Patent Description:
In a shower system, a means operable to produce a principal stream of water having a user-desired temperature may be employed. The means operable to produce the principal stream of water having the user-desired temperature may include, for example, a mixer valve, e.g. a thermostatic mixer valve, or an instantaneous water heater. The principal stream of water having the user-desired temperature is then conveyed to a fluid delivery device such as a shower head. Typically, the shower system may comprise one or more user input means operable to control the temperature and/or the flow of water delivered by the fluid delivery device.

<CIT> discloses a valve for a flush-mounted body of a sanitary fitting comprising a valve housing having a cold water connection, a hot water connection and a drain connection for forwarding a tempered liquid. It also discloses a volume flow control unit and a temperature control unit.

<CIT> discloses a shower controlling device comprising a switching valve spaced apart from a mixing valve, said switchining valve being suitable for controlling the switching on/off of an outlet tube.

<CIT> discloses a self-closing water-saving device that employs the use of an elastic force of an elastic member and oil flowing or friction to close the device in a constant time after it is opened.

<CIT> discloses a multifunctional shower which has a built-in water purifier and the device may be switched between raw water output and purified water output and there is a flow regulating mechanism comprising a gear drive shaft.

<CIT> discloses a metering valve comprising holes at one end such that the metering valve allows a uniform rate of discharge of fluid per unit movement of a cam without resorting to replacement of the came with a uniformly sloped cam.

A first aspect provides a fluid flow control valve assembly for controlling a flow of fluid through an ablutionary fitting comprising:.

The fluid flow control valve assembly may allow for relatively fine user control of the flow of fluid through the ablutionary fitting.

The first flow control member and the second flow control member are arranged such that the fluid flow rate through the fluid flow control valve is always a non-zero value.

The first valve actuator may be arranged to cause linear movement of the second flow control member relative to the first flow control member.

The first valve actuator comprises a lever.

The second flow control member may be movable linearly relative to the first flow control member.

The first valve actuator may be arranged to cause rotation of the second flow control member relative to the first flow control member.

The second flow control member may be rotatable about an axis perpendicular to the second flow control member. The axis may be a central axis perpendicular to the second flow control member.

The first flow control member may be a first flow control plate.

The second flow control member may be a second flow control plate.

One or more of the flow channels may comprise an aperture passing through the first flow control member.

In an implementation, a length of the operating member may be adjustable.

The length of the operating member may be adjustable between a plurality of discrete lengths.

For instance, one or more connecting pieces may be utilised to change an effective length of the operating member. The connecting piece(s) may be configured to connect an end of the operating member to another elongate member. The connecting piece or connecting pieces may be configured to provide two or more different connecting piece lengths between the end of the operating member and the other elongate member,.

Alternatively, the length of the operating member may be adjustable to have any length within a range of lengths.

The ablutionary fitting may comprise a means operable to provide a principal stream of fluid, e.g. water, having a user-desired temperature. The means operable to provide the principal stream of fluid having the user-desired temperature may include, for example, a mixer valve, e.g. a thermostatic mixer valve, or an instantaneous water heater.

A second aspect provides a controller for use in a plumbing system or an ablutionary system, wherein the controller comprises a user input means operably connected to the operating member of a fluid flow control valve assembly according to the first aspect.

The user input means may include, for example, a touchscreen, a button, a lever or a rotary control member such as a rotary dial.

In an implementation, the user input means may comprise a rotary control member having a cam surface, the cam surface being configured to cause directly or indirectly linear movement of the operating member when a user rotates the rotary control member.

The controller may be a shower controller.

A third aspect provides a plumbing system or an ablutionary system comprising a fluid flow control valve assembly according to the first aspect and/or a controller according to the second aspect.

The plumbing system or the ablutionary system may comprise one or more fluid delivery devices downstream of the fluid control valve assembly.

The plumbing system or the ablutionary system may comprise a shower system.

Except where mutually exclusive, any of the features of any of the above described aspects may be employed mutatis mutandis in any of the other above described aspects.

Example embodiments will now be described with reference to the accompanying drawings, in which:.

<FIG> shows an example of a shower controller <NUM>. The shower controller <NUM> is configured to be fixed to a surface such as a wall.

The shower controller <NUM> comprises a casing <NUM>. The casing <NUM> is configured to shroud one or more fluid handling components and plumbing connections. The casing <NUM> may thus provide protect the one or more fluid handling components and plumbing connections from accidental damage or dirt ingress. The casing <NUM> may also provide the shower controller <NUM> with a desired appearance. The shape and dimensions of the casing <NUM> may be varied to provide different appearances, in order to provide different design aesthetics without necessarily having to change the arrangement of the one or more fluid handling components and plumbing connections shrouded by the casing <NUM>.

Typically, the casing <NUM> may shroud a thermostatic mixer valve (not shown). The thermostatic mixer valve may be connected to a supply of hot water and to a supply of cold water. The thermostatic mixer valve operates to mix the hot water and the cold water to produce a principal stream having a user-desired temperature. The principal stream having the user-desired temperature is then conveyed from an outlet of the thermostatic mixer valve to a fluid delivery device (not shown) such as a shower head downstream of the thermostatic mixer valve.

The shroud <NUM> generally comprises a front surface <NUM>, a side wall <NUM> extending in a rearward direction from the front surface <NUM> and an open end opposite the front surface <NUM>.

On the front surface <NUM> of the shower controller <NUM> there is a button <NUM> for turning on and off flow to the fluid delivery device. The button <NUM> may be operably coupled to an on-off valve having a first state that allows flow to the fluid delivery device and a second state that prevents flow to the fluid delivery device.

The shower controller <NUM> further comprises a first rotary control member <NUM> and a second rotary control member <NUM> disposed forward of the front surface <NUM>. The first rotary control member <NUM> is disposed forward of the second rotary control member <NUM>, i.e. the first rotary control member is further from the front surface <NUM> than the second rotary control member <NUM>.

The first rotary control member <NUM> provides temperature control. The second rotary control member <NUM> provides flow control.

The first rotary control member <NUM> comprises a first handle <NUM> to facilitate use thereof. The second rotary control member <NUM> comprises a second handle <NUM> to facilitate use thereof. The first rotary control member <NUM> and the second rotary control member <NUM> are configured to be rotatable about a common rotation axis normal to the front surface <NUM>.

The first rotary control member <NUM> is operably connected to the thermostatic mixer valve.

As will be described in more detail herein, the second rotary control member <NUM> is operably connected to a fluid flow control valve assembly downstream of the outlet of the thermostatic mixer valve.

<FIG> illustrates schematically an example of a shower system <NUM> comprising the shower controller <NUM>. The shower controller <NUM> is mounted on a wall <NUM>.

The casing <NUM> shrouds a thermostatic mixer valve (not shown). The thermostatic mixer valve is connected to a supply of hot water and to a supply of cold water. The thermostatic mixer valve operates to mix the hot water and the cold water to produce a principal stream having a user-desired temperature. The principal stream having the user-desired temperature is then conveyed from an outlet of the thermostatic mixer valve via a shower hose <NUM> to a shower head <NUM> downstream of the thermostatic mixer valve. A fluid flow control valve assembly (not shown) according to the present disclosure located downstream of the outlet of the thermostatic mixer valve is operable to control a flow of water from the outlet of the thermostatic mixer valve to the shower hose <NUM> and the shower head <NUM> connected thereto.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, there is shown an example of a fluid flow valve assembly <NUM>.

The fluid flow valve assembly <NUM> comprises a body <NUM> attached to a mounting plate <NUM> adapted to be fixed, in use, to a surface such as a wall. A thermostatic mixer valve assembly <NUM> is attached to the body <NUM> of the fluid flow valve assembly <NUM>. The body <NUM> is disposed between the mounting plate <NUM> and the thermostatic mixer valve assembly <NUM>.

The thermostatic mixer valve assembly <NUM> comprises a first inlet <NUM> configured to be adapted to a first fluid supply pipe and a second inlet <NUM> configured to be adapted to a second fluid supply pipe. The first fluid supply pipe may convey cold water and the second fluid supply pipe may convey hot water or vice versa.

The thermostatic mixer valve assembly <NUM> comprises a thermostatic mixer valve cartridge <NUM> including a thermostatic mixer valve. The thermostatic mixer valve has a first valve inlet in fluid communication with the first inlet <NUM> and a second valve inlet in fluid communication with the second inlet <NUM>. The thermostatic mixer valve operates to mix the hot water and the cold water to produce a principal stream having a user-desired temperature. The thermostatic mixer valve has an outlet <NUM> through which the principal stream having the user-desired temperature exits the thermostatic mixer valve cartridge <NUM>.

A waterway <NUM> within the body <NUM> is in fluid communication with the outlet <NUM>. Disposed within the waterway <NUM> is a first flow control member <NUM>. The first flow control member <NUM> extends across the waterway <NUM> and is fixed relative to the body <NUM>. The first flow control member <NUM> comprises a hub portion <NUM> with a central aperture therethrough. The hub portion <NUM> is connected to a mount portion <NUM> protruding from a base <NUM> of the waterway <NUM> within the body <NUM>.

The first flow control member <NUM> comprises a conical portion <NUM> extending radially outwards and upwards (i.e. in a direction away from the mount portion <NUM>) from the hub portion <NUM> to a rim <NUM>.

A plurality of apertures <NUM> in the conical portion <NUM> each provide a fluid flow channel through the first flow control member <NUM>.

The fluid flow control valve assembly <NUM> comprises a second flow control member <NUM> that is linearly moveable relative to the first flow control member <NUM>. The second flow control member <NUM> comprises a shaft <NUM> having a first end <NUM> and a second end <NUM>. From the first end <NUM> to the second end <NUM>, the shaft <NUM> extends through an aperture in the mount portion <NUM> and the central aperture in the hub portion <NUM> of the first flow control member <NUM>. The second flow control member <NUM> comprises a stopper portion <NUM> connected to the second end <NUM> of the shaft <NUM>. The stopper portion <NUM> extends radially and downwardly from the second end <NUM> of the shaft <NUM>. An O-ring <NUM> is disposed around the shaft <NUM> in a cavity defined by the mount portion <NUM> and the hub portion <NUM> of the first flow control member <NUM>. The O-ring <NUM> provides a fluid-tight seal around the shaft <NUM>.

An operating member <NUM> comprises a rod <NUM> received within a vertical channel in the body <NUM>. The operating member <NUM> comprises a foot portion <NUM> extending laterally from a lower end of the rod <NUM>. The foot portion <NUM> is perpendicular to the rod <NUM>. The foot portion <NUM> protrudes from the vertical channel and passes through a vertical slot. An end of the foot portion <NUM> distal from the rod <NUM> sits on top of a first end <NUM> of a lever <NUM>.

A second end <NUM> of the lever <NUM> is pivotally connected to the first end <NUM> of the shaft <NUM> of the second flow control member <NUM>. The lever <NUM> is configured to pivot, in use, about a fulcrum <NUM> between the first end <NUM> of the lever <NUM> and the second end <NUM> of the lever <NUM>. The distance from the first end <NUM> of the lever <NUM> to the fulcrum <NUM> is greater than the distance from the second end <NUM> of the lever <NUM> to the fulcrum <NUM>.

A connecting piece <NUM> comprising a tubular member with a blind hole in each end is disposed on an upper end of the rod <NUM> of the operating member <NUM>. The upper end of the rod <NUM> of the operating member <NUM> is received in one of the blind holes of the connecting piece <NUM>. An end of another elongate member (not shown) is received in the other of the blind holes of the connecting piece <NUM>. The other elongate member may be operably connected to a user input means (not shown) configured to cause linear movement of the other elongate member. The user input means may comprise, for example, a button, a lever, a slider or a rotary dial. For instance, the second rotary control member <NUM> (<FIG>) may have a cam surface on an underside thereof, the cam surface being configured to act on the other elongate member to cause linear movement of the other elongate member in a substantially vertical direction when a user rotates the second rotary control member <NUM>.

With reference to <FIG>, the linear movement of the other elongate member causes the linear movement of the operating member <NUM> in the vertical channel in the body <NUM>, as indicated by a first block arrow <NUM>. Consequently, the foot portion <NUM> of the operating member <NUM> acts on the first end <NUM> of the lever <NUM>, as indicated by a second block arrow <NUM>.

When, in use, the foot portion <NUM> of the operating member <NUM> pushes the first end <NUM> of the lever <NUM> down, the second flow control member <NUM> moves linearly in an upward direction relative to the first flow control member <NUM>. Consequently, the stopper portion <NUM> provides less of an obstruction to fluid flow through the apertures <NUM> in the conical portion <NUM> of the first flow control member <NUM>.

The lever <NUM> is biased against an underside of the foot portion <NUM> such that the first end <NUM> of the lever <NUM> remains in contact with the underside of the foot portion <NUM> during operation of the fluid flow control valve assembly <NUM>. Hence, when, in use, the foot portion <NUM> of the operating member <NUM> moves upwards, the first end <NUM> of the lever <NUM> moves upwards and the second end <NUM> of the lever <NUM> acts on the second flow control member <NUM> to move the second flow control member <NUM> linearly in a downward direction relative to the first flow control member <NUM>. Consequently, the stopper portion <NUM> provides more of an obstruction to fluid flow through the apertures <NUM> in the conical portion 113of the first flow control member <NUM>. The operating member <NUM> and the lever <NUM> may be configured such that the second flow control member <NUM> has a range of movement from a first end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to a greatest extent and a second end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to a least extent.

With reference to <FIG>, the connecting piece <NUM> may be configured such that an effective length of the operating member <NUM> may be varied, e.g. by inverting the connecting piece <NUM>, as indicated by a third block arrow <NUM>. Alternatively or additionally, the effective length of the operating member <NUM> may be varied by substituting the connecting piece <NUM> with a different connecting piece, in which the relative depths of the blind holes are different.

It will be appreciated that use of the connecting piece <NUM> in this way is only one example of a way of adjusting the length of the operating member <NUM>. Other ways of adjusting the length of the operating member <NUM> will be apparent to the person skilled in the art.

In some implementations, the connecting piece <NUM> and the other elongate member may not be present. In such an implementation, the user input means may act directly or indirectly on the upper end of the rod <NUM> of the operating member <NUM>.

In some implementations, the length of the operating member <NUM> may not be adjustable.

Adjusting the length of the operating member <NUM> allows the positions of the first end state and the second end state of the range of movement of the second flow control member <NUM> to be changed. Therefore, the fluid flow control valve assembly <NUM> can be configured to provide better or more appropriate fluid flow control for a given application when being installed at a site of use. The selected configuration for providing better or more appropriate fluid flow control may depend, for example, on the pressure of the mains water supply at a given site of use.

<FIG> and <FIG> show three sectional views of a portion of the fluid flow control valve assembly <NUM> and illustrate how the first end state and the second end state of the range of movement of the second flow control member <NUM> can be changed by adjusting the effective length of the operating member <NUM>, e.g. by using the connecting piece <NUM>. In this example, the connecting piece <NUM> is configured such that the operating member has a first effective length when the connecting piece <NUM> is in a first orientation and a second effective length when the connecting piece <NUM> has been inverted such that the connecting piece is in a second orientation. In this example, the second effective length of the operating member <NUM> is longer than the first effective length of the operating member <NUM>.

<FIG> illustrates a scenario wherein the operating member <NUM> has the first effective length. The second flow control member <NUM> is shown in the first end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to the greatest extent. The stopper portion <NUM> is resting on the conical portion <NUM> of the first flow control member <NUM>.

<FIG> further illustrates the scenario wherein the operating member <NUM> has the first effective length. The second flow control member <NUM> is shown in the second end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to the least extent. There is a gap between the stopper portion <NUM> and the conical portion <NUM> of the first flow control member <NUM>.

The scenarios illustrated in <FIG> may be appropriate for providing fluid flow control at a site of use having a high pressure mains water supply. It will be appreciated that <FIG> illustrates the lowest flow condition and <FIG> illustrates the highest flow condition through the fluid flow control valve assembly <NUM> with the operating member <NUM> having the first effective length.

Alternatively, <FIG> may illustrate a scenario wherein the operating member <NUM> has the second effective length. The second flow control member <NUM> is shown in the first end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to the least extent. There is a gap between the stopper portion <NUM> and the conical portion <NUM> of the first flow control member <NUM>.

<FIG> further illustrates the scenario wherein the operating member <NUM> has the second effective length. The second flow control member <NUM> is shown in the second end state wherein the stopper portion <NUM> obstructs fluid flow through the apertures <NUM> of the first flow control member <NUM> to the least extent. There is a larger gap between the stopper portion <NUM> and the conical portion <NUM> of the first flow control member <NUM>.

The alternative scenario illustrated in <FIG> and <FIG> may be appropriate for providing fluid flow control at a site of use having a low pressure mains water supply. It will be appreciated that <FIG> illustrates the lowest flow condition and <FIG> illustrates the highest flow condition through the fluid flow control valve assembly <NUM> with the operating member <NUM> having the second effective length.

Referring to <FIG>, <FIG> and <FIG>, there is shown another example of a fluid flow control valve assembly <NUM>.

The thermostatic mixer valve assembly <NUM> comprises a first inlet configured to be adapted to a first fluid supply pipe and a second inlet configured to be adapted to a second fluid supply pipe. The first fluid supply pipe may convey cold water and the second fluid supply pipe may convey hot water or vice versa.

The thermostatic mixer valve assembly <NUM> comprises a thermostatic mixer valve cartridge <NUM> including a thermostatic mixer valve. The thermostatic mixer valve has a first valve inlet in fluid communication with the first inlet and a second valve inlet in fluid communication with the second inlet. The thermostatic mixer valve operates to mix the hot water and the cold water to produce a principal stream having a user-desired temperature. The thermostatic mixer valve has an outlet <NUM> through which the principal stream having the user-desired temperature exits the thermostatic mixer valve cartridge <NUM>.

A waterway <NUM> within the body <NUM> is in fluid communication with the outlet <NUM>. Disposed within the waterway <NUM> is a first flow control member <NUM>. The first flow control member <NUM> extends across the waterway <NUM> and is fixed relative to the body <NUM>. A plurality of apertures <NUM> each provide a fluid flow channel through the first flow control member <NUM>. The first flow control member <NUM> may be considered a first flow control plate.

The fluid flow control valve assembly <NUM> comprises a second flow control member <NUM> that is rotatable relative to the first control member <NUM>. The second flow control member <NUM> may be considered a second flow control plate.

The second flow control member <NUM> is adjacent the first flow control member <NUM>. As illustrated, the second flow control member <NUM> is beneath the first flow control member <NUM>. The second flow control member <NUM> has apertures therethrough. As will be described in more detail below, rotation of the second flow control member <NUM> relative to the first flow control member <NUM> brings the apertures in the second flow control member <NUM> into or out of alignment with the apertures <NUM> in the first flow control member <NUM> to permit more fluid flow or less fluid flow respectively. The apertures in the first flow control member <NUM> and the second flow control member <NUM> are configured such that bringing them into or out of alignment with each other provides continuous and gradual fluid flow control, i.e. substantially free of any sudden, relatively large increases or decreases, e.g. step changes, in fluid flow.

The first flow control member <NUM> may be made from a plastics material or a ceramic material. The second flow control member <NUM> may be made from a plastics material or a ceramic material.

With reference, in particular, to <FIG>, an operating member <NUM> comprises a rod <NUM> received within a vertical channel (not shown) in the body <NUM> (<FIG>). The operating member <NUM> comprises a foot portion <NUM> extending laterally from a lower end of the rod <NUM>. The foot portion <NUM> is perpendicular to the rod <NUM>. The foot portion <NUM> protrudes from the vertical channel and passes through a vertical slot. An end of the foot portion <NUM> distal from the rod <NUM> sits on top of a first end <NUM> of a lever <NUM>.

The lever <NUM> is configured to pivot, in use, about a fulcrum <NUM> between the first end <NUM> of the lever <NUM> and a second end <NUM> of the lever <NUM>. The distance from the first end <NUM> of the lever <NUM> to the fulcrum <NUM> is greater than the distance from the second end <NUM> of the lever <NUM> to the fulcrum <NUM>.

At the fulcrum <NUM>, the lever <NUM> is connected to a first end of an axle <NUM> extending perpendicularly from the lever <NUM>. A second end of the axle is attached to a paddle <NUM>. A tip of the paddle <NUM> distal from the axle <NUM> is disposed between a first retaining projection <NUM> and a second retaining projection <NUM>, each one of the first retaining projection <NUM> and the second retaining projection <NUM> extending downwardly from the second flow control member <NUM>. The first and second retaining projections <NUM>, <NUM> are spaced apart and dimensioned such that the tip of the paddle <NUM> is always located, in use, between the first and second retaining projections <NUM>, <NUM>.

At an intermediate point, an O-ring <NUM> surrounds the axle <NUM> to prevent fluid from escaping the waterway <NUM> (<FIG>) and getting to the lever <NUM>. At a point between the O-ring <NUM> and the first end of the axle <NUM>, the axle <NUM> is mounted on a bearing <NUM>.

A spring <NUM> is configured to act on the second end <NUM> of the lever <NUM> to bias the lever <NUM> such that the first end <NUM> of the lever <NUM> remains in contact with an underside of the foot portion <NUM> during operation of the fluid flow control valve assembly <NUM>.

An upper end of the rod <NUM> may be acted upon directly or indirectly, e.g. in a manner similar to that described above in relation to the operation of the fluid flow control valve assembly <NUM>, to cause linear movement of the operating member <NUM>.

When, in use, the foot portion <NUM> pushes the first end <NUM> of the lever <NUM> down, the axle <NUM> is caused to rotate in an anticlockwise direction (when viewed from the first end of the axle <NUM>). Consequently, the tip of the paddle <NUM> pushes against the second retaining projection <NUM> to cause clockwise rotation of the second flow control member <NUM> relative to the first flow control member <NUM> (when viewed from beneath the second flow control member <NUM>.

When, in use, the operating member <NUM> move upwards, the spring <NUM> acts to push the first end <NUM> of the lever <NUM> up. Consequently, the axle <NUM> is caused to rotate in a clockwise direction (when viewed from the first end of the axle <NUM>). Consequently, the tip of the paddle <NUM> pushes against the first retaining projection <NUM> to cause anticlockwise rotation of the second flow control member <NUM> relative to the first flow control member <NUM> (when viewed from beneath the second flow control member <NUM>).

The length of the operating member <NUM> may or may not be adjustable. The length of the operating member <NUM> may be adjustable, e.g. in a manner similar to that described above in relation to the operation of the fluid flow control valve assembly <NUM>.

Various modifications may be made to the example embodiments described herein without departing from the scope of the invention.

According to the invention, the first flow control member and the second flow control member are arranged such that, in use, the fluid flow rate through the fluid flow control valve is always a non-zero value.

In some implementations, there may be more than one fluid delivery device downstream of the fluid flow control valve assembly. A diverter may be disposed downstream of the fluid flow control valve assembly to allow a user to select any combination of the fluid delivery devices at a given time. Alternatively, a fluid flow control valve assembly according to this disclosure may be disposed downstream of one or more of the outlets of the diverter, to allow a user to control flow to a downstream fluid delivery device.

Generally, the fluid flow control valve assemblies disclosed herein may be relatively simple mechanically. The fluid flow control valve assemblies disclosed herein may require only a relatively low force to actuate them, which may be beneficial for users, in particular, but not exclusively, users with reduced strength and/or manual dexterity. The fluid flow control valve assemblies disclosed herein may be employed with a variety of user input means, including, for example, a touchscreen, a button, a lever or a rotary dial. Accordingly, the fluid flow control valve assemblies disclosed herein may be utilised in or with a range of ablutionary or plumbing fittings having a variety of design aesthetics.

Claim 1:
A fluid flow control valve assembly for controlling a flow of fluid through an ablutionary fitting comprising:
a fluid flow control valve comprising:
a first flow control member comprising one or more flow channels;
a second flow control member disposed adjacent to the first flow control member, wherein the second flow control member is moveable relative to the first flow control member;
a first valve actuator arranged to cause movement of the second flow control member relative to the first flow control member; and
an operating member operably connected to the first valve actuator;
wherein, in use, the operating member is operable to be moved in a linear direction and the operating member acts in turn on the first valve actuator to move the second flow control member, wherein movement of the second flow control member adjusts the position of the second flow control member relative to the one or more flow channels in the first flow control member such that a flow rate through the fluid flow control valve may be increased or decreased characterized in that
the first flow control member and the second flow control member are arranged such that the fluid flow rate through the fluid flow control valve is always a non-zero value and wherein the first valve actuator comprises a lever.