Patent Description:
The invention further relates to a kit of parts, an irrigation system and a method of regulating a flow of fluid.

Water is a scarce resource in many regions of the world and thus needs to be efficiently used and its supply carefully regulated and controlled. For instance, in the Western world a great deal of clean drinking water is wasted by individuals in taking a bath or shower. Despite the fact that many measures have been taken in Western countries, the amount of energy involved in a shower or bath has continued to increase relatively.

Pressure-independent flow regulators or limiters are marketed very successfully by applicant, particularly in the United Kingdom and other countries. Such flow limiters are for instance described in <CIT> and the <CIT>.

<CIT> discloses a fluid flow regulator comprising a valve chamber having a fluid inlet and a fluid outlet. There is a valve member inside the valve chamber. The valve member is moveable inside the valve chamber and contactable with a valve seat of the flow regulator inside the valve chamber. The fluid flow regulator includes a check valve.

Compared to flow limiters of other manufacturers, which usually make use of rubber rings and the like, a considerable improvement is obtained with these known flow limiters, this being due to the ability of these known flow limiters of applicant to provide over a period of years an accurate flow rate of for instance <NUM> (+/- <NUM>) litres per minute within a (dynamic) pressure interval of <NUM>-<NUM> bar. Existing flow limiters of other manufacturers appear in practice to generate a much less constant and accurate flow rate, particularly in the case of pressure loss (pressure drop), this being particularly undesirable in the case of showers and the like and with the aim of comfortable use of water.

There is also a need in agricultural sector for flow limiters, for instance in irrigation installations. Savings in the costs of installations are hereby considerable. Generally, there is a need for a flow regulating device which operates in a broad field of use.

This goal, amongst other goals, is met by a flow regulating device according to claim <NUM>. More specifically, this goal is met by a flow regulating device for regulating a fluid flow therethrough, comprising a fluid inlet for fluid to flow into the flow regulating device, a fluid outlet for the fluid to flow out of the flow regulating device, and a fluid channel extending from the fluid inlet to the fluid outlet, wherein the flow regulating device further comprises:.

By arranging the pressure enhancing device to increase the inlet pressure, a flow regulating element for providing an accurate flow rate at an operating pressure in a particular range can be operated in lower pressure applications and, as such, in a broad field of use.

It was found that although flow regulating elements, for instance those as referred to in the introduction, operate well under normal conditions, i.e., output a substantially constant flow rate under varying pressures, the operation can be improved in lower pressure ranges. As such, by providing a pressure enhancing device, a lower inlet pressure can be enhanced, i.e., increased to an inlet pressure within the optimal working pressure range of the flow regulating element.

According to a preferred embodiment, the pressure enhancing device comprises a tubular member having an inlet end and an outlet end having a cross-sectional area exceeding the cross-sectional area of the inlet end, wherein the flow regulating element is fluidly connected with the outlet end of the tubular member. An efficient, robust and reliable pressure enhancer is thus provided. Moreover, the tubular member can passively enhance the inlet pressure of the flow regulating element.

Preferably, the cross-sectional area of the tubular member smoothly increases along the tubular member as seen from the fluid inlet to the regulator inlet. A non-turbulent flow is thus obtained, which increases the reliability of the downstream flow regulating element.

According to a preferred embodiment, the pressure enhancing device is arranged to increase the pressure of the fluid in the regulator inlet by at least <NUM> percent, preferably at least <NUM> percent, relative to the pressure of the fluid flowing through the fluid inlet.

Preferably, the pressure enhancing device is arranged for increasing a fluid pressure of <NUM>-<NUM> bar in the fluid inlet to at least <NUM> bar in the regulator inlet, more preferably of <NUM> bar in the fluid inlet to <NUM> bar in the regulator inlet.

The flow regulating device further comprises a housing for housing the flow regulating element and the flow regulator. The housing may comprise an inlet and an outlet, arranged to fluidly couple to the inlet of the pressure enhancing device and the outlet of the flow regulating element. Preferably, the housing is tubular, making it efficient to couple the housing in a liquid ducts, such as water piping or hoses. The housing, or the flow regulating device in general, is preferably provided with suitable coupling means, for instance threading or operating by a snap-fit connection, to couple to a liquid duct system.

The housing comprises an inlet segment, and preferably a regulator segment and an outlet segment. The pressure enhancing device is arranged in the inlet segment. Preferably, the flow regulating element is arranged in the regulator segment, and the outlet segment defines the fluid outlet.

Preferably, the inner diameter of the tubular housing varies stepwise across the segments. This allows efficient fitting of the components. The flow regulating element is preferably snugly, i.e., without substantial play, arranged in the flow regulator segment of the tubular housing and preferably has an outer diameter exceeding the inner diameter of the outlet segment of the tubular housing. Preferably, the pressure enhancing device is snugly arranged in the inlet segment of the tubular housing and preferably has an outer diameter exceeding the inner diameter of the regulator segment. The steps between the segments, i.e., the change of diameter of the segments as mentioned above, may serve to accurately place the components in the housing by receiving an end face of these components. Preferably, the tubular housing and/or the pressure enhancing device is manufactured via an additive manufacturing technique.

The housing, the pressure enhancer and the flow limiting element are preferably separate parts which are received in the housing. In the alternative, at least some of the components may be formed integrally. The pressure enhancer, for instance in the form of the tubular member as explained above, may be formed integrally with the housing. A flow regulating element can also be fitted into the housing. As a further alternative, also the flow limiting element may be formed integrally or the flow limiting element may be integrally provided with a pressure enhancer as described.

According to a preferred embodiment, the flow regulating element defines a throughflow opening and is arranged to adjust the size of the throughflow opening in dependence of a pressure of the fluid flowing through the flow regulating element to regulate the flow rate of the fluid flowing through the fluid outlet. Typically, such a flow regulating element has an optimal working range in terms of inlet pressures, wherein the pressure enhancer is preferably arranged to enhance an inlet pressure to within said optimal working range.

Preferably, the flow regulating element comprises a valve seat and a resilient plate-like valve element defining the throughflow opening therebetween, wherein the valve element is arranged movable to and from the valve seat under the influence of the pressure of the fluid flowing through the flow regulating element to adjust the size of the throughflow opening.

The flow limiting element, or simply flow limiter, works by restricting the throughflow opening between the resilient plate-like valve element and the valve seat when the pressure increases. Such an increased pressure will act on the upstream side of the resilient plate-like valve element whereby it will bend, such that the resilient plate-like valve element moves towards the valve seat, whereby the throughflow opening is reduced and the flow is limited, or at least kept substantially constant with increasing pressure. Such a flow limiting element is described in <CIT> and the <CIT>.

According to a preferred embodiment, the flow regulating element is arranged to regulate the fluid flowing through the fluid outlet to flow at a predefined flow rate, preferably substantially independent of the inlet pressure. Preferably, the predefined flow rate is in the range of <NUM> to <NUM>, more preferably <NUM> to <NUM>, litres per minute.

According to a further aspect, a pressure enhancing device, in particular for use in a flow regulating device according to any of the above embodiments, is provided. A preferred embodiment comprises a tubular member having an inlet end for defining a fluid inlet, and an outlet end having a cross-sectional area exceeding the cross-sectional area of the inlet end to increase the pressure of a fluid flowing through the outlet end relative to the pressure of the fluid flowing through the fluid inlet.

Preferably, the cross-sectional area of the tubular member smoothly increases along the tubular member as seen from the inlet end to the outlet end.

Preferably, the cross-sectional area of the outlet end is at least <NUM>, more preferably at least <NUM>, times the cross-sectional area of the inlet end.

Preferably, the tubular member is manufactured via an additive manufacturing technique. The pressure enhancer may be provided with a housing, more preferably integrally, as described above. In the alternative, the pressure enhancer is arranged to cooperate with the housing as separate constructional elements.

According to a further aspect, a kit of parts according to claim <NUM> is provided.

According to a further aspect, a liquid duct system, for instance a water piping system or water duct system, is provided with at least one flow regulating device as described above. Such a system is then capable of providing a substantially constant flow rate, irrespective of the inlet pressures. In particular in irrigation systems, great water savings can be achieved. As such, according to a further aspect, an irrigation system is provided comprising at least one flow regulating device as described above.

According to a further aspect, this goal is met by a method of regulating a flow of fluid, comprising the steps of providing a flow regulating device, preferably as discussed above, and arranging the flow regulating device for the fluid to flow into the fluid inlet of the flow regulating device and out of the fluid outlet of the flow regulating device.

The present invention is further illustrated by the following Figures, which show preferred embodiments of the flow limiting device and components, and are not intended to limit the scope of the invention in any way, wherein:.

<FIG> show a flow regulating assembly <NUM> for regulating a fluid flow therethrough, comprising a tubular housing <NUM> (illustrated by dashed lines), provided with an inlet <NUM> and an outlet <NUM>, and a flow regulating element <NUM> arranged in the housing <NUM> to regulate a flow rate of fluid flowing therethrough.

The flow regulating element is illustrated in more detail in <FIG>, which shows a cross-sectional view of the flow limiting element <NUM> according to a first embodiment. The flow regulator <NUM> comprises a regulator housing <NUM> which has, as a regulator inlet <NUM>, a fluid opening on the upstream side and, as a regulator outlet <NUM>, a fluid opening on the downstream side. The direction of flow is indicated by the different arrows A and is in the direction as seen from the inlet <NUM> to the outlet <NUM>. Within the housing <NUM>, a resilient plate-like valve element <NUM> is arranged, comprising a retained section <NUM> and a resiliently movable section <NUM>. The plate-like resilient valve element <NUM> is supported on a support part <NUM> in the central downstream part of housing <NUM>, wherein said support part <NUM> and a cushion part <NUM> in the peripheral upstream part of housing <NUM> hold in place the retained section <NUM> of resilient plate-like valve element <NUM>. This fixation is brought about as follows. The resilient valve element <NUM> in principle lies unattached in housing <NUM> and is supported on one side over the whole width by support part <NUM> and held in place by a pin <NUM> on support part <NUM> which fits loosely in a hole arranged in resilient element <NUM>. Both sides, i.e. the smaller retained section <NUM> and the larger resilient section <NUM> of the resilient element are exposed to the water pressure and a force is therefore exerted on both sides. The outer end of retained section <NUM> on the opposite side of resilient valve element <NUM> rests against cushion <NUM>, whereby the resilient valve element <NUM> is fixed in its position by the flow of the liquid. The size of the throughflow opening <NUM> can be adjusted in the rest state of valve element <NUM> by adjusting the thickness of cushion <NUM>. The resilient section <NUM> of plate-like valve element <NUM> determines, together with a valve seat <NUM> with thickness <NUM> inclining downward to the outer end of resilient part <NUM>, the width and length of the throughflow opening <NUM>, wherein said opening <NUM>, together with the space <NUM> lying on the liquid outlet side of resilient element <NUM>, realizes a pressure drop such that the liquid flow rate at the outlet <NUM> is constant.

As shown in <FIG>, the assembly <NUM> further comprises a pressure enhancing device in the form of a tubular member <NUM>. With reference to <FIG>, the tubular member <NUM> has an inlet end <NUM> with a constant inner diameter D<NUM> along its length L<NUM> and an outlet end <NUM> with a constant outer diameter D<NUM> and a constant inner diameter D<NUM> along its length L<NUM>. The inner diameter D<NUM> of the outlet end <NUM> exceeds the inner diameter D<NUM> of the inlet end <NUM>. From the inlet end <NUM> to the outlet end <NUM>, the inner diameter of the tubular member <NUM> smoothly increases along a midsection <NUM> of the tubular member <NUM>. Along a central cross-sectional region <NUM> of the midsection <NUM> with a length denoted as L<NUM>, the diameter increase rate is substantially constant, while neighbouring curved regions <NUM>, <NUM> of the midsection <NUM> at either side of the central region <NUM>, smoothly connect the central region <NUM> to the inlet end <NUM> and the outlet end <NUM>, respectively. As such, the tubular member <NUM> is arranged to increase the pressure of a fluid flowing therethrough by more than <NUM> percent, specifically from <NUM> bar in the inlet end <NUM> to <NUM> bar in the outlet end <NUM>.

According to a specific embodiment of the pressure enhancer <NUM>, the inner diameter D<NUM> of the inlet end <NUM> is between <NUM> and <NUM>, specifically <NUM>, while the inner diameter D<NUM> of the outlet end <NUM> is between <NUM> and <NUM>, specifically <NUM>. More generally, the inner diameter D<NUM> of the outlet end <NUM> is preferably about twice the inner diameter D<NUM> of the inlet end <NUM>. The length L<NUM> of the inlet end <NUM> may be between <NUM> and <NUM>, specifically <NUM>, while the length L<NUM> of the outlet end <NUM> may be between <NUM> and <NUM>, specifically <NUM>. The central region <NUM> has a length L<NUM> of between <NUM> and <NUM>, specifically <NUM>, and extends at an angle with the inlet end <NUM> of between <NUM> and <NUM> degrees, preferably between <NUM> and <NUM> degrees, specifically <NUM> degrees. The curved regions <NUM>, <NUM> of the midsection <NUM>, connecting the central region <NUM> with the inlet end <NUM> and the outlet end <NUM>, each have a radius of curvature of between <NUM> and <NUM>, specifically <NUM> and <NUM> respectively. Along its length, the tubular member <NUM> has a wall thickness of about <NUM>.

The diameter of the tubular housing <NUM> varies stepwise over its length, thereby defining in order of decreasing diameter, with reference to <FIG>, an inlet segment <NUM> with a first inner diameter D<NUM>, a midsegment <NUM> with a length L<NUM> and a second inner diameter D<NUM>, and an outlet segment <NUM> with a third inner diameter D<NUM>. Referring again to <FIG>, the pressure enhancer <NUM> having an outer diameter D<NUM> corresponding to the first inner diameter D<NUM> is snugly held in the inlet segment <NUM>, with its outlet end <NUM> abutting a shoulder <NUM> of the midsegment <NUM>. Similarly, the flow regulating element <NUM>, having an outer diameter and a length corresponding to the second inner diameter D<NUM> and the length L<NUM> of the midsegment <NUM>, is snugly held in the midsegment <NUM>, with its outlet <NUM> abutting a shoulder <NUM> of the outlet segment <NUM>. When the inner diameter D<NUM> of the outlet end <NUM> of the tubular pressure enhancer <NUM> is slightly smaller than the outer diameter of the flow regulating element <NUM>, the flow regulating element <NUM> can be secured between the outlet end <NUM> of the pressure enhancer <NUM> and the shoulder <NUM> of the outlet segment <NUM> of the housing <NUM> for an efficient assembly of the assembly <NUM>. In general, the assembly <NUM> can be conveniently assembled by first inserting the flow regulating element <NUM> into the housing <NUM> via the inlet <NUM> and installing the inserted regulator <NUM> in the midsegment <NUM> of the housing <NUM> and, lastly, installing the pressure enhancer <NUM> in the inlet segment <NUM> via the inlet <NUM>. The housing <NUM> therewith functions as a holding jacket.

According to a specific embodiment of the tubular housing <NUM>, the inner diameter D<NUM> of the inlet segment <NUM> is between <NUM> and <NUM>, specifically <NUM>. The inner diameter D<NUM> of the midsegment <NUM> is between <NUM> and <NUM>, specifically <NUM>. The inner diameter D<NUM> of the outlet segment <NUM> is between <NUM> and <NUM>, specifically <NUM>. The length L<NUM> of the midsegment <NUM> is between <NUM> and <NUM>, specifically <NUM>.

The flow regulating assembly <NUM> can be installed in a water installation, particularly a tubing system thereof (not shown), to keep the flow rate of water flowing therethrough constant, e.g. at a rate of <NUM> lpm. Hereto, the inlet end <NUM> of the pressure enhancer <NUM> and the outlet <NUM> are fluidly connected to respective tubes of the system. The flow regulating element <NUM> has shown to optimally operate at higher pressures, in particular pressures of above <NUM> bar. For applications of the flow regulating element <NUM> in a lower operating pressure range, it was found that the flow rate ultimately falls below the desired flow rate. By retrofitting the pressure enhancer <NUM>, a relatively low inlet pressure of, e.g., <NUM>-<NUM> bar can be increased to, e.g., <NUM> bar, such that the flow regulating element <NUM> can operate within its optimal pressure range.

The modular configuration of the assembly <NUM> allows the retrofitted pressure enhancer <NUM> to be replaced, depending on the specific flow limiting element <NUM> and its application, flow rate and optimal operating pressure range.

A series of experiments have been performed, wherein the inlet pressure has been varied using a low-pressure range pump from the initial condition of <NUM> bar to <NUM> bar at several increments and the resulting flow rate has been measured at each pressure.

The tests have been repeated for each situation as detailed in Table <NUM> and Table <NUM>. Accordingly, a total of <NUM> experiments have been performed.

The experiments show that the flow regulating device is effective even at relatively low inlet pressures.

Claim 1:
Flow regulating device (<NUM>) for regulating a fluid flow therethrough, comprising a fluid inlet (<NUM>) for fluid to flow into the flow regulating device, a fluid outlet (<NUM>) for the fluid to flow out of the flow regulating device, and a fluid channel extending from the fluid inlet (<NUM>) to the fluid outlet (<NUM>), wherein the flow regulating device (<NUM>) further comprises:
- a flow regulating element (<NUM>) provided with a regulator inlet (<NUM>) and arranged in the fluid channel to regulate a flow rate of the fluid flowing through the fluid outlet (<NUM>);
- a housing (<NUM>) for housing the flow regulating element (<NUM>), wherein the housing comprises an inlet segment (<NUM>),
characterised by a pressure enhancing device (<NUM>) arranged in the inlet segment (<NUM>) to increase the pressure of the fluid in the regulator inlet (<NUM>) relative to the pressure of the fluid flowing through the fluid inlet (<NUM>).