Liquid inlet conical valve

Abstract

The invention relates to a conical liquid inlet valve, in particular for a cryogenic fluid pump, comprising a valve (2) having a body provided with a frustoconical head (12) and a frustoconical seat (3) mated with the head (12), the valve (2) and the seat (3) being relatively movable between a closed configuration in which the head (2) cooperates in a sealed manner with the seat (3) to prevent the passage of fluid and an open configuration in which the head (2) is spaced from the seat (3) to allow the passage of fluid, the frustoconical surface of the head (12) comprising at least one irregularity (22) forming a rib and / or a groove configured to generate turbulence within the fluid flowing between the head (2) and the seat (3). Abstract figure: Fig. 1

Description

Title of the invention: Conical liquid inlet valve

[0001] The invention relates to a conical liquid inlet valve.

[0002] The invention relates more particularly to a conical intake valve of liquid, in particular for a cryogenic fluid pump, comprising a valve having a body provided with a frustoconical head and a frustoconical seat mated with the head, the valve and the seat being relatively movable between a closed configuration in which the head cooperates in a sealed manner with the seat to prevent the passage of fluid and an open configuration in which the head is spaced from the seat to allow the passage of fluid.

[0003] Generally speaking, an inlet flap or valve is movable between two open and closed positions. In the closed position, the valve must ensure a good seal. In the open, or passing, position, the valve must have minimal influence on the pressure drop of the fluid admitted to pass.

[0004] In the context of pressurization machines (compressor or pump), working at high pressures of up to several hundred bars, an inlet valve is commonly used to admit the fluid into the compression chamber. This is called an inlet valve. A fairly commonly used architecture is the so-called "conical" valve, which offers a good contact surface and good pressure resistance (see [Fig. 1]).

[0005] The invention applies in particular to a so-called "free" valve which is not controlled and whose opening and closing are caused by the pressure differentials between upstream and downstream.

[0006] For cryogenic pumps, the performance of the inlet valve in the forward direction is particularly important. Indeed, too great a pressure drop at the valve can potentially cause a sudden evaporation phenomenon, or "flash", which occurs when the pressure becomes equal to the saturation pressure of the fluid, leading to a drop in mass efficiency because less fluid is then transferred.

[0007] The risk of flash vaporization is particularly significant at the most significant sectional narrowing of the valve architecture, i.e. at the end of the truncated cone portion having the smallest diameter. At this location (sometimes called the "neck"), the fluid velocity approaches the critical regime and the pressure decreases below the saturation pressure. Proper sizing of the neck and the valve lift generally makes it possible to reduce this risk. In the divergent conical zone downstream (in the direction of the widening of the truncated cone portion), a significant depression can be established between the valve and its seat, reducing the valve lift and therefore its lift. This causes poor valve opening and therefore a deterioration in the discharge coefficient.

[0008] Thus, the known free valves used in cryogenic pumps have the disadvantage of having a low discharge coefficient due to the slight depression which occurs in the conical zone which degrades the lift of the valve.

[0009] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

[0010] To this end, the valve according to the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that the frustoconical surface of the head comprises at least one irregularity forming a rib and / or a groove configured to generate turbulence within the fluid flowing between the head and the seat.

[0011] The modification of the structure of the valve makes it possible to reduce this depression. This allows a reestablishment of the pressure in the conical portion which makes it possible to break the depression and allows the valve to better lift under the effect of the pressure and consequently increases its discharge coefficient.

[0012] Furthermore, embodiments of the invention may include one or more of the following features: - the least irregularity is machined on the head, - the at least irregularity is formed by a continuous or discontinuous variation of the thickness of the truncated portion, - the at least one irregularity comprises a circumferential groove located on the frustoconical portion and forming a localized recess on the frustoconical portion of the head, - the truncated surface of the head comprises several irregularities, for example two or three or four, arranged in series along the truncated portion, - the plurality of irregularities arranged in series along the truncated portion forms a “stepped” profile along the truncated portion, - the valve is of the “free” type, i.e. not controlled by an actuator and whose opening and closing are achieved by the pressure differential between its ends.

[0013] The invention also relates to a pump for multiphase liquid or fluid, for example cryogenic, comprising at least one compression chamber, a piston movable relative to the compression chamber, a system for admitting fluid into the compression chamber, the admission system comprising a valve according to any one of the characteristics above or below.

[0014] The invention may also relate to any alternative device or method comprising any combination of the above or below features in the framework of claims.

[0015] Other features and advantages will appear on reading the description below, given with reference to the figures in which: Brief description of the figures

[0016] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0017] [Fig-1] is a schematic view in longitudinal section of a valve according to the art prior,

[0018] [Fig.2] is a schematic side view of a valve flap according to a first exemplary embodiment of the invention,

[0019] [Fig.3] is a schematic side view of a valve flap according to a second exemplary embodiment of the invention,

[0020] [Fig.4] is a schematic side view of a valve flap according to a third exemplary embodiment of the invention,

[0021] [Fig.5] is a schematic side view of a valve flap according to a fourth exemplary embodiment of the invention,

[0022] [Fig.6] is a schematic side view of a valve flap according to a fifth embodiment of the invention,

[0023] [Fig.7] is a schematic side view of a valve flap according to a sixth embodiment of the invention.

[0024] [Fig.8] is a schematic view comparing the flow rate F as a function of the pressure differential DP (in mbar) for a valve according to the prior art (curves with crosses) and for an exemplary embodiment of the invention (curve with points).

[0025] [Fig.9] is a schematic sectional view of an example of a cryogenic pump capable of using such a valve. Detailed description

[0026] In all the figures, the same references refer to the same elements.

[0027] In this detailed description, the following embodiments are examples. Well that the description refers to one or more embodiments, this does not mean that the features apply only to a single embodiment. Single features of different embodiments may also be combined and / or interchanged to provide other embodiments.

[0028] The conical liquid inlet valve 1 comprises a flap 2. The flap 2 has a body which extends in a longitudinal direction and is provided at one longitudinal end with a truncated cone-shaped head 12 diverging towards the terminal end.

[0029] The valve 1 further comprises a truncated cone-shaped seat 3 conjugated with the head 12. The flap 2 and the seat 3 are relatively movable between a closed configuration in in which the head 2 cooperates in a sealed manner with the seat 3 to prevent the passage of fluid and an open configuration in which the head 2 is spaced from the seat 3 to allow a passage of fluid. For example, the valve 2 is movable in translation relative to the fixed seat 3 in a longitudinal direction.

[0030] According to an advantageous feature, the frustoconical surface of the head 12 comprises at least one irregularity 22 forming a rib and / or a groove configured to generate turbulence within the fluid flowing between the head 2 and the seat 3.

[0031] That is to say that the truncated conical zone of the valve 2 has one or more reliefs 22 allowing the flow of fluid in the conical zone to acquire a little turbulence in order to decelerate it and increase the pressure in this zone.

[0032] The relief(s) 22 may be machined on the head 2 and / or be obtained by molding.

[0033] As illustrated in [Fig.6] and [Fig.7], the frustoconical surface may comprise a single circular groove extending around the longitudinal direction. This forms relief variations for fluid flow in this area.

[0034] As illustrated, this variation in dimension of the truncated cone zone can be progressive (without protruding or sharp angles).

[0035] As illustrated in [Fig.2], [Fig.3], [Fig.4] and [Fig.5], the frustoconical surface of the head of the valve 2 may comprise reliefs or patterns 22 which are repeated along the conical zone (in the longitudinal direction). For example, the frustoconical surface of the head 12 comprises several irregularities 22, for example two, three, four or five (or more) arranged in series along the frustoconical portion.

[0036] As illustrated, these reliefs arranged in series along the frustoconical portion can form a “stepped” profile along the frustoconical portion (shoulders or projecting angles for example).

[0037] [Fig.8] illustrates the results of experimental tests comparing the flow rates F through two valves as a function of the pressure differential DP applied on either side of the valve. The two valves compared have the same mass and are made of resin.

[0038] A first valve 2 (curve with cross) has a truncated head according to the prior art (without relief) the other valve 2 (curve with points) has three reliefs in series (according to [Fig.2]). The other geometric parameters are identical. The curves illustrate a better discharge coefficient for the valve according to the invention. This advantage is also valid for the other embodiments.

[0039] The invention can be applied advantageously for example:

[0040] to cryogenic pumps with inlet valve,

[0041] to liquid pumps with inlet valve,

[0042] to multiphase pumps with inlet valve.

[0043] The invention can be applied in particular to liquid hydrogen pumps, pumps of liquid helium.

[0044] The invention can be applied to piston or membrane compressors / pumps, to valves with high frequency of use (unlike a safety valve), for admission and / or discharge.

[0045] The invention makes it possible in particular to satisfy the need for very high sealing to guarantee the performance of the machine.

[0046] For example, the valve 1 may be provided to ensure the admission of fluid into a compression chamber of a single-stage compression cryogenic pump 10 or, as shown in [Fig. 9] for one or both of the compression chambers 3, 4 of a two-stage compression pump (two compression chambers 3, 4).

[0047] The invention applies advantageously to free valves but the advantages can be applied to other types of valves.

Claims

Claims

1. Conical liquid inlet valve, in particular for a cryogenic fluid pump, comprising a valve (2) having a body provided with a frustoconical head (12) and a frustoconical seat (3) mated with the head (12), the valve (2) and the seat (3) being relatively movable between a closed configuration in which the head (2) cooperates in a sealed manner with the seat (3) to prevent the passage of fluid and an open configuration in which the head (2) is spaced from the seat (3) to allow a passage of fluid, characterized in that the frustoconical surface of the head (12) comprises at least one irregularity (22) forming a rib and / or a groove configured to generate turbulence within the fluid flowing between the head (2) and the seat (3).

2. Valve according to claim 1, characterized in that the at least one irregularity (22) is machined on the head (2).

3. Valve according to claim 1 or 2, characterized in that the at least one irregularity (22) is formed by a continuous or discontinuous variation in the thickness of the frustoconical portion.

4. Valve according to any one of claims 1 to 3, characterized in that the at least one irregularity (22) comprises a circumferential groove located on the frustoconical portion and forming a localized recess on the frustoconical portion of the head (2).

5. Valve according to any one of claims 1 to 4, characterized in that the frustoconical surface of the head (12) comprises several irregularities (22), for example two or three or four, arranged in series along the frustoconical portion.

6. A valve according to claim 5, characterized in that the plurality of irregularities (22) arranged in series along the frustoconical portion forms a "stepped" profile along the frustoconical portion.

7. Valve according to any one of claims 1 to 6, characterized in that it is of the “free” type, that is to say not controlled by an actuator and the opening and closing of which are achieved by the pressure differentials between its ends.

8. Pump for liquid or multiphase fluid, for example cryogenic, comprising at least one compression chamber (3, 4), a piston (5, 8) movable relative to the compression chamber, a system for admitting fluid into the compression chamber (3, 4), characterized in that the admission system comprises a valve according to one of any of the preceding claims.