Patent Description:
<CIT> discloses a flow modulator for a fluid having a housing and a valve body. The valve body is provided by a foil element. The foil element has an opening for the fluid. The foil element is carried by a driver. The driver and the foil element are both positioned within a chamber of the housing. The driver and the foil element are both linear displaceable within the chamber of the housing thereby changing an overlap between an opening of the housing and the opening of the foil element.

<CIT> discloses another flow modulator for a fluid comprising a housing, a modulator body, and a valve body. The modulator body has a flow channel and an opening providing together a flow passage for the fluid. The valve body is provided by a foil element. The foil element has an opening for the fluid. The foil element is rotatable relative to the modulator body to modulate the flow of the fluid by adjusting an overlap between the opening of the valve body and the flow passage of the modulator body.

<CIT> discloses a flow modulator according to the preamble of claim <NUM>.

Against this background, a novel flow modulator for a fluid like combustion gas is provided.

The novel flow modulator for a fluid like combustion gas according to the present disclosure comprises a modulator body having a channel providing a flow passage for the fluid.

The novel flow modulator further comprises a valve body having an opening providing another flow passage for the fluid.

The novel flow modulator further comprises an actuator by which the valve body is rotatably displaceable relative to the modulator body to modulate the fluid flow by changing the overlap between the opening of the valve body and the channel of the modulator body.

The novel flow modulator further comprises a gear transmission, wherein an input side of the gear transmission is in operative connection with the actuator having a fixed axis of rotation, and wherein an output side of the gear transmission is in operative connection with the valve body having a translationally displaceable axis of rotation.

The novel flow modulator provides a reliable flow modulation of the fluid. The gear transmission of the flow modulator allows for a tolerance-compensation within the flow modulator, namely to compensate component tolerance of the flow modulator. Simple and inexpensive assembly of the flow modulator is possible. A large resolution of flow resistance is made possible by a respective transmission ratio of the gear transmission.

The valve body has a guide pin being positioned in the axis of rotation of the valve body, and the modulator body has a guide groove for the guide pin of the valve body, wherein the guide groove is configured to allow a rotational displacement of the valve body relative to the modulator body, is further configured to allow a translational displacement of the valve body relative to the modulator body in a distance direction of the axis of rotation of the actuator and the axis of rotation of the valve body, and is further configured to prevent a translational displacement of the valve body relative to the modulator body diagonal and/or orthogonal to said distance direction of the axis of rotation of the actuator and the axis of rotation of the valve body. The allows for a very favorable tolerance-compensation within the flow modulator.

Preferably, the the gear transmission comprises a first toothing provided by a drive wheel, the gear transmission comprises a second toothing provided by the valve body, wherein the first toothing is in operative connection with the second toothing. Preferably, the valve body has a circumferential groove, wherein the drive wheel is at least partially positioned within said circumferential groove, and wherein the circumferential groove has radial width being configured to allow rotation of the valve body relative to the modulator body around the axis of rotation of the valve body while keeping the first toothing of the drive wheel always in operative connection with the second toothing of the valve body. This allows a favorable tolerance-compensation within the flow modulator while providing a simple and inexpensive assembly of the flow modulator.

The first toothing may be provided by a section of the drive wheel that is at least partially positioned within said circumferential groove, while the second toothing is provided by a wall of the circumferential groove. Alternatively, the first toothing is provided by a section of the drive wheel that is positioned outside of said circumferential groove, while the second toothing is provided by a wall of the valve body.

Preferred developments of the invention are provided by the dependent claims and the description of the drawings. Exemplary embodiments are explained in more detail on the basis of the drawing, in which:.

The present invention relates to a flow modulator <NUM> for a fluid, preferably for a gaseous fluid like combustion gas. The flow modulator <NUM> is preferably part of a gas burner appliance of a heating system. A flow modulator for a gaseous fluid can also be called gas flow modulator.

<FIG> show different views of flow modulators <NUM> according to the invention. Identical reference signs are used for identical or similar parts.

The flow modulator <NUM> comprises a modulator body <NUM>.

The modulator body <NUM> may be part of a housing <NUM>. The housing <NUM>, namely a side wall 12a of the housing <NUM>, provides an opening <NUM> acting as inlet port for the fluid. The modulator body <NUM> may provide a bottom wall 12b of the housing <NUM>.

The modulator body <NUM> has a channel <NUM> providing a flow passage <NUM> for the fluid. Said channel <NUM> or flow passage <NUM> is in communication with an opening <NUM> acting as outlet port for the fluid.

A top wall 12c of the housing <NUM> delimits together with the bottom wall 12b and the side walls 12a an interior space <NUM> of the housing <NUM>.

It should be noted that the flow direction of the fluid may also be in the opposite way. In this case the opening <NUM> acts as inlet port for the fluid and the opening <NUM> acts as outlet port for the fluid.

The flow modulator <NUM> further comprises a valve body <NUM>. The valve body <NUM> is positioned within the interior space <NUM> of the housing <NUM>. The valve body <NUM> has an opening <NUM> providing another flow passage <NUM> for the fluid.

The flow modulator <NUM> further comprises an actuator <NUM>. The actuator <NUM> may be an electrical motor like a stepper motor.

By use of the actuator <NUM> the valve body <NUM> is rotatably displaceable relative to the modulator body <NUM> to modulate the fluid flow. The fluid flow is modulated by changing the overlap between the opening <NUM> or flow passage <NUM> of the valve body <NUM> and the channel <NUM> of flow passage <NUM> of the modulator body <NUM>.

The flow modulator <NUM> further comprises a gear transmission <NUM>.

An input side of the gear transmission <NUM> is in operative connection with the actuator <NUM> having a fixed axis of rotation <NUM>.

An output side of the gear transmission <NUM> is in operative connection with the valve body <NUM> having a translationally displaceable axis of rotation <NUM>.

The valve body <NUM> has a guide pin <NUM> being positioned in the axis of rotation <NUM> of the valve body <NUM>. The modulator body <NUM> has a guide groove <NUM> for the guide pin <NUM> of the valve body <NUM>.

The guide groove <NUM> is configured to allow a rotational displacement of the valve body <NUM> relative to the modulator body <NUM>.

The guide groove <NUM> is further configured to allow a translational displacement of the valve body <NUM> relative to the modulator body <NUM> in a distance direction X of the axis of rotation <NUM> of the actuator <NUM> and the axis of rotation <NUM> of the valve body <NUM>.

However, the guide groove <NUM> is further configured to prevent a translational displacement of the valve body <NUM> relative to the modulator body <NUM> diagonal and/or orthogonal to said distance direction X of the axis of rotation <NUM> of the actuator <NUM> and the axis of rotation <NUM> of the valve body <NUM>.

The guide pin <NUM> of the valve body may be a cylinder. The guide groove <NUM> of modulator body <NUM> may be an oblong hole.

The dimension of the guide groove <NUM> in said distance direction X of the axis of rotation <NUM> of the actuator <NUM> and the axis of rotation <NUM> of the valve body <NUM> is larger than the diameter of the guide pin <NUM> thereby allowing the translational displacement of the valve body <NUM> relative to the modulator body11 in said distance direction X.

The dimension of the guide groove <NUM> orthogonal to said distance direction X of the axis of rotation <NUM> of the actuator <NUM> and the axis of rotation <NUM> of the valve body <NUM> is adapted to the diameter of the guide pin <NUM> thereby preventing the translational displacement of the valve body <NUM> relative to the modulator body <NUM> diagonal and/or orthogonal to said distance direction X.

The gear transmission <NUM> comprises a first toothing <NUM> provided by a drive wheel <NUM>. The drive wheel <NUM> provides or corresponds to the input side of the gear transmission <NUM>.

The gear transmission <NUM> further comprises a second toothing <NUM> provided by the valve body <NUM>. The valve body <NUM> provides or corresponds to the output side of the gear transmission <NUM>.

The first toothing <NUM> is in operative connection with the second toothing <NUM>. The first toothing <NUM> and the second toothing <NUM> comb directly into each other thereby providing a single-stage transmission. However, by using at least one further toothing between the first toothing <NUM> and the second toothing <NUM> a multi-stage transmission may be provided.

The valve body <NUM> has a circumferential groove <NUM>. The drive wheel <NUM> connected to the axis of rotation <NUM> of the actuator <NUM> is at least partially positioned within said circumferential groove <NUM>.

The circumferential groove <NUM> has radial width being configured to allow rotation of the valve body <NUM> relative to the modulator body <NUM> around the axis of rotation <NUM> of the valve body <NUM> while keeping the first toothing <NUM> of the drive wheel <NUM> always in operative connection with the second toothing <NUM> of the valve body <NUM>.

In the embodiment of <FIG>, the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is at least partially positioned within said circumferential groove <NUM>, while the second toothing <NUM> is provided a wall of the circumferential groove <NUM>, namely by a radial outer wall 30a of the circumferential groove <NUM>.

In the embodiment of <FIG>, the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is at least partially positioned within said circumferential groove <NUM>, while the second toothing <NUM> is provided a wall of the circumferential groove <NUM>, namely by a radial inner wall 30b of the circumferential groove <NUM>.

In the embodiment of <FIG>, the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is at positioned outside of said circumferential groove <NUM>, while the second toothing <NUM> is provided by a wall <NUM> of the valve body <NUM>, namely as an internal toothing of said wall <NUM>.

In the embodiment of <FIG>, the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is at positioned outside of said circumferential groove <NUM>, while the second toothing <NUM> is provided by a wall <NUM> of the valve body <NUM>, namely as an external toothing of said wall <NUM>.

The embodiments of <FIG> differ from each other by the technical design of the first toothing <NUM> and the second toothing <NUM>.

In the embodiment of <FIG> and in the embodiment of <FIG> the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is at least partially positioned within said circumferential groove <NUM> and the second toothing <NUM> is provided by a wall of the circumferential groove <NUM>. The opposite wall of the groove <NUM> does not have a toothing and is smooth. In the embodiment of <FIG> and in the embodiment of <FIG> the first toothing <NUM> is provided by a section of the drive wheel <NUM> that is positioned outside said circumferential groove <NUM> and the second toothing <NUM> is provided a wall <NUM> of the valve body <NUM>. In these embodiments both opposite walls of the groove <NUM> are smooth.

Nevertheless, in all embodiments the groove <NUM> of the valve body <NUM> has radial width being configured to allow the rotation of the valve body <NUM> relative to the modulator body <NUM> around the axis of rotation <NUM> of the valve body <NUM> while keeping the first toothing <NUM> of the drive wheel <NUM> always in operative connection with the second toothing <NUM> of the valve body <NUM>. The drive wheel <NUM> bears against a respective wall of the groove <NUM> depending on the position and/or displacement of the valve body <NUM>.

The circumferential groove <NUM> has radial width being configured to provide a radial play between the drive wheel <NUM> and the valve body <NUM> allowing the rotation of the valve body <NUM> relative to the modulator body <NUM> around the axis of rotation <NUM> of the valve body <NUM> while keeping the first toothing <NUM> of the drive wheel <NUM> always in operative connection with the second toothing <NUM> of the valve body <NUM>.

Claim 1:
Flow modulator (<NUM>) for a fluid like combustion gas, comprising:
a modulator body (<NUM>) having a channel (<NUM>) providing a flow passage (<NUM>) for the fluid;
a valve body (<NUM>) having an opening (<NUM>) providing another flow passage (<NUM>) for the fluid;
an actuator (<NUM>) by which the valve body (<NUM>) is rotatably displaceable relative to the modulator body (<NUM>) to modulate the fluid flow by changing the overlap between the opening (<NUM>) or flow passage (<NUM>) of the valve body (<NUM>) and the channel (<NUM>) or flow passage (<NUM>) of the modulator body (<NUM>);
a gear transmission (<NUM>),
wherein an input side of the gear transmission (<NUM>) is in operative connection with the actuator (<NUM>) having a fixed axis of rotation (<NUM>),
wherein
an output side of the gear transmission (<NUM>) is in operative connection with the valve body (<NUM>) having a translationally displaceable axis of rotation (<NUM>),
and wherein the valve body (<NUM>) has a guide pin (<NUM>) being positioned in the axis of rotation (<NUM>) of the valve body (<NUM>), characterised in that
the modulator body (<NUM>) has a guide groove (<NUM>) for the guide pin (<NUM>) of the valve body (<NUM>), wherein the guide groove (<NUM>) is configured to
allow a rotational displacement of the valve body (<NUM>) relative to the modulator body (<NUM>),
allow a translational displacement of the valve body (<NUM>) relative to the modulator body (<NUM>) in a distance direction (X) of the axis of rotation (<NUM>) of the actuator (<NUM>) and the axis of rotation (<NUM>) of the valve body (<NUM>),
prevent a translational displacement of the valve body (<NUM>) relative to the modulator body (<NUM>) diagonal and/or orthogonal to said distance direction (X) of the axis of rotation (<NUM>) of the actuator (<NUM>) and the axis of rotation (<NUM>) of the valve body (<NUM>).