Conical valve and pump incorporating such a valve

Abstract

The invention relates to a conical liquid inlet valve, particularly for a cryogenic fluid pump, comprising a valve (2) having a body with a frustoconical head (12) and a frustoconical seat (3), the valve (2) and the seat (3) being movable relative to each other between a closed configuration in which the head (2) seals tightly with the seat (3) to prevent fluid passage and an open configuration in which the head (2) is spaced away from the seat (3) to allow fluid passage, characterized in that the angle of the frustoconical surface defined by the seat (3) is more flared than the angle of the frustoconical surface of the head (12) and in that the frustoconical end of the head (12) with the smaller diameter has a rounded or chamfered surface (22) ensuring a seal with the seat (3) in the closed configuration. (Short figure: Fig. 1)

Description

Title of the invention: Conical valve and pump comprising such a valve

[0001] The invention relates to a conical valve and to a pump comprising such a valve.

[0002] The invention relates more particularly to a conical liquid admission valve, in particular for a cryogenic fluid pump, comprising a valve having a body provided with a frustoconical head and a frustoconical seat, 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.

[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] In order to increase the performance and volumetric efficiency, particularly of pumps for liquid hydrogen, it is essential that the pressurization chamber or chambers (in the case of a pump with several pressurization stages) remain very tight during the pressurization phase. This is particularly crucial when pressures above 900 bar are reached. Each pumping stage has a flap valve which allows the chamber to be filled during the intake phase and closes during pressurization and ensures that the fluid does not return. Seals are also provided to ensure the seal between the compression piston and the sleeve during movement and in particular during pressurization.

[0007] The sealing of the valves of the inlet valves is essential for the operation of the pumps, in particular, if the pump is intended to pump fluid cryogenic. Poor sealing significantly degrades the volumetric efficiency because part of the flow rate is lost (and by Joules-Thomson effect, if it is hydrogen, reheating can be generated, causing more difficulties in filling). In addition, poor sealing at the inlet valve also creates a loss in volumetric efficiency and losses by vaporization, due to the same Joules-Thomson effect, mentioned above. In the latter case, it is the pressurized fluid that expands through the valve in the wrong direction during the pressurization phase. This brings heat to the upstream part of the chamber. In some cases, especially when the fluid in the upstream part is close to saturation, this causes an additional and considerable loss of liquid by vaporization ("boil-off gas" in English or "BOG").

[0008] Known truncated cone-shaped valves have the risk of not being very watertight due to a potential poor landing on the valve seat.

[0009] Another known solution consists of using a valve having a spherical shape which improves the seal but has the disadvantage of generating a significant dead volume. Not only can this dead volume be a source of degradation of volumetric efficiency but also a source of heating due to the expansion thus causing the temperature of the chamber to rise and difficulty in filling it during admission.

[0010] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

[0011] 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 angle of the frustoconical surface defined by the seat is more flared than the angle of the frustoconical surface of the head and in that the frustoconical end of the head of smaller diameter has a rounded or filleted surface ensuring sealing with the seat in the closed configuration.

[0012] Furthermore, embodiments of the invention may include one or more of the following features: - in closed configuration, the truncated end of the larger diameter head is spaced from the seat, - the difference between the angle of the frustoconical surface defined by the seat and the angle of the frustoconical surface of the head is between 0.5 and 8 degrees, preferably between 1 and 5 degrees, - the rounded or filleted surface ensuring the seal with the seat in the closed configuration forms a rounding whose radius R is a function of the diameter D of the widest end of the truncated head, for example such as 0.2 <R / D<0,25, - 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, in which the admission system comprises 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 within the scope of the 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 anterior in open position,

[0018] [Fig.2] is a schematic view in longitudinal section of a valve according to the prior art in the closed position,

[0019] [Fig.3] is a schematic side view of a detail of the valve illustrating the flap in the closed position on its seat according to an exemplary embodiment of the invention. Detailed description

[0020] In all the figures, the same references refer to the same elements.

[0021] 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.

[0022] 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. The most flared end of head 12 has a diameter D.

[0023] The valve 1 further comprises a truncated cone-shaped seat 3. The flap 2 and the seat 3 are 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 passage of fluid. For example, the valve 2 is movable in translation relative to the seat 3 fixed in the longitudinal direction.

[0024] According to an advantageous feature, the angle of the frustoconical surface defined by the seat 3 is more flared than the angle of the frustoconical surface of the head 12 and the frustoconical end of the head 12 of smaller diameter has a rounded or filleted surface 22 ensuring sealing with the seat 3 in the closed configuration.

[0025] For example, the angle of the frustoconical surface of the seat relative to the longitudinal direction is between 20 and 45 degrees.

[0026] Thus, in the closed position, the head 12 of the valve rests on the seat 3 at its lower base (the least flared end of the truncated cone). The head 12 thus has a fillet or a slight rounding, preferably spherical, which ensures that this landing on the seat 3 is not disturbed by the cone formed by the valve.

[0027] For example, the angle A of the truncated cone formed by the head 12 of the valve is slightly different from the angle B formed by the truncated cone formed by the seat, for example this difference AB=C is between 0.5 and 8 degrees, preferably between 1 and 5 degrees.

[0028] Similarly, the radius R of the lower rounding 22 can be defined as follows: the ratio of the radius R to the largest diameter D of the truncated cone of the head 12 is between 2 and 25%. That is to say that: 0.02 <R / D<0,25.

[0029] In this way, in the closed configuration, the seal between the valve and the seat 3 is achieved on a spherical profile while reducing the dead volume due to the conservation of the conical profile beyond the rounding and up to the more flared upper base of the valve 2.

[0030] The invention can be applied advantageously for example: - to cryogenic pumps with inlet valve, - to liquid pumps with inlet valve, - to multiphase pumps with inlet valve.

[0031] The invention can be applied in particular to liquid hydrogen pumps, liquid helium pumps.

[0032] For example, the valve 1 may be provided to ensure the admission and / or discharge of fluid into a compression chamber 3 of a single-stage compression cryogenic pump or for one or both compression chambers of a two-stage compression pump (not shown) (two compression chambers).

[0033] The valve can be used as a discharge and / or pressure relief valve in a pump, for example for liquid hydrogen. This valve can also be used in piston volumetric compressors.

[0034] 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.

[0035] The invention makes it possible in particular to satisfy the need for very high sealing to guarantee the performance of the machine.

[0036] 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), 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 angle (B) of the frustoconical surface defined by the seat (3) is more flared than the angle (A) of the frustoconical surface of the head (12) and in that the frustoconical end of the head (12) of smaller diameter has a rounded or filleted surface (22) ensuring sealing with the seat (3) in the closed configuration.

2. Valve according to claim 1, characterized in that, in the closed configuration, the frustoconical end of the head (12) of larger diameter (D) is spaced from the seat (3).

3. Valve according to claim 1 or 2, characterized in that the difference (C) between the angle (B) of the frustoconical surface defined by the seat (3) and the angle (A) of the frustoconical surface of the head (12) is between 0.5 and 8 degrees, preferably between 1 and 5 degrees.

4. Valve according to any one of claims 1 to 3, characterized in that the rounded or filleted surface (22) ensuring sealing with the seat (3) in the closed configuration forms a rounding whose radius (R) is a function of the diameter (D) of the widest end of the truncated head (12), for example such that 0.2 <R / D<0,25.

5. Valve according to any one of claims 1 to 4, 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.

6. Pump for liquid or multiphase fluid, for example cryogenic, comprising at least one compression chamber (3), a piston (4) movable relative to the compression chamber, a system for admitting fluid into the compression chamber (3), characterized in that the admission system comprises a valve (1) according to any one of the preceding claims.

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