0034] These and other aspects of the invention will now be described, by way of example, with reference to the accompanying schematic drawings.

[0035] [Figure 1] FIG. 1 shows a schematic diagram of a PEC pump system according to an embodiment of the present invention. [Diagram 2]FIG. 2 shows an axial cross-sectional view of a portion of a valve according to another embodiment of the invention, the valve forming part of the PEC pump system of FIG. [Diagram 3] 3 to 7 show cross-sectional views of the valve of FIG. 2, illustrating sequential displacement of the closure member of the valve from a partially open position, as shown in FIG. 2 of the drawings, to its closed position, as shown in FIG. 7 of the drawings. [Figure 4] 3 to 7 show cross-sectional views of the valve of FIG. 2, illustrating sequential displacement of the closure member of the valve from a partially open position, as shown in FIG. 2 of the drawings, to its closed position, as shown in FIG. 7 of the drawings. [Diagram 5] 3 to 7 show cross-sectional views of the valve of FIG. 2, illustrating sequential displacement of the closure member of the valve from a partially open position, as shown in FIG. 2 of the drawings, to its closed position, as shown in FIG. 7 of the drawings. [Figure 6] 3 to 7 show cross-sectional views of the valve of FIG. 2, illustrating sequential displacement of the closure member of the valve from a partially open position, as shown in FIG. 2 of the drawings, to its closed position, as shown in FIG. 7 of the drawings. [Figure 7] 3 to 7 show cross-sectional views of the valve of FIG. 2, illustrating sequential displacement of the closure member of the valve from a partially open position, as shown in FIG. 2 of the drawings, to its closed position, as shown in FIG. 7 of the drawings. [Figure 8] FIG. 8 shows a three-dimensional view of a portion of the closure member of the valve of FIG. [Figure 9] FIG. 9 illustrates a side view of a portion of the closure member shown in FIG. [Figure 10] FIG. 10 shows, on an enlarged scale, a portion of the valve of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] In FIG. 1 of the drawings, reference numeral 10 generally refers to a portion of a PEC pump system according to an embodiment of the present invention.

[0037] The PEC pump system 10 includes three (PECs) 11.1, 11.2, 11.3 each defined by a fluid container which in this embodiment includes lengths of pipe 12, 14, 16 having media or pump fluid valve arrangements 18, 20, 22 respectively connected to one end thereof and drive fluid valve arrangements 19, 21, 23 respectively connected to the opposite end thereof. In this embodiment, the pipes 12, 14, 16 extend longitudinally, although other configurations are possible.

[0038] Each medium valve arrangement 18, 20, 22 comprises a medium inlet valve 18.1, 20.1, 22.1 by which the medium to be pumped can be admitted to the associated pipe 12, 14, 16 and a medium outlet valve 18.2, 20.2, 22.2 by which the pumped medium can be discharged from the pipe 12, 14, 16 along a discharge pipe (or riser) 24. Similarly, each drive fluid valve arrangement 19, 21, 23 comprises an inlet valve 19.1, 21.1, 23.1 according to an embodiment of the invention by which high pressure drive fluid can be admitted to the associated pipe, and an outlet valve 19.2, 21.2, 23.2 by which the drive fluid can be discharged from the associated pipe.

[0039] The PEC pump system 10 further comprises a feed arrangement, a part of which is generally indicated by the reference numeral 26, configured to feed the pumped medium to the medium inlet valves 18.1, 20.1, 22.1. The feed arrangement 26 comprises a feed or delivery pump (not shown) having a suction side and a discharge side. The feeder pump is typically a centrifugal pump. The feed arrangement 26 further comprises a pipe 32 connected to a source of the medium and three feed lines 35, 36, 37, each of the feed lines having an upstream end and a downstream end connected to the pipe 32. The downstream ends of the feed lines 35, 36, 37 are connected to the medium inlet valves 18.1, 20.1, 22.1, respectively. In use, the pumped medium is transported through the pipe 32 and the feed lines 35, 36, 37 to the medium inlet valves 18.1, 20.1, 22.1.

[0040] In use, the media inlet valves 18.1, 20.1, 22, 1 are open and the corresponding drive fluid outlet valves 19.2, 21.2, 23.2 are open, allowing media to enter the associated pipes 12, 14, 16 and displace the drive fluid out of the pipes through the associated drive fluid outlet valves 19.2, 21.2, 23.2. When the desired amount of media has entered the pipes, the media inlet valves and drive fluid outlet valves are closed. The media outlet valves 18.2, 20.2, 22.2 and drive fluid inlet valves 19.1, 21.1, 23.1 are opened to allow high pressure drive fluid to enter the pipes and displace the media out of the pipes through the media outlet valves 18.2, 20.2, 22.2 and into the discharge pipe 24.

[0041] Once the medium has been discharged from the pipe, the associated medium outlet valve and drive fluid inlet valve close and the medium inlet valve and drive fluid outlet valve open to fill the pipe with medium again in the manner described above.

[0042] To allow for near continuous pumping, the operation of the valves of the different PECs 11.1, 11.2, 11.3 are staggered such that the filling and emptying of the PECs 11.1, 11.2, 11.3 with media occurs nearly continuously.

[0043] Each of the actuation fluid inlet valves 19.1, 21.1, 23.1 are substantially identical. For simplicity of explanation, only the actuation fluid inlet valve 19.1 is described in detail below. In one embodiment of the present invention, the actuation fluid outlet valves 19.2, 21.2, 23.2 are of similar construction to the actuation fluid inlet valves 19.1, 21.1, 23.1, and therefore the following description of valve 19.1 also applies to valves 19.2, 21.2, 23.2.

[0044] 2-10 of the drawings, valve 19.1 includes a housing, a portion of which is shown in the drawings and generally indicated by reference numeral 40. An inlet 42 leads into housing 40 and an outlet 44 leads from housing 40 at a location spaced from the inlet and flow paths, a major portion of which is generally indicated by dashed arrow 46, extending through housing 40 and connecting inlet 42 and outlet 44 in flow communication, as will be explained in more detail below. Arrow 46 indicates unidirectional flow, in other embodiments flow may be in the opposite direction to that indicated by arrow 46.

[0045] Valve 19.1 further includes a valve seat, generally indicated by reference numeral 48, positioned between inlet 42 and outlet 44, and a closure member, generally indicated by reference numeral 50, displaceable between a closed position (shown in FIG. 7 of the drawings) in which it blocks the flow of medium through flow path 46, and an open position in which inlet 42 and outlet 44 are connected in flow communication to permit the flow of medium through flow path 46. In one embodiment of the invention, valve seat 48 may be formed by a hardened surface within housing 40. In another embodiment shown in the drawings, valve seat 48 is formed by an insert 51 that facilitates replacement of a worn valve seat 48.

[0046] Valve 19.1 further includes a throttling device, generally indicated by reference numeral 52, which is configured to reduce the effective cross-sectional area of ​​flow path 46 as closure member 50 is displaced from its open position towards its closed position, as will be explained in more detail below. When closure member 50 is closed, another flow path in another valve is open such that the flow rate of medium through valve 19.1 is reduced without causing any (or any significant) water hammer effect.

[0047] The housing insert 51 defines two portions of the flow passage 46. The first portion is defined by the annular valve seat 48, which is frusto-conical in shape (extending from narrow end 48.1 to wide end 48.2, best seen in FIG. 2), and the second portion of the flow passage 46 defined by the housing insert 51 is the guide portion 49, which in this embodiment is cylindrical in shape and of the same diameter, extending away from the narrow end 48.1 of the valve seat 48. In this embodiment, the guide portion 49 is located at the bottom of the flow passage 46.

[0048] The closure member 50 includes an annular seal 56 having a frusto-conical sealing surface 58 that is complementary in shape to a surface of the valve seat 48. In this embodiment, the annular seal 56 comprises an elastomeric material.

[0049] The throttle device 52 includes a throttle element, generally indicated by the reference numeral 60. The seal 56 is sandwiched between the throttle element 60 and an annular retaining member 62. An axially extending stud bolt 64 extends through the retaining member 62 and the throttle element 60, and a nut (or other fastening element) is mounted on an end portion of the stud bolt 64 to urge the throttle element 60 and the retaining member 62 toward one another, thereby fixing the seal 56 in place. The throttle element 60, seal 56, and retaining member 62 together form a valve closure unit, generally indicated by the reference numeral 65.

[0050] The stud bolt 64 is typically connected to an actuator, such as a hydraulically actuated piston and cylinder arrangement (not shown), whereby the valve closure unit 65 is displaceable between an open position in which the seal 56 is spaced from the valve seat 48 and a closed position in which the seal surface 58 abuts the valve seat 48.

[0051] In this embodiment, the closure member 50 and the throttle element 60 comprise two parts of a single component, although in other embodiments separate components that are interconnected may be provided.

[0052] The throttling element 60 has a leading end 66 and a trailing end 68 .

[0053] The throttle element 60 includes a forward portion 70 (best seen in Figures 8 and 9), the diameter and therefore the cross-sectional area of ​​which increases away from the tip 66 for a portion of the length of the throttle element 60. In addition, the throttle element 60 includes a rearward portion 72 that is frusto-conical in shape, the diameter of which decreases away from the rear end 68 of the throttle element 60. The throttle element 60 includes an intermediate portion 74 that is cylindrical in shape (in this embodiment, although in other embodiments it may have a different shape) and extends between the forward and rearward portions 70, 72. The rearward portion 72 is of a shape complementary to the valve seat 48. In particular, the angle of the rearward portion 72 is selected to ensure that there is a large contact area with the seat 48 (at least prior to any wear of the rearward portion 72 or the seat 48) when the valve closure unit 65 is in the closed position.

[0054] In use, when the closure member 50 is in its open or partially open position (as shown in FIG. 2 of the drawings), the throttling element 60 contacts the valve seat 48, allowing an almost unlimited flow through the flow passage 46 between the inlet 42 and the outlet 44. However, when the closure member 50 is displaced towards its closed position, the front part 70 of the throttling element 60 enters the guide part 49 of the flow passage 46, effectively reducing the cross-sectional area of ​​the flow passage 46 and restricting the flow of the medium through the flow passage 46. As the closure member 50 advances towards its closed position, the throttling element 60 is inserted further and further into the guide part 49, and thanks to the increasing diameter of the front part 70 of the throttling element 60, the annular space between the throttling element 60 and the guide part 49 is progressively reduced, thereby reducing the effective cross-sectional area of ​​the flow passage 46 and therefore the flow rate of the medium through the valve 19.1. Thus, the throttling element 60 and the guide part 49 together form the throttling device 52.

[0055] As can best be seen in Figure 10 of the drawings, the seal 56 protrudes radially beyond the frusto-conical surface of the rear portion 72 of the throttling element 60 such that the seal surface 58 contacts the surface of the valve seat 48 in front of the throttling element 60 as the closure member 50 approaches its closed position. As indicated in Figure 10 by the letter G, the extent to which the seal protrudes beyond the frusto-conical surface of the throttling element is limited to approximately 1-4 mm to reduce the risk of protrusion of the seal 56 between the opposing surface of the throttling element 60 and the valve seat 48.

[0056] The cylindrical intermediate portion 74 of the throttling element 60 has a diameter that is only slightly smaller, for example on the order of 0.5-1 mm smaller, than the diameter of the cylindrical portion 49 of the flow passage so that maximum throttling occurs as the intermediate portion 74 enters the cylindrical portion 49 of the flow passage.

[0057] The rate at which the flow rate of the medium is reduced can also be controlled by adjusting the rate at which the closure member is displaced towards its closed position and / or by varying the shape of the throttling element 60 .

[0058] The particular dimensions of the valve are selected to obtain desired performance characteristics. Thus, by way of example, in the embodiment shown, the guide portion 49 has a diameter E of 74 mm. The tip 66 of the forward portion 70 has a diameter A of 70 mm. The diameter B of the intermediate portion is typically 0.5-1 mm less than E, i.e., 73-73.5 mm. The forward portion 70 has a length C of 40 mm. The intermediate portion has a length D of 10 mm. Naturally, the size of the valve may vary depending on the intended application.

[0059] By gradually reducing the cross-sectional area of ​​the flow passage 46 before the closure member 50 reaches its closed position, the risk of hydraulic shock in high flow applications is prevented.

[0060] By including a cylindrical portion 74, which is only slightly narrower than the guide portion 49 and extends axially, there is a defined length throughout which the cross-sectional area remains constant. This ensures that when the valve 19.1 is closed, there is a constant minimum cross-sectional area just prior to closing and sealing.

[0061] Although the valve described is a drive fluid inlet valve, it will be appreciated that the valve can be used in any other application, for example as a drive fluid outlet valve. Furthermore, in other applications the direction of flow of the medium through the valve can be reversed, in which case the inlet and outlet are reversed.

[0062] In other embodiments, the guide portion 49 may have a different shape than that described above. In other embodiments, the housing insert 51 may be an integral part of the housing 40 rather than a separate part and may be contained within the housing 40.

[0063] First, it will be appreciated that a PEC pump system may be constructed in accordance with an embodiment of the present invention, the components of which may be shipped prefabricated or in kit form for assembly on-site.

[0064] Alternatively, an existing PEC pump system can be modified by replacing one or more of the valves with a valve according to an embodiment of the present invention. [Explanation of symbols]

[0065] Pressure Exchange Chamber (PEC) Pump System 10 PEC 11.1, 11.2, 11.3 Pipes 12, 14, 16 Media valve device 18, 20, 22 Media inlet valve 18.1, 20.1, 22.1 Media outlet valve 18.2, 20.2, 22.2 Driving fluid valve device 19, 21, 23 Drive fluid inlet valve 19.1, 21.1, 23.1 Drive fluid outlet valve 19.2, 21.2, 23.2 Exhaust pipe 24 Feeding device 26 Pipe 32 Supply lines 35, 36, 37 Housing 40 entrance 42 exit 44 Flow path 46 Valve seat 48 Narrow end of valve seat 48.1 Guide (cylindrical) part 49 Closure 50 Housing Insert 51 Squeezing device 52 Seal 56 Seal Surface 58 Aperture elements 60 Retaining member 62 Stud bolt 64 Valve Closure Unit 65 Tip 66 rear end 68 Front part 70 rear part 72 middle part 74 A Diameter of tip 66 B Diameter of middle section 74 C Length of front part 70 D Length of middle section 74 E Diameter of guide part 49 G Seal protrusion

Claims

1. A valve, Housing and an inlet leading into the housing; an outlet communicating with the housing at a location spaced from the inlet; a flow path connecting in fluid communication the inlet and the outlet; a valve seat positioned within the flow passage, the valve seat comprising a frusto-conical portion having a wide end and a narrow end spaced apart longitudinally; a guide portion extending coaxially away from the narrow end of the frusto-conical portion; a closure member displaceable between a closed position preventing flow of medium through the flow passage and an open position allowing flow of medium through the flow passage; a throttle element displaceable together with the closure member, the throttle element being inserted into the guide portion when the closure member is displaced towards its closed position, the throttle element comprising: (i) a forward portion, the cross-sectional area of ​​which increases for at least a portion of its length away from the tip of the throttling element; (ii) a frusto-conical rear portion complementary to the valve seat; and (iii) a throttling element including an intermediate portion extending between the forward portion and the aft portion, the intermediate portion having a sufficient length such that the intermediate portion enters the guide portion of the flow passage before a seal contacts the valve seat; a valve whereby as the closure member is displaced from its open position towards its closed position, the effective cross-sectional area of ​​the flow passage is adjusted and impact loads are reduced by progressively reducing the cross-sectional area of ​​the flow passage.

2. 2. The valve of claim 1, wherein the closure member includes an elastomeric seal having a frusto-conical sealing surface that sealingly abuts against the valve seat in the closed position, the seal positioned adjacent to and projecting radially beyond the rearward portion of the throttling element such that a surface of the seal contacts the valve seat prior to the rearward portion of the throttling element.

3. The valve of claim 1 or 2, wherein the guide portion defines a circular cross-section.

4. A valve as claimed in any one of the preceding claims, wherein the intermediate portion of the closure member has a diameter 0.5 to 1 mm smaller than a diameter of the guide portion of the flow passage.

5. A pressure exchange chamber pump system comprising at least one pressure exchange chamber having a medium valve arrangement at one end and a drive fluid valve arrangement at its opposite end, at least one of said valve arrangements comprising at least one valve according to any one of claims 1 to 4.

6. A pressure exchange chamber pump system according to claim 5, wherein at least the drive fluid inlet valve of the drive fluid valve device is a valve according to any one of claims 1 to 4.

7. 7. A pressure exchange chamber pump system according to claim 5 or 6, comprising a plurality of pressure exchange chambers arranged in parallel.

8. 1. A method for reducing shock loads in a flow path for a medium in a pressurizing pump system, the method comprising: (i) reducing an effective cross-sectional area of ​​the flow path to restrict the medium flow; (ii) substantially closing the flow passage after reducing the effective cross-sectional area thereof; and (iii) sealing the flow passage with an elastomer only after the flow passage is substantially closed.

9. 9. The method according to claim 8, wherein the step of reducing the effective cross-sectional area of ​​the flow passage to throttle the medium flow is performed by inserting a front portion of a throttle element into a portion of the flow passage.

10. 10. The method of claim 9, wherein the step of substantially closing the flow passage after reducing its effective cross-sectional area is performed by inserting an intermediate portion of the throttling element into a lower portion of the flow passage, the intermediate portion being slightly smaller than a diameter of the lower portion of the flow passage.

11. 11. The method according to any one of claims 8 to 10, wherein sealing the flow passage with an elastic body only after substantially closing the flow passage is performed using an elastic seal mounted above and projecting radially from a rear portion of a frusto-conical shape complementary to the valve seat.

Images