FR2892795A1 - Product limiter for a device flowing directly into the atmosphere is formed by two elements, with one of them fixed and the other movable under the effect of a pressure - Google Patents

Abstract

The product limiter for a device flowing directly into the atmosphere is formed by two elements (4, 5), with one of them fixed and the other movable under the effect of a pressure. The annular space (6) formed by them has a a section which diminishes in the direction of the liquid flow.

Description

The present invention relates to an automatic flow limiter for

  hydraulic device flowing directly to the atmosphere and, more particularly, for flush valves.

  In a flush valve, it is preferable that the flow rate be substantially constant as a function of the supply pressure in order to maintain correct operating characteristics and to control the quantity of water delivered. As the pressure of the distribution network is not constant it is necessary to interpose in the flow of water a flow control member.

  It is well known that when working on a circulating fluid to reduce its flow rate, the acoustic level of the installation is degraded. Experience has shown that the devices currently used to regulate the flow rate do not make it possible to obtain a satisfactory acoustic level.

  The flow limiter of the invention is constituted by the cooperation of two parts, a sleeve and a central core, forming between them an annular space, the section of which decreases in the direction of flow of the fluid, one of said parts being axially movable, the force exerted by the pressure on the movable part being balanced by an opposing spring.

  As the pressure increases, the moving part moves, which has the effect of reducing the section of the annular exit space and, consequently, the flow rate of the apparatus.

  The present invention will be better understood from the following description given with reference to the accompanying drawings by way of example only, in which: - Figure 1 is a sectional view of a valve comprising the device 5 of the invention; - Figure 2 is a view similar to that 1, showing the position of the moving part when the pressure increases; - Figure 3 shows an alternative embodiment; FIG 4 is a view similar to Figure 1 showing another embodiment 10.

  Referring to the drawings, we see that the valve is shown schematically by a body in two parts 1 and 2, assembled by trapping the seat 3, usual. According to the invention, the limiter is interposed between the seat 3 and the outlet S which is at atmospheric pressure.

  The limiter is formed by the combination of two parts, namely: a sleeve 4 and a central core 5, forming between them an annular space 6 whose section decreases from the upper part to the output S.

  According to one embodiment, the central core is stationary and the sleeve 4 can move, under the action of pressure, against an antagonistic spring 7.

  The core 5 is connected by fins 8 to an axially immobilized ring 9. To the outlet S, the bore of the bushing 4 has a portion 10, the section of which increases in the direction of flow of the fluid. Above the portion 10, the bore of the bushing may be cylindrical, the decrease of the section of the annular space 6 being obtained by providing a core whose section decreases from its upper part to the lower one.

  If we refer to Figure 1, we see that the output section S1 has a maximum value. If the pressure increases, the bushing 4 moves downwards and the output section takes a value S2 which is smaller than Si.

  Figure 3 shows an alternative embodiment in which the sleeve has a first portion 10a, variable section, and a second portion 1 Ob, the two portions being separated by a cylindrical portion January 1 (a third portion is naturally possible). This embodiment makes it possible to use the same limiter on sites whose minimum and maximum values of the pressure are different (for example, the portion 10a corresponds to a variation of 1 to 1.5 bars, that 1 Ob corresponding to a variation of 2 to 2, 5 bars).

  Figure 4 shows another embodiment in which the central core 1 2 is movable, the sleeve can then be an integral part of the body part 2a.

  The core 1 2 is connected by fins 1 3 to a ring 14 which, under the action of pressure, descends by compressing a spring 1 5.

  At its lower end, the core 1 2 has a portion 16 whose diameter decreases in the fluid flow direction.

  As the pressure increases, the output section S3 decreases. The annular section 6 is thus always decreasing when the core 1 2 goes down.

  In the same spirit as the embodiment of Figure 3, the core 1 2 may comprise several portions 1 6.

  It should be noted that the good acoustic result obtained by the limiter of the invention is explained by the fact that the passage section of the fluid is always decreasing in the direction of flow so that its speed is always increasing, that output being maximum. This avoids the creation of cavitating zones, sources of high noise resulting from the implosion of water vapor bubbles occurring when the value of the pressure drops below atmospheric pressure following a passage at high speed.

Claims (6)

  1-Flow limiter for hydraulic device flowing directly to the atmosphere, characterized in that it is constituted by the association of two parts (4, 5), one of which is fixed and the other is movable under the action of the pressure, providing between them an annular space (6) whose section decreases in the direction of flow of the fluid.   2-Limiter according to claim 1, characterized in that it comprises a central core 5, fixed, housed inside a sleeve (4) movable axially under the action of the pressure against a counter-spring (7).   3- limiter according to claim 2, characterized in that the bore of the sleeve (4) has, in the vicinity of the lower end of the core (5), at least a portion (10) whose section increases in the flow direction of the fluid such that the section of the annular space (6) decreases as the bushing moves against the counter spring.   4-limiter according to claim 1, characterized in that the sleeve (2a) 20 is fixed while the central core is axially movable under the action of the pressure against a counter spring (1   5). 5-limiter according to claim 4, characterized in that the core (1 2) has at its lower end, at least, a portion (1   6) whose diameter decreases in the direction of flow of the fluid so that the section of the annular space (6) decreases as the core (1 2) moves against the counter spring. 5